Visualizing cancer-originating acetate uptake through monocarboxylate transporter 1 in reactive astrocytes in the glioblastoma tumor microenvironment

BACKGROUND

Reactive astrogliosis is a hallmark of various brain pathologies, including neurodegenerative diseases and glioblastomas. However, the specific intermediate metabolites contributing to reactive astrogliosis remain unknown. This study investigated how glioblastomas induce reactive astrogliosis in the neighboring microenvironment and explore 11C-acetate PET as an imaging technique for detecting reactive astrogliosis.

METHODS

Through in vitro, mouse models, and human tissue experiments, we examined the association between elevated 11C-acetate uptake and reactive astrogliosis in gliomas. We explored acetate from glioblastoma cells, which triggers reactive astrogliosis in neighboring astrocytes by upregulating MAO-B and monocarboxylate transporter 1 (MCT1) expression. We evaluated the presence of cancer stem cells in the reactive astrogliosis region of glioblastomas and assessed the correlation between the volume of 11C-acetate uptake beyond MRI and prognosis.

RESULTS

Elevated 11C-acetate uptake is associated with reactive astrogliosis and astrocytic MCT1 in the periphery of glioblastomas in human tissues and mouse models. Glioblastoma cells exhibit increased acetate production as a result of glucose metabolism, with subsequent secretion of acetate. Acetate derived from glioblastoma cells induces reactive astrogliosis in neighboring astrocytes by increasing the expression of MAO-B and MCT1. We found cancer stem cells within the reactive astrogliosis at the tumor periphery. Consequently, a larger volume of 11C-acetate uptake beyond contrast-enhanced MRI was associated with a worse prognosis.

CONCLUSIONS

Our results highlight the role of acetate derived from glioblastoma cells in inducing reactive astrogliosis and underscore the potential value of 11C-acetate PET as an imaging technique for detecting reactive astrogliosis, offering important implications for the diagnosis and treatment of glioblastomas.

4-EA-NBOMe, an amphetamine derivative, alters glutamatergic synaptic transmission through 5-HT1A receptors on cortical neurons from SpragueDawley rat and pyramidal neurons from C57BL/6 mouse

New psychoactive substances (NPSs) are compounds designed to mimic illegal recreational drugs. In particular, there are difficulties in legal restrictions because there is no fast NPS detection method to suppress the initial spread of NPS with criminal records; thus, they expose the public to serious health threats, including toxicity and dependence. However, the effects of NPSs on the brain and the related cellular mechanisms are well unknown. One of the recently emerging drugs is 4-ethylamphetamine-NBOMe (4-EA-NBOMe), a member of the 2 C phenylalanine family with a similar structure to methamphetamine (methA). In this study, we tested the effect of methA analogs on the glutamatergic synaptic transmission on primary cultured cortical neurons of SpragueDawley (SD) rats and C57BL/6 mice, and also layer 2/3 pyramidal neurons of the medial prefrontal cortex (mPFC) of C57BL/6 mice. We found that acute treatment with 4-EA-NBOMe inhibits spontaneous excitatory postsynaptic currents (EPSCs) and that withdrawal after chronic inhibition by 4-EA-NBOMe augments glutamatergic synaptic transmission. These modifications of synaptic responses are mediated by 5-HT_1A receptors. These findings suggest that 4-EA-NBOMe directly affects the central nervous system by changing the efficacy of glutamatergic synaptic transmission.

Body mass index at diagnosis of a childhood brain tumor; a reflection of hypothalamic-pituitary dysfunction or lifestyle?

PURPOSE

Childhood brain tumor survivors (CBTS) are at risk of becoming overweight, which has been shown to be associated with hypothalamic-pituitary (HP) dysfunction during follow-up. Body mass index (BMI) at diagnosis is related to BMI at follow-up. It is uncertain, however, whether aberrant BMI at brain tumor diagnosis reflects early hypothalamic dysfunction or rather reflects genetic and sociodemographic characteristics. We aimed to examine whether BMI at childhood brain tumor diagnosis is associated with HP dysfunction at diagnosis or its development during follow-up.

METHODS

The association of BMI at diagnosis of a childhood brain tumor to HP dysfunction at diagnosis or during follow-up was examined in a Dutch cohort of 685 CBTS, excluding children with craniopharyngioma or a pituitary tumor. Individual patient data were retrospectively extracted from patient charts.

RESULTS

Of 685 CTBS, 4.7% were underweight, 14.2% were overweight, and 3.8% were obese at diagnosis. Being overweight or obese at diagnosis was not associated with anterior pituitary deficiency or diabetes insipidus at diagnosis or during follow-up. In children with suprasellar tumors, being obese at diagnosis was associated with central precocious puberty.

CONCLUSION

Overweight or obesity at diagnosis of a childhood brain tumor seems not to be associated with pituitary deficiencies. These results suggest that genetics and lifestyle may be more important etiologic factors for higher BMI at diagnosis in these children than hypothalamic dysfunction. To improve the long-term outcome of CBTS with regards to overweight and obesity, more attention should be given to lifestyle already at the time of brain tumor treatment.

Classification of advanced methods for evaluating neurotoxicity

Purpose of review

As fields such as neurotoxicity evaluation and neuro-related drug research are increasing in popularity, there is a demand for the expansion of neurotoxicity research. Currently, neurotoxicity is assessed by measuring changes in weight and behavior. However, measurement of such changes does not allow the detection of subtle and inconspicuous neurotoxicity. In this review, methods for advancing neurotoxicity research are divided into molecule-, cell-, circuit-, and animal model-based methods, and the results of previous studies assessing neurotoxicity are provided and discussed.

Recent findings

In coming decades, cooperation between universities, national research institutes, industrial research institutes, governments, and the private sector will become necessary when identifying alternative methods for neurotoxicity evaluation, which is a current goal related to improving neurotoxicity assessment and an appropriate approach to neurotoxicity prediction. Many methods for measuring neurotoxicity in the field of neuroscience have recently been reported. This paper classifies the supplementary and complementary experimental measures for evaluating neurotoxicity.

Prevalence and risk factors of hypothalamic-pituitary dysfunction in infant and toddler childhood brain tumor survivors

OBJECTIVE

Childhood brain tumor survivors (CBTS) are at risk to develop hypothalamic-pituitary (HP) dysfunction (HPD). The risk for HPD may vary between different age groups due to maturation of the brain and differences in oncologic treatment protocols. Specific studies on HPD in infant brain tumor survivors (infant-BTS, 0-1 years at diagnosis) or toddler brain tumor survivors (toddler-BTS, ≥1-3 years) have not been performed.

PATIENTS AND METHODS

A retrospective nationwide cohort study in CBTS was performed. Prevalence and risk factors for HPD were compared between infant-, toddler-, and older-BTS. Subgroup analysis was performed for all non-irradiated CBTS (n = 460).

RESULTS

In total, 718 CBTS were included, with a median follow-up time of 7.9 years. Overall, despite the less frequent use of radiotherapy (RT) in infants, no differences in the prevalence of HPD were found between the three groups. RT (OR: 16.44; 95% CI: 8.93-30.27), suprasellar tumor location (OR: 44.76; 95% CI: 19.00-105.49), and younger age (OR: 1.11; 95% CI: 1.05-1.18) were associated with HP dysfunction. Infant-BTS and toddler-BTS showed more weight gain (P < 0.0001) and smaller height SDS (P = 0.001) during follow-up. In non-irradiated CBTS, infant-BTS and toddler-BTS were significantly more frequently diagnosed with TSH-, ACTH-, and ADH deficiency, compared to older-BTS.

CONCLUSION

Infant and toddler brain tumor survivors seem to be more vulnerable to develop HP dysfunction than older children. These results emphasize the importance of special infant and toddler brain tumor treatment protocols and the need for endocrine surveillance in children treated for a brain tumor at a young age.

Mechanisms of Invasion in Glioblastoma: Extracellular Matrix, Ca2+ Signaling, and Glutamate

Glioblastoma (GBM) is the most common and malignant form of primary brain tumor with a median survival time of 14–16 months in GBM patients. Surgical treatment with chemotherapy and radiotherapy may help increase survival by removing GBM from the brain. However, complete surgical resection to eliminate GBM is almost impossible due to its high invasiveness. When GBM cells migrate to the brain, they interact with various cells, including astrocytes, neurons, endothelial cells, and the extracellular matrix (ECM). They can also make their cell body shrink to infiltrate into narrow spaces in the brain; thereby, they can invade regions of the brain and escape from surgery. Brain tumor cells create an appropriate microenvironment for migration and invasion by modifying and degrading the ECM. During those processes, the Ca²⁺ signaling pathway and other signaling cascades mediated by various ion channels contribute mainly to gene expression, motility, and invasion of GBM cells. Furthermore, GBM cells release glutamate, affecting migration via activation of ionotropic glutamate receptors in an autocrine manner. This review focuses on the cellular mechanisms of glioblastoma invasion and motility related to ECM, Ca²⁺ signaling, and glutamate. Finally, we discuss possible therapeutic interventions to inhibit invasion by GBM cells.

Tumor Spheroids of an Aggressive Form of Central Neurocytoma Have Transit-Amplifying Progenitor Characteristics with Enhanced EGFR and Tumor Stem Cell Signaling

Central neurocytoma (CN) has been known as a benign neuronal tumor. In rare cases, CN undergoes malignant transformation to glioblastomas (GBM). Here we examined its cellular origin by characterizing differentiation potential and gene expression of CN-spheroids. First, we demonstrate that both CN tissue and cultured primary cells recapitulate the hierarchal cellular composition of subventricular zone (SVZ), which is comprised of neural stem cells (NSCs), transit amplifying progenitors (TAPs), and neuroblasts. We then derived spheroids from CN which displayed EGFR+/MASH+ TAP and BLBP+ radial glial cell (RGC) characteristic, and mitotic neurogenesis and gliogenesis by single spheroids were observed with cycling multipotential cells. CN-spheroids expressed increased levels of pluripotency and tumor stem cell genes such as KLF4 and TPD5L1, when compared to their differentiated cells and human NSCs. Importantly, Gene Set Enrichment Analysis showed that gene sets of GBM-Spheroids, EGFR Signaling, and Packaging of Telomere Ends are enriched in CN-spheroids in comparison with their differentiated cells. We speculate that CN tumor stem cells have TAP and RGC characteristics, and upregulation of EGFR signaling as well as downregulation of eph-ephrin signaling have critical roles in tumorigenesis of CN. And their ephemeral nature of TAPs destined to neuroblasts, might reflect benign nature of CN.

Signaling mechanisms of μ-opioid receptor (MOR) in the hippocampus: disinhibition versus astrocytic glutamate regulation

μ-opioid receptor (MOR) is a class of opioid receptors that is critical for analgesia, reward, and euphoria. MOR is distributed in various brain regions, including the hippocampus, where traditionally, it is believed to be localized mainly at the presynaptic terminals of the GABAergic inhibitory interneurons to exert a strong disinhibitory effect on excitatory pyramidal neurons. However, recent intensive research has uncovered the existence of MOR in hippocampal astrocytes, shedding light on how astrocytic MOR participates in opioid signaling via glia-neuron interaction in the hippocampus. Activation of astrocytic MOR has shown to cause glutamate release from hippocampal astrocytes and increase the excitability of presynaptic axon fibers to enhance the release of glutamate at the Schaffer Collateral-CA1 synapses, thereby, intensifying the synaptic strength and plasticity. This novel mechanism involving astrocytic MOR has been shown to participate in hippocampus-dependent conditioned place preference. Furthermore, the signaling of hippocampal MOR, whose action is sexually dimorphic, is engaged in adult neurogenesis, seizure, and stress-induced memory impairment. In this review, we focus on the two profoundly different hippocampal opioid signaling pathways through either GABAergic interneuronal or astrocytic MOR. We further compare and contrast their molecular and cellular mechanisms and their possible roles in opioid-associated conditioned place preference and other hippocampus-dependent behaviors.

Activation of Astrocytic μ-Opioid Receptor Causes Conditioned Place Preference

The underlying mechanisms of how positive emotional valence (e.g., pleasure) causes preference of an associated context is poorly understood. Here, we show that activation of astrocytic μ-opioid receptor (MOR) drives conditioned place preference (CPP) by means of specific modulation of astrocytic MOR, an exemplar endogenous Gi protein-coupled receptor (Gi-GPCR), in the CA1 hippocampus. Long-term potentiation (LTP) induced by a subthreshold stimulation with the activation of astrocytic MOR at the Schaffer collateral pathway accounts for the memory acquisition to induce CPP. This astrocytic MOR-mediated LTP induction is dependent on astrocytic glutamate released upon activation of the astrocytic MOR and the consequent activation of the presynaptic mGluR1. The astrocytic MOR-dependent LTP and CPP were recapitulated by a chemogenetic activation of astrocyte-specifically expressed Gi-DREADD hM4Di. Our study reveals that the transduction of inhibitory Gi-signaling into augmented excitatory synaptic transmission through astrocytic glutamate is critical for the acquisition of contextual memory for CPP.

Ephaptic Coupling Promotes Synchronous Firing of Cerebellar Purkinje Cells

Correlated neuronal activity at various timescales plays an important role in information transfer and processing. We find that in awake-behaving mice, an unexpectedly large fraction of neighboring Purkinje cells (PCs) exhibit sub-millisecond synchrony. Correlated firing usually arises from chemical or electrical synapses, but, surprisingly, neither is required to generate PC synchrony. We therefore assessed ephaptic coupling, a mechanism in which neurons communicate via extracellular electrical signals. In the neocortex, ephaptic signals from many neurons summate to entrain spiking on slow timescales, but extracellular signals from individual cells are thought to be too small to synchronize firing. Here we find that a single PC generates sufficiently large extracellular potentials to open sodium channels in nearby PC axons. Rapid synchronization is made possible because ephaptic signals generated by PCs peak during the rising phase of action potentials. These findings show that ephaptic coupling contributes to the prevalent synchronization of nearby PCs.

Activation of Astrocytic μ-opioid Receptor Elicits Fast Glutamate Release Through TREK-1-Containing K2P Channel in Hippocampal Astrocytes

Recently, μ-opioid receptor (MOR), one of the well-known Gi-protein coupled receptors (Gi-GPCR), was reported to be highly expressed in the hippocampal astrocytes. However, the role of astrocytic MOR has not been investigated. Here we report that activation of astrocytic MOR by [D-Ala²,N-MePhe⁴,Gly-ol]-enkephalin (DAMGO), a selective MOR agonist, causes a fast glutamate release using sniffer patch technique. We also found that the DAMGO-induced glutamate release was not observed in the astrocytes from MOR-deficient mice and MOR-short hairpin RNA (shRNA)-expressed astrocytes. In addition, the glutamate release was significantly reduced by gene silencing of the TREK-1-containing two-pore potassium (K2P) channel, which mediates passive conductance in astrocytes. Our findings were consistent with the previous study demonstrating that activation of Gi-GPCR such as cannabinoid receptor CB1 and adenosine receptor A1 causes a glutamate release through TREK-1-containing K2P channel from hippocampal astrocytes. We also demonstrated that MOR and TREK-1 are significantly co-localized in the hippocampal astrocytes. Furthermore, we found that both MOR and TREK-1-containing K2P channels are localized in the same subcellular compartments, soma and processes, of astrocytes. Our study raises a novel possibility that astrocytic MOR may participate in several physiological and pathological actions of opioids, including analgesia and addiction, through astrocytically released glutamate and its signaling pathway.

Management and consequences of postoperative fluctuations in plasma sodium concentration after pediatric brain tumor surgery in the sellar region: a national cohort analysis

PURPOSE

Severe fluctuations in plasma sodium concentration and plasma osmolarity, including central diabetes insipidus (CDI), may have significant influence on postoperative morbidity and mortality after pediatric brain tumor surgery.The aim of this study was to describe the frequency, severity and neurological consequences of these fluctuations in pediatric brain tumor survivors.

METHODS

A retrospective, multi-institutional chart review was conducted among all children who underwent brain tumor surgery in the sellar or suprasellar region in seven university hospitals in the Netherlands between January 2004 and December 2013.

RESULTS

Postoperative CDI was observed in 67.5% of 120 included children. Fluctuations of plasma sodium concentration ≥ 10 mmol/L/24 h during the first ten postoperative days were seen in 75.3% of patients with CDI, with a maximum delta of 46 mmol/L/24 h. When compared to patients without CDI, altered mental status occurred more frequently in patients with postoperative CDI (5.1 vs. 23.5% respectively, p = 0.009). Low plasma sodium concentration was related to altered mental status and the occurrence of seizures. Frequency and severity of fluctuations in plasma sodium concentration during the first ten postoperative days were significantly higher in patients with permanent CDI at last follow-up than in patients with transient CDI or without CDI (p = 0.007).

CONCLUSION

Postoperative CDI is a common complication after pediatric brain tumor surgery in the sellar or suprasellar region. Extreme plasma sodium concentrations and large intra-day fluctuations still occur and seem to influence the postoperative neurological course. These results illustrate the need for intensive monitoring in a highly experienced center.

Expression of µ-Opioid Receptor in CA1 Hippocampal Astrocytes

µ-opioid receptor (MOR) is a class of opioid receptors with a high affinity for enkephalins and beta-endorphin. In hippocampus, activation of MOR is known to enhance the neuronal excitability of pyramidal neurons, which has been mainly attributed to a disinhibition of pyramidal neurons via activating Gαi subunit to suppress the presynaptic release of GABA in hippocampal interneurons. In contrast, the potential role of MOR in hippocampal astrocytes, the most abundant cell type in the brain, has remained unexplored. Here, we determine the cellular and subcellular distribution of MOR in different cell types of the hippocampus by utilizing MOR-mCherry mice and two different antibodies against MOR. Consistent with previous findings, we demonstrate that MOR expression in the CA1 pyramidal layer is co-localized with axon terminals from GABAergic inhibitory neurons but not with soma of pyramidal neurons. More importantly, we demonstrate that MOR is highly expressed in CA1 hippocampal astrocytes. The ultrastructural analysis further demonstrates that the astrocytic MOR is localized in soma and processes, but not in microdomains near synapses. Lastly, we demonstrate that astrocytes in ventral tegmental area and nucleus accumbens also express MOR. Our results provide the unprecedented evidence for the presence of MOR in astrocytes, implicating potential roles of astrocytic MOR in addictive behaviors.

Experience-Dependent Equilibration of AMPAR-Mediated Synaptic Transmission during the Critical Period

Experience-dependent synapse refinement is essential for functional optimization of neural circuits. However, how sensory experience sculpts excitatory synaptic transmission is poorly understood. Here, we show that despite substantial remodeling of synaptic connectivity, AMPAR-mediated synaptic transmission remains at equilibrium during the critical period in the mouse primary visual cortex. The maintenance of this equilibrium requires neurogranin (Ng), a postsynaptic calmodulin-binding protein important for synaptic plasticity. With normal visual experience, loss of Ng decreased AMPAR-positive synapse numbers, prevented AMPAR-silent synapse maturation, and increased spine elimination. Importantly, visual deprivation halted synapse loss caused by loss of Ng, revealing that Ng coordinates experience-dependent AMPAR-silent synapse conversion to AMPAR-active synapses and synapse elimination. Loss of Ng also led to sensitized long-term synaptic depression (LTD) and impaired visually guided behavior. Our synaptic interrogation reveals that experience-dependent coordination of AMPAR-silent synapse conversion and synapse elimination hinges upon Ng-dependent mechanisms for constructive synaptic refinement during the critical period.

Rectal tube drainage reduces major anastomotic leakage after minimally invasive rectal cancer surgery

AIM

Anastomotic leakage is the most serious complication following low anterior resection for rectal cancer and is a major cause of postoperative morbidity and mortality. The object of the present study was to investigate whether rectal tube drainage can reduce anastomotic leakage after minimally invasive rectal cancer surgery.

METHOD

Three hundred and seventy-four patients who underwent laparoscopic or robotic LAR for tumours located ≤ 15 cm above the anal verge between 1 April 2012 and 31 October 2014 were assessed retrospectively. Of these, 107 with intermediate risk of anastomotic leakage received transanal rectal tube drainage. The rectal tube group was matched by propensity score analysis with patients not having rectal tube drainage, giving 204 patients in the study. Covariates for propensity score analysis included age, sex, body mass index, tumour height from the anal verge and preoperative chemoradiation.

RESULTS

Patient demographics, tumour location, preoperative chemoradiation and operative results were similar between the two groups. The overall leakage rate was 10.8% (22/204), with no significant difference between the rectal tube group (9.8%) and the nonrectal tube group (11.8%, P = 0.652). Of the patients with anastomotic leakage, major leakage requiring reoperation developed in 11.8% of those without and 3.9% of those with a rectal tube. On multivariate analysis, age over 65 years and nonuse of a rectal tube were found to be independent risk factors for major anastomotic leakage.

CONCLUSION

Rectal tube placement may be a safe and effective method of reducing the rate of major anastomotic leakage, alleviating the clinical course of leakage following minimally invasive rectal cancer surgery.

Long-term outcomes of locally or radically resected T1 colorectal cancer

AIM

Little is known about the long-term outcome of T1 colorectal cancer (CRC) following curative resection. The present study addressed the long-term outcome of locally or radically resected T1 CRCs.

METHOD

A total of 430 patients with T1 CRC who underwent local or radical resection were considered. Unfavourable histological factors were defined as positive resection margin, deep submucosal invasion, vascular invasion, Grade 3 and budding. The patients were classified as low-risk (unfavourable histological factor negative, n = 65) or high-risk (unfavourable histological factor positive, n = 365).

RESULTS

Over a median follow-up of 78.4 months, disease recurred in 16 (3.7%) patients in the high-risk group, and no recurrence in the low-risk group. Resection type and vascular invasion were significantly associated with recurrence. In the vascular invasion (+) high-risk group, both 5-year disease-free survival rate and 5-year overall survival rate were significantly associated with resection type (radical 94.6%, local 43.8%, P < 0.001, and radical 99.1%, local 66.7%, P < 0.001). In the vascular invasion (-) high-risk group, 5-year disease-free survival rate was also significantly associated with resection type (radical 98.9%, local 84.7%, P = 0.001). However, 5-year overall survival rate was not associated with resection type (radical 98.9%, local 95.2%, P = 0.816).

CONCLUSION

Local resection may be effective and oncologically safe in low-risk T1 CRC. Although additional surgery should be recommended for the locally resected high-risk T1 CRC cases, intensive surveillance without additional surgery and timely salvage operation may offer another treatment option, if vascular invasion is negative.

Ca(2+) Entry is Required for Mechanical Stimulation-induced ATP Release from Astrocyte

Astrocytes and neurons are inseparable partners in the brain. Neurotransmitters released from neurons activate corresponding G protein-coupled receptors (GPCR) expressed in astrocytes, resulting in release of gliotransmitters such as glutamate, D-serine, and ATP. These gliotransmitters in turn influence neuronal excitability and synaptic activities. Among these gliotransmitters, ATP regulates the level of network excitability and is critically involved in sleep homeostasis and astrocytic Ca²⁺ oscillations. ATP is known to be released from astrocytes by Ca²⁺-dependent manner. However, the precise source of Ca²⁺, whether it is Ca²⁺ entry from outside of cell or from the intracellular store, is still not clear yet. Here, we performed sniffer patch to detect ATP release from astrocyte by using various stimulation. We found that ATP was not released from astrocyte when Ca²⁺ was released from intracellular stores by activation of Gα_q-coupled GPCR including PAR1, P2YR, and B2R. More importantly, mechanical stimulation (MS)-induced ATP release from astrocyte was eliminated when external Ca²⁺ was omitted. Our results suggest that Ca²⁺ entry, but not release from intracellular Ca²⁺ store, is critical for MS-induced ATP release from astrocyte.

Channel-mediated astrocytic glutamate modulates hippocampal synaptic plasticity by activating postsynaptic NMDA receptors

Background

Activation of G protein coupled receptor (GPCR) in astrocytes leads to Ca²⁺-dependent glutamate release via Bestrophin 1 (Best1) channel. Whether receptor-mediated glutamate release from astrocytes can regulate synaptic plasticity remains to be fully understood.

Results

We show here that Best1-mediated astrocytic glutamate activates the synaptic N-methyl-D-aspartate receptor (NMDAR) and modulates NMDAR-dependent synaptic plasticity. Our data show that activation of the protease-activated receptor 1 (PAR1) in hippocampal CA1 astrocytes elevates the glutamate concentration at Schaffer collateral-CA1 (SC-CA1) synapses, resulting in activation of GluN2A-containing NMDARs and NMDAR-dependent potentiation of synaptic responses. Furthermore, the threshold for inducing NMDAR-dependent long-term potentiation (LTP) is lowered when astrocytic glutamate release accompanied LTP induction, suggesting that astrocytic glutamate is significant in modulating synaptic plasticity.

Conclusions

Our results provide direct evidence for the physiological importance of channel-mediated astrocytic glutamate in modulating neural circuit functions.

First Report of Choanephora Rot Caused by Choanephora cucurbitarum on Hosta plantaginea in Korea

Hosta plantaginea (Lam.) Asch. is an herbaceous perennial plant with ornamental value. In August 2013, water-soaked spots and wet rot were found on flowers of H. plantaginea in a garden bedded out for landscaping in Hongcheon County, Korea. Symptoms initially appeared as water-soaked spots at the tips of flowers. Dark gray spots on flower petals often coalesced and led to rotting of flowers, with abundant sporulation. However, no symptoms were found on the leaves. Approximately 30% of the flowers were affected in the landscape bed. A fungal isolate was obtained by plating surface-disinfested diseased flower tissue on potato dextrose agar (PDA). Fungal colonies covering the plate (diam. 90 mm) in 48 h were white at first, with abundant aerial mycelia, but later turned pale yellow with abundant sporangiola. Sporangiophores bearing sporangiola were aseptate, hyaline, and usually arose from infected tissue. Sporangiola were ellipsoid to ovoid, indehiscent, brown to dark brown, pediculate, 7 to 12 μm wide and 9 to 20 μm high, and showed longitudinal striations at high magnification. Sporangia were few-spored to multispored, pale brown to brown, and 50 to 150 μm. Sporangiospores from sporangia were broadly ellipsoid, brown to pale brown, with hyaline polar appendages, 8 to 10 μm wide and 15 to 22 μm high. Zygospores were not observed. The morphological and cultural characteristics, especially based on shape and striation of sporangiola, were identical with those of Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. (2,3). A representative specimen was deposited in the Korea University Herbarium (KUS-F27540). Genomic DNA was extracted using a DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA). The primers ITS1/ITS4 and NL1/LR3 were used to amplify the internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU), respectively (4). The PCR products were purified and directly sequenced. The resulting 594-bp ITS and 680-bp D1/D2 sequences were submitted to GenBank (Accession Nos. KM200034 and KM200035). A GenBank BLAST search of the fungal database showed that the sequences of ITS and D1/D2 regions matched those of C. cucurbitrarum (JN943006 and JN939195) with 100% similarity. A pathogenicity test was conducted by spraying three healthy potted plants (2 months old) with a sporangiola suspension (2 × 10⁴ conidia/ml). Another three potted plants of the same age were treated with sterile water and served as controls. The plants were kept in humid chambers for 2 days and placed in a greenhouse (28°C and 60 to 80% RH). After 4 to 5 days, water-soaked spots were evident on the flowers of inoculated plants. No symptoms were observed on control plants. A pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. C. cucurbitarum has a wide host range but has not been previously reported to cause disease on H. plantaginea (1). To our knowledge, this is the first report of C. cucurbitarum on H. plantaginea globally as well as in Korea. Choanephora rot of flowers is an issue under high-moisture conditions, so allowing for adequate airflow and a dry plant canopy should aid in disease suppression. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. Online publication, ARS, USDA, retrieved July 11, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) A. Saroj et al. Plant Dis. 96:293, 2012. (4) G. Walther et al. Persoonia 30:11, 2013.

Glial GABA, synthesized by monoamine oxidase B, mediates tonic inhibition

GABA is the major inhibitory transmitter in the brain and is released not only from a subset of neurons but also from glia. Although neuronal GABA is well known to be synthesized by glutamic acid decarboxylase (GAD), the source of glial GABA is unknown. After estimating the concentration of GABA in Bergmann glia to be around 5-10 mM by immunogold electron microscopy, we demonstrate that GABA production in glia requires MAOB, a key enzyme in the putrescine degradation pathway. In cultured cerebellar glia, both Ca(2+)-induced and tonic GABA release are significantly reduced by both gene silencing of MAOB and the MAOB inhibitor selegiline. In the cerebellum and striatum of adult mice, general gene silencing, knock out of MAOB or selegiline treatment resulted in elimination of tonic GABA currents recorded from granule neurons and medium spiny neurons. Glial-specific rescue of MAOB resulted in complete rescue of tonic GABA currents. Our results identify MAOB as a key synthesizing enzyme of glial GABA, which is released via bestrophin 1 (Best1) channel to mediate tonic inhibition in the brain.

First Report of Choanephora Blight Caused by Choanephora infundibulifera on Hibiscus rosa-sinensis in Korea

Hibiscus rosa-sinensis L., commonly known as Chinese hibiscus, is an evergreen flowering shrub belonging to the Malvaceae and is widely cultivated throughout Asia including Korea. In August 2013, blight was observed on Chinese hibiscus in a commercial flower nursery in Seoul, Korea. Initial symptoms began as reddish purple spots at the tip of flowers and expanded to encompass entire flowers. Infected lesions appeared water-soaked, reddish brown, and were followed by rapid rotting of infected tissues. Approximately 50% of the plants surveyed were affected. Monosporous sporangiola formed on infected tissue were transferred to potato dextrose agar (PDA). Fungal colonies were obtained that were at first white with abundant aerial mycelium, and then became yellowish with the appearance of sporangiola. Sporangiophores bearing sporangiola were erect to slightly curved, unbranched, and hyaline. Funnel-shaped secondary vesicles formed on the primary vesicles. Sporangiola were indehiscent, ovoid to subglobose, smooth, non-striated, brown to dark brown, 10 to 27.5 × 8.5 to 17 μm, and sometimes germinated in culture. The fungus was identified as Choanephora infundibulifera (Curr.) D.D. Cunn. based on the morphological and cultural characteristics (2). Voucher specimens were housed in the Korea University Herbarium (KUS). An isolate obtained from KUS-F27535 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47643) and used for a pathogenicity test and molecular analyses. To confirm identity of the fungus, genomic DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU) were amplified with the primers ITS1/ITS4 and NL1/LR3, respectively (3), and sequenced. The resulting 635-bp ITS and 680-bp D1/D2 sequences were deposited in GenBank (Accession Nos. KF486539 and KF486538). A GenBank BLAST search revealed that the ITS sequences showed 100% similarity with that of C. infundibulifera (JN943009) and D1/D2 sequences also showed 100% identity with that of C. infundibulifera (JN939193). A sporangiola suspension (2 × 10⁴ cells/ml) was sprayed over three pots of the shrub, kept in a humid chamber for 2 days, and placed in greenhouse (28°C and 80 to 100% RH). Another three potted plants of the same age were sprayed with sterile water and served as controls. After 4 days, typical blossom blight symptoms, identical to the ones observed in the nursery, developed on the inoculated flowers. No symptoms were observed on controls. C. infundibulifera was re-isolated from inoculated plants. Pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. Choanephora blight caused by C. infundibulifera on H. rosa-sinenesis has been reported in Japan, Myanmar, Nepal, Guinea, and the United States (1). In Korea, there was one record of this fungus on H. syriacus (1). To our knowledge, this is the first report of C. infundibulifera on H. rosa-sinensis in Korea. This pathogen could be a potential threat to the production of this ornamental shrub over a prolonged period of hot and humid weather. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 28, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) G. Walther et al. Persoonia 30:11, 2013.

First Report of Anthracnose Caused by Colletotrichum lupini on Yellow Lupin in Korea

Yellow lupin (Lupinus luteus L.) is native to the Mediterranean region of southern Europe. In Korea, yellow lupins are cultivated for ornamental purposes. In May 2013, hundreds of yellow lupins that were grown in pots for 7 weeks in polyethylene-film-covered greenhouses were observed severely damaged by a previously unknown disease with about 30% disease incidence in a flower farm in Yongin City, Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Early symptoms on petioles and stems appeared as small, slightly sunken, water-soaked, and circular spots. Lesions increased in size (4 to 12 μm in diameter), became more depressed, with a darkened central portion. As the disease progressed, affected areas sometimes girdled the stem and killed the shoot. Leaves were partly blighted, but less damaged. The darkened areas contained blackish acervuli from which masses of pale salmon-colored conidia were released in moist weather. Acervuli were circular to ellipsoid, 80 to 400 μm in diameter. Acervular setae were not observed. Conidia (n = 30) were long obclavate to oblong-elliptical, aguttulate, hyaline, and 10 to 18 × 3.6 to 5.2 μm with a length/width ratio of 2.6 to 3.6. Appressoria were single or occasionally in small dense clusters, medium brown, elliptical to round in outline with a smooth to lobate margin, and 8 to 14 × 6 to 9 μm. These characters were consistent with the description of Colletotrichum lupini (Bondar) Damm, P.F. Cannon & Crous (1,3). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47254). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 545-bp sequence was deposited in GenBank (Accession No. KJ447119). The sequence showed 100% identity with sequences of C. lupini (e.g., GenBank AJ301968, JN943480, JQ948162, and KF207599). To confirm pathogenicity, inoculum was prepared by harvesting conidia with sterile distilled water from 3-week-old cultures on potato dextrose agar. A conidial suspension (2 × 10⁵ conidia/ml) was sprayed until runoff onto the aerial parts of five healthy plants. Control plants were sprayed with sterile water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 48 h and then transferred to a greenhouse. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. lupini was re-isolated from symptomatic leaf tissues. No symptoms were observed on control plants. The pathogenicity test was repeated twice. Anthracnose associated with C. lupini on lupins has been known from Europe (Germany, Ukraine, Austria, and Netherlands), North America (Canada and the United States), South America (Bolivia and Brazil), and Oceania (Australia and New Zealand) (2,4). To our knowledge, this is the first report of C. lupini on yellow lupins in Asia as well as in Korea. The presence of C. lupini on lupins in Asia can be considered as a potentially new and serious threat to this ornamental plant. References: (1) U. Damm et al. Stud. Mycol. 73:37, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 17, 2014. (3) H. I. Nirenberg et al. Mycologia 94:307, 2002. (4) E. Rosskopf et al. Plant Dis. 98:161, 2014.

First Report of White Blister Rust Caused by Albugo candida on Wasabi in Korea

Wasabi (Wasabia japonica (Miq.) Matsum.), a member of the Brassicaceae family, is a commercially important crop in East Asian countries such as China, Japan, Korea, and Taiwan. In Korea, wasabi is under commercial development since it has become popular as a condiment due to its strong pungent constituents. In May 2013, wasabi plants showing typical symptoms of white blister rust disease were first observed in plastic greenhouses in Taebaek City, Korea. Leaves of infected plants had whitish sori on the lower surfaces and chlorotic blotches on the corresponding upper leaf surfaces. Later, sori changed to creamy to light tan with necrosis of leaf lesion. New infections might occur anytime during the growing season. A representative sample was deposited in the Korea University Herbarium (KUS-F27596). Microscopic examination of fresh materials was performed under a light microscope. The grouped sporangiophores were hyaline, clavate or cylindric, and measured 20 to 35 × 10 to 14 μm. The sporangia were arranged in basipetal chains, hyaline, globose to subglobose, with uniform wall thickness and measured 16 to 21 × 13 to 18 μm. The primary sporangia were morphologically similar to the secondary sporangia, although the former exhibited a slightly thicker wall than the latter. No resting organs were observed. Previously, the white blister rust pathogen on wasabi has been considered either Albugo candida or A. wasabiae, although the latter name is often considered a synonym of A. candida. Based on the morphological characteristics and the specific host plant, the causal agent of this disease was identified as A. candida (2). To confirm this morphological identification, genomic DNA was extracted from infected plant tissue, and the amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1), with oomycete-specific primer set, DC6 and LR0. The resulting 835-bp sequence of the region was deposited in GenBank (Accession No. KF887494). Since this was the first ITS sequence submitted for A. candida on wasabi, comparable data were not available. A comparison with the ITS sequences available in the GenBank database revealed that it is identical to A. candida found on Capsella bursa-pastoris (AF271231), and shows a high similarity of 99% with many A. candida sequences originating from other brassicaceous plants. Therefore, the pathogen found in Korea was confirmed to be A. candida. In Korea, it has been reported that A. candida attacks Brassica juncea, B. campestris subsp. penikensis, and B. napus (3), but to our knowledge this is the first record of A. candida on wasabi (4). The white blister rust caused by A. candida is one of the most devastating diseases of wasabi in Japan and Taiwan where the crop is widely cultivated. On the other hand, in the United States, Canada, and New Zealand, where wasabi is a new crop on a commercial scale, there is no record of this disease. These facts taken together suggest that wasabi white blister rust be not only currently spreading in East Asia, but it also poses a new and serious threat to production of this crop in countries in which it is currently absent. References: (1) Y. J. Choi et al. Mol. Phylogenet. Evol. 40:400, 2006. (2) Y. J. Choi et al. Fungal Divers. 27:11, 2007. (3) Y. J. Choi et al. Plant Pathol. J. 27: 192, 2011. (4) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 15, 2013.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Chervil in Korea

Chervil (Anthriscus cerefolium (L.) Hoffm.), belonging to the family Apiaceae, is an aromatic annual herb that is native to the Caucasus. It is widely used as a flavoring agent for culinary purposes. This herb was recently introduced in Korea. In April 2013, plants showing typical symptoms of powdery mildew disease were observed in a polyethylene film-covered greenhouse in Seoul, Korea. White mycelium bearing conidia formed irregular patches on leaves and stems. Mycelial growth was amphigenous. Severe infections caused leaf withering and premature senescence. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were septate, branched, with moderately lobed appressoria. Conidiophores presented 3 to 4 cells and measured 85 to 148 × 7 to 9 μm. Foot-cells of conidiophores were 37 to 50 μm long. Conidia were produced singly, oblong-elliptical to oblong, measured 30 to 50 × 13 to 18 μm with a length/width ratio of 2.0 to 3.3, lacked conspicuous fibrosin bodies, and with angular/rectangular wrinkling of the outer walls. Germ tubes were produced in the subterminal position of conidia. Chasmothecia were not found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and morphological characteristics were consistent with those of E. heraclei DC. (1). To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F27279 was amplified with primers ITS5 and P3 (4) and sequenced directly. The resulting 561-bp sequence was deposited in GenBank (Accession No. KF111807). A GenBank BLAST search of this sequence showed >99% similarity with those of many E. heraclei isolates, e.g., Pimpinella affinis (AB104513), Anethum graveolens (JN603995), and Daucus carota (EU371725). Pathogenicity was confirmed through inoculation by gently pressing a diseased leaf onto leaves of five healthy potted chervil plants. Five non-inoculated plants served as a control treatment. Plants were maintained in a greenhouse at 22 ± 2°C. Inoculated plants developed signs and symptoms after 6 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Chervil powdery mildews caused by E. heraclei have been reported in Europe (Bulgaria, France, Germany, Hungary, Italy, Romania, Switzerland, and the former Soviet Union) and the United States (2,3). To our knowledge, this is the first report of powdery mildew caused by E. heraclei on chervil in Asia as well as in Korea. The plant is cultivated in commercial farms for its edible leaves in Korea. Occurrence of powdery mildew is a threat to quality and marketability of this herb, especially those grown in organic farming where chemical control options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved July 29, 2013. (3) S. T. Koike and G. S. Saenz. Plant Dis. 88:1163, 2004. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

High glutamate permeability and distal localization of Best1 channel in CA1 hippocampal astrocyte

Background

Glutamate is the major neurotransmitter that mediates a principal form of excitatory synaptic transmission in the brain. From the presynaptic terminals of neurons, glutamate is released upon exocytosis of the glutamate-packaged vesicles. In recent years, astrocytes are also known to release glutamate via various routes to modulate synaptic transmission. In particular, we have characterized a glutamate-permeable Ca²⁺-activated anion channel encoded by Bestrophin 1 gene (Best1) that is responsible for Ca²⁺-dependent, channel-mediated glutamate release in astrocyte. Best1 channel contains a large pore that is readily permeable to large molecules such as glutamate and GABA. In those studies we obtained permeability ratio of glutamate to Cl^- in heterologously expressed mouse Best1 in HEK293T cells and in endogenously expressed mouse Best1 in cultured astrocytes. However, up to now, glutamate permeability of the native Best1 channel in vivo has not been reported.

Findings

In whole-cell recordings of CA1 hippocampal astrocytes, we found that opening of Best1 channel upon activation of a Gq-coupled GPCR, protease-activated receptor 1 (PAR1) generated the anion current carried by glutamate via Ca²⁺ increase. This Ca²⁺-evoked glutamate-mediated anion current was unaffected by pretreatment of the inhibitors for a gap junction hemi-channel or Ca²⁺-activated K⁺ conductance. This astrocytic anion conductance carried by glutamate was mediated by Best1 channel expression in CA1 hippocampal astrocytes, because Best1 knock-down by shRNA expression eliminated astrocytic glutamate conductance by PAR-1 activation. However, we found that these astrocytes showed a deviation in reversal potential of Best1-mediated current from the predicted value. By performing dual patch recording, we concluded that the deviation of reversal potential is due to incomplete space clamping arising from extremely leaky membrane (input resistance ranging 1–3 MΩ), very low length constant of astrocytic processes, and the localization of Best1 channel in distal microdomains near synapses. Based on the relative shift of reversal potentials by ion substitutions, we estimated the permeability ratio of glutamate and Cl^- (P_glutamate/P_Cl) as 0.53.

Conclusions

Our study shows that Best1, located at the microdomains near the synaptic junctions, has a significantly high permeability to glutamate in vivo, serving as the prominent glutamate-releasing channel in astrocytes, mediating the release of various gliotransmitters in the brain, and playing an important role in modulating synaptic transmission.

First Report of Anthracnose Caused by Colletotrichum sansevieriae on Sansevieria in Korea

Sansevieria, Sansevieria trifasciata Prain, is cultivated in greenhouses and is used as a potted interior foliage plant in Korea. In April 2012, several plants (cv. Moonshine) exhibiting typical anthracnose symptoms from a local nursery were sent to the plant clinic of Gyeonggi-Do Agricultural Research and Extension Services for diagnosis. The leaf lesions began as round, partly water-soaked, pale greenish to grayish spots, which enlarged and ultimately coalesced, resulting in severe leaf blight. Concentric rings of blackish acervuli were formed in the expanding lesions of mostly 2 to 4 cm in diameter. Acervuli were mostly epiphyllous, circular to ellipsoid. Setae were aseptate to 3-septate, dark brown at the base, paler upwards, acicular, and up to 180 μm long. Conidia (n = 30) were oblong-elliptical to obovate, sometimes fusiform-elliptical, guttulate, hyaline, and 14 to 24 × 5 to 7.5 μm (mean 18.6 × 6.4 μm). Hyphopodial appressoria were dark brown to blackish, globose to clavate in outline, and 5 to 12 × 4 to 8 μm. Colonies on potato dextrose agar (PDA) were grayish-white, felted with cottony-white aerial mycelium on a gray to olivaceous gray background in culture. Gelatinous salmon- to orange-colored conidial masses were produced abundantly after one week's incubation. The morphological and cultural characteristics of the fungus were consistent with the description of Colletotrichum sansevieriae M. Nakamura & M. Ohzono (2,3). A voucher specimen was deposited in the Korea University herbarium (KUS-F26637). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46835). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 569-bp sequences were deposited in GenBank (Accession No. KC847065). A BLAST search in GenBank exhibited 100% nucleotide identity with sequence of C. sansevieriae (JF911349) from the United States and >99% similarity with that of HQ433226 from Australia. To confirm pathogenicity, inoculum was prepared by harvesting conidia from 3-week-old cultures on PDA. A conidial suspension (2 × 10⁶ conidia/ml) was sprayed over the five leaves of sansevieria 'Moonshine' wounded with a fine needle. Five leaves sprayed with sterile water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 48 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). Within 12 days, symptoms identical to those observed in originally infected leaf developed on all inoculated leaves. No symptoms were observed on control plants. C. sansevieriae was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Sansevieria anthracnose associated with C. sansevieriae has been reported in Japan (2), Australia (1), and the United States (3). To our knowledge, this is the first report of sansevieria anthracnose in Korea. Our observations in sansevieria nurseries suggest that preventing wound infection as well as maintaining good plant hygiene in greenhouses might be main strategies for this disease. References: (1) R. Aldaoud et al. Australas. Plant Dis. Notes 6:60, 2011. (2) M. Nakamura et al. J. Gen. Plant Pathol. 72:253, 2006. (3) A. J. Palmateer et al. Plant Dis. 96:293, 2012.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Papaya in Korea

In March 2013, papaya (Carica papaya L. cv. Sunrise) plants growing in polyethylene-film-covered greenhouses in Agricultural Research Center for Climate Change located in Jeju City, Korea, were observed severely affected by a powdery mildew. Symptoms appeared as circular to irregular white patches on both sides of the leaves. As the disease progressed, the plants were covered with dense masses of the spores, eventually causing senescence and withering of leaves. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were flexuous to straight, branched, septate, and 5 to 8 μm wide. Conidiophores were 110 to 250 × 10 to 12.5 μm and produced 2 to 5 immature conidia in chains with a crenate outline followed by 2 to 3 cells. Foot-cells of conidiophores were straight, cylindric, slightly constricted at the basal septum, and 55 to 110 μm long. Conidia were hyaline, ellipsoid-ovoid, measured 22 to 38 × 18 to 21 μm with a length/width ratio of 1.2 to 1.8, and had distinct fibrosin bodies. Chasmothecia were scattered or partly clustered, dark brown, spherical, 80 to 100 μm in diameter, and each contained a single ascus. Appendages were mycelioid, 1- to 5-septate, brown at the base and becoming paler. Asci were sessile, 72 to 87 × 52 to 68 μm, had a terminal oculus of 17 to 23 μm wide, and contained 8 ascospores, each 17 to 23 × 12.5 to 15 μm. The morphological characteristics and measurements were consistent with those of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F27269 was amplified with the primers ITS5/P3 and sequenced (3). The resulting 443 bp sequence was deposited in GenBank (Accession No. KF111806). The Korean isolate showed >99% similarity with those of many P. xanthii isolates including an isolate on papaya from Taiwan (GU358450). Pathogenicity was confirmed through inoculation tests by gently pressing a diseased leaf onto young leaves of three asymptomatic, potted seedlings (cv. Sunrise). Three non-inoculated seedlings were used as control. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 26 to 30°C. Inoculated leaves developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was identical morphologically to that observed on the original diseased leaves, fulfilling Koch's postulates. Powdery mildews of papaya caused by Podosphaera species including P. caricae-papayae have been reported in North America, South America, Hawaii, Africa, Ukraine, Australia, New Zealand, the Cook Islands, India, Thailand, Taiwan, and Japan (2,4). P. caricae-papayae is currently reduced to synonymy with P. xanthii (1). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on papaya in Korea. Though papaya is a minor crop in Korea, producing about 300 M/T annually in greenhouses, powdery mildew disease is a threat to safe production of the fruits. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved April 9, 2013. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) J. G. Tsay et al. Plant Dis. 95:1188, 2011.

Treatment of neonatal progressive ventricular dilatation: a single-centre experience

OBJECTIVE

To describe our experience with a cohort of 295 infants with progressive ventricular dilatation occurring in the antenatal or neonatal period.

METHODS

A search was performed in our cranial ultrasound database. All records and images of infants in whom an imaging diagnosis of progressive ventricular dilatation had been made were retrieved. In addition, modes of treatment were analysed.

RESULTS

Between February 1991 and March 2012, 295 neonates were admitted to our level 3 neonatal intensive care unit (NICU), and developed progressive ventricular dilatation for which they required intervention. In the majority of these infants, progressive ventricular dilatation developed following IVH grade III or IV (240/295; 81%) of whom 214/240 (89%) were preterms. Temporary treatment with lumbar punctures and punctures from ventricular reservoirs was sufficient for the majority of the preterms. A ventricular reservoir was inserted in 216/295 infants (73%). The overall infection rate was low (6%). A ventriculoperitoneal shunt (VP shunt) was inserted in 32% of the whole cohort, revision within 3 months was necessary in 20%, and shunt-related infection occurred in 12%.

CONCLUSIONS

This large, single-centre cohort study reports the management of progressive ventricular dilatation in newborn infants. We have shown that with our approach, complications stay within acceptable limits.

First Report of Sclerotinia Stem Rot of Anemone Caused by Sclerotinia sclerotiorum in Korea

In Korea, anemones (Anemone coronaria L.) are mostly grown during winter, in polyethylene tunnels that may have high humidity and poor ventilation, to meet the high demand of cut flowers in February and March for school ceremonies. During the winter of 2011 to 2012, symptoms typical of Sclerotinia stem rot were observed in commercial crops of anemone (cv. Rosso Mistral Plus) in Hwaseong City, Korea. About 40% of anemones withered or died before harvest due to the disease, causing considerable economic losses. In one farmer's polyethylene tunnel with a good ventilation system in Icheon City, Korea, less than 1% of the anemones showed Sclerotinia stem rot during the same season. Symptoms included stem necrosis and withering of leaves, followed by crown rot and wilt a few days afterward. White cottony growth of the fungus was observed on dead plants and the nearby soil surface, especially under high relative humidity. Black sclerotia 2 to 7 mm in diameter developed in the mycelium. Isolations from surface-disinfested stem pieces onto potato dextrose agar (PDA) consistently yielded white, fluffy colonies. Two-week-old colonies produced plentiful numbers of sclerotia on PDA. The isolated fungus was morphologically identified as Sclerotinia sclerotiorum (Lib.) de Bary (1,3). Voucher specimens (n = 4) were deposited in the Korea University herbarium (KUS). Two isolates were deposited in the Korean Agricultural Culture Collection with accession numbers KACC46708 (ex KUS-F26433) and KACC46834 (ex KUS-F26437), respectively. Fungal DNA was extracted with a DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 (4) and sequenced using an ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequences of 501 bp were deposited in GenBank (Accession Nos. KC412065 and KC412066). A BLAST search revealed that sequences of the two Korean isolates showed 100% identity with those of S. sclerotiorum (e.g., GenBank Accession No. JN012606). A pathogenicity test was achieved by placing agar segments (9 mm²) from a 7-day-old culture grown on PDA on the stems of healthy anemones (cv. Rosso Mistral Plus) near the soil line. Three plants inoculated with agar blocks served as controls. Plants were maintained in a greenhouse at 16 to 20°C and relative humidity >90%. After 2 days, all inoculated stems became discolored, soft, watery, and covered with white mycelia, whereas control plants remained symptomless. S. sclerotiorum was consistently reisolated from the symptomatic tissue, fulfilling Koch's postulates. Sclerotinia stem rot of anemones caused by S. sclerotiorum has previously been recorded from the United States and New Zealand (2), and to our knowledge, this is the first report of S. sclerotiorum on anemone in Korea. According to our observations in damaged plots, low temperature, high humidity, poor ventilation, and continuous cultivation would accelerate the incidence of Sclerotinia stem rot in polyethylene tunnel cultivation systems in Korea. References: (1) M. D. Bolton et al. Mol. Plant Pathol. 7:1, 2006. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA. Retrieved December 3, 2012. (3) S. Umemoto et al. J. Gen. Plant Pathol. 73:290, 2007. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

First Report of Sclerotinia Stem Rot of Anemone Caused by Sclerotinia sclerotiorum in Korea

In Korea, anemones (Anemone coronaria L.) are mostly grown during winter, in polyethylene tunnels that may have high humidity and poor ventilation, to meet the high demand of cut flowers in February and March for school ceremonies. During the winter of 2011 to 2012, symptoms typical of Sclerotinia stem rot were observed in commercial crops of anemone (cv. Rosso Mistral Plus) in Hwaseong City, Korea. About 40% of anemones withered or died before harvest due to the disease, causing considerable economic losses. In one farmer's polyethylene tunnel with a good ventilation system in Icheon City, Korea, less than 1% of the anemones showed Sclerotinia stem rot during the same season. Symptoms included stem necrosis and withering of leaves, followed by crown rot and wilt a few days afterward. White cottony growth of the fungus was observed on dead plants and the nearby soil surface, especially under high relative humidity. Black sclerotia 2 to 7 mm in diameter developed in the mycelium. Isolations from surface-disinfested stem pieces onto potato dextrose agar (PDA) consistently yielded white, fluffy colonies. Two-week-old colonies produced plentiful numbers of sclerotia on PDA. The isolated fungus was morphologically identified as Sclerotinia sclerotiorum (Lib.) de Bary (1,3). Voucher specimens (n = 4) were deposited in the Korea University herbarium (KUS). Two isolates were deposited in the Korean Agricultural Culture Collection with accession numbers KACC46708 (ex KUS-F26433) and KACC46834 (ex KUS-F26437), respectively. Fungal DNA was extracted with a DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 (4) and sequenced using an ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequences of 501 bp were deposited in GenBank (Accession Nos. KC412065 and KC412066). A BLAST search revealed that sequences of the two Korean isolates showed 100% identity with those of S. sclerotiorum (e.g., GenBank Accession No. JN012606). A pathogenicity test was achieved by placing agar segments (9 mm²) from a 7-day-old culture grown on PDA on the stems of healthy anemones (cv. Rosso Mistral Plus) near the soil line. Three plants inoculated with agar blocks served as controls. Plants were maintained in a greenhouse at 16 to 20°C and relative humidity >90%. After 2 days, all inoculated stems became discolored, soft, watery, and covered with white mycelia, whereas control plants remained symptomless. S. sclerotiorum was consistently reisolated from the symptomatic tissue, fulfilling Koch's postulates. Sclerotinia stem rot of anemones caused by S. sclerotiorum has previously been recorded from the United States and New Zealand (2), and to our knowledge, this is the first report of S. sclerotiorum on anemone in Korea. According to our observations in damaged plots, low temperature, high humidity, poor ventilation, and continuous cultivation would accelerate the incidence of Sclerotinia stem rot in polyethylene tunnel cultivation systems in Korea. References: (1) M. D. Bolton et al. Mol. Plant Pathol. 7:1, 2006. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA. Retrieved December 3, 2012. (3) S. Umemoto et al. J. Gen. Plant Pathol. 73:290, 2007. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

First Report of Black Stem Caused by Botryosporium longibrachiatum on Sweet Basil in Korea

Sweet basil, Ocimum basilicum L., is cultivated mainly for fresh consumption in Korea. In March 2009, in Icheon, Korea, several dozen plants showing symptoms of black stems were found in an organic farm that used polyethylene tunnels for production. The black stems were usually covered with a fungus that gave the appearance of hoar-frost on the stems, especially when plants were grown under a cool and humid environment. According to the farmer, black stems appear during the winter season of November to March when the tunnels were mostly closed. The relative humidity (RH) during that period was around 100% every night due to poor ventilation. Beginning the middle of April when both sides of the tunnels were open, providing good ventilation, no further disease development was observed. The fungus on the stems had an elongate, upright conidiophore, reaching 5 mm in length. At intervals along its length, the main axis of conidiophores produced lateral fertile branches in acropetal succession. Each lateral branch terminated in a cluster of four or five ampullae. Conidia were hyaline, oval, and 5.5 to 9.5 × 3.5 to 6 μm. The fungus was non-pigmented and colonies on potato dextrose agar were chalk white. Morphological and cultural characteristics of the fungus were consistent with the previous reports of Botryosporium longibrachiatum (Oudem.) Maire (3,4). Voucher specimens (n = 4) were housed at Korea University Herbarium (KUS). An isolate from KUS-F24010 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC44849) and used for molecular analysis and pathogenicity tests. The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 592 bp was deposited in GenBank (Accession No. JX666334). A BLAST search in GenBank showed that there was no comparable sequence of B. longibrachiatum and thus this was the first ITS sequence for the species submitted in GenBank. To confirm the pathogenicity, colonized mycelial plugs (3 mm in diameter) from 10-day-old PDA cultures were placed onto the stem apices (n = 10) of 2-month-old sweet basil pot plants, which were topped as normally harvested. Control plants were inoculated with uncolonized agar plugs. All plants were incubated at 22 ± 2°C in a humidified chamber with a 12-h photoperiod for 48 h, and then maintained in a greenhouse (22 ± 2°C). Three to four days after inoculation, necrotic lesions developed around the points of inoculation on all stems and expanded downwards, leading to black stems covered with the hoar-frost like fungus after 14 days. B. longibrachiatum was successfully reisolated from all inoculated stems, while control plants remained symptomless. The pathogenicity test was conducted twice with the same result. The association of B. longibrachiatum and sweet basil was previously reported (4). Several other plants including burley tobacco are also reported to be infected by this fungus (1,2). To our knowledge, this is the first etiological report of B. longibrachiatum on sweet basil globally as well as in Korea. References: (1) T. R. Anderson. Plant Dis. 67:1158, 1983. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 7, 2012. (3) C. V. Subramanian. Hyphomycetes. Indian Council of Agricultural Research, New Delhi, India, 1971. (4) H. T. Tribe and R. W. S. Weber. Mycologist 15:158, 2001.

Clinicopathological characteristics of T1 colorectal cancer without background adenoma

AIM

Background adenoma (BGA) is defined as benign adenomatous tissue contiguous to resected carcinomas, and the absence of BGA in a tumour is considered a histological criterion of de novo cancers. The present study aimed to identify the clinicopathological characteristics of T1 colorectal cancer (CRC) without BGA.

METHOD

A retrospective review was carried out of prospectively collected data from two centres: the National Cancer Center, Korea; and Chonnam National University Hwasun Hospital, Korea. A total of 590 patients with T1 CRC, treated by endoscopic or surgical resection between January 2001 and August 2011, were enrolled. Details regarding gender, age, tumour location, endoscopic gross type, tumour size, depth of submucosal (SM) invasion, angiolymphatic invasion, tumour grade, budding and lymph node (LN) metastasis were evaluated with regard to the presence or absence of BGA.

RESULTS

BGA was absent in 197 (33.4%) patients. Tumour size <20 mm, flat or depressed type, deep SM depth and tumour budding were associated with the absence of BGA in univariate and multivariate analyses (P < 0.05). In surgically resected patients, LN metastases were significantly associated with the absence of BGA (P = 0.022).

CONCLUSION

T1 CRC without BGA presented several characteristics of small size (<20 mm), flat or depressed type, deep SM depth (SM 2/3), LN metastasis and tumour budding. These results indicate that de novo cancers may have a more invasive potential.

First Confirmed Report of Cercospora Blight of Asparagus Caused by Cercospora asparagi in Korea

In September 2011, hundreds of asparagus (Asparagus officinalis L.) showing symptoms of blight with nearly 100% incidence (percentage of plants affected) were found in polyethylene tunnels at an organic farm in Gangneung City of Korea. Lesions on needles and branches of the ferns were small, elliptic to subcircular, pale tan to brown with reddish brown borders, and became gray and cottony due to heavy sporulation under continuous high humidity. Infection caused premature defoliation and weakened plant vigor. The damage purportedly due to this disease has reappeared with confirmation of the causal agent made again in 2012. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were well developed, consisting of brown cells, and were 10 to 30 μm wide. Conidiophores were fasciculate (n = 2 to 12), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones, or 1 to 2 times geniculate in longer ones, 40 to 260 μm long, 3.5 to 5.5 μm wide, and 1- to 6-septate. Conidia were hyaline, cylindric to acicular, straight in shorter ones, curved in longer ones, truncate to obconically truncate at the base with darkened hila, guttulate, 2- to 12-septate, and 40 to 220 × 3 to 5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora asparagi Sacc. (1). Voucher specimens were housed at the Korea University herbarium (KUS). An isolate from KUS-F26046 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46400). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 497 bp was deposited in GenBank (Accession No. JX964995). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. For pathogenicity tests, conidial suspensions (10⁵ conidia/ml) were prepared by culturing the fungus on V8 juice agar (2) for 3 weeks. Five plants were inoculated with conidial suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain 100% RH for 24 h and then transferred to a greenhouse. Typical symptoms of necrotic lesions appeared on the inoculated plants 6 days after treatment, and were identical to the ones observed in the field. C. asparagi was reisolated from symptomatic tissues, confirming Koch's postulates. No symptoms were observed on control plants. The disease has been reported through the regions of the world where asparagus is grown (3). In Korea, the disease was recorded in 1928 by Japanese workers under Cercosporina asparagicola Speg. (regarded as synonymous with Cercospora asparagi) with brief notes (4). Though one sample of asparagus was sent to the author (KSH) for diagnosis in 2009 summer and determined to be infected with C. asparagi (unpublished data), there has been no additional finding of the disease in Korea for the last 82 years. To our knowledge, this is the first confirmed report of Cercospora blight of asparagus caused by C. asparagi in Korea. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) C. J. Cooperman and S. F. Jenkins. Phytopathology 76:617, 1986. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved October 20, 2012. (4) K. Nakata and S. Takimoto. Bull. Agric. Exp. Stat. Korea 15:1, 1928.

First Report of Persian Buttercup Downy Mildew Caused by Peronospora sp. in Korea

Persian buttercup (Ranunculus asiaticus L.) is an ornamental plant cultivated mainly in the countries surrounding the Mediterranean Sea, and has recently become popular in Korea. During March and April 2012, Persian buttercups 'Elegance' showing symptoms of downy mildew were found in plastic greenhouses in Hwaseong City of Korea. Infection resulted in chlorotic leaves with a dark greyish and dense fungal-like growth on the lower surfaces, and finally led to necrosis of the lesions. A sample was deposited in the Korea University herbarium (KUS-F26431). Conidiophores emerging from stomata were hyaline, 250 to 550 × 7 to 15 μm, straight, and dichotomously branched in 6 to 8 orders. Ultimate branchlets were mostly in pairs, slightly curved, 5 to 15 μm long, and had obtuse tips. Conidia were brown, broadly ellipsoidal to subglobose or ellipsoidal, often pedicellated, and measured 24 to 33 × 20 to 27 μm with a length/width ratio of 1.15 to 1.30. Fourteen species of Peronospora have previously been described on the genus Ranunculus (2), of which P. ficariae was mostly considered the causal agent of downy mildew on Persian buttercup (1,3). The present Korean accession is morphologically distinct from P. ficariae on R. ficaria (a synonym of Ficaria verna) by somewhat larger conidia with often pedicel-like ends. The nuclear ribosomal LSU and ITS regions were PCR-amplified and sequenced as described in Göker et al. (4), and the resulting sequences deposited in GenBank (Accession Nos. KC111207 and JX465737, respectively). A comparison with the GenBank sequences revealed that the present Korean pathogen differed from P. ficariae on R. ficaria at 10 of 688 characters (about 1.5%) in LSU (AF119600) and 11 of 802 characters (about 1.4%) in ITS sequences (unpublished sequence). In addition, the ITS sequence exhibits a dissimilarity of 1.5 to 2.0% from three species of Peronospora parasitic on Ranunculus; P. alpicola on R. aconitifolius (AY198271), P. illyrica on R. illyricus (AY198268), and P. ranunculi on R. acris (AY198267) and R. recurvatus (AY198269). Based on morphological and molecular distinction between P. ficariae and the Korean pathogen, we provisionally indicate this pathogen as an undetermined species of Peronospora. Pathogenicity was demonstrated by shaking diseased leaves onto the leaves of healthy Persian buttercup 'Elegance', incubating the plants in a dew chamber at 20°C for 24 h, and then maintaining them in a greenhouse (20 to 24°C and relative humidity 60 to 80%). After 3 to 4 days, inoculated plants developed downy mildew symptoms, from which an identical fungus was observed, thus fulfilling Koch's postulates. Control plants treated with sterile water did not develop any symptoms of downy mildew. To our knowledge, this is the first report of a downy mildew on Persian buttercup in Asia, although this disease has been found in other continental countries, such as Italy (1), New Zealand, South Africa, and the United States (3). The presence of a downy mildew on Persian buttercup in Asia can be considered as a potentially new and serious threat to commercial production of this ornamental plant. References: (1) E. Buonocore and R. Areddia. Informatore Fitopatologico 49:25, 1999. (2) O. Constantinescu. Thunbergia 15:1, 1991. (3) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved August 4, 2012. (4) M. Göker et al. Mycol. Res. 113:308, 2009.

Recovery of intact IgG in the gastrointestinal tract of the growing rat following ingestion of an ovine serum immunoglobulin

The aim of this study was to determine whether orally ingested ovine serum IgG partly resists digestion in the growing rat. Fifteen Sprague-Dawley male rats were allocated to one of three diets for a 3-week study: a control diet (CON) and two test diets containing either freeze-dried ovine serum immunoglobulin (FDOI) or inactivated ovine serum immunoglobulin (IOI). Samples of stomach chyme and intestinal digesta from the ad libitum-fed rats were subjected to ELISA and Western blot analysis. Amounts of intact ovine IgG for the FDOI diet were found to be 13.9, 20.0, 34.1, 13.0 and 36.9 μg in the total wet digesta from the stomach chyme, duodenal, jejunal, ileal and colonic digesta respectively. Qualitative detection by Western blot revealed the presence of intact ovine serum IgG with a ~150 kDa MW. This was detected in all of the gut segments (stomach chyme, duodenal, jejunal, ileal and colonic digesta) for growing rats fed the FDOI diet. No ovine IgG was detected in the chyme or digesta from rats fed the CON or the IOI diets. Ovine serum IgG partly resisted digestion in the growing rat fed the FDOI diet and was found throughout the digestive tract. These results provide a basis to explain the reported biological effects of orally administered immunoglobulin.

First Report of Frosty Mildew Caused by Mycopappus alni on Asian Pear in Korea

Asian pear (Pyrus pyrifolia Nakai), also known as Japanese or Korean pear, is widely cultivated in East Asia. On September 2011, irregularly shaped necrotic lesions were observed on leaves of cv. Shinheung growing in an orchard in Gangneung City, Korea. At 40× magnification under a microscope, the white to cream colored propagules were epiphyllous, conical, scattered to aggregated, and composed of stroma-like bases, globose to subglobose, 55 to 100 μm wide and 35 to 75 μm high with filamentous and claviform hyphae. The filamentous hyphae were cylindrical, 125 to 425 × 3.5 to 6 μm, 2- to 8-septate, and obtuse to subobtuse at the apex. The claviform hyphae were clavate to cylindrical, 35 to 125 × 5 to 12.5 μm, aseptate to 3-septate, and obtuse at the apex. The fungus was isolated from leaf lesions and cultured on potato dextrose agar (PDA). The colonies consisted of thin mycelia colored whitish at first and then pale brown on PDA. Sclerotia were produced on PDA after 2 weeks incubation at 15°C, but conidia were not observed in culture. An isolate from KUS-F26196 was deposited in the Korean Agricultural Culture Collection (Accession No. 25 KACC46693). These morphological and cultural characteristics were consistent with Mycopappus alni (Dearn. & Barthol.) Redhead & G.P. White (1,3,4). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence product of 520 bp was deposited in GenBank (Accession No. JX458815). A BLAST search in GenBank revealed that the sequence was 99% similar to M. alni (AB254190, AB254177, AB254189). To determine the pathogenicity of the fungus, propagules were detached from lesions on the naturally infected leaves using fine needles. Each propagule was transferred individually onto five places of six detached healthy leaves. Control treatment comprised placing small agar blocks onto five places of six detached healthy leaves. The plants were incubated in a humid chamber at RH 100% and 18°C. Symptoms were observed after 2 days on all inoculated leaves. The pathogen was reisolated from lesions on the inoculated leaves, confirming Koch's postulates. No symptoms were observed on control leaves. The fungus has been associated with frosty mildew on Alnus spp., Betula spp., Crataegus spp., and Pyrus spp. in North America, Turkey, Russia, and Japan (1,2,4). To our knowledge, this is the first report of frosty mildew on P. pyrifolia caused by M. alni globally as well as in Korea. Since the infections may be limited to the mountainous area with low night temperature and high humidity, economic losses seem to be negligible. However, the disease could be a potential threat to the safe production of Korean pears in case of prolonged period of cool and moist weather. References: (1) U. Braun et al. Mikologiya i Fitopatologiya 34(6):1, 2000. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , August 2, 2012. (3) S. A. Redhead and G. P. White. Can. J. Bot. 63:1429, 1985. (4) Y. Takahashi et al. Mycoscience 47:388, 2006.

First Report of Leaf Blight Caused by Septoria allii on Garlic Chives in Korea

Garlic chives, Allium tuberosum Roth., are widely cultivated in Asia and are the fourth most important Allium crop in Korea. In June 2011, a leaf blight of garlic chives associated with a Septoria spp. was observed on an organic farm in Hongcheon County, Korea. Similar symptoms were also found in fields within Samcheok City and Yangku County of Korea during the 2011 and 2012 seasons. Disease incidence (percentage of plants affected) was 5 to 10% in organic farms surveyed. Diseased voucher specimens (n = 5) were deposited at the Korea University Herbarium (KUS). The disease first appeared as yellowish specks on leaves, expanding to cause a leaf tip dieback. Half of the leaves may be diseased within a week, especially during wet weather. Pycnidia were directly observed in leaf lesions. Pycnidia were amphigenous, but mostly epigenous, scattered, dark brown to rusty brown, globose, embedded in host tissue or partly erumpent, separate, unilocular, 50 to 150 μm in diameter, with ostioles of 20 to 40 μm in diameter. Conidia were acicular, straight to sub-straight, truncate at the base, obtuse at the apex, hyaline, aguttulate, 22 to 44 × 1.8 to 3 μm, mostly 3-septate, occasionally 1- or 2-septate. These morphological characteristics matched those of Septoria allii Moesz, which is differentiated from S. alliacea on conidial dimensions (50 to 60 μm long) (1,2). A monoconidial isolate was cultured on potato dextrose agar (PDA). Two isolates have been deposited in the Korean Agricultural Culture Collection (Accession Nos. KACC46119 and 46688). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 482-bp was deposited in GenBank (JX531648 and JX531649). ITS sequence information was at least 99% similar to those of many Septoria species, however no information was available for S. allii. Pathogenicity was tested by spraying leaves of three potted young plants with a conidial suspension (2 × 10⁵ conidia/ml), which was harvested from a 4-week-old culture on PDA. Control leaves were sprayed with sterile water. The plants were placed in humid chambers (relative humidity 100%) for the first 48 h. After 7 days, typical leaf blight symptoms started to develop on the leaves of inoculated plants. S. allii was reisolated from the lesions of inoculated plants, confirming Koch's postulates. No symptoms were observed on control plants. The host-parasite association of A. tuberosum and S. allii has been known only from China (1). S. alliacea has been recorded on several species of Allium, e.g. A. cepa, A. chinense, A. fistulosum, and A. tuberosum from Japan (4) and A. cepa from Korea (3). To the best of our knowledge, this is the first report of S. allii on garlic chives. No diseased plants were observed in commercial fields of garlic chives which involved regular application of fungicides. The disease therefore seems to be limited to organic garlic chive production. References: (1) P. K. Chi et al. Fungous Diseases on Cultivated Plants of Jilin Province, Science Press, Beijing, China, 1966. (2) P. A. Saccardo. Sylloge Fungorum Omnium Hucusque Congnitorum. XXV. Berlin, 1931. (3) The Korean Society of Plant Pathology. List of Plant Diseases in Korea, Suwon, Korea, 2009. (4) The Phytopathological Society of Japan. Common Names of Plant Diseases in Japan, Tokyo, Japan, 2000.

TREK-1 and Best1 channels mediate fast and slow glutamate release in astrocytes upon GPCR activation

Astrocytes release glutamate upon activation of various GPCRs to exert important roles in synaptic functions. However, the molecular mechanism of release has been controversial. Here, we report two kinetically distinct modes of nonvesicular, channel-mediated glutamate release. The fast mode requires activation of G(αi), dissociation of G(βγ), and subsequent opening of glutamate-permeable, two-pore domain potassium channel TREK-1 through direct interaction between G(βγ) and N terminus of TREK-1. The slow mode is Ca(2+) dependent and requires G(αq) activation and opening of glutamate-permeable, Ca(2+)-activated anion channel Best1. Ultrastructural analyses demonstrate that TREK-1 is preferentially localized at cell body and processes, whereas Best1 is mostly found in microdomains of astrocytes near synapses. Diffusion modeling predicts that the fast mode can target neuronal mGluR with peak glutamate concentration of 100 μM, whereas slow mode targets neuronal NMDA receptors at around 1 μM. Our results reveal two distinct sources of astrocytic glutamate that can differentially influence neighboring neurons.

First Report of Leaf Spot Caused by Septoria erigerontis on Erigeron strigosus in Korea

Erigeron strigosus Muhl. ex Willd., known as daisy fleabane, is native to North America and was accidently introduced to Korea in the 1990s (2). It is increasingly invasive in natural and managed ecosystems throughout Korea. In June 2011, a leaf spot was first observed on daisy fleabanes growing wild in Hongcheon County of Korea. A voucher specimen was deposited in the Korea University Herbarium (KUS-F25759). Symptoms developed on lower leaves as small, distinct, reddish brown lesions, which enlarged progressively and turned into pale, dull brown spots surrounded by dark purplish-brown margins. Black pycnidia became visible in the lesions. Pycnidia were epigenous, occasionally hypogenous, scattered, dark brown to rusty brown, globose, embedded in host tissue or partly erumpent, 60 to 160 μm in diameter, with ostioles measuring 10 to 30 μm in diameter. Conidia were straight to mildly curved or even flexuous, guttulate, hyaline, 30 to 75 × 1.5 to 2 μm, and one- to seven-septate. Based on the morphological characteristics, the fungus was consistent with Septoria erigerontis Peck (3,4). Conidia were harvested from cirrhi of pycnidia on leaf lesions with a drop of sterile water and then directly streaked onto water agar media using a bacterial loop. Isolates were incubated at 24°C for 48 h. Germinating conidia were individually transferred to potato dextrose agar (PDA) plates. An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46120). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 505 bp was deposited in GenBank (Accession No. JX480493). A GenBank BLAST search was conducted with the 505-bp sequence showing 100% identity with the sequences of S. erigerontis ex Erigeron annuus (EF535638, GU269862). Pathogenicity was tested by spraying leaves of three potted plants with a conidial suspension (2 × 10⁵ conidia/ml) harvested from a 4-week-old PDA culture. Control leaves were sprayed with sterile distilled water. The plants were placed in a dew chamber at 26°C in darkness and continuous dew for the first 24 h and then moved to a greenhouse bench. After 7 days, leaf spot symptoms identical to those observed in the field developed on the leaves inoculated with the fungus. No symptoms were observed on control plants. S. erigerontis was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. A leaf spot disease of E. strigosus associated with S. erigerontis has been reported in the United States and Canada (1). To our knowledge, this is the first report of leaf spot on E. strigosus caused by S. erigerontis outside of North America as well as in Korea. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA, Retrieved June 2, 2012. (2) S. H. Park. Colored Illustrations of Naturalized Plants of Korea. Ilchokak Publishers, Seoul, Korea, 1995. (3) M. J. Priest. Fungi of Australia: Septoria. ABRS/CSIRO Publishing, Melbourne, Australia, 1997. (4) E. Radulescu et al. Septoriozele din Romania. Ed. Acad. Rep. Soc. Romania, Bucuresti, Romania, 1973.

First Report of Leaf Blight Caused by Phomopsis ipomoeae-batatas on Sweet Potato in Korea

Ipomoea batatas (L.) Lam., belonging to the Convolvulaceae, is widely cultivated and used as an industrial resource as well as for food and feed worldwide (2). In September 2010, an unknown leaf blight was observed on leaves in Hoengseong County and Jecheon City in Korea. Symptoms were mostly observed in older leaves as cream to tan-brown lesions surrounded by purplish brown-to-dark brown margin. Each lesion was circular to irregular, not exceeding 10 mm, but coalesced to form larger lesions. Necrotic tissue fell out giving rise to shot-holes. A number of black pycnidia were present in the lesions of diseased leaves. The same symptoms were observed at several localities in Korea during 2010 and 2011 seasons. The voucher specimens (n = 5) were preserved in the Korea University Herbarium (KUS). Two isolates were obtained from the two samples (KUS-F25274 and KUS-F25361) and deposited in the Korean Agricultural Culture Collection (Accession Nos. KACC45680 and KACC45702). Pycnidia were amphigenous, but mostly epigenous, scattered, dark brown-to-rusty brown, globose, embedded in host tissue or partly erumpent, 110 to 170 μm in diameter, and with an ostiole of 25 to 40 μm in diameter. Alpha conidia were aseptate, lageniform, biguttulate, hyaline, and 5.5 to 8.0 × 3.5 to 4.5 μm. Beta conidia were absent. Based on the morphological characteristics, the fungus was consistent with Phomopsis ipomoeae-batatas Punith. (1,3). Preliminary identification of the fungal isolate was confirmed by molecular data. Genomic DNA was extracted from the two isolates. The D1/D2 region of 28S rDNA was amplified using the primers LROR and LR7, and sequenced. The resulting sequences of the two isolates were identical to each other, and were deposited in GenBank (Accession Nos. JX157848 and JX157849). A BLAST search showed that there was no matching sequence of P. ipomoeae-batatas. Therefore, these were the first 28S sequences for the species submitted to GenBank. The present sequences showed >98% similarity with 24 entries of Phomopsis spp. and Diaporthe spp. (teleomorph of Phomopsis spp.), indicating their close phylogenetic relationship. Pathogenicity was tested by spraying leaves of three potted plants with a conidial suspension (2 × 10⁶ conidia/ml), which was harvested from a 3-week-old culture on potato dextrose agar. Control leaves were sprayed with sterile water. The plants were placed in a dew chamber at 24°C in darkness and continuous dew for the first 24 h and then moved to a greenhouse bench. After 10 days, leaf blight symptoms that were identical to those observed in the field started to develop on the leaves inoculated with the fungus. No symptoms were observed on control plants. P. ipomoeae-batatas was reisolated from the lesions of inoculated plants, confirming Koch's postulates. Occurrence of leaf blight caused by P. ipomoeae-batatas on sweet potato has been reported in many countries (1,3). To our knowledge, this is the first report of the disease in Korea. The economic losses are of minor importance, because the disease is mostly present toward the end of growing season; however, attention must be paid considering that the pathogen may reduce the quality of vines used as fodder. References: (1) C. A. Clark and J. W. Moyer. Compendium of Sweet Potato Diseases. The American Phytopathological Society. St. Paul, MN, 1988. (2) I. G. Mok et al. J. Plant Biotechnol. 36:202, 2009. (3) E. Punithalingam. Phomopsis ipomoeae-batatas. IMI Descriptions of Fungi and Bacteria. Sheet 739, 1982.

Protease activated receptor 1-induced glutamate release in cultured astrocytes is mediated by Bestrophin-1 channel but not by vesicular exocytosis

Background

Glutamate is the major transmitter that mediates the principal form of excitatory synaptic transmission in the brain. It has been well established that glutamate is released via Ca²⁺-dependent exocytosis of glutamate-containing vesicles in neurons. However, whether astrocytes exocytose to release glutamate under physiological condition is still unclear.

Findings

We report a novel form of glutamate release in astrocytes via the recently characterized Ca²⁺-activated anion channel, Bestrophin-1 (Best1) by Ca²⁺ dependent mechanism through the channel pore. We demonstrate that upon activation of protease activated receptor 1 (PAR1), an increase in intracellular Ca²⁺ concentration leads to an opening of Best1 channels and subsequent release of glutamate in cultured astrocytes.

Conclusions

These results provide strong molecular evidence for potential astrocyte-neuron interaction via Best1-mediated glutamate release.

First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

First Report of Anthracnose of Tricyrtis macropoda Caused by Colletotrichum gloeosporioides in Korea

Tricyrtis macropoda Miq. (syn. T. dilatata Nakai), known as speckled toadlily, is a perennial herb native to China, Japan, and Korea. The plant has been highly praised for its beautiful flowers and rare populations in natural habitats. In September 2006, several dozen plants were heavily damaged by leaf spots and blight in cultivated plantings in the city of Pocheon, Korea. The infections with the same symptoms were repeated every year. In July 2011, the same symptoms were found on T. macropoda in the cities of Gapyeong and Osan, Korea. The leaf lesions began as small, water-soaked, pale greenish to grayish spots, which enlarged to form concentric rings and ultimately coalesced. A number of blackish acervuli were formed in the lesions. Acervuli were mostly epiphyllous, circular to ellipsoid, and 40 to 200 μm in diameter. Setae were two- to three-septate, dark brown at the base, paler upwards, acicular, and up to 100 μm long. Conidia (n = 30) were long obclavate to oblong-elliptical, sometimes fusiform-elliptical, guttulate, hyaline, and 12 to 20 × 4 to 6.5 μm (mean 15.4 × 5.2 μm). These morphological characteristics of the fungus were consistent with the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (2). Voucher specimens (n = 7) were deposited in the Korea University herbarium (KUS). Two isolates, KACC46374 (ex KUS-F25916) and KACC46405 (ex KUS-F26063), were deposited in the Korean Agricultural Culture Collection. Fungal DNA was extracted and the complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequences of 549 bp were deposited in Genbank (Accession Nos. JQ619480 and JQ619481). They showed 100% similarity with a sequence of C. gloeosporioides (EU32619). Isolate KACC46374 was used in a pathogenicity test. Inoculum was prepared by harvesting conidia from 3-week-old cultures on potato dextrose agar. A conidial suspension (2 × 10⁶ conidia/ml) was sprayed onto 15 leaves of three plants. Three noninoculated plants served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 24 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). After 5 days, typical leaf spot symptoms, identical to the ones observed in the field, started to develop on the leaves of inoculated plants. No symptoms were observed on control plants. C. gloeosporioides was reisolated from the lesions of inoculated plants, thus fulfilling Koch's postulates. An anthracnose associated with C. tricyrtii (Teng) Teng was recorded on T. formosana and T. latifolia in China (3) and on T. formosana in Taiwan (1), respectively, without etiological studies. The morphological features of C. tricyrtii are within the variation of C. gloeosporioides (2). To our knowledge, this is the first report of anthracnose of T. macropoda. This report has significance to indigenous plant resource conservation managers and scientists because T. macropoda has been listed as one of the 126 "Rare and Endangered Plants" by the Korea Forest Service since 1991. References: (1) K. Sawada. Rep. Dept. Agric. Gov. Res. Inst. Formosa 87: 1, 1944. (2) B. C. Sutton. Pages 1-27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, U.K. 1992. (3) S. C. Teng. Contrib. Biol. Lab. Sci. Soc. China 8:36, 1932.

First Report of Leaf Spot of Rudbeckia hirta var. pulcherrima Caused by Septoria rudbeckiae in Korea

Rudbeckia hirta L. var. pulcherrima Farw. (synonym R. bicolor Nutt.), known as the black-eyed Susan, is a flowering plant belonging to the family Asteraceae. The plant is native to North America and was introduced to Korea for ornamental purposes in the 1950s. In July 2011, a previously unknown leaf spot was first observed on the plants in a public garden in Namyangju, Korea. Leaf spot symptoms developed from lower leaves as small, blackish brown lesions, which enlarged to 6 mm in diameter. In the later stages of disease development, each lesion was usually surrounded with a yellow halo, detracting from the beauty of the green leaves of the plant. A number of black pycnidia were present in diseased leaf tissue. Later, the disease was observed in several locations in Korea, including Pyeongchang, Hoengseong, and Yangpyeong. Voucher specimens were deposited at the Korea University Herbarium (KUS-F25894 and KUS-F26180). An isolate was obtained from KUS-F26180 and deposited at the Korean Agricultural Culture Collection (Accession No. KACC46694). Pycnidia were amphigenous, but mostly hypogenous, scattered, dark brown-to-rusty brown, globose, embedded in host tissue or partly erumpent, 50 to 80 μm in diameter, with ostioles 15 to 25 μm in diameter. Conidia were substraight to mildly curved, guttulate, hyaline, 25 to 50 × 1.5 to 2.5 μm, and one- to three-septate. Based on the morphological characteristics, the fungus was consistent with Septoria rudbeckiae Ellis & Halst. (1,3,4). Morphological identification of the fungus was confirmed by molecular data. Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA.). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 528 bp was deposited in GenBank (Accession No. JQ677043). A BLAST search showed that there was no matching sequence of S. rudbeckiae; therefore, this is the first ITS sequence of the species submitted to GenBank. The ITS sequence showed >99% similarity with those of many Septoria species, indicating their close phylogenetic relationship. Pathogenicity was tested by spraying leaves of three potted young plants with a conidial suspension (2 × 10⁵ conidia/ml), which was harvested from a 4-week-old culture on potato dextrose agar. Control leaves were sprayed with sterile water. The plants were covered with plastic bags to maintain 100% relative humidity (RH) for the first 24 h. Plants were then maintained in a greenhouse (22 to 28°C and 70 to 80% RH). After 5 days, leaf spot symptoms identical to those observed in the field started to develop on the leaves inoculated with the fungus. No symptoms were observed on control plants. S. rudbeckiae was reisolated from the lesions of inoculated plants, confirming Koch's postulates. A leaf spot disease associated with S. rudbeckiae has been reported on several species of Rudbeckia in the United States, Romania, and Bulgaria (1-4). To our knowledge, this is the first report of leaf spot on R. hirta var. pulcherrima caused by S. rudbeckiae in Korea. References: (1) J. B. Ellis and B. D. Halsted. J. Mycol. 6:33, 1890. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ February 2, 2012. (3) E. Radulescu et al. Septoriozele din Romania. Ed. Acad. Rep. Soc. Romania, Bucuresti, Romania, 1973. (4) S. G. Vanev et al. Fungi Bulgaricae 3:1, 1997.

Predictors for lymph node metastasis in T1 colorectal cancer

BACKGROUND AND STUDY AIMS

It is critical that the risk of lymph node metastasis (LNM) is evaluated for determining the suitability of endoscopic resection for T1 colorectal cancer (CRC). Reported risk factors for LNM in completely resected T1 CRC are deep submucosal invasion, grade 3, angiolymphatic invasion, and budding. The aim of the present study was to identify the histopathologic factors associated with LNM in T1 CRC.

PATIENTS AND METHODS

The study involved 435 patients with T1 CRC treated by endoscopic or surgical resection between January 2001 and April 2010 at the National Cancer Center, Korea. The 435 patients were classified into two groups - those undergoing surgical resection (n = 324) and those undergoing endoscopic resection (n = 111). In the surgically resected group, details regarding depth of submucosal invasion, angiolymphatic invasion, tumor grade, budding, and background adenoma (BGA) were evaluated with respect to presence or absence of LNM. In the endoscopically resected group, the results of follow-ups and additional salvage surgeries were studied.

RESULTS

In the surgically resected group, LNM was detected in 42 patients (13.0 %). Grade 3, angiolymphatic invasion, budding, and the absence of BGA were identified as factors associated with LNM in univariate and multivariate analyses (P < 0.05). Among the 50 patients in the endoscopically resected group with high risk, three were diagnosed as being LNM-positive during the follow-up period. There was no LNM in the endoscopically resected group with low risk.

CONCLUSIONS

Grade 3, angiolymphatic invasion, budding, and the absence of BGA are the risk factors that predict LNM in patients with T1 CRC. In cases where endoscopically resected T1 CRC has no risk factor, cautious follow-up could be recommended. However, if the tumor has any risk factor, additional surgical resection should be considered.

First Report of Leaf Blight and Stem Canker of Pachysandra terminalis Caused by Pseudonectria pachysandricola in Korea

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 10⁶ conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

First Report of Powdery Mildew Caused by Golovinomyces biocellatus on Monarda didyma in Korea

Bergamot (Monarda didyma L.), which is native to eastern North America, is an aromatic herb in the family Lamiaceae. It is widely planted in gardens and parks for ornamental purposes and also grown indoors as a fragrant houseplant in Korea. In October 2007, several dozen bergamots planted outdoors in Bonghwa, Korea were found to be heavily infected with a powdery mildew. Symptoms first appeared as thin, white colonies, which subsequently developed into abundant growth on both sides of the leaves. Severe infections often caused leaf distortions and premature senescence. The same symptoms have also been found in bergamot plots in Osan, Suwon, Incheon, and Seoul from 2007 to 2011. Voucher specimens were deposited at Korea University, Seoul, Korea. Hyphae were septate, branched, and 4 to 8 μm wide. Appressoria on the mycelium were nipple shaped. Conidiophores arose from the lateral part of the hyphae, measured 100 to 180 × 10 to 12 μm, were simple, and produced two to four immature conidia in chains, followed by two to three cells. Conidia were hyaline, ellipsoid to barrel shaped, measured 28 to 40 × 16 to 20 μm (length/width ratio = 1.4 to 2.2), lacked distinct fibrosin bodies, and produced germ tubes on the subterminal position, with reticulate wrinkling of the outer walls. No chasmothecia were observed. The structures described above were typical of the Oidium subgenus Reticuloidium anamorph of the genus Golovinomyces, and the fungus measurements were compatible with those of Golovinomyces biocellatus (Ehrenb.) V.P. Heluta as described previously (1,4). The only other powdery mildew known on Monarda spp. is Neoerysiphe galeopsidis (1), which is clearly distinguished by its lobed hyphal appressoria and fine striations on conidial surfaces. To confirm the tentative identification based on morphological characteristics, internal transcribed spacer (ITS) rDNA sequences from two representative isolates (KUS-F23070 and F23117) were obtained using primers ITS5 and P3 as described by Takamatsu et al. (3). The resulting sequences of 523 bp were deposited in GenBank (Accession Nos. JN228358 and JN228359). A GenBank BLAST search produced an exact match for the sequences of G. biocellatus on several plants belonging to the Lamiaceae, with a 100% sequence similarity. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of five healthy potted bergamot plants. Five noninoculated plants served as controls. Plants were maintained in a greenhouse at 25 ± 2°C. Inoculated plants developed signs and symptoms after 6 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants. The powdery mildew infections of bergamot plants associated with G. biocellatus have been known in Europe (2) and Japan (4). The current work confirmed the occurrence of G. biocellatus infecting M. didyma in Korea. References: (1) U. Braun. Beih. Nova Hedw. 89:1, 1987. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory. ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , July 12, 2011, (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) S. Tanda. J. Agric. Sci. Tokyo Agric. Univ. 47:274, 1997.

Activation of protease activated receptor 1 increases the excitability of the dentate granule neurons of hippocampus

Protease activated receptor-1 (PAR1) is expressed in multiple cell types in the CNS, with the most prominent expression in glial cells. PAR1 activation enhances excitatory synaptic transmission secondary to the release of glutamate from astrocytes following activation of astrocytically-expressed PAR1. In addition, PAR1 activation exacerbates neuronal damage in multiple in vivo models of brain injury in a manner that is dependent on NMDA receptors. In the hippocampal formation, PAR1 mRNA appears to be expressed by a subset of neurons, including granule cells in the dentate gyrus. In this study we investigate the role of PAR activation in controlling neuronal excitability of dentate granule cells. We confirm that PAR1 protein is expressed in neurons of the dentate cell body layer as well as in astrocytes throughout the dentate. Activation of PAR1 receptors by the selective peptide agonist TFLLR increased the intracellular Ca²⁺ concentration in a subset of acutely dissociated dentate neurons as well as non-neuronal cells. Bath application of TFLLR in acute hippocampal slices depolarized the dentate gyrus, including the hilar region in wild type but not in the PAR1-/- mice. PAR1 activation increased the frequency of action potential generation in a subset of dentate granule neurons; cells in which PAR1 activation triggered action potentials showed a significant depolarization. The activation of PAR1 by thrombin increased the amplitude of NMDA receptor-mediated component of EPSPs. These data suggest that activation of PAR1 during normal function or pathological conditions, such as during ischemia or hemorrhage, can increase the excitability of dentate granule cells.

Caffeine-mediated inhibition of calcium release channel inositol 1,4,5-trisphosphate receptor subtype 3 blocks glioblastoma invasion and extends survival

Calcium signaling is important in many signaling processes in cancer cell proliferation and motility including in deadly glioblastomas of the brain that aggressively invade neighboring tissue. We hypothesized that disturbing Ca(2+) signaling pathways might decrease the invasive behavior of giloblastoma, extending survival. Evaluating a panel of small-molecule modulators of Ca(2+) signaling, we identified caffeine as an inhibitor of glioblastoma cell motility. Caffeine, which is known to activate ryanodine receptors, paradoxically inhibits Ca(2+) increase by inositol 1,4,5-trisphospate receptor subtype 3 (IP(3)R3), the expression of which is increased in glioblastoma cells. Consequently, by inhibiting IP(3)R3-mediated Ca(2+) release, caffeine inhibited migration of glioblastoma cells in various in vitro assays. Consistent with these effects, caffeine greatly increased mean survival in a mouse xenograft model of glioblastoma. These findings suggest IP(3)R3 as a novel therapeutic target and identify caffeine as a possible adjunct therapy to slow invasive growth of glioblastoma.