Overexpression of mltA in Edwardsiella tarda reduces resistance to antibiotics and enhances lethality in zebra fish

AIMS

The aim of this study was to investigate the role of membrane-bound lytic murein transglycosylase A (MltA) in a bacterial fish pathogen Edwardsiella tarda.

METHODS AND RESULTS

An mltA in-frame deletion mutant (ΔmltA) and an mltA overexpression strain (mltA(+)) of Edw. tarda were constructed through double-crossover allelic exchange and by transformation of a low-copy plasmid carrying the intact mltA into the ΔmltA mutant, respectively. Either inactivation or overexpression of MltA in Edw. tarda resulted in elevated sensitivity to β-lactam antibiotics and lower viability in oligotrophic or high osmotic environment than wild-type strain. Autolysis induced by EDTA was reduced in ΔmltA strain, while mltA(+) strain was virtually flimsy, indicating that MltA is responsible for the lysis effect. Moreover, mltA(+) strain exhibited significant increases in lipopolysaccharide (LPS) biosynthesis and virulence to zebra fish compared with wild-type strain.

CONCLUSIONS

The results indicated that MltA plays essential roles in β-lactam antibiotics and environmental stresses resistance, autolysis, LPS biosynthesis and pathogenicity of Edw. tarda. This is the first report that MltA has a virulence-related function in Edw. tarda.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided useful information for further studies on pathogenesis of Edw. tarda.

L-cysteine attenuates peroxynitrite-elicited cytotoxicity to spiral ganglion neurons: possible relation to hearing loss

OBJECTIVES

The purpose of this work was to investigate whether L-cysteine was able to protect spiral ganglion neurons (SGNs) against peroxynitrite (ONOO(-))-elicited toxicity.

METHODS

The rat SGNs were isolated and cultured in this work. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The morphological changes were examined under inverted phase contrast microscope. Cells underwent apoptosis were determined by TdT-mediated dUTP nick end labeling (TUNEL) assay. Intracellular glutathione (GSH) content, superoxide dismutase (SOD) activity and malonaldehyde (MDA) level were detected by biochemical methods. Laser scanning confocal microscope was employed to analyze cytosolic Ca(2+) concentration.

RESULTS

Results showed that ONOO(-) reduced the cell viability of SGNs in a time- and dose-dependent manner. ONOO(-)-triggered cell damage was further confirmed via apoptotic pathway rather than necrosis. Pretreatment with L-cysteine (5 mM) for 12 hours could almost completely rescue SGNs from ONOO(-)-induced damage. The decrease in intracellular GSH content and SOD activity, as well as the increase in MDA level induced by ONOO(-) were correspondingly antagonized by the administration of L-cysteine. Furthermore, L-cysteine can significantly inhibit elevation of Ca(2+) concentration induced by ONOO(-).

DISCUSSION

Our findings indicate that L-cysteine protects SGNs from ONOO(-)-induced damage via enhancing the antioxidative activity and, suppressing the lipid peroxidation as well as the release of cytosolic Ca(2+), thereby indicating that oxidation resistance was useful to prevent audiological diseases initiated by oxidative stress.

Overexpression of Interleukin-18 Induces Growth Inhibition, Apoptosis and Gene Expression Changes in a Human Tongue Squamous Cell Carcinoma Cell Line

OBJECTIVE: To investigate the role of interleukin-18 (IL-18) in regulating the growth of the human tongue squamous cell carcinoma cell line CRL-1623™. METHODS: The human IL18 gene was cloned and transfected into CRL-1623™ cells using the transfection vector pcDNA3.1(+). Investigations included analysis of cell viability, detection of apoptosis using annexin V—fluorescein isothiocyanate, assessment of caspase 3/7 activity and real-time reverse transcription—polymerase chain reaction to assess expression of the IL18, CCND1 (cyclin D1), CCNA1 (cyclin A1) and IFNG (interferon-γ) genes. RESULTS: Introduction of the IL18 gene inhibited cell proliferation at 24, 48 and 72 h after transfection compared with untransfected cells and cells transfected with blank pcDNA3.1(+) vector. Apoptotic cell numbers and caspase 3/7 activity were significantly enhanced by IL18 transfection. Levels of IL18 and IFNG mRNA were elevated and CCND1 mRNA was reduced after 48 h in IL18 transfected cells compared with wild-type cells. CONCLUSIONS: These findings suggest that IL-18 plays a role in the regulation of tongue squamous cell carcinoma and may represent a potential therapeutic target.

Stent-assisted coil embolization of complex wide-necked bifurcation cerebral aneurysms using the "waffle cone" technique. A review of ten consecutive cases

Endovascular treatment of complex, wide-necked bifurcation cerebral aneurysms is challenging.  Intra/extra-aneurysmal stent placement, the "waffle cone" technique, has the advantage of using a single stent to prevent coil herniation without the need to deliver the stent to the efferent vessel. The published data on the use of this technique is limited. We present our initial and follow-up experience with the waffle cone stent-assisted coiling (SAC) of aneurysms to evaluate the durability of the technique. We retrospectively identified ten consecutive patients who underwent SAC of an aneurysm using the waffle cone technique from July 2009 to March 2011. Clinical and angiographic outcomes after initial treatment and follow-up were evaluated. Raymond Class I or II occlusion of the aneurysm was achieved in all cases with the waffle cone technique. No intraoperative aneurysm rupture was noted. The parent arteries were patent at procedure completion. Clinical follow-up in nine patients (median 12.9 months) revealed no aneurysm rupture. Two patients had a transient embolic ischemic attack at 18 hours and three months after treatment, respectively. Catheter angiography or MRA at six-month follow-up demonstrated persistent occlusions of aneurysms in seven out of eight patients. Another patient had stable aneurysm occlusion at three-month follow-up study. Our experience in the small series suggests the waffle cone technique could be performed on complex, wide-necked aneurysms with relative safety, and it allowed satisfactory occlusions of the aneurysms at six months in most cases.

Single-nucleotide polymorphisms in the promoter of the growth hormone-releasing hormone receptor gene are associated with growth and reproduction traits in chickens

Growth hormone-releasing hormone receptor (GHRHR) plays a critical role in growth hormone (GH) synthesis, release and regulation in animals. The objective of this study was to investigate variations of the chicken GHRHR gene and their associations with growth and reproduction traits in 768 Beijing You chickens. Results revealed three single nucleotide polymorphisms (SNPs) in the promoter region of the gene (g.-1654A>G, g.-1411A>G and g.-142T>C). Association analysis revealed that the novel SNP g.-1654A>G had significant effects on chicken body weight at 7, 9, 11, 13, 17 weeks of age and the age of first egg as well as egg number at 32, 36 and 40 weeks. Significant association was also observed between g.-1411A>G and g.-142T>C with EN24. Moreover, the age of first egg was distinctly related with g.-142T>C (P < 0.05). Although significant statistical difference was not detected in GHRHR mRNA levels among genotypes of the SNPs (P > 0.05), strong expression variations of the gene were found between the ages 17 and 20 weeks in the population (P < 0.05). These results suggest that the three SNPs in the GHRHR promoter could be used as potential genetic markers to improve the growth and reproductive traits in chickens.

First Report of Nectria haematococca Causing Stem Rot of Soybean in China

In October 2010, soybean (Glycine max) plants growing in commercial soybean fields in Zengcheng City, Guangdong Province developed symptoms consisting of stem and root rot, yellowing, and defoliation of leaves. Reddish, spherical fruiting bodies appeared in lesions that developed on stems. Plants with symptoms were sampled from fields. Fruiting bodies were excised from diseased tissues. Microscopic examination revealed that they were perithecia, globose to pyriform, and measured 197 to 260 μm in diameter and 226 to 358 μm long. When squeezed gently, cylindrical to clavate asci, 7.2 to 9.6 μm in diameter and 75.4 to 92.0 μm long, containing eight ascospores were exuded from the perithecia. Ascospores were ellipsoid to obovate, two celled, slightly constricted at the septum, had longitudinal striations, and measured 4.9 to 6.0 μm in diameter and 10.6 to 15.0 μm long. The fungus was isolated from the basal stem tissues of diseased soybean plants and cultured on potato dextrose agar (PDA) medium amended with streptomycin sulfate. On PDA, the culture developed into blue-pigmented colonies with whitish mycelium that produced oval to cylindrical microconidia. Microconidia had 0 to 1 septum, ranged from 2.5 to 5.2 × 7.6 to 29.4 μm, and were produced on monophialides. Macroconidia were cylindrical to falcate, thick walled, 2 to 5 septa, and 3.5 to 6.0 × 25.4 to 66.8 μm. Chlamydospores were present and ranged from 6.8 to 13.6 × 5.5 to 9.5 μm. Orange-to-reddish perithecia were readily formed in old culture. These morphological characteristics were consistent with descriptions of Nectria haematococca (anamorph Fusarium solani) (1). The rDNA internal transcribed spacer (ITS) region and the fragment of translation elongation factor 1-alpha (EF1-α) genes of the fungus were amplified, respectively, with universal primers ITS1/ITS4 and ef1/ef2 primers and sequenced. BLAST searches showed that the ITS sequences of three isolates (GenBank Accession Nos. JN015069, JN190942, and JN190943) had 99% similarity with those of N. haematococca(GenBank Accession Nos. DQ535186, DQ535185, and DQ535183) and the EF1-α sequences of three isolates (GenBank Accession Nos. JN874641, JN874642, and JN874643) had 100% similarity with those of F. solani (GenBank Accession Nos. DQ247265 and DQ247327). Completion of Koch's postulates confirmed the pathogenicity of the isolates in a replicated experiment. Thirty-day-old soybean seedlings of cultivar Huaxia No. 3 were inoculated by soaking their root systems in a conidial suspension (10⁶ conidia per ml) for 30 min and then transplanted in plastic pots (20 cm in diameter) and incubated at 25 ± 2°C in a greenhouse. Control plants were treated with sterile water in the same way. There were four plants per pot and there were six replicates for each treatment. Within 3 weeks, more than 70% of the inoculated plants exhibited symptoms of leaf yellowing, stem rot, and root rots while control plants were symptomless. N. haematococca was reisolated from the diseased plants. To our knowledge, this is the first report of N. haematococca causing stem rot of soybean in China and the first description of sexual reproduction of F. solani causing soybean stem rot in nature. This pathogen may pose a serious threat to soybean production in China where soybean is a main crop. Reference: (1) C. Booth. The Genus Fusarium. CAB International, Wallingford, UK, 1971.

Long-term evaluation of gait initiation in six Parkinson's disease patients with bilateral subthalamic stimulation

Defined as the transient state between standing and walking, gait initiation is negatively affected in Parkinson's disease (PD), which often results in significant disability. Although deep brain stimulation (DBS) is the most common surgical procedure for PD, the long-term effects of DBS on gait initiation are not well studied. The present study evaluated the long-term effects of subthalamic nucleus (STN) DBS on the preparation phase of gait initiation using principal component (PC) analysis. Six patients with PD who had undergone STN DBS and 24 healthy control subjects were evaluated. PD subjects were assessed 11.3±10.3 (P1) and 78.9±10.6 (P2) months after surgery. PD subjects were tested with STN DBS in two conditions: without medication and with medication. PC analysis was applied separately for the vertical, anterior-posterior and medial-lateral components of ground reaction force (GRF) recorded during gait initiation. Three PC scores were chosen by the scree test for each GRF component and all these PC scores were used for calculating a standard distance between healthy controls and PD subjects. The Friedman test showed a significant difference in standard distance among conditions (P=0.004), with the post-hoc test recognizing differences among P1 conditions and P2 medication-on condition. The eigenvector loading factors pointed to major differences between PD conditions surrounding the maximum amplitude of vertical and anterior-posterior GRF. For the studied sample, all distances increased in the follow-up evaluation (P2) with and without medications, indicating a worsening in gait initiation after seven years.

Terahertz response and colossal Kerr rotation from the surface states of the topological insulator Bi2Se3

We report the THz response of thin films of the topological insulator Bi2Se3. At low frequencies, transport is essentially thickness independent showing the dominant contribution of the surface electrons. Despite their extended exposure to ambient conditions, these surfaces exhibit robust properties including narrow, almost thickness-independent Drude peaks, and an unprecedentedly large polarization rotation of linearly polarized light reflected in an applied magnetic field. This Kerr rotation can be as large as 65° and can be explained by a cyclotron resonance effect of the surface states.

Development and application of EST-based markers specific for chromosome arms of rye (Secale cereale L.)

To develop a set of molecular markers specific for the chromosome arms of rye, a total of 1,098 and 93 primer pairs derived from the expressed sequence tag (EST) sequences distributed on all 21 wheat chromosomes and 7 rye chromosomes, respectively, were initially screened on common wheat 'Chinese Spring' and rye cultivar 'Imperial'. Four hundred and fourteen EST-based markers were specific for the rye genome. Seven disomic chromosome addition lines, 10 telosomic addition lines and 1 translocation line of 'Chinese Spring-Imperial' were confirmed by genomic in situ hybridization and fluorescencein situ hybridization, and used to screen the rye-specific markers. Thirty-one of the 414 markers produced stable specific amplicons in 'Imperial', as well as individual addition lines and were assigned to 13 chromosome arms of rye except for 6RS. Six rye cultivars, wheat cultivar 'Xiaoyan 6' and accessions of 4 wheat relatives were then used to test the specificity of the 31 EST-based markers. To confirm the specificity, 4 wheat-rye derivatives of 'Xiaoyan 6 × German White', with chromosomes 1RS, 2R and 4R, were amplified by some of the EST-based markers. The results indicated that they can effectively be used to detect corresponding rye chromosomes or chromosome arms introgressed into a wheat background, and hence to accelerate the utilization of rye genes in wheat breeding.

A novel missense mutation of the ECM1 gene in a Chinese patient with lipoid proteinosis

Lipoid proteinosis (LP), is caused by loss-of-function mutations in the gene for extracellular matrix protein 1 (ECM1), and has been mapped to chromosome 1q21. We report the case of a 49-year-old Chinese woman with LP, who presented with a hoarse voice, easily damaged skin with poor wound healing, lesions and scarring on the skin, and bead-like papules around the eyelids. On physical examination, yellowish deposits were seen on the soft palate, with thickening of the vocal cords. The coding region of ECM1 was amplified and sequenced, and a novel homozygous single-nucleotide substitution, c.1429T>C, was found in exon 9, which converts cysteine to arginine, designated p.C477R. This mutation was not founded in 100 unrelated normal genomic DNA sequences. In conclusion, this is a novel mutation in the ECM1 gene, which is the underlying cause of LP in this patient.

Emergence of resistance to fluoroquinolones and third-generation cephalosporins in Shigella flexneri subserotype 1c isolates from China

We report here on the first identification of Shigella flexneri subserotype 1c in China. We also report the emergence of resistance to ciprofloxacin and third-generation cephalosporins in this subserotype 1c for the first time. Isolates of seven strains circulating in China yielded three new sequence types and seven pulsed-field gel electrophoresis patterns, thus demonstrating the existence of high genetic diversity within the isolates. Overall, the seven isolates showed reduced susceptibility to ciprofloxacin; one isolate was ciprofloxacin resistant, whilst another developed resistance to ciprofloxacin, norfloxacin, cefotaxime and ceftriaxone.

New serum biomarkers for detection of endometriosis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

This study used proteomic fingerprint technology, combining nano-sized magnetic beads with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), to screen for potential protein biomarkers for the diagnosis of endometriosis. Serum proteins from 126 patients with endometriosis and 120 healthy controls were profiled and compared. Biomarker pattern software identified 46 discriminating mass-to-charge m/z ratio peaks that were related to endometriosis. The model constructed by the software, based on three of these peaks (m/z 5988.7, 7185.3 and 8929.8), generated excellent separation between the endometriosis and control groups. The sensitivity was 91.4% and the specificity 95.0%. Blind testing on a second series of serum samples from patients with endometriosis and healthy controls indicated a sensitivity of 89.3% and a specificity of 90.0%. Biomarkers for endometriosis can be discovered in serum by MALDI-TOF-MS in combination with nano-sized magnetic beads. The pattern of combined markers provides a powerful and reliable diagnostic method for endometriosis, with high sensitivity and specificity.

Qiliqiangxin improves cardiac function in spontaneously hypertensive rats through the inhibition of cardiac chymase

BACKGROUND

This study was designed to investigate the effects and mechanism of action of the traditional Chinese drug formula, qiliqiangxin (QLQX), on cardiac function in spontaneously hypertensive rats (SHRs).

METHODS

We evaluated the effects of oral high-dose (4 g/kg/day, n = 7) and low-dose (1 g/kg/day, n = 7) QLQX on cardiac function in SHRs aged between 8 compared to control, the 8-week-old Wistar-Kyoto (WKY) rats. Echocardiography was performed to evaluate cardiac function and hemodynamic parameters. Hematoxylin and eosin (HE) and Masson's trichrome staining were performed, and the expression of myocardial angiotensin (Ang)-converting enzyme, chymase, transforming growth factor (TGF)-β, and collagen-type I and III were evaluated with real-time reverse transcription-PCR. Myocardial chymase, Ang-converting enzyme (ACE), and Ang II activities were measured with radioimmunoassay (RIA) techniques. Cardiac mast cells were detected with toluidine blue staining.

RESULTS

In SHRs, the number of chymase enzyme-positive mast cells increased in the left ventricle (LV) compared with WKY rats. QLQX significantly decreased mast cell density and cardiac chymase levels, and it improved ejection fraction values and cardiac systolic function compared with vehicle. Moreover, QLQX decreased left atrial diameters and improved the E/A ratio. QLQX suppressed collagen-type I and III and TGF-β mRNA levels, and Ang II activity, in a dose-dependent manner. Whereas no difference in ACE activity was found between SHRs, chymase expression and activity were significantly decreased with QLQX.

CONCLUSIONS

These data suggest that QLQX improves both systolic and diastolic cardiac function in SHRs through downregulating the cardiac chymase signaling pathway and chymase-mediated Ang II production.

Prevention and treatment of DNA vaccine encoding cockroach allergen Bla g 1 in a mouse model of allergic airway inflammation

BACKGROUND

One-fourth of the US population is sensitized to the German cockroach. Primary German cockroach allergen Bla g 1 is detected in 63% of homes and 52% of childcare facilities in the United States. No effective treatment or vaccination strategies are yet available.

OBJECTIVES

We evaluated the prophylactic and therapeutic efficacy of a plasmid DNA-mediated vaccination using the Bla g 1 gene in a mouse model of allergic inflammatory airway disease.

METHODS

A plasmid DNA vector coding for the Bla g 1 allergen controlled by cytomegalovirus promoter was constructed. To estimate the protective efficacy, BALB/c mice were given three injections of plasmid DNA-Bla g 1 prior to sensitization with two priming doses of recombinant Bla g 1 (rBla g 1) antigens, followed by nebulized rBla g 1 challenge. In the therapeutic approach, sensitization was followed by administering Bla g 1 DNA vaccine.

RESULTS

Bla g 1 vaccination significantly reduced allergen-induced airway inflammation, even after mice were presensitized and a Th2-dominant response was established. The Bla g 1 vaccination significantly reduced total inflammatory cell infiltrate, eosinophilia, secretion of Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, allergen-induced inflammatory infiltrates in the lungs, and Bla g 1-specific IgE in serum upon challenge with rBla g 1. Importantly, Bla g 1 DNA vaccination was able to induce IL-10-secreting regulatory T cells that could suppress the allergen-specific Th2 cells.

CONCLUSION

DNA vaccination showed protective and therapeutic efficacy against a clinically relevant allergen Bla g 1.

Efficacy and safety of embolization in iatrogenic traumatic uterine vascular malformations

AIM

To retrospectively evaluate the efficacy of embolotherapy in patients with iatrogenic traumatic uterine arteriovenous malformations (AVMs).

MATERIALS AND METHODS

A retrospective review of all patients who underwent uterine arterial embolization in Peking Union Medical College Hospital between January 2000 and December 2010 was performed. Forty-two patients were diagnosed with a uterine vascular malformation. All patients had obstetric manipulations before. Serial beta-human chorionic gonadotropin (β-HCG) levels were measured to exclude gestational trophoblastic neoplasia. All patients underwent transcatheter embolization of bilateral uterine arteries. The complications, control of haemorrhage, and outcome of subsequent pregnancies were assessed.

RESULTS

A total of 49 embolization procedures were performed in 42 patients. Seven patients required repeated embolizations for recurrence of bleeding. The technical success rate of embolization was 100%. Bleeding was controlled in 35 of 42 patients (83%) after the first embolization procedures, and bleeding was controlled in another two patients who underwent repeat embolization at a median follow-up of 29 months (range 3 months to 5 years). The overall clinical success rate was 88% (37/42). Thirteen patients subsequently became pregnant and eight of 13 patients had uneventful intrauterine pregnancies carried to term. Seven patients had post-embolization syndrome and no other complication occurred.

CONCLUSION

Percutaneous embolotherapy is a safe and effective treatment for traumatic AVMs. Future pregnancy is still possible after embolization.

Helicobacter pylori may cause otitis media with effusion: a pilot study

OBJECTIVES

To evaluate the presence of Helicobacter pylori (HP) in middle ear effusion from Chinese adult patients with otitis media with effusion (OME).

METHODOLOGY

A total of 60 aspiration samples collected from adult patients (ranging from 19 to 73 years old) were included in the study. The effusion samples aspirated from the patients' middle ears were analyzed with polymerase chain reaction (PCR) assay and cultured for 7 days under microaerobic conditions. Subsequently, Gram staining and urease testing were performed to identify HP.

RESULTS

Of the 60 middle ear effusion samples, 24 (40%) were shown to be HP-positive by PCR assay. Of these, seven specimens were confirmed HP-positive by both culture and urease test.

CONCLUSIONS

The present study clearly demonstrates the presence of HP in the middle ear effusion of some Chinese adult patients with OME. This finding suggests that HP may be involved in the etiology of OME. Additional studies are needed to investigate the exact role of HP in the pathogenesis of OME.