A photoluminescent layer for improving the performance of dye-sensitized solar cells

The η of a DSSC coated with a pyrene photoluminescent layer improves from 9.12 to 10.30%.

Characterization ofD-Aminoacylase fromAlcaligenes denitrificansDA181

The D-aminoacylase produced by Alcaligenes denitrificans DA181 was a new type of aminoacylase which had both high stereospecificity and specific activity. The molecular weight and isoelectric point of this enzyme were 58,000 and 4.4, respectively. The apparent Km and kcat values of this enzyme for N-acetyl-D-methionine were estimated to be 0.48 mM and 6.24 x 10(4) min-1, respectively. The optimum temperature was 45 degrees C. The enzyme was stable up to 55 degrees C for 1 hr in the presence of 0.2 mg/ml bovine serum albumin. The enzyme was stable in the pH range of 6.0 to 11.0 with an optimum pH of 7.5. This enzyme contained about 2.1 g atom of zinc per mole of enzyme. Enzyme activity was inhibited by incubation with EDTA. The inhibition by EDTA was fully reversed by Co2+ and partially by Zn2+.

Scanning electrochemical microscopy for study of aptamer-thrombin interfacial interactions on gold disk microelectrodes

A feasibility for the determination of thrombin on gold disk microelectrodes (GDMs) using scanning electrochemical microscopy (SECM) is reported. The assembly process step-by-step of thrombin aptasensor on GDMs is monitored by SECM. SECM analysis reveals the immobilization of thrombin aptamers on GDMs. The interaction between thrombin aptamers and thrombin on GDMs is imaged by SECM with feedback mode using ferrocenemethanol as an electrochemical mediator. The formation of thrombin/thrombin aptamer complex on GDMs results in a decrease in the tip peak current on spatial SECM images. This method is able to linearly and selectively detect thrombin over a linear range from 10(-12) to 10(-5)M with a detection limit of 6.07 fM.

The prognostic value of circumferential resection margin in esophageal squamous cell carcinoma after concurrent chemoradiation therapy and surgery

BACKGROUND

Despite the significant advances in surgical techniques and multimodality treatments for esophageal cancer, the overall survival remains unsatisfactory. During the past years, efforts were made to determine the prognostic factors that would help in identifying patients suitable for surgery or guiding adjuvant therapy. Positive circumferential resection margins (CRMs) in esophageal cancer have been previously linked with poor prognosis, but their impact on survival remains controversial in patients treated by a multimodality protocol. The aim of our study was to examine the significance of tumor involvement of CRM in patients with esophageal squamous cell carcinoma after concurrent chemoradiation therapy followed by esophagectomy.

METHODS

Between 2000 and 2010, 94 esophageal squamous cell carcinoma patients who received preoperative concurrent chemoradiation therapy followed by surgery were enrolled in our study. We focused on the CRM, which was defined microscopically as clear (negative) or involved (positive). Univariate and multivariate survival analyses were performed with overall survival as the endpoint.

RESULTS

Our cohort was predominantly male (94.7%) with a median age of 57 years. All of them received concurrent chemoradiation therapy followed by esophagectomy. Overall, 17 patients (18.1%) had positive CRM. Kaplan-Meier survival analysis demonstrated that the 5-year overall survival of patients with clear and involved CRM is 60.1% and 11.8%, respectively (log rank p < 0.001). Multivariate analysis with the Cox proportional hazard model demonstrated that CRM involvement is a significant prognostic factor for overall survival (p < 0.001).

CONCLUSION

In patients with esophageal squamous cell carcinoma who underwent trimodality treatment, CRM involvement is a significant risk factor predicting survival. Additional effort is required to achieve a clear CRM in esophageal cancer treatment.

Abstract 1777: Genome-wide identification of replication-associated breakpoints

Previous studies have defined sequences that are difficult to replicate and, consequently, are more vulnerable to replication-associated breaks and recombination events. However, many of these sequences have been identified through indirect and biased approaches. To identify genomic sequences that contribute to replication-associated breakpoints, we have performed genome-wide screens to determine the location, sequence, and frequency of replication perturbations within the mammalian genome. To convert these transient pause sites in S phase into longer-lived intermediates, asynchronous ATR-inhibited cells were treated with a low dose of polymerase inhibitor (0.2 μM aphidicolin) to promote selective replication fork collapse at difficult-to-replicate sequences. Affected regions were then isolated by chromatin immunoprecipitation of RPA (RPA-ChIP) and by a recently developed novel DNA breakpoint isolation method. Following deep sequencing, these sites were mapped within 1-5 kb regions and sequences at the center of these peaks were binned to quantify the overall frequency of replication fork collapse at such sites. Surprisingly, sequences that have long been thought to be among the most difficult to replicate, such as CGG repeats, were overshadowed by distinct repetitive sequences that are relatively uncharacterized. These sites were greater than 50-fold enriched over background, and were more common as replication-troubled regions than other well characterized sequences (e.g. triplet repeats, fragile sites, etc). In total, over 100 independently confirmed sites were identified, with most sequences observed in multiple locations across the genome. Notably, common fragile sites, which have been speculated to harbor such replication slow zones, were not observed to be particularly enriched in RPA-ChIP samples, consistent with recent observations that these sites are fragile for reasons other than impeded DNA replication rates. These findings and others indicating a larger role of chromatin structure in common fragile site breakage will be discussed.

Citation Format: Yu-Chen Tsai, Nishita Shastri, Kevin D. Smith, Jonathan Schug, Rafael Casellas, Eric J. Brown. Genome-wide identification of replication-associated breakpoints. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1777. doi:10.1158/1538-7445.AM2013-1777

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Drosophila king tubby (ktub) mediates light-induced rhodopsin endocytosis and retinal degeneration

Background

The tubby (tub) and tubby-like protein (tulp) genes encode a small family of proteins found in many organisms. Previous studies have shown that TUB and TULP genes in mammalian involve in obesity, neural development, and retinal degeneration. The purpose of this study was to investigate the role of Drosophila king tubby (ktub) in rhodopsin 1 (Rh1) endocytosis and retinal degeneration upon light stimulation.

Results

Drosophila ktub mutants were generated using imprecise excision. Wild type and mutant flies were raised in dark or constant light conditions. After a period of light stimulation, retinas were dissected, fixed and stained with anti-Rh1 antibody to reveal Rh1 endocytosis. Confocal and transmission electron microscope were used to examine the retinal degeneration. Immunocytochemical analysis shows that Ktub is expressed in the rhabdomere domain under dark conditions. When flies receive light stimulation, the Ktub translocates from the rhabdomere to the cytoplasm and the nucleus of the photoreceptor cells. Wild type photoreceptors form Rh1-immunopositive large vesicles (RLVs) shortly after light stimulation. In light-induced ktub mutants, the majority of Rh1 remains at the rhabdomere, and only a few RLVs appear in the cytoplasm of photoreceptor cells. Mutation of norpA allele causes massive Rh1 endocytosis in light stimulation. In ktub and norpA double mutants, however, Rh1 endocytosis is blocked under light stimulation. This study also shows that ktub and norpA double mutants rescue the light-induced norpA retinal degeneration. Deletion constructs further demonstrate that the Tubby domain of the Ktub protein participates in an important role in Rh1 endocytosis.

Conclusions

The results in this study delimit the novel function of Ktub in Rh1 endocytosis and retinal degeneration.

Sensitive electrochemical thrombin aptasensor based on gold disk microelectrodearrays

The construction of a sensitive electrochemical aptamer sensor (aptasensor) for thrombin detection is described. Among the advantages of using microelectrode-based devices are the possibility to work with small sample volumes and enjoying faster mass transport rates and lower interfacial capacitance than at macroelectrodes. Therefore, gold disk microelectrode arrays are an attractive transducer option for aptasensors. The morphology of the gold disk microelectrode arrays was inspected by scanning electron microscope. The interaction between a thrombin aptamer and thrombin on gold disk microelectrode arrays was demonstrated by differential pulse voltammetry using methylene blue (MB) as an electrochemical indicator. MB adsorbed to aptamers via their guanine base. When thrombin was introduced, it displaced the MB adsorbed to the aptamers and bound to them. This resulted in a decrease of MB peak current which correlated to the concentration of thrombin over a dynamic range spanning from 10⁻⁵ to 10⁻¹² M. This method was able to linearly and selectively detect thrombin with a detection limit of 0.143 pM.

Autocrine and paracrine unpaired signaling regulate intestinal stem cell maintenance and division

The Janus kinase (JAK) signal transducer and activator of transcription (STAT) pathway is involved in the regulation of intestinal stem cell (ISC) activity to ensure a continuous renewal of the adult Drosophila midgut. Three ligands, Unpaired 1, Unpaired 2 and Unpaired 3 (Upd1, Upd2 and Upd3, respectively) are known to activate the JAK/STAT pathway in Drosophila. Using newly generated upd mutants and cell-specific RNAi, we showed that Upd1 is required throughout the fly life to maintain basal turnover of the midgut epithelium by controlling ISC maintenance in an autocrine manner. A role of Upd2 and Upd3 in basal conditions is discernible only in old gut, where they contribute to increased ISC abnormal division. Finally, upon an acute stress such as oral bacterial infection, we showed that Upd3 is released from enterocytes and has an additive effect with Upd2 to promote rapid epithelial regeneration. Taken together, our results show that Upd ligands are required to maintain the midgut homeostasis under both normal and pathological states.

First Report of Didymella bryoniae Causing Gummy Stem Blight of Chayote in Taiwan

Chayote (Sechium edule (Jacq.) Swartz, Cucurbitaceae), originally native to Mexico, is an important vegetable known as "dragon-whisker vegetable" and is cultivated for its shoots in Ji-an, Hualien County in eastern Taiwan. In June 2010, 70 to 80% of the chayote plants grown in Ji-an developed necrotic spots on stems, leaves, and fruits. The disease was severe during the warm and rainy season from June to August. The symptoms on stems, leaves, and fruits were water-soaked lesions that eventually dried up, cracked, and produced perithecia on necrotic tissues. A single ascospore was isolated from perithecia harvested from diseased stems and cultured on potato dextrose agar (PDA) at 25°C for 1 month. Colonies of three isolates (SE5, SE6, and SE7) were white to olivaceous green bearing unicellular conidia measuring 2 to 5 × 3 to 10 μm, which is consistent with the morphological characteristics of Didymella bryoniae (Auersw.) Rehm (anamorph Phoma cucurbitacearum (Fr.:Fr.) Sacc.) (1,2,3). DNA of SE5, SE6, and SE7 isolates were obtained using microwave-based method (4). The internal transcribed spacer (ITS) rDNA (GenBank accessions AB714984, AB714985, and AB714986), PCR-amplified using primers ITS1 and ITS4, had 98 to 99% nucleotide sequence identity with D. bryoniae (GenBank Accession Nos. GU045304 and GU592001). A pathogenicity test was conducted in a greenhouse with temperature ranging from 20 to 30°C. Three-day-old mycelial plugs (5 × 5 mm) of the three isolates were placed on the needle-pricked wounds of stems and leaves of 36 4-month-old potted chayote plants wrapped in plastic bags to maintain 100% relative humidity for 2 days. Six days after inoculation, water-soaked lesions formed on the stems and leaves. Controls inoculated with sterile water had no symptoms. The fungus reisolated from the lesions of diseased stems and leaves had morphological characteristics of D. bryoniae. Based on the results of morphology, molecular data, and pathogenicity tests, we reported for the first time to our knowledge that gummy stem blight of chayote is caused by D. bryoniae in Taiwan. References: (1) J. W. Huang and W. R. Hsieh. Plant Prot. Bull. 27:325, 1985. (2) A. P. Keinath et al. Phytopathology 85:364, 1995. (3) E. Punithalingam and P. Holliday. P. 332 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972. (4) S. R. Tendulkar et al. Biotechnol. Lett. 22:1941, 2003.

Detrimental effects of maternal lead exposure during pregnancy and lactation on molar development in the young rat

The purpose of this animal study was to investigate the influence of maternal lead exposure during pregnancy and lactation on molar development in the offspring. Scanning electron microscopy revealed no significant differences in the molar morphology among the groups. However, in all the experimental groups, deep, wide cracks were found in the occlusal enamel. Further, the experimental groups had smaller molar diameters than the control group, lead exposure during lactation had a greater influence on the molar size in the offspring, and the groups with the higher dose of lead exposure during pregnancy and lactation had significantly smaller molar sizes than the groups that received the lower dose. The mesiodistal and buccolingual diameters of molars were measured as 3.10 ± 0.07 and 1.95 ± 0.04 mm for control group, 2.97 ± 0.08 and 1.94 ± 0.01 mm for lactation group of low dose, 2.96 ± 0.05 and 1.84 ± 0.02 mm for lactation group of high dose, 3.09 ± 0.06 and 1.94 ± 0.04 mm for pregnancy group of low dose, and 3.02 ± 0.06 and 1.85 ± 0.06 mm for pregnancy group of high dose, respectively.

Parallel optical trap assisted nanopatterning on rough surfaces

There exist many optical lithography techniques for generating nanostructures on hard, flat surfaces over large areas. However, few techniques are able to create such patterns on soft materials or surfaces with pre-existing structure. To address this need, we demonstrate the use of parallel optical trap assisted nanopatterning (OTAN) to provide an efficient and robust direct-write method of producing nanoscale features without the need for focal plane adjustment. Parallel patterning on model surfaces of polyimide with vertical steps greater than 1.5 µm shows a feature size uncertainty better than 4% across the step and lateral positional accuracy of 25 nm. A Brownian motion model is used to describe the positional accuracy enabling one to predict how variation in system parameters will affect the nanopatterning results. These combined results suggest that OTAN is a viable technique for massively parallel direct-write nanolithography on non-traditional surfaces.

Polymerase chain reaction-restriction fragment length polymorphism analysis of the genes involved in the biosynthesis of the lipopolysaccharide of Pasteurella multocida

The lipopolysaccharide, also known as the somatic antigen or O-antigen, is an important virulence factor of Pasteurella multocida. In the current study, the genes involved in the biosynthesis of the outer core region of the lipopolysaccharide, which were obtained from somatic type reference strains and field strains of P. multocida, were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The PCR-RFLP analysis classified 11 out of the 16 serotypes into 5 PCR-RFLP types (I-V). Types I and V contain strains belong to serotypes 1 and 13, respectively. The rest of the PCR-RFLP types contain strains belong to certain groups of serotypes. Typing of 38 field strains from poultry using PCR-RFLP analysis and the gel diffusion precipitation test showed consistent results. These results indicate that the PCR-RFLP analysis can be a useful tool for rapid somatic typing of some strains of P. multocida.

Interferon-β signaling contributes to Ras transformation

Increasing evidence has pointed to activated type I interferon signaling in tumors. However, the molecular basis for such activation and its role in tumorigenesis remain unclear. In the current studies, we report that activation of type I interferon (IFN) signaling in tumor cells is primarily due to elevated secretion of the type I interferon, IFN-β. Studies in oncogene-transformed cells suggest that oncogenes such as Ras and Src can activate IFN-β signaling. Significantly, elevated IFN-β signaling in Ras-transformed mammary epithelial MCF-10A cells was shown to contribute to Ras transformation as evidenced by morphological changes, anchorage-independent growth, and migratory properties. Our results demonstrate for the first time that the type I IFN, IFN-β, contributes to Ras transformation and support the notion that oncogene-induced cytokines play important roles in oncogene transformation.

Abstract 3438: Oncogenes-induced interferon-beta: modulation of tranformation phenotypes through interferon-ISG15 autocrine signaling

ISG15 (interferon-stimulated gene 15), an ubiquitin-like protein (UBL), is a new tumor marker whose expression has been correlated with disease progression in bladder cancer and suggested to be prognostic for breast cancer. However, the molecular basis for, and the function of, ISG15 overexpression in tumors remain unclear. Here, we show that ISG15 overexpression in both breast cancer cells and oncogenic Ras-transformed mammary epithelial cells (MCF-10A) is due to elevated secretion of interferon-β. Moreover, interferon-β-ISG15 autocrine signaling in oncogenic Ras-transformed MCF-10A cells results in increased colony formation efficiency. Interestingly, gain of epithelial-mesenchymal transition (EMT) characteristics, including appearance of spindle-shaped cell morphology and EMT markers, as well as increased cell migration, in Ras-transformed MCF-10A cells is also dependent on interferon-β-ISG15 autocrine signaling. Our results demonstrate for the first time that tumor cell-secreted interferon-β may modulate tumor cell growth and migration through ISG15, suggesting potential cancer therapeutic approaches by antagonizing interferon autocrine signaling.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3438. doi:10.1158/1538-7445.AM2011-3438

Preparative chromatography of flavonoids and saponins in Gynostemma pentaphyllum and their antiproliferation effect on hepatoma cell

A preparative column chromatographic method was developed to isolate flavonoids and saponins from Gynostemma pentaphyllum, a Chinese Medicinal herb, and evaluate their antiproliferation effect on hepatoma cell Hep3B, with the standards rutin and ginsenoside Rb(3) being used for comparison. Initially the powdered G. pentaphyllum was extracted with ethanol, followed by eluting flavonoids and saponins with ethanol-water (30:70, v/v) and 100% ethanol, respectively, in an open-column containing 5 g of Cosmosil 75C(18)-OPN, and then subjected to HPLC-MS analysis. The flavonoid fraction was mainly composed of quercetin- and kaempferol-glycosides, while in saponin fraction, both ginsenoside Rb(3) and ginsenoside Rd dominated. Both fractions were more effective against Hep3B cells than the standards rutin and ginsenoside Rb(3), with the cell cycle being arrested at G0/G1 phase for all the treatments. Additionally, the inhibition effect followed a dose-dependent increase for all the sample treatments. The result of this study may be used as a basis for possible phytopreparations in the future with G. pentaphyllum as raw material.

The role of eyg Pax gene in the development of the head vertex in Drosophila

The Drosophila head vertex is composed of three ocelli, stereotypic bristle patterns and characteristic cuticles. It is derived from the fusion of two eye-antenna discs. The head vertex primordium is located at the anterior-dorsal region of the eye disc. The orthodenticle (otd) homeobox gene is expressed in the primordium and is functionally required for its development and patterning. Here we show that the Pax gene eye gone (eyg) is expressed adjacent to the otd expression domain in the eye disc. otd is required and sufficient to repress eyg transcription, thereby preventing eyg from expressing in the head vertex primordium. In otd mutant, eyg expression is derepressed in the head vertex primordium and is a major negative effector to block head vertex development. Therefore, otd not only needs to induce downstream effector genes to execute the development and patterning of the head vertex development, but also needs to actively repress the negative regulator eyg. In addition, eyg is required for the development of the lateral bristles in the head vertex. So eyg plays both positive and negative roles in head vertex development.

Lack of association of mannose-binding lectin gene polymorphisms with development and clinical manifestations of systemic lupus erythematosus in Chinese children

Mannose-binding lectin (MBL) gene polymorphisms may be associated with adult-onset systemic lupus erythematosus (SLE), but studies in children with SLE are rare. This study tested the genetic association between MBL polymorphisms and paediatric-onset SLE in a cohort of Chinese children in Taiwan. In all 150 children with SLE and 100 healthy controls of comparable age were genotyped for codon 52, 54 and 57 mutations of the MBL gene using a polymerase chain reaction–based assay. Clinical manifestations, organ involvement, disease activity, laboratory characteristics and outcome were recorded and compared between patients with different MBL genotypes. Codon 54 mutation was fairly common in both SLE patients and controls, whereas codon 52 and codon 57 mutations were not detected in our study subjects. No statistically significant differences were found in allele frequencies of the codon 54 mutation between SLE and control groups. Moreover, no association was found between this MBL polymorphism and clinical manifestations, organ involvement, disease activity, laboratory characteristics or outcome of SLE. These results suggest that MBL polymorphisms do not influence susceptibility to paediatric-onset SLE and do not influence clinical manifestations of SLE in Chinese children.