Genotoxic effects of estradiol-17beta on human lymphocyte chromosomes

The cytogenetic effect of a hormonal steroid, estradiol-17beta, was assessed in peripheral blood human lymphocyte culture. Sister chromatid exchanges (SCE) and chromosome aberrations (CA) were scored as genetic end points. Significant induction of CA was observed at 25 microg/ml and 50 microg/ml concentrations of estradiol-17beta in the absence of microsomal activation. The drug was effective in all treatments in the presence of rat liver S(9) microsomal fraction (S(9) mix) and exhibited increased frequency of chromosomal aberrations. The drug was effective in increasing the SCE frequency which was found to be maximum at the dose of 50 microg/ml concentration (i.e., 4.34+/-1.22) both with and without metabolic activation. It was found that estradiol-17beta itself and possibly its metabolites are potent mutagens beyond a particular dose in human lymphocytes.     

Gastric acid secretion in aquaporin-4 knockout mice

The aquaporin-4 (AQP4) water channel has been proposed to play a role in gastric acid secretion. Immunocytochemistry using anti-AQP4 antibodies showed strong AQP4 protein expression at the basolateral membrane of gastric parietal cells in wild-type (+/+) mice. AQP4 involvement in gastric acid secretion was studied using transgenic null (-/-) mice deficient in AQP4 protein. -/- Mice had grossly normal growth and appearance and showed no differences in gastric morphology by light microscopy. Gastric acid secretion was measured in anesthetized mice in which the stomach was luminally perfused (0. 3 ml/min) with 0.9% NaCl containing [(14)C]polyethylene glycol ([(14)C]PEG) as a volume marker. Collected effluent was assayed for titratable acid content and [(14)C]PEG radioactivity. After 45-min baseline perfusion, acid secretion was stimulated by pentagastrin (200 microg. kg(-1). h(-1) iv) for 1 h or histamine (0.23 mg/kg iv) + intraluminal carbachol (20 mg/l). Baseline gastric acid secretion (means +/- SE, n = 25) was 0.06 +/- 0.03 and 0.03 +/- 0.02 microeq/15 min in +/+ and -/- mice, respectively. Pentagastrin-stimulated acid secretion was 0.59 +/- 0.14 and 0.70 +/- 0.15 microeq/15 min in +/+ and -/- mice, respectively. Histamine plus carbachol-stimulated acid secretion was 7.0 +/- 1.9 and 8.0 +/- 1.8 microeq/15 min in +/+ and -/- mice, respectively. In addition, AQP4 deletion did not affect gastric fluid secretion, gastric pH, or fasting serum gastrin concentrations. These results provide direct evidence against a role of AQP4 in gastric acid secretion.     

Lithostratigraphy and sedimentology of the latest Cretaceous-early Burdigalian Tamezzakht succession (Northern Rif, Morocco): consequences for its sequence stratigraphic interpretation

The Tamezzakht succession (Maastrichtian–middle Burdigalian), situated at the fringe between the Internal and the External zones, displays contrasting lithologies with abrupt facies changes, discontinuities, and/or coarse-grained calciturbidite in between. These criteria allow the definition of seven main lithostratigraphic formations.Depositional environments (oxygenation levels, trophic conditions, omission histories, among others) and/or transgressive/regressive trends are inferred from integrated sedimentologic data including facies change, cyclicity pattern and the textural composition of the turbidite facies tracts. Special emphasis is given to the ichnological features.Taking into account the extended time-range, the position between the internal zones and the external ones, as well as the clear differentiation into several contrasting sedimentary formations, the Tamezzakht succession is expected to provide useful stratigraphic data for the regional correlations.     

Diversity and cold-active hydrolytic enzymes of culturable bacteria associated with Arctic sea ice,Spitzbergen

The diversity of culturable bacteria associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean, was investigated. A total of 116 psychrophilic and psychrotolerant strains were isolated under aerobic conditions at 4°C. The isolates were grouped using amplified rDNA restriction analysis fingerprinting and identified by partial sequencing of 16S rRNA gene. The bacterial isolates fell in five phylogenetic groups: subclasses and of Proteobacteria, the Bacillus–Clostridium group, the order Actinomycetales, and the Cytophaga–Flexibacter–Bacteroides (CFB) phylum. Over 70% of the isolates were affiliated with the Proteobacteria subclass. Based on phylogenetic analysis (<98% sequence similarity), over 40% of Arctic isolates represent potentially novel species or genera. Most of the isolates were psychrotolerant and grew optimally between 20 and 25°C. Only a few strains were psychrophilic, with an optimal growth at 10–15°C. The majority of the bacterial strains were able to secrete a broad range of cold-active hydrolytic enzymes into the medium at a cultivation temperature of 4°C. The isolates that are able to degrade proteins (skim milk, casein), lipids (olive oil), and polysaccharides (starch, pectin) account for, respectively, 56, 31, and 21% of sea-ice and seawater strains. The temperature dependences for enzyme production during growth and enzymatic activity were determined for two selected enzymes, -amylase and -galactosidase. Interestingly, high levels of enzyme productions were measured at growth temperatures between 4 and 10°C, and almost no production was detected at higher temperatures (20–30°C). Catalytic activity was detected even below the freezing point of water (at –5°C), demonstrating the unique properties of these enzymes.     

New species and new records of Ergasilus Nordmann (Copepoda: Ergasilidae) from the gills of grey mullet (Mugilidae)

Four new Ergasilus species are described from five host species of grey mullet, family Mugilidae, held in the fish collections of The Natural History Museum, London. Ergasilus extensus n. sp. was found on Myxus petardi (Castelnau) from Australia, E. sittangenesis n. sp. on Sicamugil hamiltoni (Day) from Burma, E. piriformis n. sp. on Sicamugil cascasia (Hamilton Buchanan) from India, and E. ecuadorensis n. sp. on Mugil curema Valenciennes and M. hospes Jordan & Culver from Ecuador. New records of E. cyanopictus Caravalho, E. magnicornis Yin, E. orientalis Yamaguti and E. rostralis Ho, Jayarajian & Radhakrishnan on grey mullet are also given.     

Improvement of β-glucosidase production by co-culture of Aspergillus niger and A. oryzae under solid state fermentation through feeding process

Eleven different Aspergillus strains were evaluated for their ability to produce β-glucosidase using sugar cane bagasse as a sole carbon source under solid state fermentation (SSF). The most potent strains, A. niger NRC 7 (674.6 U/g ds) and A. oryzae NRRL 447 (83 U/g ds), were used in a mixed culture to enhance β-glucosidase production by co-culturing under SSF. In mixed culture, β-glucosidase of the two strains (814 U/g ds) was nearly 1.2- and 9.8-fold than that of monocultures of A. niger NRC 7A and A. oryzae NRRL 447, respectively. Optimization of the culture parameters, initial pH value, moisture content, inoculum size and ratios of the two strains. and incubation time exhibited a significant increase in β-glucosidase production (1,893 U/g ds) than before optimization. Single feeding with citrate-phosphate buffer, succinate buffer, casein. and soybean flour individually after the third day of the fermentation time and controlling the moisture content at 90 % (w/w) induced β-glucosidase production. Maximum enzyme production increased up to 2.1-fold compared to 2,188 U/g ds during normal batch culture. Among nitrogen sources, soybean flour gave the highest β-glucosidase (4,578 U/g ds). while urea reduced β-glucosidase production (1,693 U/g ds). However, the combination of buffers with soybean flour through two fed cycles resulted in a decrease of the enzyme than single fed with buffers or soybean flour alone.     

Isolation of scFv antibody fragments against HER2 and CEA tumor antigens from combinatorial antibody libraries derived from cancer patients

Tumor cells expressing HER-2/neu and CEA antigens are potentially ideal targets for antibody-targeted therapy. In this study, two large human combinatorial libraries have been generated from the lymph nodes of breast cancer patients that express HER2 and CEA antigens in their tumors. These ‘immune’ libraries have been constructed in two different formats of scFv, differing in the length of the peptide linker connecting the two variable VH and VL domains. Libraries derived from these patients may contain a larger pool of anti-tumor antigen antibodies and are useful repertoire for isolating scFvs against any tumor markers. The results of this study showed that we were successful in obtaining human scFvs against HER-2/neu and CEA. For HER-2, cell-panning strategy was performed and resulted in two scFv binders that detected the complete HER-2 receptor on the cell membrane and internalized to the cells. Also, preliminary ELISA data showed that several anti-CEA scFv binders were isolated by panning.     

Influence of Small RNAs on Biofilm Formation Process in Bacteria

Small non-coding RNAs (sRNAs) play a significant role in regulation of bacterial physiological behaviors. After sensing any environmental cue such as fluctuation of nutrient concentration, temperature, pH, and osmolarity, these sRNAs interfere to transmit these signals to target regulators and genes. sRNAs have key role in biofilm formation process by base pairing with target mRNAs or interaction with modulating proteins to both positive and negative regulation mechanisms. There are various regulatory systems to characterize the initiation and formation of special bacterial biofilms that are mostly described as two component systems based on sRNAs functions. In this study, regulatory pathways that are important for biofilm formation and genetic responses to environmental stimuli in mature biofilms were evaluated. Some of the regulatory systems that produce common types of biofilms such as curli, PGA, cellulose and polysaccharides such as alginate, colonic acid, Psl and their involved sRNAs functions were also discussed.     

Castor bean organelle genome sequencing and worldwide genetic diversity analysis

Castor bean is an important oil-producing plant in the Euphorbiaceae family. Its high-quality oil contains up to 90% of the unusual fatty acid ricinoleate, which has many industrial and medical applications. Castor bean seeds also contain ricin, a highly toxic Type 2 ribosome-inactivating protein, which has gained relevance in recent years due to biosafety concerns. In order to gain knowledge on global genetic diversity in castor bean and to ultimately help the development of breeding and forensic tools, we carried out an extensive chloroplast sequence diversity analysis. Taking advantage of the recently published genome sequence of castor bean, we assembled the chloroplast and mitochondrion genomes extracting selected reads from the available whole genome shotgun reads. Using the chloroplast reference genome we used the methylation filtration technique to readily obtain draft genome sequences of 7 geographically and genetically diverse castor bean accessions. These sequence data were used to identify single nucleotide polymorphism markers and phylogenetic analysis resulted in the identification of two major clades that were not apparent in previous population genetic studies using genetic markers derived from nuclear DNA. Two distinct sub-clades could be defined within each major clade and large-scale genotyping of castor bean populations worldwide confirmed previously observed low levels of genetic diversity and showed a broad geographic distribution of each sub-clade.     

Polymorphisms in stromal genes and susceptibility to serous epithelial ovarian cancer: a report from the Ovarian Cancer Association Consortium

Alterations in stromal tissue components can inhibit or promote epithelial tumorigenesis. Decorin (DCN) and lumican (LUM) show reduced stromal expression in serous epithelial ovarian cancer (sEOC). We hypothesized that common variants in these genes associate with risk. Associations with sEOC among Caucasians were estimated with odds ratios (OR) among 397 cases and 920 controls in two U.S.-based studies (discovery set), 436 cases and 1,098 controls in Australia (replication set 1) and a consortium of 15 studies comprising 1,668 cases and 4,249 controls (replication set 2). The discovery set and replication set 1 (833 cases and 2,013 controls) showed statistically homogeneous (P_{heterogeneity}≥0.48) decreased risks of sEOC at four variants: DCN rs3138165, rs13312816 and rs516115, and LUM rs17018765 (OR = 0.6 to 0.9; P_trend = 0.001 to 0.03). Results from replication set 2 were statistically homogeneous (P_{heterogeneity}≥0.13) and associated with increased risks at DCN rs3138165 and rs13312816, and LUM rs17018765: all ORs = 1.2; P_trend≤0.02. The ORs at the four variants were statistically heterogeneous across all 18 studies (P_{heterogeneity}≤0.03), which precluded combining. In post-hoc analyses, interactions were observed between each variant and recruitment period (P_interaction≤0.003), age at diagnosis (P_interaction = 0.04), and year of diagnosis (P_interaction = 0.05) in the five studies with available information (1,044 cases, 2,469 controls). We conclude that variants in DCN and LUM are not directly associated with sEOC, and that confirmation of possible effect modification of the variants by non-genetic factors is required.