Isolation,identification and characterization of Staphylococcus sp. from Indian ethnic fermented fish product

Staphylococci from Sheedal of Northeast India was isolated, identified and characterized. All the isolated staphylococci were found to be coagulase negative. Based on the rpoB gene sequences followed by analysis using NCBI-BLAST software, seven species of Staphylococcus namely, S. piscifermentans, S. condimenti, S. arlettae, S. sciuri, S. warneri, S. nepalensis and S. hominis were recognized. Phylogenetic analyses revealed three major cluster groups. All the seven Staphylococcus showed their NaCl tolerance from 2 to 8%. No species was able to grow at 55°C. Except S. arlettae and S. sciuri, all the isolated staphylococcal species exhibited growth at pH 4–8. No isolated species was able to ferment mannitol, sucrose and arabinose. All the species exhibited moderate to maximum proteolytic and lipolytic activities. All the seven species were found to be sensitive to the antibiotics, namely, erythromycin, norfloxacin, ampicillin, streptomycin and vancomycin, whereas all were resistant to co-trimoxazole. Only S. piscifermentans was found antagonist to Salmonella enterica, Escherichia coli and Bacillus subtilis, although the clear zone was minimal. All the staphylococcal species except S. arlettae and S. sciuri exhibited hydrophobicity ranging from 25 to 66%. The observed characteristics of isolated Staphylococci from Sheedal revealed their role in fish fermentation.     

Unidirectional potentiation of binding between two anti-FBP MAbs: Evaluation of involved mechanisms

The monoclonal antibody MOv19 directed to a folate binding protein shows temperature-dependent potentiation of binding of the noncompeting monoclonal antibody MOv18 to the relevant antigen, but the mechanism involved in this phinomenon had remained unclear. Use of chimeric versions of both monoclonal antibodies and the F(ab′)₂ and fan fragments of MOv19 revealed an increment in MOv18 binding in all combinations irrespective of the orgin of the Fc portin of the monoclonal antibody. The potentiating effect of bivalent MOv19 fragments on ¹²⁵l-MOv18 binding was similar to that of the entire monoclonal antibody and occurred at saturating concentrations of both reagents at which monovalent binding prevails. Similarly, the monovalent fragment also induced a significant increase in MOv18 bunding. Howener, the potentiation sccurred only at very high concentrations of antibody fragment. Homologous inhibition was drastically reduced using MOv19 Fab fragment, suggesting a low binding stability of the monovalent reagent. Immunoblotting analysis and binding in the presence of exogenous purified folate binding protein indicated a cross-linking between soluble and cell surface molecules mediated by the bivalent monoclonal antibodies. The extentof the increase in MOv18 binging at O°C with high amounts of exogenous folate binding protein was lower than that obtained at 37⁰C in the absence of added molecule. Release of ¹²⁵l-MOv18 from the cell surface was significantly higher in the absence of MOv19 than in its presence. Affinity constant values of ¹²⁵l-MOv18 binding evaluated in the presence of MOv19 or control monoclonal antibody MINT5 were comparable, whereas the number of binding sites per cell detected by ¹²⁵l-MOv18 was significantly higher in the presence of MOv19 than MINT5. Together, the data suggest that monoclonal antibody MOv19 induces a conformational change of the molecule it binds that increases the number of antigenic sites anvailable for MOv18 binding and, in turn, the binding stability of the latter, MOv19 bivalency also contributes to the MOv18 binding increment by cross-linking released and cell surface–anchored folate binding protein molecules. © Wiley-Liss, Inc.     

Coccidian Parasites of Intertidal Fishes from Wales: Systematics, Development, and Cytochemistry

SYNOPSIS. Examination of littoral fish Blennius pholis and Cottus bubalis caught at Aberystwyth and Porth Cwyfan, Wales. U.K., revealed 2 species of coccidia.
Eimeria dingleyi sp. n. Oocysts spherical (16.1–19.2) to subspherical (13.9–14.2 × 18.8–20.0) μm, with thin walls; sporulation outside the host to produce ellipsoid sporocysts; endogenous phases in epithelial cells throughout intestine; 26 of 58 B. pholis infected.
Eimeria variabilis (Thélohan) Reichenow. Oocysts spherical (11.9–14.6) to subspherical (9.2–10.9 × 13.9–14.3) μm; sporulation in lining of pyloric ceca and rectum; previously unrecorded schizonts and gametocytes present; 21 of 25 C. bubalis infected.
Electron microscopy revealed that the oocyst wall of E. variabilis consists of a thin membrane whereas the sporocyst wall is thick and 3-layered. Typical oocyst wall-forming bodies were absent from the macrogamete. Cytochemical tests on the endogenous stages of E. dingleyi and E. variabilis indicated that in general they resembled other coccidia in their chemical constitution.     

An intestinal cell-mediated chromosome aberration test for the detection of genotoxic agents

The use of rat-liver S9 in genotoxicity tests may not reflect true metabolism by whole cells, particularly cells of target organs. We have tested mucosal cells of the mouse small intestine for the capacity to mediate activation/inactivation of chemical carcinogens. Mucosal cells were isolated by pronase digestion. Three million cells were co-cultured with Chinese hamster ovary fibroblasts during a 3-h exposure to chemical clastogens. In the presence of the mucosal cells, aflatoxin B1 (100 microM) was activated to produce chromosome aberrations in 30% of Chinese hamster ovary cell metaphases. 4-Nitroquinoline 1-oxide was deactivated by intestinal cells, while benzo[a]pyrene and dimethylbenz[a]anthracene were not activated by the cells. The clastogenicity of the phenolic compounds caffeic acid (0.28 mg/ml) and clorogenic acid (0.25 mg/ml) was eliminated by the mouse intestinal preparation. The pyrrolizidine alkaloid monocrotaline was activated by intestinal cells. The results suggest the presence of specific activation and deactivation enzymes in the intestinal mucosa. The intestine cell-mediated chromosome aberration test could provide a means to measure tissue-specific activation and deactivation capabilities.     

The distribution and abundance of young fish in the Banc d'Arguin,Mauritania

The importance of the Banc d'Arguin (Mauritania) for juvenile fish has been investigated in September 1988. Fish have been sampled with a 2 m beam trawl at 50 locations in the coastal zone between Cap Sainte Anne and Cap Timiris. Water depth varied between 1 and 16 metres. Temperature and salinity at each station have been measured, as well as the weight of the catch and total length of the individual fish. The largest catches — in numbers as well as in weight — were obtained around the shallows of Tidra and Arel. This region has a large diversity in species, and contains large numbers of juvenile fish and cephalopods. The deeper areas seem to be much poorer in species, but average length and weight of the sampled fish are higher than around Tidra and Arel.     

Adaptations for matrotrophy in the female reproductive system in the pseudoscorpion Chelifer cancroides (Chelicerata: Pseudoscorpiones,Cheliferidae)

Pseudoscorpiones (pseudoscorpions, false scorpions) is an order of small terrestrial chelicerates. While most chelicerates are lecithotrophic, that is, embryos develop due to nutrients (mostly yolk) deposited in the oocyte cytoplasm, pseudoscorpions are matrotrophic, that is, embryos are nourished by the female. Pseudoscorpion oocytes contain only a small amount of yolk. The embryos develop within a brood sac carried on the abdominal site of the female and absorb nutrients by a pumping organ. It is believed that in pseudoscorpions nutrients for developing embryos are produced in the ovary during a postovulatory (secretory) phase of the ovarian cycle. The goal of our study was to analyze the structure of the female reproductive system during the secretory phase in the pseudoscorpion Chelifer cancroides, a representative of the family Cheliferidae, considered to be one of the most advanced pseudoscorpion taxa. We use diverse microscopic techniques to document that the nutritive fluid is produced not only in the ovaries but also by the epithelial cells in the oviducts. The secretory active epithelial cells are hypertrophic and polyploid and release their content by fragmentation of apical parts. Our observations also indicate that fertilization occurs in the oviducts. Moreover, in contrast to previous findings, we show that secretion of the nutritive material starts when the fertilized oocytes reach the brood sac and thus precedes formation of the pumping organ. Summing up, we show that C. cancroides exhibits traits of advanced adaptations for matrotrophy due to coordinated secretion of the nutritive fluid by the ovarian and oviductal epithelial cells, which substantially increases the efficiency of nutritive fluid formation. Since the secretion of nutrients starts before formation of the pumping organ, we suggest that the embryos are able to absorb the nutritive fluid also in the early embryonic stages.     

Response of instream animal communities to a short-term extreme event and to longer-term cumulative impacts in a strategic water resource area,South Africa

Disturbance plays an integral part in generating heterogeneity required for ecosystem persistence, but the increased amplitude and duration of disturbances linked to drivers of global change could result in ecosystem shifts or collapse. Biomonitoring over time provides insights into trajectories of ecosystem change. The responses of two instream animal taxa to two contrasting disturbance events, a major flood event and the long-term cumulative effects of land-use changes, were assessed in 1999–2012 by quantifying variation and change in abundance of functional groups based on flow rate sensitivity, water quality and metrics of ecological condition. All metrics recovered to pre-flood conditions within seven months after the flood event. Similarly, cumulative impacts of land use effected significant decreases in some but not all metrics. Indices that did not change, including SASS total score and ASPT, were the result of insufficient consideration of the decrease in the abundance of sensitive taxa specifically, and the abundance of all taxa in general. The decrease in abundance of sensitive taxa could signal imminent collapse in certain metrics. Evidence is also provided for a shift in the structure of fish assemblages linked to the decrease and loss of taxa sensitive to ecosystem degradation caused by the longer-term impacts of land-use change.