Trophic ecology and persistence of invasive silver carp Hypophthalmichthys molitrix in an oligotrophic South African impoundment

The alien invasive silver carp Hypophthalmichthys molitrix established a self-sustaining feral population in an oligotrophic impoundment, Flag Boshielo Dam, in South Africa. The ability of this population to persist in a dam with low algal biomass (median annual suspended chlorophyll a = 0.08 µg l^?1), and limited access to rivers considered large enough for successful spawning, has implications for their invasive potential in other systems. Stomach content and stable isotope analysis were used to assess the trophic ecology of H. molitrix, which was then compared with indigenous Mozambique tilapia Oreochromis mossambicus, on a seasonal basis during 2011. Hypophthalmichthys molitrix are generalist filter feeders, with a diet consisting primarily of sediment, vegetative detritus, dinoflagellates and diatoms. The dominance of sediments in their stomachs suggests occasional benthic scavenging. However, H. molitrix occupied a higher trophic level (TL = 2.8) than expected, suggesting that this population subsidised their diet with an unidentified dietary constituent, characterised by enriched nitrogen values. Although the stomach contents indicated dietary overlap between H. molitrix and O. mossambicus, stable isotopes revealed fine-scale resource partitioning, despite both species occupying the same trophic level. Nonetheless, the persistence of this feral H. molitrix population in an oligotrophic impoundment highlights their phenotypic plasticity.     

Extracting information from imaging cytometry: a review

The extraction of statistically meaningful quantitative information from microscopy images is increasingly important for modern biological research. Obtaining accurate, quantitative information from biological specimens, however, is a complex process that requires optimization of several parameters. One must consider the number of probes, fluorescent channels required, type of plate to be used, number of fields to be acquired and optimal resolution for image acquisition. The extraction of information from images is dependent on and can be aided greatly by careful consideration of the factors involved in the image acquisition process. I summarize here the general principles behind the imaging and software technology that is used to quantify images and highlight particular issues of concern for critically applying image quantitation techniques for research.     

A New Method for Extraction of Extravasated Dye in the Skin and the Influence of Fasting Stress on Passive Cutaneous Anaphylaxis in Guinea Pigs and Rats*

A method for quantitative extraction of extravasated dye from the skin was studied in guinea pigs and rats. A simple method with a low cost and good recovery was established as follows; A piece of the skin containing extravasated dye was soaked overnight in a stoppered glass tube containing 1 ml of 1 n KOH at 37 C. Then, 9 ml of a mixed solution of 0.6 n H₃PO₄ and acetone (5:13) was added to the tube. The tube was shaken vigorously for a few seconds and centrifuged at 3,000 rpm for 15 min. Absorbance of supernatant was measured at 620 nm. The recovery rate of the dye was about 95% both in guinea pigs and rats. Using this method we observed that fasting stress significantly reduced the intensity of skin reactions induced by chemical mediators, heterologous PCA and especially homologous PCA in guinea pigs.     

Glycosylation pattern of humanized IgG-like bispecific antibody produced by recombinant CHO cells

The glycosylation pattern of a humanized anti-EGFR×anti-CD3 bispecific single-chain diabody with an Fc portion (hEx3-scDb-Fc) produced by recombinant Chinese hamster ovary cells was evaluated and compared with those of a recombinant humanized anti-IL-8 antibody (IgG1) and human serum IgG. N-Linked oligosaccharide structures were estimated by two-dimensional high-performance liquid chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. No sialylation was observed with purified hEx3-scDb-Fc and the anti-IL-8 antibody. From the analysis of neutral oligosaccharides, approximately more than 90% of the N-linked oligosaccharides of hEx3-scDb-Fc and the anti-IL-8 antibody were alpha-1,6-fucosylated. The galactosylated biantennary oligosaccharides comprise over 40% of the total N-linked oligosaccharides in both hEx3-scDb-Fc and the anti-IL-8 antibody. The fully galactosylated biantennary oligosaccharides from hEx3-scDb-Fc and the anti-IL-8 antibody accounted for only 10% of the N-linked; however, more than 20% of the N-linked oligosaccharides were fully galactosylated biantennary oligosaccharides in human serum IgG. The glycosylation pattern of hEx3-scDb-Fc was quite similar to that of the anti-IL-8 antibody.     

Recognition of culture state using two-dimensional gel electrophoresis with an artificial neural network

Proteomic technologies were applied to the examination of nutrient components in culture broth. In bioprocesses, many types of media have been proposed and used on the commercial scale. Natural nutrients, the chemical components of which cannot be identified completely, are often used in fermentation processes such as in the production of baker's yeast, alcoholic beverages, amino acids, and pharmaceuticals. The catabolic activities of the microorganisms in these processes vary with the species used. We used an artificial neural network (ANN) to recognize the sufficiency of chemical elements based on the protein spots resolved in 2-DE, and we evaluated this technique using the leave-one-out method. We also attempted to reduce the number of input data for spot selection based on sensitivity analysis of the ANN, and the selected data were used to improve accuracy.     

Development of 3,4-dihydro-2H-benzo[1,4]oxazine derivatives as dual thromboxane A2 receptor antagonists and prostacyclin receptor agonists

We discovered a novel series of 3,4-dihydro-2H-benzo[1,4]oxazin-8-yloxyacetic acid derivatives as potent dual-acting agents to block the TXA2 receptor and to activate the PGI2 receptor. We report the synthesis, structure-activity relationship, and in vitro, ex vivo, and in vivo pharmacology of this series of compounds. 4-[2-(1,1-Diphenylethylsulfanyl)ethyl]-3,4-dihydro-2H-benzo[1,4]oxazin-8-yloxyacetic acid N-methyl-D-glucamine salt (7) is a promising candidate for a novel treatment in the anti-thrombotic and the cardiovascular fields avoiding hypotensive side effects.     

Discovery of thiochroman derivatives bearing a carboxy-containing side chain as orally active pure antiestrogens

In order to search for alternatives to the sulfoxide moiety in the long side chain of pure antiestrogens, several molecules that may interact with water in a fashion similar to ICI164,384 were designed and it was found that compounds with the carboxy, the sulfamide, or the sulfonamide instead of the sulfoxide moiety also functioned as pure antiestrogens. Interestingly, the compound possessing the carboxy moiety showed superior antiestrogen activity compared to ICI182,780 when dosed orally. Results of the pharmacokinetic evaluation indicated that the potent antiestrogen activity at oral dosing attributed to both the improved absorption from the intestinal wall and the metabolic stability of the compound in liver.     

Identification and characterization of the chemotactic transducer in Pseudomonas aeruginosa PAO1 for positive chemotaxis to trichloroethylene

Pseudomonas aeruginosa PAO1 is repelled by trichloroethylene (TCE), and the methyl-accepting chemotaxis proteins PctA, PctB, and PctC serve as the major chemoreceptors for negative chemotaxis to TCE. In this study, we found that the pctABC triple mutant of P. aeruginosa PAO1 was attracted by TCE. Chemotaxis assays of a set of mutants containing deletions in 26 potential mcp genes revealed that mcpA (PA0180) is the chemoreceptor for positive chemotaxis to TCE. McpA also detects tetrachloroethylene and dichloroethylene isomers as attractants.