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Aminograms of tubal and follicular fluids were obtained using fluids collected by aspiratory puncture from six cats. The amino acids were separated and quantified by high-performance liquid chromatography analysis. The serum of the cats was used as control. The three most prevalent amino acids quantified in cat tubal fluid were glycine, glutamic acid, and taurine. Their mean concentrations were 840 μmol/l (μm), 808 μm and 596 μm, respectively. The three most prevalent amino acids quantified in cat follicular fluid were alanine, glutamine, and taurine. Their mean concentrations were 359 μm, 351 μm, and 258 μm, respectively. This result is consistent with aminograms of tubal fluid previously determined in other mammals. As previously observed in other species and humans, glycine was quantitatively the most abundant and most prevalent free amino acid in cat tubal fluid. The total quantity of amino acids in tubal fluid was similar in cats and other species. However, in contrast with other species studied, hypotaurine was not detected in tubal and follicular fluids of female cats., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Concanavalin A (lectin from Canavalia ensiformis L., ConA) has previously been shown to act as a feeding inhibitor for Acyrthosiphon pisum, the pea aphid. In the present study a range of histochemical and biochemical techniques were used to elucidate the target tissues and binding sites of the lectin in the aphid. Diet uptake was evaluated using a radioactive tracer (14C-methylated inulin) and demonstrated that adults were capable of ingesting high quantities of the toxin (approx. 1 microg over a 48 h period). Electophoretic analysis and enzyme-linked immuno-sorbent assay of honeydew samples confirmed these results and further demonstrated that only small levels of ConA were excreted. Histofluorescence and immunolocalisation studies on nymphs revealed that the stomach was the primary target for ConA. At concentrations up to 400 microg ml(-1), lectin binding only occurred in the stomach region, however, at high concentrations (800 microg ml(-1)) the whole digestive tract was stained, although there was no evidence of binding in either the oesophagus or rectum. In addition to binding, there was evidence to suggest that ConA was also causing systemic effects in that the lectin appeared to cross the intestinal epithelial barrier. Immunohistochemical and electron microscopy studies revealed that ConA induced severe cellular swelling of the epithelial cells, accompanied by hypersecretion and a progressive detachment of the apical membrane; however, the striated border itself did not appear to be directly affected. Furthermore, there was no lysis of the epithelium, nor loss of integrity of the epithelial cells themselves. Our results suggest that ConA interacts with glycosylated receptors at the surface of the stomach epithelial cells, interfering with normal metabolism and cell function, resulting in a rapid feedback response on feeding behaviour. Whilst our results provide a much greater understanding regarding the modes of action of ConA in insects, they suggest that different lectins, including other mannose binding lectins, have different modes of action at the cellular levels, and thus generalizations should be treated with caution.

Aphidius ervi Haliday (Hymenoptera, Braconidae) is an endophagous parasitoid of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera, Aphididae). This parasitoid strongly redirects host reproduction and metabolism to favour nutrition and development of its juvenile stages. Parasite-regulated biosynthesis and mobilization of nitrogen metabolites determine a significant increase of host nutritional suitability. The aim of the present study was mainly to investigate the temporal changes of A. pisum amino acid pools, as affected by A. ervi parasitism, and to assess the role of the aphid bacterial endosymbiont Buchnera in determining the observed changes. In parasitized aphids, we observed a very significant increase in total free amino acids, compared with synchronous non-parasitized controls, starting from day 4 after parasitization (+51%). This trend culminated with more than doubling the control value (+152%) on day 6 after parasitization. However, a significant "parasitism" effect was observed only for 10 of the 28 amino acids detected. Tyrosine accumulation was the most prominent parasitoid-induced alteration, with a fourfold increase over control levels registered on day 6. In parasitized hosts, the amino acid biosynthetic capacity of Buchnera was unaltered, or even enhanced for the phenolic pool, and contributed greatly to the definition and maintainance of host free amino acid pools. The hypertyrosinemic syndrome was not dependent on food supply of the aromatic nucleus but was induced by parasitism, which likely enhanced the aromatic shuttle mediating phenylalanine transfer from bacteria to the host tissues, where tyrosine conversion occurs. This process is likely associated with a selective disruption of the host's functions requiring tyrosine, leading to the remarkable accumulation of this amino acid. The possible mechanisms determining these parasitism-induced host alterations, and their nutritional significance for the developing parasitoid larva, are discussed.

Flow radioactivity counters coupled to liquid chromatography devices cause a systematic bias to the separation by broadening peaks within the radiochromatogram. Such signal smearing may be evaluated on standardization runs with a single peak, using the ratio between Fourier transforms of whole chromatographic data for the measured radioactivity time series (radioactivity channel) and for the concentration time series (optical density channel). This ratio constitutes a kernel suitable to perform the deconvolution of any radiochromatogram performed under similar conditions. Through deconvolution, the signal smearing is removed, reverting to peaks with the same geometry as in the concentration chromatogram: same retention time, peak width, and shape. The deconvolution method in processing radiochromatograms allows an easier interpretation and gives more reliable radioactivity quantification (improved linearity of the measured response). Fourier transformation of the radiochromatogram also allows the removal of transitory events (noise) through the correlation procedure. This method may provide substantial gain in sensitivity, depending upon the residence time of the sample in the counting cell.

We previously demonstrated that the translocation of phospholipids between the mitochondrion and the endoplasmic reticulum occurs via highly specialized membrane microdomains of both organelles that are in situ closely associated. As understanding of the interactions between both organelles requires characterization of the translocation sites organization, we first analysed the amino acid compositions of these sites. Using principal component analysis, we have shown that the translocation sites exhibit characteristic patterns when compared with the membranes from which they are derived. The results are discussed in terms of both functional and structural microcompartmentation within the membranes of mitochondria and endoplasmic reticulum.