In vitro infection of aortic endothelial cells by caprine arthritis encephalitis virus enhances in vitro transmigration of peripheral blood leukocytes and modulates their phenotypic expression

Infection of goats by caprine arthritis-encephalitis virus (CAEV) provides a convenient example of the infiltration of various tissues by leukocytes following a natural lentiviral infection. This event is important in determining organ susceptibility and local immunity. Caprine vascular endothelial cells are susceptible to infection by CAEV in vitro, so we have investigated the consequences of this infection on the transmigration of uninfected leukocytes in an in vitro model. After in vitro infection by CAEV or stimulation by TNFalpha, the endothelial cells allowed the passage of tenfold more leukocytes from uninfected donors than did the uninfected endothelial cells. The transmigrating leukocytes were enriched in CD8+ lymphocytes, and the leukocytes appeared to have been activated during transmigration, as demonstrated by their expression of IL2R, MHC class II antigens and gamma-delta T-lymphocyte markers. CD4+, CD8+ and B-lymphocytes all proliferated in culture after transmigration. These results suggest that any possible infection or specific stimulation of endothelia in an infected animal could profoundly influence the choice of target organs and could activate the cells involved in local mucosal immune responses.     

Ultrastructural and Immunochemical Changes During the In Vitro Development of Plasmopara halstedii

ABSTRACT The asexual phase of the life cycle of Plasmopara halstedii, the causal agent of downy mildew of sunflower, plays a key role in the propagation of the disease. We investigated the morphological and ultrastructural changes that occur during the asexual development of the pathogen. Direct examination of infected cotyledons confirmed the presence of sporangiophores. In contact with water, important ultrastructural changes occurred, affecting the surface of zoosporangia, which became smoother, and their cytoplasm, which differentiated into flagellate zoospores. The subsequent encystment of zoospores was characterized by the synthesis of a cell wall and the loss of the flagella. In addition, two monoclonal antibodies (MAbs) specific for P. halstedii were used to analyze the immunochemical changes associated with these modifications. MAb 16A6, which bound to a 48-kDa glycoprotein, mainly labeled the surface of mobile or encysted zoospores and of mother cells of germ tubes. Conversely, MAb 2F9, which recognized highly glycosylated antigens, labeled the surface of zoosporangia and of flagellate zoospores, but not the encysted zoospores. These results provide new insights into the morphological and ultrastructural changes associated with the release and the encystment of zoospores which may be interesting targets for the development of new antimicrobial products.     

Use of an orally administered combined sugar solution to evaluate intestinal absorption and permeability in cats

OBJECTIVE: To evaluate intestinal permeability and absorption in healthy cats in association with diet and normal intestinal microflora. ANIMALS: 6 healthy domestic shorthair cats. PROCEDURE: A sugar solution containing D-xylose, 30-methyl-D-glucose, L-rhamnose, lactulose, and 51Cr-EDTA was administered intragastrically to healthy cats, and urinary excretion of ingested sugars was determined 5 hours after administration. After the same cats had received metronidazole for 1 month, the study was repeated. A final study was performed while cats were maintained on a new diet differing in composition and processing. RESULTS: Lactulose-to-rhamnose ratios, reflecting intestinal permeability, were higher in cats, compared with values for humans or dogs, and values obtained before and after metronidazole administration (mean +/- SEM; before, 0.40 +/- 0.08; after, 0.45 +/- 0.09) were not significantly different. Intestinal absorption also was unaltered after antibiotic administration, and the xylose-to-glucose ratio was 0.70 +/- 0.03 before and 0.71 +/- 0.06 after metronidazole administration. Sugar recovery did not differ significantly while cats were maintained on canned or dry food. CONCLUSIONS AND CLINICAL RELEVANCE: Reference ranges were established for the percentage urinary recovery of orally administered D-xylose, 3-0-methyl-D-glucose, L-rhamnose, lactulose, and 51Cr-EDTA obtained after 5 hours in healthy cats. The intestines of cats appear to be more permeable than those of other species, although the normal bacterial microflora does not appear to influence the integrity or function of the feline intestine, because values obtained for the measured variables before or after antibiotic administration were not significantly different. In addition, differences were not detected when the diet was completely altered.     

Effects of induced resistance on infection efficiency and sporulation of Puccinia striiformis on seedlings in varietal mixtures and on field epidemics in pure stands

An inducer race ofPuccinia striiformis inoculated two days before a challenger race on wheat seedlings of cv. Clement, reduced infection efficiency by 44% and lesion expansion by 7.7%; there was no effect on sporulation rate. In field epidemics, induced resistance restricted the disease intensity on cvs. Clement and Austerlitz in pure stands by 44% and 57% respectively. In the glasshouse at the seedling stage, disease intensity in a varietal mixture was reduced by 82% compared to the susceptible pure stands; one third of the total disease reduction was attributable to induced resistance.     

The hydroxyanilide fenhexamid,a new sterol biosynthesis inhibitor fungicide efficient against the plant pathogenic fungus Botryotinia fuckeliana (Botrytis cinerea)

Fenhexamid, a recently developed botryticide, is shown here to inhibit sterol biosynthesis. When the fungus Botryotinia fuckeliana was grown in the presence of fenhexamid, the ergosterol content was reduced, and three 3‐keto compounds, 4α‐methylfecosterone, fecosterone and episterone, accumulated, suggesting an inhibition of the 3‐keto reductase involved in C‐4 demethylation. Thus, fenhexamid belongs to a new, promising class of sterol biosynthesis inhibitors not previously used in agriculture or in medicine. © 2001 Society of Chemical Industry     

Effects of replacing fish meal with soy protein concentrate and of DL-methionine supplementation in high-energy, extruded diets on the growth and nutrient utilization of rainbow trout, Oncorhynchus mykiss

Our objectives were to test the potential replacement of fish meal by soy protein concentrate (SPC) in high-energy, extruded diets fed to rainbow trout (Oncorhynchus mykiss) and to evaluate the efficiency of DL-methionine supplementation of soy-based diets. Groups of trout (initial BW 103 to 106 g) were fed to visual satiety with isonitrogenous (6.6% DM) high-energy (22.8 MJ/kg DM gross energy), extruded diets, in which fish meal was progressively replaced with SPC (0, 50, 75, and 100%). Three 100% SPC diets were formulated to be either unsupplemented or supplemented with DL-methionine, so that total methionine content was .8 or 1.0% of DM. The quality of the SPC source used was assessed by measuring the antitryptic and antigenic activities and the concentrations of the isoflavones daidzein and genistein. Apparent digestibility of the diets was determined using the indirect method. A growth trial was conducted over 90 d at a water temperature of 18 degrees C. In addition to body composition analysis, plasma amino acid concentrations, anti-soy protein antibodies in the serum, and isoflavone concentrations in the bile were measured. The SPC source tested exhibited low antitryptic and antigenic activities, but it contained high concentrations of isoflavones (1,990 and 5,903 ppm for daidzein and genistein, respectively). Protein digestibility was high (92%) and was unaffected either the proportion of SPC in the diet or by DL-methionine supplementation. This was also true for the availability of amino acids, except phenylalanine. Digestibility of lipid and energy was reduced by 19% when SPC totally replaced fish meal. Growth rate was reduced when more than 50% of the dietary protein was of soy origin (daily growth coefficient of 3.2 and 2.1% for the control and the unsupplemented 100% SPC diet, respectively). The effect on growth was mainly explained by a general decline in feed intake (13.7 and 12.0 g DM x kg BW(-1) x d(-1) for the control and the unsupplemented 100% SPC diet, respectively) and in lipid and, thus, in energy digestibility. The DL-methionine supplementation partially reversed the depressive effects of high dietary SPC incorporation (+13% growth), mainly by enhancing intake. The negative effect of SPC incorporation either may be due to the high isoflavone concentration or to an interaction between the soy protein component and the dietary lipids.     

Rep-PCR Based Genomic Fingerprinting of Isolates of Leptosphaeria maculans from Poland

Leptosphaeria maculans, the ascomycete fungus which causes blackleg disease of oilseed rape, has been considered for a long time as a single species divided into aggressive and non-aggressive pathogenicity groups which differ in their economic importance. However, the development of accurate biochemical and molecular characterisation methods has demonstrated that the world-wide L. maculans population actually comprises at least two species. The aim of this research was to assess the ability of rep (repetitive element based)-PCR genomic fingerprinting methods, initially developed for bacterial identification, to characterise a collection of 90 isolates of L. maculans from Poland, in comparison with reference isolates from the IBCN (International Blackleg of Crucifers Network) collection. REP (repetitive extragenic palindromic)-, ERIC (enterobacterial repetitive intergenic consensus)-, and BOX primers for rep-PCR genomic fingerprinting, and primers derived from LMR1, a L. maculans specific repeated element, were tested. Rep-PCR and LMR1-based analyses were able to discriminate the different components of the species complex and to evaluate the genetic diversity within each member of the complex. These analyses suggested that Polish populations of L. maculans mainly belong to the non-aggressive species, rather than the aggressive species which is prevalent in Western Europe, Canada and Australia.     

Efficacy of selamectin in the treatment of naturally acquired cheyletiellosis in cats

The purpose of this study was to evaluate the efficacy of a topical formulation of selamectin in the treatment of cheyletiellosis in cats. Fifteen adult domestic cats from the same household with naturally occurring Cheyletiella sp. infestation were enrolled in the study. On each cat, 45 mg of selamectin was applied on days 0, 30, and 60. No other treatment or environmental decontamination was performed during the trial. On days 0, 30, 60, and 120, all cats were examined, epidermal debris was collected over the dorsal area of the body with flea combs for microscopic examination, and fecal flotations were done. Clinical signs had subsided by day 60 in all 15 cats and no signs of recurrence were apparent on follow-up 1 year later. All epidermal and fecal samples were negative by day 60. No adverse reactions were observed. Under the conditions of our study, topical selamectin was a practical and well-tolerated means of treatment for cheyletiellosis in cats.