46 research outputs found

    Ovine pedomics : the first study of the ovine foot 16S rRNA-based microbiome

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    We report the first study of the bacterial microbiome of ovine interdigital skin based on 16S rRNA by pyrosequencing and conventional cloning with Sanger-sequencing. Three flocks were selected, one a flock with no signs of footrot or interdigital dermatitis, a second flock with interdigital dermatitis alone and a third flock with both interdigital dermatitis and footrot. The sheep were classified as having either healthy interdigital skin (H), interdigital dermatitis (ID) or virulent footrot (VFR). The ovine interdigital skin bacterial community varied significantly by flock and clinical condition. The diversity and richness of operational taxonomic units was greater in tissue from sheep with ID than H or VFR affected sheep. Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria were the most abundant phyla comprising 25 genera. Peptostreptococcus, Corynebacterium and Staphylococcus were associated with H, ID and VFR respectively. Sequences of Dichelobacter nodosus, the causal agent of ovine footrot, were not amplified due to mismatches in the 16S rRNA universal forward primer (27F). A specific real time PCR assay was used to demonstrate the presence of D. nodosus which was detected in all samples including the flock with no signs of ID or VFR. Sheep with ID had significantly higher numbers of D. nodosus (104-109 cells/g tissue) than those with H or VFR feet

    Multiple Mating and Family Structure of the Western Tent Caterpillar, Malacosoma californicum pluviale: Impact on Disease Resistance

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    Background Levels of genetic diversity can strongly influence the dynamics and evolutionary changes of natural populations. Survival and disease resistance have been linked to levels of genetic diversity in eusocial insects, yet these relationships remain untested in gregarious insects where disease transmission can be high and selection for resistance is likely to be strong. Methodology/Principal Findings Here we use 8 microsatellite loci to examine genetic variation in 12 families of western tent caterpillars, Malacosoma californicum pluviale from four different island populations to determine the relationship of genetic variability to survival and disease resistance. In addition these genetic markers were used to elucidate the population structure of western tent caterpillars. Multiple paternity was revealed by microsatellite markers, with the number of sires estimated to range from one to three per family (mean ± SE = 1.92±0.23). Observed heterozygosity (HO) of families was not associated to the resistance of families to a nucleopolyhedrovirus (NPV) (r = 0.161, F1,12 = 0.271, P = 0.614), a major cause of mortality in high-density populations, but was positively associated with larval survival (r = 0.635, F1,10 = 5.412, P = 0.048). Genetic differentiation among the families was high (FST = 0.269, P<0.0001), and families from the same island were as differentiated as were families from other islands. Conclusion/Significance We have been able to describe and characterize 8 microsatellite loci, which demonstrate patterns of variation within and between families of western tent caterpillars. We have discovered an association between larval survival and family-level heterozygosity that may be relevant to the population dynamics of this cyclic forest lepidopteran, and this will be the topic of future work

    Isolation, identification and evaluation of antimicrobial activity of streptomyces flavogriseus, strain actk2 from soil sample of Kodagu, Karnataka state (India)

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    Background: The search for novel antibiotics continues to be of immense importance in research programs around the world for pharmaceutical, industrial and agricultural applications. Filamentous soil bacteria, belonging to the Streptomyces genus, are widely used as an important biological tool for their ability to produce a wide range of novel secondary metabolites, such as ``antibiotics''. Objectives: The aim of the present study was to isolate and identify a strain of Streptomyces with high antibiotic production capability. Materials and Methods: The soil sample was collected randomly from the agricultural land of Kushalnagar Taluk of Kodagu district, Karnataka, India. The ACTK2 strain was isolated by serial dilution method and identified based on cultural, morphological, microscopic, biochemical and sequence analysis of 16S rRNA gene parameters. The isolated ACTK2 was analyzed for antimicrobial activities by perpendicular streak and disc diffusion methods, against the Gram-positive bacteria Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 121), Gram-negative Escherichia. coli (MTCC 729), Enterococcus aerogenes (MTCC 2829) and filamentous fungi (Trichoderma harizianum (MTCC6046), Fusarium proliferatum (MTCC 9375). Further, an antimicrobial metabolite from the ACTK2 strain was extracted by solvent extraction method, using n-butanol. The production of the antimicrobial compound by the ACTK2 strain was optimized by using different nutritional media and cultural conditions. Results: The strain Streptomyces flavogriseus designated as ACTK2 (Accession number KC990785) isolated from the soil sample of Kushalnagar Taluk, Kodagu, Karnataka, India, exhibited a broad spectrum of antimicrobial activity against test microorganisms. The optimum growth and antimicrobial compound production by strain ACTK2 was found to be a maximal pH 8, in the shaker incubator at 28 degrees C, for a period of 10 days. Conclusions: The crude n-butanol extract of the ACTK2 strain of S. flavogriseus showed a broad spectrum of antimicrobial activities against the test organisms and this opened further research investigations on purification and structural characterization of the active compounds from the crude extract
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