Status of parasitism in donkeys of project and control areas in central region of Ethiopia: A comparative study

The study was undertaken with the aim of comparing the status of parasitism in donkeys in the Donkey Health and welfare Project intervention (Bereh, Ada and Boset) and Control (Yekaduda, Gerado and Meki) areas of, Central Ethiopia, in 2005. Parasites are prime problem of donkeys among other problems including wound and other infectious and noninfectious diseases. The methods applied included coproscopy, packed cell volume determination, live weight estimation and body condition scoring. A total of 648 donkeys were sampled from both control (324) and project (324) study areas. Qualitative faecal worm egg analysis revealed the prevalence of different helminthes in project and control areas to be respectively, Strongyles spp. (22.8% & 49.7%) , Oxyruis equi (4.6% & 6.5%), Anaplocephala spp. (2.2% &5.6%), Fasciola spp. (6.5% & 7.7%) and Gastrodiscus aegypticus (1.9% & 6.2%). The mean prevalence in the project and control areas was 22.9% and 29.0%, respectively. Quantitative faecal egg analysis revealed that the mean epg in the project and control areas to be 433.6 and 777.2 eggs per gram of faeces (epg), respectively. There was a significant difference (

Detection and determination of Oxytetracycline and Penicillin G antibiotic residue levels in bovine bulk milk from Nazareth dairy farms, Ethiopia

A cross-sectional study was conducted between October 2007 and May 2008 to detect and determine oxytetracycline and penicillin G residue levels in bulk milk of cows in Nazareth dairy farms. A total of 400 bulk milk samples were randomly collected. All samples were qualitatively screened for antibiotic residues by Delvotest SP assay. Questionnaire survey was carried out by personal interviews with some of the dairy farm owners in Delvotest positive farms (cases) and Delvotest negative farms (controls) to identify various risk factors for the occurrence of antibiotic residue in milk. Farm management practices, disease conditions and treatment factors have been identified as the main risk factors. Concentration of Oxytetracycline and Penicillin G in the positive samples was determined by High Performance Liquid Chromatography. Out of 400 samples analyzed for antibiotic residue, 48 (12 %) milk samples were positive for antibiotic residues. The mean residue level of oxytetracycline was 125.25μg/l and that of penicillin G was 4.52 μg/l. Concentrations of oxytetracycline and penicillin G in all samples were between ranges of 45 -192 μg/l and 0-28 μg/l, respectively. The antibiotic residue positive samples which showed residues of oxytetracycline above the WTO/FAO/ CAC established maximum residue limit of 100μg/l were 40 (83.33%). For penicillin G, the number of samples above the maximum residue limit of 4μg/l, were 8 (16.66%). In conclusion, this study revealed that oxytetracycline and penicillin G were imprudently used in dairy farms of the study area.Keywords: Delvotest SP, High Performance Liquid Chromatography, Milk, Oxytetracycline, Penicillin G, Residu

Uncovering Nematicidal Natural Products from Xenorhabdus Bacteria

Parasitic nematodes infect different species of animals and plants. Root-knot nematodes are members of the genus Meloidogyne, which is distributed worldwide and parasitizes numerous plants, including vegetables, fruits, and crops. To reduce the global burden of nematode infections, only a few chemical therapeutic classes are currently available. The majority of nematicides are prohibited due to their harmful effects on the environment and public health. This study was intended to identify new nematicidal natural products (NPs) from the bacterial genus Xenorhabdus, which exists in symbiosis with Steinernema nematodes. Cell-free culture supernatants of Xenorhabdus bacteria were used for nematicidal bioassay, and high mortality rates for Caenorhabditis elegans and Meloidogyne javanica were observed. Promoter exchange mutants of biosynthetic gene clusters encoding nonribosomal peptide synthetases (NRPS) or NRPS-polyketide synthase hybrids in Xenorhabdus bacteria carrying additionally a hfq deletion produce a single NP class, which have been tested for their bioactivity. Among the NPs tested, fabclavines, rhabdopeptides, and xenocoumacins were highly toxic to nematodes and resulted in mortalities of 95.3, 74.6, and 72.6% to C. elegans and 82.0, 90.0, and 85.3% to M. javanica, respectively. The findings of such nematicidal NPs can provide templates for uncovering effective and environmentally safe alternatives to commercially available nematicides

Global analysis of biosynthetic gene clusters reveals conserved and unique natural products in entomopathogenic nematode-symbiotic bacteria

Microorganisms contribute to the biology and physiology of eukaryotic hosts and affect other organisms through natural products. Xenorhabdus and Photorhabdus (XP) living in mutualistic symbiosis with entomopathogenic nematodes generate natural products to mediate bacteria-nematode-insect interactions. However, a lack of systematic analysis of the XP biosynthetic gene clusters (BGCs) has limited the understanding of how natural products affect interactions between the organisms. Here we combine pangenome and sequence similarity networks to analyse BGCs from 45 XP strains that cover all sequenced strains in our collection and represent almost all XP taxonomy. The identified 1,000 BGCs belong to 176 families. The most conserved families are denoted by 11 BGC classes. We homologously (over)express the ubiquitous and unique BGCs and identify compounds featuring unusual architectures. The bioactivity evaluation demonstrates that the prevalent compounds are eukaryotic proteasome inhibitors, virulence factors against insects, metallophores and insect immunosuppressants. These findings explain the functional basis of bacterial natural products in this tripartite relationship

Promoter Activation in Delta hfq Mutants as an Efficient Tool for Specialized Metabolite Production Enabling Direct Bioactivity Testing

Natural products (NPs) from microorganisms have been important sources for discovering new therapeutic and chemical entities. While their corresponding biosynthetic gene clusters (BGCs) can be easily identified by gene-sequencesimilarity-based bioinformatics strategies, the actual access to these NPs for structure elucidation and bioactivity testing remains difficult. Deletion of the gene encoding the RNA chaperone, Hfq, results in strains losing the production of most NPs. By exchanging the native promoter of a desired BGC against an inducible promoter in Dhfq mutants, almost exclusive production of the corresponding NP from the targeted BGC in Photorhabdus, Xenorhabdus and Pseudomonas was observed including the production of several new NPs derived from previously uncharacterized non-ribosomal peptide synthetases (NRPS). This easyPACId approach (easy Promoter Activated Compound Identification) facilitates NP identification due to low interference from other NPs. Moreover, it allows direct bioactivity testing of supernatants containing secreted NPs, without laborious purification