Molecular characterization and determination of antimicrobial resistance of Mycoplasma gallisepticum isolated from chickens

In this study, three consecutive approaches of molecular characterization, determination of minimum inhibitory concentration (MIC) and antimicrobial tested on Mycoplasma gallisepticum (MG) isolated from chicken farms were investigated. These approaches were conducted between 2004 and 2005 to 134 MG samples collected from five different regions of the intensive farming area of Thailand. Twenty MG isolates and four reference strains including S6, F, ts-11, and 6/85 were classified according to Random Amplification of Polymorphic DNA (RAPD) patterns prior to the antimicrobial tests. These isolates exhibited 5 different genotypes (A-E). Consequently, MG isolates representing each genotype were tested on 11 registered antibiotics. The levels of MIC were determined. Three antibiotics, doxycycline (0.20 microg/ml), tiamulin (0.10 microg/ml), and tylosin (0.33 microg/ml), gave the least MICs among all effective drugs. Break point comparisons of each antimicrobial suggested that the MG isolates were most sensitive to lincomycin, oxytetracycline, tiamulin, and tylosin. Some MG isolates had an intermediate effect on josamycin and were resistant to enrofloxacin and erythromycin. Our results also indicated that MG isolated and collected from the region and nearby districts had similar RAPD patterns showing properties of antimicrobial resistance. The RAPD patterns may imply the frequent use of antibiotics and a resistant strain of MG. This is the first report of genetic characterization using RAPD reflected by the levels of MIC against MG. The information is useful to plan for prophylactic and therapeutic impacts on the poultry industry especially in the area of intensive use of antibiotics.     

Factors affecting respiration in dry pond bottom soils

The potential influence of drying, liming, tilling, bacterial augmentation, and nitrogen fertilization on respiration of pond bottom soil exposed to air between crops was evaluated in laboratory studies using soil respiration chambers. The optimum soil moisture concentration for respiration was 12–20%, and further drying decreased soil respiration. Soil respiration was greatest at pH 7.5–8.0, and both calcium hydroxide and calcium carbonate were effective in enhancing respiration of acidic soil. Pulverization of soil to eliminate the hard surface crust formed on drying accelerated respiration, thus tilling of pond bottom soils would be expected to increase respiration. Nitrogen fertilization showed some benefit to soil respiration, but there was no value in bacterial augmentation. These laboratory findings provide background information useful to pond studies on bottom soil treatments.     

泰国的蚕业现状与发展

通过对泰国蚕业全方位考察,了解了泰国桑园管理、农户养蚕、生丝生产、服装织造、蚕桑综合利用、农村技术培训和市场营销等多方面的情况;还了解了泰国的研究机构与泰国的蚕品种选育、桑品种选育、生丝天然染料植物资源等方面的研究进展情况;认为泰国蚕业稳中有升,但短期内发展速度不会太快。     

Anticancer Alkaloid Lamellarins Inhibit Protein Kinases

Lamellarins, a family of hexacyclic pyrrole alkaloids originally isolated from marine invertebrates, display promising anti-tumor activity. They induce apoptotic cell death through multi-target mechanisms, including inhibition of topoisomerase I, interaction with DNA and direct effects on mitochondria. We here report that lamellarins inhibit several protein kinases relevant to cancer such as cyclin-dependent kinases, dual-specificity tyrosine phosphorylation activated kinase 1A, casein kinase 1, glycogen synthase kinase-3 and PIM-1. A good correlation is observed between the effects of lamellarins on protein kinases and their action on cell death, suggesting that inhibition of specific kinases may contribute to the cytotoxicity of lamellarins. Structure/activity relationship suggests several paths for the optimization of lamellarins as kinase inhibitors.     

Within—country variation in the ability of ruminants to degrade DHP following the ingestion of Leucaena leucocephala—a Thailand experience

Goats fed Leucaena leucocephala (leucaena) at an experimental site in Thailand were shown to be excreting DHP in their urine. This was unexpected as earlier results from another site had shown that goats and cattle fed leucaena did not excrete DHP and so possessed DHP—degrading bacteria. Goats sampled near the earlier sample site excreted no DHP in their urine. Rumen fluid taken from these goats was successfully used to transfer DHP—degrading ability to the goats at the Experimental site some 350 km away that did not show the presence of DHP-degrading bacteria. Degradation of mimosine in-vitro and excretion of DHP in the urine ceased 72 hr after addition of rumen fluid and infusion with rumen fluid from protected goats, respectively. The situation in Thailand may not be unique. Countries where leucaena is fed should check that animals are protected. Fortunately, the ferric chloride urine test is simple to use and effective in detecting the problem and also the recovery after transfer of rumen fluid from protected animals.     

A study of nitrite-dependent dissimilatory micro-organisms isolated from oregon soils

Three specialized nitrite-dissimilatory microorganisms, found to be incapable of nitrate dissimilation, were isolated from Oregon soils. These isolates were designated as members of the genus Pseudomonas.Soil extracts stimulated nitrite dissimilation, with highest rates of activity observed with extracts from a manured soil. Nitrous oxide accumulation occurred with both nitrite- and oxygen-grown soil isolates during nitrite dissimilation in the presence of oxygen, whereas an isolate derived from a marine mud environment did not accumulate this intermediate when tested under comparative conditions.The soil-derived isolates were better able to adapt to changes between oxygen and nitrite as terminal electron acceptors, in comparison with the marine derived isolate. All isolates appeared capable of utilizing oxygen and nitrite simultaneously in their terminal respiration processes.Nitrous, but not nitric oxide was utilized as an electron acceptor by all isolates, and nitrite and nitrous oxide dissimilation was inhibited to varying degrees by cyanide, azide, and 2,4-dinitrophenol.Such infrequently studied specialized nitrite-dissimilating microorganisms, incapable of nitrate dissimilation, should be further investigated to better understand their role in nitrogen transformations, especially in manured soil environments.     

Comparative study of pandemic (H1N1) 2009, swine H1N1, and avian H3N2 influenza viral infections in quails

Quail has been proposed to be an intermediate host of influenza A viruses. However, information on the susceptibility and pathogenicity of pandemic H1N1 2009 (pH1N1) and swine influenza viruses in quails is limited. In this study, the pathogenicity, virus shedding, and transmission characteristics of pH1N1, swine H1N1 (swH1N1), and avian H3N2 (dkH3N2) influenza viruses in quails was examined. Three groups of 15 quails were inoculated with each virus and evaluated for clinical signs, virus shedding and transmission, pathological changes, and serological responses. None of the 75 inoculated (n = 45), contact exposed (n = 15), or negative control (n = 15) quails developed any clinical signs. In contrast to the low virus shedding titers observed from the swH1N1-inoculated quails, birds inoculated with dkH3N2 and pH1N1 shed relatively high titers of virus predominantly from the respiratory tract until 5 and 7 DPI, respectively, that were rarely transmitted to the contact quails. Gross and histopathological lesions were observed in the respiratory and intestinal tracts of quail inoculated with either pH1N1 or dkH3N2, indicating that these viruses were more pathogenic than swH1N1. Sero-conversions were detected 7 DPI in two out of five pH1N1-inoculated quails, three out of five quails inoculated with swH1N1, and four out of five swH1N1-infected contact birds. Taken together, this study demonstrated that quails were more susceptible to infection with pH1N1 and dkH3N2 than swH1N1.     

An analysis of isozymic loci polymorphism in the core collection of the Polish Pisum genebank

The investigated material consisted of the core collection of the Polish Pisum gene bank at Wiatrowo and represented a described, monohybrid variation (type lines for characters/genes and their initial lines, tester lines with markers and lines from wild taxa, 266 accessions in total). A polymorphism in 18 isozymic loci was analyzed (Lap-1, Px-1, Aat-p, Aat-m, Aat-c, Pgm-c, Pgm-p, Gpi-c, Idh, Acp-1, Skdh, Est-1, Est-2, Est-3, Aldo, 6Pgd-p, 6Pgd-c, Dia-1). The practical outcome of the analysis was a selection of lines with a high number of fast or slow isozymic alleles, useful as tester lines with markers for chromosome mapping. A polymorphism was stated in all investigated loci with 2 to 4 alleles ranging from very fast, fast, slow to very slow. Fast and slow alleles occurred in all loci. In 11 loci the incidence of fast alleles was higher than slow ones. Conversly, slow alleles occurred more frequently than fast ones in 5 loci. Additionally, there was a low incidence of a very fast allele in 7 loci and of a very slow allele in 3 loci. A slow allele was rare in 2 loci. Primitive lines and land races were a source of these rare alleles. It is suggested to consider a frequent allele of a given locus found in a group of wild lines as a so-called wild type of Pisum.     

Mantle transplantations in freshwater pearl mussels in Thailand

Allograft and xenograft mantle transplantations were studied in three species of freshwater pearl mussels, Hyriopsis (Limnoscapha) myersiana, H. (L.) desowitzi and Chamberlainia hainesiana, by transplanting foreign mantle tissue into the mantle tissue of a host mantle. The pearl sac is completely formed within 15 days after an allograft. After a xenograft from a C. hainesiana donor into a H. (L.) myersiana recipient, it took 13 days, and in the opposite case it took 15 days. For a H. (L.) desowitzi donor, it took 21 days in a C. hainesiana recipient and 27 days in a H. (L.) myersiana recipient. When the recipient was H. (L.) desowitzi, no pearl sac was observed after xenografts from either of the other two mussel species. Allografts of C. hainesiana and H. (L.) myersiana yielded the highest success rate of forming pearl sacs (96 and 97% respectively). Xenografts from a C. hainesiana donor into an H. (L.) myersiana recipient yielded 94%, and the opposite case yielded 90%. The first completed pearl layer was found for xenotransplantation into a C. hainesiana recipient from an H. (L.) myersiana donor at 126 days after transplantation.