Differences of hyphal and soil phosphatase activities in drought-stressed mycorrhizal trifoliate orange (Poncirus trifoliata) seedlings

Differences of hyphal and soil phosphatase activities between mycorrhizal and non-mycorrhizal plants were less studied under drought-stressed (DS) conditions. In a pot experiment, fungal alkaline phosphatase (FALP), and succinate dehydrogenase (FSDH), soil phosphatase activity, both soil and plant P contents were compared in 6.5-month-old trifoliate orange (Poncirus trifoliata) seedlings under 80 days of DS with or without inoculations by arbuscular mycorrhizal fungi (AMF, Glomus diaphanum, Glomus mosseae or Glomus versiforme). Plant growth and biomass production under DS were significantly higher in mycorrhizal than in non-mycorrhizal seedlings. Both the FALP and the FSDH activities under DS were significantly reduced in these three Glomus inoculated seedlings. In general, similar soil neutral and alkaline phosphatase activities, but significantly higher soil acid and total phosphatase activities, were exhibited in mycorrhizal than in non-mycorrhizal seedlings under both the well-watered (WW) and the DS. Both leaf and root P contents were significantly higher in the AM colonized seedlings, but soil available P contents were lower in the growth media with AM seedlings. Our results showed that higher hyphal enzymes’ activities, soil acid and total phosphatase activities, and plant P contents in AM colonized seedlings, particularly in Glomus mosseae-colonized seedlings and/or under DS, would result in a better growth of the host plants, which might be the basis for enhancing drought tolerance in plants.     

Survival rate of airborne Mycobacterium bovis

Despite years of study the principle transmission route of bovine tuberculosis to cattle remains unresolved. The distribution of pathological lesions, which are concentrated in the respiratory system, and the very low dose of Mycobacterium bovis needed to initiate infection from a respiratory tract challenge suggest that the disease is spread by airborne transmission. Critical to the airborne transmission of a pathogenic microorganism is its ability to survive the stresses incurred whilst airborne. This study demonstrates that M. bovis is resistant to the stresses imposed immediately after becoming airborne, 94% surviving the first 10 min after aerosolisation. Once airborne the organism is robust, its viability decreasing with a half-life of approximately 1.5 hours. These findings support the hypothesis that airborne transmission is the principle route of infection for bovine tuberculosis.     

An all-island approach to mapping bovine tuberculosis in Ireland

This study used techniques in Geographical Information Systems (GIS) to explore the spatial patterns of bovine tuberculosis (TB) in the whole island of Ireland over an 11-year period. This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context. The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006. The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval.     

Anti-TB activity of Evodia elleryana bark extract

An ethyl acetate extract of bark from Evodia elleryana produced significant growth inhibition of Mycobacterium tuberculosis at concentrations only minimally inhibitory to human T cells. The crude extract yielded 95% inhibition of TB at 50 microg/ml. The crude extract yielded 29% growth inhibition of human T-cells in culture at that concentration.     

牛分枝杆菌重组蛋白TB27.4的表达、纯化及活性鉴定

为探索TB27.4蛋白在牛结核病鉴别诊断中的作用,本试验以牛分枝杆菌Vallee Ⅲ株基因组DNA为模板,PCR扩增tb27.4全长基因片段,将其定向克隆到原核表达载体pET-32a(+)中,构建重组质粒pET-TB27.4,优化原核表达条件,并用AKTA Purifier对蛋白的纯化条件进行优化。SDS-PAGE结果显示重组蛋白为可溶性表达,且大小与理论值相符,用牛分枝杆菌阳性血清进行Western blotting检测有特异性条带,且可特异性地刺激牛分枝杆菌感染牛外周血淋巴细胞释放大量IFN-γ。结果表明,重组蛋白TB27.4具有良好的B细胞活性和T细胞刺激活性,为进一步研究其在牛结核病诊断中的作用奠定了基础。