Role of DNA repair in Bacillus subtilis spore resistance.

Wet-heat or hydrogen peroxide treatment of wild-type Bacillus subtilis spores did not result in induction of lacZ fusions to three DNA repair-related genes (dinR, recA, and uvrC) during spore outgrowth. However, these genes were induced during outgrowth of wild-type spores treated with dry heat or UV. Wet-heat, desiccation, dry-heat, or UV treatment of spores lacking major DNA-binding proteins (termed alpha-beta- spores) also resulted in induction of the three DNA repair genes during spore outgrowth. Hydrogen peroxide treatment of alpha-beta-spores did not result in induction of dinR- and rerA-lacZ but did cause induction of uvrC-lacZ during spore outgrowth. Spores of a recA mutant were approximately twofold more UV sensitive and approximately ninefold more sensitive to dry heat than were wild-type spores but were no more sensitive to wet heat and hydrogen peroxide. In contrast, alpha-beta- recA spores were significantly more sensitive than were alpha-beta- spores to all four treatments, as well as to desiccation. Surprisingly, RecA levels were quite low in dormant spores, but RecA was synthesized during spore outgrowth. Taken together, these data (i) are consistent with previous suggestions that some treatments (dry heat and UV with wild-type spores; desiccation, dry and wet heat, hydrogen peroxide, and UV with alpha-beta- spores) that kill spores do so in large part by causing DNA damage and (ii) indicate that repair of DNA damage during spore outgrowth is an important component of spore resistance to a number of treatments, as has been shown previously for UV.     

凝结芽胞杆菌TBC 169株对肠道致病菌的抑菌作用

目的 研究凝结芽胞杆菌TBC 169株对大肠埃希菌、痢疾志贺菌、伤寒沙门菌、普通变形杆菌、铜绿假单胞菌和金黄色葡萄球菌的抑制作用。方法 先将大肠埃希菌、痢疾杆菌等6种菌分别进行单独培养,测定不同培养时间内的pH和活菌数,然后将凝结芽胞杆菌TBC 169株分别和致病菌进行混合培养,再测pH和活菌数,并与单独培养时的测定情况进行比较。结果 凝结芽胞杆菌TBC 169株对大肠埃希菌、痢疾志贺菌、伤寒沙门菌等6种菌均有明显的抑制作用,尤其是对伤寒沙门菌和铜绿假单胞菌的抑制作用更强。结论 凝结芽胞杆菌TBC 169株对肠道致病菌有显著的抑制作用。     

Independence of Bacillus subtilis spore outgrowth from DNA synthesis.

The outgrowth of spores of Bacillus subtilis 168 proceeded normally in temperature-sensitive DNA mutants under restrictive conditions and in the absence of DNA synthesis. Two inhibitors of DNA synthesis, nalidoxic acid and 6-(p-hydroxyphenylazo)-uracil, inhibited spore outgrowth under some nutritional conditions; this inhibition of outgrowth however, though not that of DNA synthesis, could be reversed by glucose. The sensitivity of the outgrowing spores to nalidixic acid and 6-(p-hydroxyphenylazo)-uracil inhbition decreased as a function of outgrowth time. The cells became completely resistant to the inhibitors after 90 min. The development of this resistance occurred also in the absence of DNA synthesis. It was concluded that DNA synthesis is not needed for spore outgrowth, and that outgrowing cells and vegetative cells differ in their sensitivity to these inhibitors.     

Surfactin isoforms from Bacillus coagulans

Bacillus coagulans has been found to produce several surfactins that are powerful lipopeptide surfactants. Four main components with molecular weights 1007, 1021 and 1035 Da were separated. Their structures have been confirmed by spectrometric and spectroscopic studies and by acid hydrolysis. The compounds were found to represent two pairs of surfactin isoforms in which beta-hydroxy-iso-C14 or anteiso-C15 fatty acids are linked to the [Leu7] or [Val7] heptapeptide moiety by both an amide group and a lactone bond.     

凝结芽孢杆菌在动物饲料中的应用

随着我国“饲料禁抗, 养殖减抗”政策的实施, 饲料及动保企业都在寻找合理有效的抗生素替代品。目前, 人们对以凝结芽孢杆菌为主的饲用微生态制剂进行了很多的实证试验, 替抗效果也逐渐得到行业认可。凝结芽孢杆菌拥有乳酸菌和芽孢菌的双重特性, 能耐受饲料制粒温度存活, 到达胃肠道后萌发并分泌代谢产物, 最终促进畜禽的肠道健康。本文对凝结芽孢杆菌的生物学特性和生物学功能进行阐述, 总结了近年来凝结芽孢杆菌在畜禽、水产和生物饲料中的应用研究, 以期为凝结芽孢杆菌在畜牧养殖中的合理应用提供参考。

     

Growth of Bacillus coagulans in Chemically Defined Media

A nutritional study was made of five strains of Bacillus coagulans obtained from various culture collections. These five strains were descendants of two original isolates; three had been derived from one parent culture in years past and the other two were transfers from another parent culture. Therefore, the five cultures should have represented two distinct groups of genetically identical cultures. Three of the strains obtained from one culture collection had become methyl red-negative and sorbitol-negative and had gained abilities to hydrolyze gelatin and ferment arabinose. Nutritional requirements of the five cultures, determined at 37, 45, and 55 C, differed considerably among strains; however, thiamine and biotin were required by all cultures at all temperatures. Aspartic acid was stimulatory at 37 C and was required at 45 C; folic acid, basic amino acids, and certain other nutrilites were required at 55 C. Adenine supplementation was necessary for two strains at 55 C to prevent autolysis; this phenomenon is discussed. The response of these organisms to both serine and the basic amino acids at the three growth temperatures seems especially significant. The media devised for the growth of the five strains of B. coagulans used in this study permit excellent growth at three incubation temperatures.     

一株凝结芽胞杆菌的筛选及对肉鸡生产性能的影响

目的分离自然界中可安全应用于畜禽的凝结芽胞杆菌,提高肉鸡的饲料消化吸收、降低料肉比,改善生产性能。方法在山上、海边及樱桃树下的土壤中分离凝结芽胞杆菌,通过生理生化、16S rRNA鉴定研究菌株的生物学特性,并考察其安全性;最终应用于促进饲料消化吸收、保护肠道健康、提高生产性能。肉鸡饲养至第31天时开始添加凝结芽胞杆菌10 d,分为实验组(1、2、3组)和对照组,考察生产性能指标确定其功能。结果凝结芽胞杆菌J-1产酸溶钙圈高于其他2株,为革兰阳性菌。实验表明在同样的养殖条件下,实验组鸡的粪便干燥、成型、无酱黄色出现;实验组鸡苗的前期7日龄时体质量低于对照组,肉鸡的成活率分别高于对照组0.9%、0.7%、1.2%,料肉比分别低于对照组0.066、0.080、0.050,出栏均重分别优于对照组0.144 kg、0.129 kg、0.079 kg。结论筛选出1株安全、产酸且应用肉鸡实际效果优良的凝结芽胞杆菌,可降低肉鸡料肉比,提高肉鸡的出栏均重、成活率、饲料利用率,并减少肉鸡养殖后期抗生素的使用。     

The Bacillus anthracis spore

In response to starvation, Bacillus anthracis can form a specialized cell type called the spore, which is the infectious particle for the disease anthrax. The spore is largely metabolically inactive and can resist a wide range of stresses found in nature. In spite of its dormancy, the spore can sense the presence of nutrient and rapidly return to vegetative growth. These properties help the spore to persist for long periods of time in the environment, survive host defenses after entering the body, and cause disease when the correct location in the host is reached. The anatomy of the spore is unique among bacteria, being comprised of a series of specialized concentric shells, each of which provides specific critical functions. Surrounding the spore core (which houses the chromosome) is a peptidoglycan layer important for spore dormancy, a protein shell that resists a variety of toxic molecules, and finally an exterior protein and glycoprotein layer that, among other functions, mediates interactions with surfaces, including those encountered by the spore within the host. Detailed molecular analysis of these shells has shed considerable light on how each layer determines specific spore properties. Future work, especially on the outermost spore layer, is likely to advance therapeutics, methods for spore decontamination and other critical biodefense technologies.