Comparison of α-acetolactate synthase and α-acetolactate decarboxylase in Lactococcus spp. and Leuconostoc spp.

Summary Cell-free extracts of Leuconostoc and Lactococcus species were tested for their -acetolactate synthase and -acetolactate decarboxylase activities. In Leuconostoc mesenteroides subsp. cremoris, Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc lactis, the Km of -acetolactate synthase for pyruvate was close to 10 mM whereas it was 30 mM in Lactococcus lactis subsp. lactis biovar. diacetylactis. The Km of -acetolactate decarboxylase for -acetolactic acid was very low (0.3 mM) in Leuconostoc species in comparison to Lactococcus lactis subsp. lactis biovar. diacetylactis (60 mM). In the latter bacterium, -acetolactate decarboxylase showed a sigmoidal dependance upon -acetolactic acid and was activated by the three branchedchain amino acids: leucine, isoleucine and valine.     

The Production of β-Fructofuranosidase from Bifidobacterium spp.

The productions of β-fructofuranosidase from Bifidohacterium longum A1, B. adolescentis G1, and four other strains of Bifidobacteria were investigated. All strains used in this study were grown in modified BL broth containing a mixture of fructooligosaccharides [1^F (1-β-D-fructofuranosyl)_n-1sucrose, GF_n (n = 2 – 5)] as the only carbon source. Hydrolyses of 1-kestose, sucrose, and inulin were detected in the extract of the cell. The highest activity on 1-kestose was detected in the extract of B. longum A1 followed by B. adolescentis G1. The other extracts weakly attacked 1-kestose. The relative activities of the extract of B. adolescentis G1 for 1-kestose, nystose, 1^F-fructosylnystose, sucrose, and inulin were 100, 82.5, 50.8, 28.3, and 15.0, respectively. The relative activities for various substrates differed from invertases (yeast β-fructofuranosidases) and exo-inulinase from Penicillium trzehinskii.     

食蚊鱼（Gambusia spp.）入侵生态学研究进展

食蚊鱼(Gambusia spp.)是原产于北美洲的著名入侵物种,它对蚊类幼虫具有很强的捕食压力,被作为疟疾防治生物工具而在全世界温带和热带地区扩散.近20多年来的研究认为,食蚊鱼通过食物竞争和捕食等机制威胁引入地的无脊椎动物、鱼类、两栖类的生存,显著影响引入地的生物多样性.它们具有广泛的生境适应性、生长迅速、卵胎生、高生殖率、对生殖生态条件无特殊要求等特点.另外,它们的个体野外寿命不超过2a,种群更新速度快,种群内形成春季和夏季两个繁殖群体,并具有不同的繁殖生物学特点,因而形成复杂的世代结构.遗传上,雌鱼具有混交及能长期贮存精子的特点,能快速建立种群并克服奠基效应.这些种群通过快速适应性进化而形成一定规模的地理群体.当前,由于食蚊鱼在预防疟疾的工作中仍具有不可替代的作用,它会借助于人力的作用而继续扩散.为减轻它对非目标地区和非目标生物的影响,应进一步深入开展其入侵生态学研究.     

Nucleoids and coated vesicles of “Epulopiscium” spp.

We describe here aspects of the anatomy of two “Epulopiscium” morphotypes, unusually large bacteria that are not yet cultured and that reproduce by the internal generation of two or more vegetative daughter cells. Two morphotypes, A and B, which are enteric symbionts of several species of herbivorous surgeonfish (Acanthuridae), were collected around the Great Barrier Reef of Australia, preserved there, and later stained for light microscopy. Some samples were examined by electron microscopy. In both morphotypes, countless discrete nucleoplasms or nucleoids were found to occupy a single shallow layer just beneath the surface all around these organisms. At each end of the morphotype B cells, a membrane-bound compartment containing dense cords of chromatin was observed. When these were found at each end of growing daughter cells, no polar compartments were then found in their mother organism. Electron micrographs of sections of morphotype A symbionts show that their outermost region is composed of tightly packed coated vesicles, each surrounded by a thin, dense, spacious capsule. Near the surface of type A organisms the remains of broken vesicles, broken capsules, and a finely fibrous matrix fuse to form a fabric that serves as the cell wall. Morphotype B organisms, however, were observed to have a distinct, morphologically continuous outer wall. Received: 3 December 1997 / Accepted: 11 June 1998     

Prévalence d'Aeromonas spp. dans les gastro-entérites de l'enfant.

A selective medium and biochemical tests were used to search for Aeromonas spp. in the stools of 536 children, more than 90% of whom had "gastroenteritis", seen at Sainte-Justine Hospital, Montreal, in June or July 1986. The organism was found in seven children, six of whom had bloody diarrhea. One of the six, a 6 1/2-year-old boy, required intravenous alimentation and later manifested ulcerative colitis; the other five recovered. The remaining child, a 14-year-old boy, had synovitis of the knee and spondylarthritis. Two of the seven carried other enteric pathogens. The authors discuss the pathogenicity of Aeromonas spp., which is not very marked in temperate climates, in human summer diarrhea and its possible role in the development of ulcerative colitis.     

‘Seed’ production of Porphyra spp. by tissue culture

Differentiation of archeospores was observed from excised tissue of young thalli of various monoecious Porphyra species ( P. tenera, P. yezoensis, P. suborbiculata, P. okamurae) after 4–8 days in culture at temperatures of 20 and 25 °C. Excised tissue from adult thalli did not differentiate into archeospores, but rather regenerated directly into blades and rhizoids of foliose thalli. Tissues from young thalli of two dioecious Porphyra species ( P. dentata and P. pseudolinearis) also regenerated into blades and rhizoids after manipulation of the culture conditions. In addition, 1–2 celled tissue pieces of both monoecious and dioecious species were also seen to develop directly into blades. Polarity of regeneration of blades and rhizoids was observed in these species. These results suggest that ‘seed’ can be obtained through tissue culture instead of using conventional conchocelis culture for commercial nori aquaculture in Japan. This revised version was published online in June 2006 with corrections to the Cover Date.     

Identification of Staphylococcus spp. using (GTG)₅-PCR fingerprinting

A group of 212 type and reference strains deposited in the Czech Collection of Microorganisms (Brno, Czech Republic) and covering 41 Staphylococcus species comprising 21 subspecies was characterised using rep-PCR fingerprinting with the (GTG)₅ primer in order to evaluate this method for identification of staphylococci. All strains were typeable using the (GTG)₅ primer and generated PCR products ranging from 200 to 4500 bp. Numerical analysis of the obtained fingerprints revealed (sub)species-specific clustering corresponding with the taxonomic position of analysed strains. Taxonomic position of selected strains representing the (sub)species that were distributed over multiple rep-PCR clusters was verified and confirmed by the partial rpoB gene sequencing. Staphylococcus caprae, Staphylococcus equorum, Staphylococcus sciuri, Staphylococcus piscifermentans, Staphylococcus xylosus, and Staphylococcus saprophyticus revealed heterogeneous fingerprints and each (sub)species was distributed over several clusters. However, representatives of the remaining Staphylococcus spp. were clearly separated in single (sub)species-specific clusters. These results showed rep-PCR with the (GTG)₅ primer as a fast and reliable method applicable for differentiation and straightforward identification of majority of Staphylococcus spp.     

Bacillus spp.的筛选鉴定及浸矿渣效果研究

目的:研究Bacillus spp.的生长特性及浸镉渣效果。方法:采用9K培养基划线分离纯化目标菌种,利用传统的测定方法测定其生长特征,采用16S rDNA对菌株进行分子生物学鉴定,最后对该菌株浸三种矿渣浸出效果进行了分析。结果:该微生物形态为扁球形,革兰氏染色呈阳性,能运动,单生鞭毛;最适生长温度30℃,最适pH值为3;代谢类型为兼性营养型;耐受NaCl浓度为4%;微生物氧化酶为阴性,接触酶为阳性;经鉴定该菌株属于Bacillus属。以5%的接种量,培养基pH为3条件下,镉浸出效果较好,沉渣中浸出率为90.4%,其余两种渣中浸出效果最佳。结论:Bacillus spp.可应用于镉渣中镉的浸出。     

散斑壳属Lophodermium spp.ITS区的序列分析

在国内首次对散斑壳属两个代表种的rRNA基因内转录间区(ITS区)进行了克隆测序,并与Genbank中已有的有关序列进行了比较。发现散斑壳属种间的遗传差异明显高于种内的遗传差异,这与形态学分类相符合,表明ITS区序列分析与形态学鉴定相结合的方法用于散斑壳属的分类研究是可行的。     

Application of AFLP™-based molecular markers to breeding of Populus spp.

Molecular marker technologies have eased and potentiated genetic analysis of plants and have become an extremely useful tool in forest tree breeding. The information provided by molecular markers has made it possible to acquire further knowledge about the structure and organization of plant genomes as well as about the evolution of these plant genomes through phylogenetic analysis. Using Populus spp. as a model tree, this paper aims at showing and discussing the possible applications of AFLP, a high-density DNA marker technology developed by Keygene N.V. (Wageningen, The Netherlands). Applications include: (i) AFLP analysis of the disease resistance against Melampsora larici-populina using bulked-segregant analysis, (ii) AFLP fingerprinting for identification and taxonomic analysis of individual trees, and (iii) AFLP-based mapping strategies in Populus.Abbreviations AFLP amplified fragment length polymorphism - RFLP restriction fragment length polymorphism - PCR polymerase chain reaction - QTL quantitative trait loci - RAPD random amplified polymorphic DNA     

Does Phaeocystis spp. contribute significantly to vertical export of organic carbon?

Phaeocystis spp. cell and colony mass fluxes and their contribution to the vertical particulate organic carbon (POC) export from a wide range of stations were quantified by short-term sediment traps. The compilation of available data, ranging from polar to sub-arctic and boreal regions, revealed that Phaeocystis colonial and single cells frequently are observed in shallow sediment traps at 30–50 m depth (average of 7 ± 11% of POC export). A strong vertical export decline between 40 m and 100 m diminished the contribution of Phaeocystis spp. cell carbon to vertical export of POC to only 3 ± 2% at 100 m depth, with two exceptions (deeper mixed stations). Estimates of potential corresponding mucus contribution increased the average Phaeocystis spp. contribution to <5% of POC export. The vertical flux attenuation efficiency is higher for Phaeocystis spp. than for diatoms. The overall contribution of Phaeocystis spp. to vertical carbon export based on direct investigations of vertical organic carbon export is small.     

Can Lactobacillus spp. Be a Factor Reducing the Risk of Miscarriage?

Pregnancy loss is a common obstetric problem. Significant causes of miscarriage include genetic and epigenetic disorders of the embryo, immunological and endocrine factors, uterine malformations, improper embryo selection, and lifestyle. Perhaps a hitherto underappreciated cause of miscarriage may be an abnormal microbiota composition of the female reproductive system. Lactobacillus spp. is the most common bacteria within the reproductive tract. However, the protective role of Lactobacilli in the vagina has been well described in the literature, while it is still unknown what function Lactobacilli may have in the uterus. Moreover, new research shows that Lactobacillus spp. can have a role in miscarriage. However, both molecular and immunological mechanisms of host-Lactobacillus spp. interactions are not fully understood. Understanding these relationships will help address the importance and extent of the protective role of Lactobacillus spp. in miscarriage.     

Pyrene Biodegradation by Bacillus spp. Isolated from Coal Tar–Contaminated Soil

Aerobic, mesophilic bacteria from coal tar–contaminated soil were analyzed for pyrene utilization capacity and identified by 16S ribosomal DNA sequencing as members of three genera: Bacillus spp., Pseudomonas sp., and Rhodococcus sp. The soil contained nine different hazardous polyaromatic hydrocarbons (PAHs): benzo[g, h, i]perylene, dibenzo[a, h]anthracene, indeno[1,2,3-c,d]pyrene, pyrene, acenaphthylene, fluorene, phenanthrene, benzo[k]fluoranthene, and benzo[b]fluoranthene. Bacillus spp. (PK-6) MTCC 1005 showed 56.4% utilization of pyrene (C₁₆H₁₀) (50 μg ml^?1) in 4 days, with growth associated biosurfactant activity and resulted in the formation of five new intermediates: phenanthrene (C₁₄H₁₀), 9,10-diphenylphenanthrene (C₂₆H₁₈), 9-methoxyphenanthrene (C₁₅H₁₂O), 5,6,7,8-tetrahydro-1-naphthoic acid (C₁₁H₁₂O₂), and 1,6,7-trimethylnaphthalene (C₁₃H₁₄). The results suggested that Bacillus spp. could be found suitable for practical field application for effective in situ PAH bioremediation.     

Enterobacter spp.：引起“桑枯萎”病的新证据

从浙江省杭州地区＂桑枯萎＂病树上分离获得36株病原细菌,通过对6株代表菌的常规细菌学、电子显微镜观察、致病性及Koch氏假说测定、Biolog鉴定、脂肪酸分析、生理生化、ERIC-PCR（enterobacterial repetitive intergenic consensus-PCR）分析、16S rRNA序列分析,同时与肠杆菌属（Enterobacter）中与植物有关的7个模式种菌株和其他3株参考菌株的比较,确认＂桑枯萎＂病为肠杆菌属中1个以上的新种（Enterobacter spp.）所引起.＂桑枯萎＂病是一种国内外尚未报道的桑树新病害,是Enterobacter spp.引起植物病害的又一新证据.该研究结果不但对桑树病害的治理具有实际意义,而且对深入研究Enterobacter中的人体条件致病菌及环保菌具有重要的学术价值。     

Enterobacter spp.:引起“桑枯萎”病的新证据

从浙江省杭州地区"桑枯萎"病树上分离获得36株病原细菌,通过对6株代表菌的常规细菌学、电子显微镜观察、致病性及Koch氏假说测定、Biolog鉴定、脂肪酸分析、生理生化、ERIC-PCR(enterobacterial repetitive intergenic consensus-PCR)分析、16S rRNA序列分析,同时与肠杆菌属(Enterobacter)中与植物有关的7个模式种菌株和其他3株参考菌株的比较,确认"桑枯萎"病为肠杆菌属中1个以上的新种(Enterobacter spp.)所引起."桑枯萎"病是一种国内外尚未报道的桑树新病害,是Enterobacter spp.引起植物病害的又一新证据.该研究结果不但对桑树病害的治理具有实际意义,而且对深入研究Enterobacter中的人体条件致病菌及环保菌具有重要的学术价值。     

侧沟茧蜂Microplitis spp .搜寻行为的研究进展(英文)

侧沟茧蜂Microplitisspp .是鳞翅目害虫的重要天敌 ,它们在生物防治中的成功应用在很大程度上取决于其成功的搜寻行为。在影响侧沟茧蜂搜寻行为的诸多因素中 ,化学信息物质起着关键作用 ,茧蜂通过感受来自于害虫、植物、害虫 -植物复合体的化学物质而找到害虫。茧蜂还通过学习与经验调整其行为 ,以适应不同的环境 ,提高搜寻的效率。蜂龄、成蜂生理状况、寄主的饲养方法等也对其搜寻行为有影响。本文对上述情况进行了总结 ,并对其在生物防治中的应用进行了讨论。     

应用DELTA系统对几种球束梗孢Gibellula spp.的分类研究

【目的】通过DELTA数据库及其功能扩展,对所采集的球束梗孢标本进行分类鉴定。【方法】利用基于30个表型特征建立的DELTA数据库,通过生成的检索表,自然语言描述,分类单位聚类树及交互式自动鉴定系统进行鉴定。【结果】全部标本鉴定分属为3个种,它们是尾生球束梗孢(粗壮球束梗孢)Gibellula clavulifera var.clavulifera(Petch)SamsonH.C.Evans,密球束梗孢G.leiopus(Vuill.ex Maubl.)Mains和丽球束梗孢G.pulchra Cavara。【结论】基于DELTA系统所建立的的球束梗孢属表型特征数据库及其功能扩展,为该属后续的分类研究和系统发育重建提供了一个有价值的信息平台。