接菌壮秧剂对低磷土壤水稻秧苗生理生化特性的影响

通过苗床培养试验,研究了在低磷土壤上接菌壮秧剂对水稻品种东农423秧苗生理生化特性的影响.结果表明,在低磷土壤上施用接种5406放线菌和溶磷青霉菌P77的壮秧剂可增加植株地上部的含磷量和吸磷量,减少根部的含磷量和吸磷量;提高水稻秧苗的硝酸还原酶活性,增加可溶性糖和可溶性蛋白质的含量,减少硝态氮在植物体内的积累;其Chl a、Chl b、Chl a Chl b和类胡萝卜素含量呈降低趋势,但Chl a/Chl b比值的变化不明显;以上各指标除根部含磷量和Chl a/Chl b外,其它与对照差异均达到极显著水平(P<0.01).研究发现,接菌壮秧剂可以有效改善水稻秧苗的磷素营养状况,且接种P77的效果好于5406,2种菌的接种浓度均以5×107cfu/g效果较佳.     

Polyester-degrading thermophilic actinomycetes isolated from different environment in Taiwan

Thermophilic actinomycetes strains were isolated from various environment in Taiwan and screened for degradation of poly(ethylene succinate) (PES), poly(ε-caprolactone) (PCL) and/or poly(β-hydroxybutyrate) (PHB) by the clear-zone method. Out of 341 strains of thermophilic actinomycetes, 105 isolates were PHB-degraders (30.8%), 198 isolates were PCL-decomposers (58.1%), and 99 isolates could degrade PES (29.0%). Furthermore, 77 isolates could degrade both PHB and PCL (22.6%), 35 isolates could degrade both PHB and PES (10.3%), 81 isolates could degrade both PES and PCL (23.8%) and 31 isolates could degrade the three polyesters used in this study (9.1%). Base on the morphological and chemical characteristics, these 31 isolates belonging to Actinomadura (12.9%), Microbispora (25.8%), Streptomyces (48.4%), Thermoactinomyces (9.7%) and Saccharomonospora genus (3.22%).     

Dynamics of an oligosporous actinomycete population in chernozem soil

Investigation of the dynamics of an oligosporous actinomycete population in chernozem soil in the course of succession induced by soil wetting allowed us to reveal the time intervals and conditions optimal for the isolation of particular oligosporous actinomycetes. Saccharopolysporas and microbisporas proved to be best isolated in the early and late stages of succession, whereas actinomycetes of the subgroupActinomadura and saccharomonosporas could be best isolated in the early and intermediate stages of succession     

云南高原湖泊中高温放线菌四新种

在进行云南高原湖泊水生放线菌研究的过程中,分离到大量高温放线菌,按国内通用的方法进行鉴定,有4个新种。模式菌株Y86—8217,Y86—8100,Y86—8010,Y86—8048均保存于云南省微生物研究所。     

新疆青海中度嗜盐放线菌生物多样性初步研究

从我国新疆、青海等地采集数份盐碱土样或泥样,采用淀粉-酪素琼脂培养基、甘油天门冬酰胺琼脂培养基、土壤浸汁琼脂培养基分别从中分离到8株、32株中度嗜盐放线菌菌株。经形态、生理学特性与全细胞壁氨基酸组分分析结果比较,选取其中的14株进行16S rDNA序列分析。就物种多样性而言,新疆、青海分离到中度嗜盐放线菌分布至少有3个科,5个属。其中有拟诺卡氏菌科（Nocardiopsaceae）的拟诺卡氏菌属(Nocardiopsis)和链单孢菌属（Streptomonospora）;假诺卡氏菌科(Pseudonocardiaceae)的普氏菌属(Prauserella)和糖单孢菌属(Saccharomonospora);链霉菌科(Streptomycetaceae)的链霉菌属(Streptomyces)。就地区分布来讲,新疆分离到的中度嗜盐放线菌种类要远高于青海。     

放线菌Streptomyces sp．FJ3的核糖体工程改良与活性产物的分离

[目的]利用核糖体工程抗性筛选技术,获得有抗菌活性突变株,并对突变株新产生活性物质进行研究.[方法]以三峡库区筛选出的无抗菌活性放线菌野生株为出发菌,通过单菌落挑选与平板划线培养,分离筛选具有链霉素和利福平抗性突变株;通过摇瓶发酵和对发酵液进行纸片法活性测定,获得抗金葡菌活性突变株;采用高效液相色谱法(HPLC)分析其发酵液组分,通过LC-MS对变化峰进行分析;进行16S rDNA及形态学鉴定.[结果]链霉素和利福平对放线菌菌株FJ3的MIC分别为0.5μg/mL和110μg/mL;在FJ3突变菌株中,共获得24株链霉素突变菌株和20株利福平突变菌株,抗菌活性筛选显示6株具有抗菌活性,其中2株链霉素突变菌株对金葡菌有强抑菌活性,采用Doskochilova溶剂系统纸层析结果表明,该活性物质为一种核酸类抗生素,HPLC和LC-MS显示该活性物质可能为硫藤黄菌素.[结论]利用核糖体工程技术可以改变放线菌的次级代谢,获得具有生物活性的突变株,拓展药源放线菌活性菌株新资源.     

Three New Species of Brevibacteria,Brevibacterium antiquum sp. nov., Brevibacterium aurantiacum sp. nov., and Brevibacterium permense sp. nov.

This work deals with the taxonomic study of orange-pigmented bacteria isolated from permafrost sediments, rice plots, and soils contaminated with wastes from the chemical and salt industries that were assigned to the genus Brevibacterium on the basis of phenotypic characteristics, as well as of some strains described previously as Brevibacterium linens. The study revealed three genomic species, whose members and the type strains of the closest species of Brevibacterium had DNA similarity levels between 24 and 59%. The strains of the genomic species differed from each other and from the known species of Brevibacterium in some physiological and biochemical characteristics, as well as in the sugar and polyol composition of their teichoic acids. The 16S rDNA sequence analysis confirmed the assignment of the environmental isolates to the genus Brevibacterium and showed the phylogenetic distinction of the three genomic species. The results obtained in this study allow three new Brevibacterium species to be described: Brevibacterium antiquum (type strain VKM Ac-2118^T = UCM Ac-411^T), Brevibacterium aurantiacum (type strain VKM Ac-2111^T = NCDO 739^T = ATCC 9175^T), and Brevibacterium permense (type strain VKM Ac-2280^T = UCM Ac-413^T).     

Characterization of Bioactive Actinomycetes Isolated from Kadolkele Mangrove Sediments,Sri Lanka

Exploring untapped microbial potentials in previously uncharted environments has become crucial in discovering novel secondary metabolites and enzymes for biotechnological applications. Among prokaryotes, actinomycetes are well recognized for producing a vast range of secondary metabolites and extracellular enzymes. In the present study, we have used surface sediments from ‘Kadolkele’ mangrove ecosystem located in the Negombo lagoon area, Sri Lanka, to isolate actinomycetes with bioactive potentials. A total of six actinomycetes were isolated on modified-starch casein agar and characterized. The isolates were evaluated for their antibacterial activity against four selected bacterial strains and to produce extracellular enzymes: cellulase, amylase, protease, and lipase. Three out of the six isolates exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, and Bacillus cereus, but not against Listeria monocytogenes. Five strains could produce extracellular cellulase, while all six isolates exhibited amylase activity. Only three of the six isolates were positive for protease and lipase assays separately. Ac-1, Ac-2, and Ac-9, identified as Streptomyces spp. with the 16S rRNA gene sequencing, were used for pigment extraction using four different solvents. Acetone-extracted crude pigments of Ac-1and Ac-2 were further used in well-diffusion assays, and growth inhibition of test bacteria was observed only with the crude pigment extract of Ac-2. Further, six different commercially available fabrics were dyed with crude pigments of Ac-1. The dyed fabrics retained the yellow color after acid, alkaline, and cold-water treatments suggesting the potential of the Ac-1 pigment to be used in biotechnological applications.     

四川阿坝不同生境绿绒蒿内生放线菌多样性

【背景】目前国内外对绿绒蒿内生放线菌的研究较为鲜见,利用可培养和免培养的方法可以丰富绿绒蒿内生放线菌资源。【目的】药用植物绿绒蒿生长于高海拔地区,而四川阿坝州生态环境适合绿绒蒿的生长,本研究旨在探究绿绒蒿内生放线菌的多样性及群落结构。【方法】从阿坝州6个不同地理位置采集的药用植物绿绒蒿,经严格的表面消毒后,用可培养和PCR-DGGE技术相结合的方法对其内生放线菌进行分析。【结果】可培养方法分析表明不同器官放线菌数量为根叶茎花;16S r DNA限制性内切酶片段长度多态性(RFLP)分析将供试菌株分为7个遗传群,系统发育分析表明,绿绒蒿内生放线菌可分为3簇遗传群落,链霉菌属(Streptomyces)为优势菌群,占总数的50%,还包括北里孢菌属(Kitasatospora)和厄氏菌属(Oerskovia),其中茎分离的放线菌多样性最好。不同地理位置的绿绒蒿经过PCR-DGGE技术分析表明,采样点松潘尕力台的根、茎、叶多样性指数最好,红原安曲乡的花多样性指数最好,而同一地理位置绿绒蒿内部组织之间总体来看茎和花的多样性指数最好,通过测序条带系统发育发现绿绒蒿内生放线菌可分为8簇遗传群落,红球菌属(Rhodococcus)为优势菌群,占总数的70%,还包括棒杆菌属(Corynebacterium)、诺卡氏菌属(Nocardia)、微球菌属(Micrococcus)、栖霉菌属(Mycetocola)、微杆菌属(Microbacterium)、假诺卡氏菌属(Pseudonocardia)和链霉菌属(Streptomyces)。【结论】绿绒蒿根、茎、叶、花组织中具有丰富的多样性,能够为以后活性物质和药用功效的研究奠定基础。