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1.
G. E. Walker 《Plant and Soil》1984,78(3):431-432
Summary
Aphelenchus avenae and various unidentified bacteria and actinomycetes were cultured from soil samples taken from a pine-forest and a wheat-field.
The nematode failed to reproduce in significant numbers on cultures of these micro-organisms and was apparently unable to
utilize them as food sources. 相似文献
2.
A comparative study was conducted on the effect of NH4Cl on growth, vesicle formation and formation of nitrogenase of Frankia strains Cc1.17 and Cp1.2, derived from root nodules of Colletia cruciata and Comptonia peregrina, respectively. On a medium without combined nitrogen (P-N), both strains formed spherical cells, called vesicles, like many other Frankia strains. Data are presented on the number of vesicles per mg protein, after cultivation in media with sodium propionate as C-source without combined nitrogen (P-N) or with 0.2 g NH4Cl/l (P+N). Strain Cp1.2 as may other Frankia strains, showed on P+N medium a very strong reduction of vesicle formation of 99% relative to the number of vesicles formed on P-N medium, after 11 days growth. However, in strain Cc11.17 this reduction was only 70%. The occurence of relatively large numbers of vesicles in P+N media has not yet been reported for other Frankia strains. No acetylene reduction activity was found in NH
4
+
-grown cells. The regulation of induction of nitrogenase in Frankia by NH4Cl was tested by immuno-gelectrophoresis using antisera against nitrogenase of Rhizobium leguminosarum PRE. The component I of the enzyme showed crossreactivity while the component II had only a weak crossreaction. The experiments indicated that no nitrogenase was detectable in the NH
4
+
-grown cells. For the localization of nitrogenase, relative amounts of the enzyme were compared in whole cells and vesicle-enriched fractions. Western blots showed a significant enrichment of nitrogenase in the vesicle fractions, which indicated that most of the nitrogenase was localized in the vesicle. 相似文献
3.
Summary
Hippophaë rhamnoides seedlings were grown in sterilized and unsterilized soil from a decliningH. rhamnoides scrub, to which different numbers ofLongidorus sp. andTylenchorhynchus microphasmis were added. In sterilized and unsterilized soil, retardation of growth, content of dry matter in the shoots, and incidence of deformed short lateral roots of test plants were positively correlated with counts of both nematode species. Nitrogen content in the shoots, nodulation on the roots of test plants and increase increase in nematodes were negatively correlated with the initial number of both nematode species in sterilized soil. In unsterilized soil, an unknown biotic factor was present that reduces growth ofH. rhamnoides, nodulation and multiplication of the nematodes. This factor seems to interact with the nematodes in reducing growth ofH. rhamnoides.Deceased. 相似文献
4.
István Papp László Dorgai Péter Papp Erzsébet Jónás Ferenc Olasz László Orosz 《Molecular & general genetics : MGG》1993,240(2):258-264
Bacteriophage 16-3 inserts its genome into the chromosome of Rhizobium meliloti strain 41 (Rm41) by site-specific recombination. The DNA regions around the bacterial attachment site (attB) and one of the hybrid attachment sites bordering the integrated prophage (attL) were cloned and their nucleotide sequences determined. We demonstrated that the 51 by region, where the phage and bacterial DNA sequences are identical, is active as a target site for phage integration. Furthermore it overlaps the 3 end of a putative proline tRNA gene. This gene shows 79% similartiy to the corresponding proline tRNA-like genomic target sequence of certain integrative plasmids in Actinomycetes. 相似文献
5.
Summary This study examined the effects of trifluralin (,,-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), a soil incorporated herbicide, on soil microflora both in the general soil environment and in the rhizosphere of trifluralin damaged wheat roots. Two Dark Brown Chernozemic soils were treated with various trifluralin rates in the growth chamber and wheat [Triticum aestivum L. Neepawa] was seeded. Trifluralin generally had no effect on fungi, bacteria, or actinomycete populations in either the general soil or in the rhizosphere. CO2 evolution was unchanged when trifluralin was added to the soil. In wheat plots, at two field locations, there were no significant effects of trifluralin (1.0 kg ha–1) on soil fungi, bacteria, actinomycete, denitrifying bacteria, and nitrifying Nitrobacter propulations. A pure culture study with 42 soil microorganisms showed that many isolates were inhibited at 400 to 100,000 g g–1 but not at concentrations <16 g g–1. Similar data were obtained from tests on four different soils. These studies indicate that trifluralin is unlikely to cause changes in the numbers of soil microorganisms when used at recommended levels. 相似文献
6.
Abstract A method using membrane filters of appropriate pore size, to selectively isolate actinomycetes from a mixed population of soil microorganisms, is described.
The method is based on the ability of actinomycetes to propagate and pass through the pores of filters while bacteria and fungi are retained on the membrane surface. 相似文献
The method is based on the ability of actinomycetes to propagate and pass through the pores of filters while bacteria and fungi are retained on the membrane surface. 相似文献
7.
《Bioorganic & medicinal chemistry letters》2020,30(7):127005
Two new macrolide metabolites of the hygrolidin family, catenulisporidins A and B (1 and 2), together with a known compound hygrolidin (3), were isolated from the culture broth of the rare actinobacterium Catenulispora sp. KCB13F192. Their structures were elucidated on the basis of HRESIMS spectrometric and NMR spectroscopic analyses. Catenulisporidins A and B are the first example of natural hygrolidin and bafilomycin derivatives featuring a modified macrolide ring, and catenulisporidin A possesses a tetrahydrofuran ring through an ether linkage between C-7 and C-10. In cell-based fluorescent imaging and immunoblot assays, the three compounds were shown to inhibit autophagic flux in HeLa cells. 相似文献
8.
M. Alisch A. Feuerhack H. Müller B. Mensak J. Andreaus 《Biocatalysis and Biotransformation》2013,31(5-6):347-351
The modification of polyethylene terephthalate (PET) fibres by extracellular enzymes produced by actinomycetes was investigated. Cultivation of isolates in media containing PET yarn and suberin, a plant polyester composed of aliphatic and aromatic moieties, induced the production of p-nitrophenyl butyrate hydrolyzing enzymes. Incubation of enzyme preparations from the isolates M5, M9 and Thermomonospora fusca KW3b with PET yarn resulted in an increase in the absorbance of the reaction mixtures at 240 nm indicating the release of terephthalic acid or its esters catalyzed by the enzymes. The results of dyeing of enzyme-treated PET fabrics with a reactive dye (CI Reactive Red 2) indicated an increase in hydroxyl groups at the fibre surfaces as a result of the enzyme treatment. 相似文献
9.
Min Tseng Ming‐Jen Cheng Ta‐Wei Liu Ih‐Sheng Chen Ming‐Der Wu Hsun‐Shuo Chang Gwo‐Fang Yuan 《化学与生物多样性》2013,10(2):303-312
An investigation on the secondary metabolites from the BuOH extract of the fermentation broth of the thermotolerant polyester‐degrading actinomycete Actinomadura miaoliensis BCRC 16873 was carried out. One previously undescribed α‐pyrone (=pyran‐2‐one) derivative, designated as miaolienone ( 1 ), and a new butanolide, miaolinolide ( 2 ), together with 13 known compounds, 3 – 15 , were obtained. Their structures were established on the basis of extensive 1D‐ and 2D‐NMR analyses in combination with HR‐MS experiments. In addition, the isolated compounds 1 – 15 were evaluated for the inhibitory effects of the isolates on the production of tumor necrosis factor (TNF‐α) induced by lipopolysaccharide (LPS). Among the isolates, 1 and 2 significantly inhibited TNF‐α production in U937 cells in vitro, and the IC50 values were 0.59 and 0.76 μM , respectively. Compounds 3 – 5 displayed moderate inhibitory activities on LPS‐induced TNF‐α production. 相似文献
10.
通过对大肠埃希菌和枯草芽胞杆菌抗菌活性初步筛选,从北部湾近海珊瑚礁区5个沉积物样品中成功分离得到51株具有不同抗菌活性的放线菌,其中9株具有较强抗菌能力。根据这9株放线菌的菌落和孢子形态,可确定它们都属于链霉菌属。 RAPD-PCR分析表明这9株放线菌为6种不同类型,16S rDNA序列和系统发生树分析表明,9株放线菌可划分到4个大的类群6种不同类型,且结果显示RAPD-PCR聚类分析与16S rDNA序列聚类分析的结果具有较大的一致性。生理生化鉴定结果表明,分离株与亲缘关系最近的放线菌模式菌株的生理生化特征均存在差异,这说明分离株为放线菌新种的可能性比较大。这6种放线菌具有较为广谱的抑菌活性,并且抑菌活性均存在一定的差异,说明其可能分泌出多种结构功能不同的活性次生代谢产物。研究结果表明,广西北部湾近海珊瑚礁区系沉积物蕴藏着丰富的可供药物开发的放线菌资源。 相似文献