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41.
扁座壳孢(Aschersonia placenta Berk.et Br.)是黑胶粉虱病原真菌,在寄主初龄幼虫期使用孢子悬浮液喷雾,个体容易感病,而且致死力较强。该菌最适生长温度24—26℃,暴发性流行季节气候条件多阴雨,相对湿度在85%以上。病原能在一般培养基上生长繁殖。在自然界以感病致死虫尸为营养载体,粘附在叶面,不断形成分生孢子,产生再次侵染,对控制害虫虫口增长作用显著,是综合防治中不可忽视的生物因素。 相似文献
42.
A number of water-borne fungi with branched conidia have been shown to be basidiomycetes. These fungi resemble aquatic hyphomyectes in their habitat, conidial morphology and ontogeny. Their conidia are typically tetraradiate or elaborately branched. Ingoldiella hamata and Taeniospora gracilis, which produce clamped, tetraradiate conidia, are anamorphs connected to the teleomorphs Sistotrema hamalum and Leptosporomyces galzinii, respectively. Both teleomorphs are members of the Corticiaceae. Dendrosporomyces prolifer and D. splendens, which produce non-clamped conidia resembling the aquatic hyphomycete Dendrospora, have binucleate conidia and typical dolipore septa are present. Other water-borne fungi with basidiomycete affinities include Ingoldiella fibulata and Tricladiomyces malaysianum. 相似文献
43.
An acidic α-D-mannosidase has been isolated from the culture filtrate of a wood-rotting Basidiomycete, Pycnoporus sanguineus and the molecular and enzymatic properties of the enzyme determined. The extracellular mannosidase was homogeneous on PAGE at pH 9.4. The Mr as determined by SDS-polyacrylamide disc gel electrophoresis was 64000, and the pI was pH 4.7 using electrofocusing. The purified enzyme had a pH optimum of 4.5 with Baker's yeast mannan and had no activity towards p-nitrophenyl-α-mannoside. The Km and kcat values for Manα1-2Man at pH 4.5 and 30° were 0.9 mM and 1.9 sec. the enzyme had no activity towards Manα1-3Manα1-2Man, and it cleaved specifically the 1,2-α-linked side chain of yeast α-mannan, producing free α-D-mannose. 相似文献
44.
A radioimmunoassay technique for indole-3-acetic acid is described. The method has successfully been used to measure extractable indole-3-acetic acid in fungal and plant materials and is able to detect as little as 0.3 pmol. As non-radioactive antigen the methyl ester of indole-3-acetic acid is used and the radioactive antigen is tritiated. An acid-catalyzed esterification of indole-3-acetic acid is used for conversion into methyl ester. The measuring range of the assay is 0.3–10 pmol. In the assay, separation of free and bound fractions is achieved by dextran-coated charcoal, leaving the bound fraction in the supernatant. 相似文献
45.
Summary The distribution of nematophagous fungi in soil collected from a deciduous woodland is compared to various biotic and abiotic soil factors. The microfungi are isolated at all depths down to a maximum of 35 cm. Predators forming constricting rings, adhesive branches and adhesive knobs are restricted to the upper litter and humus layers. The net forming predators and endoparasites are isolated at all depths, although they are significantly more abundant in the lower mineral rich soils. A much greater species diversity of nematophagous fungi is recorded in the upper organic zones.Preliminary soil analysis indicates thatCephalosporium balanoides is independent of all soil variables, while predators able to form traps spontaneously are restricted to the organic soils which are rich in nematodes. Non-spontaneous trap forming predators, which are excellent saprophytes, are isolated from the deeper soils which are low in nutrients. The ecological significance of these results is discussed. 相似文献
46.
Pythium pythioides (Roze & Cornu) Ramsbottom is recorded from Algeria. Since its original discovery in 1869 this species had not been found back. A brief history is given and morphological and reproductive characters are discussed. 相似文献
47.
An oxygen-evolving complex has been highly purified from the thermophilic cyanobacterium Synechococcus sp. The complex, which reproducibly showed 5 major polypeptide bands of 47, 40, 35, 30 and 9 kDa on SDS-polyacrylamide gel electrophoresis and contained 3.2 Mn per QA, had an oxygen-evolving activity of 300–400 μmol/mg chl per h in the presence of 5 mM MnCl2; or CaCl2. The complex most likely represents a minimum functional unit of the photosynthetic oxygen evolution. 相似文献
48.
Methanobacterium thermoaggregans is a new thermophilic autotrophic rod-shaped methane producing bacterium. The organism likes to form aggregates during growth and utilizes only H2 and CO2 as substrates. Growth optimum is at 65°C with a doubling time of 3.5 h. Optimal growth occurs at pH-values between 7 and 7.5. The addition of yeast extract to the mineral salt medium stimulates growth. The DNA base composition is 42 mol% G+C. The organism was isolated from mud taken from a cattle pasture. Because of its optimal growth temperature and its tendency to form aggregates the nameMethanobacterium thermoaggregans is suggested.Abbreviations G+C
Guanine+cytosine 相似文献
49.
50.
Thermophilic anaerobic spirochetes in New Zealand hot springs 总被引:1,自引:0,他引:1
Abstract Electron and light microscopy revealed the presence of spirochetes in New Zealand thermal springs. The spirochete population in one spring studied (Kuirau Lake) was affected by fluctuations in temperature and/or pool level. A pure culture of the strictly anaerobic bacterium revealed that it grew optimally at a temperature of 45–50°C, with no growth occurring above 60°C, and a pH of 7.0–7.5 with no growth occurring at pH 5.5 or 8.5. Growth was inhibited by chloramphenicol, penicillin, streptomycin, tetracycline and neomycin but not by d -cycloserine, novobiocin or phosphomycin at 10 μg/ml. A wide range of carbohydrates were utilized but not organic acids. Acetate was the major end product of glucose fermentation with substantial amounts of ethanol and traces of lactate being produced. 相似文献