真菌孢子烷烃生物标志物特征及其热演化试验的初步研究   总被引：1，自引：1，他引：1  

张惠之  王开发 《地球化学》1997,26(3):37-44

以一种类似地层中无孔多胞孢的现代真菌链格孢属孢子为样品，研究真菌孢子的原生烃烷烃馏分生物标志物及其热解生烃特征。实验结果表明，真菌孢子样品原生烃类的烷烃馏分，主要由正烷烃、异构烷烃和链烯烃相成。正烷烃约占抽提物总量的０．１８％、ｎＣ１９，烷占正烷烃总量的２４．１％。  相似文献   

Oxidative Ce3+ sequestration by fungal manganese oxides with an associated Mn(II) oxidase activity     

《Applied Geochemistry》2016

Sequestration of Ce³⁺ by biogenic manganese oxides (BMOs) formed by a Mn(II)-oxidizing fungus, Acremonium strictum strain KR21-2, was examined at pH 6.0. In anaerobic Ce³⁺ solution, newly formed BMOs exhibited stoichiometric Ce³⁺ oxidation, where the molar ratio of Ce³⁺ sequestered (Ce_seq) relative to Mn²⁺ released (Mn_rel) was maintained at approximately two throughout the reaction. A similar Ce³⁺ sequestration trend was observed in anaerobic treatment of BMOs in which the associated Mn(II) oxidase was completely inactivated by heating at 85 °C for 1 h or by adding 50 mM NaN₃. Aerobic Ce³⁺ treatment of newly formed BMO (enzymatically active) resulted in excessive Ce³⁺ sequestration over Mn²⁺ release, yielding Ce_seq/Mn_rel > 200, whereas heated or poisoned BMOs released a significant amount of Mn²⁺ with lower Ce³⁺ sequestration efficiency. Consequently, self-regeneration by the Mn(II) oxidase in newly formed BMO effectively suppressed Mn²⁺ release and enhanced oxidative Ce³⁺ sequestration under aerobic conditions. Repeated treatments of heated or poisoned BMOs under aerobic conditions confirmed that oxidative Ce³⁺ sequestration continued even after most Mn oxide was released from the solid phase, indicating auto-catalytic Ce³⁺ oxidation at the solid phase produced through primary Ce³⁺ oxidation by BMO. From X-ray diffraction analysis, the resultant solid phases formed through Ce³⁺ oxidation by BMO under both aerobic and anaerobic conditions consisted of cerianite with crystal sizes of 5.00–7.23 Å. Such nano-sized CeO₂ (CeO_2,BMO) showed faster auto-catalytic Ce³⁺ oxidation than that on well-crystalized cerianite under aerobic conditions, where the normalized pseudo-first order rate constants for auto-catalytic Ce³⁺ oxidation on CeO_2,BMO was two orders of magnitude higher. Consequently, we concluded that Ce³⁺ contact with BMOs sequesters Ce³⁺ through two oxidation paths: primary Ce³⁺ oxidation by BMOs produces nano-sized crystalline cerianite, and subsequent auto-catalytic Ce³⁺ oxidation efficiently occurs using dissolved oxygen as the oxidizing agent. Pretreatment of newly formed BMOs with La³⁺ solution resulted in decreased rate constants for primary Ce³⁺ oxidation by BMO due to site blocking by La³⁺ sorption. The results presented herein increase our understanding of the role of BMO in oxidative Ce³⁺ sequestration process(es) through enzymatic and abiotic paths in natural environments and provide supporting evidence for the potential application of BMOs towards the recovery of Ce³⁺ from contaminated waters.  相似文献   

产低温淀粉酶的海洋真菌筛选及研究   总被引：18，自引：1，他引：18  

张刚  汪天虹  张臻峰  汪浩  肖天 《海洋科学》2002,26(2):3-5

从黄、东海的近海海底泥样中分离到6株产淀粉酶活力较高的丝状真菌，对其中产淀粉酶活力最高的Penicillum sp.FS 010441号菌体产酶条件及酶学性质进行了初步研究。该菌最适生长温度为15℃，最高生长温度为40℃，在0℃也可生长，是典型的耐冷菌。对Penicillum sp.FS 010441进行固体培养每克干曲酶活达2622U.Penicillum sp.FS 010441所产低温淀粉酶最适作用pH值为6.0，最适反应温度为40℃，但在0℃也表现出一定酶活，而在15℃有较强的酶活。该低温淀粉酶在洗涤、食品、饲料、制药和酿酒等行业可望有广泛的应用前景。  相似文献   

Phenolics and Proteins Affecting Palatability of Spartina Leaves to the Gastropod Littoraria irrorata     

Felix  Bärlocher Steven Y.  Newell 《Marine Ecology》1994,15(1):65-75

Along the southeastern coast of the United States, the saltmarsh periwinkle Littoraria irrorata is a major consumer of Spartina alterniflora . It prefers to feed on dead rather than living plants. During senescence and early decay, S. alterniflora leaves become colonized by fungi, their phenolic content declines, and their lipid content increases. In this study, the food preferences of L. irrorata were assessed by offering intact leaves or leaf powder suspended in agar. Relative palatabilities were determined by measuring the weight loss of intact leaves, or by estimating the area of feeding marks left on the surface of leaf powder suspensions. Both techniques demonstrated a clear preference for standing dead rather than yellow-green (senescent) leaves. Yellow-green leaves contained methanol-soluble feeding deterrents. A comparable deterrent effect could be achieved by adding ferulic acid, a phenolic compound common in yellow-green S. alterniflora , to leaf powder. The deterrent effects of methanol extracts or ferulic acid could be neutralized by simultaneously adding fungal mycelium or BSA. Littoraria irrorata preferred leaves colonized by fungi or bacteria over sterile leaves. When offered a choice of sterile leaves colonized by different fungi, the results were variable. In one experiment, L. irrorata clearly preferred one of three leaffungus combinations. The same preference was shown after the food items were treated with methanol/chloroform to remove lipids. In a second experiment with four other fungal strains, there was only a clear preference for one leaf-fungus combination after removal of lipids. The results suggest that the saltmarsh periwinkle prefers S. alterniflora leaves with low concentrations of phenolic deterrents, most likely ferulic acid, and with sufficient fungal biomass. The food choice may be influenced to a smaller degree by fungal components, which, depending on the species or strain, may be lipids or other compounds.  相似文献   

海洋真菌及其活性物质的研究概况   总被引：5，自引：0，他引：5  

王琳  骆祝华  黄翔玲  裴耀文  叶德赞 《台湾海峡》2002,21(3):367-371

海洋微生物种类繁多，是筛选新药的丰富资源宝库。陆地真菌是仅次于放线菌的多产抗生素的微生物类群，而海洋真菌正在成为海洋药源微生物研究的新热点。海洋真菌产生的生物活性物质已经引起研究者的关注，并将成为海洋药物的重要来源。本文结合国内外文献报道，阐述了海洋真菌及其活性物质的研究情况。  相似文献   

塔里木河下游丛枝菌根植物的侵染     

孟晓燕  尹林克  陈理 《干旱区地理》2008,31(1):102-108

通过对塔里木河下游自然和人工植物群落中的15种主要建群种植物根系菌根的定殖状况的调查及对菌根侵染部位、菌根中的泡囊、丛枝和菌丝的观察,其结果显示:其中11种植物可被AM真菌侵染,占所调查植物种总数的73.33%,野生乡土植物表现出较高的菌根侵染率和侵染强度,其中有84.62%的植物为菌根植物,且乔木、多年生草本和灌木类植物全部为菌根植物,一年生草本植物未见AM真菌侵染;人工引入种蓼科的泡果沙拐枣(Calligonum junceum)和藜科的梭梭柴(Haloxylon ammodendron)均未见有AM真菌侵染。丛枝菌根真菌侵染率、侵染强度与植物所属的科属关系较密切,也与真菌群落所处时空环境及土壤深度有关。  相似文献   

An investigation on tolerance and accumulation of a facultative marine fungus <Emphasis Type="Italic">Aspergillus flavus</Emphasis> to pentavalent arsenic     

Anjana K. Vala  Vipul Davariya  R. V. Upadhyay 《中国海洋大学学报(英文版)》2010,9(1):65-67

Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested. Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L⁻¹ and 50 mg L⁻¹, indicating its tolerance to the metal. Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L⁻¹ than at 25 mg L⁻¹. The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation. Arsenic contents (mg g⁻¹) in the fungus when exposed to 50 mg L⁻¹ As (V) were measured as 11.1773, 4.0983, and 8.0000 mg g⁻¹ on day 3, 6 and 9, respectively. The highest content was observed initially, i.e. on day 3, followed by a decline and a rise again. These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.  相似文献   

厦门西港西南部潮间带光滩土壤微生物的数量变化   总被引：10，自引：0，他引：10  

张瑜斌  王文卿  庄铁诚  林鹏 《台湾海峡》2000,19(1):54-59

研究了厦门西港西南部潮间带无植被滩涂土壤三大类群微生物的数量,结果表明光滩土壤中平均总菌数为18．4×104个/g(dry),细菌、放线菌和丝状真菌平均数量分别为17．4×103、10.1×103和2．1×101个/g(dry),分别占总菌数的94．53％、5.45％和0．02％;不同位点的总菌数及细菌、放线菌、丝状真菌的数量与它们所占总菌数的百分比存在着差异,这与不同位点的土壤有机质含量、N含量和受污染干扰的程度相关,数量特征可作为环境监测的生物学指标之一;放线菌和丝状真菌的数量与土壤盐含量有关,放线菌在低盐份下的培养数量多、生长好,高盐份胁迫可能是丝状真菌数量少的原因之一。  相似文献   

Microbially Contaminated Water in Urban Fountains as a Hidden Source of Infections     

Barbara D. Modrzewska  Magdalena Bartnicka  Joanna Blaszkowska 《洁净——土壤、空气、水》2019,47(8)

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Freshwater lichens and habitat zonation of mountain streams     

《Limnologica》2017

Freshwater lichens of selected Carpathian streams were investigated to identify their diversity and distribution patterns. Lichens were investigated along six transects, each running across three different habitats (hydrological zones: submerged, splash and riparian), established in upper, middle and lower reaches of the streams and the data were a subject to statistical analyses. The studied mountain streams provided suitable habitats for a number of aquatic and semi-aquatic lichens and species richness in both streams was very similar. Overall, 52 species of lichens were identified from all sampling plots (γ diversity). Species number for a single plot (α diversity) ranged from 1 to 14 species and differences in species composition between the plots (β diversity) were high. Differences were mainly noted for typical terrestrial lichens occurring in riparian zones. The location along the stream reaches did not have a significant effect on species diversity and distribution. The hydrological zone appeared to be the most important predictor explaining the small-scale occurrence and diversity of lichens with species assembled into distinct, low-diversity communities in the transition from submerged to riparian habitats. The distinction among hydrological zones and their lichen biota were corroborated by nMDS analyses. The method of defined plots provides a way of recording baseline data for a particular river, which can be repeated (monitor) in the future.  相似文献