Arthrographis kalrae soluble antigens present hemolytic and cytotoxic activities

Arthrographis kalrae is a dimorphic, cosmopolitan and neurotropic fungus that has been described as a rare human pathogen. This study investigated the hemolytic and cytotoxic activities of A. kalrae cell-free antigens (CFAs). Total CFAs and their Sephadex chromatography fractions were tested on mouse erythrocytes for hemolysis and on the P3U1 cell line for cytotoxicity. Hemolytic and cytotoxic activities were detected in distinct molecular mass (MM) fractions. Additionally, antibodies against isogenic erythrocytes sensitized with CFAs (anti-E-CFAs) inhibited hemolysis but not cytotoxicity. Hemolysis was not affected by heating, and a higher reactivity was detected in the carbohydrate-rich fractions, which decreased after reduction by periodate treatment. The pioneering nature of this work is due to the demonstration of the cytotoxic activity in A. kalrae and the suggestion that this activity may be due to molecules distinct from the hemolytic factor, with the latter potentially being a component with a high MM.     

Interactions between arbuscular mycorrhizal fungi and fungivorous nematodes on the growth and arsenic uptake of tobacco in arsenic-contaminated soils

The effects of inoculation with two AM fungi (M1, Glomus caledonium; M2, Glomus spp. and Acaulospora spp.) and a fungivorous nematode Aphelenchoides sp. on growth and arsenic (As) uptake of Nicotiana tabacum L. were investigated in soils contaminated with a range of As. The reproduction of Aphelenchoides sp. was triggered by the co-inoculation of AM fungi regardless of AM fungal isolates and As levels. Stimulative effects of Aphelenchoides sp. on the development of mycorrhiza, slightly different between two AM fungi, were found particularly at the lowest As level. Irrespective of mycorrhizal inoculi, increasing soil As level decreased plant growth, but increased plant As uptake. Co-inoculation of AM fungi and Aphelenchoides sp. led plants to achieving further growth and greater As accumulation at the lowest As level. Results showed that the interactions between AM fungi and fungivorous nematodes were important in plant As tolerance and phytoextraction at low level As-polluted soil.     

绿肥影响农田土传病害的研究进展

土传病害是制约我国农业可持续发展的因素之一。绿肥作为高效清洁的有机肥源,与主作物合理搭配,可有效降低主作物土传病害的发生和危害,是减少化学药剂使用的重要措施。因此,综述绿肥对土传病害的防控效果与机制,对于绿肥推广应用和土传病害绿色防控具有重要意义。绿肥影响作物土传病害的研究主要集中于土传真菌病害和线虫病害,且大多数研究表明,绿肥可通过增强主作物整体抗病水平,对病原菌的化感抑制作用和改善土壤理化性质,增加土壤微生物中拮抗菌多样性和丰富度等,显著降低主作物土传病害发病率和严重程度。然而,绿肥影响主作物病害的作用机制研究不够深入,绿肥-主作物搭配模式和绿肥调控主作物病害的社会经济学效益仍需探究。同时,加强绿肥-主作物病害一体化防控及绿肥与根际促生菌、生防菌等其他有机改良剂或与适当的化学防控措施之间协同作用的研究,是未来需要加强的研究方向。     

广州地区番石榴病害鉴定

根据近几年对广州地区番石榴病害调查,初步鉴定出番石榴病害13种;真菌病害12种,藻类病害1种。其中果实病害7种,叶斑类6种。果实上以炭疽病严重,其次为褐腐病。黑腐病(Botryodiplodia theobromae Pat.);褐腐病(phomopsis psidii de Camara);茎点霉果腐病(phoma psidii Ahmad);果褐点病(Cercospora psidii Rengel);褐污斑病(Mycovellosiella myrtacearum A.N.Rai et al );叶斑病(phyllosticta psidii.Tassi);叶枯病(phomopsis destructum D.P.C. Rao,Agrawal et Saksena);灰斑病(pestalotiopsis disseminatum (Thuem.)Stey.)8种病害系国内首次报道。3种病原为新种,将另文发表。本文最后讨论了有待于进一步研究的问题。     

玉米秸秆降解真菌的筛选鉴定

为筛选适宜的玉米秸秆纤维素降解菌株作为玉米秸秆腐熟菌剂菌株资源储备,通过采用腐殖玉米秸秆土壤微生物培养筛选、刚果红水解圈测试及酶活测定等多种方法的应用,筛选得到2株具有纤维降解能力的真菌1#菌株和2#菌株。经形态学和分子生物学鉴定,初步确定1#菌株为长枝木霉,2#菌株为聚多曲霉。真菌1#菌株和2#菌株在刚果红培养基上均呈现比生长圈大2倍的水解圈。2个菌株在液体、固体2种酶液发酵情况下均表现内切酶活较强（65.202～217.614 U/mL）,均高于外切酶活（55.398～85.322 U/mL）和滤纸酶活（46.074～141.366U/mL）,认为这2个菌株可作为玉米秸秆专用腐熟菌剂研发的储备菌株。     

真菌侵染对泡桐材微观结构及主要组分的影响

进行了变色真菌对泡桐木材微观构造及主要组分的影响研究,作了链格孢菌（Alternaria alternata)侵染泡桐木材试验,检测了真菌对泡桐木材的侵染状况,并确定了真菌侵蚀泡桐木材的主要部位,测试了泡桐木材在真菌作用下的成分变化,阐明了真菌导致泡桐木材发生变色的物理化学过程。     

长期施肥对南方典型水稻土养分含量及真菌群落的影响

利用江西省农业科学院31年的长期肥料定位试验,选取不施肥(对照)、单施化肥、70%化肥配施30%有机肥、50%化肥配施50%有机肥和30%化肥配施70%有机肥等5个处理,通过常规分析和454-高通量测序技术,研究了长期不同施肥条件下,我国南方典型水稻土养分含量和真菌群落结构的变化。结果表明,在酸性水稻土上,长期单施化肥显著降低土壤p H值,但随着有机肥配施比例的提高p H明显上升;有机和无机肥配施显著提高土壤有机质、有效氮磷含量以及微生物碳氮量。单施化肥土壤真菌18S r DNA序列数比配施有机肥的多1倍,但真菌种(属)数减少了11~40种;前20种优势真菌的丰富度占真菌总量的78.82%~91.51%,以子囊菌最多(7?13种),所占比例最大(23.13%?75.09%);与对照相比,配施有机肥的土壤中有14?15种优势真菌与之相同,而单施化肥的土壤中仅有10种一致;主成分分析结果表明单施化肥处理的真菌群落组成与其他各处理存在显著差异。因此,单施化肥造成土壤酸化加剧,真菌数量成倍增加,但种类显著减少,其丰富度和多样性明显降低,并改变优势真菌种群,相应提高了土壤病原真菌过度繁殖的风险。而有机和无机肥配施有利于维持水稻土壤健康生态环境和真菌种群多样性。     

霉变玉米分离真菌YMF-7产物中毒素成分的识别

[目的]研究霉变玉米分离的真菌YMF-7代谢产物中的毒性成分。[方法]利用海虾毒性指标,采用Sephadex LH-20、硅胶和HPLC等柱色谱技术对YMF-7毒性菌株发酵物进行毒性追踪分离。[结果]共分离得到2个化合物,结构鉴定为化合物1为Gliotoxin(6),化合物2为Gliocladin(7)。经海虾毒性测定,结果表明,化合物1对海虾的LC50值为0.34μg/ml,化合物2对海虾的LC50值为2.10μg/ml。[结论]该2种化合物为YMF-7发酵物中的主要毒性成分。     

桑枝食用菌对1-脱氧野尻霉素的富集作用

[目的]探讨食用菌对桑枝中1-脱氧野尻霉素（1-deoxynojimycin,DNJ）的富集作用。[方法]利用反相高效液相色谱法,研究耳菇、香菇、金针菇、鸡腿菇、银耳、姬菇、黑木耳、灵芝、猴头菇9种食用菌对桑枝中1-脱氧野尻霉素（1-deoxyno jimycin,DNJ）的富集能力。[结果]供试食用菌种均不能自我合成DNJ,但黑木耳、灵芝和猴头菇对DNJ有富集作用,而且其菌盖的富集能力远远高于菌柄。随着培养料中桑枝屑比例的增加,灵芝和猴头菇菌盖中DNJ含量也随之增加,在50%桑枝屑时达到最大,分别为0.0704%和0.0472%,再增加桑枝屑比例,则其菌盖中DNJ含量下降,当桑枝屑比例为80%时,其菌盖中DNJ含量分别降为0.0474%和0.0327%。[结论]该研究可为开发具有降血糖功效的桑枝食用菌提供理论依据和参考。     

覆盖对果园土壤真菌数量年变化的影响

试验结果表明，在整个果树生长期内，覆盖可明显增加各土层中真菌的数量，０ ～２０ｃｍ 土层中，年平均真菌数量增加７９ ．３９％ ，２０ ～４０ｃｍ 土层中增加２８ ．２４ ％ ，４０ ～６０ｃｍ 土层中增加８５ ．０５ ％ 。无论覆盖与对照，不同土层真菌数量年变化均呈单峰曲线变化，高峰出现在８ 月份。