Influence of ectomycorrhizal inoculation on Pinus wallichiana and Cedrus deodara seedlings under nursery conditions

A study was undertaken to examine the extent of root colonization by four locally isolated ectomycorrhizal （ECM） fungi （Hebeloma theobrominum, Boletus dryophilus, Scleroderma citrinum and Suillus luteus） and their effects on seedling growth in Pinus wallichiana and Cedrus deodara under nursery conditions. Seedlings of the two conifers were inoculated with mycelium of ECM fungi and were grown in pots containing sterilized forest soil for six months. The percentage of ECM colonization of roots was 38%-52% in Pinus wallichiana and 33%-48~ in Cedrus deodara. ECM colonization increased shoot height, needle number, shoot and root biomass and survival of inoculated seedlings. Among the four ECM fungi Hebeloma theobrominum was more effective with Pinus wallichiana and Scleroderma citrinum with Cedrus deodara in promoting seedling survival and overall growth. All the four ECM fungi used enhanced growth of inoculated seedlings and thus can be used in afforestation and regeneration programmes in degraded forests ecosystems.     

Vesicular-arbuscular mycorrhiza of Calamagrostis villosa supplied with organic and inorganic phosphorus

Plants of Calamagrostis villosa were cultivated in nutrient solution alone or in association with a vesicular-arbuscular mycorrhizal (VAM) fungus Glomus etunicatum. They were supplied with two levels of inorganic phosphate (Pi; 0.1 or 1 mM) and with or without organic phosphate (dinatriumphenylphosphate, Po; 1 mM). Depression of growth and enhancement of root respiration of mycorrhizal plants in comparison with non-mycorrhizal plants were observed after 12 weeks of cultivation in a growth cabinet. Root colonization was not influenced by the higher phosphorus availability in contrast to the extraradical mycelium (ERM). The lengths of ERM hyphae both attached to the root surface and in the substrate were decreased substantially by higher phosphorus supply, irrespectively of its form. This revised version was published online in July 2006 with corrections to the Cover Date.     

Arbuscular mycorrhiza colonization and development at suboptimal root zone temperature

Temperature has a strong influence on the activity of living organisms. This study, involving two indoor experiments, evaluated the effects of root zone temperature (10, 15 and 23°C) on the formation and development of arbuscular mycorrhizae (AM). In the first trial, greenhouse-grown sorghum [Sorghum bicolor (L.) Moench] was either colonized by Glomus intraradices Schenck & Smith or left non-mycorrhizal. Root length, root and shoot weight and root colonization were measured after 5, 10 and 15 weeks of plant growth. Although suboptimal root zone temperatures reduced growth in both mycorrhizal and non-mycorrhizal plants, mycorrhizal plants were larger than non-mycorrhizal plants after 15 weeks at 15 and 23°C. At suboptimal root zone temperatures, mycorrhizal inoculation sometimes slightly reduced root development. AM colonization was more affected than root growth at suboptimal root zone temperatures. Colonization was markedly reduced at 15°C compared with 23°C, and almost completely inhibited at 10°C. The second experiment was conducted in vitro using transformed carrot (Daucus carota L.) roots supporting G. intraradices. Mycelium length and spore number were measured weekly for 15 weeks. Spore metabolic activity (iodonitrotetrazolium reduction), root length and percentage root colonization were measured after 15 weeks. G. intraradices sporulation was reduced at temperatures below 23°C, while spore metabolic activity was significantly reduced only at 10°C. Root length and in particular percentage colonization were decreased at suboptimal temperatures. A negative interaction between AM hyphal growth and root growth resulting in reduced probability of contact at suboptimal root zone temperatures is proposed to explain the greater reduction observed in root colonization than in root and hyphal growth.     

Comparison of 2-day-old and 14-day-old chicken colonization models for Campylobacter jejuni

In this study, we compared two types of chicken infection models for Campylobacter jejuni in terms of infectious dose required to colonize the chickens and the susceptibility of chickens of different ages to persistent colonization by C. jejuni. In one model, chickens at day 2 posthatching were used, and in the other, 14-day-old chickens were used. The minimum C. jejuni cell number required to colonize 14-day-old chickens was 5 x 10(4) cells, and that for 2-day-old chickens was 5 x 10(3). The ability of various C. jejuni strains to colonize the chicken gastrointestinal tract was the same in both models.     

Assessing in vitro efficacy of certain fungicides to control Sclerotinia sclerotiorum in peanut

The fungal pathogen Sclerotinia sclerotiorum is responsible for Sclerotinia blight in several crops around the world, including peanut. This study was conducted under laboratory conditions to determine the effects of four registered fungicides, Propulse?, Fontelis^®, Omega^® and Endura^® on mycelial growth and pigmentation, as well as sclerotia and oxalic acid production on a growth medium modified with a fungicide and on the pathogenicity of S. sclerotiorum on leaflets detached from Valencia peanut. Propulse, Omega and Fontelis inhibited mycelial growth of S. sclerotiorum, while, mycelial growth on a modified support with Endura was similar to the control treatment. All fungicides, except Endura, inhibited the production of oxalic acid. Pigmentation of the mycelium was observed in both the control and endura treatments. Sclerotia production was observed only in the control treatment. With the exception of Endura, all fungicides were effective in controlling the development of lesions on Valencia peanut leaflets.     

水杨酸、萘乙酸和青霉素对大白桩菇、褐环粘盖牛肝菌及野蘑菇菌丝生长的影响

研究了水杨酸、萘乙酸及青霉素对大白桩菇、褐环粘盖牛肝菌及野蘑菇菌丝生长的影响。结果表明:对大白桩菇,水杨酸的致死浓度不大于1.94×10-4g/mL,培养基中浓度大于1.07×10-4g/mL抑制大白桩菇菌丝生长,浓度在(5.6×10-7)~(5.6×10-5)g/mL范围内能够促进菌丝生长,浓度小于5.6×10-8g/mL则没有明显影响。对褐环粘盖牛肝菌,培养基中水杨酸浓度大于4.76×10-6g/mL有抑制菌丝生长的作用,致死浓度不大于1.90×10-4g/mL。培养基中水杨酸浓度在大于5.6×10-6g/mL条件下对野蘑菇菌丝生长有一定的抑制作用。培养基中萘乙酸浓度在0.056 6~2.264 mg/L范围内对大白桩菇菌丝生长有一定的促进作用。培养基中萘乙酸浓度在0.95~4.75、0.056 6~1.132 mg/L范围内分别对褐环粘盖牛肝菌、野蘑菇菌丝生长基本无影响。培养基中青霉素浓度在(4.57×10-7)~(4.57×10-3)g/mL范围内对褐环粘盖牛肝菌菌丝生长具有抑制作用。培养基中青霉素浓度较低时对大白桩菇菌丝生长起促进作用,浓度大于1.88×10-3g/mL时对大白桩菇菌丝生长起抑制作用。而培养基中青霉素浓度在(1.88×10-7)~(1.88×10-3)g/mL范围内对野蘑菇菌丝生长无明显作用。     

Fungal mycelium--the source of chitosan for chromatography

Mycelium of the mold Aspergillus niger was used as a raw material for the preparation of microbial chitosan. Aspergillus niger, the mold used for the production of citric acid, contains approx. 15% of chitin, which can be separated, transformed into chitosan, and used as a sorbent for chromatography. The main advantage of this material in comparison with krill chitosan is the uniformity of particle size leading to the low back-pressure in the column. The other advantage is the fact, that original fibrous structure of mycelial pellets could be stabilized before chitosan preparation by cross-linking with glutaraldehyde. The product prepared by this way -- crosslinked chitosan of uniform particle size, is highly porous, with high water regain and, as a result, low sedimentation velocity. Low sedimentation velocity is not disadvantage in chromatographic application, but may form some problems in batchwise operation. Chitosan as a polymer of glucosamine is anion exchanger in nature and the chromatographic properties of this anion exchanger was demonstrated by the chromatography of bovine blood plasma, glucose oxidase, and chicken pepsinogen. In all cases, the course of chromatography on crosslinked chitosan was compared with the chromatography on MONO Q (bovine blood plasma) or DEAE-cellulose (glucose oxidase, chicken pepsinogen) under the same protocol.     

丽珠肠乐（回春生）活菌的定植性研究

无菌小鼠试验证明：丽珠肠乐（回春生）活菌可以在体内定植，接种后从１６小时至８天活杀小鼠。活菌定植数量相对地稳定，盲肠内容物为１０７－１０９ＣＦＵ／ｇ，其参于膜茵群的构成，膜菌群（空肠、回肠和盲肠）的数量为１０５－１０８ＣＦＵ／ｇ。     

布氏白僵菌菌丝制剂的贮存活力

本试验制备了布氏白僵菌（Beauveriabrongniartii）9405的几种菌丝颗粒剂和粉剂,并测定其贮存活力。当贮存6个月时,在4℃和室温贮存的藻胶颗粒剂的存活率比贮存1个月时分别下降了31．4％～76．8％和76．0％～92．6％。4个粉剂中,7号和10号在4℃的存活率比贮存1个月分别下降11.0％和8．5％,而其它两个的存活率却略有增加;在室温贮存的存活率下降8．2％～33．1％。颗粒剂在土壤中有一个恢复生长过程,然后逐渐衰落。     

8个平菇栽培菌株的亲缘关系及培养特性研究

研究了8个平菇栽培菌株的亲缘关系及培养特性。结果表明:8个栽培菌株分别属于3个品种,根据子实体性状可划分为深色和浅色2个品系。其中菌株P8、P5和P1菌丝生长速度快,生长势强,产量高。     

肠道菌群对耐碳青霉烯类肠杆菌科细菌定殖抗性的研究进展

耐碳青霉烯类肠杆菌科细菌(carbapenem-resistant Enterobacteriaceae,CRE)在肠腔中定殖通常先于或并存于CRE的感染。正常情况下,定殖的CRE、肠道菌群和宿主相互作用,处于稳定平衡的状态,当肠道菌群出现失调时,肠道正常菌群失去对定殖CRE的抵抗力,增加CRE感染的风险。大量研究表明通过肠道共生菌群对CRE的定殖抗性不仅可以预防感染,而且也可以降低医疗环境中患者间相互传播的风险。本文就CRE的流行现状、肠杆菌科细菌定殖机制以及肠道共生菌群对CRE定殖抗性机制作一综述,以期为CRE感染的防控工作提供新思路和新方法。     

Effects of attachment substrate,larval diet,and temperature on development and survival of immature Coquillettidia linealis (Skuse) and Coquillettidia xanthogaster (Edwards)

A sustainable colony allowed investigations into attachment substrates, diet and temperature in the development of the immature stages of Cq. linealis and its local congener Cq. xanthogaster. As immatures, these mosquitoes attach to submerged plants for respiration, and various field‐collected and laboratory‐raised plants were compared with non‐living substrates. Hydroponically‐grown wheat plant seedlings provided the most suitable attachment substrate. Development and survival of immatures to eclosion were investigated with three types and three quantities of a standardized diet. Development and survival at rearing temperatures between 10° and 30° C were also investigated. Diet type appeared to have little influence on development. However, at the lowest diet quantity, development to pupation was significantly reduced while the highest diet quantity impacted on the eclosion of pupae. Mean duration of immature development for Cq. linealis increased as temperature decreased. Time from 1^st instar to median eclosion did not differ significantly between 23° C (6.0 weeks) and 25° C (5.3 weeks), although it was 10 weeks at 20° C, and 30° C was lethal. For Cq. xanthogaster, similarly, mean duration of immature development increased as temperature decreased, with development time from 1^st instar to median eclosion significantly longer at 20° C (7.5 weeks) compared to 23° C (5.0 weeks) and 30° C (4.0 weeks).     

立枯丝核菌营养菌丝多型性观察

采用了2种不同的方法对立枯丝核菌营养菌丝的形态进行了观察和比较,观察到2种不同的营养菌丝的形态,即菌核类和假分生孢子类。为以后进一步研究立枯丝核菌营养菌丝的多型性奠定了一定的基础。     

樟芝菌丝体的氨基酸成分分析

测定了樟芝发酵菌丝体中游离氨基酸和结合氨基酸的含量。结果表明,樟芝菌丝体中含有丰富的8种人体必需氨基酸、支链氨基酸和谷氨酸,其中8种必需氨基酸含量是FAO(联合国粮农组织)标准的5.55倍,而芳香族氨基酸的含量却很低。在测定过程中,由于采用了酸水解,菌丝体中的色氨酸被破坏,而其余17种氨基酸均被测出,含量极其丰富。尤其是支链氨基酸的含量远大于α-酪蛋白、卵蛋白和大豆球蛋白。     

氨基寡糖素对黄瓜白粉病菌侵染的抑制作用*

用透射电子显微镜,研究了寡聚糖类药剂中科6号(2%氨基寡糖素)处理黄瓜Cucumis sativus 植株叶片后对白粉病菌Sphaerotheca fuliginea侵染的抑制作用。超微结构观察表明,病菌发育受到明显抑制,表现为白粉菌菌丝细胞质凝聚,细胞器解体和细胞组织崩解;吸器内的原生质电子致密度加深,吸器畸形,吸器壁增厚,细胞器解体,最终吸器坏死。     

Differentiation and wall chemistry of Agaricus bisporus vegetative and aggregated micelia

Changes in the chemical composition of isolated cell walls and fractions were encountered during the differentiation of vegetative and aggregated mycelia of Agaricus bisporus.Differentiation was accompanied by quantitative variations of the wall polysaccharidic components. Neutral carbohydrates were composed of glucose, galactose, mannose and xylose and glucosamine as the only amino sugar. Differences in wall chemistry were correlated to the secondary and tertiary mycelial forms.     

粗柄鸡菌菌丝体培养和无性繁殖过程研究初报

鸡菌属菌物是一类具有商业前景的食物蕈菌。对Ｔｅｒｍｉｔｏｍｙｃｅｓａｌｂｕｍｉｎｏｓｕｓ（Ｂｅｒｋ）Ｈｅｉｍ进行了广泛研究,其它种类的研究仅见于Ｔ．ｆｕｌｇｉｎｏｓｕｓ（Ｂｅｒｋ．）Ｈｅｉｍ。笔者首次对Ｔ．ｒｏｂｕｓｔｕｓ（Ｂｅｅｌｉ）Ｈｅｉｍ粗柄鸡菌进行了纯培养研究,其菌丝体生长所需的碳源以麦芽糖为佳,葡萄糖、蔗糖次之;氮源以蛋白胨、酵母粉较好;天然材料的热水提取物,如松针、蚁巢圃、马铃薯、平菇出菇废料、蚕豆的混合物能促进菌丝生长;培养基在ｐＨ４．５左右最佳,可用０．０５％的柠檬酸调节。菌丝体纯培养很容易形成大量分生孢子和小白球菌,表明小白球菌是粗柄鸡菌菌丝体无性繁殖过程的一个阶段。