矿质元素对北虫草继代培养不同菌落子实体产量及菌丝生长速度的影响

主要研究矿质元素对北虫草继代培养中形成的不同类型菌落子实体产量及菌丝生长速度的影响, 旨在探讨矿质元素与子实体产量以及菌丝生长速度的关系。采用正交试验, 将北虫草优良菌株L20在不同矿质元素培养基上进行12次继代培养。结果表明菌株L20在不同培养基中继代培养后形成7种菌落类型, 有子实体形成能力的菌落为Ⅰ、Ⅱ、Ⅲ、Ⅴ型, 其中Ⅰ型菌落产量最高、Ⅲ型中等、Ⅱ型最低, Ⅴ型形成的子实体均为畸形; Ⅳ、Ⅵ、Ⅶ型无子实体形成能力。菌丝生长速度依次为Ⅴ型 > Ⅳ型 > Ⅶ型 > Ⅵ型 > Ⅲ型 > Ⅱ型 >Ⅰ型, 高产型菌落生长速度最慢, 而低产型菌落菌丝徒长, 表明菌落生长速度与子实体产量成负相关。优型菌落——Ⅰ型菌落子实体高产及高产保持代数最多的矿质元素配方为K3Mg2Ca4Mn3Zn2, 其中Mn和K促进子实体高产, K、Mg、Ca有利于高产保持多代。抑制Ⅰ型菌落菌丝徒长的最佳配方为K3Mg2Ca2Mn3Zn2, 其中Mn对其抑制作用最为显著。     

苹果盘二孢的分离培养研究

苹果盘二孢Marssonina coronaria引起的褐斑病是造成我国苹果树早期落叶的主要原因,由于该病菌分离培养困难,阻碍了对其生物学特性的研究,进而影响了对其防治机理和流行规律的研究。本研究应用4种培养基质,探索了3种方法对苹果盘二孢的分离效果。结果表明,3种方法均可分离到病原菌,但组织块分离法和分生孢子团分离法成功率仅有10%左右,而单孢分离法污染少,成功率高达到90%以上,明显优于其他两种方法。不同培养基上菌落形态、大小和产孢情况差异也很大,培养1个月(25℃)后PDA上菌落黑褐色隆起,表面蚯蚓粪状,无气生菌丝,无子实体和基内菌丝;10%V8培养基上菌落中央隆起,黑褐色,表面生少量气生菌丝,边缘放射状,基内菌丝深褐色,有子实体;苹果叶片葡萄糖琼脂培养基(LDA)上菌落平坦,黄褐色,表面生茂密的金黄色气生菌丝,基内菌丝深褐色,有子实体;苹果叶片煎汁葡萄糖琼脂培养基(LEDA)上菌落有明显的不规则隆起,黄褐色至黑褐色,表面生少许气生菌丝,菌落生长缓慢,无基内菌丝,分生孢子盘菌落表面生,菌落直径仅2mm左右,而在其他培养基上的菌落直径可达6-8mm,说明培养基质、分离方法均对苹果盘二孢的分离培养和生长发育有明显的影响。     

褐飞虱共生解脂假丝酵母抗吡虫啉菌株的驯化

为进一步研究共生菌在褐飞虱对吡虫啉产生抗性中的生理生化机制,在稻田杀虫剂对褐飞虱共生解脂假丝酵母生长影响的基础上,选用不同吡虫啉浓度进行抗药性菌株的驯化。结果表明,褐飞虱共生解脂假丝酵母在不同吡虫啉浓度(2 000、1 000和500 mg/L)的固体培养基上继代培养,经过20代后2 000 mg/L培养基上的共生菌菌落数量,与未加吡虫啉的培养基上的菌落数量差异不明显,并且连续3代稳定后定为抗2 000 mg/L吡虫啉的共生菌菌株。在光镜下比较不同抗感吡虫啉菌株假菌丝的形态变化,发现抗吡虫啉菌株的假菌丝出现畸形,而且假丝变短,部分出现了膨大。     

红托竹荪菌种快速分离培养基优化

通过对红托竹荪快速分离培养基优化,提高红托竹荪菌种分离与评价效率。采用响应面分析法,以菌种生长速度为响应值拟合二次多元回归方程,确定培养基配方;测定优化培养基与PDA对照培养基菌丝生长速度和菌丝直径,以菌丝形态、锁状联合和菌落形态等指标评价优化培养基;测定优化培养基与PDA培养基培养菌丝在木屑培养基中菌丝生长速度,验证应用效果。通过试验,筛选出快速分离培养基配方为葡萄糖20.71 g/L、全麦粉8.36 g/L、玉米粉8.07 g/L、琼脂粉18.00 g/L、木屑水1.06 L。快速分离培养基与PDA培养基对比,培养的菌落直径平均增加66.25%,快速分离培养基菌丝日平均生长速度增加33.33%,木屑培养基菌丝日平均生长速度增加44.22%。由于优化培养基中含有淀粉、纤维素等有效成分,其刺激了菌种分泌淀粉酶、纤维素酶等,维持了胞外酶系的完整性。还可根据菌丝培养基过程形成的透明圈大小判定菌种胞外酶产生能力,达到快速评价菌种质量,保障菌种质量的目的。     

苹果盘二孢Marssonina coronaria的分离培养研究

苹果盘二孢Marssonina coronaria引起的褐斑病是造成我国苹果树早期落叶的主要原因,由于该病菌分离培养困难,阻碍了对其生物学特性的研究,进而影响了对其防治机理和流行规律的研究.本研究应用4种培养基质,探索了3种方法对苹果盘二孢的分离效果.结果表明,3种方法均可分离到病原菌,但组织块分离法和分生孢子团分离法成功率仅有10%左右,而单孢分离法污染少,成功率高达到90%以上,明显优于其他两种方法.不同培养基上菌落形态、大小和产孢情况差异也很大,培养1个月(25℃)后PDA上菌落黑褐色隆起,表面蚯蚓粪状,无气生菌丝,无子实体和基内菌丝;10%V8培养基上菌落中央隆起,黑褐色,表面生少量气生菌丝,边缘放射状,基内菌丝深褐色,有子实体;苹果叶片葡萄糖琼脂培养基(LDA)上菌落平坦,黄褐色,表面生茂密的金黄色气生菌丝,基内菌丝深褐色,有子实体;苹果叶片煎汁葡萄糖琼脂培养基(LEDA)上菌落有明显的不规则隆起,黄褐色至黑褐色,表面生少许气生菌丝,菌落生长缓慢,无基内菌丝,分生孢子盘菌落表面生,菌落直径仅2mm左右,而在其他培养基上的菌落直径可达6-8mm,说明培养基质、分离方法均对苹果盘二孢的分离培养和生长发育有明显的影响.     

杏鲍菇最佳培养基的筛选

研究了不同的母种、原种和栽培种培养基对杏鲍菇菌丝生长、子实体产量及生物学效率的影响。结果表明,杏鲍菇在不同配方的培养基上菌丝的生长存在明显差异,其中菌丝生长速度最快、最健壮的母种培养基为PDYA培养基;菌丝生长速度最快、子实体产量最高、生物学效率达91.7%的原种及栽培种培养基为配方2。原种及栽培种培养基的含水率为60%时,菌丝生长快而健壮,在生产上最适宜采用。     

木霉对辣椒疫霉菌抑制作用的超微结构与细胞化学

哈茨木霉菌株NF9和TC3对辣椒疫霉病菌具有强烈的抑制作用。超微结构与细胞化学研究表明,木霉菌丝能够缠绕并寄生疫霉菌菌丝,且重寄生作用主要发生在培养基内的菌丝上。但在绝大多数情况下,木霉菌可直接水解和破坏疫霉菌菌丝,说明木霉抑菌作用的主要机制是直接向外分泌水解酶分解疫霉的细胞壁及细胞质,而不是重寄生作用。不同培养基对木霉的重寄生作用有重要影响,减少培养基中葡萄糖含量可以增强木霉的重寄生作用和抑菌效果。此外,在菌落生长后期,疫霉的新生菌丝均可侵染自身的老菌丝。     

木霉对辣椒疫霉菌抑制作用的超微结构与细胞化*

哈茨木霉菌株NF9和TC3对辣椒疫霉病菌具有强烈的抑制作用。超微结构与细胞化学研究表明,木霉菌丝能够缠绕并寄生疫霉菌菌丝,且重寄生作用主要发生在培养基内的菌丝上。但在绝大多数情况下,木霉菌可直接水解和破坏疫霉菌菌丝,说明木霉抑菌作用的主要机制是直接向外分泌水解酶分解疫霉的细胞壁及细胞质,而不是重寄生作用。不同培养基对木霉的重寄生作用有重要影响,减少培养基中葡萄糖含量可以增强木霉的重寄生作用和抑菌效果。此外,在菌落生长后期,疫霉的新生菌丝均可侵染自身的老菌丝。     

引起石榴枯萎病和甘薯黑斑病的甘薯长喙壳菌菌株生物学特性的比较研究

采用菌丝生长速率法对引起石榴枯萎病和甘薯黑斑病的甘薯长喙壳菌的形态特征,及其在不同培养基、光照、温度、pH值等基本培养条件下菌丝的生长速率等生物学特性的差异进行了比较研究。结果表明,在不同处理培养条件下,石榴枯萎病菌生长速度均快于甘薯黑斑病菌,其菌落形态存在较大差异。二者在甘薯葡萄糖培养基(SPDA)上生长速率最快。在黑暗条件下的生长速率比12h光暗交替、光照处理显著增大。二者最适生长温度皆为25℃,石榴枯萎病菌菌丝生长温度范围为10-36℃,而甘薯黑斑病菌的菌丝生长温度范围为10-33℃。二者菌丝在pH4-12范围内均能生长,最适pH值为6。石榴枯萎病菌菌丝的致死温度为50℃处理10min或52℃处理5min,甘薯黑斑病菌菌丝的致死温度为48℃处理10min或50℃处理5min。二者在完全培养液中产孢量最大,菌丝生长速率随培养基中葡萄糖浓度的减小而增大。     

木霉对辣椒疫霉菌抑制作用的超微结构与细胞化学

哈茨木霉菌株NF9和TC3对辣椒疫霉病菌具有强烈的抑制作用。超微结构与细胞化学研究表明,木霉菌丝能够缠绕并寄生疫霉菌菌丝,且重寄生作用主要发生在培养基内的菌丝上。但在绝大多数情况下,木霉菌可直接水解和破坏疫霉菌菌丝,说明木霉抑菌作用的主要机制是直接向外分泌水解酶分解疫霉的细胞壁及细胞质,而不是重寄生作用。不同培养基对木霉的重寄生作用有重要影响,减少培养基中葡萄糖含量可以增强木霉的重寄生作用和抑菌效果。此外,在菌落生长后期,疫霉的新生菌丝均可侵染自身的老菌丝。     

Development of Candida albicans hyphae in different growth media--variations in growth rates, cell dimensions and timing of morphogenetic events

In six liquid culture media, all of which stimulated Candida albicans to grow in the hyphal form, the rates of hyphal extension and increase in cellular ATP concentration, hyphal diameters, times of evagination of hyphae, times of septum formation and positions of septa in the hyphae appeared to vary independently. There were no discernible associations between properties such as length or volume of hyphal compartments at the time of septation and temporal parameters of hyphal growth. The results suggest that growth environment influences many of the processes contributing to hyphal development, but that these processes are not necessarily interrelated.     

蛹虫草菌丝生长研究

通过对 4种不同来源的蛹虫草菌种 ,在 5种不同配方培养基上菌丝生长情况进行了比较研究。结果表明 ,不同培养基配方对不同来源的蛹虫草菌种培养菌丝的长速和长势存在较大的差异。     

Effect of soil bacteria on hyphal growth of the arbuscular mycorrhizal fungus Glomus claroideum

The effect of 46 bacterial strains isolated from tilled and non-tilled soils collected at 3 localities on the growth of intraradical hyphae of the arbuscular mycorrhizal (AM) fungusGlomus claroideum was demonstrated. A larger number of stimulatory bacterial isolates was obtained from tilled soils, but the bacteria showing the strongest stimulation of hyphal growth were isolated from a soil that had not been cultivated. Isolates obtained from hyphae of AM fungi showed no substantial stimulatory effects, but produced more uniform effects on hyphal growth than the isolates of bacteria obtained from soil. Bacterial cenoses present in 3 different soils differ significantly in their effects on AM fungi.     

Hyphal tip growth in Achlya bisexualis. II. Distribution of cellulose in elongating and non-elongating regions of the wall

Cellulose has been localized in the hyphal wall of elongating and non-elongating hyphae of Achlya bisexualis using a direct enzyme-colloidal-gold method. A number of controls, including several different types of fixation, support the idea that this labeling is specific for cellulose. Both TEM and SEM were used and they gave similar results. The apical area of an elongating hypha lacks cellulose, but the same area of a non-elongating hypha contains cellulose. We have used specific culture media and light microscopic measurements to ensure that we could distinguish between elongating and non-elongating hyphae. The lack of cellulose at the apex of elongating hyphae seems to require a reevaluation of the current concepts of hyphal tip growth in Achlya and related genera. A major question now is to determine whether or not the lack of a microfibrillar component is a universal pattern among all organisms having tip growth.     

Morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of Neurospora crassa.

A comparison was made of the morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of Neurospora crassa. Undifferentiated mycelia were formed during exponential growth on solid media or submerged culture. Hyphae at the margin of differentiated mycelia (colonies) differed from undifferentiated mycelia in diameter, extension rate, extension zone length, and intercalary and apical compartment length. The mean hyphal extension rate (E) of an undifferentiated mycelium was a function of the length of the mycelium's hyphal growth unit (G) and the organism's specific growth rate (alpha). Thus, E=Galpha.     

Macroscopic growth of filamentous fungi on solid substrate explained by a microscopic approach.

A quantitative model predicting biomass growth on solid media has been developed. The model takes into account steric interactions between hyphae and tips at the microscopic level (competition for substrate and tip-hypha collisions). These interactions effect a slowing down of the hyphal, population-averaged extension rate and are responsible, at the microscopic level, for the distribution of tip orientations observed at the colony border. At the macroscopic level, a limiting value of the colony radial extension rate is attained. A mathematical model that combines hyphal branching, tip diffusion, and biomass growth was proposed to explain such behavior. Experiments using Gibberella fujikuroi were performed to validate the model; good agreement between experiments and simulations was achieved. Most parameters can be measured by simple image analysis on the peripheral growth zone, and they have clear physical meaning; that is, they correspond to properties of single, leading hyphae. The model can be used to describe two-dimensional (2D) solid media fermentation experiments under varying culture conditions; the model can also be extended to consider growth in three-dimensional (3D), complex geometry substrates.     

A fungus-specific ras homolog contributes to the hyphal growth and virulence of Aspergillus fumigatus

The Ras family of GTPase proteins has been shown to control morphogenesis in many organisms, including several species of pathogenic fungi. In a previous study, we identified a gene encoding a fungus-specific Ras subfamily homolog, rasB, in Aspergillus fumigatus. Here we report that deletion of A. fumigatus rasB caused decreased germination and growth rates on solid media but had no effect on total biomass accumulation after 24 h of growth in liquid culture. The DeltarasB mutant had an irregular hyphal morphology characterized by increased branching. Expression of rasBDelta113-135, a mutant transgene lacking the conserved rasB internal amino acid insertion, did not complement the deletion phenotype of delayed growth and germination rates and abnormal hyphal morphology. Virulence of the rasB deletion strain was diminished; mice infected with this strain exhibited approximately 65% survival compared to approximately 10% with wild-type and reconstituted strains. These data support the hypothesis that rasB homologs, which are highly conserved among fungi that undergo hyphal growth, control signaling modules important to the directional growth of fungal hyphae.     

Tip growth of <Emphasis Type="Italic">Neurospora crassa</Emphasis> under glucose deprivation

Growth parameters of vegetative hyphae and isolated tip fragments of the mycelial fungus N. crassa were studied after complete substitution of an easily metabolized carbon source (glucose) for a non-metabolized one (sorbitol). The images of growing tips were recorded at 20–30-min intervals. Using original image processing software, geometrical parameters of the hyphal trees (length and number of branches, area of convex polygons circumscribed about the hyphal trees, etc.) were determined and growth characteristics, such as rate of tip elongation (V) and the ratio of the total hyphal length to the number of growing tips (termed “hyphal growth unit”, HGU), were calculated. It is shown that after 4–5-h growth in sorbitol-enriched media growth characteristics of intact hyphae did not differ significantly from the corresponding parameters of hyphae growing in glucose-enriched media. In isolated tip fragments (about 800-μ m long), the values of V were lower than those in intact hyphae but did not depend on the carbon source in the nutrient media. However, in such fragments growing in sorbitol-enriched media the number of branches decreased, while the HGU value and the number of large intracellular vacuoles increased. Staining of cells with a standard chitin probe, Calcofluor White (10 μg/ml), did not reveal any considerable differences in hyphal cell walls and septa in tip fragments grown in the presence of different carbon sources. Possible mechanisms of the dependence of the tip growth parameters on the glucose deficiency are discussed.     

Cyclic AMP control of hierarchical growth pattern of hyphae inNeurospora crassa

Wild-typeNeurospora crassa shows a clear hyphal dominance growth pattern with a hierarchy of hyphal diameters containing wide main hyphae, narrow primary branch hyphae, and still narrower secondary branches. Mutants (cr-1), lacking cyclic AMP, lack this size hierarchy when grown in medium without cyclic AMP. When grown in media containing sufficient cyclic AMP or 8-bromocyclic AMP to correct other morphological aberrations, these mutants still lack hierarchical growth. When grown in the presence of very high levels (3 mM) of 8-bromocyclic AMP, there is a long delayed formation of hyphae of different diameters. It is suggested that differences in cyclic AMP concentrations among the hyphae of wild type may be central to the production of the hierarchical growth pattern.