Relationship between the quality of the inoculum material and carminomycin biosynthesis by a culture of Actinomadura carminata]

The effect of the inoculum mycelium quality on carminomycin biosynthesis by Actinomadura carminata was studied. The time of the organism growth on the culture medium containing cornsteep liquor continued for 6 hours without losing by the inoculum of its seeding qualities during that period. The mycelium growth in the inoculum was more intensive under conditions of moderate aeration, i.e. 0.98-2.64 mg O2H1-min. Anincrease in the aeration rate up to 18.56 mg O2/1-min resulted in the growth suppression up to 40 per cent. No correlation between the aeration rate during the inoculum growth and the culture capacity for carminomycin biosynthesis and of the content of the complex in active components the fermentation medium were observed, when a 5-10 per cent of inoculum was used.     

The Seed-borne Inoculum of Peronospora manshurica, Causal Agent of Soybean Downy Mildew

The seed-borne inoculum of P. manshurica is described using various microscopic techniques and staining reactions. The inoculum, in addition to the oospores, consists of a thin walled mycelium under the hourglass cell layer of the seed coat and a thick walled resting mycelium in the oospore crust on the seed surface. By a modified Feulgen staining technique it was possible to demonstrate that the thin walled and the thick walled resting mycelium as well as thin and thick walled oogonia contain nuclei which are Feulgen positive suggesting that portions of the mycelium of P. manshurica may survive even on the surface of dry, mature seeds.     

Effect of Sclerotinia sclerotiorum on the disease development,growth, oil yield and biochemical changes in plants of Mentha arvensis

Experiment was carried out to determine the effect of Sclerotinia sclerotiorum on the disease development, growth, oil yield and biochemical changes in the plants of Mentha arvensis. With the increase in initial inoculum levels of S. sclerotiorum a corresponding decrease in plant fresh and dry weights were recorded. The maximum reduction in the shoot-roots/suckers fresh weight and shoot-roots/suckers dry weights (39.8%, 43.6%, 40.3% and 42.9%), respectively, was observed at the highest initial inoculum level of 12 g fungal mycelium/5 kg soil as compared to uninoculated control. The infection of roots and suckers due to S. sclerotiorum increased with increasing initial inoculum levels. At the lowest initial inoculum (1.0 g mycelium/5 kg soil), infection was observed 18.0% and at the highest (12 g mycelium/5 kg soil), it was 80.2%. Significant (P ⩽ 0.01) reduction in oil yield, total chlorophyll, total phenol and total sugar content of M. arvensis plants was observed at the lowest inoculum level as compared to uninoculated control.     

Influence of inoculum size on aflatoxin production in home-made yoghurt

In previous works we have studied the influence of different factors on the aflatoxin production in yoghurt. In the present paper we complete our investigations with the study of the influence of the inoculum size. The inoculum sizes used by us were from 4 × 10¹ to 4 × 10⁶. As can be expected, the fungal growth, expressed as dry mycelium weight, was lower in 4 × 10¹ and higher in 4 × 10⁶. The amount of aflatoxin in the mycelium was stable, or increased slightly with the inoculum size. In the substrate, the amount of aflatoxin was stable with little fluctuations, with a higher level of toxin in 4 × 10³ and lower one in 4 × 10⁶. We detected a higher aflatoxin level in the mycelium than in the substrate.     

Antibiotic Production of Hyphal Fractions of Streptomyces griseus: II. Streptomycin Production of Different Fractions Obtained by Density Gradient Centrifugation

The streptomycin-producing activity (SPA) of hyphal fractions from washed mycelium of submerged cultures of Streptomyces griseus strain 52-1, as obtained by density gradient centrifugation, was investigated. Activity of the various fractions differed strongly in intensity. The highest SPA was evident in the unfractionated mycelium. A synergistic effect upon SPA was found in the interaction of cultures of different ages, and a 55% increase in yield was obtained by mixing the 48- and 72-hr cultures. A synergistic effect occurred in all combinations studied. By use of fractions obtained from 72-hr mycelium for inoculation, differences in streptomycin production were noted. Some inoculum fractions yielded a greater amount of streptomycin (36%) than the unfractionated mycelial inoculum.     

Biosorption of Baftkar textile effluent

Decolourization of wastewater from a textile plant by a marine Aspergillus niger was studied. The fungus was previously isolated from Gorgan Bay in the Caspian Sea. The kinetics of decolourization was studied by varying energy sources. The best decolourization was achieved when sucrose was used as source of carbon and energy. NH4+ ion was demonstrated to be the best nitrogen source. Color reduction was found to increase from 80-97% as inoculum concentration increased from 0.04-1.0 g/L. A minimum inoculum of 0.2 g/L is necessary to achieve decolourization. The optimal temperature for the growth of A. niger on Baftkar wastewater is found to be 30 degrees C. 90-96% colour reduction is achieved in 19-20 hr of contact of mycelium cell with the wastewater. Colour reduction in a continuous column reactor of 70% was obtained using treated mycelium (NaOH, 90 degrees C) after 1 hr.     

Microcycle Conidiation and Spore-Carrying Capacity of Colletotrichum gloeosporioides on Solid Media

The effect of spore inoculum density, medium concentration, and temperature on slime-spot formation, spore yield, and mycelium production by Colletotrichum gloeosporioides on agar media were studied with a simple microplate assay. A steady-state spore yield (spore-carrying capacity) independent of inoculum density was reached only on media that supported good fungal growth and sporulation. The spore-carrying capacity was reached earlier, the denser the inoculum. On standard mycological media a high inoculum density (2.5 × 10⁶ spores per ml) resulted in a slimy mass of conidia forming a slime spot, a phenomenon associated with greatly reduced mycelium formation and indicative of microcycle conidiation. In contrast, for a similar inoculum density, enhanced mycelial growth preceded sporulation and overrode slime-spot formation on highly concentrated media; a very low medium concentration resulted in much less mycelium, but spore production was also decreased. Exposure to suboptimal growth temperatures of 36 to 48°C for up to 8 days did not induce microcycle conidiation from inocula that did not form a slime spot at 28°C.     

Foraging patterns of Phallus impudicus, Phanerochaete laevis and Steccherinum fimbriatum between discontinuous resource units in soil

Abstract Wood blocks colonised by the basidiomycetes Phallus impudicus, Phanerochaete laevis and Steccherinum fimbriatum were placed individually in plastic trays containing moist, unsterilised soil. All three fungi grew out radially from the inoculum blocks, forming networks of mycelial cords. Outgrowth patterns of P. impudicus and P. laevis were similar in controls to those in experiments where a second uncolonised wood block was placed as a 'bait' several centimetres away from the inoculum block. However, contact with the bait by S. fimbriatum resulted in marked changes in growth pattern. These changes included cessation of radial extension from the inoculum, thickening of connective mycelium between inoculum and bait, outgrowth from the bait in the original direction of travel and regression of non-connective mycelium. These observations emphasize the collective organisation of mycelial systems and the differences in their growth pattern which can arise from varying foraging strategies.     

Hemagglutinating activity of the fungusLentinus edodes (Berk.) sing [Lentinus edodes (Berk.) Pegler]

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains ofLentinus edodes was studied. The HA activity of the CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures ofL. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied. MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.     

Immobilized Aspergillus sydowii produces xylanase

Summary Spores ofAspergillus sydowii, immobilized in 2.5% caleium alginate was used as inoculum in batch cultures for production of xylanase enzyme using xylan as the sole carbon source. Partially germinated mycelium from these entrapped spores produced significant amount of the enzyme in a short period of 24 hours and the same inoculum could be used repeatedly for at least 5 cycles with less than 10% loss of enzyme activity.     

Degeneration of Streptomyces niveus with Repeated Transfers

Novobiocin production by Streptomyces niveus decreased drastically as the culture was transferred at regular intervals under both sporulating and nonsporulating conditions. Addition of degenerated live mycelium as second inoculum to shake flask fermentations already inoculated with a high-producing strain resulted in sharply depressed novobiocin formation. Fractionated medium of low-producing strain containing either no cells or dead cells had no adverse effect on the antibiotic yield of the high-producing mycelium. It appears that the low-producing mycelium was outgrowing the high-producing mycelium. A study of the growth rates of the two types of mycelium in a clear broth medium indicated no differences in generation time. However, the low-producing strain proved to have a higher efficiency of carbohydrate utilization, thus overgrowing the high-producing strain. It was speculated that culture instability of S. niveus is due to heterocaryosis.     

美味牛肝菌液体深层培养工艺条件的探索

对美味牛肝菌液体深层培养的工艺条件进行探索,得出其最佳摇瓶条件为:温度24～28℃,种龄3天,接种量10%,振荡转速为150r/min,培养时间为5天,在最佳工艺条件下菌丝体干重可达24.8g/L。     

Receptivity of various wheat cultivars to infection by VA-mycorrhizal fungi as influenced by inoculum potential and the relation of VAM-effectiveness to succinic dehydrogenase activity of the mycelium in the roots

Wheat cultivars grown in pots in a greenhouse were inoculated either once or twice with the vesicular-arbuscular mycorrhizal fungus (VAMF) Glomus mosseae. If inoculum was only added to the soil once (before planting) the cultivars showed differences in subsequent VAM development. If additional inoculum was added ten days after planting, VAM development was much increased and cultivars which remained without VAM after only one inoculum application now became mycorrhizal.Succinate dehydrogenase (SDH) activity decreased throughout the experiment, but this decrease was less rapid in mycelium in twice-inoculated plants.No close relationship between SDH-activity and plant growth (VAM effectiveness) was found.     

Hemagglutinating activity of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler]

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains of Lentinus edodes was studied. The HA activity of CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures of L. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied, MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.     

Study of the carbohydrate content in the mycelia of an active strain producing oxytetracycline and in an inactive mutant]

The content of carbohydrates in the mycelium of the active strain and inactive mutant of the oxytetracycline-producing organism under conditions favourable (starch medium) and unfavourable (glucose medium) for the antibiotic biosynthesis was studied. The mycelium of both organisms was fractionated and carbohydrate distribution according to the mycelium fractions and carbohydrate content in every fraction were investigated. No significant differences were observed between the active strain and inactive mutant with respect to the characteristics studied. The carbon source in the medium had the dominating effect on the chemical composition of the mycelium. The mycelium of both strains grown on the starch medium contained much more carbohydrates than that grown on the glucose medium. The carbohydrates of the mycelium grown on the starch medium were mainly found in fraction III and must be represented by polysaccharides.     

Optimization of the Medium and Cultivation Conditions of Penicillium roquefortii f39 Producing the Diketopiperazine Alkaloid Roquefortine

We optimized the medium for cultivation of Penicillium roquefortii f39, a producer of roquefortine. In this medium, the roquefortine yield increased 1.5–2-fold. An increase in roquefortine content was associated with high biomass yield, but not with an increase in biosynthetic activity of the mycelium. Direct correlation was found between extracellular roquefortine concentration and the amount of the inoculum. The use of sucrose in the inoculum medium allowed us to increase the concentration of roquefortine during fermentation to 90 mg/l.     

Characterisation of some Phlebiopsis gigantea isolates with respect to enzymatic activity and decay of Norway spruce wood

The activity of cellulase, peroxidase, phosphatase and dehydrogenase enzymes, together with the content of protocatechuic and vanillic acids, in samples of Norway spruce wood inoculated with 17 different isolates of Phlebiopsis gigantea was measured. The same isolates were used to compare decay activity in samples of Norway spruce wood after incubation for 3 and 6 months. Significant differences in enzyme activity and phenol production were found between aerial mycelium overgrowing the wood sample and the underlying wood. These differences indicated that the nature of the fungal mycelium appears to change depending on whether it is in contact with wood. After 6 months, highly extensive decomposition of the wood was shown by two British isolates. The results confirm a large difference in P. gigantea inoculum among isolates in natural conditions and reinforce the need for constant evaluation of the most active isolates to use in preparations for biocontrol: a problem for both users and registration bodies.     

Influence of inoculum size of Aspergillus parasiticus spores on aflatoxin production.

The influence of the inoculum size on growth and aflatoxin production was examined in Aspergillus parasiticus (NRRL 3145) by using a synthetic medium. The reduction in the number of spores by 4 to 5 log cycles either by serial dilution or by gamma irradiation caused a two fold increase in the toxin production. The decrease in the inoculum size induced a lag in growth of the culture, though the final yield of the mycelium over the 28-day experimental period was the same. The maximal accumulation of aflatoxin was observed on day 14 of incubation. A transition from the biphasic to monophasic pattern in aflatoxin production could be correlated with the size of the inoculum. The enhanced toxin production from dilute inocula was similar to that obtained with the surviving fraction of the spores after gamma irradiation (0 to 150 krads).     

Methodological procedures for detecting antibiotic producers among cultures of the family Micromonosporaceae]

Data on intensification of the search for active cultures among Micromonospora are presented. It was shown that the frequency of detecting the antibiotic-producing cultures among Micromonospora under conditions of fermentation on the corn-glucose medium inoculated with agar blocks amounted to 35 per cent. The use of nutrient media of different composition for growing submerged inoculum of Micromonospora demonstrated that the rate of its growth reached maximum on the peastarch medium. The use of this medium for growing submerged seed material for fermentation in the corn-glucose medium increased the frequency of detecting active cultures from 35 to 43.1 per cent. The assay of Micromonospora antibiotic activity twice, i.e. in 96 and 240 hours of the fermentation process increased the frequency of detecting active cultures up to 57.1 per cent and revealing greater variety of antibiotics. Fermentation of Micromonospora cultures simultaneously on 6 different nutrient media inoculated with submerged seed mycelium and assay of the activity for 2 times, i. e. in 96 and 240 hours allowed a detection of up to 76.2 per cent of active strains out of the total number of the isolates.     

裸脚菇0612-9液体菌种优化及其对后续发酵产活性物质的影响

裸脚菇0612-9次级代谢产物具有强烈抗青绿霉活性,可作为微生物源防腐剂用于柑橘保藏,但是其发酵周期长,产出能耗大效率低。用摇瓶对裸脚菇0612-9的液体菌种培养基、培养条件进行优化并对优化后液体菌种接种种龄、接种量进行探索,最后用5L发酵罐进行放大发酵验证。取样计数测定菌丝球数量、过滤称重测定菌丝干重、HPLC监测活性物质Ⅱ的积累、牛津杯法评价抗青绿霉活性。经研究最佳碳源为玉米粉和麦芽糖,最佳氮源为蛋白胨,最佳液体菌种培养基组成为：玉米粉30g/L、麦芽糖10g/L、蛋白胨15g/L、KH₂PO₄ 2g/L、MgSO₄·7H₂O 1g/L;最佳培养条件：起始pH 5、接种3×Ф7mm菌块、装液量100mL/250mL三角瓶、温度28℃、转速160r/min;优化前菌丝球数46个/10mL,菌丝干重0.28g/100mL,优化后菌球数达985个/10mL,菌丝干重达0.69g/100mL,分别为优化前的21.4倍、2.43倍;后续发酵使用种龄9d的液体菌种、接种量7.5%。优化后液体菌种在发酵罐中后续发酵周期从10d缩短至5d,缩短50%,产量比优化前提高8.28%。