Mycelial Production Research Articles

Effects of slash retention and wood ash addition on fine root biomass and production and fungal mycelium in a Norway spruce stand in SW Sweden

In the study reported here we examined the short-term effects (1–3 years) of slash retention (SR) and the long-term effects (13–15 years) of wood-ash application (A) on fine roots and mycorrhizae in a 40-year-old Norway spruce forest in southwest Sweden. Soil cores were used to obtain estimates of the biomass (g m −2) of roots in three diameter classes (<0.5, 0.5–1 and 1–2 mm), root length density (RLD), specific root length (SRL) and mycorrhizal root tip density (RTD). Fine root (<1 mm) length production and mortality, and mycelium production, were estimated using minirhizotron and mesh bag techniques, respectively. Compared with the control plots (C), the biomass of fine roots in diameter classes <0.5 mm and 0.5–1 mm was significantly higher in A plots, but lower in SR plots. In addition, RLD was significantly lower in the humus layer of SR plots than in the humus layers of C and A plots, but not in the other layers. None of the treatments affected the SRL. In all soil layers, the SR treatment resulted in significant reductions in the number of ectomycorrhizal root tips, and the mycelia production of fungi in mesh bags, relative to the C treatment, but the C and A treatments induced no significant changes in these variables. Fine root length production in the C, A and SR plots amounted to 94, 87 and 70 mm tube −1 during the 2003 growing season, respectively. Fine root mortality in treated plots did not change over the course of the study. We suggest that leaving logging residues on fertile sites may result in nitrogen mineralisation, which may in turn induce reductions in root biomass, and both root and mycelium production, and consequently affect nutrient uptake and the accumulation of organic carbon in soil derived from roots and mycorrhizae.

The first linkage map of the plant-pathogenic basidiomyceteTyphula ishikariensis

Speckled snow mold, caused by the basidiomycete Typhula ishikariensis Imai, is one of the most prominent winter diseases on perennial grasses and cereal crops in the northern hemisphere. The first linkage map of T. ishikariensis was constructed using a population of 93 sibling monokaryons derived from a single dikaryotic hybrid isolate that was created by a hyphal fusion of two monokaryotic parental isolates. The parental isolates were produced from a pathogenic dikaryotic isolate collected from a golf course in Wisconsin. The two parents exhibit significant differences in the production of aerial mycelium and sclerotia, and in their aggressiveness on creeping bentgrass (Agrostis stolonifera L.). A total of 251 loci were mapped, comprising 89 inter-simple sequence repeat (ISSR) and 160 random amplified polymorphic DNA (RAPD) markers along with 2 phenotype-based mating-type (MAT) loci. The MAT loci were mapped on linkage groups (LGs) 1 and 7. The markers were evenly distributed over 7 LGs, covering 436 cM with an average marker interval of 2.2 cM. Seven chromosomes were cytologically observed using germ tube bursting methods with acetocarmine staining. This reference linkage map of T. ishikariensis should provide a framework for the mapping of quantitatively controlled traits such as fungal growth, survival, and virulence/avirulence under low temperatures. The map should also be utilized for studying the genome organization of the cold-loving plant-pathogenic Typhula spp. and for comparative genome analysis among fungal taxa.

Glucose and ammonium additions affect needle decomposition and carbon allocation by the litter degrading fungus Mycena epipterygia

Saprotrophic microorganisms in soils have traditionally been assumed to be carbon (C) limited, since additions of readily assimilable carbohydrates usually result in increased respiration. In many forest soils, however, rapid nitrogen (N) immobilization and increased microbial growth in response to N addition indicate N limitation. Here we test whether this apparent contradiction could be explained by changes in C allocation between microbial growth and respiration (i.e. changed C-use efficiency) under controlled conditions in laboratory microcosms. Respiration, mycelial production and needle mass loss were monitored after application of glucose or ammonium sulphate to Pinus sylvestris needles inoculated with the litter decomposer fungus Mycena epipterygia. Addition of ammonium resulted in a 32% increase in respiration, 31% increase in needle mass loss and increased mycelial production, indicating that both growth and activity of the fungus were N limited. In spite of N limitation, additions of glucose resulted in a 19% increase in respiration but had no effect on mycelial production and led to a 17% decrease in needle mass loss, indicating a reduced C-use efficiency of the fungus. The capacity of individual fungi to adapt their C-use efficiency to C availability implies that additions of labile C could increase respiration even under N-limited conditions.

Formação de ectomicorrizas por monocários e dicários de Pisolithus sp. e interações nutricionais em Eucalyptus grandis

A germinação de basidiósporos de Pisolithus spp. dá origem a monocários, caracterizados por possuírem um único núcleo haplóide por célula. No campo, o eucalipto associa-se a micélios dicarióticos de Pisolithus spp., não havendo relatos sobre a capacidade dos monocários em estabelecer a associação ectomicorrízica com a planta hospedeira nessas condições. Embora os monocários de Pisolithus sp. sejam capazes de formar a associação ectomicorrízica in vitro, nada se sabe sobre a capacidade dessas estirpes em promover a absorção de nutrientes e o crescimento do eucalipto. O objetivo deste trabalho foi estudar a formação de ectomicorrizas por isolados monocarióticos e dicarióticos de Pisolithus sp. em Eucalyptus grandis, sob condições de casa de vegetação, bem como investigar as relações entre o estabelecimento da associação e o crescimento e a absorção de P, Ca, Mg, K, Cu e Zn pelas plantas. Caracterizou-se, também, a produção de massa seca micelial e a absorção de nutrientes pelos isolados fúngicos in vitro. Os isolados monocarióticos e dicarióticos testados variaram na produção de massa seca micelial e na capacidade de absorção de nutrientes. Em geral, os monocários apresentaram maiores índices de eficiência de utilização de nutrientes do que os dicários. Todos os isolados monocarióticos e dicarióticos formaram ectomicorrizas típicas quando associados com E. grandis. A presença dos isolados fúngicos monocarióticos associados às raízes laterais resultou em aumento do diâmetro radial das células da epiderme radicular, característico das ectomicorrizas de eucalipto, indicando que os monocários, à semelhança dos dicários, são capazes de produzir reguladores de crescimento. As médias de percentagem de colonização das raízes pelos isolados monocarióticos e dicarióticos variaram de 12 a 76 %. A absorção de Ca, Mg e K foi estimulada de forma expressiva pela presença das ectomicorrizas, com aumentos de até 760 vezes, demonstrando a relevância dessa associação no suprimento desses macronutrientes, especialmente o Ca. Alguns isolados monocarióticos são tão eficientes quanto os dicários na colonização radicular e na absorção de nutrientes. A caracterização dos monocários de Pisolithus sp. é necessária para se estabelecer a seleção e o cruzamento dos isolados com características desejáveis, visando ao melhoramento genético e à maior eficiência da associação simbiótica. Este trabalho constitui o primeiro relato das interações nutricionais entre monocários de Pisolithus sp. e a planta hospedeira.

Polar vineyard pruning extracts increase the activity of the main ligninolytic enzymes in Lentinula edodes cultures

Lentinula edodes is considered an alternative recycling agent for agricultural wastes, and there have been several studies to understand the relationship between its growth and ligninolytic activity. We tested the effect of wood from viticulture pruning, extracted with solvents of differing polarity, on the biomass production and activity pattern of ligninolytic enzymes. The analysis was done by measuring the mycelial dry mass and enzyme activity of liquid growth medium during the culture of L. edodes, adding either single extracts or a combination of extracts. Polar extracts enhanced mycelial production, and the activity patterns of lignin peroxidase, manganese peroxidase, aryl alcohol oxidase, and laccase were comparable to their activities predicted by ligninolysis models proposed for other fungi. We conclude that the polar extracts could be useful for enhancing fungal biomass production and for modifying lignin degradation because the regulation of ligninolytic enzyme activity is differentially influenced by the polarity of the extract.

Study of mycelial growth and bioactive polysaccharide production in batch and fed-batch culture of Grifola frondosa

The fermentation of Grifola frondosa was investigated in the shake flasks and a 5-L jar fermenter in batch and fed-batch modes. In the shake-flask experiments, the preferable mycelial growth and exopolysaccharide (EPS) production was observed at relatively low pH; maltose and glucose were preferred carbon sources for high mycelial production. The EPS was doubled after 13 d of cultivation when glucose was increased from 2% to 4%. Yeast extract (YE) (0.4%) in combination with corn steep powder (CSP) (0.6%) and YE (0.8%) in combination with CSP (1.2%) were preferred nitrogen sources for high mycelial production and EPS production, respectively. All plant oils tested significantly stimulate cell growth of G. frondosa but they failed to enhance EPS production. The EPS products usually consisted of two fractions of different molecular sizes varied by the plant oils used. The fed-batch fermentation by glucose feeding was performed when the glucose concentration in the medium was lower than 0.5% (5 g/L), which greatly enhanced the accumulation of mycelial biomass and EPS; the mycelial biomass and EPS were 3.97 g/L and 1.04 g/L before glucose feeding, which reached 8.23 g/L and 3.88 g/L at 13 d of cultivation. In contrast, the mycelial biomass and EPS in the batch fermentation were 6.7 g/L and 3.3 g/L at 13 d of cultivation.

The effects of culture media, solid substrates, and relative humidity on growth, sporulation and conidial discharge of Valdensinia heterodoxa

Valdensinia heterodoxa ( Sclerotiniacae) is a potential fungal bioherbicide for control of salal ( Gaultheria shallon). The effect of culture media, substrates and relative humidity (RH) on growth, sporulation and conidial discharge of V. heterodoxa was determined for two isolates PFC2761 and PFC3027 in vitro. Culture media significantly affected the growth, sporulation, and conidial discharge of V. heterodoxa. Of eight agar media used, colony radial growth was optimal on salal oatmeal agar and salal potato dextrose agar for isolates PFC2761 and PFC3027, respectively; whereas sporulation was at an optimum on salal oatmeal agar for both isolates. Of the eight liquid media tested, mycelial production was highest on wheat bran–salal–potato dextrose broth. Growth on solid substrates greatly stimulated sporulation and conidial discharge of V. heterodoxa. Of the 12 solid substrates used, the greatest numbers of discharged conidia were observed from wheat bran and wheat bran–salal within 14 d of sporulation. Sporulation on solid substrates continued for 42 d. RH significantly affected the sporulation and conidial discharge for both isolates across all solid substrates tested. No conidia were produced or discharged below 93 % RH on wheat bran–salal and millet. With an increase of the RH from 93 to 97 %, sporulation and the number of discharged conidia increased significantly for both isolates on wheat bran–salal, but not on millet.

Innovative Effect of Illite on Improved Microbiological Conversion of L-Tyrosine to 3,4 Dihydroxy Phenyl L-Alanine (L-DOPA) by Aspergillus oryzae ME2 Under Acidic Reaction Conditions

In the present investigation, the previous ultraviolet irradiated mutant strain of Aspergillus oryzae UV-7 was further improved in terms of 3,4 dihydroxy phenyl L-alanine (L-DOPA) activity after chemical mutagenesis through 1-methyl 3-nitro 1-nitroso guanidine (MNNG = 250-1500 microg/ml) treatment (0-30 min). Among several mutant variants, the one that produced a larger amount of L-DOPA from L-tyrosine was designated to as ME2 and it was made 2-deoxy-D-glucose-resistant by growing it at various concentrations of 2 dg (0.01-0.025 %, w/v) in Vogel's agar medium. Relatively better production of L-DOPA (> 0.60 mg/ml) was obtained when 2.0% (w/v) glucose was used as a carbon source in the mycelium production medium and the tyrosinase activity increased constitutively (1.08 mg/ml), which resulted in a greater production of L-DOPA. At optimum pH0 (pH 6.0) and reaction time (60 min), more than 65% sugar was utilized for cell mass formation. The maximum conversion of L-tyrosine to L-DOPA (0.428 mg/ml) was achieved 60 min after the biochemical reaction. Mould mycelium was used for microbiological conversion of L-tyrosine to L-DOPA because tyrosinases, beta-carboxylases, and tyrosine hydroxylases are intracellular enzymes. The effect of illite (1.0 x 10(6)-6.0 x 10(6) M) on biochemical conversion of L-tyrosine to L-DOPA by Aspergillus oryzae ME(2 )was also carried out. Best results of L-DOPA biosynthesis were observed when the concentration of illite was 3.5 x 10(-6) M (1.686 mg/ml L-DOPA produced with 1.525 mg/ml consumption of L-tyrosine). It was noted that the addition of illite not only increased enzyme activity but also enhanced the permeability of cell membrane to facilitate the secretion of enzymes into the reaction broth. The comparison of kinetic parameters showed the ability of mutant to yield L-DOPA (i.e., Yp/x 7.360 +/- 0.04 mg/mg). When the culture grown on various illite concentrations was monitored for Qp, Qs, and qp, there was significant enhancement (p < 0.025) in these variables over the control, which indicate that the study can be commercially applicable on stirred and magnetic rotary drums. Overall, there was up to 3-fold (Qp = 0.290 mg/L-DOPA produced/ml/h) enhancement in the product formation rate, which is highly encouraging (HS, LSD 0.456).

Increased ectomycorrhizal fungal abundance after long‐term fertilization and warming of two arctic tundra ecosystems

Shrub abundance is expected to increase with enhanced temperature and nutrient availability in the Arctic, and associated changes in abundance of ectomycorrhizal (EM) fungi could be a key link between plant responses and longer-term changes in soil organic matter storage. This study quantifies the response in EM fungal abundance to long-term warming and fertilization in two arctic ecosystems with contrasting responses of the EM shrub Betula nana. Ergosterol was used as a biomarker for living fungal biomass in roots and organic soil and ingrowth bags were used to estimate EM mycelial production. We measured 15N and 13C natural abundance to identify the EM-saprotrophic divide in fungal sporocarps and to validate the EM origin of mycelia in the ingrowth bags. Fungal biomass in soil and EM mycelial production increased with fertilization at both tundra sites, and with warming at one site. This was caused partly by increased dominance of EM plants and partly by stimulation of EM mycelial growth. We conclude that cycling of carbon and nitrogen through EM fungi will increase when strongly nutrient-limited arctic ecosystems are exposed to a warmer and more nutrient-rich environment. This has potential consequences for below-ground litter quality and quantity, and for accumulation of organic matter in arctic soils.

Improved production by fed-batch cultivation and some properties of Cu/Zn-superoxide dismutase from the fungal strain Humicola lutea 103

Cu/Zn-containing superoxide dismutase (Cu/Zn-SOD) from the fungal strain Humicola lutea 103 is a naturally glycosylated antioxidant enzyme which has been demonstrated to have a protective effect against myeloid Graffi tumor in hamsters and experimental influenza virus infection in mice. In this work, an improvement of enzyme production was achieved by using both an improved growing strategy and a more efficient purification protocol. The optimized fed-batch cultivation, with 7.5 mg/ml glucose fed daily after 24 h, resulted in prolonged growth and abundant mycelium production, as well as in improvement in enzyme production. A 2-fold increase in the total SOD activity and a significant increase in enzyme production were achieved (from 1.5- to 3.2-fold). Fed-batch technology contributed to a 24 h stabilization period of biosynthesis in which every stop of fermentation can be acceptable, thus making this fermentation a process of industrial interest. In addition, the improved purification procedure offers a reduction of purification steps and enhanced enzyme yield (1.6-fold). The molecular mass was proven to be 15,940 Da for the subunit and the conformational dynamics of the protein in solution was studied by electrospray ionization mass spectrometry (ESI-MS).

Mycosphaerella fijiensis, Causal Agent of Black Sigatoka of Musa spp. Found in Puerto Rico and Identified by Polymerase Chain Reaction.

Black Sigatoka, also known as black leaf streak, is caused by Mycosphaerella fijiensis Morelet (anamorph Pseudocercospora fijiensis (Morelet) Deighton). It is the most significant disease of bananas and plantains (Musa spp.) because most of the economically important cultivars of exported and staple commodities are highly susceptible. The Caribbean is one of the few regions of the world where black Sigatoka is not widespread. Black Sigatoka has been reported in the Bahamas, Cuba, Hispaniola, and Jamaica (2). Yellow Sigatoka, caused by M. musicola Leach (anamorph P. musae (Zimm.) Deighton), has been recognized in Puerto Rico since 1938-1939 (3). In August 2004, symptoms resembling black Sigatoka were first observed in Añasco, Puerto Rico by extension personnel from the University of Puerto Rico. Since black and yellow Sigatoka produce similar disease symptoms, a survey was conducted in the western banana- and plantain-production region of Puerto Rico to confirm the presence of black Sigatoka. Leaf samples were collected from production fields near the towns of Las Marias, Maricao, and Añasco. Single-ascospore isolates were recovered using the discharge technique from moistened pseudothecia in necrotic lesions that were inverted over water agar, and ascospores were transferred to potato dextrose agar. The isolates were subcultured in potato dextrose broth for mycelium production. DNA was isolated from mycelium with the FastDNA kit (Q-Biogen, Irvine, CA) for 19 isolates. Internal transcribed spacer as well as the 5.8s rDNA regions were polymerase chain reaction amplified with primers specific to M. fijiensis or M. musicola (1). Amplification products (˜1,100 bp) were observed for 18 of the 19 isolates, 6 of which were M. fijiensis and the remaining 12 were M. musicola, while the positive controls for both species were also amplified with the respective primer pairs. M. fijiensis was recovered from production fields close to all three towns. The source of M. fijiensis in Puerto Rico is unclear, but it may have originated from introduced leaf material and/or wind dispersed ascospores from neighboring countries. The presence of black Sigatoka in Puerto Rico will most likely increase production costs where fungicide applications will be needed to maintain yields. The USDA-ARS, Tropical Agriculture Research Station is the official Musa spp. germplasm repository for the National Plant Germplasm System. As such, efforts are underway to introduce and evaluate black Sigatoka disease-resistant clones that can satisfy local and export market criteria.

Effectiveness of calcium salts, hydrogen peroxide, azoxystrobin, and antagonistic bacteria to control post-harvest rot on tobacco caused by Rhizopus oryzae

Rhizopus rot, caused by the fungus Rhizopus oryzae (Mucorales, Zygomycota) is the most economically important post-harvest disease of flue-cured tobacco and is also known to cause diseases on vegetables and fruits. In case of high infection rates, losses in can reach up to 100% during curing of tobacco leaves. The primary sites of entry of this pathogen are wounds on leaves which are inflicted during harvest and handling. Several compounds were first tested in vitro to determine their antifungal capacities, then applied to racks filled with freshly harvested leaves to prevent colonization by R. oryzae during the subsequent curing process. Calcium propionate, hydrogen peroxide, and azoxystrobin reduced mycelial growth, spore production, and germination of R. oryzae in in vitro tests, whereas calcium chloride mainly influenced the production of fungal biomass. As calcium propionate was phytotoxic when applied to leaves, only calcium chloride, hydrogen peroxide, and azoxystrobin were selected for rack treatments. In addition, fluorescent pseudomonads were tested against natural infections of leaves by the fungus. Hydrogen peroxide had no effect on post-harvest decay. However, disease severity in flue-cured tobacco was significantly reduced by calcium chloride and fluorescent pseudomonads used alone or in combination, and nearly repressed by azoxystrobin. Therefore, an application of antagonistic bacteria alone or in combination with calcium chloride is a valuable alternative in pest management of flue-cured tobacco where residual fungicides have to be avoided.

The Biosynthesis of Kasugamycin, an Antibiotic against Rice Blast Disease, with Particular Reference to the Involvement of rpoZ, a Gene Encoding RNA Polymerase Omega Subunit

Biosynthetic genes of kasugamycin (KSM), an aminoglycoside antibiotic produced by Streptomyces kasugaensis, forms a cluster within the chromosome. A cloned 22.4-kb cluster region contains almost all the enzyme-coding genes required for KSM biosynthesis together with kac338, a gene for KSM acetyltransferase, and kasKLM, a set of genes encoding an ABC transporter, both of which participate in KSM self-resistance as well as kasT encoding a KSM-synthesis-specific transcriptional activator of the biosynthetic genes. Furthermore, rpoZ, encoding a 90-amino acid omega (ω) subunit of RNA polymerase (RNAP), is required for the simultaneous production of KSM and aerial mycelium, and rpoZ-disrupted wild-type S. kasugaensis produces neither KSM nor aerial mycelia. Transcriptional analysis of the biosynthetic genes and forcible expression of kasT in the mutant revealed that the presence of rpoZ, which results in formation of RNAP carrying the ω subunit, facilitates initiation of kasT transcription and is thus crucial for KSM production.

Étude de l'activité antifongique de divers extraits de cannelle

Objective. – This study was undertaken to determine the antifungal activity of cinnamon bark. Material and methods. – Extract from cinnamon with water, hexan, methanol and ethanol were tested on fungi using the method of microtitration assay. Cinnamon was extracted with water, hexan, methanol and ethanol five times and the extracts of each solvent were tested separately for their antimicrobial activity. The minimal inhibitory concentration (MIC) was determined. The extracts were tested on fungal strains using three different techniques; the agar dilution test for the determination of the active extracts, a microtitration method to determine the minimal inhibitory concentration (MIC) of the extracts on growth of yeasts and finally a macrodilution test allowing the evaluation of the extracts on the mycelial mass production by the fungal strains. Results. – The results showed that all the extracts displayed antifungal activity on yeasts. In addition, the determination of the MIC of the active extracts revealed different levels of action. However, the MIC was not influenced by the number of extractions and the fifth extract was as inhibiting as the first one. Finaly, statistical analysis revealed that the hexanic extract was the most active with the MIC varying from 2% (v/v) to 6.2% (v/v), followed by the methanol and water extracts whose the MIC ranged from 2.5% (v/v) to 12.5% (v/v), and the ethanolic extract whose MIC ranged from 5% (v/v) to 12.5% (v/v). Preliminary tests showed that almost all the extracts displayed antifungal activity on moulds. Evaluation of the effects of mycelial production showed that the hexanic extract had the best antifungal effect with a concentration of 10%, and that all 5 extracts were able to totally inhibit the growth of all the species tested. These observations were confirmed by a statistical analysis of variance which revealed that Penicillium cyclopium was the most sensitive mould followed by Aspergillus parasiticus, A. niger and finally A. flavus. Conclusion. – Among the different extracts of cinnamon studied, hexanic extracts were shown to be the most active on the yeasts and moulds tested.

Antifungal activities of actinomycete strains associated with high-altitude sagebrush rhizosphere

The antifungal-producing potential of actinomycete populations from the rhizosphere of low-altitude sagebrush, Artemisia tridentata, has been examined. In a continued investigation of new sources of antifungal-producing microorganisms, this study examined the antifungal-producing potential of actinomycetes from the rhizosphere of high-altitude A. tridentata. With high-altitude sagebrush, rhizosphere soil actinomycete numbers were one to four orders of magnitude higher than those found in nonrhizosphere bulk soils and different from those found with the low-altitude plants. A total of 122 actinomycete isolates was screened against nine fungal species and six bacterial species for the production of antimicrobial compounds. Four rhizosphere isolates, Streptomyces amakusaensis, S. coeruleorubidus, S. hawaiiensis and S. scabies, showed broad-spectrum antifungal activity against three or more fungal species in plate assays. In liquid antagonism assays, mycelium production by Aspergillus niger was reduced by up to 50% by two of the actinomycete isolates. These results demonstrate the potential of rhizosphere microbiology in the search for new antimicrobials.

Quantitative analysis of total mycotoxins in metabolic extracts of four strains of Bipolaris sorokiniana ( Helminthosporium sativum)

The production of total mycotoxins by four strains (3, 5, 8, and 18) of Bipolaris sorokiniana was analyzed using ethyl acetate and ethyl ether as solvents. Physiologically, strain 3 was the best one for the production of mycelium, whereas strain 5 was the best one for the production of total mycotoxins. According to HAT-FTIR spectroscopy, the composition of ethyl ether was more complex, allowing for the identification of OH and CO axial stretching and CH 3 angular deformation present in prehelminthosporol and prehelminthosporolactone.

식물유래 물질이 뽕나무버섯(Armillaria mellea) 균사체 생장 및 혈전분해 활성에 미치는 영향

뽕나무버섯 균사체의 생산 및 혈전분해활성을 증대시키고자 배양기질에 7종의 식물체추출물을 첨가하여 증식시킨 결과 가시오가피 뿌리, 유근피, 홍삼박추출물의 첨가가 균사체 중식에 양호하였으나 인삼추출물 첨가에 의해서 유의적으로 증식이 억제되었다. 또한 가시오가피 가지, 유근피, 홍삼박추출물 첨가에 의하여 단백질분해 활성이 무첨가구보다 <TEX>$36.8{\sim}46.1%$</TEX> 정도 증가되어졌으며 옻피, 가시오가피 가지, 홍삼박 첨가구의 혈전분해 활성은 각각 0.70, 0.71, 0 73 plasmin <TEX>$unit/200\;{\mu}g$</TEX> protein으로 무첨가구의 0.44 plasmin <TEX>$unit/200\;{\mu}g$</TEX> protein에 비하여 <TEX>$59{\sim}65%$</TEX> 증가시킬 수 있었다. 뽕나무버섯 균사체의 조효소는 fibrinogen의 <TEX>$A{\alpha}-chain$</TEX>에 대해 높은 분해특성을 가지고 있었을 뿐만 아니라 무첨가구가 fibrinogen의 모든 단위체를 완전 분해시 까지 3시간이 소요되었던 반면 홍삼박 첨가구는 2시간 후 모든 단위체가 분해되어 대조구보다 높은 활성을 나타내었다. 현미경을 통한 관찰에서 역시 홍삼박 추출물첨가구가 무첨가구보다 높은 분해 활성을 보였다. To increase the fibrinolytic activity and production of mycelium, extracts of 7 plant species were supplemented to the growth media of Armillaria mellea, and mycelial growth and enzymatic activity in the mycelium extracts of A. mellea were estimated. The mycelial production of A. mellea was slightly increased by adding ASH-R, UDVN or RGR extract, whereas KG extract significantly affected the growth. Supplement of ASH-S, UDVN and RGR extracts increased proteolytic activity from 36.8 to 46.1% Fibrinolytic activity was increased to <TEX>$50{\sim}65%$</TEX> by supplement with RVS, ASH-S and RGR extracts, respectively. Enzyme extracts of the fungus grown with RGR extract supplement degraded all chains of fibrinogen within 2 hours, whereas control was required 3 hours. Degradation of fibrin fragments by the enzyme extracts was also observed through microscopy.

Hyphal growth and mycorrhiza formation by the arbuscular mycorrhizal fungus Glomus claroideum BEG 23 is stimulated by humic substances

Effects of humic substances (humic acid or fulvic soil extract) or saprophytic microorganisms (Paecilomyces lilacinus and an unidentified actinomycete) on growth of mycelium and mycorrhiza formation by Glomus claroideum BEG23 were studied in a hydroponic system. Humic substances stimulated root colonization and production of extraradical mycelium by the mycorrhizal fungus. Both humic and fulvic acids tended to decrease populations of culturable bacteria and fungi in the cultivation system, indicating a moderately antibiotic activity. The addition of saprophytic microorganisms able to use humic substances to the cultivation system further stimulated the development of the mycorrhizal fungus. However, stimulation of G. claroideum was also observed when the saprophytic microorganisms were heat-killed, suggesting that their effect was not linked to a specific action on humic substances. The results indicate that humic substances may represent a stimulatory component of the soil environment with respect to arbuscular mycorrhizal fungi.

Alternative products in the "in vitro" inhibition of Sclerotinia sclerotiorum

The white mold, caused by Sclerotinia sclerotiorum, is a very important disease in tomato crops. The objective of this work was to study the effect of plant extracts, animal residues and industrial by-products extracts on the fungus in vitro growth. Treatments consisted of different concentrations of pyrolignous oil, neem oil, monosodium glutamate, sewage sludge and organic compost [coffee residue (50%) coal residue (10%), maize residue (25%), poultry waste (12.5%), poultry meal (2.5%)]. Positive control consisted of Petri dishes with PDA medium and negative control treatment consisted of PDA medium with procymidone. Fungus colonies were incubated at 22ºC and light intensity of 260 lux. Variables such as mycelium growth rate, sclerotia production, and viability 7 and 17 days after the transfer of mycelium disc to neon media were assessed. The extract of organic compost at 30% was effective in controlling mycelial growth and sclerotia production. This treatment, as well as neem oil at 0.5% increased soil respiration.

Influence of culture media and environmental factors on mycelial growth and pycnidial production of Sphaeropsis pyriputrescens

Sphaeropsis pyriputrescens, the causal agent of Sphaeropsis rot of pears and apples, is a recently described species. In this study the effects of culture media, temperature, water potential, pH and light on mycelial growth and pycnidial production of S. pyriputrescens were evaluated. Apple juice agar and pear juice agar were most suitable for mycelial growth of all six isolates tested. Cornmeal agar was not suitable for either mycelial growth or pycnidial production. The fungus grew from −3 to 25 C, with optimum growth at 20 C and no growth at 30 C. The fungus grew at water potential as low as −5.6 MPa on potassium chloride-amended potato-dextrose agar (PDA). Hyphal extension was not observed at −7.3 MPa after 10 d incubation, but growth resumed when the inoculum plugs were placed on PDA. The fungus grew at pH 3.3–6.3 and optimum growth was at pH 3.3–4.2. No mycelial growth was observed at pH above 7.2 after 10 d incubation, but growth resumed when the inoculum plugs were transferred onto PDA. Regardless of medium tested, few pycnidia formed at 20 C in the dark. Pycnidial production was enhanced significantly by fluorescent light, but continuous light appeared to reduce pycnidial production, depending on the medium. Oatmeal agar (OMA) was most suitable for production of pycnidia and conidia. Pycnidia that formed on 3 wk old OMA cultures at 20 C under 12 h light/12 h dark produced abundant conidia, and the technique is recommended for inoculum production.