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1.
Ana-Flora D. Vasconcelos Robert F. H. Dekker Aneli M. Barbosa Luzia Paccola-Meirelles 《Mycoscience》2001,42(6):543-548
Three species of botryosphaeriaceous fungi,Botryosphaeria sp. isolate MAMB-5,Botryosphaeria ribis andLasiodiplodia theobromae, were compared for the production of pycnidia and laccases. Laccases were produced both intra- and extra-cellularly when
the fungi were cultivated on basal medium in the presence and absence of veratryl alcohol, withBotryosphaeria sp. MAMB-5 showing the highest enzyme titres. Electrophoretic examination of intracellular marker proteins (esterases and
phosphatases) and laccases indicated that the three species were genetically distinctly different, although the laccase zymograms
for the three fungi showed similarity. The production of pycnidia occurred under continuous lighting at 28°C, but conditions
differed among the three fungal species. Production could be induced on artificial media (potato-dextrose and oat agar) under
stress-induced conditions where the mycelium was stimulated by physical abrasion, and in the case ofBotryosphaeria sp. isolate MAMB-5 on eucalypt woodchips. Evidence is presented that veratryl alcohol facillitated the secretion of intracellular-localised
laccases into the extracellular medium. 相似文献
2.
E. V. Morozkina A. V. Kurakov A. N. Nosikov E. V. Sapova N. P. L’vov 《Applied Biochemistry and Microbiology》2005,41(3):254-258
Production of nitrate reductase was studied in 15 species of microscopic fungi grown on a nitrate-containing medium. Experiments were performed with Fusarium oxysporum 11dn1, a fungus capable of producing nitrous oxide as the end product of denitrification. Moreover, a shift from aerobic to anaerobic conditions of growth was accompanied by a sharp increase in the activity of nitrate reductase. Studies of nitrate reductase from the mycelium of Fusarium oxysporum 11dn1, grown under aerobic and anaerobic conditions, showed that this enzyme belongs to molybdenum-containing nitrate reductases. The enzymes under study differed in the molecular weight, temperature optimum, and other properties. Nitrate reductase from the mycelium grown under aerobic conditions was shown to belong to the class of assimilatory enzymes. However, nitrate reductase from the mycelium grown anaerobically had a dissimilatory function. An increase in the activity of dissimilatory nitrate reductase, observed under anaerobic conditions, was associated with de novo synthesis of the enzyme.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 3, 2005, pp. 292–297.Original Russian Text Copyright © 2005 by Morozkina, Kurakov, Nosikov, Sapova, Lvov. 相似文献
3.
Aerobacter aerogenes No. 505 isolated from soil by Uyeda produced l-valine extracellularly by an aerobic shaking culture. Under anaerobic conditions the production of this amino acid was inhibited while lactic acid as well as a small amount of alanine were produced. The changes in ORP during the incubation under both conditions were investigated. When l-valine was the main product under aerobic conditions the ORP showed a constant value (rH 8.0) from 16 to 40 hr after inoculation. But when lactic acid was the main product and alanine was produced as the only amino acid under anaerobic conditions, the ORP drifted to rH 0 (zero). The phenomenon of the conversion of fermentation was shown clearly by the ORP of the culture broth.The endpotentiai of lactic acid fermentation by Rhizopus G-36 was rH 13 to 14 when measured in the presence of trace amounts of redox dye mixtures. Without dyes, the rH was 18 to 22 and this fungal culture was slower in reaching endpotentials than bacterial cultures. It was postulated that the amount of redox substances exhibiting electromotive activity was not sufficient in this culture.rH value 13 to 14 was not obtained under such conditions that lactic acid was not produced; that is in a medium with higher concentration of the nitrogen source in the presence of Fe2+ and Zn2+, or in a medium containing acetate in place of glucose as the carbon source.Mycelia of Rhizopus G-36 after 36 hr-culture produced lactic acid even in the absence of oxygen. But unexpectedly, the ORP under anaerobic secondary culture was exactly the same as that in the aerobic shaking culture (rH 13.2).A method for homogenization of the culture without secondary oxidation was improved. The ORP of anaerobically homogenized cultures was rH 11, and was thought to be due to the activities of all redox systems in the mycelium.The respiration system of this strain was switched from cytochrome system to flavin system at the point of change in KGN-sensitivity. The ORP of this strain may be influenced by respiration through the flavin system. 相似文献
4.
All four fungi studied attained approximately the same dry weight of mycelium in starch-yeast extract medium. Only about one-fourth the amount of mycelia was produced in yeast extract alone (starch omitted). However, the initial growth rate ofH. grisea var.thermoidea was greater than the other three fungi. Extracellular amylase was produced by all four fungi, butH. lanuginosa produced 8 to 12 times as much as the other three. Maximum extracellular amylase was found before autolysis with these three fungi, but after autolysis withH. lanuginosa. Extracellular amylase was detected in YE medium (lacking starch), but in very low amounts (approximately one-eighth the amount observed as when starch was present). Increasing the amount of starch in the medium increased extracellular amylase. However, when the starch concentration was kept constant, increasing the concentration of yeast extract had no effect on extracellular amylase.Contribution No. 59 from the Botany Section, The Department of Biology. Portion of a thesis presented by the senior author in partial fulfillment for the M.S. degree. 相似文献
5.
Edible mushroom fungi in the genera Lyophyllum, Tricholoma, Leucopaxillus, Suillus, Rhizopogon, Lactarius, and Morchella were tested for mycorrhization with Pinus densiflora in vitro. Most of the tested fungi in the genera Lyophyllum, Tricholoma, Suillus, Rhizopogon, and Lactarius formed ectomycorrhizas 2–4 months after fungal inoculation. Mycorrhizal seedlings were then acclimatized in open-pot soil
under growth-chamber conditions. Almost all mycorrhizal seedlings sustained their symbiont and developed new mycorrhizas for
8–9 months after transplantation. Under these conditions, more than half of the tested species formed primordia and Tricholoma flavovirens, Rhizopogon rubescens, and Lactarius akahatsu developed basidiocarps with young host plants.
Accepted: 28 November 2000 相似文献
6.
Molecular diversity of fungi from ericoid mycorrhizal roots 总被引:6,自引:0,他引:6
In order to investigate the diversity of fungal endophytes in ericoid mycorrhizal roots, about 150 mycelia were isolated from surface-sterilized roots of 10 plants of Calluna vulgaris. Each mycelium was reinoculated to C. vulgaris seedlings under axenic conditions, and the phenotype of the plant-fungus association assessed by light and electron microscopy. Many isolates that were able in vitro to produce typical ericoid mycorrhizae did not form reproductive structures under our culture conditions, whereas others could be identified as belonging to the species Oidiodendron maius. Morphological and molecular analysis of the fungal isolates showed that the root system of a single plant of C. vulgaris is a complex mosaic of several populations of mycorrhizal and non mycorrhizal fungi. PCR-RFLP techniques, used to investigate the mycorrhizal endophytes, revealed up to four groups of fungi with different PCR-RFLP patterns of the ITS ribosomal region from a single plant. Some of the mycorrhizal fungi sharing the same PCR-RFLP pattern showed high degree of genetic polymorphism when analysed with the more sensitive RAPD technique; this technique may prove a useful tool to trace the spread of individual mycorrhizal mycelia, as it has allowed us to identify isolates with identical RAPD fingerprints on different plants. 相似文献
7.
Ludmila Šilhánková 《Folia microbiologica》1966,11(1):29-38
Visible region of an absorption spectrum was followed in cells of original strains and of rough mutants ofSaccharomyces cerevisiae andS. cerevisiae var.ellipsoideus. It was found that there are no substantial differences in relative content of cytochromesb andc in aerobically grown rough and smooth yeast forms, in spite of the fact that both forms differ substantially in the metabolic
oxygen quotient. If the cytochromes present were not reduced in washed cells by dithionite or by substrate addition, the rough
forms exhibited a lower cytochrome b:c ratio than the smooth forms. Under anaerobic conditions of cultivation, the rough forms retained a typical aerobic spectrum,
lacking, however, the cytochromea and a3 band; the ratio of cytochromesb andc was changed in favour of cytochromeb (from the original 1.7: 1 up to 3.4: 1). The inability of the rough mutants to produce anaerobic cytochrome spectrum represented
by cytochrome b1 was connected with their inability to reproduce under anaerobic conditions. 相似文献
8.
Aflatoxin: A metabolic product of several fungi 总被引:8,自引:0,他引:8
Summary Culture extracts produced by 107 fungi isolated from corn grains were assayed by thin layer chromatography for aflatoxin. Certain isolates ofAspergillus flavus, A. niger, A. parasiticus, A. ruber, A. wentii, Penicillium citrinum, andP. variabile produced aflatoxin.Penicillium frequentans andP. puberulum elaborated this toxin only in trace amounts. Bioassays of extracts from 4 of these fungi showed that only the extract fromA. parasiticus was highly toxic. 相似文献
9.
α-mannosidase and mannanase of some wood-rotting fungi 总被引:1,自引:1,他引:0
Cultivation media from 11 wood-rotting fungi contained α-mannosidase and mannanase activity. α-Mannosidase was studied in
more detail inPhellinus abietis and mannanase was studied more intimately in basidiomycetesPhellinus abietis, Trametes sanguinea andPholiota aurivella. Suitable cultivation conditions and optimum conditions for the production of α-mannosidase and mannanase were determined.
Both enzymes are constitutive; mannanase is extracellular, α-mannosidase was found in both mycelium and cultivation medium. 相似文献
10.
Tytti Sarjala 《Mycorrhiza》1999,8(5):277-281
The abilities of three ectomycorrhizal fungi, Paxillus involutus, Suillus
variegatus and Lactarius rufus, to utilize organic and inorganic nitrogen sources were determined by measuring the growth and endogenous free polyamines
(putrescine, spermidine and spermine) of pure culture mycelium. Differences were found in the utilization of the nitrogen
sources and in the polyamine concentrations between the fungal species and between isolates of L. rufus. All the fungi grew well on ammonium and on several amino acids. Endogenous polyamine levels varied with the nitrogen source.
Spermidine was commonly the most abundant polyamine; however, more putrescine than spermidine was found in P. involutus growing on inorganic nitrogen or arginine. Low amounts of spermine were found in S. variegatus and some samples of L. rufus. None or only a trace of spermine was found in P. involutus mycelium. In all fungi, putrescine concentrations were higher with ammonium than with the nitrate treatment. The total nitrogen
content of peat did not determine the ability of L. rufus strains isolated from peatland forest sites to utilize organic nitrogen.
Accepted: 27 November 1998 相似文献
11.
The cultivation of some ectomycorrhizal fungi growing in bioreactors under submerged aerobic conditions was modified by regulating the cultivation parameters and determining the optimum duration of the process. For this goal, the active mycelium was determined by quantifying its ergosterol content. Lactarius deliciosus (strain LDF5) and Suillus mediterraneensis (strain 35 AM) were cultivated in a BRAUN Biostat®B bioreactor under the following fermentation conditions: 23 °C, pH 5.5, 60% dissolved oxygen, 100 rpm stirring, and 1.2‐‐2 L/min air flow. In addition, several cultivation conditions were assayed for L. deliciosus. During the fermentation cycle, samples were taken at different times. Ergosterol was extracted and quantified using high‐performance liquid chromatography (HPLC). The quantity of ergosterol in L. deliciosus increased with the age of the culture up to 4.7 μg/mg (17‐day‐old culture). In the case of S. mediterraneensis, this quantity increased up to day 11 of the cultivation, and then it decreased. Three days after the addition of fresh medium, a maximum of 8.9 μg/mg was reached. On the other hand, the highest ergosterol content in L. deliciosus (6.3 μg/mg) was obtained using MMN medium with the addition of agar. 相似文献
12.
Heavy-Metal Stress and Developmental Patterns of Arbuscular Mycorrhizal Fungi 总被引:6,自引:0,他引:6
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The rate of global deposition of Cd, Pb, and Zn has decreased over the past few decades, but heavy metals already in the soil may be mobilized by local and global changes in soil conditions and exert toxic effects on soil microorganisms. We examined in vitro effects of Cd, Pb, and Zn on critical life stages in metal-sensitive ecotypes of arbuscular mycorrhizal (AM) fungi, including spore germination, presymbiotic hyphal extension, presymbiotic sporulation, symbiotic extraradical mycelium expansion, and symbiotic sporulation. Despite long-term culturing under the same low-metal conditions, two species, Glomus etunicatum and Glomus intraradices, had different levels of sensitivity to metal stress. G. etunicatum was more sensitive to all three metals than was G. intraradices. A unique response of increased presymbiotic hyphal extension occurred in G. intraradices exposed to Cd and Pb. Presymbiotic hyphae of G. intraradices formed presymbiotic spores, whose initiation was more affected by heavy metals than was presymbiotic hyphal extension. In G. intraradices grown in compartmentalized habitats with only a portion of the extraradical mycelium exposed to metal stress, inhibitory effects of elevated metal concentrations on symbiotic mycelial expansion and symbiotic sporulation were limited to the metal-enriched compartment. Symbiotic sporulation was more sensitive to metal exposure than symbiotic mycelium expansion. Patterns exhibited by G. intraradices spore germination, presymbiotic hyphal extension, symbiotic extraradical mycelium expansion, and sporulation under elevated metal concentrations suggest that AM fungi may be able to survive in heavy metal-contaminated environments by using a metal avoidance strategy. 相似文献
13.
H2-producing bacteria were isolated from anaerobic granular sludge. Out of 72 colonies (36 grown under aerobic conditions and
36 under anaerobic conditions) arbitrarily chosen from the agar plate cultures of a suspended sludge, 34 colonies (15 under
aerobic conditions and 19 under anaerobic conditions) produced H2 under anaerobic conditions. Based on various biochemical tests and microscopic observations, they were classified into 13
groups and tentatively identified as follows: From aerobic isolates,Aeromonas spp. (7 strains),Pseudomonas spp. (3 strains), andVibrio spp. (5 strains); from anaerobic isolates,Actinomyces spp. (11 strains),Clostridium spp. (7 strains), andPorphyromonas sp. When glucose was used as the carbon substrate, all isolates showed a similar cell density and a H2 production yield in the batch cultivations after 12h (2.24–2.74 OD at 600 nm and 1.02–1.22 mol H2/mol glucose, respectively). The major fermentation by-products were ethanol and acetate for the aerobic isolates, and ethanol,
acetate and propionate for the anaerobic isolates. This study demonstrated that several H2 producers in an anaerobic granular sludge exist in large proportions and their performance in terms of H2 production is quite similar. 相似文献
14.
Ten white-rot fungi have been screened for the production of ligninase, manganese peroxidase and laccase. Although the fungi
degraded lignin efficiently, they significantly differed in the occurrence of individual ligninolytic enzymes. Based on the
enzyme pattern produced under N-limited conditions, the fungi can be divided into the following four groups:1. ligninase-manganese peroxidase-laccase group,2. ligninase-manganese peroxidase group,3. manganese peroxidase-laccase group,4. laccase group. 相似文献
15.
Among thirteen thermophilic fungal strains,viz. Malbranchea pulchella var.sulfurea, Sporotrichum thermophile, Thielavia terrestris, Humicola insolens andAcremonium alabamensis produced high levels of xylanolytic enzymes. The secretion of xylanolytic enzymes was higher in wheat straw medium than in
wheat straw hemicellulose. All fungi utilized xylose as the carbon source. However,Mucor pusillus, Torula thermophila andSporotrichum thermophile consumed 90–93% of xylose provided in the medium while others utilized 51–83%. The consumption of glucose by the fungi was
high in comparison with that of xylose. Of all the treatments tried, xylose isomerase yield was highest when the mycelium
ofHumicola insolens was homogenized with sand. The synthesis of xylose isomerase was very high in wheat straw hemicellulose as compared with
that in xylose and glucose. 相似文献
16.
Furukawa Toshiko; Koga Jinichiro; Adachi Takashi; Kishi Kunihei; Syono Kunihiko 《Plant & cell physiology》1996,37(7):899-905
In a study of various phytopathogenic fungi, we found that fungithat belong to the genus Rhizoctonia produce IAA efficientlyfrom tryptophan. R. solani Kühn MAFF-305219, in particular,produced large amounts of tryptophol (Tol), which was assumedto be a specific by-product of the indole-3-pyruvate (IPy) pathway,in addition to IAA. Therefore, this fungus seemed suitable foranalysis of the function and the regulation of the biosynthesisof auxin by a fungal pathogen. Under normal aerobic conditions,the ratio of IAA to Tol synthesized by this strain was higherthan that under less aerobic conditions. In metabolic studieswith various indole derivatives, R. solani converted L-tryptophanand indole-3-acetaldehyde to IAA and Tol, but other indole derivativeswere scarcely metabolized. These results suggest that both IAAand Tol are synthesized from tryptophan through the IPy pathwayin Rhizoctonia. (Received May 27, 1996; Accepted July 8, 1996) 相似文献
17.
Five hundred isolates of different xerophilic and non-xerophilic fungi belonging to 10 genera and 74 species were screened
for alditol (sugar alcohol) accumulation. Ninety-two of the isolates failed to grow on a salt medium, most of the isolates
(408) produced alditols; 348,44 and 16 of them produced low, moderate and high levels of alditols, respectively. The high
alditol producers belonged to five species ofAspergillus, six species ofEurotium andFennellia flavipes. Glycerol andd-mannitol were the main constituents of alditol pools of the 16 high alditol producers.d-Arabinitol andmeso-erythritol were also formed but at low concentrations by several of the tested isolates. 相似文献
18.
Anna Jarosz-Wilkołazka Marcin Grąz Bianca Braha Sieglinde Menge Dietmar Schlosser Gerd-Joachim Krauss 《Biometals》2006,19(1):39-49
The effect of cadmium (Cd) on fungal growth, Cd bioaccumulation and biosorption, and on the formation of potential heavy metal
response indicators such as thiols, oxalate, and laccase was investigated in the white rot fungi Cerrena unicolor andAbortiporus biennis. Only the highest Cd concentration employed (200 μM) inhibited growth of C. unicolor, whereas already lower Cd concentrations caused decreasing mycelia dry weights in A. biennis. Cd biosorption onto the mycelial surface was the predominant Cd sequestration mechanism in C. unicolor. Surface-bound and bioaccumulated Cd concentrations were essentially in the same range in A. biennis, leading to considerably higher intracellular Cd concentrations in A. biennis than in C. unicolor. Oxalate and laccase were produced by both of the fungal strains and their extracellular levels were elevated upon Cd exposure.
Oxalate concentrations and laccase titres were considerably higher in C. unicolor than in A. biennis. Both fungi responded to increasing Cd concentrations by increasing intracellular amounts of thiol compounds (cysteine, γ-glutamylcysteine, glutathione in both its reduced and oxidized form) but Cd application increased the amounts of thiols to
a higher extend in A. biennis. Taken together, these species-specific responses towards Cd suggest that C. unicolor possesses a more efficient system than A. biennis to keep intracellular Cd concentrations low. 相似文献
19.
Summary A collection of 159 strains of black yeasts obtained from a number of culture collections and a wide variety of substrata was studied. Morphologically, four species were present:Phialophora jeanselmei with a mycelium that produced radulaspores and also phialides;Sclerophoma pithyophila, which produces pycnidial initials and sometimes pycnidia in culture; and two species ofAureobasidium, A. pullulans with wide mycelium and large radulaspores, andA. mansonii, which produces narrow mycelium and small radulaspores.Physiologically, these species form two distinct groups:A. mansonii andP. jeanselmei, which grow slowly; andA. pullulans andS. pithyophila, which grow more rapidly. Except for rate of growth, there was little difference between these species in their abilities to use the carbon and nitrogen sources tested. None produced significant capabilities for fermentation in the sugars and at the pH level tested. All varied in their response to a technique designed to measure amounts of growth by turbidometry.The black yeasts, especiallyA. pullulans, are a highly polymorphic group of organisms capable of growing in a wide variety of locations. For the most part they are capable of using the simpler organic compounds found in nature, which indicates they apparently act largely on terminal or subterminal products of decay in the final stages of the mineralization of organic compounds. 相似文献
20.
A collection of 36 fungi cultivated by leaf-cutting ants has been established at The New York Botanical Garden. These fungi grow on a variety of natural media and on a synthetic medium with mineral salts, dextrose, casein hydrolysate, purine and pyrimidine bases and vitamins. Tests of the fungi for antibacterial activity were all negative againstStaphylococcus aureus andEscherichia coli. Only four isolates of ant fungi, each cultivated by a different species of ant, produced basidiocarps on oatmeal agar. Taxonomic studies indicate that these belong to the same species of fungus (Lepiota sp.). Eighteen isolates produced bromatia characteristic of the form species,Attamyces bromatificus Kreisel, one produced a mycelium with clamp connections, and thirteen produced sterile mycelia without clamped hyphae and without bromatia. 相似文献