Effect of a preparation from Chaetomium fungi on the growth of phytopathogenic fungi

We studied the fungicidal activity of a biological preparation from the fungi of the genus Chaetomium against soil phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The inhibitory effect of the preparation under study depended on its concentration, duration of storage, and growth characteristics of pure cultures of the phytopathogens. The highest (98.8%) inhibitory activity was observed on day 3 of the interaction with Rhizoctonia solani. After a 2-year storage, this preparation was capable of inhibiting the growth of the phytopathogens only at high doses. The preparation precluded the development of bare patch and increased the productivity of potato plants. The preparation may serve as an alternative to chemical fungicides for plant protection.     

The effect of a preparation from Chaetomium fungi on the growth of phytopathogenic fungi

We studied the fungicidal activity of a biological preparation from the fungi of the genus Chaetomium against soil phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The inhibitory effect of the preparation under study depended on its concentration, duration of storage, and growth characteristics of pure cultures of the phytopathogens. The highest (98.8%) inhibitory activity was observed on the third day of the interaction with Rhizoctonia solani. After a 2-year storage, this preparation was capable of inhibiting the growth of phytopathogens only at high doses. The preparation precluded the development of a bare patch but increased the productivity of potato plants. The preparation may serve as an alternative to chemical fungicides for plant protection.     

Meeting a non-host: the behaviour of AM fungi

 Arbuscular mycorrhizal (AM) fungi are obligately biotrophic organisms that live symbiotically with the roots of most plants. The establishment of a functional symbiosis between AM fungi and host plants involves a sequence of recognition events leading to the morphological and physiological integration of the two symbionts. The developmental switches in the fungi are triggered by host signals which induce changes in gene expression and a process leading to unequivocal recognition between the two partners of the symbiosis. It has been calculated that about 80% of plant families from all phyla of land plants are hosts of AM fungi. The remaining plant species are either non-mycorrhizal or hosts of mycorrhizas other than the arbuscular type. Non-host plants have been used to obtain information on the factors regulating the development of a functional symbiosis. The aim of this present review is to highlight present-day knowledge of the fungal developmental switches involved in the process of host/non-host discrimination. The following stages of the life cycle of AM fungi are analysed in detail: spore germination, presymbiotic mycelial growth, differential branching pattern and chemotropism, appressorium formation, root colonization. Accepted: 17 June 1998     

未来的一种生物肥料:丛枝菌根真菌*

丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)存在于几乎所有类型的土壤中,可以与绝大多数被子植物的根共生。大多数农作物、果树、蔬菜、观赏植物和花卉等都能形成丛枝菌根。AMF能促进作物吸收利用矿质养分和水分,提高作物抗逆性和抗病性,改良土壤、提高苗木移栽成活率、促进生长、提高产量和改善品质,并且可用于改善退化生态系统的土壤肥力,维持农林业的可持续发展,将成为一种新型的生物肥料被用于农林业生产。本文讨论了影响菌根侵染率的因素、AMF的生态效应和在生态农业中的应用现状和前景。     

Monitoring the occurrence of indoor fungi in a hospital

BackgroundThere is a lack of standardized protocols for assessing the presence of indoor fungi. It is thus difficult to compare results from different studies or to measure the effect of indoor fungal presence on occupants.AimsThe aim of the present work was to evaluate the presence of airborne fungal propagules within a hospital taking into account the influence of environmental factors.MethodsThe study was conducted in a hospital over a period of two years. Two portable aerobiological samplers were used: one capturing propagules onto a sticky surface, and the other onto a culture medium consisting of Sabouraud dextrose agar in Petri dishes, supplemented with chloramphenicol. Sampling was performed indoors at four sites (two on the ground floor and two on the third floor, each consisting of an open ward and a closed room). Samples were also taken outdoors. The following factors were considered for fungus occurrence: season, weather conditions, number of people present in the wards, the insulation of the indoor sites and the existence of construction works on the two floors. We carried out 60 ten-minute samples, weekly during the spring (24 samples), and fortnightly for the rest of the year (36 samples).ResultsA total of 2456 colony forming units (CFU) were obtained, with mean propagule concentrations of 107 CFU/m³ outdoors and 24 CFU/m³ indoors. 35330 counts were recorded for propagules. The mean concentrations were 2473 propagules/m³ outdoors and 790 indoors. A statistically significant positive correlation was found between the number of people in one of the wards and fungus occurrence, and the occurrence in both ground floor and third floor rooms was positively correlated with outdoor levels. These showed a seasonal pattern with peaks in summer. Indoors, however, the peaks appeared in spring and autumn. Outdoor construction activities affected the propagule loads but not the number of CFU.ConclusionsThe indoor fungus occurrence in the hospital was independent of meteorological conditions and of insulation from outside of the indoor sites selected, but was correlated with the season and number of people in the third floor ward. Outdoor construction activities affected values of indoor propagules, although seasonality could mask their effect.     

Cryophilic fungi to denote fungi in the cryosphere

Fungi are widely distributed in the cryosphere where the habitat is constantly or seasonally covered with snow and/or ice. Fungi normally have different cells in their life cycle; fungal thermal dependence varies according to their life cycle stages and is completely different from that of bacteria. Examples are illustrated to show that the concept of psychrophile by Morita (1975) does not apply to fungi, and we propose a new term “cryophilic fungi” for those that spend a certain life stage or whole life cycle (sexual and/or asexual reproductive stages) in the cryosphere.     

Eccrinales (Trichomycetes) are not fungi, but a clade of protists at the early divergence of animals and fungi

The morphologically diverse orders Eccrinales and Amoebidiales have been considered members of the fungal class Trichomycetes (Zygomycota) for the last 50 years. These organisms either inhabit the gut or are ectocommensals on the exoskeleton of a wide range of arthropods--Crustacea, Insecta, and Diplopoda--in varied habitats. The taxonomy of both orders is based on a few micromorphological characters. One species, Amoebidium parasiticum, has been axenically cultured and this has permitted several biochemical and phylogenetic analyses. As a consequence, the order Amoebidiales has been removed from the Trichomycetes and placed in the class Mesomycetozoea. An affinity between Eccrinales and Amoebidiales was first suggested when the class Trichomycetes was erected by Duboscq et al. [Arch. Zool. Exp. Gen. 86 (1948) 29]. Subsequently, molecular markers have been developed to study the relationship of these orders to other groups. Ribosomal gene (18S and 28S) sequence analyses generated by this study do not support a close association of these orders to the Trichomycetes or to other fungi. Rather, Eccrinales share a common ancestry with the Amoebidiales and belong to the protist class Mesomycetozoea, placed at the animal-fungi boundary.     

Four new species and a new Chinese record of the nectrioid fungi

Four new species belonging to Bionectria, Calonectria, Haematonectria and Neonectria on plant substrates collected from nature reserves in southern and central China are described. Bionectria truncata has smooth perithecia of a flattened to shallow discoid apex, clavate asci with an apical ring, and ellipsoid, smooth to spinulose ascospores. Calonectria dicephalospora is characterized by pyriform perithecia with a warted surface, clavate asci with a simple apex and long, narrow stalk, and fusoid ascospores with a cap-like appendage at each end. Haematonectria lushanensis possesses warted perithecia which are laterally collapsing when dry, cylindrical asci with a simple apex, and ellipsoid, spinulose ascospores. Neonectria dinghushanica is distinguishable by subglobose perithecia with a warted surface, clavate asci, and striate ascospores. Morphological features of these new species are described comprehensively and compared with their related fungi. Neonectria castaneicola is recorded as new to China.     

Microbodies in fungi: a review

Summary Microbodies are ubiquitous organelles in fungal cells, occurring in both vegetative hyphae and spores. They are bounded by a single membrane and may contain a crystalloid inclusion with subunits spaced at regular intervals. Typically, they contain catalase which reacts with the cytochemical stain 3,3-diaminobenzidine to yield an electron-opaque product, urate oxidase,l--hydroxy acid oxidase andd-amino acid oxidase. Their fragility and the necessity to disrupt the tough fungal cell wall before isolating them make them difficult to isolate. Analysis of enzymes in purified or partially purified microbodies from fungi indicates that they participate in fatty acid degradation, the glyoxylate cycle, purine metabolism, methanol oxidation, assimilation of nitrogenous compounds, amine metabolism and oxalate synthesis. In organisms where microbodies are known to contain enzymes of the glyoxylate cycle, they are known as glyoxysomes; where they are known to contain peroxidatic activity, they are known as peroxisomes. In some cases microbodies contain enzymes for only a portion of a pathway or cycle. Thus, they must be involved in metabolic cooperation with other organelles, particularly mitochondria. The number, size and shape of microbodies in cells, their buoyant density and their enzyme contents may vary with the composition of the medium; their proliferation in cells is regulated by the growth environment. The isolation from the same organism of microbodies with different buoyant densities and different enzymes suggests strongly that more than one type of microbody can be formed by fungi.     

Community of wood-destroying fungi as a reflection of the structure and state of a forest

A new approach to the analysis of fungal communities is proposed, with the purpose of indication of the state of ecosystems. The approach is based on the dialectical unity of the parts and the whole, abstraction and concreteness in the light of modern notions of the fractal character of the objective reality. Exemplified by Panholarctic mycocomplex of birch, it is shown that the biota of wood-destroyed fungi is a fractal, the structure of which is an integral reflection of the structure of forest stand developing under different conditions, which is confirmed by the reproducibililty of taxation indices of the stand in the fractal-matrix analysis of groups of wood-destroying fungi. The proposed formulas were tested for the latitudinal-zonal and topological range of forests and can be considered not only as an illustration of the surprising integrity of the universe but also used in ecological activities.     

Knowledge and use of fungi by a mycophilic society of the Venezuelan Amazon

This paper reports on the knowledge and useful applications of various fungi by the Hotï, a recently contacted Native American society inhabiting the Sierra Maigualida region of the Venezuelan Amazon. At least 31 folk taxa of fungi are esteemed as sources of nutrition, powerful media for hunting magic, protective charms against black magic, human medicinal agents, or body adornments. Even though the results presented here probably do not exhaust the total number of species known and used by them, they nevertheless suggest that the Hotï constitute one of the rare mycophilic societies in the Venezuelan Amazon. Further research is needed in order to obtain a more complete picture of the complexity of humanfungi relationships in this society.     

Description of a cellulose-binding domain and a linker sequence from Aspergillus fungi

A family I cellulose-binding domain (CBD) and a serine- and threonine-rich linker peptide were cloned from the fungi Aspergillus japonicus and Aspergillus aculeatus. A glutathione S-transferase (GST) fusion protein comprising GST and a peptide linker with the CBD fused to its C-terminus, was expressed in Escherichia coli. The renatured GST-CBD recovered from inclusion bodies had a molecular mass of 36.5 kDa which agrees with the 29 kDa of the GST plus the calculated 7.5 kDa of the linker with the CBD. The isolated GST-CBD protein adsorbed to both bacterial microcrystalline cellulose and carboxymethyl cellulose. Deletion of the linker peptide caused a decrease in cellulose adsorbance and a higher sensitivity to protease digestion.     

Towards a functional classification of ectomycorrhizal fungi

Ectomycorrhizal (ECM) fungi have previously been divided into two groups (early-stage and latestage) based on their position in ectomycorrhizal succession. This classification has a number of limitations, particularly in the lack of precision in the terminology adopted and its general applicability. Many species cannot be easily assigned to either stage, and the behaviour of some species is modified by environmental conditions. In addition, a number of different mechanisms of ECM succession have been proposed, including the influence of organic matter and root exudates. In this paper, it is suggested that the phenomenon of ECM succession can be explained simply by the relative ability of different fungi to colonize and spread from different sources of inoculum. Epidemiological characteristics, such as the ability to produce mycelial strands or to spread on root systems by secondary infection, may therefore provide a more appropriate basis for a functional classification of ECM fungi. The functionally important characteristics of ECM fungi are discussed.     

Biodiversity and concentration of airborne fungi in a hospital environment

The biodiversity and concentration of airborne fungi were monitored over a period of 6 months in a special-care unit of a hospital. Air sampling was performed in a corridor that was also accessible to visitors and in an adjacent bone-marrow transplantation (BMT) unit using an air sampler and two isolation media. Altogether, 98 fungal species could be identified, among them Aspergillus fumigatus and A. terreus as well as 48 other species reported as potential pathogens. The average contamination values of the corridor air ranged from 124 to 485 cfu m⁻³. Neither the degree of fungal air contamination nor the species composition inside the special care unit differed from those found in the corridor. By means of data obtained with a light-activated sensor, a possible influence of human activities on diurnal changes of fungal propagule concentration was shown. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inventoring the fungi of Panama

Records of fungi in Panama scattered in literature are presented in a preliminary annotated checklist which is published in Panama. It includes 1807 species and subspecific taxa in 646 genera. The data allow to trace more than 100 years of history of mycology in Panama, presented here for the first time. The species richness is analyzed numerically with respect to the systematic position of the species and their ecology. Considering the numbers of records for different regions of Panama, a comparison with numbers of species published for some other neotropical countries, as well as recent experience collecting fungi in Panama, the incompleteness of the checklist is evident. Values of relative species richness of different systematic groups in Panama compared to values of the same groups as known worldwide, show that our knowledge is fragmentary in Panama especially for Agaricales, Uredinales, and some groups of microfungi. We are still in the pioneer phase of mycological investigation in Panama.     

Mutualism is not restricted to tree-killing bark beetles and fungi: the ecological stoichiometry of secondary bark beetles,fungi, and a scavenger

1. All bark beetles are in symbiosis with fungi. Although obligate mutualisms with fungi are common with tree-killing bark beetles (primaries), fungi associated with non-tree-killing bark beetles (secondaries) are usually dismissed as commensals. 2. Using an ecological stoichiometric approach, we show secondaries are also involved in nutrition-based mutualisms, some of which appear obligate, and that differences in symbiont provisioning efficiency have a potent effect on beetle carbon (C): nitrogen (N): phosphorus (P) ratios. 3. Some secondary beetles have high P contents and require efficient P provisioning via fungi, while others have low P contents that may allow them to exploit less efficient fungi or a broader range of species with variable efficiencies. A co-occurring scavenger that feeds on nutrient-poor bark beetle frass (excrement/boring residues) exhibited the lowest phosphorus content yet recorded for an invertebrate. 4. Our results generally support the growth-rate hypothesis that posits differences in C:P and N:P ratios in consumers are due to differential allocation of P to P-rich RNA to support growth. However, while the beetle species that accumulated the most biomass was considerably enriched in P and that with the least biomass was P-poor, one beetle species that was P-rich was also small possibly due to limitation by an element other than P. 5. Our results indicate that fungi are important to a broader range of bark beetles than previously recognised. Additional research is needed to describe how these various symbioses influence forest ecosystems via differential effects of fungi on host beetle fitness.     

Psychrophilic and psychrotrophic fungi: a comprehensive review

This article reviews the comparative diversity of psychrophilic and psychrotrophic fungi, their adaptability mechanisms for survival and potential applications in biotechnology and pharmaceuticals. Fungi are able to grow and survive at low temperature and exist widely in polar and non-polar habitats. These cold regions are known for very low temperature, high ultra violet-B radiation, frequent freeze and thaw cycles and low water and nutrient availability. Most of the fungi adapt to such harsh conditions by evolving various strategies in their metabolism and physiology. Psychrophilic and psychrotrophic fungi are of importance in biotechnological and pharmaceutical fields due to their diverse characteristics developed or evolved due to their adaptation and survival in extreme environments, like; production of cold-active enzymes, pharmaceutical or bioactive metabolites and exo-polysaccharides, have potential for bioremediation and can also be used as biofertilizer.     

Ustomycota,a new division of higher fungi

The ustilaginaceous fungi, traditionally synonymous with the smuts, now include recent taxa derived from the yeasts. Although generally placed next to the rusts, these fungi only superficially resemble the Uredinales-the resistant cell, here termed a ustospore, is not a teliospore and its one or more germ hyphae bear somatic sporidia, not meiotically derived basidiospores. Examination of the ultrastructure of a number of species shows the septa to be basidiomycetously layered but with pores lacking a dolipore/parenthesome complex. Further, inLeucosporidium andRhodosporidium, in which the clamps also have simple pores, the electron microscopic observations admit the interpretation that the ustospore is an encysted proascus. Because the characteristics of these fungi do not allow them to be satisfactorily included among either the Ascomycota or the Basidiomycota, it is proposed to accommodate them in a new taxon of equal rank, the Division Ustomycota. Grateful acknowledgement is made to the Nederlandse Organisatie voor Zuiver Wetenschappelijk Onderzoek (ZWO) for their support of this research. It is also a particular pleasure to thank Professor J. G. H. Wessels and Dr. N. J. W. Kreger-van Rij for their hospitality and to extend my appreciation to the Laboratory of Ultrastructural Biology for use of facilities. A particular note of gratitude is made to Hans Cappon for the preparation of the drawings. This study was made during a leave of absence from North Carolina State University.     

产脂肪酶真菌的选育及酶学性质研究

从富含油脂土壤中筛选出一株产碱性脂肪酶酶活达6.40U/mL的真菌菌株,经显微形态及ITS序列分析鉴定为产黄青霉Penicillium chrysogenum,该菌株命名为Penicillium chrysogenum J23。该菌的最佳产酶培养条件为：蔗糖1.0%、蛋白胨2.0%、橄榄油1.0%、MgSO4·7H2O 0.05%、接种量1.0%、初始pH 9.0、摇床转速200r/min、30℃培养48h。其所产脂肪酶的最适反应温度与pH分别为33℃和7.5,在pH6.0－10.0酶具有良好的稳定性,在50℃处理2h仍可保持30%以上的酶活力,50mmol/L的Ca2+、Mg2+、K+分别对酶有较强激活作用,而50mmol/L的Fe2+、Mn2+、Cu2+、Pb2+、Li2+对酶则有不同程度的抑制作用。     

Analogous effects of arbuscular mycorrhizal fungi in the laboratory and a North Carolina field

Although arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of plants, the mutualism has rarely been tested in nature. In experiments designed to explore the ecological relevance of associations between different fungal and plant species in a natural environment, plant species were infected with different species of fungi and grown in separate trials in the laboratory and a North Carolina (USA) field. The benefits to plants varied dramatically as plant species were grown with different species of AM fungi. Effects of mycorrhizal fungi in nature were generally correlated to effects in the growth chamber, suggesting that laboratory data do reflect dynamics between plants and AM fungi in the field. Initial size at transplant and experimental block were also significant predictors of plant growth in the field. Correlation statistics between laboratory and field data were weaker when analyses involved plant species less responsive to infection by any AM fungus, suggesting that the response of a species to inoculation is a good predictor of its sensitivity to specific AM fungi in the field. AM fungal identity appears to influence the growth and reproduction of plants in the field.