Comparative Physiology of Respiration in Aquatic Fungi

A comparative study of terminal respiration was undertaken in five genera of aquatic fungi in the Leptomitales. The cytochrome system in this group of fungi contained cytochrome a-a₃ (605 nm), cytochrome c (551 nm), cytochrome b (557 nm), and cytochomo b (564 nm). A representative of each of three aerobic genera, Leptomitus, Apodachlya, and Sapromyces, had a total cytochrome content of about 2×10^?10 mol/mg dry weight. An endogenous respiration rate of 21 μl O₂ uptake/ (h × mg dry weight) at 21.7°C was found in Leptomitus and Apodmhlya and 14 in Sapromyces. The strain belonging to the fermenlative genus Mindeniella had approximately one-third of the total cytochrome content and one-third of the endogenous respiration rate observed in Leptomitus and Apodachlya. Mindeniella and Sapromyces contained less total cytochrome when grown under reduced oxygen tension than when grown in air. Only about one-half of the b-type cytochrome was redueible by endogenous substrates. Both cytochrome a₃ and an unidentified pigment bound CO. The endogenous respiration of Leptomitus, Apodachlyo, and Sapromyces was strongly Inhibited by sodium cyanide, sodium azide, antimycin A, and sodium fluoroacetate.     

Studies of Aquatic Fungi. XIII. Mycoflora of the River Czarna Hańcza and its Tributary,the River Marycha

The authors investigated the mycoflora and the environmental factors in the River Czarna Hańcza (10 stations) and its tributary River Marycha (1 station) as well as Lakes Hańcza (2 stations) and Wigry (2 stations) on the occurrence of various aquatic fungi. At the stations investigated the presence of 45 aquatic fungi species was noted. The following fungi, up to now unknown in Poland, were found: Monoblepharis hypogyna, Rozellopsis inflata, Cladolegnia eccentrica, Apostemidium guernisaci, Anguillospora gigantea, Geniculospora grandis, Clavariopsis aquatica, Lemonniera aquatica and Lemonniera terrestris.     

Observations on the fine structure of Chlamydobotrys stellata,with particular reference to its unusual chloroplast structure

Summary Eight species of Olpidium are reported from freshwater algae and from soils in Iceland. Similarities between Olpidium endogenum and O. entophytum are discussed. On the basis of the specimens at hand and the substrates in which they occur, O. zygnemicola and O. spirogyrae are reduced to synonymy with O. entophytum and O. endogenum respectively. Olpidioid fungi in Oedogonium and sterilized pine pollen are tentatively assigned to the doubtfully distinct species O. saccatum and O. utriculiforme. Olpidium pendulum, O. luxurians, and O. longicollum occur in pine pollen bait in gross water cultures of soil. These three species are only doubtfully distinct entities. Olpidium rhizophlyctidis is reported for the first time from Iceland.     

Comparative Physiology of Respiration in Aquatic Fungi II. The Saprolegniales, Especially Aphanomyces astaci

The endogenous respiration of six members of Saprolegniaceae (Oomycetes), Saprotegnia sp., Thraustotheca sp., Achlya sp., Dichtyuchus sp., Aphanomyces euteiches, and A. astaci were studied in the presence and in the absence of exogenous substrate using conventional manometric techniques. Glucose stimulated the rate of oxygen uptake of unstarved mycelia to some extent in all the fungi. Attempts to increase the weak stimulation of respiration by glucose in A. astaci were not successful. The respiratory quotients of the fungi tested were usually in the range of 0.7 to 0.9 during endogenous respiration, and addition of glucose increased these values more than expected. L-leucine and L-glutamic acid stimulated respiration of A. astaci only when the fugus was starved, and acetic acid and butyric acid were inhibitory. Fructose and acetic acid increased respiration in starved mycelium of A. euteiches while L-leucine and L-glutamic acid had little effect. Antimycin A, HOQNO, HCN, and fluoroacetate strongly inhibited endogenous oxygen uptake by A. astaci. Amytal and azide were also markedly inhibitory while rotenone and CO had little effect. DNP and diphenylamine inhibited respiration at a high concentration but at a lower concentration DNP was stimulatory. In contrast the respiration of Saprolegnia sp. was resistant to cyanide, antimycin A, and HOQNO. Spectrophotometric observations on homogenized mycelia of Saprolegnia sp. and of A. astaci indicated the presence of cytochrome c (551 nm), two b-type cytochromes (557 and 564 nm) and cytochrome a-a₃ (605 nm) all in approximately equimolar concentrations. In both strains CO combined with cytochrome a₃ and an unidentified pigment. A remarkable similarity in the cytochrome system seems to exist between these two strains and some members of the Leptomitales.     

Fungi associated with sorghum seeds

Summary A study of the external and internal fungi associated with different varieties ofSorghum seeds has been made. The varieties tested included eighteen local varieties and twelve newSorghum varieties obtained from the Rockefeller Foundation. The external fungi were studied by preparing suspensions of superficial fungi and growing on potato dextrose agar. The internal fungi were studied by planting surface sterilized seeds on P.D.A. and pure cultures of all these fungi were prepared.The external fungi found to be associated with the different varieties included different species ofPhycomyces, Circinella, Syncephalastrum, Chaetomium, Curvularia, Cladosporium, Helminthosporium, Montospora, Pullularia, Aspergillus, Penicillium, Cephalosporium, Trichoderma, Phoma, Fusarium.The internal fungi recovered from these varieties included species ofChaetomium, Cladosporium, Curvularia, Helminthosporium, Heterosporium, Hormodendron, Pullularia, Alternaria, Aspergillus, Blastomyces, Monilia, Penicillium, Fusarium, Phoma, Phomopsis. Varieties 4403B, 1060 and 503 were found to carry a large number of fungi. Variety Black spanish was found to be entirely free from any internal or external fungus. Varieties which were free from endophytic fungi but possess external fungi only were Kaoling 301, African variety 901 and Shallus 475. Three fungi viz.,Pullularia, Heterosporium, Monilia have been recovered from theSorghum seeds for the first time.     

AM真菌影响入侵植物黄顶菊与本土物种狗尾草竞争生长的机理研究

该研究以入侵植物黄顶菊[Flaveria bidentis(L.)Kunt]和本土伴生植物狗尾草为材料,通过筛选出黄顶菊单一优势群落AM真菌,于温室盆栽条件下,采用2物种单播、混播以及接种AM真菌和不接种共6个处理,分析AM真菌对黄顶菊和狗尾草的根系侵染率、相对竞争强度、植株氮磷钾光合利用率、以及丙二醛含量和保护酶活性的影响,探讨AM真菌对黄顶菊与狗尾草竞争生长的机理。结果显示:(1)黄顶菊根际土壤AM真菌共包括4属10种,其中优势种为Glomus constrictum、Glomus perpusillum、Glomus reticulatum;盆栽接种AM真菌后,黄顶菊的根系侵染率显著高于本土伴生植物狗尾草,但接种AM真菌后黄顶菊相对竞争强度显著降低了29.57%,却对狗尾草相对竞争强度无显著影响。(2)接种AM真菌使黄顶菊植株光合氮、磷、钾利用率显著升高,但对伴生植物狗尾草的光合氮、磷、钾利用率均无显著影响。(3)接种AM真菌对黄顶菊植株POD和CAT活性以及MDA含量无显著影响,但显著增加了SOD和APX活性,而伴对生植物狗尾草的POD、CAT和APX活性均显著降低,MDA含量显著提高。研究表明,AM真菌对黄顶菊和狗尾草具有不同的选择性,AM真菌的定植促进了黄顶菊的竞争生长,增加了植株N、P含量、光合养分利用率以及抗氧化酶活性;但显著降低了本土伴生植物狗尾草的N、P吸收以及抗氧化酶活性。因此,AM真菌在竞争生长中对黄顶菊产生了偏利反馈,有助于黄顶菊的入侵。     

Zoosporic marine fungi from the Pacific Northwest (U.S.A.)

Summary An investigation of the zoosporic fungi in the vicinity of the Friday Harbor Laboratory, San Juan Is., Washington, revealed the presence of great numbers of fungi. With one exception (Olpidium sp.) these were all biflagellate organisms. Predominating were species (11) of Thraustochytriaceae which abounded in water, in association with seaweeds, intertidal sands, and particularly on the surface of bottom samples down to depths of 298 m. A twelfth species of this group has several peculiarities and needs further investigation. Of the algal parasites, one on Polysiphonia and Pterosiphonia is considered new and termed Eurychasma joycei n. sp.The assistance of Drs. R. E. Norris and G. J. Hollenberg in calling my attention to certain algal parasites is gratefully acknowledged. I am also indebted to my colleague Dr. H. C. Whisler, and to Dr. C. Anastasiou for assistance in photographic work.     

Conversion of Nicotine into Nornicotine and N-Methylmyosmine by Fungi

Several species of fungi were tested for their abilities to degrade (S)-nicotine, of which Pelliculariafilamentosa JTS-208, the pathogen of tobacco damping off disease, and Cunninghamella echinulata IFO-4444, a saprophyte, were found to be able to degrade nicotine. P. filamentosa JTS-208 accumulated nornicotine only in the nicotine medium. C. echinulata IFO-4444 accumulated nornicotine and N-methylmyosmine, the first fungal metabolite, and three unidentified compounds.     

Mycorrhiza and root-associated fungi in Spitsbergen

Summary Roots of 76 plant species collected in West Spitsbergen (Svalbard), in the middle-northern Arctic zone, were examined for mycorrhiza and root-associated fungi. Dryas octopetala, Pedicularis dasyantha and Salix polaris were ectomycorrhizal and Cassiope tetragona and Empetrum hermaphroditum ericoid mycorrhizal. Pedicularis dasyantha was only slightly infected. Structures resembling vesicular-arbuscular mycorrhizal (VAM) fungi were not found in the roots, and soil samples screened for VAM fungi contained only one spore. Root endophytic fungi commonly occurred in Spits-bergen, but only Olpidium brassicae, Pleospora herbarum, Papulaspora, Microdochium bolleyi and Rhizoctonia solani were identified with reasonable certainty. A sterile endophytic dark-septate fungus (DSF) was in 39.5% of the flowering-plant species examined, especially in the Brassicaceae, Caryophyllaceae, Saxifragaceae and Poaceae. DSF were categorized into four slightly overlapping groups. Sterile endophytic hyaline septate fungi were rare. In the literature it is suggested that at least some of the DSF species or the hyaline septate fungi are functionally mutualistic rather than saprophytic or pathogenic. The literature on ectomycorrhizal fungi and plants in Spitsbergen is reviewed, including about 50 species, mainly of the genera Cortinarius, Hebeloma, Inocybe, Laccaria, Lactarius and Russula. These are symbiotic with the above-mentioned ectomycorrhizal plants. Four further ectomycorrhizal plants (Betula nana, Salix spp.) are very rare in the area.     

Interspecific Interactions among Tropical and Subtropical Freshwater Fungi

Abstract Twenty-seven species of tropical and subtropical fungi isolated from freshwater were examined for evidence of interspecific interactions, which are important in determining the ecological roles of fungi. Evidence for interspecific interactions was examined by inoculating paired fungi 25 mm apart on the surface of agar plates. The antagonistic activities were different among different isolates and even between isolates of the same species, for example, Ophioceras dolichostomum isolated from different origins. Pseudohalonectria longirostrum and Kirschsteiniothelia elaterascus, which produced pigment in culture, were strongly inhibitory species. Several aquatic hyphomycetes seems to be less competitive and less likely to produce antagonistic substances. Competitive abilities were also influenced by the range of enzymes that a fungus produced. For example, Verticillium sp. and Diaporthe sp., which produced only one or two kinds of enzyme, were found to exhibit weak competitive abilities and were easily replaced. The results of competition experiments also showed that slow-extending fungi (e.g., Pseudohalonectria longirostrum and Kirschsteiniothelia elaterascus) were more competitive than early fast-extending fungi (e.g., Ophioceras dolichostomum and Nectria haematococca). Received: 13 October 1998; Accepted: 3 March 1999     

The Antimicrobial Efficiency of Root Oil Against Human Pathogenic Bacteria and Phytopathogenic Fungi

The in vitro antimierobial activity of root oil of C. orchioides were studied against human pathogenic bacteria and phytopathogenic fungi by comparing the results with standard microbial susceptibility testing biodises. The oil of C. orchioides in case of bacteria shows significant activity against Bacillus anthracis, B. subtilis, Salmonella pullorum, S. newport, and Staph. aureus. While in case of fungi root oil had excellent activity against Fusarium monili forme, F. solani, Asprgullus flavus and Cladosporium and shows significant activity against all other tested fungi.     

Enzymes Associated with Defence against Toxic Oxygen Species in PCNB-Tolerant and Sensitive Soil Fungi

The specific activities of enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPOX) and glutathione reductase (GR), which are involved in protection against toxic species of oxygen, were determined in mycelia extracts of pentachloronitrobenzene (PCNB)-tolerant and susceptible soil fungi. The organisms assayed were the highly PCNB-sensitive Rhizoctonia solani and Rhizopus arrhizus; Sclerotium rolfsii and Trichoderma harzianum, which are moderately susceptible to PCNB, and the fungicide-tolerant Fusarium oxysporum f. sp. melonis and Pythium aphanidermatum. No GPOX activity was detected in the six examined fungi. Significant differences in the specific activities of the other enzyme systems among the fungi were evident. Remarkably low levels of CAT activities were measured in R. solani. Except for T. harzianum, no meaningful differences regarding SOD, CAT and GR activities with age of the fungi cultures were observed. The electrophoretic patterns of SOD and CAT displayed dissimilarities among the fungi under study. P. aphanidermatum is more polymorphic with respect to both SOD and CAT enzyme systems as compared to the other fungi. The SOD of F. oxysporum f. sp. melonis, R. arrhizus and T. harzianum is a cuprozinc enzyme, while the mangano-SOD species was detected in S. rolfsii, R. solani and T. harzianum.     

Selective Degradation of Wood Components by White-Rot Fungi

In order to find naturally occurring white-rot fungi which preferentially degrade lignin. 25 different species of such fungi were cultivated on pine wood blocks and on kraft lignin agar plates with and without cellulose. Due to differences in phenol oxidase reactions on the kraft lignin agar plates, the 25 fungi could be divided into two groups, 1 and 2, which also differed in other properties. The three Group I fungi Sporotrichum pulverulentum, Phanerochaete sp. L1 and Polyporus dichrous produced high levels of endo-l,4-β-glucanase and cellobiose:quinone oxidoreductase in shaking cellulose flasks and a low level of phenol oxidase in standing wood meal flasks, The four fungi Merulius tremellosus, Phlebia radiata, Pycuoporus cinnabarinus and Pleurotus ostreatus from Group 2, on the other hand, produced low levels of endo-1,4-β-glucanase and cellobiose:.quinone oxidoreductase in the cellulose. flasks and a high level of phenol oxidase in the wood meal flasks. Analyses of pine wood blocks degraded by the above-mentioned fungi in the presence of either malt extract, asparagine or NH₄H₂PO₄ revealed that malt extract gave good lignin degradation. In the presence of this nutrient source. P. cinnabarinus, at 3.4% weight loss, even degraded 12.5% lignin without loss of cellulose or mannan. No common degradation pattern was, however, obtained using mall extract, asparagine or NH₄H₂PO₄, It is suggested that while-rot fungi, which preferentially degrade lignin, may be found among Group 2 fungi producing large amounts of phenol oxidases.     

The Occurrence of Fungi in the Recently Discovered Jarkowicka Cave in the Karkonosze Mts. (Poland)

Our study is one of the very few cases of speleomycological research in recently discovered caves. The aim of this research was to assess the population size of fungal colonies and their species composition in the Jarkowicka cave, discovered in 2012. The air samples were taken from one location outside the cave and from two locations inside of it. Mycological evaluation of the rocks inside the cave was performed usingswab sampling procedure. In the Jarkowicka cave we found 22 species of fungi, including 13 isolated from air at the entrance and from the walls, and 8 species from air inside the cave. Cladosporium spp. were the fungi most frequently isolated from internal atmosphere of the Jarkowicka cave, and from the external air. On the other hand, the fungi most frequently isolated from the rocks were Mucor spp. We found several species not yet described as cave inhabitants: Hypocrea pachybasioides, Cladosporium uredinicola, and Embellisia abundans. Our study may provide a basis for comparison to other similar studies conducted in frequently visited caves by tourists.     

POLYPHASIC STUDY OF ANTARCTIC CYANOBACTERIAL STRAINS1

We isolated 59 strains of cyanobacteria from the benthic microbial mats of 23 Antarctic lakes, from five locations in two regions, in order to characterize their morphological and genotypic diversity. On the basis of their morphology, the cyanobacteria were assigned to 12 species that included four Antarctic endemic taxa. Sequences of the ribosomal RNA gene were determined for 56 strains. In general, the strains closely related at the 16S rRNA gene level belonged to the same morphospecies. Nevertheless, divergences were observed concerning the diversity in terms of species richness, novelty, and geographical distribution. For the 56 strains, 21 operational taxonomic units (OTUs, defined as groups of partial 16S rRNA gene sequences with more than 97.5% similarity) were found, including nine novel and three exclusively Antarctic OTUs. Sequences of Petalonema cf. involvens and Chondrocystis sp. were determined for the first time. The internally transcribed spacer (ITS) between the 16S and the 23S rRNA genes was sequenced for 33 strains, and similar groupings were observed with the 16S rRNA gene and the ITS, even when the strains were derived from different lakes and regions. In addition, 48 strains were screened for antimicrobial and cytotoxic activities, and 17 strains were bioactive against the gram‐positive Staphylococcus aureus, or the fungi Aspergillus fumigatus and Cryptococcus neoformans. The bioactivities were not in coincidence with the phylogenetic relationships, but rather were specific to certain strains.     

Changes in Aquatic Macrophytes after Liming Thrush Lake, Minnesota

Thrush Lake, Minnesota, was treated with limestone in 1988 to evaluate the efficacy of protective base addition against the loss of sport fisheries in a sensitive, mildly acidic lake. Prior to treatment, the lake was stressed (pH 6.46, ANC 64 μeq/L) but not severely degraded by acidic deposition and had a macrophyte community typical of lakes in northeastern Minnesota with low acid-neutralizing capacity (ANC). This paper describes the changes observed in aquatic plant communities during the 5 years after treatment, as pH and ANC slowly returned to pretreatment levels. Sphagnum platyphyllum, intolerant of non-acid conditions, was completely eliminated from the lake. The charo-phyte, Nitella, that originally shared dominance in the deep littoral zone with S. platyphyllum, decreased in importance during the first 2 years after treatment. Two vascular plants, Potamogeton pusillus and Najas flexilis, were first found in the lake the year after treatment and were abundant for 2 years after liming, probably in response to a combination of more neutral pH and reduced cover of Nitella. As the ANC and pH slowly returned to pretreatment conditions, Nitella again increased in coverage and depth range, with a concomitant decrease in P. pusillus and N. flexilis. The moss, S. platyphyllum, had not reinvaded the lake by 1993, 2 years after its dramatic decline.     

Fungi colonizing hair-baits from three coastal beaches of Mexico

The abundance of hair-bait colonizing fungi was investigated on the beaches of Caracoles, Mocambo, and lcacos, located on the coasts of the Caribbean Sea, Gulf of Mexico and Pacific Ocean, respectively. On each beach a sample of sandy soil was collected. The samples were analyzed by two selective isolation methods for keratinophilic fungi resulting in a total of 544 occurrences. A total of 17 species was found, of which 4 were ascomycetes and 13 hyphomycetes.Gymnascella dankaliensis andAspergillus terreus were the most abundant.Arthroderma curreyi andChrysosporium tropicum were found in low percentages in this survey. From the three beaches sampled, Icacos beach, on the Pacific Ocean coast had the highest number of isolated species.     

Fungi pathogenic to ryegrass seedlings

Summary Fungi borne on or in ryegrass (Lolium spp.) seeds or invading ryegrass seedlings grown on field soils were isolated and identified. Selected isolates were tested to determine their pathogenicity to ryegrass seedlings. Seed-borne fungi were generally weakly virulent or non-pathogenic to ryegrass seedlings. Pathogenic seed-borne fungi includedChaetomium globosum Kunze: Fr.,Curvularia trifolii (Kauffm.) Boedijn, and species ofPenicillium Link andAspergillus Mich. ex Link. Species of fungi isolated from seedlings grown on field soils de pended on soil and temperature. Soil-borne fungi pathogenic to seedlings includedFusarium avenaceum (Fr.) Sacc.,F. culmorum (W. G. Smith) Sacc.,F. equiseti (Corda) Sacc.,F. oxysporum Schlecht.: Fr.,F. solani (Mart.) Sacc.,Pythium afertile Kanouse and Humphrey,P. debaryanum auct. non Hesse,P. irregulare Buisman,P. ultimum Trow, a sphaerosporangiatePythium sp.,Chaetomium globosum, Thanatephorus cucumeris (Frank) Donk,Trichoderma koningii Oudem., and aPhomopsis sp. Individual isolates of fungi differed in virulence to ryegrass seedlings, and ryegrass cultivars differed in susceptibility to seedling pathogens.     

The Susceptibility of Different Species and Stages of Ticks to Entomopathogenic Fungi

Boophilus annulatus, Hyalomma excavatum and Rhipicephalus sanguineus ticks were shown to be susceptible to different entomopathogenic fungi under laboratory conditions. Comparative results of bioassays using five different fungal species showed that some strains of Metarhizium anisopliae are highly pathogenic against various tick stages tested. In contrast to their activity against insects, fungi also affected tick eggs. All tested tick stages including those feeding on a host were found to be susceptible to these fungi, except for adult H. excavatum ticks, which were relatively resistant. This revised version was published online in July 2006 with corrections to the Cover Date.