Detection of Cryptococcus neoformans var. grubii in honeybee (Apis mellifera) colonies. Nachweis von Cryptococcus neoformans var. grubii in Stocken der Honigbiene (Apis mellifera)

The plant flora has an important role in the ecology of Cryptococcus neoformans. It is estimated that the environmental spreading and contamination of human beings with this yeast occurs via contaminated particles of plants. Cultivation of canopy parts of plants in selective media is the most widely used isolation method of this yeast. Cryptococcus neoformans var. grubii was isolated from honeybee colonies in Eucalyptus forests but was not isolated from the places where this flora did not exist. Our results indicate that the occurrence of C. neoformans in honeybee colonies during the flowering season of Eucalyptus spp. trees can be an important bioindicator for environmental yeast presence. The screening of honeybee colonies is a practical and a rapid method for the monitoring of the C. neoformans presence in flowering plants.

The First Isolation of Cryptococcus neoformans from Eucalyptus Trees in South Aegean and Mediterranean Regions of Anatolia in Turkey despite Taurus Mountains alkalinity

Eucalyptus trees are widespread in subtropical parts of Turkey that have alkaline environments due to the soil structure of Taurus Mountains. In this study, the existence of Cryptococcus neoformans in eucalyptus trees in the South Aegean and Mediterranean Regions of Anatolia, Turkey, was screened between March 1998 and September 2002. Only one strain of Cryptococcus neoformans var. grubii (Serotype A) was isolated from 1175 eucalyptus samples including debris and flowers in culture by Guizotia abyssinica agar. The environmental niche of the isolate was Eucalyptus camaldulensis Dehn in the Gokova Region, in the western part of the Taurus Mountains. In this study, the existence of Cryptococcus neoformans was shown in the eucalyptus flora of Turkey despite the alkaline soil condition.

Cryptococcus neoformans varieties from material under the canopies of eucalyptus trees and pigeon dropping samples from four major cities in Jordan

To our best knowledge, any study related to the ecological distribution of Cryptococcus neoformans in Jordan does not exist in the medical literature. In order to determine the environmental occurrence of both varieties of Cryptococcus neoformans in Jordan, pigeon droppings and material under the canopies of eucalyptus trees were collected from four major cities of this country. For the isolation of Cryptococcus neoformans variety gattii from environmental sources, 500 samples of the mixed soil debris, including tree materials, under the eucalyptus trees from cities of Amman, Irbid, Jerash, and Ajlun were collected. Also, 509 samples of pigeon droppings were collected from the same cities for the isolation of Cryptococcus neoformans variety neoformans. After inoculating the samples onto modified Staib agar medium in Petri dishes, a total of 336 melanoid yeast colonies were picked up during screening process. At the end of serial mycological studies, none of these isolates was identified as Cryptococcus neoformans, but all were Cryptococcus species other than C. neoformans. For determining the exact status, more extensive environmental studies need to be done in the future.

Systematic reappraisal of Coniella and Pilidiella, with specific reference to species occurring on Eucalyptus and Vitis in South Africa

The genus Pilidiella, including its teleomorphs in Schizoparme, has a cosmopolitan distribution and is associated with disease symptoms on many plants. In the past, conidial pigmentation has been used as a character to separate Pilidiella (hyaline to pale brown conidia) from Coniella (dark brown conidia). In recent years, however, the two genera have been regarded as synonymous, the older name Coniella having priority. To address the generic question, sequences of the internal transcribed spacer region (ITS1, ITS2), 5.8S gene, large subunit (LSU) and elongation factor 1-alpha gene (EF 1-alpha) were analysed to compare the type species of Pilidiella and Coniella. All three gene regions supported the separation of Coniella from Pilidiella, with the majority of taxa residing in Pilidiella. Pilidiella is characterised by having species with hyaline to pale brown conidia (avg. length:width > 1.5), in contrast to the dark brown conidia of Coniella (avg. length:width < or = 1.5). Pilidiella diplodiella, which is a pathogen associated with white rot of grapevines, was shown to be an older name for C. petrakii. To delineate species in the P. diplodiella species complex, isolates were also compared based on histone (H3) gene sequences. Analyses derived from these sequence data separated P. diplodiella from a newly described species, P. diplodiopsis. The new species P. eucalyptorum sp. nov. is proposed for isolates formerly treated as C. fragariae and associated with leaf spots of Eucalyptus spp. This species clustered basal to Pilidiella, and may represent yet a third genus within this complex. Pilidiella destruens sp. nov. is newly described as anamorph of Schizoparme destruens, which is associated with twig dieback of Eucalyptus spp. in Hawaii. A key based on morphological characteristics is provided to separate the taxa treated in this study.

Investigation in Central Italy of the possible association between Cryptococcus neoformans var. Gattii and Eucalyptus camaldulensis

The authors present a worldwide review of isolations of Cryptococcus neoformans, var. neoformans and C. neoformans var. gattii from animals and vegetation, referring in particular to the already well-known association of the former variety with Eucalyptus camaldulensis. They then review the Italian situation relative to this association and their studies carried out in Central Italy: in Latina (Lazio), Pisa, Viareggio and Lake Massaciuccoli (Tuscany). From the 256 E. camaldulensis trees examined C. neoformans var. gattii was not isolated. An E. camaldulensis tree situated in the nature reserve on Lake Massaciuccoli proved to be positive for C. neoformans var. neoformans. This variety was isolated from the leaves, flowers, bark and the debris at the foot of the tree, suggesting that it had colonized the entire tree and that it was capable of developing not only on its usual habitat (bird guano, soil rich with guano) but also on Eucalyptus trees. The identity of the isolates was confirmed by their genomic profiles obtained by random amplification polymorphic DNA (RAPD) with the primer (GACA)4. The presence of a single genotype indicates a sole source of contamination, perhaps brought by a bird coming from a contaminated environment.

Hypaphorine, an indole-3-acetic acid antagonist delivered by the ectomycorrhizal fungus Pisolithus tinctorius, induces reorganisation of actin and the microtubule cytoskeleton in Eucalyptus globulus ssp bicostata root hairs

Hypaphorine, an indole alkaloid from the ectomycorrhizal fungus Pisolithus tinctorius Coker & Couch., counteracts indole-3-acetic acid (IAA) activity and controls the rate of root hair elongation in Eucalyptus globulus ssp. bicostata. The present investigation shows that hypaphorine changes cytoskeletal organisation in elongating root hairs of the host. The actin cytoskeleton was investigated by two different fixation and labelling procedures, which gave similar results. In control root hairs, actin organisation was characterised by (i) an actin cap at the very tip region, (ii) a subapical region with reduced labelling and containing fine actin filaments, and (iii) axial bundles of actin filaments running from the subapical part to the base of the root hair. In the hypaphorine-treated root hairs no actin cap was distinguished. The fine actin filaments occurring in the subapical region were replaced by a few thick actin filament bundles that extended from the subapical region toward the root hair tip. In the hypaphorine-treated hairs the total number of actin filament bundles along most of the root hair length was significantly reduced, presumably due to aggregation of pre-existing actin filaments. The first signs of alteration to the cytoskeleton could be detected as soon as 15 min after hypaphorine treatment. In hypaphorine-treated, but not in control root hairs, a patch of aggregated microtubules regularly occurred at a distance of approximately 10 microm from the tip, possibly as a consequence of changes induced by hypaphorine in the actin cytoskeleton. The hypaphorine-induced aggregations in the actin and microtubule cytoskeletons could stabilise the structure of cytoskeletal elements, which in turn could hinder the vesicle delivery at the tip necessary for elongation. Such cytoskeletal alterations may be a consequence of the antagonism between IAA and hypaphorine. The latter view was supported by restoration of the actin cytoskeleton in hypaphorine-treated root hairs by IAA application.

Resistance to rust ( Puccinia psidii Winter) in eucalyptus: mode of inheritance and mapping of a major gene with RAPD markers

Rust is one of the most-damaging eucalypt diseases in Brazil and is considered a potential threat to eucalypt plantations worldwide. To determine the mode of inheritance of resistance in the Eucalyptus grandis- Puccinia psidii pathosystem, ten full-sib families, generated from crosses between susceptible and resistant trees, were inoculated with a single-pustule isolate of the pathogen and rust severity was scored. The observed segregation ratios in segregating families suggested major gene control of rust resistance, although clearly incomplete penetrance, variable expressivity and minor genes are also involved in the global rust-resistance response. To identify markers linked to the resistance locus, screening of RAPD polymorphisms was conducted using bulked segregant analysis in a large full-sib family. A linkage group was built around the Ppr1 gene ( P. psidii resistance gene 1) encompassing six RAPD markers, with a genetic window spanning 5 cM with the two most-closely linked flanking markers. Besides these two flanking markers, RAPD marker AT9/917 co-segregated with Ppr1 without a single recombinant in 994 meioses. This tightly linked marker should prove useful for marker-assisted introgression and will provide an initial lead for a positional cloning effort of this resistance allele. This is the first report of a disease resistance gene identified in Eucalyptus, and one of the few examples of the involvement of a major gene in a non-coevolved pathosystem.

Distribution of Amanita spp. genotypes under eastern Australian sclerophyll vegetation

Basidiomes of Amanita alboverrucosa, A. ochrophylla, and A. pyramidifera were collected from native mixed sclerophyll forest sites and of A. conicoverrucosa and A. punctata from planted stands of Eucalyptus maculata in New South Wales, Australia. DNA was extracted from stipe tissue and subjected to inter-simple sequence repeat (ISSR) PCR analysis conducted using the primers (GTG)5 and (GACA)4 in order to determine genotype distribution at each site. Two to nine genotypes of one of the species were identified at each field site. Genotypes of A. ochrophylla, A. conicoverrucosa and A. punctata were spread over areas of ca 10-60 m diam, suggesting vegetative spread via large below-ground mycelial genets. In contrast, genotypes of A. alboverrucosa were more spatially restricted, suggesting recent establishment via basidiospores and more limited below-ground vegetative spread. Two groups of A. pyramidifera basidiomes that were separated by ca 600 m were found to be of the same genotype. While this might reflect long distance spread of below-ground mycelium in this taxon, the proximity of the basidiomes to a roadway makes movement of vegetative basidiome tissue via vehicular activity and subsequent establishment equally plausible.

Molecular typing of clinical and environmental Cryptococcus neoformans isolates in the Brazilian state Rio Grande do Sul

In Brazil, 4.5% of the AIDS-related opportunistic infections are caused by Cryptococcus neoformans. This pathogen is a ubiquitous environmental basidiomycetous encapsulated yeast, commonly found in soil and avian excreta. The present study investigates further the population structure of clinical and environmental C. neoformans isolates from south Brazil. One hundred five clinical and 19 environmental (pigeon excreta and Eucalyptus spp.) isolates from the Brazilian state Rio Grande do Sul were characterized based on morphological, biochemical, molecular and serological data. The majority of the clinical and environmental isolates analyzed belonged to C. neoformans var. grubii serotype A (89.5 and 52.6%, respectively), were mating type alpha (98.1 and 94.7%, respectively) and were phospholipase-positive (94.3 and 73.7%, respectively). PCR-fingerprinting with the microsatellite-specific primer M13 and the minisatellite-specific primer (GACA)(4) grouped the majority of the isolates into the molecular type VNI (89.5 of the clinical and 52.6% of the environmental isolates). Our results add considerable new information to the few available data on ecology, molecular biology and epidemiology of C. neoformans in the southern region of Brazil.

Novel detection of formylated phloroglucinol compounds (FPCs) in the wound wood of Eucalyptus globulus and E. nitens

This study characterized the chemical responses of Eucalyptus globulus and Eucalyptus nitens to artificial inoculation with a basidiomycete decay fungus. Nine-year-old trees responded to mechanical wounding or inoculation with the decay fungus by producing new wound wood characterized by the presence of dark extractives 17 months after wounding. Analysis of crude wound wood extracts by HPLC coupled to negative ion electrospray mass spectrometry revealed the presence of a complex mixture of many unidentified formylated phlorglucinol compounds (FPCs), in addition to a diverse range of other polyphenolic compounds (hydrolyzable tannins, proanthocyanidins, flavanone glycoside, stilbene glycosides). Prior to this study, FPCs have only been reported from leaves and buds of Eucalyptus spp. Unequivocal evidence for the presence of macrocarpal A and B, and sideroxylonal A and B in the crude extracts was obtained, as well as evidence for a wide range of as yet unreported FPCs. Subsequent preliminary in vitro fungal and bacterial bioassays did not support an antimicrobial role for FPCs in host-pathogen interactions in eucalypts.

Novel detection of formylated phloroglucinol compounds (FPCs) in the wound wood of Eucalyptus globulus and E. nitens

This study characterized the chemical responses of Eucalyptus globulus and Eucalyptus nitens to artificial inoculation with a basidiomycete decay fungus. Nine-year-old trees responded to mechanical wounding or inoculation with the decay fungus by producing new wound wood characterized by the presence of dark extractives 17 months after wounding. Analysis of crude wound wood extracts by HPLC coupled to negative ion electrospray mass spectrometry revealed the presence of a complex mixture of many unidentified formylated phlorglucinol compounds (FPCs), in addition to a diverse range of other polyphenolic compounds (hydrolyzable tannins, proanthocyanidins, flavanone glycoside, stilbene glycosides). Prior to this study, FPCs have only been reported from leaves and buds of Eucalyptus spp. Unequivocal evidence for the presence of macrocarpal A and B, and sideroxylonal A and B in the crude extracts was obtained, as well as evidence for a wide range of as yet unreported FPCs. Subsequent preliminary in vitro fungal and bacterial bioassays did not support an antimicrobial role for FPCs in host-pathogen interactions in eucalypts.

A PCR/RFLP technique to characterize fungal species in Eucalyptus grandis Hill ex. Maiden ectomycorrhizas

With the increasing awareness of the significance of mycorrhizas, research is focusing on studies to elucidate the contribution of the symbiosis to ecosystem dynamics. In this sense, molecular biology has acquired great significance. PCR/RFLP techniques were adapted to characterize ectomycorrhizal fungi associated with Eucalyptus grandis. The ITS region of the fungal rDNA from pure cultures and from of mycorrhizas synthesized in vitro was amplified. Primers NSA3/NLC2 were used followed by a nested reaction with primers ITS1F/NLB3. Amplicons were then digested with the enzymes MboI, HinfI and TaqI. Amplification resulted in a 1,000-bp fragment for basidiomycetes and a 1,500 bp fragment for Cenococcum geophillum (an ascomycete). There was no amplification of the plant DNA. The enzymes MboI and HinfI were more effective than TaqI, resulting in patterns of two to five fragments allowing the identification of the isolates both in culture and in mycorrhizas. HinfI allowed greater differentiation among the isolates and a higher number of polymorphisms. Restriction with TaqI resulted in too many fragments. Amplification efficiency for the fungal DNA was 64% in culture and 87% in mycorrhizas. The modified methodology represents a valuable tool to complement traditional approaches in ecosystem studies.

Morphological, cultural and pathogenic characteristics of Coniothyrium zuluense isolates from different plantation regions in South Africa

Coniothyrium canker caused by Coniothyrium zuluense, is a serious stem canker disease of Eucalyptus species in sub-tropical regions of South Africa. This disease is typified by necrotic bark lesions that coalesce to form large kino-impregnated cankers along the stems of trees. The strategy currently used to manage Coniothyrium canker in plantations is to deploy Eucalyptus species or clones that are resistant to the disease. Considerable success has already been achieved in this regard, but the long-term durability of resistance is of concern. Thus, forest managers are interested in the genetic diversity of the pathogen and its potential to overcome disease resistance in planting stock. In this study, 344 isolates of C. zuluense from different plantation regions in South Africa were compared on the basis of colony colour, conidial morphology, growth characteristics on agar and pathogenicity to a susceptible E. grandis clone. Conidia of all C. zuluense isolates measured were similar in size and shape. The fungus is slow growing in culture, which is indicative of its apparent biotrophic habit, with optimum growth observed at 30 degrees C. Isolates of C. zuluense displayed considerable variation in colony colour and pathogenicity in inoculation trials. Variation in morphology and pathogenicity amongst isolates suggests that C. zuluense has been present in South Africa for an extended period of time, or that it is changing rapidly due to strong directional selection pressures.

Mycosphaerella species associated with Eucalyptus in south-western Australia: new species, new records and a key

Mycosphaerella ambiphylla sp. nov. (anamorph: Phaeophleospora) and Mycosphaerella aurantia sp. nov., are described from diseased Eucalyptus globulus leaves. In addition, a new fungal record in Australia, M. mexicana, and two new records for Western Australia, M. gregaria and M. parva, are discussed. A key is provided to Mycosphaerella species on E. globulus in Western Australia.

Extracellular polysaccharides of Erwinia futululu, a bacterium associated with a fungal canker disease of Eucalyptus spp

Extracellular polysaccharides (EPSs) produced by an Erwinia spp. associated with a fungal canker disease of Eucalyptus were fractionated into two polysaccharides, one that was identified with that produced by Erwinia stewartii. The other has a similar structure, but with one terminal Glc residue replaced by pyruvic acid to give 4,6-O-[(R)-1-carboxyethylidene)-Galp. Their structures were determined using a combination of chemical and physical techniques including methylation analysis, periodate oxidation, low-pressure gel filtration and anion-exchange chromatographies, high-pH anion-exchange chromatography, mass spectrometry and 1D and 2D 1H NMR spectroscopy. The new polysaccharides, identified as EPS Futululu FF-1 and FF-2, have the following structures:The molecular weights of the polysaccharides range from 1.3-2.1x10(6) and their hydrodynamic properties are those of polydisperse, polyanionic biopolymers with pseudoplastic, non-thixotropic flow characteristics in aqueous solutions.

Are Sebacinaceae common and widespread ectomycorrhizal associates of Eucalyptus species in Australian forests?

A molecular survey of basidiomycete ectomycorrhizal fungi colonising root tips at a site in Eucalyptus marginata (jarrah) forest revealed the presence of many fungal species which could not be identified from a database of ITS-PCR-RFLP profiles from morphologically identified species. Three of these unidentified taxa were among the six most frequently encountered profiles. Phylogenetic analyses of ITS and nuclear LSU sequences revealed a close relationship among the three fungi and that they belong to the family Sebacinaceae (sensu Weiss and Oberwinkler 2001). The possibility that DNA of non-ectomycorrhizal rhizosphere or endophytic fungi had been amplified selectively by the basidiomycete-specific primers was tested by amplification with fungal-specific primers. A single PCR fragment was amplified in all but two of the 24 samples tested and digestion with two restriction enzymes produced RFLP profiles which matched those from the Sebacinoid sequence. We conclude, therefore, that at least three species of Sebacinaceae are common ectomycorrhizal associates of E. marginata.

Cryptococcus neoformans in the koala (Phascolarctos cinereus): colonization by C n. var. gattii and investigation of environmental sources

This study is the one in a series looking at the relationship among Cryptococcus neoformans var. gattii, koalas and the environment. The koala was used as a natural biological sampler in an attempt to understand the dynamics of C. neoformans var. gattii in Australian environments. Evidence of asymptomatic nasal and skin colonization for extended periods by large numbers of C. n. var. gattii was obtained and geographical factors assessed. The key finding was the ability of koalas to amplify numbers of C. n. var. gattii in certain environments. Koalas were not found to be obligatory for the survival of the organism in all environments. Geographical factors alone could not explain differing rates of nasal and skin colonization in koalas in different environments. A strong association between healthy koalas and C. n. var. gattii was confirmed and C n. var. gattii was isolated from novel sources, including the turpentine gum tree (Syncarpia glomulifera), tallowwood (Eucalyptus microcorys) and flooded gum (E. grandis). It seems likely that as yet undiscovered environmental sources of C. n. var. gattii exist in eastern Australia. Further investigation of host, environmental and organism factors integral to the hostpathogen relationship will assist an understanding of the progression from colonization to tissue invasion and cryptococcosis in all species.

Extracellular polysaccharides of a bacterium associated with a fungal canker disease of Eucalyptus sp

Extracellular polysaccharides (EPSs) produced by an Erwinia sp associated with a fungal canker disease of Eucalyptus were fractionated into one polysaccharide that was identified with that produced by Erwinia chrysanthemi strains SR260, Ech1, and Ech9, and the other distinctively different from any other EPS produced by E. chrysanthemi strains so far studied. Their structures were determined using a combination of chemical and physical techniques including methylation analysis, low pressure gel-filtration, and anion-exchange chromatographies, high-pH anion-exchange chromatography, mass spectrometry and 1D and 2D 1H NMR spectroscopy. The new polysaccharide, identified as EPS Teranera, has the following structure: [structure: see text] The molecular weights of the polysaccharides range from 3.2-6.2 x 10(5) and their hydrodynamic properties are those of polydisperse, polyanionic biopolymers with pseudoplastic, non-thixotropic flow characteristics in aqueous solutions.

Production of new unsaturated lipids during wood decay by ligninolytic basidiomycetes

Lipids were analyzed by gas chromatography-mass spectrometry for a 7-week in vitro decay of eucalypt wood by four ligninolytic basidiomycetes. The sound wood contained up to 75 mg of lipophilic compounds per 100 g of wood. Hydrolysis of sterol esters, which represented 38% of total wood lipids, occurred during the fungal decay. The initial increase of linoleic and other free unsaturated fatty acids paralleled the decrease of sterol esters. Moreover, new lipid compounds were found at advanced stages of wood decay that were identified from their mass spectra as unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid. These dicarboxylic acids were especially abundant in the wood treated with Ceriporiopsis subvermispora (up to 24 mg per 100 g of wood) but also were produced by Phlebia radiata, Pleurotus pulmonarius, and Bjerkandera adusta. We hypothesize that three main alkylitaconic acids (tetradecylitaconic, cis-7-hexadecenylitaconic, and hexadecylitaconic acids) are synthesized by fungi in condensation reactions involving palmitic, oleic, and stearic acids. We suggest that both wood unsaturated fatty acids (present in free form or released from esters during natural decay) and unsaturated metabolites synthesized by fungi could serve as a source for peroxidizable lipids in lignin degradation by white rot basidiomycetes.

Decaying wood in tree trunk hollows as a natural substrate for Cryptococcus neoformans and other yeast-like fungi of clinical interest

The occurrence of Cryptococcus neoformans var. neoformans and other yeast-like fungi of clinical interest in decaying wood inside tree trunk hollows, bark and other plant materials is reported. The var. neoformans was isolated from 3 of 45 (6.6%) wood and one of 390 Eucalyptus bark samples. Two of the positive wood samples came from a tree trunk hollow of Butea monosperma (Family: Papilionaceae) growing in Roshan Ara Garden, Old Delhi whereas the third was from a trunk hollow of Tamarindus indica (Family: Papilionaceae) growing outside of Talkatora Garden, New Delhi. The solitary positive Eucalyptus bark sample originated from Amritsar. The isolations of var. neoformans from decaying wood inside trunk hollows of B. monosperma and T indica constitute the first record of the natural occurrence of this pathogen in association with these trees. The observation reinforces the recent evidence for decaying wood inside trunk hollows of some trees to be a new natural habitat of the variety neoformans. Besides, in consonance with their essentially saprobic character, a number of other yeast-like fungi were sporadically isolated. This includes, Cryptoccus laurentii, Cryptococcus albidus, Candida lusitaniae, C. guilliermondii, C. krusei, C. tropicalis, C. zeylanoides, Trichosporon cutaneum, Rhodotorula mucilaginosa, R. glutinis, Geotrichum capitatum, G. klebahnii and Sporobolomyces salmonicolor. Cryptococcus neoformans var. gattii was not found in any of the 702 samples of plant materials, including the bark and detritus of Eucalyptus camaldulensis and E. tereticornis trees. A more extensive environmental survey, covering divergent climatic regions, is warranted to identify the natural reservoirs of var. gattii in India.

Environmental sampling for Cryptococcus neoformans var. gattii from the Blue Mountains National Park, Sydney, Australia

The environmental association of Cryptococcus neoformans var. gattii with decaying wood in tropical and subtropical regions of the world is well documented. In Australia, the yeast appears confined to certain species of Eucalyptus or very closely related tree species. In this study, we attempted to isolate C. n. var. gattii from different gum tree species in the Blue Mountains National Park. Out of 99 samples from 9 different tree species, only 3 yielded viable yeast colonies; 2 were from turpentine gums (Syncarpia glomulifera) and 1 was from a decayed stump of an unknown species. All of the colonized trees occurred in close proximity in urbanized areas of the Park, and all isolates shared identical DNA fingerprinting profiles. We suggest that domestic animal vectors may be responsible for the introduction and transmission of the yeast in this region, but that propagation and dispersal are very limited. This study indicates that C. n. var. gattii may occur on trees and in areas that were not previously expected to host it. However, the low incidence in the Blue Mountains National Park means this yeast is unlikely to pose any hazards to humans and animals living in or visiting this area.

Identification of a novel series of alkylitaconic acids in wood cultures of Ceriporiopsis subvermispora by gas chromatography/mass spectrometry

A novel series of long-chain unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid has been identified by gas chromatography/mass spectrometry during in vitro decay of eucalypt wood by the white-rot basidiomycete Ceriporiopsis subvermispora. The major compounds were identified as tetradecyl-, 7-hexadecenyl- and hexadecylitaconic acids by their mass fragmentation patterns. Other members of the same compound series, identified as dodecanyl-, tridecanyl-, tetradecenyl-, pentadecanyl-, octadecenyl- and octadecanylitaconic acids, were present in very minor amounts or traces. Whereas hexadecenylitaconic acid has already been reported in cultures of C. subvermispora, to our knowledge this is the first report of the presence of the other alkylitaconic acids in fungal cultures. These new alkylitaconic-type metabolites may constitute a source for peroxidizable lipids involved in lignin degradation during wood decay by C. subvermispora and other white-rot basidiomycetes.

Time course of fungal removal of lipophilic extractives from Eucalyptus globulus wood

Free and esterified sitosterol, the main lipophilic constituents of eucalypt wood extractives, have been associated with the formation of pitch deposits during manufacturing of environmentally-sound paper pulp from Eucalyptus globulus wood. These, and other lipophilic compounds, were analyzed by gas chromatography-mass spectrometry in the course of wood treatments (up to 7 weeks) with four extractive-degrading fungi in order to optimize biotechnological control of pitch deposition in eucalypt pulp (with moderate loss of wood weight). In contrast to commercialized fungi used in pitch control, which are not able to degrade sitosterol, the fungi investigated in this paper produced a rapid decline of both free and esterified sterols in wood. The degradation rate of steroid hydrocarbons and squalene was moderate, and the amount of steroid ketones (probably formed during oxidative degradation of steroids) and triglycerides increased at different stages of wood treatment. Up to 95% removal of total steroids (including free and esterified sterols, steroid ketones and steroid hydrocarbons) by fungi was obtained at the end of wood treatment under the solid-state fermentation conditions used. The most promising results from the point of view of industrial applicability, however, were obtained after 1-2 weeks of treatment with either Phlebia radiata or Poria subvermispora, which enabled 70% steroid removal with a moderate wood weight loss of 1-4%.

In situ localization of endogenous cytokinins during shooty tumor development on Eucalyptus globulus Labill

Our previous results demonstrated that endogenous cytokinins are involved in the shooty potential of tumors initiated on Eucalyptus globulus plantlets inoculated with Agrobacterium tumefaciens strain 82.139 [A. Azmi et al. (1997a) Plant Sci 127: 81-90]. In order to investigate whether or not these hormones are distributed homogeneously in the tumors prior to the onset of bud regeneration, decapitated hypocotyls were inoculated with the strain C58pMP90/T139 GUS-INT harboring the wild transferred DNA (T-DNA) of strain 82.139 tagged with the beta-glucuronidase (gus)-reporter gene. In situ immunolocalization of zeatin, dihydrozeatin and isopentenyladenine was performed in the developing tumors and combined with the histo-enzymological beta-glucuronidase assay. It was found that the expression of the T-DNA was restricted to only some small areas located deeply in the tumors. These sites were also provided with a high cytokinin signal while the untransformed parts of the tumors displayed a weaker signal, except in the early differentiating tracheary elements. The regenerated buds were untransformed and originated from superficial parts of the tumors provided with a moderate signal for cytokinins. The method of colocalization of both cytokinins and gus expression developed here might be helpful for further studies concerning the role of these hormones in controlling gene expression at cell and tissue levels.

Identification of symbiosis-regulated genes in Eucalyptus globulus-Pisolithus tinctorius ectomycorrhiza by differential hybridization of arrayed cDNAs

Ectomycorrhiza development alters gene expression in the fungal and plant symbionts. The identification of a large number of genes expressed exclusively or predominantly in the symbiosis will contribute greatly to the understanding of the development of the ectomycorrhizal symbiosis. We have constructed a cDNA library of 4-day-old Eucalyptus globulus-Pisolithus tinctorius ectomycorrhiza and sequenced 850 cDNAs cloned randomly or obtained through suppression subtractive hybridization (SSH). Based on the absence of a database match, 43% of the ectomycorrhiza ESTs are coding for novel genes. At the developmental stage analysed (fungal sheath formation), the majority of the identified sequences represented 'housekeeping' proteins, i.e. proteins involved in gene/protein expression, cell-wall proteins, metabolic enzymes, and components of signalling systems. We screened arrayed cDNAs to identify symbiosis-regulated genes by using differential hybridization. Comparisons of signals from free-living partners and symbiotic tissues revealed significant differences in expression levels (differential expression ratio >2.5) for 17% of the genes analysed. No ectomycorrhiza-specific gene was detected. The results successfully demonstrate the use of the cDNA array and SSH systems as general approaches for dissecting symbiosis development, and provide the first global picture of the cellular functions operating in ectomycorrhiza.

Identification of symbiosis-regulated genes in Eucalyptus globulus-Pisolithus tinctorius ectomycorrhiza by differential hybridization of arrayed cDNAs

Ectomycorrhiza development alters gene expression in the fungal and plant symbionts. The identification of a large number of genes expressed exclusively or predominantly in the symbiosis will contribute greatly to the understanding of the development of the ectomycorrhizal symbiosis. We have constructed a cDNA library of 4-day-old Eucalyptus globulus-Pisolithus tinctorius ectomycorrhiza and sequenced 850 cDNAs cloned randomly or obtained through suppression subtractive hybridization (SSH). Based on the absence of a database match, 43% of the ectomycorrhiza ESTs are coding for novel genes. At the developmental stage analysed (fungal sheath formation), the majority of the identified sequences represented 'housekeeping' proteins, i.e. proteins involved in gene/protein expression, cell-wall proteins, metabolic enzymes, and components of signalling systems. We screened arrayed cDNAs to identify symbiosis-regulated genes by using differential hybridization. Comparisons of signals from free-living partners and symbiotic tissues revealed significant differences in expression levels (differential expression ratio >2.5) for 17% of the genes analysed. No ectomycorrhiza-specific gene was detected. The results successfully demonstrate the use of the cDNA array and SSH systems as general approaches for dissecting symbiosis development, and provide the first global picture of the cellular functions operating in ectomycorrhiza.

Enrichment and isolation of non-specific aromatic degraders from unique uncontaminated (plant and faecal material) sources and contaminated soils

Microbial analysis of contaminated soil and uncontaminated plant and faecal material resulted in the enrichment of a number of microbial communities capable of utilizing a range of environmental pollutants. Growth was observed on polycyclic aromatic hydrocarbons, polychlorinated biphenyls, heterocyclic aromatic compounds and organochlorine pesticides. However, none of the communities could grow on pentachlorophenol. Pure cultures were isolated from microbial communities using phenanthrene and pyrene as the sole carbon and energy source. Isolates were also obtained using DDT, DOH, DBH and PCPA when peptone was supplemented to the medium. Strain AJR39,504, isolated using DDT and peptone, could not be positively identified on the basis of substrate utilization tests. However, it most closely resembled Stenotrophomonas maltophilia (0.424 similarity) using the Microlog 3 database software. Isolate AJR39, 504 could also grow on polycyclic aromatic hydrocarbons, chlorinated- and nitro-aromatic compounds. In addition, the degradation of DDT (100 mg l(-1)) by isolate AJR39,504 resulted in a 35% decrease in DDT concentration after 28 days with a concomitant increase in DDD concentration.

Environmental isolation of Cryptococcus neoformans var. gattii and C. neoformans var. neoformans in the city of São Paulo, Brazil

In order to determine the environmental occurrence of both varieties of Cryptococcus neoformans in the city of São Paulo, pigeon droppings and vegetable material from trees of the genus Eucalyptus were collected at typically crowded places. A total of 38 sites downtown where large heaps of pigeon droppings could be found were selected for sampling. Pigeon droppings from 10 (26.3%) of these sites were positive for C. neoformans var. neoformans in at least one sample. Twelve eucalyptus woods located within four municipal parks were also surveyed; vegetable material from Eucalyptus spp. trees were collected monthly over a 2-year period. C. neoformans var. gattii was recovered from a wood in Ibirapuera Park during the same season on two different occasions (November 1996 and November 1997); this park contained specimens of Eucalyptus camaldulensis, a natural habitat of C. n. var. gattii. C. n. var. neoformans was detected in a wood in Ibirapuera Park and Aclimação Park. The results show that both C. n. var. neoformans and C. n. var. gattii are present in the urban environment of São Paulo city at sites where large numbers of people normally gather.

Response of Eucalyptus tereticornis to inoculation with indigenous AM fungi in a semiarid alfisol achieved with different concentrations of available soil P

Eucalyptus tereticornis was grown in a green house in a low phosphorus (0.67 ppm Olsen's P) soil (Typic Haplustalf) inoculated with mixed indigenous arbuscular mycorrhizal (AM) fungi. Soil was amended to achieve P levels of 10, 20, 25, 30 and 40 ppm to evaluate the growth response and dependence of E. tereticornis to inoculation with AM fungi. A positive response to mycorrhizal inoculation was evident at the first two levels of soil P, i.e., at 0.67 and 10 ppm but not at the higher levels of soil P. Dry matter yield of inoculated plants beyond 20 ppm soil P was similar or even less compared to their uninoculated counterparts. Inoculated plants produced maximum dry matter (root and shoot) at 10 ppm soil P, whereas uninoculated plants did not produce until the level reached 20 ppm. The percentage root length colonized by AM fungi decreased from 31% to 3% as the concentration of P increased beyond 10 ppm soil P. Higher levels of soil P depressed the AM colonization significantly. Inoculated plants had higher shoot P and N contents compared to their uninoculated counterparts at all levels of soil P. However, at the first two lower levels of soil P, inoculated plants showed significantly higher shoot P and N contents over their respective uninoculated counterparts. The increasing shoot P accumulation beyond 10 ppm did not enhance dry matter yields. Inoculated plants had lower values of phosphorus utilization efficiency (PUE) and nitrogen utilization efficiency (NUE) at all levels of soil P except at the unamended level (0.67 ppm) where the inoculated plants showed higher values of NUE compared to uninoculated control plants. Taking dry matter yield into consideration, Eucalyptus plants were found to be highly dependent on 10 ppm of soil P for maximum dry matter production. Any further amendment of P to soil was not beneficial neither for AM symbiosis nor plant growth.

Hypaphorine from the ectomycorrhizal fungus Pisolithus tinctorius counteracts activities of indole-3-acetic acid and ethylene but not synthetic auxins in eucalypt seedlings

Very little is known about the molecules regulating the interaction between plants and ectomycorrhizal fungi during root colonization. The role of fungal auxin in ectomycorrhiza has repeatedly been suggested and questioned, suggesting that, if fungal auxin controls some steps of colonized root development, its activity might be tightly controlled in time and in space by plant and/or fungal regulatory mechanisms. We demonstrate that fungal hypaphorine, the betaine of tryptophan, counteracts the activity of indole-3-acetic acid (IAA) on eucalypt tap root elongation but does not affect the activity of the IAA analogs 2,4-D ((2,4-dichlorophenoxy)acetic acid) or NAA (1-naphthaleneacetic acid). These data suggest that IAA and hypaphorine interact during the very early steps of the IAA perception or signal transduction pathway. Furthermore, while seedling treatment with 1-amincocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, results in formation of a hypocotyl apical hook, hypaphorine application as well as root colonization by Pisolithus tinctorius, a hypaphorine-accumulating ectomycorrhizal fungus, stimulated hook opening. Hypaphorine counteraction with ACC is likely a consequence of hypaphorine interaction with IAA. In most plant-microbe interactions studied, the interactions result in increased auxin synthesis or auxin accumulation in plant tissues. The P. tinctorius / eucalypt interaction is intriguing because in this interaction the microbe down-regulates the auxin activity in the host plant. Hypaphorine might be the first specific IAA antagonist identified.

First environmental isolation of Cryptococcus neoformans var. neoformans and var. gatti from the Gharbia Governorate, Egypt

Flowers from two Eucalyptus camaldulensis trees in the Qutur area and one tree from the Tanta area yielded three isolates of Cryptococcus neoformans var. gattii. Pigeon and sparrow droppings were also investigated for the occurrence of C. neoformans within the study area. Ninety five isolates of the neoformans variety of C. neoformans were recovered from 550 samples of avian droppings.

Dispersed polyphosphate in fungal vacuoles in Eucalyptus pilularis/Pisolithus tinctorius ectomycorrhizas

Ectomycorrhizas produced between Pisolithus tinctorius and Eucalyptus pilularis under axenic conditions were rapidly frozen, freeze-substituted in tetrahydrofuran and embedded anhydrously, and dry-sectioned for X-ray microanalysis. The vacuoles of the sheath and Hartig net hyphae were rich in phosphorus and potassium. They also contained sulfur and variable amounts of chlorine. In anhydrously processed freeze-substituted mycorrhizas, dispersed electron-opaque material filled the fungal vacuoles. X-ray maps indicated that P was distributed evenly throughout the entire vacuole profile and was not concentrated in spherical bodies or subregions of the vacuole. There were no electron-opaque granules surrounded by electron-lucent areas, such as are commonly seen in chemically fixed material. The fungal vacuoles were also rich in K, which similarly gave a signal from the entire vacuolar profile. Such P-rich vacuoles occurred in both the mycorrhizal sheath and Hartig net hyphae. Stained sections of ether-acrolein freeze-substituted mycorrhizas also showed only dispersed material in the fungal vacuoles as, in most cases, did acetone-osmium freeze-substituted material. Precipitation of metachromatic granules by ethanol suggested that large amounts of polyphosphate are stored in these regions under the conditions of our experiments, as well as in the tips of actively growing hyphae of the same fungus. The higher plant vacuoles of ectomycorrhizas gave a much lower signal for K, and P was barely detectable. Much more K was located in the vacuoles of the root exodermal cells than in epidermal cells. The analysis of element distribution between the vacuole and cytoplasm in root cells agrees well with that found for other plant species using other techniques. We conclude that polyphosphate is indeed present in the vacuoles of the fungal cells of these ectomycorrhizas, but that in vivo it is in a dispersed form, not in granules.

A novel class of ectomycorrhiza-regulated cell wall polypeptides in Pisolithus tinctorius

Development of the ectomycorrhizal symbiosis leads to the aggregation of fungal hyphae to form the mantle. To identify cell surface proteins involved in this developmental step, changes in the biosynthesis of fungal cell wall proteins were examined in Eucalyptus globulus-Pisolithus tinctorius ectomycorrhizas by two-dimensional polyacrylamide gel electrophoresis. Enhanced synthesis of several immunologically related fungal 31- and 32-kDa polypeptides, so-called symbiosis-regulated acidic polypeptides (SRAPs), was observed. Peptide sequences of SRAP32d were obtained after trypsin digestion. These peptides were found in the predicted sequence of six closely related fungal cDNAs coding for ectomycorrhiza up-regulated transcripts. The PtSRAP32 cDNAs represented about 10% of the differentially expressed cDNAs in ectomycorrhiza and are predicted to encode alanine-rich proteins of 28.2 kDa. There are no sequence homologies between SRAPs and previously identified proteins, but they contain the Arg-Gly-Asp (RGD) motif found in cell-adhesion proteins. SRAPs were observed on the hyphal surface by immunoelectron microscopy. They were also found in the host cell wall when P. tinctorius attached to the root surface. RNA blot analysis showed that the steady-state level of PtSRAP32 transcripts exhibited a drastic up-regulation when fungal hyphae form the mantle. These results suggest that SRAPs may form part of a cell-cell adhesion system needed for aggregation of hyphae in ectomycorrhizas.

Isolation of Cryptococcus neoformans var. gattii from Eucalyptus camaldulensis in India

Cryptococcus neoformans var. gattii has an ecological association with five Eucalyptus species: E. blakelyi, E. camaldulensis, E. gomphocephala, E. rudis, and E. tereticornis. After human infections due to C. neoformans var. gattii were diagnosed in the states of Punjab, Himachal Pradesh, and Karnataka, India, a study was undertaken to investigate the association of C. neoformans var. gattii with Indian eucalypts, especially in the state of Punjab. A total of 696 specimens collected from E. camaldulensis, E. citriodora and E. tereticornis (hybrid) trees were examined for the presence of C. neoformans var. gattii. Flowers from two trees of E. camaldulensis in the Chak Sarkar forest and one from the village of Periana near the Ferozepur area yielded five isolates of C. neoformans var. gattii. The origin of the trees could be traced to Australia, thus providing evidence that the distribution of E. camaldulensis correlated with the distribution of human cryptococcosis cases caused by C. neoformans var. gattii in northern India.

Cryptococcus neoformans in Papua New Guinea: a common pathogen but an elusive source

Around Port Moresby, Papua New Guinea (PNG), the annual incidence of cryptococcal meningitis is estimated to be up to 42.8 per million population; Cryptococcus neoformans var. gattii is the predominant causative agent. In Australia and California, environmental isolations have established an ecological association of C. neoformans var. gattii with Eucalyptus camaldulensis, E. tereticornis, and more recently E. rudis and E. gomphcephala. In PNG few E. camaldulensis survive experimental planting, E. tereticornis is endemic and there are no records of planting of the non-endemic E. rudis and E. gomphcephela. Despite extensive sampling of eucalypt-associated and other sources, we were unable to identify the ecological niche of C. neoformans var. gattii and neoformans in this region.

Eucalypt alpha-tubulin: cDNA cloning and increased level of transcripts in ectomycorrhizal root system

Because symbionts are experiencing major morphological changes during ectomycorrhiza development, the expression of genes encoding cytoskeletal proteins is likely altered. To test this contention, we have cloned and characterized in a alpha-tubulin cDNA (EgTubA1) from Eucalyptus globulus. A poorly-aggressive isolate (No. 270) of the ectomycorrhizal basidiomycete Pisolithus tinctorius caused no changes in root transcript levels of EgTubA1, whereas a drastic up-regulation in its expression was observed between 3 to 4 days after contact with the aggressive isolate 441. This enhanced alpha-tubulin expression coincided with the increase lateral root formation induced by fungal colonisation. The changes in alpha-tubulin expression support a role for cytoskeleton components in ectomycorrhiza development.

Natural environmental sources of Cryptococcus neoformans var. gattii

We sought evidence for new environmental sources of Cryptococcus neoformans var. gattii by random amplification of polymorphic DNA (RAPD) analysis of isolates from 29 animals with a restricted territorial range in five Australian states. Twenty-three of the 29 isolates and 45 of 45 eucalypt isolates tested previously exhibited one RAPD profile, VGI. RAPD profile VGII was identified in 6 of 17 isolates from domesticated species but in none of 12 native species. Four VGII isolates originated from an area of Western Australia with no natural stands of known eucalypt host, indicating the existence of at least one unrecognized natural source of C. neoformans var. gattii.

Concordance of clinical and environmental isolates of Cryptococcus neoformans var. gattii by random amplification of polymorphic DNA analysis and PCR fingerprinting

Sixty-one clinical and forty-nine environmental isolates of Cryptococcus neoformans var. gattii from Australia and the United States were analyzed by random amplification of polymorphic DNA (RAPD), using 12- to 22-mer primers in pairs, and/or PCR fingerprinting with a single primer derived from the microsatellite core sequence of the wild-type phage M13 (5' GAGGGTGGCGGTTCT 3'). Three major genetic profiles were identified by both typing techniques. A single RAPD profile (VGI) predominated among clinical isolates (44 of 48, 92%) and isolates from host eucalypts (45 of 45, 100%) from Australia. Of the 94 Australian isolates, 4 (3 clinical and 1 environmental) were assigned to profile VGII; 2 of these were recovered from patients and one was recovered from plant debris from Western Australia. Only one Australian clinical isolate was assigned to profile VGIII. A different distribution of RAPD profiles (four VGIII, two VGII, and one VGI) was found among four clinical and three environmental isolates from the United States. RAPD profiles of 8 of the 101 isolates studied revealed minor genetic variants, 4 of profile VGI and 4 of profile VGII. Genetic concordance between the majority of clinical and environmental isolates in Australia is consistent with the hypothesis that human disease is acquired from exposure to host eucalypts. Profiles of clinical isolates were independent of body site of infection, and profiles of all isolates were stable over time. Analysis by PCR fingerprinting confirmed the RAPD results. A second RAPD profile (VGII) was associated with infection in southwest Western Australia, where the two host eucalypts do not occur naturally. This raises the possibility of an alternative and as yet unidentified natural habitat of C. neoformans var. gattii. Our results indicate that RAPD analysis is a sensitive and useful method for investigating environmental sources of human infection with this biotype.

Cloning and and characterization of hydrophobins-encoding cDNAs from the ectomycorrhizal basdiomycete Pisolithus tinctorius

Major alterations of fungal gene expression are induced by the development of ectomycorrhiza, a symbiosis between tree roots and filamentous fungi. Several cDNAs corresponding to highly expressed transcripts of the Basidomycete Pisolithus tinctorius (Pt) were isolated from symbiotic tissues. Two of these abundant transcripts (hydPt-1 and hydPt-2) encoded polypeptides belonging to the hydrophobin (Hyd) family, a group of small cysteine-rich fungal proteins involved im morphogenesis and plant-fungus interactions. As shown for other Hyd, the hydPt-1 and hydPt-2 mRNAs were barely detectable in mycelium grown in liquid culture and highly accumulated in aerial hyphae. In addition, these transcripts were also abundant in eucalyptus globulus-Pt ectomycorrhiza in early stages of differentiation, during the colonisation of roots.

Expressed sequence tags of randomly selected cDNA clones from Eucalyptus globulus-Pisolithus tinctorius ectomycorrhiza

Random sequencing of cDNA clones from Eucalyptus globulus-Pisolithus tinctorius ectomycorrhizal tissues was carried out to generate expressed sequence tags (ESTs). Database comparisons revealed that 42% of the cDNAs corresponded to previously sequenced genes. These ESTs represent efficient molecular markers to analyze changes in gene expression during the formation of the ectomycorrhizal symbiosis.

[Association of yeasts of the Cryptococcus genus with Eucalyptus species in Santafé de Bogotá]

Environmental isolation of Cryptococcus neoformans var. gattii was first made in Australia in 1989 by ELLIS. He established a specific association with the tree species Eucalyptus camaldulensis and E. tereticornis. Based on his findings, ELLIS proposed that the fungus could be exported from Australia to others regions, including Colombia, by means of infected seeds. The purpose of this study was to isolate and identify Cryptococcus sp., associated with Eucalyptus trees; this is the first ecological evaluation of C. neoformans var. gattii in our country. A total of 100 Eucalyptus trees, distributed among 13 zones, located in the center, northeast, east and west of Santafé de Bogotá, were studied. Flowers, fruits, leaves, barks and Eucalyptus debris were collected. The samples were processed by extraction with saline solution containing antibiotics, cultured in selective media and the isolates were identified by morphological and biochemical characterístics. Twenty-seven isolates of 9 Cryptococcus sp. were recovered from 21 Eucalyptus trees, from 5 zones. One C. neoformans var. neoformans serotype A was recovered. The Cryptococcus associated with Eucalyptus is important because this is the first study done in our country.

Ecology, life cycle, and infectious propagule of Cryptococcus neoformans

Cryptococcus neoformans is a biotrophic smut-like fungus, and the epidemiology of cryptococcosis can mainly be explained by exposure to an infective aerosolised inoculum. For C neoformans var gattii it is postulated that the principal infectious propagule is the basidiospore and that exposure to Eucalyptus camaldulensis, the host tree, is required to initiate infection in man and animals. C neoformans var gattii may have been exported from Australia by infected seeds of E camaldulensis containing dormant dikaryotic mycelium of the fungus. For C neoformans var neoformans both the basidiospore and desiccated encapsulated yeast cells are postulated to act as infectious propagules, the basidiospores showing a seasonal distribution in association with an as yet unidentified host plant, and the encapsulated yeast cells dispersed from accumulations of dried bird (mainly pigeon) droppings which act as a year-round vector.