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1.
Cryptococcus neoformans and Cryptococcus gattii are pathogenic yeasts that cause cryptococcosis. These fungi were commonly associated with pigeon droppings and plant materials. The habitat of these pathogens has not been yet studied in Tunisia, although the ecology of these yeasts must be elucidated in order to establish surveillance programs and to prevent infections. The aim of this survey was to recover C. neoformans and C. gattii environmental isolates from pigeon droppings and plant materials in different areas of Sfax region, Tunisia. Nine hundred and fifty samples from leaves, wood, flowers, fruits and soil around trunk bases of 40 almond (Prunus dulcis) and 60 eucalyptus trees were collected as well as 250 pigeon droppings samples from different sites: buildings (n = 150), houses (n = 50) and zoo (n = 50). The identification of Cryptococcus neoformans complex was confirmed using the ID32C auxanogram panel (BioMérieux, Marcy l’Etoile, France); species were determined by multiplex PCR using the CN70 and CN49 primers, and mating type was determined by PCR. C. neoformans was recovered from 26 specimens of pigeon droppings (10.4%). This yeast was obtained more frequently from dry droppings (9.2%) than from moist droppings (1.2%). The mating type was determined. All the 31 environmental strains of C. neoformans and C. gattii were MATα. Out of 700 samples tested from 100 trees, only 5 isolates of Cryptococcus neoformans species complex were recovered (0.6%), two isolates of C. gattii and one isolate of C. neoformans were recovered from the wood of E. camaldulensis trees, and only two isolates of C. gattii were recovered from the wood of almond trees (Prunus dulcis Mill. var. zaaf and var. achek). These two Tunisian almond tree varieties were recorded for the first time in Africa as hosts for C. gattii. These results add new information to the ecology and epidemiology of C. neoformans species complex in Tunisia.  相似文献   

2.
The genus Cryptococcus includes free-developing species, a few of which are of medical importance. Some, such as C. neoformans and C. gattii, cause infections in man frequently and C. albidus and C. laurentii cause less so. The aims of this study were to evaluate organ colonization after inoculation of C. albidus and C. laurentii isolates in normal BALB/c mice, the virulence factors (growth at 37°C, capsule, melanin, proteinase, and phospholipase production) and the molecular profile (PCR-fingerprinting) of the yeasts before and after infection. The importance of different profiles (virulence and molecular) was considered in relation to the distribution in different organs and to the time intervals of isolation from organs. C. albidus was isolated from animal organs 2 to 10 days after inoculation and C. laurentii from 2 to 120 days. Most isolates of the two species kept the virulence factors showed before inoculation. The high homogeneity of the molecular profile of C. albidus and the high heterogeneity of C. laurentii were kept through the passages in animals. It is concluded that most isolates of both species were recovered from the animal organs after 5 or more days, and phenotypes were not altered by inoculation. No molecular alteration was detected and the virulence factors were not related to the time intervals before isolation from organs.  相似文献   

3.
A total of 36 Cryptococcus neoformans strains originating from South Africa were screened for wood degrading enzymes. All strains tested positive for cellulase activity while none where capable of xylan degradation. Three C. neoformans var. grubii strains, originating from clinical and environmental samples, representing the same genotype (VNI/AFLP1—C. neoformans var. grubii) and MATα, were evaluated for growth on debris of two common tree species in South Africa: Acacia mearnsii and Eucalyptus camaldulensis. The mating capability of all the C. neoformans strains was evaluated on similar debris. Strains grown on A. mearnsii yielded substantially greater yeast populations. A total of 26%, 6%, 46%, and 80% of the 36 C. neoformans strains tested were either able to mate or develop filaments when crossed on A. mearnsii and E. camaldulensis debris, V8 juice, and yeast carbon base (YCB) agar, respectively. Filamentation and monokaryotic fruiting was observed in 3% of strains when C. neoformans was cultured on either A. mearnsii, E. camaldulensis debris, or YCB. The results indicate that this fungus is capable of completing its life cycle and can produce basidiospores on woody debris. In the future, these findings should be considered when studying the epidemiology, microbial ecology, and proposed infection process of this global pathogen.  相似文献   

4.
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. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

5.
Field observations and inoculation experiments revealed that Uromyces appendiculatus var. azukicola has an autoecious and macrocyclic life cycle and produces spermogonia, aecia, uredinia, and telia on Vigna angularis var. angularis and V. angularis var. nipponensis. From inoculation experiments, it was suggested that this rust fungus has different host relationships from other varieties. Morphological examinations revealed that the characteristics of urediniospores and teliospores are different among varieties, although aeciospores are morphologically similar to each other.Contribution no. 182, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan  相似文献   

6.
A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan  相似文献   

7.
Encapsulated yeast, Cryptococcus gattii (Cg) is a primary and emerging fungal pathogen in North America. It has a predilection for invading the central nervous system of both healthy and immunocompromised humans and animals. Recently, we initiated molecular pathogenesis studies in Cg strain NIH444 (ATCC 32609). In this report, we compared the biology and pathogenic potential of NIH444 to those of WM276, an Australian environmental isolate that is being used for the whole genome-sequencing project. Our data indicated that NIH444 is comparatively more virulent in a mouse model of cryptococcosis than is WM 276. We found robust mating of NIH444, and no mating of WM276, when tested against Cg MATa strain, NIH198. WM276 but not NIH444 was defective in filamentation and sporulation (haploid fruiting). Interestingly, NIH444 has a VGII/AFLP6 genotype similar to that of the genotype of the recent outbreak strains from Vancouver Island, British Columbia, Canada. Additionally, comparisons of nucleotide sequences of various genes also showed differences between NIH444 and WM276. Based on these observations, we conclude that NIH444 should remain the strain of choice for understanding Cg pathogenesis, especially on the North American continent.  相似文献   

8.
Summary Catenaria anguillulae parasitized and killed the eggs and second stage juveniles (J2) of Meloidogyne graminicola under natural conditions. The percentage of infection in eggs was higher than J2 of M.␣graminicola, which ranged between 0–50.3% and 0–18.9% in 2004 and 0–46.6% and 0–21.7% in 2005, respectively. The higher parasitism of eggs and J2 was recorded from those fields in which plants were severely infected with M. graminicola. The degree of parasitism of eggs and J2 by C. anguillulae varied with severity of root knot disease. The fields with a higher root gall index recorded a higher percentage of infection in eggs and J2 of M. graminicola. In general, old galls when teased and incubated, recorded higher parasitism of eggs and juveniles than young galls.  相似文献   

9.
The occurrence of Cryptococcus neoformans in bird excreta in Klang valley, Malaysia was determined in this study. Of 544 samples of bird excreta collected from a local zoo, pet shops and public areas, 20 strains of C. neoformans were isolated. All C. neoformans strains were serotype A and thus identified as C. neoformans variety grubii. All did not produce color changes on canavanine–glycine–bromothymol blue agar. All were of α-mating types, as determined by a pheromone-specific PCR assay. The antifungal susceptibility testing using agar diffusion method Neo-sensitabs showed that all were susceptible to amphotericin B, fluconazole and itraconazole.  相似文献   

10.
Petra Hoffmann 《Brittonia》2008,60(2):136-166
Heterosavia (Phyllanthaceae) is segregated from Savia (tribe Bridelieae), recognized at generic rank, and placed in tribe Phyllantheae. Floral, fruit, leaf anatomical, leaf venation, and pollen characters of the neotropical taxa previously united as Savia including Gonatogyne are discussed and illustrated. Keys to the three genera and to the species of Heterosavia are presented. Four species (all new combinations), Heterosavia bahamensis, H. erythroxyloides, H. laurifolia, and H. maculata, are recognized. The new combinations Heterosavia laurifolia var. intermedia and H. maculata var. clementis are proposed. The names Heterosavia, H. erythroxyloides, H. laurifolia, Savia clementis, S. clusiifolia, S. clusiifolia var. fallax, and S. longipes are lectotypified. Distribution maps and conservation assessments (IUCN ratings) of Heterosavia species and varieties are provided.  相似文献   

11.
Cortinarius subalboviolaceus var. niigatensis var. nov., which grows in deciduous forests, is described and illustrated from Niigata and Gunma prefectures, Japan. It differs from C. subalboviolaceus var. subalboviolaceus mainly in its more distinct violet coloration and somewhat larger size of the basidiocarp.  相似文献   

12.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.  相似文献   

13.
14.
A Sebacinales species was recovered from a clone library made from a pooled rhizosphere sample of Nicotiana attenuata plants from 14 native populations. Axenic cultures of the related species, Piriformospora indica and Sebacina vermifera, were used to examine their effects on plant performance. Inoculation of N. attenuata seeds with either fungus species stimulated seed germination and increased growth and stalk elongation. S. vermifera inoculated plants flowered earlier, produced more flowers and matured more seed capsules than did non-inoculated plants. Jasmonate treatment during rosette-stage growth, which slows growth and elicits herbivore resistance traits, erased differences in vegetative, but not reproductive performance resulting from S. vermifera inoculation. Total nitrogen and phosphorous contents did not differ between inoculated and control plants, suggesting that the performance benefits of fungal inoculation did not result from improvements in nutritional status. Since the expression of trypsin proteinase inhibitors (TPI), defensive proteins which confer resistance to attack from Manduca sexta larvae, incur significant growth and fitness costs for the plant, we examined the effect of S. vermifera inoculation on herbivore resistance and TPI activity. After 10 days of feeding on S. vermifera-inoculated plants, larval mass was 46% higher and TPI activity was 48% lower than that on non-inoculated plants. These results suggest that Sebacina spp. may interfere with defense signaling and allow plants to increase growth rates at the expense of herbivore resistance mediated by TPIs.  相似文献   

15.
Termites, Coptotermes formosanus, reared individually, were highly susceptible to the entomopathogenic fungus, Metarhizium anisopliae, while termites reared in␣groups were highly resistant. When reared in groups, the termites treated with M.␣anisopliae conidia on the body surface were groomed by their nestmates and more than 80% of the conidia were removed from the cuticle within 3 h. However, there was not a significant reduction in the numbers of conidia on the body surfaces of termites reared individually. For the termites maintained in groups, conidia were found in foreguts, midguts and hindguts, but very few conidia were detected in the guts of termites reared individually. Conidia in the alimentary tracts did not germinate, but some of were alive. As a result, it seems that the removal of foreign bodies, such as fungal conidia, from the␣cuticle is one function of termite mutual grooming behavior and that conidia removed from the cuticle are eliminated through alimentary tracts. This study indicates that mutual grooming behavior is very effective in protecting these termites from M.␣anisopliae infection.  相似文献   

16.
About 63 fungal endophytic isolates were separated from rhizomes of Paris polyphylla var. yunnanensis, which is a traditional medicinal plant mainly distributed in China. The isolates were characterized and grouped based on the culture characteristics and the morphology of colony growth and conidia. Eleven representative ones were selected for further taxonomical identification. Five genera namely Fusarium, Gliocladiopsis, Gliomastix, Aspergillus and Cylindrocarpon were identified on the basis of their morphological characterizations. Of them, the most frequent genus was Fusarium (i.e. Ppf1, Ppf3 and Ppf14). Their ITS-rDNA sequences were compared with those available in the GeneBank databases to obtain the closest related species by BLAST analysis as well as to analyze their phylogenetic affiliation. The isolates were identified as Gliocladiopsis irregularis (Ppf2), Plectosphaerella cucumerina (Ppf4), Padospora sp. (Ppf6), Gliomastix murorum var. murorum (Ppf7), Aspergillus fumigatus (Ppf9), Pichia guilliermondii (Ppf10), Neonectria radicicola (anamorph: Cylindrocarpon) (Ppf12) and one uncultured mycorrhizal ascomycete (Ppf13) separately based on their morphological and molecular features. The molecular characters of the endophytic fungi were basically coincident with their morphology. The broad diversity and taxonomic spectrum were exhibited by the endophytic fungi from P. polyphylla var. yunnanensis.  相似文献   

17.
Over the past decades there has been a significant increase in fungal infections caused by Candida species, and continues to be common in immunocompromised individuals infected with the human immunodeficiency virus (HIV). Although Candida albicans remains the fungal species most frequently isolated as an opportunistic oral pathogen, other non-albicans are often identified in this cohort of patients, including C. dubliniensis. This yeast is closely related to and shares many phenotypic characteristics with C. albicans. Colonies of these two species appear morphologically identical when not grown on special media. The shared phenotypic characteristics of C. dubliniensis and C. albicans suggest that many C. dubliniensis isolates may have been misidentified as C. albicans in the past. The present studies aim is to recover and identify C. dubliniensis, and presumptive clinical C. albicans, from the oral cavities of HIV-seropositive individuals, comparing conventional media to obtain a simple, low-cost and reliable identification system for C. dubliniensis. A total of 16 isolates (3,98%) had been obtained from 402 HIV infected individuals with recurrent oropharyngitis and were identified as C. dubliniensis. Out of these C. dubliniensis isolates 19% were resistant, with MICs above 64 μg/ml to fluconazole. This constitutes, to the authors knowledge the first recovery of this organism in Venezuela.  相似文献   

18.
P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

19.
Sporulation in Bacillus megaterium var phosphaticum (PB — 1) was induced using modified nutrient media. This modified medium induced sporulation within 36 h. After spore induction the spores were kept under refrigerated (5°C) and room temperature (32°C) for five months and survival of spores was studied at 15 days intervals by plating them in nutrient agar medium. It was observed that there was not much variation in the storage temperature (5°C & 32°C). The spore cells of Bacillus megaterium var phosphaticum (PB — 1) were observed up to five months of storage under refrigerated (5°C) and room temperature (32°C). Regeneration of spore cells into vegetative cells was studied in tap water, rice gruel, nutrient broth, sterile lignite and sterile water at different concentrations of spore inoculum. The multiplication of sporulated Bacillus megaterium var phosphaticum culture was fast and reached its maximum (29.5 × 108 cfu ml−1) in nutrient broth containing 5 per cent inoculum level.  相似文献   

20.
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