Whole-Genome Sequencing of an Uncommon Cryptococcus neoformans MLST43 Genotype Isolated in Nigeria

Mycopathologia - Cryptococcosis is a human infection caused mainly by two species of the Cryptococcus genus, Cryptococcus neoformans and Cryptococcus gattii, whose populations contain several...     

Human defenses against Cryptococcus neoformans: An update

Cryptococcus neoformans var. neoformans is an opportunistic fungal pathogen, especially in AIDS patients, and is found world-wide. On the other hand, Cryptococcus neoformans var. gatti (CN-g) is restricted to an association with two species of Eucalyptus trees. Alveolar macrophages (AM) constitute the first line of defense to Cryptococcus neoformans and offers some resistance. The inflammatory response to Cryptococcus neoformans with an influx of neutrophils and monocytes affords a second line of defense. Secretion of proinflammatory monokines by human AM is now being defined. The inflammatory phagocytes are efficient in killing Cryptococcus neoformans and offer strong resistance. T and B cell responses to infection, a third line of defense, results in production of lymphokines (IFNg, etc.) and specific antibodies. Enhancement of lymphocyte responses by IL-12 and IL-18 to Cryptococcus neoformans infection appears to be critical. Susceptibility of AIDS patients to Cryptococcus neoformans is associated with low CD4+ T cell counts and likely reduced efficacy of the second line of defense. This revised version was published online in June 2006 with corrections to the Cover Date.     

新生隐球菌的酚氧化酶及用于菌种鉴定的研究

采用4％玉米浸汁咖啡酸琼脂(CACA)培养基。观察了具不同生物学特性的新生隐球菌的酚氧化酶活性,并对临床常见的多种酵母和酵母样真菌作了该酶的检测。结果,受试的3个变种、5种血清型和尿素酶阴性新生隐球菌均呈明确的阳性反应;150株常见酵母和酵母样真菌中43株新生隐球菌全部呈酚氧化酶阳性。107株其它酵母和酵母样真菌全部阴性。具各种不同生物学特性的新生隐球菌均特异性地产生酚氧化酶,用检测该酶的方法作该菌鉴定的特异性和敏感性均为100％,且可于72小时内得到结果。此外,结合尿素酶试验可以准确的鉴定出尿素酶阴性的新生隐球菌。     

Cryptococcus bestiolae and Cryptococcus dejecticola, two new yeast species isolated from frass of the litchi fruit borer Conopomorpha sinensis Bradley

Two new yeast species, Cryptococcus bestiolae and Cryptococcus dejecticola, were discovered in the frass of the litchi fruit borer Conopomorpha sinensis Bradley. The yeasts utilize inositol, hydrolyze urea, produce starch-like substance, and contain CoQ10. Phylogenetic analyses of D1/D2 26S rDNA and internal transcribed spacer (ITS) sequences indicate that the yeasts are closely related to Bullera dendrophila and an undescribed species of Cryptococcus (strain CBS 8507). The two new species differed from each other by 17 nucleotides in the D1/D2 region and by 68 nucleotides in the ITS region. Cryptococcus bestiolae is a sister species to Cryptococcus sp. CBS 8507, from which it differs by eight nucleotides in the D1/D2 region and 59 nucleotides in the ITS region. Cryptococcus dejecticola and B. dendrophila differed by 13 nucleotides in the D1/D2 and 57 nucleotides in the ITS region. Cryptococcus bestiolae and Cr. dejecticola formed with B. dendrophila a well defined clade consisting of insect associated species. The type strain of Cr. bestiolae is TH3.2.59 (=CBS 10118=NRRL Y-27894), and the type strain of Cr. dejecticola is Litch 17 (=CBS 10117=NRRL Y-27898).     

新生隐球菌生物膜动物感染模型的构建及其活性的检测

目的 构建一种简便易行的新生隐球菌生物膜感染动物模型.方法 采用大鼠皮下置管法构建新生隐球菌生物膜感染动物模型,并使用电子扫描显微镜观察新生隐球菌体内形成生物膜的结构;采用MTT法对获得的体内生物膜结构进行活性的检测.结果 成功构建了新生隐球菌生物膜大鼠感染模型;MTT法检测体内生物膜活性表明,随着体内培养时间的延长,生物膜活性增强,与直接镜检和电镜观察结果一致.结论 新生隐球菌生物膜大鼠模型简单易行,便于操作,对于研究新生隐球菌生物膜体内活性的研究具有一定的实际应用价值.     

格特隐球菌病暴发流行机制的研究进展

目前已证实, 格特隐球菌病可暴发流行。近10 年来, 在加拿大温哥华岛暴发的格特隐球菌病发病率显著高于其他地区, 且大部分感染者免疫力正常, 该致病菌已蔓延至周边地区。本文就格特隐球菌病暴发流行机制, 包括致病菌的分子流行病学分析、可能来源、毒力分析和播散机制进行综述。     

新生隐球菌感染小鼠肺泡巨噬细胞相关细胞因子与疾病病程相关性研究

目的通过检测新生隐球菌感染小鼠巨噬细胞相关细胞因子的表达水平,探讨其在感染小鼠疾病病程的作用。方法应用单侧小鼠鼻孔接种感染新生隐球菌建立小鼠吸入感染隐球菌模型,在感染后第1、4、7、11、14、18、21天,PAS染色观察小鼠肺组织病理变化,并通过RT-PCR检测相应时间点小鼠巨噬细胞内相关细胞因子(IL-6、IL-8、TGF-β、TNF-α)的表达。结果小鼠吸入感染隐球菌后,PAS染色发现第4天肺内散在分布隐球菌,第7天可见肉芽肿形成,第11天大量炎性细胞浸润,第14天见肉芽肿内大量隐球菌,第18天隐球菌分布至全肺,第21天肺组织大量坏死;RT-PCR结果显示TGF-β和IL-6的表达在感染后14天达到最高值,然后逐渐降低,其中TGF-β升高幅度更为明显。结论在新生隐球菌感染小鼠中,TGF-β参与了机体的抗真菌免疫,在调节炎症反应方面有重要作用。     

Know Your Enemy: How to Build and Vanquish a Global Fungal Scourge

The 8th International Conference on Cryptococcus and Cryptococcosis, chaired by Maurizio Del Poeta (Medical University of South Carolina), and organized together with June Kwon-Chung (National Institute of Allergy and Infectious Diseases), Stuart Levitz (University of Massachusetts Medical School), and John Perfect (Duke University), occurred in May 2011. This meeting brought together the world's leading researchers on Cryptococcus and cryptococcosis, including basic scientists, epidemiologists, and clinicians, to discuss new developments in Cryptococcus biology. With more than 60 oral presentations and 180 posters, this meeting enhanced our understanding of pathogenicity of Cryptococcus and served as a robust forum that facilitated cross-disciplinary discussions, research, and clinical collaborations. Due to space constraints, this brief overview highlights only a few of the topics discussed in this meeting, focusing on the evolution of virulence, host and pathogen interactions, fungal and host signaling, new advances of genomics studies on Cryptococcus, and the current status of the outbreak caused by C. gattii. The 8th International Conference on Cryptococcus and Cryptococcosis brought together scientists from across the globe in the beautiful historical downtown setting of Charleston to share their latest findings and highlight advances in Cryptococcus research. With more than 250 participants, this meeting was the largest gathering of the Cryptococcus international community in the 24-year history. Here, we review the advances presented and the current state of knowledge in the field.     

Cryptococcus tephrensis,sp.nov., and Cryptococcus heimaeyensis,sp.nov.; new anamorphic basidiomycetous yeast species from Iceland

Two new species from Iceland are described on the basis of physiological profiles and sequence data from the D2 region of LSU rDNA: Cryptococcus tephrensis (type ICE99-IToM Y5, ATCC MYA-1765, CBS 8935, GenBank AF317208) and Cryptococcus heimaeyensis (type ICE99-IToM Y8, ATCC MYA-1759, CBS 8933, GenBank AF370717). The two new species are identifiable from sequence data and can be distinguished from their closest relative, Cryptococcus victoriae, by their higher maximum temperatures for growth, failure to utilize nitrate as sole nitrogen source, and utilization of cadaverine and ethylamine as sole nitrogen sources. Cryptococcus tephrensis is distinguishable from C. heimaeyensis by failure to grow on saccharate as sole source of carbon and energy.     

Pseudomonas aeruginosa Inhibits the Growth of Cryptococcus Species

Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.     

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.     

Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov., Antarctic basidioblastomycetes

New yeasts from the Ross Desert (dry valley area) of Antarctica include Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov. Cryptococcus socialis MYSW A801-3aY1 (= ATCC 56685) requires no vitamins, assimilates L-arabinose, cellobiose, D-glucuronate, maltose, melezitose, raffinose, soluble starch, sucrose, and trehalose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production, cellobiose assimilation, and failure to utilize nitrate, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%. Cryptococcus consortionis MYSW A801-3aY92 (= ATCC 56686) requires thiamine, assimilates L-arabinose, D-glucuronate, 2-ketogluconate, salicin, succinate, sucrose, trehalose, and D-xylose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production and failure to utilize nitrate, cellobiose, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%.     

Asterotremella gen. nov. albida, an anamorphic tremelloid yeast isolated from the agarics Asterophora lycoperdoides and Asterophora parasitica

Using a genotypic approach (PCR-fingerprinting, DNA/DNA reassociation, partial sequences of the 26S rDNA gene, complete sequences of the 18S rDNA gene, and sequences of the internal transcribed spacers) five tremelloid yeast isolates from the agarics Asterophora lycoperdoides and A. parasitica were shown to be conspecific with Cryptococcus ramirezgomezianus. It was not possible to distinguish the yeast strains from A. lycoperdoides and A. parasitica using sequences from the intergenic spacer (IGS1). Phylogeny based on the 26S (D1/D2-domain), ITS1-5.8S-ITS2 and complete 18S rDNA demonstrated that C. ramirezgomezianus is closely related to several additional Cryptococcus species (C. humicola, C. longus, C. musci, C. pseudolongus) within the Trichosporonales. A new genus, Asterotremella, and a new family, Asterotremellaceae were introduced for Cryptococcus species clustering within the Trichosporonales having a ubiquinone Q-9. Cryptococcus ramirezgomezianus is a synonym of Asterotremella albida.     

Cryptococcus festucosus sp. nov. a new hymenomycetous yeast in the Holtermannia clade

Five yeast strains belonging to the genus Cryptococcus Vuillemin were isolated from steppe plants and turf collected in the Prioksko-terrasny biosphere reserve (Moscow region, Russia). Sequence analyses of the D1/D2 domains of the 26S rDNA and of the internal transcribed spacer region revealed that these yeast strains and strain CBS 8016 have almost identical sequences and belong to the Holtermannia clade of the Tremellomycetidae (Basidiomycota, Hymenomycetes). A novel species named Cryptococcus festucosus (type strain VKM Y-2930) is proposed to accommodate these strains. Physiological characteristics and mycocin sensitivity patterns distinguishing Cryptococcus festucosus from the other species of this clade are presented.     

Molecular characterization and evaluation of virulence factors of Cryptococcus laurentii and Cryptococcus neoformans strains isolated from external hospital areas

Cryptococcosis is a common opportunistic fungal infection that is mainly caused by the species Cryptococcus neoformans and Cryptococcus gattii, but there have recently been several reports of infection by non-neoformans Cryptococcus species. The aims of this study were to genetically characterize Cryptococcus spp. isolated from external hospital areas in Minas Gerais State, Brazil, and to evaluate their pathogenic potential, analyzing their phospholipase and melanin production and the capacity for capsule enlargement. Seventy-three different samples were collected: 62 from bird droppings and 11 from tree detritus. C.?neoformans alone was isolated from 43.8% of the samples, Cryptococcus laurentii alone from 23.3% and both fungi were found together in 10.9%. C. laurentii was exclusively isolated from 45% (5/11) of the tree samples (Anacardium occidentale, Guazuma ulmifolia, Mangifera indica and Ficus benjamina). Among the 51 C. neoformans isolates, 47 were classified as type VNI and four as type VNII. All of the C. neoformans isolates were of MATα type. Among the 21 isolates of C. laurentii genotyped using the URA5-RFLP technique, 16 amplified a 1.6kb amplicon which produced a specific restriction profile in 15 isolates. In C.?neoformans, 76.4% of the isolates were capable of capsule enlargement in the induction medium and 92.1% were phospholipase producers. In C. laurentii, 7.4% of the isolates were capable of capsule enlargement and 85.1% were phospholipase producers. Characterization of the genotypes and the pathogenic potential of the Cryptococcus spp. isolates studied may contribute towards better understanding of the epidemiology of cryptococcosis and the ecology of agents causing this disease in our region.     

Cryptococcus curvatus O3酵母菌培养及产油脂特性

生物柴油的发展, 导致全球油脂供求紧张。微生物油脂的甘三酯组成与植物油类似, 发展微生物油脂可部分缓解植物油脂供应压力。本文研究了Cryptococcus curvatus O3酵母利用葡萄糖为碳源生长和积累油脂的特性。Cryptococcus curvatus O3酵母在培养过程中能适应间歇式碳源流加方式达到高密度培养的目的, 但在相同培养条件下, 不同氮源能影响其代谢过程中糖到油脂转化的脂肪系数。Cryptococcus curvatus O3酵母利用葡萄糖作为碳源在30°C下摇瓶发酵, 菌体生物量为51.8 g/L, 油脂含量达65.1%。脂肪酸组成分析结果表明, 菌油富含饱和及低度不饱和长链脂肪酸, 其中饱和脂肪酸之和占总脂肪酸组成的64%左右, 其脂肪酸组成类似于可可脂, 这些结果对于利用产油微生物转化生物质获取如类可可脂等具有高附加值油脂的研究具有重要意义。     

Cryptococcus adeliensis sp. nov., a xylanase producing basidiomycetous yeast from Antarctica

Cryptococcus adeliensis sp. nov. (CBS 8351) is described based on phenotypic characteristics and molecular sequence analysis of the D1/D2 large subunit and internal transcribed spacer regions of the ribosomal DNA. Molecular comparisons include species closely related to Cryptococcus albidus and several species isolated from the Antarctic. C. adeliensis, which has a cold-adapted xylanase, was isolated from Terre Adelie, Antarctica. ATCC 34633, which has a mesophilic xylanase, was identified as Cryptococcus albidosimilis.     

新生隐球菌STE12α基因的克隆及表达载体的构建

目的从新生隐球菌的基因组中扩增出STE12α基因,并构建相应的表达载体,以进一步研究STE12α基因对隐球菌的生长特性及致病性的影响。方法采用PCR方法以及基因重组方法扩增并克隆新生隐球菌基因组中的STE12α基因,建立具有表达野生型STE12α基因的表达载体。结果从新生隐球菌的基因组获得STE12α全基因,建立重组子pUCm—STE12α／NovaBlue以及重组表达载体质粒pGAPZ—STE12α,实现了STE12α基因的转化并获得表达。结论成功地克隆了新生隐球菌STE12α基因并构建了可表达野生型STE12α基因的表达载体,为进一步研究STE12α基因功能打下了良好的基础。     

Attempted Isolation of Cryptococcus Species and Incidental Isolation of Exophiala dermatitidis from Human Oral Cavities

Mycopathologia - Recent molecular studies suggest that Cryptococcus may inhabit the normal human mouth. We attempted to isolate Cryptococcus from 21 adult non-acutely ill patients and 40 volunteer...