The atlas compiled by these editors is a commendable effort and welcome addition to the mycology textbook sector. Up until now, the publication of medical mycology textbooks has been sparse and those that have been published are either too detailed for a resident in training or practicing physician or do not provide sufficient photographs or illustrations of the main features of the mycotic organisms. As a lecturer in mycology for the dermatology residents at my local teaching hospital and program, there are 3 key objectives of my mycology lectures: (1) to provide some type of organizational approach to mycotic organisms, (2) to provide a concise clinical history, and (3) to provide as many photographs and illustrations of mycotic organisms as possible. This atlas provides an exemplary addition to my book collection on medical mycology textbooks and sources for illustrations of mycotic organisms. The electron photomicrographs, photoplates, and line drawings of

Atlas of Clinical Fungi

Pullulan: Microbial sources, production and applications

The genus Cladosporium

Fungal infections, especially those caused by opportunistic species, have become substantially more common in recent decades. Numerous species cause human infections, and several new human pathogens are discovered yearly. This situation has created an increasing interest in fungal taxonomy and has led to the development of new methods and approaches to fungal biosystematics which have promoted important practical advances in identification procedures. However, the significance of some data provided by the new approaches is still unclear, and results drawn from such studies may even increase nomenclatural confusion. Analyses of rRNA and rDNA sequences constitute an important complement of the morphological criteria needed to allow clinical fungi to be more easily identified and placed on a single phylogenetic tree. Most of the pathogenic fungi so far described belong to the kingdom Fungi; two belong to the kingdom Chromista. Within the Fungi, they are distributed in three phyla and in 15 orders (Pneumocystidales, Saccharomycetales, Dothideales, Sordariales, Onygenales, Eurotiales, Hypocreales, Ophiostomatales, Microascales, Tremellales, Poriales, Stereales, Agaricales, Schizophyllales, and Ustilaginales).

/pdf/developments-in-fungal-taxonomy-4minwenpuf.pdf

Developments in Fungal Taxonomy

Summary: Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi Melanin is a likely virulence factor for these fungi Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants Therapy varies depending upon the clinical syndrome Local infection may be cured with excision alone, while systemic disease is often refractory to therapy Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections

Melanized Fungi in Human Disease

Diagnostic criteria for the distinction of the slightly osmophilic species,Aureobasidium pullulans, and the opportunistic pathogen on conifers,Hormonema dematioides, are provided. Reliable identification requires a combination of characters of conidiogenesis, expansion growth and assimilative abilities. Relationships with species ofKabatiella, and with the teleomorph generaPringsheimia, Dothidea andDothiora, all havingHormonema-like cultural states, are discussed. An identification key is provided.

Conidiogenesis, nutritional physiology and taxonomy of Aureobasidium and Hormonema.

The black yeast Aureobasidium pullulans (de Bary) Arnaud is known to synthesize the exopolysaccharide pullulan, a poly-alpha-1,6-maltotriose. Nine strains were found to produce additional aubasidan-like EPS, i.e. glucans with alpha-1,4-D-, beta-1,6-D- and beta-1,3-D-glycosidic bonds. These strains had previously been found to deviate in genotypic characters. Additional physiological differences were found: the optimal nitrogen source for exopolysaccharide production in liquid medium was NaNO3 for aubasidan-producing strains, and (NH4)2SO4 for the remaining strains. A new variety, A. pullulans var. aubasidani Yurlova, is described for the strains producing aubasidan-like components. The new variety can be distinguished from A. pullulans var. pullulans by the absence of assimilation of methyl-alpha-D-glucoside and lactose.

A new variety of Aureobasidium pullulans characterized by exopolysaccharide structure, nutritional physiology and molecular features

Summary. The black yeasts Exophiala spinifera and E. dermatitidis produce extracellular slimes, which may be either in the form of a well-delimited capsule or of diffusely exuded exopolysaccharides (EPS). The optimal conditions for their production were studied. The presence or absence of polysaccharide material can be used for recognition of the two species. Five-day-old cultures grown on potato glucose agar at 24 °C were observed in India ink, and positive identification for E. spinifera was obtained when significant halos were seen around yeast cells. In contrast, E. dermatitidis had irregular EPS with a fibrillar substructure made visible by alcian blue staining. Other Exophiala species produce insignificant amounts of extracellular mucus or none at all. The diagnostic method is particularly useful with yeast-like primary cultures, which often consist entirely of budding cells and lack the characteristic structures of the filamentous Exophiala synanamorph.



Zusammenfassung.  Die schwarzen Hefen Exophiala spinifera und E. dermatitidis produzieren extrazellularen Schleim, der begrenzt kapsularen Ursprungs sein oder von diffus ausgeschiedenen Exopolysacchariden (EPS) stammen konnte. Optimale Produktionsbedingungen dafur wurden untersucht. Die An- bzw. Abwesenheit von Polysaccharidmaterial kann fur die Identifizierung der beiden Spezies genutzt werden. Kulturen, die bei 24 °C auf Kartoffel-Glucose-Agar wuchsen, wurden nach 5 Tagen mit Tusche gefarbt. Bei E. spinifera bilden sich hierbei signifikante Hofe um die Hefezellen. Im Gegensatz dazu, hat das irregulare EPS von E. dermatitidis eine fibrillare Substruktur, die mit Alcian-Blau sichtbar wird. Andere Exophiala-Spezies produzieren keine oder sehr geringe extrazellulare Schleime. Diese diagnostische Methode ist besonders nutzlich bei Primarkulturen, die haufig nur aus knospenden Zellen bestehen und denen die charakteristische Filamentstruktur des Exophiala-Synanamorphen fehlt.

Exopolysaccharides and capsules in human pathogenic Exophiala species.

Summary. The black yeasts Exophiala spinifera and E. dermatitidis produce extracellular slimes, which may be either in the form of a well-delimited capsule or of diffusely exuded exopolysaccharides (EPS). The optimal conditions for their production were studied. The presence or absence of polysaccharide material can be used for recognition of the two species. Five-day-old cultures grown on potato glucose agar at 24 � C were observed in India ink, and positive identification for E. spinifera was obtained when significant halos were seen around yeast cells. In contrast, E. dermatitidis had irregular EPS with a fibrillar substructure made visible by alcian blue staining. Other Exophiala species produce insignificant amounts of extracellular mucus or none at all. The diagnostic method is particularly useful with yeast-like primary cultures, which often consist entirely of budding cells and lack the characteristic structures of the filamentous Exophiala synanamorph.

Exopolysaccharides and capsules in human pathogenic Exophiala species Exopolysaccharide und Kapseln bei humanpathogenen Exophiala-Arten

Forty seven strains of the black yeasts, Aureobasidium pullulans and Hormonema dematioides, and the type strain of Hormonema macrosporum were examined using PCR-ribotyping and universally primed PCR with subsequent hybridization. Four groups (populations) were distinguished within A. pullulans with PCR-ribotyping, which largely coincided with UP-PCR/hybridization groups. The UP-PCR technique revealed a greater degree of heterogeneity between the groups studied. Five strains identified as Hormonena dematioides on the basis of physiological and morphological data formed a group recognizable with PCR-ribotyping and UP-PCR/hybridization, which also included H. macrosporum. Aureobasidium pullulans is characterized by the absence of RsaI restriction sites in rDNA amplified with primers 5.8S-R and LR7, while Hormonema species possessed several bands after RsaI digestion. For analysis of distance between populations, PCR-ribotyping with AluI and MspI is sufficient. Strains of A. pullulans produce exopolysaccharides in liquid media with different nitrogen sources, while the strains of Hormonema synthesize minor amounts of polysaccharides in media with peptone. Populations of A. pullulans differ slightly from each other in their optimal, medium-dependent production of polysaccharides.

N. A. Yurlova

Papers

Conidiogenesis, nutritional physiology and taxonomy of Aureobasidium and Hormonema.

A new variety of Aureobasidium pullulans characterized by exopolysaccharide structure, nutritional physiology and molecular features

Exopolysaccharides and capsules in human pathogenic Exophiala species.

Exopolysaccharides and capsules in human pathogenic Exophiala species Exopolysaccharide und Kapseln bei humanpathogenen Exophiala-Arten

Intraspecific variability and exopolysaccharide production in Aureobasidium pullulans.