Nomenclatural issues concerning cultured yeasts and other fungi: why it is important to avoid unneeded name changes

The unambiguous application of fungal names is important to communicate scientific findings. Names are critical for (clinical) diagnostics, legal compliance, and regulatory controls, such as biosafety, food security, quarantine regulations, and industrial applications. Consequently, the stability of the taxonomic system and the traceability of nomenclatural changes is crucial for a broad range of users and taxonomists. The unambiguous application of names is assured by the preservation of nomenclatural history and the physical organisms representing a name. Fungi are extremely diverse in terms of ecology, lifestyle, and methods of study. Predominantly unicellular fungi known as yeasts are usually investigated as living cultures. Methods to characterize yeasts include physiological (growth) tests and experiments to induce a sexual morph; both methods require viable cultures. Thus, the preservation and availability of viable reference cultures are important, and cultures representing reference material are cited in species descriptions. Historical surveys revealed drawbacks and inconsistencies between past practices and modern requirements as stated in the International Code of Nomenclature for Algae, Fungi, and Plants (ICNafp). Improper typification of yeasts is a common problem, resulting in a large number invalid yeast species names. With this opinion letter, we address the problem that culturable microorganisms, notably some fungi and algae, require specific provisions under the ICNafp. We use yeasts as a prominent example of fungi known from cultures. But viable type material is important not only for yeasts, but also for other cultivable Fungi that are characterized by particular morphological structures (a specific type of spores), growth properties, and secondary metabolites. We summarize potential proposals which, in our opinion, will improve the stability of fungal names, in particular by protecting those names for which the reference material can be traced back to the original isolate

Species Accumulation Curves and Incidence-Based Species Richness Estimators to Appraise the Diversity of Cultivable Yeasts from Beech Forest Soils

Background: Yeast-like fungi inhabit soils throughout all climatic zones in a great abundance. While recent estimations predicted a plethora of prokaryotic taxa in one gram of soil, similar data are lacking for fungi, especially yeasts. Methodology/Principal Findings: We assessed the diversity of soil yeasts in different forests of central Germany using cultivation-based techniques with subsequent identification based on rDNA sequence data. Based on experiments using various pre-cultivation sample treatment and different cultivation media we obtained the highest number of yeasts by analysing mixed soil samples with a single nutrient-rich medium. Additionally, several species richness estimators were applied to incidence-based data of 165 samples. All of them predicted a similar range of yeast diversity, namely 14 to 16 species. Randomized species richness curves reached saturation in all applied estimators, thus indicating that the majority of species is detected after approximately 30 to 50 samples analysed. Conclusions/Significance: In this study we demonstrate that robust species identification as well as mathematical approaches are essential to reliably estimate the sampling effort needed to describe soil yeast communities. This approach has great potential for optimisation of cultivation techniques and allows high throughput analysis in the future

Review of the gross anatomy and microbiology of the Phasmatodea digestive tract

The sparse descriptions of the stick insect (Phasmatodea) digestive system as reported/provided in the literature are highly contradictory. This paper describes the digestive systems of several families of Phasmatodea (Timematidae, Heteropterygidae, Diapheromeridae, Pseudophasmatidae, and Phasmatidae) plus the gut microbiome of these and one other (Phylliidae) to both verify past findings and provide a general description of the Phasmatodea alimentary canal. The constrictions imposed by this anatomy on phasmid gut microbiology, its connections to recently released Phasmatodea transcriptomes, and how it differs from the anatomy of related orders in the Polyneoptera are discussed. All Phasmatodea have ridged proventriculi lined or covered with small spines. Anterior projections of the midgut, sometimes described as gastric caeca, are only found in Euphasmatodea and often obscure the proventriculus. We define the cardia as the complex of foregut and midgut tissue where the type II peritrophic matrix is produced. Appendices of the midgut are an autapomorphy for Phasmatodea, but Timema have fewer and larger appendices relative to body size. We suggest caeca-like projections and the loss of large, proventricular teeth are apomorphies of Euphasmatodea. We identify a possible facultative symbiosis in Eucalyptus-feeding species that requires further study

Indonesian oleaginous yeasts isolated from Piper betle and P. nigrum

Abstract In this study, 71 strains of yeast were isolated from Piper betle and P. nigrum. Isolates were identified using sequence analysis of the D1/D2 region of large 26S ribosomal subunit rDNA. They belong to 25 species in 11 genera. Strains Cryptococcus luteolus InaCC Y-265, Candida orthopsilosis InaCC Y-302, and Candida oleophila InaCC Y-306 could accumulate more than 40% of lipid per g of cell biomass on a dry weight basis. The fatty acids observed were primarily palmitic acid (C18:1), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1) and linolenic acid (C18:2). The fatty acid profiles suggest that these yeasts may be good candidates for biodiesel production, as they are similar to the fatty acids of plant oils currently used for biodiesel

Preserving US microbe collections sparks future discoveries

Collections of micro-organisms are a crucial element of life science research infrastructure but are vulnerable to loss and damage caused by natural or man-made disasters, the untimely death or retirement of personnel, or the loss of research funding. Preservation of biological collections has risen in priority due to a new appreciation for discoveries linked to preserved specimens, emerging hurdles to international collecting and decreased funding for new collecting. While many historic collections have been lost, several have been preserved, some with dramatic rescue stories. Rescued microbes have been used for discoveries in areas of health, biotechnology and basic life science. Suggestions for long-term planning for microbial stocks are listed, as well as inducements for long-term preservation