Burden of fungal disease in Ireland

Our objective was to estimate the burden of fungal disease on the island of Ireland, as part of a coordinated project estimating the global burden. Published epidemiology data describing fungal infection in Ireland were identified. Population and underlying disease data were collected for 2010 and a structured set of assumptions were applied to estimate burden of fungal disease based on immunosuppression, chronic disease, and other demographic information indicating predisposition to fungal infection. From Ireland’s population of 6.4 million, we estimate 117 000 patients develop significant fungal disease each year. By far the most common fungal disease is recurrent Candida vaginitis, with an estimated 95 000 episodes annually (3000 per 100 000 women). Other fungal diseases which may be less well recognized are severe asthma with fungal sensitization and allergic bronchopulmonary aspergillosis, with estimated episodes per year of 11 700 and 9000, respectively (182 and 140 per 100 000 population, respectively). The model also estimates 450 episodes of invasive aspergillosis, 200 of chronic pulmonary aspergillosis, 600 of oesophageal candidiasis and 450 of candidaemia per year (7, 3, 9 and 6 episodes per 100 000 population, respectively). This is, we believe, the first attempt to estimate the burden of fungal disease in our population and provides a basis for estimating its impact on human health and resource use.

Fungal stress biology: A preface to the Fungal Stress Responses special edition

There is currently an urgent need to increase global food security, reverse the trends of increasing cancer rates, protect environmental health, and mitigate climate change. Toward these ends, it is imperative to improve soil health and crop productivity, reduce food spoilage, reduce pesticide usage by increasing the use of biological control, optimize bioremediation of polluted sites, and generate energy from sustainable sources such as biofuels. This review focuses on fungi that can help provide solutions to such problems. We discuss key aspects of fungal stress biology in the context of the papers published in this Special Issue of Current Genetics. This area of biology has relevance to pure and applied research on fungal (and indeed other) systems, including biological control of insect pests, roles of saprotrophic fungi in agriculture and forestry, mycotoxin contamination of the food-supply chain, optimization of microbial fermentations including those used for bioethanol production, plant pathology, the limits of life on Earth, and astrobiology.

The International Symposium on Fungal Stress - ISFUS

Fungi play central roles in many biological processes, influencing soil fertility, decomposition, cycling of minerals, and organic matter, plant health, and nutrition. They produce a wide spectrum of molecules, which are exploited in a range of industrial processes to manufacture foods, food preservatives, flavoring agents, and other useful biological products. Fungi can also be used as biological control agents of microbial pathogens, nematodes or insect pests, and affect plant growth, stress tolerance, and nutrient acquisition. Successful exploitation of fungi requires better understanding of the mechanisms that fungi use to cope with stress as well as the way in which they mediate stress tolerance in other organisms. It is against this backdrop that a scientific meeting on fungal stress was held in São José dos Campos, Brazil, in October 2014. The meeting, hosted by Drauzio E. N. Rangel and Alene E. Alder-Rangel, and supported by the São Paulo Research Foundation (FAPESP), brought together more than 30 young, mid-career, and highly accomplished scientists from ten different countries. Here we summarize the highlights of the meeting.

Genetic diversity of root-associated fungal endophytes from Calluna vulgaris at contrasting field sites

A total of 107 putative ericoid mycorrhizal endophytes were isolated from hair roots of Calluna vulgaris from two abandoned arsenic/copper mine sites and a natural heathland site in southwest England. The endophytes were initially grouped as 14 RFLP types, based on the results of ITS-RFLP analysis using the restriction endonucleases Hinf I, Rsa I and Hae III. ITS sequences were obtained for representative isolates from each RFLP type and compared phylogenetically with sequences for known ericoid mycorrhizal endophytes and selected ascomycetes. The majority of endophyte isolates (62-92%) from each site were identified as Hymenoscyphus ericae, but a number of other less common mycorrhizal RFLP types were also identified, all of which appear to have strong affinities with the order Leotiales. None of the less common RFLP types was isolated from C. vulgaris at more than one field site. Neighbour-joining analysis indicated similarities between the endophytes from C. vulgaris and mycorrhizal endophytes isolated from other Ericaceae and Epacridaceae hosts in North America and Australia.

Assessment of toxicological interactions of benzene and its primary degradation products (catechol and phenol) using a lux-modified bacterial bioassay

A bacterial bioassay has been developed to assess the relative toxicities of xenobiotics commonly found in contaminated soils, rivers, waters, and ground waters. The assay utilized decline in luminescence of lux- marked Pseudomonas fluorescens on exposure to xenobiotics. Pseudomonas fluorescens is a common bacterium in the terrestrial environment, providing environmental relevance to soil, river, and ground water systems. Three principal environmental contaminants associated with benzene degradation were exposed to the luminescence-marked bacterial biosensor to assess their toxicity individually and in combination. Median effective concentration (EC50) values for decline in luminescence were determined for benzene, catechol, and phenol and were found to be 39.9, 0.77, and 458.6 mg/L, respectively. Catechol, a fungal and bacterial metabolite of benzene, was found to be significantly more toxic to the biosensor than was the parent compound benzene, showing that products of xenobiotic biodegradation may be more toxic than the parent compounds. Combinations of parent compounds and metabolites were found to be significantly more toxic to the bioassay than were the individual compounds themselves. Development of this bioassay has provided a rapid screening system suitable for assessing the toxicity of xenobiotics commonly found in contaminated soil, river, and ground-water environments. The assay can be utilized over a wide pH range and is therefore more applicable to such environmental systems than bioluminescence-based bioassays that utilize marine organisms and can only be applied over a limited pH and salinity range.

Biocontrol agents promote growth of potato pathogens, depending on environmental conditions

There is a pressing need to understand and optimize biological control so as to avoid over-reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol-strain, Bacillus sp. JC12GB43, and potato-pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near-complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out-perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth-rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2-M glycerol) by up to 570%. Culture-based assays involving macromolecule-stabilizing (kosmotropic) compatible solutes provided proof-of-principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.

Enzyme-catalysed oxidation of 1,2-disulfides to yield chiral thiosulfinate, sulfoxide and cis-dihydrodiol metabolites

Enantioenriched and enantiopure thiosulfinates were obtained by asymmetric sulfoxidation of cyclic 1,2-disulfides, using chemical and enzymatic (peroxidase, monooxygenase, dioxygenase) oxidation methods and chiral stationary phase HPLC resolution of racemic thiosulfinates. Enantiomeric excess values, absolute configurations and configurational stabilities of chiral thiosulfinates were determined. Methyl phenyl sulfoxide, benzo[c]thiophene cis-4,5-dihydrodiol and 1,3-dihydrobenzo[c]thiophene derivatives were among unexpected types of metabolites isolated, when acyclic and cyclic 1,2-disulfide were used as substrates for Pseudomonas putida strains. Possible biosynthetic pathways are presented for the production of metabolites from 1,4-dihydrobenzo-2,3-dithiane, including a novel cis-dihydrodiol metabolite that was also derived from benzo[c]thiophene and 1,3-dihydrobenzo[c]thiophene.

Arbuscular mycorrhizal fungal hyphae reduce soil erosion by surface water flow in a greenhouse experiment

The role of arbuscular mycorrhizal fungi (AMF) in resisting surface flow soil erosion has never been tested experimentally. We set up a full factorial greenhouse experiment using Achillea millefolium with treatments consisting of addition of AMF inoculum and non-microbial filtrate, non-AMF inoculum and microbial filtrate, AMF inoculum and microbial filtrate, and non-AMF inoculum and non-microbial filtrate (control) which were subjected to a constant shear stress in the form of surface water flow to quantify the soil detachment rate through time. We found that soil loss can be explained by the combined effect of roots and AMF extraradical hyphae and we could disentangle the unique effect of AMF hyphal length, which significantly reduced soil loss, highlighting their potential importance in riparian systems.

Patterns of Behaviour, Group Structure and Reproductive Status Predict Levels of Glucocorticoid Metabolites in Zoo-Housed Ring-Tailed Lemurs, Lemur catta

In ring-tailed lemurs, Lemur catta, the factors modulating hypothalamic-pituitaryadrenal (HPA) activity differ between wild and semi-free-ranging populations. Here we assess factors modulating HPA activity in ring-tailed lemurs housed in a third environment: the zoo. First we validate an enzyme immunoassay to quantify levels of glucocorticoid (GC) metabolites in the faeces of L. catta . We determine the nature of the femalefemale dominance hierarchies within each group by computing David's scores and examining these in relation to faecal GC (fGC). Relationships between female age and fGC are assessed to evaluate potential age-related confounds. The associations between fGC, numbers of males in a group and reproductive status are explored. Finally, we investigate the value of 7 behaviours in predicting levels of fGC. The study revealed stable linear dominance hierarchies in females within each group. The number of males in a social group together with reproductive status, but not age, influenced fGC. The 7 behavioural variables accounted for 68% of the variance in fGC. The amounts of time an animal spent locomoting and in the inside enclosure were both negative predictors of fGC. The study highlights the flexibility and adaptability of the HPA system in ring-tailed lemurs.