Determination of the reference genes for qRT-PCR normalization and expression levels of MAT genes under various conditions in Ulocladium

The genus Ulocladium is thought to be strictly asexual. One of the possible reasons for the lack of sexuality in Ulocladium species is the absence of the stimulus of environmental factors. Sexual reproduction in ascomycetes is controlled by a specific region in the genome referred to as mating-type locus (MAT) that consists of two dissimilar DNA sequences in the mating partners, termed MAT1-1 and MAT1-2 idiomorphs. To identify the response of MAT loci to environmental conditions, the mRNA transcription level of MAT1-1-1 and MAT1-2-1 genes was tested using qRT-PCR under different temperatures (−20 °C, −10 °C, 0 °C, 10 °C, 20 °C, 30 °C and 40 °C), culture medias (CM, OA, HAY, PCA, PDA and V8), photoperiods (24 h light, 24 h dark, 12 h light/12 h dark, 10 h light/14 h dark and 8 h light/16 h dark), and CO₂ concentrations (0.03%, 0.5%, 1%, 5%, 10%, 15% and 20%). For obtaining reliable results from qRT-PCR, the most stable internal control gene and optimal number of reference genes for normalization were determined under different treatments. The results showed that there is no universal internal control gene that is expressed at a constant level under different experimental treatments. In comparison to various incubation conditions, the relative expression levels of both MAT genes were significantly increased when fungal mycelia were grown on HAY culture media at 0–10 °C with a light/dark cycle, indicating that temperature, culture media, and light might be the key environmental factors for regulating the sexuality in Ulocladium. Moreover, MAT1-1-1 and MAT1-2-1 genes showed similar expression patterns under different treatments, suggesting that the two MAT genes might play an equally important role in the sexual evolutionary process.

Causative fungi and treatment outcome of dematiaceous fungal keratitis in North India

Purpose

The aim of the study is to identify risk factors, clinical characteristics, causative fungi, and treatment outcome of dematiaceous fungal keratitis in North India.

Methods

Consecutive cases of culture-proven dematiaceous fungal keratitis between January 2012 and June 2017 were retrieved from the medical record department. Risk factors, clinical signs, and outcome were registered.

Results

Eighty-three patients were included. Identified dematiaceous fungal organism were Curvularia sp. (n = 55/83; 66.3%), Alternaria sp. (n = 12/83; 14.5%), Ulocladium sp. (n = 5/83; 6%), Bipolaris sp. (n = 5/83; 6.1%), Scedosporium sp. (n = 3/83; 3.6%), Acremonium sp. (n = 2/83; 2.4%), and Epicoccum sp. (n = 1/83; 1.2%). Male preponderance was reported. The most common predisposing factor was corneal trauma (67.4%). In cases associated with corneal trauma due to vegetative matter, sugarcane was the most common cause. In all, 89% of the patients were more than 30 years of age. The median infiltrate size was 8 mm². The median time of antifungal therapy was 4.2 weeks (interquartile range [IQR]: 1-25 weeks). Complications were seen in 14 (n = 14/65; 21.5%) patients. Complete resolution of dematiaceous fungal keratitis was present in 27 (n = 27/65; 41.5%) eyes.

Conclusion

Curvularia sp. and Alternaria sp. were the predominant pathogenic genera causing dematiaceous fungal keratitis. Among the causative fungi, infections due to Scedosporium sp. were associated with the worst outcomes. Ulocladium sp. and Epicoccum sp. were also identified. Both the species are not reported previously as a causal organism of dematiaceous fungal keratitis from North India.

Characterization and phylogenetic analysis of the mating-type loci in the asexual ascomycete genus Ulocladium

The genus Ulocladium is thought to be strictly asexual. Mating-type (MAT) loci regulate sexual reproduction in fungi and their study may help to explain the apparent lack of sexual reproduction in Ulocladium. We sequenced the full length of two MAT genes in 26 Ulocladium species and characterized the entire MAT idiomorphs plus flanking regions of Ulocladium botrytis. The MAT1-1 ORF encodes a protein with an alpha-box motif by the MAT1-1-1 gene and the MAT1-2 ORF encodes a protein with an HMG box motif by the MAT1-2-1 gene. Both MAT1-1-1 and MAT1-2-1 genes were detected in a single strain of every species. Moreover, the results of RT-PCR revealed that both MAT genes are expressed in all 26 Ulocladium species. This demonstrates that MAT genes of Ulocladium species might be functional and that they have the potential for sexual reproduction. Phylogenies based on MAT genes were compared with GAPDH and Alt a 1 phylograms in Ulocladium using maximum parsimony (MP) and Bayesian analysis. The MAT genealogies and the non-MAT trees displayed different topologies, indicating that MAT genes are unsuitable phylogenetic markers at the species level in Ulocladium. Furthermore, the conflicting topologies between MAT1-1-1 and MAT1-2-1 phylogeny indicate separate evolutionary events for the two MAT genes. However, the intergeneric phylogeny of four closely allied genera (Ulocladium, Alternaria, Cochliobolus, Stemphylium) based on MAT alignments demonstrated that MAT genes are suitable for phylogenetic analysis among allied genera.

Alternaria redefined

Alternaria is a ubiquitous fungal genus that includes saprobic, endophytic and pathogenic species associated with a wide variety of substrates. In recent years, DNA-based studies revealed multiple non-monophyletic genera within the Alternaria complex, and Alternaria species clades that do not always correlate to species-groups based on morphological characteristics. The Alternaria complex currently comprises nine genera and eight Alternaria sections. The aim of this study was to delineate phylogenetic lineages within Alternaria and allied genera based on nucleotide sequence data of parts of the 18S nrDNA, 28S nrDNA, ITS, GAPDH, RPB2 and TEF1-alpha gene regions. Our data reveal a Pleospora/Stemphylium clade sister to Embellisia annulata, and a well-supported Alternaria clade. The Alternaria clade contains 24 internal clades and six monotypic lineages, the assemblage of which we recognise as Alternaria. This puts the genera Allewia, Brachycladium, Chalastospora, Chmelia, Crivellia, Embellisia, Lewia, Nimbya, Sinomyces, Teretispora, Ulocladium, Undifilum and Ybotromyces in synonymy with Alternaria. In this study, we treat the 24 internal clades in the Alternaria complex as sections, which is a continuation of a recent proposal for the taxonomic treatment of lineages in Alternaria. Embellisia annulata is synonymised with Dendryphiella salina, and together with Dendryphiella arenariae, are placed in the new genus Paradendryphiella. The sexual genera Clathrospora and Comoclathris, which were previously associated with Alternaria, cluster within the Pleosporaceae, outside Alternaria s. str., whereas Alternariaster, a genus formerly seen as part of Alternaria, clusters within the Leptosphaeriaceae. Paradendryphiella is newly described, the generic circumscription of Alternaria is emended, and 32 new combinations and 10 new names are proposed. A further 10 names are resurrected, while descriptions are provided for 16 new Alternaria sections.

Indoor airborne mold spores in newly built dwellings

OBJECTIVE

To investigate the relationships between sick building syndrome and mold in newly-built dwellings.

METHODS

Symptoms of 61 residents in 18 dwellings were surveyed by standardized questionnaires. Mold sampling was done by gravity sampling using an open Petri dish. Potato dextrose agar (PDA) and dichloran-18% glycerol agar (DG-18) were used as the culture medium.

RESULTS

There were 6 dwellings in which at least one inhabitant complained of one or more symptoms and 12 dwellings in which none of the inhabitants complained of symptoms. There was a tendency for the dwellings with inhabitants reporting symptoms to have larger colony forming units (CFU) on PDA than those without inhabitants reporting symptoms (p=0.1), but there was no difference in DG-18 result. There was a tendency for the dwellings with inhabitants reporting symptoms to have larger CFU ofCladosporium on PDA than those without (p=0.08), but there was no difference in DG-18 result. Significantly moreUlocladium sp. was detected in the dwellings with inhabitants reporting symptoms than in those without (p=0.03).Cladosporium cladosporioides was detected in all the dwellings with inhabitants reporting symptoms and 75% of the dwellings without.Cladosporium macrocarpum andCladosporium herbarum were detected in 33% of the dwellings with inhabitants reporting e symptoms and none of the dwellings without (p=0.1).

CONCLUSION

Cladosporium was dominant in the Japanese newly-built dwellings studied, andCladosporium andUlocladium were probably associated with the residents' symptoms in these newly-built dwellings.

An unusual phaeoid fungi: Ulocladium, as a cause of chronic allergic fungal sinusitis

Allergic fungal sinusitis (AFS) has been recognized as an important cause of chronic sinusitis commonly caused by Aspergillus spp. and various dematiaceous fungi like Bipolaris, Alternaria, Curvalaria, and etc. Ulocladium botrytis is a non pathogenic environmental dematiaceous fungi, which has been recently described as a human pathogen. Ulocladium has never been associated with allergic fungal sinusitis but it was identified as an etiological agent of AFS in a 35 year old immunocompetent female patient presenting with chronic nasal obstruction of several months duration to our hospital. The patient underwent FESS and the excised polyps revealed Ulocladium as the causative fungal agent.