Aspergillus penicillioides—a true halophile existing in hypersaline and polyhaline econiches

Nazareth, S.W.; Gonsalves, Valerie

doi:10.1007/s13213-013-0646-5

Cited by 29 publications

(21 citation statements)

References 13 publications

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“…2000 ), including members of sect. Restricti ( Cantrell et al., 2006 , Nazareth and Gonsalves, 2014 ). The novel species A. salinicola described in this study is a saltern inhabitant ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Phylogeny of xerophilic aspergilli (subgenus Aspergillus) and taxonomic revision of section Restricti

Sklenář¹,

Jurjević²,

Zalar³

et al. 2017

Studies in Mycology

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Aspergillus section Restricti together with sister section Aspergillus (formerly Eurotium) comprises xerophilic species, that are able to grow on substrates with low water activity and in extreme environments. We adressed the monophyly of both sections within subgenus Aspergillus and applied a multidisciplinary approach for definition of species boundaries in sect. Restricti. The monophyly of sections Aspergillus and Restricti was tested on a set of 102 isolates comprising all currently accepted species and was strongly supported by Maximum likelihood (ML) and Bayesian inferrence (BI) analysis based on β-tubulin (benA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) loci. More than 300 strains belonging to sect. Restricti from various isolation sources and four continents were characterized by DNA sequencing, and 193 isolates were selected for phylogenetic analyses and phenotypic studies. Species delimitation methods based on multispecies coalescent model were employed on DNA sequences from four loci, i.e., ID region of rDNA (ITS + 28S), CaM, benA and RPB2, and supported recognition of 21 species, including 14 new. All these species were also strongly supported in ML and BI analyses. All recognised species can be reliably identified by all four examined genetic loci. Phenotype analysis was performed to support the delimitation of new species and includes colony characteristics on seven cultivation media incubated at several temperatures, growth on an osmotic gradient (six media with NaCl concentration from 0 to 25 %) and analysis of morphology including scanning electron microscopy. The micromorphology of conidial heads, vesicle dimensions, temperature profiles and growth parameters in osmotic gradient were useful criteria for species identification.The vast majority of species in sect. Restricti produce asperglaucide, asperphenamate or both in contrast to species in sect. Aspergillus. Mycophenolic acid was detected for the first time in at least six members of the section. The ascomata of A. halophilicus do not contain auroglaucin, epiheveadride or flavoglaucin which are common in sect. Aspergillus, but shares the echinulins with sect. Aspergillus.

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Section: Discussionmentioning

confidence: 99%

Phylogeny of xerophilic aspergilli (subgenus Aspergillus) and taxonomic revision of section Restricti

Sklenář¹,

Jurjević²,

Zalar³

et al. 2017

Studies in Mycology

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“…This species, sometimes implicated in aspergillosis (Gupta et al, 2015;Paulussen et al, in press), has also been the focus of studies on production of secondary metabolites, ecology of hypersaline environments, food spoilage, damage to cultural artefacts and coal-mine bioaerosols (Zhao et al, 2014;Nazareth and Gonsalves, 2014;Okano et al, 2015;Wei et al, 2015;Micheluz et al, 2016). A. penicillioides is at the same time xerophilic, osmophilic and halophilic (in relation to low water activity, high sugar-and NaCl concentrations, respectively), grows close to 08C (and almost certainly at sub-zero temperatures, as well) and can function anaerobically (Chin et al, 2010;Zhang et al, 2013;Nazareth and Gonsalves, 2014;Rummel et al, 2014). When growing in saline conditions, xerophilic aspergilli synthesize and accumulate molar concentrations of glycerol at low wateractivity (Nazareth and Gonsalves, 2014;de Lima Alves et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…A. penicillioides is at the same time xerophilic, osmophilic and halophilic (in relation to low water activity, high sugar-and NaCl concentrations, respectively), grows close to 08C (and almost certainly at sub-zero temperatures, as well) and can function anaerobically (Chin et al, 2010;Zhang et al, 2013;Nazareth and Gonsalves, 2014;Rummel et al, 2014). When growing in saline conditions, xerophilic aspergilli synthesize and accumulate molar concentrations of glycerol at low wateractivity (Nazareth and Gonsalves, 2014;de Lima Alves et al, 2015). Brines which existed in early Mars (and likely also present-day on Mars and other planetary bodies) have a peculiar composition and chemistry, and their exceptional high ionic strength can be the life-limiting parameter in relation to their habitability with terrestrial microbes (Tosca et al, 2011;Fox-Powell et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Aspergillus penicillioides differentiation and cell division at 0.585 water activity

Stevenson

Hamill

O'Kane

et al. 2017

Environmental Microbiology

111

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SummaryWater availability acts as the most stringent constraint for life on Earth. Thus, understanding the water relations of microbial extremophiles is imperative to our ability to increase agricultural productivity (e.g., by enhancing the processing and turnover of dead organic matter in soils of arid regions), reduce human exposure to mycotoxins in buildings and our foodsupply chain, prevent the spoilage of foods/animal feeds, books, museum specimens and artworks and better control microbiology of industrial fermentations. Only a small number of microbial systems can retain activity at <0.710 water activity (ISME J 2015 9: 1333-1351). It has long-been considered that the most resilient of these is Xeromyces bisporus, which inhabits sugar-rich substrates (Appl Environ Microbiol 1968 16: 1853-1858. The current study focused on germination of Aspergillus penicillioides, a xerophile which is also able to grow under low humidity and saline conditions. Investigations of germination differed from those reported earlier: firstly, aerially borne conidia were harvested, and then used for inoculations, in their dry condition; secondly, cultures were incubated at 248C, i.e. below optimum germination temperature, to minimize the possibility of water loss from the substrate; thirdly, cultures remained sealed throughout the 73-day study period (microscopic examination was carried out directly 48 through the Petri plate lid); fourthly, the germination parameters determined were: rates and extent of conidial swelling, production of differentiated germinationstructures and septate germlings, and subsequent development of mycelium and/or sporulation; fifthly, assessments were carried out over a range of wateractivity values and time points to obtain a complete profile of the germination process. Conidia swelled, formed differentiated germination-structures and then produced septate germlings at a water-activity of just 0.585 (58.5% relative humidity), outside the currently understood thermodynamic window for life. Furthermore, analyses of these data suggest a theoretical water-activity minimum of 0.565 for germination of A. penicilliodes. In relation to astrobiology, these findings have an application in understanding the limits to life in extraterrestrial environments. In light of current plans for exploration missions to Mars and other places, and the need to safeguard martian scientific sites and potential resources (including water) for future human habitation, a knowledge-based and effective policy for planetary protection is essential. As it is, Mars-bound spacecraft may frequently be contaminated with aspergilli (including A. penicillioides) and other organisms which, when transported to other planetary bodies, pose a contamination risk. In crafting countermeasures to offset this, it is important to know as precisely as possible the capabilities of these potential interplanetary visitors.

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“…Aspergillus spp. and Saccharomyces cerevisiae synthesize and accumulate compatible solutes, such as glycerol, to protect proteins and nucleic acids (9)(10)(11). Due to the lack of water Xeromyces bisporus and some other food-borne molds have increased amount of saturated fatty acid in their membrane, and form extracellular polymers (12).…”

Section: Introductionmentioning

confidence: 99%

Transcriptional response of Bacillus megaterium FDU301 to PEG200-mediated arid stress

Zhao

Zhou

et al. 2020

Preprint

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Background For the microorganisms on the paper surface, the lack of water is one of the most important stress factors. A strain of Bacillus megaterium FDU301 was isolated from plaques on the paper surface using the culture medium with polyethylene glycol 200 (PEG200) to simulate arid condition. Global transcriptomic analysis of B. megaterium FDU301 grown under normal and the simulated arid conditions was performed via RNA-seq technology to identify genes involved in arid stress adaptation. Results The transcriptome of B. megaterium FDU301 grown in LB medium under arid (15% PEG200 (w/w)) and normal conditions were compared. A total of 2941 genes were differentially expressed, including 1422 genes up-regulated and 1519 genes down-regulated under arid conditions. Oxidative stress-responsive regulatory genes perR, fur, and tipA were significantly up-regulated, along with DNA protecting protein (dps), catalase (katE). Genes related to Fe2+ uptake (feoB), spore formation stage II (spoIIB, spoIIE, spoIIGA), small acid-soluble spore protein (sspD), and biosynthesis of compatible solute ectoine (ectB, ectA) were also highly expressed to various degrees. Meanwhile, oxidative phosphorylation-related genes (atpB, atpE, atpF, atpH, atpA, atpG, atpD, atpC) and glycolysis-related genes (pgk, tpiA, frmA) were significantly down-regulated. Conclusion This is the first report about transcriptomic analysis of a B. megaterium to explore the mechanism of arid resistance. Major changes in transcription were seen in the arid condition simulated by PEG200 (15%), with the most important one being the genes related to oxidative stress. The results showed the complex mechanism for bacteria to adapt to arid stress.

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Aspergillus penicillioides—a true halophile existing in hypersaline and polyhaline econiches

Cited by 29 publications

References 13 publications

Phylogeny of xerophilic aspergilli (subgenus Aspergillus) and taxonomic revision of section Restricti

Phylogeny of xerophilic aspergilli (subgenus Aspergillus) and taxonomic revision of section Restricti

Aspergillus penicillioides differentiation and cell division at 0.585 water activity

Transcriptional response of Bacillus megaterium FDU301 to PEG200-mediated arid stress

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