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Peptidyl-prolyl cis–trans isomerases (PPIases) are the only class of enzymes capable of cis–trans isomerization of the prolyl peptide bond. The PPIases, comprising of different families viz., cyclophilins, FK506-binding proteins (FKBPs), parvulins and protein phosphatase 2A phosphatase activators (PTPAs), play essential roles in different cellular processes. Though PPIase gene families have been characterized in different organisms, information regarding these proteins is lacking in Penicillium species, which are commercially an important fungi group. In this study, we carried out genome-wide analysis of PPIases in different Penicillium spp. and investigated their regulation by salt stress in a halotolerant strain of Penicillium oxalicum. These analyses revealed that the number of genes encoding cyclophilins, FKBPs, parvulins and PTPAs in Penicillium spp. varies between 7–11, 2–5, 1–2, and 1–2, respectively. The halotolerant P. oxalicum depicted significant enhancement in the mycelial PPIase activity in the presence of 15% NaCl, thus, highlighting the role of these enzymes in salt stress adaptation. The stress-induced increase in PPIase activity at 4 and 10 DAI in P. oxalicum was associated with higher expression of PoxCYP18. Characterization of PPIases in Penicillium spp. will provide an important database for understanding their cellular functions and might facilitate their applications in industrial processes through biotechnological interventions. [ABSTRACT FROM AUTHOR]

S. kudriavzevii has potential for fermentations and other biotechnological applications, but is sensitive to many types of stress. We tried to increase its tolerance and performance via the expression of various transporters from different yeast species. Whereas the overexpression of Z. rouxii fructose uptake systems ( Zr Ffz1 and Zr Fsy1) or a glycerol importer ( Zr Stl1) did not improve the ability of S. kudriavzevii to consume fructose and survive osmotic stress, the expression of alkali-metal-cation exporters ( Sc Ena1, Sc Nha1, Yl Nha2) improved S. kudriavzevii salt tolerance, and that of Sc Nha1 also the fermentation performance. The level of improvement depended on the type and activity of the transporter suggesting that the natural sensitivity of S. kudriavzevii cells to salts is based on a non-optimal functioning of its own transporters. [ABSTRACT FROM AUTHOR]

Characterization of the changes after various stimuli is crucial to comprehend the adaptation of cells to the changing condition. Aspergillus oryzae is widely used for the industrial production of soy sauce, which always encounter changes within a complex environment, such as salinity stress. However, the protective biochemical mechanisms of A. oryzae against salinity stress are poorly understood. In this study, we successfully characterized the fermentative behavior, transcriptomic profiles, and metabolite changes of A. oryzae in response to salinity stress. The results showed that salt treatment of A. oryzae inhibited the fungal development and conidia formation. Transcriptomic analysis showed an upregulated expression of the genes related to arginine accumulation and oleic acid synthesis. The results of qRT-PCR were further confirmed by the reliability and availability of the differentially expressed genes obtained from the transcriptome analysis. Metabolomic analysis revealed that the corresponding intracellular accumulation of arginine and oleic acid were also increased in response to the salinity stress. All of the results provide a global transcriptome characterization of the salt adaptation process in A. oryzae, and offer multiple target genes for salt tolerance improvement via genetic engineering. [ABSTRACT FROM AUTHOR]

Catalytic properties of halophilic exoglucanase from a marine Aspergillus niger and the secondary structure change caused by high salinity was analyzed under high salinities condition. Exoglucanase activity in 12% NaCl solution (w/v) was 1.32 folds higher of that in NaCl free solution. Half-life time in 12% NaCl solution (w/v) was over 1.41 folds higher of that in NaCl free solution. The exoglucanase had not endoglucanase activity. Gibbs free energy change of exoglucanase denaturation, △ G , in 12% NaCl solution (w/v) was about 1.0 kJ/mol more than that in NaCl free solution at 45 °C, 50 °C, 55 °C and 60 °C. Melt temperature in 12% NaCl solution (w/v), 48.02 °C, was 3.32 °C higher than that in NaCl free solution, 44.70 °C. High salinity made contents of β-sheet and α-helix increased. The secondary structure change caused by high salinities improved exoglucanase thermostability and activity. The halostable exoglucanase from a marine Aspergillus niger was valuable for cellulose hydrolysis at high salinities. [ABSTRACT FROM AUTHOR]

Peroxisomes are dynamic organelles and the sole location for fatty acid β-oxidation in yeast cells. Here, we report that peroxisomal function is crucial for the adaptation to salt stress, especially upon sugar limitation. Upon stress, multiple layers of control regulate the activity and the number of peroxisomes. Activated Hog1 MAP kinase triggers the induction of genes encoding enzymes for fatty acid activation, peroxisomal import and β-oxidation through the Adr1 transcriptional activator, which transiently associates with genes encoding fatty acid metabolic enzymes in a stress- and Hog1-dependent manner. Moreover, Na+ and Li+ stress increases the number of peroxisomes per cell in a Hog1-independent manner, which depends instead of the retrograde pathway and the dynamin related GTPases Dnm1 and Vps1. The strong activation of the Faa1 fatty acyl-CoA synthetase, which specifically localizes to lipid particles and peroxisomes, indicates that adaptation to salt stress requires the enhanced mobilization of fatty acids from internal lipid stores. Furthermore, the activation of mitochondrial respiration during stress depends on peroxisomes, mitochondrial acetyl-carnitine uptake is essential for salt resistance and the number of peroxisomes attached to the mitochondrial network increases during salt adaptation, which altogether indicates that stress-induced peroxisomal β-oxidation triggers enhanced respiration upon salt shock. [ABSTRACT FROM AUTHOR]

The Dead Sea is an extremely stressful hypersaline environment and a unique model for tracking evolutionary dynamics of biodiversity under increasing salinity. Dead Sea salinity stress eliminates most life forms except one alga, several species of Archaea, Bacteria, and filamentous fungi. Here we demonstrate, based on both seasonal (winter-summer) and inter-annual (2000-2015) evidence, that the turnover of fungal species diversity in the last 15 years decreased from 34 species in winter 2000 to 2 species in summer 2015. Species diversity steadily decreased and highly and significantly correlated with declining water level as well as increasing density and salinity stress, which is currently 348 gL-1. The two surviving species, Aspergillus amstelodami Thom & Church and Aspergillus ruber Thom & Church, increased in frequency across all sampling sites, down to the Dead Sea bottom (-291 m), due to their evolved adaptations to tolerate hypersalinity. In summer 2015, most previously described fungi were not found except for the two aforementioned halophilic Aspergilli species. However, even the best adapted species to highly increased salinity decreased in frequency in the current extremely climaxing harsh conditions. [ABSTRACT FROM AUTHOR]

The highly conserved family of P hos p hoprotein p hosphatases (PPP) regulates several major physiological processes in yeast. However, very little is known about the PPP orthologs from the yeast species inhabiting extreme environmental niches. In the present study we have identified DhSIT4 , a member of PPP6 class of serine threonine phosphatases from the halotolerant yeast Debaryomyces hansenii . Deletion of DhSIT4 in D . hansenii was not lethal but the mutant exhibited reduced growth due to its effect on the cell cycle. The knock out mutant Dhsit4Δ showed sensitivity towards Li + , Na + and cell wall damaging agents. The expression of DhSit4p rescued salt, caffeine and calcofluor white sensitivity of Dhmpk1Δ strain and thereby indicating a genetic interaction of this phosphatase with the cell wall integrity pathway in this species. Our study also demonstrated the antagonistic roles of DhSit4p and DhPpz1p in maintaining the cell cycle and ion homeostasis in D . hansenii . [ABSTRACT FROM AUTHOR]

Materials and methods: Nine fungal isolates namely Emericill anidulans, Mucor racemosus , Alternaria pluriseptata Penicillium canescens, Syncephalastrum racemosum, Aspergillus fumigatus, Alternaria chlamydospora, Aspergillus parasiticus and Ulocladium atrum were isolated from AL-SHEGA area at AL- QASSIM region. Results: The influence of different sodium chloride concentrations on the growth rate, morphological and ultrastructure were studied. Considerable differences in their growth rate and morphology were detected on medium containing different concentrations of sodium chloride (NaCl). Low growth rates were obseved on high NaCl concentrations . At 15 % NaCl, low growth of Emericill anidulans, Penicillium canescens, Syncephalastrum racemosum, Aspergillus parasiticus and Mucor racemosus was detected , whereas all fungal isolates were failed to grow at 20% NaCl. Scanning Electron Microscope (SEM) revealed that all fungal asexual reproduction organs were metamorphosed at higher NaCl concentration, fungal heads and sporangia were speculated or elongated. Sporangiophores and conidiophores were shortened and dwarfed ,little number of conidia or spores were detected. [ABSTRACT FROM AUTHOR]

Marine environments are unique habitats for microorganisms and represent uninvestigated areas that possess valuable resources. Fungi may also be important because they contribute to marine ecosystems as decomposers. The aims of this study were to investigate the halotolerance of marine-derived fungi and their enzymatic properties. Eighteen fungal strains representing 11 different species were used, which included 17 ascomycetes and a zygomycete. The majority were not affected by salinity and showed endo-glucanase (EG) and ß-glucosidase (BGL) activities. Interestingly, the cellulolytic enzyme activity derived from Penicillium chrysogenum FU42 increased with salinity. To investigate whether this increase was due to an adaptation or an innate ability of the species, P. chrysogenum KCTC6933, which originated from a terrestrial environment, was used as a control, and its enzymatic properties were compared. Consequently, P. chrysogenum FU42, which was derived from the ocean, showed unique enzymatic properties that might enable the fungus to live in the ocean and contribute to the nutrient cycle in marine ecosystems. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae strains tolerant to salt stress are important for the production of single-cell protein using kimchi waste brine. In this study, two strains (TN-1 and TN-2) tolerant of up to 10 % (w/v) NaCl were isolated by screening a transposon-mediated mutant library. The determination of transposon insertion sites and Northern blot analysis identified two genes, MDJ1 and VPS74, and revealed disruptions of the open reading frame of both genes, indicating that salt tolerance can be conferred. Such tolerant phenotypes reverted to sensitive phenotypes on the autologous or overexpression of each gene. The two transposon mutants grew faster than the control strain when cultured at 30 °C in rich medium containing 5, 7.5 or 10 % NaCl. The genes identified in this study may provide a basis for application in developing industrial yeast strains. [ABSTRACT FROM AUTHOR]

As one of the major microbes in the soy sauce fermentation, Candida versatilis enriches the flavor and improves the quality of soy sauce. In this study, a combination of five different GC-MS and LC-MS-based metabolome analytical approaches was used to analyze the intracellular, extracellular and whole metabolites of C. versatilis. Our results found out that a total of 132, 244 and 267 different metabolites were detectable from the intracellular, extracellular and whole part, respectively. When exposed to 0. 9 and 18 % salt, respectively, 114, 123 and 129 different intracellular metabolites, 184, 200 and 178 extracellular metabolites and 177, 188 and 186 whole metabolites were detected, respectively. Our data showed that salt enhances the metabolic capacity of C. versatilis, especially its amino acid and enhances the synthesis and secretion of some metabolites of C. versatilis, especially the aldehydes and phenols, such as vanillin, guaiacol and 5-hydroxymethylfurfural. Our data also showed that special attention has to be paid to the generation of biogenic amines when C. versatilis was treated with salt. [ABSTRACT FROM AUTHOR]

The yeast ubiquitin-like and ubiquitin-associated protein Dsk2 is one of the ubiquitin receptors that function in the ubiquitin-proteasome pathway. We screened the Dsk2-interacting proteins in Saccharomyces cerevisiae by a two-hybrid assay and identified a novel Dsk2-interacting protein, Irc22, the gene locus of which has previously been described as YEL001C, but the function of which is unknown. IRC22/YEL001C encodes 225 amino acid residues with a calculated molecular weight of 25 kDa. The Irc22 protein was detected in yeast cells. IRC22 was a nonessential gene for yeast growth, and its homologs were found among ascomycetous yeasts. Irc22 interacted with Dsk2 in yeast cells, but not with Rad23 and Ddi1. Ubiquitin-dependent degradation was impaired mildly by over-expression or disruption of IRC22. Compared with the wild-type strain, dsk2Δ exhibited salt sensitivity while irc22Δ exhibited salt tolerance at high temperatures. The salt-tolerant phenotype that was observed in irc22Δ disappeared in the dsk2Δirc22Δ double disruptant, indicating that DSK2 is positively and IRC22 is negatively involved in salt stress tolerance. IRC22 disruption did not affect any responses to DNA damage and oxidative stress when comparing the irc22Δ and wild-type strains. Collectively, these results suggest that Dsk2 and Irc22 are involved in salt stress tolerance in yeast. [ABSTRACT FROM AUTHOR]

Iberian dry-cured ham is colonised by moulds during the ripening process. The environmental conditions occurring during the process including the salt content predisposes the surface to colonisation by Penicillium species, including Penicillium nordicum which can contaminate the curing ham with ochratoxin A (OTA). The objective of this study was to examine the effect of NaCl (10% and 22%=0.94 and 0.87 water activity (aw)) on the activation of two genes involved in the biosynthetic pathway for OTA production, otapksPN and otanpsPN, relative growth and phenotypic OTA production by three strains of P. nordicum (CBS 110.769, FHSCC1 and FHSCC2) on a ham-based medium over a period of 12days at 25°C. Growth of the three strains was faster at 0.87 than 0.94 aw on the ham-based media. However, some intra- and inter-strain differences were observed. Of the three strains, only two (CBS 110.789; FHSCC2) were able to express the two genes involved in the biosynthesis of OTA in the two salt treatments. RT-qPCR showed that the temporal expression of the two genes (otapksPN and otanpsPN) was relatively similar for the wild type strain (FHSCC2) at both 0.94 and 0.87 aw over the 12day period. However, in the type strain (CBS 110.769) expression increased rapidly at 0.94 aw but was significantly lower at 0.87 aw. Expression of these two genes occurred after 3day incubation, while phenotypic OTA production was observed only after 6days in the two toxigenic strains. The other strain did not produce any OTA. The OTA concentrations confirmed the results observed with the molecular tools. This suggests that the RT-qPCR gene expression of these two genes may be a good early indicator of potential contamination of dry-cured ham with OTA during dry-cured ham ripening. [ABSTRACT FROM AUTHOR]

Candida versatilis is a yeast with a complex salt-tolerant system. It can maintain normal physiological activities and metabolic fermentation under a high-salt environment. The cellular mechanisms of adaptation to salt stress in strains of a wild type of C. versatilis (WT) and S3-5, genome shuffling strains of C. versatilis with improved tolerance to salt, were investigated. The content of intra- and extra-cellular glycerol, intra-cellular Na, as well as membrane fluidity and permeability, were determined under salt-stressed yeast growth conditions. The results showed that Na/H-antiporter played a primary role in Na extrusion and H-ATPase has been associated with yeast survival under salt stress. Considerable amounts of glycerol were produced and secreted by the yeast to outside the cell under this salt stress. Changes in the portion of membrane saturated and unsaturated fatty acid composition of C. versatilis in response to osmotic stress lead to membrane permeability and fluidity decreases. They could restrict the influx of Na, enhance H-ATPase activity, and prevent leakage of glycerol across the cell membrane under osmotic stress. The salt tolerance of genome shuffled strain S3-5 was higher than WT. It could be correlated with a higher level of intra-cellular accumulation of glycerol and sodium ions in cells of S3-5 than WT as well as a higher portion of oleic fatty acid (C18: 1) and a lower level of linoleic acid (C18: 2) in cell membranes of the studied yeast mutant. It can be concluded that S3-5 improved physiological regulatory mechanisms of response to salt stress, such as decreased membrane fluidity and a permeability that rapidly adjusted to osmotic stress. [ABSTRACT FROM AUTHOR]

Twenty five fungal cultures ( Penicillium spp.), isolated from soil samples from the high altitudes in the Indian Himalayan region, have been characterized following polyphasic approach. Colony morphology performed on five different media gave varying results; potato dextrose agar being the best for the vegetative growth and sporulation as well. Microscopic observations revealed 18 isolates to be biverticillate and 7 monoverticillate. Based on the phenotypic characters (colony morphology and microscopy), all the isolates were designated to the genus Penicillium. Exposure to low temperature resulted in enhanced sporulation in 23 isolates, while it ceased in case of two. The fungal isolates produced watery exudates in varying amount that in many cases increased at low temperature. All the isolates could grow between 4 and 37 °C, (optimum 24 °C), hence considered psychrotolerant. While all the isolates could tolerate pH from 2 to 14 (optimum 5-9), 7 isolates tolerated pH 1.5 as well. While all the fungal isolates tolerated salt concentration above 10 %; 10 isolates showed tolerance above 20 %. Based on ITS region (ITS1-5.8S-ITS2) analysis the fungal isolates belonged to 25 different species of Penicillium (showing similarity between 95 and 100 %). Characters like tolerance for low temperature, wide range of pH, and high salt concentration, and enhancement in sporulation and production of secondary metabolites such as watery exudates at low temperature can be attributed to the ecological resilience possessed by these fungi for survival under low temperature environment of mountain ecosystem. [ABSTRACT FROM AUTHOR]

The halotolerant fungus Aspergillus glaucus CCHA was isolated from the surface of wild vegetation around a saltern with the salinity range being 0-31%. Here, a full-length cDNA library of A. glaucus under salt stress was constructed to identify genes related to salt tolerance, and one hundred clones were randomly selected for sequencing and bioinformatics analysis. Among these, 82 putative sequences were functionally annotated as being involved in signal transduction, osmolyte synthesis and transport, or regulation of transcription. Subsequently, the cDNA library was transformed into E. coli cells to screen for putative salt stress-related clones. Five putative positive clones were obtained from E. coli cells grown on LB agar containing 1 M NaCl, on which they showed rapid growth compared to the empty vector control line. Analysis of transgenic Arabidopsis thaliana lines overexpressing CCHA-2142 demonstrated that the gene conferred increased salt tolerance to plants as well by protecting the cellular membranes, suppressing the inhibition of chlorophyll biosynthesis. These results highlight the utility of this A. glaucus cDNA library as a tool for isolating and characterizing genes related to salt tolerance. Furthermore, the identified genes can be used for the study of the underlying biology of halotolerance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of NaCl on the heavy metal tolerance and bioaccumulation of two yeasts. [•] NaCl improves the Cd2+ and Zn2+ tolerance but reduced the Cu2+ tolerance. [•] NaCl increases the bioaccumulation capacities of Cu2+, Zn2+, and Fe3+. [•] NaCl affects both the intracellular and cell-surface heavy metal bioaccumulation. [•] Z. rouxii is preferred to S. cerevisiae for heavy metal removal when NaCl exists. [Copyright &y& Elsevier]

Abstract: Fungi from the food-borne basidiomycetous genus Wallemia, which comprises Wallemia ichthyophaga, Wallemia muriae and Wallemia sebi, are among the most xerophilic organisms described. Their morphological adaptations to life at high NaCl concentrations are reflected in increased cell-wall thickness and size of cellular aggregates. The objectives of this study were to examine their growth and to define cell morphology and any ultrastructural cell-wall changes when these fungi are grown in low and high glucose and honey concentrations, as environmental osmolytes. We analysed their growth parameters and morphological characteristics by light microscopy and transmission and scanning electron microscopy. Wallemia ichthyophaga grew slowly in all of the sugar-based media, while W. muriae and W. sebi demonstrated better growth. Wallemia ichthyophaga adapted to the high glucose and honey concentrations with formation of larger cellular aggregates, while cell-wall thickness was increased only at the high glucose concentration. Wallemia muriae and W. sebi demonstrated particularly smaller sizes of hyphal aggregates at the high glucose concentration, and different and less explicit changes in cell-wall thickness. Adaptive responses show that the phylogenetically more distant W. ichthyophaga is better adapted to high salt conditions, whereas W. muriae and W. sebi cope better with a high sugar environment. [Copyright &y& Elsevier]

With the aim of developing a new easy-to-use method for rescuing flood-damaged paper, the effect of saltwater on the inhibition of fungal growth on paper was investigated. This procedure could be used instead of, or assisted by freeze drying. Cellulose-digesting Trichoderma reesei, three types of fungi representative of fungi growing on paper (T. reesei, Aspergillus terreus, and Aureobasidium pullulans) and various naturally airborne fungi were cultured on cellulosic materials in liquid media containing artificial seawater with different salt concentrations. The addition of salts successfully inhibited the growth of T reesei on microcrystalline cellulose at the concentration of 3.2% (m/m) or higher. The critical salt concentration, 3.2%, is within the general range of salt content in seawater. Other solutions of salts similar to sodium chloride also inhibited fungal growth. Although the observed growth-inhibiting effect was attributed to the high osmotic pressure of the salt solution, physiological effects depending on ion species used were also considered to be possible. The growth of all three types of fungi on copy paper was inhibited effectively when the salt concentration was increased. The growth of various fungi on pure cellulose, with enough oxygen supplied to pores, was completely inhibited (as assessed by visual examination) for 24 days at salt concentrations of 3.5% (m/m) or greater. The fact that the effect of saltwater on cellulosic materials was observed even under optimum medium conditions implies that fungi would be considerably inhibited on flood-damaged paper immersed in saltwater. This method is a promising first aid measure when circumstances do not allow for flood-damaged paper to be dried immediately. [ABSTRACT FROM AUTHOR]

During saline stress, Saccharomyces cerevisiae changes its metabolic fluxes through the direct accumulation of metabolites such as glycerol and trehalose, which in turn provide tolerance to the cell against stress. Previous research shows that the various controls at both transcriptional and translational levels decide the phenomenon of stress, but details about such transition is still not very clear. This paper attempts to extract some hidden features through the information extraction approach from DNA microarray data during transition to osmotic tolerance, which are expected to be important in directing to the tolerance stage upon encountering osmotic stress in yeast. Time course of DNA microarray data during osmotic tolerance was analyzed by computational approach ‘self-organizing map (SOM) extended with hierarchical clustering’. Since eukaryotic gene expression is governed by short regulatory sequences found upstream in promoter regions, therefore clusters containing the similar profiles obtained by SOM were further analyzed for overrepresentation of known regulatory binding sites in promoter region. It was found that apart from known and expected ‘STRE’ during osmotic stress, the ‘GCN4’ binding site is also found to be significant. Hence, it was suggested that the process of osmotic tolerance proceeds through a stage of amino acid starvation. The intracellular amino acids pool also found to be depleted during transition and restoration is faster in brewing strain than laboratory strain. Experiments involving supplementation of amino acids helps in reducing the lag time for recovery, which was found to be similar to that of brewing strain. [ABSTRACT FROM AUTHOR]