Filamentous fungi are widely used for producing cellulolytic enzymes to degrade lignocellulosic biomass. Microbial resources from Tibet have received great attention due to the unique geographic and ...climatic conditions in the Qinghai-Tibet Plateau. However, studies on cellulase producing fungal strains originated from Tibet remain very limited, and so far no studies have been focused on regulation of cellulase production of the specific strains thereof. Here, filamentous fungal strains were isolated from soil, plant, and other environments in Tibet, and cellulase-producing strains were further investigated. A total of 88 filamentous fungal strains were identified, and screening of cellulase-producing fungi revealed that 16 strains affiliated with the genera
Penicillium
,
Trichoderma
,
Aspergillus
, and
Talaromyces
exhibited varying cellulolytic activities. Among these strains,
T. harzianum
isolate LZ117 is the most potent producer. Comparative transcriptome analysis using
T. harzianum
LZ117 and the control strain
T. harzianum
K223452 cultured on cellulose indicated an intensive modulation of gene transcription related to protein synthesis and quality control. Furthermore, transcription of
xyr1
which encodes the global transcriptional activator for cellulase expression was significantly up-regulated. Transcription of
cre1
and other predicted repressors controlling cellulase gene expression was decreased in
T. harzianum
LZ117, which may contribute to enhancing formation of primary cellulases. To our knowledge, this is the first report that the transcription landscape at the early enzyme production stage of
T. harzianum
was comprehensively described, and detailed analysis on modulation of transporters, regulatory proteins as well as protein synthesis and processing was presented. Our study contributes to increasing the catalog of publicly available transcriptome data from
T. harzianum
, and provides useful clues for unraveling the biotechnological potential of this species for lignocellulosic biorefinery.
Regulated Forms of Cell Death in Fungi Gonçalves, A Pedro; Heller, Jens; Daskalov, Asen ...
Frontiers in microbiology,
09/2017, Letnik:
8
Journal Article
Recenzirano
Odprti dostop
Cell death occurs in all domains of life. While some cells die in an uncontrolled way due to exposure to external cues, other cells die in a regulated manner as part of a genetically encoded ...developmental program. Like other eukaryotic species, fungi undergo programmed cell death (PCD) in response to various triggers. For example, exposure to external stress conditions can activate PCD pathways in fungi. Calcium redistribution between the extracellular space, the cytoplasm and intracellular storage organelles appears to be pivotal for this kind of cell death. PCD is also part of the fungal life cycle, in which it occurs during sexual and asexual reproduction, aging, and as part of development associated with infection in phytopathogenic fungi. Additionally, a fungal non-self-recognition mechanism termed heterokaryon incompatibility (HI) also involves PCD. Some of the molecular players mediating PCD during HI show remarkable similarities to major constituents involved in innate immunity in metazoans and plants. In this review we discuss recent research on fungal PCD mechanisms in comparison to more characterized mechanisms in metazoans. We highlight the role of PCD in fungi in response to exogenic compounds, fungal development and non-self-recognition processes and discuss identified intracellular signaling pathways and molecules that regulate fungal PCD.
Abstract In filamentous fungi, microtubules are important for polar growth and morphological maintenance and serve as rails for intracellular trafficking. The molecular mechanisms associated with ...microtubules have been analyzed. However, little is known about when and where tubulin, a component of microtubules, is biosynthesized in multinuclear and multicellular filamentous fungi. In this study, we visualized microtubules based on the enhanced green fluorescence protein (EGFP)-labeled α-tubulin and β-tubulin mRNA tagged by the EGFP-mediated MS2 system in living yellow Koji mold Aspergillus oryzae cells in order to understand the spatiotemporal production mechanism of tubulin. We found that mRNA of btuA , encoding for β-tubulin, localized at dot-like structures through the apical, middle and basal regions of the hyphal cells. In addition, some btuA mRNA dots showed microtubule-dependent motor protein-like dynamics in the cells. Furthermore, it was found that btuA mRNA dots were decreased in the cytoplasm just before mitosis but increased immediately after mitosis, followed by a gradual decrease. In summary, the localization and abundance of β-tubulin mRNA is spatiotemporally regulated in living A. oryzae hyphal cells.
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based species identification has found its place in many clinical routine diagnostic laboratories over the ...past years, allowing significantly reduced turnaround times and high-precision results. With regard to MALDI-TOF MS for filamentous fungi, here, we discuss different approaches for sample processing and growth conditions before analysis. In particular, we review the performances of different commercially available databases as well as the potential of complementary (self-constructed) in-house databases.
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•The synergistic effects of algae and fungi greatly enhanced the pollutants removal.•The protein and lipid yield were significantly improved in the co-culture process.•Simultaneous ...culture and harvesting of cells was achieved in an integrated process.
A novel method of one-step co-cultivation and harvesting of microalgae and fungi, for efficient starch wastewater treatment and high-value biomass production was developed. By combination of Aspergillus oryzae and Chlorella pyrenoidosa, nutrients in wastewater could be converted to useful microbial biomass, while the wastewater was purified. Moreover, the microalgae C. pyrenoidosa could gradually be encapsulated in fungal pellets which promoted the biomass harvesting. The free algal cells could be completely harvested by fungal pellets within 72 h. The synergistic effects between them greatly improved the removal efficiencies of main pollutants as the removal efficiency of COD, TN, and TP reached 92.08, 83.56, and 96.58 %, respectively. In addition, the final biomass concentration was higher than that of individual cultures. The protein and lipid concentration was also significantly improved and reached 1.92 and 0.99 g/L, respectively. This study provides a simple and efficient strategy for simultaneous wastewater treatment and high-value biomass production.
Wild-type strains of Aspergillus oryzae develop yellow, yellow-green, green, or brown conidia. Previous reports suggested that the conidiation initiates with the biosynthesis of a yellow pigment YWA1 ...from acetyl-CoA by a polyketide synthase encoded by wA (AO090102000545). This is followed by the conversion to other pigment by a laccase encoded by yA (AO090011000755). Based on orthologous pathways in other aspergilli, it is reasonable to hypothesize that in addition to yA, AO090102000546 encoding laccase and AO090005000332 encoding Ayg1-like hydrolase play a role in A. oryzae conidial pigment biosynthesis. However, the involvement of these two genes in conidial pigmentation remains unclear. In this study, we tested this hypothesis by assessing the conidial colors of both disruption and overexpression mutants to verify whether AO090102000546 and AO090005000332 were associated with the conidial pigmentation. Here, observation of single, double, and triple disruptants of these three genes suggested that conidial pigments were synthesized by two laccase genes, AO090011000755 and AO090102000546, whereas Ayg1-like hydrolase gene AO090005000332 was proven to have no obvious association with the synthesis. This was corroborated by observing the phenotype of each overexpression mutant. Interestingly, AO090005000332 overexpression mutant produced smoky yellow-green conidia, different from the wild-type strain. Thus, the AO090005000332-encoded protein is likely to maintain the enzymatic activity. However, the expression level was observed to be one-third of that of AO090102000546 and one-seventh of that of AO090011000755. Consequently, apparent lack of obvious contribution of AO090005000332 to conidial pigmentation could be attributed to its low expression level. Expression analysis indicated similar profiles in several wild-type strains.
Microbial lipids, also known as single-cell oils (SCOs), are highly attractive feedstocks for biodiesel production due to their fast production rates, minimal labor requirements, independence from ...seasonal and climatic changes, and ease of scale-up for industrial processing. Among the SCO producers, the less explored filamentous fungi (molds) exhibit desirable features such as a repertoire of hydrolyzing enzymes and a unique pellet morphology that facilitates downstream harvesting. Although several oleaginous filamentous fungi have been identified and explored for SCO production, high production costs and technical difficulties still make the process less attractive compared to conventional lipid sources for biodiesel production. This review aims to highlight the ability of filamentous fungi to hydrolyze various organic wastes for SCO production and explore current strategies to enhance the efficiency and cost-effectiveness of the SCO production and recovery process. The review also highlights the mechanisms and components governing lipogenic pathways, which can inform the rational designs of processing conditions and metabolic engineering efforts for increasing the quality and accumulation of lipids in filamentous fungi. Furthermore, we describe other process integration strategies such as the co-production with hydrogen using advanced fermentation processes as a step toward a biorefinery process. These innovative approaches allow for integrating upstream and downstream processing units, thus resulting in an efficient and cost-effective method of simultaneous SCO production and utilization for biodiesel production.
The study aimed to evaluate the use of increasing levels of defatted rice bran fermented by Rhizopus oryzae in the diets of juveniles of mullet fish Mugil liza, assessing growth parameters, proximal ...carcass composition, and lipid peroxidation (TBARS) in the liver and intestine. Six experimental diets were formulated: a control treatment without rice bran, a second treatment with the inclusion of 200 g kg−1 of defatted rice bran without fermentation (DRB200), and the remaining treatments received diets with the inclusion of 100, 200, 300, or 400 g kg−1 of fermented bran. The experimental design used 216 mullet juveniles (2.10 ± 0.04 g) randomly distributed in a recirculation system composed of 18 tanks, divided into six treatments and three replications, with 12 fish per experimental unit. During the experiment, fish were fed ad libitum three times a day, for 50 days. No mortalities were recorded during the experimentation. The performance variables showed that an inclusion equal or higher than 200 g kg−1 of fermented rice bran resulted in decreased growth. Furthermore, in carcass proximal composition, the lipid content decreased with higher inclusion levels of fermented rice bran and the control treatment showed the highest lipid content, while the ash content of fish carcasses increased with the higher inclusion of the tested ingredient. No differences were recorded for TBARS in the liver and intestine. According to the results, we recommend a maximum inclusion of 100 g kg−1 fermented rice bran in diets for M. liza juveniles.
•Fermentation of rice bran by Rhizopus oryzae fungus improved by 32% the amount of protein.•Defatted Rice Bran fermented can be included up to 100 g kg−1 for mullet without compromising growth performance.•Inclusions equal to or greater than 200 g kg-1 have an adverse effect on growth, but not on flesh quality.
Antarctica is the coldest, windiest, and driest continent on Earth. In this sense, microorganisms that inhabit Antarctica environments have to be adapted to harsh conditions. Fungal strains ...affiliated with Ascomycota and Basidiomycota phyla have been recovered from terrestrial and marine Antarctic samples. They have been used for the bioprospecting of molecules, such as enzymes. Many reports have shown that these microorganisms produce cold-adapted enzymes at low or mild temperatures, including hydrolases (e.g. α-amylase, cellulase, chitinase, glucosidase, invertase, lipase, pectinase, phytase, protease, subtilase, tannase, and xylanase) and oxidoreductases (laccase and superoxide dismutase). Most of these enzymes are extracellular and their production in the laboratory has been carried out mainly under submerged culture conditions. Several studies showed that the cold-adapted enzymes exhibit a wide range in optimal pH (1.0-9.0) and temperature (10.0-70.0 °C). A myriad of methods have been applied for cold-adapted enzyme purification, resulting in purification factors and yields ranging from 1.70 to 1568.00-fold and 0.60 to 86.20%, respectively. Additionally, some fungal cold-adapted enzymes have been cloned and expressed in host organisms. Considering the enzyme-producing ability of microorganisms and the properties of cold-adapted enzymes, fungi recovered from Antarctic environments could be a prolific genetic resource for biotechnological processes (industrial and environmental) carried out at low or mild temperatures.
Introduction: Mycotic keratitis is one of the commonest causes of eye infections especially in male which works mainly in outdoor. Filamentous fungi (mould-like fungi) were the common cause of ...Mycotic keratitis and common presentations seen in developing countries. The aim of present study assess predisposing factors and microbial profile of Mycotic keratitis in central India. Methods: The study was conducted in the collaboration of Department of Microbiology and Ophthalmology in G. R. Medical College, Gwalior, India. Samples were collected from corneal scraping by sterile cotton swab and inoculated on culture media Sabouraud dextrose agar (SDA) for fungal culture. Material obtained from corneal scrapping also performed 10% KOH mount preparation, gram’s staining and Lactophenol cotton blue (LPCB) mount. Identification of fungal isolates was done by colony morphology, growth characteristics and relevant standard tests. Results: A total of 237 out of 740 (32%) fungal isolates was obtained from suspected patients of Mycotic keratitis, out of which Fusarium species (33.2%) was the most predominant followed by Curvularia species (21.9%) and Aspergillus species (16.7%), Ocular trauma was the key predisposing factors. Conclusion: Trauma was the key predisposing factor of keratitis because of filamentous fungi. The commonestcausative agent of fungal keratitis in current study was Fusarium species followed by Curvularia species. Early proper diagnosis and management of fungal keratitis reduces the ophthalmic morbidity and mortality
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