scholarly journals Two Novel, Putatively Cell Wall-Associated and Glycosylphosphatidylinositol-Anchored α-Glucanotransferase Enzymes of Aspergillus niger

2007 ◽  
Vol 6 (7) ◽  
pp. 1178-1188 ◽  
Author(s):  
R. M. van der Kaaij ◽  
X.-L. Yuan ◽  
A. Franken ◽  
A. F. J. Ram ◽  
P. J. Punt ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Niger ◽  
Fungal Species ◽  
Degree Of Polymerization ◽  
Reaction Products ◽  
Calcofluor White ◽  
Fungal Cell ◽  
Transglycosylation Activity ◽  
Glycosidic Bonds ◽  
A Cell

ABSTRACT In the genome sequence of Aspergillus niger CBS 513.88, three genes were identified with high similarity to fungal α-amylases. The protein sequences derived from these genes were different in two ways from all described fungal α-amylases: they were predicted to be glycosylphosphatidylinositol anchored, and some highly conserved amino acids of enzymes in the α-amylase family were absent. We expressed two of these enzymes in a suitable A. niger strain and characterized the purified proteins. Both enzymes showed transglycosylation activity on donor substrates with α-(1,4)-glycosidic bonds and at least five anhydroglucose units. The enzymes, designated AgtA and AgtB, produced new α-(1,4)-glycosidic bonds and therefore belong to the group of the 4-α-glucanotransferases (EC 2.4.1.25). Their reaction products reached a degree of polymerization of at least 30. Maltose and larger maltooligosaccharides were the most efficient acceptor substrates, although AgtA also used small nigerooligosaccharides containing α-(1,3)-glycosidic bonds as acceptor substrate. An agtA knockout of A. niger showed an increased susceptibility towards the cell wall-disrupting compound calcofluor white, indicating a cell wall integrity defect in this strain. Homologues of AgtA and AgtB are present in other fungal species with α-glucans in their cell walls, but not in yeast species lacking cell wall α-glucan. Possible roles for these enzymes in the synthesis and/or maintenance of the fungal cell wall are discussed.

scholarly journals Fungal α-arabinofuranosidases of glycosyl hydrolase families 51 and 54 show a dual arabinofuranosyl- and galactofuranosyl-hydrolyzing activity

2012 ◽  
Vol 393 (8) ◽  
pp. 767-775 ◽  
Author(s):  
Boris Tefsen ◽  
Ellen L. Lagendijk ◽  
Joohae Park ◽  
Michiel Akeroyd ◽  
Doreen Schachtschabel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Enzyme Activity ◽  
Molecular Modeling ◽  
Aspergillus Niger ◽  
Glycosyl Hydrolase ◽  
Hydrolase Activity ◽  
Gene Encoding ◽  
A Cell ◽  
Or Gene

Abstract Aspergillus niger possesses a galactofuranosidase activity, however, the corresponding enzyme or gene encoding this enzyme has never been identified. As evidence is mounting that enzymes exist with affinity for both arabinofuranose and galactofuranose, we investigated the possibility that α-l-arabinofuranosidases, encoded by the abfA and abfB genes, are responsible for the galactofuranosidase activity of A. niger. Characterization of the recombinant AbfA and AbfB proteins revealed that both enzymes do not only hydrolyze p-nitrophenyl-α-l-arabinofuranoside (pNp-α-Araf) but are also capable of hydrolyzing p-nitrophenyl-β-d-galactofuranoside (pNp-β-Galf). Molecular modeling of the AbfB protein with pNp-β-Galf confirmed the possibility for AbfB to interact with this substrate, similarly as with pNp-α-Araf. We also show that galactomannan, a cell wall compound of A. niger, containing β-linked terminal and internal galactofuranosyl moieties, can be degraded by an enzyme activity that is present in the supernatant of inulin-grown A. niger. Interestingly, purified AbfA and AbfB did not show this hydrolyzing activity toward A. nigergalactomannan. In summary, our studies demonstrate that AbfA and AbfB, α-l-arabinofuranosidases from different families, both contain a galactofuranose (Galf)-hydrolyzing activity. In addition, our data support the presence of a Galf-hydrolase activity expressed by A. niger that is capable of degrading fungal galactomannan.

scholarly journals Structure, Cellular Distribution, Antigenicity, and Biological Functions of Fonsecaea pedrosoi Ceramide Monohexosides

2005 ◽  
Vol 73 (12) ◽  
pp. 7860-7868 ◽  
Author(s):  
Leonardo Nimrichter ◽  
Mariana D. Cerqueira ◽  
Eduardo A. Leitão ◽  
Kildare Miranda ◽  
Ernesto S. Nakayasu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Difference ◽  
Structural Diversity ◽  
Fungal Species ◽  
Hydroxyl Group ◽  
Current Evidence ◽  
Fonsecaea Pedrosoi ◽  
Fungal Cell ◽  
Long Chain Base ◽  
Antifungal Action

ABSTRACT Monohexosylceramides (CMHs, or cerebrosides) have been reported as membrane and cell wall constituents of both pathogenic and nonpathogenic fungi, presenting remarkable differences in their ceramide moiety compared to mammalian CMHs. Current evidence suggests that CMHs are involved in fungal differentiation and growth and contribute to host immune response. Here we describe a structural diversity between cerebrosides obtained from different forms of the human pathogen Fonsecaea pedrosoi. The major CMH species produced by conidial forms displayed the same structure previously demonstrated by our group for mycelia, an N-2′-hydroxyhexadecanoyl-1-β-d-glucopyranosyl-9-methyl-4,8-sphingadienine. However, the major cerebroside species purified from sclerotic cells carries an additional hydroxyl group, bound to its long-chain base. The structural difference between cerebrosides from mycelial and sclerotic cells was apparently not relevant for their antigenicity, since they were both recognized at similar levels by sera from individuals with chromoblastomycosis and a monoclonal antibody to a conserved cerebroside structure. Preincubation of fungal cells with anti-CMH monoclonal antibodies had no effect on the interaction of F. pedrosoi sclerotic cells with murine macrophages. In contrast to what has been described for other fungal species, sclerotic bodies are resistant to the antifungal action of anti-CMH antibodies. Immunofluorescence analysis showed that recognition of sclerotic cells by these antibodies only occurs at cell wall regions in which melanization is not evident. Accordingly, melanin removal with alkali results in an increased reaction of fungal cells with anti-CMH antibodies. Our results indicate that cerebroside expression in F. pedrosoi cells is associated with dimorphism and melanin assembly on the fungal cell wall.

scholarly journals Deletion of YLR358C Contributes to Reduce Cell Wall Integrity in Saccharomyces Cerevisiae

2022 ◽  
Author(s):  
Yu Zhang ◽  
Mengyan Li ◽  
Hanying Wang ◽  
Juqing Deng ◽  
Jianxing Liu ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Sodium Dodecyl ◽  
Wall Stress ◽  
Pathogenic Fungi ◽  
Cell Wall Integrity ◽  
Calcofluor White ◽  
Fungal Cell ◽  
Reading Frame ◽  
Stress Signals

Abstract The mechanism of fungal cell wall synthesis and assembly is still unclear. Saccharomyces cerevisiae (S. cerevisiae) and pathogenic fungi are conserved in cell wall construction and response to stress signals, and often respond to cell wall stress through activated cell wall integrity (CWI) pathways. Whether the YLR358C open reading frame regulates CWI remains unclear. This study found that the growth of S. cerevisiae with YLR358C knockout was significantly inhibited on the medium containing different concentrations of cell wall interfering agents Calcofluor White (CFW), Congo Red (CR) and sodium dodecyl sulfate (SDS). CFW staining showed that the cell wall chitin was down-regulated, and transmission electron microscopy also observed a decrease in cell wall thickness. Transcriptome sequencing and analysis showed that YLR358C gene may be involved in the regulation of CWI signaling pathway. It was found by qRT-PCR that WSC3, SWI4 and HSP12 were differentially expressed after YLR358C was knocked out. The above results suggest that YLR358C may regulate the integrity of the yeast cell walls and has some potential for application in fermentation.

scholarly journals The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

Microbiology ◽  
2009 ◽  
Vol 155 (6) ◽  
pp. 2004-2020 ◽  
Author(s):  
Emilia Moreno-Ruiz ◽  
Giuseppe Ortu ◽  
Piet W. J. de Groot ◽  
Fabien Cottier ◽  
Céline Loussert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Fungal Pathogens ◽  
High Sensitivity ◽  
Wall Structure ◽  
Minor Role ◽  
Cell Wall Proteins ◽  
Calcofluor White ◽  
Fungal Cell ◽  
A Minor

The fungal cell wall is essential in maintaining cellular integrity and plays key roles in the interplay between fungal pathogens and their hosts. The PGA59 and PGA62 genes encode two short and related glycosylphosphatidylinositol-anchored cell wall proteins and their expression has been previously shown to be strongly upregulated when the human pathogen Candida albicans grows as biofilms. Using GFP fusion proteins, we have shown that Pga59 and Pga62 are cell-wall-located, N- and O-glycosylated proteins. The characterization of C. albicans pga59Δ/pga59Δ, pga62Δ/pga62Δ and pga59Δ/pga59Δ pga62Δ/pga62Δ mutants suggested a minor role of these two proteins in hyphal morphogenesis and that they are not critical to biofilm formation. Importantly, the sensitivity to different cell-wall-perturbing agents was altered in these mutants. In particular, simultaneous inactivation of PGA59 and PGA62 resulted in high sensitivity to Calcofluor white, Congo red and nikkomicin Z and in resistance to caspofungin. Furthermore, cell wall composition and observation by transmission electron microscopy indicated an altered cell wall structure in the mutant strains. Collectively, these data suggest that the cell wall proteins Pga59 and Pga62 contribute to cell wall stability and structure.

scholarly journals Unconventional Constituents and Shared Molecular Architecture of the Melanized Cell Wall of C. neoformans and Spore Wall of S. cerevisiae

2020 ◽  
Vol 6 (4) ◽  
pp. 329
Author(s):  
Christine Chrissian ◽  
Coney Pei-Chen Lin ◽  
Emma Camacho ◽  
Arturo Casadevall ◽  
Aaron M. Neiman ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Building Blocks ◽  
Cell Types ◽  
Resistant Cell ◽  
Spore Wall ◽  
Fungal Species ◽  
Resonance Spectroscopy ◽  
Molecular Architecture ◽  
Fungal Cell

The fungal cell wall serves as the interface between the cell and the environment. Fungal cell walls are composed largely of polysaccharides, primarily glucans and chitin, though in many fungi stress-resistant cell types elaborate additional cell wall structures. Here, we use solid-state nuclear magnetic resonance spectroscopy to compare the architecture of cell wall fractions isolated from Saccharomyces cerevisiae spores and Cryptococcus neoformans melanized cells. The specialized cell walls of these two divergent fungi are highly similar in composition. Both use chitosan, the deacetylated derivative of chitin, as a scaffold on which a polyaromatic polymer, dityrosine and melanin, respectively, is assembled. Additionally, we demonstrate that a previously identified but uncharacterized component of the S. cerevisiae spore wall is composed of triglycerides, which are also present in the C. neoformans melanized cell wall. Moreover, we identify a tyrosine-derived constituent in the C. neoformans wall that, although it is not dityrosine, is a non-pigment constituent of the cell wall. The similar composition of the walls of these two phylogenetically distant species suggests that triglycerides, polyaromatics, and chitosan are basic building blocks used to assemble highly stress-resistant cell walls and the use of these constituents may be broadly conserved in other fungal species.

scholarly journals A Novel Screening Method for Cell Wall Mutants in Aspergillus niger Identifies UDP-Galactopyranose Mutase as an Important Protein in Fungal Cell Wall Biosynthesis

Genetics ◽  
2008 ◽  
Vol 178 (2) ◽  
pp. 873-881 ◽  
Author(s):  
Robbert A. Damveld ◽  
Angelique Franken ◽  
Mark Arentshorst ◽  
Peter J. Punt ◽  
Frans M. Klis ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Niger ◽  
Screening Method ◽  
Fungal Cell Wall ◽  
Cell Wall Biosynthesis ◽  
Fungal Cell ◽  
Important Protein

scholarly journals Dinamika Populasi Jamur Pada Media Starter Tepung Beras Diperkaya Nutrisi Potato Dextrose Agar

2019 ◽  
Vol 5 (1) ◽  
pp. 1-6
Author(s):  
Anindyta Robiatul Adawiyah ◽  
Ahmad Syauqi ◽  
Hasan Zayadi
Keyword(s):  
Aspergillus Niger ◽  
Candida Utilis ◽  
Trichoderma Viride ◽  
Growth Dynamics ◽  
Rice Flour ◽  
Fungal Species ◽  
Potato Dextrose Agar ◽  
Test Method ◽  
Composite Flour ◽  
Fungal Cell

Yeast and fungus are important biomass in the food industry. Rice flour is one of the alternative basic ingredients of composite flour and consists of carbohydrates, fats, proteins, minerals and vitamins. Yeast multiplies by a process known as germination, which causes fermentation. This study aims to determine the development of fungal cell population dynamics in making starter with rice flour rich in PDA (Potato Dextrose Agar) nutrition. PDA (Potato Dextrose Agar) is one of the good media used to breed a microorganism, either in the form of fungus / function, bacteria, or living cells. The method used in this study is a different test method for two populations with 2 variables with PDA levels of 0% and 4% with 9 times of repetition. Which is observed once every eight hours the growth dynamics of the fungus by identifying the following fungal species Aspergillus niger is white and has a good composition, Candida utilis is white, Hansenulla anomala is opaque, Trichoderma viride is clear. Keywords: Rice flour, Yeast, PDA (Potato Dextrose Agar), Aspergillus niger, Candida utilis, Trichoderma viride, Hansenula saturnus. ABSTRAK Jamur adalah biomasa yang penting di dalam industri makanan. Tepung beras merupakan salah satu alternatif bahan dasar dari tepung komposit dan terdiri atas karbohidrat, lemak, protein, mineral dan vitamin. Starter adalah populasi mikroba dalam jumlah dan kondisi fisiologis yang siap diinokulasikan pada media fermentasi. Penelitian ini bertujuan Untuk mengetahui perkembangan dinamika populasi sel jamur pada pembuatan starter dengan media tepung beras kaya nutrisi PDA (Potato Dextrose Agar). PDA (Potato Dextrose Agar) merupakan salah satu media yang baik digunakan untuk membiakkan suatu mikroorganisme, baik itu berupa cendawan/fungsi, bakteri, maupun sel mahluk hidup. Metode yang digunakan pada penelitian ini adalah metode Uji beda rerata dua populasi dengan 2 variabel dengan kadar PDA 0% dan 4% dengan 9 kali ulangan waktu. Yang mana pada setiap 8 jam sekali diamati dinamika pertumbuhan jamurnya dengan mengidentifikasi spesies jamur sebagai berikut Aspergillus niger berwarna putih dan berbenang, Candida utilis berwarna putih, Hansenulla saturnus berwarna buram, Trichoderma viride berwarna bening. Kata Kunci : Tepung beras, Ragi, PDA (Potato Dextrose Agar), Aspergillus niger, Candida utilis, Trichoderma viride, Hansenula saturnus.

scholarly journals Spatial mapping of immunological epitopes in the Candida cell wall using C-type lectin probes

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Ingrida Vendele ◽  
Ten Feizi ◽  
Maria Spyrou ◽  
Mark Stappers ◽  
Gordon Brown ◽  
...  
Keyword(s):  
Cell Wall ◽  
Three Dimensional ◽  
Fungal Species ◽  
Physiological Adaptation ◽  
Dimensional Structure ◽  
Immune Reactivity ◽  
Fungal Cell ◽  
Lectin Receptor ◽  
Composition Changes

The primary recognition event between a fungal pathogen and the immune system normally involves the engagement of a pattern recognition receptor with specific components of the cell wall. However, the cell wall is a complex three dimensional structure whose composition changes rapidly in accordance with environmental stimuli. Therefore it is important to know what is the precise nature of the primary recognition event, how many events occur to activate the immune response and how these recognition events are affected by changes in cell wall architecture, cellular morphogenesis and physiological adaptation of the pathogen to specific niches in the human body. We address this fundamental question using four soluble immune C-Type lectin receptor-probes which recognize specific mannans and β-1,3 glucan in the cell wall. We use these C-type lectin probes to demonstrate that mannan epitopes are differentially distributed in the inner and outer layers of fungal cell wall in a clustered or diffuse manner. Immune reactivity of fungal cell surfaces did not correlate with relatedness of different fungal species, and mannan-detecting receptor-probes discriminated between cell surface mannans generated by the same fungus growing under different conditions. These studies demonstrate that mannan-epitopes within fungal cell walls are differentially distributed and dynamically expressed as the fungus adapted to microenvironments that would be encountered in vivo.

scholarly journals Unravelling the enigmatic origin of calcitic nanofibres in soils and caves: purely physicochemical or biogenic processes?

2014 ◽  
Vol 11 (1) ◽  
pp. 975-1019
Author(s):  
S. Bindschedler ◽  
G. Cailleau ◽  
O. Braissant ◽  
L. Millière ◽  
D. Job ◽  
...  
Keyword(s):  
Cell Wall ◽  
Current Knowledge ◽  
Enzymatic Digestion ◽  
Global Scale ◽  
Fungal Species ◽  
Fungal Cell Wall ◽  
Fungal Cell ◽  
Widespread Occurrence ◽  
Terrestrial Environments ◽  
New Hypothesis

Abstract. Calcitic nanofibres are ubiquitous habits of secondary calcium carbonate (CaCO3) accumulations observed in calcareous vadose environments. Despite their widespread occurrence, the origin of these nanofeatures remains enigmatic. Three possible mechanisms fuel the debate: (i) purely physicochemical processes, (ii) mineralization of rod-shaped bacteria, and (iii) crystal precipitation on organic templates. Nanofibres can be either mineral (calcitic) or organic in nature. They are very often observed in association with Needle Fibre Calcite (NFC), another typical secondary CaCO3 habit in terrestrial environments. This association has contributed to some confusion between both habits, however they are truly two distinct calcitic features and their recurrent association is likely to be an important fact to help understanding the origin of nanofibres. In this manuscript the different hypotheses that currently exist to explain the origin of calcitic nanofibres are critically reviewed. In addition to this, a new hypothesis for the origin of nanofibres is proposed based on the fact that current knowledge attributes a fungal origin to NFC. As this feature and nanofibres are recurrently observed together, a possible fungal origin for nanofibres which are associated with NFC is investigated. Sequential enzymatic digestion of the fungal cell wall of selected fungal species demonstrates that the fungal cell wall can be a source of organic nanofibres. The obtained organic nanofibres show a striking morphological resemblance when compared to their natural counterparts, emphasizing a fungal origin for part of the organic nanofibres observed in association with NFC. It is further hypothesized that these organic nanofibres may act as templates for calcite nucleation in a biologically-influenced mineralization process, generating calcitic nanofibres. This highlights the possible involvement of Fungi in CaCO3 biomineralization processes, a role still poorly documented at present-day. Moreover, on a global scale, the organomineralization of organic nanofibres into calcitic nanofibres might have a great, however overlooked, impact on the biogeochemical cycles of both Ca and C.

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