scholarly journals Melanin as a Virulence Factor in Different Species of Genus Paracoccidioides

2020 ◽  
Vol 6 (4) ◽  
pp. 291
Author(s):  
Elúzia C. P. Emidio ◽  
Martha E. Urán J. ◽  
Leandro B. R. Silva ◽  
Lucas S. Dias ◽  
Mariana Doprado ◽  
...  
Keyword(s):  
Yeast Cell ◽  
Virulence Factor ◽  
Enzyme Production ◽  
Peritoneal Macrophages ◽  
Systemic Mycosis ◽  
Melanin Production ◽  
Dimorphic Fungi ◽  
Laccase Enzyme

Paracoccidioidomycosis (PCM) is a granulomatous systemic mycosis caused by the thermo-dimorphic fungi of the genus Paracoccidioides. Melanin production by fungi can affect their pathogenesis and virulence. This study evaluates the production of melanin by different isolates of genus Paracoccidioides and examines how the presence of this polymer affects yeast cell phagocytosis, as well as laccase enzyme production. The results obtained showed that the isolates of genus Paracoccidioides: P. lutzii (Pb01, Pb66, ED01, Pb1578, and Pb8334), P. restrepiensis (PS3-Pb60855), P. brasiliensis (S1-Pb18), and P. americana (PS2-Pbcão) produce melanin in the presence of L-3,4-dihydroxyphenylalanine (L-DOPA). Phagocytosis assays were carried out with peritoneal macrophages from C57Bl/6 mice that were challenged with Pb18, Pb60855, and Pb01. We observed that melanin interferes with phagocytosis in the presence or absence of complement or heat-inactivated serum. This article confirms that different species of the genus Paracoccidioides produce melanin in different magnitudes and that the polymer functions as a virulence factor.

scholarly journals Peptidogalactomannan from Histoplasma capsulatum yeast cell wall: role of the chemical structure in recognition and activation by peritoneal macrophages

2021 ◽  
Author(s):  
Giulia Maria Pires dos Santos ◽  
Gustavo Ramalho Cardoso dos Santos ◽  
Mariana Ingrid Dutra da Silva Xisto ◽  
Rodrigo Rollin-Pinheiro ◽  
Andréa Regina de Souza Baptista ◽  
...  
Keyword(s):  
Cell Wall ◽  
Yeast Cell ◽  
Chemical Structure ◽  
Histoplasma Capsulatum ◽  
Peritoneal Macrophages ◽  
Yeast Cell Wall

scholarly journals Evaluation of laccases and melanization in clinical and environmental Cryptococcus neoformans samples by non-denaturing PAGE

2009 ◽  
Vol 58 (5) ◽  
pp. 563-566 ◽  
Author(s):  
Cristiane B. Pereira ◽  
Frank L. Bueno ◽  
Amanda L. T. Dias ◽  
Maísa R. P. L. Brigagão ◽  
Claudete R. Paula ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Enzyme Production ◽  
Laccase Activity ◽  
Opportunistic Pathogen ◽  
Clinical Strain ◽  
Melanin Production ◽  
Densitometry Analysis ◽  
Serotype B ◽  
Colour Quantification ◽  
Laccase Isoforms

The increased incidence of infections caused by the opportunistic pathogen Cryptococcus neoformans, which mainly affects immunocompromised patients but can also infect immunocompetent individuals, has needed additional studies on this micro-organism's pathogenicity and factors related to virulence, such as enzyme production, for a better understanding of the aetiology of cryptococcosis. The aim of this study was to verify the applicability of non-denaturing PAGE for analysis of laccases by quantification of the amount of melanin pigment produced by clinical and environmental strains of C. neoformans. After incubation of the gel with the substrate l-dopa, strains produced melanin spots of a bright brown to black colour. Quantification of these spots was performed by densitometry analysis and the amount of melanin produced was calculated and compared among the strains. All strains showed laccase activity. Serotype B strains showed a higher melanin intensity than serotype A strains. Over half of the clinical strains (56.2 %) showed the lowest melanin intensities, suggesting that melanin production may not be the main virulence factor against host defence. The clinical strain ICB 88 revealed two melanin spots on the gel, indicating the presence of two laccase isoforms. The environmental strains showed the highest values of melanin intensity, which may be related to previous exposure to environmental stress conditions.

scholarly journals Transcriptional Network of Multiple Capsule and Melanin Genes Governed by the Cryptococcus neoformans Cyclic AMP Cascade

2005 ◽  
Vol 4 (1) ◽  
pp. 190-201 ◽  
Author(s):  
Read Pukkila-Worley ◽  
Quincy D. Gerrald ◽  
Peter R. Kraus ◽  
Marie-Josée Boily ◽  
Matthew J. Davis ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Cryptococcus Neoformans ◽  
Glucose Deprivation ◽  
Melanin Production ◽  
Gene Encoding ◽  
Human Fungal Pathogen ◽  
Camp Pathway ◽  
Capsule Production ◽  
Capsule Assembly ◽  
Laccase Enzyme

ABSTRACT Cryptococcus neoformans is an opportunistic human fungal pathogen that elaborates several virulence attributes, including a polysaccharide capsule and melanin pigments. A conserved Gα protein/cyclic AMP (cAMP) pathway controls melanin and capsule production. To identify targets of this pathway, we used an expression profiling approach to define genes that are transcriptionally regulated by the Gα protein Gpa1. This approach revealed that Gpa1 transcriptionally regulates multiple genes involved in capsule assembly and identified two additional genes with a marked dependence on Gpa1 for transcription. The first is the LAC1 gene, encoding the laccase enzyme that catalyzes a rate-limiting step in diphenol oxidation and melanin production. The second gene identified (LAC2) is adjacent to the LAC1 gene and encodes a second laccase that shares 75% nucleotide identity with LAC1. Similar to the LAC1 gene, LAC2 is induced in response to glucose deprivation. However, LAC2 basal transcript levels are much lower than those for LAC1. Accordingly, a lac2 mutation results in only a modest delay in melanin formation. LAC2 overexpression suppresses the melanin defects of gpa1 and lac1 mutants and partially restores virulence of these strains. These studies provide mechanistic insights into the regulation of capsule and melanin production by the C. neoformans cAMP pathway and demonstrate that multiple laccases contribute to C. neoformans melanin production and pathogenesis.

scholarly journals Optimization, Production, Purification of Laccase Enzyme from Bacillus sp

2020 ◽  
Vol 2 (4) ◽  
pp. 35-43
Author(s):  
Nivedharshini Tamilvanan
Keyword(s):  
Rice Bran ◽  
Enzyme Production ◽  
Large Scale ◽  
Gel Filtration ◽  
Nitrogen Sources ◽  
Bacillus Sp ◽  
Biochemical Tests ◽  
Optimization Parameters ◽  
Microbial Screening ◽  
Laccase Enzyme

Laccase enzyme production is important and more beneficial for environment, because it has many roles like, involved in bioremediation, biodegradation, decolorization of environmental polluted dyes and pharmaceutical sector also. Production of laacse enzyme from bacillus sp as using of Agro waste (rice bran) as a substrate. The Agricultural soil sample was collected, after the sample were processed for the preliminary and biochemical tests to identification of Bacillus organism. The Guiacol inducer were used for microbial screening of laccase enzyme production. After that microbial screening, various optimization parameters (pH, Temperature, Inducers, carbon and nitrogen sources) are checked for that production of laccase enzyme in mass level. Based on that optimization the bulk fermentation (large scale) (solid state fermentation) were done as a rice bran substrate. The fermentation product was subjected to analyzed the physiochemical properties and purification based on that techniques of Gel filtration chromatography, Dialysis, Ammonium sulfate preciptation. The protein estimation of that product to analysed by lowry’s method.

scholarly journals Optimization of Laccase Enzyme Production by Amesia atrobrunnea A2: A First Report

2020 ◽  
Vol 17 (01) ◽  
pp. 65-72
Author(s):  
A.T. Thakkar ◽  
D.C. Pandya ◽  
S.A. Bhatt
Keyword(s):  
Enzyme Production ◽  
First Report ◽  
Laccase Enzyme

Characteristics of Pseudomonas aeruginosa Isolated From Whirlpools and Bathers

1985 ◽  
Vol 6 (10) ◽  
pp. 407-412 ◽  
Author(s):  
Anita K. Highsmith ◽  
Phuong Nhan Le ◽  
Rima F. Khabbaz ◽  
Van P. Munn
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Virulence Factor ◽  
Antimicrobial Susceptibility ◽  
Enzyme Production ◽  
Extracellular Enzyme ◽  
Skin Flora ◽  
Low Levels ◽  
Toxic Reactions ◽  
Susceptibility Patterns

AbstractPseudomonas aeruginosa is the most frequently isolated microorganism from whirlpool water and lesions associated with outbreaks of dermatitis and folliculitis related to whirlpool exposure. Strains were selected from 19 outbreaks of P. aeruginosa infections (1977 to 1983) associated with whirlpool use; they were examined to determine if the strains possessed unique virulence factors or characteristics that might aid in their selection in the environment.P. aeruginosa, 011, was the predominant serotype isolated from whirlpool water as well as from bathers with dermatitis or folliculitis, followed by serotypes 09, 04, and 03. Antimicrobial susceptibility patterns were similar for all strains. Strains of P. aeruginosa from bathers and water demonstrated statistically significant differences in extracellular enzyme production compared with control strains. P. aeruginosa, serotypes 09 and 011, were found to be sensitive to low levels of chlorine. These data suggest that, if adequate levels of free available chlorine are maintained, P. aeruginosa should have little opportunity to persist in whirlpools.A bather's risk of P. aeruginosa dermatitis or folliculitis appears to be affected primarily by three factors: 1) immersion in water colonized by P. aeruginosa, 2) skin hydration with altered skin flora, and 3) toxic reactions to extracellular enzyme or exotoxins produced by P. aeruginosa. Although a single virulence factor was not identified from the results of this study, there are some indications that the enzymes produced by these microorganisms play an important role in the pathogenesis of disease associated with whirlpool use.

scholarly journals pH Changes Have a Profound Effect on Gene Expression, Hydrolytic Enzyme Production, and Dimorphism in Saccharomycopsis fibuligera

2021 ◽  
Vol 12 ◽  
Author(s):  
Mohamed El-Agamy Farh ◽  
Najib Abdellaoui ◽  
Jeong-Ah Seo
Keyword(s):  
Gene Expression ◽  
Yeast Cell ◽  
Enzyme Production ◽  
Hydrolytic Enzyme ◽  
Cell Formation ◽  
Hyphal Growth ◽  
Acidic Ph ◽  
Hybrid Strain ◽  
Ph Change ◽  
Saccharomycopsis Fibuligera

Saccharomycopsis fibuligera is an amylolytic yeast that plays an important role within nuruk (a traditional Korean fermentation starter) used for the production of makgeolli (Korean rice wine), which is characterized by high acidity. However, the effect of pH change (neutral to acidic) on the yeast cell to hyphal transition and carbohydrate-hydrolyzing enzyme activities for S. fibuligera has not been investigated yet. In this study, S. fibuligera strains were cultured under the different pH conditions, and the effect on the enzyme production and gene expression were investigated. An acidic pH induced a hyphal transition from yeast cell of S. fibuligera KPH12 and the hybrid strain KJJ81. In addition, both strains showed a gradual decrease in the ability to degrade starch and cellulose as the pH went down. Furthermore, a transcriptome analysis demonstrated that the pH decline caused global expression changes in genes, which were classified into five clusters. Among the differentially expressed genes (DEGs) under acidic pH, the downregulated genes were involved in protein synthesis, carbon metabolism, and RIM101 and cAMP-PKA signaling transduction pathways for the yeast-hyphal transition. A decrease in pH induced a dimorphic lifestyle switch from yeast cell formation to hyphal growth in S. fibuligera and caused a decrease in carbohydrate hydrolyzing enzyme production, as well as marked changes in the expression of genes related to enzyme production and pH adaptation. This study will help to elucidate the mechanism of adaptation of S. fibuligera to acidification that occur during the fermentation process of makgeolli using nuruk.

scholarly journals Dimorphic Fungal Coinfection as a Cause of Chronic Diarrhea and Pancolitis

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Eduar A. Bravo ◽  
Arturo J. Zegarra ◽  
Alejandro Piscoya ◽  
José L. Pinto ◽  
Raúl E. de los Rios ◽  
...  
Keyword(s):  
North America ◽  
South America ◽  
Histoplasma Capsulatum ◽  
Chronic Diarrhea ◽  
Paracoccidioides Brasiliensis ◽  
Fungal Diseases ◽  
Systemic Mycosis ◽  
Gastrointestinal Involvement ◽  
Dimorphic Fungi ◽  
Tropical South America

Histoplasma capsulatumandParacoccidioides brasiliensisare dimorphic fungi that cause systemic mycosis mostly in tropical South America and some areas of North America. Gastrointestinal involvement is not uncommon among these fungal diseases, but coinfection has not previously been reported. We report a patient with chronic diarrhea and pancolitis caused by paracoccidioidomycosis and histoplasmosis.

scholarly journals Melanin Production and Laccase Mediated Oxidative Stress Alleviation During Fungal-fungal Interaction Among Basidiomycetes Fungi

2021 ◽  
Author(s):  
Samim Dullah ◽  
Dibya Jyoti Hazarika ◽  
Gunajit Goswami ◽  
Tanushree Borgohain ◽  
Alokesh Ghosh ◽  
...  
Keyword(s):  
Trametes Versicolor ◽  
Metabolite Profile ◽  
Laccase Production ◽  
Melanin Production ◽  
Potential Implication ◽  
Hyphal Morphology ◽  
Stress Related Genes ◽  
Laccase Enzyme ◽  
The One ◽  
Increased Activity

Abstract Fungal-fungal interaction often leads to the change in metabolite profile of both the interacting fungus which may have potential implication in industry or agriculture. In the present study, we performed two sets of fungal-fungal interaction - Trametes coccinea (F3) with Leiotrametes lactinea (F9) and Trametes coccinea (F3) with Trametes versicolor (F1) to understand the changes in the metabolite profile during the interaction process and how this process impacts the hyphal/mycelial morphology of the participating fungi. The metabolites produced during interaction of Trametes coccinea (F3) with Leiotrametes lactinea (F9) and Trametes coccinea (F3) with Trametes versicolor (F1) was analysed through Liquid Chromatography coupled to Mass Spectroscopy (LC-MS). Most of the metabolites secreted or produced during interaction are associated with defensive response. Further, visualization with scanning electron microscopy revealed that interaction between the tested fungi led to the change in the hyphal morphology of the one participating fungus. The bipartite fungal interaction resulted in the production of a dark brown colour pigment – melanin as confirmed by the LC-MS, FTIR and NMR analysis. Moreover, the fungal-fungal interaction also led to increase in the production of laccase, a group of multicopper oxidases involved in detoxification of toxic compounds. Further increased activity of superoxide dismutase, an enzyme that catalyzes the dismutation of the superoxide anion to hydrogen peroxide was also recorded during fungal– fungal interaction. Quantitative real-time PCR revealed upregulation of lcc1 (encoding a laccase enzyme) and few other stress related genes of T. versicolor during its hyphal interaction with T. coccinea, suggesting a direct correlation between laccase production and melanin production.

scholarly journals Laccase Affects the Rate of Cryptococcus neoformans Nonlytic Exocytosis from Macrophages

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Stefânia de Oliveira Frazão ◽  
Herdson Renney de Sousa ◽  
Lenise Gonçalves da Silva ◽  
Jéssica dos Santos Folha ◽  
Kaio César de Melo Gorgonha ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cryptococcus Neoformans ◽  
Laccase Activity ◽  
Severe Disease ◽  
Cell Types ◽  
Great Variability ◽  
Melanin Production ◽  
Content Type ◽  
Fungal Melanin ◽  
Laccase Enzyme

ABSTRACT Nonlytic exocytosis is a process in which previously ingested microbes are expelled from host phagocytes with the concomitant survival of both cell types. This process has been observed in the interaction of Cryptococcus spp. and other fungal cells with phagocytes as distant as mammalian, bird, and fish macrophages and ameboid predators. Despite a great amount of research dedicated to unraveling this process, there are still many questions about its regulation and its final benefits for host or fungal cells. During a study to characterize the virulence attributes of Brazilian clinical isolates of C. neoformans, we observed great variability in their rates of nonlytic exocytosis and noted a correlation between this process and fungal melanin production/laccase activity. Flow cytometry experiments using melanized cells, nonmelanized cells, and lac1Δ mutants revealed that laccase has a role in the process of nonlytic exocytosis that seems to be independent of melanin production. These results identify a role for laccase in virulence, independent of its role in pigment production, that represents a new variable in the regulation of nonlytic exocytosis. IMPORTANCE Cryptococcus neoformans is a yeast that causes severe disease, primarily in immunosuppressed people. It has many attributes that allow it to survive and cause disease, such as a polysaccharide capsule and the dark pigment melanin produced by the laccase enzyme. Upon infection, the yeast is ingested by cells called macrophages, whose function is to kill them. Instead, these fungal cells can exit from macrophages in a process called nonlytic exocytosis. We know that this process is controlled by both host and fungal factors, only some of which are known. As part of an ongoing study, we observed that C. neoformans isolates that produce melanin faster are more-frequent targets of nonlytic exocytosis. Further experiments showed that this is probably due to higher production of laccase, because fungi lacking this enzyme are nonlytically exocytosed less often. This shows that laccase is an important signal/regulator of nonlytic exocytosis of C. neoformans from macrophages.

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