RESUMO
We investigated the influence of corn steep liquor (CSL) and cassava waste water (CWW) as carbon and nitrogen sources on the morphology and production of biomass and chitosan by Mucor subtilissimus UCP 1262 and Lichtheimia hyalospora UCP 1266. The highest biomass yields of 4.832 g/L (M. subtilissimus UCP 1262) and 6.345 g/L (L. hyalospora UCP 1266) were produced in assay 2 (6% CSL and 4% CWW), factorial design 22, and also favored higher chitosan production (32.471 mg/g) for M. subtilissimus. The highest chitosan production (44.91 mg/g) by L. hyalospora (UCP 1266) was obtained at the central point (4% of CWW and 6% of CSL). The statistical analysis, the higher concentration of CSL, and lower concentration of CWW significantly contributed to the growth of the strains. The FTIR bands confirmed the deacetylation degree of 80.29% and 83.61% of the chitosan produced by M. subtilissimus (UCP 1262) and L. hyalospora (UCP 1266), respectively. M. subtilissimus (UCP 1262) showed dimorphism in assay 4-6% CSL and 8% CWW and central point. L. hyalospora (UCP 1266) was optimized using a central composite rotational design, and the highest yield of chitosan (63.18 mg/g) was obtained in medium containing 8.82% CSL and 7% CWW. The experimental data suggest that the use of CSL and CWW is a promising association to chitosan production.
Assuntos
Quitosana/metabolismo , Mucor/crescimento & desenvolvimento , Mucorales/crescimento & desenvolvimento , Acetilação , Biomassa , Carbono/metabolismo , Manihot/química , Mucor/metabolismo , Mucorales/metabolismo , Nitrogênio/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Zea mays/químicaRESUMO
The objective of the present study was to optimize parameters for the cultivation of Lichtheimia corymbifera (mesophilic) and Byssochlamys spectabilis (thermophilic) for the production of ß-glucosidases and to compare the catalytic and thermodynamic properties of the partially purified enzymes. The maximum amount of ß-glucosidase produced by L. corymbifera was 39 U/g dry substrate (or 3.9 U/mL), and that by B. spectabilis was 77 U/g (or 7.7 U/mL). The optimum pH and temperature were 4.5 and 55 °C and 4.0 and 50 °C for the enzyme from L. corymbifera and B. spectabilis, respectively. ß-Glucosidase produced by L. corymbifera was stable at pH 4.0-7.5, whereas the enzyme from B. spectabilis was stable at pH 4.0-6.0. Regarding the thermostability, ß-glucosidase produced by B. spectabilis remained stable for 1 h at 50 °C, and that from L. corymbifera was active for 1 h at 45 °C. Determination of thermodynamic parameters confirmed the greater thermostability of the enzyme produced by the thermophilic fungus B. spectabilis, which showed higher values of ΔH, activation energy for denaturation (Ea), and half-life t(1/2). The enzymes were stable in the presence of ethanol and were competitively inhibited by glucose. These characteristics contribute to their use in the simultaneous saccharification and fermentation of vegetable biomass.
Assuntos
Byssochlamys/enzimologia , Celulases/química , Proteínas Fúngicas/química , Mucorales/enzimologia , Byssochlamys/crescimento & desenvolvimento , Catálise , Celulases/antagonistas & inibidores , Celulases/isolamento & purificação , Técnicas de Cultura/métodos , Inibidores Enzimáticos/química , Etanol/química , Proteínas Fúngicas/antagonistas & inibidores , Proteínas Fúngicas/isolamento & purificação , Glucose/química , Concentração de Íons de Hidrogênio , Cinética , Mucorales/crescimento & desenvolvimento , Temperatura , TermodinâmicaRESUMO
Background: Enzyme production by solid state bioprocess (SSB) using residues as substrate for microorganisms is an alternative for costs reduction and to avoid their disposal into environment. The aim of this work was to evaluate the physiology of the fungus Lichtheimia ramosa in terms of microbial growth and production of amylases, β-glucosidases, carboxymethylcellulase (CMCase), and xylanases, via SSB, utilizing wastes of the Brazilian savannah fruits bocaiuva (Acrocomia aculeata), guavira (Campomanesia pubescens) and pequi (Caryocar brasiliense) as substrate at different temperatures (25, 30, and 35ºC) during 168 hrs. Results: Samples were taken every 24 hrs, which resulted in 8-points kinetic experiments to determine microbiological and enzymatic contents. The best substrate for β-glucosidase activity was pequi waste after 48 hrs at 30ºC (0.061 U/mL). For amylase activity, bocaiuva presented itself as the best substrate after 96 hrs at 30ºC (0.925 U/mL). CMCase activity was higher in guavira waste after 96 hrs at 35ºC (0.787 U/mL). However, the activity was more expressive for xylanase in substrate composed of bocaiuva residue after 144 hrs at 35ºC (1.802 U/mL). Conclusions: It was concluded that best growth condition for L. ramosa is at 35ºC for all substrates and that xylanase is the enzyme with more potential in SSB, considering the studied Brazilian savannah fruit wastes.
Assuntos
Xilosidases/metabolismo , Celulases/metabolismo , Amilases/metabolismo , Mucorales/enzimologia , Resíduos , Brasil , Reatores Biológicos , Frutas , Mucorales/crescimento & desenvolvimentoRESUMO
Thermophilic organisms produce thermostable enzymes, which have a number of applications, justifying the interest in the isolation of new thermophilic strains and study of their enzymes. Thirty-four thermophilic and thermotolerant fungal strains were isolated from soil, organic compost, and an industrial waste pile based on their ability to grow at 45 degrees C and in a liquid medium containing pectin as the only carbon source. Among these fungi, 50% were identified at the genus level as Thermomyces, Aspergillus, Monascus, Chaetomium, Neosartoria, Scopulariopsis, and Thermomucor. All isolated strains produced pectinase during solid-state fermentation (SSF). The highest polygalacturonase (PG) activity was obtained in the culture medium of thermophilic strain N31 identified as Thermomucor indicae-seudaticae. Under SSF conditions on media containing a mixture of wheat bran and orange bagasse (1:1) at 70% of initial moisture, this fungus produced the maximum of 120 U/ml of exo-PG, while in submerged fermentation (SmF) it produced 13.6 U/ml. The crude PG from SmF was more thermostable than that from SSF and exhibited higher stability in acidic pH.
Assuntos
Microbiologia Industrial , Mucorales/enzimologia , Mucorales/crescimento & desenvolvimento , Poligalacturonase/biossíntese , Brasil , Meios de Cultura , Fermentação , Temperatura Alta , Resíduos Industriais , Mucorales/classificação , Mucorales/isolamento & purificação , Pectinas/metabolismo , Microbiologia do Solo , Especificidade por SubstratoRESUMO
The fungi strains were tested in Bioscreen automated system to select the best nutritional source. Following, shaking submserse cultures were studied in media containing sole carbon or nitrogen source. The growth of these strains improved in media containing vegetable oil, with high concentration of lipids. The high concentration of γ-linolenic acid was obtained with M. circinelloides in culture containing sesame oil.
Linhagens de fungos foram testadas em sistema automatizado Bioscreen para selecionar melhor fonte nutricional. Em seguida, foram estudadas culturas submersas em meios contendo uma única fonte de carbono e de nitrogênio. As linhagens contendo alta concentração de lipídeos tiveram melhor crescimento em meio contendo óleos de gergelim ou de dendê. Maior concentração de ácido γ-linolênico foi obtida com M. circinelloides nas culturas em óleo de gergelim.
Assuntos
Ácidos Araquidônicos/análise , Ácidos Linolênicos/análise , Lipídeos/análise , Mucorales/crescimento & desenvolvimento , Óleos de Plantas/análise , Rhizopus/crescimento & desenvolvimento , Zigomicose , Microbiologia Industrial , Métodos , MétodosRESUMO
Since the first human infection by Saksenaea vasiformis in 1976 another 26 cases have been reported. Here is a report of a new case which involved an Ecuadorian adolescent who suffered serious burns after a car accident. It developed as a localized cutaneous infection which was successfully treated with surgical debridement and amphotericin B. This is the second report of this infection from South America and the third involving a burn patient. The previously reported 27 cases are reviewed.
Assuntos
Queimaduras/microbiologia , Dermatomicoses/etiologia , Mucorales/crescimento & desenvolvimento , Mucormicose/etiologia , Adolescente , Anfotericina B/uso terapêutico , Queimaduras/tratamento farmacológico , Queimaduras/cirurgia , Dermatomicoses/tratamento farmacológico , Humanos , Masculino , Microscopia Eletrônica de Varredura/métodos , Microscopia de Polarização/métodos , Mucormicose/tratamento farmacológicoRESUMO
Ornithine decarboxylase (ODC) is the first enzyme in polyamine biosynthesis in numerous living organisms, from bacteria to mammalian cells. Its control is under negative feedback regulation by the end products of the pathway. In dimorphic fungi, ODC activity and therefore polyamine concentrations are related to the morphogenetic process. From the fission yeast Schizosaccharomyces pombe to human, polyamines induce antizyme synthesis which in turn inactivates ODC. This is hydrolyzed by the 26S proteasome without ubiquitination. The regulatory mechanism of antizyme on polyamines is conserved, although to date no antizyme homology has been identified in some fungal species. The components that are responsible for regulating polyamine levels in cells and the current knowledge of ODC regulation in dimorphic fungi are presented in this review. ODC degradation is of particular interest because inhibitors of this pathway may lead to the discovery of novel antifungal drugs.
Assuntos
Proteínas Fúngicas/metabolismo , Ornitina Descarboxilase/metabolismo , Peptídeo Hidrolases/metabolismo , Complexo de Endopeptidases do Proteassoma , Proteínas/metabolismo , Animais , Proteínas de Drosophila/metabolismo , Ativação Enzimática , Retroalimentação Fisiológica , Humanos , Mamíferos/metabolismo , Morfogênese , Mucorales/enzimologia , Mucorales/crescimento & desenvolvimento , Paracoccidioides/enzimologia , Paracoccidioides/crescimento & desenvolvimento , Poliaminas/metabolismo , Ratos , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Especificidade da EspécieAssuntos
Dermatomicoses/diagnóstico , Mucormicose/diagnóstico , Adulto , Anfotericina B/uso terapêutico , Antifúngicos/uso terapêutico , Dermatomicoses/tratamento farmacológico , Dermatomicoses/cirurgia , Quimioterapia Combinada , Fluconazol/uso terapêutico , Humanos , Masculino , Mucorales/crescimento & desenvolvimento , Mucormicose/tratamento farmacológico , Mucormicose/cirurgia , Coxa da Perna/parasitologia , Coxa da Perna/cirurgiaRESUMO
Diamino butanone (DAB), a competitive inhibitor of ornithine decarboxylase (ODC) a key enzyme in polyamine biosynthesis, inhibited the yeast to hyphae transition in Mucor rouxii, induced by transfer from anaerobiosis to aerobiosis, but not the opposite phenomenon. Addition of DAB to anaerobic yeast cells brought about a decrease in ODC and polyamine levels. In these conditions, the aerobic shift produced only a weak increase in ODC activity and no change in polyamine levels. DAB also blocked phorogenesis in M. rouxii and in Phycomyces blakesleeanus. At the effective concentrations DAB did not affect cell growth of either fungus. It is suggested that low, constant levels of ODC and polyamines are necessary for cell growth, and that high transient levels are required during the differentiative steps. DAB, at the concentrations used, affects this last process, but does not interfere with the maintenance level of polyamines.
Assuntos
Mucorales/efeitos dos fármacos , Putrescina/análogos & derivados , Diferenciação Celular/efeitos dos fármacos , Mucor/efeitos dos fármacos , Mucor/crescimento & desenvolvimento , Mucor/metabolismo , Mucorales/crescimento & desenvolvimento , Mucorales/metabolismo , Inibidores da Ornitina Descarboxilase , Phycomyces/efeitos dos fármacos , Phycomyces/crescimento & desenvolvimento , Phycomyces/metabolismo , Poliaminas/biossíntese , Putrescina/farmacologiaRESUMO
The term mucormycosis encompasses a distinctive group of infections caused by fungi belonging to genera within the taxonomic order Mucorales, usually Rhizopus, Absidia, Mortierella, and Mucor. These fungi are widespread in nature, subsisting on decaying vegetation and diverse organic materials. Although the fungi and spores of Mucorales show minimal intrinsic pathogenicity toward normal persons, they can initiate aggressive and fulminant infections under certain clinical conditions. Ketoacidotic diabetics are predisposed to rhinocerebral mucormycosis, whereas patients with leukemia or lymphoma are susceptible to pulmonary or disseminated infections. These infections, which often result in devastating long-diagnostic and therapeutic challanges