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1.
Cell Mol Biol (Noisy-le-grand) ; 67(1): 165-170, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-34817351

RESUMO

In current study, Maize (Zea mays L.) husk leave extracts were appraised for biological activities such as cytotoxicity, antidiabetic, antioxidant and antimicrobial. Maceration was performed to collect various fractions of husk leave extracts using a pool of solvents i.e., n-hexane, chloroform, ethyl acetate, butanol and methanol. Antioxidant potential was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and linoleic acid oxidation assay, using butylated hydroxy toluene (BHT) as a positive control. Total phenolic and flavonoid contents were found to be 18.47-425.11 mg/100 g GAE and 5.83-16.72 mg/100 g CE, respectively. The DPPH scavenging assay was exhibited in the range of 76.36 to 88.53%. The percentage inhibition in linoleic acid oxidation was found from 10.16 to 79.51%. Significant antimicrobial activity was demonstrated by husk leaf extracts against bacterial strains and fungal strains using disc diffusion and minimum inhibitory concentration (MIC) method. Amylase alpha assay was employed to analyze the antidiabetic activity which ranged between 9.52-24.81%. Cytotoxicity was evaluated by % age lysis (0.35-9.54%), while thrombolytic activity ranged between 7.67 to 31.27%. The results presented in this study revealed that maize (Zea mays L.) husk leaf extracts can be a valuable source of biologically active compounds and may be consumed as a source of potent herbal medicine in pharmaceuticals.


Assuntos
Antioxidantes/farmacologia , Hipoglicemiantes/farmacologia , Folhas de Planta/química , Zea mays/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/fisiologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Hemólise/efeitos dos fármacos , Humanos , Hipoglicemiantes/química , Testes de Sensibilidade Microbiana/métodos , Extratos Vegetais/química , Extratos Vegetais/farmacologia
2.
Biosystems ; 209: 104507, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34403720

RESUMO

Mycelium networks are promising substrates for designing unconventional computing devices providing rich topologies and geometries where signals propagate and interact. Fulfilling our long-term objectives of prototyping electrical analog computers from living mycelium networks, including networks hybridised with nanoparticles, we explore the possibility of implementing Boolean logical gates based on electrical properties of fungal colonies. We converted a 3D image-data stack of Aspergillus niger fungal colony to an Euclidean graph and modelled the colony as resistive and capacitive (RC) networks, where electrical parameters of edges were functions of the edges' lengths. We found that and, or and and-not gates are implementable in RC networks derived from the geometrical structure of the real fungal colony.


Assuntos
Aspergillus niger/fisiologia , Simulação por Computador , Modelos Biológicos , Micélio/fisiologia , Esporos Fúngicos/fisiologia , Aspergillus niger/citologia , Contagem de Colônia Microbiana , Estimulação Elétrica , Microscopia Confocal , Microscopia de Fluorescência
3.
Pak J Pharm Sci ; 34(1): 151-156, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34248014

RESUMO

The present research study investigates the phytochemical and pharmacological importance of Bromus pectinatus. Qualitative phytochemical analysis of this plant was carried out to use standard method for the presence of various bioactive constituents. Results showed the ethanolic extract contain natural product such as steroids, alkaloids, tannins, coumarin, saponins, flavonoids and phenols. These compounds play a key role to reducing various disease and microbial inhibition. The ethanolic extract also showed the antimicrobial and antifugal activity against different pathogenic bacterial strains e.g Escherichia coli, Micrococus leutus, Protus vulgarus, and Kelebsela pneumona and three fungal strains Aspergillus fumigatus, Aspergillus flavous, Aspergillus niger. The antioxidant assay was performed as % inhibition of DPPH (1, 1-diphenyl-2-picryl-hydrazyl) free radicals. The plant extract has more antioxidant activity as compared to ascorbic acid. The maximum concentration (800µg/ml) is the most effective of all. The plant extract showed the high cytotoxicity activity against Brine shrimp. Moreover, the plant extract exhibited allelopathic effect on different growth parameters of wheat plant mostly at higher concentration. These results indicate that the BPEE have a potential broad-spectrum antimicrobial, cytotoxic, antioxidant and phytotoxic activity due to the presence of bioactive compounds.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Bromus , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Animais , Anti-Infecciosos/isolamento & purificação , Antioxidantes/isolamento & purificação , Artemia , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/fisiologia , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Testes de Sensibilidade Microbiana/métodos , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/isolamento & purificação
4.
Ultrason Sonochem ; 76: 105636, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34192660

RESUMO

For the first time, this study addresses the intensification of supercritical carbon dioxide (SC-CO2) treatments using high-power ultrasound (HPU) for the inactivation of fungal (Aspergillus niger) and bacterial (Clostridium butyricum) spores in oil-in-water emulsions. The inactivation kinetics were analyzed at different pressures (100, 350 and 550 bar) and temperatures (50, 60, 70, 80, 85 °C), depending on the microorganism, and compared to the conventional thermal treatment. The inactivation kinetics were satisfactorily described using the Weibull model. Experimental results showed that SC-CO2 enhanced the inactivation level of both spores when compared to thermal treatments. Bacterial spores (C.butyricum) were found to be more resistant to SC-CO2 + HPU, than fungal (A.niger) ones, as also observed in the thermal and SC-CO2 treatments. The application of HPU intensified the SC-CO2 inactivation of C.butyricum spores, e.g. shortening the total inactivation time from 10 to 3 min at 85 °C. However, HPU did not affect the SC-CO2 inactivation of A.niger spores. The study into the effect of a combined SC-CO2 + HPU treatment has to be necessarily extended to other fungal and bacterial spores, and future studies should elucidate the impact of HPU application on the emulsion's stability.


Assuntos
Dióxido de Carbono/farmacologia , Lipídeos/química , Viabilidade Microbiana/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos , Esporos Fúngicos/efeitos dos fármacos , Ondas Ultrassônicas , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/fisiologia , Clostridium butyricum/efeitos dos fármacos , Clostridium butyricum/fisiologia , Emulsões , Esporos Bacterianos/fisiologia , Esporos Fúngicos/fisiologia
5.
J Appl Microbiol ; 130(2): 424-438, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32686259

RESUMO

AIMS: To ascertain the effectiveness of Aspergillus niger, Trichoderma harzianum, Pochonia chlamydosporia, Bacillus subtilis and Pseudomonas fluorescens against rice root-knot nematode, Meloidogyne graminicola, and to optimize their application methods. METHODS AND RESULTS: The relative effectiveness of five indigenous biocontrol agents (BCA) against M. graminicola on rice cv. PS-5 was tested initially in pot culture. The BCAs, A. niger, P. chlamydosporia and P. fluorescens proved more effective, and significantly reduced the nematode disease. It is hypothesized that success of a biocontrol module may vary with the BCA and application methods. Hence, the effectiveness of the above three BCAs as well as seven different treatment schemes were evaluated in naturally infested farmer's fields during 2 consecutive years. In nematode-infested plots without any BCA treatments, terminal galls formed on the roots, and plants suffered a 19-31% decrease in the growth and yield. The treatments with P. chlamydosporia or A. niger through root-dip (RD) plus one soil application (SA) at 15 days after planting were found to be highly effective against the nematode. CONCLUSIONS: Relatively greater nematode control was achieved with RD plus two SAs (15 + 30 DAP) but statistically the effect was on par with RD + one SA at 15 DAP. These treatments significantly reduced galling (22-25%), egg mass production (21-29%) and reproduction factor (63-70%) of M. graminicola, and subsequently increased the grain yield (11-21%). SIGNIFICANCE AND IMPACT OF THE STUDY: Application methods enhanced the effectiveness of BCAs against M. graminicola. The RD plus one SA at 15 DAP proved to be most effective treatment to control root-knot disease in rice. Use of multiple treatments (root dip and SA) appears cumbersome, but in view of effectiveness and limitation of chemical control in rice paddies, farmers may adopt the above module that may lead to 11-21% yield improvement.


Assuntos
Oryza/parasitologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/prevenção & controle , Tylenchoidea/efeitos dos fármacos , Animais , Aspergillus niger/fisiologia , Agentes de Controle Biológico/classificação , Agentes de Controle Biológico/farmacologia , Hypocreales/fisiologia , Oryza/crescimento & desenvolvimento , Doenças das Plantas/parasitologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/parasitologia , Reprodução/efeitos dos fármacos , Tylenchoidea/fisiologia
6.
Food Chem ; 334: 127560, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711271

RESUMO

Post-fermented Pu-erh tea (PFPT) is a microbially-fermented tea with distinct sensory qualities and multiple health benefits. Aspergillus are the dominant fungi in the fermentation and the main contributors to the characteristics of PFPT, so their underlying functions warrant detailed study. Here, tea leaves were fermented by Aspergillus niger, Aspergillus tamarii and Aspergillus fumigatus, and resulting samples (designated as Asn, Ast and Asf, respectively) were analyzed by proteomic and metabolomic methods. Changes to the composition of flavonoids, glycerophospholipids, organo-oxygen compounds and fatty acids resulting from Aspergillus fermentation were observed. Carbohydrate-active enzymes, e.g., endoglucanases and cellulases, for degradation of cellulose, starch, lignin, pectin, xylan and xyloglucan were identified. Glycoside hydrolase, glycosyltransferases, tannase, laccases, vanillyl-alcohol oxidases and benzoquinone reductase were identified and hypothesized to catalyze hydrolysis, oxidation, polymerization and degradation of phenolic compounds. Together, functions of Aspergillius were demonstrated as production of enzymes to change concentrations and compositions of metabolites in tea leaves.


Assuntos
Aspergillus/fisiologia , Camellia sinensis/microbiologia , Enzimas/metabolismo , Folhas de Planta/microbiologia , Chá , Aspergillus/enzimologia , Aspergillus fumigatus/enzimologia , Aspergillus fumigatus/fisiologia , Aspergillus niger/enzimologia , Aspergillus niger/fisiologia , Metabolismo dos Carboidratos , Fermentação , Flavonoides/análise , Flavonoides/metabolismo , Microbiologia de Alimentos/métodos , Proteínas Fúngicas/metabolismo , Glicerofosfolipídeos/metabolismo , Metabolômica/métodos , Fenóis/análise , Fenóis/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo , Proteômica/métodos , Chá/química , Chá/metabolismo , Chá/microbiologia
7.
Mar Drugs ; 18(12)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33371380

RESUMO

In recent years, due to an expansion of antibiotic-resistant microorganisms, there has been growing interest in biodegradable and antibacterial polymers that can be used in selected biomedical applications. The present work describes the synthesis of antimicrobial polylactide-copper alginate (PLA-ALG-Cu2+) composite fibers and their characterization. The composites were prepared by immersing PLA fibers in aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the polylactide fibers with Cu(II) ions to yield PLA-ALG-Cu2+ composite fibers. The composites, so prepared, were characterized by scanning electron microscopy (SEM), UV/VIS transmittance and attenuated total reflection Fourier-transform infrared spectroscopy ATR-FTIR, and by determination of their specific surface area (SSA), total/average pore volumes (through application of the 5-point Brunauer-Emmett-Teller method (BET)), and ability to block UV radiation (determination of the ultraviolet protection factor (UPF) of samples). The composites were also subjected to in vitro antimicrobial activity evaluation tests against colonies of Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria and antifungal susceptibility tests against Aspergillus niger and Chaetomium globosum fungal mold species. All the results obtained in this work showed that the obtained composites were promising materials to be used as an antimicrobial wound dressing.


Assuntos
Alginatos/química , Alginatos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Poliésteres/química , Poliésteres/farmacologia , Alginatos/análise , Anti-Infecciosos/análise , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/fisiologia , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Testes de Sensibilidade Microbiana/métodos , Microscopia Eletrônica de Varredura/métodos , Poliésteres/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia
8.
J Invertebr Pathol ; 171: 107341, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32057750

RESUMO

Phenoloxidase (PO) is a key enzyme in the melanization process involved in elimination of pathogens in insects. The PO system is rapidly activated in response to pathogen recognition. Inhibition of PO activity can be a way to avoid immune response and increase infection effectiveness. In this study, the effects of inoculation of Galleria mellonella larvae with Aspergillus niger α-1,3-glucan and conidia on PO activity in hemolymph are analyzed in comparison with the effects of ß-1,3/1,6-glucan inoculation. Our results indicate that α-1,3-glucan, a fungal cell wall polysaccharide, can play a role of a virulence factor involved in inhibition of the insect PO system.


Assuntos
Aspergillus niger/fisiologia , Glucanos/fisiologia , Proteínas de Insetos/antagonistas & inibidores , Monofenol Mono-Oxigenase/antagonistas & inibidores , Mariposas/microbiologia , Fatores de Virulência/fisiologia , Animais , Larva/crescimento & desenvolvimento , Larva/microbiologia , Mariposas/crescimento & desenvolvimento , Esporos Fúngicos/fisiologia
9.
Antonie Van Leeuwenhoek ; 113(5): 697-706, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31919791

RESUMO

It was recently demonstrated that apical compartments of Aspergillus niger hyphae are self-sustaining in growth. This was shown by assessing the growth rate of individual hyphae before and after dissection of the second compartment. Using the same methodology, it is here demonstrated that single apical compartments of the septate fungi Penicillium chrysogenum and Schizophyllum commune as well as the 500-µm-apical region of the non-septate fungus Rhizopus stolonifer are also self-sustaining in growth. In contrast, single 2nd compartments (obtained by dissection of the first and third compartment) of the septate fungi or the region between 500 and 1000 µm from tips of R. stolonifer were severely impacted in their growth rate. In addition, it is shown that existing or newly formed branches originating from the 2nd compartments function as a backup system for hyphal growth when the apical part of the hypha of the three studied fungi is damaged. Together, it is concluded that the apical compartments/zones of the studied fungi are self-sustaining in growth. In contrast, the subapical region is not self-sustaining but functions as a backup once the apical zone is damaged. This back up system is relevant in nature because the apices of hyphae are the first to be exposed to (a)biotic stress conditions when entering an unexplored substrate.


Assuntos
Aspergillus niger/crescimento & desenvolvimento , Hifas/crescimento & desenvolvimento , Adaptação Fisiológica , Aspergillus niger/fisiologia , Compartimento Celular , Estresse Fisiológico
10.
J Basic Microbiol ; 60(3): 231-242, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31856361

RESUMO

Fungal biofilm is ubiquitous in natural environment. The major constituent of fungal biofilm other than biomass is the extracellular matrix (ECM), in which fungal hyphae are embedded. Physical properties of biofilms such as attachment, mechanical strength, and antibiotic resistance can be attributed to ECM. The present work probes various stages of biofilm formation by filamentous manglicolous fungus Aspergillus niger BSC-1. The spectroscopic analysis revealed that with an increase in incubation time the biofilm formation was significantly increased (p < .0001) up to 36 h. Scanning electron micrograph and confocal micrograph depicted the development of fungal biofilm comprising of six stages, that is, (a) adsorption, (b) active attachment, (c) germling and monolayer formation, (d) hyphal development and formation of ECM, (e) maturation of ECM, and (f) dispersal of spores. At maturation stage, thickness of biofilm was observed upto approximately 15 µm. Approximately, 8.1 mg of ECM materials were extracted from 20 ml of broth culture using ethanol precipitation method. Furthermore, attenuated total reflectance Fourier-transformed infrared spectroscopic analysis exhibited peaks at 3,398, 2,930, 1,571, 1,391, 1,092, 977 cm-1 which confirmed the presence of protein, carbohydrate, and lipid in the biofilm-associated matrix.


Assuntos
Aspergillus niger/fisiologia , Biofilmes/crescimento & desenvolvimento , Matriz Extracelular de Substâncias Poliméricas/química , Matriz Extracelular de Substâncias Poliméricas/ultraestrutura , Microscopia Confocal , Microscopia Eletrônica de Varredura , Áreas Alagadas
11.
Braz J Microbiol ; 50(4): 1091-1098, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31515726

RESUMO

Ochratoxin A (OTA) is a mycotoxin found in several agricultural commodities. Produced by Aspergillus spp., it is nephrotoxic and hepatotoxic and can be carcinogenic. Preventive measures are preventing fungal growth and OTA production. In this study, fungal strains (Rhizopus oryzae, Lichtheimia ramosa, Aspergillus westerdijkiae, Aspergillus niger, Aspergillus tamarii, Aspergillus sp., and Aspergillus fumigatus) isolated from coffee beans were identified for their abilities to inhibit the growth of Aspergillus ochraceus, Aspergillus westerdijkiae, Aspergillus carbonarius, and Aspergillus niger, and OTA production. All fungi strains tested were able to inhibit growth of the four Aspergillus species and OTA production, where A. niger showed the best results in both tests. L. ramosa showed the lowest growth-reducing potential, while the other fungal strains had a growth-reducing potential higher than 70% against all Aspergillus species tested. Regarding OTA production, L. ramosa and Aspergillus sp. completely inhibited the mycotoxin production by A. ochraceus and non-toxigenic strain A. niger completely inhibited OTA production by A. niger. Our findings indicate that the strains tested can be used as an alternative means to control growth of OTA-producing fungi and production of the mycotoxin in coffee beans.


Assuntos
Antibiose , Aspergillus niger/crescimento & desenvolvimento , Aspergillus niger/metabolismo , Coffea/microbiologia , Fungos/fisiologia , Ocratoxinas/biossíntese , Sementes/microbiologia , Aspergillus niger/fisiologia , Contaminação de Alimentos/prevenção & controle , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Filogenia
12.
Sci Rep ; 9(1): 12791, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488879

RESUMO

Among opportunistically pathogenic filamentous fungi of the Aspergillus genus, Aspergillus fumigatus stands out as a drastically more prevalent cause of infection than others. Utilizing the zebrafish embryo model, we applied a combination of non-invasive real-time imaging and genetic approaches to compare the infectious development of A. fumigatus with that of the less pathogenic A. niger. We found that both species evoke similar immune cell migratory responses, but A. fumigatus is more efficiently phagocytized than A. niger. Though efficiently phagocytized, A. fumigatus conidia retains the ability to germinate and form hyphae from inside macrophages leading to serious infection even at relatively low infectious burdens. By contrast, A. niger appears to rely on extracellular germination, and rapid hyphal growth to establish infection. Despite these differences in the mechanism of infection between the species, galactofuranose mutant strains of both A. fumigatus and A. niger display attenuated pathogenesis. However, deficiency in this cell wall component has a stronger impact on A. niger, which is dependent on rapid extracellular hyphal growth. In conclusion, we uncover differences in the interaction of the two fungal species with innate immune cells, noticeable from very early stages of infection, which drive a divergence in their route to establishing infections.


Assuntos
Aspergilose/veterinária , Aspergillus fumigatus/fisiologia , Aspergillus niger/fisiologia , Doenças dos Peixes/microbiologia , Fagocitose , Peixe-Zebra/microbiologia , Animais , Aspergilose/microbiologia , Aspergillus fumigatus/imunologia , Aspergillus fumigatus/patogenicidade , Aspergillus niger/imunologia , Aspergillus niger/patogenicidade , Ensaios de Migração de Leucócitos , Modelos Animais de Doenças , Doenças dos Peixes/imunologia , Leucócitos/imunologia , Macrófagos/microbiologia , Especificidade da Espécie , Esporos Fúngicos/crescimento & desenvolvimento , Técnicas de Cultura de Tecidos , Peixe-Zebra/imunologia
13.
Anal Bioanal Chem ; 411(26): 6857-6866, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31420709

RESUMO

We show an alternative way to visualize time course NMR data without the application of multivariate data analysis, based on the temporal change of the metabolome of hazelnuts after mold infestation. Fresh hazelnuts were inoculated with eight different natural mold species and the growth was studied over a period of 14 days. The data were plotted in a color-coded scheme showing metabolic changes as a function of chemical shift, which we named signal pattern plot. This plot graphically displays alteration (trend) of a respected signal over time and allows visual interpretation in a simple manner. Changes are compared with a reference sample stored under identical conditions as the infected nuts. The plot allows, at a glance, the recognition of individual landmarks specific to a sample group as well as common features of the spectra. Each sample reveals an individual signal pattern. The plot facilitates the recognition of signals that belong to biological relevant metabolites. Betaine and five signals were identified that specifically changed upon mold infestation. Graphical abstract.


Assuntos
Corylus/metabolismo , Corylus/microbiologia , Metaboloma , Metabolômica/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Aspergillus niger/fisiologia , Betaína/análise , Betaína/metabolismo , Corylus/química , Fungos/fisiologia , Interações Hospedeiro-Patógeno , Doenças das Plantas/microbiologia
14.
Bioelectrochemistry ; 129: 10-17, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31075534

RESUMO

In this study, the corrosion behavior of 7075-T6 aluminum alloy in a high salinity environment containing Aspergillus niger was investigated using high-performance liquid chromatography tandem mass spectrometry, gas chromatography, surface analysis and electrochemical measurement. Results demonstrated that uniform and localized corrosion rates of the alloy in the presence of A. niger were approximately 3.7 and 22.4 times, respectively, of that in the absence A. niger. This higher corrosion rate was attributed to accelerated anode and cathode reactions from the actions of A. niger biofilm. Additionally, organic acid corrosion caused by the presence of A. niger was confirmed to be the main cause for the corrosion of aluminum alloy.


Assuntos
Ligas/química , Alumínio/química , Aspergillus niger/fisiologia , Biofilmes/crescimento & desenvolvimento , Corrosão , Técnicas Eletroquímicas , Eletrodos/microbiologia , Salinidade , Propriedades de Superfície
15.
Can J Microbiol ; 65(9): 653-667, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31059650

RESUMO

We continued our study of high-molecular-mass proteases (HMMPs) using several strains of the genus Trichoderma, and other filamentous fungi (Botrytis cinerea, Aspergillus niger, Fusarium culmorum, and Penicillium purpurogenum). We found that five Trichoderma strains secreted HMMPs into the media after induction with bovine serum albumin. Botrytis cinerea and F. culmorum secreted proteases in the absence of inducer, while A. niger or P. purpurogenum did not secrete proteolytic activity (PA). The activity of HMMPs secreted by or intracellularly located in Trichoderma spp. represents the predominant part of cellular PA, according to zymogram patterns. This observation allowed the study of HMMPs' physiological role(s) independent from the secretion. In studying conidiation, we found that illumination significantly stimulated PA in Trichoderma strains. In the T. atroviride IMI 206040 strain, we demonstrated that this stimulation is dependent on the BLR1 and BLR2 receptors. No stimulation of PA was observed when mechanical injury was used as an elicitor of conidiation. Compounds used as inhibitors or activators of conidiation exerted no congruent effects on both PA and conidiation. These results do not favour a direct role of HMMPs in conidiation. Probably, HMMP activity may be involved in the process of the activation of metabolism during vegetative growth, differentiation, and aging-related processes.


Assuntos
Peptídeo Hidrolases/metabolismo , Trichoderma/enzimologia , Aspergillus niger/enzimologia , Aspergillus niger/fisiologia , Botrytis/enzimologia , Botrytis/fisiologia , Proteínas Fúngicas/metabolismo , Fusarium/enzimologia , Fusarium/fisiologia , Penicillium/enzimologia , Penicillium/fisiologia , Proteólise , Esporos Fúngicos , Trichoderma/fisiologia
16.
Artigo em Inglês | MEDLINE | ID: mdl-30935098

RESUMO

Filtering nonwovens that constitute the base material for filtering facepiece respirators (FFRs) used for the protection of the respiratory system against bioaerosols may, in favourable conditions, promote the development of harmful microorganisms. There are no studies looking at the impact that different types of filtering nonwovens have on microorganism survival, which is an important issue for FFR producers and users. Five commercial filtering nonwovens manufactured using diverse textile technologies (i.e., needle-punching, melt-blown, spun-bonding) with different structural parameters and raw material compositions were used within our research. The survival of microorganisms on filtering nonwovens was determined for E. coli, S. aureus, B. subtilis bacteria; C. albicans yeast and A. niger mould. Samples of nonwovens were collected immediately after inoculum application (at 0 h) and after 4, 8, 24, 48, 72, and 96 h of incubation. The tests were carried out in accordance with the AATCC 100-1998 method. Survival depended strongly on microorganism species. E. coli and S. aureus bacteria grew the most on all nonwovens tested. The structural parameters of the nonwovens tested (mass per unit area and thickness) and contact angle did not significantly affect microorganism survival.


Assuntos
Aspergillus niger/fisiologia , Bacillus subtilis/fisiologia , Candida albicans/fisiologia , Escherichia coli/fisiologia , Dispositivos de Proteção Respiratória/microbiologia , Staphylococcus aureus/fisiologia , Aspergillus niger/crescimento & desenvolvimento , Bacillus subtilis/crescimento & desenvolvimento , Candida albicans/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Filtração/instrumentação , Humanos , Exposição Ocupacional/prevenção & controle , Staphylococcus aureus/crescimento & desenvolvimento
17.
Trop Anim Health Prod ; 51(6): 1383-1391, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30706333

RESUMO

This study was conducted to determine intake and growth performance of broiler chicks fed with Jatropha curcas kernel meal physico-chemically and biologically processed. The feed experiment lasted for 7 days with 20-day-old Ross 308 strain unsexed broiler chicks. Two dietary treatments were given each to ten animals, according to a complete randomized design. Kernels, manually obtained from J. curcas seed, were defatted, heated, and fermented with a strain of Aspergillus niger and oven-dried, in order to obtain the treated jatropha kernel meal. This latter was used to replace one third of a groundnut meal premix which was then incorporated in a commercial diet to warrant iso-nitrogenous and iso-caloric characteristics of the diets. Data collected were analyzed according to ANOVA procedure. The results revealed that the animals that received the diet incorporating jatropha kernel meal had numerically higher live weight (156.1 vs. 152.7 g/animal) (P > 0.05) and average daily weight gain (12.3 vs. 11.7 g/day/animal) (P > 0.05) than the control ones, at the end of experiment. The average daily feed intake was the same for the two groups of animals (23.2 g/day/animal) (P > 0.05) with a similar feed conversion ratio (2.0 vs. 2.1 respectively for the jatropha group and the control group). The survival rate, at the end of the experiment, was 100% for the two groups of animals. Physico-chemically and biologically processed Jatropha curcas kernel could be an interesting by-product for poultry feeding.


Assuntos
Ração Animal/análise , Aspergillus niger/fisiologia , Galinhas , Dieta/veterinária , Jatropha/química , Fenômenos Fisiológicos da Nutrição Animal , Animais , Fermentação , Temperatura Alta , Distribuição Aleatória , Sementes/química , Aumento de Peso
18.
Mater Sci Eng C Mater Biol Appl ; 97: 486-497, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30678936

RESUMO

A method was developed for the liquid exfoliation of molybdenum disulfide (MoS2) from its bulk materials using ultrasound in aqueous phase with the assistance of chitosan (CS) and silver nanoparticles (Ag NPs) for effective loading of a variety of therapeutic molecules. The characterization results revealed that the as-made chemically-exfoliated MoS2 nanosheets had an average thickness of ∼10 nm. The new material, CS and Ag NPs-modified MoS2 (MoS2-CS-Ag), showed highly effective antifungal activities against Saccharomyces uvarum and Aspergillus niger. The Ag NPs-loaded MoS2 nanosheets achieved outstanding antifungal effect by inhibiting fungal growth both in vitro and in vivo. Notably, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis of spore morphological changes caused by MoS2-CS-Ag treatment reveal that it may directly cause the cell death. The result of the analysis of the application of MoS2-CS-Ag as an antifungal for fruits also demonstrated the MoS2-CS-Ag protective properties against fungi. The excellent film-forming ability of CS has been shown to contribute to the effectiveness of MoS2-CS-Ag in preserving the freshness of fruits, exhibited in four chemical quality sections: Vc, total carbohydrate, weight loss, and titratable acidity in fruit preservation application assay. The present study reports a new and exciting insight in a multi-functional drug carrier for protecting postharvest fruit.


Assuntos
Antifúngicos/química , Quitosana/química , Dissulfetos/química , Nanopartículas Metálicas/química , Molibdênio/química , Prata/química , Animais , Antifúngicos/síntese química , Antifúngicos/farmacologia , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/fisiologia , Parede Celular/efeitos dos fármacos , Frutas/efeitos dos fármacos , Frutas/microbiologia , Rim/efeitos dos fármacos , Rim/patologia , Masculino , Malus/efeitos dos fármacos , Malus/microbiologia , Nanopartículas Metálicas/toxicidade , Camundongos , Camundongos Nus , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Saccharomyces/efeitos dos fármacos
19.
Sci Rep ; 9(1): 591, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679719

RESUMO

Heterodera glycines is the most pervasive soybean pests worldwide. Biocontrol provides a strategy to sustainably control nematodes. In this study, 22 fungal isolates were obtained and identified from cysts of Heterodera spp. Among them, Aspergillus niger NBC001 showed high nematicidal activity against H. glycines. The 2-fold dilution of NBC001 culture filtrate caused 89% mortality of second-stage juveniles and inhibited more than 98% of egg hatching in vitro. In both pot and field experiments, the numbers of H. glycines cysts in soybean seedlings dressed with the the 5-fold concentrated culture filtrate of NBC001 were significantly reduced by 43% and 28%, respectively. In addition, application of NBC001 remarkably reduced the penetration of nematodes into the roots. Histochemical and fluorometric staining analyses indicate that application of NBC001 stimulated hydrogen peroxide activity in the roots and triggered callose deposition in the leaves and roots. Transcription of the PR1a and EREBP genes in the salicylic acid and ethylene signaling pathways was upregulated in soybean plants treated with NBC001. However, the application of concentrated culture filtrate of NBC001 had no significant impacts on the soil microbial community based on next generation DNA sequencing technology. In summary, NBC001 may be a good biocontrol agent against H. glycines via stimulation of the immunity/defense of the plant host.


Assuntos
Aspergillus niger/fisiologia , Agentes de Controle Biológico/farmacologia , Tylenchida/efeitos dos fármacos , Animais , Aspergillus niger/isolamento & purificação , Peróxido de Hidrogênio/metabolismo , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/parasitologia , Ácido Salicílico/metabolismo , Microbiologia do Solo , Glycine max/crescimento & desenvolvimento , Glycine max/metabolismo , Glycine max/parasitologia , Tylenchida/crescimento & desenvolvimento
20.
Appl Environ Microbiol ; 85(2)2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30413474

RESUMO

Proteins are secreted throughout the mycelium of Aspergillus niger except for the sporulating zone. A link between sporulation and repression of protein secretion was underlined by the finding that inactivation of the sporulation gene flbA results in mycelial colonies that secrete proteins throughout the colony. However, ΔflbA strain hyphae also lyse and have thinner cell walls. This pleiotropic phenotype is associated with differential expression of 36 predicted transcription factor genes, one of which, rpnR, was inactivated in this study. Sporulation, biomass, and secretome complexity were not affected in the ΔrpnR deletion strain of the fungus. In contrast, ribosomal subunit expression and protein secretion into the medium were reduced when A. niger was grown on xylose. Moreover, the ΔrpnR strain showed decreased resistance to H2O2 and the proteotoxic stress-inducing agent dithiothreitol. Taking the data together, RpnR is involved in proteotoxic stress resistance and impacts protein secretion when A. niger is grown on xylose.IMPORTANCEAspergillus niger secretes a large amount and diversity of industrially relevant enzymes into the culture medium. This makes the fungus a widely used industrial cell factory. For instance, carbohydrate-active enzymes of A. niger are used in biofuel production from lignocellulosic feedstock. These enzymes represent a major cost factor in this process. Higher production yields could substantially reduce these costs and therefore contribute to a more sustainable economy and less dependence on fossil fuels. Enzyme secretion is inhibited in A. niger by asexual reproduction. The sporulation protein FlbA is involved in this process by impacting the expression of 36 predicted transcription factor genes. Here, we show that one of these predicted transcriptional regulators, RpnR, regulates protein secretion and proteotoxic stress resistance. The gene is thus an interesting target to improve enzyme production in A. niger.


Assuntos
Aspergillus niger/fisiologia , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica/fisiologia , Estresse Fisiológico/genética , Xilose/metabolismo , Aspergillus niger/genética , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/metabolismo
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