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1.
Microbiol Spectr ; 12(2): e0340523, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38230929

RESUMO

The white rot fungus Cerrena unicolor 87613 has been previously shown to be a promising resource in laccase production, an enzyme with significant biotechnological applications. Conventional methods face technical challenges in improving laccase activity. Attempts are still being made to develop novel approaches for further enhancing laccase activity. This study aimed to understand the regulation of laccase activity in C. unicolor 87613 for a better exploration of the novel approach. Transcriptomic and metabolomic analyses were performed to identify key genes and metabolites involved in extracellular laccase activity. The findings indicated a strong correlation between the glutathione metabolism pathway and laccase activity. Subsequently, experimental verifications were conducted by manipulating the pathway using chemical approaches. The additive reduced glutathione (GSH) dose-dependently repressed laccase activity, while the GSH inhibitors (APR-246) and reactive oxygen species (ROS) inducer (H2O2) enhanced laccase activity. Changes in GSH levels could determine the intracellular redox homeostasis in interaction with ROS and partially affect the expression level of laccase genes in C. unicolor 87613 in turn. In addition, GSH synthetase was found to mediate GSH abundance in a feedback loop. This study suggests that laccase activity is negatively influenced by GSH metabolism and provides a theoretical basis for a novel strategy to enhance laccase activity by reprogramming glutathione metabolism at a specific cultivation stage.IMPORTANCEThe production of laccase activity is limited by various conventional approaches, such as heterologous expression, strain screening, and optimization of incubation conditions. There is an urgent need for a new strategy to meet industrial requirements more effectively. In this study, we conducted a comprehensive analysis of the transcriptome and metabolome of Cerrena unicolor 87613. For the first time, we discovered a negative role played by reduced glutathione (GSH) and its metabolic pathway in influencing extracellular laccase activity. Furthermore, we identified a feedback loop involving GSH, GSH synthetase gene, and GSH synthetase within this metabolic pathway. These deductions were confirmed through experimental investigations. These findings not only advanced our understanding of laccase activity regulation in its natural producer but also provide a theoretical foundation for a strategy to enhance laccase activity by reprogramming glutathione metabolism at a specific cultivation stage.


Assuntos
Cebus , Lacase , Polyporales , Transcriptoma , Lacase/genética , Lacase/metabolismo , Espécies Reativas de Oxigênio , Peróxido de Hidrogênio , Perfilação da Expressão Gênica , Glutationa , Ligases/genética , Ligases/metabolismo
2.
J Agric Food Chem ; 71(14): 5686-5699, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37012896

RESUMO

This study sought to understand how the features of proteins impact the properties of nanoparticles assembled using the pH-shifting approach and the mechanism behind. Four legume protein isolates from faba bean, mung bean, soy, and pea were fractionated into natural aqueous-soluble (Sup) and aqueous-insoluble (Sed) fractions, which were proved to serve as shell and core, respectively, for the pH-driven-assembled nanoparticles. Using zein instead of Sed fractions as the core improved size uniformity, and particle size can be precisely controlled by adjusting core/shell ratios. Using the proteomic technique and silico characterization, the features of identified proteins indicated that hydrophobicity rather than molecular weight, surface charge, etc., mainly determined particle size. With molecular docking, structural analysis, and dissociation tests, the assembly of zein/Sup-based nanoparticles was dominantly driven by hydrophobic interactions. This study provides constructive information on the correlation between protein features and the properties of pH-driven-assembled nanoparticles, achieving a precise control of particle size.


Assuntos
Nanopartículas , Zeína , Tamanho da Partícula , Zeína/química , Simulação de Acoplamento Molecular , Proteômica , Proteínas/química , Nanopartículas/química , Concentração de Íons de Hidrogênio
3.
Biochem Biophys Res Commun ; 653: 69-75, 2023 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-36857902

RESUMO

The medium-temperature alpha-amylase of Bacillus amyloliquefaciens is widely used in the food and washing process. Enhancing the thermostability of alpha-amylases and investigating the mechanism of stability are important for enzyme industry development. The optimal temperature and pH of the wild-type BAA and mutant MuBAA (D28E/V118A/S187D/K370 N) were all 60 °C and 6.0, respectively. The mutant MuBAA showed better thermostability at 50 °C and 60 °C, with a specific activity of 206.61 U/mg, which was 99.1% greater than that of the wild-type. By analyzing predicted structures, the improving thermostability of the mutant MuBAA was mainly related to enhanced stabilization of a loop region in domain B via more calcium-binding sites and intramolecular interactions around Asp187. Furthermore, additional intramolecular interactions around sites 28 and 370 in domain A were also beneficial for improving thermostability. Additionally, the decrease of steric hindrance at the active cavity increased the specific activity of the mutant MuBAA. Improving the thermostability of BAA has theoretical reference values for the modification of alpha-amylases.


Assuntos
Bacillus amyloliquefaciens , Bacillus , Bacillus amyloliquefaciens/genética , Bacillus amyloliquefaciens/metabolismo , Sequência de Aminoácidos , alfa-Amilases/genética , alfa-Amilases/química , alfa-Amilases/metabolismo , Estabilidade Enzimática , Temperatura , Mutação
4.
Fungal Biol ; 127(1-2): 872-880, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36746559

RESUMO

Phenolic compounds are widely distributed in nature and industrial environment, and their detoxification or bioactive enhancement is of great value to environmental protection and industrial development. Laccases are multicopper oxidases that catalyse the oligo- or polymerisation of phenolic compounds. Identifying new laccase producers and investigating their application potential are of great importance. In this study, a white-rot fungus, Trametes hirsuta EZ1, with significantly high laccase productivity was isolated. The optimum conditions were studied for the maximum fermentation of extracellular laccase, which was achieved at 150 U/mL with a medium containing 10% strain EZ1, 7% maltodextrin, 1.5% peptone, and 0.5 mM Cu2+, and incubation at initial pH 6.0, 32 °C, and 180 rpm for nine days. Subsequently, a 70-kDa laccase was purified that showed activity over a wide range of temperature and pH, sensitivity to many metal ions and sodium dodecyl sulphate, and high tolerance to organic solvents. Purified laccase showed a significant unreported effect by catalysing catechol or ferulic acid into dimers, trimers, and tetramers or caffeic acid into dimers, trimers, tetramers, and pentamers. The oligomeric mixtures exhibited increased antioxidative capacity compared to that of each parent monomer, except for caffeic acid derivatives. Our study offers a novel strain source for laccase production and broadens its application in the enhancement of bioactive compounds.


Assuntos
Polyporaceae , Trametes , Lacase
5.
Int J Mol Sci ; 23(6)2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35328337

RESUMO

This study aimed to improve the stability and catalytic properties of Thermomyces lanuginosus lipase (TLL) adsorbed on a hydrophobic support. At the optimized conditions (pH 5 and 25 °C without any additions), the Sips isotherm model effectively fitted the equilibrium adsorption data, indicating a monolayer and the homogenous distribution of immobilized lipase molecules. To preserve the high specific activity of adsorbed lipase, the immobilized lipase (IL) with a moderate loading amount (approximately 40% surface coverage) was selected. Polyethylenimine (PEI) and chitosan (CS) were successfully applied as bridging units to in situ crosslink the immobilized lipase molecules in IL. At the low polymer concentration (0.5%, w/w) and with 1 h incubation, insignificant changes in average pore size were detected. Short-chain PEI and CS (MW ≤ 2 kDa) efficiently improved the lipase stability, i.e., the lipase loss decreased from 40% to <2%. Notably, CS performed much better than PEI in maintaining lipase activity. IL crosslinked with CS-2 kDa showed a two- to three-fold higher rate when hydrolyzing p-nitrophenyl butyrate and a two-fold increase in the catalytic efficiency in the esterification of hexanoic acid with butanol. These in situ crosslinking strategies offer good potential for modulating the catalytic properties of TLL for a specific reaction.


Assuntos
Quitosana , Eurotiales , Enzimas Imobilizadas/química , Lipase/química , Polietilenoimina/química , Polímeros
6.
Ecotoxicol Environ Saf ; 234: 113412, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35304333

RESUMO

Laccase, a multicopper oxidase, is well known for its industrial potentials to remove environmental pollutants due to its low substrate specificity to oxidize phenols and thus catalytic versatility. Many efforts focused on the metabolic mechanism, yet to decipher the structural determinants responsible for the differentiation between substrates. Aflatoxin B1 (AFB1), a new substrate for laccase, is a mycotoxin with a formidable environmental threat to public health and food safety. In the present study, we combined biochemical, in silico mutational and molecular-docking data to gain an insight to the function of key residues in the active cavity close to the T1 copper site in a characterized recombinant laccase from Cerrena unicolor (rCuL). Kinetic data for computer-assisted virtual mutants established the binding affinity of hydrogen bonds and residues (Asn336, Asp207, Val391, and Thr165) in rCuL to AFB1. The augmented binding affinity to AFB1 may be related to the conformational rearrangements of the laccase and its ability to hydrogen-bond with the substrate. Furthermore, the optimal pH and temperature for rCuL and variants mediated AFB1 degradation may depend on their pH stability and thermostability. Our findings reinforce the importance of the structure-function relationship of fungal laccases in degrading AFB1, providing mechanistic guidance for future biocatalyst and bioengineering applications.

7.
Antibiotics (Basel) ; 11(2)2022 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-35203847

RESUMO

Microbial antibiotic resistance has become a worldwide concern, as it weakens the efficiency of the control of pathogenic microbes in both the fields of medicine and plant protection. A better understanding of antibiotic resistance mechanisms is helpful for the development of efficient approaches to settle this issue. In the present study, GC-MS-based metabolomic analysis was applied to explore the mechanisms of Zhongshengmycin (ZSM) resistance in Xanthomonas oryzae (Xoo), a bacterium that causes serious disease in rice. Our results show that the decline in the pyruvate cycle (the P cycle) was a feature for ZSM resistance in the metabolome of ZSM-resistant strain (Xoo-ZSM), which was further demonstrated as the expression level of genes involved in the P cycle and two enzyme activities were reduced. On the other hand, alanine was considered a crucial metabolite as it was significantly decreased in Xoo-ZSM. Exogenous alanine promoted the P cycle and enhanced the ZSM-mediated killing efficiency in Xoo-ZSM. Our study highlights that the depressed P cycle is a feature in Xoo-ZSM for the first time. Additionally, exogenous alanine is a candidate enhancer and can be applied with ZSM to improve the antibiotic-mediated killing efficiency in the control of infection caused by Xoo.

8.
J Invertebr Pathol ; 181: 107564, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33689762

RESUMO

Beauveria bassiana is a critical entomopathogenic fungus for pest biocontrol, whose efficiency depends on fungal development and stress resistance. Unlike its revealed location in plasma membrane patches in other organisms, B. bassiana Sur7 specifically localized in vacuoles. This vacuolar Sur7 was previously demonstrated to affect stress tolerance, hyphal development and virulence. There, however, remain more mechanistic details to be explored. In this study, transcriptomics and metabolomics were applied to investigate the mechanism of vacuolar Sur7. Analyses of transcriptomics and metabolomics displayed many differentially expressed genes and abundant metabolites in response to Sur7 loss, respectively. Together with genes associated with vacuolar biofunction (including transportation and hydrolysis), the altered metabolites contributed to cell wall construction and stress resistance. Particularly, an N-acetylglucosamine-associated Brg1/Nrg1 pathway was enriched and partially affected by Sur7. Absence of Sur7 changed the expression level of Brg1/Nrg1 pathway-related transcript factors, which interfered with downstream phenotype of sporulation. In addition, Sur7 was involved in the accumulation of sphingoid bases, which may affect sphingolipid-related signaling pathway. Although experimental evidence is further required, our studies provide a preliminary framework for future exploring the regulatory mechanism of Sur7, and give a new version of metabolic agency connecting Sur7 and downstream signaling pathway.


Assuntos
Beauveria/genética , Agentes de Controle Biológico , Proteínas Fúngicas/genética , Proteínas de Membrana/genética , Metaboloma , Transcriptoma , Beauveria/metabolismo , Agentes de Controle Biológico/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas de Membrana/metabolismo , Controle Biológico de Vetores
9.
FEMS Microbiol Lett ; 368(3)2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33512422

RESUMO

Integrity of the cell wall is requisite for fungal growth and function. Sur7 governs cell wall composition, and affects conidial sporulation and germination in Beauveria bassiana, a filamentous entomopathogenic fungus. The role of Sur7 in fungal growth on various nutrients remains unclear. We have previously reported that Sur7 deletion results in the attenuation of B. bassiana growth on supplemented Sabouraud dextrose agar (SDAY) and minimal Czapek-Dox agar (CDA) compared to wild type (WT). Here, we used transcriptomic analysis to compare WT and Sur7 mutant (ΔSur7) responses to CDA and SDAY. Growth on CDA, compared with that on SDAY, affected the expression of more genes in the WT than in the mutant. Differentially expressed genes were enriched for transportation process terms in the ΔSur7 mutant and metabolic process terms in the WT. Different processes were repressed in the ΔSur7 (metabolic process) and WT (ribosome synthesis) cells. Despite the shared enrichment of nitrogen metabolism genes, differentially expressed genes were enriched in distinct saccharide-energy metabolism terms in each strain. We conclude that Sur7 ensures the growth of B. bassiana in a minimal medium by influencing the expression of genes involved in the consumption of sucrose via specific energy metabolism pathways.


Assuntos
Beauveria/efeitos dos fármacos , Beauveria/genética , Proteínas Fúngicas/genética , Nutrientes/farmacologia , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Perfilação da Expressão Gênica
10.
Electrophoresis ; 42(24): 2599-2614, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33314167

RESUMO

The application of monolithic materials as carriers for enzymes has rapidly expanded to the realization of flow-through analysis and bioconversion processes. This expansion is partly attributed to the absence from diffusion limitation in many monoliths-based enzyme reactors. Particularly, the relatively ease of introducing functional groups renders polymer monoliths attractive as enzyme carriers. After summarizing the motivation to develop enzymatic reactors using polymer monoliths, this review reports the most recent applications of such reactors. Besides, the present review focuses on the crucial characteristics of polymer monoliths affecting the immobilization of enzymes and the processing parameters dictating the performance of the resulting enzymatic reactors. This review is intended to provide a guideline for designing and applying flow-through enzymatic reactors using polymer monoliths.


Assuntos
Reatores Biológicos , Enzimas Imobilizadas , Polímeros , Motivação
11.
Toxins (Basel) ; 12(8)2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32727016

RESUMO

Aflatoxin B1 (AFB1) is a known toxic human carcinogen and can be detoxified by laccases, which are multicopper oxidases that convert several environmental pollutants and toxins. In this study, a new laccase that could catalyze AFB1 degradation was purified and identified from the white-rot fungus Cerrena unicolor 6884. The laccase was purified using (NH4)2SO4 precipitation and anion exchange chromatography, and then identified as Lac 2 through zymogram and UHPLC-MS/MS based on the Illumina transcriptome analysis of C. unicolor 6884. Six putative laccase protein sequences were obtained via functional annotation. The lac 2 cDNA encoding a full-length protein of 512 amino acids was cloned and sequenced to expand the fungus laccase gene library for AFB1 detoxification. AFB1 degradation by Lac 2 was conducted in vitro at pH 7.0 and 45 °C for 24 h. The half-life of AFB1 degradation catalyzed by Lac 2 was 5.16 h. Acetosyringone (AS), Syrinagaldehyde (SA) and [2,2' -azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) at 1 mM concentration seemed to be similar mediators for strongly enhancing AFB1 degradation by Lac 2. The product of AFB1 degradation catalyzed by Lac 2 was traced and identified to be Aflatoxin Q1 (AFQ1) based on mass spectrometry data. These findings are promising for a possible application of Lac 2 as a new aflatoxin oxidase in degrading AFB1 present in food and feeds.


Assuntos
Aflatoxina B1/química , Lacase/química , Polyporales/enzimologia , Sequência de Aminoácidos , Contaminação de Alimentos/prevenção & controle , Lacase/genética , Lacase/isolamento & purificação , Filogenia , Polyporales/genética
13.
Appl Microbiol Biotechnol ; 104(11): 4675-4703, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32274562

RESUMO

This article reviews mushrooms with anti-breast cancer activity. The mushrooms covered which are better known include the following: button mushroom Agaricus bisporus, Brazilian mushroom Agaricus blazei, Amauroderma rugosum, stout camphor fungus Antrodia camphorata, Jew's ear (black) fungus or black wood ear fungus Auricularia auricula-judae, reishi mushroom or Lingzhi Ganoderma lucidum, Ganoderma sinense, maitake mushroom or sheep's head mushroom Grifola frondosa, lion's mane mushroom or monkey head mushroom Hericium erinaceum, brown beech mushroom Hypsizigus marmoreus, sulfur polypore mushroom Laetiporus sulphureus, Lentinula edodes (shiitake mushroom), Phellinus linteus (Japanese "meshimakobu," Chinese "song gen," Korean "sanghwang," American "black hoof mushroom"), abalone mushroom Pleurotus abalonus, king oyster mushroom Pleurotus eryngii, oyster mushroom Pleurotus ostreatus, tuckahoe or Fu Ling Poria cocos, and split gill mushroom Schizophyllum commune. Antineoplastic effectiveness in human clinical trials and mechanism of anticancer action have been reported for Antrodia camphorata, Cordyceps sinensis, Coriolus versicolor, Ganoderma lucidum, Grifola frondosa, and Lentinula edodes.


Assuntos
Agaricales/química , Agaricales/classificação , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Ensaios Clínicos como Assunto , Misturas Complexas/química , Misturas Complexas/farmacologia , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Ratos
14.
Arch Microbiol ; 202(5): 1005-1013, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31932863

RESUMO

Pectinase is widely used in numerous industrial fields, including the food, wine, and paper industries. In this work, seven bacteria were isolated from orange peel and their pectinase production activity was assayed. One bacterium (OR-B2) identified as a Bacillus sp. showed the highest enzyme activity towards others. A gene encoding a pectate lyase designed as PelB-B2 in this work was amplified and heterogeneous expressed in E.coli. PelB-B2 was defined as a member of the PelB pectate lyase family after phylogenic tree analysis. 3D model of PelB-B2 was constructed by SWISS-MODEL and PelB-B2 showed conserved para-ß structure. After inducing culture and purified by Ni-affinity chromatography, the properties of the purified PelB-B2 were assayed. Optimal pH and temperature for PelB-B2 was pH 8.0 and 50 °C, respectively. PelB-B2 showed excellent pH stability and thermostability. It was stable within pH range 3.0-11.0 and retained more than 51% activity after incubation at 40 °C, 50 °C, or 60 °C for 1 h. Furthermore, we determined that PelB-B2 was a Ca2+-dependent pectinase and the pectin extracted from citrus was the benefit substrate for PelB-B2. The Km and Vmax of PelB-B2 were 1.64 g/L and 232.56 mol/(L min), respectively. The OR-B2 can be a new resource for pectinase production and the PelB-B2 has potential for industrial application. 7 bacteria were isolated from orange peel, namely OR-B1 to OR-B7 and their pectinase activities were assayed. One pectate lyase belongs to PelB family was cloned from OR-B2 and heterogeneous expressed in E. coli. Purified PelB-B2 was further studied with its properties. Effects of pH, temperature, chemicals, substrate on the enzyme activity were assayed and the enzyme kinetic was also measured.


Assuntos
Bacillus/enzimologia , Pectinas/metabolismo , Poligalacturonase/metabolismo , Bacillus/genética , Bacillus/metabolismo , Citrus/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Poligalacturonase/biossíntese , Polissacarídeo-Liases/metabolismo , Temperatura
15.
Electron. j. biotechnol ; 42: 49-55, Nov. 2019. tab, ilus, graf
Artigo em Inglês | LILACS | ID: biblio-1087461

RESUMO

Background: Protein glutaminase specifically deamidates glutamine residue in protein and therefore significantly improves protein solubility and colloidal stability of protein solution. In order to improve its preparation efficiency, we exploited the possibility for its secretory expression mediated by twin-arginine translocation (Tat) pathway in Bacillus licheniformis. Results: The B. licheniformis genome-wide twin-arginine signal peptides were analyzed. Of which, eleven candidates were cloned for construction of expression vectors to mediate the expression of Chryseobacterium proteolyticum protein glutaminase (PGA). The signal peptide of GlmU was confirmed that it significantly mediated PGA secretion into media with the maximum activity of 0.16 U/ml in Bacillus subtilis WB600. A mutant GlmU-R, being replaced the third residue aspartic acid of GlmU twin-arginine signal peptide with arginine by site-directed mutagenesis, mediated the improved secretion of PGA with about 40% increased (0.23 U/ml). In B. licheniformis CBBD302, GlmU-R mediated PGA expression in active form with the maximum yield of 6.8 U/ml in a 25-l bioreactor. Conclusions: PGA can be produced and secreted efficiently in active form via Tat pathway of B. licheniformis, an alternative expression system for the industrial-scale production of PGA.


Assuntos
Bacillus licheniformis/enzimologia , Glutaminase/metabolismo , Arginina , Plasmídeos , Prostaglandinas A/química , Bacillus subtilis , Sinais Direcionadores de Proteínas , Sequência de Bases , Mutagênese Sítio-Dirigida , Ácido Aspártico , Escherichia coli , Bacillus licheniformis/genética , Glutaminase/genética
16.
Front Neurol ; 10: 421, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31114536

RESUMO

Background: Hyponatremia has frequently been described as a common complication associated with bacterial meningitis, though its frequency and clinical course in children with bacterial meningitis are unclear. The present study aimed to investigate the frequency, clinical characteristics, and prognosis associated with pediatric hyponatremia due to bacterial meningitis. Methods: We performed a retrospective review of children with bacterial meningitis provided with standard care. One hundred seventy-five children were included. We documented all participants' symptoms and signs, laboratory and microbiological data, radiological findings, and complications that occurred during their hospital admission. Disease severity was determined using the maximum Pediatric Cerebral Performance Category (PCPC) and minimum Glasgow Coma Scale (GCS). Residual deficits were assessed using PCPC at discharge. Results: Hyponatremia (<135 mmol/L) was seen in 116 (66.4%) of the patients assessed and was classified as mild (130-135 mmol/L) in 77, moderate (125-129 mmol/L) in 26, and severe (<125 mmol/L) in 13. Hyponatremia was associated with a shorter duration of symptoms before admission, higher CSF white cell counts, and a longer duration of hospitalization. Moderate and severe hyponatremia were associated with an increase in convulsions, impaired consciousness, altered CSF protein levels, higher maximum PCPC scores, and lower minimum GCS scores. Severe hyponatremia was further associated with the development of systemic complications including shock, multiple organ dysfunction syndrome, respiratory failure requiring mechanical ventilation, and an increase in poor outcome (PCPC ≥ 2). Hyponatremia was not associated with the development of neurologic complications. Logistic regression analyses revealed that convulsions (OR 12.09, 95% CI 2.63-56.84) and blood glucose levels > 6.1 mmol/L (OR 8.28, 95% CI 1.65-41.60) predicted severe hyponatremia. Conclusion: Hyponatremia occurred in 66.4% of the assessed pediatric bacterial meningitis patients. Moderate and severe hyponatremia affected the severity of pediatric bacterial meningitis. Only severe hyponatremia affected the short-term prognosis of patients with pediatric bacterial meningitis. We recommend that patients with pediatric bacterial meningitis who exhibit convulsions and increased blood glucose levels should be checked for severe hyponatremia. Further studies are needed to evaluate the effectiveness of treatment of hyponatremia.

17.
J Food Sci ; 84(6): 1456-1464, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31107551

RESUMO

A novel shortening was developed based on oleogels structured by ethylcellulose (EC) polymers. The texture and oil retention ability of EC oleogels were characterized against the level of viscosity of different grades of EC, as well as the rheological properties in relation to the polymer structure in the gel network. EC100, which has an average viscosity of 100 cP, was selected as the most suitable organogelator at 4% (w/w) in combination with base oil (30% degree of saturation by mixing palm stearin and soybean oil) to form the shortening. Triglyceryl monostearate (TMS) was found to be the most effective emulsifier as evidenced by its ability to strengthen air-incorporation ability of the shortening while creating evenly distributed fine crystals in the system. The EC100 shortening was able to create breads with excellent specific volume, indicating its ability to incorporate air bubbles during dough development and to serve as an antifirming agent to create bread with stable soft texture. PRACTICAL APPLICATION: In the present study, we attempted to create a novel shortening by employing oleogels structured by ethylcellulose (EC), the most promising gelation agent to develop gel network capable of replacing solid fat without health concerns. EC oleogels in shortening with detailed characterization of the shortening microstructure in relation to its functional properties was elucidated. The optimal formulation in relation to preservation of gel structure and consistency with enhanced moisture and air retention were also identified.


Assuntos
Celulose/análogos & derivados , Gorduras na Dieta/análise , Pão/análise , Celulose/química , Culinária/métodos , Emulsificantes , Géis/química , Glicerídeos/química , Compostos Orgânicos/química , Óleo de Palmeira/química , Polímeros/química , Reologia , Óleo de Soja/química , Viscosidade
18.
J Microbiol Biotechnol ; 29(5): 765-775, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-30982319

RESUMO

A new α-amylase-encoding gene (amySL3) of glycoside hydrolase (GH) family 13 was identified in soda lake isolate Alkalibacterium sp. SL3. The deduced AmySL3 shares high identities (82-98%) with putative α-amylases from the genus Alkalibacterium, but has low identities (<53%) with functionally characterized counterparts. amySL3 was successfully expressed in Escherichia coli, and the recombinant enzyme (rAmySL3) was purified to electrophoretic homogeneity. The optimal temperature and pH of the activity of the purified rAmySL3 were determined to be 45°C and pH 7.5, respectively. rAmySL3 was found to be extremely halophilic, showing maximal enzyme activity at a nearly saturated concentration of NaCl. Its thermostability was greatly enhanced in the presence of 4 M NaCl, and it was highly stable in 5 M NaCl. Moreover, the enzyme did not require calcium ions for activity, and was strongly resistant to a range of surfactants and hydrophobic organic solvents. The major hydrolysis products of rAmySL3 from soluble starch were maltobiose and maltotriose. The high ratio of acidic amino acids and highly negative electrostatic potential surface might account for the halophilic nature of AmySL3. The extremely halophilic, calcium-independent, and surfactant-resistant properties make AmySL3 a promising candidate enzyme for both basic research and industrial applications.


Assuntos
Cálcio/efeitos adversos , Carnobacteriaceae/enzimologia , Halobacteriales , Tensoativos/efeitos adversos , alfa-Amilases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carnobacteriaceae/genética , Clonagem Molecular , DNA Bacteriano , Ensaios Enzimáticos , Estabilidade Enzimática , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Concentração de Íons de Hidrogênio , Lagos/microbiologia , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Alinhamento de Sequência , Análise de Sequência de Proteína , Cloreto de Sódio , Solventes/efeitos adversos , Amido/metabolismo , Especificidade por Substrato , Temperatura , alfa-Amilases/efeitos dos fármacos , alfa-Amilases/genética
19.
Biotechnol Lett ; 41(3): 409-418, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30644013

RESUMO

OBJECTIVE: To explore the diversity of glycoside hydrolase family 10 xylanase genes in the sediment of soda lake Dabusu by using high-throughput amplicon sequencing based on the Illumina HiSeq2500 platform. RESULTS: A total of 227,420 clean reads, representing approximately 49.5 M bp, were obtained. Operational taxonomic unit (OTU) classification, with a 95% sequence identity cut-off, resulted in 467 OTUs with 392 annotated as GH10 xylanase, exhibiting 35-99% protein sequence identity with their closest-related xylanases in GenBank. Above 75% of the total OTUs demonstrated less than 80% identity with known xylanases. In addition, xylanases derived from the sediment were found to be affiliated to 12 different phyla, with Bacteroidetes, Proteobacteria, Actinobacteria, Firmicutes, Verrucomicrobia, and Basidiomycota being the dominant phyla. Moreover, barcode sequence had a major effect on abundance with only a minor effect on diversity. CONCLUSIONS: High-throughput amplicon sequencing offers insight into xylanase gene diversity at a substantially higher resolution and lesser cost than library cloning and Sanger sequencing, facilitating a more thorough understanding of xylanase distribution and ecology.


Assuntos
Variação Genética , Sedimentos Geológicos/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala , Lagos/microbiologia , Metagenômica , Xilosidases/genética , Bactérias/enzimologia , China , Análise por Conglomerados , Fungos/enzimologia , Filogenia , Homologia de Sequência
20.
Curr Protein Pept Sci ; 20(3): 265-276, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29895244

RESUMO

A variety of fungi, plants, and their different tissues are used in Traditional Chinese Medicine to improve health, and some of them are recommended for dietary therapy. Many of these plants and fungi contain antifungal proteins and peptides which suppress spore germination and hyphal growth in phytopathogenic fungi. The aim of this article is to review antifungal proteins produced by medicinal plants and fungi used in Chinese medicine which also possess anticancer and human immunodeficiency virus-1 (HIV-1) enzyme inhibitory activities.


Assuntos
Fármacos Anti-HIV/farmacologia , Antifúngicos , Antineoplásicos , Proteínas Fúngicas , Proteínas de Plantas , Plantas Medicinais/química , Animais , Fármacos Anti-HIV/química , Antifúngicos/química , Antifúngicos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Proteínas Fúngicas/química , Proteínas Fúngicas/farmacologia , Humanos , Medicina Tradicional Chinesa , Proteínas de Plantas/química , Proteínas de Plantas/farmacologia
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