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1.
Skeletal Radiol ; 48(1): 163-165, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29876592

RESUMO

The transverse acetabular ligament is an unusual location for ganglion cysts. Only a few cases have been reported in the literature. They can be asymptomatic and represent an incidental finding or can cause an atypical pattern of hip joint/groin pain. We report a case of ganglion cyst arising from the TAL causing entrapment of the anterior branch of the obturator nerve with associated acute denervation of the abductor longus (AL), adductor brevis (AB), and gracilis muscles.


Assuntos
Cistos Glanglionares/complicações , Cistos Glanglionares/diagnóstico por imagem , Síndromes de Compressão Nervosa/diagnóstico por imagem , Síndromes de Compressão Nervosa/etiologia , Nervo Obturador/lesões , Adulto , Cistos Glanglionares/cirurgia , Humanos , Ligamentos Articulares , Masculino , Síndromes de Compressão Nervosa/cirurgia , Radiografia Intervencionista , Sucção , Tomografia Computadorizada por Raios X
2.
Int J Health Care Qual Assur ; 31(1): 76-91, 2018 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-29504841

RESUMO

Purpose The purpose of this paper is to appraise Pai and Chary's (2016) conceptual framework for measuring patient-perceived hospital service quality (HSQ). Design/methodology/approach A structured questionnaire was used to obtain data from teaching, public and corporate hospital patients. Several tests were conducted to assess the instrument's reliability and validity. Pai and Chary's (2016) nine dimensions for measuring HSQ were examined in this paper. Findings The tests confirm that Pai and Chary's (2016) conceptual framework is reliable and valid. The study also establishes that the nine dimensions measure HSQ. Practical implications The framework empowers managers to assess service quality in any hospital settings, corporate, public and teaching, using an approach that is superior to the existing HSQ scales. Originality/value This paper helps researchers and practitioners to assess HSQ from patient perspectives in any hospital setting.


Assuntos
Hospitais/normas , Satisfação do Paciente , Percepção , Qualidade da Assistência à Saúde/normas , Inquéritos e Questionários/normas , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores Sexuais , Fatores Socioeconômicos , Adulto Jovem
3.
Appl Microbiol Biotechnol ; 101(6): 2357-2369, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27924363

RESUMO

The 3'-deleted amylopullulanase gene from the extreme thermophile Geobacillus thermoleovorans (Gt-apuΔC) was expressed extracellularly in Pichia pastoris under both methanol-inducible AOX1 and constitutive GAP promoters. The expression of the gene (Gt-apuΔC) was higher under GAP promoter (36.2 U ml-1, α-amylase; 33.5 U ml-1, pullulanase) than that under AOX1 promoter (32.5 and 28.6 U ml-1). The heavily glycosylated Gt-apuΔC from the recombinant P. pastoris displays higher substrate specificity, thermal stability and starch saccharification efficiency than that expressed in Escherichia coli. The enzyme hydrolyses maltotriose and maltotetraose unlike that expressed in E. coli. The enzyme action on wheat bran liberates maltose and glucose without detectable amount(s) of maltooligosaccharides. The sugars released from wheat bran (glucose and maltose) could be fractionated by ultrafiltration, as confirmed by TLC and HPLC analysis. This is the first report on the production of recombinant amylopullulanase extracellularly in P. pastoris.


Assuntos
Proteínas de Bactérias/química , Geobacillus/química , Glucose/química , Glicosídeo Hidrolases/química , Maltose/química , Pichia/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fibras na Dieta/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Geobacillus/enzimologia , Glucose/metabolismo , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Glicosilação , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Maltose/metabolismo , Pichia/genética , Regiões Promotoras Genéticas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade da Espécie , Especificidade por Substrato
4.
Bioprocess Biosyst Eng ; 40(5): 651-662, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28039507

RESUMO

The recombinant alkalistable and moderately thermostable bifunctional endoglucanase gene (BhCell-Xyl) of polyextremophilic bacterium Bacillus halodurans TSLV1 has been expressed in Pichia pastoris under constitutive GAP as well as inducible AOX promoters. A higher titre of recombinant BhCell-Xyl was attained after induction (4.8 U mL-1) as compared to that of the constitutive production (2.1 U mL-1). The recombinant P. pastoris strains integrated two copies of BhCell-Xyl under AOX and GAP promoters. The pure recombinant BhCell-Xyl is a glycoprotein of 66 kDa, which is optimally active at 60 °C and pH 6.0 and 8.0. Glycosylated BhCell-Xyl exhibits higher thermostability than that of the native enzyme. The analysis of amino acids of BhCell-Xyl revealed that multiple factors are responsible for its thermostability. Kinetics and in silico analysis of the enzyme suggested that BhCell-Xyl has one active site for both endocellulase and endoxylanase activities. The BhCell-Xyl possesses a carbohydrate binding domain and saccharifies lignocellulosic agro-residues to xylo-oligosaccharides and cello-oligosaccharides, suggesting its potential application in generating fermentable sugars from renewable agro-residues for biofuel and fine chemical industries.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Celulase/química , Glucuronatos/química , Lignina/química , Oligossacarídeos/química , Bacillus/genética , Proteínas de Bactérias/genética , Celulase/genética , Estabilidade Enzimática , Temperatura Alta , Concentração de Íons de Hidrogênio , Proteínas Recombinantes/química , Proteínas Recombinantes/genética
5.
Extremophiles ; 20(6): 831-842, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27558695

RESUMO

The thermostable bifunctional CMCase and xylanase encoding gene (rBhcell-xyl) from Bacillus halodurans TSLV1 has been expressed in Escherichia coli. The recombinant E. coli produced rBhcell-xyl (CMCase 2272 and 910 U L-1 xylanase). The rBhcell-xyl is a ~62-kDa monomeric protein with temperature and pH optima of 60 °C and 6.0 with T1/2 of 7.0 and 3.5 h at 80 °C for CMCase and xylanase, respectively. The apparent K m values (CMC and Birchwood xylan) are 3.8 and 3.2 mg mL-1. The catalytic efficiency (k cat/K m ) values of xylanase and CMCase are 657 and 171 mL mg-1 min-1, respectively. End-product analysis confirmed that rBhcell-xyl is a unique endo-acting enzyme with exoglucanase activity. The rBhcell-xyl is a GH5 family enzyme possessing single catalytic module and carbohydrate binding module. The action of rBhcell-xyl on corn cobs and wheat bran liberated reducing sugars, which can be fermented to bioethanol and fine biochemicals.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/genética , Celulases/genética , Microbiologia Industrial , Xilosidases/genética , Bacillus/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Celulases/química , Celulases/metabolismo , Produtos Agrícolas , Escherichia coli/genética , Escherichia coli/metabolismo , Fermentação , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Xilosidases/química , Xilosidases/metabolismo
6.
Appl Microbiol Biotechnol ; 100(13): 5661-79, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27142298

RESUMO

Pullulan hydrolyzing enzymes are endoacting, classified based on the substrate specificity and hydrolysis products as pullulanases (type I and II) and pullulan hydrolases (type I, II and III). Pullulanases and pullulan hydrolase type I are produced by bacteria and archaea. Among bacteria, many mesophilic, thermophilic and hyperthermophilic bacteria produce pullulanases and neopullulanases. While pullulan hydrolase type II and type III are produced by fungi and archaea, respectively. These are multi-domain proteins with three conserved catalytic acidic residues of the glycosyl hydrolases. The recent advances in molecular biology and protein engineering via mutagenesis and truncation led to improvement in thermostability, catalytic activity and substrate specificity. Pullulanases are debranching enzymes, which are widely employed in starch saccharification that minimizes the use of glucoamylase (approx. 50 %) and reduces the total reaction time of the industrial starch conversion process. The thermostable amylopullulanases are useful in one-step starch liquefaction and saccharification, which replaces amylolytic enzymes like α-amylase and glucoamylase, thus resulting in the reduction in the cost of sugar production. The enzymes also find application in making resistant starches and as an antistale in bread making. Panose and isopanose containing syrups are useful as prebiotics, while panose has also been reported to display anticarcinogenic activity. This review focuses on the distinguishing features of these enzymes based on the analysis of amino acid sequences and domain structure, besides highlighting recent advances in the molecular biology and protein engineering for enhancing their thermostability, catalytic activity and substrate specificity. This review also briefly summarizes the potential applications of pullulanases and pullulan hydrolases.


Assuntos
Archaea/enzimologia , Bactérias/enzimologia , Glucanos/metabolismo , Glicosídeo Hidrolases/química , Hidrolases/química , Engenharia de Proteínas , Archaea/química , Archaea/genética , Bactérias/química , Bactérias/genética , Biocatálise , Estabilidade Enzimática , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Hidrolases/genética , Hidrolases/metabolismo , Especificidade por Substrato
7.
J Ind Microbiol Biotechnol ; 43(4): 473-84, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26790418

RESUMO

The α-amylase (Ba-amy) of Bacillus acidicola was fused with DNA fragments encoding partial N- and C-terminal region of thermostable α-amylase gene of Geobacillus thermoleovorans (Gt-amy). The chimeric enzyme (Ba-Gt-amy) expressed in Escherichia coli displays marked increase in catalytic efficiency [K cat: 4 × 10(4) s(-1) and K cat/K m: 5 × 10(4) mL(-1) mg(-1) s(-1)] and higher thermostability than Ba-amy. The melting temperature (T m) of Ba-Gt-amy (73.8 °C) is also higher than Ba-amy (62 °C), and the CD spectrum analysis revealed the stability of the former, despite minor alteration in secondary structure. Langmuir-Hinshelwood kinetic analysis suggests that the adsorption of Ba-Gt-amy onto raw starch is more favourable than Ba-amy. Ba-Gt-amy is thus a suitable biocatalyst for raw starch saccharification at sub-gelatinization temperatures because of its acid stability, thermostability and Ca(2+) independence, and better than the other known bacterial acidic α-amylases.


Assuntos
Bacillus/enzimologia , Biocatálise , Escherichia coli/genética , Geobacillus/enzimologia , Proteínas Mutantes Quiméricas/genética , alfa-Amilases/química , alfa-Amilases/metabolismo , Bacillus/genética , Estabilidade Enzimática/genética , Escherichia coli/metabolismo , Geobacillus/genética , Concentração de Íons de Hidrogênio , Cinética , Proteínas Mutantes Quiméricas/química , Proteínas Mutantes Quiméricas/metabolismo , Estrutura Secundária de Proteína/genética , Amido/metabolismo , Temperatura , alfa-Amilases/genética
8.
Bioprocess Biosyst Eng ; 39(10): 1515-25, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27215773

RESUMO

Carbonic anhydrase (CA) was produced from the polyextremophilic (halotolerant, moderately thermophilic and alkaliphilic) bacterium Aeribacillus pallidus TSHB1 isolated from water and sediment samples of Choti Anhoni hot spring of Pipariya, Madhya Pradesh (India), is being reported to be suitable for carbon sequestration. Growth and CA production were inhibited at higher CO2 concentration (5-10 %). Under optimized culture variables (tryptone 0.8 %, yeast extract 0.08 %, glucose 1 %, micronutrient solution 1 %, inoculums size 1.10 %, agitation 200 at pH 8, and temperature 55 °C), 3.7-fold higher CA production was attained than that under unoptimized conditions. The zymogram analysis of the partially purified CA revealed an activity band corresponding to 32 kDa. The enzyme is stable in the pH range between 8.0 and 11.0 with T 1/2 of 40, 15, and 8 min at 60, 70, and 80 °C, respectively. The CA of A. pallidus displayed a marked enhancement in the rate of CaCO3 precipitation from aqueous CO2. The CA-aided formation of CaCO3 was 42.5 mg mg(-1) protein. Scanning electron microscopy revealed the formation of rhomboid calcite crystals. This is the first report on the production and applicability of CA from the polyextremophilic A. pallidus in carbon sequestration.


Assuntos
Bacillaceae/enzimologia , Proteínas de Bactérias/química , Materiais Biomiméticos/química , Anidrases Carbônicas/química , Estabilidade Enzimática
9.
Int J Health Care Qual Assur ; 29(3): 300-23, 2016 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-27120508

RESUMO

Purpose - Although measuring healthcare service quality is not a new phenomenon, the instruments used to measure are timeworn. With the shift in focus to patient centric processes in hospitals and recognizing healthcare to be different compared to other services, service quality measurement needs to be tuned specifically to healthcare. The purpose of this paper is to design a conceptual framework for measuring patient perceived hospital service quality (HSQ), based on existing service quality literature. Design/methodology/approach - Using HSQ theories, expanding existing healthcare service models and literature, a conceptual framework is proposed to measure HSQ. The paper outlines patient perceived service quality dimensions. Findings - An instrument for measuring HSQ dimensions is developed and compared with other service quality measuring instruments. The latest dimensions are in line with previous studies, but a relationship dimension is added. Practical implications - The framework empowers managers to assess healthcare quality in corporate, public and teaching hospitals. Originality/value - The paper helps academics and practitioners to assess HSQ from a patient perspective.


Assuntos
Administração Hospitalar/normas , Satisfação do Paciente , Indicadores de Qualidade em Assistência à Saúde/organização & administração , Inquéritos e Questionários/normas , Comunicação , Meio Ambiente , Pessoal de Saúde/normas , Humanos , Avaliação de Processos e Resultados em Cuidados de Saúde , Percepção , Relações Profissional-Paciente , Qualidade da Assistência à Saúde , Confiança
10.
Appl Microbiol Biotechnol ; 99(13): 5461-74, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25573470

RESUMO

In order to understand the role of N1 domain (1-257 aa) in the amylopullulanase (gt-apu) of the extremely thermophilic bacterium Geobacillus thermoleovorans NP33, N1 deletion construct (gt-apuΔN) has been generated and expressed in Escherichia coli. The truncated amylopullulanase (gt-apuΔN) exhibits similar pH and temperature optima like gt-apu, but enhanced thermostability. The gt-apuΔN has greater hydrolytic action and specific activity on pullulan than gt-apu. The k cat (starch and pullulan) and K m (starch) values of gt-apuΔN increased, while K m (pullulan) decreased. The enzyme upon N1 deletion hydrolyzed maltotetraose as the smallest substrate in contrast to maltopentaose of gt-apu. The role of N1 domain of gt-apu in raw starch binding has been confirmed, for the first time, based on deletion and Langmuir-Hinshelwood kinetics. Furthermore, N1 domain appears to exert a negative influence on the thermostability of gt-apu because N1 truncation significantly improves thermostability.


Assuntos
Geobacillus/enzimologia , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Amido/metabolismo , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Geobacillus/genética , Glucanos/metabolismo , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Cinética , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Estrutura Terciária de Proteína , Deleção de Sequência , Especificidade por Substrato , Temperatura
11.
J Ind Microbiol Biotechnol ; 42(10): 1389-400, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26264930

RESUMO

The phytase of the yeast Pichia anomala (PPHY) is a suitable biocatalyst as a food and feed additive because of its adequate thermostability, acid stability, protease insensitivity and broad substrate spectrum. The cell-bound nature and low phytase titres are the main bottlenecks for its utility in food and feed industries. In this investigation, we have overcome the problems by constitutive secretory expression of PPHY under glyceraldehyde phosphate dehydrogenase (GAP) promoter. A ~44-fold increase in rPPHY titre has been achieved after optimization of cultural variables by one-variable-at-a-time approach and two factorial statistical design. The use of GAP promoter makes the cultivation of the recombinant P. pastoris straight forward and eliminates the requirement of methanol for induction and hazards associated with its storage. Among metal-phytate complexes, Ca(2+) phytate is hydrolyzed more efficiently by rPPHY than Co(2+), Mn(2+), Mg(2+), Fe(3+) and Zn(2+) phytates. The enzyme is effective in dephytinizing whole wheat unleavened flat Indian breads (naan and tandoori) and different broiler feeds, thus mitigating anti-nutritional effects of phytates.


Assuntos
6-Fitase/biossíntese , Ração Animal/análise , Pão/análise , Galinhas , Ácido Fítico/metabolismo , Pichia/enzimologia , Triticum/química , 6-Fitase/genética , 6-Fitase/metabolismo , Animais , Estabilidade Enzimática , Aditivos Alimentares/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/genética , Hidrólise , Ácido Fítico/química , Pichia/genética , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Triticum/metabolismo
12.
J Anim Physiol Anim Nutr (Berl) ; 99(4): 646-60, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25132310

RESUMO

Fungal phytases are histidine acid phosphatases, a subclass of acid phosphatases, which catalyse the hydrolysis of phytic acid resulting in the release of phosphate moieties and thus mitigate its antinutritional properties. The supplementation of feed with phytases increases the bioavailability of phosphorus and minerals in non-ruminant animals and reduces the phosphorus pollution due to phosphorus excretion in the areas of intensive livestock production. Although phytases are reported in plants, animals and micro-organisms, fungal sources are used extensively for the production of phytases on a commercial scale. Phytases have been produced by fungi in both solid-state fermentation (SSF) and submerged fermentation (SmF). The fungal phytases are high molecular weight proteins ranging from 35 to 500 kDa. They are optimally active within pH and temperature ranges between 4.5 and 6.0, and 45 and 70 °C respectively. Phytate degradation leads to amelioration in the nutritional status of foods and feeds by improving the availability of minerals, phosphorus and proteins in non-ruminant animals and human beings and thus mitigates the environmental phosphorus pollution. Our article focuses on the role of fungal phytases in improving nutritional value of foods and feeds with concomitant increase in growth of non-ruminant animals and mitigating environmental phosphorus pollution.


Assuntos
6-Fitase/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Fungos/enzimologia , Animais , Gado , Ácido Fítico/metabolismo
13.
Indian J Exp Biol ; 53(3): 131-42, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25872243

RESUMO

Oligosaccharides and dietary fibres are non-digestible food ingredients that preferentially stimulate the growth of prebiotic Bifidobacterium and other lactic acid bacteria in the gastro-intestinal tract. Xylooligosaccharides (XOS) provide a plethora of health benefits and can be incorporated into several functional foods. In the recent times, there has been an over emphasis on the microbial conversion of agroresidues into various value added products. Xylan, the major hemicellulosic component of lignocellulosic materials (LCMs), represents an important structural component of plant biomass in agricultural residues and could be a potent bioresource for XOS. On an industrial scale, XOS can be produced by chemical, enzymatic or chemo-enzymatic hydrolysis of LCMs. Chemical methods generate XOS with a broad degree of polymerization (DP), while enzymatic processes will be beneficial for the manufacture of food grade and pharmaceutically important XOS. Xylooligomers exert several health benefits, and therefore, have been considered to provide relief from several ailments. This review provides a brief on production, purification and structural characterization of XOS and their health benefits.


Assuntos
Produtos Agrícolas/química , Glucuronatos , Oligossacarídeos , Prebióticos , Resíduos/análise , Adjuvantes Imunológicos/economia , Adjuvantes Imunológicos/isolamento & purificação , Adjuvantes Imunológicos/farmacologia , Adjuvantes Imunológicos/uso terapêutico , Animais , Anticarcinógenos/economia , Anticarcinógenos/isolamento & purificação , Anticarcinógenos/farmacologia , Anticarcinógenos/uso terapêutico , Antioxidantes/economia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Biomassa , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia/métodos , Produtos Agrícolas/economia , Fibras na Dieta/análise , Proteínas Fúngicas/metabolismo , Trato Gastrointestinal/microbiologia , Glucuronatos/economia , Glucuronatos/isolamento & purificação , Glucuronatos/farmacologia , Glucuronatos/uso terapêutico , Glicosídeo Hidrolases , Humanos , Hidrólise , Lignina/análise , Microbiota/efeitos dos fármacos , Dados de Sequência Molecular , Estrutura Molecular , Oligossacarídeos/economia , Oligossacarídeos/isolamento & purificação , Oligossacarídeos/farmacologia , Oligossacarídeos/uso terapêutico , Prebióticos/economia , Ultrafiltração , Resíduos/economia , Xilanos/química
14.
Appl Microbiol Biotechnol ; 98(10): 4503-19, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24413972

RESUMO

The gene (1,542 bp) encoding thermostable Ca(2+)-independent and raw starch hydrolyzing α-amylase of the extremely thermophilic bacterium Geobacillus thermoleovorans encodes for a protein of 50 kDa (Gt-amyII) with 488 amino acids. The enzyme is optimally active at pH 7.0 and 60 °C with a t 1/2 of 19.4 h at 60 and 4 h at 70 °C. Gt-amyII hydrolyses corn and tapioca raw starches efficiently and therefore finds application in starch saccharification at industrial sub-gelatinisation temperatures. The starch hydrolysis is facilitated following adsorption of the enzyme to starch at the C-terminal domain, as confirmed by the truncation analysis. The adsorption rate constant of Gt-amyII to raw corn starch is 37.6-fold greater than that for the C-terminus truncated enzyme (Gt-amyII-T). Langmuir-Hinshelwood kinetic analysis in terms of equilibrium parameter (K R) suggested that the adsorption of Gt-amyII to corn starch is more favourable than that of Gt-amyII-T. Thermodynamics of temperature inactivation indicated a decrease in thermostabilisation of Gt-amyII upon truncation of its C-terminus. The addition of raw corn starch increased t 1/2 of Gt-amyII, but it has no such effect on Gt-amyII-T. It can, therefore, be stated that Gt-amyII binds to raw corn starch via C-terminal region that contributes to its thermostability. Phylogenetic analysis confirmed that starch binding region of Gt-amyII is, in fact, the non-catalytic domain C, and not the typical SBD of CBM families. The role of domain C in raw starch binding throws light on the evolutionary path of the known SBDs.


Assuntos
Geobacillus/enzimologia , Amido/metabolismo , alfa-Amilases/metabolismo , Adsorção , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Cinética , Manihot/química , Peso Molecular , Filogenia , Ligação Proteica , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Amido/isolamento & purificação , Temperatura , Termodinâmica , Zea mays/química , alfa-Amilases/química
15.
J Ind Microbiol Biotechnol ; 41(6): 977-87, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24668018

RESUMO

The phytase (PPHY) of Pichia anomala has the requisite properties of thermostability and acidstability, broad substrate spectrum, and protease insensitivity, which make it a suitable candidate as a feed and food additive. The 1,389-bp PPHY gene was amplified from P. anomala genomic DNA, cloned in pPICZαA, and expressed extracellularly in P. pastoris X33. Three copies of PPHY have been detected integrated into the chromosomal DNA of the recombinant P. pastoris. The size exclusion chromatography followed by electrophoresis of the pure rPPHY confirmed that this is a homohexameric glycoprotein of ~420 kDa with a 24.3 % portion as N-linked glycans. The temperature and pH optima of rPPHY are 60 °C and 4.0, similar to the endogenous enzyme. The kinetic characteristics K(m), V(max), K(cat), and K(cat)/K(m) of rPPHY are 0.2 ± 0.03 mM, 78.2 ± 1.43 nmol mg(-1) s(-1), 65,655 ± 10.92 s(-1), and 328.3 ± 3.12 µM(-1) s(-1), respectively. The optimization of medium components led to a 21.8-fold improvement in rPPHY production over the endogenous yeast. The rPPHY titer attained in shake flasks could also be sustained in the laboratory fermenter. The rPPHY accounts for 57.1 % of the total secreted protein into the medium. The enzyme has been found useful in fractionating allergenic protein glycinin from soya protein besides dephytinization.


Assuntos
6-Fitase/biossíntese , Alérgenos/isolamento & purificação , Globulinas/isolamento & purificação , Pichia/enzimologia , Pichia/genética , Proteínas de Soja/isolamento & purificação , 6-Fitase/genética , 6-Fitase/metabolismo , Fracionamento Químico , Globulinas/imunologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas de Soja/imunologia , Temperatura
16.
Bioprocess Biosyst Eng ; 37(6): 1043-53, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24297158

RESUMO

A high titre of thermo-alkali-stable xylanase was attained in cane molasses medium. When the culture variables for endoxylanase production were optimized [cane molasses 7 %, soluble alkaline extract of wheat bran (SAE-WB) 37 % and ammonium chloride 0.30 %], a 4.5-fold enhancement in xylanase production (69 U ml(-1)) was achieved as compared to that in the unoptimized medium (15 U ml(-1)). The enzyme titre attained in shake flasks could be sustained in a 7-l laboratory bioreactor. An activity band corresponding to 40 kDa was visualized on SDS-PAGE zymogram analysis. The enzyme has broad range of pH and temperature for activity with optima at 9.0 and 80 °C, and stable between pH 4.0 and 11.0 with 85 % retention of activity. It has T 1/2 of 40 and 15 min at 70 and 80 °C. The enzyme is halotolerant since it displays activity in the presence of salt up to 15 %, and remains 100 % active in the absence of salt. The supplementation of whole wheat dough with xylanase improves antistaling property, reducing sugar content, bread volume with prebiotic xylooligosaccharides in bread. This is the first report on xylanase production in cane molasses medium with SAE-WB as the inducer and its applicability in whole wheat bread making that improves human health.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias , Pão , Endo-1,4-beta-Xilanases , Melaço , Saccharum/química , Triticum , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Endo-1,4-beta-Xilanases/biossíntese , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/isolamento & purificação , Estabilidade Enzimática , Humanos
17.
Extremophiles ; 17(5): 797-808, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23877303

RESUMO

The purified extracellular xylanase of polyextremophilic Bacillus halodurans TSEV1 has been visualized as a single band on SDS-PAGE and eluted as single peak by gel filtration, with a molecular mass of 40 kDa. The peptide finger print and cloned xylanase gene sequence analyses indicate that this enzyme belongs to GH family 10. The active site carboxyl residues are mainly involved in catalysis, while tryptophan residues are involved in substrate binding. The enzyme is optimally active at 80 °C and pH 9.0, and stable in the pH range of 7.0-12.0 with T 1/2 of 35 min at 80 °C (pH 9.0). Activation energy for birch wood xylan hydrolysis is 30.51 kJ mol(-1). The K m, V max and k cat (birchwood xylan) are 2.05 mg ml(-1), 333.33 µmol mg(-1 )min(-1) and 3.33 × 10(4) min(-1), respectively. The pKa1 and pKa2 of ionizable groups of the active site that influence V max are 8.51 and 11.0. The analysis of thermodynamic parameters for xylan hydrolysis suggests this as a spontaneous process. The enzyme is resistant to chemical denaturants like urea and guanidinium-HCl. The site-directed mutagenesis of catalytic glutamic acid residues (E196 and E301) resulted in a complete loss of activity. The birch wood xylan hydrolyzate contained xylobiose and xylotriose as the main products without any trace of xylose, and the enzyme hydrolyzes xylotetraose and xylopentaose rapidly to xylobiose. Thermo-alkali-stability, resistance to various chemical denaturants and mode of action make it a useful biocatalyst for generating xylo-oligosaccharides from agro-residues and bleaching of pulp in paper industries.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Termodinâmica , Xilosidases/química , Proteínas de Bactérias/genética , Domínio Catalítico , Estabilidade Enzimática , Temperatura Alta , Concentração de Íons de Hidrogênio , Hidrólise , Mutagênese Sítio-Dirigida , Ligação Proteica , Especificidade por Substrato , Madeira/química , Xilanos/química , Xilosidases/genética
18.
Extremophiles ; 17(3): 357-66, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23504033

RESUMO

An extremely thermophilic bacterial isolate that produces a high titer of thermostable endoxylanase and ß-xylosidase extracellularly in an inducible manner was identified as Geobacillus thermodenitrificans TSAA1. The distinctive features of this strain are alkalitolerance and halotolerance. The endoxylanase is active over a broad range of pH (5.0-10.0) and temperatures (30-100 °C) with optima at pH 7.5 and 70 °C, while ß-xylosidase is optimally active at pH 7.0 and 60 °C. The T 1/2 values of the endoxylanase and ß-xylosidase are 30 min at 80 °C, and 180 min at 70 °C, respectively. The endoxylanase activity is stimulated by dithiothreitol, but inhibited strongly by EDAC and Woodward's reagent K. N-BS and DEPC strongly inhibited ß-xylosidase. MALDI-ToF (MS/MS) analysis of tryptic digest of ß-xylosidase revealed similarity with that of G. thermodenitrificans NG 80-2, and suggested that this belongs to the GH 52 glycosyl hydrolase super family. The action of endoxylanase on birch wood xylan and agro-residues such as wheat bran and wheat straw liberated xylooligosaccharides similar to endoxylanases of the family 10 glycoside hydrolases, while the enzyme preparation having both endoxylanase and ß-xylosidase liberated xylose as main hydrolysis product.


Assuntos
Proteínas de Bactérias/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Geobacillus/enzimologia , Xilose/metabolismo , Xilosidases/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/efeitos dos fármacos , Fibras na Dieta , Ditiotreitol/farmacologia , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/efeitos dos fármacos , Estabilidade Enzimática , Etildimetilaminopropil Carbodi-Imida/farmacologia , Temperatura Alta , Concentração de Íons de Hidrogênio , Hidrólise , Isoxazóis/farmacologia , Cinética , Dados de Sequência Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Xilose/química , Xilosidases/química , Xilosidases/efeitos dos fármacos
19.
Appl Microbiol Biotechnol ; 97(14): 6279-92, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23132347

RESUMO

A gene encoding amylopullulanase (gt-apu) of the extremely thermophilic Geobacillus thermoleovorans NP33 was cloned and expressed in Escherichia coli. The gene has an open reading frame of 4,965 bp that encodes a protein of 1,655 amino acids with molecular mass of 182 kDa. The six conserved regions, characteristic of GH13 family, have been detected in gt-apu. The recombinant enzyme has only one active site for α-amylase and pullulanase activities based on the enzyme kinetic analyses in a system that contains starch as well as pullulan as competing substrates and response to inhibitors. The end-product analysis confirmed that this is an endoacting enzyme. The specific enzyme activities for α-amylase and pullulanase of the truncated amylopullulanase (gt-apuT) are higher than gt-apu. Both enzymes exhibited similar temperature (60 °C) and pH (7.0) optima, although gt-apuT possessed a higher thermostability than gt-apu. The overall catalytic efficiency (K(cat)/K(m)) of gt-apuT is greater than that of gt-apu, with almost similar substrate specificities. The C-terminal region of gt-apu appeared to be non-essential, and furthermore, it negatively affects the substrate binding and stability of the enzyme.


Assuntos
Proteínas de Bactérias/química , Geobacillus/enzimologia , Glicosídeo Hidrolases/química , Amido/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Estabilidade Enzimática , Geobacillus/química , Geobacillus/genética , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Temperatura Alta , Cinética , Dados de Sequência Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Especificidade por Substrato
20.
Bioprocess Biosyst Eng ; 36(5): 555-65, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-22932960

RESUMO

A novel bacterial isolate, capable of producing extracellular highly thermostable, halo-alkali-stable and cellulase-free xylanase, was isolated from soil and identified as Bacillus halodurans TSPV1 by polyphasic approach. The Plackett-Burman design identified wheat bran, lactose, tryptone and NaCl as the factors that significantly affect xylanase production, and thus, these were optimized by response surface methodology. The data analysis suggested that optimum levels of wheat bran (15-20 g L(-1)), lactose (1.0-1.5 g L(-1)), tryptone (2-2.5 g L(-1)) and NaCl (7.0-8.0 g L(-1)) support 6.75-fold higher xylanase production than that in the un-optimized medium. The xylanase is optimally active at 90 °C and pH 10, and stable for 4 h at 90 °C (T 1/2 60 h) over a broad range of NaCl concentrations (0-29 %). This is the first report on the isolation of polyextremophilic B. halodurans strain that produces thermo-halo-alkali-stable xylanase in submerged fermentation. This enzyme efficiently saccharifies agro residues like wheat bran and corncobs. Fifty-six percent of hemicellulose of wheat bran could be hydrolyzed by xylanase (100 U g(-1) substrate) along with cellulase (22 U FPase and 50 U CMCase g(-1)). The xylanase, being thermo-alkali stable and cellulase free, can find applications in pre-bleaching of paper pulps and hydrolysis of xylan in agricultural residues.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Bacillus/crescimento & desenvolvimento , Proteínas de Bactérias/química , Meios de Cultura/química , Fibras na Dieta , Endo-1,4-beta-Xilanases/química , Estabilidade Enzimática , Temperatura Alta , Concentração de Íons de Hidrogênio , Polissacarídeos/química , Polissacarídeos/metabolismo , Cloreto de Sódio/química
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