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1.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(3): 358-362, 2020 Mar 10.
Artigo em Chinês | MEDLINE | ID: mdl-32294835

RESUMO

Objective: To investigate the epidemiological and clinical characteristics of a case infected with avian influenza A (H5N6) virus associated with exposure to aerosol and provide evidence for the prevention and control of human infection with avian influenza virus. Methods: Epidemiological investigation was conducted to identify the history of exposure, infection route, and disease progression. Real-time fluorescent quantitative RT-PCR was used to test the samples collected from the case, close contacts, environment and poultry market. Results: The case had no history of exposure to live poultry and poultry market. But before the onset the case had a history of exposure to the live poultry placed in a car with doors and windows closed. The samples collected from the case's lower respiratory tract and the remaining frozen chicken meat were all influenza A (H5N6) virus positive. Conclusions: The source of infection was the live poultry, and the infection route might be the exposure to aerosol in a car with doors and windows closed, where the poultry were temporarily stored. It is necessary to promote centralized poultry slaughtering, cold chain distribution and fresh poultry sale, as well as strengthen health education and establish the concept of consuming fresh poultry.


Assuntos
Aerossóis/efeitos adversos , Vírus da Influenza A , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Animais , China/epidemiologia , Humanos , Aves Domésticas
2.
Zhonghua Xin Xue Guan Bing Za Zhi ; 47(12): 974-978, 2019 Dec 24.
Artigo em Chinês | MEDLINE | ID: mdl-31877593

RESUMO

Objective: To estimate the correlation between red cell distribution width (RDW) level and left atrial appendage thrombogenic milieu (LAATM) in elderly patients with non-valvular atrial fibrillation (NVAF). Methods: This was a retrospective case-control study. A total of 782 NVAF patients (age>60 years old) who finished transesophageal echocardiography (TEE) from January 2010 to December 2016 at Chaoyang Hospital was retrospectively screened, and diveded into LAATM group (n=65) and non LAATM group (n=717). RDW level was compared between the two groups. Potential association between RDW and LAATM was analyzed using multivariate logistic regression analysis. The accuracy of RDW for detecting LAATM was evaluated through receiver operating curve (ROC) analysis. Results: There were significant differences in age, history of heart failure, course of atrial fibrillation (AF), type of AF, NT-proBNP level, RDW level, left ventricular end systolic diameter, left ventricular end diastolic diameter, left ventricular ejection fraction (LVEF), left atrial diameter, CHADS(2) score and CHA(2)DS(2)-VASc score between the two groups (P<0.05). RDW level in LAATM group was significant higher than non LAATM group (13.4% (12.6%, 14.1%) vs. 12.1% (11.2%,13.0%), P<0.001). Multivariate logistic regression showed that RDW level associated with LAATM (OR=4.07, 95%CI 2.09-7.91, P<0.001). In ROC analysis, area under the curve was 0.81 (95%CI 0.74-0.88, P<0.001). When RDW level was 13.1%, LAATM could be diagnosed (sensitivity was 73.1% and specificity was 80.5%). Conclusions: RDW value is associated with the presence of LAATM in elderly NVAF patients. The RDW level has a certain reference value for predicting LAATM.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Idoso , Estudos de Casos e Controles , Ecocardiografia Transesofagiana , Índices de Eritrócitos , Eritrócitos , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos
3.
Zhonghua Nei Ke Za Zhi ; 58(6): 419-422, 2019 Jun 01.
Artigo em Chinês | MEDLINE | ID: mdl-31159519

RESUMO

Objective: To study the significance of Th17 cells in patients with myelodysplastic syndrome (MDS) and iron overload. Methods: A total of 77 patients with MDS admitted to Guangzhou First People's Hospital were enrolled from January 2017 to December 2018,who were divided into iron overload group (37 cases) with serum ferritin (SF) over 1000 µg/L and non-ferrous overload group(40 cases). CD(4)(+)T cells in peripheral blood (PB) and bone marrow (BM) were sorted by flow cytometry. The ratio of Th17 cells and cells with abnormal karyotype were compared. IL-17 and IL-6 protein and RNA expression were detected by ELISA and quantitative real-time PCR(qRT-PCR). Results: The proportions of Th17 cells in PB and BM in iron overload group were significantly higher than those in non-iron overload group [(41.06±0.96)% vs. (26.80±1.21)%; (47.39±1.60)% vs. (34.29±1.03)%; P<0.01]. The Th17 positive cells with abnormal karyotype in iron overload group were more than those in non-iron overload group[(4.96±0.53)% vs. (3.67±0.12)% in PB; (10.06±1.67)% vs. (4.36±0.43)% in BM; P<0.01]. Similarly,the protein levels as well as mRNA expression of IL-6 and IL-17 in patients with iron overload were significantly higher than those in non-iron overload group (P<0.01 both in PB and BM). Conclusions: As hematopoietic regulators secreted by Th17 cells, the expression of IL-6 and IL-17 in MDS patients with iron overload are elevated. This may predict the influence of these factors to the differentiation of Th17 cells.


Assuntos
Interleucina-17/imunologia , Interleucina-6/imunologia , Interleucinas/imunologia , Sobrecarga de Ferro , Síndromes Mielodisplásicas/sangue , Células Th17/imunologia , Medula Óssea , Primers do DNA/genética , Ensaio de Imunoadsorção Enzimática , Ferritinas/sangue , Citometria de Fluxo , Humanos , Interleucina-17/metabolismo , Interleucina-6/metabolismo , Interleucinas/metabolismo , Ferro/sangue , Síndromes Mielodisplásicas/imunologia , RNA , Reação em Cadeia da Polimerase em Tempo Real
4.
J Fish Dis ; 41(10): 1529-1538, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30039866

RESUMO

A disease with white spots in internal organs of Nile tilapia occurred in Zhanjiang, southern China. Multiple, white nodules, 0.8-2.2 mm in diameter, were scattered throughout the liver, spleen and kidney of diseased fish. Signs of nodules reproduced after artificial infection with the isolated strain. Isolated bacteria were Gram-negative, facultative anaerobic, motile, short rod-shaped, with a length of 1.2-2.2 µm. Morphological and biochemical tests, as well as phylogenetic analysis, all strongly indicated that the isolate from tilapia is identical to Aeromonas schubertii (A. schubertii) which temporary named LF1708 strain. Antibiotic sensitivity assays showed the LF1708 is sensitive to 24 of 27 tested antibiotics. Pathogenicity test revealed that the isolate at the dose of 3.75 × 106 CFU/g killed 100% of experimental tilapia within 2 days and the dose of 1 × 107 CFU/g killed 100% of experimental zebrafish within 1 day. Histopathology of diseased tilapia infected with A. schubertii showed numerous necrotic lesions widely distributed in spleen, liver and kidney, and infiltration with a large number of bacteria. To our knowledge, this was the first report that associated A. schubertii with mortality in tilapia.


Assuntos
Aeromonas/patogenicidade , Ciclídeos/microbiologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Necrose/veterinária , Aeromonas/efeitos dos fármacos , Aeromonas/genética , Aeromonas/crescimento & desenvolvimento , Animais , Antibacterianos/farmacologia , China , DNA Girase/genética , RNA Polimerases Dirigidas por DNA/genética , Doenças dos Peixes/mortalidade , Doenças dos Peixes/patologia , Pesqueiros , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Concentração de Íons de Hidrogênio , Rim/microbiologia , Rim/patologia , Fígado/microbiologia , Fígado/patologia , Necrose/microbiologia , Necrose/mortalidade , Filogenia , RNA Ribossômico 16S/genética , Salinidade , Baço/microbiologia , Baço/patologia , Peixe-Zebra/microbiologia
5.
Zhonghua Liu Xing Bing Xue Za Zhi ; 39(6): 799-804, 2018 Jun 10.
Artigo em Chinês | MEDLINE | ID: mdl-29936750

RESUMO

Objective: To investigate the infection pattern and etiological characteristics of a case of human infection with highly pathogenic avian influenza A (H7N9) virus and provide evidence for the prevention and control of human infection with highly pathogenic avian influenza virus. Methods: Epidemiological investigation was conducted to explore the case's exposure history, infection route and disease progression. Samples collected from the patient, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (RT-PCR). Virus isolation, genome sequencing and phylogenetic analysis were conducted for positive samples. Results: The case had no live poultry contact history, but had a history of pulled chicken processing without taking protection measure in an unventilated kitchen before the onset. Samples collected from the patient's lower respiratory tract, the remaining frozen chicken meat and the live poultry market were all influenza A (H7N9) virus positive. The isolated viruses from these positive samples were highly homogenous. An insertion which lead to the addition of multiple basic amino acid residues (PEVPKRKRTAR/GL) was found at the HA cleavage site, suggesting that this virus might be highly pathogenic. Conclusions: Live poultry processing without protection measure is an important infection mode of "poultry to human" transmission of avian influenza viruses. Due to the limitation of protection measures in live poultry markets in Guangzhou, it is necessary to promote the standardized large scale poultry farming, the complete restriction of live poultry sales and centralized poultry slaughtering as well as ice fresh sale.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/transmissão , Influenza Humana/virologia , Aves Domésticas/virologia , Animais , Galinhas , China , Comércio , Humanos , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Influenza Aviária/prevenção & controle , Influenza Humana/prevenção & controle , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Zoonoses
6.
Vet Microbiol ; 211: 67-73, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29102124

RESUMO

Nocardiosis afflicts multiple species of cultured fish, resulting in substantial economic losses to the aquaculture industry, however, lack of detailed knowledge on disease pathogenesis has hampered the development of effective prevention and control strategies. In this study, we injected a green fluorescent protein (GFP)-labeled Nocardia seriolae strain into a transparent mutant strain of Tiger barb (Puntius tetrazona) to monitor tissue pathogen accumulation and tissue damage in vivo, and to clarify the relationship between pathogenic processes and overt symptoms. GFP-labeled bacteria were phagocytized by leukocytes and could proliferate within these cells, which in turn led to leukocyte aggregation, leukocyte death, and granuloma formation. In addition, intracellular bacteria could permanently colonize various tissues via leukocyte circulation, causing multi-organ infection as revealed by changes of tissue transparency. Histology revealed granulomatous lesions in organs such as muscle, kidney, and spleen that was corresponded to the tissue opacities in vivo. Confocal microscopy confirmed massive accumulations of GFP-labeled bacteria within these granulomas, which often contained a necrotic core. Tiger barb transparency allows for real-time observation of in vivo pathological changes within the same animal, and the pathogenic process can be evaluated based on the shape and size of body opacities. Thus, transparent Tiger barb is a promising model to study the pathogenesis of nocardiosis.


Assuntos
Cyprinidae/microbiologia , Modelos Animais de Doenças , Doenças dos Peixes/patologia , Nocardiose/veterinária , Nocardia/fisiologia , Animais , Aquicultura , Doenças dos Peixes/microbiologia , Nocardiose/microbiologia , Nocardiose/patologia
7.
Zhonghua Nei Ke Za Zhi ; 55(12): 932-936, 2016 Dec 01.
Artigo em Chinês | MEDLINE | ID: mdl-27916047

RESUMO

Objective: To investigate the effects of different doses of atorvastatin on plasma endothelin and platelet function in acute ST-segment elevation myocardial infarction (STEMI) patients after emergency percutaneous coronary intervention(PCI). Methods: A total of 120 patients with acute STEMI treated with emergency PCI were enrolled and randomly divided into 20 mg of atorvastatin treatment group (standard group, n=60), and 40 mg of atorvastatin treatment group (intensive group, n=60). The blood C reactive protein (CRP), blood lipid profiles, plasma endothelin (ET) were measured before atorvastatin treatment and after 7 days of treatment, respectively. The platelet fibrin clot strength induced by ADP (MAADP) was determined by thrombelastography(TEG). Results: Seven days after of atorvastatin treatment, the level of plasma ET in intensive group was significantly lower than that in standard group [(0.49±0.21)pmol/L vs (0.63±0.58)pmol/L, P<0.05]. Moreover, the MAADP in intensive group was significantly decreased compared with the standard group [(38.4±17.4) mm vs (45.7±14.5) mm, P<0.05]. There was a positive correlation between the ET level and MAADP in intensive group after treatment (r=0.378, P<0.05). However, no significantly differences could be viewed in the CRP and LDL-C levels between the two groups (P>0.05). Conclusion: In patients with acute STEMI, early administration of 40 mg atorvastatin after emergency PCI could significantly reduce the vascular endothelial injury, improve endothelial function, and reduce the residual platelet activity.


Assuntos
Anticolesterolemiantes/administração & dosagem , Atorvastatina/administração & dosagem , Endotelinas/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/cirurgia , Intervenção Coronária Percutânea , Doença Aguda , Idoso , Anticolesterolemiantes/farmacologia , Anticolesterolemiantes/uso terapêutico , Atorvastatina/farmacologia , Atorvastatina/uso terapêutico , Plaquetas , Proteína C-Reativa/metabolismo , Relação Dose-Resposta a Droga , Endotelinas/sangue , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Resultado do Tratamento
8.
Zhonghua Yi Xue Za Zhi ; 96(21): 1699-701, 2016 Jun 07.
Artigo em Chinês | MEDLINE | ID: mdl-27290714

RESUMO

OBJECTIVE: Use epidemiological approaches to investigate the correlation between the siesta and blood pressure. METHOD: From March 1(st,) 2011 to June 30(th) 2013, a total of 950 people were collected from East Jiaozhou Qingdao region using variable sampling methods including stratified method, the entire group method, random and proportional methods. Medical professionals conducted a person-to-person survey, collecting the data and inputting it into computers, after which a database was established using STATA 12.0. We analyzed the correlation between the siesta time and blood pressure/hypertension by using rank correlation method (Spearman). Logistic regression method was used to analyze the relationship between high blood pressure and different time and habit of the siesta after adjusting age, sex and BMI. RESULTS: There was a negative correlation between the time of siesta and the systolic pressure with r=-0.18, P<0.001; there was no relationship between the time of siesta and the diastolic pressure with r=-0.07, P=0.02; also, there is a negative correlation between the time of siesta and the hypertension morbidity, with r=-0.22, P<0.001. In the Logistic regression analysis about the period of time to take a nap and the risk of hypertension, it was found that the relative risk factors for hypertension were more than 60-year-old, BMI >25 kg/m(2) and no siesta habits. CONCLUSIONS: The time of siesta is negatively correlated to the systolic pressure, rather than the diastolic pressure, and it can generally reduce the incidence of hypertension. The relative risk factors of hypertension are more than 60-year-old, BMI >25 kg/m(2) and no siesta habits in all four seasons. We recommend that take a nap a day, or it might be even better for systolic blood pressure to take longer siesta.


Assuntos
Pressão Sanguínea/fisiologia , Hipertensão/epidemiologia , Descanso/fisiologia , Sono/fisiologia , China/epidemiologia , Estudos Epidemiológicos , Humanos , Hipertensão/fisiopatologia , Incidência , Modelos Logísticos , Fatores de Risco , Inquéritos e Questionários
9.
Euro Surveill ; 19(25)2014 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-24993555

RESUMO

We investigated a possible person-to-person transmission within a family cluster of two confirmed influenza A(H7N9) patients in Guangzhou, China. The index case, a man in his late twenties, worked in a wet market that was confirmed to be contaminated by the influenza A(H7N9) virus. He developed a consistent fever and severe pneumonia after 4 January 2014. In contrast, the second case, his five-year-old child, who only developed a mild disease 10 days after disease onset of the index case, did not have any contact with poultry and birds but had unprotected and very close contact with the index case. The sequences of the haemagglutinin (HA) genes of the virus stains isolated from the two cases were 100% identical. These findings strongly suggest that the second case might have acquired the infection via transmission of the virus from the sick father. Fortunately, all 40 close contacts, including the other four family members who also had unprotected and very close contact with the cases, did not acquire influenza A(H7N9) virus infection, indicating that the person-to-person transmissibility of the virus remained limited. Our finding underlines the importance of carefully, thoroughly and punctually following-up close contacts of influenza A(H7N9) cases to allow detection of any secondary cases, as these may constitute an early warning signal of the virus's increasing ability to transmit from person-to-person.


Assuntos
Genoma Viral/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/transmissão , Influenza Humana/transmissão , Adulto , Animais , Pré-Escolar , China , Busca de Comunicante , Exposição Ambiental , Família , Feminino , Humanos , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Influenza Humana/virologia , Masculino , Filogenia , Vigilância da População , Aves Domésticas , Análise de Sequência de DNA
10.
J Fish Biol ; 80(7): 2393-404, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22650423

RESUMO

A transparent mutant tiger barb Puntius tetrazona was identified and characterized by its transparent body, which allows clear visualization of internal organs. Hybridization of this mutant with the albino variant produces a transparent and albinoid double phenotype, and the transparency of this mutant is controlled by a recessive allele. Light microscopic and ultrastructural examinations show that in contrast to normal individuals, transparent mutants lack iridophores, and light penetrates unimpeded through the body. Pleistophora sp. infection was observed in vivo, allowing live observation of parasite dissemination and the consequent pathological alterations in the fish body as well as the simultaneous acquisition of data on the dynamics and spatial pattern of pathogenic invasion. It is superior to common fish models, as dynamic experimental data can be obtained from individual fish.


Assuntos
Albinismo/veterinária , Cyprinidae/genética , Doenças dos Peixes/patologia , Microsporidiose/veterinária , Mutação , Albinismo/genética , Albinismo/microbiologia , Animais , Cromatóforos , Cyprinidae/microbiologia , Doenças dos Peixes/microbiologia , Microsporídios , Microsporidiose/patologia , Pigmentação/genética
13.
J Magn Reson ; 134(1): 161-3, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9740743

RESUMO

We have developed a two-dimensional maximum entropy spectrum reconstruction program designed to run in parallel on workstation clusters. Test reconstructions of planes extracted from a three-dimensional NMR data set indicate that the parallel speedup is nearly equal to the number of processors provided that the individual processors have comparable performance and that there are at least as many planes as processors. The program also works well in a typical laboratory setting consisting of heterogeneous workstations.


Assuntos
Processamento de Imagem Assistida por Computador , Ressonância Magnética Nuclear Biomolecular/métodos , Algoritmos , Gráficos por Computador , Entropia , Software
14.
J Chem Inf Comput Sci ; 37(3): 467-77, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9177001

RESUMO

A sequential assignment protocol for proteins was developed using heteronuclear 3D NMR. The protocol consists of an amino acid type recognition algorithm and a primary sequence mapping algorithm. The former measures the similarity between each detected spin pattern and 20 standard amino acid coupling patterns. Both chemical shift and topologically likeness are considered. The mapping algorithm uses the amino acid type information to direct detected polypeptides to proper position onto protein primary sequence. The assignment protocol can be applied to spin systems generated by many different approaches. We designed a few computer programs to derive a protein's backbone and side chain spin systems using heteronuclear 3D NMR. The results was then input to the sequential assignment protocol. All of the algorithms were tested on NMR data of a 90-residue N-domain of chicken skeletal troponin-C.


Assuntos
Algoritmos , Espectroscopia de Ressonância Magnética/métodos , Proteínas/química , Software , Sequência de Aminoácidos , Animais , Galinhas , Dados de Sequência Molecular , Estrutura Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Mapeamento de Peptídeos , Proteínas/genética , Troponina C/química , Troponina C/genética
15.
Vox Sang ; 62(2): 98-101, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1325715

RESUMO

The reference range of serum alanine amino transferase (ALT) for the local population was established by testing 5,000 random voluntary Chinese blood donors of various age groups of both sexes. In addition, 1,769 serum samples with elevated ALT levels were also collected for anti-HCV assays using both the Abbott and Ortho anti-hepatitis C virus (HCV) assay kits. The relationship between serum ALT and anti-HCV tests was studied and the performances of both kits used were compared. It was found that while the prevalence of serum anti-HCV was 0.4% among hepatitis B surface antigen-negative donors with normal ALT, subjects with ALT between 2 and 3 standard deviations (SD) and greater than 3 SD above the mean level had respective prevalence of anti-HCV 3 and 9.5 times that of the normal ALT subjects. Both anti-HCV kits were found to identify in majority the same positive population among the different groups of subjects studied. In addition, it was observed that for subjects who were anti-HCV-positive, the higher the serum ALT level, the higher the mean anti-HCV ELISA ratio and this observation was similar for both anti-HCV kits used. We conclude that: (1) there is a direct relationship between serum ALT level and anti-HCV positivity by EIA; (2) there is a direct correlation between serum ALT level and anti-HCV ELISA ratio, and (3) both Abbott and Ortho anti-HCV kits perform similarly in the identification of positive serum samples.


Assuntos
Alanina Transaminase/sangue , Doadores de Sangue , Hepacivirus/imunologia , Anticorpos Anti-Hepatite/sangue , Hepatite C/epidemiologia , Adulto , Biomarcadores/sangue , Portador Sadio/diagnóstico , Ensaio de Imunoadsorção Enzimática , Feminino , Hepatite C/diagnóstico , Hong Kong/epidemiologia , Humanos , Masculino , Programas de Rastreamento , Prevalência , Kit de Reagentes para Diagnóstico
16.
Microbiol Immunol ; 35(4): 289-301, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1943842

RESUMO

Respiratory deficient (res-) mutants of E. coli are slow growing microcolonial, anaerobic, catalase and benzidine negative strains whose broad phenotypic alteration may result from pleiotropic mutations in genes of the hemin biosynthetic pathway. They are easily recovered from platings of sensitive cells on concentrations of gentamicin higher than the minimal inhibitory concentration. These mutants show a dramatic change in their biochemical diagnostic profile resulting primarily from deficiencies in the active transport mechanisms of the cell. Using well-marked F- and Hfr strains, 157 mutants were analyzed from 3 different parent strains; all but 2 resulted from mutations in 3 loci of the hemin biosynthetic pathway. Of these a marked skew to hemB- mutations was seen, with more than 80% mapping there. The possibility that this hot spot resulted from transpositional activity was tested by Southern hybridization of EcoRI digests of the chromosomal DNA, using as a probe, a 2.8-kb fragment containing the hemB gene. The WT and other hemB+ control strains contained a 14.6-kb fragment. Of 18 hemB strains tested, 14 showed deletion and insertion mutations which fell into four classes based on the variation in the size of the fragment or on the absence of hybridization. The latter resulted from complete deletion of the hemB gene. An increase in fragment size from 1.5-kb to 3.4-kb was observed in some of the strains.


Assuntos
Escherichia coli/genética , Genes Bacterianos/genética , Hemina/genética , Mutação , Aminoglicosídeos , Antibacterianos/farmacologia , Deleção Cromossômica , Mapeamento Cromossômico , Análise Mutacional de DNA , Resistência Microbiana a Medicamentos , Escherichia coli/efeitos dos fármacos , Oxirredutases/genética
17.
Appl Environ Microbiol ; 46(6): 1380-7, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6419677

RESUMO

Lactobacillus acidophilus IFO 3532 was found to produce only intracellular alpha-glucosidase (alpha-D-glucoside glucohydrolase; EC 3.2.1.20). Maximum enzyme production was obtained in a medium containing 2% maltose as inducer at 37 degrees C and at an initial pH of 6.5. The enzyme was formed in the cytoplasm and accumulated as a large pool during the logarithmic growth phase. Enzyme production was strongly inhibited by 4 microM CuSO4, 40 microM CoCl2, and beef extract; MnSO4 and the presence of proteose peptone and yeast extract in the medium greatly enhanced enzyme production. A 16.6-fold purification of alpha-glucosidase was achieved by (NH4)2SO4 fractionation and DEAE-cellulose column chromatography. The enzyme showed high specificity for maltose. The Km for alpha-p-nitrophenyl-beta-D-glucopyranoside was 11.5 mM, and the Vmax for alpha-p-nitrophenyl-beta-D-glucopyranoside hydrolysis was 12.99 mumol/min per mg of protein. The optimal pH and temperature for enzyme activity were 5.0 and 37 degrees C, respectively. The enzyme activity was inhibited by Hg2+, Cu2+, Ni2+, Zn2+, Ca2+, Co2+, urea, rose bengal, and 2-iodoacetamide, whereas Mn2+, Mg2+, L-cysteine, L-histidine, Tris, and EDTA stimulated enzyme activity. Transglucosylase activity was present in the partially purified enzyme, and isomaltose was the only glucosyltransferase product. Amylase activity in the purified preparation was relatively weak, and no isomaltase activity was detected.


Assuntos
Glucosidases/biossíntese , Lactobacillus acidophilus/enzimologia , alfa-Glucosidases/biossíntese , Carboidratos/farmacologia , Cátions , Citoplasma/enzimologia , Concentração de Íons de Hidrogênio , Temperatura , Ureia/farmacologia , alfa-Glucosidases/metabolismo
18.
Microbios ; 32(127): 47-61, 1981.
Artigo em Inglês | MEDLINE | ID: mdl-6803101

RESUMO

Lactobacillus acidophilus NCTC 1723 produced intracellular and extracellular alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20). The alpha-glucosidase was partially purified by ammonium sulphate fractionation and DEAE-cellulose column chromatography, and attained a 10.3-fold purification. The Km for alpha-PNPG was 2.9 mM and the Vmax for alpha-PNPG hydrolysis was 6.45 mumole ml-1 min-1. The enzyme was stable only at pH 6.0-7.5 while incubated at 25 degrees C. At pH 6.5, a 100% activity was retained at 15 degrees-37 degrees C. However, the enzyme was easily destroyed at 50 degrees C. The pH optimum for stability of the enzyme at low temperature (2 degrees C) was between 5 and 6. It was found that addition of Mn++, Ba++ and EDTA, to the medium stimulated alpha-glucosidase activity, while the presence of Hg++, Cu++, Co++, Ni++, Zn++, L-histidine, arabitol, erythritol, sorbitol and glycerol inhibited enzyme activity. Although isomaltase activity was found in the partially purified alpha-glucosidase, it was not known whether this activity was an intrinsic capability of the enzyme. Transglucosylase and weak glucoamylase activities were also found to associate with the partially purified alpha-glucosidase. Since only the alpha-1,6 linked isomaltose was detected as the transferase product, it was thought that the alpha-glucosidase was capable of glucosyl transfer via alpha-1,6-glucosidic bonds.


Assuntos
Glucosidases/análise , Lactobacillus acidophilus/enzimologia , alfa-Glucosidases/análise , Glucana 1,4-alfa-Glucosidase/análise , Concentração de Íons de Hidrogênio , Isomaltose/análise , Cinética , Temperatura , alfa-Glucosidases/isolamento & purificação
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