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1.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(5): 513-520, 2023 May 24.
Artigo em Chinês | MEDLINE | ID: mdl-37198123

RESUMO

Objective: To compare the prognosis of mildly or severely symptomatic patients with obstructive hypertrophic cardiomyopathy (OHCM) who underwent alcohol septal ablation (ASA). Methods: This retrospective study cohort consisted of patients with OHCM who received ASA treatment in Beijing Anzhen Hospital, Capital Medical University from March 2001 to August 2021. These patients were divided into mildly and severely symptomatic groups according to the severity of clinical symptoms. Long-term follow-up was conducted, and the following data were collected: duration of follow-up, postoperatire treatment, New York Heart Association (NYHA) classification, arrhythmia events and pacemaker implantation, echocardiographic parameters, and cause of death. Overall survival and survival free from OHCM-related death were observed, and the improvement of clinical symptoms and resting left ventricular outflow tract gradient (LVOTG) and the incidence of new-onset atrial fibrillation were evaluated. The Kaplan-Meier method and log-rank test were used to determine and compare the cumulative survival rates of the different groups. Cox regression analysis models were used to determine predictors of clinical events. Results: A total of 189 OHCM patients were included in this study, including 68 in the mildly symptomatic group and 121 in the severely symptomatic group. The median follow-up of the study was 6.0 (2.7, 10.6) years. There was no statistical difference in overall survival between the mildly symptomatic group (5-year and 10-year overall survival were 97.0% and 94.4%, respectively) and the severely symptomatic group (5-year and 10-year overall survival were 94.2% and 83.9%, respectively, P=0.405); there was also no statistical difference in survival free from OHCM-related death between the mildly symptomatic group (5-year and 10-year survival free from HCM-related death were 97.0% and 94.4%, respectively) and the severely symptomatic group (5-year and 10-year survival free from HCM-related death were 95.2% and 92.6%, respectively, P=0.846). In the mildly symptomatic group, NYHA classification was improved after ASA (P<0.001), among which 37 patients (54.4%) were in NYHA class Ⅰ, and the resting left ventricular outflow tract gradient (LVOTG) decreased from 67.6 (42.7, 90.1) mmHg (1 mmHg=0.133 kPa) to 24.4 (11.7, 35.6) mmHg (P<0.001). In severely symptomatic group, NYHA classification was also improved post ASA (P<0.001), among which 96 patients (79.3%) improved by at least one NYHA classification, and the resting LVOTG decreased from 69.6 (38.4, 96.1) mmHg to 19.0 (10.6, 39.8) mmHg (P<0.001). The incidence of new-onset atrial fibrillation was similar between the mildly and severely symptomatic groups (10.2% vs. 13.3%, P=0.565). Cox multivariate regression analysis showed that age was an independent predictor of all-cause mortality in OHCM patients post ASA (HR=1.068, 95%CI 1.002-1.139, P=0.042). Conclusions: Among patients with OHCM treated with ASA, overall survival and survival free from HCM-related death were similar between mildly symptomatic group and severely symptomatic group. ASA therapy can effectively relieve resting LVOTG and improve clinical symptoms in mildly or severely symptomatic patients with OHCM. Age was an independent predictor of all-cause mortality in OHCM patients post ASA.


Assuntos
Fibrilação Atrial , Cardiomiopatia Hipertrófica , Humanos , Estudos Retrospectivos , Septos Cardíacos/cirurgia , Resultado do Tratamento , Cardiomiopatia Hipertrófica/cirurgia
2.
J Dent Res ; 100(10): 1109-1117, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34334009

RESUMO

To establish an ideal microenvironment for regenerating maxillofacial defects, recent research interests have concentrated on developing scaffolds with intricate configurations and manipulating the stiffness of extracellular matrix toward osteogenesis. Herein, we propose to infuse a degradable RGD-functionalized alginate matrix (RAM) with osteoid-like stiffness, as an artificial extracellular matrix, to a rigid 3D-printed hydroxyapatite scaffold for maxillofacial regeneration. The 3D-printed hydroxyapatite scaffold was produced by microextrusion technology and showed good dimensional stability with consistent microporous detail. RAM was crosslinked by calcium sulfate to manipulate the stiffness, and its degradation was accelerated by partial oxidation using sodium periodate. The results revealed that viability of bone marrow stem cells was significantly improved on the RAM and was promoted on the oxidized RAM. In addition, the migration and osteogenic differentiation of bone marrow stem cells were promoted on the RAM with osteoid-like stiffness, specifically on the oxidized RAM. The in vivo evidence revealed that nonoxidized RAM with osteoid-like stiffness upregulated osteogenic genes but prevented ingrowth of newly formed bone, leading to limited regeneration. Oxidized RAM with osteoid-like stiffness facilitated collagen synthesis, angiogenesis, and osteogenesis and induced robust bone formation, thereby significantly promoting maxillofacial regeneration. Overall, this study supported that in the stabilized microenvironment, oxidized RAM with osteoid-like stiffness offered requisite mechanical cues for osteogenesis and an appropriate degradation profile to facilitate bone formation. Combining the 3D-printed hydroxyapatite scaffold and oxidized RAM with osteoid-like stiffness may be an advantageous approach for maxillofacial regeneration.


Assuntos
Osteogênese , Alicerces Teciduais , Regeneração Óssea , Diferenciação Celular , Oligopeptídeos , Impressão Tridimensional
3.
Zhonghua Xin Xue Guan Bing Za Zhi ; 48(9): 765-771, 2020 Sep 24.
Artigo em Chinês | MEDLINE | ID: mdl-32957760

RESUMO

Objective: To investigate the effects of clopidogrel resistence and CYP2C19 genotype on the clinical prognosis of acute coronary syndrome(ACS) patients undergoing percutaneous coronary intervention(PCI). Methods: This study was a retrospective cohort study. ACS patients who underwent PCI in Beijing Anzhen Hospital from October 2015 to January 2017 were recruited. The inhibition rate of adenosine diphosphate(ADP) was monitored by thromboelastography. All of these patients were divided into clopidogrel resistance and non-resistance group according to the monitoring results. CYP2C19 genotype was detected by TaqMan probe-based real-time quantitative PCR. Patients were divided into slow, medium and fast metabolic group, according to the CYP2C19 genotype. After 12 months of follow-up, the end points included all-cause death, cardiac death, angina, myocardial infarction, stent thrombosis, ischemic stroke and hemorrhage were collected. Combined thrombotic events were defined as a composite of angina, myocardial infarction, stent thrombosis and ischemic stroke. The differences of the incidence of clinical events between groups were compared. Cox regression was used to analyze the effects of clopidogrel resistance and CYP2C19 genotype on the combined thrombotic events, cardiac death and hemorrhage. Results: A total of 1 696 patients were included, and the age was (59.4±9.6) years, with 1 280(75.5%) males. There were 471 cases(27.8%) in clopidogrel resistance group, and 1 225 cases(72.2%) in clopidogrel non-resistance group. There were 218 patients(12.9%) were in slow metabolic group, 668(39.4%) in medium metabolic group, and 810 (47.8%) in fast metabolic group. The median follow-up time was 13.3 months, and 131 cases were lost to follow-up, with a loss follow-up rate of 7.7%. Compared with the clopidogrel non-resistance group, the clopidogrel resistance group had a higher incidence of myocardial infarction(7.6%(36/471) vs. 5.1%(62/1 225), P=0.041), a lower incidence of hemorrhage (13.2%(62/471) vs. 17.9%(219/1 225), P=0.020) and minor hemorrhage(11.5%(54/471) vs. 15.8% (194/1 225), P=0.022). There were no statistically significant difference in all-cause death, cardiac death, angina, stent thrombosis, ischemic stroke and severe bleeding between clopidogrel resistance and non-resistance group(all P>0.05). There was no statistically significant difference in the incidence of endpoint events among different CYP2C19 genotypes (all P>0.05). Cox regression analysis showed that clopidogrel resistance was an independent factor of combined thrombotic events (OR=2.334, 95%CI 1.215-4.443, P=0.016) and bleeding events (OR=0.481, 95%CI 0.174-0.901, P=0.023). While CYP2C19 genotype was not independent factor for combined thrombotic events, cardiac death and hemorrhage (all P>0.05). Conclusion: For ACS patients after PCI, clopidogrel resistance can increase the risk of combined thrombotic events, but also reduce the risk of bleeding; while CYP2C19 genotype is not an independent factor for clinical prognosis.


Assuntos
Síndrome Coronariana Aguda , Clopidogrel , Intervenção Coronária Percutânea , Inibidores da Agregação Plaquetária , Síndrome Coronariana Aguda/tratamento farmacológico , Síndrome Coronariana Aguda/genética , Clopidogrel/farmacologia , Clopidogrel/uso terapêutico , Citocromo P-450 CYP2C19/genética , Genótipo , Humanos , Masculino , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
4.
Zhonghua Yi Xue Za Zhi ; 99(39): 3089-3092, 2019 Oct 22.
Artigo em Chinês | MEDLINE | ID: mdl-31648453

RESUMO

Objective: To evaluate the clinical values of 4 types of ceramides (Cer1, Cer2, Cer3, Cer4) in the coronary artery stenosis, clinical diagnosis and risk prediction. Methods: A total of 890 patients with coronary heart disease (CHD) in Beijing Anzhen Hospital between March 2018 and August 2018 were enrolled. The relationships between different degrees of coronary artery stenosis and ceramide levels was investigated. Diagnostic value of ceramides on acute myocardial infarction was analyzed. Meanwhile, Major adverse cardiac and cerebrovascular events (MACCE) in 1 year after discharging were collected to evaluate the predictive value of ceramides on risk of CHD and stroke. Results: This study showed that there were no significant differences of ceramide levels in CHD patients with different degrees of coronary artery stenosis (P>0.05), and the area under receiver operating characteristic (ROC) curve in the diagnosis of acute myocardial infarction patients was 0.725. Conclusions: Ceramide is proved to be helpful in the diagnosis of acute myocardial infarction and MACCE prediction. The relationships between ceramide and degrees of coronary artery stenosis as well as the prognosis of CHD need further elucidation.


Assuntos
Doença da Artéria Coronariana , Estenose Coronária , Infarto do Miocárdio , Acidente Vascular Cerebral , Ceramidas , Humanos
5.
Oncogene ; 37(1): 116-127, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-28892050

RESUMO

Aberrant protein glycosylation could be a distinct surface-marker of cancer cells that influences cancer progression and metastasis because glycosylation can regulate membrane protein folding which alters receptor activation and changes epitope exposure for antibody (Ab) recognition. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), a glycophosphoinositol-anchored protein, is a heavily glycosylated tumor antigen. However, the clinical significance and biological effect of CEACAM6 glycosylation has not been addressed in cancers. We recently developed an anti-CEACAM6 Ab (TMU) from an immune llama library which can be engineered to a single-domain (sd)Ab or a heavy-chain (HC)Ab. The TMU HCAb specifically recognized glycosylated CEACAM6 compared to the conventional antibodies. Using the TMU HCAb, we found that glycosylated CEACAM6 was a tumor marker associated with recurrence in early-stage OSCC (oral squamous cell carcinoma) patients. CEACAM6 promoted OSCC cell invasion, migration, cytoskeletal rearrangement, and metastasis via interaction with epidermal growth factor (EGF) receptor (EGFR) and enhancing EGFR activation, clustering and intracellular signaling cascades. These functions were modulated by N-acetylglucosaminyltransferase 5 (MGAT5) which mediated N-glycosylation at Asn256 (N256) of CEACAM6. Finally, the TMU sdAb and HCAb treatment inhibited the migration, invasion and EGF-induced signaling in CEACAM6-overexpressing cells. In conclusion, the complex N-glycosylation of CEACAM6 is critical for EGFR signaling of OSCC invasion and metastasis. Targeting glycosylated CEACAM6 with the TMU sdAb or TMU HCAb could be a feasible therapy for OSCC.


Assuntos
Antígenos CD/metabolismo , Carcinoma de Células Escamosas/patologia , Moléculas de Adesão Celular/metabolismo , Receptores ErbB/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Bucais/patologia , Recidiva Local de Neoplasia/patologia , Adulto , Animais , Antígenos CD/genética , Asparagina/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/secundário , Moléculas de Adesão Celular/genética , Linhagem Celular Tumoral , Movimento Celular , Receptores ErbB/genética , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Glicosilação , Humanos , Neoplasias Pulmonares/secundário , Masculino , Camundongos , Camundongos SCID , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Invasividade Neoplásica/patologia , Estadiamento de Neoplasias , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Oncogene ; 36(14): 1978-1990, 2017 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-27748761

RESUMO

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. Despite the availability of several treatment strategies, resistance to chemotherapeutic agents, which limits the effectiveness of anticancer drugs, is a major problem in cancer therapy. In this study, we used a histone deacetylases inhibitor (HDACi) to establish drug-resistant HCC cells and further analyzed the molecular mechanisms underlying the development of resistance in HCC cells. Compared with the parental cells, HDACi-resistant cells showed high metastatic and pro-survival abilities. Two-dimensional electrophoresis data showed that the cofilin-1 (CFL-1) protein was altered in HDACi-resistant cells and was highly expressed in resistant cells compared with parental cells. The molecular function of CFL-1 is actin depolymerization, and it is involved in tumor metastasis. In this study, we showed that CFL-1 inhibition decreased cell migration and increased cell apoptosis in HDACi-resistant cells. We observed that HDACi induced ROS accumulation in cells and apoptosis via promotion of the CFL-1 interaction with Bax and CFL-1 translocation to the mitochondria, resulting in cytochrome C release. Importantly, phosphorylation of CFL-1 by activated extracellular signal-regulated kinases 1 and 2 (ERK1/2) confers strong protection against HDAC inhibitor-induced cell injury. p-CFL-1 shows a loss of affinity with Bax and will not translocate to mitochondria, stably remaining in the cytoplasm. These results indicate that phosphorylation to inactivate CFL-1 decreased the chemosensitivity to HDAC inhibitors and resulting in drug resistance of HCC cells.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Cofilina 1/metabolismo , Resistencia a Medicamentos Antineoplásicos , Inibidores de Histona Desacetilases/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Espécies Reativas de Oxigênio/toxicidade , Animais , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Nus , Mitocôndrias/metabolismo , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células Tumorais Cultivadas
7.
Bull Entomol Res ; 105(5): 607-14, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26082426

RESUMO

Necrophoric behaviour is critical sanitation behaviour in social insects. However, little is known about the necrophoric responses of workers towards different developmental stages in a colony as well as its underlying mechanism. Here, we show that Solenopsis invicta workers display distinct necrophoric responses to corpses of workers and pupae. Corpses of workers killed by freezing (dead for <1 h) were carried to a refuse pile, but pupal corpses would take at least 1 day to elicit workers' necrophoric response. Metarhizium anisopliae-infected pupal corpses accelerated the necrophoric behaviour of resident workers, with 47.5% of unaffected corpses and 73.8% infected corpses discarded by 1 day post-treatment). We found that fungus-infected pupal corpses had a higher concentration of fatty acids (palmitic acid, oleic acid and linoleic acid) on their surface. We experimentally confirmed that linoleic and oleic acids would elicit a necrophoric response in workers. The appearance of linoleic and oleic acids appeared to be chemical signals involved in recognition of pupal corpses, and M. anisopliae infection could promote the accumulation of fatty acids on surface of pupal corpses resulting in accelerated necrophoric responses of workers.


Assuntos
Formigas/microbiologia , Comportamento Animal , Animais , Formigas/fisiologia , Comportamento Animal/efeitos dos fármacos , Interações Hospedeiro-Patógeno , Ácidos Linoleicos/farmacologia , Ácidos Oleicos/farmacologia , Pupa/microbiologia , Comportamento Social
8.
Vet Parasitol ; 203(3-4): 318-21, 2014 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-24813744

RESUMO

Toxoplasma gondii can infect a wide variety of warm-blooded animals, including bats. Limited information on T. gondii infection in bats is available in China. The objective of the present study was to determine prevalence and genetic diversity of T. gondii infection in bats in southern China. A total of 608 bats representing 12 species, including 120 Aselliscus stoliczkanus, 59 Myotis chinensis, 11 Miniopterus schreibersii, 53 Rhinolophus affinis, 32 Rhinolophus pusillus, 81 Hipposideros armiger, 28 Hipposideros fulvus, 32 Cynopterus brachyotis, 14 Cynopterus sphinx, 45 Eonycteris spelaea, 109 Hipposideros larvatus, and 24 Taphozous melanopogon, were collected from Yunnan and Guangxi provinces, southern China. They were examined for the presence of T. gondii DNA by amplification of the B1 gene using a nested PCR, and the positive samples were genotyped at 11 genetic loci (SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) using multilocus polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Fifty-nine (9.7%) of these bats were detected positive by PCR but only five of these positive DNA samples were completely typed at all loci; of which 4 samples, 2 from A. stoliczkanus, and 2 from H. larvatus, belonged to ToxoDB Genotype #10, and the other one from H. larvatus was identified as ToxoDB Genotype #9 (http://toxodb.org/toxo/). To our knowledge, this is the first report of molecular detection and genetic characterization of T. gondii infection in bats in China. The results show that these bats are potential reservoirs for T. gondii transmission, which may pose a threat to human health.


Assuntos
Quirópteros/parasitologia , Variação Genética , Toxoplasma/genética , Toxoplasmose Animal/epidemiologia , Animais , China/epidemiologia , Reservatórios de Doenças/parasitologia , Genes de Protozoários/genética , Genótipo , Reação em Cadeia da Polimerase , Prevalência , Toxoplasmose Animal/parasitologia
9.
Ann Trop Med Parasitol ; 104(1): 73-80, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20149294

RESUMO

As there appeared to be no data available on Toxocara canis infection in the children of Swaziland, a serological survey of T. canis infection was recently conducted among 92 children aged 3-12 years from rural slums in the low- and middle-veld. A child was considered seropositive if, in western blots based on the excretory-secretory antigens of larval T. canis, his or her serum gave a positive result when diluted 1 : 64. Forty-one (44.6%) of the children were found seropositive. There were no statistically significant differences in seroprevalence between the 49 boys and 43 girls investigated (46.9% v. 41.8%) or between the eight subjects aged 12 years and the 47 aged < or = 5 years (62.5% v. 38.3%); the corresponding odds ratios were 0.81 (95% confidence interval=0.36-1.86; P=0.62) and 2.69 (95% confidence interval=0.57-12.62; P=0.20), respectively. The 66 subjects from the middleveld were, however, significantly more likely to be seropositive than the 26 subjects from the lowveld (54.5% v. 19.2%; odds ratio=5.04, with a 95% confidence interval of 1.70-14.98; P<0.01). It seems likely that T. canis infection is common among the children who live in slums in Swaziland, particularly in the country's middleveld, probably as the result of poor hygiene and poor sanitation.


Assuntos
Antígenos de Helmintos/imunologia , Proteínas de Helminto/imunologia , Toxocara canis/imunologia , Toxocaríase/epidemiologia , Adulto , Distribuição por Idade , Animais , Antígenos de Helmintos/isolamento & purificação , Western Blotting , Criança , Pré-Escolar , Reações Cruzadas , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Ensaio de Imunoadsorção Enzimática/métodos , Essuatíni/epidemiologia , Feminino , Proteínas de Helminto/isolamento & purificação , Humanos , Masculino , Áreas de Pobreza , Saneamento/normas , Estudos Soroepidemiológicos , Toxocaríase/imunologia , Toxocaríase/transmissão , População Urbana
11.
Curr Microbiol ; 35(1): 32-9, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9175557

RESUMO

The purification and characterization of an extracellular protease produced by pathogenic luminous Vibrio harveyi strain 820514, originally isolated from diseased tiger prawn (Penaeus monodon), was presented in this paper. The purification steps included ammonium sulfate precipitation, with columns of hydrophobic interaction chromatography and anion exchange on fast protein liquid chromatography. The protease is an alkaline cysteine protease, heat labile, inhibited by iodoacetamide, iodoacetic acid, N-ethylmaleimide, p-chloromercuribenzoate, and p-chloromercuribenzene-sulfonic acid, and showed maximal activities at pH 8 and 50 degrees C, having a molecular mass of 38 kDa as estimated by SDS-PAGE and gel filtration column. In addition, the protease was also completely inhibited by CuCl2 and HgCl2, but not or only partially inhibited by other inhibitors tested. Furthermore, 2-mercaptoethanol was the most effective reducing agent in the activation of the enzyme. The present protease is the first cysteine protease found in Vibrio species.


Assuntos
Cisteína Endopeptidases/isolamento & purificação , Vibrio/enzimologia , Inibidores de Cisteína Proteinase/farmacologia , Concentração de Íons de Hidrogênio , Peso Molecular , Temperatura
12.
Zhonghua Yi Xue Za Zhi (Taipei) ; 56(3): 192-8, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8854442

RESUMO

BACKGROUND: During the past several years, coralline hydroxyapatite ocular implant has gained increasingly wide acceptance among ophthalmologists. This ocular implant is used in eviscerated eyes to restore volume loss. Its advantages and complications are presented. METHODS: Seventy-three patients received a coralline hydroxyapatite sphere as a buried integrated ocular implant after evisceration surgery between August 1991 and May 1994. The follow-up period was from 4 to 33 months, with mean of 13.5 months. RESULTS: There have been no recognizable cases of orbital infection, implant extrusion, or implant migration. Complications have been minimal and easily managed. Motility of the socket and fornices has been excellent, and most patients have cosmetically satisfactory motility of the prosthesis. CONCLUSIONS: The hydroxyapatite implant appears to offer excellent cosmetic reconstruction without the unacceptable infection and extrusion rates seen with other implants.


Assuntos
Evisceração do Olho , Procedimentos Cirúrgicos Oftalmológicos , Próteses e Implantes , Adolescente , Adulto , Durapatita , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
13.
J Protein Chem ; 14(4): 205-15, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7662108

RESUMO

The alkaline proteases subtilisin Carlsberg and alcalase possess substantial enzymatic activity even when dissolved in ethanol. The crude enzymes were purified by gel filtration and the main fractions suspended in ethanol to give a translucent suspension. Both the supernatant and the resuspended precipitate after high-speed centrifugation were found to have enzymatic activities. The solubility of subtilisin Carlsberg in anhydrous ethanol was found to be 45.1 micrograms/ml and that of alcalase was 48.1 micrograms/ml by Coomassie blue dye-binding method using bovine serum albumin as a standard. In the presence of water, the solubility of both enzymes increased with water content. The stability of enzymes incubated in ethanol was assayed by their amidase and transesterase activities using Ala-Ala-Pro-Phe-pNA as substrate in phosphate buffer (pH8.2) and Moz-Leu-OBzl as substrate in anhydrous ethanol, respectively. The soluble enzymes have a half-life of about 36 hr and that of suspended enzymes about 50 hr in the amidase activity assay, whereas the same soluble enzymes have a half-life of about several hours and that of suspended enzymes 1 h by the transesterase activity assay. The stability of both enzymes decreased as water concentration increased. The diastereoselectivity of the enzyme-catalyzed hydrolysis of diastereo pairs of tetrapeptide esters, L-Ala-L-Ala-(D- or L-)Pro-L-Phe-OMe and L-Ala-L-Ala-(D- or L-)Ala-L-Phe-OMe, in phosphate is as high as that of the transesterification of these substrates in ethanol. It is concluded that active sites and selectivity of alkaline serine proteases in anhydrous alcohol are probably very similar to those in aqueous solution in spite of the fact that a lower reactivity is usually associated with the enzymes in nonaqueous solvents.


Assuntos
Etanol , Subtilisinas/química , Sequência de Aminoácidos , Sítios de Ligação , Fenômenos Químicos , Físico-Química , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Cinética , Dados de Sequência Molecular , Solubilidade , Subtilisinas/metabolismo , Água/metabolismo
14.
Bioorg Med Chem ; 1(5): 361-7, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8081866

RESUMO

Diastereomeric peptide-esters (Ala-Ala-AA2-Phe-OMe, AA2 = Gly, D- or L-Ala, Pro, Phe, Lys, and Glu) have been used as substrates, and the kinetic constants (Kcat and Km) of the three alkaline proteases, subtilisin Carlsberg, alcalase, and Nagarse (subtilisin BPN') catalyzed ester-hydrolysis, were measured to investigate the selectivity of the enzyme-catalyzed peptide esterhydrolysis. All three proteases preferred the substrate which had a small side-chain at the s-2 site. Thus, the substrates with a bulky side-chain at the p-2 site such as Phe, Pro, Glu, and Lys, hydrolyzed with a rate of about one-tenth that of Ala at the p-2 site, and the Kcat decreased as the size of the p-2 amino acid residue increased. The diastereoselectivity of the alkaline protease-catalyzed hydrolysis of each diastereomeric pair depended on the size of the amino acid residue at the p-2 position of the substrate. The substrates with a bulky side-chain at the p-2 site hydrolyzed with higher diastereoselectivity than did the substrates with a small side-chain at the p-2 site. Molecular modeling of the enzyme-substrate complex show that: for the enzyme complexed with a substrate which has L-L-L-L configuration, each residue of the L-L-L-L tetrapeptide filled in and was completely enclosed by the cleft of the four subsites of the enzyme. The side-chains of the residues were identically positioned within the pocket of the binding-site. For the complex of enzyme with substrate of L-L-D-L, the side-chain of the D-amino acid residue was far away from the s-2 subsite of the enzyme, and had close contact with the side-chains of Leu-126 and Ile-107 of the enzyme.


Assuntos
Oligopeptídeos/metabolismo , Subtilisinas/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Hidrólise , Técnicas In Vitro , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Oligopeptídeos/síntese química , Oligopeptídeos/química , Soluções , Estereoisomerismo , Especificidade por Substrato , Subtilisinas/química , Água
17.
J Nematol ; 3(1): 39-42, 1971 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19322338

RESUMO

Incidence and severity of root-rot caused by the fungus Macrophomina phaseoli was increased in screenhouse-grown kenaf (Hibiscus cannabinus L.) seedlings simultaneously infected by the nematode Meloidogyne javanica. In seedlings inoculated at 5, 10 and 15 days of age, root rot lesions increased 70.3, 44.1 and 21.8%, and nematode penetration increased 49.0, 36.7, and 12.3% when both fungus and nematode were present.

18.
J Bacteriol ; 93(3): 886-93, 1967 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-4381635

RESUMO

After growth on various carbon sources, sonic extracts of Hydrogenomonas facilis contained ribulosediphosphate (RuDP) carboxylase and phosphoribulokinase (Ru5-P kinase). After very short sonic treatment, a reductive adenosine triphosphate (ATP)-dependent incorporation of (14)CO(2) was also detectable. Reduced nicotinamide adenine dinucleotide (NADH(2)) served as reductant 30-fold more effectively than reduced nicotinamide adenine dinucleotide phosphate (NADPH(2)). Adenosine 5'-phosphate (AMP) and adenosine 5'-pyrophosphate (ADP) inhibited Ru5-P kinase and NADH(2)-, ATP-dependent CO(2) fixation. The levels and duration of CO(2) fixation suggested that it is a cyclic process. The requirement of reduced pyridine nucleotide and ATP and the sensitivity of fixation to AMP and ADP support the conjecture that it occurs via the Calvin cycle. After thorough study of variables affecting catalysis, specific activities (millimicromoles of substrate disappearing per milligram of protein) at 30 C were determined for RuDP carboxylase (C), Ru5-P kinase (K) and ATP-, NADH(2)- dependent CO(2) fixation (CO(2) F) after growth autotrophically on fructose, glucose, ribose, glutamate, lactate, succinate, and acetate. Values for these growth modes were, respectively-for C: 67.3, 51.1, 51.4, 24.6, 2.05, 10.2, 2.25, 1.4; for K: 24.7, 24.0, 23.2, 14.2, 12.8, 12.9, 13.4, 2.8; and for CO(2) F: 4.54, 4.83, 3.10, 2.87, 0.85, 1.51, 0.24, 0.41. The qualitative parallel between values for RuDP carboxylase and CO(2) fixation suggests that one major control point in fixation is the step catalyzed by RuDP carboxylase.


Assuntos
Carboxiliases/metabolismo , Fosfotransferases/metabolismo , Pseudomonas/enzimologia , Pseudomonas/metabolismo , Nucleotídeos de Adenina/farmacologia , Autorradiografia , Bicarbonatos/farmacologia , Dióxido de Carbono/metabolismo , Isótopos de Carbono , Cromatografia em Papel , Magnésio/farmacologia , NAD/farmacologia , NADP/farmacologia
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