Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Microb Biotechnol ; 17(6): e14486, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38858805

RESUMEN

Social habits and economies driven by profit are opposing efforts to reach a path of sustainable development. In addition, many communities worldwide have diverged away from nature through consumerism and technology. In the context of the escalating risks and consequences related to global challenges such as the climate crisis and ecosystem degradation, education for sustainable development and science-driven decision-making offer tremendous opportunities for improvement.


Asunto(s)
Desarrollo Sostenible , Humanos , Cambio Climático , Educación , Conservación de los Recursos Naturales
3.
Microb Biotechnol ; 10(5): 1066-1069, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28696041

RESUMEN

Complex communities of microbes live on and in plants, humans and other animals. These communities are collectively referred to as the microbiota or microbiome. Plants and animals evolved to co-exist with these microbes. In mammals, particular kinds of alteration of the microbiome (dysbiosis) are associated with loss of health, most likely due to loss of microbial metabolites, signalling molecules, or regulators of host pathways. Modern life-style diseases such as Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), type 2 diabetes, obesity and metabolic syndrome have been linked to dysbiosis. These multifactorial diseases involve multiple risk factors and triggers, depletion of certain gut microbiota species being one of them. Live Biotherapeutics operate by restoring microbial products or activities in affected subjects. They are being developed as adjuncts, alternatives or new treatment options for diseases that affect a growing proportion of global citizens.


Asunto(s)
Diabetes Mellitus Tipo 2/microbiología , Disbiosis/microbiología , Microbioma Gastrointestinal , Enfermedades Inflamatorias del Intestino/microbiología , Síndrome del Colon Irritable/microbiología , Animales , Terapia Biológica , Diabetes Mellitus Tipo 2/terapia , Disbiosis/terapia , Humanos , Enfermedades Inflamatorias del Intestino/terapia , Síndrome del Colon Irritable/terapia
4.
J Res Med Sci ; 18(8): 668-73, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24379842

RESUMEN

BACKGROUND: Metabolic syndrome (MetS) is a serious public health problem. It is an important risk factor of cardiovascular disease in developed countries. Adipose tissue considered as an organ that releases a variety of molecules referred to adipocytokines such as leptin. Polymorphism of their related genes may play an important role in development of MetS. The aim of this study was to determine the association of leptin gene-2548G/A (LEP-2548G/A) polymorphism with lipid profile in subjects with and without Mets. MATERIALS AND METHODS: In this case/control study a frequency of LEP-2548G/A single nucleotide polymorphism was determined between 200 patients (142 women and 58 men) and 200 controls (122 women and 78 men). Both groups were selected randomly from Hamadan city, Iran. Blood samples were collected then followed by routine biochemical analysis, DNA extraction and serum leptin measurements. Polymerase chain reaction-restriction fragment length polymorphism was applied to identify LEP-2548G/A genotypes. Statistical analyses were applied using SPSS software version 10. Continuous variables were presented as means± SD and compared by independent sample t-test. Variables without normal distribution compared through Mann-Whitney U test. RESULTS: In both groups, a significant difference was observed between biochemical factors and leptin concentration. Serum leptin concentration was more in females than males. No statistical significant difference was detected in the frequency of LEP-2548G/A polymorphism between both MetS and healthy groups. CONCLUSION: In summary, it is concluded that frequency of LEP G-2548A polymorphism in Metabolic syndrome (MetS) and healthy subjects was not significantly different and more research with large sample size is needed in this area.

5.
Mol Microbiol ; 75(3): 623-36, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19627502

RESUMEN

Interaction of the TolB box of Group A colicins with the TolB protein in the periplasm of Escherichia coli cells promotes transport of the cytotoxic domain of the colicin across the cell envelope. The crystal structure of a complex between a 107-residue peptide (TA(1-107)) of the translocation domain of colicin A (ColA) and TolB identified the TolB box as a 12-residue peptide that folded into a distorted hairpin within a central canyon of the beta-propeller domain of TolB. Comparison of this structure with that of the colicin E9 (ColE9) TolB box-TolB complex, together with site-directed mutagenesis of the ColA TolB box residues, revealed important differences in the interaction of the two TolB boxes with an overlapping binding site on TolB. Substitution of the TolB box residues of ColA with those of ColE9 conferred the ability to competitively recruit TolB from Pal but reduced the biological activity of the mutant ColA. This datum explains (i) the difference in binding affinities of ColA and ColE9 with TolB, and (ii) the inability of ColA, unlike ColE9, to competitively recruit TolB from Pal, allowing an understanding of how these two colicins interact in a different way with a common translocation portal in E. coli cells.


Asunto(s)
Colicinas/química , Proteínas de Escherichia coli/química , Proteínas Periplasmáticas/química , Secuencia de Aminoácidos , Sitios de Unión , Colicinas/genética , Colicinas/metabolismo , Cristalografía por Rayos X , Proteínas de Escherichia coli/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Proteínas Periplasmáticas/metabolismo , Transporte de Proteínas
6.
Indian J Med Res ; 129(3): 293-8, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19491422

RESUMEN

BACKGROUND & OBJECTIVE: Cholesteryl ester transfer protein (CETP) gene polymorphism is known to be associated with changes in lipid profiles. Primary hyperlipidaemia is considered to be a major risk factor for pancreatitis, atherosclerosis and coronary heart disease. We investigated the association of one common polymorphism in the CETP gene (Taq1B) with plasma lipid levels and CETP activity in Iranian subjects with and without primary combined hyperlipidaemia. METHODS: The study included 102 patients with primary combined hyperlipidaemia and 214 health individuals. Polymerase chain reaction and restriction fragment length polymorphisms were used for genotype detection. To determine the relationship between Taq1B polymorphism and lipid levels, lipids and CETP activity were measured in primary combined hyperlipidaemic and normolipidaemic subjects, with and without Taq1B polymorphism. RESULTS: Plasma CETP activity was significantly (P<0.001) higher in primary combined hyperlipidaemic individuals than in controls. Plasma HDL-C was higher in both groups, in the B(2)B(2) genotype than in the B(1)B(1) and B(1)B(2) genotypes, whereas the serum TG concentrations and CETP activity were lower in B(2)B(2) genotype compared with other genotypes (B(1)B(1) and B(1)B(2)). The genotype and allelic frequencies for this polymorphism differed significantly between hyperlipidaemic and nonmolipidaemic individuals (P<0.05). In both groups, CETP Taq 1B polymorphism (presence of B(2) allele) correlated significantly with HDL-cholesterol (HDL-C) (r=0.201 and r=0.452 in control and patient groups respectively) and CETP activity (r= -0.123 for controls and r= -0.192 for patients). INTERPRETATION & CONCLUSION: The results showed that Taq 1B polymorphism of CETP gene was associated with changes in lipids profile and plasma CETP activity in the selected population and might have a role in contributing to genetic risk of developing coronary artery disease.


Asunto(s)
Proteínas de Transferencia de Ésteres de Colesterol/genética , Hiperlipidemia Familiar Combinada/epidemiología , Hiperlipidemia Familiar Combinada/genética , Polimorfismo Genético , Adulto , Enfermedad de la Arteria Coronaria/sangre , Enfermedad de la Arteria Coronaria/epidemiología , Enfermedad de la Arteria Coronaria/genética , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad/epidemiología , Genotipo , Humanos , Hiperlipidemia Familiar Combinada/sangre , Irán/epidemiología , Lípidos/sangre , Masculino , Persona de Mediana Edad , Factores de Riesgo
7.
J Mol Biol ; 386(3): 754-72, 2009 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-19152799

RESUMEN

The crystal structure of an active form of ScpA has been solved to 1.9 A resolution. ScpA is a multidomain cell-envelope subtilase from Streptococcus pyogenes that cleaves complement component C5a. The catalytic triad of ScpA is geometrically consistent with other subtilases, clearly demonstrating that the additional activation mechanism proposed for the Streptococcus agalactiae homologue (ScpB) is not required for ScpA. The ScpA structure revealed that access to the catalytic site is restricted by variable regions in the catalytic domain (vr7, vr9, and vr11) and by the presence of the inserted protease-associated (PA) domain and the second fibronectin type III domains (Fn2). Modeling of the ScpA-C5a complex indicates that the substrate binds with carboxyl-terminal residues (65-74) extended through the active site and core residues (1-64) forming exosite-type interactions with the Fn2 domain. This is reminiscent of the two-site mechanism proposed for C5a binding to its receptor. In the nonprime region of the active site, interactions with the substrate backbone are predicted to be more similar to those observed in kexins, involving a single beta-strand in the peptidase. However, in contrast to kexins, there would be diminished emphasis on side-chain interactions, with little charged character in the S3-S1 and S6-S4 subsites occupied by the side chains of residues in vr7 and vr9. Substrate binding is anticipated to be dominated by ionic interactions in two distinct regions of ScpA. On the prime side of the active site, salt bridges are predicted between P1', P2', and P7' residues, and residues in the catalytic and PA domains. Remote to the active site, a larger number of ionic interactions between residues in the C5a core and the Fn2 domain are observed in the model. Thus, both PA and Fn2 domains are expected to play significant roles in substrate recognition.


Asunto(s)
Adhesinas Bacterianas/química , Endopeptidasas/química , Adhesinas Bacterianas/metabolismo , Secuencia de Aminoácidos , Dominio Catalítico , Complemento C5a/química , Complemento C5a/metabolismo , Cristalografía por Rayos X , Endopeptidasas/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , Alineación de Secuencia , Streptococcus pyogenes/química
8.
Proteins ; 70(2): 378-87, 2008 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-17680689

RESUMEN

The beta-propeller fold is a phylogenetically widespread, common protein architecture able to support a range of different functions such as catalysis, ligand binding and transport, regulation and protein binding. Interestingly, it appears that the beta-propeller topology is also compatible with strikingly diverse sequences. Amongst this diversity, there are three large groups of proteins with related sequences and very important cellular and intercellular regulatory functions: WD, kelch, and YWTD proteins. A common characteristic between these protein families is that their sequences, while distinct, all contain internal repeats 40-45 residues long. Through a pangenomic analysis using internal repeat profiles derived from the structurally known propeller modules of the eukaryotic protein RCC1 and the related prokaryotic protein BLIP-II, we have defined a new superfamily of propeller repeats, the RCC1-like repeats (RLRs). These sequences turn out to be more phylogenetically widespread than other large groups of propeller proteins, occurring in both prokaryotic and eukaryotic genomes. Interestingly, our research showed that RLR domains with different numbers of repeats exist, ranging from 3 to 7, and possibly more. A novel, intriguing finding is the discovery of sequences with 3 repeats, as well as proteins with 10 modular units, though in the latter case it is not clear whether these are made of two 5-bladed domains or a single, novel 10-bladed propeller. In addition, the results indicate that circular permutation events may have taken place in the evolution of these proteins. It is now established that the group of RLR proteins is extremely numerous and is characterized by unique, remarkable features which place it in a position of special interest as an important superfamily of proteins in nature.


Asunto(s)
Proteínas de Ciclo Celular/química , Genoma , Factores de Intercambio de Guanina Nucleótido/química , Proteínas Nucleares/química , Secuencia de Aminoácidos , Proteínas de Ciclo Celular/genética , Factores de Intercambio de Guanina Nucleótido/genética , Datos de Secuencia Molecular , Proteínas Nucleares/genética , Conformación Proteica , Homología de Secuencia de Aminoácido
9.
Artículo en Inglés | MEDLINE | ID: mdl-17768344

RESUMEN

CB1954 is an anticancer prodrug that is currently in clinical trials coupled with the Escherichia coli flavoenzyme nitroreductase (NTR) for use in directed-enzyme prodrug therapy (DEPT). The NTR enzyme is responsible for the conversion of the prodrug into a cytotoxic agent. The bifunctional alkylating agent produced by this bioactivation process leads to DNA damage and death of cancer cells. Recently, a novel flavoenzyme from Bacillus amyloliquefaciens, YwrO (Bam YwrO), was reported to be able to reduce CB1954 from its noncytotoxic form into its active form. The crystallization and preliminary X-ray diffraction analysis of two crystal forms of Bam YwrO are reported. The first crystal form is orthorhombic, with space group P22(1)2(1), and diffracts X-rays to 2.18 A resolution. The second crystal form is tetragonal, with space group P4(1), and diffracts X-rays to 3.4 A. Determination of the Bam YwrO crystal structure will provide an understanding of the molecular recognition between this enzyme and the anticancer prodrug CB1954.


Asunto(s)
Bacillus/enzimología , Proteínas Bacterianas/química , Nitrorreductasas/química , Secuencia de Aminoácidos , Proteínas Bacterianas/aislamiento & purificación , Secuencia de Bases , Clonación Molecular , Cristalización , Cartilla de ADN , Datos de Secuencia Molecular , Nitrorreductasas/aislamiento & purificación , Fragmentos de Péptidos/química , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Difracción de Rayos X
11.
J Biol Chem ; 282(14): 10625-31, 2007 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-17287214

RESUMEN

Pathogens such as Staphylococcus aureus require iron to survive and have evolved specialized proteins to steal heme from their host. IsdC is the central conduit of the Isd (iron-regulated surface determinant) multicomponent heme uptake machinery; staphylococcal cell-surface proteins such as IsdA, IsdB, and IsdH are thought to funnel their molecular cargo to IsdC, which then mediates the transfer of the iron-containing nutrient to the membrane translocation system IsdDEF. The structure of the heme-IsdC complex reveals a novel heme site within an immunoglobulin-like domain and sheds light on its binding mechanism. The folding topology is reminiscent of the architecture of cytochrome f, cellobiose dehydrogenase, and ethylbenzene dehydrogenase; in these three proteins, the heme is bound in an equivalent position, but interestingly, IsdC features a distinct binding pocket with the ligand located next to the hydrophobic core of the beta-sandwich. The iron is coordinated with a tyrosine surrounded by several non-polar side chains that cluster into a tightly packed proximal side. On the other hand, the distal side is relatively exposed with a short helical peptide segment that acts as a lip clasping onto almost half of the porphyrin plane. This structural feature is argued to play a role in the mechanism of binding and release by switching to an open conformation and thus loosening the interactions holding the heme. The structure of the heme-IsdC complex provides a template for the understanding of other proteins, such as IsdA, IsdB, and IsdH, that contain the same heme-binding module as IsdC, known as the NEAT (near transporter) domain.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Portadoras/química , Hemo/química , Hierro/química , Staphylococcus aureus/química , Proteínas Bacterianas/metabolismo , Sitios de Unión , Proteínas Portadoras/metabolismo , Hemo/metabolismo , Hierro/metabolismo , Oxidorreductasas/química , Oxidorreductasas/metabolismo , Unión Proteica , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Staphylococcus aureus/metabolismo , Homología Estructural de Proteína
12.
Artículo en Inglés | MEDLINE | ID: mdl-17277452

RESUMEN

The DnaD protein is an essential component of the chromosome-replication machinery of the Gram-positive bacterium Bacillus subtilis and is part of the primosomal cascade that ultimately loads the replicative ring helicase DnaC onto DNA. Moreover, DnaD is a global regulator of DNA architecture, as it forms higher order nucleoprotein structures in order to open supercoiled DNA. Here, the crystallization and preliminary X-ray diffraction analysis of the two domains of DnaD from B. subtilis are reported. Crystals of the N-terminal domain are trigonal, with either P3(1)21 or P3(2)21 space-group symmetry, and diffracted X-rays to 2.0 A resolution; crystals of the C-terminal domain are hexagonal, with space group P6(1) or P6(5), and diffracted X-rays to 2.9 A resolution in-house. Determination of the structure of the DnaD domains will provide insight into how remodelling of the nucleoid is associated with priming of replication in the model Gram-positive organism B. subtilis.


Asunto(s)
Bacillus subtilis/química , Proteínas Bacterianas/química , Proteínas de Unión al ADN/química , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Clonación Molecular , Cristalización , Cristalografía por Rayos X , Proteínas de Unión al ADN/genética , Escherichia coli/genética , Escherichia coli/metabolismo
13.
Pak J Biol Sci ; 10(23): 4224-9, 2007 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-19086575

RESUMEN

Primary hypertriglyceridemia is considered to be a major risk factor for pancreatitis, atherosclerosis and coronary heart disease. Cholesteryl ester transfer protein gene polymorphisms known to be associated with changes in lipid levels. This study was performed by using polymerase chain reaction and restriction fragment length polymorphisms. Genotype distribution and allelic frequencies of polymorphism were determined and compared in primary hypertriglyceridemic and normotriglyceridemic subjects. The results showed that plasma cholesteryl ester transfer protein activity was significantly higher in primary hypertriglyceridemia than in controls (p = 0.001). In this study all individuals with B2B2 genotype had lower plasma cholesteryl ester transfer protein activity, higher high-density lipoprotein than B1B1 and B1B2 genotypes, whereas triglyceride was significantly decreased in this genotype. The genotype and allelic frequencies for this polymorphism differed significantly between primary hypertriglyceridemic patients and controls (p = 0.014 and p = 0.027, respectively). In both groups, CETP Taq 1B polymorphism (presence of B2 allele) correlated significantly with HDL-C (r = 0.207 and 0.300 in control and patient groups, respectively) and CETP activity (r = -0.193 for controls and r = -0.132 for patients). Taq 1B polymorphism of cholesteryl ester transfer protein gene was associated with changes in lipids profile and plasma cholesteryl ester transfer protein activity in the selected population.


Asunto(s)
Proteínas de Transferencia de Ésteres de Colesterol/genética , Hipertrigliceridemia/genética , Polimorfismo Genético , Secuencia de Bases , Estudios de Casos y Controles , Cartilla de ADN , Humanos , Irán , Reacción en Cadena de la Polimerasa
14.
J Biol Chem ; 281(43): 32606-10, 2006 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-16943192

RESUMEN

Bacteria rely on their environment and/or host to acquire iron and have evolved specialized systems to sequester and transport heme. The heme uptake system HemRSTUV is common to proteobacteria, and a major challenge is to understand the molecular mechanism of heme binding and transfer between the protein molecules that underlie this heme transport relay process. In the Gram-negative pathogen Yersinia enterocolitica, the HemRSTUV system culminates with the cytoplasmic recipient HemS, which stores and delivers heme for cellular needs. HemS belongs to a family of proteins essential and unique to proteobacteria. Here we report on the binding mechanism of HemS based on structural data from its apo- and ligand-loaded forms. This heme carrier protein associates with its cargo through a novel, partly preformed binding pocket, formed between a large beta-sheet dome and a three-helix subdomain. In addition to a histidine interacting with the iron, the complex is stabilized by a distal non-coordinating arginine that packs along the porphyrin plane and extensive electrostatic contacts that firmly anchor the heme propionate groups within the protein. Comparison of apo- and ligand-bound HemS crystal structures reveals striking conformational changes that underlie a "heme-induced fit" binding mechanism. Local shifts in amino acid positions combine with global, rigid body-like domain movements, and together, these bring about a switch from an open, apo-form to a closed, bound state. This is the first report in which both liganded and unliganded forms of a heme transport protein are described, thus providing penetrating insights into its mechanism of heme binding and release.


Asunto(s)
Hemoproteínas/química , Hemoproteínas/metabolismo , Conformación Proteica , Proteobacteria/química , Transporte Biológico , Hemoproteínas/aislamiento & purificación , Histidina/química , Histidina/metabolismo , Modelos Moleculares , Electricidad Estática
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...