The congenital cataract-causing mutations P20R and A171T are associated with important changes in the amyloidogenic feature,structure and chaperone-like activity of human αB-crystallin

Cataract is the major reason for human blindness worldwide. α-Crystallin, as a key chaperone of eye lenses, keeps the lenticular tissues in its transparent state over time. In this study, cataract-causing familial mutations, P20R and A171T, were introduced in CRYАB gene. After successful expression in Escherichia coli and subsequent purification, the recombinant proteins were subjected to extensive structural and functional analyses using various spectroscopic techniques, gel electrophoresis, and electron microscopy. The results of fluorescence and Raman assessments suggest important but discreet conformational changes in human αB-Cry upon these cataractogenic mutations. Furthermore, the mutant proteins exhibited significant secondary structural alteration as revealed by FTIR and Raman spectroscopy. An increase in conformational stability was seen in the human αB-Cry bearing these congenital cataractogenic mutations. The oligomeric size distribution and chaperone-like activity of human αB-Cry were significantly altered by these mutations. The P20R mutant protein was observed to loose most of the chaperone-like activity. Finally, these cataractogenic mutant proteins exhibited an increased propensity to form the amyloid fibrils when incubated under environmental stress. Overall, the structural and functional changes in mutated human αB-Cry proteins can shed light on the pathogenic development of congenital cataracts.     

Identifying Extrinsic versus Intrinsic Drivers of Variation in Cell Behavior in Human iPSC Lines from Healthy Donors

1. Download high-res image (169KB)
2. Download full-size image

     

Do ACE and CKMM gene variations have potent effects on physical performance in inactive male adolescents?

Molecular Biology Reports - We studied to ascertain whether the ACE and/or CKMM genotypes independently influence the baseline level of some sport performances in 613 inactive male adolescents...     

Coronary and cardiovascular risk estimation for primary prevention: validation of a new Sheffield table in the 1995 Scottish health survey population

ObjectiveTo examine the accuracy of a new version of the Sheffield table designed to aid decisions on lipids screening and detect thresholds for risk of coronary heart disease needed to implement current guidelines for primary prevention of cardiovascular disease.DesignComparison of decisions made on the basis of the table with absolute risk of coronary heart disease or cardiovascular disease calculated by the Framingham risk function. The decisions related to statin treatment when coronary risk is ⩾30% over 10 years; aspirin treatment when the risk is ⩾15% over 10 years; and the treatment of mild hypertension when the cardiovascular risk is ⩾20% over 10 years.SettingThe table is designed for use in general practice.SubjectsRandom sample of 1000 people aged 35-64 years from the 1995 Scottish health survey.Results13% of people had a coronary risk of ⩾15%, and 2.2% a risk of ⩾30%, over 10 years. 22% had mild hypertension (systolic blood pressure 140-159 mm Hg). The table indicated lipids screening for everyone with a coronary risk of ⩾15% over 10 years, for 95% of people with a ratio of total cholesterol to high density lipoprotein cholesterol of ⩾8.0, but for <50% with a coronary risk of <5% over 10 years. Sensitivity and specificity were 97% and 95% respectively for a coronary risk of ⩾15% over 10 years; 82% and 99% for a coronary risk of ⩾30% over 10 years; and 88% and 90% for a cardiovascular risk of ⩾20% over 10 years in mild hypertension.ConclusionThe table identifies all high risk people for lipids screening, reduces screening of low risk people by more than half, and ensures that treatments are prescribed appropriately to those at high risk, while avoiding inappropriate treatment of people at low risk.     

Relationship between the Structure and Chaperone Activity of Human αA-Crystallin after Its Modification with Diabetes-Associated Oxidative Agents and Protective Role of Antioxidant Compounds

Biochemistry (Moscow) - The study was aimed to evaluate the impact of peroxynitrite (PON, oxidative stress agent in diabetes), methylglyoxal (MGO, diabetes-associated reactive carbonyl compound),...     

Advanced glycation end products enhance expression of pro-apoptotic genes and stimulate fibroblast apoptosis through cytoplasmic and mitochondrial pathways

Both aging and diabetes are characterized by the formation of advanced glycation end products (AGEs). Both exhibit other similarities including deficits in wound healing that are associated with higher rates of fibroblast apoptosis. In order to investigate a potential mechanism for enhanced fibroblast apoptosis in diabetes and aged individuals, experiments were carried out to determine whether the predominant advanced glycation end product in skin, N-epsilon-(carboxymethyl) lysine (CML)-collagen, could induce fibroblast apoptosis. In vivo experiments established that CML-collagen but not unmodified collagen induced fibroblast apoptosis and that apoptosis was dependent upon caspase-3, -8, and -9 activity. In vitro experiments demonstrated that CML-collagen but not control collagen induced a time- and dose-dependent increase in fibroblast apoptosis. By use of blocking antibodies, apoptosis was shown to be mediated through receptor for AGE signaling. AGE-induced apoptosis was largely dependent on the effector caspase, caspase-3, which was activated through both cytoplasmic (caspase-8-dependent) and mitochondrial (caspase-9) pathways. CML-collagen had a global effect of enhancing mRNA levels of pro-apoptotic genes that included several classes of molecules including ligands, receptors, adaptor molecules, mitochondrial proteins, and others. However, the pattern of expression was not identical to the pattern of apoptotic genes induced by tumor necrosis factor alpha.     

Live and heat-inactivated lactobacilli from feces inhibit <Emphasis Type="Italic">Salmonella typhi</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis> adherence to caco-2 cells

A quantitative approach has been proposed to evaluate the competitive inhibition of Escherichia coli and Salmonella typhi by live and heat-inactivated laboratory isolated Lactobacillus sp. on adhesion to monolayer of Caco-2 cells. Three species of Lactobacillus (L. casei, L. acidophilus, L. agilis) isolated from human neonate feces and two commercial probiotic strains (L. casei, L. acidophilus) have been compared for probiotic activity. All lactobacilli were able to attach to the Caco-2 cells, however, the degree of adhesion was bacterial strain-dependent. The adhesion indices of the two commercial probiotic strains were not significantly different from the values obtained for the other two similar fecal strains (p > 0.01). The inhibition of attachment of the pathogenic bacteria by inactivated cells of fecal L. acidophilus was examined and compared to the results of live bacteria. The inhibition pattern was similar for live and heat-inactivated L. acidophilus (p > 0.01). The number of attached pathogenic bacteria to the Caco-2 cells decreased when the number of L. acidophilus increased from 10⁶ to 10⁹ CFU/mL. The heat-inactivated L. acidophilus displayed similar probiotic activity compared to the live bacteria.