Inhibitory effect of lotus seedpod oligomeric procyanidins on advanced glycation end product formation in a lactose-lysine model system

Background Industrial food processing induces protein glycation modifications and toxic advanced glycation end products (AGEs) which affect human health. Therefore, it is of interest to monitor AGEs in food processing. The present study was carried out to investigate the influence of lotus seedpod oligomeric procyanidin (LSOPC) concentrations, solution pH value and metal ions on AGE formation by heat treatment of lactose-lysine model solutions. Ne-(carboxymethyl) lysine (CML), as one of the common AGEs was also determined by HPLC-MS/MS in this experiment. Results The results showed that LSOPC can inhibit the formation of AGEs effectively at higher concentrations, lower temperature, and it can reverse the promotion function of metal ions because of its high inhibition activity. Also, LSOPC can inhibit CML formation in the Maillard reaction as well. Conclusion These results indicated that LSOPC could be used as functional food ingredients to inhibit AGE formation.

Suicide attempts among children and adolescents: partial or total injury? / Tentativa de suicídio infanto-juvenil: lesão da parte ou do todo?

This study sought to verify the records on file and the number of cases of attempted suicide among children and adolescents who were attended by Emergency Care health professionals in the municipality of Matozinhos, Minas Gerais, Brazil. Documentary and descriptive research was conducted, the data for which was collected by means of an investigation of Outpatient Records from 2008 to 2010. Of the 73,000 files evaluated, those dealing with cases of attempted suicide among children and adolescents between the age of 3 and 18 years were selected. It was revealed that the health professionals, particularly physicians and nurses, fail to register the cases appropriately, invalidating information about the problem and potential prevention measures. The conclusion reached was that underreporting and the discrepancy of the diagnoses which were not duly referred to the competent agencies require rethinking and reviewing medical practices, and taking a systematic and careful look to address the individual as a complex whole.

Neste estudo procurou-se verificar o registro e o número de casos de tentativa de suicídio entre crianças e adolescentes do município de Matozinhos, Minas Gerais, Brasil, que foram atendidos pelos profissionais de saúde do Pronto-Atendimento. Trata-se de uma pesquisa documental e descritiva, cuja coleta dos dados ocorreu por meio de investigação nas Fichas Ambulatoriais, no período de 2008 a 2010. Das 73.000 fichas levantadas, selecionaram-se aquelas que tratavam de casos de tentativa de suicídio entre crianças e adolescentes do município, com idades entre três e 18 anos. Percebeu-se que os profissionais de saúde, mais especificamente os médicos e enfermeiros, não registram os casos de forma adequada, inviabilizando a informação sobre o problema e as medidas de prevenção. Concluiu-se que a subnotificação, a discrepância dos diagnósticos e o não encaminhamento aos órgãos competentes exigem repensar e rever a prática médica e dirigir um olhar sistematizado e cuidadoso para perceber o sujeito como um todo complexo.

Lys-413 of S-phase mRNA cycling sequence binding protein from Leishmania donovani (LdCSBP) is modified through monoubiquitination that is responsible for inhibition of its riboendonuclease activity.

In addition to well-known process of proteasome-mediated degradation of polyubiquitinated proteins, monoubiquitination of proteins is also an important post-translational modification that regulates various non-degradative cellular processes like protein trafficking, cellular signalling, DNA replication and DNA repair. We have previously characterized a multi-domain cycling sequence binding protein LdCSBP from Leishmania donovani, which binds specifically to a conserved CAUAGAAG octamer containing RNAs via its uniquely arranged CCCH type Zn-fingers and degrades them using its Smr endonuclease domain, indicative of its potential role in the turnover of the S-phase mRNAs. Remarkably, its riboendonuclease activity is inhibited due to the incorporation of a monoubiquitin residue in the ZnF domain, though the target Lys residue remains unknown. Here, we report through systematic mutation of Lys residue to Ala that Lys-413 in LdCSBP is the site of monoubiquitination. However, the amino acid motif around the target Lys in LdCSBP is not consensus with any previously known monoubiquitination site, though partial homology is observed with a subset of recently identified mammalian ubiquitination target sites. Interestingly, Lys-413 of LdCSBP is conserved in the homologous annotated proteins from the related kinetoplastida parasites, suggesting similar monoubiquitination-mediated regulation of RNA endonuclease activity in the organisms.

Contribution of Ser463 residue to the enzymatic and autoprocessing activities of Escherichia coli -glutamyltranspeptidase.

A serine residue Ser463, required for proper function of E. coli -glutamyltranspeptidase (EcGGT) was identified by site-directed mutagenesis on the basis of sequence alignment of human, pig, rat, and three bacterial enzymes. Thr-, Asp-, and Lys-substituted variants were overexpressed in E. coli M15 cells and the recombinant proteins were purified to near homogeneity by nickel-chelate chromatography. With the exception of S463T, the other two variants completely lost GGT activity, implying the importance of this residue in EcGGT. Moreover, substitution of Ser463 with either Lys or Asp impaired the capability of autocatalytic processing of the precursor into - and -subunit. Computer modeling showed that the critical bonding distance of Gln390 C-Thr391 OG1 was significantly increased in S463D and S463K, indicating that these distance changes might be responsible for the lack of enzyme maturation. Measurements of intrinsic tryptophan fluorescence revealed alteration of the microenvironment of aromatic amino acid residues in S463D and S463K, while circular dichroism (CD) spectra were nearly identical for wild-type and all mutant enzymes. The temperature-dependent signal in the far-UV region for S463T was consistent with that of wild-type enzyme, but S463D and S463K showed a different sensitivity towards temperature-induced denaturation. These results implied that a significant conformational change occurred as a result of Asp- and Lys-substitution.

Molecular characterization of hair cuticle and its extracted proteins in seven mammalian species

Hair is an of the epidermis in mammals and consists of two large groups of human hair proteins. One is hard -keratins and the other is matrix proteins. The present investigation aimed to compare the ultrastructural of the hair scale using the scanning electron microscope, and the proteins and amino acids content of the keratin in seven mammalian species. The values of the hair thickness, x/y feret and hair pattern of the species in the present study confirm the presence of species-specific characteristics and ultra structural variation. The situation in man differs from the wild mammals due to damage of hair cuticle caused by mechanical abuse, exposure to ultraviolet radiation and chemical over processing. The maximum amount of extracted proteins from hair keratin was analyzed by SDS-PAGE. The electrophoretic patterns showed an overall degree of similarity. However, differences exist between species in the intensity of stain. Quantitatively, the electrophoretic patterns scanned and analyzed using gel protein analyzer. The results showed no difference between the molecular mass of some species, but different in molecular mass distribution. Amino acid composition of keratin of mammalian hair species of the present study showed some variation, especially for methionine, isoleucine, lysine and arginine. The other amino acids studied are significantly present in most hair. One of the later amino acid is cysteine. Cysteine is a very important due to the presence of disulfate cross-links

Role of positive charge of lysine residue on ribosome-inactivating property of gelonin.

The report that gelonin cross-linked with monoclonal antibodies with the use of 2-iminothiolane (2-IT) exhibited higher cytotoxicity than the conjugates prepared with the use of N-succinimidyl-3-(2-pyridylthio) propionate (SPDP) alone, has prompted us to investigate the effect of epsilon-NH2 group modification with 2-IT on the ribosome-inactivating property (RIP) of gelonin. The purified gelonin was modified with 2-IT at a different molar ratio and their effects on immunoreactivity and ribosome-inactivating property were compared with those of N-succinimidyl 6-[3-(2-pyridyldithio) propionamido] hexanoate (long chain-SPDP) and SPDP modified gelonin derivatives. Modification of single amino group with 2-IT results in about 25-50% inhibition of immunoreactivity and 60-70% loss of protein synthesis inhibition activity. Modification of 2-3 amino groups further hampers both immunoreactivity and protein synthesis inhibition property of gelonin. Both the long chain-SPDP with SPDP modifications showed more pronounced effects on immunoreactivity and RIP activity as compared to the similar ratio of 2-IT modification(s). It may, therefore, be concluded that the positive charge plays an important role in the immunological as well as the protein synthesis inhibitory effect of gelonin.

Characterization and biological activities of Chenopodium leaf hemagglutinin (CLH).

A hemagglutinin (CLH) having native molecular mass of 58 kDa and subunit molecular mass of 33 kDa had been purified from the leaves of Chenopodium amaranticolor. The protein agglutinated rabbit erythrocytes and no agglutination was observed with any of the groups A, B or O of human blood. The amino acid composition revealed that CLH was rich in aspartic acid, glutamic acid, glycine and phenylalanine and also significant amount of methionine. The N-terminal amino acid sequence analysis showed that CLH had no homology with any of the plant hemagglutinins studied so far. It was inactive towards human peripheral blood cells but mitogenic for mouse spleen B-lymphocytes. CLH inhibited protein synthesis in rat thymocytes at high concentration. CLH did not inhibit TMV infection of leaves indicating absence of antiviral properties.

Significance of charge on lysine residue of ovine luteinizing hormone on immunological and biological properties of the hormone.

In order to understand the significance of positive charge of lysine residues of ovine luteinizing hormone (oLH) on immunological and biological activity, the epsilon-NH2 group(s) of ovine LH were sequentially modified with 2-iminothiolane (2IT) that preserves the positive charge of the lysine while the overall charge of the hormone remains unchanged. These studies have also been compared with the oLH modified by N-succinimidyl 3-(2 pyridyldithio) propionate (SPDP) and succinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate (LC-SPDP) that abolish positive charge of lysine residues. The modification primarily occurs in the alpha-subunit. Sequential modification led to progressive reduction in receptor binding and immunological activities. However, the steroidogenic activity was substantially retained. The immunoreactivity and receptor binding properties of 2IT modified oLH (oLH-2IT) were less affected when compared to SPDP (oLH-SPDP) or LC-SPDP (oLH-LC-SPDP) modified derivatives suggesting that increase in hydrophobic carbon chain in oLH-LC-SPDP molecule resulted in drastic inhibition in immunological and biological properties. But the steroidogenic potential of oLH-2IT, oLH-LC-SPDP or oLH-SPDP was relatively comparable. This suggests that a single -NH2 group modification with 2IT would generate the site in the hormone for conjugation to the toxin/carrier proteins that may retain better immunological and biological activity compared to that of SPDP or LC-SPDP modified oLH.