Dynamic evolution of selenocysteine utilization in bacteria: a balance between selenoprotein loss and evolution of selenocysteine from redox active cysteine residues.

Background: Selenocysteine (Sec) is co-translationally inserted into protein in response to UGA codons. It occurs in oxidoreductase active sites and often is catalytically superior to cysteine (Cys). However, Sec is used very selectively in proteins and organisms.

Selenium metabolism in Trypanosoma: characterization of selenoproteomes and identification of a Kinetoplastida-specific selenoprotein.

Proteins containing the 21st amino acid selenocysteine (Sec) are present in the three domains of life. However, within lower eukaryotes, particularly parasitic protists, the dependence on the trace element selenium is variable as many organisms lost the ability to utilize Sec. Herein, we analyzed the genomes of Trypanosoma and Leishmania for the presence of genes coding for Sec-containing proteins.

A relevant enzyme in granulomatous reaction, active matrix metalloproteinase-9, found in bovine Echinococcus granulosus hydatid cyst wall and fluid.

In addition to the ability of matrix metalloproteinases (MMP) to degrade components of the extracellular matrix and their involvement in pathology-related processes of tissue remodeling, they were recently reported to enhance inflammation by activation of proinflammatory cytokines, or their release from the cell surface. In the work reported here, proteolytic activity previously found for hydatid cysts was further characterized as MMP-9. Active host MMP-9 was found in walls and fluids of bovine hydatid cysts of Echinococcus granulosus in the environment of granulomatous reaction.

Insulin-like growth factor-1 modulation of CaV1.3 calcium channels depends on Ca2+ release from IP3-sensitive stores and calcium/calmodulin kinase II phosphorylation of the alpha1 subunit EF hand.

In neurons, L-type calcium channels (CaV1.2 and CaV1.3) regulate an extensive range of functions.

Evolution of selenium utilization traits.

Background: The essential trace element selenium is used in a wide variety of biological processes. Selenocysteine (Sec), the 21st amino acid, is co-translationally incorporated into a restricted set of proteins. It is encoded by an UGA codon with the help of tRNASec (SelC), Sec-specific elongation factor (SelB) and a cis-acting mRNA structure (SECIS element).

Thrombin inhibitors identified by computer-assisted multiparameter design.

Here, we present a series of thrombin inhibitors that were generated by using powerful computer-assisted multiparameter optimization process. The process was organized in design cycles, starting with a set of randomly chosen molecules. Each cycle combined combinatorial synthesis, multiparameter characterization of compounds in a variety of bioassays, and algorithmic processing of the data to devise a set of compounds to be synthesized in the next cycle.

[Effect of temperature incubation and glycerol addition on the acrosome preservation in human spermatozoa].

Cooling of mammalian sperms to 5 degrees C and subsequent heating to 30 degrees C causes alterations in the integrity of the plasma membrane producing acrosome disruption. This capacity of induction of acrosome reaction (AR) has allowed to evaluate this process in vitro, and has been correlated with induction of AR by follicular fluid and the percentage of in vitro fertilization. In this study, the time necessary to induce AR at 4 degrees C, the need of the increment in temperature to 37 degrees C, and the effect of glycerol to prevent the AR were evaluated.

Prevalence and risk factors for gallstone disease.

Gallstone disease is a main public health problem. The overall prevalence data range from 3.9% in the pre-echographic era to 13.

Linked thioredoxin-glutathione systems in platyhelminths.

The thioredoxin and glutathione systems play a central role in thiol-disulfide redox homeostasis in many organisms by providing electrons to essential enzymes, and defence against oxidative stress. These systems have recently been characterized in platyhelminth parasites, and the emerging biochemical scenario is the existence of linked processes with the enzyme thioredoxin glutathione reductase supplying reducing equivalents to both pathways. In contrast to their hosts, conventional thioredoxin reductase and glutathione reductase enzymes appear to be absent.

Targeting specific PDZ domains of PSD-95; structural basis for enhanced affinity and enzymatic stability of a cyclic peptide.

A cyclic peptide, Tyr-Lys-c[-Lys-Thr-Glu(betaAla)-]-Val, incorporating a beta-Ala lactam side chain linker and designed to target the PDZ domains of the postsynaptic density protein 95 (PSD-95), has been synthesized and structurally characterized by NMR while free and bound to the PDZ1 domain of PSD-95. While bound, the lactam linker of the peptide makes a number of unique contacts outside the canonical PDZ binding motif, providing a novel target for PDZ-domain specificity as well as producing a 10-fold enhancement in binding affinity. Additionally, the cyclization greatly enhances the enzymatic stability, increasing the duration that the peptide inhibits the association between PSD-95 and glutamate receptors, effectively inhibiting the clustering of kainate receptors for over 14 hr after application.

Alternative mRNAs arising from trans-splicing code for mitochondrial and cytosolic variants of Echinococcus granulosus thioredoxin Glutathione reductase.

Thioredoxin and glutathione systems are the major thiol-dependent redox systems in animal cells. They transfer via the reversible oxidoreduction of thiols the reducing equivalents of NADPH to numerous substrates and substrate reductases and constitute major defenses against oxidative stress. In this study, we cloned from the helminth parasite Echinococcus granulosus two trans-spliced mRNA variants that encode thioredoxin glutathione reductases (TGR).

Echinococcus granulosus antigen 5 is closely related to proteases of the trypsin family.

Antigen 5 (Ag5) is a dominant secreted component of the larval stage of Echinococcus granulosus, and is highly immunogenic in human infections. Although the diagnostic value of Ag5 has been thoroughly evaluated, there has been little progress in its molecular characterization and the understanding of its biological role. In the present study, the Ag5 gene was cloned by reverse transcription-PCR on the basis of the amino acid sequences of tryptic fragments.

Recurrence of varus deformity after proximal tibial osteotomy in Blount disease: long-term follow-up.

In a retrospective review of 74 tibial osteotomies performed for Blount disease, the patients were divided into three groups based on age and treatment. Group A (26 osteotomies), 4 years old or younger, and group B (34 osteotomies), older than 4 years, were treated the same with osteotomy and crossed pins. Group C (14 osteotomies), older than 4 years, was treated with osteotomy and external fixator.

Intraspecific heterogeneity in the mini-exon gene localization of Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis from Colombia.

Intraspecific heterogeneity was demonstrated in the mini-exon gene localization from Leishmania (Viannia) panamensis and L. (Viannia) guyanensis. Different karyotypes were detected in human isolates circulating in endemic areas of Colombia.

A 30 year functional follow-up of a neglected congenital clubfoot in an adult: a case report.

Neglected congenital clubfoot in adults has been described in literature, but is not common to see adult patients with this orthopaedic disorder in developed countries with 30 years of follow-up. We report an asymptomatic case of neglected congenital clubfoot in an adult, who is incidentally seeking treatment for her 18-month-old son with congenital clubfoot. Although the cosmetic appearance is unacceptable, this mother remarkably has no functional limitations and for this reason she refuses any surgical treatment for her foot.

Identification and localization of glutathione S-transferase as a potential target enzyme in Brugia species.

Brugia filarial nematodes are pathogenic lymphatic-dwelling parasites that, like other helminths, may modify the host's defense mechanisms by a major detoxification process involving glutathione-binding proteins such as glutathione S-transferases (GSTs). In the present study, soluble extracts of third-stage larvae, adult male and female worms, microfilariae of either B. pahangi or B.

Molecular characterization of P-29, a metacestode-specific component of Echinococcus granulosus which is immunologically related to, but distinct from, antigen 5.

In this work the characterization of P-29, a novel 29 kDa antigen from Echinococcus granulosus is reported. E. granulosus was identified while looking for parasite antigens distinct from those present in hydatid cyst fluid.

Molecular cloning and characterization of a thioredoxin gene from Echinococcus granulosus.

The insert of a clone from a lambdagt11 Echinococcus granulosus (Platyhelminth, Cestoda) protoscolex cDNA library, showed an open reading frame whose deduced protein sequence presents a high homology with all described thioredoxins (TRX). The TRX active site (Trp-Cys-Gly-Pro-Cys) is completely conserved. With a monospecific antibody, selected from a total anti-protoscolex sera by the isolated clone, a 12 kDa polypeptide was immunoprecipitated from a protoscolex total protein extract.

Human isotype antibody responses to an Onchocerca volvulus glutathione S-transferase.

Human isotype specific antibody responses to a recombinant pi-class glutathione S-transferase (Ov24) from Onchocerca volvulus were assessed by ELISA, using a large and well-characterized bank sera (n = 238) from an hyper-endemic area of moderate intensity from Sierra Leone. IgG1, IgG4 and IgA responses, but neither IgG2 nor IgE response, to Ov24 were detected in infected subjects. The relationships between Ov24 antibody levels and skin microfilarial density, number of nodules, age, sex, eosinophil counts and clinical sign of reactive and chronic pathology were analysed using Pearson's correlation coefficient.

Leishmania RNA viruses in Leishmania of the Viannia subgenus.

Karyotype analysis of 69 strains of Leishmania belonging to three species of the Viannia subgenus originating from the southeastern and southwestern regions of Colombia revealed approximately 5.3-kb RNAs in four strains of L. braziliensis and also in the World Health Organization reference strain L.

Molecular characterisation and localisation of an Onchocerca volvulus pi-class glutathione S-transferase.

Glutathione S-transferases (GSTs) constitute a major detoxification mechanism in helminth organisms and are regarded vaccine candidates against helminth infections. Onchocerca volvulus glutathione-binding proteins were purified from the aqueous soluble fraction of homogenised adult females by affinity chromatography on glutathione-agarose. The eluted proteins had a specific GST activity of 1.