Histidine-based hydrogels via singlet-oxygen photooxidation.

The formation of hydrogels by photosensitized oxidation and crosslinking of histidine-derived polymers is demonstrated for the first time. The photooxidation of pendant His mediated by singlet oxygen was used to promote covalent coupling by its dimerization. As a proof-of-concept, two systems were studied: (i) chondroitin sulfate (CS) functionalized with His, and (ii) an elastin-like peptide (ELP) containing His produced by recombinant techniques. Both materials were crosslinked by irradiation at 425 nm in the presence of Zn-porphyrin derivatives yielding His-based hydrogels. The molecular structure and physicochemical properties of ELP-His and other 5 ELPs with photooxidizable amino acids were studied in silica by computer simulation. A correlation between the protein conformation and its elastic properties is discussed. CS-His hydrogels demonstrate larger storage moduli than ELPs with other amino acids. The obtained results show the potential use of photooxidation to create a new type of His-based hydrogels.

Crystallization, data collection and processing of the chymotrypsin-BTCI-trypsin ternary complex.

A ternary complex of the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI) with trypsin and chymotrypsin was crystallized by the sitting-drop vapour-diffusion method with 0.1 M HEPES pH 7.5, 10%(w/v) polyethylene glycol 6000 and 5%(v/v) 2-methyl-2,4-pentanediol as precipitant. BTCI is a small protein with 83 amino-acid residues isolated from Vigna unguiculata seeds and is able to inhibit trypsin and chymotrypsin simultaneously by forming a stable ternary complex. X-ray data were collected from a single crystal of the trypsin-BTCI-chymotrypsin ternary complex to 2.7 A resolution under cryogenic conditions. The structure of the ternary complex was solved by molecular replacement using the crystal structures of the BTCI-trypsin binary complex (PDB code 2g81) and chymotrypsin (PDB code 4cha) as search models.

Bacterial killing via a type IV secretion system.

Type IV secretion systems (T4SSs) are multiprotein complexes that transport effector proteins and protein-DNA complexes through bacterial membranes to the extracellular milieu or directly into the cytoplasm of other cells. Many bacteria of the family Xanthomonadaceae, which occupy diverse environmental niches, carry a T4SS with unknown function but with several characteristics that distinguishes it from other T4SSs. Here we show that the Xanthomonas citri T4SS provides these cells the capacity to kill other Gram-negative bacterial species in a contact-dependent manner. The secretion of one type IV bacterial effector protein is shown to require a conserved C-terminal domain and its bacteriolytic activity is neutralized by a cognate immunity protein whose 3D structure is similar to peptidoglycan hydrolase inhibitors. This is the first demonstration of the involvement of a T4SS in bacterial killing and points to this special class of T4SS as a mediator of both antagonistic and cooperative interbacterial interactions.

Acompanhamento nutricional de um paciente pediátrico no pós-operatório da correção da Tetralogia de Fallot: estudo de caso / Monitoring nutritional of pediatric patients in the postoperative period of correction of Tetralogic of Fallot: a case study

Este estudo foi realizado com um paciente pediátrico portador da cardiopatia congênita Tetralogia de Fallot. Logo, objetivou-se com esse trabalho demonstrar a conduta nutricional utilizada visando recuperar e/ou manter o estado nutricional, diminuir o risco de complicações cirúrgicas, fornecer aporte adequado de macronutrientes (evitando hipoalimentação ou hiperalimentação) e fornecer aporte adequado de micronutrientes, prevenindo carências nutricionais, que são comuns em crianças cardiopatas. Este caso clínico foi realizado com um paciente do sexo masculino de 2 anos e 8 meses submetido a segunda cirurgia cardíaca desde o nascimento. Após coleta de exames laboratoriais e amostra de líquido pericárdico foi diagnosticado com quilotórax, possivelmente resultante da operação. Foram acompanhados dados do prontuário compostos por história da doença pregressa, história da doença atual, farmacoterapia e resultados de exames bioquímicos. Realizou-se avaliação nutricional por meio de coleta de dados antropométricos de peso, altura e circunferência braquial, além de exame físico. Dentre os resultados encontrados observou-se adequação do estado nutricional nos critérios de peso/idade, peso/estatura e estatura/idade, porém, o indicador do percentual de adequação da circunferência do braço (CB) indicou um grau de desnutrição leve. A dieta recebida pelo paciente era hipercalórica, hiperproteica e hipolipídica conforme as recomendações e como conduta indicada para a complicação pós-cirúrgica apresentada, a dieta branda recebida pelo paciente passou a ser enriquecida com TCM sem AGE. Com essa conduta o paciente apresentou um ganho ponderal, aumentando, assim, posteriormente, a quantidade de TCM da dieta.

This study was conducted with a pediatric patient suffering from congenital heart defects Tetralogy of Fallot. Therefore, the objective of this study was to demonstrate the nutritional used to recover and/or maintain the nutritional status, decrease the risk of surgical complications, provide adequate intake of macronutrients (avoiding hipoalimentação or hiperalimentação) and provide adequate nutrients, preventing nutritional deficiencies, which are common in children with heart disease. This clinical case was performed with a male patient for 2 years and 8 months before the second cardiac surgery since birth. After collection of laboratory examinations and sample of pericardial fluid was diagnosed with chylothorax, possibly resulting from the operation. Patients were followed data from medical records composed of history of the disease history, the history of the current disease, drug therapy and results of biochemical tests. Among the results observed adequacy of nutritional status in the criteria of weight/age, weight/height and height/age, however, the indicator of the percentage of adequacy of arm circumference (CB) indicated a degree of mild malnutrition. The diet received by the patient was hypercaloric and hiperproteica hipolipídica as recommendations and how to conduct indicated for postoperative complication surgery presented, the diet bland received by the patient began to be enriched with TCM without age.

A draft of the human septin interactome.

BACKGROUND: Septins belong to the GTPase superclass of proteins and have been functionally implicated in cytokinesis and the maintenance of cellular morphology. They are found in all eukaryotes, except in plants. In mammals, 14 septins have been described that can be divided into four groups. It has been shown that mammalian septins can engage in homo- and heterooligomeric assemblies, in the form of filaments, which have as a basic unit a hetero-trimeric core. In addition, it has been speculated that the septin filaments may serve as scaffolds for the recruitment of additional proteins. METHODOLOGY/PRINCIPAL FINDINGS: Here, we performed yeast two-hybrid screens with human septins 1-10, which include representatives of all four septin groups. Among the interactors detected, we found predominantly other septins, confirming the tendency of septins to engage in the formation of homo- and heteropolymeric filaments. CONCLUSIONS/SIGNIFICANCE: If we take as reference the reported arrangement of the septins 2, 6 and 7 within the heterofilament, (7-6-2-2-6-7), we note that the majority of the observed interactions respect the "group rule", i.e. members of the same group (e.g. 6, 8, 10 and 11) can replace each other in the specific position along the heterofilament. Septins of the SEPT6 group preferentially interacted with septins of the SEPT2 group (p<0.001), SEPT3 group (p<0.001) and SEPT7 group (p<0.001). SEPT2 type septins preferentially interacted with septins of the SEPT6 group (p<0.001) aside from being the only septin group which interacted with members of its own group. Finally, septins of the SEPT3 group interacted preferentially with septins of the SEPT7 group (p<0.001). Furthermore, we found non-septin interactors which can be functionally attributed to a variety of different cellular activities, including: ubiquitin/sumoylation cycles, microtubular transport and motor activities, cell division and the cell cycle, cell motility, protein phosphorylation/signaling, endocytosis, and apoptosis.