Mecanismos de absor����o de amino��cidos e oligopept��dios. Controle e implica����es na dietoterapia humana

The mechanisms involved in the absorption of amino acids and oligopeptides are reviewed regarding their implications in human feedings. Brush border and basolateral membranes are crossed by amino acids and di-tripeptides by passive (facilitated or simple diffusion) or active (Na + or H + co-transporters) pathways. Active Na +-dependent system occurs mainly at brush border and simple diffusion at basolateral, both membranes have the passive facilitated transport. Free-amino acids use either passive or active transport systems whereas di-tripeptides do mainly active (H + co-transporter). Brush border have distinctive transport system for amino acids and di-tripeptides. The former occurs mainly by active Na + dependency whereas the later is active H +-dependent with little affinity for tetra or higher peptides. Free amino acids are transported at different speed by saturable, competitive carriers with specificity for basic, acidic or neutral amino acids. Di and tripeptides have at least two carriers both electrogenic and H +-dependent. The basolateral membrane transport of amino acids is mostly by facilitated diffusion while for di-tripeptides it is an active anion exchange associated process. The main regulation of amino acids and di-tripeptide transport is the presence o substrate at the mucosal membrane with higher the substrate higher the absorption. Di and tripeptides are more efficiently absorbed than free amino acids which in turns are better absorbed than oligopeptides. So di-tripeptides result in better N-retention and is particularly useful in cases of lower intestinal absorption capacity. The non-absorbed peptides are digested and fermented by colonic bacteria resulting short-chain fatty acids, dicarboxylic acids, phenolic compounds and ammonia. Short-chain fatty acid provides energy for colonocytes and bacteria and the ammonia not fixed by bacteria returns to the liver for ureagenesis.

The genome sequence of the gram-positive sugarcane pathogen Leifsonia xyli subsp. xyli

The genome sequence of Leifsonia xyli subsp. xyli, which causes ratoon stunting disease and affects sugarcane worldwide, was determined. The single circular chromosome of Leifsonia xyli subsp. xyli CTCB07 was 2.6 Mb in length with a GC content of 68% and 2,044 predicted open reading frames. The analysis also revealed 307 predicted pseudogenes, which is more than any bacterial plant pathogen sequenced to date. Many of these pseudogenes, if functional, would likely be involved in the degradation of plant heteropolysaccharides, uptake of free sugars, and synthesis of amino acids. Although L. xyli subsp. xyli has only been identified colonizing the xylem vessels of sugarcane, the numbers of predicted regulatory genes and sugar transporters are similar to those in free-living organisms. Some of the predicted pathogenicity genes appear to have been acquired by lateral transfer and include genes for cellulase, pectinase, wilt-inducing protein, lysozyme, and desaturase. The presence of the latter may contribute to stunting, since it is likely involved in the synthesis of abscisic acid, a hormone that arrests growth. Our findings are consistent with the nutritionally fastidious behavior exhibited by L. xyli subsp. xyli and suggest an ongoing adaptation to the restricted ecological niche it inhabits.

Acute and short-term insulin-induced molecular adaptations of GLUT2 gene expression in the renal cortex of diabetic rats

Increased GLUT2 gene expression in the renal proximal tubule of diabetic rats is an adaptive condition, which may be important in the diabetic nephropathy development. We investigated the effects of insulin treatment upon the renal GLUT2 overexpression of diabetic rats. Acute treatment, surprisingly, induced a rapid further increase in GLUT2 mRNA content. Twelve hours after insulin injection, GLUT2 mRNA was twice the value of saline-injected rats (P < 0.001), when GLUT2 protein remained unchanged. In response to short-term treatment, both GLUT2 mRNA and protein were increased in 1-day treated rats (P < 0.05 versus saline-injected), decreasing after that, and reaching, within 6 days, values close to those of non-diabetic rats. Concluding, insulin treatment induced: initially, an additional upregulation of GLUT2 gene expression, involving posttranscriptional modulation; thereafter, downregulation of GLUT2 expression, which returns to non-diabetic levels. The former may be related to increased insulin concentration, the latter may be due to glycemic control. �� 2005 Elsevier B.V. All rights reserved.

From cytoplasm to environment: The inorganic ingredients for the origin of life

Early in its history, Earth's surface developed from an uninhabitable magma ocean to a place where life could emerge. The first organisms, lacking ion transporters, fixed the composition of their cradle environment in their intracellular fluid. Later, though life adapted and spread, it preserved some qualities of its initial environment within. Modern prokaryotes could thus provide insights into the conditions of early Earth and the requirements for the emergence of life. In this work, we constrain Earth's life-forming environment through detailed analysis of prokaryotic intracellular fluid. Rigorous assessment of the constraints placed on the early Earth environment by intracellular liquid will provide insight into the conditions of abiogenesis, with implications not only for our understanding of early Earth but also the formation of life elsewhere in the Universe. Copyright �� 2013, Mary Ann Liebert, Inc. 2013.

Efeitos do glyphosate sobre o crescimento e absor����o de f��sforo pela soja

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

M��todo de Lowry: valida����o e estimativa do c��lculo da incerteza

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Os descaminhos da estrada: a organiza����o do trabalho dos caminhoneiros no porto de Santos

P��s-gradua����o em Ci��ncias Sociais - FFC

S��ntese de hidroxiapatia porosa com nanopart��culas magn��ticas de ��xido de ferro

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

An��lise in silico de um novo ���cluster��� de PKS II Metagen��mico

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Deposi����es irregulares de res��duos da constru����o civil na cidade de Parna��ba - PI

P��s-gradua����o em Geografia - IGCE

Prospec����o de genes com interesse biotecnol��gico

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Flexibilidade fen��tipica do trato digest��rio: efeitos da restri����o alimentar e realimenta����o em frangos

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Proposta de modelo de gest��o de res��duos da constru����o civil para a zona leste da cidade de Teresina - PI

P��s-gradua����o em Geografia - IGCE

Diagn��stico dos res��duos de constru����o e demoli����o: uma contribui����o �� elabora����o e implanta����o da gest��o integrada dos RCD no munic��pio de Guaratinguet�� ��� SP

The problem of solid waste has caused discussions about the huge amount that is generated in Brazilian cities, in particular the waste from construction and demolition (CDW), called spoil. In many cases these wastes are disposed of improperly and even criminally in urban areas, causing serious economic, social and environmental problems. Due to the lack of public policies and appropriate management of such waste came up with the CONAMA, in its resolution n�� 307 of 2002, the obligation of municipalities in deploy the integrated management of construction and demolition wastes for the resolution of problems caused by inadequate management and disposal of such waste. By following a methodology suggested by Pinto & Gonz��lez (2005), with adaptations of other authors, it is proposed in this work the lifting of a diagnosis of the CDW in the municipality of Guaratinguet��-SP, through theoretical analysis and field research, with purpose to guide the public servants in the elaboration and implementation of integrated management. The results must contain information necessary for that end, such as the knowledge of generators, agents, collectors and transporters, disposition areas and the disposal of waste

Diagn��stico dos res��duos de constru����o e demoli����o para elabora����o e implanta����o da gest��o integrada dos RCD no munic��pio de Guanambi ��� BA

Taking as starting the environmental, social and economic impact of construction and demolition waste in Brazilian cities were created legal mechanisms for management and administration, seeking to minimize the impacts to the maximum, since the irregular deposition can be characterized as environmental crime. CONAMA Resolution No. 307 of 2002 establishing the mandatory implementation of an Integrated Management System Construction Waste and Demolition, guiding the classification and designation of the waste generating agents, collection agents and transporters, and the areas of culling and disposal of waste. The technical partnership between the Ministry of Cities, the Environment Ministry and the Caixa Econ��mica Federal, coordinated by Pinto & Gonzales (2005) Management in the work and management of construction waste, proposed a guidance manual to guide the implementation of a System Integrated Management of Construction Waste in Municipalities. The municipality of Guanambi in the state of Bahia, in full economic rise, lacks a waste management of construction and demolition, since there has areas for the disposal of waste being proposed in this paper the diagnosis of waste generation in the municipality as part of the methodology proposed by the work of Pinto & Gonzales (2005).