Rab Proteins and the Secretory Pathway: The Case of Rab18 in Neuroendocrine Cells

The secretory pathway is a process characteristic of cells specialized in secretion such as endocrine cells and neurons. It consists of different stages that are dependent on specific transport of proteins in vesicular-tubular carriers. Biochemical analyses have unveiled a number of protein families that confer identity to carrier vesicles and specificity to their transport. Among them is the family of Rab proteins, Ras-like small GTPases that anchor to the surface of transport vesicles and participate in vesicle formation from the donor compartment, transport along cytoskeletal tracks, and docking and fusion with the acceptor compartment. All of these functions are accomplished through the recruitment of effector proteins, such as sorting adaptors, tethering factors, kinases, phosphatases, and motors. The numerous Rab proteins have distinct subcellular distributions throughout the endomembrane system, which ensures efficient cargo transfer. Rab proteins act as molecular switches that alternate between a cytosolic GDP-bound, inactive form and a membrane-associated GTP-bound, active conformation. Cycling between inactive and active states is a highly regulated process that enables Rabs to confer spatio-temporal precision to the different stages through which a vesicle passes during its lifespan. This review focuses on our current knowledge on Rab functioning, from their structural features to the multiple regulatory proteins and effectors that control Rab activity and translate Rab function. Furthermore, we also summarize the information available on a particular Rab protein, Rab18, which has been linked to the control of secretory granule traffic in neuroendocrine cells

The ATPase cycle of PcrA helicase and its coupling to translocation on DNA.

The superfamily 1 bacterial helicase PcrA has a role in the replication of certain plasmids, acting with the initiator protein (RepD) that binds to and nicks the double-stranded origin of replication. PcrA also translocates single-stranded DNA with discrete steps of one base per ATP hydrolyzed. Individual rate constants have been determined for the DNA helicase PcrA ATPase cycle when bound to either single-stranded DNA or a double-stranded DNA junction that also has RepD bound. The fluorescent ATP analogue 2'(3')-O-(N-methylanthraniloyl)ATP was used throughout all experiments to provide a complete ATPase cycle for a single nucleotide species. Fluorescence intensity and anisotropy stopped-flow measurements were used to determine rate constants for binding and release. Quenched-flow measurements provided the kinetics of the hydrolytic cleavage step. The fluorescent phosphate sensor MDCC-PBP was used to measure phosphate release kinetics. The chemical cleavage step is the rate-limiting step in the cycle and is essentially irreversible and would result in the bound ATP complex being a major component at steady state. This cleavage step is greatly accelerated by bound DNA, producing the high activation of this protein compared to the protein alone. The data suggest the possibility that ADP is released in two steps, which would result in bound ADP also being a major intermediate, with bound ADP.P(i) being a very small component. It therefore seems likely that the major transition in structure occurs during the cleavage step, rather than P(i) release. ATP rebinding could then cause reversal of this structural transition. The kinetic mechanism of the PcrA ATPase cycle is very little changed by potential binding to RepD, supporting the idea that RepD increases the processivity of PcrA by increasing affinity to DNA rather than affecting the enzymatic properties per se

Foreign bank entry - experience, implications for developing countries, and agenda for further research

In recent years, foreign bank participation has increased tremendously in several developing countries. In Argentina, Chile, the Czech Republic, Hungary and Poland, for example, more than fifty percent of banking assets are now in foreign-controlled banks. In Asia, Africa, The Middle East, and the former Soviet Union, the rate of entry by foreign banks has been slower, but the trend is similar. Although the number of countries welcoming foreign banks is growing, many questions about foreign bank entry are still being debated, including: 1) What draws foreign banks to a country? 2) Which banks expand abroad? 3) What do foreign banks do once they arrive? 4) How does the mode of a bank's entry - for example, as a branch of its parent, or as an independent subsidiary company - affect its behavior? The authors summarize current knowledge on these issues. In addition, since the existing literature focuses heavily on industrial countries, they put forth an agenda for further study of the effects of foreign bank entry in developing countries.Financial Intermediation,Banks&Banking Reform,Payment Systems&Infrastructure,Financial Crisis Management&Restructuring,Banking Law,Banks&Banking Reform,Financial Intermediation,Financial Crisis Management&Restructuring,Banking Law,Municipal Financial Management

Rumen fluke in Irish sheep: prevalence, risk factors and molecular identification of two paramphistome species

peer-reviewedBackground Rumen flukes are trematode parasites found globally; in tropical and sub-tropical climates, infection can result in paramphistomosis, which can have a deleterious impact on livestock. In Europe, rumen fluke is not regarded as a clinically significant parasite, recently however, the prevalence of rumen fluke has sharply increased and several outbreaks of clinical paramphistomosis have been reported. Gaining a better understanding of rumen fluke transmission and identification of risk factors is crucial to improve the control of this parasitic disease. In this regard, a national prevalence study of rumen fluke infection and an investigation of associated risk factors were conducted in Irish sheep flocks between November 2014 and January 2015. In addition, a molecular identification of the rumen fluke species present in Ireland was carried out using an isolation method of individual eggs from faecal material coupled with a PCR. After the DNA extraction of 54 individual eggs, the nuclear fragment ITS-2 was amplified and sequenced using the same primers. Results An apparent herd prevalence of 77.3 % was determined. Several risk factors were identified including type of pasture grazed, regional variation, and sharing of the paddocks with other livestock species. A novel relationship between the Suffolk breed and higher FEC was reported for the first time. The predominant rumen fluke species found was C. daubneyi. Nevertheless, P. leydeni was unexpectedly identified infecting sheep in Ireland for the first time. Conclusions An exceptionally high prevalence of rumen fluke among Irish sheep flocks has been highlighted in this study and a more thorough investigation is necessary to analyse its economic impact. The isolation of individual eggs coupled with the PCR technique used here has proven a reliable tool for discrimination of Paramphistomum spp. This technique may facilitate forthcoming studies of the effects of paramphistomosis on livestock production. The most noteworthy finding was the identification of P. leydeni affecting sheep in Ireland, however further studies are required to clarify its implications. Also, a significant relationship between Suffolk breed and a heavier infection was found, which can be used as a starting point for future research on control strategies of rumen fluke infection.This study was funded by Irish Department of Agriculture, Food and the Marine research stimulus funding; project reference 13/ S/405

Bank lending to small businesses in Latin America : does Bank origin matter?

In recent years foreign bank participation has increased tremendously in Latin America. Some observers argue that foreign bank entry will benefit Latin American banking systems by reducing the volatility of loans and deposits and increasing efficiency. Others are concerned that foreign banks might choose to extend credit only to certain customers, leaving some sectors-such as small businesses-unserved. The authors examine this issue. Using bank-level data for Argentina, Chile, Colombia, and Peru during the mid-1990s, they empirically investigate whether bank origin affects the share and growth rate of bank lending to small businesses. They find that although foreign banks generally lent less to small businesses (as share of total lending) than private domestic banks, the difference is due primarily to the behavior of small foreign banks. The difference was considerably smaller for large and medium-sized banks. And in Chile and Colombia, large foreign banks might actually lend slightly more (as share of total lending) than large domestic banks.Financial Intermediation,Banks&Banking Reform,Financial Crisis Management&Restructuring,Payment Systems&Infrastructure,Economic Theory&Research,Banks&Banking Reform,Financial Intermediation,Financial Crisis Management&Restructuring,Economic Theory&Research,Banking Law

Developmental care: protection approach for early development of preterm infants

OBJETIVO: Revisar ensaios clínicos randomizados, publicados entre 2002 e 2009, sobre a eficácia de intervenções em Cuidado ao Desenvolvimento em recém-nascidos pré-termo em Unidade de Terapia Intensiva Neonatal. FONTES DE DADOS: Foram selecionados estudos randomizados dos bancos de dados Medline, PsycINFO, ISI Web of Science, LILACS e SciELO, usando-se as palavras-chave "developmental care" e "neonate". Realizou-se uma análise metodológica dos estudos, com base nos critérios: randomização, estimativa do tamanho amostral, perda amostral, critérios de inclusão e exclusão, controle de variáveis de confusão, validade dos instrumentos, condição "cega" do pesquisador, realização de seguimento, validades externa e ecológica e cuidados éticos. SÍNTESE DOS DADOS: As intervenções em Cuidado ao Desenvolvimento promoveram melhora em curto prazo nos resultados fisiológicos, comportamentais, neurológicos e clínicos dos recém-nascidos. Observou-se diminuição da reatividade à dor nos recém-nascidos durante procedimentos de pesagem e troca de fraldas. Os pais que receberam intervenções em Cuidado ao Desenvolvimento passaram a apresentar maior senso de competência para cuidar do recém-nascido. Os profissionais treinados em Cuidado ao Desenvolvimento demonstraram melhor desempenho na assistência ao recém-nascido e valorizaram mais os estímulos ambientais, físicos e sociais. CONCLUSÕES: Intervenções em Cuidado ao Desenvolvimento na Unidade de Terapia Intensiva Neonatal promoveram benefícios ao desenvolvimento e saúde dos recém-nascidos pré-termo no período neonatal e no primeiro ano de vida. Em estudos futuros, recomenda-se maior rigor metodológico no que se refere à condição de pesquisador "cego" em relação às intervenções e controle das variáveis de confusão. Estudos prospectivo-longitudinais são necessários para avaliar a eficácia das intervenções em médio e longo prazo no desenvolvimentoABSTRACT OBJECTIVE: To review randomized clinical trials published from 2002 to 2009 focusing on the efficacy of Developmental Care interventions in preterm infants in a Neonatal Intensive Care Unit. DATA SOURCE: Randomized trials were selected from Medline, PsycINFO, ISI Web of Science, LILACS, and SciELO databases using the keywords "developmental care" and "neonate". A critical methodological analysis of the studies was performed based on the following criteria: random allocation, estimate of sample size, drop-out sample, inclusion and exclusion criteria, control of confounding variables, validity of instruments, researcher "blind" condition for intervention group, presence of follow-up, external and ecological validities, and ethical approval. DATA SYNTHESIS: The Developmental Care interventions improved short-term outcomes as physiological, behavioral, neurological and clinical status of newborns. Decreased infants' pain reactivity was noted during weighing and diaper change procedures. Parents exposed to Developmental Care interventions showed higher sense of competence to take care of the newborns. The staff trained in Developmental Care interventions showed better performance when looking after infants and paid more attention to the environmental, physical and social stimuli. CONCLUSIONS: The Developmental Care interventions in a Neonatal Intensive Care Unit promoted beneficial effects on development and health of preterm infants in the neonatal period and the first year of life. In future studies, a higher methodological control of blindness of intervention and confusion variables is recommended. Prospective-longitudinal studies should address the evaluation of this intervention on medium- and long-term developmental outcome