CHAPS solubilization of a G-protein sensitive 5-HT1A receptor from bovine hippocampus

The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high-affinity (Kd = 1.9 nM) and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity (Kd = 9.6 nM) state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the terniary complex rather than to promote its formation. 8-OH DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC(50) values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form.     

Gender differences in hemocyte immune parameters of bivalves: the Sydney rock oyster Saccostrea glomerata and the pearl oyster Pinctada fucata

Many authors have highlighted a high inter-individual variability in immune parameters of marine bivalves. A high number of studies have reported the impact of external factors on hemocytes immune parameters such as temperature, salinity, pollutants or pathogens. However, only a few of them considered the impact of intrinsic parameters such as sex. Therefore, the present study assessed the impact of gender on hemocytes functions on two marine bivalves. Our results led to the conclusion that the gender contributes to this inter-individual variability. When studying the impact of an environmental variable, a pathogen or a pollutant, the sex of each animal should be determined and taken into account in the analysis and interpretation of immune parameters.     

Defective interactions of protein partner with ion channels and transporters as alternative mechanisms of membrane channelopathies

The past twenty years have revealed the existence of numerous ion channel mutations resulting in human pathology. Ion channels provide the basis of diverse cellular functions, ranging from hormone secretion, excitation–contraction coupling, cell signaling, immune response, and trans-epithelial transport. Therefore, the regulation of biophysical properties of channels is vital in human physiology. Only within the last decade has the role of non-ion channel components come to light in regard to ion channel spatial, temporal, and biophysical regulation in physiology. A growing number of auxiliary components have been determined to play elemental roles in excitable cell physiology, with dysfunction resulting in disorders and related manifestations. This review focuses on the broad implications of such dysfunction, focusing on disease-causing mutations that alter interactions between ion channels and auxiliary ion channel components in a diverse set of human excitable cell disease. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé     

EST-based gene discovery in pig: virtual expression patterns and comparative mapping to human

A molecular understanding of porcine reproduction is of biological interest and economic importance. Our Midwest Consortium has produced cDNA libraries containing the majority of genes expressed in major female reproductive tissues, and we have deposited into public databases 21,499 expressed sequence tag (EST) gene sequences from the 3 end of clones from these libraries. These sequences represent 10,574 different genes, based on sequence comparison among these data, and comparison with existing porcine ESTs and genes indicate as many as 4652 of these EST clusters are novel. In silico analysis identified sequences that are expressed in specific pig tissues or organs and confirmed the broad expression in pig for many genes ubiquitously expressed in human tissues. Furthermore, we have developed computer software to identify sequence similarity of these pig genes with their human counterparts, and to extract the mapping information of these human homologues from genome databases. We demonstrate the utility of this software for comparative mapping by localizing 61 genes on the porcine physical map for Chromosomes (Chrs) 5, 10, and 14. The following Accession numbers were assigned to our deposited sequences: BF701840 – BF704551, BF708383, BF708386 – BF713604, BG322266 – BG322271, BI398567 – BI405235, BQ597354 – BQ605166.     

Retracing micro-epidemics of Chagas disease using epicenter regression

Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al espa?ol disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.     

Ecological and evolutionary patterns of freshwater maturation in Pacific and Atlantic salmonines

Reproductive tactics and migratory strategies in Pacific and Atlantic salmonines are inextricably linked through the effects of migration (or lack thereof) on age and size at maturity. In this review, we focus on the ecological and evolutionary patterns of freshwater maturation in salmonines, a key process resulting in the diversification of their life histories. We demonstrate that the energetics of maturation and reproduction provides a unifying theme for understanding both the proximate and ultimate causes of variation in reproductive schedules among species, populations, and the sexes. We use probabilistic maturation reaction norms to illustrate how variation in individual condition, in terms of body size, growth rate, and lipid storage, influences the timing of maturation. This useful framework integrates both genetic and environmental contributions to conditional strategies for maturation and, in doing so, demonstrates how flexible life histories can be both heritable and subject to strong environmental influences. We review evidence that the propensity for freshwater maturation in partially anadromous species is predictable across environmental gradients at geographic and local spatial scales. We note that growth is commonly associated with the propensity for freshwater maturation, but that life-history responses to changes in growth caused by temperature may be strikingly different than changes caused by differences in food availability. We conclude by exploring how contemporary management actions can constrain or promote the diversity of maturation phenotypes in Pacific and Atlantic salmonines and caution against underestimating the role of freshwater maturing forms in maintaining the resiliency of these iconic species.     

Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005

Background

The rising temperature of the world''s oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin.

Methodology/Principal Findings

Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers'' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles.

Conclusions/Significance

Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch''s Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.