Neurotensin is a regulator of insulin secretion in pancreatic beta-cells

Neurotensin (NT) is secreted from neurons and gastrointestinal endocrine cells. We previously reported that the three NT receptors (NTSRs) are expressed in pancreatic islets and beta cell lines on which we observed a protective effect of NT against cytotoxic agents. In this study, we explored the role of NT on insulin secretion in the endocrine pancreatic beta cells. We observed that NT stimulates insulin secretion at low glucose level and has a small inhibiting effect on stimulated insulin secretion from isolated islets or INS-1E cells. We studied the mechanisms by which NT elicited calcium concentration changes using fura-2 loaded islets or INS-1E cells. NT increases calcium influx through the opening of cationic channels. Similar calcium influxes were observed after treatment with NTSR selective ligands. NT-evoked calcium regulation involves PKC and the translocation of PKCα and PKC? to the plasma membrane. Part of NT effects appears to be also mediated by PKA but not via the Erk pathway. Taken together, these data provide evidence for an important endocrine role of NT in the regulation of the secretory function of beta cells.     

Expression, purification and structural analysis of the Pyrococcus abyssi RNA binding protein PAB1135

Background

Epistatic interactions of multiple single nucleotide polymorphisms (SNPs) are now believed to affect individual susceptibility to common diseases. The detection of such interactions, however, is a challenging task in large scale association studies. Ant colony optimization (ACO) algorithms have been shown to be useful in detecting epistatic interactions.

Findings

AntEpiSeeker, a new two-stage ant colony optimization algorithm, has been developed for detecting epistasis in a case-control design. Based on some practical epistatic models, AntEpiSeeker has performed very well.

Conclusions

AntEpiSeeker is a powerful and efficient tool for large-scale association studies and can be downloaded from http://nce.ads.uga.edu/~romdhane/AntEpiSeeker/index.html.     

Visualizing Early Splenic Memory CD8+ T Cells Reactivation against Intracellular Bacteria in the Mouse

Memory CD8⁺ T cells represent an important effector arm of the immune response in maintaining long-lived protective immunity against viruses and some intracellular bacteria such as Listeria monocytogenes (L.m). Memory CD8⁺ T cells are endowed with enhanced antimicrobial effector functions that perfectly tail them to rapidly eradicate invading pathogens. It is largely accepted that these functions are sufficient to explain how memory CD8⁺ T cells can mediate rapid protection. However, it is important to point out that such improved functional features would be useless if memory cells were unable to rapidly find the pathogen loaded/infected cells within the infected organ. Growing evidences suggest that the anatomy of secondary lymphoid organs (SLOs) fosters the cellular interactions required to initiate naive adaptive immune responses. However, very little is known on how the SLOs structures regulate memory immune responses. Using Listeria monocytogenes (L.m) as a murine infection model and imaging techniques, we have investigated if and how the architecture of the spleen plays a role in the reactivation of memory CD8⁺ T cells and the subsequent control of L.m growth. We observed that in the mouse, memory CD8⁺ T cells start to control L.m burden 6 hours after the challenge infection. At this very early time point, L.m-specific and non-specific memory CD8⁺ T cells localize in the splenic red pulp and form clusters around L.m infected cells while naïve CD8⁺ T cells remain in the white pulp. Within these clusters that only last few hours, memory CD8⁺ T produce inflammatory cytokines such as IFN-γ and CCL3 nearby infected myeloid cells known to be crucial for L.m killing. Altogether, we describe how memory CD8⁺ T cells trafficking properties and the splenic micro-anatomy conjugate to create a spatio-temporal window during which memory CD8⁺ T cells provide a local response by secreting effector molecules around infected cells.     

Brief communication: Study of noncarious cervical tooth lesions in samples of prehistoric,historic, and modern populations from the South of France

Noncarious tooth lesions (NCTL) are frequent findings in contemporary dental practices. Unlike other dental and periodontal diseases, NCTL have not been studied in an anthropological context. The purpose of the present study was to compare the prevalence of NCTL in three archaeological samples from the Copper Age and Middle Ages and in subjects examined in three dental practices. Both archaeological samples and dental-practice subjects were from southern France. In the archaeological sample group, no NCTL were detected in 3,927 teeth from 259 individuals. In the dental-practice group, prevalence rates were in agreement with current epidemiological data. Our data also suggest that prevalence of NCTL increases with age and is higher in females. Premolars were the most affected tooth type. Occurrence of NCTL has long been attributed to toothbrushing and to erosion by intrinsic and extrinsic acids. More recently, occlusal stress associated with tooth flexure has been implicated. The reasons underlying the total absence of NCTL in archaeological samples are discussed. The most likely explanations involve differences in lifestyle, diet, and dental condition.     

Comparison of techniques for the measurement of skin temperature during exercise in a hot,humid environment

Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual''s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes) for the measurement of peripheral (bicep) and central (abdominal) skin temperature. Young men and women (N = 30) were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO₂max) of cycling in a hot (39±2°C), humid (45±5% RH) environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5) were a better index of wired than was thermal imaging (3.5), For the bicep skin temperature the limits of agreement was similar between data loggers (1.9) and thermal (1.9), suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35°C, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects.     

Genome sequence of the clover-nodulating Rhizobium leguminosarum bv. trifolii strain SRDI943.

Rhizobium leguminosarum bv. trifolii SRDI943 (strain syn. V2-2) is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from a root nodule of Trifolium michelianum Savi cv. Paradana that had been grown in soil collected from a mixed pasture in Victoria, Australia. This isolate was found to have a broad clover host range but was sub-optimal for nitrogen fixation with T. subterraneum (fixing 20-54% of reference inoculant strain WSM1325) and was found to be totally ineffective with the clover species T. polymorphum and T. pratense. Here we describe the features of R. leguminosarum bv. trifolii strain SRDI943, together with genome sequence information and annotation. The 7,412,387 bp high-quality-draft genome is arranged into 5 scaffolds of 5 contigs, contains 7,317 protein-coding genes and 89 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.     

The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus

We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource.     

Influence of the Beta-Adrenergic Antagonists Propranolol, Practolol and Oxprenolol On the Proliferation of Rat Jejunal Crypt Cells

Abstract. Beta-adrenergic blockade by quite large doses of propranolol, practolol and oxprenolol, once or continuously applied, does not influence jejunal crypt-cell proliferation in the rat. After a single i.p. injection of 20 mg/kg propranolol or practolol and even of 100 mg/kg practolol, the mitotic index, the labelling index and the duration of the S phase do not differ between treated and untreated control animals nor between animals treated with the different drugs. Continuous application of 30 mg/kg/d propranolol, practolol or oxprenolol for 7 or 14 days does not affect the mitotic and labelling indices either, nor does it change the duration of the cycle of the jejunal crypt cells and its phases as determined by the percent labelled mitoses method. These results are in contrast to those reported previously by Tutton & Helme (1974).