Assignment of 12 loci to rat chromosome 5: evidence that this chromosome is homologous to mouse chromosome 4 and to human chromosomes 9 and 1 (1p arm)

Twelve loci have been assigned to rat chromosome 5: aldolase B (ALDOB), atrial natriuretic factor (ANF = pronatriodilatin, PND), D4RP1, DSI1, galactosyltransferase (GGTB2), glucose transporter (GLUT1), interferon alpha 1 and related interferon alpha (INFA), interferon beta (INFB), lymphocyte-specific protein-tyrosine kinase (LCK), oncogene MOS, alpha 2U-globulin (major urinary protein, MUP), and orosomucoid (ORM, also called alpha 1-acid glycoprotein, AGP). Among these, the interferon alpha and beta genes map in the q22-23 region, which also contains a transformation suppressor gene (SAI1). The other loci reside outside this region. This study also indicated that the rat genome contains 2 LCK genes, unlike the human and murine genomes. These new assignments on rat chromosome 5 demonstrate that this chromosome is highly homologous to mouse chromosome 4 and carries synteny groups conserved on human chromosome 9 (interferon alpha and beta, galactosyltransferase, orosomucoid, and aldolase B genes) and on the short arm of human chromosome 1 (MYCL, glucose transporter, protein kinase LCK, and atrial natriuretic factor genes).     

Hyperthermia inhibits homologous recombination repair and sensitizes cells to ionizing radiation in a time‐ and temperature‐dependent manner

Hyperthermia has long been known as a radio‐sensitizing agent that displays anti‐tumor effects, and has been developed as a therapeutic application. The mechanisms of hyperthermia‐induced radio‐sensitization are highly associated with inhibition of DNA repair. Our investigations aimed to show how hyperthermia inactivate homologous recombination repair in the process of sensitizing cells to ionizing radiation by using a series of DNA repair deficient Chinese Hamster cells. Significant differences in cellular toxicity attributable to hyperthermia at and above 42.5°C were observed. In wild‐type and non‐homologous end joining repair mutants, cells in late S phase showed double the amount heat‐induced radio‐sensitization effects of G1‐phase cells. Both radiation‐induced DNA double strand breaks and chromatin damage resulting from hyperthermia exposure was measured to be approximately two times higher in G2‐phase cells than G0/G1 cells. Additionally, G2‐phase cells took approximately two times as long to repair DNA damage over time than G0/G1‐phase cells. To supplement these findings, radiation‐induced Rad51 foci formations at DNA double strand break sites were observed to gradually dissociate in response to the temperature and time of hyperthermia exposure. Dissociated Rad51 proteins subsequently re‐formed foci at damage sites with time, and occurred in a trend also related to temperature and time of hyperthermia exposure. These findings suggest Rad51's dissociation and subsequent reformation at DNA double strand break sites in response to varying hyperthermia conditions plays an important role in hyperthermia‐induced radio‐sensitization. J. Cell. Physiol. 228: 1473–1481, 2013. © 2012 Wiley Periodicals, Inc.     

Development of a gene-based radiation hybrid map of chicken Chromosome 7 and comparison to human and mouse

To validate the ChickRH6 whole-genome radiation hybrid (WGRH) panel, we constructed a map of chicken Chromosome 7 based on 19 microsatellite markers from the genetic map and 76 ESTs (expressed sequence tags), whose efficient targeted development was made possible by using the ICCARE software. This high-density radiation hybrid (RH) map of a chicken macrochromosome gives us indications on characteristics of ChickRH6. The potential resolution of the panel is 325 kb and the practical resolution of our framework map is 1.3 Mb. Based on these results, a complete framework map of the chicken genome would comprise 1000 markers. The marker order is in good agreement with the genetic map and comparison with the human and mouse sequence maps revealed a number of internal rearrangements.     

IMpRH server: an RH mapping server available on the Web

SUMMARY: The INRA-Minnesota Porcine Radiation Hybrid (IMpRH) Server provides both a mapping tool (IMpRH mapping tool) and a database (IMpRH database) of officially submitted results. The mapping tool permits the mapping of a new marker relatively to markers previously mapped on the IMpRH panel. The IMpRH database is the official database for submission of new results and queries. The database not only permits the sharing of public data but also semi-private and private data.     

Anti-hyperglycemic activity of a TGR5 agonist isolated from Olea europaea

Olive tree (Olea europeaea) leaves are well known for their effect on metabolism in particular as a traditional anti-diabetic and anti-hypertensive herbal drug. These properties are until now only attributed to oleuropein, the major secoiridoid of olive leaves. Here we describe the isolation and the identification of another constituent implicated in the anti-diabetic effect of this plant, i.e. oleanolic acid. We show that this triterpene is an agonist for TGR5, a member of G-protein coupled receptor activated by bile acids and which mediates some of their various cellular and physiological effect. Oleanolic acid lowers serum glucose and insulin levels in mice fed with a high fat diet and it enhances glucose tolerance. Our data suggest that both oleuropein and oleanolic acid are involved in the anti-diabetic effect of olive leaves and further emphasize the potential role of TGR5 agonists to improve metabolic disorders.     

Similar hypotensive responses to resistance exercise with and without blood flow restriction

Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances.