An orally active antidiabetic vanadyl complex, bis(1-oxy-2-pyridinethiolato)oxovanadium(IV), with VO(S2O2) coordination mode; in vitro and in vivo evaluations in rats

According to Pearson's HSAB (hard and soft acids and bases) rule, the vanadyl ion is classified as a hard acid. However, vanadyl-cysteine methyl ester and dithiocarbamate complexes with VO(S2N2) and VO(S4) coordination modes, respectively, that contain bonds with a combination of hard acid (VO2+) and soft base (sulfur) have been found to form stable complexes and exhibit insulin-mimetic activities in in vitro and in vivo evaluations. Based on such observations, a purple bis(1-oxy-2-pyridinethiolato)oxovanadium(IV) (VO(OPT)) complex with VO(S2O2) coordination mode was prepared and found to have a strong insulin-mimetic activity in in vitro evaluation, which followed in vivo effectiveness on intraperitoneal injection and oral administration. Then, we examined the real-time ESR analysis of vanadyl species in the blood of live rats given VO(OPT) by use of the blood circulation monitoring-ESR method. The clearance of vanadyl species from the blood in terms of half-life (t(1/2)) was determined as 15 min in VO(OPT)-treated rats, while t(1/2) of VOSO4-treated rats was 5 min, indicating the long-term acting character of VO(OPT). On the basis of the results, VO(OPT) with VO(S2O2) coordination mode is proposed to be a potent orally active insulin-mimetic complex in treating insulin-dependent diabetes mellitus in experimental animals.     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Responses and adaptation by Nephotettix virescens to monogenic and pyramided rice lines with Grh‐resistance genes

The green leafhopper, Nephotettix virescens (Distant) (Hemiptera: Cicadellidae), occasionally damages rice in Asia either directly, by feeding on the host phloem, or indirectly by transmitting tungro virus. We assessed the nature of resistance against the leafhopper in monogenic and pyramided near‐isogenic rice lines containing the resistance genes Grh2 and Grh4. Only the pyramided line was resistant to leafhopper damage. Leafhopper nymphs and adults had high mortality and low weight gain when feeding on the pyramided line and adults laid few eggs. In contrast, although there was some minor resistance in 45‐day‐old plants that possessed either Grh2 or Grh4 genes, the monogenic lines were generally as susceptible to the leafhopper as the recurrent parent line Taichung65 (T65). Resistance in the pyramided line was stable as the plant aged and under high nitrogen, and affected each of five Philippine leafhopper populations equally. Furthermore, in a selection study, leafhoppers failed to adapt fully to the pyramided resistant line: nymph and adult survival did improve during the first five generations of selection and attained similar levels as on T65, but egg‐laying failed to improve over 10 generations. Our preliminary results suggested that resistance was associated with physiological costs to the plants in some experiments. The results of this study demonstrate the success of pyramiding resistance genes through marker‐assisted breeding, to achieve a strong and potentially durable resistance. We discuss the utility of gene pyramiding and the development of near‐isogenic lines for leafhopper management.     

DNA polymerase β-dependent long patch base excision repair in living cells

We examined a role for DNA polymerase β (Pol β) in mammalian long patch base excision repair (LP BER). Although a role for Pol β is well known in single-nucleotide BER, information on this enzyme in the context of LP BER has been limited. To examine the question of Pol β involvement in LP BER, we made use of nucleotide excision repair-deficient human XPA cells expressing UVDE (XPA-UVDE), which introduces a nick directly 5′ to the cyclobutane pyrimidine dimer or 6-4 photoproduct, leaving ends with 3′-OH and 5′-phosphorylated UV lesion. We observed recruitment of GFP-fused Pol β to focal sites of nuclear UV irradiation, consistent with a role of Pol β in repair of UV-induced photoproducts adjacent to a strand break. This was the first evidence of Pol β recruitment in LP BER in vivo. In cell extract, a 5′-blocked oligodeoxynucleotide substrate containing a nicked 5′-cyclobutane pyrimidine dimer was repaired by Pol β-dependent LP BER. We also demonstrated Pol β involvement in LP BER by making use of mouse cells that are double null for XPA and Pol β. These results were extended by experiments with oligodeoxynucleotide substrates and purified human Pol β.     

Differential expression of Tenomodulin and Chondromodulin-1 at the insertion site of the tendon reflects a phenotypic transition of the resident cells

The insertion site of the tendon to the skeletal element is hypovascular and is one of the most common sites of dysfunction in the musculoskeletal system. However, the resident cells have been poorly defined due to a lack of a specific marker for tenocytes. We previously reported that Tenomodulin (Tnmd) and Chondromodulin-1 (Chm1) are homologous angiogenesis inhibitors and predominantly expressed in the avascular region of tendons and cartilage, respectively. In this study, we analyzed the expression of Tnmd, Chm1, alpha 1 chain of the type I collagen (Col1a1) and alpha 1 chain of the type II collagen (Col2a1) at the insertion site of the Achilles, patellar, or rotator cuff tendons of 1-week-old rabbits by in situ hybridization analysis. Tnmd was co-expressed with Col1a1 in tenocytes of these tendons, while Chm1 and Col2a1 were detected in chondrocytes of the hyaline cartilage. Interestingly, the cell population between Tnmd/Col1a1 positive tenocytes and Chm1/Col2a1 positive chondrocytes expressed Col1a1 but none of the other markers (Tnmd, Chm1, and Col2a1). Red blood cells were exclusively present at the interface between the tendon substance and cartilage in the insertion site of the Achilles tendon. Lack of Tnmd and Chm1 in this newly characterized cell population may allow the transitional zone between the poorly vascularized tendon and cartilage to establish the unique vascular pattern for blood supply.     

Larval development of the oriental lancelet, Branchiostoma belcheri, in laboratory mass culture

We are successfully maintaining a laboratory colony of the lancelet Branchiostoma belcheri bred in the laboratory. Based on living individuals in this mass culture, morphological characteristics from the seven-day larval to benthic juvenile stages have been studied. Most striking was that later larval development of B. belcheri showed great individual variation even in a rather stable culture environment. Metamorphosis first occurred on 60 days post fertilization (dpf) and was continuously observed throughout the present study up to 100 dpf. Morphological traits such as the number of primary gill slits and body size at the start of metamorphosis are apparently affected by culture condition. Body size measured in the largest individuals showed nearly linear growth at 0.087 mm/day. The variability found in larval development calls for caution when developmental stages and chronological ages are compared between populations. However, the developmental flexibility of this animal also raises the possibility that growth and sexual maturation could be controlled artificially in captivity.     

Recruitment of DNA repair synthesis machinery to sites of DNA damage/repair in living human cells

The eukaryotic sliding DNA clamp, proliferating cell nuclear antigen (PCNA), is essential for DNA replication and repair synthesis. In order to load the ring-shaped, homotrimeric PCNA onto the DNA double helix, the ATPase activity of the replication factor C (RFC) clamp loader complex is required. Although the recruitment of PCNA by RFC to DNA replication sites has well been documented, our understanding of its recruitment during DNA repair synthesis is limited. In this study, we analyzed the accumulation of endogenous and fluorescent-tagged proteins for DNA repair synthesis at the sites of DNA damage produced locally by UVA-laser micro-irradiation in HeLa cells. Accumulation kinetics and in vitro pull-down assays of the large subunit of RFC (RFC140) revealed that there are two distinct modes of recruitment of RFC to DNA damage, a simultaneous accumulation of RFC140 and PCNA caused by interaction between PCNA and the extreme N-terminus of RFC140 and a much faster accumulation of RFC140 than PCNA at the damaged site. Furthermore, RFC140 knock-down experiments showed that PCNA can accumulate at DNA damage independently of RFC. These results suggest that immediate accumulation of RFC and PCNA at DNA damage is only partly interdependent.     

The origination events of gametic sexual reproduction and anisogamy

Journal of Ethology - The evolution of gametic sex (meiosis and fertilization) and subsequent transition from isogamy (fusion between two equal-sized gametes) to anisogamy (dimorphism into eggs and...     

Selected anthropometric variables and aerobic fitness as predictors of cardiovascular disease risk in children

The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children.