Synthesis and insulinomimetic activities of novel mono- and tetranuclear oxovanadium(IV) complexes with 3-hydroxypyridine-2-carboxylic acid

Two chargeless VO(IV) complexes with 3-hydroxypyridine-2-carboxylic acid (H2hpic), [VO(Hhpic-O,O)(Hhpic-O,N)(H2O)].3H2O (1) and the cyclic tetramer [(VO)4(mu-(hpic-O,O',N))4(H2O)4].8H3O (2), have been synthesized and characterized by elemental analysis, mass, infrared, electronic absorption, electron spin resonance (ESR) spectroscopies, and X-ray crystallography. Their coordination structures are similar to each other (and 1 is readily transformed into 2), but are quite different from that of bis(pyridine-2-carboxylato)oxovanadium(IV). The magnetic susceptibility of 2 indicates the presence of a weak ferromagnetic intramolecular interaction between the V atoms at low temperature, in addition to a weak antiferromagnetic intermolecular interaction. The ESR signal of 2 was broad, while 1 showed an eight-line hyperfine splitting pattern due to coupling of the unpaired electron with the 51V nucleus (I=7/2). The ESR spectrum and cyclic voltammogram of 2 clearly show that the cyclic tetramer remains intact in solution. The insulinomimetic activity of 1 and 2 was evaluated by means of in vitro measurements of the inhibition of free fatty acid release from epinephrine-treated isolated rat adipocytes. While 1 exerted higher insulinomimetic activity than VOSO4, the activity of 2 was significantly lower than that of VOSO4. Hence 2 appears to retain its cyclic structure during the in vitro test. These results indicate that the rational ligand design for VO complexes might be a promising approach to obtain superior insulinomimetic activity.     

Comparative analysis of plant and animal calcium signal transduction element using plant full-length cDNA data

We obtained 32K full-length cDNA sequence data from the rice full-length cDNA project and performed a homology search against NCBI GenBank data. We have also searched homologs of Arabidopsis and other plants' genes with the databases. Comparative analysis of calcium ion transport proteins revealed that the genes specific for muscle and nerve calcium signal transduction systems (VDCC, IP3 receptor, ryanodine receptor) are very different in animals and plants. In contrast, Ca elements with basic functions in cell responses (CNGC, iGlu receptor, Ca(2+)ATPase, Ca2+/Na(+)-K+ ion exchanger) are basically conserved between plants and animals. We also performed comparative analyses of calcium ion binding and/or controlling signal transduction proteins. Many genes specific for muscle and nerve tissue do not exist in plants. However, calcium ion signal transduction genes of basic functions of cell homeostasis and responses were well conserved; plants have developed a calcium ion interacting system that is more direct than in animals. Many species of plants have specifically modified calcium ion binding proteins (CPK, CRK), Ca2+/phospholipid-binding domains, and calcium storage proteins.     

Covalent molecular imprinting of bisphenol A using its diesters followed by the reductive cleavage with LiAlH(4)

Bisphenol A (BPA) recognition materials were synthesized by a covalent imprinting technique using BPA-dimethacrylate or BPA-diacrylate as the template monomer. Binding sites in the polymers consisted of two hydroxyl groups that are generated by reducing the ester bonds of the template monomer with lithium aluminum hydride. The polymers strongly adsorbed BPA and structurally related compounds, however, other endocrine disruptors were hardly adsorbed. The BPA-dimethacrylate-based polymer interacted with the samples more strongly than the BPA-diacrylate-based polymer.     

Dominance and Immunity in Chimpanzees (Pan troglodytes)

The study reported here examined the effect of dominance status on serum immunoglobulin (IgG and IgM) levels in chimpanzees living in five captive colonies. Blood samples were collected from each individual twice, and agonistic and grooming interactions were observed. After initial group observations, members of four of the five groups were caged singly. Thereafter blood samples were again taken. Both IgG and IgM levels of the animals living in groups were significantly negatively correlated with their dominance status in all five groups. The higher-ranked chimpanzees were likely to show lower levels of IgG and IgM. No such consistent correlation was found between individual Ig levels and frequency of aggressive behaviour or grooming. On transfer to isolated conditions, Ig levels of the chimpanzees did not correlate with their previous dominance status in the groups. Being of high rank is a biological cost for colony-living chimpanzees with regard to immunity levels.     

Normal vaginal flora in chimpanzees (Pan troglodytes): qualitative and quantitative study

Lactobacilli are the predominant microorganisms in the vaginal flora of human beings, and are known to play an important role in protecting them from genital infections. On the other hand, the composition of the vaginal flora differs among laboratory animal species, and lactobacilli are not the predominant vaginal microorganism in many laboratory animals. We speculated that the vaginal flora of chimpanzees would be more similar to those of human beings than to those of other animal species, because chimpanzees are phylogenetically close to human beings, and their reproductive physiology is similar to that of human beings. To clarify our speculation, we examined the development of the vaginal flora in chimpanzees (Pan troglodytes). Streptococci, lactobacilli, and members of the family Bacteroidaceae were the most predominant bacteria in the vagina of mature chimpanzees (9 to 22 years old). During development of the vaginal flora of chimpanzees, the total number of bacteria increased with age and reached a plateau just before sexual maturity (5 to 7 years of age; juvenile period). Lactobacilli were already one of the predominant bacteria before sexual maturity. In mature chimpanzees, the total number of bacteria (aerobes and anaerobes) in the vagina was highest during the swelling phase of the menstrual cycle. During the swelling phase in mature chimpanzees, streptococci, lactobacilli, and Bacteroidaceae were the most frequently isolated (100%) organisms, and the total number of organisms recovered from vaginal specimens from these three groups was the highest. In mature chimpanzees in which the number of bacteria was the highest, lactobacilli were the predominant bacteria. Taken together, these results suggest that these three bacterial groups (streptococci, lactobacilli, and Bacteroidaceae) are indigenous to the vagina of chimpanzees, and chimpanzees would be the most suitable laboratory animals for studying the role of lactobacilli in the vagina of human beings.     

广西中三叠世的"克氏蛤"之订正

描述报道广西中三叠世地层中一类形态相似于克氏蛤（Claraia)的双壳纲化石,经研究,发现海扇科的关键特征丝梳,认为不属于克氏蛤,而可能是Periclaraia属的一个新种,并初步探讨化石层的生态环境,认为可能是相对隔离的盆地中央区,新种是由海扇类进入隔离环境后经特化形成的,新种与克氏蛤的表面相似性是生活习性的相似性导致的形态趋同现象。     

Expression of Musashi-1 in the rat stomach and changes during mucosal injury and restitution

Musashi-1 is involved in maintenance of neural stem cells. In the rat stomach, we found some cells in the luminal compartment of the mucosa that stained positively for Musashi-1. These cells were distinct from other cells of epithelial lineage, except for parietal cells, and coexpressed HES5. The Musashi-1-positive cells exfoliated after damage, while Musashi-1 expression in neck cells were upregulated, and proliferating cells diminished before reappearing and increasing in number thereafter. We conclude that a subpopulation of parietal cells acts as a source of Musashi-1, which contributes to rapid re-epithelization by restoration of stem cells and regulation of cell differentiation.     

Involvement of aberrant DNA methylation on reduced expression of lysophosphatidic acid receptor-1 gene in rat tumor cell lines

Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation, migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, it has been reported that alterations of LPA receptor expression might be important in the malignant transformation of tumor cells. Therefore, to assess an involvement of DNA methylation in reduced expression of the LPA receptor-1 (lpa1) gene, we investigated the expression of the lpa1 gene and its DNA methylation patterns in rat tumor cell lines. Both rat brain-derived neuroblastoma B103 and liver-derived hepatoma RH7777 cells used in this study indicated no expression of lpa1. For the analysis of methylation status, bisulfite sequencing was performed with B103 and RH7777 cells, comparing with other lpa1 expressed cells and normal tissues of brain and liver. The lpa1 expressed cells and tissues were all unmethylated in this region of lpa1. In contrast, both B103 and RH7777 cells were highly methylated, correlating with reduced expression of the lpa1. Treatment with 5-aza 2'-deoxycytidine induced expression of lpa1 gene in B103 and RH7777 cells after 24h. In RH7777 cells treated with 5-aza 2'-deoxycytidine, stress fiber formation was also observed in response to LPA in RH7777 cells, but not in untreated RH7777 cells. These results suggest that aberrant DNA methylation of the lpa1 gene may be involved in its reduced expression in rat tumor cells.