Kinetic properties of rat kidney D-amino acid oxidase associated with peroxisomes

In contrast to hog kidney D-amino acid oxidase, the v vs s plots of D-amino acid oxidase in homogenized rat kidney did not have the form of a rectangular hyperbola, and showed an apparent negative cooperativity. After subcellular fractionation of rat kidney, both of the oxidases in the supernatant fraction and the peroxisomal fraction showed Michaelis-Menten type kinetics. The Km values for D-alanine and D-proline of the peroxisomal fraction were significantly lower than those of the supernatant fraction. The partially purified enzyme from the peroxisomal fraction showed the same kinetic properties as the supernatant fraction. These facts suggest that the two types of rat kidney D-amino acid oxidase were originally identical and that some interaction between the enzyme and peroxisomes is physiologically important for the function of the enzyme.     

Ecology and seasonal distribution of Vibrio parahaemolyticus in aquatic environments of a temperate region

Abstract An environmental survey was done to study the ecology and distribution of Vibrio parahaemolyticus in 5 selected stations in Okayama Prefecture, which included fresh, brackish, and marine aquatic environments. Water and plankton samples were collected monthly for quantitative and qualitative analyses during the period October, 1987 to October, 1989 for V. parahaemolyticus . The pathogen was not detected from fresh water environments. A seasonality of the organism was observed in brackish and marine environments where average salinity ranged between 0.39 and 1.28%.Plankton samples yielded higher densities of V. parahaemolyticus compared with water samples. By applying several enrichment techniques, the pathogen was detected quite frequently during the winter months in the environments with temperatures ranging between 10 and 14°C. The identification following conventional tests, by the API 20E system and by serological methods reveal that the API 20E system is satisfactory to identify V. parahaemolyticus and further confirms that the serological method could be a simpler and more rapid procedure for V. parahaemolyticus identification.     

Cloning of the Promoter Regions of Mouse TGF-{beta} Receptor Genes by Inverse PCR with Highly Overlapped Primers

In order to isolate promoters of mouse TGF-ß receptorgenes, we used inverse PCR with highly overlapped primers correspondingto the 5' sequence of the receptor cDNAs. Nested primer setsonly covered a 30- to 40-base region of the sequences. HinfI-digestedand self-ligated mouse genomic DNA was used as a PCR template.Only one band for each receptor was seen after PCR. The amplifiedDNA fragments could direct luciferase production when the luciferasecoding sequence was ligated after the fragments. The sequenceof the fragment which correspond to the type II receptor showedpartial homology with the promoter region of the human TGF-ßtype II receptor. Thus, the inverse PCR with highly overlappedprimers could be an easy way to isolate the promoter regionsof many genes.     

Anti-inflammatory activity of a globular adiponectin function on RAW 264 cells stimulated by lipopolysaccharide from Aggregatibacter actinomycetemcomitans

Adiponectin is an adipokine with potent anti-inflammatory properties. We previously reported that a globular adiponectin (gAd) suppresses Aggregatibacter actinomycetemcomitans lipopolysaccharide-induced nuclear factor-κB activity, suggesting an anti-inflammatory effect of gAd. In this study, we investigated whether gAd is able to modulate the effect of A. actinomycetemcomitans lipopolysaccharide on cytokine induction in a murine macrophage cell line (RAW 264). The phosphorylation of p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, extracellular signal-regulated kinase, and IκB kinase α/β and the degradation of IκB, which were induced by A. actinomycetemcomitans lipopolysaccharide intoxication, were clearly reduced in gAd-pretreated RAW 264 cells compared with the untreated cells. Expression levels of tumor necrosis factor (TNF)-α and interleukin-10 (IL-10) mRNA were assessed by real-time PCR. Cell-free supernatants were collected after 12 h of stimulation and analyzed by enzyme-linked immunosorbent assay for TNF-α and IL-10. Pretreatment with gAd significantly inhibited the A. actinomycetemcomitans lipopolysaccharide-induced TNF-α mRNA expression and protein secretion. In contrast, pretreatment with gAd significantly enhanced the A. actinomycetemcomitans lipopolysaccharide-induced IL-10 mRNA expression and protein secretion. These data suggest a mechanism for the anti-inflammatory activity of gAd in local inflammatory lesions, such as periodontitis.     

Regulation by 1alpha,25-dihydroxyvitamin D(3) of expression of stanniocalcin messages in the rat kidney and ovary.

Regulation by vitamin D(3) of expression of the genes for stanniocalcins 1 and 2 (STC-1 and STC-2) was studied and their levels were shown to be oppositely regulated in the kidney and to remain unaffected in the ovary. Female rats were treated with calcitriol, the active form of vitamin D(3), and alterations in the levels of STC-1 and STC-2 mRNA were determined by Northern blot analysis in the kidney and ovary where the STC-1-expressing cells have previously been identified by in situ hybridization histochemistry. In the kidney, calcitriol treatment increased the STC-1 mRNA levels more than 3-fold, but decreased the STC-2 message to trace levels. In the ovary, however, both STC-1 and STC-2 mRNA levels were not significantly affected by the calcitriol treatment. These results support the hypotheses that (1) STC-1 and STC-2 have opposite effects on calcium and phosphate homeostasis, namely anti-hypercalcemic and anti-hypocalcemic actions, respectively, and (2) the mammalian stanniocalcin system acquired, in addition to the role in the systemic mineral metabolism, a role in the reproduction system that operates independently of the systemic condition.