Translucent colony form of the gram-negative, levan-producing bacterium, Aerobacter levanicum

A spontaneously occurring variation of Aerobacter levanicum, affecting the appearance of colonies on sucrose agar (opaque to translucent colony form), has been observed and studied. This appears to be a mutation that is accompanied by a significant increase in levansucrase (EC 2.4.1.10) activity, in levan production, and by a change in some of the properties of levansucrase.     

A new allele, DNASE1*6, of human deoxyribonuclease I polymorphism encodes an Arg to Cys substitution responsible for its instability.

A new allele, DNASE1*6, of human deoxyribonuclease I (DNase I) has been discovered by isoelectric focusing: its gene product has the most cathodic pI of the six electrophoretic variants. Results of DNA sequencing, mismatched PCR-restriction fragment length polymorphism, and transient transfection of the variant construct showed that the mutant was caused by a C-T transition at nucleotide position 1826, resulting in an Arg to Cys substitution at amino acid position 185 of the mature enzyme. The variant isoenzyme, expressed in COS-7 cells, was more labile than the other types. Instability and an increase in the pI value of the variant suggest that a structural alteration, perhaps due to aberrant formation of a disulfide bond, could occur in the enzyme.     

Kinetic study on ESR signal decay of nitroxyl radicals,potent redox probes for in vivo ESR spectroscopy,caused by reactive oxygen species

The effect of the chemical structure of nitroxyl spin probes on the rate at which ESR signals are lost in the presence of reactive oxygen species (ROS) was examined. When the spin probes were reacted with either hydroxyl radical (.OH) or superoxide anion radical (O(2)(.-)) in the presence of cysteine or NADH, the probes lost ESR signal depending on both their ring structure and substituents. Pyrrolidine nitroxyl probes were relatively resistant to the signal decay caused by O(2)(.-) with cysteine/NADH. Signal decay rates for these reactions correlated with reported redox potentials of the nitroxyl/oxoammonium couple of spin probes, suggesting that the signal decay mechanism in both cases involves the oxidation of a nitroxyl group. The apparent rate constants of the reactions between the spin probe and .OH and between the spin probe and O(2)(.-) in the presence of cysteine were estimated using mannitol and superoxide dismutase (SOD), respectively, as competitive standards. The rate constants for spin probes and .OH were in the order of 10(9) M(-1) s(-1), much higher than those for the probes and O(2)(.-) in the presence of cysteine (10(3)-10(4) M(-1) s(-1)). These basic data are useful for the measurement of .OH and O(2)(.-) in living animals by in vivo ESR spectroscopy.     

Molecular identification of GHS-R and GPR38 in Suncus murinus

We previously identified ghrelin and motilin genes in Suncus murinus (suncus), and also revealed that motilin induces phase III-like strong contractions in the suncus stomach in vivo, as observed in humans and dogs. Moreover, repeated migrating motor complexes were found in the gastrointestinal tract of suncus at regular 120-min intervals. We therefore proposed suncus as a small laboratory animal model for the study of gastrointestinal motility. In the present study, we identified growth hormone secretagogue receptor (GHS-R) and motilin receptor (GPR38) genes in the suncus. We also examined their tissue distribution throughout the body. The amino acids of suncus GHS-R and GPR38 showed high homology with those of other mammals and shared 42% amino acid identity. RT-PCR showed that both the receptors were expressed in the hypothalamus, medulla oblongata, pituitary gland and the nodose ganglion in the central nervous system. In addition, GHS-R mRNA expressions were detected throughout the stomach and intestine, whereas GPR38 was expressed in the gastric muscle layer, lower intestine, lungs, heart, and pituitary gland. These results suggest that ghrelin and motilin affect gut motility and energy metabolism via specific receptors expressed in the gastrointestinal tract and/or in the central nervous system of suncus.     

Structure and antitumor activity of an alkali-soluble polysaccharide from Cordyceps ophioglossoides

A water-insoluble extracellular glucan (CO-1) was isolated from the precipitate formed on incubation of the culture filtrate of Cordyceps ophioglossoides at 37 degrees for 19 h. CO-1 was homogeneous as judged by h.p.l.c., electrophoresis, and ultracentrifugation, and the average molecular weight was determined by h.p.l.c. to be 632,000. The 1H- and 13C-n.m.r. and the i.r. spectra indicated that the glucosidic linkages in CO-1 were beta. From the results of methylation analysis, Smith degradation, n.m.r. studies, and enzymic hydrolysis, it was concluded that CO-1 is composed of a backbone of (1----3)-linked beta-D-glucopyranosyl residues with a beta-D-glucopyranosyl group attached to O-6 of every second D-glucopyranosyl residue of the backbone. CO-1 strongly inhibited the growth of Sarcoma 180 solid-type tumor. CO-1 polyalcohol, which was prepared by Smith degradation of CO-1, exhibited more-potent antitumor activity than CO-1. The absorption maximum of Congo Red shifted significantly in the presence of CO-1.     

Purification and characterization of a senile amyloid-related antigenic substance (apoSASSAM) from mouse serum. apoSASSAM is an apoA-II apolipoprotein of mouse high density lipoproteins

Two putative serum precursors which cross-react with antiserum against murine senile amyloid protein (ASSAM) were isolated from the high density lipoprotein (HDL) of normal mouse serum. Apolipoproteins designated "apoSASSAM-1" and "apoSASSAM-2" have the same molecular weight as tissue amyloid fibril protein. ApoSASSAM-1 and apoSASSAM-2 migrate to an intermediate position between apoA-I and apoC on alkaline-urea polyacrylamide gel electrophoresis and are present mainly in HDL apoproteins and to a slight extent in very low density lipoprotein apoproteins when compared to apoC. ApoSASSAM-1 and apoSASSAM-2 are polymorphic; there are two apparent isoproteins of apoSASSAM-1 with isoelectric points of 4.72 and 4.79 and two major isoproteins of apo-SASSAM-2. Subunit bands of ASSAM separated by alkaline-urea polyacrylamide gel electrophoresis and that migrated to the same positions as apoSASSAM-1 and apoSASSAM-2 were labeled by anti-apoSASSAM-1 antiserum. The amino acid compositions of apoSASSAM-1 and apoSASSAM-2 were much the same and closely resembled those of ASSAM and mouse apoA-II. Sequence analysis of apoSASSAM and ASSAM revealed a blocked amino terminus. ApoSASSAM is considered to be a mouse apoA-II and probably transforms to amyloid fibril "ASSAM" in tissues through a process yet to be clarified.     

Regression by ACE inhibition of arteriosclerotic changes induced by chronic blockade of NO synthesis in rats

We previously reported that chronic inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME) induces vascular inflammation at week 1 and produces subsequent arteriosclerosis at week 4 and that cotreatment with an angiotensin-converting enzyme (ACE) inhibitor prevents such changes. In the present study, we tested the hypothesis that treatment with an ACE inhibitor after development of vascular inflammation could inhibit arteriosclerosis in rats. Wistar-Kyoto rats were randomized to four groups: the control group received no drugs, the 4wL-NAME group received L-NAME (100 mg x kg(-1) x day(-1)) for 4 wk, the 1wL + 3wNT group received L-NAME for 1 wk and no treatment for the subsequent 3 wk, and the 1wL + 3wACEI group received L-NAME for 1 wk and the ACE inhibitor imidapril (20 mg x kg(-1) x day(-1)) for the subsequent 3 wk. After 4 wk, we observed significant arteriosclerosis of the coronary artery (medial thickening and fibrosis) and increased cardiac ACE activity in the 1wL + 3wNT group as well as in the 4wL-NAME group, but not in the 1wL + 3wACEI group. In a separate study, we examined apoptosis formation and found that posttreatment with imidapril (20 mg x kg(-1) x day(-1)) or an ANG II AT1-receptor antagonist, CS-866 (5 mg x kg(-1) x day(-1)), induced apoptosis (TdT-mediated nick end-labeling) in monocytes and myofibroblasts appearing in the inflammatory lesions associated with a clear degradation in the heart (DNA electrophoresis). In conclusion, treatment with the ACE inhibitor after 1 wk of L-NAME administration inhibited arteriosclerosis by inducing apoptosis in the cells with inflammatory lesions in this study, suggesting that increased ANG II activity inhibited apoptosis of the cells with inflammatory lesions and thus contributed to the development of arteriosclerosis.