Ca2+ regulated modulator protein interacting agents: inhibition of Ca2+-Mg2+-ATPase of human erythrocyte ghost.

Agents such as N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), and its derivatives, chlorpromazine and amitriptyline that interact with calcium-regulated modulator protein were found to inhibit not only Ca²⁺ dependent cyclic nucleotide phosphodiesterase but also Ca²⁺-Mg²⁺-ATPase of human erythrocyte ghosts. I₅₀ values of modulator interacting agents for testis modulator-activated, brain modulator-activated and erythrocyte modulator-activated-ATPase are indistinguishable. However, I₅₀ of W-7 for troponin C-activated-ATPase is lower than that for modulator-activated ATPase. The specificity of these agents toward modulator-related enzyme reaction is also shown by the negative effect on modulator-unrelated enzyme system such as erythrocyte ghost protein kinase and Mg²⁺-ATPase. These agents provide a useful tool for elucidating the physiological role of modulator.     

Stereoselective synthesis of 5-O-carbamoylpolyoxamic acid (2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid

One of the constituents of polyoxin J, 2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid (3), has been synthesized stereoselectively from l-sorbopyranose. The amino acid function of 3 was formed in the final stage of the synthesis by reduction of the corresponding α-azido carboxylic acid.     

Induction of body distension by operations on the nervous system in larvae of the swallowtall, Papilio xuthus

Removal of the ganglion or severance of the nerve cords at the thorax in mature larvae of the swallowtail, Papilio xuthus, induced systemic distension of the body by swallowing excess air. Such a distension, however, was never induced by simultaneous extirpation of the brain, suboesophageal ganglion, or frontal ganglion, or by severance of the recurrent nerve. Removal of an abdominal ganglion induced distension of the posterior part of the body accompanied by shrinkage of the anterior part. The latter phenomenon appears to be induced by a different mechanism from that of systemic distension.     

CYCLIC NUCLEOTIDE PHOSPHODIESTERASE OF HUMAN CEREBROSPINAL FLUID

Abstract— Cyclic 3',5'-AMP (cAMP) and cyclic 3',5'–GMP (cGMP) phosphodiesterase activities were found in human cerebrospinal fluid (CSF) using low substrate concentration (0.4μM). More rapid hydrolysis of cGMP than that of cAMP was observed in human CSF. However, cGMP hydrolytic activity of CSF was very much lower (0.3 pmol/min/ml CSF) than that of human cerebral cortex (33.7 nmol/min/g wet cortex). The pH optimum was found to be 8.0 (cGMP phosphodiesterase) and 7.5 (cAMP phosphodiesterase). The maximum stimulation of both cAMP and cGMP phosphodiesterase was achieved at 4 mM-MgCl₂. Cyclic AMP had relatively little effect on the hydrolysis of cGMP in CSF and the cortex, while cGMP inhibited hydrolysis of cAMP in both tissues. Snake venom was found to stimulate cAMP and cGMP phosphodiesterase activity of CSF, by 60% and 110% respectively. This stimulation by snake venom was also observed in the cortex phosphodiesterase, but was not observed in human plasma or thyroid phosphodiesterase. When CSF was applied to Sepharose 6B column, cGMP phosphodiesterase was separated into three different molecular forms. A plot of activity against substrate concentration using peak I (largest molecular size) revealed a high affinity ( K _m= 2.6μM) and a low affinity ( K _m= 100μM) for cAMP suggesting the existence of at least two molecular forms of the enzyme. On the other hand, using a cGMP as substrate the only one K _m value (1.90 μm) was obtained. These K _m values of CSF enzymes described above were close to those obtained from human cerebral cortex preparations. The enzyme under peak I corresponded to the cortex enzyme when judged from its molecular size and stimulation by snake venom. It seems likely from our results that at least a part of CSF phosphodiesterase originates from the central nervous system.     

Two ANGUSTIFOLIA genes regulate gametophore and sporophyte development in Physcomitrella patens

In Arabidopsis thaliana the ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1‐1 and 1‐2). Both PpAN1 genes complemented the A. thaliana an‐1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each PpAN1 gene, using transgenic lines that contained each PpAN1‐promoter– uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for PpAN1‐1 and PpAN1‐2 genes suggested that these genes have partially redundant functions and regulate gametophore height by controlling diffuse cell growth in gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip‐growing protonemata. These results indicate that both PpAN1 genes in P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in gametophore cells of P. patens, transformed lines expressing P. patens α‐tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of gametophores in the PpAN1‐1/1‐2 double‐knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed.     

Synthesis of Fused Cyclopropane-Containing Nucleosides by [1,2]-Hydride Shift Rearrangements and B-Elimination Reactions of Sulfonylated Ribonucleosides

Abstract

(1′R, 3′S and R, 5′S)-4′-Oxo-2′-oxabicyclo[3.1.0]hexan-3′-yl pyrimidines and purines were synthesized from ribonucleosides in 2-5 steps. The configurations of the base moieties in the cyclopropano keto-nucleosides were determined by NOE difference spectroscopy.     

Conversion of d-Glucose into d-Oxybiotin†

2,5-Anhydro-3-azido-3-deoxy-D-xylose dimethyl acetal (XI), the key intermediate for the stereospecific synthesis of d-oxybiotin, was prepared by methanolysis of 3-azido-3-deoxy-1,2-O-isopropylidene-5-O-p-tolylsulfonyl-α-d-xylofuranose (VIIIa) or of 3-azido-3-deoxy-l,2-O-cyclohexylidene-5-0-p-tolylsulfonyl-α-d-xylofuranose (VIIIb).