In vivo cross-linking of nucleosomal histones catalyzed by nuclear transglutaminase in starfish sperm and its induction by egg jelly triggering the acrosome reaction.

A histone heterodimer, designated as p28, which contains an Nepsilon(gamma-glutamyl)lysine cross-link between Gln9 of histone H2B and Lys5 or Lys12 of histone H4, is present in starfish (Asterina pectinifera) sperm. Treatment of sperm nuclei with micrococcal nuclease produced soluble chromatin, which was size-fractionated by sucrose-gradient centrifugation to give p28-containing oligonucleosome and p28-free mononucleosome fractions, indicating that the cross-link is internucleosomal. When sperm nuclei were incubated with monodansylcadaverine, a fluorescent amine, in the presence or absence of Ca(2+), histone H2B was modified only in the presence of Ca(2+). Gln9, in the N-terminal region, was modified, but the other Gln residues located in the internal region were not, suggesting that the modification takes place on the surface of the nucleosome core by the in situ action of a Ca(2+)-dependent nuclear transglutaminase. Treatment of sperm with the egg jelly, which activates Ca(2+) influx to induce the acrosome reaction, resulted in a significant elevation of the p28 content in the nucleus. This is the first demonstration of an in vivo activation of transglutaminase leading to the formation of a cross-link in intracellular proteins.     

Photo-induced activation of cytochrome P450/reductase fusion enzyme coupled with spinach chloroplasts

Summary Photoactivation of cytochrome P450 monooxygenase was studied using a combination of spinach chloroplasts and yeast microsomes containing rat P4501A1/yeast reductase fusion enzyme. Under illumination, in the reaction mixture, NADP was reduced, transferring electrons to the P450/reductase fusion enzyme to convert 7-ethoxycoumarin to 7-hydroxycoumarin.     

Purification and immunological properties of cathepsin B in carpCyprinus carpio

Cathepsin B was purified from the crude extract of carp (Cyprinus carpio) hepato-pancreas by the method involving ammonium sulfate fractionation and five sequential chromatographies monitored the activity with Z-Arg-Arg-MCA as a substrate, and the specific activity increased about 11,400 fold with a 2% recovery. Although the homogeneity of the purified cathepsin B was established on Native-PAGE, it migrated as two bands of 29,000 and 25,000 molecular weights by the single and heavy chains on SDS-PAGE, respectively. The monospecific antibody against the homogeneous cathepsin B was purified by the affinity chromatography on cathepsin B-Sepharose 4B, and did not immunologically react with rat cathepsin B, carp cathepsins H and L but only with carp cathepsin B by immunoelectrophoretic blot analysis. As the result of the tissue and liver distributions of cathepsin B, the remarkable immunological reactivities in the extracts of spleen, kidney and hepato-pancreas in carp and those of pacific cod, yellow fin tuna, skip jack tuna and common mackerel in pisces were detected with the anti-carp hepato-pancreas cathepsin B at molecular weight of nearby 29,000 or 25,000.     

Antithrombotic effect of topically applied 3-Oxa-Methano-prostaglandin I1 in the microcirculation and antiplatelet functions of its active form

The antithrombotic effect of topical application of the 3-oxamethano-prostaglandin (PG) I₁ analog, SM-10902 in the microcirculation and in vitro antiplatelet functions of its active form SM-10906 were estimated in comparison with PGI₂ and PGE₁. In rat platelets, SM-10906 evoked accumulation of intracellular cyclic adenosine 3′,5′-monophosphate, and exhibited antiaggregatory and disaggregatory activities, which were all enhanced by the phosphodiesterase inhibitor theophylline. Additionally, SM-10906 was shown to inhibit platelet adhesion to collagen in human platelet-rich plasma. PGI₂ and PGE₁ also showed in vitro antiplatelet effects in the order of PGI₂ > SM-10906 ≥ PGE₁. SM-10902 exhibited a dose-dependent antithrombotic effect in the guinea pig mesenteric arteriole by a topical application, and this activity might be exerted by the antiplatelet functions of SM-10906. Although SM-10906, PGI₂ and PGE₁ also showed the antithrombotic effects, SM-10902 was the most potent. In conclusion, the present studies indicate that an external topical preparation of SM-10902 may be useful for the therapy of peripheral circulatory insufficiency.     

Analysis of randomly isolated cDNAs from developing endosperm of rice (Oryza sativa L.): evaluation of expressed sequence tags,and expression levels of mRNAs

Using a cDNA library prepared from poly(A)⁺ RNA from 10-day-old rice endosperm, partial nucleotide sequences of randomly isolated clones were analyzed. A total of 153 (30.6%) out of 500 cDNA clones showed high amino acid identity to previously identified genes. There was significant redundancy in cDNAs encoding prolamine and glutelin. About 21.0% of the cDNA clones were found to code for seed storage protein genes. Consequently, 37 independent genes were identified. Using cDNA clones encoding glutelin, prolamine, seed allergen, -1,4-glucan branching enzyme, glycine-rich RNA binding protein, metallothionein, non-specific lipid-transfer protein and ubiquitin conjugating enzyme the accumulation of mRNA during rice seed development was compared. Genes associated with seed storage protein and starch biosynthesis were expressed according to expected developmental stages. Glycinerich RNA binding protein genes as well as metallothionein-like protein genes were highly expressed in developing seeds, but low in leaves of whole plants.     

Impaired interleukin-3 (IL-3) response of the A/J mouse is caused by a branch point deletion in the IL-3 receptor alpha subunit gene.

Interleukin-3 (IL-3) alone does not support hematopoietic colony formation of bone marrow cells from the A/J mouse. To elucidate the molecular lesion in A/J mice, we examined expression of the alpha and beta subunits of the IL-3 receptor (IL-3R). While IL-3R beta was normally expressed, IL-3R alpha was not detectable on the surface of A/J-derived cells by antibody staining. Genetic linkage analysis using recombinant inbred mouse strains between A/J and IL-3-responsive C57BL/6 indicated that the IL-3R alpha gene locus was responsible for the impaired IL-3 response in A/J mice. Molecular cloning and characterization of A/J-derived IL-3R alpha cDNA revealed that it lacked the sequence corresponding to exon 8, which encodes 10 amino acid residues in the extracellular domain. The aberrant splicing was due to a 5 base pair deletion at the branch point in intron 7 and was reproduced in heterologous cells by transfecting with an IL-3R alpha minigene carrying the deleterious intron. The A/J-specific abnormal form of IL-3R alpha was localized inside the cells, but not on the cell surface, providing the molecular basis for the impaired IL-3 response in the A/J mouse.     

Immunohistochemical localization of Na+-dependent glucose transporter in the rat digestive tract

Summary Glucose is actively absorbed in the intestine by the action of the Na⁺-dependent glucose transporter. Using an antibody against the rabbit intestinal Na⁺-dependent glucose transporter (SGLT1), we examined the localization of SGLT1 immunohistochemically along the rat digestive tract (oesophagus, stomach, duodenum, jejunum, ileum, colon and rectum). SGLT1 was detected in the small intestine (duodenum, jejunum and ileum), but not in the oesophagus, stomach, colon or rectum. SGLT1 was localized at the brush border of the absorptive epithelium cells in the small intestine. Electron microscopical examination showed that SGLT1 was localized at the apical plasma membrane of the absorptive epithelial cells. SGLT1 was not detected at the basolateral plasma membrane. Along the crypt-villus axis, all the absorptive epithelial cells in the villus were positive for SGLT1, whose amount increased from the bottom of the villus to its tip. On the other hand, cells in the crypts exhibited little or no staining for SGLT1. Goblet cells scattered throughout the intestinal epithelium were negative for SGLT1. These observations show that SGLT1 is specific to the apical plasma membrane of differentiated absorptive epithelial cells in the small intestine, and suggest that active uptake of glucose occurs mainly in the absorptive epithelial cells in the small intestine.     

Cloning and expression of a porcine UDP-GalNAc: polypeptideN-acetylgalactosaminyl transferase

By employing a bovine UDP-N-acetylgalactosamine: polypeptideN-acetylgalactosaminyl transferase (O-GalNAc transferase) cDNA as a probe, we isolated four overlapping cDNAs from a porcine lung cDNA library. Both the nucleotide sequence of the porcine cDNA and the predicted primary structure of the protein (559 amino acids) proved to be very similar to those of the bovine enzyme (95% and 99% identity, respectively). Transient expression of the clone in COS-7 cells, followed by enzymatic activity assays, demonstrated that this cDNA sequence encodes a porcine O-GalNAc transferase. The intracellular O-GalNAc transferase activity was increased approximately 100-fold by transfecting cells with the porcine cDNA.Abbreviations O-GalNAc transferase UDP-N-acetylgalactosamine: polypeptideN-acetylgalactosaminyltransferase - PCR polymerase chain reaction - SDS sodium dodecyl sulfate - PAGE polyacrylamide gel electrophoresis - GnT-III UDP-N-acetylglucosamine: -mannoside -1,4N-acetylglucosaminyltransferase III     

Influence of hydraulic retention time on anaerobic digestion of pretreated sludge

Continuous anaerobic digestion of waste activated sludge pretreated at low temperatures below 100°C increased methane generation by 30%. pH values of the digestion mixture increased, approximately from 0.3 to 0.55 by pretreatment, although its volatile fatty acids concentration was greater than the control. An abrupt increase in propionate : acetate ratio in digestion stage (e.g. from less than 1:1 to over 3.5 :1), provided a reliable indicator for impending failure.This revised version was published online in October 2005 with corrections to the Cover Date.