Possible participation of calpain in myosin light chain phosphorylation of human platelets

We previously demonstrated that myosin light chain kinase (MLCK) of gizzard is proteolyzed by platelet calpain. It has been also reported that partially cleaved MLCK may phosphorylate myosin light chain (20K) in the absence of calmodulin. Therefore, a possible participation of calpain in 20K phosphorylation was studied in human platelets, utilizing various inhibitors. An epoxy succinate derivative (E-64) or N-ethylmaleimide (NEM), used as calpain antagonist, inhibited 20K phosphorylation of Ca2+-stimulated lysed platelets. A synergistic effect between these calpain antagonists and calmodulin antagonist W-7 was observed. Also, the similar results were obtained in 20K phosphorylation of intact platelets. From these observations, it was suggested that 20K phosphorylation in platelets is mediated by two separate pathways, namely calmodulin and calpain dependent pathways, provided that calpain activity is specifically inhibited by the antagonists used.     

The mating system ofTokunagayusurika akamusi (Diptera; Chironomidae): II. Experimental analysis of male mating behaviour at the resting place

Mating behaviour ofTokunagayusurika akamusi searching at the resting place (lakeside vegetation, although mating also occurs in the air by swarming) was investigated at the shore of Lake Biwa. Coinciding with the arrival of newly emerged adults, previously emerged males walked about to search for mates at the resting place. When a searching male came into contact with a fresh (newly emerged) individual, he attempted to copulate with it regardless of its sex. Consequently, males copulated with fresh females, which were more likely to be virgin at the resting place, suggesting that the first male might contribute best to the fertilization.     

Mating system ofTokunagayusurika akamusi (Diptera: Chironomidae): I. Copulation in the air by swarming and on the ground by searching

Observations on the mating system of the midge,Tokunagayusurika akamusi, revealed mating to occur both in the air by swarming and on the ground by searching. At the shores of Lake Biwa, midges appeared from November to early December. Newly emerged adults arrived at the resting place, lakeside vegetation, in the morning, during which time a number of males also walked about in search of mates. Many copulating pairs were observed at the resting place. Huge swarms occurred chiefly before sunset but the frequency of copulation observed in the swarm was extremely low. It is likely that, in the Lake Biwa population, the proportion of females inseminated by searching males at the resting place was much larger than that by swarming males in the air. Furthermore, by searching, males copulated with younger females than by swarming. The differences between the searching and swarming tactics are discussed.     

The nucleotide sequence of a cDNA clone containing the entire coding region for mouse X-chromosome-linked phosphoglycerate kinase

A clone containing cDNA for X chromosome-linked phosphoglycerate kinase (PGK-1) was isolated from a mouse myeloma cDNA library. The nucleotide (nt) sequence of the cDNA has been determined, and the amino acid (aa) sequence of the enzyme thereby deduced. At the nt level, the coding region of mouse PGK cDNA has 93% homology with human X-linked cDNA and 60% homology with the yeast gene. Mouse PGK-1 protein contains 416 aa and is 98%, 96% and 64% homologous with human, horse, and yeast enzyme sequences, respectively.     

Strain differences of interferon-generating capacity and resistance in toxoplasma-infected mice

To explore a possible correlation between susceptibility to Toxoplasma and interferon (IFN)-generating capacity in mice, we compared the levels of serum IFN induced by stimulation with Toxoplasma lysate antigen (TLA) in different strains of Toxoplasma-infected and uninfected mice. Injection of TLA into five strains of mice with chronic Toxoplasma infection resulted in the release of considerable amounts of IFN into the circulation. Most of these IFN activities were acid labile and not neutralized by sheep antiserum against mouse IFN-alpha/beta, indicating that IFN-gamma was the dominant form produced in this system. In contrast, the majority of IFN induced in uninfected mice was characterized as IFN-alpha/beta by their acid stability and antigenicity. The response of IFN production in Toxoplasma-infected and uninfected mice varied quantitatively depending on the mouse strains examined. C57BL/6 mice were found to be the best producers of both IFN-alpha/beta and IFN-gamma, while BALB/c mice were consistently poor producers of both IFN populations. A/J, DBA/2, and C3H/He mice could be roughly classified as intermediate producers of both IFN populations. C57BL/6 and C3H/He mice showed a significant prolongation of mean survival time following primary or secondary infection with Toxoplasma compared to that of BALB/c mice. However, there was no direct correlation between the susceptibility to Toxoplasma and the levels of serum IFN.     

Heterogeneity of keratin distribution in the oral mucosa and skin of mammals as determined using monoclonal antibodies

Summary The immunohistochemical localization of keratins in the oral epithelia of several mammals was investigated using the monoclonal antibodies to keratins, PKK1 (41–56 kilodaltons) and KL1 (55–57 kilodaltons). The staining patterns obtained in different locations of the oral mucosa and of the skin epidermis were compared. In the papillae on the dorsal surface of the tongue, some areas exhibited marked PKK1 staining, while other area were PKK1 negative. In general, rodent oral epithelia were negative for PKK1 in the basal layer, while comparatively strong PKK1 staining was observed in cells of the upper spinous layer. In the epidermis, positive PKK1 reactions were confined to the basal layer, while KL1 staining was occasionally seen in the basal layer of oral epithelia. In cats, dogs, and monkeys, different PKK1 and KL1 binding patterns were observed in oral epithelia. Also, the distribution in oral epithelia differed from that seen in the epidermis of these animals. In the epidermis, the distribution of PKK1 and KL1 was regular, with PKK1 usually being confined to the basal layer, while KL1 binding was found in the spinous and granular cell layers, and was dependent on the degree of keratinization. In the animals studies, keratin expression as detected by PKK1 and KL1-was different in the skin epidermis and oral epithelia, and the localization of these keratins differed in the various types of oral mucosa.     

Growth Regulation in Dwarf Barley Coleoptiles by the Minor Cell Wall Components, Galactose and Mannose

Sugar compositions of cell walls of dark-grown coleoptiles from12 barley strains, 11 of which were coleoptilar semi-dwarf strains,were analyzed on days 2 and 3 after germination. Major wallcomponents of the 12 strains were arabinose, xylose, and glucosein hemicellulose and cellulose; minor components were galactoseand mannose. The sugar content of each wall component per unit length wasnot correlated to any growth parameters calculated from a logisticequation simulating coleoptile growth, but the relative contentsof galactose and mannose in relation to the total wall sugarcontent was correlated to the growth rate on day 3 and the growthcontinuing period. These facts suggest that growth of these12 barley strains in the late growth stage is regulated by theminor wall components, galactose and mannose. ¹ Dedicated to the late Professor Joji Ashida. (Received October 12, 1982; Accepted January 12, 1983)     

Participation of cytochrome P450 in mutagenic activation of the carcinogen 3'-hydroxymethyl-N,N-dimethyl-4-aminoazobenzene and its N-demethylated compounds by rat liver

Mutagenicity of the hepatocarcinogen 3'-hydroxymethyl-N, N-dimethyl-4-aminoazobenzene (3'-CH2OH-DAB) and its N-demethylated compounds was examined. Rat-liver 9000 X g supernatant (S9) fraction was used together with Salmonella typhimurium TA98 or TA100 as a tester strain. The expression of mutagenicity of 3'-CH2OH-DAB, 3'-hydroxymethyl-N-methyl-4-aminoazobenzene (3'-CH2OH-MAB) and 3'-hydroxymethyl-4-aminoazobenzene (3'-CH2OH-AB) required the presence of both microsomes and cytosol as sources of enzymes as well as NADPH as a cofactor. 3'-CH2OH-AB showed positive mutagenicity on both strains in the presence of liver S9 from untreated rats whereas 3'-CH2OH-DAB and 3'-CH2OH-MAB were negative. The treatment of rats with polychlorinated biphenyls (PCB) or 3-methylcholanthrene (3-MC) resulted in a marked increase in the ability of S9 to activate these three compounds, whereas phenobarbital (PB) induction was not effective, except for the activation of 3'-CH2OH-AB. The mutagenic activities of the three compounds in strain TA98 were considerably decreased by adding cytochrome c to the S9 mixture, but the activation reactions were insensitive to 1-(1-naphthyl)-2-thiourea (NTU) and methimazole, high-affinity flavin-containing monooxygenase (FMO) substrates. Metyrapone and 2-diethylaminoethyl-2,2-diphenylvalerate hydrochloride (SKF-525A, potent inhibitors of cytochrome P450, had no inhibitory effect on the activation of these compounds by S9 from PCB-treated rat livers. In contrast, 7,8-benzoflavone (BF), a specific inhibitor of cytochrome P448, decreased the activities of 3'-CH2OH-DAB and 3'-CH2OH-MAB by 88 and 78%, respectively, but the inhibition was negligible for 3'-CH2OH-AB.     

Genotoxicity of quinone pigments from pathogenic fungi

The genotoxicity and mutagenicity of several kinds of quinone pigments from pathogenic fungi were examined by means of the hepatocyte primary culture (HPC)/DNA repair test and of Ames test with TA98 and TA100. Clear genotoxicity of the two quinone chemicals, xanthomegnin and luteosporin were observed in the HPC/DNA repair test, though definite mutagenicity was not detected in the Salmonella microsome test. These two pigments are thus suspected to be genotoxic carcinogens.     

Release of LH after administration of an analog of synthetic LH-RH in cattle

The $\text{in vivo}$ effect of an analog of LH-RH, (Des-Gly-NH₂¹⁰, Proethylamide⁹)-LH-RH, on LH release, was studied in one bull with azooapermia, and one cow with cystic follicle. The single intravenous injection of 100 μg LH-RH analog caused abrupt and marked increase in serum LH and the high levels of LH were maintained for 3 hours. The highest levels of serum LH were 48 and 114 times as high as the pre-treatment levels in a bull and a cow, respectively. Further studies are being undertaken to evaluate this compound for improving reproductive function in cattle.