A new sharpnose pufferfish,Canthigaster flavoreticulata,collected from the South Pacific

A new sharpnose pufferfish,Canthigaster flavoreticulata, is described on the basis of two specimens collected from the Tonga Submarine Ridge in the South Pacific. This species is distinguished from other congeners by having many wavy yellow lines on the dorsal half of the body.     

Genome type analysis of adenovirus type 4 isolates, recently obtained from clinically different syndromes in some areas in Japan

DNA cleavage analyses with EcoRI, HindIII and BamHI were carried out to investigate genome types of recent Ad 4 isolates obtained from acute respiratory disease (8 strains), and ocular disease (11 strains) in Japan. DNA cleavage patterns of all 19 isolates studied were identical regardless of whether they were recovered from respiratory tract or conjunctiva, but were distinct from that of the prototype strain.     

Nucleosidediphosphate-kinase induction by human recombinant IL-2 in mouse NK cells

The ability of human recombinant IL-2 to induce NDP-kinase in mouse NK cells has been studied. A significant increase in the amount of NDP-kinase was observed when the cells were exposed to IL-2 (100 units/ml) for 3 h at 37 degrees C. The enzyme inducting ability of human recombinant IL-2 was similar to that of native mouse IL-2 in the cells. The enzymatic characteristics [chemical requirements for the phosphoenzyme formation and molecular size of two distinct subunits (18,000 and 20,000 daltons)] of NDP-kinase from IL-2 treated cells were similar to those of the enzymes from EAT cells. The enzyme's biological role in the initiation of cell proliferation by IL-2 has been discussed.     

Restriction fragment length polymorphism detected by human salivary amylase cDNA

Summary The plasmid clone which contains human salivary amylase cDNA was used to detect restriction fragment length polymorphisms (RFLPs). After double digestion with Pst 1 and Bam H1, a polymorphism with two alleles was observed. In Japanese, frequencies of these alleles, tentatively called 5.7kb and 6.5kb fragment alleles, are 0.55 and 0.45, respectively.     

Nucleosidediphosphate kinase from Ehrlich ascites tumor cells

A phosphate-incorporating protein has been highly purified from the cytosol of Ehrlich ascites tumor cells (EAT cells). The nitrocellulose membrane method was used to follow the progress of the purification by quantitation of the [32P]phosphorylated form of the protein. The purified protein was identified as an NDP-kinase since it exhibited NDP-kinase activity and had enzyme characteristics in common with other NDP-kinases from various mammalian cells. The purified NDP-kinase was found to have a molecular weight of approximately 76,000 daltons. Moreover, the enzyme appears to consist of two distinct polypeptides (18,000 and 20,000 daltons). This enzyme contained 19 amino acids, with high levels of glycine (9.8%) and lysine (9.0%). The enzyme rapidly formed a [32P]phosphoenzyme when incubated with [gamma-32P]ATP in the presence of Mg2+ (1 mM) at the optimum pH of 7.5 even at low temperature (below 4 degrees C). This phosphoenzyme is an enzyme-bound, high-energy-phosphate intermediate, because ATP was formed from it on incubation with ADP in the presence of Mg2+ (1 mM). This finding suggests that the phosphoenzyme functions as an intermediate in NDP-kinase action.     

Membrane turnover in crab photoreceptors studied by high-resolution scanning electron microscopy and by a new technique of thick-section transmission electron microscopy

Summary Crab photoreceptors were examined after treatment by the osmium-DMSO-osmium method for high-resolution scanning electron microscopy. This technique of specimen preparation was also adapted for transmission electron microscopy, enabling sections up to 1 urn thick to be viewed in a conventional microscope at 75 kV. With appropriate pretreatment, some cytoskeletal elements can be visualised by both techniques. The methods were then used to investigate some of the daily changes known to occur in photoreceptor cell structure. Striking differences were found in the structure of Golgi bodies present in retinula cells during the synthesis and breakdown phases of the daily cycle of photoreceptor membrane turnover. Cyclic changes were also noticed in the mitochondria of retinula cells, and additional evidence was found for a previously proposed model of rhabdomeral microvillus formation.     

Effect of 1,25-dihydroxyvitamin D3 on pancreatic B and D cell function

To investigate the effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on pancreatic B and D cell function in normal rats, 1 microgram of 1,25(OH)2D3 was administered intravenously 20 hours before the experiment. The plasma 1,25(OH)2D3 and calcium concentrations were significantly elevated, and plasma insulin levels also increased in 1,25(OH)2D3-administered rats compared with controls. Glucose-induced insulin and somatostatin release from the isolated pancreas perfused with lower calcium, however, was the same between the 1,25(OH)2D3-administered group and the controls. On the other hand, when the isolated pancreas was perfused with higher calcium, the glucose-induced insulin release was significantly increased in the 1,25(OH)2D3-administered group, while no significant difference in somatostatin release was observed in any group. These results suggest that the sensitivity of pancreatic B cells to glucose perfused with more calcium may increase when 1,25(OH)2D3 has been previously administered. In addition, 1,25(OH)2D3 does not seem to affect the somatostatin release from the pancreatic D cells.     

Effects of prostaglandin E2 and D2 on gastric somatostatin and gastrin secretion

The effects of PGE2 and PGD2 on gastric somatostatin and gastrin releases were investigated using the isolated perfused rat stomach. In the presence of 5.5 mM glucose, the infusion of PGE2 elicited a significant augmentation in somatostatin release, but suppressed gastrin secretion from the perfusate. On the other hand, PGD2 did not affect somatostatin release, although the gastrin secretion decreased significantly, the same as after PGE2 infusion. These results suggest that PGE2 and PGD2 may be important in the regulation of gastric endocrine function, but that PGD2 does not affect gastric somatostatin secretion.