Diazo-reaction positive substance observed in the cortex of Chattonella antiqua

In order to investigate the causative factors responsible for removal of mucous coat from the gill lamellae of young yellowtail, Seriola quinqueradiata by red tide, diazo-reactions were employed for planktons and their media. The concentration of NO2- in the medium containing the raphidophyceae, Chatonella antiqua (ca 2000 cells/ml), was 0.70 +/- 0.05 (mu g/ml +/- SEM). In addition, diazo-reaction positive substances (NOx) which may degenerate the mucous, was highly concentrated in the cortex (perikaryon) of Chattonella antiqua. Morphologically, mucocysts, and chloroplats were likewise present in the cortex. Mucocysts were packed with fine fibrous content. Histochemically, the mucocysts were stained with PAS and had an abundance of nitrogen oxides (NOx). We observed discharge of the fibrous material from the mucocysts. These results suggest that when Chattonella antiqua is passing between the gill lamellae, NOx discharged from the mucocysts may act on the mucous, leading to the degeneration and concomitant removal of the mucous coat from gill lamellae.     

Experimental studies on vertical infection of mice with Japanese encephalitis virus. IV. Effect of virus strain on placental and fetal infection

An experiment was carried out to examine the effect of an inoculated strain of Japanese encephalitis virus on the establishment of experimental vertical infection of mice with this virus. In it, closed-colony mice of the CFW strain were inoculated intravenously with seven strains of the virus at 7 days of pregnancy. After that, an attempt was made to recover the virus from placenta and fetus, so that the infection rate of each strain might be determined. As a result, the infection rate was high for both placenta and fetus in the case of the AS-6 and Sagara strains both of which had undergone three passages in the mouse brain. The placental infection rate was high and the fetal infection rate relatively low in the case of the JaGAr01 and Fuji strains which had undergone 7 and 150 passages, respectively, in the mouse brain. The infection rate was very low for both placenta and fetus in the case of the Nakayama-Yakken strain which had undergone more than 100 passages in the mouse brain. There was no difference in the severity of viremia after inoculation between the AS-6 and Fuji strains. Both placental and fetal infection rates were low in the case of the JaTH160 strain which had undergone passages in mice by intraperitoneal inoculation and which presented a strong peripheral infectivity and induced a severe viremia after inoculation. Neither placental nor fetal infection occurred in the case of the S- strain used as live virus vaccine. These results indicated that placental and fetal infection rates varied from one virus strain to another.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of penicillin G on the electroporation of Rhodococcus rhodochrous CF222

M. SUNAIRI, N. IWABUCHI, K. MURAKAMI, F. WATANABE, Y. OGAWA, H. MUROOKA AND M. NAKAJIMA. 1996. Suitable conditions for the introduction of bacteriophage DNA into cells of Rhodococcus rhodochrous CF222 by electroporation were established, and penicillin G was found to enhance the transfection frequency. When conditions optimal for the parental strain were applied to its colony-morphological mutants, different transfection frequencies were observed. Penicillin G enhanced the transfection frequency of smooth and mucoidal mutants but not of rough mutants.     

Induction and Repair of Damage to DNA in Cucumber Cotyledons Irradiated with UV-B

Photoinduced lesions in DNA, namely, cyclobutane pyrimidinedimers (CPDs) and pyrimidine-(6-4)-pyrimidone photoproducts[(6-4)photoproducts], in cucumber cotyledons that had been irradiatedwith naturally occurring levels of UV-B (290–320 nm) werequantitated by enzyme-linked immunosorbent assays with monoclonalantibodies specific to each type of photolesion. Induction ofthese photolesions was dependent on temperature and their extentwas reduced by simultaneous irradiation with white light. Thedark repair of both types of photolesion was undetectable. Light-dependentremoval of (6-4)photoproducts was very slow, with 50% removalin 4 h. By contrast, 50% of initial CPDs were removed within15 min. Both photorepair processes were dependent on the intensityof white light and were sensitive to temperature. These resultsindicate that high photolyase activity is present in cucumbercotyledons and that repair activities in cucumber cotyledonsare different from those reported in Arabidopsis, in which (6-4)photoproductsare photorepaired more rapidly than CPDs. (Received October 13, 1995; Accepted December 28, 1995)     

Cloning and Characterization of the Murine GPI Anchor Synthesis GenePigf,a Homologue of the HumanPIGFGene

Many eukaryotic proteins are bound to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. Its core backbone, which is conserved in different organisms, is synthesized in the endoplasmic reticulum by the sequential addition of glycan components to phosphatidylinositol. One of the human GPI synthesis genes,PIGF(phosphatidylinositol glycan complementation class F), which is involved late in the synthesis pathway, has been cloned. In this study, we isolated complementary and genomic clones ofPigf,a murine counterpart ofPIGF. Pigfencodes a 219 amino acid protein that complements a class F mutation. ThePigfgene consists of six exons spanning 30 kb and was mapped to chromosome 17 at 17E4–E5. These features are very similar toPIGF,thus demonstrating the interspecies conservation of structure, function, gene organization, and genetic locus between these GPI synthesis genes. The results also extend a region in murine distal chromosome 17 that is syntenic to human chromosome 2p16–p22.     

Evaluation of an automated DNA sequencing system developed in RIKEN

For the advancement of Human Genome Project, we have developed an automated DNA sequencing system HUGA-I. It is composed of several automated instruments and transfer robots connecting them. In this paper we describe the results of the performance evaluation test of HUGA-I. Although some of the system units showed good performances, the total performance of the HUGA-I was about 1/6 of the designed value. By revealing principal reasons of this poor performance, we would like to contribute to the automation in genome analysis, particularly in human genome analysis.Since the sequence technology advanced remarkably in these years, the system units of HUGA-I become older than those which are now commercially available and the throughput of it is out of our expectations. Nevertheless, we believe that it is meaningful to introduce the exact performance of HUGA-I and present the bottle neck points in the automating sequencing processes. Because, automation in the gene analysis is ultimately important, in particular for the analysis of large genomes such as the human genome. The aims of this paper are to introduce the results in performance evaluation of HUGA-I and to elucidate the bottle neck points in the automation of sequencing processes.The authors express their sincere thanks to Mr. Morisada Hayakawa and Mrs. Nobuko Kato for their technical asistance.     

Induction of {alpha}-Amylase is Repressed by Uniconazole, an Inhibitor of the Biosynthesis of Gibberellin, in a Dwarf Mutant of Rice, Waito-C

A system for induction of synthesis of     

Pure Renin. Isolation from hog kidney and characterization.

The pressor enzyme renin (EC 3.4.99.19) was isolated in a pure and stable form from hog kidney by affinity chromatography on a pepstatin/agarose gel followed by three additional steps of conventional chromatography. Destruction of the enzyme by proteolysis during isolation was prevented by chemically eliminating proteases in extracts. The pure preparation was used for the characterization of this enzyme. Renin was found to be a glycoprotein containing glucosamine and possessing binding affinity to concanavalin A. Contrary to previous reports, pure renin is stable at neutral pH either at 4 or -20 degrees for 3 to 8 weeks. It has a molecular weight of 36,400 as determined by equilibrium ultracentrifugation, an isoelectric point of 5.2 and E1%1cm (280 nm) of 9.1. In contrast to crude preparations, the enzyme activity has a broad pH optimum between pH 5.5 and 7.0 for both hog angiotensinogen and the synthetic octapeptide substrate benzyloxycarbonyl-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser-beta-naphthylamide. The rate of formation of angiotensin I from hog angiotensinogen at pH 6.0 and 37 degrees was 267 microng/h/microng of renin, or 2000 Goldblatt units/mg of renin. For the synthetic fluorogenic octapeptide substrate benzyloxycarbonyl-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser-beta-naphthylamide, a Km of 33 micronM and a Vmax of 0.94 micronmol/h/mg of enzyme were obtained at pH 6.5 and 37 degrees.     

Modes of DNA replication primed with the oligomer of palindrome

What is the precise molecular mechanism of semi-conservative DNA replication? After the great efforts of the past 20 years, molecular biology has now established the discontinuous syntheses of daughter DNA on both of the parental strands. In order to explain this type of discontinuous replication, we introduce the concept of a palindromic primer.First we focus our attention on various oligomers (RNA or DNA) which appear usually or occasionally in the process of replication. Then we propose the palindromic nature of these oligomers so as to serve as the primer of DNA synthesis. This postulation gives a theoretical reasoning for the discontinuities of both new strands in the fork region of replication.Subsequently we consider Watson's concatemeric intermediate theory, proposed for the explanation of replicative synthesis of phage T7 DNA. By considering the contribution of some sequence-specific endonuclease(s), we suggest the existence of partial palindromic sequences of bases at the connecting region(s) in which the redundant ends of the respective phage DNA molecules are overlapping. Another theory on the replication of linear chromosomal DNA including the concept of the terminal palindromic sequence of bases is also analyzed from the viewpoint of palindromic primer. Further, some recent experimental approaches, especially on the origin(s) of DNA replication, are shown to favour the concept of a palindromic primer.     

Verdohemoglobin as a substrate for proteases is applicable to assays over a wide pH range.

Verdohemoglobin, a heme-modified derivative readily obtained by ascorbic acid-coupled oxidation of oxyhemoglobin, was found to be a suitable substrate for protease with which assay can be carried out at all pH values. The advantage of verdohemoglobin over such popular substrates as alkali-and-urea-denatured hemoglobin and casein was demonstrated by a pH-profile study with Pronase E.