RNA-Induced Interference with Animal Virus Infection

Some RNAs, including both single- and double-stranded RNAs, when incubated with chick embryo cell culture induce cellular resistance against viruses. Evidence was now obtained indicating that the induction of cellular resistance by RNA depends on the cellular metabolic activity, especially on the synthesis of cellular RNA and protein. Thus, inhibitors of RNA and protein synthesis, actinomycin D and cycloheximide, were found to inhibit the development of an antiviral state when added before, or during the relatively early period of, incubation of the cells with RNA. In the course of induction of cellular resistance, three stages may be distinguished, the priming stage, the developing stage, and the established resistant stage.     

Distribution of 5-HT (serotonin) immunoreactivity in the central nervous system of the inshore hagfish,Eptatretus burgeri

Summary Immunohistochemical techniques were used to study the distribution of serotonin in the central nervous system of the hagfish,Eptatretus burgeri, in order to produce a detailed map of serotonin-containing structures. In the hypothalamus, many serotonin-containing neurons contacted the cerebrospinal fluid. Most of the serotonin-containing cell bodies were located in the raphe region, where they were compactly distributed at the level of the nucleus motorius tegmenti pars anterior but more diffusely distributed at the level of the nucleus motorius tegmenti pars posterior. Serotonin-containing cell bodies and varicose fibers were widely distributed throughout the brain and upper spinal cord segments, but the distribution density was not even. On the basis of its abundance, serotonin can be judged to have an important function in the control of the hagfish central nervous system. From a phylogenetic point of view, serotonin-containing neurons in the raphe region appear to be a common property of all classes of vertebrates studied except the lampreys, whereas serotonin-containing cerebrospinal fluid-contacting neurons may be considered to be a primitive condition in all nonmammalian vertebrates.     

Altered localization of antigen recognized by proteinuriainducing monoclonal antibody in experimental nephrosis

Change in the localization of the antigen recognized by the proteinuria-inducing monoclonal antibody (MA) 5-1-6 in experimental nephrosis was studied by indirect and biotin-avidin immunofluorescence, and immunoperoxidase at light and electron microscopical levels. The proteinuric state was induced by the administration of the aminonucleoside of puromycin (PAN) or adriamycin. The antigen decreased in quantity and/or its distribution changed with an increase in the amount of protein excreted in both experimental models. Recovery from the alterations observed during the development and proteinuria appeared to occur when PAN-induced proteinuria subsided. This antigenic molecule may thus be essential for maintaining the normal permselectivity of glomerular capillary walls.     

Proliferation-dependent reduction of sister-chromatid exchange frequency induced by mitomycin C in human lymphoblastoid cells and its suppression by inhibitors of DNA replication

A high frequency of sister-chromatid exchange (SCE) induced in cells of a human lymphoblastoid cell line, NL3, by 2-h treatment with 1 microM mitomycin C (MMC) was maintained after holding the treated cells in a nonproliferating state for 48 h before cells were transferred into the BrdUrd-containing medium for SCE assay. The same was observed in cells treated with 4-nitroquinoline 1-oxide (4NQO) or ethyl methanesulfonate (EMS). In contrast, when MMC-treated cells were transferred into a growth medium and allowed to proliferate for various periods of time before SCE assay, MMC-induced SCE frequency decreased with time and reached near control level after 48 h. The reduction in SCE was also observed in 4NQO-treated cells, though to a lesser extent, but not in EMS-treated cells. When hydroxyurea or 1-beta-D-arabinofuranosylcytosine was given as a post-MMC treatment during this recovery process, such a reduction of SCE frequency was suppressed and the extent of the suppression appears to be roughly parallel to their ability to inhibit DNA replication. Cycloheximide and 5-azacytidine also exerted a similar inhibitory effect on the reduction of SCE. Benzamide and caffeine had no appreciable effect. Our results indicate that the SCE-forming lesions induced by MMC can be eliminated only in proliferating cells, probably during DNA replication.     

Refined genetic analysis of the region II che mutants in Salmonella typhimurium

Summary From a detailed complementation analysis of the region II che mutants of Salmonella typhimurium, we have located five che genes, cheA, cheW, cheR, cheB, and cheY. We have shown that corrections are required in the previous assignment of the mutations in four strains: both SL2514 and SL2515 which have been reported to be cheY mutants are cheR mutants, SL2539 is not a cheA but a cheW mutant, and ST171 which has been reported to be a cheZ mutant is a double mutant with defects in both cheA and cheB. Since ST171 is the only cheZ mutant so far isolated, the idea that the cheZ gene might play an essential role in chemotaxis in S. typhimurium as in Escherichia coli has lost its experimental basis. Furthermore, a number of deletion mutants in region II resulting from the excision of Tn10 have been isolated and analysed. From these experiments, we propose that the gene order in region II is flaK-flaE-motA-motB-cheA-cheW-cheR-cheB-cheY-flaM-flaC, which is identical with that in E. coli.     

Three forms of rat liver glucosamine 6-phosphate acetylase and the changes in their levels during development

The three forms (Form I, II and III) of glucosamine 6-phosphate acetylase (glucosamine-phosphate acetyltransferase, EC 2.3.1.4) were present in rat liver. The enzyme activities changed separately during development, in which the successive epigenetic changes were suggested.     

Social and reproductive behavior of three mouthbrooding cardinalfishes,Apogon doederleini,A. niger and A. notatus

Synopsis Social and reproductive behavior of three paternal mouthbrooding cardinalfishes (Apogonidae) were investigated in the shallow marine waters of Shirahama, Japan. The solitary species Apogon doederleini and A. niger bred in transient pairs, in which a male and female associated for only a few hours of each afternoon on less than 5 successive days. The prespawning behavior was the same as the courtship display on days prior to spawning. After spawning, egg-incubating males were usually left alone. The gregarious species Apogon notatus formed territorial lasting pairs, which resided at given sites from dawn to dusk on each day during a period of a month or more. After spawning, the egg-incubating male either continued to stay with his mate in the territory, or left it to enter into an aggregation. In the latter case, the female continued to reside in the territory, pairing with a new male whom she brought from an aggregation. It is suggested that in paternal apogonids the prolonged pair bond and territoriality should have developed only in gregarious species as secondary adaptation for reproductive success: to avoid conspecific interference during spawning.     

Pneumocystis carinii infection in corticosteroid-treated cats

Corticosteroids were administered to produce Pneumocystis carinii infection in cats. Six of 10 cats, injected intramuscularly for 97-141 days with 2 mg/cat twice weekly of betamethasone sodium phosphate, developed a light infection with P. carinii. Six of 7 cats, injected intramuscularly for 11-168 days with 10-25 mg/cat weekly of prednisolone acetate, also developed a light infection with P. carinii. There was no significant difference in the infection rate between the sexes and ages of the cats. Using Giemsa staining and Gomori's methenamine silver nitrate stain, P. carinii organisms were indistinguishable morphologically from human and rat P. carinii. The cysts and trophozoites were usually present singly or in small groups, and they always were adhering to the periphery of alveoli. The inflammatory changes were inconspicuous except for the fact that alveolar macrophages often were seen. Corticosteroid-treated cats should be useful in the study of experimental P. carinii infection. This is the first reported case of experimentally induced P. carinii infection in cats.     

Stereoselective hydrolysis of dl-menthyl succinate by gel-entrapped Rhodotorula minuta var. texensis cells in organic solvent

Summary dl-Menthyl succinate was successfully hydrolyzed stereoselectively by Rhodotorula minuta var. texensis cells entrapped within photo-crosslinked or polyurethane resin gels in water-saturated n-heptane. The hydrolyzed product was found to be pure l-menthol. The catalytic activity of the immobilized cells, especially those entrapped in urethane polymers, was far more stable than that of the free cells. The half-life of the polyurethaneentrapped cells was estimated to be 55–63 days in the organic solvent.Dedicated to the 65th birthday od Professor Dr. G. Manecke