Moused-amino-acid oxidase gene: Restriction fragment length polymorphism among mouse strains

Summary Genomic DNA was extracted from mice of 15 strains (A/J, AKR, BALB/c, C3H/He, C57BL/6, CBA/J, CD-1, CF#1, DBA/2, ddY/DAO⁺, ddY/DAO^–, ICR, NC, NZB and NZW) for the examination of the difference in the structure of thed-amino-acid oxidase gene among the mouse strains. The DNAs were digested with restriction endonucleases and analyzed by Southern hybridization usingd-amino-acid oxidase cDNA as a probe. The 15 strains showed the same hybridization patterns in theEcoRV,BamHI orBglII digestion. In theEcoRI digestion, the DBA/2 strain showed a different hybridization pattern from the other 14 strains. In thePvuII andXbaI digestion, C3H/He, CBA/J, ddY/DAO⁺ and NC strains were different from the other 11 strains. In thePstI andHindIII digestion, restriction fragment length polymorphisms were observed, and the 15 strains were classified into four groups according to their hybridization patterns. These results indicate that the 15 strains of mice carry a structurally similard-amino-acid oxidase gene, but there is a variation in its inside sequence among the groups of the strains.     

Discovery of anti-influenza A virus activity of a corynanthe-type indole alkaloid, hirsutine, in vitro and the structure-activity relationship of natural and synthetic analogs

An indole alkaloid, hirsutine (1), was found to exhibit potent inhibitory effect against influenza A virus in vitro, and the essential structural feature for revealing the activity was elucidated by study of the structure-activity relationship using natural and synthetic derivatives of 1.     

Assortative mating in two populations of Short‐tailed Albatross Phoebastria albatrus on Torishima

Assortative mating is an important pre‐mating isolation mechanism that has been observed in some wild populations of seabirds. The Short‐tailed Albatross Phoebastria albatrus is a globally Vulnerable seabird that breeds mainly on Torishima and the Senkaku Islands in the north‐western Pacific Ocean. Our previous studies suggested that two genetically distinct populations exist, one on Torishima and the other on the Senkaku Islands. Recently, however, several un‐ringed birds in subadult plumage have been observed breeding on Torishima in the Hatsunezaki colony. As almost all birds hatched on Torishima since 1979 have been ringed, the natal site of the un‐ringed birds was suspected to be the Senkaku Islands. Genetic differences between the two populations would reveal the natal sites of un‐ringed birds. By observing the ring status (ringed or un‐ringed) of mating pairs and analysing the mitochondrial DNA (mtDNA) control region 2 of un‐ringed birds, we assessed whether birds that originated from Torishima and the Senkaku Islands achieved pre‐mating isolation. There was a small number of pairs on Torishima that consisted of one ringed and one un‐ringed bird, but the observed number was significantly lower than that expected if ringed and un‐ringed birds mated randomly. Furthermore, mtDNA analyses of nine un‐ringed birds demonstrated that all belonged to a particular haplotype clade from the Senkaku Islands. These results show that birds from Torishima and the Senkaku Islands mate assortatively but that there is incomplete pre‐mating isolation between birds from the two island groups. The pre‐mating isolation of these two populations of Short‐tailed Albatross could arise from differences in the timing of breeding and incompatibility in mating displays. As the divergence between the two populations is unlikely to be sufficient to achieve complete post‐mating isolation, the two groups are likely to be hybridizing. Further studies using molecular and/or behavioural analyses would be required to reveal the evolutionary significance of hybridization between these two populations.     

Nuclear Involvement in Localization of the Initiation Site of Surface Contraction Waves in Xenopus Eggs

The initiation site of surface contraction waves (SCWs) was examined in fertilized, parthenogenetically activated and enucleated Xenopus eggs after either rotation through 90° off the vertical axis or injection of colchicine. In enucleated eggs, SCWs always started from a top site of the egg under all conditions examined. In fertilized or activated eggs, SCWs started, depending on the experimental conditions, from either the sperm entry point, the animal pole region located sideward or the top site of the egg. Histological examinations of fertilized and activated eggs revealed that the nucleus was in most cases positioned close to the initiation site of SCWs under various experimental conditions. It is suggested from these results that the egg cytoplasm has an intrinsic capability of causing the surface to generate SCWs, and that the nucleus is generally involved in localizing the initiation site of SCWs in fertilized or activated Xenopus eggs. A possible mechanism for localizing the initiation site of SCWs in Xenopus eggs is proposed.     

Effects of temperature, aurintricarboxylic acid and cibacron blue on 2',5'-oligoadenylate binding protein (RNase L) activity in rabbit reticulocyte lysates

The binding of p3A4,3'-32P [pCp] to rabbit reticulocyte RNase L can be displaced by the trimer and tetramer triphosphates of 2',5'-oligoadenylates (2-5A). Using assay conditions of protein synthesis, 2-5A trimer or tetramer triphosphates are shown to be equally effective when the displacement is done at 4 degrees C (on ice). In contrast, at 30 degrees C, the tetramer triphosphates still displace whereas the trimer triphosphates become ineffective. When lysates are preincubated at temperature ranging from 4 degrees-37 degrees C, the same results are obtained even when the subsequent displacement is done on ice. Incubation temperature also significantly affects the ability of metabolically stable dyes cibacron blue and aurintricarboxylic acid to inhibit RNase L binding activity. Taken together, these results suggest that rabbit reticulocyte RNase L may assume multiple conformations which are differentially affected by various forms of 2-5A or other compounds.