Distribution of tetracyclic triterpenoids of lanostane group and sterols in the higher fungi especially of the polyporaceae and related families

The fruit bodies of 97 species of wood-rotting fungi, mainly of Polyporaceae and related families, were examined for the distribution of triterpenes and sterols. Triterpene acids of lanostane group were detected exclusively from the fungi causing brown-rot of woods, while sterols were found to occur commonly in both brown-rot and white-rot fungi. The most abundant sterol was found to be ergosta-7,22-dien-3β-ol. The presence and absence of the triterpene acids is discussed from the point of view of fungal phylogeny.     

Induction of glycophorin gene expression in cultured murine erythroleukemia cells

In order to identify the mRNA for mouse glycophorin, mRNA was isolated from immature erythroid cells obtained from the spleens of anemic mice, translated in vitro in mRNA-dependent rabbit reticulocyte lysate, and then immunoprecipitated with a specific antiserum. Glycophorin mRNA was shown to be present only in erythroid cells. In immunofluorescent and in vitro translation studies, it was shown that glycophorin mRNA is absent in uninduced murine erythroleukemia (MEL) cells, but is induced in dimethylsulfoxide-treated differentiating cells.     

Ecology and mating competition influence sexual dimorphism in Tanganyikan cichlids

Sexual selection contributes strongly to the evolution of sexual dimorphism among animal taxa. However, recent comparative analyses have shown that evolution of sexual dimorphism can be influenced by extrinsic factors like mating system and environment, and also that different types of sexual dimorphism may present distinct evolutionary pathways. Investigating the co-variation among different types of sexual dimorphism and their association with environmental factors can therefore provide important information about the mechanisms generating variation in sexual dimorphism among contemporary species. Using phylogenetic comparative analyses comparing 49 species of Tanganyikan cichlid fishes, we first investigated the pairwise relationship between three types of sexual dimorphism [size dimorphism (SSD), colour dimorphism (COD) and shape dimorphism (SHD)] and how they were related to the strength of pre- and post-copulatory sexual selection. We then investigated the influence of ecological features on sexual dimorphism. Our results showed that although SSD was associated with the overall strength of sexual selection it was not related to other types of sexual dimorphism. Also, SSD co-varied with female size and spawning habitat, suggesting a role for female adaptations to spawn in small crevices and shells influencing SSD in this group. Further, COD and SHD were positively associated and both show positive relationships with the strength of sexual selection. Finally, the level of COD and SHD was related to habitat complexity. Our results thus highlight distinct evolutionary pathways for different types of sexual dimorphism and further that ecological factors have influenced the evolution of sexual dimorphism in Tanganyikan cichlid fishes.     

Direct association of messenger RNA-containing ribonucleoprotein particles with membranes of the endoplasmic reticulum in ethionine-treated rat liver.

The administration of ethionine to female rats causes breakdown of hepatic polysomes. The fate of the mRNA molecules after polysome breakdown was investigated by measuring the amount of poly(A)-containing mRNA in membranous and non-membranous fractions obtained from the cytoplasm of ethionine-treated rat liver. The amount of poly(A)-containing mRNA in the membrane fraction of ethionine-treated liver was found to be the same as that of normal liver. When poly(A)-containing mRNAs from various fractions were translated in a wheat germ system and the products were isolated by immunoprecipitation, the albumin-specific mRNA was found exclusively in the membrane fraction of both normal and ethionine-treated livers. The membrane-bound mRNA in ethionine-treated liver, selectively labeled with [14C]orotate, was banded in CsCl gradient centrifugation at 1.42 g/ml which corresponds to the previously reported mRNA-containing ribonucleoprotein particles. From these results, we concluded that even after the polysome disaggregation by ethionine, most of the mRNA of membrane-bound polysomes remains attached to the endoplasmic reticulum membranes independently of ribosomes and the nascent polypeptide chains.     

Activation of latent ribonuclease in the fat-body of fleshfly (Sarcophaga peregrina) larvae on pupation.

A crude extract of the fat-bodies of third-instar larvae of Sarcophaga peregrina (fleshfly) was found to contain latent RNAase (ribonuclease) consisting of RNAase and inhibitor protein that is sensitive to p-chloromercuribenzoic acid. The RNAase activity in the crude extract of fat-bodies became detectable with time after puparium formation, indicating that the inhibitor is selectively inactivated and RNAase is released from the RNAase-inhibitor complex during metamorphosis.