Characterization of Avian Paramyxoviruses Isolated from Feral Ducks in Northern Japan: The Presence of Three Distinct Viruses in Nature

Seventy-eight strains of avian paramyxoviruses (PMV) were isolated from cloacal and/or tracheal swabs taken from 1,342 feral ducks, comprised of spot-bill ducks, mallards, pintails, teals, falcated teals, wigeons and buffie-heads, in Wakuya-cho, Miyagi Prefecture, Japan, between 1976 and 1979. Five and a half percent of the ducks were positive for virus. Serological and structural characterization indicated that three different avian paramyxoviruses arc prevalent in the Japanese feral duck population. The first group of PMV was Newcastle disease virus (NDV), and in vivo pathogenecity tests in embryonated chicken eggs and 1-day-old chicks revealed that all the NDV strains isolated were avirulent. The second and most prevalent strain was closely related to PMV-4, duck/Hong Kong/D3/75 strain. The viruses of the third group were recovered only from pintails. They cross-reacted antigenically with PMV-3 when antisera to the PMV-3 reference strains, turkey/Wisconsin/68 and parakeet/Netherlands/449/75, were employed. However, no cross-reaction was observed when antiserum to pintail/ Wakuya/20/78, the prototype of this group, was used. The viruses of the third group also differed in viral polypeptide profile from the reference strains of PMV-3.     

Common signal transduction system shared by STE2 and STE3 in haploid cells of Saccharomyces cerevisiae: autocrine cell-cycle arrest results from forced expression of STE2

Induction of STE2 expression using the GAL1 promoter both in a wild-type MATalpha strain and in a MATalpha ste3 strain caused transient cell-cycle arrest and changes in morphology ('shmoo'-like phenotype) in a manner similar to alpha cells responding to alpha-factor. In addition, STE2 expressed in a MATalp[ha ste3 mutant allowed the cell to conjugate with alpha cells but at an efficiency lower than that of wil-type alpha cells. This result indicates that signal(s) generated by alpha-factor in alpha cells can be substituted by signal(s) generated by the interaction of alpha-factor with the expressed STE2 product. When STE2 or STE3 was expressed in a matalpha1 strain (insensitive to both alpha- and a-factors), the cell became sensitive to alpha- or a-factor, respectively, and resulted in morphological changes. These results suggest that STE2 and STE3 are the sole determinants for alpha-factor and a-factor sensitivity, respectively, in this strain. On the other hand, expression of STE2 in an a/alpha diploid cell did not affect the alpha-factor insensitive phenotype. Haploid-specific components may be necessary to transduce the alpha-factor signal. These results are consistent with the idea that STE2 encodes an alpha-factor receptor and STE3 encodes an a-factor receptor, and suggest that both alpha- and a-factors may generate an exchangeable signal(s) within haploid cells.     

B cell growth-promoting activity of recombinant human interleukin 4

Human interleukin 4 (IL-4), also known as B cell stimulatory factor 1, is a T cell-derived glycoprotein consisting of 129 amino acids for which a cDNA has been recently isolated. IL-4 displays little or no B cell growth factor (BCGF) activity in the standard anti-IgM costimulatory assay using suboptimal concentrations of soluble anti-IgM antibody whereas the low m.w. BCGF is very active. When insolubilized anti-IgM was used as the costimulating agent, both IL-4 and the low m.w. BCGF were found to promote B cell proliferation. Human IL-4 is able to induce the proliferation of B lymphocytes preactivated for either 1 day with insolubilized anti-IgM antibody or for 3 days with Staphylococcus aureus strain Cowan I. However, IL-4 is poorly mitogenic for B cells preactivated for 1 day with the Staphylococcus strain whereas the low m.w. BCGF strongly enhances the proliferation of these B cells. These two findings demonstrate that the preactivation signal necessary to induce human B cells to proliferate in response to IL-4 is critical. The increased tritiated thymidine ([3H]dThd) uptake in preactivated B cell cultures with IL-4 reflects cel proliferation because cell cycle analysis demonstrates that IL-4 induces activated B cells to enter the S and G2/M phases of the cell cycle and the addition of IL-4 to preactivated B cell cultures permits the recovery of three- to fourfold more B cells after 4 days of culture. IL-4 and the low m.w. BCGF act in concert to induce the proliferation of anti-IgM-preactivated B cells as demonstrated by [3H]dThd uptake and cell cycle analysis. In striking contrast to the demonstrated antagonistic effect of interferon-gamma on the IL-4-induced expression of the low affinity receptor for IgE (Fc epsilon RL/CD23), on B cells, it was found that interferon-gamma enhanced the IL-4-induced proliferation of anti-IgM-preactivated B cells. Finally, it was found that IL-4 had to be present continuously during the culture period to exert an optimal growth-promoting effect on B cell blasts. As a conclusion, IL-4 is able to induce the proliferation of an appropriately activated subpopulation of human B cells.     

In vitro study of transgenic tobacco expressing Arabidopsis wild type and mutant acetohydroxyacid synthase genes

Summary Genes coding for the enzyme acetohydroxyacid synthase, often referred to as acetolactate synthase (AHAS, ALS; EC 4.1.3.18), from wild type Arabidopsis thaliana and a sulfonylurea-resistant mutant line GH50 (csrl-1; Haughn et al. 1988) were introduced in Nicotiana tabacum. Both genes were expressed at high levels with the 35S promoter. The csrl-1 gene conferred high levels of resistance to chlorsulfuron whereas the wild type gene did not. As selectable markers, chimaeric AHAS genes yielded transgenic plants on chlorsulfuron but at much lower efficiencies than with a chimaeric neomycin phosphotransferase gene on kanamycin (Sanders et al. 1987). Shoot differentiation from leaf discs was delayed on chlorsulfuron by 4–6 weeks. This study indicated a role for mutant AHAS genes in the genetic manipulation of herbicide resistance in transgenic plants but as selectable markers for plant cells undergoing differentiation no advantage over other genes was perceived.     

Molecular characterization and genetic origin of the Brassica napus acetohydroxyacid synthase multigene family

Summary The Brassica napus rapeseed cultivar Topas contains an acetohydroxyacid synthase (AHAS) multigene family consisting of five members (AHAS 1–5). DNA sequence analysis indicate that AHAS1 and AHAS3 share extensive homology. They probably encode the AHAS enzymes essential for plant growth and development. AHAS2 has diverged significantly from AHAS1 and AHAS3 and has unique features in the coding region of the mature polypeptide, transit peptide and upstream non-coding DNA, which raises the possibility that it has a distinct function. AHAS4 and AHAS5 have interrupted coding regions and may be defective. The complexity of the AHAS multigene family in the allotetraploid species B. napus is much greater than reported for Arabidopsis thaliana and Nicotiana tabacum. Analysis of the presumptive progenitor diploid species B. campestris and B. oleracea indicated that AHAS2, AHAS3 and AHAS4 originate from the A genome, whereas AHAS1 and AHAS5 originate from the C genome. Further variation within each of the AHAS genes in these species was found.     

Promotive Effect of C18-Unsaturated Fatty Acids on the Abscission of Bean Petiole Explants

The abscission-promoting effects of C₁₈-unsaturated fatty acidswere studied in bean (Phaseolus vulgaris L. cv. Masterpiece)petiole explants with the junction between the petiole and thepulvinus in the primary leaves in the light. Linolenic, linoleicand oleic acids promoted the abscission of the explants in thelight. Linolenic acid was the most effective among the compoundstested and its promotive effect was evident without any accompanyingincrease in the production of ethylene from the explants, ascompared with non-treated explants. Linolenic acid is easilyconverted to its hydroperoxide during the incubation with explants,as indicated by the formation of the conjugated diene and thegeneration of ethane. The production of ethylene from the explantstreated with linolenic acid was completely inhibited by theaddition of aminoethoxyvi-nylglycine (AVG), but large amountsof ethane were still generated. The promotive effect of linolenicacid was almost eliminated by the addition of scavengers offree radicals. Hydrogen peroxide and tert-butyl hydroperoxidepromoted abscission in the light. From these results, we concludedthat the abscission-promoting effect of linolenic acid are notmediated by the effect of ethylene but by the effect of itshydroperoxide, while the well-established pathway for the biosynthesisof ethylene from S-adenosylmethionine to ethylene, via 1-aminocyclopropane-l-carboxylicacid (ACC), was apparently operative. (Received May 1, 1991; Accepted July 10, 1991)     

Feeding ecology of mandrills (Mandrillus sphinx) in campo animal reserve,Cameroon

A field study on the ecology of mandrills (Mandrillus sphinx) was carried out for 28 months in Cameroon. Fresh food remnants and large quantities of fresh feces were collected by following the groups. Analyses of these products indicated that fruit (including seeds), monocotyledonous plant leaves and insects (especially ants and termites), were frequently eaten. Mandrills mostly ate the plant and animal foods in the lower forest stratum and on the ground. Fallen seeds and monocotyledonous plant leaves were eaten more frequently in the minor fruiting season than in the major fruiting season presumably to compensate for the shortage of fresh fruit during the former. Daily travel distances were shorter during the minor fruiting season than during the major fruiting season, because in the minor fruiting season mandrills forage for small food items, such as the new leaves and piths of monocotyledons and fallen seeds which are sparsely distributed on the ground, while in the major fruiting season they search for widely distributed food such as fruit. The daily pattern of group movement and a food intake experiment suggest that mandrills move and feed continuously throughout the day. Use of fallen seeds and monocotyledonous plant leaves appears to enable mandrills to maintain a terrestrial life in the tropical rain forest. The feeding and ranging characteristics of mandrills are basically similar to those of other baboon species in open land, though their environments differ extremely.