Dominance competition through affiliation and support in Japanese macaques: An experimental study

It has been proposed that monkeys direct grooming to high-ranking individuals in an attempt to obtain agonistic support in return. But whether these two categories of interactions are causally related has proven difficult to establish. Part of the problem stems from the fact that in stable groups social relationships reflect an equilibrium state and that behaviors need only be performed at low rates and long intervals to maintain the current social structure. In theory, however, if affiliative and supportive interactions are indeed causally related, it should be possible to accentuate their temporal relation, hence their causal dynamics. For example, destabilizing dominance relations can be expected to induce competition for status and force individuals to deploy behavioral tactics for settling new rank relations. We experimentally induced rank reversals in a captive group of Japanese macaques (Macaca fuscata) composed of three matrilines (A-B-C rank order). A reversed C-A-B order composed of three individuals per matriline was maintained for 2 weeks. The results show the close temporal relation among (i) asserting one’s rank, (ii) competing for access to dominants through affiliation and interferences in affiliation, (iii) receiving support from dominants against lower-ranking individuals, and (iv) supporting dominants against subordinates. These findings are compatible with one version of the affiliation-for-support hypothesis, namely that monkeys affiliate with dominants as a way to assert their position in the hierarchy. In a functional perspective, mutual selfishness provides a better explanation than reciprocal altruism because the possibility that both groomers and supporters derive immediate net benefits cannot be excluded.     

Effects of dark- and light-induced proton gradients in thylakoids on the Q and B thermoluminescence bands

Thermoluminescence experiments have been carried out to study the effect of a transmembrane proton gradient on the recombination properties of the S₂ and S₃ states of the oxygen evolving complex with Q_A ^- and Q_B ^-, the reduced electron acceptors of Photosystem II. We first determined the properties of the S₂Q_A ^- (Q band), S₂Q_B ^- and S₃Q_B ^- (B bands) recombinations in the pH range 5.5 to 9.0, using uncoupled thylakoids. The, a proton gradient was created in the dark, using the ATP-hydrolase function of ATPases, in coupled unfrozen thylakoids. A shift towards low temperature of both Q and B bands was observed to increase with the magnitude of the proton gradient measured by the fluorescence quenching of 9-aminoacridine. This downshift was larger for S₃Q_B ^- than for S₂Q_B ^- and it was suppressed by nigericin, but not by valinomycin. Similar results were obtained when a proton gradient was formed by photosystem I photochemistry. When Photosystem II electron transfer was induced by a flash sequence, the reduction of the plastoquinone pool also contributed to the downshift in the absence of an electron acceptor. In leaves submitted to a flash sequence above 0°C, a downshift was also observed, which was supressed by nigericin infiltration. Thus, thermoluminescence provides direct evidence on the enhancing effect of lumen acidification on the S₃S₂ and S₂S₁ reverse-transitions. Both reduction of the plastoquinone pool and lumen acidification induce a shift of the Q and B bands to lower temperature, with a predominance of lumen acidification in non-freezing, moderate light conditions.Abbreviations 9-AA 9-aminoacridine - E_A activation energy - F₀ constant fluorescence level - F_M maximum fluorescence, when all PS-II centers are closed - F_V variable fluorescence (F_M–F₀) - PS I, PS II Photosystem I, photosystem II - PQ plastoquinone - TL thermoluminescence     

Examination through a principal component analysis of the phosphorus exchanges between sediments and water in trophically different reservoirs

Phosphorus exchange at the sediment-water interface coupled with several parameters were assessed in several reservoirs with geologically different catchment basins and different trophic status in Morocco and France.The results showed that these exchanges were regulated by a combination of factors: physical chemical variability of the environment, the geological composition of catchment basins and the trophic status of the lake.In the hypereutrophic Villerest, iron-bound phosphorus is the major form of phosphorus trapped by the sediment whereas, in Moroccan reservoirs, calcium-bound phosphorus prevailed.We suggest that a drastic control of phosphorus inputs into the waters must be done through a large program of dephosphatization of tributaries to avoid Microcystis aeruginosa bloom formation in Villerest (Aleya et al., 1993) and calcium-bound phosphorus dissociation in Moroccan reservoirs with upward release of bioavailable phosphorus.

---

Résumé Les échanges de phosphore au niveau de l'interface eau-sédiment couplés á la distribution temporelle de divers éléments chimiques et biologiques ont été étudiés dans divers réservoirs de niveaux trophiques différents, au Maroc et en France.Nos résultats mettent clairement en évidence une influence directe de l'environnement physico-chimique, de la nature géologique des bassins versants et de l'état trophique du lac sur la dynamique du phosphore au sein de cette interface.De plus, il apparait que dans le lac hypereutrophe de Villerest (Roanne, France), le phosphore est majoritairement complexé au fer alors que dans les retenues marocaines, ce sont les complexes phosphore-calcium qui prédominent.Nous préconisons un contrôle drastique des apports en phosphore á travers l'installation et la multiplication d'unités de déphosphatation afin d'éviter d'une part, la prolifération massive de la Cyanobactérie Microcystis aeruginosa á Villetest (Aleya et al., 1994) et d'autre part la dissociation des complexes phhosphore-calcium au sein des retenues marocaines avec libération de phosphore biodisponible.

     

Transformation of chicory and expression of the bacterial uidA and nptll genes in the transgenic regenerants

Transgenic chicory plants were obtained from different explantsco-cultured with Agrobacterium tumefaciens. Among tap-root,leaf and cotyledonary tissues, etiolated cotyledons showed thegreatest competence for transformation. The Agrobacterium strainsused contained either pGSGLUC1 or pTDE4 as a vector which carryboth the neomycin phosphotransferase II gene (nptll) for kanamycinresistance and ß-glucuronidase gene (uidA) under thecontrol of different promoters. Transformation was confirmedby NPTII enzymatic assay, histochemical analysis of GUS activityand DNA hybridization. Transgenic plants expressed both markergenes in root and shoot tissues. In leaves, GUS activity wasexpressed in all tissue types, whatever the nature of the promoter.Nevertheless, variable heterogeneous patterns of expressionwere observed in the different root tissues. Differential expression of the GUS fusions controlled by thedual TR or the CaMV 35S promoters are discussed. Key words: Chicory, genetic transformation, GUS activity, kanamycin resistance     

5'-(N-Ethylcarboxamido)adenosine Inhibits Ca2+ Influx and Activates a Protein Phosphatase in Bovine Adrenal Chromaffin Cells

Abstract: We investigated the effect of the adenosine receptor agonist 5'-( N -ethylcarboxamido)adenosine (NECA) in catecholamine secretion from adrenal chromaffin cells that exhibit only the A_2b subtype adenosine receptor. NECA reduced catecholamine release evoked by the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP) in a time-dependent manner. Inhibition reached 25% after 30–40-min exposure to NECA. This effect on DMPP-evoked catecholamine secretion was mirrored by a similar (27.7 ± 3.3%), slowly developing inhibition of [Ca²⁺]_i transients induced by DMPP that peaked at 30-min preincubation with NECA. The capacity of the chromaffin cells to buffer Ca²⁺ load was not affected by the treatment with NECA. Short-term treatment with NECA failed both to modify [Ca²⁺]_i levels and to increase endogenous diacylglycerol production, showing that NECA does not activate the intracellular Ca²⁺/protein kinase C signaling pathway. The inhibitory effects of NECA were accompanied by a 30% increase of protein phosphatase activity in chromaffin cell cytosol. We suggest that dephosphorylation of a protein involved in DMPP-evoked Ca²⁺ influx pathway (e.g., L-type Ca²⁺ channels) could be the mechanism of the inhibitory action of adenosine receptor stimulation on catecholamine secretion from adrenal chromaffin cells.     

A Complete Set of Marked Telomeres in Saccharomyces Cerevisiae for Physical Mapping and Cloning

Each telomere in a single strain (S288C) of Saccharomyces cerevisiae was marked with a URA3 containing integrating vector having telomeric TG(1-3) sequences. Efficiency of integrative transformation was enhanced by creating single random double-strand breaks in the integrating vector using DNAseI in the presence of Mn(2+) ions. A total of 327 transformants were screened by CHEF gels of intact chromosomal DNA. Transformants with homology to the vector at particular chromosomal bands were then screened by Southern analysis with several restriction enzymes to confirm telomeric locations. CHEF gels of NotI and/or SfiI digests were also analyzed to determine left or right arm locations. In some cases allelism of marked telomeres was determined genetically. Transformation was performed by lithium acetate and electroporation with varying results. Electroporation resulted in 50% (75/150) of the integrants at the internal URA3 location rather than telomeres. There were also two rearrangements involving URA3 and the telomere of another chromosome. Lithium acetate transformation resulted in fewer integrants at the internal URA3 location (5/84) and no rearrangements. All telomeres were marked with approximately the same efficiency ranging from 0 to 11 hits in the first 240 transformants. These marked telomeres can be used to complete the physical maps of chromosomes in which the telomere regions are absent. The marked telomeres can be cloned with the appropriate restriction enzymes, thus completing the cloning of individual chromosomes for sequencing projects. The analysis of these clones will lead to a better understanding of telomere region biology. The methodology can also be applied to telomeres of other organisms once they are cloned as telomeric YACs.     

Spatial and Temporal variations of mangrove fish assemblages in Martinique (French West Indies)

A study of the mangrove fish fauna in a bay of Martinique Island (French West Indies) was carried out at different seasons during two consecutive years. fishes were sampled with specific hoop-nets in the coastal areas at 8 stations.A total of 87 species was collected in the bay. Most individuals were represented by small-size specimens and juveniles. The overall species richness varied according to the stations and the sampling periods. The biomass and number of individuals were variable according to the location but remained stable in time. A factor correspondence analysis and a hierarchical clustering with median links were used to follow the evolution of the stations in space and time. Two types of stations were differentiated: the stations characterized by the mangrove and those under the influence of seagrass beds. A seasonal cycle, opposing the dry periods to the others, was observed.Thus, it seems that the use of the mangrove habitat by the fishes is optimized through a complete reorganization of communities in terms of species composition whereas the overall number and biomass remain stable. This model remains valid even for the most constraining biota of the mangrove ecosystem inhabited by a small number of well adapted species.     

Stream-dwelling insects and extremely low frequency electromagnetic fields: a ten-year study

Changes in the structure of benthic insect communities at an experimental site and at a reference site in the Ford River, Michigan were monitored over a 10-year period to determine whether extremely low frequency electromagnetic fields (ELF) affected those communities. Five of 10 biotic parameters monitored are presented: taxon evenness (J), richness (S), numerical dominance of chironomids, and total insect mass. Data were separated into three seasons because coefficient of variation values were lower in the summer than in the spring and fall. Two-way ANOVA tests for the biotic variables were often significantly different between sites and among years, but the interaction terms were less frequently significant. Biotic parameters were regressed against stream discharge, water temperatures, years, and ELF cumulative ground field exposures. At the experimental site, discharge accounted for more variation than did water temperature or years for all biotic parameters except chironomid numerical dominance in the fall. Intervention analyses, using the B.A.C.I parametric or the R.I.A non-parametric showed significant differences in three of 15 cases; namely, for the highly varying chironomid numerical dominance values in the spring and fall and for the low varying total insect mass values in the summer. For those tests, the Before Impact period spanned April 1984 through May 1986. The After Impact period (full ELF power) spanned June 1989 through August 1993. Trend analysis for total insect mass at the experimental site in the summer showed discharge to be more important than water temperatures or ELF ground field exposures. Natural physical factors appear to be more important than the anthropogenic ELF fields in accounting for seasonal and yearly changes in the community.     

Glycan modification of a thermostable recombinant (1-3,1-4)-β-glucanase secreted fromSaccharomyces cerevisiae is determined by strain and culture conditions

High level biosynthesis and secretion of the thermostable hybrid (1-3,1-4)--glucanase H(A16-M) has been achieved inSaccharomyces cerevisiae by means of the yeast vacuolar endoprotease B promoter (PRB1_p) and theBacillus macerans (1-3,1-4)--glucanase signal peptide. The N-glycans present on the yeast-secreted H(A16-M), denoted H(A16-M)-Y, were released by endoglycosidase H, and identified by proton NMR spectroscopy to be a homologous series of Man_8-13GlcNAc₂, although only traces of Man₉GlcNAc₂ were found. Therefore, processing of N-glycans on H(A16-M)-Y is similar to that on homologous proteins. Most of the N-glycans (88%) were neutral while the remainder were charged due to phosphorylation. Site-directed mutagenesis of Asn to Gln in two of the N-glycosylation sequons, and subsequent analysis of the N-glycans on the yeast-secreted proteins together with analysis of the N-glycans from the individual sites of H(A16-M)-Y suggest the presence of steric hindrance to glycan modification by the glycans themselves. H(A16-M)-Y produced under control of either the yeast protease B or the yeast 3-phosphoglycerate kinase promoter, each in two differentSaccharomyces strains revealed a dependence of N-glycan profile on both strain and culture conditions. The extent of O-glycosylation was found to be nine mannose units per H(A16-M)-Y molecule. An attempt to identify the linkage-sites for the O-glycans by amino acid sequencing failed, suggesting non-stoichiometric or heterogeneous O-glycosylation. The possible modes in which N-glycans might contribute to resistance of H(A16-M)-Y to irreversible thermal denaturation are discussed with respect to structural information available for H(A16-M)-Y. Abbreviations: AMY,B. amyloliquefaciens (1-3,1-4)--glucanse; MAC,B. macerans (1-3,1-4)--glucanase H(A16-M), H(A36-M), H(A78-M),H(A107-M) and H(A152-M), hybrid (1-3,1-4)--glucanases containing 16, 36, 78, 107 and 152 N-terminal amino acids, respectively, derived from AMY with the remaining amino acids derived from MAC; similar enzyme abbreviations followed by Y, e.g. H(A16-M)-Y, denote the enzymes secreted from yeast cells; PCR, polymerase chain reaction; PGK_p, yeast 3-phosphoglycerate kinase promoter; PRB1_p, yeast protease B promoter; LB, Luria-Bertani medium; SC, minimal medium; CNBr, cyanogen bromide; Endo H_f, endoglycosidase H fusion protein; PNGase F, peptide:N-glycosidase F; HPAEC; high pH anion exchange chromatography; HVE, high voltage paper electrophoresis; CPY, yeast carboxypeptidase Y.