The behavioural ecology of green monkeys (Cercopithecus sabaeus) at Mt. Assirik, Senegal

The aims of this study were to provide detailed information on the ecology of green monkeys in Senegal, to examine adaptive behavioural variation by comparing their behaviour with that of other populations of this widespread species-group (C. aethiops), and to use field-data to test hypotheses about adaptive strategies, particularly those concerned with how their foraging patterns changed with the seasonally variable availability and distribution of resources. Field-work was carried out at Mt. Assirik, in the Parc National du Niokolo-Koba, Senegal. The climate, vegetation, and fauna of the region were described. On most criteria, Mt. Assirik is vegetationally richer in density and diversity of species than two study-sites compared in Cameroon, and one in Kenya, where other populations of C. aethiops have been studied. The demographic structure of the population of green monkeys at Mt. Assirik was assessed. The mean size of groups was 19 monkeys, who lived at a comparatively low overall density of 4.4 per km2. This, the lowest density recorded for C. aethiops, is ascribed to the extensive areas of sparse, unsuitable habitat that constitute a large part of the vegetational mosaic of the region.A single group of green monkeys was studied in detail, over one complete annual cycle. Aspects of their feeding, ranging, activity-budgets, and territorial behaviour were recorded during 5-day sample-periods each month, in parallel with close monitoring of the changing composition, density, and distribution of important resources. The green monkeys' diet was omnivorous and diverse, including over 65 species of plants, many invertebrates, and some eggs and meat. Preference was given to fruits and flowers, although particular species were not selected; rather, these foods were eaten in proportion to their availability. Leaves, gum, seeds, and fungi were secondary choice foods. There was little overlap in the composition of the diet from month to month, indicating the strong seasonality of the environment. There was a fairly consistent intake of invertebrates each month. The monkeys spent between 35% and 55% of their time feeding. Diurnal rhythms of activity were strongly influenced by temperature: the monkeys stopped feeding and travelling when it was either too hot or too cold. On a finer time-scale, feeding was more closely synchronized between the monkeys when they fed on less common species. Several age and sex differences in feeding were found. In particular, females with very young infants fed less than other adults. No particular height-niche was occupied by the monkeys. The study group ranged over an area of 1.78 km2, the largest range recorded for any C. aethiops group. Their ranging patterns differed from month to month, and were significantly influenced by the availability and distribution of food, water, sleeping sites, and habitat-types, and by patterns of intergroup relations. Territorial behaviour itself was strongly influenced by the availability and distribution of key food sources, and the intensity of intergroup encounters varied accordingly. Many differences in patterns of feeding and ranging between populations of C. aethiops are related to the floristic composition of the vegetation, but comparisons were limited by lack of appropriate data on the availability and distribution of food at other sites. Data on the seasonally varied patterns of feeding, ranging, and activity-budgets, and changing patterns of resource availability, were drawn together to examine the adaptive strategies underlying the monkeys' behaviour. Several models in optimal foraging theory were tested. Time and energy spent in feeding and travelling increased as food-availability increased. Their choice of diet was optimal in that they were more selective when profitable food-items were common: higher proportions of the diet were given over to fruit and flowers when food-availability was high. In parallel with these strategies, a nutritive balance was maintained by consistent inclusion of at least some foliage and invertebrates in the diet, however much fruit was eaten

rRNA gene activity and control of expression mediated by methylation and imprinting during embryo development in wheat x rye hybrids

Ribosomal RNA genes originating from one parent are often suppressed in interspecific hybrids. We show that treatments during germination with the cytosine analogue 5-azacytidine stably reactivate the expression of the suppressed rRNA genes of rye origin in the wheat x rye amphiploid, triticale, by preventing methylation of sites in the rye rDNA. When 5-azacytidine is applied to embryos of triticale and wheat x rye F1 hybrids nine, or more, days after fertilization, rye rRNA gene expression is stably reactivated in the resulting seedling. Earlier treatments have no effect on rye rRNA gene expression, indicating that undermethylation of DNA early in embryo development is reversible. After 9 days, the methylation status of rRNA genes in maintained throughout development. Since the change in expression follows a methylation change at particular restriction-enzyme sites, the data establish a clear correlation between gene activity and methylation in plants

Symptoms, stenosis and carotid plaque morphology. Is plaque morphology relevant?

Objectives:To study the relationship between carotid plaque morphology and the degree of stenosis on Duplex ultrasonography and symptoms.Design:Prospective open clinical study.Methods:2590 patients with 5180 carotid arteries were scanned, 4560 were initially analysed in terms of symptoms but 54 were excluded, leaving a total of 4258.Results:Localising symptoms were present with respect to 1342 vessels (29.4%). Two-thirds of symptomatic patients had normal carotid arteries. Tight stenosis (80–99%) was more likely to be associated with symptoms than low-grade (20–79%) stenosis (x2=28.0, p < 0.0001). Plaque type was identified in 1558 bifurcations (36.6%). Heterogeneous type I & II plaques accounted for one third of plaques. There was a relationship between plaque morphology and degree of stenosis. At < 20% stenosis only 4.4% of plaques were heterogeneous whereas at 80–99% stenosis 84.5% of plaques were heterogeneous. Amaurosis fugax was the only symptom that had any association with a particular plaque morphology. Seventy-two percent of plaques associated with this symptom were heterogeneous in nature.Conclusions:Carotid plaque morphology and degree of internal carotid stenosis are mutually dependent factors and both reflect the severity of atherosclerotic disease. Plaque morphology does not add to the sensitivity of stenosis in predicting the presence of symptoms

Effects of temperature on responses to anoxia and oxygen reperfusion in Drosophila melanogaster

Insects in general, and Drosophila in particular, are much more capable of surviving anoxia than vertebrates, and the mechanisms involved are of considerable biomedical and ecological interest. Temperature is likely to strongly affect both the rates of damage occurring in anoxia and the recovery processes in normoxia, but as yet there is no information on the effect of this crucial variable on recovery rates from anoxia in any animal. We studied the effects of temperature, and thus indirectly of metabolic flux rates, on survival and recovery times of individual male Drosophila melanogaster following anoxia and O2 reperfusion. Individual flies were reared at 25° and exposed to an anoxic period of 7.5, 25, 42.5 or 60?min at 20, 25 or 30°. Before, during and after anoxic exposure the flies' metabolic rates (MRs), rates of water loss and activity indices were recorded. Temperature strongly affected the MR of the flies, with a Q10 of 2.21. Temperature did not affect the slope of the relationship between time to recovery and duration of anoxic exposure, suggesting that thermal effects on damage and repair rates were similar. However, the intercept of that relationship was significantly lower (i.e. recovery was most rapid) at 25°, which was the rearing temperature. When temperatures during exposure to anoxia and during recovery were switched, recovery times matched those predicted from a model in which the accumulation and clearance of metabolic end-products share a similar dependence on temperature. ©2011. Published by The Company of Biologists Ltd.Fil:Schilman, P.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Evaluating the Potential of Using 5-Azacytidine as an Epimutagen

A number of early flowering lines were induced when 5-azacytidine was applied to germinating flax (Linum usitatissimum L.) seed. The genetics of these lines indicate that the induced changes are epigenetic and probably result from demethylation of the genomic DNA at loci that affect flowering age. Although the growth and development of three stable early flowering lines are altered and the percentage of filled seed was reduced in all three lines compared with controls, measures of seed productivity demonstrated that harvest index was unaffected in two of the lines. In the third, harvest index was lower than normal and both seed set per capsule and seed mass per 100 seed were reduced. Furthermore, six generations after induction this line began to display relatively high levels of polyembryony. The late appearance of this twinning and other aspects related to working with lines induced by 5-azacytidine and using 5-azacytidine as an epimutagen are discussed

Role of anion size, magnetic moment, and disorder on the properties of the organic conductor kappa-(BETS)_2Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}

Shubnikov-de Haas and angular dependent magnetoresistance oscillations have been used to explore the role of anion size, magnetic moment, and disorder in the organic conductors kappa-(BETS)_2GaBr_{4} and kappa-(BETS)_2FeCl_{2}_Br_{2} in the isomorphic class kappa-(BETS)_2Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}. The results, combined with previous work, show correlations between the anion composition (Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}) and the superconducting transition temperature, effective mass, Fermi surface topology, and the mean free path.Comment: 5 pages, 6 figure

Integration of Banana Streak Badnavirus into theMusaGenome: Molecular and Cytogenetic Evidence

AbstractBreeding and tissue culture of certain cultivars of bananas (Musa) have led to high levels of banana streak badnavirus (BSV) infection in progeny from symptomless parents. BSV DNA hybridized to genomic DNA of one such parent, Obino l'Ewai, suggesting integration of viral sequences. Sequencing of clones of Obino l'Ewai genomic DNA revealed an interface between BSV andMusasequences and a complex BSV integrant.In situhybridization revealed two different BSV sequence locations in Obino l'Ewai chromosomes and a complex arrangement of BSV andMusasequences was shown by probing stretched DNA fibers. This is the first report of integrated sequences that possibly lead to a plant pararetrovirus episomal infection by a mechanism differing markedly from animal retroviral systems

The nature and organization of satellite DNAs in Petunia hybrida, related, and ancestral genomes

IntroductionThe garden petunia, Petunia hybrida (Solanaceae) is a fertile, diploid, annual hybrid species (2n=14) originating from P. axillaris and P. inflata 200 years ago. To understand the recent evolution of the P. hybrida genome, we examined tandemly repeated or satellite sequences using bioinformatic and molecular cytogenetic analysis.MethodsRaw reads from available genomic assemblies and survey sequences of P. axillaris N (PaxiN), P. inflata S6, (PinfS6), P. hybrida (PhybR27) and the here sequenced P. parodii S7 (PparS7) were used for graph and k-mer based cluster analysis of TAREAN and RepeatExplorer. Analysis of repeat specific monomer lengths and sequence heterogeneity of the major tandem repeat families with more than 0.01% genome proportion were complemented by fluorescent in situ hybridization (FISH) using consensus sequences as probes to chromosomes of all four species.ResultsSeven repeat families, PSAT1, PSAT3, PSAT4, PSAT5 PSAT6, PSAT7 and PSAT8, shared high consensus sequence similarity and organisation between the four genomes. Additionally, many degenerate copies were present. FISH in P. hybrida and in the three wild petunias confirmed the bioinformatics data and gave corresponding signals on all or some chromosomes. PSAT1 is located at the ends of all chromosomes except the 45S rDNA bearing short arms of chromosomes II and III, and we classify it as a telomere associated sequence (TAS). It is the most abundant satellite repeat with over 300,000 copies, 0.2% of the genomes. PSAT3 and the variant PSAT7 are located adjacent to the centromere or mid-arm of one to three chromosome pairs. PSAT5 has a strong signal at the end of the short arm of chromosome III in P. axillaris and P.inflata, while in P. hybrida additional interstitial sites were present. PSAT6 is located at the centromeres of chromosomes II and III. PSAT4 and PSAT8 were found with only short arrays.DiscussionThese results demonstrate that (i) repeat families occupy distinct niches within chromosomes, (ii) they differ in the copy number, cluster organization and homogenization events, and that (iii) the recent genome hybridization in breeding P. hybrida preserved the chromosomal position of repeats but affected the copy number of repetitive DNA

Localized f electrons in CexLa1-xRhIn5: dHvA Measurements

Measurements of the de Haas-van Alphen effect in CexLa1-xRhIn5 reveal that the Ce 4f electrons remain localized for all x, with the mass enhancement and progressive loss of one spin from the de Haas-van Alphen signal resulting from spin fluctuation effects. This behavior may be typical of antiferromagnetic heavy fermion compounds, inspite of the fact that the 4f electron localization in CeRhIn5 is driven, in part, by a spin-density wave instability.Comment: 4 pages, 4 figures, submitted to PR