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PubMed2006

The role of group size and environmental factors on survival in a cooperatively breeding tropical passerine.

1. Variation in survival, a major determinant of fitness, may be caused by individual or environmental characteristics. Furthermore, interactions between individuals may influence survival through the negative feedback effects of density dependence. Compared to species in temperate regions, we have little knowledge about population processes and variation in fitness in tropical bird species. 2. To investigate whether variation in survival could be explained by population size or climatic variables we used capture-recapture models in conjunction with a long-term data set from an island population of the territorial, cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). The lack of migration out of the study population means that our results are not confounded by dispersal. 3. Annual survival was high, both for adults (84%) and juveniles (61%), and did not differ between the sexes. Although there was significant variation in survival between years, this variation could not be explained by overall population size or weather variables. 4. For territorial species, resource competition will work mainly on a local scale. The size of a territory and number of individuals living in it will therefore be a more appropriate measure of density than overall population density. Consequently, both an index of territory quality per individual (food availability) and local density, measured as group size, were included as individual covariates in our analyses. 5. Local density had a negative effect on survival; birds living in larger groups had lower survival probabilities than those living in small groups. Food availability did not affect survival. 6. Our study shows that, in a territorial species, although density-dependent effects might not be detectable at the population level they can be detected at the individual territory level - the scale at which individuals compete. These results will help to provide a better understanding of the small-scale processes involved in the dynamics of a population in general, but in particular in tropical species living in relatively stable environments.

Animals↗
PubMed2006

Towards unbiased parentage assignment: combining genetic, behavioural and spatial data in a Bayesian framework.

Inferring the parentage of a sample of individuals is often a prerequisite for many types of analysis in molecular ecology, evolutionary biology and quantitative genetics. In all but a few cases, the method of parentage assignment is divorced from the methods used to estimate the parameters of primary interest, such as mate choice or heritability. Here we present a Bayesian approach that simultaneously estimates the parentage of a sample of individuals and a wide range of population-level parameters in which we are interested. We show that joint estimation of parentage and population-level parameters increases the power of parentage assignment, reduces bias in parameter estimation, and accurately evaluates uncertainty in both. We illustrate the method by analysing a number of simulated test data sets, and through a re-analysis of parentage in the Seychelles warbler, Acrocephalus sechellensis. A combination of behavioural, spatial and genetic data are used in the analyses and, importantly, the method does not require strong prior information about the relationship between nongenetic data and parentage.

Animals↗
PubMed2001

Amphibians as indicators of early tertiary "out-of-India" dispersal of vertebrates.

Sixty-five million years ago, massive volcanism produced on the India-Seychelles landmass the largest continental lava deposit (Deccan Traps) of the past 200 million years. Using a molecular clock-independent approach for inferring dating information from molecular phylogenies, we show that multiple lineages of frogs survived Deccan Traps volcanism after millions of years of isolation on drifting India. The collision between the Indian and Eurasian plates was followed by wide dispersal of several of these lineages. This "out-of-India" scenario reveals a zoogeographical pattern that might reconcile paleontological and molecular data in other vertebrate groups.

Africa↗
PubMed2004

PCR analysis of the distribution of unicellular cyanobacterial diazotrophs in the Arabian Sea.

An oligonucleotide primer, NITRO821R, targeting the 16S rRNA gene of unicellular cyanobacterial N2 fixers was developed based on newly derived sequences from Crocosphaera sp. strain WH 8501 and Cyanothece sp. strains WH 8902 and WH 8904 as well as several previously described sequences of Cyanothece sp. and sequences of intracellular cyanobacterial symbionts of the marine diatom Climacodium frauenfeldianum. This oligonucleotide is specific for the targeted organisms, which represent a well-defined phylogenetic lineage, and can detect as few as 50 cells in a standard PCR when it is used as a reverse primer together with the cyanobacterium- and plastid-specific forward primer CYA359F (U. Nubel, F. Garcia-Pichel, and G. Muyzer, Appl. Environ. Microbiol. 63:3327-3332, 1997). Use of this primer pair in the PCR allowed analysis of the distribution of marine unicellular cyanobacterial diazotrophs along a transect following the 67 degrees E meridian from Victoria, Seychelles, to Muscat, Oman (0.5 degrees S to 26 degrees N) in the Arabian Sea. These organisms were found to be preferentially located in warm (>29 degrees C) oligotrophic subsurface waters between 0 and 7 degrees N, but they were also found at a station north of Oman at 26 degrees N, 56 degrees 35'E, where similar water column conditions prevailed. Slightly cooler oligotrophic waters (<29 degrees C) did not contain these organisms or the numbers were considerably reduced, suggesting that temperature is a key factor in dictating the abundance of this unicellular cyanobacterial diazotroph lineage in marine environments.

Base Sequence↗
PubMedDate not supplied

[New steroid glycosides from the starfish Fromia milleporella].

Two new steroid glycosides from the starfish Fromia milleporella collected in the Seychelles were isolated and characterized: milleporoside A, (20R, 24R)-29-O-[3-O-methyl-beta-D-xylopyranosyl-(1-->4)-3-O-methyl-beta-D-xylopyranosyl]-24-ethyl-5alpha-cholestane-3beta,4beta,6alpha,8,15beta,16beta,29-heptaol, and milleporoside B, (20R, 24R)-(22E)-28-O-[3-O-methyl-beta-D-xylopyranosyl-(1-->4)-3-O-methyl-beta-D-xylopyranosyl]-24-methyl-5alpha-cholest-22-ene-3beta,4beta,6alpha,8,15beta,16beta,28-heptaol. The structures of the glycosides were determined from their spectra and a comparison with spectral characteristics of known compounds. These compounds exhibit a moderate cytostatic activity toward the embryos of the sea urchin Strongylocentrotus intermedius.

Animals↗
PubMed1978

Viral infections in travellers from tropical Africa.

Examination of sera from 86 travellers to Britain from tropical Africa disclosed evidence of past infection with 10 identifiable viruses, of which the most important were O'nyong-nyong, dengue, chikungunya, and Ntaya. The findings indicate that infection with O'nyong-nyong may be acquired sporadically in Nigeria, Ghana, and Sierra Leone, where it has not previously been identified. Chikungunya infection had not been recorded in West Africa other than Nigeria and Senegal. Patients from Sierra Leone and contiguous Liberia had antibodies to this infection. An outbread of dengue fever in the Seychelles in early 1977 was confirmed. Ntaya virus, though known in Uganda, Cameroon, and Zaire, appears also to be transmitted in Kenya, Nigeria, and Zambia. Clinical studies indicated that chikungunya infection may present with alimentary features, possibly with jaundice. The clinical features of Ntaya infection may include kizarre neurological manifestations in addition to fever. The absence of Lassa antibodies among these travellers suggested that this infection is not a common hazard among such persons.

Adult↗
PubMed1998

Knowledge, attitudes, and practices on hypertension in a country in epidemiological transition.

Assessment of knowledge, attitudes, and practices (KAP) is a crucial element of hypertension control, but little information is available from developing countries where hypertension has lately been recognized as a major health problem. Therefore, we examined KAP on hypertension in a random sample of 1067 adults aged 25 to 64 years from the Seychelles Islands (Indian Ocean). KAP were assessed from an administered structured questionnaire. The age-standardized prevalence of hypertension (screening blood pressure [BP] > or = 160/95 mm Hg or taking antihypertensive medication) was 36% in men and 25% in women aged 25 to 64 years. Among hypertensive persons, 50% were aware of the condition, 34% were treated, and 10% had controlled BP (ie, BP <160/95 mm Hg). Most persons, whether nonhypertensive, unaware hypertensive, or aware hypertensive, had good basic knowledge related to hypertension determinants and consequences, possibly an effect of a nationwide cardiovascular disease prevention program over the last years. However, favorable outcome expectation, positive attitudes, and appropriate practices for hypertension and relevant healthy lifestyles were found in smaller proportions of participants, with little difference between aware hypertensives, unaware hypertensives, and nonhypertensives. Furthermore, hypertensive persons with other concurrent cardiovascular risk factors affecting the overall heart risk knew well the detrimental effects of these other factors but reported making little actual change to control them (particularly regarding overweight and sedentary habits). These data point to the need to maximize the efficiency of hypertension prevention and control programs so that delay in achieving effective hypertension control is minimized in countries experiencing recent emergence of hypertension as a major public health problem.

Adult↗
PubMed2000

Performance of classic electrocardiographic criteria for left ventricular hypertrophy in an African population.

ECG criteria for left ventricular hypertrophy (LVH) have been almost exclusively elaborated and calibrated in white populations. Because several interethnic differences in ECG characteristics have been found, the applicability of these criteria to African individuals remains to be demonstrated. We therefore investigated the performance of classic ECG criteria for LVH detection in an African population. Digitized 12-lead ECG tracings were obtained from 334 African individuals randomly selected from the general population of the Republic of Seychelles (Indian Ocean). Left ventricular mass was calculated with M-mode echocardiography and indexed to body height. LVH was defined by taking the 95th percentile of body height-indexed LVM values in a reference subgroup. In the entire study sample, 16 men and 15 women (prevalence 9.3%) were finally declared to have LVH, of whom 9 were of the reference subgroup. Sensitivity, specificity, accuracy, and positive and negative predictive values for LVH were calculated for 9 classic ECG criteria, and receiver operating characteristic curves were computed. We also generated a new composite time-voltage criterion with stepwise multiple linear regression: weighted time-voltage criterion=(0.2366R(aVL)+0.0551R(V5)+0.0785S(V3)+ 0.2993T(V1))xQRS duration. The Sokolow-Lyon criterion reached the highest sensitivity (61%) and the R(aVL) voltage criterion reached the highest specificity (97%) when evaluated at their traditional partition value. However, at a fixed specificity of 95%, the sensitivity of these 10 criteria ranged from 16% to 32%. Best accuracy was obtained with the R(aVL) voltage criterion and the new composite time-voltage criterion (89% for both). Positive and negative predictive values varied considerably depending on the concomitant presence of 3 clinical risk factors for LVH (hypertension, age >/=50 years, overweight). Median positive and negative predictive values of the 10 ECG criteria were 15% and 95%, respectively, for subjects with none or 1 of these risk factors compared with 63% and 76% for subjects with all of them. In conclusion, the performance of classic ECG criteria for LVH detection was largely disparate and appeared to be lower in this population of East African origin than in white subjects. A newly generated composite time-voltage criterion might provide improved performance. The predictive value of ECG criteria for LVH was considerably enhanced with the integration of information on concomitant clinical risk factors for LVH.

Adult↗
PubMed2006

Comprehensive molecular phylogeny of the sub-family Dipterocarpoideae (Dipterocarpaceae) based on chloroplast DNA sequences.

Dipterocarpoideae, the largest sub-family of well-known plant family Dipterocarpaceae, dominates in South Asian rain forests. Although several previous studies addressed the phylogeny of the Dipterocarpaceae family, relationships among many of its genera from the Dipterocarpoideae sub-family are still not well understood. In particular, little is known about the relationships of the genera Vateriopsis, Stemonoporus, Vateria and inconsistence remains between phylogenetic results and taxonomic classifications of Shorea and Hopea species. We studied molecular phylogeny of the sub-family Dipterocarpoideae using the trnL-trnF spacer, trnL intron and the matK gene sequences of chloroplast DNA (cpDNA). This study is the first comprehensive phylogeny reconstruction for the sub-family Dipterocarpoideae based on cpDNA, as it includes most genera (14) and a large number of species (79) with most species endemic to Sri Lanka, as well as one species from Seychelles and one species from the genus Monotes from Madagascar. Phylogenetic trees were constructed using the Neighbor Joining (NJ) and Maximum Likelihood (ML) methods using combined set of sequences including all three cpDNA regions. The topologies of the NJ and ML trees were to a certain extent, consistent with the current taxonomy of Dipterocarpoideae based on morphology and with previous molecular phylogenies based on cpDNA. Furthermore, our results provided new evidence regarding the relationships of the following genera: Vateriopsis and Stemonoporus and about the validity of the previous morphology based classifications of Shorea species. In addition, the topology of our trees was consistent with the classification of Shorea species proposed by Maury (1978), Maury-Lechon (1979) and Symington (1943). Finally, our results provided evidence for the affinity of the genus Monotes to Asian Dipterocarpoideae rather than to Tiliaceae and indicated that it is a good candidate for outgroup species for future studies of the former sub-family.

Chloroplasts↗
PubMed2001

Prenatal exposure of the northern Québec Inuit infants to environmental contaminants.

The Inuit population residing in Nunavik (northern Québec, Canada) relies on species from the marine food web for subsistence and is therefore exposed to high doses of environmental contaminants such as polychlorinated biphenyls and methylmercury and to a lesser extent lead. In view of the neurotoxic properties of these substances following developmental exposure, we initiated a study on infant development in this remote coastal population. Here we report the magnitude of prenatal exposure to these contaminants and to selective nutrients in Inuit mothers and their newborns who were recruited on the Hudson Bay coast. We conducted interviews during the women's pregnancies and at 1 and 11 months postpartum and collected biological samples for mercury, lead, polychlorinated biphenyls (PCBs), and chlorinated pesticides analyses as well as selenium and N-3 polyunsaturated fatty acids (n3-PUFA). Cord blood, maternal blood, and maternal hair mercury concentrations averaged 18.5 microg/L, 10.4 microg/L, and 3.7 microg/g, respectively, and are similar to those found in the Faroe Islands but lower than those documented in the Seychelles Islands and New Zealand cohorts. Concentrations of PCB congener 153 averaged 86.9, 105.3, and 131.6 microg/kg (lipids) in cord plasma, maternal plasma, and maternal milk, respectively; prenatal exposure to PCBs in the Nunavik cohort is similar to that reported in the Dutch but much lower than those in other Arctic cohorts. Levels of n3-PUFA in plasma phospholipids and selenium in blood are relatively high. The relatively low correlations observed between organochlorine and methylmercury concentrations may make it easier to identify the specific developmental deficits attributable to each toxicant. Similarly, the weak correlations noted between environmental contaminants and nutrients will facilitate the documentation of possible protective effects afforded by either n3-PUFA or selenium against neurotoxic contaminants.

Adult↗
PubMed2006

Genome microevolution of chikungunya viruses causing the Indian Ocean outbreak.

BACKGROUND: A chikungunya virus outbreak of unprecedented magnitude is currently ongoing in Indian Ocean territories. In Réunion Island, this alphavirus has already infected about one-third of the human population. The main clinical symptom of the disease is a painful and invalidating poly-arthralgia. Besides the arthralgic form, 123 patients with a confirmed chikungunya infection have developed severe clinical signs, i.e., neurological signs or fulminant hepatitis. METHODS AND FINDINGS: We report the nearly complete genome sequence of six selected viral isolates (isolated from five sera and one cerebrospinal fluid), along with partial sequences of glycoprotein E1 from a total of 127 patients from Réunion, Seychelles, Mauritius, Madagascar, and Mayotte islands. Our results indicate that the outbreak was initiated by a strain related to East-African isolates, from which viral variants have evolved following a traceable microevolution history. Unique molecular features of the outbreak isolates were identified. Notably, in the region coding for the non-structural proteins, ten amino acid changes were found, four of which were located in alphavirus-conserved positions of nsP2 (which contains helicase, protease, and RNA triphosphatase activities) and of the polymerase nsP4. The sole isolate obtained from the cerebrospinal fluid showed unique changes in nsP1 (T301I), nsP2 (Y642N), and nsP3 (E460 deletion), not obtained from isolates from sera. In the structural proteins region, two noteworthy changes (A226V and D284E) were observed in the membrane fusion glycoprotein E1. Homology 3D modelling allowed mapping of these two changes to regions that are important for membrane fusion and virion assembly. Change E1-A226V was absent in the initial strains but was observed in >90% of subsequent viral sequences from Réunion, denoting evolutionary success possibly due to adaptation to the mosquito vector. CONCLUSIONS: The unique molecular features of the analyzed Indian Ocean isolates of chikungunya virus demonstrate their high evolutionary potential and suggest possible clues for understanding the atypical magnitude and virulence of this outbreak.

Alphavirus Infections↗
PubMed2005

Organization of the sex-ratio meiotic drive region in Drosophila simulans.

Sex-ratio meiotic drive is the preferential transmission of the X chromosome by XY males, which occurs in several Drosophila species and results in female-biased progeny. Although the trait has long been known to exist, its molecular basis remains completely unknown. Here we report a fine-mapping experiment designed to characterize the major drive locus on a sex-ratio X chromosome of Drosophila simulans originating from the Seychelles (XSR6). This primary locus was found to contain two interacting elements at least, both of which are required for drive expression. One of them was genetically tracked to a tandem duplication containing six annotated genes (Trf2, CG32712, CG12125, CG1440, CG12123, org-1), and the other to a candidate region located approximately 110 kb away and spanning seven annotated genes. RT-PCR showed that all but two of these genes were expressed in the testis of both sex-ratio and standard males. In situ hybridization to polytene chromosomes revealed a complete association of the duplication with the sex-ratio trait in random samples of X chromosomes from Madagascar and Reunion.

Animals↗
PubMed2004

Signature of selective sweep associated with the evolution of sex-ratio drive in Drosophila simulans.

In several Drosophila species, the XY Mendelian ratio is disturbed by X-linked segregation distorters (sex-ratio drive). We used a collection of recombinants between a nondistorting chromosome and a distorting X chromosome originating from the Seychelles to map a candidate sex-ratio region in Drosophila simulans using molecular biallelic markers. Our data were compatible with the presence of a sex-ratio locus in the 7F cytological region. Using sequence polymorphism at the Nrg locus, we showed that sex-ratio has induced a strong selective sweep in populations from Madagascar and Réunion, where distorting chromosomes are close to a 50% frequency. The complete association between the marker and the sex-ratio phenotype and the near absence of mutations and recombination in the studied fragment after the sweep event indicate that this event is recent. Examples of selective sweeps are increasingly reported in a number of genomes. This case identifies the causal selective force. It illustrates that all selective sweeps are not necessarily indicative of an increase in the average fitness of populations.

Alleles↗
PubMed1998

Drugs for STD management in developing countries: choice, procurement, cost, and financing.

OBJECTIVES: (i) To compare acquisition costs of drugs between countries to treat one standardised STD episode. (ii) To explain variations, treatment protocols, purchasing policies, procurement systems, and sources of financing. METHODS: National STD guidelines, purchasing mechanisms, and drug acquisition costs from 15 countries were compiled, using information from ministries of health and European Commissions headquarters. Prices were converted in European currency unit (ecu). Acquisition costs per episode were calculated for the four main STD syndromes--urethral discharge, vaginal discharge, lower abdominal pain in women, and genital ulcer disease (GUD). To compare costs in different countries the relative distribution of the four main STD syndromes was calculated. RESULTS: Treatment protocols. All 15 countries recommended treatment for urethral discharge with drugs effective against Neisseria gonorrhoeae and Chlamydia trachomatis. For vaginal discharge two patterns emerged. In 11 countries women with vaginal discharge were divided into high risk of STDs and low risk of STDs. Women at low risk were treated for candidiasis, trichomoniasis, and bacterial vaginosis and those at high risk were also treated for N gonorrhoeae and C trachomatis. Guidelines for abdominal pain all included treatment for N gonorrhoeae, C trachomatis, and anaerobic infections. All countries except the Philippines recommended treating GUD with drugs effective against chancroid and syphilis. Costs per episode. Acquisition costs per episode varied from 0.40 ecu to 7.89 ecu with wide variations. The standardised acquisition cost of STD drugs for the public sector varied between 0.54 ecu in Tanzania and 5.80 ecu in Swaziland. The choice of drugs was the main factor explaining this difference. In countries which only use generic drugs, acquisition costs were lower (between 0.54 ecu and 1.07 ecu). However, important variations exist between countries which use similar treatment protocols (for example, 2.54 ecu in Namibia, 5.80 ecu in Swaziland). These variations are mainly explained by differences in procurement methods. Acquisition costs for peripheral public services are higher than at central level (for example, 0.89 ecu versus 0.54 ecu in Tanzania) as a result of mark ups for transport, handling, and inflation. Acquisition cost of drugs per standardised STD episode for patients through private pharmacies may be as high as 11.93 ecu in Senegal. This is more than 10 times the acquisition cost for public sector at central level in this country (of 1.04 ecu) and is mainly due to the fact that drugs in private pharmacies are branded drugs, which are imported at a high price, taxes, and mark ups in the distribution chain. In 11 of the 15 countries studied, effective STD drugs are now available through public services, in at least in a part of the country. In Botswana, Ghana, Ivory Coast, Mauritania, Lesotho, Namibia, Senegal, Seychelles, and Swaziland these drugs are supplied throughout the country within the existing essential drug programme and financed by the government budget or through a revolving fund for drugs. In Tanzania and Mozambique, all STD drugs in the public sector are funded through donor support. In Nepal recommended STD drugs are widely available at low cost through private outlets. CONCLUSIONS: Reducing antimicrobial susceptibility of N gonorrhoeae and Haemophilus ducreyi is a continuous threat for sustainable STD drug supply as alternative patented drugs are more expensive. If patented STD drugs are required drug cost may be minimised by selecting the most appropriate management protocols and by improving procurement. Moreover, recent studies have confirmed the continued susceptibility of N gonorrhoeae to low cost generic drugs in some countries (Mozambique, Tanzania, and Senegal). Even under these circumstances, continued donor support will be needed for the poorest countries to ensure the availability of effective STD management as an esse

Anti-Infective Agents↗
PubMed2000

Evaluation of techniques for assessing neurobehavioral development in children.

A battery of tests has been designed to explore functional disabilities in children 10-12 years of age arising from adverse conditions during early development. At these ages, it becomes possible to use more complex and challenging tests than those typically used at earlier ages. Although the battery was prompted originally by questions arising from methylmercury exposure, it was also designed for applicability to neurotoxicant exposures arising from pesticides, solvents, persistent organic pollutants such as PCBs and dioxins, other metals, and nutrient excesses and deficiencies as well. The test battery includes the following categories: (1) neuropsychological tests with established psychometric properties not widely exploited in studies of developmental neurotoxicity; (2) electrophysiological and behavioral tests of sensory functioning spanning a broader range of indices than those used generally in studies of neuropsychological development; and (3) adaptations of performance tasks used previously only in animals. The battery was developed in Rochester, New York, and then field-tested on a group of 61 children in the Republic of the Seychelles, where the Ministry of Health had established the Child Development Center. Our findings suggest a number of tests and procedures with the potential for inclusion in test batteries aimed at the exploration of adverse neurodevelopmental effects.

Adolescent↗
PubMed2002

Aquatic antagonists: Catalaphyllia jardinei sting.

Catalaphyllia jardinei is a blue-green soft coral whose red-violet tipped tentacles have made it a very colorful, popular animal prized by amateur aquarists (Figure 1). Its normal habitat is the Indo-Pacific area from Seychelles through Vanuatu and from Northern Australia to Southern Japan. It is regarded as mildly venomous. However, to our knowledge, no reports exist on its sting's effects on man.

Anthozoa↗
PubMedDate not supplied

[Ciguatera in the Maldive Islands].

In the Maldives archipelago, constituted of coral islands, where pollution is practically non-existent and where fish is the staple food of the inhabitants, ciguatera is almost unknown. The authors compares these findings with those observed in the Seychelles islands, where pollution seems to be relatively significant and ciguatera very rare. He thinks that pollution can only play a very slight part in the etiology of this intoxication.

Animals↗
PubMed1998

[Identification of Chinese drug sea coconut].

Sea Coconut is the seed of Lodoicea maldivica Persoon, palmae. It is one species in the Seychelles Islands, Africa. The drug is yellow-white in colour, slice-shaped, 12 cm in length and 4 cm in breadth. Seed-coat cell circular in shape. Under seed-coat, the cells are elliptic, and stone cells are rectangle with thick wall and large pit. Endosperm cell elongate with thick wall and large pits, the end of pits enlarge as a pearl.

Arecaceae↗