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PubMed1992

Unusual HLA-B alleles in two tribes of Brazilian Indians.

The Kaingang and Guarani are culturally and linguistically distinct tribes of southern Brazil. Like all Amerindian groups they show limited HLA polymorphism, which probably reflects the small founder populations that colonized America by overland migration from Asia 11,000-40,000 years ago. We find the nucleotide sequences of HLA-B alleles from the Kaingang and Guarani to be distinct from those characterized in caucasian, oriental and other populations. By comparison, the HLA-A and C alleles are familiar. These results and those reported in the accompanying paper on the Waorani of Ecuador reveal that a marked evolution of HLA-B has occurred since humans first entered South America. New alleles have been formed through recombination between pre-existing alleles, not by point mutation, giving rise to distinctive diversification of HLA-B in different South American Indian tribes.

Alleles↗
PubMed2000

Mutations in a new gene in Ellis-van Creveld syndrome and Weyers acrodental dysostosis.

Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive skeletal dysplasia characterized by short limbs, short ribs, postaxial polydactyly and dysplastic nails and teeth. Congenital cardiac defects, most commonly a defect of primary atrial septation producing a common atrium, occur in 60% of affected individuals. The disease was mapped to chromosome 4p16 in nine Amish subpedigrees and single pedigrees from Mexico, Ecuador and Brazil. Weyers acrodental dysostosis (MIM 193530), an autosomal dominant disorder with a similar but milder phenotype, has been mapped in a single pedigree to an area including the EvC critical region. We have identified a new gene (EVC), encoding a 992-amino-acid protein, that is mutated in individuals with EvC. We identified a splice-donor change in an Amish pedigree and six truncating mutations and a single amino acid deletion in seven pedigrees. The heterozygous carriers of these mutations did not manifest features of EvC. We found two heterozygous missense mutations associated with a phenotype, one in a man with Weyers acrodental dysostosis and another in a father and his daughter, who both have the heart defect characteristic of EvC and polydactyly, but not short stature. We suggest that EvC and Weyers acrodental dysostosis are allelic conditions.

Alternative Splicing↗
PubMed2004

Neutral locus heterozygosity, inbreeding, and survival in Darwin's ground finches (Geospiza fortis and G. scandens).

Comprehensive long-term studies of isolated populations provide valuable comparative data that may be used to evaluate different methods for quantifying the relationship between genetic diversity and fitness. Here, we report on data collected from large and well-characterized cohorts of the two numerically dominant species of Darwin's finches on Isla Daphne Major, Galápagos, Ecuador - Geospiza fortis and G. scandens. Multilocus microsatellite (SSR) genetic diversity estimates (heterozygosity and d2) and pedigree-based estimates of the inbreeding coefficient (f) were compared to each other and to two fitness components: lifespan and recruitment. In the larger sample of G. fortis, heterozygosity (H) was correlated with both fitness components, but no relationship was detected in the smaller sample of G. scandens. Analyses of the inbreeding coefficient detected highly significant relationships between f and recruitment, but no relationship between f and overall lifespan. The d2 statistic showed no relationship to either fitness component. When the two SSR-based estimators were compared to f, d2 was correlated with f in G. fortis in the predicted direction, while in G. scandens the relationship was positive. Multilocus heterozygosity was correlated with f in G. fortis but not in the G. scandens sample. A pedigree simulation demonstrated that the variation in true autozygosity can be large among individuals with the same level of inbreeding. This observation may supplement the interpretation of patterns relevant to the local (locus-specific) and general (genome-wide) effects hypotheses, which have been proposed to explain the mechanism responsible for associations between genetic diversity and fitness.

Alleles↗
PubMed2003

Traumatic cervical instability associated with cord oedema and temporary quadriparesis.

STUDY DESIGN: A case report of blunt cervical spine trauma associated with cord oedema at the C3/C4 level with temporary Frankel/American Spinal Injury Association Grade A quadriparesis and motion segment instability without evidence of associated bony lesions (spinal cord injury without radiological abnormality, SCIWORA lesion). OBJECTIVES: By means of a rare and illustrative case, the reader's attention is focused on eventual marked cervical motion segment instability in SCIWORA patients. SETTING: A department of Neurology in Quito, Ecuador and a department of Neurosurgery in Bern, Switzerland. METHOD: A 73-year-old man sustained blunt cervical spine trauma. After resolution of paraparesis, dynamic studies of the cervical spine revealed translational instability of C3 over C4. The patient underwent segment fusion by intervertebral cage insertion and plate fixation. RESULTS: The patient had recovered almost completely from tetraparesis under conservative treatment. The postoperative course was uneventful. Solid bony fusion of the C3/C4 motion segment was obtained. CONCLUSION: Despite normal cervical alignment, the lack of bony lesions and neurological recovery, magnetic resonance imaging and dynamic studies may reveal marked translational cervical motion segment instability requiring segment fusion in order to prevent ongoing damage of the spinal cord.

Aged↗
PubMed2001

Microsatellite analysis of medfly bioinfestations in California.

The Mediterranean fruit fly, Ceratitis capitata, is a destructive agricultural pest with a long history of invasion success. This pest has been affecting different regions of the United States for the past 30 years, but a number of studies of medfly bioinfestations has focused on the situation in California. Although some progress has been made in terms of establishing the origin of infestations, the overall status of this pest in this area remains controversial. Specifically, do flies captured over the years represent independent infestations or the persistence of a resident population? We present an effort to answer this question based on the use of multilocus genotyping. Ten microsatellite loci were used to analyse 109 medflies captured in several infestations within California between 1992 and 1998. Using these same markers, 242 medflies from regions of the world having 'established' populations of this pest including Hawaii, Guatemala, El Salvador, Ecuador, Brazil, Argentina and Peru, were also analysed. Although phylogenetic analysis, amova analysis, the IMMANC assignment test and geneclass exclusion test analysis suggest that some of the medflies captured in California are derived from independent invasion events, analysis of specimens from the Los Angeles basin provides support for the hypothesis that an endemic population, probably derived from Guatemala, has been established.

Agriculture↗
PubMed2003

Isolation of partial toxR gene of Vibrio harveyi and design of toxR-targeted PCR primers for species detection.

AIMS: To differentiate Vibrio harveyi from closely related Vibrio species by toxR sequence analysis and design primers for the specific detection of the shellfish pathogen. METHODS AND RESULTS: The partial toxR homologue from the shellfish pathogen V. harveyi was isolated by PCR using degenerate primers. The 578-bp toxR fragment from V. harveyi, that exhibited highest homology with partial toxR of V. parahaemolyticus (68%), is predicted to encode for a polypeptide with 192 amino acid residues. Alignment of the V. harveyi toxR nucleotide and deduced amino acid sequence with those from other Vibrio species revealed the presence of the fairly characteristic conserved transcription activation and transmembrane domain as well as the divergent membrane tether region that may be targeted for the development of species-specific oligonucleotide primers. Consequently, PCR primers that could amplify a 390-bp gene fragment in V. harveyi were designed by targeting portions of the V. harveyi toxR that display variability with toxR sequences from other Vibrio species. The 390-bp-amplicon was detected in all V. harveyi strains examined except in the nontarget bacteria and unexpectedly, in two shrimp-derived strains (VIB 391 and STD 3-101) from Thailand and Ecuador. Results show that strains exhibiting the 390-bp amplicon mostly belong to the same cluster based on previous amplified fragment length polymorphism data while strains which were previously unclustered or unclassified did not display the 390-bp PCR product. CONCLUSIONS: The toxR sequence variation could differentiate V. harveyi from closely related Vibrio species. A PCR protocol amplifying a 390-bp fragment of the V. harveyi toxR was established and could be useful in the specific and rapid detection of the species. SIGNIFICANCE AND IMPACT OF THE STUDY: The molecular approaches reported in this study could facilitate the early diagnosis and surveillance of luminous vibriosis in hatchery-reared fish and shellfish species through rapid identification and specific detection of causal agent.

Amino Acid Sequence↗
PubMed2003

Comparative phylogeography of short-tailed bats (Carollia: Phyllostomidae).

This is the first study of comparative phylogeography involving closely related species of Neotropical bats of the family Phyllostomidae. We compared patterns of geographical variation within the five species of fruit-eating bats currently recognized in the genus Carollia using the complete mitochondrial cytochrome-b gene. Our results suggest that the combined effect of the uplift of the Andes and the Panamanian land bridge has been as important for bats as for terrestrial mammals in shaping present-day biodiversity in the New World tropics. Species in this genus can be arranged in two highly supported clades, with a deep subdivision within each that corresponds well to differences across the Andes. We found three congruent phylogeographical patterns across species in this genus. First, the closer relationship between samples from western Ecuador and those from Central America, compared with populations east of the Andes in C. brevicauda, C. castanea and C. perspicillata. Second, the likelihood of a similar timing in South America for the arrival and diversification of C. brevicauda and C. perspicillata from their Central America ancestors. Third, the expansion of C. perspicillata and C. sowelli into northwestern Central America in the relatively recent past. Using a molecular clock, with rates ranging from 2.3 to 5% per 10(6) years, diversification within Carollia would have occurred over the last 1-4.5 Myr. These estimates agree well with the last rise of the Northern Andes and the Panama isthmus.

Animals↗
PubMed2003

History of tobacco and health.

Tobacco comes from plants that are native to the Americas around Peru and Ecuador,where it has been found since prehistoric times. It was brought back to Europe by early explorers where it was adopted by society and re-exported to the rest of the world as European colonization took place. Smoking tobacco in pipes of one sort or other gave way to handmade and then manufactured cigarettes, especially during the First World War. Smoking rates increased dramatically during the 20th century in developed countries until recently and rates are still increasing in underdeveloped countries. An epidemic of smoking-related diseases has followed the prevalence of smoking. Scientific knowledge of the harmful effects of active tobacco smoking has accumulated during the past 60 years since early descriptions of the increasing prevalence of lung cancer. The first epidemiological studies showing an association between smoking and lung cancer were published in 1950. In 1990 the US Surgeon General concluded that smoking was the most extensively documented cause of disease ever investigated but governments worldwide have been ambivalent and slow in taking action to reduce smoking. Tobacco smoking is now agreed to be a major cause of a vast number of diseases and other adverse effects. Since the 1980s passive smoking including exposure in utero has also been implicated as a significant cause of numerous diseases. In response, the tobacco industry has managed to forestall and prevent efforts to control this major health problem.

History, 15th Century↗
PubMed2005

Anatomy of Tunga trimamillata Pampiglione et al., 2002 (Insecta, Siphonaptera, Tungidae) and developmental phases of the gravid female.

This paper deals with some internal anatomical features observed in histological sections and freshly dissected mounts of Tunga trimamillata, a Siphonaptera recently discovered in Andean regions of Ecuador from several mammals, including man. It was possible to study in males and also non-gravid and gravid females, the location and anatomy of several organs not previously described for this species: the testes, epididymis, ganglia, Malpighian tubules, eyes, rectal ampulla with one of its pads and structures which could be interpreted as midgut diverticula, whose presence has not been recorded in the Siphonaptera. The process of neosomy in the female during pregnancy is illustrated by photographs of the consecutive developmental phases, taken at the stereomicroscope. Furthermore, some details of the exoskeleton, spermatheca during different phases of pregnancy of the gravid female and the presence of a foreign body (parasite?) within the haemocoel have been displayed in specimens cleared with Hoyer's medium.

Animals↗
PubMed2006

Ploidy level variability in South American fescues (festuca L., poaceae): use of flow cytometry in up to 5 1/2-year-old caryopses and herbarium specimens.

Ploidy levels and chromosome numbers for 24 species of Festuca L. from 29 sites in Bolivia, Colombia, Ecuador and Venezuela are given. The ploidy level of 22 species is reported for the first time. A higher proportion of tetraploids in northern South America and the high frequency of polyploids in the whole continent are documented. In combination with chromosome counts, ploidy level was determined using flow cytometry in 4- to 5 1/2 -year-old herbarium specimens and mature caryopses. Flow cytometric determination from seeds was more reliable than determination from herbarium specimens. In herbarium specimens, the youngest, fresh green leaves, still hidden in sheaths, seem to be most suitable for cytometric determination. In old, brownish leaves, or poorly preserved herbarium specimens, the degradation of DNA signal in flow histograms was documented. DNA content measured in seeds was always higher than that measured in herbarium specimens, which may be caused by the presence of different cytosolic compounds. Differences of about 15% in relative DNA content of F. sodiroana and F. vaginalis was found in simultaneous measurements in seeds.

DNA, Plant↗
PubMed1994

Studies on the anti-tumour, anti-bacterial, and wound-healing properties of dragon's blood.

Three in-vitro assays have been adopted to examine the cytotoxicity and anti-bacterial activity of the blood-red sap of Croton lechleri from Ecuador, and to examine its effect upon the proliferation of endothelial cells. The sap was found not to be cytotoxic. Several simple phenolic compounds and diterpenes showed a potent anti-bacterial activity. The sap has little effect upon the proliferation of endothelial cells, and no single active ingredient was identified. A mechanism for the wound-healing property of the sap has been proposed.

Animals↗
PubMed2003

Reduced risk of atopy among school-age children infected with geohelminth parasites in a rural area of the tropics.

BACKGROUND: Childhood infections might protect against the expression of atopy. Geohelminths are among the most prevalent infections of childhood and might contribute to the low prevalence of allergic disease reported from rural areas of the tropics. OBJECTIVE: We sought to establish whether geohelminth infections protect against atopy and to explore whether this protection is dependent on infection chronicity. METHODS: The risk of atopy (measured by means of allergen skin test reactivity) associated with active geohelminth infections (measured by means of the presence of eggs in stool samples) or with chronic geohelminth infections (measured by means of high levels [>/=3564 IU/mL] of total serum IgE or the presence of detectable anti-Ascaris lumbricoides IgG4 antibodies) was investigated in an analytic cross-sectional study conducted among school-age children attending rural schools in Pichincha Province in Ecuador. RESULTS: A total of 2865 children aged 5 to 19 years from 55 schools was examined. Active infection with any geohelminth and infections with A lumbricoides or Ancylostoma duodenale were associated with significant protective effects against allergen skin test reactivity. Children with the highest levels of total IgE or with anti-A lumbricoides IgG4 antibodies were protected against skin test reactivity also, and the protective effects of high IgE or anti-A lumbricoides IgG4 and or active geohelminth infections were statistically independent. CONCLUSION: Active infections with geohelminth parasites and the presence of serologic markers of chronic infections (high levels of total serum IgE or anti-A lumbricoides IgG4) are independent protective factors against allergen skin test reactivity among school-age children living in an endemic region of the rural tropics.

Adolescent↗
PubMed2007

Soil nutrients influence spatial distributions of tropical tree species.

The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (<10(4) km(2)) and regional scales. At local scales (<1 km(2)), however, habitat factors and species distributions show comparable spatial aggregation, making it difficult to disentangle the importance of niche and dispersal processes. In this article, we test soil resource-based niche assembly at a local scale, using species and soil nutrient distributions obtained at high spatial resolution in three diverse neotropical forest plots in Colombia (La Planada), Ecuador (Yasuni), and Panama (Barro Colorado Island). Using spatial distribution maps of >0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species.

Ecosystem↗
PubMed2001

Extreme morphological and ecological homoplasy in tropical salamanders.

Fossorial salamanders typically have elongate and attenuated heads and bodies, diminutive limbs, hands and feet, and extremely elongate tails. Batrachoseps from California, Lineatriton from eastern México, and Oedipina from southern México to Ecuador, all members of the family Plethodontidae, tribe Bolitoglossini, resemble one another in external morphology, which has evolved independently. Whereas Oedipina and Batrachoseps are elongate because there are more trunk vertebrae, a widespread homoplasy (parallelism) in salamanders, the genus Lineatriton is unique in having evolved convergently by an alternate "giraffe-neck" developmental program. Lineatriton has the same number of trunk vertebrae as related, nonelongated taxa, but individual trunk vertebrae are elongated. A robust phylogenetic hypothesis, based on sequences of three mtDNA genes, finds Lineatriton to be deeply nested within a clade characterized by generalized ecology and morphology. Lineatriton lineolus, the only currently recognized taxon in the genus, shows unanticipated genetic diversity. Surprisingly, geographically separated populations of L. lineolus are not monophyletic, but are sister taxa of different species of the morphologically generalized genus Pseudoeurycea. Lineatriton, long thought to be a unique monospecific lineage, is polyphyletic. Accordingly, the specialized morphology of Lineatriton displays homoplasy at two hierarchical levels: (i) with respect to other elongate lineages in the family (convergence), and (ii) within what is currently recognized as a single taxon (parallelism). These evolutionary events are of adaptive significance because to invade the lowland tropics salamanders must be either arboreal or fossorial; the repeated evolution of elongation and attenuation has led to multiple lowland invasions.

Animals↗
PubMed1995

Identification of presumed ancestral DNA sequences of phaseolin in Phaseolus vulgaris.

Common bean (Phaseolus vulgaris) consists of two major geographic gene pools, one distributed in Mexico, Central America, and Colombia and the other in the southern Andes (southern Peru, Bolivia, and Argentina). Amplification and sequencing of members of the multigene family coding for phaseolin, the major seed storage protein of the common bean, provide evidence for accumulation of tandem direct repeats in both introns and exons during evolution of the multigene family in this species. The presumed ancestral phaseolin sequences, without tandem repeats, were found in recently discovered but nearly extinct wild common bean populations of Ecuador and northern Peru that are intermediate between the two major gene pools of the species based on geographical and molecular arguments. Our results illustrate the usefulness of tandem direct repeats in establishing the polarity of DNA sequence divergence and therefore in proposing phylogenies.

Base Sequence↗
PubMed1996

Patterns of kinship in groups of free-living sperm whales (Physeter macrocephalus) revealed by multiple molecular genetic analyses.

Mature female sperm whales (Physeter macrocephalus) live in socially cohesive groups of 10-30, which include immature animals of both sexes, and within which there is communal care of the young. We examined kinship in such groups using analyses of microsatellite DNA, mitochondrial DNA sequence, and sex-linked markers on samples of sloughed skin collected noninvasively from animals in three groups off the coast of Ecuador. Social groups were defined through photographic identification of individuals. Each group contained about 26 members, mostly female (79%). Relatedness was greater within groups, as compared to between groups. Particular mitochondrial haplotypes were characteristic of groups, but all groups contained more than one haplotype. The data are generally consistent with each group being comprised of several matrillines from which males disperse at about the age of 6 years. There are indications of paternal relatedness among grouped individuals with different mitochondrial haplotypes, suggesting long-term associations between different matrilines.

Age Factors↗
PubMed2003

The hypnotic belay in alpine mountaineering: the use of self-hypnosis for the resolution of sports injuries and for performance enhancement.

The author, an experienced alpine mountaineer, sustained several traumatic climbing injuries over a two-year period. This article describes her multiple uses of self-hypnosis to deal with several challenges related to her returning to successful mountain climbing. She used self-hypnosis for physical healing and to enhance her motivation to resume climbing. While training for her next expedition, she successfully utilized self-hypnotic techniques to deal with acute stress and later post-traumatic symptoms that had emerged related to her climbing injuries. She describes her use of hypnotic ego-strengthening, mental rehearsal, age progression, and "Inner Strength" as well as active-alert trance states. Her successful summitting of Ecuador's Cotopaxi at 19,380 feet was facilitated by "The Hypnotic Belay" which permitted her to secure herself by self-hypnosis in addition to the rope used to secure climbers. In 1994, the author returned to the Cascade Mountains where she had been injured three years earlier and reached the summit of Mount Shuksan. This time she was secured by "The Hypnotic Belay".

Athletic Injuries↗
PubMed1991

Uptake of chloroquine by Onchocerca volvulus in vivo and in vitro.

Patients infected with Onchocerca volvulus in the Cayapa River focus in north-east Ecuador were given 500 mg chloroquine diphosphate (CQ) orally prior to nodulectomy. The concentrations of CQ were determined in parasite fragments and host tissue dissected from the nodules, in skin overlying the nodules, and in plasma at 3, 4, 7, and 24 hours after dosing. Onchocerca volvulus took up CQ rapidly, in some cases accumulating the drug to concentrations of over 600 pmol mg-1 worm tissue by three hours, and maintaining similar concentrations through 24 hours. These amounts were markedly higher than peak concentrations in plasma (3.16 pmol microliters-1) and in host tissues (78 pmol mgm-1) and skin (up to 93 pmol mg-1). In vitro uptake of CQ by females of O. volvulus was greater under alkaline conditions (pH 8.4) than at pH 6.8 and 7.4. Uptake reached equilibrium after one to two hours, with final concentrations being approximately 10 times lower than those reached in vivo. Inhibitory effects of chloroquine and its major metabolite desethylchloroquine on the motility of O. volvulus and other filariae have been observed previously in vitro; whether or not the drug had adverse effects on adult parasites in vivo was not determined in these experiments. However, the results illustrate the accessibility of O. volvulus to blood borne agents in vivo, and the potential importance of pharmacodynamic characteristics in the search for new macrofilaricidal agents.

Animals↗