bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insecticide resistance spectra and resistance mechanisms in populations of Japanese encephalitis vector mosquitoes, Culex tritaeniorhynchus and Cx. gelidus, in Sri Lanka
Authors: Karunaratne S. H. P. P. , Hemingway J. 
Published: March 2003

Summary Culex tritaeniorhynchus Giles and Cx. gelidus Theobald (Diptera: Culicidae), both vectors of Japanese encephalitis, were collected in 1984 and 1998 from two disease endemic localities in Sri Lanka: Anaradhapura and Kandy. Using wild‐caught adult mosquitoes from light traps, log dosage‐probit mortality curves for insecticide bioassays were obtained for three insecticides: malathion (organophosphate), propoxur (carbamate) and permethrin (pyrethroid). LD50 values showed that, in 1998, Cx. tritaeniorhynchus was ∼100‐fold more resistant to malathion and 10‐fold more resistant to propoxur than was Cx. gelidus. This difference was attributed to Cx. tritaeniorhynchus breeding mostly in irrigated rice paddy fields, where it would have been exposed to pesticide selection pressure, whereas Cx. gelidus breeds in other types of aquatic habitats less prone to pesticide applications. Resistance in Cx. tritaeniorhynchus increased between 1984 and 1998, whereas Cx. gelidus remained predominantly susceptible.Propoxur inhibition of acetylcholinesterase (AChE) activity (the target site of organophosphates and carbamates) indicated that in 1998, frequencies of insensitive AChE‐based resistance were 9% in Cx. gelidus and 2–23% in Cx. tritaeniorhynchus, whereas in 1984 this resistance mechanism was detected only in 2% of the latter species from Anaradhapura. The AChE inhibition coefficient (ki) with propoxur was 1.86 ± 0.24 × 105 m−1 min−1 for Cx. tritaeniorhynchus from Anaradhapura in 1998.Both species were tested for activity levels of detoxifying glutathione S‐trans‐ ferases (GSTs) and malathion‐specific as well as general carboxylesterases. High activities of GSTs and carboxylesterases were detected in Cx. tritaeniorhynchus but not Cx. gelidus. Malathion‐specific carboxylesterase was absent from both species.Native polyacrylamide gel electrophoresis resolved two elevated general carboxylesterases, CtrEstβ1 and CtrEstα1, from Cx. tritaeniorhynchus and none from Cx. gelidus. CtrEstβ1 was the most intensely staining band. Gel inhibition experiments showed that both elevated esterases were inhibited by organophosphates and carbamates but not by pyrethroids.The major elevated esterase CtrEstβ1 was partially purified (15‐fold) by sequential Q‐Sepharose and phenyl Sepharose column chromatography. The bimolecular rate constant (ka) and the deacylation rate constant (k3) for the malaoxon/ enzyme interaction were 9.9 ± 1.1 × 103 m−1 min−1 and 3.5 ± 0.05 × 10−4m−1 min−1, respectively, demonstrating that the role of this enzyme in organophosphorus insecticide resistance is sequestration.
Isoenzymes of human lice: Pediculus humanus and P. capitis
Authors: Amevigbe M. D. D. , Ferrer A. , Champorie S. , Monteny N. , Deunff J. , Richard‐Lenoble D. 
Published: March 2003

SummaryHuman lice (Phthiraptera: Pediculidae) from Africa, America and Europe were electrophoresed for 28 enzymes, with special interest in metabolic factors likely to be involved with insecticide resistance. Zymogram profiles of the body louse (Pediculus humanus L. from France and U.S.A.) and the head louse (P. capitis DeGeer from France, Madagascar, Mali & Senegal) were compared. Only two enzymes, phosphoglucomutase (Pgm) and esterase 3 (Est‐3), showed electrophoretic variation. In our starch gel electrophoresis conditions, P. humanus showed three electromorphs of Pgm migrating anodally 6, 11 and 16 mm (designated alleles a, b, c, respectively). Of the putative Pgm alleles, b and c occurred in all samples of both species of lice, whereas allele a was found only in P. humanus lab strain from U.S.A. Esterase 3 had four electromorphs migrating 23, 26, 30 and 35 mm (designated alleles a, b, c and d). Among putative Est alleles, a was found only in P. capitis from Bamako (all 14 specimens aa homozygotes), allele d was found only in P. capitis from Dakar (39% frequency), whereas Est‐3 alleles b and c showed apparently balanced polymorphism in all samples of both P. humanus and P. capitis except that from Bamako. Despite the limited amount of isoenzyme variation detected (only 2/31 polymorphic loci), divergences of Est‐3 and Pgm among Pediculus populations may be relevant to their biosystematics and resistance.
Efficacy of three insect repellents against the malaria vector Anopheles arabiensis
Authors: Govere J. , Durrheim D. N. , Baker L. , Hunt R. , Coetzee M. 
Published: March 2003

SummaryThree commercial repellents marketed in South Africa: Bio‐SkincareTM (BSC, oils of coconut, jojoba, rapeseed and vitamin E), MosiguardTM towelletes with 0.574 g quwenling (p‐menthane‐3,8‐diol, PMD) and the standard deet (15% diethyl‐3‐methylbenzamide, TabardTM lotion), were compared against a laboratory colony of the mosquito Anopheles arabiensis Patton (Diptera: Culicidae), the predominant malaria vector in South Africa. Human forearms were treated with 1.2 g BSC, 0.8 g PMD towelette or 0.5 g deet and exposed to 200 hungry An. arabiensis females for 1 min, at intervals of 1–6 h post‐treatment. Tests were conducted by three adult male volunteers (aged 30–45 years, crossover controlled test design for 3 consecutive days), using their left arm for treatment and right arm for untreated control. Biting rates averaged 39–52 bites/min on untreated arms. All three repellents provided complete protection against An. arabiensis for up to 3–4 h post‐application; deet and PMD gave 90–100% protection up to 5–6 h, but BSC declined to only 52% protection 6 h post‐treatment. These results are interpreted to show that all three repellent products give satisfactory levels of personal protection against An. arabiensis for 4–5 h, justifying further evaluation in the field.
Quantification of pyrethroid insecticides from treated bednets using a mosquito recombinant glutathione S‐transferase
Authors: Enayati A. A. , Vontas J. G. , Small G. J. , McCarroll L. , Hemingway J. 
Published: March 2003

SummaryRecombinant glutathione S‐transferase (agGST1–6) from the malaria vector mosquito Anopheles gambiae Giles (Diptera: Culicidae) was expressed in Esherichia coli using a pET3a vector system. The expressed enzyme was biochemically active with reduced glutathione (GSH) and 1‐chloro‐2, 4‐dinitrobenzene (CDNB). Activity of agGST1–6 with GSH and CDNB was inhibited to different degrees by both α‐cyano and non‐α‐cyano pyrethroid insecticides. This inhibition was used to develop an assay for quantification of pyrethroids. Standard curves of insecticide concentration against percentage of enzyme inhibition or volume of iodine solution were established by spectrophotometry and iodine volumetric titration, respectively, for permethrin and deltamethrin. These assays allowed estimation of pyrethroid concentrations both spectrophotometrically and visually. For the residue assay of each insecticide, a cut‐off point of 50% of the initial pyrethroid impregnation concentration was used, which should differentiate between biologically active and inactive treated bednets. The cross‐reactivity of the primary permethrin photodegradants (3‐phenoxyalcohol and 3‐phenoxybenzoic acid) with the recombinant agGST1–6 was assayed in the same system. No agGST1–6 inhibition by the insecticide metabolites was observed, suggesting that the system is unaffected by primary permethrin metabolites and will accurately measure insecticide parent compound concentrations. The estimated pyrethroid insecticide concentrations, given spectrophotometrically and by iodine titration assay, were comparable to those obtained by direct HPLC quantification of residues extracted from bednets. Hence, it should be relatively easy to adapt this method to produce a test kit for residue quantification in the field.
Computer software for performing likelihood tests of pedigree relationship using genetic markers
Authors: Goodnight K. F. , Queller D. C. 
Published: March 2003

AbstractMolecular techniques are making ever more genetic markers available for use in parentage assignment, and measures of relatedness. We present a program, Kinship, designed to use likelihood techniques to test for any non‐inbred pedigree relationship between pairs of individuals, using single‐locus codominant genetic markers. Kinship calculates the likelihood that each pair of individuals in a data set are related by a given pedigree hypothesis, and likelihood ratios for any pair of hypotheses. The program also uses a simulation routine to attach statistical significance to its results.
Application of genomics in assessing biodiversity in wild and cultivated barley
Authors: Marmiroli N. , Maestri E. , Liviero L. , Massari A. , Malcevschi A. , Monciardini P. 
Published: March 2003

AbstractBiodiversity, the substrate for natural selection and adaptation to the environment, is of foremost importance in species conservation. Genomics, the study of the structure and function of complex genomes, can be applied to the assessment of the genetic component of biodiversity in animals and plants. Genomic analysis within the genus Hordeum, in cultivars of H. vulgare and in wild accessions of H. spontaneum, was performed by different types of molecular markers, such as restriction fragment length polymorphisms (RFLP) and long primer–polymerase chain reaction (LP–PCR), and simple sequence repeats (SSR). The aim of this approach was to compare the correlation existing between genotypic variation at specific regions of the genome, as targeted with the different probes obtained from stress‐responsive genes, and phenotypic variation, as shown by adaptation to different environments and climates. H. vulgare cultivars with contrasting growth habits (spring or winter) and H. spontaneum accessions adapted to different locations in Israel have been analysed. The results showed the existence of some tight associations between adaptive traits and markers (RFLP, LP–PCR) derived from specific genes induced in response to environmental stress. The correlation between adaptive phenotypes and genetic variation obtained with these markers was similar to that observed with SSRs. However, a considerable amount of the global genetic variation (83% in H. vulgare and 65% in H. spontaneum) seemed to have no direct correlation with the particular genetic traits involved in differentiating the individuals. Molecular markers are therefore a useful tool to target genomic regions involved in adaptation to the environment.
Random amplified polymorphic DNA (RAPD) and quantitative trait analyses across a major phylogeographical break in the Mediterranean ragwort Senecio gallicus Vill. (Asteraceae)
Authors: Comes Hans Peter , Abbott Richard J. 
Published: March 2003

AbstractRandom amplified polymorphic DNA (RAPD) and quantitative trait variation of the widespread and ephemeral Senecio gallicus were surveyed in 11 populations sampled from the Iberian Peninsula and southern France. The aim of the study was to compare population relationships and levels of geographical differentiation with chloroplast (cp) DNA and allozyme variation assessed previously in the same populations. Employing multivariate statistics, a moderate level of intraspecific differentiation was observed among populations from Iberian coastal and inland regions for both RAPDs and quantitative traits. However, RAPDs provided greater resolution in identifying additional population structure within the hypothesized, Pleistocene refugial source area of the species in coastal Iberia. A major part of the geographical subdivision in RAPD and quantitative traits was concordant with the coastal vs. inland divergence as previously inferred from cpDNA haplotype frequencies, but strongly contrasted with the geographical uniformity of the species for allozymes. This concordance across various nuclear and cytoplasmic markers (RAPDs/quantitative traits, cpDNA) suggests that geographical uniformity for allozymes is more attributable to low rates of evolution and/or small genome sampling rather than high rates of pollen dispersal, slow rates of nuclear lineage sorting, or indirect balancing selection. The present study underscores the value of using additional classes of nuclear markers for narrowing the numbers of competing causal hypotheses about intraspecific cpDNA–allozyme discrepancies and their underlying evolutionary processes.
Comparison of genetic diversity of the invasive weed Rubus alceifolius Poir. (Rosaceae) in its native range and in areas of introduction, using amplified fragment length polymorphism (AFLP) markers
Authors: Amsellem L. , Noyer J. L. , Le Bourgeois T. , Hossaert‐Mckey M. 
Published: March 2003

AbstractTheory predicts that colonization of new areas will be associated with population bottlenecks that reduce within‐population genetic diversity and increase genetic differentiation among populations. This should be especially true for weedy plant species, which are often characterized by self‐compatible breeding systems and vegetative propagation. To test this prediction, and to evaluate alternative scenarios for the history of introduction, the genetic diversity of Rubus alceifolius was studied with amplified fragment length polymorphism (AFLP) markers in its native range in southeast Asia and in several areas where this plant has been introduced and is now a serious weed (Indian Ocean islands, Australia). In its native range, R. alceifolius showed great genetic variability within populations and among geographically close populations (populations sampled ranging from northern Vietnam to Java). In Madagascar, genetic variability was somewhat lower than in its native range, but still considerable. Each population sampled in the other Indian Ocean islands (Mayotte, La Réunion, Mauritius) was characterized by a single different genotype of R. alceifolius for the markers studied, and closely related to individuals from Madagascar. Queensland populations also included only a single genotype, identical to that found in Mauritius. These results suggest that R. alceifolius was first introduced into Madagascar, perhaps on multiple occasions, and that Madagascan individuals were the immediate source of plants that colonized other areas of introduction. Successive nested founder events appear to have resulted in cumulative reduction in genetic diversity. Possible explanations for the monoclonality of R. alceifolius in many areas of introduction are discussed.
Nested cladistic analysis, phylogeography and speciation in the Timarcha goettingensis complex (Coleoptera, Chrysomelidae)
Authors: Gómez‐Zurita J. , Petitpierre E. , Juan C. 
Published: March 2003

AbstractThe Timarcha goettingensis complex is a monophyletic assemblage of closely related leaf beetles (Chrysomelidae), distributed from the north half of the Iberian Peninsula to Central Europe. Oligophagy, mountainous habitat and apterism are factors which are assumed to promote speciation in these beetles. We have used cytochrome oxidase subunit II mitochondrial DNA genealogies obtained from 31 sampling localities and a nested geographical distance analysis to assess the population structure and demographic factors explaining the geographical distributions of the mtDNA haplotypes in the T. goettingensis complex. The results show that there is a significant association between genetic structuring and geography. Inferences about the historical population processes in the species complex are discussed, being in general in accordance with contiguous range expansions and past fragmentations. The use of the cohesion species concept approach suggests the existence of several systematic ranks among the different T. goettingensis populations, which is in part supported by ecological traits such as trophic selection and altitudinal distribution.
Phylogeography of the bullhead Cottus gobio (Pisces: Teleostei: Cottidae) suggests a pre‐Pleistocene origin of the major central European populations
Authors: Englbrecht C. C. , Freyhof J. , Nolte A. , Rassmann K. , Schliewen U. , Tautz D. 
Published: March 2003

AbstractThe bullhead Cottus gobio is a small, bottom‐dwelling fish consisting of populations that have not been subject to transplantations or artificial stocking. It is therefore an ideal model species for studying the colonization history of central European freshwater systems, in particular with respect to the possible influences of the Pleistocene glaciation cycles. We sampled Cottus populations across most of its distribution range, with a special emphasis on southern Germany where the major European drainage systems are in closest contact. Mitochondrial
d‐loop sequencing of more than 400 specimens and phylogenetic network analysis allowed us to draw a detailed picture of the colonization of Europe by C. gobio. Moreover, the molecular distances between the haplotypes enabled us to infer an approximate time frame for the origin of the various populations. The founder population of C. gobio stems apparently from the Paratethys and invaded Europe in the Pliocene. From there, the first colonization into central Europe occurred via the ancient lower Danube, with a separate colonization of the eastern European territories. During the late Pliocene, one of the central European populations must have reached the North Sea in a second step after which it then started to colonize the Atlantic drainages via coastal lines. Accordingly, we found very distinct populations in the upper and lower Rhine, which can be explained by the fact that the lower Rhine was disconnected from the upper Rhine until ≈ 1 million years ago (Ma). More closely related, but still distinct, populations were found in the Elbe, the Main and the upper Danube, all presumably of Pleistocene origin. Intriguingly, they have largely maintained their population identity, despite the strong disturbance caused by the glaciation cycles in these areas. On the other hand, a mixing of populations during postglacial recolonization could be detected in the lower Rhine and its tributaries. However, the general pattern that emerges from our analysis suggests that the glaciation cycles did not have a major impact on the general population structure of C. gobio in central Europe.
Relative fitness components measured with competitive PCR
Authors: Wooninck L. M. , Warner R. R. , Fleischer R. C. 
Published: March 2003

AbstractIn mating systems with sperm competition, paternity is frequently established with modern DNA techniques. These methods are often expensive and cumbersome, and can be especially difficult for highly fecund species. An additional objective of many paternity studies is to discover the relationship between sperm number and paternity. We present here a competitive polymerase chain reaction (PCR) protocol, coupled with the use of an automated sequencer, that has two functions: (i) to measure directly relative sperm output of males in sperm competition; and (ii) to estimate paternity distributions of large numbers of offspring simultaneously. Our technique was calibrated using a microsatellite locus of the bluehead wrasse, Thalassoma bifasciatum, with the result that product ratio after competitive PCR accurately reflected the initial template proportions of known mixtures of DNA. When we applied our technique to multiple larvae of separate mating events we found that paternity distributions estimated with the competitive PCR technique closely matched the estimates derived from the traditional method of pooling paternity data from individual larvae. Finally, we compared paternity of these spawns with relative sperm contribution estimates. This comparison suggests that ejaculate size alone does not predict a male’s proportion of paternity within the group.
Genetic variation within and among patches of the clonal species, Vaccinium stamineum L.
Authors: Kreher S. A. , Foré S. A. , Collins B. S. 
Published: March 2003

AbstractOnce thought to be dominated by a few genets, clonal plant populations can contain high levels of genetic diversity. Sexual reproduction and vegetative growth strategy affect the amount and distribution of genetic diversity within clonal plant populations. We determined the scale of genetic diversity in a population of Vaccinium stamineum, a clonal shrub that forms discrete patches. Using the random amplified polymorphic DNA (RAPD) technique, we surveyed the genetic diversity of V. stamineum within and among patches from a 1‐ha site. We found 67 unique RAPD profiles among the 99 sampled individuals from 22 patches. In two patches, all the sampled individuals had the same RAPD profile. In seven patches, every individual sampled had a different RAPD profile. The remaining patches showed mixed RAPD profiles which suggested both clonal and sexual reproduction. Each unique RAPD profile was restricted to one patch (with one exception), which suggests that clonal growth occurs at the patch scale. High levels of genetic variation within some patches may be explained by somatic mutation; however, seedling recruitment is a more likely explanation.
Microsatellite analysis of genetic diversity in African buffalo (Syncerus caffer) populations throughout Africa
Authors: Van Hooft W. F. , Groen A. F. , Prins H. H. T. 
Published: March 2003

AbstractGenetic diversity in nine African buffalo (Syncerus caffer) populations throughout Africa was analysed with 14 microsatellites to study the effects of rinderpest epidemics and habitat fragmentation during the 20th century. A gradient of declining expected heterozygosity was observed among populations in Save Valley Conservancy (Zimbabwe), and northern and southern Kruger National Park (South Africa). This was explained by a high mortality in northern Kruger National Park during the rinderpest pandemic at the end of the 19th century followed by recolonization from neighbouring populations, resulting in intermediate heterozygosity levels in northern Kruger National Park. In other populations expected heterozygosity was very high, indicating that rinderpest and recent habitat fragmentation had a limited effect on genetic diversity. From expected heterozygosity, estimates of long‐term effective population size were derived. Migration rates among populations in eastern and southern Africa were very high, as shown by a weak isolation by distance and significant correlation in allele frequencies between populations. However, there were indications that dry habitats could limit migration. Genetic distances within buffalo in central Africa were relatively large, supporting their status as distinct subspecies. Finally, it was observed that the higher polymorphic microsatellites were less sensitive at detecting isolation by distance and differences inNe, which may be a result of the high mutation pressure at these loci.