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Starch Gel Electrophoresis (starch + gel_electrophoresis)
Selected AbstractsMechanisms of resistance to DDT and pyrethroids in Patagonian populations of Simulium blackfliesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2003C. M. Montagna Abstract. Mixed populations of the pest blackflies Simulium bonaerense Coscarón & Wygodzinsky, S. wolffhuegeli (Enderlein) and S. nigristrigatum Wygodzinsky & Coscarón (Diptera: Simuliidae) are highly resistant to DDT and pyrethroids in the Neuquén Valley, a fruit-growing area of northern Patagonia, Argentina. As these insecticides have not been used for blackfly control, resistance is attributed to exposure to agricultural insecticides. Pre-treatment with the synergist piperonyl butoxide (PBO) reduced both DDT and fenvalerate resistance, indicating that resistance was partly due to monooxygenase inhibition. Pre-treatment with the synergist tribufos to inhibit esterases slightly increased fenvalerate toxicity in the resistant population. Even so, biochemical studies indicated almost three-fold higher esterase activity in the resistant population, compared to the susceptible. Starch gel electrophoresis confirmed higher frequency and staining intensity of esterase electromorphs in the resistant population. Incomplete synergism against metabolic resistance indicates additional involvement of a non-metabolic resistance mechanism, such as target site insensitivity, assumed to be kdr -like in this case. Glutathione S-transferase activities were low and inconsistent, indicating no role in Simulium resistance. Knowing these spectra of insecticide activity and resistance mechanisms facilitates the choice of more effective products for Simulium control and permits better coordination with agrochemical operations. [source] Population genetic studies of hilsa shad, Tenualosa ilisha (Hamilton), in Bangladesh waters: evidence for the existence of separate gene poolsFISHERIES MANAGEMENT & ECOLOGY, Issue 5 2000M. Rahman Hilsa shad, Tenualosa ilisha (Hamilton), in Bangladesh is found in inland rivers, estuaries and the marine environment, throughout the year, but the peak catch period is during upstream migration. Tissue (white muscle, liver, brain) samples (total 640 specimens) were collected from three different localities, representing marine, brackish and fresh water, during the monsoon in the summer of the years 1993,1996 to identify genetic markers and study the population structure of this species. The samples were analysed by starch gel electrophoresis and isoelectric focusing, and stained for 15 enzymes and general muscle proteins. Only phosphoglucomutase, aspartate amino transferase, esterase and unidentified muscle proteins were found to be polymorphic. The allele frequencies for the samples collected in the marine environment deviated from corresponding samples from freshwater and estuarine localities, indicating that hilsa shad in Bangladesh waters comprise more than one gene pool. [source] Reproductive modes and genetic polymorphism in the tardigrade Richtersius coronifer (Eutardigrada, Macrobiotidae)INVERTEBRATE BIOLOGY, Issue 1 2003Lorena Rebecchi Abstract. Allozymes were assessed by starch gel electrophoresis in 3 populations of a eutardigrade, Richtersius coronifer, with different reproductive modes. One population from Italy (with 2 sub-populations) was amphimictic and 2 populations (1 from Italy and 1 from Sweden) were parthenogenetic. All populations, irrespective of their reproductive mode, were diploid with the same chromosome number (2n=12) and had bivalents in the oocytes. Of the 14 loci analyzed, only 3 were polymorphic. The amphimictic population had a higher degree of genetic variability (mean heterozygosity >0.25) than the parthenogenetic populations (mean heterozygosity of the 2 populations <0.01). In all female populations, allele frequencies at all 3 loci deviated from Hardy-Weinberg equilibria due to heterozygote deficiency. These results support a hypothesis of automictic parthenogenesis in R. coronifer. [source] Genetic variation and structure in six Rhododendron species (Ericaceae) with contrasting local distribution patterns in Hong Kong, ChinaMOLECULAR ECOLOGY, Issue 7 2000Sai-Chit Ng Abstract Genetic variability of six rhododendrons with contrasting local distribution patterns in Hong Kong was assessed by starch gel electrophoresis. Rhododendron championiae, R. hongkongense and R. simiarum are locally rare with disjunct distributions, R. moulmainense is restricted and R. farrerae and R. simsii are common. For each species, 13,18 allozyme loci representing 12,16 enzyme systems were scored. The six species showed similar levels of genetic variations (HT ranged from 0.209 to 0.386 and AT ranged from 2.4 to 4.1) which are high compared to plants with similar life history traits. Genetic structure, in contrast, varied greatly between species, with FST ranging from 0.056 to 0.393. The three rarest species had high genetic differentiation (FST and FPT) and distinct geographical patterns, while the other three had low differentiation and little or no geographical structure. These differences are attributed to both present distributions and historical changes following deforestation within the last 1000 years. The conservation implications of these results are discussed. [source] | ||||||||||