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Abstract Londrina is the fourth most populous city in southern Brazil. Its subtropical weather with rain in all seasons, as well as its high population density, make the city perfect for the Aedes aegypti (Linnaeus, 1762) life cycle. Over the last few years, Londrina presented high infestation indexes and was one of the cities with the most reported cases of dengue. Uncontrolled use of synthetic insecticides may influence the mosquito's genetic composition. In this paper, we studied mitochondrial DNA and kdr mutations in Aedes aegypti. The analysis of the ND4 gene in 330 specimens showed the presence of 27 haplotypes. The pyrethroid resistance alleles (kdr) evaluated are present in the collected populations, with a 50% frequency of the Val1016Ile and 48% of the Phe1534Cys mutations. Such analysis of the mutations in the populations collected at the State University of Londrina's campus - a microenvironment that differs from the rest of the city - showed frequencies of 57% and 62%, respectively. The low gene flow observed, Nm = 0.11 and Nm = 0.10, along with the elevated differentiation, Fst = 0.19 and Fst = 0.18, among populations suggest an influence of genetic drift. The strong presence of resistance alleles kdr in the city is evident, which demonstrates that even with the interruption of the use of pyrethroids by the National Dengue Control Program, resistance may be maintained due to domestic use. Thus, the results have shown the need for genetic monitoring, alongside other entomological surveillance monitoring tools, to create strategies of mosquito control.
ABSTRACT
ABSTRACT Aedes (Stegomyia) aegypti is the vector responsible for the transmission of the viruses that cause zika, yellow and chikungunya fevers, the four dengue fever serotypes (DENV - 1, 2, 3, 4), and hemorrhagic dengue fever in tropical and subtropical regions around the world. The present study investigated the genetic differentiation of the 15 populations of this vector in the Brazilian state of Maranhão, based on the mitochondrial ND4 marker. A total of 177 sequences were obtained for Aedes aegypti, with a fragment of 337 bps, 15 haplotypes, 15 polymorphics sites, haplotype diversity of h = 0.6938, and nucleotide diversity of π = 0.01486. The neutrality tests (D and Fs) were not significant. The AMOVA revealed that most of the variation (58.47%) was found within populations, with FST = 0.41533 (p < 0.05). Possible isolation by distance was tested and a significant correlation coefficient (r = 0.3486; p = 0.0040) was found using the Mantel test. The phylogenetic relationships among the 15 haplotypes indicated the existence of two distinct clades. This finding, together with the population parameters, was consistent with a pattern of genetic structuring that underpinned the genetic differentiation of the study populations in Maranhão, and was characterized by the presence of distinct lineages of Aedes aegypti.
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The mosquito Aedes aegypti is the main Dengue vector in Latin America. This study investigated the genetic structure of this vector using samples collected in Venezuela, Colombia, Peru, Mexico, Argentina, Puerto Rico, and French Guiana. We examined the distribution of a 246-basepair region of the NADH dehydrogenase subunit 4 mitochondrial gene among a total of 369 Ae. aegypti from all the populations. This gene was amplified by the polymerase chain reaction and tested for variation using single strand conformation polymorphism analysis. Twelve haplotypes were detected among all the countries sampled and grouped into two clades. Significant differentiation was detected among the populations studied and these were not genetically isolated by distance.
El mosquito Aedes aegypti es el principal vector del Dengue en los países latinoamericanos. En este estudio se investigó la estructura genética de este vector en muestras colectadas en Venezuela, Colombia, Perú, Mexico, Argentina, Puerto Rico y Guyana Francesa. Nosotros examinamos la distribución de una región de 246 pares de bases del gen mitochondrial de la subunidad 4 de la NADH deshidrogenasa entre un total de 369 Ae. aegypti de todas las poblaciones. Este gen fue amplificado por la reacción en cadena de la polimerasa y la variación se determinó usando el análisis de polimorfismos de conformación de cadena simple. Doce haplotipos se detectaron entre todos los países y se repartieron en dos clados. Una diferenciación significativa se detectó entre las poblaciones y estas no se encontraron genéticamente aisladas por distancia.
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AIM: To explore the molecular mechanism of asthenospermia(AST) by preliminary screening of nucleotide sequences from the ND3 and ND4L genes of mitochondrial DNA(mtDNA). METHODS: Samples from 50 AST patients and 42 age-matched normal controls were collected according to the WHO criteria. Density gradient centrifugation was applied to separate spermatozoa with different vigor. The ND3 and ND4L genes of mtDNA were amplified and sequenced directly from the extracted genomic DNA from AST patients and normal controls. The sequences were compared with revised Cambridge Reference Sequence(rCRS) to analyze the variants. RESULTS: A total of 22 nucleotide variations were found in ND3 and ND4L genes of mtDNA in asthenospermia group and control group. G10320A, A10398G and T10609C were missense mutations, while A10157G and A10313C were the reported for the first time in this study. Haplotype N in patients with AST(33/50) was higher than that in control group(14/42, P<0.05), and haplotype R9 in patients with AST(15/50) was also higher than that in control group(4/42, P<0.05) through genetic testing of ND3 gene. Rates of sperm progressive motility of haplotype F1, F2 and R9 were significantly lower than those of haplotype M and M rest. Two haplotype differences, haplotype M and N, were found in the same AST patient's spermatozoas which had different vigor. Haplotype M had stronger vigor, while haplotype N had lower vigor. By sequencing ND3 gene of mtDNA from 50 AST patients, we detected G10310A heteroplasmic mutation in 2 specimens of asthenospermia with poor and moderate motility spermatozoa, respectively. No mutation occurred in good motility spermatozoa. CONCLUSION: Haplotype of mitochondrial may have some correlation with sperm motility. The nt10398G-10400T polymorphisms may have benefit for sperm motility, whereas the mutation in nt10310A may impair sperm motility.
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Anopheles darlingi is the most important Brazilian malaria vector, with a widespread distribution in the Amazon forest. Effective strategies for vector control could be better developed through knowledge of its genetic structure and gene flow among populations, to assess the vector diversity and competence in transmitting Plasmodium. The aim of this study was to assess the genetic diversity of An. darlingi collected at four locations in Porto Velho, by sequencing a fragment of the ND4 mitochondrial gene. From 218 individual mosquitoes, we obtained 20 different haplotypes with a diversity index of 0.756, equivalent to that found in other neotropical anophelines. The analysis did not demonstrate significant population structure. However, haplotype diversity within some populations seems to be over-represented, suggesting the presence of sub-populations, but the presence of highly represented haplotypes complicates this analysis. There was no clear correlation among genetic and geographical distance and there were differences in relation to seasonality, which is important for malarial epidemiology.
Subject(s)
Animals , Anopheles/genetics , DNA, Mitochondrial/genetics , Genetic Variation , Insect Vectors/genetics , Anopheles/classification , Brazil , Haplotypes , Insect Vectors/classification , Population Density , SeasonsABSTRACT
Objective To investigate the sequence characteristic of black bear's mitochondrial NADH-ubiquinone oxidoreductase chain 4 gene(ND4).Methods Primers were designed according to certain species' NADH-ubiquinone oxidoreductase ND4 in which the DNA sequence had been reported.The DNA sequence was amplified by PCR from the Asian black bear Sichuan subspecies's(Ursus thibetanus mupinensis)hair-follicle tissue total DNA and were analyzed with its amino acid sequence.Results The ND4 gene sequence length was 1 402 bp and contained a 1 377-nucleotide open reading frame encoding 459 amino acid residues.The amino acid sequence's pI was 9.37 and weight was 51.5?10 3.The DNA sequence and corresponding amino acid sequence of black bear's ND4 gene had the high similarity with those of other mammalian animals' ND4 gene,and the similarity was 89% to 91% and 94% to 95%.The result of phylogenetic tree was basically consistent with the traditional species system phylogenetic relations.Topology prediction showed the Asian black bear Sichuan subspecies's ND4 proteins contained N-glycosylation site,kinase C phosphorylation sites,casein kinase Ⅱ phosphorylation site,N-myristoylation site and leucine-rich region.In addition,black bear's ND4 protein contained leucine zipper pattern and Leucine-rich region.Conclusion The mammalia animal's ND4 gene has the high conservative nature.The pretein coded by ND4 gene has high uniformity in the function.