Genetic variability of a population of Aedes aegypti from Paraná, Brazil, using the mitochondrial ND4 gene

Genetic variability of a population of Aedes aegypti from Paraná, Brazil, using the mitochondrial ND4 gene. To analyze the genetic variability of populations of Aedes aegypti, 156 samples were collected from 10 municipalities in the state of Paraná, Brazil. A 311 base pairs (bp) region of the NADH dehydrogenase subunit 4 (ND4) mitochondrial gene was examined. An analysis of this fragment identified eight distinct haplotypes. The mean genetic diversity was high (h = 0.702; p = 0.01556). AMOVA analysis indicated that most of the variation (67%) occurred within populations and the F ST value (0.32996) was highly significant. F ST values were significant in most comparisons among cities. The isolation by distance was not significant (r = -0.1216 and p = 0, 7550), indicating that genetic distance is not related to geographic distance. Neighbor-joining analysis showed two genetically distinct groups within Paraná. The DNA polymorphism and AMOVA data indicate a decreased gene flow in populations from Paraná, which can result in increased vectorial competence.

Physiological implications of the regulation of vacuolar H+-ATPase by chloride ions

Vacuolar H+-ATPase is a large multi-subunit protein that mediates ATP-driven vectorial H+ transport across the membranes. It is widely distributed and present in virtually all eukaryotic cells in intracellular membranes or in the plasma membrane of specialized cells. In subcellular organelles, ATPase is responsible for the acidification of the vesicular interior, which requires an intraorganellar acidic pH to maintain optimal enzyme activity. Control of vacuolar H+-ATPase depends on the potential difference across the membrane in which the proton ATPase is inserted. Since the transport performed by H+-ATPase is electrogenic, translocation of H+-ions across the membranes by the pump creates a lumen-positive voltage in the absence of a neutralizing current, generating an electrochemical potential gradient that limits the activity of H+-ATPase. In many intracellular organelles and cell plasma membranes, this potential difference established by the ATPase gradient is normally dissipated by a parallel and passive Cl- movement, which provides an electric shunt compensating for the positive charge transferred by the pump. The underlying mechanisms for the differences in the requirement for chloride by different tissues have not yet been adequately identified, and there is still some controversy as to the molecular identity of the associated Cl--conducting proteins. Several candidates have been identified: the ClC family members, which may or may not mediate nCl-/H+ exchange, and the cystic fibrosis transmembrane conductance regulator. In this review, we discuss some tissues where the association between H+-ATPase and chloride channels has been demonstrated and plays a relevant physiologic role.

Meat quality characteristics of exotic and SPRD crossbred goats from the semiarid region

Thirty-two intact male goats from four genetic groups (eight pure-bred Boers, eight ¾ Boer + ¼ SPRD crossbreeds, eight ½ Boer + ½ SPRD crossbreeds, and eight ½ Anglo Nubian + ½ SPRD crossbreeds) were evaluated for meat quality. The goats were reared in confinement and slaughtered at the average live weight of 29 kg. Temperature and pH decrease in the longissimus dorsi muscle was determined for 24 hours, and analyses of colour, cooking loss, water-holding capacity, and sensory attributes were also performed. Genotype significantly (P < 0.05) influenced the confinement period; ½ Boer + ½ SPRD crossbreeds required the most time in confinement to reach the target weight, while the pure-bred Boers required the least time. Genotype also significantly influenced (P < 0.05) the weight loss due to cooking, shearing force, colour (intensity of yellowness and luminescence), and the sensory attributes of flavour, odour, and raw colour of the meat. The crossing of exotic Boer and Anglo Nubian breeds with the native SPRD resulted in a goat meat of high quality.