Phylogenetic Analysis of Aedes aegypti Based on Mitochondrial ND4 Gene Sequences in Almadinah, Saudi Arabia.

BACKGROUND: Aedes aegypti is the main vector of the yellow fever and dengue virus. This mosquito has become the major indirect cause of morbidity and mortality of the human worldwide. Dengue virus activity has been reported recently in the western areas of Saudi Arabia. There is no vaccine for dengue virus until now, and the control of the disease depends on the control of the vector. OBJECTIVES: The present study has aimed to perform phylogenetic analysis of Aedes aegypti based on mitochondrial NADH dehydrogenase subunit 4 (ND4) gene at Almadinah, Saudi Arabia in order to get further insight into the epidemiology and transmission of this vector. MATERIALS AND METHODS: Mitochondrial ND4 gene was sequenced in the eight isolated Aedes aegypti mosquitoes from Almadinah, Saudi Arabia, sequences were aligned, and phylogenetic analysis were performed and compared with 54 sequences of Aedes reported in the previous studies from Mexico, Thailand, Brazil, and Africa. RESULTS: Our results suggest that increased gene flow among Aedes aegypti populations occurs between Africa and Saudi Arabia. CONCLUSIONS: Phylogenetic relationship analysis showed two genetically distinct Aedes aegypti in Saudi Arabia derived from dual African ancestor.

Effects of light and low oxygen tension on pigment biosynthesis in Halobacterium salinarum, revealed by a novel method to quantify both retinal and carotenoids.

A novel method for analyzing halobacterial pigments was developed, in which retinal was liberated from halobacterial rhodopsins as retinal oxime by hydroxylamine, ethyl beta-apo-8'-carotenoate was introduced as an internal standard, and the pigments including bacterioruberin and beta-carotene were analyzed by HPLC at the same time. With this method, we revealed that light enhances the biosynthesis of bacterioruberin and the conversion of beta-carotene to retinal, but does not affect beta-carotene biosynthesis in Halobacterium salinarum strain Oyon Moussa-16. Low oxygen tension given in the light brought a slight increase in retinal accumulation, although its biosynthesis from beta-carotene is an oxygenation reaction. This paradox could be explained by the increase in beta-carotene biosynthesis.