BACKGROUND Culex quinquefasciatus, a cosmopolitan, domestic, and highly anthropophilic mosquito, is a vector of pathogenic arboviruses such as West Nile virus and Rift Valley virus, as well as lymphatic filariasis. The current knowledge on its reproductive physiology regarding vitellogenin expression in different tissues is still limited. OBJECTIVES In this study, we analysed the transcriptional profiles of vitellogenin genes in the fat body and ovaries of C. quinquefasciatus females during the first gonotrophic cycle. METHODS C. quinquefasciatus ovaries and/or fat bodies were dissected in different times during the first gonotrophic cycle and total RNA was extracted and used for reverse transcription polymerase chain reaction, quantitative real time-PCR, and in situ hybridisation. FINDINGS We confirmed the classical descriptions of the vitellogenic process in mosquitoes by verifying that vitellogenin genes are transcribed in the fat bodies of C. quinquefasciatus females. Using RNA in situ hybridisation approach, we showed that vitellogenin genes are also transcribed in developing ovaries, specifically by the follicle cells. MAIN CONCLUSIONS This is the first time that vitellogenin transcripts are observed in mosquito ovaries. Studies to determine if Vg transcripts are translated into proteins and their contribution to the reproductive success of the mosquito need to be further investigated. cosmopolitan domestic filariasis limited study C andor or reaction timePCR, timePCR PCR, PCR time-PCR approach cells investigated

Abstract: Purpose: to evaluate the effect of dentifrice pH and fluoride concentration ([F]) on fluoride uptake on the biofilm and nails of children from a non-fluoridated area. Methods: two hundred and twenty-eight two- to four-year-old children were randomly allocated into 3 groups according to the type of dentifrice: G1: 1100 μg F/g, pH 4.5 (n = 76); G2: 750 μg F/g, pH 4.5 (n = 74); and G3: 1100 μg F/g, pH 7.0 (n = 78). Nails were collected at 4, 8, and 12 months after starting dentifrice use and biofilm was collected 5 and 60 minutes after toothbrushing. The concentrations of F in nails and biofilm were analyzed by HMDS facilitated diffusion. Data were analyzed by Kruskal-Wallis/Mann-Whitney's test and the comparison between biofilm collection times was done using Wilcoxon test (p £ 0.05). Results: a significant reduction of [F] in biofilm was observed 60 minutes after toothbrushing, regardless of the dentifrice used. However, 5 minutes after toothbrushing, G1 had a significantly higher [F] compared to G2 and G3, and 60 minutes after toothbrushing, [F] was significantly higher for G1 and G2 compared to G3. G1 and G3 had significantly higher [F] in the nails compared to G2. Conclusion: a lower dentifrice concentration is a relevant factor for the reduction of excessive fluoride intake. The use of a low-F acidified dentifrice combines the reduction of fluoride uptake with caries prevention by leading to greater incorporation of F into the biofilm over time.

The vitellogenic process in Culex quinquefasciatus, which is triggered by a blood meal, involves the synthesis, distribution and storage of the nutrients necessary for embryo development. The fat body of an adult female Cx. quinquefasciatus revealed two cell types: large trophocytes and small, eosinophilic, "oenocyte-like" cells, which show no morphological changes throughout the gonotrophic cycle. Trophocytes, which only begin to synthesise vitellogenin (Vg) 12 h post-blood meal (PBM), undergo a series of morphological changes following engorgement. These changes include the expansion of the rough endoplasmic reticulum (RER) and Golgi complex, which are later destroyed by autophagosomes. At 84 h PBM, trophocytes return to their pre-engorgement morphology. The ovarian follicles of non-blood-fed Cx. quinquefasciatus contain a cluster of eight undifferentiated cells surrounded by follicular epithelium. After engorgement, the oocyte membrane facing the perioocytic space increases its absorptive surface by microvilli development; large amounts of Vg and lipids are stored between 24 and 48 h PBM. Along with yolk storage in the oocyte, follicular cells exhibit the development of RER cisternae and electron-dense granules begin to fill the perioocytic space, possibly giving rise to endochorion. Later in the gonotrophic cycle, electron-dense vesicles, which are possible exochorion precursors, fuse at the apical membrane of follicular cells. This fusion is followed by follicular cell degeneration.