Anti-oviposition activities of used sock media against a dengue vector: prospects of eco-friendly control and solutions to pollution.

Yearly, huge amounts of sock refuse are discarded into the environment. Socks contain many molecules, and worn ones, which are rich in smell-causing bacteria, have a strong influence on animals' behaviors. But the impacts of sock odor on the oviposition behavior of dengue vectors are unknown. We assessed whether Aedes albopictus changes its oviposition activity in response to the presence of used socks extract (USEx) in potential breeding grounds, using choice and no-choice bioassays (NCB). When furnished even chances to oviposit in two sites holding USEx and two others containing water (control), Ae. albopictus deposited significantly less eggs in USEx than in water sites. A similar pattern of oviposition preference was also observed when there were more oviposition options in water. When there were greater oviposition opportunities in USEx sites, Ae. albopictus oviposited preferentially in water. Females laid significantly more eggs during the NCB involving water than USEx. Also, significantly more mature eggs were retained by females in the NCB with USEx than in that with water. These observations strongly suggest the presence of molecules with either repellent or deterrent activities against Ae. albopictus females and provide an impetus to advocate the integration of used socks in dengue control programs. Such applications could be a realistic end-of-life recourse to reroute this waste from landfills.

The phenetic structure of Aedes albopictus.

The large and recent migrations of the main vector of the Chikungunya virus, Aedes albopictus, raise questions about the epidemiological impact of possible microevolutionary changes in new territories. Quantitative traits are suitable to detect such changes as induced by environmental adaptations, local competition and founder effects. Using landmark-based geometric morphometrics, we compared the size and shape of 22 populations (1572 females) of Ae. albopictus. The collection sites covered five countries around the world, with special emphasis on Asia, which is assumed to be the origin of the vector. Some collections came from places where an important epidemic outbreak of Chikungunya has recently occurred. Quantitative comparisons were based on 18 anatomical landmarks on the wing. To contrast geographic and possible interspecific shape variation, close species were introduced in the sample, namely five Aedes riversi and nine Ae. flavopictus from Japan. The three species had similar size, but they were clearly separated by shape. Within Ae. albopictus, there was general agreement on size variation with the available climatic data. Shape variation was less related to climatic data than to either geography or a known itinerary of past territorial expansion. Thus, two main clusters were distinguished by wing shape variation: the first one composed of the Southeast Asian sample, the second one grouping Japan, Florida, Hawaii and the Reunion Island samples. The Southeast Asian countries, assumed to be at the origin of the geographic expansion of the mosquito, had similar wings and constituted a distinct group where localities clustered into northern and southern localities. Contrasting with this homogeneous group, very distant localities such as United States (US) and Japan shared a common shape pattern. The US Ae. albopictus samples (Hawaii and Florida) were indeed very similar to the Japanese samples, with Florida behaving exactly like a northern Japanese locality, close to Tokyo and Yokohama. Shape proximity among these distant areas could be explained by a common and relatively recent ancestor, as generally suggested in the literature. The three Reunion Island samples conformed a group external to the Southeast Asian countries, loosely connected to the remaining localities. Thus, areas where recent epidemics took place, the Reunion Island and the southernmost localities of Thailand, did not cluster together, but represented separate groups. In sum, the size of the wing was apparently under the influence of climatic factors, while its shape could contribute information on species and geographic differences. Apparent departures from expectations based on geography were explained by known past and present migratory routes. These patterns of shape variation were compatible with genetic drift, suggesting microevolutionary changes probably induced by the expansion of the Ae. albopictus mosquito.

Whole-body kinetic image of a redox probe in mice using Overhauser-enhanced MRI.

Overhauser-enhanced MRI (OMRI) enables visualization of free radicals in animals based on dynamic nuclear polarization. Real-time data of tissue redox status gathered from kinetic images of redox-sensitive nitroxyl radical probes using OMRI provided both anatomic and physiological information. Phantom experiments demonstrated the linear correlation between the enhancement factor and the concentration of a membrane-impermeable probe, carboxy-PROXYL (3-carboxy-2,2,5,5-tetramethyl- pyrrolidine-1-oxyl). Whole-body OMRI images illustrated the in vivo kinetics of carboxy-PROXYL for 25 min. Initial distribution was observed in lung, heart, liver, and kidney, but not brain, corresponding to its minimal lipophilicity. Based on these images (pixel size, 1.33 × 1.33 mm; slice thickness, 50mm), a time-concentration curve with low coefficient of variance (<0.21) was created to assess pharmacokinetic behaviors. A biexponential curve showed a distribution phase from 1 to 10 min and an elimination phase from 15 to 25 min. The α rate constant was greater than the ß rate constant in ROIs, confirming that its pharmacokinetics obeyed a two-compartment model. As a noninvasive technique, combining OMRI imaging with redox probes to monitor tissue redox status may be useful in acquiring valuable information regarding organ function for preclinical and clinical studies of oxidative diseases.

Curcumin I protects the dopaminergic cell line SH-SY5Y from 6-hydroxydopamine-induced neurotoxicity through attenuation of p53-mediated apoptosis.

Oxidative stress (OS) plays a pivotal role in the pathogenesis of Parkinson's disease (PD). 6-Hydroxydopamine (6-OHDA) is a neurotoxin used to induce oxidative cell death of dopaminergic neurons in experimental models of PD. Curcumin I, or diferuloylmethane is a pure compound isolated from Curcuma longa Linn. that has been reported to have neuroprotective properties. The precise mechanism, however, remains unclear. This study aims to elucidate the mechanisms by which curcumin I exerts its effects, using 6-OHDA-induced neurotoxicity in the human dopaminergic cell line SH-SY5Y. In our experiments, pretreatment with curcumin I improved cell viability, and significantly reduced reactive oxygen species (ROS). Further investigations revealed a reduction of p53 phosphorylation and decrease of the Bax/Bcl-2 ratio, as measured by mRNA expression and protein level. Taken together, these findings indicate that curcumin I protects dopaminergic neurons from 6-OHDA-induced toxicity via the reduction of ROS production, and subsequent attenuation of p53 phosphorylation and reduction of the Bax/Bcl-2 ratio.

Climate associated size and shape changes in Aedes aegypti (Diptera: Culicidae) populations from Thailand.

In spite of the adult body size variability of Aedes aegypti (Linnaeus) and its likely association with life history and vectorial capacity, the causes of size variation itself have been only partially identified. In particular, possible important factors such as climatic variation have not received much attention. The objective of this 2-year study was to describe from field collections the relationship of Ae. aegypti metric properties with available climatic data. The study took place in a dengue hyperendemic area of Thailand. Fourth instar larvae (L(4)) and pupae were collected from the same breeding places allowing the comparisons between seven successive collections, four in 2007 and three in 2008. Climatic data were relative humidity (RH) and temperature (T). They were considered for the periods covering either the pre-imaginal development or, assuming heritability of size, the previous generation. The pre-imaginal period was further subdivided into embryonic and larval phases of development. Size was estimated by traditional and geometric techniques, the latter based on 18 landmarks collected at the intersections of veins also allowing estimation of shape. The shape variation of the wing followed similar patterns as for size and was shown to be a passive allometric change. No significant correlation of size or shape could be disclosed with T. In contrast, significant correlation with RH was found during two periods of examination: (i) the period affecting the generation previous to the time of collection, suggesting possible selective mechanisms on genitors, and (ii) the one occurring during pre-imaginal development. The subdivision of the latter into embryonic and larval phases allowed to evidence a possible selecting effect on embryonic development. The selection would act through the resistance to water loss which is known to depend on the relative surface of the cuticle. In conclusion, our data highlight the importance of the emerged period of Ae. aegypti eggs as a critical time for the size of future adults, and point to the relative humidity as the likely selecting factor.

Paraoxonase and platelet-activating factor acetylhydrolase activities in lipoproteins of beta-thalassemia/hemoglobin E patients.

BACKGROUND: Iron-induced oxidative stress may be implicated in the alteration of the lipoprotein-associated antioxidant enzymes paraoxonase 1 (PON1) and platelet-activating factor acetylhydrolase (PAF-AH), leading to atherosclerosis-related vascular complication in patients with beta-thalassemia hemoglobin E (beta-thal/Hb E). METHODS: Plasma and lipoprotein enzyme activities of PON1 and PAF-AH were studied in 13 mild to moderate and 15 severe cases of beta-thal/Hb E in comparison with 15 normal subjects. RESULTS: PON1 activity was significantly reduced in association with oxidative stress in the patients. There were significant correlations between high-density lipoprotein (HDL)-PON1 activity and oxidative stress markers, including plasma levels of alpha-tocopherol (r=0.694 p<0.001) and the ratio of cholesteryl linoleate to cholesteryl oleate (CL/CO, r=0.662, p<0.001) in HDL. On the other hand, PAF-AH activity was markedly increased in patients by approximately two-fold and three- to four-fold in plasma and lipoproteins, respectively. Significant correlations of low-density lipoprotein (LDL) and HDL-PAF-AH activity with plasma iron, alpha-tocopherol and the CL/CO ratio were also demonstrated. CONCLUSIONS: We suggest that impairment of PON1 activity may be directly caused by oxidative damage, while increased PAF-AH activity possibly results from oxidative stress-induced inflammatory response in beta-thal/Hb E patients.