Essential requirement of reduced glutathione (GSH) for the anti-oxidant effect of the flavonoid quercetin

We have analyzed the anti- or pro-oxidant effects of the flavonoid quercetin (QU) by evaluating, in U937 cell line, hydrogen peroxide (H(2)O(2)), superoxide anion reduced glutathione (GSH) content, mitochondrial membrane potential, DNA content, phosphatidylserine exposure on the outer face of the plasma membrane and cell viability. Polychromatic flow cytometry was used to evaluate in the same cells several functional parameters. For short periods of treatment QU exerted an anti-oxidant effect (decrease in H(2)O(2) levels), whereas for long periods it showed a pro-oxidant activity (increase in ). In these conditions, GSH content was reduced, and this correlated with a lack of anti-oxidant activity of QU, which in turn could be correlated with proapoptotic activity of this molecule. Thus, QU can exert different effects (anti-/prooxidant) depending on exposure times and oxidative balance, and in particular on stores of GSH.     

Expression of metallothionein-I, -II, and -III in Alzheimer disease and animal models of neuroinflammation

In recent years it has become increasingly clear that the metallothionein (MT) family of proteins is important in neurobiology. MT-I and MT-II are normally dramatically up-regulated by neuroinflammation. Results for MT-III are less clear. MTs could also be relevant in human neuropathology. In Alzheimer disease (AD), a major neurodegenerative disease, clear signs of inflammation and oxidative stress were detected associated with amyloid plaques. Furthermore, the number of cells expressing apoptotic markers was also significantly increased in these plaques. As expected, MT-I and MT-II immunostaining was dramatically increased in cells surrounding the plaques, consistent with astrocytosis and microgliosis, as well as the increased oxidative stress elicited by the amyloid deposits. MT-III, in contrast, remained essentially unaltered, which agrees with some but not all studies, of AD. In situ hybridization results in a transgenic mouse model of AD amyloid deposits, the Tg2576 mouse, which expresses human Abeta precursor protein harboring the Swedish K670N/M671L mutations, are in accordance with results in human brains. Overall, these and other studies strongly suggest specific roles for MT-I, MT-II, and MT-III in brain physiology.     

Protocerebral mediodorsal A2' neurosecretory neurons in late pupae of yellow mealworm (Tenebrio molitor) after exposure to a static magnetic field

The activity of large dorsomedial protocerebral A2' neurosecretory neurons were investigated in late pupae of Tenebrio molitor L, which were exposed to a static magnetic field of 320 mT. Experimental groups were C: the control group which was kept at 5 meters from the magnet; CMF: pupae which were reared in control conditions and sacrificed on the eighth day of pupal stage (parents were kept in a magnetic field); and MF: pupae kept in a permanent magnetic field for eight days. Our results indicate the effects of a static magnetic field on the cytological characteristics and activity of large A2' neurosecretory neurons of Tenebrio molitor pupae.     

IL-22RA2 associates with multiple sclerosis and macrophage effector mechanisms in experimental neuroinflammation

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the CNS. Recent advances in whole-genome screening tools have enabled discovery of several MS risk genes, the majority of which have known immune-related functions. However, disease heterogeneity and low tissue accessibility hinder functional studies of established MS risk genes. For this reason, the MS model experimental autoimmune encephalomyelitis (EAE) is often used to study neuroinflammatory disease mechanisms. In this study, we performed high-resolution linkage analysis in a rat advanced intercross line to identify an EAE-regulating quantitative trait locus, Eae29, on rat chromosome 1. Eae29 alleles from the resistant strain both conferred milder EAE and lower production of proinflammatory molecules in macrophages, as demonstrated by the congenic line, DA.PVG-Eae29 (Dc1P). The soluble IL-22R α2 gene (Il-22ra2) lies within the Eae29 locus, and its expression was reduced in Dc1P, both in activated macrophages and splenocytes from immunized rats. Moreover, a single nucleotide polymorphism located at the end of IL-22RA2 associated with MS risk in a combined Swedish and Norwegian cohort comprising 5019 subjects, displaying an odds ratio of 1.26 (p = 8.0 × 10(-4)). IL-22 and its receptors have been implicated in chronic inflammation, suggesting that IL-22RA2 regulates a central immune pathway. Through a combined approach including genetic and immunological investigation in an animal model and large-scale association studies of MS patients, we establish IL-22RA2 as an MS risk gene.     

The life cycle and host specificity of Psychodiella sergenti n. sp. and Ps. tobbi n. sp. (Protozoa: Apicomplexa) in sand flies Phlebotomus sergenti and Ph. tobbi (Diptera: Psychodidae)

Two new gregarines in the recently erected genus Psychodiella (formerly Ascogregarina), Psychodiella sergenti n. sp. and Psychodiella tobbi n. sp., are described based on morphology and life cycle observations conducted on larvae and adults of their natural hosts, the sand flies Phlebotomus sergenti and Phlebotomus tobbi, respectively. The phylogenetic analyses inferred from small subunit ribosomal DNA (SSU rDNA) sequences indicate the monophyly of newly described species with Psychodiella chagasi. Ps. sergenti n. sp. and Ps. tobbi n. sp. significantly differ from each other in the life cycle and in the size of life stages. The sexual development of Ps. sergenti n. sp. (syzygy, formation of gametocysts and oocysts) takes place exclusively in blood-fed Ph. sergenti females, while the sexual development of Ps. tobbi n. sp. takes place also in males and unfed females of Ph. tobbi. The susceptibility of Phlebotomus perniciosus, Phlebotomus papatasi, Ph. sergenti, Ph. tobbi, and Phlebotomus arabicus to both gregarines was examined by exposing 1st instar larvae to parasite oocysts. High host specificity was observed, as both gregarines were able to fully develop and complete regularly the life cycle only in their natural hosts. Both gregarines are considered as serious pathogens in laboratory-reared colonies of Old World sand flies.     

Field growth characteristics of two aquatic carnivorous plants,Aldrovanda vesiculosa andUtricularia australis

Basic growth characteristics of two species of free-floating submerged carnivorous plants, the very rare and stenotopicAldrovanda vesiculosa and the very common and eurytopicUtricularia australis, were investigated in a 10/11-day field growth experiment within three nylon enclosures at two artificialAldrovanda sites in the T?eboň region, S Bohemia, Czech Republic, at the peak of a growing season. Growth ofAldrovanda was best at a meso-eutrophic site (biomass doubling time,T ₂, 8.4–10.7 days, mean growth of new leaf whorls 0.96 whorls days^?1, 1.6 developed branches per shoot) and slower at an oligo-mesotrophic site (T ₂ 17.2–21.5 days, growth of whorls 1.01 whorls days^?1, 0.1–0.5 branches per shoot). Growth ofUtricularia was similar at both sites (T ₂ 19.8–33.2 days or 9.1–16.8 days, growth of whorls 3.1 or 2.7 whorls days^?1, 1.5–2.1 or 0.8–1.4 developed branches per shoot at the former or latter site, respectively). Throughout the experiment, both species at the meso-eutrophic site allocated relatively more biomass to the production and growth of branches, than to that of new whorls. The results show thatAldrovanda, although usually considered as competitively weaker, can grow faster during the growing season peak thanUtricularia due to frequent branching and the subsequent rapid growth and separation of daughter shoots. Very rapid growth of rootless aquatic carnivorous plants in nutrient-poor habitats allows the consideration of ecophysiological adaptations that enable the plants to gain limiting mineral nutrients. These adaptations include carnivory, efficient nutrient reutilization from senescent shoots, and very high affinity for mineral nutrient uptake from water. Comparison of growth rates of rare and stenotopicA. vesiculosa and very common and eurytopicU. australis shows that differences in their rarity do not seem to be based on differences of growth rate.     

Experimental transmission of Leishmania tropica to hyraxes (Procavia capensis) by the bite of Phlebotomus arabicus

The ability of the sand fly Phlebotomus (Adlerius) arabicus to transmit Leishmania tropica was studied experimentally using hyraxes (Procavia capensis), natural reservoir hosts of the parasite. Sand flies became infected with L. tropica after feeding on a lesion of needle-inoculated hyrax. Moreover, P. arabicus fed with L. tropica promastigotes transmitted the parasite to hyraxes by bite during a second bloodmeal. Although the animals remained asymptomatic after infective sand fly bite, they were PCR positive and infectious for naive sand flies. We have thus demonstrated cyclical transmission of L. tropica by P. arabicus in hyraxes. This confirms experimentally the vectorial competence of P. (Adlerius) arabicus, and demonstrates that asymptomatic reservoir hosts are infectious to appropriate vectors.