The relationship between prion propagation, generation RG7420 of neurotoxic species and clinical onset has remained obscure. Prion incubation periods in experimental animals are known to vary inversely with expression level of cellular prion

protein. Here we demonstrate that prion propagation in brain proceeds via two distinct phases: a clinically silent exponential phase not rate-limited by prion protein concentration which rapidly reaches a maximal prion titre, followed by a distinct switch to a plateau phase. The latter determines time to clinical onset in a manner inversely proportional to prion protein concentration. These findings demonstrate an uncoupling of infectivity and toxicity. We suggest that prions themselves are not neurotoxic but catalyse the formation of such species from PrPC. Production of neurotoxic species is triggered when prion propagation saturates, leading to a switch from autocatalytic production of infectivity (phase 1) to a toxic

(phase 2) pathway.”
“To determine the apicultural value of Vigna unguiculata (L.) Walp. (Fabaceae) check details and evaluate the Apis mellifera adansonii Latreille (Hymenoptera: Apidae) activity on its pod and seed yields, the bee foraging and pollinating activities were studied in Ngaoundere. The experiment was carried out within the University of Ngaoundere Campus on 210 flowers differentiated in two lots, based on the protection/or not of plant inflorescences against insect visits. The bee’s seasonal rhythm of activity, its foraging behaviour on flowers, the fructification rate, the number and dry weight of seeds/pod, the percentage of normal seeds/pod, and the pod length were evaluated. Results show that A. m. adansonii foraged on plants throughout the whole blooming period. Worker bees intensively and preferably harvested nectar. The greatest mean number of workers foraging simultaneously was 500 per 1000 flowers. The mean foraging speed was 8.67 flowers/min. These findings

allow the classification of V. unguiculata as a highly nectariferous bee plant. The number and dry weight of seed/pod, the pod length and the percentage of normal seeds/pod from unprotected selleck compound flowers were significantly higher than those of flowers protected from insects. The fructification rates were 62 and 48%, while the percentages of healthly seeds were 97.61 and 76.17%, respectively in unprotected and protected inflorescences. The installation of A. m. adansonii colonies close to V. unguiculata field could be recommended to improve its pods and seeds production in the region.”
“The growing number of bacterial strains resistant to conventional antibiotics has become a serious medical problem in recent years. 432 marine sponges are a rich source of bioactive compounds, and many species can be useful for the development of new antimicrobial drugs. This study reports the in vitro screening of marine sponges in the search for novel substances against antibiotic-resistant bacteria.