Prion protein interaction with soil humic substances: environmental implications

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative disorders caused by prions. Animal TSE include scrapie in sheep and goats, and chronic wasting disease (CWD) in cervids. Effective management of scrapie in many parts of the world, and of CWD in North American deer population is complicated by the persistence of prions in the environment. After shedding from diseased animals, prions persist in soil, withstanding biotic and abiotic degradation. As soil is a complex, multi-component system of both mineral and organic components, it is important to understand which soil compounds may interact with prions and thus contribute to disease transmission. Several studies have investigated the role of different soil minerals in prion adsorption and infectivity; we focused our attention on the interaction of soil organic components, the humic substances (HS), with recombinant prion protein (recPrP) material. We evaluated the kinetics of recPrP adsorption, providing a structural and biochemical characterization of chemical adducts using different experimental approaches. Here we show that HS act as potent anti-prion agents in prion infected neuronal cells and in the amyloid seeding assays: HS adsorb both recPrP and prions, thus sequestering them from the prion replication process. We interpreted our findings as highly relevant from an environmental point of view, as the adsorption of prions in HS may affect their availability and consequently hinder the environmental transmission of prion diseases in ruminants

Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)

Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem

Effort-related functions of nucleus accumbens dopamine and associated forebrain circuits

Background Over the last several years, it has become apparent that there are critical problems with the hypothesis that brain dopamine (DA) systems, particularly in the nucleus accumbens, directly mediate the rewarding or primary motivational characteristics of natural stimuli such as food. Hypotheses related to DA function are undergoing a substantial restructuring, such that the classic emphasis on hedonia and primary reward is giving way to diverse lines of research that focus on aspects of instrumental learning, reward prediction, incentive motivation, and behavioral activation. Objective The present review discusses dopaminergic involvement in behavioral activation and, in particular, emphasizes the effort-related functions of nucleus accumbens DA and associated forebrain circuitry. Results The effects of accumbens DA depletions on food-seeking behavior are critically dependent upon the work requirements of the task. Lever pressing schedules that have minimal work requirements are largely unaffected by accumbens DA depletions, whereas reinforcement schedules that have high work (e.g., ratio) requirements are substantially impaired by accumbens DA depletions. Moreover, interference with accumbens DA transmission exerts a powerful influence over effort-related decision making. Rats with accumbens DA depletions reallocate their instrumental behavior away from food-reinforced tasks that have high response requirements, and instead, these rats select a less-effortful type of food-seeking behavior. Conclusions Along with prefrontal cortex and the amygdala, nucleus accumbens is a component of the brain circuitry regulating effort-related functions. Studies of the brain systems regulating effort-based processes may have implications for understanding drug abuse, as well as energy-related disorders such as psychomotor slowing, fatigue, or anergia in depression

Dehalogennation of Halokanes by Rhodococuus-Erythropolis Y2

Rhodococcus erythropolis Y2 produced two types of dehalogenase: a hydrolytic enzyme, that is an halidohydrolase, which was induced by C-3 to C-6 1-haloalkane substrates, and at least one oxygenase-type dehalogenase induced by C-7 to C-16 1-haloalkanes and n-alkanes. The oxygenase-type activity dehalogenated C-4 to C-18 1-chloroalkanes with an optimum activity towards 1-chlorotetradecane, The halidohydrolase catalysed the dehalogenation of a wide range of 1- and alpha,omega-disubstituted haloalkanes and alpha,omega-substituted haloalcohols. In resting cell suspensions of hexadecane-grown R. erythropolis Y2 the oxygenase-type dehalogenase had a specific activity of 12.9 mU (mg protein)(-1) towards 1-chlorotetradecane (3.67 mU mg(-1) towards 1-chlorobutane) whereas the halidohydrolase in 1-chlorobutane-grown batch cultures had a specific activity of 44 mU (mg protein)(-1) towards 1-chlorobutane. The significance of the two dehalogenase systems in a single bacterial strain is discussed in terms of their contribution to the overall catabolic potential of the organism

Importância da detecção de patologias do desenvolvimento na anóxia neonatal e da intervenção fisioterápica

O objetivo deste estudo foi verificar o desenvolvimento neuropsicomotor e a necessidade de estimulação nos 27 casos com recuperação parcial e diagnóstico de anóxia neonatal atendidos no ano de 1988 na UTI de Recém-Nascidos (RN) do Hospital Universitário de Santa Maria-RS. Foi relacionado o diagnóstico de patologia neurológica e a indicação fisioterápica no momento da alta hospitalar. Os RN foram avaliados segundo abordagem neuroevolutiva em visitas domiciliares a 10 casos. Os resultados revelaram a necessidade de intervenção fisioterápica nos casos de anóxia neonatal