Crescimento micelial e s��ntese de prote��nas de choque t��rmico em tr��s isolados de fungos ectomicorr��zicos sob condi����es de temperaturas supra-��timas

A s��ntese de prote��nas de choque t��rmico �� uma altera����o fisiol��gica transiente na c��lula de organismos expostos a temperaturas supra-��timas. A resposta fisiol��gica ao choque t��rmico �� dependente, particularmente, do tipo de c��lula e da capacidade dos organismos em responder ��s altera����es do meio. O presente trabalho teve como objetivo avaliar o crescimento micelial e a s��ntese de prote��nas de choque t��rmico de dois isolados de Pisolithus sp. (RV82 e RS24) e de um isolado de Paxillus involutus em temperaturas supra-��timas. No trabalho, foram feitas an��lises de crescimento micelial em placa de Petri com meio apropriado para o crescimento sob condi����es de temperaturas subletais, letais e de choque t��rmico. As prote��nas nos mic��lios dos isolados foram marcadas com amino��cido radioativo (��H-leucina), e a radioatividade, quantificada em solu����o de cintila����o. A s��ntese das prote��nas de choque t��rmico (HSPs) foi avaliada em gel de poliacrilamida (SDS-PAGE e 2D-PAGE). Demonstrou-se, com ��H-leucina, que os fungos ectomicorr��zicos apresentaram respostas diferenciadas em rela����o ao crescimento micelial quando expostos a temperaturas supra-��timas. Os dois isolados de Pisolithus sp., RS24 e RV82, mostraram-se mais tolerantes a altas temperaturas, quando comparado ao isolado de P. involutus. Os isolados de Pisolithus sp. diferem quanto �� s��ntese de prote��nas de estresse, com a s��ntese de HSPs de alta e de baixa massa molecular. Em resposta ao choque t��rmico, o isolado RV82 sintetizou prote��nas putativas dos grupos HSP70, HSP28 e HSP26 e as sHSPs (15-18 kDa), enquanto o isolado RS24 sintetizou as dos grupos HSP86, HSP60, HSP55 e HSP35 e as sHSPs (12-18 kDa). A baixa toler��ncia a temperaturas elevadas do isolado de P. involutus foi atribu��da �� aus��ncia de s��ntese de prote��nas putativas do grupo HSPs em condi����es de choque t��rmico. Os resultados sugerem que os isolados de fungos ectomicorr��zicos diferem quanto ao mecanismo de indu����o de termotoler��ncia.

Olfactory cues potentiate learning of distant visuospatial information

The influence of proximal olfactory cues on place learning and memory was tested in two different spatial tasks. Rats were trained to find a hole leading to their home cage or a single food source in an array of petri dishes. The two apparatuses differed both by the type of reinforcement (return to the home cage or food reward) and the local characteristics of the goal (masked holes or salient dishes). In both cases, the goal was in a fixed location relative to distant visual landmarks and could be marked by a local olfactory cue. Thus, the position of the goal was defined by two sets of redundant cues, each of which was sufficient to allow the discrimination of the goal location. These experiments were conducted with two strains of hooded rats (Long-Evans and PVG), which show different speeds of acquisition in place learning tasks. They revealed that the presence of an olfactory cue marking the goal facilitated learning of its location and that the facilitation persisted after the removal of the cue. Thus, the proximal olfactory cue appeared to potentiate learning and memory of the goal location relative to distant environmental cues. This facilitating effect was only detected when the expression of spatial memory was not already optimal, i.e., during the early phase of acquisition. It was not limited to a particular strain.

Liitepartikkelien vokaalisointusuhteita suomen murteissa

Summary: Non-harmonic enclitic particles in Finnish dialects

Management of nanomaterials safety in research environment

Despite numerous discussions, workshops, reviews and reports about responsible development of nanotechnology, information describing health and environmental risk of engineered nanoparticles or nanomaterials is severely lacking and thus insufficient for completing rigorous risk assessment on their use. However, since preliminary scientific evaluations indicate that there are reasonable suspicions that activities involving nanomaterials might have damaging effects on human health; the precautionary principle must be applied. Public and private institutions as well as industries have the duty to adopt preventive and protective measures proportionate to the risk intensity and the desired level of protection. In this work, we present a practical, 'user-friendly' procedure for a university-wide safety and health management of nanomaterials, developed as a multi-stakeholder effort (government, accident insurance, researchers and experts for occupational safety and health). The process starts using a schematic decision tree that allows classifying the nano laboratory into three hazard classes similar to a control banding approach (from Nano 3 - highest hazard to Nano1 - lowest hazard). Classifying laboratories into risk classes would require considering actual or potential exposure to the nanomaterial as well as statistical data on health effects of exposure. Due to the fact that these data (as well as exposure limits for each individual material) are not available, risk classes could not be determined. For each hazard level we then provide a list of required risk mitigation measures (technical, organizational and personal). The target 'users' of this safety and health methodology are researchers and safety officers. They can rapidly access the precautionary hazard class of their activities and the corresponding adequate safety and health measures. We succeed in convincing scientist dealing with nano-activities that adequate safety measures and management are promoting innovation and discoveries by ensuring them a safe environment even in the case of very novel products. The proposed measures are not considered as constraints but as a support to their research. This methodology is being implemented at the Ecole Polytechnique de Lausanne in over 100 research labs dealing with nanomaterials. It is our opinion that it would be useful to other research and academia institutions as well. [Authors]

Optimization of centrifugal separation of ��-lactalbumin and ������-lactoglobulin

Selostus: ��-lactalbumiinin ja ������-lactoglobuliinin sentrifugointierotuksen optimointi