ABSTRACT
Water is usually thought to be required for the living state, but several organisms are capable of surviving complete dehydration (anhydrobiotes). Elucidation of the mechanisms of tolerance against dehydration may lead to development of new methods for preserving biological materials that do not normally support drying, which is of enormous practical importance in industry, in clinical medicine as well as in agriculture. One of the molecular mechanisms of damage leading to death in desiccation-sensitive cells upon drying is free-radical attack to phospholipids, DNA and proteins. This review aims to summarize the strategies used by anhydrobiotes to cope with the danger of oxygen toxicity and to present our recent results about the importance of some antioxidant defense systems in the dehydration tolerance of Saccharomyces cerevisiae, a usual model in the study of stress response.
Subject(s)
Dehydration , Oxidative Stress , Saccharomyces cerevisiae/physiology , Animals , Antioxidants/metabolism , Catalase/metabolism , DNA Damage , Glutathione/metabolism , Lipid Metabolism , Lipid Peroxidation , Proteins/metabolism , Reactive Oxygen Species , Superoxide Dismutase/metabolism , Trehalose/metabolismABSTRACT
New Zealand White rabbits fed a low-level cholesterol-enriched diet (0.1%) were used to study and characterize a possible model of experimental atherogenesis. For the determination of the degree of atherosclerosis, more consistent and reproducible morphometric methods were used. Simultaneously the influence of plasma cholesterol levels on vascular noradrenaline content was studied. The effect of a new lipid-regulating drug (0.1% L 44-0, the N-oxide of a nicotinic acid derivative) on analyzed parameters was studied as well. This study suggests that the low-level cholesterol-enriched diet is atherogenic, with macroscopically detectable lesions of atherosclerosis becoming apparent by week 12 of the study. The same diet increases the vascular noradrenaline content in the renal artery and in the femoral artery and vein; however, it does not influence that content in the carotid and mesenteric arteries. L 44-0 counteracts most of the observed effects.
Subject(s)
Arteriosclerosis/physiopathology , Blood Vessels/chemistry , Cholesterol, Dietary/metabolism , Cyclic N-Oxides/pharmacology , Disease Models, Animal , Lipids/analysis , Nicotinic Acids/pharmacology , Norepinephrine/metabolism , Animals , Arteriosclerosis/chemically induced , Cholesterol/analysis , Evaluation Studies as Topic , Hyperlipidemias/chemically induced , Hyperlipidemias/metabolism , Lipoproteins, HDL/analysis , Male , Rabbits , Triglycerides/analysisABSTRACT
Foi analisado o conteudo semantico das respostas de pesquisadores (n=17) e leigos (n=28) em resposta a questao: 'O que e pesquisa?' Obteve-se fidedignidade alta para as categorias de analise. Os pesquisadores destacaram as dimensoes: metodo; investigacao e construcao de teoria; os leigos destacaram investigacao e objeto. Nao foi significante a correlacao entre as opinioes de leigos e de pesquisadores.
