Gene prediction: the end of the beginning

A report from the conference entitled Genome Based Gene Structure Determination, Hinxton, UK, 1-2 June, 2000, organised by the European Bioinformatics Institute (EBI).     

Octopus senescence: the beginning of the end

Senescence is a normal stage of an octopus's life cycle that often occurs before death. Some of the following symptoms typify it: lack of feeding, retraction of skin around the eyes, uncoordinated movement, increased undirected activity, and white unhealing lesions on the body. There is inter- and intraspecific variability. Senescence is not a disease or a result of disease, although diseases can also be a symptom of it. Both males and females go through a senescent stage before dying-the males after mating, the females while brooding eggs and after the eggs hatch. There are many aspects of octopus senescence that have not yet been studied. This study discusses the ecological implications of senescence.     

Antioxidant defence mechanisms: From the beginning to the end (of the beginning)

When life first evolved on Earth, there was little oxygen in the atmosphere. Evolution of antioxidant defences must have been closely associated with the evolution of photosynthesis and of O₂-dependent electron transport mechanisms. Studies with mice lacking antioxidant defences confirm the important roles of MnSOD and transferrin in maintaining health, but show that glutathione peroxidase (GPX) and CuZnSOD are not essential for everyday life (at least in mice). Superoxide can be cytotoxic by several mechanisms: one is the formation of hydroxyl radicals. There is good evidence that OH^· formation occurs in vivo. Other important antioxidants may include thioredoxin, and selenoproteins other than GPX. Nitric oxide may be an important antioxidant in the vascular system. Diet-derived antioxidants are important in maintaining human health, but recent studies employing “biomarkers” of oxidative DNA damage are questioning the “antioxidant” roles of β-carotene and ascorbate. An important area of future research will be elucidation of the reasons why levels of steady-state oxidative damage to DNA and lipids vary so much between individuals, and their predictive value for the later development of human disease.     

Antioxidant defence mechanisms: From the beginning to the end (of the beginning)

When life first evolved on Earth, there was little oxygen in the atmosphere. Evolution of antioxidant defences must have been closely associated with the evolution of photosynthesis and of O₂-dependent electron transport mechanisms. Studies with mice lacking antioxidant defences confirm the important roles of MnSOD and transferrin in maintaining health, but show that glutathione peroxidase (GPX) and CuZnSOD are not essential for everyday life (at least in mice). Superoxide can be cytotoxic by several mechanisms: one is the formation of hydroxyl radicals. There is good evidence that OH^· formation occurs in vivo. Other important antioxidants may include thioredoxin, and selenoproteins other than GPX. Nitric oxide may be an important antioxidant in the vascular system. Diet-derived antioxidants are important in maintaining human health, but recent studies employing “biomarkers” of oxidative DNA damage are questioning the “antioxidant” roles of β-carotene and ascorbate. An important area of future research will be elucidation of the reasons why levels of steady-state oxidative damage to DNA and lipids vary so much between individuals, and their predictive value for the later development of human disease.     

Messenger RNA degradation: beginning at the end

The mechanisms responsible for mRNA decay in mammalian cells, and how specific sequence elements accelerate decay, are unknown. Recent work indicates that 'ARE' instability elements recruit the exosome to promote rapid 3'-to-5' degradation of the mRNA.     

Planarian regeneration: its end is its beginning

Why does regeneration take place in some animals but not others? Increased understanding of gene function is required to dissect the genetics, cell biology, and physiological aspects that make regeneration possible. An unlikely model animal, the planarian Schmidtea mediterranea, is proving valuable in this endeavor.