Search results
Results from the WOW.Com Content Network
A well-established example of bacterial aging is Caulobacter crescentus.This bacterium begins its life as a motile swarmer cell. Once it has found a suitable substrate, the swarmer cell will differentiate into a non-motile stalked cell.The asymmetrically dividing cells then show signs of detrimental genetic variation as they divide. [9]
Senescence (/ s ɪ ˈ n ɛ s ə n s /) or biological aging is the gradual deterioration of functional characteristics in living organisms. Whole organism senescence involves an increase in death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle .
Why does biological aging occur? There are a number of hypotheses as to why senescence occurs including those that it is programmed by gene expression changes and that it is the accumulative damage of biological structures, particularly damage to DNA .
Fungal-bacterial endosymbiosis encompasses the mutualistic relationship between a fungus and intracellular bacteria species residing within the fungus. Many examples of endosymbiotic relationships between bacteria and plants, algae and insects exist and have been well characterized, however fungal-bacteria endosymbiosis has been less well described.
Williams noted that senescence may be causing many deaths even if animals are not 'dying of old age.' [1] He began his hypothesis with the idea that ageing can cause earlier senescence due to the competitive nature of life. Even a small amount of ageing can be fatal; hence natural selection does indeed care and ageing is not cost-free. [17]
Senescence and SASP can also occur in post-mitotic cells, notably neurons. [12] The SASP in senescent neurons can vary according to cell type, the initiator of senescence, and the stage of senescence. [12] An online SASP Atlas serves as a guide to the various types of SASP. [8]
Negligible senescence is a term coined by biogerontologist Caleb Finch to denote organisms that do not exhibit evidence of biological aging , such as measurable reductions in their reproductive capability, measurable functional decline, or rising death rates with age. [1]
Saccharomyces cerevisiae (/ ˌ s ɛr ə ˈ v ɪ s i. iː /) (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times.