Aging Studies Can Learn A Lot From A Bug’s Life
April 19, 2021 at 8:06 p.m.
By Max [email protected]
Aging itself is the most universal and unavoidable phenomenon in biology. More than 300 theories have been proposed to explain why organisms age and why they do so at different rates. Scientists still do not know or fully understand the causes of inter-individual variation in longevity and the tempo or rate of senescence (the process of deterioration with age) within species. Strangely, some animals hardly deteriorate as they get older.
Tortoises, are an example, their risk of death doesn’t seem to change with age in adulthood. These tortoises hardly age at all. The secret may be that their cells can divide more than twice as many times as human cells before they become senescent. There remains much more to be learned about human cells, however, and geriatrics is becoming an increasingly important specialty.
A number of studies reveal significant correlations between social factors, health and aging in human populations, but it is difficult to extract specific and causal relationships from clinical surveys. We do know that senescence results from a cumulative imbalance between damage and repair, and scientists are looking at insects for answers. Carefully selected groups of insects may help reveal whether and how social processes can reduce and increase repair.
Insects
Social insects, including ants, bees, wasps and termites, have been found to be particularly sensitive to changes in their social environment – they do not survive solitary confinement well, even when provided with enough food. These insects promise new ways to understand aging.
One reason is that many social insects live far longer than the more popular model organisms like fruit flies, mice and nematodes. The three species have been probed and tweaked for over a half century to learn what controls their life spans. In contrast to fruit flies, which have a life span of 13 weeks at most, and nematodes, a mere 18 days, honey bee queens live up to five years, and termite and ant queens more than 20.
Even more intriguing is the fact that aging in social insects is plastic, i.e., changing with social context. Queens and workers for social insects have very similar genomes, because all colony members are offsprings of one or several queens and while queens stay youthful through their long lives, workers age quickly and die fast. Within a colony, a worker’s job determines its life span, even though all workers are siblings. Scientists can rush, slow or even reverse aging in ants and bees simply by having them mate or changing their tasks.
Revealing the molecular mechanisms behind these strange phenomena may ultimately shed more light on aging in general, including humans. Job switches for bees also bring a different set of interactions with other members of the colony.
According to a recent article in Science, a bee’s social life plays an important role in its longevity. Social contact is also known to affect human physiological and mental health, and loneliness has been identified as a risk factor in cognitive decline. Other scientists have discovered that procreation extends the life spans of queens of certain ant species, honey bee queens, and termite queens and kings. In species where a limited number of workers in a colony can also reproduce, those that reproduce also live longer.
Social insect’s brains appear to benefit from sex. When Indian jumping ants lay eggs, their brain develops 40% more of a protective shell around key areas. A decline of the cells (ensheathing glia), that make up the shell is associated with aging in flies and cognitive loss in mice. If scientists knew what the ants use to control these cells it could point to similar mechanisms in humans.
Termites also have extraordinary longevity, but it is difficult to track their entire life. However, molecular studies have identified several genes that may be involved in longevity assurance. Further work is required to evaluate the biological function of these genes as they relate to longevity using the new genetic tools like gene editing now commonly in use. Gene editing enables scientists to disable specific genes and watch for effects on aging. Research has revealed that long lived queens of certain species produce antioxidant enzymes to counteract the oxidative stress that damages DNA. This ability is passed along to their offspring. Much work still needs to be done in this exciting field.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
Aging itself is the most universal and unavoidable phenomenon in biology. More than 300 theories have been proposed to explain why organisms age and why they do so at different rates. Scientists still do not know or fully understand the causes of inter-individual variation in longevity and the tempo or rate of senescence (the process of deterioration with age) within species. Strangely, some animals hardly deteriorate as they get older.
Tortoises, are an example, their risk of death doesn’t seem to change with age in adulthood. These tortoises hardly age at all. The secret may be that their cells can divide more than twice as many times as human cells before they become senescent. There remains much more to be learned about human cells, however, and geriatrics is becoming an increasingly important specialty.
A number of studies reveal significant correlations between social factors, health and aging in human populations, but it is difficult to extract specific and causal relationships from clinical surveys. We do know that senescence results from a cumulative imbalance between damage and repair, and scientists are looking at insects for answers. Carefully selected groups of insects may help reveal whether and how social processes can reduce and increase repair.
Insects
Social insects, including ants, bees, wasps and termites, have been found to be particularly sensitive to changes in their social environment – they do not survive solitary confinement well, even when provided with enough food. These insects promise new ways to understand aging.
One reason is that many social insects live far longer than the more popular model organisms like fruit flies, mice and nematodes. The three species have been probed and tweaked for over a half century to learn what controls their life spans. In contrast to fruit flies, which have a life span of 13 weeks at most, and nematodes, a mere 18 days, honey bee queens live up to five years, and termite and ant queens more than 20.
Even more intriguing is the fact that aging in social insects is plastic, i.e., changing with social context. Queens and workers for social insects have very similar genomes, because all colony members are offsprings of one or several queens and while queens stay youthful through their long lives, workers age quickly and die fast. Within a colony, a worker’s job determines its life span, even though all workers are siblings. Scientists can rush, slow or even reverse aging in ants and bees simply by having them mate or changing their tasks.
Revealing the molecular mechanisms behind these strange phenomena may ultimately shed more light on aging in general, including humans. Job switches for bees also bring a different set of interactions with other members of the colony.
According to a recent article in Science, a bee’s social life plays an important role in its longevity. Social contact is also known to affect human physiological and mental health, and loneliness has been identified as a risk factor in cognitive decline. Other scientists have discovered that procreation extends the life spans of queens of certain ant species, honey bee queens, and termite queens and kings. In species where a limited number of workers in a colony can also reproduce, those that reproduce also live longer.
Social insect’s brains appear to benefit from sex. When Indian jumping ants lay eggs, their brain develops 40% more of a protective shell around key areas. A decline of the cells (ensheathing glia), that make up the shell is associated with aging in flies and cognitive loss in mice. If scientists knew what the ants use to control these cells it could point to similar mechanisms in humans.
Termites also have extraordinary longevity, but it is difficult to track their entire life. However, molecular studies have identified several genes that may be involved in longevity assurance. Further work is required to evaluate the biological function of these genes as they relate to longevity using the new genetic tools like gene editing now commonly in use. Gene editing enables scientists to disable specific genes and watch for effects on aging. Research has revealed that long lived queens of certain species produce antioxidant enzymes to counteract the oxidative stress that damages DNA. This ability is passed along to their offspring. Much work still needs to be done in this exciting field.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
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