Phenoptosis

Phenoptosis (pheno – showing or demonstrating, ptosis – programmed death, "falling off"), designated by V.P. Skulachev in 1999, signifies the phenomenon of programmed death of an organism, i.e. that an organism's genes include features that under certain circumstances will cause the organism to rapidly degenerate and die off. Recently this has been referred to as "fast phenoptosis" as aging is being explored as "slow phenoptosis".[1] Phenoptosis is a common feature of living species, whose ramifications for humans is still being explored.

Evolutionary significance

Inside of our bodies, worn-out, ineffective cells are dismantled and recycled for the greater good of the whole organism. This is a process called apoptosis. It is believed that phenoptosis is an evolutionary mechanism that culls out the damaged, aged, infectious, or those in direct competition with their own offspring[2] for the good of the species. The elimination of parts detrimental to the organism or individuals detrimental to the species has been deemed "The samurai law of biology" – it is better to die than to be wrong.[3] Stress-induced, acute, or fast phenoptosis is the rapid deterioration of an organism induced by a life event such as breeding. Elimination of the parent provides space for fitter offspring. As a species this has been advantageous particularly to species that die immediately after spawning.[2] Age-induced, soft, or slow phenoptosis is the slow deterioration and death of an organism due to accumulated stresses over long periods of time. In short, it has been proposed that aging, heart disease, cancer, and other age related ailments are means of phenoptosis. "Death caused by aging clears the population of ancestors and frees space for progeny carrying new useful traits."[3] It has also been proposed that age provides a selective advantage to brains over brawn.[4] An example made by V. P. Skulachev provides that of two hares, one faster and one smarter, the faster hare may have a selective advantage in youth but as aging occurs and muscles deteriorate it is the smarter hare that now has the selective advantage.

Examples in nature

E. coli – programmed death is initiated by infection by phage. This prevents further spread of phage to the remaining population.[5]

Saccharomyces cerevisiae – Under stress the yeast mitochondria produce reactive oxygen species ROS, leading to loss of membrane potential within the mitochondria and death of the cell.[6]

Amoeba Dictyostelium – Under stress amoeba form multicellular fruiting bodies. The better nourished cells differentiate into spores. The less healthy cells differentiate into the stalks of the fruiting body. After maturation of the spores, the stalk cells undergo phenoptosis.[7]

Nematode Caenorhabditis elegans – Under normal conditions Caenorhabditis elegans display a normal aging life cycle. However, if there is increased stress after breeding they undergo phenoptosis, like in yeast, induced by the mitochondria.[8]

Mayfly – Adult mayflies have no functional mouth and die from malnutrition.[2]

Praying mantis – The male praying mantis ejaculates only after being decapitated by the female.[9]

Mite Adactylidium – The initial food source of Adactylidium mite larvae is the body tissues of their mother resulting in her death.[6]

Squid – Some male squid die immediately after mating. This provides an abundant food source for those predators that would prey on the eggs.[10]

marsupial mice – Males die two weeks after reproducing from an overabundance of their own pheromones.[6]

Salmon – Die soon after spawning.[11]

Septic shock – Severe infection by pathogens often results in death by sepsis. Sepsis, however, is not a result of toxins activated by the pathogen, rather it is directed by the organism itself. Similar to phenoptosis of E. coli, this has been suggested to be a means to separate dangerously infected individuals from healthy ones.[5]

Proposed mechanisms

Mitochondrial ROS – The production of ROS by the mitochondria. This causes oxidative damage to the inner compartment of the mitochondria and destruction of the mitochondria.[5]

Clk1 gene – the gene thought to be responsible to aging due to mitochondrial ROS.[12]

EF2 kinase – Blocks phosphorylation of elongation factor 2 thus blocking protein synthesis.[13]

Glucocorticoid regulation – A common route for phenoptosis is breakdown of glucocorticoid regulation and inhibition, leading to massive excess of these corticosteroids in the body.[3]

Other examples

Robert Sapolsky discusses phenoptosis in his book Why Zebras Don't Get Ulcers, 3rd Ed., p. 245-247. He states that:

"If you catch salmon right after they spawn... you find they have huge adrenal glands, peptic ulcers, and kidney lesions, their immune systems have collapsed... [and they] have stupendously high glucocorticoid concentrations in their bloodstreams. When salmon spawn, regulation of their glucocortocoid secretion breaks down... But is the glucocorticoid excess really responsible for their death? Yup. Take a salmon right after spawning, remove its adrenals, and it will live for a year afterward.
"The bizarre thing is that this sequence... not only occurs in five species of salmon, but also among a dozen species of Australian marsupial mice... Pacific salmon and marsupial mice are not close relatives. At least twice in evolutionary history, completely independently, two very different sets of species have come up with the identical trick: if you want to degenerate very fast, secrete a ton of glucocorticoids."

See also

References

  1. ^ Skulachev, V.P. (November 1997). "Organism's Aging is a Special Biological Function Rather than a Result of Breakdown of a Complex Biological System: Biochemical Support of Weismann's Hypothesis". Biokhimiya. 62 (12): 1191–1195. PMID 9467841.
  2. ^ a b c Weismann, A (1889). Essays upon Heredity and Kindred Bio_. Oxford: Clarendon Press. p. 23. ISBN 978-1172574988.
  3. ^ a b c Skulachev, VP (Apr 2002). "Programmed death phenomena: from organelle to organism". Ann N Y Acad Sci. 959: 214–237. doi:10.1111/j.1749-6632.2002.tb02095.x. PMID 11976198.
  4. ^ Skulachev, VP (November 2011). "Aging as a particular case of phenoptosis, the programmed death of an organism (A response to Kirkwood and Melov "On the programmed/non-programmed nature of ageing within the life history")". Aging. 3 (11): 1120–1123. doi:10.18632/aging.100403. PMC 3249457. PMID 22146104.
  5. ^ a b c Skulachev, VP (December 1999). "Phenoptosis: programmed death of an organism". Biokhimiya. 64 (12): 1418–1426. PMID 10648966.
  6. ^ a b c Severin, FF; Skulachev, VP (2011). "Programmed Cell Death as a Target to Interrupt the Aging Program". Advances in Gerontology. 1 (1): 16–27. doi:10.1134/S2079057011010139.
  7. ^ Thompson, CR; Kay, RR (November 2000). "Cell-FateChoice in Dictyostelium: Intrinsic Biases Modulate Sensitivity to DIF Signaling". Developmental Biology. 227 (1): 56–64. doi:10.1006/dbio.2000.9877. PMID 11076676.
  8. ^ Pestov, NB; Shakhparonov, M.; Korneenko, T. (Sep–Oct 2011). "Matricide in Caenorhabditis elegans as an example of programmed death of an animal organism: The role of mitochondrial oxidative stress". Russian Journal of Bioorganic Chemistry. 37 (5): 705–710. doi:10.1134/S106816201105013X. PMID 22332368.
  9. ^ Dawkins, R (1976). The Selfish Gene. Oxford: Oxford Univ.Press. ISBN 978-0192860927.
  10. ^ Nesis, K (1997). "A Cruel Love of Squids". The Russian Science:To Withstand and Resurrect: 358–365.
  11. ^ Kirkwood, TB; Cremer T (1982). "Cytogerontology since 1881: a reappraisal of August Weismann and a review of modern progress". Hum Genet. 60 (2): 101–121. doi:10.1007/BF00569695. PMID 7042533.
  12. ^ Liu, X; Jiang, N.; Bigras, E.; Shoubridge, E.; Hekimi, S. (15 Oct 2005). "Evolutionary conservation of the clk-1-dependent mechanism of longevity: loss of mclk1 increases cellular fitness and lifespan in mice". Genes Dev. 19 (20): 2424–34. doi:10.1101/gad.1352905. PMC 1257397. PMID 16195414.
  13. ^ Holley, CL; Michael R. Olson; Daniel A. Colón-Ramos; Sally Kornbluth (June 2002). "Reaper eliminates IAP proteins through stimulated IAP degradation and generalized translational inhibition". Nat Cell Biol. 4 (6): 439–444. doi:10.1038/ncb798. PMC 2713440. PMID 12021770.
Algor mortis

Algor mortis (Latin: algor—coldness; mortis—of death), the second stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body acclimates to the warmer environment. External factors can have a significant influence.

The term was first used by Dowler in 1849. The first published measurements of the intervals of temperature after death were done by Dr John Davey in 1839.

Dead on arrival

Dead on arrival (DOA), also dead in the field and brought in dead (BID), indicates that a patient was found to be already clinically dead upon the arrival of professional medical assistance, often in the form of first responders such as emergency medical technicians, paramedics, or police.

In some jurisdictions, first responders must consult verbally with a physician before officially pronouncing a patient deceased, but once cardiopulmonary resuscitation is initiated, it must be continued until a physician can pronounce the patient dead.

Death hoax

A death hoax is a deliberate or confused report of someone's death that turns out to be incorrect and murder rumors. In some cases it might be because the person has intentionally faked death.

Death messenger

Death messengers, in former times, were those who were dispatched to spread the news that an inhabitant of their city or village had died. They were to wear unadorned black and go door to door with the message, "You are asked to attend the funeral of the departed __________ at (time, date, and place)." This was all they were allowed to say, and were to move on to the next house immediately after uttering the announcement. This tradition persisted in some areas to as late as the mid-19th century.

Death pose

Dinosaur and bird fossils are frequently found in a characteristic posture consisting of head thrown back, tail extended, and mouth wide open. The cause of this posture—sometimes called a "death pose"—has been a matter of scientific debate. Traditional explanations ranged from strong ligaments in the animal's neck desiccating and contracting to draw the body into the pose, to water currents randomly arranging the remains in the position.Faux and Padian suggested in 2007 that the live animal was suffering opisthotonus during its death throes, and that the pose is not the result of any post-mortem process at all. They also reject the idea of water as responsible for randomly arranging the bodies in a "death pose", as different parts of the body and the limbs can be in different directions, which they found unlikely to be the result of moving water. They also found that the claim that drying out of ligaments would make the position does not seem believable either.

Alicia Cutler and colleagues from Brigham Young University in Provo, Utah, think it is related to water. In 2012, paleontologists Achim G. Reisdorf and Michael Wuttke published a study regarding death poses. According to the conclusions of this study, the so-called "opisthotonic posture" is not the result of a cerebral illness creating muscle spasms, and also not of a rapid burial. Rather, peri-mortem submersion resulted in buoyancy that enabled the Ligamentum elasticum to pull the head and tail back.

Death rattle

Terminal respiratory secretions (or simply terminal secretions), known colloquially as a death rattle, are sounds often produced by someone who is near death as a result of fluids such as saliva and bronchial secretions accumulating in the throat and upper chest. Those who are dying may lose their ability to swallow and may have increased production of bronchial secretions, resulting in such an accumulation. Usually, two or three days earlier, the symptoms of approaching death can be observed as saliva accumulates in the throat, making it very difficult to take even a spoonful of water. Related symptoms can include shortness of breath and rapid chest movement. While death rattle is a strong indication that someone is near death, it can also be produced by other problems that cause interference with the swallowing reflex, such as brain injuries.It is sometimes misinterpreted as the sound of the person choking to death, or alternatively, that they are gargling.

Dignified death

Dignified death is a somewhat elusive concept often related to suicide. One factor that has been cited as a core component of dignified death is maintaining a sense of control. Another view is that a truly dignified death is an extension of a dignified life. There is some concern that assisted suicide does not guarantee a dignified death, since some patients may experience complications such as nausea and vomiting. There is some concern that age discrimination denies the elderly a dignified death.

Dysthanasia

In medicine, dysthanasia means "bad death" and is considered a common fault of modern medicine.Dysthanasia occurs when a person who is dying has their biological life extended through technological means without regard to the person's quality of life. Technologies such as an implantable cardioverter defibrillator, artificial ventilation, ventricular assist devices, and extracorporeal membrane oxygenation can extend the dying process.

Dysthanasia is a term generally used when a person is seen to be kept alive artificially in a condition where, otherwise, they cannot survive; sometimes for some sort of ulterior motive. The term was used frequently in the investigation into the death of Formula One driver Ayrton Senna in 1994.

Fan death

Fan death is a well-known superstition in Korean culture, where it is thought that running an electric fan in a closed room with unopened or no windows will prove fatal. Despite no concrete evidence to support the concept, belief in fan death persists to this day in Korea, and also to a lesser extent in Japan.

Funeral director

A funeral director, also known as an undertaker (British English) or mortician (American English), is a professional involved in the business of funeral rites. These tasks often entail the embalming and burial or cremation of the dead, as well as the arrangements for the funeral ceremony (although not the directing and conducting of the funeral itself unless clergy are not present). Funeral directors may at times be asked to perform tasks such as dressing (in garments usually suitable for daily wear), casketing (placing the human body in the coffin), and cossetting (applying any sort of cosmetic or substance to the best viewable areas of the corpse for the purpose of enhancing its appearance). A funeral director may work at a funeral home or be an independent employee.

Lazarus sign

The Lazarus sign or Lazarus reflex is a reflex movement in brain-dead or brainstem failure patients, which causes them to briefly raise their arms and drop them crossed on their chests (in a position similar to some Egyptian mummies). The phenomenon is named after the Biblical figure Lazarus of Bethany, whom Jesus raised from the dead in the Gospel of John.

Megadeath

Megadeath (or megacorpse) is one million human deaths, usually caused by a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.

Necronym

A necronym (from the Greek words νεκρός, nekros, "dead" and ὄνομα ónoma, "name") is a reference to, or name of, a person who has died. Many cultures have taboos and traditions associated with referring to such a person. These vary from the extreme of never again speaking the person's real name, often using some circumlocution instead, to the opposite extreme of commemorating it incessantly by naming other things or people after the deceased.

For instance, in some cultures it is common for a newborn child to receive the name (a necronym) of a relative who has recently died, while in others to reuse such a name would be considered extremely inappropriate or even forbidden. While this varies from culture to culture, the use of necronyms is quite common.

Necrophobia

Necrophobia is a specific phobia which is the irrational fear of dead things (e.g., corpses) as well as things associated with death (e.g., coffins, tombstones, funerals, cemeteries). With all types of emotions, obsession with death becomes evident in both fascination and objectification. In a cultural sense, necrophobia may also be used to mean a fear of the dead by a cultural group, e.g., a belief that the spirits of the dead will return to haunt the living.Symptoms include: shortness of breath, rapid breathing, irregular heartbeat, sweating, dry mouth and shaking, feeling sick and uneasy, psychological instability, and an altogether feeling of dread and trepidation. The sufferer may feel this phobia all the time. The sufferer may also experience this sensation when something triggers the fear, like a close encounter with a dead animal or the funeral of a loved one or friend. The fear may have developed when a person witnessed a death, or was forced to attend a funeral as a child. Some people experience this after viewing frightening media.The fear can manifest itself as a serious condition. Treatment options include medication and therapy.The word necrophobia is derived from the Greek nekros (νεκρός) for "corpse" and the Greek phobos (φόβος) for "fear".

Obituary

An obituary (obit for short) is a news article that reports the recent death of a person, typically along with an account of the person's life and information about the upcoming funeral. In large cities and larger newspapers, obituaries are written only for people considered significant. In local newspapers, an obituary may be published for any local resident upon death. A necrology is a register or list of records of the deaths of people related to a particular organization, group or field, which may only contain the sparsest details, or small obituaries. Historical necrologies can be important sources of information.

Two types of paid advertisements are related to obituaries. One, known as a death notice, omits most biographical details and may be a legally required public notice under some circumstances. The other type, a paid memorial advertisement, is usually written by family members or friends, perhaps with assistance from a funeral home. Both types of paid advertisements are usually run as classified advertisements.

Pallor mortis

Pallor mortis (Latin: pallor "paleness", mortis "of death"), the first stage of death, is an after-death paleness that occurs in those with light/white skin.

Post-mortem interval

Post-mortem interval (PMI) is the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it. This also can refer to the stage of decomposition of the body.

Rigor mortis

Rigor mortis (Latin: rigor "stiffness", mortis "of death"), or postmortem rigidity, is the third stage of death. It is one of the recognizable signs of death, characterized by stiffening of the limbs of the corpse caused by chemical changes in the muscles postmortem. In humans, rigor mortis can occur as soon as four hours after death.

Skeletonization

Skeletonization refers to the final stage of decomposition, during which the last vestiges of the soft tissues of a corpse or carcass have decayed or dried to the point that the skeleton is exposed. By the end of the skeletonization process, all soft tissue will have been eliminated, leaving only disarticulated bones. In a temperate climate, it usually requires three weeks to several years for a body to completely decompose into a skeleton, depending on factors such as temperature, humidity, presence of insects, and submergence in a substrate such as water. In tropical climates, skeletonization can occur in weeks, while in tundra areas, skeletonization may take years or may never occur, if subzero temperatures persist. Natural embalming processes in peat bogs or salt deserts can delay the process indefinitely, sometimes resulting in natural mummification.The rate of skeletonization and the present condition of a corpse or carcass can be used to determine the time of death.After skeletonization, if scavenging animals do not destroy or remove the bones, acids in many fertile soils take about 20 years to completely dissolve the skeleton of mid- to large-size mammals, such as humans, leaving no trace of the organism. In neutral-pH soil or sand, the skeleton can persist for hundreds of years before it finally disintegrates. Alternately, especially in very fine, dry, salty, anoxic, or mildly alkaline soils, bones may undergo fossilization, converting into minerals that may persist indefinitely.

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