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Mechanisms and peculiarities of dormancy in veretebrates and invertebrates Биологический покой у позвоночных и беспозвон

Mechanisms and peculiarities of dormancy in veretebrates and invertebrates Биологический покой у позвоночных и беспозвоночных . N. Abramson, V . Alekseev Zoological Institute RAS. Terms and definitions. Laudien 1973. Keilin (1959). Active life=normal metabolism.

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Mechanisms and peculiarities of dormancy in veretebrates and invertebrates Биологический покой у позвоночных и беспозвон

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  1. Mechanisms and peculiarities of dormancy in veretebrates and invertebratesБиологический покой у позвоночных и беспозвоночных N. Abramson, V. Alekseev Zoological Institute RAS

  2. Terms and definitions Laudien 1973 • Keilin (1959) Active life=normal metabolism Induced directly by unfavorable conditions and development is resumed soon after return to favorable conditions includes a complicate internal hormonal mechanism that needs in time both for beginning and finishing its work. As result diapause starts before really harsh conditions and can not be immediately broke even if favorable conditions return

  3. The first researches on the diapause were carried out at the beginning of the 20th century on the silkworm (Bombix mori). The neologism “diapause” was subsequently extended from insects to other taxa which exhibited a similar kind of adaptation in many details, including hormone identity or level of metabolic depression; theseincluded porifera, turbellaria, briozoa, rotifera, oligochaeta, tardigrada, crustacea and collembola.

  4. Определение диапаузы • Диапаузой называется фаза покоя в жизненном цикле организма, определяемая активностью гормонов и по длительности сравнимая с продолжительностью неблагоприятного для жизнедеятельности сезона. Таким образом диапауза – термин прежде всего экологический, компонент популяционной динамики. Родственные, но не аналогичные понятия спячка (регулируется только внешними факторами), сон (длительность близкая к длине суток), анабиоз (ангидробиоз, криобиоз), эстивация, гибернация и др. относятся к разряду терминов физиологических.

  5. Александр Сергеевич Данилевский (1911-1969) • А.С. Данилевский был прямым потомком А.С. Пушкина и одновременно родственником Н.В. Гоголя

  6. The diapause may occur at different development stages

  7. Продолжительность диапаузы и угнетение метаболизма

  8. Сходные характеристики биологического покоя у позвоночных и беспозвоночных • Способность к диапаузе проявляют филогенетически очень далекие различные отряды под воздействием экологических условий • Стадии покоя присутствуют на всех этапах индивидуального развития • уровень угнетения (у диапузирующих особей в 3-6 раз ниже если не считать анабиоз чем у активных при той же температуре) и характерные фазы протекания (наличие периодов подготовки, градуальное угасание функций, рефрактерная фаза, выход ) весьма сходны в расмотренных примерах диапаузы у обеих групп животных. • Продолжительность рефрактерной фазы диапаузы почти у всех как позвоночных, так и беспозвоночных организмов обычно не превышает 3 месяцев, после чего они могут уже быть реактивированы переводом в благоприятные условия. Этот период совпадает с периодом активности диапаузу-ингибирующего гормона как это было показано для декапод • Гормоны участвующие в механизмах запуска диапаузы очень сходны у всех организмов.

  9. Hibernation in mammals Hibernation is an adaptive strategy that is used by species in several mammalian orders to conserve energy in cold or inhospitable environments. During hibernation these mammals dramatically lower their metabolic, heart, and respiratory rates as well as their body temperature in a precisely controlled manner. In species with winter hibernation the body temperature usually falls below 10°С. Minimal temperature in 3°С was recorded in arctic ground squirrel Spermophilus undulates, thoughin majority of this species do not fall below 5°С.

  10. Remarkably hibernation occurs in seven different orders of mammals insectivores primates bats monotremes rodents marsupials

  11. primates bats insectivores ungulates carnivores rodents lagomorphs marsupials monotremes two hypothesis explaining the interspersed nature of the distribution of extant hibernating species through Mammalia common ancestor is a hibernator common ancestor is not a hibernator Lineages where the ability to hibernate partially lost or completely lost Lineages where hibernation must have arisen

  12. Expression of PDK-4 during the hibernation season. (A) Northern blot of total RNA from thehearts of active and hibernating 13-linedground squirrels. (B) Bar graph summarizing PDK-4 mRNA levels in the hearts of sibling and nonsibling ground squirrels (C) Tissue distribution of PDK-4 mRNA from a single hibernating animal sacrificed in January during hypothermic torpor (Tb 5 5°C). Tissues are asindicated above each lane

  13. cDNAs encoding human and ground squirrel PTLs expressed inthe yeast P.pastorisboth human and ground squirrel PTLperform remarkably well at low temperatures. At 0◦C, theenzyme from ground squirrel still maintains 48 and 33%of the maximal activity (seen at 37◦C) with tributyrin andtriolein respectively. Human PTL showed 42% maximal activityat 0◦C using tributyrin and an amazing 55% maximalactivity using triolein.This resultshows that the low-temperature catalysis seen with a proteinin hibernators is also found in humans.

  14. Model depicting the central role of differential gene expression during hibernation. Single arrows indicate direct effects, whereas multiple arrows indicate an effect that requires multiple intermediate events

  15. similar or close in vertebrate and invertebrates • Displayed independently in different sometimes very distant orders under the influence of environmental factors • occur at different development stages (e.g. eggs, embryos, juveniles or adults) • Suppression of metabolism (in diapause is 3-6 times lower than in in active at the same ambient temperature) and characteristic features of development (period of preparing, gradual suppression of metabolic functions, refractory phase, ,exit) • The duration of refractory phase usually do not exceed 3 months, after that they could be reactivated by transfer to favorable conditions. This period coincides with the period of activity of diapause inhibiting hormone as it was shown for decapodes (Alexseev, 1998). • There is significant similarity in chemical mechanism of hormonal control of resting phase in these animals гормоны,

  16. Заключение • Диапауза одна из древнейших и глубоких адаптаций живого для перенесения неблагоприятных условий • Длительность диапаузы достигает по меньшей мере десятков тысяч лет • Эта адаптация в той или иной форме присуща всем известным типам организмов и по-видимому генетически сходна на всем протяжении

  17. Спасибо за внимание

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