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001-es BibID:	BIBFORM078530
035-os BibID:	(WoS)000449861000003 (Scopus)85052627265
Első szerző:	Sebestyén Flóra (biológus)
Cím:	Reproductive mode, stem cells and regeneration in a freshwater cnidarian with postreproductive senescence / Flóra Sebestyén, Zoltán Barta, Jácint Tökölyi
Dátum:	2018
ISSN:	0269-8463 1365-2435
Megjegyzések:	In many basal metazoans, both somatic and reproductive functions are performed by cellular derivatives of a single multipotent stem cell population. Reproduction can drain these stem cell pools, imposing a physiological cost with subsequent negative effects on somatic maintenance functions. In the freshwater cnidarian Hydra oligactis, both asexual (budding) and sexual reproductive modes (production of resting eggs) are present, and both of these are dependent on a common pool of interstitial stem cells. Resting eggs tolerate harsh abiotic conditions which neither the parental animals, nor asexual offspring can survive (e.g., freezing). Therefore, when facing unfavourable conditions and increased mortality risk, hydra polyps are expected to show higher level of differentiation of interstitial stem cells into germ cells (i.e., sexual reproduction) than other cell types needed for self?maintenance or asexual reproduction. Here, by comparing sexually and asexually reproducing individuals to nonreproductives, we studied the physiological costs of reproduction (size of interstitial stem cell pools, their somatic derivatives and regeneration rate, which is dependent on these cell types) in H. oligactis polyps from a free?living Hungarian population prior to the onset of winter. Sexual individuals were characterized by significantly smaller interstitial stem cell pools, fewer nematoblasts involved in food capture and lower regeneration ability compared to nonreproductives, but asexuals did not differ from nonreproductive animals. We also found a negative correlation between germ cell counts and stem cell numbers in males (but not in females). We suggest that the lower numbers of these cell types and lower regenerative ability in sexual individuals reflect a somatic cost of sexual reproduction. Our results also suggest that increased differentiation of stem cells into gametes might limit investment into somatic functions in hydra polyps. Exhaustion of cellular resources (stem cells) could be a major mechanism behind the extreme postreproductive senescence observed in this species.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk cost of reproduction Evo-Devo Hydra interstitial cells life-history trade-offs semelparity
Megjelenés:	Functional Ecology. - 32 : 11 (2018), p. 2497-2508. -
További szerzők:	Barta Zoltán (1967-) (biológus, zoológus) Tökölyi Jácint (1984-) (biológus)
Pályázati támogatás:	EFOP-3.6.1 EFOP NKFIH FK 124164 egyéb NKFIH K 112527 egyéb ÚNKP-17- 4 egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM115498
035-os BibID:	(WoS)001085950500001 (Scopus)85174506888
Első szerző:	Tökölyi Jácint (biológus)
Cím:	Temperature-dependent scaling of fitness traits with body size in hydra / Tökölyi, Jácint
Dátum:	2024
ISSN:	0269-8463 1365-2435
Megjegyzések:	Body size strongly depends on developmental temperature. In more than 80% of the ectotherm species investigated, including bacteria, protists, invertebrates and vertebrates, individuals developing at lower temperatures exhibit protracted growth and achieve larger sizes than individuals developing at higher temperatures (referred to as the 'temperature-size rule', TSR). One hypothesis to explain the TSR posits that reproduction and/or survival change more steeply with size in cold environments, resulting in larger optimal body sizes and consequently increased selection for growth. However, clearly ascertaining whether size directly affects fitness traits in a temperature-dependent way is challenging due to the interdependence of size, reproduction and survival.To address this problem, experimental body size manipulation was performed in two male and two female strains of Hydra oligactis, a cold-adapted temperate freshwater invertebrate. Experimentally enlarged and reduced individuals were followed at two distinct temperatures (8 and 12degree celsius) in the laboratory to record sexual investment and postreproductive senescence. To gain insight into the underlying physiological processes, phenotypic observations were complemented with a large transcriptomic data set obtained from enlarged and reduced individuals from different temperatures. Within male hydra strains, fecundity increased, while survival decreased more steeply with size in cold, compared with warmer temperature. Females showed similar, though less emphasized, trends. Reduced animals in the cold had slower sexual development and were less able to undergo compensatory growth, suggesting temperature-dependent constraints on physiological performance.Reduced and enlarged males differed dramatically in the expression of reproductive genes at low, but not at higher temperature, while in females, a complex transcriptomic restructuring was seen. In particular, metabolic genes were strongly affected by size manipulation, suggesting resource acquisition and allocation as a central mechanism driving allometric patterns.These results suggest that being large is more beneficial in cold environments, at least in terms of reproduction, while at higher temperature even small individuals can maintain reproductive output. Lower reproduction, however, can be compensated by improved survival in small individuals facing colder environments. The reproductive advantage of large size can provide selection for increased growth at low temperature, thereby explaining the TSR in hydra.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Functional Ecology. - 38 : 1 (2024), p. 245-258. -
Pályázati támogatás:	MTA-DE Lendület LP12/2021 MTA Élettudományok - Biológiai tudományok
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: