Lamin C2 (LMN C2) is a short product of the lamin a gene. It is a germ cell-specific lamin and has been extensively studied in male germ cells. In this study, we focussed on the expression and localization of LMN C2 in fully-grown germinal vesicle (GV) oocytes. We detected LMN C2 in the fully-grown germinal vesicle oocytes of various mammalian species with confirmation done by immunoblotting the wild type and Lmnc2 gene deleted testes. Expression of LMN C2 tagged with GFP showed localization of LMN C2 to the nuclear membrane of the oocyte. Moreover, the LMN C2 protein notably disappeared after nuclear envelope breakdown (NEBD) and the expression of LMN C2 was significantly reduced in the oocytes from aged females and ceased altogether during meiotic maturation. These results provide new insights regarding LMN C2 expression in the oocytes of various mammalian species.
- MeSH
- jaderný obal genetika MeSH
- laminin genetika MeSH
- meióza genetika MeSH
- messenger RNA genetika MeSH
- myši knockoutované MeSH
- myši MeSH
- oocyty růst a vývoj metabolismus MeSH
- oogeneze genetika MeSH
- ovarium růst a vývoj MeSH
- spermatocyty růst a vývoj MeSH
- testis růst a vývoj MeSH
- vývojová regulace genové exprese genetika MeSH
- zárodečné buňky růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Blastogregarines are poorly studied parasites of polychaetes superficially resembling gregarines, but lacking syzygy and gametocyst stages in the life cycle. Furthermore, their permanent multinuclearity and gametogenesis by means of budding considerably distinguish them from other parasitic Apicomplexa such as coccidians and hematozoans. The affiliation of blastogregarines has been uncertain: different authors considered them highly modified gregarines, an intermediate apicomplexan lineage between gregarines and coccidians, or an isolated group of eukaryotes altogether. Here, we report the ultrastructure of two blastogregarine species, Siedleckia nematoides and Chattonaria mesnili, and provide the first molecular data on their phylogeny based on SSU, 5.8S, and LSU rDNA sequences. Morphological analysis reveals that blastogregarines possess both gregarine and coccidian features. Several traits shared with archigregarines likely represent the ancestral states of the corresponding cell structures for parasitic apicomplexans: a distinctive tegument structure and myzocytotic feeding with a well-developed apical complex. Unlike gregarines but similar to coccidians however, the nuclei of male blastogregarine gametes are associated with two kinetosomes. Molecular phylogenetic analyses reveal that blastogregarines are an independent, early diverging lineage of apicomplexans. Overall, the morphological and molecular evidence congruently suggests that blastogregarines represent a separate class of Apicomplexa.
- MeSH
- aktivace lymfocytů MeSH
- Apicomplexa klasifikace genetika růst a vývoj ultrastruktura MeSH
- bazální tělíska metabolismus MeSH
- elektronová mikroskopie MeSH
- fylogeneze * MeSH
- protozoální DNA genetika MeSH
- zárodečné buňky růst a vývoj ultrastruktura MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
From an evolutionary perspective, ageing is a decrease in fitness with chronological age - expressed by an increase in mortality risk and/or decline in reproductive success and mediated by deterioration of functional performance. While this makes ageing intuitively paradoxical - detrimental to individual fitness - evolutionary theory offers answers as to why ageing has evolved. In this review, I first briefly examine the classic evolutionary theories of ageing and their empirical tests, and highlight recent findings that have advanced our understanding of the evolution of ageing (condition-dependent survival, positive pleiotropy). I then provide an overview of recent theoretical extensions and modifications that accommodate those new discoveries. I discuss the role of indeterminate (asymptotic) growth for lifetime increases in fecundity and ageing trajectories. I outline alternative views that challenge a universal existence of senescence - namely the lack of a germ-soma distinction and the ability of tissue replacement and retrogression to younger developmental stages in modular organisms. I argue that rejuvenation at the organismal level is plausible, but includes a return to a simple developmental stage. This may exempt a particular genotype from somatic defects but, correspondingly, removes any information acquired during development. A resolution of the question of whether a rejuvenated individual is the same entity is central to the recognition of whether current evolutionary theories of ageing, with their extensions and modifications, can explain the patterns of ageing across the Tree of Life.
- MeSH
- biologická adaptace genetika MeSH
- biologická evoluce * MeSH
- fertilita genetika MeSH
- genetická pleiotropie MeSH
- lidé MeSH
- mutace * MeSH
- omlazení fyziologie MeSH
- rozmnožování genetika MeSH
- stárnutí genetika MeSH
- zárodečné buňky růst a vývoj metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
In plants, gametogenesis occurs late in development, and somatic mutations can therefore be transmitted to the next generation. Longer periods of growth are believed to result in an increase in the number of cell divisions before gametogenesis, with a concomitant increase in mutations arising due to replication errors. However, there is little experimental evidence addressing how many cell divisions occur before gametogenesis. Here, we measured loss of telomeric DNA and accumulation of replication errors in Arabidopsis with short and long life spans to determine the number of replications in lineages leading to gametes. Surprisingly, the number of cell divisions within the gamete lineage is nearly independent of both life span and vegetative growth. One consequence of the relatively stable number of replications per generation is that older plants may not pass along more somatically acquired mutations to their offspring. We confirmed this hypothesis by genomic sequencing of progeny from young and old plants. This independence can be achieved by hierarchical arrangement of cell divisions in plant meristems where vegetative growth is primarily accomplished by expansion of cells in rapidly dividing meristematic zones, which are only rarely refreshed by occasional divisions of more quiescent cells. We support this model by 5-ethynyl-2'-deoxyuridine retention experiments in shoot and root apical meristems. These results suggest that stem-cell organization has independently evolved in plants and animals to minimize mutations by limiting DNA replication.
- MeSH
- akumulace mutací MeSH
- Arabidopsis genetika růst a vývoj MeSH
- diploidie MeSH
- genom rostlinný genetika MeSH
- kořeny rostlin genetika růst a vývoj MeSH
- meristém genetika růst a vývoj MeSH
- mutace genetika MeSH
- regulace genové exprese u rostlin MeSH
- replikace DNA genetika MeSH
- rostlinné buňky MeSH
- sekvenční analýza DNA MeSH
- stonky rostlin genetika růst a vývoj MeSH
- výhonky rostlin genetika růst a vývoj MeSH
- zárodečné buňky růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Kryptorchizmus je najčastejšia vrodená chyba mužských pohlavných orgánov znamenajúca neprítomnosť semenníkov v skróte. Pri narodení má približne 5 % donosených novorodencov nezostúpený semenník, vo veku 12 mesiacov je to už len 1 %. Keďže v 6. mesiaci dochádza k znižovaniu počtu zárodočných buniek a spontánny zostup po tomto období je vzácny, liečba kryptorchizmu už môže začať v tomto období a mala by byť ukončená do veku 18 mesiacov. Pri hmatnom semenníku je indikovaná operačná liečba – orchidopexia z inguinálneho prístupu, pri nehmatnom semenníku je indikovaná diagnostická laparoskopia – pri náleze nízko uloženého intraabdominálneho semenníka je možná jednodobá orchidopexia bez prerušenia testikulárnych ciev, pri vysoko uloženom intraabdominálnom semenníku sa pokračuje jednodobou alebo dvojdobou orchidopexiou s prerušením testikulárnych ciev. V súčasnosti získava v liečbe kryptorchizmu význam adjuvantná hormonálna liečba k operačnej liečbe, ktorá môže zlepšiť fertilitu. Hormonálna liečba je však stále kontroverzná a aj napriek pozitívnemu vplyvu na fertilitu má mnoho odporcov a zatiaľ nie je štandardnou liečbou kryptorchizmu.
Cryptorchidism is the most common congenital anomaly of the male genitalia meaning the absence of testicles in the scrotum. Approximately 5% of full-term newborn males have undescended testicle, at the age of 12 months it is only 1%. As in the 6th month there starts a decrease of germ cell count and the spontaneous descent after this age is rare, the therapy of cryptorchidism should start already at this age and should be completed until the age of 18 months. If the testicle is palpable the orchidopexy from the inguinal approach is indicated. If the testicle is unpalpable the diagnostic laparoscopy is indicated. If a low intra-abdominal testicle is found, one-stage orchidopexy without transection of testicular vessels is possible, if a high intra-abdominal testicle is found one or two stage orchidopexy with the transection of testicular vessels is performed. At the present time the postoperative hormonal treatment becomes significant in the treatment of the cryptorchidism and may have a beneficial effect on fertility. The hormonal treatment is still controversial and has many opponents despite the positive influence on the fertility, yet it is still not a standard treatment for cryptorchidism.
- MeSH
- choriogonadotropin škodlivé účinky terapeutické užití MeSH
- fyzikální vyšetření metody MeSH
- hormon uvolňující gonadotropiny škodlivé účinky terapeutické užití MeSH
- kojenec MeSH
- kombinovaná terapie MeSH
- kryptorchismus * diagnóza epidemiologie etiologie terapie MeSH
- laparoskopie metody MeSH
- látky působící na reprodukci škodlivé účinky terapeutické užití MeSH
- lidé MeSH
- mužská infertilita prevence a kontrola MeSH
- orchidopexe metody MeSH
- předškolní dítě MeSH
- testikulární nádory prevence a kontrola MeSH
- testis embryologie chirurgie růst a vývoj účinky léků MeSH
- urologické chirurgické výkony u mužů metody MeSH
- zárodečné buňky růst a vývoj MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- MeSH
- genetická terapie MeSH
- prionové nemoci etiologie MeSH
- zárodečné buňky růst a vývoj MeSH
- Publikační typ
- kongresy MeSH
- MeSH
- dieta MeSH
- krysa rodu rattus MeSH
- mitóza účinky léků MeSH
- Sertoliho buňky růst a vývoj sekrece MeSH
- techniky in vitro MeSH
- vitamin A MeSH
- zárodečné buňky růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
