487 research outputs found
Role of the Mitochondrial Genome During Early Development in Mice
The role of the mitochondrial genome in early development and differentiation was studied in mouse embryos cultured in vitro from the two to four cell stage to the blastocyst (about 100 cells). During this period the mitochondria undergo morphological differentiation: progressive enlargement followed by an increase in matrix density, in number of cristae, and in number of mitochondrial ribosomes. Mitochondrial ribosomal and transfer RNA synthesis occurs from the 8 to 16 cell stage on and contributes to the establishment of a mitochondrial protein-synthesizing system. Inhibition of mitochondrial RNA- and protein-synthesis by 0.1 µg/ml of ethidium bromide or 31.2 µg/ml of chloramphenicol permits essentially normal embryo development and cellular differentiation. Mitochondrial morphogenesis is also nearly normal except for the appearance of dilated and vesicular cristae in blastocyst mitochondria. Such blastocysts are capable of normal postimplantation development when transplanted into the uteri of foster mothers. Higher concentrations of these inhibitors have general toxic effects and arrest embryo development. It is concluded that mitochondrial differentiation in the early mouse embryo occurs through the progressive transformation of the preexisting mitochondria and is largely controlled by the nucleocytoplasmic system. Mitochondrial protein synthesis is required for the normal structural organization of the cristae in blastocyst mitochondria. Embryo development and cellular differentiation up to the blastocyst stage are not dependent on mitochondrial genetic activity
Swiss Legal Status on the Protection of Whistleblowers: Taking into account the EU Directive on the protection of persons who report breaches of Union law
The EU Whistleblower Protection Directive came into force on 16 December 2019. Switzerland
continues to struggle with this topic: the Swiss National Council (Nationalrat) dismissed
a draft law on its introduction on 3 June 2019 and, after the Swiss Council of States
(Ständerat) approved the draft law without changes on 16 December 2019, dismissed it
again on 5 March 2020
A pozitĂv pszicholĂłgia missziĂłja a modern társadalomban = Mission of positive psychology in modern society. Paradigm Shift in Social Science?
A modern kultĂşra jelentĹ‘sen átformálta a társadalmi valĂłságot, valamint az emberek Ă©letmĂłdját, az egĂ©szsĂ©ghez Ă©s betegsĂ©ghez valĂł viszonyulását. A tudományos haladás korában sokáig a problĂ©mák feltárása, a patolĂłgiás állapotok kiszűrĂ©se volt a közĂ©ppontban, ami mĂ©g jelentĹ‘sebbĂ© vált a 20. században a háborĂşs Ă©s egyĂ©b traumák hatására. A pozitĂv pszicholĂłgia fejlĹ‘dĂ©se döntĹ‘en a második világháborĂş után kezdĹ‘dött, de fĹ‘kĂ©nt a 1970-es Ă©vekben erĹ‘södött meg. CĂ©lja azoknak a tĂ©nyezĹ‘knek a felkutatása Ă©s erĹ‘sĂtĂ©se, amelyek az egyĂ©nek Ă©s közössĂ©gek jĂłllĂ©tĂ©t segĂtik elĹ‘. A vĂ©dĹ‘faktorok jelentĹ‘sĂ©ge kĂĽlönösen a posztmodern korban nĹ‘tt meg, amelyet kockázati társadalomnak is nevezĂĽnk. A pozitĂv egĂ©szsĂ©gpszicholĂłgia kutatási eredmĂ©nyei hozzájárulhatnak a nĂ©pegĂ©szsĂ©gĂĽgyi programok hatĂ©kony megvalĂłsĂtásához. Ez a kelet-eurĂłpai tĂ©rsĂ©gben kĂĽlönösen fontos, ahol a társadalmi folyamatok kevĂ©sbĂ© járulnak hozzá, hogy az egyĂ©nek belsĹ‘ kontrollját elĹ‘segĂtĹ‘ stabil önbecsĂĽlĂ©s alakuljon ki
Serdülők értékorientációja és egészségmagatartása
A serdĂĽlĹ‘k Ă©rtĂ©korientáciĂłi, bár mĂ©g alakulĂłban vannak, szorosan összefĂĽggnek a társadalom uralkodĂł Ă©rtĂ©krendjĂ©vel. Az iskolások által preferált Ă©rtĂ©kek kihatnak a gyerekek iskolai Ă©letĂ©re, mindennapi viselkedĂ©sĂ©re, választásaira. Vizsgálatunkban arra koncentráltunk, hogy a serdĂĽlĹ‘k Ă©rtĂ©korientáciĂłi mikĂ©nt fĂĽggnek össze magatartásukkal Ă©s szociodemográfiai jellemzĹ‘ikkel. Az eredmĂ©nyek arra hĂvják fel a figyelmet, hogy jĂłl elkĂĽlönĂĽlnek a belsĹ‘, illetve kĂĽlsĹ‘ Ă©rtĂ©kekkel összefĂĽggĹ‘ változĂłk, illetve ennek nyomán az iskolások kĂ©t csoportja
Adolescent Life Satisfaction: Association with Psychological, School-Related, Religious and Socially Supportive Factors
Mitochondrial DNA replication in sea urchin oocytes
Mitochondrial DNA (mtDNA) replicative intermediates from Strongylocentrotus purpuratus oocytes were isolated by ethidium bromide-CsCl density gradient centrifugation and examined by electron microscopy after formamide spreading. In some experiments, the mtDNA was radioactively labeled by exposing isolated oocytes to [3H]thymidine. Oocyte mtDNA replication appears to follow the displacement loop model outlined in mouse L cells. There are differences in detail. The frequency of D-loop DNA is much lower in oocytes, suggesting that the relative holding time at the D-loop stage is shorter. Duplex synthesis on the displaced strand occurs early and with multiple initiations. The frequency of totally duplex replicative forms, or Cairns' forms, is the highest reported for mtDNA. The differences may be related to the fact that oocyte mtDNA replication occurs in the absence of cell division and need not be coordinated with a cell cycle. Molecules with expanded D loops banded in the intermediate region between the lower and upper bands in an ethidium bromide-CsCl gradient, supporting the notion that displacement replication proceeds on a closed circular template which is subject to nicking-closing cycles. In mature sea urchin eggs, replicative forms are absent and virtually all the mtDNA is stored as clean circular duplexes. Some novel structural variants of superhelical circular DNA (molecules with denaturation loops and double branch-migrated replicative forms) are reported
Cytoplasmic DNA in the unfertilized sea urchin egg: Physical properties of circular mitochondrial DNA and the occurrence of catenated forms
The mitochondrial DNA in the unfertilized egg of the sea urchin Lytechinus pictus is present in an amount approximately seven times that of the haploid nuclear DNA.(1) The mitochondrial DNA has a higher buoyant density than the nuclear DNA and consists of circular duplex molecules of a uniform size of about 5µ. The circular DNA has been recovered(1) in both the intact (closed) and nicked (open) states characteristic of the circular duplex viral DNA's(2) and the mitochondrial DNA's from birds and mammals.(3, 4
TeĂłria Ă©s Praxis: Fantom Ă©s fikciĂł Marie Darrieussecq regĂ©nyeiben Ă©s elmĂ©leti Ărásaiban
Multi-Level Protective Factors of Adolescent Smoking and Drinking
Adolescence is the most critical life stage for experimentation with substance use; however, this is also the most suitable period for strengthening protective factors and thus promoting adult physical and mental health. Since smoking and drinking still appear among the most frequent types of substance abuse in Europe, this study aims to examine the role of potential protective factors at multiple levels for adolescent smoking and drinking: psychological factors at the individual level, aspects of school attachment at the school level, social support variables at the social level, and measures of quality of life at the level of mental health. This cross-sectional survey involved a sample of adolescents (aged 11–18 years, N = 276) in Budapest and villages in its metropolitan area (Hungary). In addition to descriptive statistics, logistic regression analyses were used to detect odds for potential protective factors. There were no sex differences in adolescents’ substance use. Self-control seems to be a universal and most determining protective factor against substance use, while other potential protective factors (self-esteem, resilience, social support from family or significant others, school attachment, and mental well-being) may also contribute to prevention. However, age and friend support acted as risk factors. Findings suggest that a complex approach to prevention should receive consideration
Stressz, coping és reziliencia korai serdülőkorban
Tanulmányunkban a korai serdĂĽlĹ‘k Ă©szlelt stresszterheltsĂ©ge, az általuk alkalmazott coping stratĂ©giák Ă©s a rájuk jellemzĹ‘ reziliencia-mutatĂłk összefĂĽggĂ©seit elemezve azonosĂtottuk a mintában szereplĹ‘ tanulĂłk klasztereit. Három klasztert sikerĂĽlt elkĂĽlönĂteni a stressz-szinttĹ‘l fĂĽggĹ‘en: a magas stressz-szint egyĂ©rtelműen összefĂĽgg a reziliencia hiányával Ă©s a maladaptĂv coping mĂłdszerek alkalmazásával, az alacsony stressz-szint viszont Ă©rdekes mĂłdon nem az aktĂv problĂ©mafĂłkuszĂş mĂłdszerekkel hozhatĂł összefĂĽggĂ©sbe, hanem a maladaptĂv coping hiányával. VĂ©gĂĽl a közepes stressz-szint a problĂ©mamegoldĂł mĂłdszerek alkalmazásával tűnt ki, valamint a barátkozással, társas támogatás igĂ©nybevĂ©telĂ©vel. Ăšgy tűnik, hogy önmagában az olyan coping technikáktĂłl valĂł tartĂłzkodás, mint pĂ©ldául az önvád, az elfojtás vagy az aggĂłdás, erĹ‘sĂtheti a rezilienciát Ă©s a pszicholĂłgiai jĂłllĂ©tet
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