population growth rate Dotaz Zobrazit nápovědu
BACKGROUND: Xrn1 exoribonuclease is the major mRNA degradation enzyme in Saccharomyces cerevisiae. In exponentially growing cells, Xrn1 is localised in the yeast cells and directs the degradation of mRNA molecules. Xrn1 is gradually deposited and presumably inactivated in the processing bodies (P-bodies) as the yeast population ages. Xrn1 can also localise to the membrane compartment of the arginine permease Can1/eisosome compartment at the yeast plasma membrane. This localisation correlates with the metabolic (diauxic) shift from glucose fermentation to respiration, although the relevance of this Xrn1 localisation remains unknown. METHODS: We monitored the growth rates and morphology of Xrn1-green fluorescent protein (GFP) cells compared to wild-type and Δxrn1 cells and observed the Xrn1-GFP localisation pattern in different media types for up to 72 hours using fluorescence microscopy. RESULTS: We present the dynamic changes in the localisation of Xrn1 as a versatile tool for monitoring the growth of yeast populations at the single-cell level using fluorescence microscopy. CONCLUSIONS: The dynamic changes in the localisation of Xrn1 can be a versatile tool for monitoring the growth of yeast populations at the single-cell level. Simultaneously, Xrn1 localisation outside of P-bodies in post-diauxic cells supports its storage and cytoprotective function, yet the role of P-bodies in cell metabolism has still not yet been entirely elucidated.
- MeSH
- indukovaný potrat MeSH
- mortalita MeSH
- populační růst trendy MeSH
- socialismus MeSH
- Geografické názvy
- historické zeměpisné názvy MeSH
The pest potential of stored product mites depends on the reproduction rate that is affected by the environmental conditions. In this study we investigated the effect of temperature, ranging from 5 to 35 degrees C, on the population growth of three important mite species, Acarus siro, Tyrophagus putrescentiae and Auleroglyphus ovatus at 85% r.h. Starting with 10 individuals the population increase of mites was observed after 3 weeks of cultivation, or after 6 weeks for those kept at low temperatures (5, 10, 12.5, and 15 degrees C). The rate of increase was calculated for each temperature and species. The obtained data were fitted with polynomial models. The mite population growth rates increased with increasing moderate temperatures until 25 degrees C, when r ( m )-values were 0.179, 0.177 and 0.190 for A. siro, A. ovatus and T. putrescentiae, respectively. The lower development threshold was 10.2 degrees C in all three species. Estimated upper temperature threshold was higher in T. putrescentiae (49 degrees C) than in A. siro and A. ovatus (38 degrees C). Simulation of the rate of population increase under ideal conditions, using real temperature records obtained from Czech grain stores, showed that the pest mite populations increase only during 3.5 months within a typical 9-month storage season in Central Europe. These results indicate that control of mites, be it chemical, physical or biological, is recommended during the months when allergens and pests are produced, i.e. from September to mid November and in May.
- MeSH
- Acaridae růst a vývoj fyziologie MeSH
- jedlá semena parazitologie MeSH
- populační růst MeSH
- potravinářská parazitologie MeSH
- roční období MeSH
- teplota * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
BACKGROUND: Despite the increasing number of studies attempting to model population growth in various organisms, we still know relatively little about the population dynamics of long-lived species that reproduce only in the later stages of their life cycle, such as trees. Predictions of the dynamics of these species are, however, urgently needed for planning management actions when species are either endangered or invasive. In long-lived species, a single management intervention may have consequences for several decades, and detailed knowledge of long-term performance can therefore elucidate possible outcomes during the management planning phase. METHODOLOGY AND PRINCIPAL FINDINGS: We studied the population dynamics of an invasive tree species, Pinus strobus, in three habitat types represented by their position along the elevation gradient occupied by the species. In agreement with previous studies on the population dynamics of long-lived perennials, our results show that the survival of the largest trees exhibits the highest elasticity in all of the studied habitats. In contrast, life table response experiments (LTRE) analysis showed that different stages contribute the most to population growth rates in different habitats, with generative reproduction being more important in lower slopes and valley bottoms and survival being more important on rock tops and upper slopes. CONCLUSIONS: The results indicate that P. strobus exhibits different growth strategies in different habitats that result in similar population growth rates. We propose that this plasticity in growth strategies is a key factor in the invasion success of the white pine. In all of the investigated habitats, the population growth rates are above 1, indicating that the population of the species is still increasing and has the ability to spread and occupy a wide range of habitats.
- MeSH
- borovice růst a vývoj MeSH
- ekosystém * MeSH
- populační dynamika MeSH
- populační růst * MeSH
- zavlečené druhy * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Švýcarsko MeSH
- MeSH
- demografie MeSH
- lidé MeSH
- mortalita MeSH
- populační růst MeSH
- Check Tag
- lidé MeSH
Cílem studie je přiblížit vývoj demografické reprodukce obyvatelstva v České republice v uplynulém čtvrtstoletí. Pozornost je věnována především procesu demografického stárnutí, který je determinován vývojem dvou hlavních složek reprodukce obyvatelstva – porodnosti a úmrtnosti. Tyto základní demografické procesy prošly ve sledovaném období nemalými změnami, a to v důsledku společenských i ekonomických faktorů. Především jde o významný pokles plodnosti, ačkoliv se do rodivého věku dostaly početně silné populační ročníky ze 70. let minulého století, a snižování intenzity úmrtnosti, které má za následek neustálý nárůst naděje dožití. Vliv na počet, strukturu i rozmístění obyvatelstva má také migrace, která především ke konci sledovaného období měla výrazný vliv na meziroční změny početního stavu obyvatelstva. S procesem demografického stárnutí také souvisí otázka, v jakém zdravotním stavu se obyvatelstvo vyššího věku dožívá. Zdravotní stav se dá obecně hodnotit jak podle objektivních, tak subjektivních ukazatelů. Objektivní ukazatele často ale narážejí na ne příliš kvalitní datovou základnu, jelikož se jedná pouze o lékařem objektivně dokumentované skutečnosti, přičemž je zřejmé, že ne se všemi nemocemi lidé navštěvují své lékaře. Proto se čím dál tím více pozornosti zaměřuje na subjektivní ukazatele, kdy pomocí výběrových šetření obyvatelstvo přímo hodnotí svůj zdravotní stav. Z provedených průzkumů je patrné, že subjektivní hodnocení zdraví se za posledních dvacet let zlepšilo, přičemž je ale patrný trend zvyšování chronické nemocnosti obyvatelstva, a to nejen s věkem, ale i časem. Tato skutečnost může mít v souvislosti s procesem dalšího prohlubování demografického stárnutí výrazný vliv na fungování zdravotnického a sociálního systému v České republice.
The aim of the article is to describe the demographic development of the population in the Czech Republic in the last quarter-century. Particular attention is paid to the process of demographic ageing, which is determined by the development of two main components of population reproduction – fertility and mortality. These basic demographic processes had undergone considerable changes in the monitored period as a result of social and economic factors. In particular, there is a significant decrease in fertility, although the baby boomers generation from the 70s of the last century got into the reproductive age, and reduction of mortality, which has resulted in a constant increase of life expectancy. The number, structure and distribution of the population are also affected by migration; especially at the end of the monitored period migration had a significant effect on the annual change of numbers in the population. The process of demographic ageing is also related to the matter of health condition of the population which is growing old. State of health can be generally evaluated according to both objective and subjective indicators. Objective indicators do not have a good data base, since it is only a fact objectively documented by a doctor, and it is evident that people do not go the doctor with all their diseases. Therefore, more and more attention is paid to subjective indicators when surveyors directly assess their health status. According to the performed surveys, it is evident that the subjective evaluation of health over the last twenty years has improved, but there is also the trend of increasing chronic illness rate in the population, not only with age, but also in time. This fact may have a significant impact on the functioning of the medical and social system in the Czech Republic in connection with the process of demographic aging and its further deepening.
- MeSH
- emigrace a imigrace trendy MeSH
- lidé MeSH
- morbidita * trendy MeSH
- mortalita trendy MeSH
- populační dynamika * statistika a číselné údaje trendy MeSH
- populační růst * MeSH
- porodnost * trendy MeSH
- ukazatele zdravotního stavu * MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
