Článek o vývoji vztahu akvaristiky a vědeckého výzkumu je zaměřen především na aspekty taxonomie, etologie a rozmnožování. Stručně jsou zmíněny počátky akvaristiky stojící na základech tehdejší vědy, a uvedena jména významných osobností, které ovlivnily vývoj chovu ozdobných ryb. Je zdůrazněn termín akvariologie, zavedený pro multidisciplinární vědecké základy akvaristiky., This article deals with the mutual relations between the aquarium hobby and scientific research, especially with respect to taxonomy, ethology and breeding. The beginnings of aquaristics, based on earlier scientific sources, are mentioned, and leading figures pioneering the developments in keeping tropical fish are also introduced. The term aquariology, applied to the multidisciplinary scientific basis of ornamental fish farming, is highlighted., Jindřich Novák., and Obsahuje seznam literatury
In juvenile trees growing at the rainforest understory, light is the most limiting factor for growth. It has been assumed that stomata quickly respond to light irrespective of the physical conditions prevailing before leaf illumination. Nevertheless, so far this issue has not been addressed for saplings of Amazonian tree species. The aim of this study was to determine how stomatal conductance (gs) and photosynthetic parameters of Amazonian saplings respond to diurnal variation in the physical environment and to rainfall seasonality. Light-saturated net photosynthetic rate (PNmax) and gs at light saturation (gsmax) were measured in the dry (August) and rainy (January) season of 2008 in saplings of 10 Amazonian tree species (Minquartia guianensis, Myrcia paivae, Protium apiculatum, Guatteria olivacea, Unonopsis duckei, Rinorea guianensis, Dicypellium manausense, Eschweilera bracteosa, Gustavia elliptica, and Tapura amazonica). At the forest understory, variables of the physical environment were measured. Rainfall seasonality did not affect PNmax and gsmax, nor was the effect of species on PNmax and gsmax significant (p>0.05). The gs and PNmax increased as the forest understory became brighter and warmer; as a result, PNmax and gsmax were higher at midday than early in the morning or in the afternoon. However, contrary to expectations, neither changes in air vapor pressure deficit nor air CO2 concentration at the forest understory affected stomatal opening. More investigation is needed to elucidate the role of environmental factors in modulating stomatal movements in juvenile trees growing beneath the dense canopy of tropical rainforests., R. A. Marenco, H. C. S. Nascimento, N. S. Magalhães., and Obsahuje bibliografii
Spiders are generalist predators that contribute to the control of pests in agroecosystems. Land use management determines habitats including refuges for hibernation and aestivation. The availability of shelters on the ground can be crucial for maintaining populations of spider within crops. We studied the effect of the number of stones on the surface of the soil on the spider community in selected olive groves in Trás-os-Montes (northeastern Portugal). The number of stones significantly influenced the overall diversity of spiders, abundance of immature individuals and abundance of ground hunters. Agricultural management practices aimed at the conservation of soil microhabitats such as hedgerows, stonewalls and stones on the ground should be promoted in order to maintain or increase the number of shelters for potential natural enemies of pests., Jacinto Benhadi-Marín, José A. Pereira, José A. Barrientos, José P. Sousa, Sónia A.P. Santos., and Obsahuje bibliografii
Retroviry jsou RNA viry, které se replikují v hostitelské buňce. Využívají enzymu reverzní transkriptázy, která přepisuje jejich RNA do DNA. Tato DNA je pak enzymem integrázou začleňována do hostitelského genomu. Pokud dojde k integraci retroviru v germinální linii, může se tento retrovirus stát součástí lidského genomu. V lidském genomu tyto retrovirové elementy (Human Endogenous Retroviruses = HERVs) tvoří až 8 % DNA. Donedávna se vědci domnívali, že HERVy jsou neaktivní, tzn. neinfikují další buňky. Během evoluce byly mnohokrát mutovány a pozbyly schopnosti genové exprese. Převažoval také názor, že HERVy nejsou ani trankribovány - nejsou přepisovány do mRNA. Ze současných výzkumů však vyplývá, že HERVy jsou hojně přepisovány v mnoha různých tkáních lidského těla. Někdy mohou z této mRNA dokonce vznikat krátké peptidy, které pak mohou buňku ovlivňovat. Jak rozsáhlý je význam transkripce, je nyní předmětem dalších zkoumání., A retrovirus is an RNA virus using its own reverse transcriptase and integrase to produce DNA from its genome and incorporate it into the host’s genome. When a retrovirus is integrated in a germ line, it can become a part of the host genome. In human genome these elements occupy about 8 % of DNA and are called human endogenous retroviruses (HERVs). During evolution they mutated and lost their function to infect other cells. They were considered inactive (not expressed), however, transcription of HERVs in many different tissues in most human cells has recently been proved., and Mirka Famfulíková, Jan Pačes.