The aim of this study was to analyze the effects of chronic administration of the β-adrenoceptor agonist clenbuterol (2 mg/kg body weight/day for a period of 30 days) on the major contractile protein (myosin) in the left ventricular muscle of the adult mouse heart. Separation of myosin heavy chain (MHC) isoforms on 7.5 % glycerol SDS-PAGE and subsequent quantification of the gels by laser densitometry showed a 6.5-fold increase in the β-isoform of MHC in the clenbuterol-treated group. The α: β ratio of these two isoforms in the control group was 98.16±0.14 %: 1.83±0.14 %, whereas in the treated group it was 88.05±1.15 %: 11.95±1.15 %. Actomyosin ATPase activity assay demonstrated a significant (20 %) decline in ATPase activity of the tissue in the β-agonist-treated group. These results suggest that chronic clenbuterol treatment is capable to induced the transformation of MHC isoforms increasing the slow β-MHC isoform, which may contribute to the altered contractile mechanics of clenbuterol-treated hearts., S. N. Patiyal, S. Sharma., and Obsahuje bibliografii a bibliografické odkazy
Článek přestavuje taxonomicky problematický rod chrpa z čeledi Asteraceae. Jsou diskutovány současné pohledy na vymezení a vnitřní členění rodu založené na molekulárních znacích. Dále je popsána problematika hybridizace, která je v rodu velmi častá, a její souvislost s polyploidií (druhy stejné ploidie se často kříží za vzniku rozsáhlých a variabilních hybridních rojů, zatímco mezi ploidiemi je silná reprodukční bariéra)., Centaurea is a taxonomically critical genus from the Asteraceae family. Current delimitation of the genus and its internal classification based on molecular data are discussed. Hybridization and polyploidy are common in Centaurea. The frequency of hybridization depends on ploidy levels of the taxa (homoploid taxa usually hybridize easily and form extensive and variable hybrid swarms, while heteroploid taxa are reproductively strongly isolated)., and Petr Koutecký.
Pollution of the water environment by foreign substances is an important factor affecting the health of fish, their reproduction and hygienic quality. Almost 100,000 chemical compounds are currently used, and get into the environment. This article describes the causes and sources of water pollution and deals with the known effects of particular contaminants, including mercury, on freshwater fish, i. a. in terms of their position in the food chain. and Tomáš Randák.
Recently a large number of studies have reported an increase in the variability in the climate, which affects behavioural and physiological adaptations in a broad range of organisms. Specifically, insects may be especially sensitive to climatic fluctuations, as their physiology and life history traits, like those of other ectotherms, are predominantly affected by environmental factors. Here we aimed to investigate climate-induced changes in several morphometric measures of the Heath Fritillary in North-Eastern Hungary, which is a highly diverse transitional area. During this study we tested the following hypotheses: (i) climate affects genitalia and body size to various degrees (ii) increasing variability in climate induces higher levels of fluctuating asymmetry and variance in all morphological characters. To our knowledge, this study is the first to analyse simultaneously wing size and structure of genitalia of a butterfly in response to variability in climate. Our findings suggest that wing and genital traits may exhibit similar degrees of stability in response to a more variable climate, although the response in terms of forewing size differs from that of other body measurements and the structure of the genitalia. These findings suggest that global climate change may affect lepidopteran body metrics over longer periods of time. Our findings parallel the results of investigations showing that insect morphology might be modified by environmental changes, which is especially the case for those body parts that are phenotypically very variable. However, we found no evidence that increasing variability in climate would induce higher levels of fluctuating asymmetry and greater variability in morphological characters., Edit Juhász, Zsolt Végvári, János P. Tóth, Katalin Pecsenye, Zoltán Varga., and Obsahuje bibliografii
The article primarily describes the original results of Czech research into interactions between ants and plants in Central Europe. The role of myrmecophily is illustrated by long-term case studies (mountain pastures, industrial deposits) at the ecosystem level. Facilitation and acceleration of spontaneous vegetation succession by the ants’ activity with their nest construction and seed dispersal can be used as a tool in assisted ecological restoration. and Pavel Kovář.
Two families of carnivorous plants have been described by Czech botanists: Byblidaceae Domin 1922 and Drosophyllaceae Chrtek, Slavíková and Studnička 1989. A history of the descriptions and some basic and interesting information about these families are presented. and Adam Veleba.
Za posledních několik let byla publikována řada významných archeogenetických studií týkajících se datování a geografické lokalizace posledního společného předka lidského chromozomu Y. Je to dáno dramatickým rozvojem molekulárně biologických technik, díky nimž je dnes možné přečíst daleko větší objem dat, než tomu bylo dříve. Dozvěděli jsme se, že „Y chromozomový Adam“ bude asi nakonec starší než „mitochondriální Eva“ a že jeho synové prodělali mnohem bouřlivější demografický vývoj než dcery Eviny., Several important archaeogenetic studies dealing with age estimates and the geographical locations of the last common ancestor of our Y chromosome have been published over the past few years. This is due to the dramatic development of molecular biological techniques, which made it possible to read a much larger amount of data than was possible before. We learned that the "Y chromosome Adam" might be even older than "mitochondrial Eve" and that his sons went through a much more complex demographic history than Eve’s daughters., and Viktor Černý.
Kofein podaný večer snižuje ospalost a zvyšuje pozornost a schopnost poznávat. Zpožďuje však též časový cirkadiánní systém, neboť následující den po podání je zpožděn rytmus v tvorbě melatoninu, ukazatele fáze cirkadiánních hodin. Vynucená desynchronizace mezi spánkem a dobou vysoké noční hladiny melatoninu, která signalizuje subjektivní noc jedince, vede k narušení celého cirkadiánního systému., Evening caffeine consumption attenuates sleepiness and increases attention and cognitive abilities. In addition, it delays the circadian timekeeping system, as the next day after caffeine consumption the human melatonin rhythm, a circadian clock phase marker, is delayed. Forced desynchrony of sleep and the interval of high melatonin levels, which indicates a subjective night for an individual, leads to a disruption of the circadian system., and Helena Illnerová.
Metody sekvenování nové generace (NGS) poprvé vnesly hlubší pohled do diverzity lidského střevního mikrobiálního ekosystému, jehož velikost je nečekaně veliká. Poměr lidských a mikrobiálních buněk se pohybuje v rozmezí od 1:1 až po 1:100 a lze říci, že jak lidé, tak i další savci žijí ve složitých konsorciích složených z virů, archaeí a bakterií tvořící mikrobiom spolu s mikroskopickými houbami a jednobuněčnými a mnohobuněčnými eukaryoty, tj. prvoky a helminty. Největší pozornost je prozatím věnována bakteriálnímu mikrobiomu představujícímu možná nejvíce různorodý segment ekosystému lidského těla., The Next Generation Sequencing (NGS) methods has brought a deeper insight into the diversity of a human intestinal microbial ecosystem. The ratio of human and microbial cells ranges from 1:1 to 1:100. One might say that humans (and other mammals) live in a complex consortium of viruses, bacteria, archaea - forming what is known as a microbiome - together with microscopic fungi, unicellular and metazoan eukaryotes (protists and helminths). Most attention has so far been paid to the bacterial microbiome that signifies perhaps the most diverse segment of the ecosystem of human body., and Jan Votýpka, Kateřina Jirků Pomajbíková.
Genomy eukaryotických organismů se nesmírně liší svou velikostí, kdy dosahují až 66tisícinásobného rozdílu. Největší v současnosti známý genom byl nalezen u vraního oka japonského (Paris japonica), nápadné byliny z Japonska. Množství jaderné DNA u tohoto druhu bylo odhadnuto na 153,32 pg, jeho genetický kód je tak 50krát delší než ten lidský., Genomes of eukaryotic organisms vary tremendously in size, spanning an approximately 66,000-fold range. Recently the largest genome has been discovered in Paris japonica, a striking plant native to Japan. The amount of nuclear DNA was estimated at 153.32 pg, making the genetic code 50 times longer than that of a human being., and Jan Suda.