Female hybrids of the cross Chironomus t. thummi female × Ch. t. piger male which are largely affected by the sterility inducing Rud syndrome were backcrossed with males of both parental strains. The aim of the study was to provide information about those egg volumes that are insufficient for a normal embryogenesis and to ascertain whether in the hybrids the lethally small egg size represents a new abnormal trait of the Rud syndrome. The egg masses obtained contain eggs of very different sizes with volumes ranging from 0.5 nl to 3.49 nl. Embryo mortality is unusually frequent in those eggs of the backcrosses and of the parental strains that have volumes smaller than 1.5 nl. An egg volume of 1.5 nl represents in Ch. thummi the lower limit for those volumes that are sufficient for a normal embryogenesis. Mortality increases with decreasing egg size, reaching 100% in backcross eggs with volumes of 0.99 nl and smaller. Small egg size is a new trait of the Rud syndrome affected thummi female × piger male hybrids. This trait is part of a postzygotic reproductive isolation barrier between thummi and piger and manifests first in the backcrosses. Most backcross eggs show volumes between 1.5 nl and 2.99 nl. Within this volume range the amount of mortality does not depend upon egg volume. Here, embryo death is great in the backcrosses but normal in the parental strains. The high frequency of embryo death in the backcrosses must be predominantly due to the action of the Rud syndrome and a second hybrid syndrome, called HLE syndrome. Since further characteristic traits of these syndromes could be detected in surviving backcross individuals, the study demonstrates the occurrence of the syndromes in this generation also. Therefore, the postzygotic reproductive isolation mechanism of both hybrid syndromes is effective in the hybrids and in their progeny as well., Klaus Hägele, Monika Kasper-Sonnenberg, 4 obrázky, 2 tab., and Lit.
The half-popular compositions traditionally referred to as broadside ballads are a specific type of source. Some of them reflect Biblical, legendary and historical events in Egypt and the Near East. Although the factual importance of such ballads in not great, they have some informative value, because their texts mirror the attitudes and opinions of the lower social classes, in this case clearly influenced by the antithesis of Christianity and Islam, or also Judaism. They show that the authors of broadside ballads kept alive deep-rooted stereotypes, mainly the stereotype of Turks as pagans and tyrants. and Michal Klacek.
Energetická soběstačnost patří podle Světové obchodní organizace mezi desítku výzev, jimž budeme čelit v následujících desetiletích. Současné dominantní zdroje energie nejsou trvalým řešením, a tak musíme nejen hledat zdroje nové, ale přitom i zdokonalovat její přeměnu a vyřešit skladování. Právě to je jedním z úkolů Strategie AV21. and Luděk Svoboda.
The article presents a manuscript collection of texts of evangelical provenance that has recently been purchased in a German second-hand bookshop. According to a chronogram, this manuscript is likely to come from 1840. The manuscript consists of fifteen relatively independent text sections thematically related to the denominational controversies before and after the battle of White Mountain. The paper examines possible printed or manuscript models of individual parts and as well as their reflection in both earlier and more recent bibliographic literature. and David Mach.
Hexamerins are hemocyanin-related haemolymph proteins that are widespread in insects and may accumulate to extraordinarily high concentrations in larval stages. Hexamerins were originally described as storage proteins that provide amino acids and energy for non-feeding periods. However, in recent years other specific functions like cuticle formation, transport of hormones and other organic compounds, or humoral immune defense have been proposed. During evolution, hexamerins diversified according to the divergence of the insect orders. Within the orders, there is a notable structural diversification of these proteins, which probably reflects specific functions. In this paper, the different possible roles of the hexamerins are reviewed and discussed in the context of hexamerin phylogeny., Thorsten Burmester, and Lit