The ultrastructural cytology and reproduction of Amphiacantha longa Caullery et Mesnil, 1914 is described. Mcrogonial reproduction was not observed. The sporogony follows two lines: free disporoblastic. and enveloped, polysporoblastic, involving sporoblast mother cells. The enveloped sporogony is endogenous in spore sacs of sporont origin, daughter cells are formed by vacuolation. Probably all stages have coupled nuclei. Both free and enveloped spores are equipped with an extrusion apparatus composed of a flat polar sac, a straight polar filament of manubrium type, and a posterior globular appendix. Manubrium and appendix are enclosed in a membraneous coat. Circular elements of coat material occur in the proximity of the extrusion apparatus. The membraneous coat and the surface layer of the manubrium penetrate the polar sac. The extrusion apparatus is located at the wide pole of the spore, the nuclei at the narrower pole. Hosts are gregarines of the genus Lecudina Mingazzini, living in the gut of the polychaete Lumbrinereis fragilis (O. F. Muller). The cytology and reproduction are discussed and compared to other genera of metchnikovellideans, to the chytridiopsid genera, and to microsporidia expressing the typical cytology for the group. Metchnikovellideans and chytridiopsids exhibit cytological and reproductive similarities. The species is redescribed, the diagnosis of the genus Amphiacantha Caullery et Mesnil, 1914 is emended, and the new family Amphiacanthidae, comprising the genera Amphiacantha and Amphiamblys Caullery et Mesnil, 1914, is established.
The aim of this paper is to explore the impact of the structure of the Czech education system on the development of the relationship between a student's achievement and his/her family background. It compares the strength of the relationship between student achievement and a student's family background in various stages of his/her education career (grades 4, 8 and 10) in the Czech Republic and in systems without early tracking that also exhibit high student performance (Canada, Nordic countries). In addition, the paper tests a hypothesis that systems with different levels of tracking differ not only in their structure but also in teaching methods and teachers' attitudes. The analysis was conducted on data sets from the IEA PIRLS 2001, the IEA TIMSS 1999, and the OECD PISA 2003.
In Phaseolus and Robinia leaves, direct light reaction (de-epoxidatíon of violaxanthín) was inhibited during 7-9 h as an aftereffect of y-radiation (167 mGy s'*). Complete suppression of the light reaction by the de-epoxidation was reached after 12-14 h. The suppression of xanthophyll de-epoxidation reflects the inhibitíon of photosynthetic electron transport chain and may be ušed for testing deleterious efifects on plants.
Under certain conditions the isolated reaction centre (RC) of photosystem 2 (PS 2) ís highly vulnerahle to photoinduced damage. With no added secondary electron acceptors or donors tíďs damage is due to singlet oxygen generated by the P680 triplet. This triplet is formed by recombination of the radical pair PóSO+Pheo' and Ihe photoinduced damage only occurs under aerobic conditions. When an electron acceptor is present, the degradation of pigments and the Dl and D2 proteins is due to formation of P680+ and secondary oxidation processes. Under the latter but not the former condition, characteristic pattems of degradation firagments of the Dl and D2 proteins are observed. In particular 24 and 17 kDa breakdown firagments of Dl are obtained while the D2 protein yields firagments having molecular masses of 29 and 21 kDa. Experiments involving the use of antibodies, radiophosphate and speciííc proteolytic digestion indicate that all four firagments contain the C-terminal portions of their mature proteins. These findings indicate that the proteolytic cleavage sites are positioned on the lumenal side of the membrane, particularly in the region spanning transmembrane helices I and II. Related studies on the 24 lď)a Dl protein fragment generated in vivo using Synechocystis sp. PCC 6803 by photoinhibitory treatment give the same conclusion for this firagment. Such a conclusion seems to contrast with the previous suggestion that the initial cleavage of Dl protein associated with its degradatíon and tumover occurs on the outer side of membrane in the region spanning transmembrane helices IV and V.
The detection of the Kautsky effect, i.e. the chlorophyll (Chl) fluorescence índuction kínetics induced in the dark-adapted leaves because of a sudden irradiation, by Hans Kautsky and his students is reviewed here on the occasíon of the 60* anniversary of this CW fluorescence transient discovery and oftBě 100* birth anniversary of Hans Kautsky in 1991.
Expanding the domain of majority rule is widely seen as desirable for the European Union. But the functioning of majority rule depends on preconditions that are seldom taken into account. The basic precondition is that overruled minorities accept majority decisions instead of exiting the voting unit. The specific problem of applying majority rule in the European Union is that overruled minorities at the European level are majorities at the nation-state level. By distinguishing between three dimensions of conflicts - content, time and space - the article analyses under what conditions it is possible to expect minorities to accept majority decisions, thus enabling the resolution of conflict by majority rule at the European level.
Using the localization of nonspecific esterases, the nervous system of Polystoma indicum Diengdoh et Tandon, 1991 could be revealed in toto. The nervous system is bilaterally symmetrical. Cerebral ganglia, which are connected by a thick dorsal commissure, are present dorsal to the pharynx. From the cerebral ganglia arise five anterior pairs and four posterior pairs of nerve trunks. The anterior nerves and/or their fine branches join to form a conspicuous circumoral nerve ring complex. The posterior nerves unite in the opisthaptoral region to form two main haptoral nerves, the branches from which innervate the components of the opisthaptor. Presence of nerve cells is also revealed in association with the main nerves, more predominantly in the vicinity of the opisthaptoral suckers.