The posterior attachment organ (sucker) of Temnocephala sp. is located ventrally attached to the posterior end of the body by a well defined stalk; those of Udonella caligorum Johnston and Anoplodiscus cirrusspiralis Roubal, Armitage et Rohde are extensions of the posterior end facing posteriorly. In Philophthalmus, the sucker is ventrally embedded in the main body. The sucker of Temnocephala is lined by an epidermis, its ventral part separated from the adjacent epidermis by a septate junction. The epidermis resembles that of the body proper, containing nuclei and numerous dense bodies, its surface enlarged by short microvilli, traversed by glandular ducts of two types and by sensory receptors, and based on a basal lamina with a thick underlying fibrous matrix. The stalk of the sucker contains many muscle fibres extending from the main body into the sucker. The posterior surface of the sucker of Udonella is separated from the adjacent tegument by a septate junction; it consists of numerous microvilli arising from the basal lamina and does not represent a tegument; glandular ducts of two types open through it, and muscle fibres extend from the body proper into the sucker. The posterior surface of the sucker of Anoplodiscus consists of a thin tegument not separated from the adjacent tegument by a septate junction, drawn out into a very large number of densely packed, long microvilli, some branching from a thick cross-striated base; large glandular ducts open postero-laterally. The ventral sucker of Philophthalmus is embedded in the body proper but clearly bounded by a “capsule” of basal lamina; it is lined by a tegument continuous with that of the main body and lacking microvilli except in a small band around the ventral sucker opening. There is no evidence from ultrastructure that the stickers of the four taxa are homologous. Since there is no convincing other evidence for the homology of the posterior attachment organs of the major groups of parasitic Platyhelminthes (Neodermata) and the Temnocephalida, a “cercomer theory” assuming such homology cannot be accepted as proven.
Diurial variations in leaf conductance for water vapour (g^), and in rates of net photosynthesis (P^) transpiration (P) were investigated for individual Fagus crenata, Ginkgo biloba and Alnus firma trees during the growing season (May 12, June 3, August 19 and October 22, 1992), to defme the effects of main climatic factors limiting the photosynthetíc capacity of leaves. Measurements were undertaken at 1 h intervals in fully expanded leaves from 04.00 to 20.00 under sunny day and favourable water supply. Diumal patterns of gg and P^ in F. crenata were similar to G. biloba, showing strong dependence on irradiance in the early moraing and early evening, in May, June and August. The maximum values of P^, gg and water-use eíTiciency (WLIE) were recorded at 07.00 to 08.00 when photosynthetícally active radiation (PAR) and leaf temperature (Zj) were approximately 1200 pmol m'^ s"' and below 25 °C, respectively. P^, gg and WUE decreased from 08.00 to 13.00 contínuously, followed by a slight recovery at about 17.00 and a steep dechne until darkness. A. firma remained at maximum P^ from 07.00 to 14.00, and P^, gg and E were much higher than for the other two species. The peak of E in all three species always occurred at midday, coincident with maximum PAR and highest Ty But in October, P^ and E in all three species were highest around noon, also parallel to the maximum PAR and Ty
Forty soil samples from forests and other biotopes in Germany and the Czech Republic were studied for the presence of entomopathogenic nematodes using the Galleria bait method at the same time as a sieving-decanting method for direct extraction of infective-stage juveniles. Five Steinernema species were recovered trom the samples from Germany and four species from the samples from Czechia. All five species were recovered with both methods, but the baiting technique was generally less effective and mixtures of species were frequently undetected. The direct extraction method provided quantitative estimates of infective-stage juvenile density but no information on their infcclivity or on morphological characters of adults, and nematode cultures could not be established.
In whole cells of the wild type of Synechocystis 6714 exposed to high irradiance (Hl) the electron transfer to Qb was inhibited before the transfer to Qa In the mutant AzV with two point mutations in the Qg pocket (Ala 251 Val and Phe 211 Ser) the inhibition of electron transport to Qb had about the same rate as in the wild type but the transport to Qa was inhibited faster in the mutant. In the mutant also the repair of photosystem 2 (PS 2) reaction centres was slower after a moderate photoinhibitory damage. In contrast degradation of the Dl protein in the course of photoinhibition in vitro was slower with thylakoids from the mutant than with those of the wild type. In CMamydomonas cells photoinhibited at low temperature (5 °C) and in spinách thylakoids under anaerobic conditions a fast inhibition of electron transfer developed in PS 2 simultaneously with a State characteiized by a high level of F^. This high fluorescent statě disappeared and electron transport activity was restored in the dark without protein synďiesis when photoinhibited samples were soon transferred to higher temperature (25 °C) or to aerobic conditions, respectively. On the other hand, the irreversible photoinhibitory damage characteiized by the dechne of was slowed down by lowering of the temperature in all the objects tested.
Salivary gland extracts (SGE) from unfed and 5 days led adult female Ixodes ricinus (Linnaeus, 1758); Haemaphysalis inermis (Birula, 1895) and Dermacentor reticulatus (Fabricius, 1794) ticks were prepared. The protein content after feeding increased by 10.6, 8.7 and 6.8 limes, respectively. Extracts were equilibrated to the same protein content and submitted to SDS-polyacrylamide gel electrophoresis followed by computer analysis of the scanned gels. Relative differences in protein profiles of extracts obtained from unfed and partially fed ticks were found in all species and some of them were similar in all three species used in the study. Results demonstrate that the increase of the protein content in salivary glands during the feeding does not occur proportionally. Some proteins are synthesised preferentially (67.1 kDa, 13.5 kDa) but other bands (in range of 15-16 kDa) present in the SGE derived from unfed ticks arc less discernible in that of fed ticks.
The patterns of random amplified fragments and molecular karyotypes of 12 isolates of anuran trypanosomes continuously cultured in vitro were compared by random amplified polymorphic DNA (RAPD) analysis and pulsed field gradient gel electrophoresis (PFGE). The time interval between preparation of two series of samples was one year. Changes were not observed in the number and size of sharp, amplified fragments of DNA samples from both series examined with the ten primers used. Likewise, changes in the molecular karyotypes were not detected between the two samples of these isolates. These results suggest that the molecular karyotype and the RAPD patterns of the anuran trypanosomes remain stable after being cultured continuously in vitro for one year.
Interspecific competition between fat hen (Chenopodium album L.) and sunflower (Helianthus annuus L. NSH-33 hybrid) in pure and mixed stands of identical plant density (35 x 35 cm spacing) was studied in smáli plot field experiments under drought stress. Decrease in net photosynthetic rate (E^) due to interspecific competition was not statistically significant in either species in the first part of the growing season. During drought stress, however, significantly decreased in sunflower, while it hardly changed in C. album in the same (interspecific) competition situation. In pure stands, transpiration rate (E) was lower in C. album than in sunflower and this difference was more pronoímced in mixed stands. Consequently, C. album showed a very high water use efficiency (WUE) especially in the shade layer, which accounts for a larger part of the canopy in this species. By contrast, WUE in sunflower decreased, especially in the sun layer of the mixed stand. Interspecific competition reduced the total biomass more severely in sunflower than in C. album by the end of the growing season. The reduction was especially remarkable in the biomass of the reproductive organs. Reproductive effort expressed as reproductive allocation was higher in C. album than in sunflower. Hence the reproductive effort in sunflower and C. album in both intra- and interspecific competition seemed to be correlated with WUE, which is a prime characteristic of drought stress tolerance.
Short-term thymectomized (two months after thymectomy) adult rainbow trout, Oncorhynchus mykiss (Walbaum) infected with the flagellate Cryptobia salmositica Katz, 1951 responded well during primary infection with C. salmositica and recovered fish also showed secondary response (rapid production of complement fixing antibody after homologous challenge) five months after recovery. Complement fixing antibody was detected during primary and secondary responses and the titres of complement fixing antibody in thymectomized fish were significantly lower than those in infected intact fish. The parasitaemia in thymectomized infected fish was significantly lower than in intact infected fish. Both recovered thymectomized fish and intact fish were protected from cryptobiosis when they were challenged. Similarly, long-term thymectomized fish (nine months after thymectomy) vaccinated with an attenuated strain of C. salmositica were protected from cryptobiosis. There were no significant difference (P > 0.05) in parasitaemia, packed cell volume and complement fixing antibody titres between vaccinated/challenged thymectomized and vaccinated/challenged intact fish. Hence, thymectomy in adult rainbow trout did not decrease the detectable complement fixing antibody against C. salmositica in long-term thymectomized fish but reduced the detectable protective antibody in short-term thymectomized fish.
Práce vznikla jako součást projektu zabývajícího se zkoumáním konstantnosti větných členů mezi angličtinou a češtinou. Cílem výzkumu je ověřit hypotézu o univerzální platnosti principu koncového postavení jádra výpovědi. Vzhledem k odlišné typologické charakteristice angličtiny očekáváme, že pro zachování téhož lineárního uspořádání prvků výpovědi bude užívat odlišné syntaktické struktury.
Vc směru z angličtiny do češtiny byly nejčastčjšími nekorespondujícími ekvivalenty předmětu české adverbiale, přísudek a podmět. Vzhledem к volnému slovosledu češtiny zde ovšem aktuální členění větné nepatřilo mezi přímo působící faktory, jeden z hlavních faktorů je však tendencí к základnímu rozložení VD podmíněn. Naopak ve směru z češtiny do angličtiny bylo AČV zásadním faktorem změny předmětu v podmět, jež tvořila téměř polovinu všech případů, a přispívalo rovněž к disociaci slovesného přísudku. Rozložení stupňů výpovědní dynamičnosti zůstalo v obou směrech většinou zachováno a blížilo se základnímu rozložení VD. Výsledky práce potvrzují zkoumanou hypotézu.