Ueber Symbiose von Bacterien (in Zoogloeaform) mit der Alge Gleocapsa polydermatica. Ktz

Ohne Zusammenfassung     

Buchbesprechungen

Ohne Zusammenfassung     

Computer simulation of an ideal lateral inhibition function

A model for lateral inhibition is presented in the context of the auditory channel. The mechanical analyzing system of the inner ear cannot alone account for the frequency resolution of hearing. Some additional mechanism, possibly lateral inhibition located in the auditory neural network, is needed to achieve the frequency selectivity observed in electrophysiological and psychoacoustical experiments. In a computer simulation study, the shape of an ideal lateral inhibition function was obtained. Such a function is applicable to all sensory modalities. In hearing, this function permits the sharpest possible frequency resolution as it can completely remove the frequency desharpening effect of the mechanical properties of the basilar membrane. In vision, it can compensate for abberations caused by the imperfections of the optical system of the eye.An expanded version of a paper presented at the XIth Intenational Congress on Acoustics, Paris, 1983     

Enzymic synthesis ofL-Lysine fromDL-α-Amino-ε-caprolactam by new microbial strains

The production of L-lysine fromDL-α-amino-ε-caprolactam (DL-ACL) by new strains producingL-α-amino-ε-caprolactamase and aminocaprolactam racemase is described. Optimal conditions for hydrolysis ofL-ACL byCryptococcus sp. and for racemization of ACL by cells of a strain isolated in nature and identified asPseudomonas sp. were determined. Synthesis ofL-α-amino-ε-caprolactamase is induced byDL-ACL orL-lysine with the same effectivity. A positive effect of phosphates (potassium salts) on reduction of the induction lag was detected, the synthesis of this enzyme was found to be repressed by glucose and some possibilities of the reversion of this repressive effect were demonstrated. Under conditions optimal for the production of both enzymes a quantitative theoretical conversion of 10 % aqueousDL-ACL toL-lysine by a mixture of native cells in a mass ratio of 1: 2 (producer of ACL-hydrolase to producer of ACL-racemase) occurred in 8 h at 40 °C and pH 8.0     

Aspermatogenic effect of the bull seminal ribonuclease (BS RNase) in the presence of anti-BS RNase antibodies in mice

Injection of mouse scrotum with the bull seminal ribonuclease (BS RNase) isolated from bull seminal vesicle fluid inhibited spermatogenesis and caused a decrease in the weight of the testes. Long-term injection of BS RNase evoked the production of antibodies which reached the titre 524448. These antibodies did not prevent the aspermatogenic action of BS RNase in vivo when a twofold higher amount of this enzyme was injected into mouse scrotum. Aspermatogenesis was reversible in both the first and second part of the experiment. During the period of aspermatogenesis the males were sterile. Increasing the amount of BS RNase injections in the second part of experiments caused aspermatogenesis around 3 months. No malformations were observed among offspring of males recovered from the first stage of aspermatogenesis. The antigen—antibody complex prepared in vitro and injected into testes of mice evoked the same degree of aspermatogenesis as the enzyme itself.     

From Regional to National Clouds: TV Coverage in the Czech Republic

Media, and particularly TV media, have a great impact on the general public. In recent years, spatial patterns of information and the relevance of intangible geographies have become increasingly important. Gatekeeping plays a critical role in the selection of information that is transformed into media. Therefore, gatekeeping, through national media, also co-forms the generation of mental maps. In this paper, correspondence analysis (a statistical method) combined with cloud lines (a new visual analytics technique) is used to analyze how individual major regional events in one of the post-communist countries, the Czech Republic, penetrate into the media on a national scale. Although national news should minimize distortions about regions, this assumption has not been verified by our research. Impressions presented by the media of selected regions that were markedly influenced by one or several events in those regions demonstrate that gatekeepers, especially news reporters, functioned as a filter by selecting only a few specific, and in many cases, unusual events for dissemination.     

Pinocytic uptake and intracellular degradation of N-(2-hydroxypropyl)methacrylamide copolymers a potential drug delivery system

Synthetic ¹²⁵I-labelled N-(2-hydroxypropyl)methacrylamide copolymers containing four different, potentially degradable peptidyl side chains were incubated with rat visceral yolk sacs cultured in vitro. All copolymers were captured by fluid-phase pinocytosis and three of the side chains were susceptible to lysosomal hydrolysis, resulting in release of [¹²⁵I]iodotyrosine back into the culture medium. Uptake and degradation was completely inhibited by 2,4-dinitrophenol. The thiol-proteinase inhibitor leupeptin did not affect the rate of pinocytosis, but caused different degrees of inhibition of hydrolysis depending on side chain composition.