Variances in the levels of serum lysozyme in X-irradiated mice

The level of serum lysozyme in mice varies in relation to the dose of irradiation in several phases. High doses result in a progressive decrease whereas a decrease on the first and about the ninth day is observed after irradiation with lower doses. A rise in lysozyme level occurs on the third day. Enhancement of lysozyme levels was observed after application of 20—50 r. Administration of lysozyme did not affect the deaths of mice receiving with massive doses of irradiation.     

The efficacy of the antibacterial peptide,pyrrhocoricin, is finely regulated by its amino acid residues and active domains

Summary Pyrrhocoricin, a highly active antibacterial peptide isolated from insects, inhibits chaperone-assisted protein folding via binding to the 70 kDa heat shock protein DnaK with its amino terminal half. The C-terminus functions as an intracellular delivery module. In the current study, chimeras consisting of the putative functional units of pyrrhocoricin and a related peptide, drosocin, were made, and it was found that some mixed and matched sequences retained their ability to killEscherichia coli, Salmonella typhimurium andAgrobacterium tumefaciens. While pyrrhocoricin appeared to have a more universal pharmacophore, drosocin featured a more robust intracellular delivery unit. We also identified the minimal length of pyrrhocoricin that is needed to efficiently kill bacteria. While for activity againstS. typhimurium the peptide could not be shortened, againstE. coli it was sufficient to have a Vall-Ile16 amino-terminal fragment. Although Vall was not part of the Asp2-Pro 10 pharmacophore (it could be replaced with other residues), it could not be eliminated and apparently played an important role in defining the activity of the peptide. Indeed, when Val1 was replaced with lysine, not only the efficacy of pyrrhocoricin to kill the sensitive strains increased significantly, resulting in the most active antimicrobial peptide against some clinical strains ever made, but the modified peptide was also able to killPseudomonas aeruginosa, an originally unresponsive bacterium in the low μg ml⁻¹ concentration range. However, this substitution likely influenced the interaction with bacterial membranes rather than that with the target protein, and therefore the dominant mode of action of the Lysl-pyrrhocoricin peptide may feature membrane disintegration instead of DnaK inhibition.     

Bausteine zu einer vergleichenden Physiologie der lokomotorischen Reflexe bei fischen

Zusammenfassung Es wird (S. 223,224) auseinandergesetzt, aus welchen Gründen ein vergleichendes Studium der Rückenmarksreflexe bei Fischen verlohnt, und was für allgemeine Schlüsse am Ende einer Untersuchung möglichst zahlreicher Fischtypen beantwortet werden können.Die allgemeinen Richtlinien, nach denen die geplante Untersuchung durchgeführt werden soll, werden angegeben.In dieser I. Mitteilung sind 3 Typen: Crenilabrus, Sargus, Uranoscopus behandelt; es werden zahlreiche lokomotorische Reflexe beschrieben, ihre Abhängigkeit von Reizart, Reizstärke und Reizort und ferner von der Höhe der Rückenmarksdurchtrennung dargestellt. Die Ergebnisse finden sich jeweils am Schluß der einzelnen besprochenen Typen.Naples Biological Scholar, and Senior Hulme Research Scholar.     

A review of the alien and expansive species of freshwater cyanobacteria and algae in the Czech Republic

The invasion and spread of non-native species of many different kinds of organisms is of increasing interest to researchers. Invasions by microscopic organisms, however, are poorly understood, and their impact on the environment is probably underestimated. We collected available data on non-native and invasive/expansive algae and cyanobacteria in the Czech Republic; we mapped their distribution and assessed their impact on local species and other real or potential risks resulting from their spread. The list of alien species in the Czech Republic contains 10 species of cyanobacteria, 9 species of Bacillariophyceae, 1 species of Dinophyta, 1 species of Ulvophyceae, 2 species of Chlorophyceae, and 1 species complex of Zygnematopyceae. The literature on the worldwide occurrence of these taxa is also reviewed.