Allergic encephalomyelitis in guinea pigs on the intracutaneous and subcutaneous administration of fragment 114-122 of the human myelin cationic protein

Single intracutaneous injection of 30 micrograms of human basic myelin protein peptide 114-122 (H-Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Arg-OH) with Freund adjuvant induced the onset of encephalomyelitis on day 9-19 after the injection. The lethality was 33%. In autumn the disease was more severe than in summer.     

The influence of extremely weak alternating magnetic fields on the regeneration of planarians and the gravitropic response of plants

The influence of extremely weak alternating magnetic fields (EW AMF) directed collinearly to the static Earth magnetic field on the rate of regeneration of planarians and the rate of gravitropic response in the stem segments of flax has been studied. The value of bioeffects of EW AMF is determined by the parameter γB _AC/f, where γ is the gyromagnetic ratio of the magnetic moments induced by the orbital movements of electrons in atoms, and B _AC and f correspond to magnetic induction and frequency of the alternating magnetic component. It was shown that the magnitude of bioeffects depends on the amplitude (at fixed 1000 Hz — frequency) and frequency (at fixed 192 nT — amplitude) of the alternating component. Maxima of bioeffects are observed at γB _AC/f = 0.9; 2.75, and minor maxima γB _AC/f = 4.5; 6.1. The bioeffects are absent at γB _AC/f =1.8, 3.8, 5.3, 6.7. The positions of the maxima and minima of bioeffects correspond to the theoretical prediction (at γ = 14000 Hz/μT). Primary targets for the EW AMF of this type are the magnetic moments induced by the orbital movements of electrons in atoms.     

Distribution of coccidians (Coccidea) among different groups of hosts

Approximately 3660 species of Coccidea belonging to 73 genera and 29 families parasitize representatives of the Metazoa kingdom. Coccidea were discovered in 10 of 35 phyla of Metazoa; in the most cases a direct correlation between the number of species in a host group and the number of Coccidea known from that group is clearly traced. Host groups, which are most archaic phylogenetically, are also parasitized by the archaic Coccidea groups. Evolutionarily derived hosts are parasitized by groups of Coccidea, which are the youngest phylogenetically. Parallel development of Coccidea and their hosts may be used for an indirect determination the time of origin of different Coccidea groups.     

Ribosomal and non-ribosomal resistance to oxazolidinones: species-specific idiosyncrasy of ribosomal alterations

A derivative of Mycobacterium smegmatis, which carries only one functional rRNA (rrn) operon, was used to isolate mutants resistant to the ribosome-targeted antibiotic linezolid. Isolation and characterization of linezolid-resistant clones revealed two classes of mutants. Ribosomes from class I mutants are resistant to oxazolidinones in an in vitro peptidyl transferase assay, indicating that resistance maps to the ribosome component. In contrast, ribosomes from class II mutants show wild-type susceptibility to a linezolid derivative in vitro, pointing to a non-ribosomal mechanism of resistance. Introduction of a wild-type ribosomal RNA operon into linezolid-resistant strains restored linezolid sensitivity in class I mutants, indicating that resistance (i) maps to the rRNA and (ii) is recessive. Sequencing of the entire rrn operon identified a single nucleotide alteration in 23S rRNA of class I mutant strains, 2447G --> T (Escherichia coli numbering). Introduction of mutant rrl2447T into M. smegmatis rrn- resulted in a linezolid-resistant phenotype, demonstrating a cause-effect relationship of the 2447G --> T alteration. The 2447G --> T mutation, which renders M. smegmatis linezolid resistant, confers lethality in E. coli. This finding is strong evidence of structural and pos-sibly functional differences between the ribosomes of Gram-positive and Gram-negative bacteria. In agreement with the results of the in vitro assay, class II mutants show a wild-type sequence of the complete rRNA operon. The lack of cross-resistance of the class II mutants to other antibiotics suggests a resistance mechanism other than activation of a broad-spectrum multidrug transporter.     

Evidence for an early prokaryotic origin of histones H2A and H4 prior to the emergence of eukaryotes.

Histones have been identified recently in many prokaryotes. These histones, unlike their eukaryotic homologs, are of a single uniform type that is thought to resemble the archetypal ancestor of the eukaryotic histone family. In this paper we report the finding, the cloning and the phylogenetic analysis of the sequence of a prokaryotic histone from the hyperthermophile Methanopyrus kandleri . Unlike previously described prokaryotic histones, the Methanopyrus sequence has a novel structure consisting of two tandemly repeated histone fold motifs in a single polypeptide. Sequence analyses indicate that the N-terminal repeat is most closely related to eukaryotic H2A and H4 histones, whereas the C-terminal repeat resembles that found in prokaryotic histones. These results imply an early divergence within the histone gene family prior to the emergence of eukaryotes and may represent an evolutionary step leading to eukaryotic histones.     

The ultrastructure of Blastocystis galli from chickens

The ultrastructure stages of Blastocystis galli were studied in chicken's intestine and in laboratory cultures. There were found morphological structures: surface coat (cell from chickens' intestine showed a very thick surface coat); cell membrane--there were some small electron-opaque deepening "pockets" on the membrane; inner membrane; endoplasmic reticulum with attached ribosomes, which present in the cytoplasm; all cells contained numerous of small vacuoles and large glycogen inclusions in cytoplasm; mitochondria with tubular cristae; nucleus with granules condensed chromatin; central vacuole; Golgi complex was represented by number of plates grouped in a pite; the cyst-like forms were surrounded by multilayered wall.