Construction of peptide mimetics of an epitope of the human immunodeficiency virus (HIV-1) gp41 protein, recognized by virus-neutralizing antibodies 2F5

A phase peptide library was screened with virus-neutralizing monoclonal antibodies (MCA) 2F5 which recognize a conserved epitope of HIV-1 gp41. Phages that expose peptides specifically binding with MCA 2F5 were selected by ELISA. Amino acid sequence analysis revealed a homology to region 662-671 of HIV-1 HB10 gp160 for most peptides. The major role in recognition was ascribed to Asp-664, Lys-665, and Trp-666. The epitope-mimicking peptides were tested for immunogenicity. Antibodies to gp41 were detected in serum of immunized rabbits.     

Comparative evaluation of the efficacy of Borrelia indication in ixodes ticks (Ixodidae) using dark field microscopy and polymerase chain reaction (PCR)

Indication of Borrelia (B. burgdorferi sensu lato) in 205 adult unfed I. persulcatus ticks from a natural focus was carried out simultaneously by methods of PCR and dark-field microscopy of vital preparations. PCR method revealed Borrelia prevalence in considerable number of ticks, in which Borrelia were not found by microscopy of 250 microscopic fields in a preparation from each individual tick. At the same time, PCR method didn't give positive results for approximately 8% of ticks, which contained rather high concentration of Borrelia (more than 10 per 100 microscopic fields). In general, PCR method doesn't have advantages in comparison with a microscopy of vital preparations for study the Borrelia prevalence in ticks.     

On the development of body-wall musculature Diplostomum chromatophorum metacercariae (Trematoda: Diplostomidae)

The body-wall musculature of invasive cercariae and metacercariae of Diplostomum chromatophorum at different intervals after the penetration into the experimental intermediate host Cyprinus carpio (1, 3, 5, 6, 7, 10, 12, 20, 34, 40 days) has been investigated with the help of TEM technique. During the first 10 days after the invasion (in conditions of our experiment), the cercarial subtegumental muscle fibres degenerate. These muscles are replaced by newly formed ones. Mass differentiation of myoblasts beneath the tegument was observed in 7-10-day-old metacercariae. Obtained data indicate the metamorphosis of body-wall musculature during the morphogenesis in Diplostomum chromatophorum metacercariae.     

Asymmetric responses of epicardial and endocardial fibers of the dog atrium to cholinergic effects

The ACh shortened the AP in canine epicardial and endocardial cells, the effect being more obvious in the latter. The findings suggest that 4-aminophyridine-sensitive transient outward current is expressed in canine atrial epicardial and endocardial cells, that the ACh exerts direct effects on epicardial and endocardial AP duration, that differential responses of epicardial and endocardial AP duration to the ACh may alter the gradient of repolarisation across the atrial wall and contribute to the vagus-indoced atrial flutter and fibrillation.     

Comparative study of the reactability of phosphoric acid residues in tRNA(Ser) and tRNA(Leu) from Thermus thermophilus

The reactivity of phosphates in the Thermus thermophilus tRNA(Ser) (GCU) and tRNA(Leu) (CAG) was studied using the ethylnitrosourea modification. It was shown that phosphates of nucleotides 58-60 (T loop), 20-22 (D loop), and 48 (at the junction of the variable and T stems) were poorly modified in both tRNAs. The most pronounced differences in the reactivity were observed for phosphates at the junctions of the variable stem with T-stem (47q, 49) and anticodon stem (45). This indicates differences in orientations of the long variable arm relative to the backbone in the tRNAs studied.