Etiologic role of bacteria of the genus Providencia in acute intestinal diseases

A study was made of morphological, cultural, biochemical properties and antigenic structure (by O-antigen) of 59 strains isolated in group acute intestinal affection of children at the pioneer camp. By the combination of biochemical properties (31 tests) all the cultures isolated were referred to Providencia alcalifaciens of biotype 7. Serological typing with the aid of experimental diagnostic agglutinating O-sera showed these strains to be referred to serological group O2. Identity of the O-antigen of the isolated cultures to the standard O2 strain was confirmed by the results of cross reactions of agglutinin absorption. The results of bacteriological and clinico-epidemiological studies offered a possibility of regarding the isolated Providencia alcalifaciens of serological group O2 as the causative agents of the group intestinal disease in children.     

Multi-Type Galton-Watson Process As A Model For Proliferating Human Tumour Cell Populations Derived From Stem Cells: Estimation of Stem Cell Self-Renewal Probabilities In Human Ovarian Carcinomas

Abstract. A mathematical model for proliferation of tumour cell populations is developed. the cell population is assumed to be organized in a hierarchy of decreasing proliferative potential and increasing degree of differentiation. Using some elements of the theory of Multi-type Galton-Watson processes, a method is proposed for the estimation of P_sr, the probability of self-renewal of tumour stem cells, from the experimental distribution of clonal unit sizes obtained in cell culture studies. Six data sets from patients with advanced adenocarcinorna of the ovary are used to demonstrate the method. Reasonable estimates are obtained, and the theoretical colony size distributions predicted by the model appear to be in good qualitative agreement with the experimental ones, and lend support to a stem cell model of tumour growth. the possible significance of P_sr as a prognostic factor is briefly discussed.     

Conditioning adhesive contacts between the neutrophils and the endotheliocytes by Staphylococcus aureus

We have developed a model for evaluating the integral intercellular interactions in the “endotheliocyte‐neutrophil” system and have shown the high variability of adhesion contacts in different donors associated with different expression profiles of neutrophils. Two methods (forсe spectroscopy‐spectroscopy and scanning ion‐conductance microscopy) showed a decrease in the rigidity of the membrane‐cytoskeletal complex of neutrophils under the influence of Staphylococcus aureus 2879 M. Adding this strain to the “endotheliocyte‐neutrophil” system caused a statistically significant decrease in the adhesion force and adhesion work, which indicates a change in the expression profile and physicochemical properties of membranes of both types of interacting cells (neutrophils and endotheliocytes).     

Investigation of Adhesive Intercellular Contacts of Neutrophils and Lymphocytes by Atomic Force Microscopy

Biophysics - Abstract—Atomic force microscopy was used to create a system for measuring intercellular adhesion. Scanning electron microscopy was applied to confirm that poly-L-lysine is the...     

Comparative analysis of memory pathologies of various genesis: epileptic patients and Chernobyl nuclear plant accident liquidators

Different types of short-term memory were examined in two groups of people: epileptic patients during remission and participants of cleaning after the incident at Chernobyl nuclear power plant. The control group matched the experimental groups by sex, age, and education. It was found that memory dysfunctions were similar independently of the kind of pathology. The associative memory was most vulnerable. This finding is explained in terms of the role of protein-nucleic synthesis (the molecular-universal aspect) in the formation of human and animal associative memory.     

Dynamics of formation and morphological features of neutrophil extracellular traps formed under the influence of opsonized Staphylococcus aureus

In the process of performing their protective functions, neutrophils can form neutrophil extracellular traps (NETs), consisting of DNA in combination with enzymes and histones. The aim of the study was to determine the dynamics of the formation of NETs under the influence of opsonized Staphylococcus aureus and to determine the morphological features of their development in real time by atomic force microscopy. It was found that the maximum formation of NETs was observed after 3 hours of co‐incubation of neutrophils and opsonized S. aureus. For the first time, the atomic force microscopy method revealed that, at first, large blocks of parallel DNA helices are formed, which then spread in waves, and only then their bifurcation and separation can be observed. Some of the strands formed are covered by a shell, which subsequently completely disappears. Enzymes and histones become clearly visible only after 140 to 150 minutes of observation. The DNA helixes move toward the opsonized S. aureus. After NET formation, the cell remains on the substrate only in the form of traces of focal adhesion. This, and the fact that the maximum amount of NETs is formed after 3 hours of co‐incubation with opsonized S. aureus, suggests that the formation of NETs follows the classical mechanism. The study of the dynamics of formation and the microstructure of NETs makes it possible to estimate the time frame for the implementation of this protective mechanism of the human body when performing the compensatory inflammatory reaction.     

Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.