A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Delivery of secreted placental alkaline phosphatase (SEAP) gene in vitro and in vivo as a component of recombinant avian adenovirus (CELO)

Recombinant adenoviruses capable of expressing the gene of secreted placentary alkaline phosphatase (SEAP) under control of CMV-promoter was obtained on the basis of CELO avian adenovirus and human adenovirus-5 (Ad5) genomes. The efficiency of the CELO vector was determined in experiments with transduction of human (293, A549, and H1299), mouse (B16), and avian (LMH) cell cultures. It was shown in C57BL/6 mice in vivo that SEAP gene is expressed under conditions of intravenous, intranasal, and intratumoral application of recombinant adenovirus CELO-SEAP. The duration of expression of the alkaline phosphatase CELO = SEAP gene in immunocompetent mouse body was 21 days. The level of SEAP gene expression was measured in the allantois fluid of chicken embryo infected with recombinant adenovirus CELO-SEAP.     

Cultivation of reaggregated brain cells in rapidly rotating mini-rollers

An original method of cultivation of reaggregated brain cells with the aid of high-speed portable mini-rollers is described. The mini-roller consists of parallel rollers and an electric motor rotating the flasks at a speed of 60 to 70 rpm. The Moscona technique was used for preparing brain cell suspensions. During cultivation of the suspension of dissociated cells in high-speed mini-rollers, reaggregates with an internal organotypic structure were obtained. The method suggested provides stable and reproducible results.     

Scalable and flexible inference framework for stochastic dynamic single-cell models

Understanding the inherited nature of how biological processes dynamically change over time and exhibit intra- and inter-individual variability, due to the different responses to environmental stimuli and when interacting with other processes, has been a major focus of systems biology. The rise of single-cell fluorescent microscopy has enabled the study of those phenomena. The analysis of single-cell data with mechanistic models offers an invaluable tool to describe dynamic cellular processes and to rationalise cell-to-cell variability within the population. However, extracting mechanistic information from single-cell data has proven difficult. This requires statistical methods to infer unknown model parameters from dynamic, multi-individual data accounting for heterogeneity caused by both intrinsic (e.g. variations in chemical reactions) and extrinsic (e.g. variability in protein concentrations) noise. Although several inference methods exist, the availability of efficient, general and accessible methods that facilitate modelling of single-cell data, remains lacking. Here we present a scalable and flexible framework for Bayesian inference in state-space mixed-effects single-cell models with stochastic dynamic. Our approach infers model parameters when intrinsic noise is modelled by either exact or approximate stochastic simulators, and when extrinsic noise is modelled by either time-varying, or time-constant parameters that vary between cells. We demonstrate the relevance of our approach by studying how cell-to-cell variation in carbon source utilisation affects heterogeneity in the budding yeast Saccharomyces cerevisiae SNF1 nutrient sensing pathway. We identify hexokinase activity as a source of extrinsic noise and deduce that sugar availability dictates cell-to-cell variability.     

Glio-neuronal aggregates in collagen gel: a model for studying the factors affecting development of central nervous system cells

Glio-neuronal aggregates of dissociated cells obtained from embryonic brain during cultivation in rotating flasks were transfered for further cultivation into collagen gel, containing balanced salt solution, serum-free amino acid medium, or complete nutrient medium. Active neurite growth and glial cell migration were observed during cultivation in collagen gel. The experiments have shown that glio-neuronal aggregates may serve as an experimental model for testing the activity of different neuronotrophic and neurite growth stimulating factors.