Optimal allocation of building blocks between nutrient uptake systems in a microbe

 A bacterial cell must distribute its molecular building blocks among various types of nutrient uptake systems. If the microbe is to maximize its average growth rate, this allocation of building blocks must be adjusted to the environmental availabilities of the various nutrients. The adjustments can be found from growth balancing considerations. We give a full proof of optimality and uniqueness of the optimal allocation regime for a simple model of microbial growth and internal stores kinetics. This proof suggests likely candidates for optimal control regimes in the case of a more realistic model. These candidate regimes differ with respect to the information that the cells control system must have access to. We pay particular attention to one of the three candidates, a feedback regime based on a cellular control system that monitors only internal reserve densities. We show that allocation converges rapidly to balanced growth under this control regime. Received: 20 November 2000 / Revised version: 7 August 2001 / Published online: 21 February 2002     

Hepatitis B markers in southern Altaĭ inhabitants of the village of Mendur-Sokkon (the Republic of Altaĭ). HBsAg subtyping in hepatitis B virus isolates with monoclonal antibodies

Blood samples taken from 231 native inhabitants of the village of Mendur-Sokkon located in the Republic of Altai (South-Western Siberia, Russia) were tested for the presence of virus hepatitis B (HBV) markers. 31 samples (13.4%) were found to contain HBsAg, 111 samples (48.05%) were found to contain total anti-HBc antibodies, 123 samples (53.24%) were found to contain anti-HBs antibodies and 15 blood samples (6.49%), anti-HBc antibodies without anti-HBs antibodies and HBsAg. The age-dependent distribution of the occurrence of HBV markers among the aboriginal population of the South Altal remained unchanged (69.9 +/- 7.9%) for the last 50 years. The vertical and horizontal routes of HBV transmissions were noted. The data obtained in this study are indicative of a highly endemic character of HBV of the territory of Mendur-Sokkon. HBsAg-positive blood samples were taken for HBsAg subtyping with the use of a panel of monoclonal antibodies. Two subtypes of HBsAg were detected: ayw1-2 and ayw3varB with the occurrence of 92.6% and 7.4%, i.e. distributed in the ratio 25/2.     

tag7 Gene and gene therapy of cancer

Modern gene therapeutic approaches towards the treatment of malignant neoplasms are discussed. Specifically, results of the first experiments on the development of vaccines on the basis of tumor cells modified with various cytokines and activation molecules are described. We compare effectiveness of different cytokines used for modification of tumor cells are made and consider possible mechanisms of vaccine action. The reasons for impossibility of the development of effective endogenous antitumor immunity are examined. The results of comparative analysis of the Tag7 protein antitumor activity are presented. This evidence clearly shows that Tag7 is a promising agent for anticancer therapy.     

Experimental investigation of Ingavirin antiviral activity against human parainfluenza virus

The Ingavirin antiviral properties with respect to the parainfluenza virus, as an actual human respiratory tract pathogen, were investigated by two methods, i.e. immunoenzymatic analysis and microtetrazolium test. The results showed that along with the immediate antiviral activity Ingavirin had nonspecific cytoprotective properties. While affecting the virus proteins synthesis, Ingavirin lowered the virus cytopathogenic action. The drug significantly decreased the portion of the bronchial epithelium cells killed at the stage of acute infection.     

Molecular modeling of structure of eukaryotic ribosomal translation termination complex

Models of atomic structure of eukaryotic translation termination complex containing mRNA, P-site tRNAPhe, human class-1 polypeptide release factor eRF1 and 80S ribosome were constructed. The method of computational modeling was applied. The modeling was based on the functional and structural similarity between tRNA and eFR1 bound in the ribosomal A site. Structural template for the modeling was a known structure of the 70S ribosome complexed with mRNA, P- and A-site tRNAsPhe. The eRF1 molecule bound to the ribosome undergone substantial conformational changes resulting in the mutual configuration of the N- and M-domains similar to tRNA shape. Two models of binding of eRF1 to mRNA at the A-site in the presence of P-site tRNA were generated and characterized by a shape complementarity between the mRNA stop codon and grooves of the different sides of the molecular surface of the fragment of alpha2-helix, NIKS loop and alpha-helix of the N-domain. In the model 1 the stop-codon nucleotides were at the equal distances from the N- and C-domains. In the model 2 the stop-codon was proximal to the NIKS and YxCxxxF motifs of the N-domain. Both models fit the genetic and biochemical data available so far.     

Internal synchronization of the main 0.1-Hz rhythms in the autonomic control of the cardiovascular system

Synchronization parameters of 0.1-Hz rhythms isolated from the heart rate and the oscillations of the blood volume in microcirculatory vessels were studied in 12 healthy subjects and 32 patients with acute myocardial infarction. Recordings of the electrocardiogram and the pulsogram from the distal phalanx of the index finger, as well as mechanical recording of respiration with the body in a horizontal position, were performed. In patients with myocardial infarction, the recordings were performed during the first three to five days and the third week after the infarction. Synchronization was tested by plotting phase differences and calculating the total percentage of phase synchronization. Synchronization parameters of 0.1-Hz rhythms were high in healthy subjects. In patients with acute myocardial infarction, synchronization of 0.1-Hz rhythms was considerably poorer. The data obtained suggest that the studied 0.1-Hz rhythms are two independent oscillatory processes that are synchronized in healthy subjects. However, this interaction may be disturbed in cardiovascular pathologies, e.g., myocardial infarction.     

Functions of heat shock proteins in the system of adaptive immunity. Construction of vaccines

One of the most important aspects of heat shock proteins (HSP) functioning, namely their role in reactions of innate and adaptive immunity, was reviewed in the article. Mechanisms of involvement of HSP in processing and presentation of antigens to T-lymphocytes were described. Principles of construction of prophylactic and therapeutic vaccines on the basis of HSP were set out. Assessment of range of indications for their use and possible risks related with inductive action of vaccines on the development of immunopathologic processes was a specially discussed topic.