Comparative study of membranes of Streptococcus faecalis and Micrococcus lysodeikticus

A comparative study of ultrastructure and IR-spectroscopy of osmotic shock membranes from cells of glycolyzing (Streptococcus faecalis) and respiring (Micrococcus lysodeikticus) bacteria, was made. The S. faecalis and M. lysodeikticus membranes differ in their cross-section. Treatment of the preliminary washed membranes of S. faecalis and M. lysodeikticus with a low ionic strength solution removes 40% and 70% of their proteins respectively, decreases the membrane cross-section but does not change their fracture faces. Pre-cooling of the membrane suspensions within the temperature range of +5 degrees-10 degrees results in the appearance of large smooth areas on S. faecalis membrane fracture faces, but does not affect the ones of M. lysodeikticus membrane. Treatment of the washed suspensions with Triton X-100 results in the appearance of drastic changes of S. faecalis membrane fracture faces and does not change the fracture faces of M. lysodeikticus membranes; treatment by the detergent does not alter the IR-spectroscopy of membranes of both bacteria. Treatment of S. faecalis and M. lysodeikticus membranes with high temperature irreversibly changes the structure of 20% and 40% of protein components respectively,, but does not affect the distribution of the subparticles on their fracture faces. It is assumed that the differences found are determined by the composition of lipid components of the membranes studied and that the amount of proteins closely bound with lipids in the membranes of S. faecalis is likely to be greater than that of M. lysodeikticus membranes.     

Delayed hypersensitivity in the chronic cholera vibrio carrier state in animals with an absence of normal microflora

The development of allergy in germ-free rats in chronic vibriocarriership was studied. The formation of specific delayed type hypersensitivity was found to occur to a limited extent in the animals devoid of normal microflora. The picture of hyperergic inflammation was revealed in the lymph nodes of vibriocarrier rats, the test for specific allergen being positive.     

Supercoiled DNA repair in thymocyte fractions differing in radiosensitivity

Mouse thymocyte fractions were isolated on the basis of buoyant density in a step-gradient of human serum albumin. These fractions were characterized by cell size, radiosensitivity and hydrocortisone sensitivity, and by labelled precursor incorporation into DNA, RNA and proteins. The relative sedimentation of nucleoids in sucrose gradient was also determined. Large and more radioresistant thymocytes were characterized by an increased rate of DNA repair compared with the fraction of radiosensitive small lymphocytes. Nucleoids prepared from the small thymocyte fraction had greater relative sedimentation rates than those derived from large cells. The response of relative sedimentation of nucleoids from large and small thymocyte fractions to ethidium bromide concentration does not permit a conclusion on different superhelix density for DNA in cells of these fractions. At the same time the estimate of the supercoiled domain size for nucleoids of large and small thymocyte fractions showed that in the more radiosensitive small cells domains of greater size were predominant.     

ENHANCED MULTIOBJECTIVE OPTIMIZATION TECHNIQUE FOR MULTIDISCIPLINARY DESIGN

An enhanced multiobjective formulation technique, capable of emphasizing specific objective functions during the optimization process, has been demonstrated on a complex multidisciplinary design application. The Kreisselmeier - Steinhauser (K-S) function approach, which has been used successfully in a variety of multiobjective optimization problems, has been modified using weight factors which enables the designer to emphasize specific design objectives during the optimization process. The technique has been implemented in two distinctively different problems. The first is a classical three bar truss problem and the second is a high-speed aircraft (a doubly swept wing-body configuration) application in which the multiobjective optimization procedure simultaneously minimizes the sonic boom and the drag-to-lift ratio (C_D/C_L) of the aircraft while maintaining the lift coefficient within prescribed limits. The results are compared with those of an equally weighted K-S multiobjective optimization. Results demonstrate the effectiveness of the enhanced multiobjective optimization procedure.