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The oxygen uptake and dehydrogenase activity of avirulent xyl+ and xyl- str hybrids (KCP-), obtained from virulent strains Sh. flexneri (Sh. flexneri 222 5 a and Sh. flexneri M42-432a) and donor strain E. coli AB 313, devoid of ability for intracellular multiplication in epithelial cells are studied. Some tricarboxylic acid intermediates, hexoses and pentoses were used as substrates. A definite tendency has been established, indicating a decreased rate of oxygen consumption and dehydrogenase activity of the hybrids, compared to the respiratory activity of the virulent recipient strains tsh. flexneri in all substrates used.

The glycolysis (aerobic and in the presence of KCN) of avirulent xyl+ and xyl-str hybrids Sh. flexneri x E. coli, devoid of their ability to multiply intracellularly in the epithelial cells, is studied. It is established that their glycolytic activity is considerably higher than the activity of the donor strain E. coli, and deviate significantly compared with shown activity of the virulent recipient strains Sh. flexneri. Xyl-str hybrids are showing high values of glycolysis in aerobic conditions and in the presence of KCN, while in xyl+ hybrids very active glycolysis is observed only in the presence of KCN - probably completely sufficient for the persistence of bacteria in the host-cell at anaerobic conditions.

The aerobic and anaerobic (in presence of KCN) glycolysis is studied of avirulent hybrids of Shigella flexneri according to the keratoconjunctivitis test of Sereny with genetic characteristics lac-+kcp-minus devoid of penetration ability. It is established that lac-+kcp-minus hybrids which have lost their ability to penetrate the cells due to replacement of KCP-gene of the chromosome of donor strain E. coli K-12 P4 times, are characterized with a steep decrease of their glycolitic activity in both aerobic and anaerobic conditions. The data shows that the loss of penetrate ability of the Shigella flexneri hybrids correlates with the decrease of their glycolitic ability.

Further investigations on the effect of different stress factors on the stability of intracellular membranes were carried out. Large granule fractions derived from livers of sleep-deprived and dehydrated rats and subjected to preincubation at 37 degrees and pH 5 were shown to release latent acid phosphatase with a delayed rate indicating an increased lysosomal stability towards acid media conditioning. Lysosomes of such animals, however, were found to be more sensitive to mechanical treatments (homogenization procedure in this case) than that of controls, a conclusion made on the basis of enhanced "free" and nonsedimentable phosphatase activities in liver homogenates. The stress factors which previously were included in the group of modifiers of the activity of the endoplasmic reticulum-located enzymes caused some changes in the action of certain chemicals on membranes. Earlier such changes were elicited for carbon tetrachloride and only on low-temperature-conditioned rats for chlorpromazine. The present results show that stress factors studied result in deviations (different in extent and in direction) from the usual effects of chlorpromazine, 2,4-dinitrophenol, phenobarbital and DDT on liver lysosomes and peroxisomes.

The catalase and phosphatase activity of avirulent by keratoconjunctival test of guinea pigs lac+, kcp- hybrids that have lost their ability of penetrating in the epithelium, received from virulent strains Shigella flexneri (Sh. flexneri 222 5a and Sh. flexneri M42-43) and donor strains Escherichia coli (E. coli K-12, P4x and E. coli H) was investigated. It was established that there is no any dependence between the lost of virulence of the hybrids and the level of the catalase activity. During the study of the phosphatase activity it was established, that in comparison with the recipient virulent shigella strains, the investigated avirulent lac+-hybrids revealed higher values of the enzyme activity.