[Characterization of the intestinal digestive glycosidases in plankton- and benthos-feeding species of the fish genus Ballerus (Cyprinidae)].

The activity of hydrolases (maltase, saccharase, amylolytic activity) in the intestinal mucosa of the plankton-feeding zope Ballerus ballerus and the benthos-feeding white-eye bream Ballerus sapa was investigated. The temperature characteristics of maltase hydrolysis (T(opt) and E(act)) are similar in both species. The lower K(m) of maltase hydrolysis in the white-eye bream reflects a higher enzyme/substrate affinity and indicates a more effective carbohydrate hydrolysis in the benthos-versus plankton-feeding species. The glycosidase activity in the white-eye bream is twice as high as in the zope. This may be due not only to different feeding spectra and biochemical food contents but also to the differences in thyroid status of species under consideration.

[The application of an impulse plasma jet for trauma of the liver]. / Primenenie impul'snoi plazmennoi strui pri travme pecheni.

The authors made an analysis of the application of a plasma jet with the help of an apparatus of original construction used for treatment of wounds of the liver in 36 patients. This apparatus has a number of advantages as compared with others. The plasma jet gives a reliable homostasis and minimum heat injuries to the liver tissues.

[Express method of determining blood in the abdominal cavity in closed abdominal injuries]. / Ekspress-metod opredeleniia krovi v briushnoi polosti pri zakrytoi travme zhivota.

The article describes an express-method of determining intraabdominal bleeding with the help of a benzidine test based on the ability of the hemine group of hemoglobin to catalyze the reaction of benzidine oxidation with hydrogen peroxide.

[Catheterization of the subclavian vein in patients with combined trauma in emergency situations]. / Kateterizatsiia podkliuchichnoi veny u bol'nykh s sochetannoi travmoi v ékstrennykh situatsiiakh.

The authors describe a simplified method of catheterization of the subclavian vein available in all medical institutions and in any situation.

[Prevalence of IS285 and IS100 in Yersinia pestis and Yersinia pseudotuberculosis genomes]. / Rasprostranennost' IS285 i IS100 v genomakh Yersinia pestis i Yersinia pseudotuberculosis.

Cell DNAs of various species of Enterobacteriaceae were hybridized with the probes based on IS285 and IS100, mobile genetic elements of Yersinia pestis. These IS elements are found only in the genomes of all tested Y. pestis strains and a number of strains of a related bacterium Y. pseudotuberculosis. Phylogenetic relations between the tested strains and correlation of fingerprints with the geographical origin of the strains were revealed by analysis of the hybridization profiles of Y. pestis and Y. pseudotuberculosis chromosomal DNAs with IS probes. Comparison of the chromosomal IS100 profiles of Y. pestis wild strain and its nonpigmented mutant helped us determine the minimal extension of the genetic rearrangement and detect at least three copies of the IS element in the mutant region.

[Plasmid composition of Yersinia pestis strains from different natural foci]. / Izuchenie plazmidnogo sostava shtammov vozbuditelia chumy iz raznykh prirodnykh ochagov.

The study of the plasmid composition of 246 Y. pestis strains from different natural foci in the USSR and other countries revealed that 173 strains (70%) carried three known plasmids with a molecular weight of about 6, 45-50 and 60 megadaltons (MD) respectively. In 20 strains (8%) obtained from different sources additional cryptic plasmids were detected. In some cases the absence of one or two typical plasmids was observed. Replicon pPst was shown to have quite constant molecular weight (6 MD), whereas plasmids pCad and especially pFra exhibited certain variations of their molecular weight (45-49 MD and 60-149 MD respectively) in strains of different origin.

[Plasmid heterogeneity in populations of Yersinia pestis strains]. / Geterogennost' populiatsii shtammov vozbuditelia chumy po plazmidnomu sostavu.

Yersinia pestis strains with the typical plasmid patterns were shown to have the heterogenic populations. Heterogeneity is increased by cultivation passages in artificial nutrient media and is manifested in plasmid elimination within several clones, plasmid integration into the chromosome, appearance of auxiliary plasmids or the ones with increased molecular masses. Passages of strains in experimental animals result in populations homogeneity with the typical plasmid patterns within all clones tested. The clones having changed the plasmid content and selected from heterogenic populations pertain their properties when cultivated in nutrient media and passaged in experimental animals.

The difference in the lcrV sequences between Y. pestis and Y. pseudotuberculosis and its application for characterization of Y. pseudotuberculosis strains.

We have sequenced the lcrGVH operon from Y. pseudotuberculosis plasmid pYV995 and compared its sequence with that of Y. pestis. The sequences were highly homological, however, six base pair substitutions were found in one short 14 bp region termed variable sequence. Two oligonucleotides corresponding to variable sequence of Y. pestis (pes-V) or Y. pseudotuberculosis (ptb-V) were synthesized and were used as molecular probes in hybridization experiments with sets of Y. pestis and Y. pseudotuberculosis strains. All 17 Y. pestis strains tested were positive only with the pes-V probe, 18 of 21 Y. pseudotuberculosis strains were positive with the ptb-V probe, while three Y. pseudotuberculosis strains reacted with the pes-V probe but not the ptb-V probe. The 200 bp fragment including variable sequence was sequenced in seven Y. pseudotuberculosis strains. The Y. pseudotuberculosis strains which were positive with the pes-V probe possessed the 200 bp fragment sequence almost identical with that from Y. pestis. No correlation between the Y. pestis-like lcrV sequence and virulence was found for these strains. Moreover, the Y. pseudotuberculosis strains with Y. pestis-like sequences in contrast to Y. pestis possessed unaltered yadA gene. However, we have found the yadA frameshift mutation characteristic for Y. pestis in one Y. pseudotuberculosis strain 312.

Analysis of Yersinia pestis chromosomal determinants Pgm+ and Psts associated with virulence.

The ability to absorb exogenous pigments (Pgm+) has, until now, been considered an established virulence factor of Yersinia pestis, the causative agent of plague. This property correlates with the sensitivity to the bacteriocin pesticin (Psts). Both functions are chromosomally encoded. In the present study, using Hfr donors and isogenic Pgm-Psts and Pgm-Pstr mutants, these functions were shown to be determined by discrete but closely linked genes. These markers designated pgm and psn, respectively, were preliminarily located within a linkage group including 11 loci. It was also found that pigmentation is not essential for mouse virulence but is necessary for survival of Y. pestis in the flea, the plague vector. At the same time, conversion of an avirulent Pstr mutant to pesticin sensitivity restored some degree of virulence.

Integration of the plasmid encoding the synthesis of capsular antigen and murine toxin into Yersinia pestis chromosome.

Yersinia pestis, the causative agent of plague, usually carries three plasmids. The largest of them, a 60 megadalton (MDa) replicon designated pFra determines the synthesis of capsular antigen (fraction I) and murine toxin. Both products are involved in the expression of virulence. Previously, several cases of integration into the bacterial chromosome of the calcium dependence plasmid common to pathogenic Yersinia species have been described. In this study, using the Southern hybridization method, we have shown that the plasmid pFra of Y. pestis also integrates into the host chromosome in some clones of strain populations. The integration could be observed for both the intact plasmid and its mutant derivatives unable to express murine toxin or mediating a dramatically reduced level of capsular antigen synthesis.

[Experience in the use of Soviet-made disk prostheses EMIKS and LIKS]. / Opyt primeneniia otechestvennykh diskovykh protezov EMIKS i LIKS.

Experience in the application of and disc prostheses in 614 patients in generalized. Mitral prosthetics was conducted in 256, aortic in 229, and mitral++-aortic in 129 patients. Hospital lethality was, respectively, 3.9, 4.8, and 8.5%. In postoperative follow-up periods of up to 7 years 92.1% of patients were examined. Survival was 88.1 +/- 0.71% in the mitral, 87.0 +/- 0.62% in the aortic, and 80.2 +/- 0.84% in the mitral-aortic group. No thromboembolic complications occurred in 88.7 +/- 0.64%, 96.9 +/- 0.31%, and 88.3 +/- 0.68% of patients, respectively. In the mitral position the mid-diastolic gradient was 4.0 +/- 0.31 mm Hg on the prosthesis and 3.8 +/- 0.82 mm Hg on the prosthesis; in the aortic position the peak systolic gradient was, respectively, 23.2 +/- 0.58 and 22.4 +/- 0.7 mm Hg. At the time of examination 97% of patients belonged to I and II functional classes.

[Cloning of the locus encoding synthesis of an outer membrane protein (Omp2) of the calcium dependence plasmid of Yersinia pestis (Lehmann, Neumann)]. / Klonirovanie lokusa plazmidy kal'tsiizavisimosti Yersinia pestis (Lehmann, Neumann), kodiruiushchego sintez belka vneshnei membranyi (BVM2)

The genetic locus of Yersinia pestis encoding synthesis of a 46-kDa heat-inducible outer membrane protein (Omp2) was cloned into pBR322 plasmid. The Omp2 was shown to be analogous to previously described YopH and Yop2b proteins. The fifth HindIII fragment of 48-MDa calcium dependence plasmid pCad358 mediates production of 31- and 28-kDa proteins, irrespective of orientation of the insertion. A 31-kDa polypeptide seems to correspond to the YopJ described elsewhere. The maps of BamHI and HindIII of pCad358 region studied differed from those described for pCD1 plasmid of Y. pestis KIM. The products encoded by genes from the fragment cloned in the Pgm+ background give rise to considerable growth of Y. pestis within mouse peritoneal macrophages but were not sufficient to cause lethal infectious process.

[The role of IS-elements of Yersinia pestis (Lehmann, Neumann) in the emergence of calcium-independent mutations]. / Rol' IS-élementov Yersinia pestis (Lehmann, Neumann) v vozniknovenii mutatsii kal'tsiinezavisimosti.

Calcium independent mutants of two Yersinia pestis strains were studied. Insertions of IS100 element at three different sites of plasmid pCad within calcium dependence region were detected in Y. pestis EV, as well as two extensive deletions covering the whole region. It was shown that IS100 carries no HindIII sites. Novel IS element of Y. pestis designated IS101 was discovered in strain 358, in addition to IS100. It is distinguished by a slightly smaller size, HindIII site presence and high specificity of integration.

Plasmid content in Yersinia pestis strains of different origin.

Plasmid content in 242 Yersinia pestis strains from various natural plague foci of the U.S.S.R. and other countries was studied. Of these strains, 172 (71%) were shown to carry three plasmids described previously of about 6, 45-50 and 60 MDa, respectively. Twenty strains (8%) from different foci harboured additional cryptic plasmids, most often of about 20 mDa in size. Plasmid pPst displayed considerable constancy of its molecular mass. On the contrary, size variations of pCad (45-49 MDa) and, especially, pFra (60-190 MDa) were found. Molecular mass of these plasmids correlated with the host strain origin.

[Genetic analysis and simulation of the virulence of Yersinia pestis]. / Geneticheskii analiz i modelirovanie virulentnosti Yersinia pestis.

The genetic analysis of Y. pestis virulence factors accomplished in the 358 strain isogenic system allowed us to determine a minimal set of known factors providing pathogenicity. The combination of chromosomal marker Pgm+ and calcium dependence plasmid (pCad) is shown to be sufficient for preserving the virulence of Y. pestis. Experimental modelling of virulence in this microorganism by the genetic exchange methods was carried out. The reduced virulence of the strains Pgm+ and pCad+ for guinea pigs was detected.

[Incompatibility of the Cad plasmid from Yersinia pestis with plasmids of the IncFI group]. / Nesovmestimost' plazmidy pCad chumnogo mikroba s plazmidami gruppy IncFI.

The relation of Yersinia pestis calcium dependence plasmid (pCad) to known Inc FI (F'lac, R386, pOX38) and IncFV (F0lac) plasmids has been studied. Evidence that plasmid pCad of Yersinia pestis belongs to FI incompatibility group is presented.