Plasmid analysis of cadmium- and penicillin-resistant strains of staphylococci isolated in maternity hospitals]

The plasmid analysis of a collection of the staphylococci isolated was made in the obstetric hospitals of Nizhny Novgorod and Arzamas in 1986-1989. It revealed the presence of large complex plasmids with a molecular weight of 22 MD carrying the determinants of resistance to penicillins and cadmium and mercury ions in polyresistant strains. Conjugation transfer of the plasmid even between the staphylococci of different species was performed under experimental conditions. It was suggested that occurrence of the strains carrying the complex cadmium-penicillinase plasmid was due to violation of the sanitary or ecological requirements.     

The epidemic situation in relation to HIV infection in the Volga River region

1,036 HIV-infected persons were detected in the area by March 1, 1998; of these, 552 persons were detected in Nizhny Novgorod Province and 364 persons in Saratov Province. For all that at different periods 150 HIV-infected detainees were kept in the pretrial detention prisons of Nizhny Novgorod Province and 60 HIV-infected detainees, in the pretrial detention prisons of Saratov Province. Some measures permitting the prevention of further increase in the occurrence of HIV infection in the region are proposed.     

Mitochondrial Heteroplasmy in Marsh Frog (Pelophylax ridibundus Pallas, 1771)

Russian Journal of Genetics - The population features of nuclear and mitochondrial genomes of P. ridibundus Pallas, 1771 and related species of green frogs from Nizhny Novgorod and Sverdlovsk...     

New experience in informational and educational work

During the World Day of AIDS Control (December 1, 1999) the global action "General Class Hour" was conducted in Nizhny Novgorod in all general-education and specialized secondary schools, colleges and professional schools. 197,600 students of 169 general-education schools and 28 specialized schools, as well as 6,200 teachers and 300 volunteers conducting "General Class Hour", took part in the action.     

HIV infection in children perinatally infected

During the period from 1987 to the middle of 1996 only 20 children were born of HIV-infected women, while during the following 1.5 years the number of such children were 59, the maximum number of seropositive children being registered in Kaliningrad and the Kaliningrad region, in the Krasnodar Territory, Stavropol and Nizhny Novgorod (altogether 46 children). Out of 79 children born of HIV-infected mothers during the whole period of the epidemic, 8 children died. Out of the children born before 1995 who remained alive, 9 children were struck off the register after 3 years of observation due to the absence of HIV infection. By the end of 1997 63 children were registered, the majority of them born in 1996-1997.     

Activity of restriction endonuclease Sso II in Escherichia coli strains transformed by Shigella sonnei 47 plasmids

The inverse dependence of activity of restriction endonuclease SsoII preparations on the number of low molecular mass plasmids of Shigella sonnei transforming Escherichia coli recipient cells producing the enzyme has been shown. Escherichia coli strain producing efficiently one of two Shigella sonnei 47 restriction endonucleases SsoII has been isolated. The producer strain harbours two of the nine Shigella sonnei 47 plasmids. One of them P4 codes for SsoII+ phenotype while the other P9 determines the plasmids conjugation transfer. Biochemical and physiological characteristics of the producer strain XS13 are identical to the ones of the recipient Escherichia coli strain PS200. XS13 is unable to induce keratoconjunctivitis in guinea pigs in pathogenicity test.     

Ecologocenotical characteristics of the herbaceous cover along the highways of Nizhny Novgorod

A total of 86 species of vascular plants have been found in the studied territories along the highways of Nizhny Novgorod. Asteraceae, Poaceae, and Fabaceae play a great role in the taxonomic structure of herbs. Cyperaceae and Rosaceae are less important. Among the ecologocenotical groups, meadow species form the basis of the herbaceous cover, but their participation diminishes at distances of 1–3 m from the highways. Herbaceous plants include also flowering meadow species, which play an indispensable aesthetic role.     

Gene pool structure of Russian populations from the European part of Russia inferred from the data on Y chromosome haplogroups distribution

Population structure of Russian population from the European part of Russia was investigated by analyzing the distribution of 23 SNP makers of Y chromosome in Russian populations from Kaluga oblast, Yaroslavl' oblast, Vladimir oblast, Nizhny Novgorod oblast, Pskov oblast, Tula oblast, Belgorod oblast, and Novgorod oblast. In the populations studied a total of 14 Y-chromosome haplogroups (E, F*, I, J, K*, N3a, N2, P*, R1*, R1a1, C3, H, and A) were discovered, of which haplogroups R1a1, I, and N3a were the prevailing. Analysis of Phi statistics in the populations grouped in accordance to the dialect subdivision of the Russian language, showed the absence of statistically significant differences between Russian population groups. Analysis of the Y-chromosome markers distribution patterns among Russian population (10 population groups) in comparison with the population of Germany (11 population groups) revealed statistically significant differences between the gene pools of Slavs (Russians and Poles) and Teutons (Germans).     

Use of endogenous host plasmids for generation of Escherichia coli O157:H7 and Shigella sonnei strains that stably express the green fluorescent protein

The gfp gene was manipulated from a commercially available, high copy vector into endogenous plasmids of Escherichia coli O157:H7 and Shigella sonnei to yield stable GFP strains that required neither high copy number for visualization nor antibiotics for stable maintenance of the phenotype. The GFP phenotype of these strains remained stable after repeated passages in media and conditions that enhance plasmid instability and loss from bacterial cells. These results demonstrate the utility of the endogenous plasmids in selectively marking bacteria without altering host cellular function or biochemical properties.     

Thermosensitive H1 plasmids determining citrate utilization.

Twelve thermosensitive H1 plasmids from strains of Salmonella typhi that had caused outbreaks of chloramphenicol-resistant typhoid fever in Vietnam, Thailand and India mediated citrate utilization (Cit+) in a prototrophic Escherichia coli K12 strain but not in the S. typhi strains from which they were derived. Four H1 plasmids from a similar outbreak in Mexico differed from the Far Eastern plasmids in not mediating citrate utlization but in mediating mercury resistance. H1 plasmids resembling the Far Eastern and the Mexican plasmids in regard to citrate utilization and mercury resistance were found in sewage in Britain. Citrate utilization was transferred to eight pathogenic strains of E. coli and to one strain each of Shigella flexneri and Shigella sonnei. Cultures of Cit+ bacteria grew more rapidly in citrate media at 28 degrees C than at 37 degrees C. Plasmid mutants that were more efficient at utilizing citrate were present in all such cultures--they grew equally well or better at 37 degrees C than at 28 degrees C. None of 222 strains of E. coli or Shigella that contained a variety of different plasmids were able to utilize citrate. This property was not transferred to the prototrophic E. coli K12 strain from Citrobacter (3 strains), Salmonella (39 strains), Proteus (44 strains), Klebsiella pneumoniae (33 strains) or Pseudomonas aeruginosa (44 strains).     

驱除痢疾杆菌侵袭大质粒的新方法

用质粒不相容性原理驱除痢疾杆菌福氏 2a 2 4 5 7T和宋内S7的侵袭大质粒 ,先从福氏2a侵袭大质粒分别扩增ori和inc基因 ,将它们克隆至 pMD18 T载体 ,得重组质粒pMDori和 pMDinc ,然后转化 2 4 5 7T和S7,不管是pMDori还是 pMDinc都能竞争驱除痢疾杆菌福氏 2a 2 4 5 7T和宋内S7的侵袭大质粒。     

Polymorphism of the mtDNA Control Region in Reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>) from the Mainland of the Northeastern Part of European Russia

Based on an analysis of the polymorphism of nucleotide sequences (n = 103) of the hypervariable fragment of the mtDNA control region (D-loop), the genetic diversity of wild and domestic reindeer from the mainland of the European Northeast of Russia (eastern parts of Arkhangelsk oblast, Komi Republic, and the Nenets Autonomous Okrug) was studied. Relatively high values of genetic diversity indices were detected. Phylogenetic analysis showed close relationships between reindeer of the study region and those of the tundra zone of Siberia. The influence of domestic reindeer on the formation of the genetic diversity of the wild reindeer was considered as negligible. Genetic lines belonging to an extinct group of forest reindeer from the Nizhny Novgorod region were found among the modern groups of reindeer from the European Northeast of Russia.     

Study of hydrocarbon oxidizing microorganisms from deep groundwater of the Puchezh-Katunki impact structure

The presence of viable hydrocarbon-oxidizing microorganisms has been shown in the under-ground waters exposed by the Vorotilovskaya deep well (the Puchezh-Katunki astrobleme, 75 km north of Nizhny Novgorod, 1900- and 3200-m deep) using the method of chromatography-mass spectrometry of specific biomarkers of the microbial cell wall and the classical methods of bacteriology. Several microbial species have been isolated in pure culture and identified. Two bacillary species, Bacillus pumilus KTB-2 and Bacillus subtilis KTB-4, were maintained in pure cultures at reinoculations. The effects of mineralization and aeration of the medium on the growth characteristics of Bacillus pumilus KTB-2 in batch culture have been studied.     

Characterization of plasmids from antibiotic-resistant Shigella isolates by agarose gell electrophoresis.

Gel electrophoresis of DNA from 95 clinical isolates of Shigella sonnei and Shigella flexneri resistant to antibiotics revealed a heterogeneous plasmid population. Most of the plasmids were smaller than 6 megadaltons (Mdal). Six S. sonnei isolates with the most common antibiotic resistance pattern were characterized. They had two plasmids in common: one was a self-transmissible Fi+ plasmid of 46 Mdal encoding resistance to streptomycin and sulphafurazole. In addition, several cryptic plasmids ranging in size from 1.0 to 24.5 Mdal were present. Mobilization of the 5.5 Mdal SuSm plasmid and a 1.0 Mdal cryptic plasmid was demonstrated with all six S. sonnei isolates during conjugation. This mobilization was mediated by the 46 Mdal self-transmissible Fi+ R plasmid and also by a 24.5 Mdal Fi- plasmid carrying no known drug resistance determinants.     

Conjugal transferability of multiple resistance in Shigella strains

Shigella strains isolated in Japan between 1971 and 1979 were surveyed for drug resistance and distribution of R plasmids. Of 2,510 strains, 89.3% were resistant to either one or various combinations of four drugs, tetracycline, chloramphenicol, streptomycin, and sulfanilamide. About 66% of the Shigella isolates were quadruply resistant. The frequency of isolation of R plasmids from quadruply resistant Shigella strains was the highest when compared with other strains resistant to various combinations of the four drugs. The conjugal transferability of 204 quadruply resistant strains isolated between 1977 and 1979 was tested by various mixed-culture methods. Among the total strains examined, 70.6% carried transferable resistance when tested by the conventional broth culture method, 90.2% transferred their resistance when, in addition the replica-plating method was used and 97.5% could transfer their resistance when the membrane filter method was also used. Although the remaining five strains could not transfer their resistance by any of the mixed culture methods, the drug resistance of four of the five strains was mobilized by the concomitant presence of F-tet or T-kan plasmid. These results indicate that almost all of the quadruple resistance in Shigella isolates was mediated by plasmid.     

The cyclicity and prognosis of shigellosis morbidity in Russia

The epidemic process (EP) of shigellosis morbidity proceeds in cycles. As shown in this study, cyclic curves are the sum of polyharmonic fluctuations, being the axis of EP. The duration of one cycle is 18 years, and its configuration is stably retained for a long time. In Nizhny Novgorod shigellosis morbidity is strongly correlated with air temperature is summer at the peak of cyclic rises and moderately correlated in the years of low morbidity. In some cities of the Russian Federation fluctuations of air temperature have been found of occur synchronously with disturbances of the magnetic field of the earth. The character and stability of EP cycles provide grounds for the prognostication of shigellosis morbidity. The current cycle will end in the year 2000, and then natural preconditions for a new cyclic rise will appear.     

Change in responses of skin receptors to repeated heat stimulation

In experiments with cats, study was made of the period of increase in afferent activity during repeated heat stimulation (up to 48°C) of the skin; parallel recordings were made of skin tonus. With each application of heat, skin tonus decreased. Meanwhile, when skin temperature approached normal (30°), the skin again contracted, but tonus was not completely restored with subsequent heating (3 min pause). Repeated heating resulted in loss of tonus. At the same time, the period in which afferent activity developed decreased. These two processes are parallel, which leads to the conclusion that they are related.Laboratory for the Study of Excitable Structures, Institute of Applied Physics, Russian Academy of Sciences. Nizhny Novgorod State Medical Institute. Translated from Neirofiziologiya, Vol. 24, No. 5, pp. 577–582, September–October, 1992.     

The stability of O-antigen plasmid is determined by a chromosomal region of Shigella dysenteriae 1

It is well established that plasmids are involved in the expression of lipopolysaccharide in certain species of Shigella. In Shigella sonnei, both the biosynthesis of oligosaccharide side chains (O antigen), and cell invasiveness are controlled exclusively by a 120 megadalton (MDa) plasmid. In Shigella dysenteriae 1, a 10 kilobase (kb) plasmid is required for O-antigen production. Shigella dysenteriae 1 strains devoid of this plasmid lose the ability to synthesize O antigen. Interestingly, this 10-kb plasmid is not stably maintained in Escherichia coli K-12 strains, where it is lost spontaneously at a high frequency. Our genetic analyses of Shigella dysenteriae 1 strain IDBM11 and its derivatives indicate that the stability of this plasmid is associated with the histidine region of the chromosome which is unique to Shigella dysenteriae. Furthermore, the 10-kb plasmid is stably maintained in wild-type IDBM11 with an intact histidine locus. However, this plasmid is not stable in IDBM11 derivatives (e.g., IDBM11-1 and IDBM11-2), in which the his locus has been substituted with the histidine region of an E. coli K-12 chromosome. The S. dysenteriae IDBM11 strain, and its derivatives (lacking a 10-kb plasmid), displayed an invasive property as demonstrated by their internalization by HeLa cells in an in vitro assay. Thus the 10-kb plasmid of Shigella dysenteriae 1 is required for O-antigen synthesis but not for cell invasion.     

Excitation of cat spinal cord dorsal column fibers during stimulation of different fiber groups of cutaneous and somatic nerves

The effects of electrically stimulating different groups of nerve fibers supplying the skin and muscle on evoked potentials in cat spinal cord dorsal columns were studied. Significant differences in the configuration of dorsal column potentials recorded in response to stimulation of these nerves were found. It was shown that cutaneous nerve unmyelinated fibres were connected to unmyelinated dorsal column fibers. In addition, excitation of cutaneous C-fibers lead to activation of dorsal column fibers with the maximum conduction velocity. The somatic nerve was only connected to myelinated dorsal column fibers, and excitation of its non-myelinated fibers did not cause other types of dorsal column fibers to be activated. It is suggested that the acceleration of cutaneous signal transmission in the dorsal column system may be brought about by the necessity for rapid warning of potentially harmful stimuli.Medical Institute, Russian Federation Ministry of Public Health, Nizhny Novgorod. Translated from Neirofiziologiya, Vol. 24, No. 5, pp. 625–635, September–October, 1992.     

Distribution of insertion sequence IS1 in multiple-antibiotic resistant clinical Enterobacteriaceae strains

The presence of insertion sequence IS1 in 70 multiple-antibiotic resistant clinical strains was determined. This 70-strain collection comprised 46 Escherichia coli, 18 Salmonella and 6 Shigella strains. The presence of IS1 was detected in the chromosome and plasmids of 73% and 63% of the strains, respectively, and 51% of the strains carried IS1 in both. The frequency of IS1 was higher in Salmonella than in E. coli and Shigella strains. A total of 31 strains carried large plasmids with IS1; 10 of these strains (32.3%) were able to transfer all or some of the antibiotic resistance markers to E. coli K12 or S. typhimurium recipient strains. Resistance markers of all clinical strains were maintained stably after several generations of growth. The presence of IS1 in a relatively high percentage of plasmids of multiple-antibiotic resistant clinical isolates, suggests a role for this sequence in the dissemination of genes which code for antibiotic resistance.