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2.
Nat Commun ; 10(1): 4103, 2019 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-31488829

RESUMEN

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

3.
Nat Commun ; 10(1): 3121, 2019 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-31311923

RESUMEN

Increasing the potential of soil to store carbon (C) is an acknowledged and emphasized strategy for capturing atmospheric CO2. Well-recognized approaches for soil C accretion include reducing soil disturbance, increasing plant biomass inputs, and enhancing plant diversity. Yet experimental evidence often fails to support anticipated C gains, suggesting that our integrated understanding of soil C accretion remains insufficient. Here we use a unique combination of X-ray micro-tomography and micro-scale enzyme mapping to demonstrate for the first time that plant-stimulated soil pore formation appears to be a major, hitherto unrecognized, determinant of whether new C inputs are stored or lost to the atmosphere. Unlike monocultures, diverse plant communities favor the development of 30-150 µm pores. Such pores are the micro-environments associated with higher enzyme activities, and greater abundance of such pores translates into a greater spatial footprint that microorganisms make on the soil and consequently soil C storage capacity.


Asunto(s)
Biomasa , Ciclo del Carbono , Microbiota/fisiología , Microbiología del Suelo , Atmósfera/química , Biodiversidad , Carbono/metabolismo , Dióxido de Carbono/metabolismo , Raíces de Plantas , Plantas , Suelo/química
4.
Genetika ; 52(3): 311-9, 2016 Mar.
Artículo en Ruso | MEDLINE | ID: mdl-27281851

RESUMEN

The variability of 21 allozyme and three microsatellite loci of chloroplast DNA (cpDNA) was studied in the populations of Siberian spruce (Picea obovata Ledeb.) from Irkutsk oblast, Magadan oblast, Buryatia, and Mongolia. It was demonstrated that the highest level of genetic diversity among the examined populations at both allozyme and microsatellite loci was observed in the Tulyushka population from Irkutsk oblast. The lowest level of genetic diversity was observed in marginal isolated populations of Bogd Uul and Magadan. In the relict spruce population from Olkhon Island, differing from the other populations in the lowest allelic diversity of both types of markers, no expected decline of expected heterozygosity and haplotype diversity was observed. In this population, the variability parameters mentioned were close to the population mean. The obtained intrapopulation and intraspecific variability parameters of allozyme and microsatellite loci of chloroplast DNA and the data on the population differentiation at these loci indicate that the given markers can be used for the analysis of the population structure of Siberian spruce.


Asunto(s)
Genoma del Cloroplasto , Repeticiones de Microsatélite , Picea/genética , Polimorfismo Genético , Isoenzimas/genética , Siberia
5.
Genetika ; 52(9): 1042-54, 2016 Sep.
Artículo en Ruso | MEDLINE | ID: mdl-29369559

RESUMEN

We performed an analysis of linkage disequilibrium of alleles of 15 allozyme loci in 35 populations of Scots pine in the Siberian part of the range between 50° and 56° N and 79° and 107° E. We found a significant deviation in the distribution of genotypes of 1­9 pairs of loci in the investigated samples. We established correlations between frequencies of certain pairs of linked loci with ecological conditions and geographical coordinates of habitats of the pine populations. We present the results of comparative analysis of the differences in certain morphological features of trees with significantly predominant genotypes for pairs of linked loci in three isolated populations: in the south of Krasnoyarsk krai, Khakassia, and Tuva.


Asunto(s)
Sitios Genéticos , Genotipo , Desequilibrio de Ligamiento , Pinus sylvestris/genética , Isoenzimas/genética , Pinus sylvestris/enzimología , Siberia
6.
Genetika ; 52(11): 1262-9, 2016 Nov.
Artículo en Ruso | MEDLINE | ID: mdl-29372789

RESUMEN

The results of the study of 21 populations of Siberian spruce (Picea obovata Ledeb.) from different parts of the species natural range by microsatellite (SSR) analysis of nuclear DNA are presented. Using nine loci developed for Picea abies (L.) Karst. and Picea glauca (Moench) Voss and detecting variation in Picea obovata, the parameters of intra- and interpopulation genetic diversity, as well as the degree of population differentiation, were determined. It was demonstrated that the population of Siberian spruce in the study was characterized by a relatively high average level of intrapopulation variability (H o = 0.408; H e = 0.423) and low interpopulation differentiation (F st = 0.048, P = 0.001) at this class of DNA markers. The genetic distance between populations ranged from 0.009 to 0.167, averaging 0.039. The isolated Magadan population, located in the extreme Northeast of Russia at a considerable distance from the main species range and characterized by the lowest genetic diversity among the studied populations, was maximally differentiated from the rest of the spruce populations. In addition, the steppe Ubukun population from Buryatia and the population from the Bogd Khan Uul Biosphere Reserve, Mongolia, were considerably different in the genetic structure from most populations of Siberian spruce, although to a lesser extent than the Magadan population. These findings are consistent with the results of previous studies of this species carried out using allozyme and microsatellite loci of chloroplast DNA and point to the prospects of using nuclear microsatellites as DNA markers to analyze the population genetic structure of Siberian spruce.


Asunto(s)
Variación Genética , Repeticiones de Microsatélite , Picea/genética , Marcadores Genéticos , Picea/enzimología , Siberia
7.
Urologiia ; (5): 10-14, 2016 Nov.
Artículo en Ruso | MEDLINE | ID: mdl-28248013

RESUMEN

AIM: To investigate the mechanisms of individual platelet reactivity to ADP and adrenaline associated with the variability of hematuria after lithotripsy in patients with chronic obstructive pyelonephritis (COPN). MATERIALS AND METHODS: The study included 41 COPN patients admitted to the Department of Urology for lithotripsy (LT). The contact ultrasonic LT was performed using the Karl Storz Calcuson Ultrasonic Lithotripsy System. Postoperative hematuria was assessed by microscopic red blood cell count. Platelets were separated from the citrated peripheral blood by centrifugation. Platelet aggregation was measured by Chrono-log aggregometer using agonists (ADP, adrenaline) at a concentration of EC50 and EU10. RESULTS: There were three types of platelet functional response to ADP and adrenaline after LT (increased, unchanged and decreased aggregation), but the predominant type of individual response was increased platelet aggregation. Testing 24 hours after LT revealed 7 platelet phenotypes differing in functional activity of 2-adrenoceptor agonist and purine receptors (R2Y1 and R2Y12). Normal purine receptor activity was associated with the ability of platelets to respond to adrenaline by increasing the functional activity aimed at limiting hematuria. Reduced platelet response to ADP after LT reaching the level of hyporesponsiveness may be viewed as a predictor of severe hematuria after surgery. CONCLUSION: Individual platelet reactivity, manifested by the interaction of ADP and adrenaline agonist, determines the effectiveness of the increase in pro-aggregation capacity of platelets in developing postoperative hematuria.


Asunto(s)
Plaquetas/patología , Hematuria/sangre , Litotricia/efectos adversos , Adenosina Difosfato/agonistas , Plaquetas/efectos de los fármacos , Enfermedad Crónica , Epinefrina/farmacología , Hematuria/etiología , Hematuria/orina , Humanos , Agregación Plaquetaria/efectos de los fármacos , Pielonefritis/sangre , Pielonefritis/terapia , Pielonefritis/orina , Cálculos Urinarios/sangre , Cálculos Urinarios/terapia , Cálculos Urinarios/orina
8.
Klin Lab Diagn ; (6): 16-8, 2014 Jun.
Artículo en Ruso | MEDLINE | ID: mdl-25335395

RESUMEN

The leucocytosis and increase of numbers of neutrophils are two indicators commonly applied to evaluate acute inflammatory reaction. At that, the normality reference range is a standard of comparison. Considerably more often occurs the need to evaluate severity of patient condition or expression of inflammation determined by individual reactivity of organism. In this context the reaction of leukocytes was analyzed in 80 males of three age categories: younger than 55 years, 55-65 years and older than 65 years. All participants of study had verified diagnosis of chronic obstructive pyelonephritis. The comparison of leukopoiesis and erythrocyte sedimentation rate at the phase of remission and recurrence of chronic obstructive pyelonephritis of each age category made it possible to single out groups of patients with different reactivity of organism. In perspective, a possibility appears to individualize tactics of conservation therapy under chronic obstructive pyelonephritis and to evaluate its effectiveness.


Asunto(s)
Pielonefritis/sangre , Factores de Edad , Anciano , Sedimentación Sanguínea , Enfermedad Crónica , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad
9.
Adv Gerontol ; 27(3): 472-6, 2014.
Artículo en Ruso | MEDLINE | ID: mdl-25826994

RESUMEN

The aim of the study was to evaluate the adaptive changes of peripheral blood cells of recurrence inflammation in aged women with chronic obstructive pyelonephritis (COPN). An analysis of clinical and laboratory data was carried out on 50 women who were distributed into two age periods: under 55 years (the comparison group) and over 65 years. In women of 65+, during recurrence of COPN, the degree of leukocyte increase, neutrophils, monocytes and erythrocyte sedimentation rate (ESR) reached 90,1, 20,8, 71,4 and 31,6%, whereas lymphocyte count was less by 2,8 times in comparison with remission. In women under 55 years (in recurrence of COPN), degree of leukocyte increase was 87% (p<0,001), neutrophils--4, 8% (p<0,05), monocytes--in 2,04 times (p<0,001), ESR was less in 3,1 times (p<0,001) and lymphocyte count was less than 19,5% (p>0,05). The manifestation of neutrophilocytosis and lymphocytopenia might be due to age-related features of adaptive reaction in peripheral blood cells during the COPN recurrence.


Asunto(s)
Adaptación Fisiológica , Envejecimiento/sangre , Pielonefritis/sangre , Anciano , Enfermedad Crónica , Femenino , Humanos , Recuento de Leucocitos , Leucocitos/citología , Persona de Mediana Edad , Monocitos/citología , Neutrófilos/citología
10.
Bioorg Khim ; 38(5): 621-8, 2012.
Artículo en Ruso | MEDLINE | ID: mdl-23342496

RESUMEN

Neurotropic, neuroprotective and antioxidant actions of the enantiomers and the racemate of 2-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)-4-methylthiobutanoic acid were investigated. Only (+)-(S)-2-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)-4-methylthiobutanoic acid was found to have neuroprotective properties. A distereoselective synthesis of enantiomers and racemate was performed by condensations of (S), (R) and (R,S)-N-carbamoylmethionines with 4,5-dihydroxyimidazolidin-2-one (DHI), respectively. By the X-ray method, the major racemate was proved to crystallize from water as a conglomerate. No antioxidant activity was revealed.


Asunto(s)
Butiratos/química , Butiratos/síntesis química , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/síntesis química , Animales , Antioxidantes/síntesis química , Antioxidantes/química , Antioxidantes/farmacología , Butiratos/farmacología , Masculino , Ratones , Estructura Molecular , Fármacos Neuroprotectores/farmacología
11.
Genetika ; 44(1): 45-53, 2008 Jan.
Artículo en Ruso | MEDLINE | ID: mdl-18409386

RESUMEN

Based on the analysis of 22 loci controlling allozyme variation of MDH, SKDH, 6-PGD, IDH, PEPCA, GOT, FDH, LAP, PGI, PGM, SOD, and GDH, the data on within- and among-population variation for nine cenopopulations of Siberian spruce (Picea obovata Ledeb.) located along the Yenisei meridian, from 65 degrees 50' NL to 52degrees 14' NL, were obtained. It was demonstrated that 86.36% of the loci, tested in the species analyzed, were polymorphic. The mean number of alleles per locus was 2.91, and the observed and expected heterozygosity constituted 0.161 and 0.168, respectively. More than 97% of total variation occurred within the populations, while the proportion of the among-population variation constituted only 2.3% (Fst =0.0230). Genetic distance (DN) between the populations examined varied from 0.0019 to 0.0115, averaging at 0.0051. It was shown that in the part of the Siberian spruce range examined there was no close association between the level of the genetic differentiation of the populations and the geographic distance between them. It seems likely, that this finding can be associated with the fact that Siberian spruce, growing on this territory, is the intrazonal species, i.e., it is not attached to a certain forest zone, and its distribution is mostly determined by local ecological conditions.


Asunto(s)
ADN de Plantas/genética , Picea/genética , Polimorfismo Genético , Sitios de Carácter Cuantitativo/genética , Genética de Población , Picea/enzimología , Siberia
12.
J Environ Qual ; 33(4): 1535-44, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15254136

RESUMEN

Excessive fertilization with organic and/or inorganic P amendments to cropland increases the potential risk of P loss to surface waters. The objective of this study was to evaluate the effects of soil test P level, source, and application method of P amendments on P in runoff following soybean [Glycine max (L.) Merr.]. The treatments consisted of two rates of swine (Sus scrofa domestica) liquid manure surface-applied and injected, 54 kg P ha(-1) triple superphosphate (TSP) surface-applied and incorporated, and a control with and without chisel-plowing. Rainfall simulations were conducted one month (1MO) and six months (6MO) after P amendment application for 2 yr. Soil injection of swine manure compared with surface application resulted in runoff P concentration decreases of 93, 82, and 94%, and P load decreases of 99, 94, and 99% for dissolved reactive phosphorus (DRP), total phosphorus (TP), and algal-available phosphorus (AAP), respectively. Incorporation of TSP also reduced P concentration in runoff significantly. Runoff P concentration and load from incorporated amendments did not differ from the control. Factors most strongly related to P in runoff from the incorporated treatments included Bray P1 soil extraction value for DRP concentration, and Bray P1 and sediment content in runoff for AAP and TP concentration and load. Injecting manure and chisel-plowing inorganic fertilizer reduced runoff P losses, decreased runoff volumes, and increased the time to runoff, thus minimizing the potential risk of surface water contamination. After incorporating the P amendments, controlling erosion is the main target to minimize TP losses from agricultural soils.


Asunto(s)
Fertilizantes , Estiércol , Fósforo/análisis , Contaminantes del Suelo/análisis , Contaminantes del Agua/análisis , Animales , Conservación de los Recursos Naturales , Monitoreo del Ambiente , Lluvia , Suelo , Glycine max/crecimiento & desarrollo , Porcinos , Movimientos del Agua
13.
Plant Dis ; 88(11): 1277-1282, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30795325

RESUMEN

The incidence of postharvest fruit rot and associated fungi was studied in stored cranberries in Michigan in 2000 and 2001. Ripe cranberries were harvested from eight commercial farms in southwest and northeast Michigan, including the Upper Peninsula. Eight cranberry cultivars were represented: Stevens, Searles, Le Munyon, Pilgrim, Ben Lear, Bergman, Beckwith, and WSU 61. Fruit rot incidence was assessed within 1 week after harvest. Remaining sound fruit was stored for 2 months at 5°C, and fungi were isolated from rotted fruit after 1 and 2 months of storage. Year and region, but not cultivar, significantly affected the overall rate of rot development in storage. Storage rot levels generally were lower in 2001 than in 2000, particularly in southern Michigan. A high incidence of field rot at harvest did not necessarily lead to a high incidence of storage rot. Storage rot tended to be more severe in the northern than in the southern growing region. Fungi most frequently associated with storage rot were Fusicoccum putrefaciens, Colletotrichum acutatum, Coleophoma empetri, Phomopsis vaccinii, and Phyllosticta elongata. F. putrefaciens was the predominant storage rot fungus in northern Michigan in both years and caused up to 80% fruit rot in storage. C. empetri and P. elongata also were isolated more frequently from beds in northern than southern Michigan in 2001. The cvs. Pilgrim and Stevens were more susceptible to storage rot caused by Colletotrichum acutatum, and Bergman and WSU 61 were more susceptible to storage rot caused by Phomopsis vaccinii than some of the other cultivars.

14.
J Environ Qual ; 32(4): 1436-44, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12931900

RESUMEN

Continued inputs of fertilizer and manure in excess of crop requirements have led to a build-up of soil phosphorus (P) levels and increased P runoff from agricultural soils. The objectives of this study were to determine the effects of two tillage practices (no-till and chisel plow) and a range of soil P levels on the concentration and loads of dissolved reactive phosphorus (DRP), algal-available phosphorus (AAP), and total phosphorus (TP) losses in runoff, and to evaluate the P loss immediately following tillage in the fall, and after six months, in the spring. Rain simulations were conducted on a Typic Argiudoll under a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Elapsed time after tillage (fall vs. spring) was not related to any form of P in runoff. No-till runoff averaged 0.40 mg L(-1) and 0.05 kg ha(-1) DRP and chisel-plow plots averaged 0.24 mg L(-1) and 0.02 kg ha(-1) DRP concentration and loads, respectively. The relationship between DRP and Bray P1 extraction values was approximated by a logistic function (S-shaped curve) for no-till plots and by a linear function for tilled plots. No significant differences were observed between tillage systems for TP and AAP in runoff. Bray P1 soil extraction values and sediment concentration in runoff were significantly related to the concentrations and amounts of AAP and TP in runoff. These results suggest that soil Bray P1 extraction values and runoff sediment concentration are two easily measured variables for adequate prediction of P runoff from agricultural fields.


Asunto(s)
Agricultura , Eutrofización , Fósforo/análisis , Contaminantes del Suelo/análisis , Movimientos del Agua , Contaminantes del Agua/análisis , Monitoreo del Ambiente , Eucariontes , Fertilizantes , Estiércol , Lluvia , Estaciones del Año , Glycine max , Zea mays
15.
J Econ Entomol ; 96(6): 1898-904, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14977131

RESUMEN

Three cultivars of tall fescue, Festuca arundinacea Schreb., were compared with three cultivars each of fine fescue (Festuca spp.), Kentucky bluegrass (Poa pratensis L.), and perennial ryegrass (Lolium perenne L.) to evaluate tolerance to root-feeding by European chafer grubs, Rhizotrogus majalis (Razoumowsky). Potted turfgrasses were infested with initial densities equivalent to 33 or 66 grubs per 0.1 m2 on 19 August 2000. More grubs were added in late September and October, bringing the total to 66 or 143 grubs per 0.1 m2. Plant growth, root loss, weight gain, and survival of grubs were measured. The experiment was repeated in fall of 2001 with an initial density of 66 grubs per 0.1 m2. The proportion of root mass lost as a result of grub feeding was a function of turf species, root growth, grub survival, and grub growth during the test. Grubs gained the most weight and consumed the most roots when feeding on fine fescue. Fine fescue suffered the greatest percentage of root loss in 2000, despite having the most rapid root growth and largest mass in control pots. Cultivars of tall fescue appeared to be the most tolerant of grub feeding, having the smallest reduction in root mass in both years. Data from fine fescue, Kentucky bluegrass, and perennial ryegrass cultivars were not as consistent as tall fescue, because for some cultivars root growth and grub survival were different between years. We also found that grubs increased in mass by 20% when the mass of available roots was doubled.


Asunto(s)
Escarabajos , Poaceae , Animales , Escarabajos/crecimiento & desarrollo , Enfermedades de las Plantas , Hojas de la Planta/crecimiento & desarrollo , Raíces de Plantas/crecimiento & desarrollo , Poaceae/crecimiento & desarrollo , Estaciones del Año , Especificidad de la Especie
16.
Antibiot Khimioter ; 37(1): 17-20, 1992 Jan.
Artículo en Ruso | MEDLINE | ID: mdl-1530352

RESUMEN

The comparative study revealed thymidine phosphorylase activity in the initial strains of a plague microbe of the field variety and in thymidine-, thymine-dependent and trimethoprim-resistant mutants of the plague microbe of other varieties. The data fully conformed to the results of the microbiological investigation of the strains' ability to grow on the nutrient media with trimethoprim in the presence of thymine and thymidine. On the basis of these results it appeared possible to divide the initial and mutant strains of the plague microbe into four arbitrary groups: initial strains of the plague microbe of all the varieties except the field ones sensitive to trimethoprim under any temperature conditions of incubation on any medium with any supplements; initial strains of the plague microbe of the field variety resistant to trimethoprim at 28 degrees C in the presence of thymine or thymidine alone; Tmpr mutants whose resistance to trimethoprim at 28 degrees C did not depend on the presence of thymine or thymidine, purine and vitamins, but depended on the presence of these substances at a temperature of 37 degrees C.


Asunto(s)
Timidina Quinasa/metabolismo , Timidina Fosforilasa/metabolismo , Timidina/metabolismo , Timina/metabolismo , Resistencia al Trimetoprim/genética , Yersinia pestis/efectos de los fármacos , Mutación/genética , Yersinia pestis/genética
17.
Zh Mikrobiol Epidemiol Immunobiol ; (12): 15-8, 1990 Dec.
Artículo en Ruso | MEDLINE | ID: mdl-2099066

RESUMEN

The lytic activity of plague phage II, serovar 3, with respect to 1,800 bacterial strains has been studied: 760 Yersinia pestis strains, 262 Y. pseudotuberculosis strains, 252 Y. enterocolitica strains, 166 Escherichia coli strains, 90 Shigella strains and 270 strains of other species. The phage has been found to lyse 81.8% of Y. pestis strains, 1 Y. pseudotuberculosis strain and 1 Y. enterocolitica strain. The representatives of other 19 bacterial species have proved to be resistant to the phage. Though having a wide range of action within Y. pestis, the phage does not lyse most of the strains of the causative agent of plague, isolated in certain natural foci. This fact offers promise for using the phage for the differentiation of Y. pestis.


Asunto(s)
Bacteriólisis , Bacteriófagos/patogenicidad , Tipificación de Bacteriófagos , Bacteriófagos/clasificación , Lisogenia , Especificidad de la Especie , Yersinia pestis
18.
Mikrobiol Zh (1978) ; 52(4): 84-8, 1990.
Artículo en Ruso | MEDLINE | ID: mdl-2273998

RESUMEN

Strains of all Y. pestis varieties except for those isolated from voles are highly sensitive to trimethoprim when grown on cultivation media, even when thymidine is added to the medium. The ability to grow on thymidine-containing rich media after trimethoprim addition is a property differentiating Y. pestis variety isolated from voles from the other varieties. These data were confirmed by testing 360 Y. pestis strains obtained from collections of several antiplague institutes and stations of the USSR.


Asunto(s)
Arvicolinae/microbiología , Resistencia al Trimetoprim , Yersinia pestis/efectos de los fármacos , Animales , Pruebas de Sensibilidad Microbiana , Timidina/farmacología , Trimetoprim/farmacología , U.R.S.S. , Virulencia , Yersinia pestis/clasificación , Yersinia pestis/aislamiento & purificación , Yersinia pestis/patogenicidad
19.
Mikrobiol Zh (1978) ; 52(2): 39-46, 1990.
Artículo en Ruso | MEDLINE | ID: mdl-2198438

RESUMEN

A method for fractionation of membrane structures of Yersinia pestis is developed. It involves the following basic stages: the cultivation of bacteria in a liquid nutrient medium, mechanical destruction from the solid state in the X-press or ultrasound treatment of the suspension, subsequent two-stage centrifugation in the step (70-15%) and linear (70-45%) gradients of the sucrose density, collection of fractions and their storage. The method makes it possible to separate rapidly and efficiently the outer and cytoplasmic membranes which preserve biochemical and morphological integrity. This is confirmed by the distribution pattern of marker enzyme activities, by the electron microscopic control as well as by other modern sediment tests. High heterogeneity of the polypeptide composition of the isolated membrane preparations has been shown by electrophoresis in PAAG in the presence of sodium dodecyl sulphate as well as definite sensitivity of certain protein subunits to variations of the temperature (28 or 37 degrees C) during cultivation of a plague agent.


Asunto(s)
Yersinia pestis/aislamiento & purificación , Técnicas Bacteriológicas , Fraccionamiento Celular/métodos , Membrana Celular/análisis , Membrana Celular/ultraestructura , Electroforesis en Gel de Poliacrilamida , Membranas Intracelulares/análisis , Membranas Intracelulares/ultraestructura , Microscopía Electrónica , Yersinia pestis/ultraestructura
20.
Artículo en Ruso | MEDLINE | ID: mdl-2728696

RESUMEN

Thymine- and thymidine-dependent mutants of Y. pestis strain EV-76 have been isolated and characterized. Obtaining Y. pestis thymine-dependent mutants in trimethoprim-containing media with full nutritional value in the presence of thymine and thymidine and the capacity of natural strains from the foci of infection in Transcaucasia and Mongolia to grow in such media indicate that Y. pestis has gene tpp controlling thymidine phosphorylase, but this enzyme is strongly suppressed under normal conditions. The capacity for its suppression under definite conditions and the degree of the activation of thymidine phosphorylase determine the realization of Thy and Thyd phenotypes in Y. pestis mutants under study, though both types of these mutants have a mutation damage of gene thy A coding the synthesis of thymidylate synthetase.


Asunto(s)
Timidina/metabolismo , Timidilato Sintasa/metabolismo , Timina/metabolismo , Yersinia pestis/metabolismo , Mutación , Resistencia al Trimetoprim/genética , Yersinia pestis/enzimología , Yersinia pestis/genética
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