[Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: identification of kduD gene]. / Geneticheskaia reguliatsiia faktorov patogennosti i virulentnosti u bakterii Erwinia carotovora subsp. atroseptica. Identifikatsiia gena kduD.

A mutant that cannot utilize pectin substances of plant cell walls was obtained via insertion of mini-mini-Tn5xylE transposon into the chromosome of phytopathogenic bacteria Erwinia carotovora subsp. atroseptica. The inability of mutant cells to utilize these substrates was caused by a failure to accomplish the catabolism of unsaturated digalacturonic acid (UDA). Study of enzymatic activities has established that mutant bacteria lost the ability to produce 2,5-diketo-3-deoxygluconate dehydrogenase, an enzyme of intracellular UDA utilization. Molecular cloning of the mutant gene was conducted, and its nucleotide sequence was determined. It was shown that the nucleotide sequence of this gene had an 82% homology with the sequence of Erwinia chrysanthemi EC3937 kduD gene encoding 2,5-diketo-3-deoxygluconate dehydrogenase. The intergene kdul-kduD region in bacteria Erwinia carotovora subsp. atroseptica is shorter in length by 98 nucleotides than the corresponding region of Erwinia chrysanthemi and does not contain promoter sequences. The kduD gene was located at 126.8 min of the Erwinia carotovora subsp. atroseptica genetic map.

[Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: phenotypic characteristic of bacteria with the mutant kduD gene]. / Geneticheskaia reguliatsiia faktorov patogennosti i virulentnosti u bakterii Erwinia carotovora subsp. atroseptica. Fenotipicheskaia charakteristika mutantnykh po genu kduD bakterii.

In contrast to the closely related bacteria Erwinia chrysanthemi, bacteria Erwinia carotovora subsp. atroseptica produce lower levels of main pathogenicity and virulence factors (pectate lyases, cellulases, and proteases) in the presence of pectins. This effect was shown to be connected with the accumulation of the intermediate product of intracellular degradation of these substances, 2,5-diketo-3-deoxygluconate (DK2). The presence of DK2 in the culture broth of mutant bacteria, connected to its export in the environment, was established. The production of pectate lyases, cellulases, and proteases is repressed by DK2 only at its high concentrations in the cultivation medium, whereas low concentrations of DK2 induce the production of virulence factors. Genes involved in the intracellular catabolism of pectin substances and induced by both low and high DK2 concentrations in the cultivation medium are not repressed by this metabolite.

Bacillus subtilis soil isolates: plasmid replicon analysis and construction of a new theta-replicating vector.

We have searched for plasmids in a collection of 55 Bacillus subtilis strains isolated from various natural sources of the territory of Belarus. Twenty percent of the strains contained one or two plasmids of either 6-8 or approximately 90 kb. Small plasmids were shown to carry a rolling circle replicon of the pC194 type. Four out of the eight large plasmids contained a related theta replicon that has no homolog in databases as shown by sequence determination. A B. subtilis/Escherichia coli shuttle vector based on this replicon was constructed. It has a low copy number (6 units per chromosome) and is stably inherited in B. subtilis. It might thus be a useful tool for DNA cloning. These data extend previous observations, indicating that most of the small plasmids of B. subtilis replicate as rolling circles and belong to the pC194 family. On the contrary, large plasmids appear to form a large pool of theta-replicating determinants, since three different replicons have already been isolated from them.

[Interactions of the phytopathogenic bacteria Erwinia with phage P1 CRL100 CML]. / Osobennosti vzaimodeistviia fitopatogennykh bakterii Errwinia s fagom P1 CRL100 CML.

The bacteriophage P1 Cm clr100 lysogenises the bacteria E. chrysanthemi, E. aroideae, E. atroseptica being localized in the cytoplasm, replicating but causing no cell lysis. The prophage induction results in transformation of the lysogenic bacteria E. chrysanthemi into nonviable filamentous cells. However, a portion of cells gets rid of the prophage and gives rise to normal heritage inheritors permitting to use the bacteriophage as an efficient vehicle for introducing the transposons into the chromosome of E. chrysanthemi. The transposon Tn9 has been found to insert into the different chromosomal sites causing no inactivation of the genes, while the transposition of Tn5 from the bacteriophage P1::Tn5Cmclr100 induces the different mutations with the frequency up to 3%. The bacteriophage P1Cmclr100 may also serve a tool for construction of the homology regions in the chromosome of E. chrysanthemi and Flac+ plasmid for further construction of Hfr-type donors.

[The use of Pseudomonas sp. M plasmid pM3 for the transposon mutagenesis of Erwinia]. / Ispol'zovanie plazmidy pM3 Pseudomonas sp. M dlia transpozonnogo mutageneza bakterii Erwinia.

The transposon containing derivatives pMTF9 (Tn9), pMTF10 (Tn10) and pMTF59 (Tn5, Tn9) of the Pseudomonas sp. M conjugative plasmid pM3 demonstrating temperature-dependent instability in Erwinia cells incubated at 37 degrees C have been isolated. The obtained plasmids have been shown to be usable for transposon-mediated mutability in the bacterial cells of Erwinia generum incubated at 37 degrees C.

[recA-genes of Erwinia chrysanthemi ENA49]. / recA-gen Erwinia chrysanthemi ENA49.

The recA gene of Erwinia chrysanthemi ENA49 has been cloned in vivo in Escherichia coli K12, recA13 cells using the plasmid pULB113. On the basis or DNA repair and recombination deficiencies complementation, of restoration of the inducible "SOS"-response functions the functional identity of the cloned gene with the recA gene was concluded. The recA gene was localized in the 18th min region of the chromosomal genetical map of Erwinia chrysanthemi ENA49 between the genes proA and pheA.

[UV-induced formation of filamentous forms in bacteria of Erwinia genus]. / UF-indutsirovannoe obrazovanie nitevidnykh form u bakterii roda Erwinia.

Cells of 56 pectolytic Erwinia strains of different origin tested are prone to filamentation after UV-irradiation. The fact makes one possible to consider them natural fil+ organisms. Bacteria E. herbicola (9 strains) that are unable to synthesize pectatelyases are not transformed into filaments after NV-irradiation. The function of fil+ genes is recA-dependent in bacteria E. chrysanthemi ENA49 and is phenotypically analogous to fil+ gene function in E. coli B or lon- mutation in E. coli K12.

[Expression of Erwinia chrysanthemi ENA49 uvr gene in Escherichia coli K12 cells]. / Ekspressiia uvr-gena Erwinia chrysanthemi ENA49 v kletkakh Escherichia coli K12.

The uvrA gene of Erwinia chrysanthemi ENA49 similar to uvrA gene of Escherichia coli K12 has been cloned in vivo in Escherichia coli AB1886 uvrA6 cells using the plasmid pULB113 (RP4mini Mu). The presence of pULB113 carrying uvrA gene of Erwinia in Escherichia coli K12 uvrA- cells resulted in suppression of this mutation while uvrB and uvrC are not suppressed by this locus. The genetic control of excision repair of UV-damage in Erwinia chrysanthemi ENA49 is concluded to be similar to the one in Escherichia coli K12.

[Mapping of the locus encoding the bacteriocinogenicity trait in Erwinia chrysanthemi ENA49]. / Kartirovanie lokusa, determiniruiushchego priznak bakteriotsinogennosti u Erwinia chrysanthemi ENA49.

The bacteria Erwinia chrysanthemi ENA49 have been found to produce bacteriocin that is similar in structure to the tail fibers of bacteriophages and suppressing viability of a number of Erwinia, Pseudomonas and Xanthomonas strains. Genetic control of bacteriocin synthesis is determined by the determinants localized on the 68 min of chromosomal genetic map.

[The role of te transposition of Tn1000 from Flac+-plasmid into chromosome of Erwinia chrysanthemi in the formation of Hfr-type donors]. / Rol' transpozitsii Tn1000 iz Flac+-plazmidy v khromosomu Erwinia chrysanthemi v formirovanii donorov Hfr-tipa.

Based on the data of stability of the donor state of Hfr-like strain Erwinia chrysanthemi VY1-10 in RecA+ and RecA- cells, it can be suggested that the donor properties of the strain are mediated by the presence of the genetic homology region which occurred as a result of transposition of the Tn1000 from the Flac+ plasmid into the chromosome of E. chrysanthemi. Tn1000 may be transposed into several sites on the chromosome of E. chrysanthemi ENA49. This leads to the appearance of donors transferring their chromosome from several fixed points oriT and in opposite directions. The location of these points and the direction of transfer are determined by Tn1000 insertion sites and their orientation.

[Conjugational transfer of chromosomal markers in the Erwinia chrysanthemi bacterial system. II. Characteristics of the donor strain of Erwinia chrysanthemi VY1-10]. / Kon"iugatsionnaia peredacha khromosomal'nykh markerov v sisteme bakterii Erwinia chrysanthemi. Soobshchenie II. Kharakteristika donorskogo shtamma Erwinia chrysanthemi VY1-10.

Some properties of the donor Erwinia chrysanthemi VY1-10 strain are similar to those of Hfr donors of Escherichia coli. These are stable inheritance of the Flac plasmid and the capacity for linear and polarized transfer of the chromosome from one oriT site in the following order: O ... thr, leu ... pro ... his. In addition to the ability to transfer its own chromosomal markers, the donor E. chrysanthemi VY1-10 also transfers lac+ marker during initial conjugational steps. The lac+ marker can be detected in recombinants as a structure similar to E. coli K-12 Flac plasmid which was used to obtain the donor strain. It is supposed that such properties are determined either by unusual integration of Flac plasmid or by the unstable Hfr state.

[Conjugation transfer of chromosome markers in an Erwinia chrysanthemi bacterial system. I. Construction of a strain capable of transferring the chromosome during conjugation]. / Kon"iugatsionnaia peredacha khromosomal'nykh markerov v sisteme bakterii Erwinia chrysanthemi. Soobshchenie I. Konstruirovanie shtamma, sposobnogo peredavat' khromosomu pri kon"iugatsii.

The donor strain Erwinia chrysanthemi VY1-10, capable of transferring chromosomal markers at a high frequency (4,7.10(-5)-1,8.10(-3) in crosses with the isogenic polyauxotrophic recipient strain E. chrysanthemi VY7 lac, thr1, leu1, pro1, his2, str-r, was obtained from the strain E. chrysanthemi ENA49 Flac+ (VY1) after growth at 28 degrees on the medium containing acridine orange. Furthermore, the cells of the donor obtained are characterized by stable inheritance of lac+ character.

[Transmission of F'lac plasmid from Escherichia coli K-12 to bacteria of the genus Erwinia]. / Peredacha F'lac-plazmidy ot Escherichia coli K-12 bakteriiam roda Erwinia.

The F'lac plasmid was transferred by conjugation from Escherichia coli K-12 W1655 to 21 lac- strains of Erwinia spp. (5.2 . 10(-6) to 6.8 . 10(-2) lac+ exconjugants per donor cell). Erw. herbicola and Erw. chrysanthemi were the better recipients than others. The degree of the stability of lac+ genes in Erwinia exconjugants depends on the strains. Stable exconjugants of Erwinia, which harbored F'lac plasmid, were able to utilize lactose, to transfer lac genes by conjugation to Erwinia spp. and E. coli, and were sensitive to the F-specific phages f1, f2, Qbeta. The F'lac plasmid was eliminated from the exconjugants by the treatment with acridine orange, which indicates that this genetic element is not integrated into the Erwinia chromosome.