A cryptic plasmid of indigenous Rhizobium meliloti possesses reiterated nodC and nifE genes and undergoes DNA rearrangement

1992 ◽  
Vol 38 (6) ◽  
pp. 563-568 ◽  
Author(s):  
V. K. Rastogi ◽  
E. S. P. Bromfield ◽  
S. T. Whitwill ◽  
L. R. Barran
Keyword(s):  
Genomic Dna ◽  
Rhizobium Meliloti ◽  
Phage Type ◽  
Cryptic Plasmid ◽  
Dna Rearrangement ◽  
Homologous Sequences ◽  
Phage Types ◽  
Phage Sensitivity ◽  
Cryptic Plasmids ◽  
Free Strain

Indigenous Rhizobium meliloti were previously characterized on the basis of plasmid profiles and phage sensitivity patterns (phage types). Rhizobium meliloti 1076, which contained two cryptic plasmids, was one of four isolates comprising phage type 23. In this study, the large cryptic plasmid pVS1(size >500 b) was transferred from isolate 1076 into the plasmid-free strain of Agrobacterium tumefaciens UBAPF1. This plasmid contained nucleotide sequences homologous to genes for nodulation (nodB, nodC) and nitrogen fixation (nifH, nifD, nifK, nifE). Cosmid clones possessing the nod and nif homologous sequences, which had been selected from a genomic bank of A. tumefaciens UBAPF1 containing pVS1, complemented R. meliloti nodC and nifE mutants, respectively. These results demonstrate that the nodC and nifE homologous sequences are functionally expressed. Three of four isolates comprising phage type 23 possessed a megaplasmid band in agarose gels characteristic of R. meliloti, as well as two cryptic plasmids. The fourth isolate (No. 323) lacked the large cryptic plasmid corresponding to pVS1, but instead showed a band of lesser mobility than that of the megaplasmids. Nevertheless, its restricted genomic DNA retained the nodC and nifE hybridizing fragments characteristic of pVS1, indicating that the cryptic plasmid has undergone DNA rearrangement. Key words: Rhizobium, plasmid, reiteration, genes, rearrangement.

Denitrification activity of phage types representative of two populations of indigenous Rhizobium meliloti

1989 ◽  
Vol 35 (7) ◽  
pp. 737-740 ◽  
Author(s):  
Y.-K. Chan ◽  
L. R. Barran ◽  
E. S. P. Bromfield
Keyword(s):  
Medicago Sativa ◽  
Rhizobium Meliloti ◽  
Previous History ◽  
Indigenous Populations ◽  
Frequency Of Occurrence ◽  
Phage Types ◽  
Denitrification Activity ◽  
History Of ◽  
Phage Sensitivity ◽  
Two Populations

Isolates of Rhizobium meliloti from indigenous populations at two sites were previously characterized according to phage sensitivity. Isolates representative of the 55 and 65 phage types comprising these two populations, respectively, were tested for denitrification activity with nitrate or nitrite as substrate. Fifty-seven of 120 isolates were capable of denitrification with activities varying considerably between phage types. Only one isolate was able to denitrify nitrite but not nitrate, indicating the presence of a truncated denitrification pathway. Each of five phage types showed variation in denitrification ability between isolates from different sites, indicating possible adaptation of indigenous R. meliloti to their respective environments. The estimated frequency of occurrence of denitrifiers in the two indigenous populations of R. meliloti (9 and 13%) differed significantly between sites with and without a previous history of Medicago sativa cultivation, respectively.Key words: Rhizobium, denitrification, populations, phage.

scholarly journals Use of bacteriophage typing to distinguish Propionibacterium acne types I and II

1978 ◽  
Vol 7 (1) ◽  
pp. 84-90
Author(s):  
G F Webster ◽  
C S Cummins
Keyword(s):  
Phage Type ◽  
Bacterial Strains ◽  
Propionibacterium Acne ◽  
Bacteriophage Typing ◽  
Phage Types ◽  
Phage Sensitivity ◽  
Selective Lysis

Strains of serotypes I and II of Propionibacterium were compared for phage sensitivity. The two serotypes could be distinguished by using a typing set consisting of 16 bacteriophages at concentrations that demonstrated selective lysis of serotype I or II bacterial strains. Seven phage types were found; three were composed exclusively of serotype I, and four were exclusively composed of serotype II organisms. Generally, serotype I strains were more sensitive to phage lysis than were serotype II strains. No correlation was found between phage type and site of isolation.

Does siderophore production influence the relative abundance of Rhizobium meliloti in two field populations?

1993 ◽  
Vol 39 (3) ◽  
pp. 348-351 ◽  
Author(s):  
L. R. Barran ◽  
E. S. P. Bromfield
Keyword(s):  
Soil Ph ◽  
Relative Abundance ◽  
Iron Content ◽  
Direct Relationship ◽  
Rhizobium Meliloti ◽  
Siderophore Production ◽  
Frequency Of Occurrence ◽  
Apparent Absence ◽  
Phage Types ◽  
Phage Sensitivity

Populations of indigenous Rhizobium meliloti isolated from nodules of alfalfa grown at sites A and B (soil pH, 7.0 and 6.1, respectively) were previously characterized on the basis of phage sensitivity and divided into 55 and 65 phage types. The available iron content of soil at site B was significantly higher than that at site A. Isolates representing the phage types comprising each of these populations were tested for the production of siderophores. The frequency of siderophore-producing (sid+) phage types of R. meliloti, estimated from the distribution of types in the two field populations, was significantly higher at site A (54%), where iron was less available, than at site B (18%). The distributions of frequency for sid+ and sid− phage types were similar at site A but differed (P < 0.005) at site B, where the soil was slightly acidic and contained more available iron. The apparent absence of a direct relationship between siderophore production and frequency of occurrence suggests that siderophore production may not influence the relative abundance of R. meliloti in these populations at sites differing in iron availability.Key words: siderophore, iron, Rhizobium meliloti, populations.

Symbiotic gene probes hybridize to cryptic plasmids of indigenous Rhizobium meliloti

1988 ◽  
Vol 34 (5) ◽  
pp. 703-707 ◽  
Author(s):  
L. R. Barran ◽  
E. S. P. Bromfield
Keyword(s):  
Dna Sequences ◽  
Rhizobium Meliloti ◽  
Dna Probes ◽  
Cryptic Plasmid ◽  
Nodule Development ◽  
Nif Genes ◽  
Symbiotic Gene ◽  
Gene Probes ◽  
Cryptic Plasmids

DNA probes for host specific nodulation (hsn) common nodulation (nod), exopolysaccharide (exo), nodule development (ndv) and nitrogenase structural (nif) genes were used to examine a collection of symbiotically effective, genotypically distinct isolates of indigenous Rhizobium meliloti for reiteration of symbiotic DNA sequences on cryptic plasmids. Nineteen of 30 isolates possessed at least one cryptic plasmid with reiterated DNA sequences, and of these isolates 15, 5, and 1 contained cryptic plasmids that hybridized to hsn, nif, and nod gene probes respectively; both hsn and nif probes hybridized to a single cryptic plasmid in each of two isolates. The exo and ndv probes did not hybridize to cryptic plasmids in any of the 30 isolates of R. meliloti.

scholarly journals Molecular epidemiology and diversity ofSalmonellaserovar Typhimurium in pigs using phenotypic and genotypic approaches

2005 ◽  
Vol 134 (1) ◽  
pp. 187-198 ◽  
Author(s):  
W. A. GEBREYES ◽  
C. ALTIER ◽  
S. THAKUR
Keyword(s):  
Production Systems ◽  
Phage Type ◽  
Geographical Area ◽  
Multidrug Resistant ◽  
Resistance Pattern ◽  
Public Health Importance ◽  
Pig Production ◽  
Phage Types ◽  
Serovar Typhimurium ◽  
Discriminatory Index

SUMMARYFor epidemiological investigations of the most common and non-host-adaptedSalmonellaserotypes, such as Typhimurium, highly discriminatory approaches are essential. In the present study, we evaluated three genotyping methods; amplified fragment length polymorphism (AFLP), pulsed-field gel electrophoresis (PFGE) and repetitive palindromic extragenic–PCR (Rep–PCR) using 40 isolates. AFLP showed the highest discriminatory index (0·939), resolution and throughput. To determine clonality ofSalmonellaTyphimurium isolates and epidemiological relatedness in different commercial pig production units, we employed AFLP in combination with antimicrobial resistance pattern and phage typing.Salmonellaserovar Typhimurium isolates (n=196) obtained from a longitudinal study of 18 pig farms over a 3-year period were studied. Using this approach, 16 distinct clonal types were identified. We found two common multidrug- resistant patterns including AmCmStSuTe and AmKmStSuTe. Two commonly multidrug- resistant phage types that are of known public health importance, DT104 and DT193, were also common. AFLP differentiated distinct clones within DT104, a phage type previously reported to be clonal. Fourteen of the clonal types were unique to one of the two production systems, showing diversity between independent commercial pig production systems located in the same geographical area. Clonal types obtained from nursery farms and corresponding finishing units were, however, similar.

Genetic Transformation of Streptococcus sanguis (Challis) with Cryptic Plasmids from Streptococcus ferus

1980 ◽  
Vol 28 (3) ◽  
pp. 692-699 ◽  
Author(s):  
Francis L. Macrina ◽  
Patricia H. Wood ◽  
Kevin R. Jones
Keyword(s):  
Genetic Transformation ◽  
Streptococcus Mutans ◽  
Restriction Enzyme ◽  
Deoxyribonucleic Acid ◽  
Cryptic Plasmid ◽  
Common Ancestry ◽  
Erythromycin Resistance ◽  
Streptococcus Sanguis ◽  
Cryptic Plasmids ◽  
Isogenic Strains

By using the basic methodology initially published by Kretschmer et al. (J. Bacteriol. 124 :225-231, 1975), we have been able to introduce phenotypically cryptic plasmids from Streptococcus ferus (formerly Streptococcus mutans subsp. ferus ) into Streptococcus sanguis by genetic transformation. In this system, the entry of the cryptic plasmids is selected indirectly. This is effected with transforming deoxyribonucleic acid mixtures in which the cryptic plasmid deoxyribonucleic acid is present in an approximate 10-fold molar excess with respect to a plasmid (pVA1) known to confer erythromycin resistance. Under such conditions, 5 to 10% of the pVA1-containing erythromycin-resistant transformants were cotransformed with cryptic plasmid deoxyribonucleic acid. pVA1 may be selectively eliminated by growth of its S. sanguis host strain at 42°C, enabling the construction of isogenic strains with and without S. ferus cryptic plasmids. Comparative physiological studies of such strains have failed to reveal any plasmid-conferred phenotypes in S. sanguis. With this procedure, we have been able to physically separate two small cryptic plasmids (2.4 × 10 6 and 2.8 × 10 6 daltons) of S. ferus. Although these plasmids were found naturally to exist in a single S. ferus host, they were able to replicate independently of one another in S. sanguis. Restriction enzyme fingerprinting indicated that these plasmids did not share a common ancestry.

scholarly journals A Simple Method for Assessing Diversity and Dynamics of Microbial Community: Comparison of Dairy Phages from Industrial and Spontaneous Fermentation

2021 ◽  
Vol 11 (19) ◽  
pp. 8915
Author(s):  
Agnieszka Olejnik-Schmidt ◽  
Bernadeta Pietrzak ◽  
Iwona Kawacka ◽  
Klaudia Malak ◽  
Weronika Wawrzyniak ◽  
...  
Keyword(s):  
Phage Type ◽  
Low Complexity ◽  
Universal Primers ◽  
Spontaneous Fermentation ◽  
Simple Method ◽  
Protective Measures ◽  
Production Methods ◽  
Phage Types ◽  
Quality Product ◽  
Sanger Method

Background: The dairy industry heavily relies on fermentation processes driven in high proportion by Lactococcus lactis. The fermentation process can be perturbed or even stopped by bacteriophage activity, leading to complete loss of fermentation batch or decreased quality product. The monitoring of the phage diversity and dynamics in the process allows implementing protective measures (e.g., starter rotation) to maintain unperturbed production. Methods: Universal primers were used to amplify sequences of the 936, c2, and P335 Lactococcus phage types. The amplicons were sequenced with the Sanger method and obtained degenerate sequences were analyzed using a simple bioinformatic pipeline in the R environment. Results: The most prevalent phage type is 936, followed by P335, whereas the c2 type is less frequent. Conclusions: Curd cheeses prepared on non-pasteurized milk based on native milk microbiota had a higher diversity of phages distinct from those found in dairy plants. Sanger sequencing of heterogenous amplicons generated on metagenome DNA can be used to assess low-complexity microbiota diversity.

scholarly journals Genotypic Characterization of Salmonella enteritidis Phage Types by Plasmid Analysis, Ribotyping, and Pulsed-Field Gel Electrophoresis

1998 ◽  
Vol 36 (8) ◽  
pp. 2314-2321 ◽  
Author(s):  
A. M. Ridley ◽  
E. J. Threlfall ◽  
B. Rowe
Keyword(s):  
Gel Electrophoresis ◽  
Salmonella Enteritidis ◽  
Profile Analysis ◽  
Phage Type ◽  
Plasmid Profile ◽  
Pulsed Field Gel Electrophoresis ◽  
Single Type ◽  
Pulsed Field ◽  
Phage Types ◽  
Reference Strains

Pulsed-field gel electrophoresis (PFGE) was used to resolveXbaI and SpeI macrorestriction fragments from 60 defined phage type (PT) reference strains of Salmonella enteritidis. The level of discrimination was compared to that afforded by plasmid profile analysis and ribotyping. Twenty-eight distinct XbaI pulsed-field profiles (PFPs) were observed, although a single type, PFP X1, predominated. Absence of the 57-kbspv-associated fragment was observed for three PT reference strains, and the profile was designated PFP X1A. The XbaI macrorestriction profiles of a further four PT reference strains were altered by the presence of plasmid-associated bands. Twenty-sixSpeI-generated PFPs (plus one subtype) were observed for the same strains. No SpeI fragment corresponding to the 38-MDa serovar-specific plasmid was detected. The distribution ofXbaI and SpeI profiles did not always correspond, producing a total of 32 combined PFPs for the 60 PT reference strains. This compared with a total of 18 different plasmid profiles and three PvuII ribotypes generated by the same strains. The results of this study indicate that PFGE may offer an improved level of discrimination over other genotypic typing methods for the epidemiological typing of S. enteritidis.

scholarly journals Salmonella Enteritidis in England and Wales: increases in unusual phage types in 2002

2002 ◽  
Vol 6 (45) ◽  
Author(s):  
S O’Brien ◽  
L Ward
Keyword(s):  
Public Health ◽  
Salmonella Enteritidis ◽  
Phage Type ◽  
Enteric Pathogens ◽  
Public Health Laboratory ◽  
England And Wales ◽  
Laboratory Service ◽  
The Public ◽  
Phage Types

Although Salmonella Enteritidis phage type (PT) 4, responsible for the major epidemic during the late 1980s and early 1990s (1), has continued to decline, there have been increases in a number of the more unusual phage types of S. Enteritidis (2). Isolates of S. Enteritidis PT 3, 6a, 13a and 14b and 21 confirmed by the Public Health Laboratory Service Laboratory of Enteric Pathogens (PHLS LEP) in England have all increased during 2002 (table 1) (3).

scholarly journals Salmonella Typhimurium in livestock in Great Britain – trends observed over a 32-year period

2018 ◽  
Vol 146 (4) ◽  
pp. 409-422 ◽  
Author(s):  
D. Mueller-Doblies ◽  
K. C. R. Speed ◽  
S. Kidd ◽  
R. H. Davies
Keyword(s):  
Retrospective Study ◽  
Great Britain ◽  
Antimicrobial Resistance ◽  
Phage Type ◽  
Livestock Species ◽  
Phage Types ◽  
Specific Phage ◽  
Resistance Patterns ◽  
Over Time

AbstractIn this retrospective study, we describe and analyse Salmonella data from four livestock species in Great Britain between 1983 and 2014, focusing on Salmonella Typhimurium. A total of 96 044 Salmonella isolates were obtained during the study period. S. Typhimurium was the predominant serovar isolated from cattle and pigs and represented 40.7% (18 455/45 336) and 58.3% (4495/7709) of isolates from these species respectively, while it only accounted for 6.7% (2114/31 492) of chicken isolates and 8.1% (926/11 507) of turkey isolates. Over the study period, DT104 was the most common phage type in all four species; however, DT104 peaked in occurrence between 1995 and 1999, but is currently rare.Monophasic strains of S. Typhimurium represented less than 3% of all Salmonella isolates in cattle and chickens in 2014, but accounted for 10.4% of all turkey isolates and 39.0% of all pig isolates in the same year.Salmonella isolates were tested for their in vitro susceptibility to 16 antimicrobials. Antimicrobial resistance of S. Typhimurium isolates is largely influenced by the dominance of specific phage types at a certain time, which are commonly associated with particular resistance patterns. Changes in resistance patterns over time were analysed and compared between species.

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