scholarly journals Characterization of lactococci isolated from homemade kefir

2007 ◽  
Vol 59 (1) ◽  
pp. 13-22 ◽  
Author(s):  
M. Kojic ◽  
Jelena Lozo ◽  
Jelena Begovic ◽  
B. Jovcic ◽  
Lj. Topisirovic
Keyword(s):  
Dna Hybridization ◽  
Antimicrobial Compounds ◽  
Plasmid Curing ◽  
Natural Isolate ◽  
Bacteriocin Activity ◽  
Proteinase Production ◽  
Genes Encoding ◽  
Traditionally Prepared ◽  
Cross Inhibition

Five bacteriocin-producing lactococci isolates from traditionally prepared kefir were determined as Lactococcus lactis subsp. lactis. The analyzed isolates showed different plasmid profiles and no cross inhibition between them was detected. Moreover, natural isolate BGKF26 was resistant to the antimicrobial activity of nisin producing strain NP45. Plasmid curing experiments revealed that the genes encoding bacteriocin and proteinase production are located on separate genetic elements, except in BGKF26. Production of the tested bacteriocins depends on the concentration of casitone or triptone in the medium. Higher concentrations of casitone or triptone induce bacteriocin activity. Our DNA-DNA hybridization analyses suggest that the analyzed antimicrobial compounds probably are lactococcin-like bacteriocins.

Proteinase PI and lactococcin A genes are located on the largest plasmid inLactococcus lactissubsp.lactisbv. diacetylactis S50

2005 ◽  
Vol 51 (4) ◽  
pp. 305-314 ◽  
Author(s):  
Milan Kojic ◽  
Ivana Strahinic ◽  
Ljubisa Topisirovic
Keyword(s):  
Dna Hybridization ◽  
Cell Envelope ◽  
Bacteriocin Production ◽  
Conjugative Plasmid ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Plasmid Curing ◽  
Test Frequency ◽  
Genes Encoding ◽  
Large Plasmids

Lactococcus lactis subsp. lactis bv. diacetylactis S50 produces a lactococcin A-like bacteriocin named bacteriocin S50, and cell envelope-associated PI-type proteinase activity. This strain harbours 3 small size plasmids: pS6 (6.3 kb), pS7a (7.31 kb), and pS7b (7.27 kb). Plasmid curing using a combination of novobiocin treatment (10 µg·mL–1) and sublethal temperature (40 °C) resulted in a very low yield (0.17%) of Prt–, Bac–, Bacsderivatives, which retained all 3 small size resident plasmids. Pulsed-field gel electrophoresis of DNA isolated from the strain S50 and cured derivatives in combination with restriction enzyme analysis and DNA–DNA hybridization revealed that S50 contains 2 additional large plasmids: pS140 (140 kb) and pS80 (80 kb). Conjugation experiments using strain S50 as a donor and various lactococcal recipients resulted in Prt+, Bac+, Bacrtransconjugants. Analysis of these transconjugants strongly indicated that plasmid pS140 harbours the prt and bac genes encoding proteinase and bacteriocin production, and immunity to bacteriocin, since each Prt+, Bac+, Bacrtranconjugant contained pS140. Accordingly, none of the Prt–, Bac–, Bacstransconjugants contained this plasmid. pS140 was a self-transmissible conjugative plasmid regardless of the host lactococcal recipient used in the test. Frequency of conjugation of plasmid pS140 did not depend on either the donor or recipient strain.Key words: Lactococcus, plasmids, conjugation, bacteriocin, proteinase.

Isolation and characterization of the genes encoding antimicrobial neutrophil cationic peptides, defensins.

Ensho ◽  
1995 ◽  
Vol 15 (1) ◽  
pp. 33-41
Author(s):  
Isao Nagaoka ◽  
Noriko Ishihara ◽  
Akimasa Someya ◽  
Kazuhisa Iwabuchi ◽  
Shin Yomogida ◽  
...  
Keyword(s):  
Cationic Peptides ◽  
Isolation And Characterization ◽  
Genes Encoding

scholarly journals Protein complex formation in methionine chain-elongation and leucine biosynthesis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Qun Chen ◽  
Shweta Chhajed ◽  
Tong Zhang ◽  
Joseph M. Collins ◽  
Qiuying Pang ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Complete Characterization ◽  
Bimolecular Fluorescence Complementation ◽  
Chain Elongation ◽  
Substrate Channeling ◽  
Leucine Biosynthesis ◽  
Protein Complex Formation ◽  
Genes Encoding ◽  
Isopropylmalate Dehydrogenase

AbstractDuring the past two decades, glucosinolate (GLS) metabolic pathways have been under extensive studies because of the importance of the specialized metabolites in plant defense against herbivores and pathogens. The studies have led to a nearly complete characterization of biosynthetic genes in the reference plant Arabidopsis thaliana. Before methionine incorporation into the core structure of aliphatic GLS, it undergoes chain-elongation through an iterative three-step process recruited from leucine biosynthesis. Although enzymes catalyzing each step of the reaction have been characterized, the regulatory mode is largely unknown. In this study, using three independent approaches, yeast two-hybrid (Y2H), coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC), we uncovered the presence of protein complexes consisting of isopropylmalate isomerase (IPMI) and isopropylmalate dehydrogenase (IPMDH). In addition, simultaneous decreases in both IPMI and IPMDH activities in a leuc:ipmdh1 double mutants resulted in aggregated changes of GLS profiles compared to either leuc or ipmdh1 single mutants. Although the biological importance of the formation of IPMI and IPMDH protein complexes has not been documented in any organisms, these complexes may represent a new regulatory mechanism of substrate channeling in GLS and/or leucine biosynthesis. Since genes encoding the two enzymes are widely distributed in eukaryotic and prokaryotic genomes, such complexes may have universal significance in the regulation of leucine biosynthesis.

scholarly journals Molecular characterization of clinical carbapenem-resistant Enterobacterales from Qatar

2021 ◽  
Author(s):  
Fatma Ben Abid ◽  
Clement K. M. Tsui ◽  
Yohei Doi ◽  
Anand Deshmukh ◽  
Christi L. McElheny ◽  
...  
Keyword(s):  
Common Species ◽  
Clinical Samples ◽  
Whole Genome ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Genes Encoding ◽  
Encoding Genes ◽  
Sequence Types ◽  
Common Sequence

AbstractOne hundred forty-nine carbapenem-resistant Enterobacterales from clinical samples obtained between April 2014 and November 2017 were subjected to whole genome sequencing and multi-locus sequence typing. Klebsiella pneumoniae (81, 54.4%) and Escherichia coli (38, 25.5%) were the most common species. Genes encoding metallo-β-lactamases were detected in 68 (45.8%) isolates, and OXA-48-like enzymes in 60 (40.3%). blaNDM-1 (45; 30.2%) and blaOXA-48 (29; 19.5%) were the most frequent. KPC-encoding genes were identified in 5 (3.6%) isolates. Most common sequence types were E. coli ST410 (8; 21.1%) and ST38 (7; 18.4%), and K. pneumoniae ST147 (13; 16%) and ST231 (7; 8.6%).

scholarly journals Host Range of Streptomycete Strains Causing Common Scab

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 901-904 ◽  
Author(s):  
Claudia Goyer ◽  
Carole Beaulieu
Keyword(s):  
Host Range ◽  
Daucus Carota ◽  
Dna Hybridization ◽  
Common Scab ◽  
Genetic Cluster ◽  
Dna Relatedness ◽  
Physiological Characterization ◽  
Genetic Clusters ◽  
High Level

Ten Streptomyces isolates from common scab lesions on carrots (Daucus carota) were characterized. Morphological and physiological characterization of the carrot isolates established that they were closely related to S. scabies. DNA-DNA hybridization studies were carried out between DNA from the carrot isolates and DNA from two potato strains belonging to the two genetic clusters of S. scabies. Most of the carrot isolates exhibited a high level of DNA relatedness (average of 90%) to strain EF-54, which belongs to genetic cluster 1 of S. scabies. Three carrot isolates could not be included in either S. scabies genetic cluster 1 or 2. The pathogenicity of six S. scabies isolates from potato or carrot, two isolates of S. caviscabies, and one isolate of S. acidiscabies was determined on potato, carrot, radish, beet, turnip, and parsnip. All S. scabies isolates were pathogenic on carrot and radish, but pathogenicity on beet, parsnip, turnip, and potato was variable. Even though S. acidiscabies and S. caviscabies until now have been isolated only from potato, we demonstrated that isolates of these species also could infect other crops, such as radish, carrot, parsnip, and turnip.

Electrical frequency dependent characterization of DNA hybridization

2003 ◽  
Vol 19 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Marin Gheorghe ◽  
Anthony Guiseppi-Elie
Keyword(s):  
Dna Hybridization ◽  
Frequency Dependent
Sign in / Sign up

Export Citation Format

Share Document