scholarly journals Plasmid Replicons for the Production of Pharmaceutical-Grade pDNA, Proteins and Antigens by Lactococcus lactis Cell Factories

2021 ◽  
Vol 22 (3) ◽  
pp. 1379
Author(s):  
Sofia O.D. Duarte ◽  
Gabriel A. Monteiro
Keyword(s):  
Lactococcus Lactis ◽  
Recombinant Proteins ◽  
Plasmid Copy Number ◽  
Fermented Food ◽  
Added Value ◽  
Regulatory Sequences ◽  
Plasmid Copy ◽  
Mucosal Vaccination ◽  
Cell Factories ◽  
Plasmid Replicons

The Lactococcus lactis bacterium found in different natural environments is traditionally associated with the fermented food industry. But recently, its applications have been spreading to the pharmaceutical industry, which has exploited its probiotic characteristics and is moving towards its use as cell factories for the production of added-value recombinant proteins and plasmid DNA (pDNA) for DNA vaccination, as a safer and industrially profitable alternative to the traditional Escherichia coli host. Additionally, due to its food-grade and generally recognized safe status, there have been an increasing number of studies about its use in live mucosal vaccination. In this review, we critically systematize the plasmid replicons available for the production of pharmaceutical-grade pDNA and recombinant proteins by L. lactis. A plasmid vector is an easily customized component when the goal is to engineer bacteria in order to produce a heterologous compound in industrially significant amounts, as an alternative to genomic DNA modifications. The additional burden to the cell depends on plasmid copy number and on the expression level, targeting location and type of protein expressed. For live mucosal vaccination applications, besides the presence of the necessary regulatory sequences, it is imperative that cells produce the antigen of interest in sufficient yields. The cell wall anchored antigens had shown more promising results in live mucosal vaccination studies, when compared with intracellular or secreted antigens. On the other side, engineering L. lactis to express membrane proteins, especially if they have a eukaryotic background, increases the overall cellular burden. The different alternative replicons for live mucosal vaccination, using L. lactis as the DNA vaccine carrier or the antigen producer, are critically reviewed, as a starting platform to choose or engineer the best vector for each application.

scholarly journals Increased Exopolysaccharide Production in Lactococcus lactis due to Increased Levels of Expression of the NIZO B40 eps Gene Cluster

2003 ◽  
Vol 69 (8) ◽  
pp. 5029-5031 ◽  
Author(s):  
Ingeborg C. Boels ◽  
Richard van Kranenburg ◽  
Marja W. Kanning ◽  
Barrie Fong Chong ◽  
Willem M. de Vos ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Lactococcus Lactis ◽  
Plasmid Copy Number ◽  
Fermented Food ◽  
Activity Level ◽  
Production Level ◽  
Plasmid Copy ◽  
Fourfold Increase ◽  
Homologous Overexpression ◽  
Threefold Increase

ABSTRACT Exopolysaccharides (EPS) play an important role in the rheology and texture of fermented food products. This is the first report demonstrating that homologous overexpression of a complete eps gene cluster in Lactococcus lactis leads to increased EPS production levels. A ninefold-elevated EPS plasmid copy number led to an almost threefold increase in the eps expression level, resulting in an almost fourfold increase in the NIZO B40 EPS production level. It was previously reported that increased EPS precursor levels did not influence NIZO B40 EPS production levels. However, the present results indicate that the maximal NIZO B40 EPS production level is limited by the activity level of the expression products of the eps gene cluster rather than by the level of EPS precursors.

scholarly journals Separate Roles of Escherichia coliReplication Proteins in Synthesis and Partitioning of pSC101 Plasmid DNA

1999 ◽  
Vol 181 (24) ◽  
pp. 7552-7557 ◽  
Author(s):  
Christine Miller ◽  
Stanley N. Cohen
Keyword(s):  
Dna Replication ◽  
Plasmid Dna ◽  
Plasmid Copy Number ◽  
Temperature Sensitive ◽  
Replication Proteins ◽  
Plasmid Copy ◽  
Plasmid Partitioning ◽  
Bacterial Replication ◽  
Cell Membrane Binding ◽  
Plasmid Replicons

ABSTRACT We report here that the Escherichia coli replication proteins DnaA, which is required to initiate replication of both the chromosome and plasmid pSC101, and DnaB, the helicase that unwinds strands during DNA replication, have effects on plasmid partitioning that are distinct from their functions in promoting plasmid DNA replication. Temperature-sensitive dnaB mutants cultured under conditions permissive for DNA replication failed to partition plasmids normally, and when cultured under conditions that prevent replication, they showed loss of the entire multicopy pool of plasmid replicons from half of the bacterial population during a single cell division. As was observed previously for DnaA, overexpression of the wild-type DnaB protein conversely stabilized the inheritance of partition-defective plasmids while not increasing plasmid copy number. The identification of dnaA mutations that selectively affected either replication or partitioning further demonstrated the separate roles of DnaA in these functions. The partition-related actions of DnaA were localized to a domain (the cell membrane binding domain) that is physically separate from the DnaA domain that interacts with other host replication proteins. Our results identify bacterial replication proteins that participate in partitioning of the pSC101 plasmid and provide evidence that these proteins mediate plasmid partitioning independently of their role in DNA synthesis.

scholarly journals Structural Elements Required for Replication and Incompatibility of the Rhizobium etli Symbiotic Plasmid

2000 ◽  
Vol 182 (11) ◽  
pp. 3117-3124 ◽  
Author(s):  
Miguel A. Ramírez-Romero ◽  
Nora Soberón ◽  
Angeles Pérez-Oseguera ◽  
Juan Téllez-Sosa ◽  
Miguel A. Cevallos
Keyword(s):  
Plasmid Copy Number ◽  
Intergenic Sequence ◽  
Structural Elements ◽  
Rhizobium Etli ◽  
Plasmid Copy ◽  
Plasmid Segregation ◽  
Symbiotic Plasmid ◽  
Conserved Genes ◽  
Dna Strand ◽  
Plasmid Replicons

ABSTRACT The symbiotic plasmid of Rhizobium etli CE3 belongs to the RepABC family of plasmid replicons. This family is characterized by the presence of three conserved genes, repA,repB, and repC, encoded by the same DNA strand. A long intergenic sequence (igs) between repBand repC is also conserved in all members of the plasmid family. In this paper we demonstrate that (i) the repABCgenes are organized in an operon; (ii) the RepC product is essential for replication; (iii) RepA and RepB products participate in plasmid segregation and in the regulation of plasmid copy number; (iv) there are two cis-acting incompatibility regions, one located in the igs (incα) and the other downstream ofrepC (incβ) (the former is essential for replication); and (v) RepA is a trans-acting incompatibility factor. We suggest that incα is acis-acting site required for plasmid partitioning and that the origin of replication lies within incβ.

scholarly journals Chlamydia trachomatis intra-bacterial and total plasmid copy number in clinical urogenital samples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. A. M. C. Dirks ◽  
K. Janssen ◽  
C. J. P. A. Hoebe ◽  
T. H. B. Geelen ◽  
M. Lucchesi ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Diagnostic Value ◽  
Plasmid Copy Number ◽  
Extracellular Dna ◽  
Chromosomal Dna ◽  
Plasmid Copy ◽  
Clinical Sensitivity ◽  
Copy Numbers ◽  
Vaginal Swabs ◽  
And Gender

AbstractChlamydia trachomatis (CT) increases its plasmid numbers when stressed, as occurs in clinical trachoma samples. Most CT tests target the plasmid to increase the test sensitivity, but some only target the chromosome. We investigated clinical urogenital samples for total plasmid copy numbers to assess its diagnostic value and intra-bacterial plasmid copy numbers to assess its natural variation. Both plasmid and chromosome copies were quantified using qPCR, and the plasmid:chromosome ratio (PCr) calculated in two cohorts: (1) 383 urogenital samples for the total PCR (tPCr), and (2) 42 vaginal swabs, with one half treated with propium-monoazide (PMA) to prevent the quantification of extracellular DNA and the other half untreated to allow for both tPCr and intra-bacterial PCr (iPCr) quantification. Mann–Whitney U tests compared PCr between samples, in relation to age and gender. Cohort 1: tPCr varied greatly (1–677, median 16). Median tPCr was significantly higher in urines than vaginal swabs (32 vs. 11, p < 0.001). Cohort 2: iPCr was more stable than tPCr (range 0.1–3 vs. 1–11). To conclude, tPCr in urogenital samples was much more variable than previously described. Transport time and temperature influences DNA degradation, impacting chromosomal DNA more than plasmids and urine more than vaginal samples. Data supports a plasmid target in CT screening assays to increase clinical sensitivity.

scholarly journals Segregational Drift and the Interplay between Plasmid Copy Number and Evolvability

2018 ◽  
Vol 36 (3) ◽  
pp. 472-486 ◽  
Author(s):  
Judith Ilhan ◽  
Anne Kupczok ◽  
Christian Woehle ◽  
Tanita Wein ◽  
Nils F Hülter ◽  
...  
Keyword(s):  
Copy Number ◽  
Plasmid Copy Number ◽  
Plasmid Copy

scholarly journals RNA polyadenylation and its consequences in prokaryotes

2018 ◽  
Vol 373 (1762) ◽  
pp. 20180166 ◽  
Author(s):  
Eliane Hajnsdorf ◽  
Vladimir R. Kaberdin
Keyword(s):  
Gene Expression ◽  
State Level ◽  
Rna Degradation ◽  
Plasmid Copy Number ◽  
Plasmid Copy ◽  
Protein Coding ◽  
Mrna Metabolism ◽  
Isolation And Characterization ◽  
Polymerase I ◽  
The Impact

Post-transcriptional addition of poly(A) tails to the 3′ end of RNA is one of the fundamental events controlling the functionality and fate of RNA in all kingdoms of life. Although an enzyme with poly(A)-adding activity was discovered in Escherichia coli more than 50 years ago, its existence and role in prokaryotic RNA metabolism were neglected for many years. As a result, it was not until 1992 that E. coli poly(A) polymerase I was purified to homogeneity and its gene was finally identified. Further work revealed that, similar to its role in surveillance of aberrant nuclear RNAs of eukaryotes, the addition of poly(A) tails often destabilizes prokaryotic RNAs and their decay intermediates, thus facilitating RNA turnover. Moreover, numerous studies carried out over the last three decades have shown that polyadenylation greatly contributes to the control of prokaryotic gene expression by affecting the steady-state level of diverse protein-coding and non-coding transcripts including antisense RNAs involved in plasmid copy number control, expression of toxin–antitoxin systems and bacteriophage development. Here, we review the main findings related to the discovery of polyadenylation in prokaryotes, isolation, and characterization and regulation of bacterial poly(A)-adding activities, and discuss the impact of polyadenylation on prokaryotic mRNA metabolism and gene expression. This article is part of the theme issue ‘5′ and 3′ modifications controlling RNA degradation’.

scholarly journals Plasmid copy number noise in monoclonal populations of bacteria

2010 ◽  
Vol 81 (1) ◽  
Author(s):  
Jérôme Wong Ng ◽  
Didier Chatenay ◽  
Jérôme Robert ◽  
Michael Guy Poirier
Keyword(s):  
Copy Number ◽  
Plasmid Copy Number ◽  
Plasmid Copy
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