INSTABILITY OF HIGHER PLANT CHROMOSOMAL DNA MOLECULARLY CLONED IN E. COLI VIA RECOMBINANT PLASMIDS  Supported by NSF Grant #PCM77-15011, USDA/SEA Grants # 5901-0410-8-0068-0 and 5901-0410-8-0045, NIH Grants # GM21454 and GM00048.

1979 ◽  
pp. 586
Author(s):  
Virginia K. Eckenrode ◽  
Harald Friedrich ◽  
Ron T. Nagao ◽  
Sidney R. Kushner ◽  
Richard B. Meagher
Keyword(s):  
Chromosomal Dna ◽  
Higher Plant ◽  
E Coli ◽  
Recombinant Plasmids

scholarly journals Identification and Characterization of CAMP Cohemolysin as a Potential Virulence Factor of Riemerella anatipestifer

2002 ◽  
Vol 184 (7) ◽  
pp. 1932-1939 ◽  
Author(s):  
Karen C. Crasta ◽  
Kim-Lee Chua ◽  
Sumathi Subramaniam ◽  
Joachim Frey ◽  
Hilda Loh ◽  
...  
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Chromosomal Dna ◽  
Pcr Cloning ◽  
Reading Frame ◽  
E Coli ◽  
Recombinant Plasmids ◽  
Riemerella Anatipestifer ◽  
Hydrolysis Of

ABSTRACT Riemerella anatipestifer is responsible for exudative septicemia in ducks. The genetic determinant of the CAMP cohemolysin, cam, from a strain of R. anatipestifer was cloned and expressed in Escherichia coli. Chromosomal DNA from serotype 19 strain 30/90 was used to construct a gene library in pBluescript II SK(−) vector in E. coli XL-1-Blue strain. The clones containing recombinant plasmids were screened for the CAMP reaction with Staphylococcus aureus. Those that showed cohemolysis were chosen for further analysis by sequencing. One of these clones, JFRA8, was subcloned to identify the smallest possible DNA fragment containing the CAMP cohemolysin determinant, which was located on a 3,566-bp BamHI-BstXI fragment which specified a 1,026-bp open reading frame. Clones containing recombinant plasmids carrying cam obtained by PCR cloning into E. coli M15 strain secreted an active CAMP cohemolysin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses confirmed that the recombinant strain expressed a protein with a molecular mass of 37 kDa and that strains from serotypes 1, 2, 3, 5, 6, and 19 expressed the cohemolysin. The deduced amino acid sequence showed high homology to those of O-sialoglycoprotein endopeptidases. Hydrolysis of radioiodinated glycophorin A confirmed that Cam is a sialoglycoprotease.

Characterization and heterologous expression of testosterone-inducible regulator fromComamonas testosteroniinEscherichia coli

2009 ◽  
Vol 6 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Chen Jian-Qiu ◽  
Ai Yu-Fang ◽  
Zhou Yi-Fei ◽  
Pan Da-Ren ◽  
Xiong Guang-Ming ◽  
...  
Keyword(s):  
Protein Expression ◽  
Expression Level ◽  
Enzyme Linked Immunosorbent Assay ◽  
Comamonas Testosteroni ◽  
Chromosomal Dna ◽  
Protein Expression Level ◽  
E Coli ◽  
Recombinant Plasmids ◽  
Encoding Gene ◽  
The Relationship

AbstractThe testosterone-inducible regulator (teiR) gene was cloned fromComamonas testosteronichromosomal DNA, and introduced into plasmids pKtac2 (containing atacpromoter) and pK18 to yield plasmids pKtac2-teiRand pKteiR100. The recombinant plasmids were transformed into competentEscherichia coliHB101 and total protein was extracted to detect the TeiR protein expression level using enzyme-linked immunosorbent assay (ELISA).E. colitransformed by pKtac2-teiRand pKteiR100produced 6.65 and 5.93 μg/mg of TeiR protein, respectively. Recombinant plasmids were also co-transformed into competentE. coliHB101 with plasmid p6 [containinghsdAgene (3α-HSD/CR, 3α-hydroxysteroid dehydrogenase/carbonyl reductase encoding gene)] to reveal the relationship between 3α-HSD/CR and TeiR by ELISA. The amounts of TeiR protein expressed byE. colicontaining pKtac2-teiRand pKteiR100were 5.94 μg/mg and 5.33 μg/mg, respectively, and these increased up to 6.81 μg/mg and 6.10 μg/mg after inducing with 1 mmol/l isopropyl-β-d-thiogalactoside (IPTG). Interestingly, 3α-HSD/CR protein expression level, after co-transformation with plasmids pKtac2-teiRand p6, was lower than that observed in the co-transformation with pKteiR100and p6. The first co-transformation induced 1.20 μg/mg 3α-HSD/CR protein and the second 1.71 μg/mg. These values rose to 1.42 and 1.80 μg/mg, respectively, after treatment with 1 mmol/l IPTG. Our results proved that thetacpromoter was more efficient than thelacZpromoter and that theteiRgene could act as an activator forhsdAgene expression.

scholarly journals Genetic Organization of the Vibrio harveyi dnaA Gene Region and Analysis of the Function of the V. harveyi DnaA Protein in Escherichia coli

2002 ◽  
Vol 184 (9) ◽  
pp. 2533-2538 ◽  
Author(s):  
Dvora Berenstein ◽  
Kirsten Olesen ◽  
Christian Speck ◽  
Ole Skovgaard
Keyword(s):  
Escherichia Coli ◽  
Promoter Region ◽  
Vibrio Harveyi ◽  
Gene Region ◽  
Chromosomal Dna ◽  
Dnaa Gene ◽  
E Coli ◽  
Dnaa Protein ◽  
Dam Methylase ◽  
And Function

ABSTRACT The Vibrionaceae family is distantly related to Enterobacteriaceae within the group of bacteria possessing the Dam methylase system. We have cloned, sequenced, and analyzed the dnaA gene region of Vibrio harveyi and found that although the organization of the V. harveyi dnaA region differs from that of Escherichia coli, the expression of both genes is autoregulated and ATP-DnaA binds cooperatively to ATP-DnaA boxes in the dnaA promoter region. The DnaA proteins of V. harveyi and E. coli are interchangeable and function nearly identically in controlling dnaA transcription and the initiation of chromosomal DNA replication despite the evolutionary distance between these bacteria.

scholarly journals Vibrio cholerae VibF Is Required for Vibriobactin Synthesis and Is a Member of the Family of Nonribosomal Peptide Synthetases

2000 ◽  
Vol 182 (6) ◽  
pp. 1731-1738 ◽  
Author(s):  
Joan R. Butterton ◽  
Michael H. Choi ◽  
Paula I. Watnick ◽  
Patricia A. Carroll ◽  
Stephen B. Calderwood
Keyword(s):  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Consensus Sequence ◽  
Membrane Receptor ◽  
Transcriptional Level ◽  
Outer Membrane Receptor ◽  
Chromosomal Dna ◽  
E Coli ◽  
Binding Consensus Sequence

ABSTRACT A 7.5-kbp fragment of chromosomal DNA downstream of theVibrio cholerae vibriobactin outer membrane receptor,viuA, and the vibriobactin utilization gene,viuB, was recovered from a Sau3A lambda library of O395 chromosomal DNA. By analogy with the genetic organization of the Escherichia coli enterobactin gene cluster, in which the enterobactin biosynthetic and transport genes lie adjacent to the enterobactin outer membrane receptor, fepA, and the utilization gene, fes, the cloned DNA was examined for the ability to restore siderophore synthesis to E. coli entmutants. Cross-feeding studies demonstrated that an E. coli entF mutant complemented with the cloned DNA regained the ability to synthesize enterobactin and to grow in low-iron medium. Sequence analysis of the cloned chromosomal DNA revealed an open reading frame downstream of viuB which encoded a deduced protein of greater than 2,158 amino acids, homologous to Yersinia sp. HMWP2, Vibrio anguillarum AngR, and E. coliEntF. A mutant with an in-frame deletion of this gene, namedvibF, was created with classical V. choleraestrain O395 by in vivo marker exchange. In cross-feeding studies, this mutant was unable to synthesize ferric vibriobactin but was able to utilize exogenous siderophore. Complementation of the mutant with a cloned vibF fragment restored vibriobactin synthesis to normal. The expression of the vibF promoter was found to be negatively regulated by iron at the transcriptional level, under the control of the V. cholerae fur gene. Expression ofvibF was not autoregulatory and neither affected nor was affected by the expression of irgA or viuA. The promoter of vibF was located by primer extension and was found to contain a dyad symmetric nucleotide sequence highly homologous to the E. coli Fur binding consensus sequence. A footprint of purified V. cholerae Fur on the vibFpromoter, overlapping the Fur binding consensus sequence, was observed using DNase I footprinting. The protein product of vibF is homologous to the multifunctional nonribosomal protein synthetases and is necessary for the biosynthesis of vibriobactin.

Expression and bioactivity of recombinant segments of human perforinThis paper is one of a selection of papers in this Special Issue, entitled International Symposium on Recent Advances in Molecular, Clinical, and Social Medicine, and has undergone the Journal's usual peer-review process.

2007 ◽  
Vol 85 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Hongmei Dong ◽  
Xiaohu Xu ◽  
Mohong Deng ◽  
Xiaojun Yu ◽  
Hu Zhao ◽  
...  
Keyword(s):  
Recombinant Proteins ◽  
Fusion Proteins ◽  
Target Genes ◽  
Review Process ◽  
Peer Review Process ◽  
Nitrilotriacetic Acid ◽  
E Coli ◽  
Recombinant Plasmids ◽  
Expression Plasmids ◽  
Selection Of

The aim of the study was to prepare an active recombinant human perforin by comparing 5 candidate segments of human perforin. Full-length perforin, MAC1 (28–349 aa), MAC2 (166–369 aa), C-100, and N-60 of human perforin were selected as candidate active segments and designated, respectively, HP1, HP2, HP3, HP4, and HP5. The target genes were amplified by PCR and the products were individually subcloned into pGEM-T. The genes for HP1, HP2, HP3, and HP5 were subcloned into pET-DsbA, whereas pET-41a (+) was used as the expression vector of HP4. The fusion proteins were expressed in Escherichia coli BL21pLysS(DE3) and purified using nickel nitrilotriacetic acid (NTA) agarose affinity chromatography. The hemolysis microassay was used as an activity assay of fusion protein. From this study, we obtained the recombinant plasmids pGEM-T-HP1, -HP2, -HP3, -HP4 and -HP5, consisting of 1600, 960, 600, 300bp, and 180, respectively. From these recombinant plasmids, expression plasmids were successfully constructed and expressed in E. coli BL21pLysS(DE3). The resultant fusion proteins, affinity purified using Ni–NTA, were ~80, 58, 45, 44, and 30 kDa, respectively. The recombinant proteins were assayed for activity on hemolysis. HP2 and HP5 were the only recombinant proteins that were active in hemolysis, and the hemolytic function was concentration dependent. These results demonstrate that active recombinant forms of perforin can be synthesized in a prokaryote model. The recombinant N-60 and MAC1 (28–349 aa) of human perforin have the function of forming pores. Our study provides the experimental basis for further investigation on the application of perforin.

scholarly journals The Production of the Recombinant Protein of Anthrax Bacteriolysine PlyPH and In Vitro Study of the Lytic Properties of the Protein Coded for them Against Bacillus anhracis Microbial Cells

2019 ◽  
pp. 5-22
Author(s):  
Onuchina N.V., Soybanov V.D.
Keyword(s):  
In Vitro Study ◽  
Coli Strain ◽  
Vitro Study ◽  
Chromosomal Dna ◽  
Lytic Enzymes ◽  
Microbial Cells ◽  
Phage Gene ◽  
E Coli ◽  
Species Specific

The causative agent of anthrax - Bacillus anthracis, due to the prevalence of its natural foci in Russia, high virulence for humans and most mammals, the unique resistance of spore forms to environmental factors and repeated use in terrorist acts, is an extremely dangerous biological agent. Therefore, the search for new effective drugs for the diagnosis and treatment of anthrax, including diseases caused by antibiotic-resistant strains of B. anthracis is necessary. The use of lytic enzymes of species-specific bacteriophages is a new trend in the diagnosis, prevention and treatment of infectious diseases. The goal of this work is the cloning of the anthrax bacteriolysin PlyPH gene as part of the pTrcHis2C vector in Escherichia coli and the in vitro study of the lytic properties of the protein encoded by it against B. anthracis microbial cells. According to the complete sequencing of the B. anthracis genomes of the Ames, Stern 34F2 and JB17 strains, a prophage was found in their chromosomal DNA, which lost part of the structural genes necessary for its replication, but retained a gene with a high degree of homology with the bacteriolysin γ phage gene. For amplification and subsequent cloning of the PlyPH gene, we developed primers containing EcoRI and BamHI restriction enzyme recognition sites. Amplification of the PlyPH gene in a polymerase chain reaction (PCR) with a developed pair of primers was performed using the Stern 34F2 strain of the anthrax microbe as a template. Based on the obtained amplification products and the pTrcHis2C vector, we constructed a recombinant plasmid containing the bacteriolysin synthesis PlyPH gene and stably functioning in the cells of the recombinant E. coli strain. In the course of research, it has been established that microbial cells of the E. coli recombinant TOP10 strain provide for the production of the bacteriolysin of the anthrax prophage, PlyPH , which has the ability to in vitro lyse the vegetative cells of the STI-1 vaccine strain of B. anthracis

scholarly journals Supercoil Levels in E. coli and Salmonella Chromosomes Are Regulated by the C-Terminal 35–38 Amino Acids of GyrA

2019 ◽  
Vol 7 (3) ◽  
pp. 81 ◽  
Author(s):  
Nikolay Rovinskiy ◽  
Andrews Agbleke ◽  
Olga Chesnokova ◽  
N. Higgins
Keyword(s):  
Essential Gene ◽  
Wild Type ◽  
Chromosomal Dna ◽  
E Coli ◽  
Sister Chromosome ◽  
Negative Supercoiling ◽  
Close Relatives ◽  
Negative Supercoils

Prokaryotes have an essential gene—gyrase—that catalyzes negative supercoiling of plasmid and chromosomal DNA. Negative supercoils influence DNA replication, transcription, homologous recombination, site-specific recombination, genetic transposition and sister chromosome segregation. Although E. coli and Salmonella Typhimurium are close relatives with a conserved set of essential genes, E. coli DNA has a supercoil density 15% higher than Salmonella, and E. coli cannot grow at the supercoil density maintained by wild type (WT) Salmonella. E. coli is addicted to high supercoiling levels for efficient chromosomal folding. In vitro experiments were performed with four gyrase isoforms of the tetrameric enzyme (GyrA2:GyrB2). E. coli gyrase was more processive and faster than the Salmonella enzyme, but Salmonella strains with chromosomal swaps of E. coli GyrA lost 40% of the chromosomal supercoil density. Reciprocal experiments in E. coli showed chromosomal dysfunction for strains harboring Salmonella GyrA. One GyrA segment responsible for dis-regulation was uncovered by constructing and testing GyrA chimeras in vivo. The six pinwheel elements and the C-terminal 35–38 acidic residues of GyrA controlled WT chromosome-wide supercoiling density in both species. A model of enzyme processivity modulated by competition between DNA and the GyrA acidic tail for access to β-pinwheel elements is presented.

scholarly journals Biophysical Properties of Escherichia coli Cytoplasm in Stationary Phase by Superresolution Fluorescence Microscopy

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Yanyu Zhu ◽  
Mainak Mustafi ◽  
James C. Weisshaar
Keyword(s):  
Escherichia Coli ◽  
Fluorescence Microscopy ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Mean Square Displacement ◽  
Quiescent State ◽  
Chromosomal Dna ◽  
Content Type ◽  
E Coli

ABSTRACT In nature, bacteria must survive long periods of nutrient deprivation while maintaining the ability to recover and grow when conditions improve. This quiescent state is called stationary phase. The biochemistry of Escherichia coli in stationary phase is reasonably well understood. Much less is known about the biophysical state of the cytoplasm. Earlier studies of harvested nucleoids concluded that the stationary-phase nucleoid is “compacted” or “supercompacted,” and there are suggestions that the cytoplasm is “glass-like.” Nevertheless, stationary-phase bacteria support active transcription and translation. Here, we present results of a quantitative superresolution fluorescence study comparing the spatial distributions and diffusive properties of key components of the transcription-translation machinery in intact E. coli cells that were either maintained in 2-day stationary phase or undergoing moderately fast exponential growth. Stationary-phase cells are shorter and exhibit strong heterogeneity in cell length, nucleoid volume, and biopolymer diffusive properties. As in exponential growth, the nucleoid and ribosomes are strongly segregated. The chromosomal DNA is locally more rigid in stationary phase. The population-weighted average of diffusion coefficients estimated from mean-square displacement plots is 2-fold higher in stationary phase for both RNA polymerase (RNAP) and ribosomal species. The average DNA density is roughly twice as high as that in cells undergoing slow exponential growth. The data indicate that the stationary-phase nucleoid is permeable to RNAP and suggest that it is permeable to ribosomal subunits. There appears to be no need to postulate migration of actively transcribed genes to the nucleoid periphery. IMPORTANCE Bacteria in nature usually lack sufficient nutrients to enable growth and replication. Such starved bacteria adapt into a quiescent state known as the stationary phase. The chromosomal DNA is protected against oxidative damage, and ribosomes are stored in a dimeric structure impervious to digestion. Stationary-phase bacteria can recover and grow quickly when better nutrient conditions arise. The biochemistry of stationary-phase E. coli is reasonably well understood. Here, we present results from a study of the biophysical state of starved E. coli. Superresolution fluorescence microscopy enables high-resolution location and tracking of a DNA locus and of single copies of RNA polymerase (the transcription machine) and ribosomes (the translation machine) in intact E. coli cells maintained in stationary phase. Evidently, the chromosomal DNA remains sufficiently permeable to enable transcription and translation to occur. This description contrasts with the usual picture of a rigid stationary-phase cytoplasm with highly condensed DNA.

scholarly journals Molecular analysis of Escherichia coli O157 strains isolated from cattle and pigs by the use of PCR and pulsed-field gel electrophoresis methods

2012 ◽  
Vol 47 (No. 6) ◽  
pp. 149-158 ◽  
Author(s):  
J. Osek ◽  
P. Gallien
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Rflp Analysis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Chromosomal Dna ◽  
E Coli ◽  
Shiga Toxin Genes ◽  
Porcine Origin

Fourteen Escherichia coli O157 strains isolated from cattle and pigs in Poland and in Germany were investigated, using PCR, for the genetic markers associated with Shiga toxin-producing E. coli (STEC). Only two strains, both of cattle origin, were positive for the fliC (H7) gene and could be classified as O157 : H7. Nine isolates had stx shiga toxin genes, either stx1 (1 strain), stx2 (4 isolates) or both (4 strains). The stx2-carrying samples were further subtyped by PCR for the stx2c, stx2d, and stx2e toxin variants. It was shown that all but one stx2-positive bacteria possessed the stx2c Shiga toxin gene type and one stx2 STEC isolate had the stx2d virulence factor sub-type. The eaeA (intimin) gene was found in 9 strains (8 isolates from cattle and one strain from pigs); all of them harboured the genetic marker characteristic of the gamma intimin variant. The translocated intimin receptor (tir) gene was detected in 7 isolates tested and among them only one tir-positive strain was recovered from pigs. The ehly E. coli enterohemolysin gene was amplified in all but one strains obtained from cattle and only in one isolate of porcine origin. The genetic relatedness of the analysed E. coli O157 strains was examined by restriction fragment length polymorphism (RFLP) of chromosomal DNA digested with XbaI. Two distinct but related RFLP pattern clusters were observed: one with 9 strains (8 isolates of bovine origin and one strain obtained from pigs) and the other one comprises the remaining 5 E. coli isolates (4 of porcine origin and one strain recovered from cattle). The results suggest that pigs, besides cattle, may be a reservoir of E. coli O157 strains potentially pathogenic to humans. Moreover, epidemiologically unrelated isolates of the O157 serogroup, recovered from different animal species, showed a clonal relationship as demonstrated by the RFLP analysis.

Cloning and molecular analysis of promoter-like sequences isolated from the chromosomal DNA ofLactobacillus acidophilusATCC 4356

1997 ◽  
Vol 43 (1) ◽  
pp. 61-69 ◽  
Author(s):  
G. Djordjevic ◽  
B. Bojovic ◽  
N. Miladinov ◽  
L. Topisirovic
Keyword(s):  
Lactococcus Lactis ◽  
Molecular Analysis ◽  
Lactobacillus Acidophilus ◽  
Promoter Activity ◽  
Lactobacillus Reuteri ◽  
Bacterial Species ◽  
Chromosomal Dna ◽  
Complementary Dna ◽  
E Coli ◽  
Dna Strand

Promoter-like sequences from the chromosomal DNA of thermophilic strain Lactobacillus acidophilus ATCC 4356 were cloned. Analysis of the three DNA fragments showing promoter activity, designated P3, P6, and P15, were performed in Lactobacillus reuteri, Lactococcus lactis, and E. coli. The reporter cat-86 gene was expressed in all three bacterial species under control of the fragments P3 and P6. Fragment P15 showed promoter activity only in Lactobacillus reuteri and E. coli but not in Lactococcus lactis. The three host-specific transcriptional start points (TSPs) were used when transcription of the cat-86 gene was controlled by fragment P3 in Lactobacillus reuteri, E. coli, and Lactococcus lactis. Similarly, fragment P15 initiated transcription of the cat-86 gene at two distinctive sites in Lactobacillus reuteri and E. coli. Only within fragment P6, a common TSP was used in Lactobacillus reuteri and E. coli, but different from that used in Lactococcus lactis. Each TSP was preceded by the putative −35 and −10 hexamers. Computer analysis of the fragment P3 sequence revealed the existence of divergent promoterlike sequence (P3rev) located on the complementary DNA strand. Fragments P6 and P15 were also functional in Lactobacillus acidophilus ATCC 4356 from which chromosomal DNA they were originally cloned.Key words: Lactobacillus acidophilus, promoter-like sequences, regulation.

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