scholarly journals Genetic Studies on Phage DNA Mixed Infection of Purified Phage DNA and Other Active Phage Partcles

1959 ◽  
Vol 34 (8) ◽  
pp. 253-260
Author(s):  
Masanaka TERADA ◽  
Isamu KONDO
Keyword(s):  
Mixed Infection ◽  
Genetic Studies ◽  
Phage Dna

scholarly journals Dissection of the Bacteriophage Mu Strong Gyrase Site (SGS): Significance of the SGS Right Arm in Mu Biology and DNA Gyrase Mechanism

2006 ◽  
Vol 188 (2) ◽  
pp. 619-632 ◽  
Author(s):  
Mark Oram ◽  
Andrew A. Travers ◽  
Alison J. Howells ◽  
Anthony Maxwell ◽  
Martin L. Pato
Keyword(s):  
Dna Gyrase ◽  
Distal Portion ◽  
Bacteriophage Mu ◽  
Genetic Studies ◽  
Dnase I Footprinting ◽  
Dependent Change ◽  
Phage Dna ◽  
The Right ◽  
Dna Complex

ABSTRACT The bacteriophage Mu strong gyrase site (SGS), required for efficient phage DNA replication, differs from other gyrase sites in the efficiency of gyrase binding coupled with a highly processive supercoiling activity. Genetic studies have implicated the right arm of the SGS as a key structural feature for promoting rapid Mu replication. Here, we show that deletion of the distal portion of the right arm abolishes efficient binding, cleavage, and supercoiling by DNA gyrase in vitro. DNase I footprinting analysis of the intact SGS revealed an adenylyl imidodiphosphate-dependent change in protection in the right arm, indicating that this arm likely forms the T segment that is passed through the cleaved G segment during the supercoiling reaction. Furthermore, in an SGS derivative with an altered right-arm sequence, the left arm showed these changes, suggesting that the selection of a T segment by gyrase is determined primarily by the sequences of the arms. Analysis of the sequences of the SGS and other gyrase sites suggests that the choice of T segment correlates with which arm possesses the more extensive set of phased anisotropic bending signals, with the Mu right arm possessing an unusually extended set of such signals. The implications of these observations for the structure of the gyrase-DNA complex and for the biological function of the Mu SGS are discussed.

scholarly journals 7-Deazaguanine modifications protect phage DNA from host restriction systems

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Geoffrey Hutinet ◽  
Witold Kot ◽  
Liang Cui ◽  
Roman Hillebrand ◽  
Seetharamsingh Balamkundu ◽  
...  
Keyword(s):  
Genomic Dna ◽  
Restriction Enzymes ◽  
Arms Race ◽  
Genetic Studies ◽  
Host Restriction ◽  
Archaeal Viruses ◽  
Phage Dna ◽  
Genome Modifications

AbstractGenome modifications are central components of the continuous arms race between viruses and their hosts. The archaeosine base (G+), which was thought to be found only in archaeal tRNAs, was recently detected in genomic DNA of Enterobacteria phage 9g and was proposed to protect phage DNA from a wide variety of restriction enzymes. In this study, we identify three additional 2′-deoxy-7-deazaguanine modifications, which are all intermediates of the same pathway, in viruses: 2′-deoxy-7-amido-7-deazaguanine (dADG), 2′-deoxy-7-cyano-7-deazaguanine (dPreQ0) and 2′-deoxy-7- aminomethyl-7-deazaguanine (dPreQ1). We identify 180 phages or archaeal viruses that encode at least one of the enzymes of this pathway with an overrepresentation (60%) of viruses potentially infecting pathogenic microbial hosts. Genetic studies with the Escherichia phage CAjan show that DpdA is essential to insert the 7-deazaguanine base in phage genomic DNA and that 2′-deoxy-7-deazaguanine modifications protect phage DNA from host restriction enzymes.

Monoclonal Antibodies Raised against Native Major Capsid Proteins of Lactococcal c2-Like Bacteriophages

1998 ◽  
Vol 64 (11) ◽  
pp. 4255-4259 ◽  
Author(s):  
Sandra R. Chibani Azaïez ◽  
Ismaïl Fliss ◽  
Ronald E. Simard ◽  
Sylvain Moineau
Keyword(s):  
Monoclonal Antibodies ◽  
Competitive Inhibition ◽  
Cell Extract ◽  
Capsid Proteins ◽  
Enzyme Linked Immunosorbent Assay ◽  
Genetic Studies ◽  
Protein Renaturation ◽  
Phage Dna ◽  
Molecular Masses ◽  
Phage Proteins

ABSTRACT Phage Q38, a representative member of the c2 species, was purified by CsCl gradient and used to immunize BALB/c mice. Monoclonal antibodies (MAbs) were raised and then characterized by enzyme-linked immunosorbent assay. Two MAbs of isotype immunoglobulin G2a, designated 2A5 and 6G7, reacted only with phages belonging to the c2 species and not with phages of the 936 and P335 species, with a Lactococcus lactis cell extract, or with phage DNA. Immunoelectron microscopy showed that both MAbs recognized only phage head proteins. They did not react with any denatured phage proteins in Western blot assays. However, when the nitrocellulose membranes were treated with a Triton-based buffer to assist in protein renaturation, MAbs 2A5 and 6G7 recognized the two major capsid proteins with molecular masses of 80 and 170 kDa. Competitive inhibition tests showed that the two MAbs bind to overlapping epitopes. These MAbs may be a useful tool for monitoring c2 bacteriophages during dairy fermentation and in genetic studies.

scholarly journals Biochemical and genetic analysis of lambdaW, the newly isolated lambdoid phage.

1998 ◽  
Vol 45 (1) ◽  
pp. 251-259
Author(s):  
B Wróbel ◽  
S Srutkowska ◽  
G Wegrzyn
Keyword(s):  
Electron Microscopy ◽  
Restriction Analysis ◽  
Low Frequency ◽  
Amino Acid Starvation ◽  
Genetic Studies ◽  
E Coli ◽  
Bacterial Response ◽  
Lambdoid Phage ◽  
Stringent Control ◽  
Phage Dna

Otherwise isogenic Escherichia coli CP78 (relA+) and CP79 (relA-) strains are commonly used in studies on the stringent control, the bacterial response to amino acid starvation. We found that these strains are lysogenic for a phage which is spontaneously induced with a low frequency, producing virions able to infect other E. coli strains. Genetic studies, restriction analysis of the phage DNA genome, and electron microscopy revealed that this phage is very similar to, but not identical with, bacteriophage lambda. We called the newly isolated phage lambdaW, and found that most of CP78/CP79 ancestor strains are lysogenic for this phage.

Replication of Bacteriophage 186 DNA

1972 ◽  
Vol 30 ◽  
pp. 194-195
Author(s):  
Dhruba K. Chattoraj ◽  
Ross B. Inman
Keyword(s):  
Electron Microscopy ◽  
Dna Replication ◽  
Frame Of Reference ◽  
Dna Molecules ◽  
E Coli ◽  
Phage Dna ◽  
Partial Denaturation

Electron microscopy of replicating intermediates has been quite useful in understanding the mechanism of DNA replication in DNA molecules of bacteriophage, mitochondria and plasmids. The use of partial denaturation mapping has made the tool more powerful by providing a frame of reference by which the position of the replicating forks in bacteriophage DNA can be determined on the circular replicating molecules. This provided an easy means to find the origin and direction of replication in λ and P2 phage DNA molecules. DNA of temperate E. coli phage 186 was found to have an unique denaturation map and encouraged us to look into its mode of replication.

Moving beyond the “LDL hypothesis”

VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 333-340 ◽  
Author(s):  
Christian Werner ◽  
Ulrich Laufs
Keyword(s):  
Ldl Cholesterol ◽  
Causal Relation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Clinical Trial Data ◽  
Randomised Clinical Trial ◽  
Trial Data ◽  
Low Density Lipoprotein Cholesterol ◽  
Genetic Studies ◽  
Statin Drug

Abstract. Summary: The term “LDL hypothesis” is frequently used to describe the association of low-density lipoprotein cholesterol (LDL-cholesterol, LDL-C) and cardiovascular (CV) events. Recent data from genetic studies prove a causal relation between serum LDL-C and CV events. These data are in agreement with mechanistic molecular studies and epidemiology. New randomised clinical trial data show that LDL-C lowering with statins and a non-statin drug, ezetimibe, reduces CV events. We therefore believe that the “LDL-hypothesis” has been proven; the term appears to be outdated and should be replaced by “LDL causality”.

Neuropsychological intermediate phenotypes as tools for genetic studies in schizophrenia

2009 ◽  
Vol 42 (05) ◽  
Author(s):  
H Konnerth ◽  
I Giegling ◽  
AM Hartmann ◽  
J Genius ◽  
A Ruppert ◽  
...  
Keyword(s):  
Genetic Studies ◽  
Intermediate Phenotypes

The Use of Medical Record Linkage for Population and Genetic Studies

1969 ◽  
Vol 08 (01) ◽  
pp. 07-11 ◽  
Author(s):  
H. B. Newcombe
Keyword(s):  
Record Linkage ◽  
Large Scale ◽  
Medical Record Linkage ◽  
Canadian Province ◽  
Genetic Studies ◽  
Parental Characteristics ◽  
Family Histories ◽  
The Family ◽  
Large Populations ◽  
Machine Readable

Methods are described for deriving personal and family histories of birth, marriage, procreation, ill health and death, for large populations, from existing civil registrations of vital events and the routine records of ill health. Computers have been used to group together and »link« the separately derived records pertaining to successive events in the lives of the same individuals and families, rapidly and on a large scale. Most of the records employed are already available as machine readable punchcards and magnetic tapes, for statistical and administrative purposes, and only minor modifications have been made to the manner in which these are produced.As applied to the population of the Canadian province of British Columbia (currently about 2 million people) these methods have already yielded substantial information on the risks of disease: a) in the population, b) in relation to various parental characteristics, and c) as correlated with previous occurrences in the family histories.

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