Evidence and characterization of a gene cluster required for the production of viscosin, a lipopeptide biosurfactant, by a strain ofPseudomonas fluorescens

2001 ◽  
Vol 47 (4) ◽  
pp. 294-301 ◽  
Author(s):  
P Gordon Braun ◽  
Paul D Hildebrand ◽  
Tim C Ells ◽  
Donald Y Kobayashi
Keyword(s):  
Wild Type ◽  
Chromosomal Dna ◽  
Fatty Acid Component ◽  
Intimate Contact ◽  
Amino Acid Peptide ◽  
Lipopeptide Biosurfactant ◽  
To Come ◽  
Head Rot ◽  
Mutagenized Cell

The genetic control of viscosin production was examined in a strain of Pseudomonas fluorescens (PfA7B) that causes broccoli head rot. Viscosin is a potent lipopeptide biosurfactant that enables the bacteria to come into intimate contact with the difficult-to-wet waxy heads of broccoli. Tn5 mutagenesis completely disrupted viscosin production as shown by HPLC analysis of the mutagenized cell lysates. The Vis–mutants retained their pectolytic capability and were able to decay potato slices. On broccoli, however, the Vis–mutants caused decay of wounded florets, but the decay failed to spread to adjacent nonwounded florets as had occurred with the wild-type PfA7B. Triparental matings of the Vis–mutants with their corresponding wild-type clones and the helper Escherichia coli HB101 carrying the mobilization plasmid pPK2013 resulted in three stable viscosin-producing transconjugants that caused typical decay of broccoli tissue. Linkage maps of clones and protein profiles showed that a 25-kb chromosomal DNA region of PfA7B affected the production of three high molecular mass proteins required for viscosin synthesis. These proteins, approximately 218, 215, and 137 kDa in size, likely compose a synthetase complex that assembles the nine amino acid peptide of viscosin and subsequently attaches this to the hydrophobic fatty acid component of the molecule. A probe made from this DNA region hybridized with DNA fragments of other phytopathogenic pseudomonads to varying degrees.Key words: virulence factor, head rot, broccoli.

scholarly journals Purification and Characterization of aBacillus subtilis168 Nuclease, YokF, Involved in Chromosomal DNA Degradation and Cell Death Caused by Thermal Shock Treatments

2001 ◽  
Vol 276 (50) ◽  
pp. 47046-47051 ◽  
Author(s):  
Jin J. Sakamoto ◽  
Miho Sasaki ◽  
Tetsuaki Tsuchido
Keyword(s):  
Thermal Shock ◽  
Nuclease Activity ◽  
Dna Degradation ◽  
Wild Type ◽  
Chromosomal Dna ◽  
Purification And Characterization ◽  
Membrane Perturbation

We purified and characterized a 39-kDaBacillus subtilis168 nuclease that has been suggested in this laboratory to be involved in chromosomal DNA degradation induced by lethal heat and cold shock treatmentsin vivo. The nuclease activity was inhibitedin vitroby aurintricalboxylic acid but not by Zn2+. By the mutant analysis, we identified the 39-kDa nuclease as a product ofyokFgene. TheyokFgene contained a putative lipoprotein signal peptide motif. Afterin vivoexposure to lethal heat and cold stresses, the chromosomal DNA fragmentation was reduced in theyokFmutant, which demonstrated about a 2–10-fold higher survival rate than the wild type. TheyokFmutant was found to be more sensitive to mitomycin C than the wild type. The transformation efficiency of theyokFmutant was about 10 times higher than that of the wild type. It is suggested that whenB. subtiliscells are exposed to a stressful thermal shock resulting in membrane perturbation, YokF nuclease consequently dislocates into the cytoplasm and then attacks DNA.

Functional characterization of the H+/K+ ATPase in wild type and gastrin knock-out mice

2007 ◽  
Vol 45 (05) ◽  
Author(s):  
A Schnur ◽  
P Hegyi ◽  
V Venglovecz ◽  
Z Rakonczay ◽  
I Ignáth ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Wild Type ◽  
Knock Out ◽  
Knock Out Mice

scholarly journals Isolation and characterization of plasma membranes from wild type Neurospora crassa.

1981 ◽  
Vol 256 (23) ◽  
pp. 12336-12342 ◽  
Author(s):  
E.J. Bowman ◽  
B.J. Bowman ◽  
C.W. Slayman
Keyword(s):  
Neurospora Crassa ◽  
Plasma Membranes ◽  
Wild Type ◽  
Isolation And Characterization

scholarly journals Genetic mapping and transcriptomic characterization of a new fuzzless-tufted cottonseed mutant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qian-Hao Zhu ◽  
Warwick Stiller ◽  
Philippe Moncuquet ◽  
Stuart Gordon ◽  
Yuman Yuan ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Agronomic Traits ◽  
Gene Families ◽  
Mutant Phenotype ◽  
Wild Type ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Flanking Region ◽  
Comparative Transcriptomic Analysis

Abstract Fiber mutants are unique and valuable resources for understanding the genetic and molecular mechanisms controlling initiation and development of cotton fibers that are extremely elongated single epidermal cells protruding from the seed coat of cottonseeds. In this study, we reported a new fuzzless-tufted cotton mutant (Gossypium hirsutum) and showed that fuzzless-tufted near-isogenic lines (NILs) had similar agronomic traits and a higher ginning efficiency compared to their recurrent parents with normal fuzzy seeds. Genetic analysis revealed that the mutant phenotype is determined by a single incomplete dominant locus, designated N5. The mutation was fine mapped to an approximately 250-kb interval containing 33 annotated genes using a combination of bulked segregant sequencing, SNP chip genotyping, and fine mapping. Comparative transcriptomic analysis using 0–6 days post-anthesis (dpa) ovules from NILs segregating for the phenotypes of fuzzless-tufted (mutant) and normal fuzzy cottonseeds (wild-type) uncovered candidate genes responsible for the mutant phenotype. It also revealed that the flanking region of the N5 locus is enriched with differentially expressed genes (DEGs) between the mutant and wild-type. Several of those DEGs are members of the gene families with demonstrated roles in cell initiation and elongation, such as calcium-dependent protein kinase and expansin. The transcriptome landscape of the mutant was significantly reprogrammed in the 6 dpa ovules and, to a less extent, in the 0 dpa ovules, but not in the 2 and 4 dpa ovules. At both 0 and 6 dpa, the reprogrammed mutant transcriptome was mainly associated with cell wall modifications and transmembrane transportation, while transcription factor activity was significantly altered in the 6 dpa mutant ovules. These results imply a similar molecular basis for initiation of lint and fuzz fibers despite certain differences.

scholarly journals The Mutant Phenotype Associated With P-Element Alleles of the vestigial Locus in Drosophila melanogaster May Be Caused by a Readthrough Transcript Initiated at the P-Element Promoter

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1665-1672 ◽  
Author(s):  
Ross B Hodgetts ◽  
Sandra L O'Keefe
Keyword(s):  
Rna Secondary Structure ◽  
Insertion Site ◽  
Large Body ◽  
P Element ◽  
Wild Type ◽  
Subtle Difference ◽  
Pronounced Difference ◽  
Internal Repeat ◽  
Mutant Phenotypes

Abstract We report here the isolation of a new P-element-induced allele of the vestigial locus vg2a33, the molecular characterization of which allows us to propose a unifying explanation of the phenotypes of the large number of vestigial P-element alleles that now exists. The first P-element allele of vestigial to be isolated was vg21, which results in a very weak mutant wing phenotype that is suppressed in the P cytotype. By destabilizing vg2a33 in a dysgenic cross, we isolated the vg2a33 allele, which exhibits a moderate mutant wing phenotype and is not suppressed by the P cytotype. The new allele is characterized by a 46-bp deletion that removes the 3′-proximal copy of the 11-bp internal repeat from the P element of vg21. To understand how this subtle difference between the two alleles leads to a rather pronounced difference in their phenotypes, we mapped both the vg and P-element transcription units present in wild type and mutants. Using both 5′-RACE and S1 protection, we found that P-element transcription is initiated 19 bp farther upstream than previously thought. Using primer extension, the start of vg transcription was determined to lie 435 bp upstream of the longest cDNA recovered to date and upstream of the P-element insertion site. Our discovery that the P element is situated within the first vg exon has prompted a reassessment of the large body of genetic data on a series of alleles derived from vg21. Our current hypothesis to explain the degree of variation in the mutant phenotypes and their response to the P repressor invokes a critical RNA secondary structure in the vg transcript, the formation of which is hindered by a readthrough transcript initiated at the P-element promoter.

scholarly journals Mutator-Suppressible Alleles of rough sheath1 and liguleless3 in Maize Reveal Multiple Mechanisms for Suppression

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 437-446 ◽  
Author(s):  
Lisa Girard ◽  
Michael Freeling
Keyword(s):  
Untranslated Region ◽  
Mutant Allele ◽  
Negative Regulation ◽  
Wild Type ◽  
Knox Gene ◽  
Transcript Accumulation ◽  
Mu Suppression ◽  
Different Types ◽  
Rna Blot Analysis

Abstract Insertions of Mutator transposons into maize genes can generate suppressible alleles. Mu suppression is when, in the absence of Mu activity, the phenotype of a mutant allele reverts to that of its progenitor. Here we present the characterization of five dominant Mu-suppressible alleles of the knox (knotted1-like homeobox) genes liguleless3 and rough sheath1, which exhibit neomorphic phenotypes in the leaves. RNA blot analysis suggests that Mu suppression affects only the neomorphic aspect of the allele, not the wild-type aspect. Additionally, Mu suppression appears to be exerting its effects at the level of transcription or transcript accumulation. We show that truncated transcripts are produced by three alleles, implying a mechanism for Mu suppression of 5′ untranslated region insertion alleles distinct from that which has been described previously. Additionally, it is found that Mu suppression can be caused by at least three different types of Mutator elements. Evidence presented here suggests that whether an allele is suppressible or not may depend upon the site of insertion. We cite previous work on the knox gene kn1, and discuss our results in the context of interactions between Mu-encoded products and the inherently negative regulation of neomorphic liguleless3 and rough sheath1 transcription.

scholarly journals Insights into neutralizing antibody responses in individuals exposed to SARS-CoV-2 in Chile

2021 ◽  
Vol 7 (7) ◽  
pp. eabe6855 ◽  
Author(s):  
Carolina Beltrán-Pavez ◽  
Sebastián Riquelme-Barrios ◽  
Aarón Oyarzún-Arrau ◽  
Aracelly Gaete-Argel ◽  
Roxana González-Stegmaier ◽  
...  
Keyword(s):  
General Population ◽  
Local Level ◽  
Neutralizing Antibody ◽  
Host Immunity ◽  
Antibody Responses ◽  
Wild Type ◽  
Neutralization Activity ◽  
Future Studies

Chile has one of the worst numbers worldwide in terms of SARS-CoV-2 positive cases and COVID-19–related deaths per million inhabitants; thus, characterization of neutralizing antibody (NAb) responses in the general population is critical to understanding of immunity at the local level. Given our inability to perform massive classical neutralization assays due to the scarce availability of BSL-3 facilities in the country, we developed and fully characterized an HIV-based SARS-CoV-2 pseudotype, which was used in a 96-well plate format to investigate NAb responses in samples from individuals exposed to SARS-CoV-2 or treated with convalescent plasma. We also identified samples with decreased or enhanced neutralization activity against the D614G spike variant compared with the wild type, indicating the relevance of this variant in host immunity. The data presented here represent the first insights into NAb responses in individuals from Chile, serving as a guide for future studies in the country.

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