scholarly journals Involvement of the oscA gene in the sulphur starvation response and in Cr(VI) resistance in Pseudomonas corrugata 28

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Carlo Viti ◽  
Francesca Decorosi ◽  
Annalisa Mini ◽  
Enrico Tatti ◽  
Luciana Giovannetti
Keyword(s):  
Insertional Mutagenesis ◽  
Sole Source ◽  
Transcriptional Unit ◽  
Phenotype Microarray ◽  
Pseudomonas Corrugata ◽  
Periplasmic Binding Protein ◽  
Sensitive Mutant ◽  
Starvation Response ◽  
Complementation Experiment ◽  
Chromate Exposure

Pseudomonas corrugata 28 is a Cr(VI)-hyper-resistant bacterium. A Cr(VI)-sensitive mutant was obtained by insertional mutagenesis using EZ-Tn5 <R6Kγori/KAN-2>Tnp. The mutant strain was impaired in a gene, here named oscA (organosulphur compounds), which encoded a hypothetical small protein of unknown function. The gene was located upstream of a gene cluster that encodes the components of the sulphate ABC transporter, and it formed a transcriptional unit with sbp, which encoded the periplasmic binding protein of the transporter. The oscA–sbp transcriptional unit was strongly and quickly overexpressed after chromate exposure, suggesting the involvement of oscA in chromate resistance, which was further confirmed by means of a complementation experiment. Phenotype MicroArray (PM) analysis made it possible to assay 1536 phenotypes and also indicated that the oscA gene was involved in the utilization of organosulphur compounds as a sole source of sulphur. This is believed to be the first evidence that oscA plays a role in activating a sulphur starvation response, which is required to cope with oxidative stress induced by chromate.

scholarly journals Identification and Characterization of thecps Locus of Streptococcus suis Serotype 2: the Capsule Protects against Phagocytosis and Is an Important Virulence Factor

1999 ◽  
Vol 67 (4) ◽  
pp. 1750-1756 ◽  
Author(s):  
Hilde E. Smith ◽  
Marloes Damman ◽  
Joeke van der Velde ◽  
Frans Wagenaar ◽  
Henk J. Wisselink ◽  
...  
Keyword(s):  
Insertional Mutagenesis ◽  
Capsular Polysaccharide ◽  
Streptococcus Suis ◽  
Open Reading Frames ◽  
Transcriptional Unit ◽  
Polysaccharide Biosynthesis ◽  
Capsule Production ◽  
Important Virulence Factor ◽  
Isogenic Mutants

ABSTRACT To study the role of the capsule of Streptococcus suisserotype 2 in virulence, we generated two isogenic mutants disturbed in capsule production. For that purpose, we first cloned and characterized a major part of the capsular polysaccharide biosynthesis (cps) locus of S. suis serotype 2. Based on the established sequence, 14 open reading frames (ORFs), designated Orf2Z, Orf2Y, Orf2X, and Cps2A to Cps2K, were identified. Twelve ORFs belonged to a single transcriptional unit. The gene products of 11 of these ORFs showed similarity to proteins involved in polysaccharide biosynthesis of other gram-positive microorganisms. Nonencapsulated isogenic mutants were generated in the cps2B and cps2EF genes by insertional mutagenesis. In contrast to the wild-type S. suis serotype 2 strain, the nonencapsulated strains were highly sensitive to ingestion by porcine alveolar lung macrophages in vitro. More importantly, the nonencapsulated mutant strains were completely avirulent in young germfree pigs after intranasal inoculation. These observations indicate that the capsule of S. suis serotype 2 plays an essential role in the pathogenesis of S. suisserotype 2 infections.

scholarly journals Phase Variation of Hemoglobin Utilization inNeisseria gonorrhoeae

1998 ◽  
Vol 66 (3) ◽  
pp. 987-993 ◽  
Author(s):  
Ching-Ju Chen ◽  
Christopher Elkins ◽  
P. Frederick Sparling
Keyword(s):  
Insertional Mutagenesis ◽  
Outer Membrane Proteins ◽  
Phase Variation ◽  
Sole Source ◽  
Hemoglobin Binding ◽  
Minor Population ◽  
Sequence Encoding ◽  
A Minor ◽  
Phase Variants ◽  
Do So

ABSTRACT Most Neisseria gonorrhoeae isolates are unable to use human hemoglobin as the sole source of iron for growth (Hgb−), but a minor population is able to do so (Hgb+). This minor population grows luxuriously on hemoglobin, expresses two outer membrane proteins of 42 kDa (HpuA) and 89 kDa (HpuB), and binds hemoglobin under iron-stressed conditions. In addition to the previously reported HpuB, we identified and characterized HpuA, which is encoded by the gene hpuA, located immediately upstream of hpuB. Expression of both proteins was found to be controlled at the translational level by frameshift mutations in a run of guanine residues within thehpuA sequence encoding the mature HpuA protein. The “on-phase” hemoglobin-utilizing variants contained 10 G’s, while the “off-phase” variants contained 9 G’s. InsertionalhpuB mutants of FA19 Hgb+ and FA1090 Hgb+ no longer expressed HpuB but still produced HpuA. A polar insertional mutation of the upstream hpuA gene in FA1090 Hgb+ eliminated production of both HpuA and HpuB, whereas a nonpolar insertional mutant expressed HpuB only. Insertional mutagenesis of either hpuA or hpuB or both substantially decreased the hemoglobin binding ability of the FA1090 Hgb+ variant and prevented growth on hemoglobin plates. Therefore, both HpuA and HpuB were required for the utilization of hemoglobin for growth.

Retroviral insertional mutagenesis in murine mammary cancer

1985 ◽  
Vol 226 (1242) ◽  
pp. 3-13 ◽  
Keyword(s):  
Insertional Mutagenesis ◽  
Insertion Site ◽  
Latency Period ◽  
Transcriptional Unit ◽  
Chromosomal Dna ◽  
Transcriptional Enhancer ◽  
Detailed Structural Analysis ◽  
Mammary Tumours ◽  
Long Latency ◽  
Protein Encoding

We are attempting to identify cellular oncogenes activated in mammary tumours by using the mouse mammary tumour virus (MMTV) as an insertional mutagen. MMTV, a retrovirus lacking a host cell-derived viral oncogene, induces adenocarcinomas of the mammary gland after a long latency period. The tumours are clonal outgrowths of cells carrying one or more integrated MMTV proviral copies. We have cloned an integrated MMTV provirus with its adjacent chromosomal DNA and we have established that the insertion site was part of a domain of the mouse genome in which MMTV proviruses are inserted in many different tumours. A gene within this domain, called int -1 is transcriptionally activated as a consequence of proviral integration. We have proposed that int -1 is a cellular oncogene for mammary tumours. Proviral activation of int -1 occurs in cis , over distances of up to 10 kilobases and is presumably caused by the transcriptional enhancer present on the MMTV long terminal repeat. The putative int -1 mammary oncogene has been subjected to a detailed structural analysis by S1 mapping and DNA sequencing. It encodes a protein that is highly conserved between mouse and man. The protein encoding domain of the gene is distributed over four exons which are demarcated by the insertion sites of MMTV proviruses found in mammary tumours. Some insertions, however, are found in the transcriptional unit of int -1, but these insertions do not disrupt the protein encoding domain of the gene.

Childhood adversity studies as an antidote to the predominance of neo-liberal thinking in the field of mental health

2020 ◽  
Vol 29 (4) ◽  
pp. 556-563
Author(s):  
Adam Burley
Keyword(s):  
Mental Health ◽  
Childhood Adversity ◽  
Sole Source ◽  
Point Of View ◽  
Early Adversity ◽  
Potential Impact ◽  
The Individual

This is a personal and reflective piece written from a clinician's point of view on the influence that the developing awareness around the consequences of childhood adversity has had upon the discussions, thinking and practice across the areas in which they are working. It seeks to argue that the increased understanding and recognition of the potential impact of early adversity can not only enhance and deepen the understanding of an individual's difficulties, but can serve to inform how services respond in a way that takes account of this. It suggests that the research and literature on childhood adversity can offer a route map away from a model of mental health that focuses predominantly on the individual as the sole source of interest.

Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Pseudomonas aeruginosa from Clinical Isolates

2020 ◽  
Vol 21 (14) ◽  
pp. 1539-1550
Author(s):  
Nur S. Ismail ◽  
Suresh K. Subbiah ◽  
Niazlin M. Taib
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbon Sources ◽  
Anaerobic Respiration ◽  
Regulatory System ◽  
Negative Control ◽  
High Morbidity ◽  
Metabolic Profiles ◽  
Phenotype Microarray ◽  
Diverse Environment ◽  
Phenotype Microarrays

Background: This is the fastest work in obtaining the metabolic profiles of Pseudomonas aeruginosa in order to combat the infection diseases which leads to high morbidity and mortality rates. Pseudomonas aeruginosa is a high versatility of gram-negative bacteria that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism and regulatory system, ensure the survival of this microorganism in the diverse environment condition. Determination of differences in carbon sources utilization among biofilm and non-biofilm of Pseudomonas aeruginosa provides a platform in understanding the metabolic activity of the microorganism. Methods: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog). Results and Discussion: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid. Conclusion: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.

Sign in / Sign up

Export Citation Format

Share Document