scholarly journals Elucidation of the Antibacterial Mechanism of the Curvularia Haloperoxidase System by DNA Microarray Profiling

2004 ◽  
Vol 70 (3) ◽  
pp. 1749-1757 ◽  
Author(s):  
Eva H. Hansen ◽  
Mark A. Schembri ◽  
Per Klemm ◽  
Thomas Sch�fer ◽  
S�ren Molin ◽  
...  
Keyword(s):  
Dna Microarray ◽  
Dna Microarrays ◽  
Enzyme System ◽  
E Coli ◽  
Expression Of Genes ◽  
Knockout Mutants ◽  
Microarray Profiling ◽  
Genes Encoding ◽  
Cpx Pathway ◽  
Shock Proteins

ABSTRACT A novel antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of elucidating its mechanism of antibacterial action. Escherichia coli strain MG1655 was stressed with sublethal concentrations of the enzyme system, causing a temporary arrest of growth. The expression of genes altered upon exposure to the Curvularia haloperoxidase system was analyzed by using DNA microarrays. Only a limited number of genes were involved in the response to the Curvularia haloperoxidase system. Among the induced genes were the ibpA and ibpB genes encoding small heat shock proteins, a gene cluster of six genes (b0301-b0306) of unknown function, and finally, cpxP, a member of the Cpx pathway. Knockout mutants were constructed with deletions in b0301-b0306, cpxP, and cpxARP, respectively. Only the mutant lacking cpxARP was significantly more sensitive to the enzyme system than was the wild type. Our results demonstrate that DNA microarray technology cannot be used as the only technique to investigate the mechanisms of action of new antimicrobial compounds. However, by combining DNA microarray analysis with the subsequent creation of knockout mutants, we were able to pinpoint one of the specific responses of E. coli—namely, the Cpx pathway, which is important for managing the stress response from the Curvularia haloperoxidase system.

scholarly journals Improved Squalene Production via Modulation of the Methylerythritol 4-Phosphate Pathway and Heterologous Expression of Genes from Streptomyces peucetius ATCC 27952 in Escherichia coli

2009 ◽  
Vol 75 (22) ◽  
pp. 7291-7293 ◽  
Author(s):  
Gopal Prasad Ghimire ◽  
Hei Chan Lee ◽  
Jae Kyung Sohng
Keyword(s):  
Escherichia Coli ◽  
Heterologous Expression ◽  
Farnesyl Diphosphate ◽  
Farnesyl Diphosphate Synthase ◽  
Isopentenyl Diphosphate ◽  
Isopentenyl Diphosphate Isomerase ◽  
Streptomyces Peucetius ◽  
E Coli ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACT Putative hopanoid genes from Streptomyces peucetius were introduced into Escherichia coli to improve the production of squalene, an industrially important compound. High expression of hopA and hopB (encoding squalene/phytoene synthases) together with hopD (encoding farnesyl diphosphate synthase) yielded 4.1 mg/liter of squalene. This level was elevated to 11.8 mg/liter when there was also increased expression of dxs and idi, E. coli genes encoding 1-deoxy-d-xylulose 5-phosphate synthase and isopentenyl diphosphate isomerase.

scholarly journals Gastric Transcription Profile of Helicobacter pylori Infection in the Rhesus Macaque

2004 ◽  
Vol 72 (9) ◽  
pp. 5216-5226 ◽  
Author(s):  
Jennifer L. Huff ◽  
Lori M. Hansen ◽  
Jay V. Solnick
Keyword(s):  
Helicobacter Pylori ◽  
Rhesus Macaque ◽  
Dna Microarrays ◽  
Transcription Profile ◽  
Ulcer Disease ◽  
Expression Of Genes ◽  
Relevant Animal Model ◽  
Cell Growth And Differentiation ◽  
H Pylori ◽  
Shock Proteins

ABSTRACT Infection with Helicobacter pylori is usually asymptomatic but sometimes progresses to peptic ulcer disease or gastric adenocarcinoma. The development of disease involves both host and bacterial factors. In order to better understand host factors in pathogenesis, we studied the gastric transcription profile of H. pylori infection in the rhesus macaque by using DNA microarrays. Significant changes were found in the expression of genes important for innate immunity, chemokines and cytokines, cell growth and differentiation, apoptosis, structural proteins, and signal transduction and transcription factors. This broad transcription profile demonstrated expected up-regulation of cell structural elements and the host inflammatory and immune response, as well as the novel finding of down-regulation of heat shock proteins. These results provide a unique view of acute H. pylori infection in a relevant animal model system and will direct future studies regarding the host response to H. pylori infection.

scholarly journals 308 IMMUNOLOCALIZATION AND GENE CLONING OF ZEATIN OXYLOSYLTRANSFERASE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 474d-474
Author(s):  
Ruth C. Martin ◽  
Machteld C. Mok ◽  
David W.S. Mok
Keyword(s):  
Cdna Libraries ◽  
E Coli ◽  
Baculovirus Expression ◽  
Expression Of Genes ◽  
Immature Seeds ◽  
Tissue Print ◽  
Genes Encoding ◽  
In Vitro Systems ◽  
Transformation Systems

Cytokinins are widely used in tissue culture and transformation systems; however, little is known of their mode of action or the mechanisms regulating their levels in plant tissues. We are studying enzymes responsible for the metabolism of zeatin in immature seeds of Phaseolus. Selective expression of genes encoding such enzymes may regulate the level of active cytokinins during seed development as well as in in vitro systems. A zeatin O-xylosyltransferase, which mediates the formation of O-xylosylzeatin from trans-zeatin and UDP-xylose, has been isolated and monoclonal antibodies specific to the enzyme have been produced. Tissue print analyses demonstrated that the enzyme is primarily localized in the endosperm. ln situ localization and EM studies indicated that the enzyme is present in the cytoplasm and the nucleus. cDNA libraries were constructed from immature seed mRNA and immunopositive clones were selected. The products of these clones are being analyzed in E. coli and baculovirus expression systems.

Analysis of Gene Expression in Response to Copper Stress in Acidithiobacillus ferrooxidans Strain D2, Isolated from a Copper Bioleaching Operation

2013 ◽  
Vol 825 ◽  
pp. 157-161 ◽  
Author(s):  
Camila N. Salazar ◽  
Mauricio Acosta ◽  
Pedro A. Galleguillos ◽  
Amir Shmaryahu ◽  
Raquel Quatrini ◽  
...  
Keyword(s):  
Stress Response ◽  
Acidithiobacillus Ferrooxidans ◽  
Dna Microarrays ◽  
Copper Stress ◽  
Molecular Response ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
High Concentrations ◽  
P Type ◽  
Upregulated Genes

Acidithiobacillus ferrooxidans strain D2 was isolated from a copper bioleaching operation in Atacama Desert, Chile. Copper is widely used as cofactor in proteins but high concentrations of copper are toxic. Cells require certain mechanisms to maintain the copper homeostasis and avoid toxic effects of high intracellular concentration. The molecular response of A. ferrooxidans strain D2 grown in the presence/absence of copper was examined using a A. ferrooxidans whole-genome DNA microarrays. Roughly 23% of 3,147 genes represented on the microarray were differentially expressed; about 9% of them were upregulated in the presence of copper. Among the upregulated genes, those encoding for the copper efflux protein (CusA) and for the copper-translocating P-type ATPase (CopA) were upregulated. The expression of genes encoding proteins related to iron transport was repressed. Similarly, genes related with assimilative metabolism of sulfur (L-cysteine biosynthesis) cysB, cysJ, cysI, CysD-2 and cysN were upregulated. Our results show that when A. ferrooxidans strain D2 was challenged with high copper concentrations, genes related to copper stress response were upregulated as well as others that have not been reported to be related to that mechanism. In addition, some genes related to other metabolic pathways were repressed, probably because of the energy cost of the stress response.

Establishment of tolerance to commensal bacteria requires a complex microbiota and is accompanied by decreased intestinal chemokine expression

2012 ◽  
Vol 302 (1) ◽  
pp. G55-G65 ◽  
Author(s):  
L. N. Fink ◽  
S. B. Metzdorff ◽  
L. H. Zeuthen ◽  
C. Nellemann ◽  
M. B. Kristensen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lymph Nodes ◽  
Ex Vivo ◽  
Gene Expression Pattern ◽  
Mesenteric Lymph Nodes ◽  
Microbial Detection ◽  
E Coli ◽  
Germ Free ◽  
Expression Of Genes ◽  
Genes Encoding

Intricate regulation of tolerance to the intestinal commensal microbiota acquired at birth is critical. We hypothesized that epithelial cell tolerance toward early gram-positive and gram-negative colonizing bacteria is established immediately after birth, as has previously been shown for endotoxin. Gene expression in the intestine of mouse pups born to dams that were either colonized with a conventional microbiota or monocolonized ( Lactobacillus acidophilus or Eschericia coli ) or germ free was examined on day 1 and day 6 after birth. Intestinal epithelial cells from all groups of pups were stimulated ex vivo with L. acidophilus and E. coli to assess tolerance establishment. Intestine from pups exposed to a conventional microbiota displayed lower expression of Ccl2, Ccl3, Cxcl1, Cxcl2, and Tslp than germ-free mice, whereas genes encoding proteins in Toll-like receptor signaling pathways and cytokines were upregulated. When comparing pups on day 1 and day 6 after birth, a specific change in gene expression pattern was evident in all groups of mice. Tolerance to ex vivo stimulation with E. coli was only established in conventional animals. Colonization of the intestine was reflected in the spleen displaying downregulation of Cxcl2 compared with germ-free animals on day 1 after birth. Colonization reduced the expression of genes involved in antigen presentation in the intestine-draining mesenteric lymph nodes, but not in the popliteal lymph nodes, as evidenced by gene expression on day 23 after birth. We propose that microbial detection systems in the intestine are upregulated by colonization with a diverse microbiota, whereas expression of proinflammatory chemokines is reduced to avoid excess recruitment of immune cells to the maturing intestine.

scholarly journals Cloning and expression of genes encoding heat shock proteins in Liriomyza trifolii and comparison with two congener leafminer species

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0181355 ◽  
Author(s):  
Ya-Wen Chang ◽  
Jing-Yun Chen ◽  
Ming-Xing Lu ◽  
Yuan Gao ◽  
Zi-Hua Tian ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Cloning And Expression ◽  
Liriomyza Trifolii ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Shock Proteins

DNA Microarray-Based Genomic Characterization of the Pathotypes of Escherichia coli O26, O45, O103, O111, and O145 Isolated from Feces of Feedlot Cattle†

2019 ◽  
Vol 82 (3) ◽  
pp. 395-404 ◽  
Author(s):  
PRAGATHI B. SHRIDHAR ◽  
ISHA R. PATEL ◽  
JAYANTHI GANGIREDLA ◽  
LANCE W. NOLL ◽  
XIAORONG SHI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Microarray ◽  
Virulence Genes ◽  
Feedlot Cattle ◽  
Clinical Strains ◽  
E Coli ◽  
Type Iii ◽  
Virulence Potential ◽  
Genes Encoding ◽  
Secretory System

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 serogroups, are responsible for more than 70% of human non-O157 STEC infections in North America. Cattle harbor non-O157 strains in the hindgut and shed them in the feces. The objective of this study was to use the U.S. Food and Drug Administration (FDA) E. coli identification (ECID) DNA microarray to identify the serotype, assess the virulence potential of each, and determine the phylogenetic relationships among five of the six non-O157 E. coli serogroups isolated from feedlot cattle feces. Forty-four strains of STEC, enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), or putative nonpathotype E. coli (NPEC) of cattle origin and five human clinical strains of EHEC were assayed with the FDA-ECID DNA microarray. The cattle strains harbored diverse flagellar genes. The bovine and human strains belonging to serogroups O26, O45, and O103 carried stx1 only, O111 carried both stx1 and stx2, and O145 carried either stx1 or stx2. The strains were also positive for various subtypes of intimin and other adhesins (IrgA homologue adhesin, long polar fimbriae, mannose-specific adhesin, and curli). Both human and cattle strains were positive for LEE-encoded type III secretory system genes and non–LEE-encoded effector genes. SplitsTree4, a program used to determine the phylogenetic relationship among the strains, revealed that the strains within each serogroup clustered according to their pathotype. In addition to genes encoding Shiga toxins, bovine non-O157 E. coli strains possessed other major virulence genes, including those for adhesins, type III secretory system proteins, and plasmid-borne virulence genes, similar to human clinical strains. Because virulence factors encoded by these genes are involved in the pathogenesis of various pathotypes of E. coli, the bovine non-O157 strains could cause human illness. The FDA-ECID DNA microarray assay rapidly provided a profile of the virulence genes for assessment of the virulence potential of each strain.

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