ORCID Profile
0000-0002-1983-6735
Current Organisations
University of Leeds
,
Amirkabir University of Technology
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Publisher: Elsevier BV
Date: 12-2019
Publisher: Wiley
Date: 28-11-2018
DOI: 10.1002/PAT.4480
Publisher: Public Library of Science (PLoS)
Date: 28-11-2022
DOI: 10.1371/JOURNAL.PNTD.0010833
Abstract: Tsetse flies ( Glossina spp.) feed exclusively on vertebrate blood. After a blood meal, the enteric endosymbiont Sodalis glossinidius is exposed to various environmental stressors including high levels of heme. To investigate how S . glossinidius morsitans ( Sgm ), the Sodalis subspecies that resides within the gut of G . morsitans , tolerates the heme-induced oxidative environment of tsetse’s midgut, we used RNAseq to identify bacterial genes that are differentially expressed in cells cultured in high versus lower heme environments. Our analysis identified 436 genes that were significantly differentially expressed ( or 2-fold) in the presence of high heme [219 heme-induced genes (HIGs) and 217 heme-repressed genes (HRGs)]. HIGs were enriched in Gene Ontology (GO) terms related to regulation of a variety of biological functions, including gene expression and metabolic processes. We observed that 11 out of 13 Sgm genes that were heme regulated in vitro were similarly regulated in bacteria that resided within tsetse’s midgut 24 hr (high heme environment) and 96 hr (low heme environment) after the flies had consumed a blood meal. We used intron mutagenesis to make insertion mutations in 12 Sgm HIGs and observed no significant change in growth in vitro in any of the mutant strains in high versus low heme conditions. However, Sgm strains that carried mutations in genes encoding a putative undefined phosphotransferase sugar (PTS) system component (SG2427), fucose transporter (SG0182), bacterioferritin (SG2280), and a DNA-binding protein (SGP1-0002), presented growth and/or survival defects in tsetse midguts as compared to normal Sgm . These findings suggest that the uptake up of sugars and storage of iron represent strategies that Sgm employs to successfully reside within the high heme environment of its tsetse host’s midgut. Our results are of epidemiological relevance, as many hematophagous arthropods house gut-associated bacteria that mediate their host’s competency as a vector of disease-causing pathogens.
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.MSEC.2015.06.044
Abstract: A simple, green and low cost method based on Tollens' reagent is presented to synthesize a nano-conductive silver layer on nylon 6 fabric. The nylon fabric was first treated with potassium permanganate to oxidize fabric surface and thereby, increasing the number of assembled particles on the fabric surface. SEM images indicated distribution of silver nanoparticles on the fabric surface and formation of nanolayer on the fiber surface. EDX and XRD patterns confirmed assembling silver nanoparticles on the nylon fibers. The treated fabrics displayed a very low electrical resistivity i.e. 4.5Ω/sq. Furthermore, the fabric color was indicated by a reflectance spectrophotometer in order to study the effects of the synthesized nanoparticles on the fabric color. It is also indicated that oxidation process has no significant influence on the mechanical properties of the fabric, and nano-treatment revenged the negative effect of oxidation of nylon fabric. Moreover, silver nanoparticles imparted reasonable antibacterial properties to the fabric against Staphylococcus aureus.
Publisher: Informa UK Limited
Date: 04-2011
Publisher: Springer Science and Business Media LLC
Date: 07-2007
DOI: 10.1007/BF02875827
Publisher: Elsevier BV
Date: 02-2011
Publisher: Elsevier BV
Date: 06-2011
DOI: 10.1016/J.JPHOTOBIOL.2011.03.009
Abstract: In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO(2) as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO(2) nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO(2) on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM).
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2022
DOI: 10.1101/2022.09.22.508973
Abstract: Tsetse flies ( Glossina spp.) feed exclusively on vertebrate blood. After a blood meal, the enteric endosymbiont Sodalis glossinidius is exposed to various environmental stressors including high levels of heme. To investigate how S. glossinidius morsitans (Sgm , the Sodalis subspecies that resides within the gut of G. morsitans ) tolerates the heme-induced oxidative environment of tsetse’s midgut, we used RNAseq to identify bacterial genes that are differentially expressed in cells cultured in high versus lower heme environments. Our analysis identified 436 genes that were significantly differentially expressed ( or 2-fold) in the presence of high heme [219 heme-induced genes (HIGs) and 217 heme-repressed genes (HRGs)]. HIGs were enriched in Gene Ontology (GO) terms related to regulation of a variety of biological functions, including gene expression and metabolic processes. We observed that 11 out of 13 Sgm genes that were heme regulated in vitro were similarly regulated in bacteria that resided within tsetse’s midgut 24 hr (high heme environment) and 96 hr (low heme environment) after the flies had consumed a blood meal. We used intron mutagenesis to make insertion mutations in 12 Sgm HIGs and observed no significant change in growth in vitro in any of the mutant strains in high versus low heme conditions. However, Sgm strains that carried mutations in genes encoding a putative undefined phosphotransferase sugar (PTS) system component (SG2427), fucose transporter (SG0182), bacterioferritin (SG2280), and a DNA-binding protein (SGP1-0002) presented growth and/or survival defects in tsetse midguts as compared to normal Sgm . These findings suggest that the uptake up of sugars and storage of iron represent strategies that Sgm employs to successfully reside within the high heme environment of its tsetse host’s midgut. Our results are of epidemiological relevance, as many hematophagous arthropods house gut-associated bacteria that mediate their host’s competency as a vector of disease-causing pathogens. Tsetse flies feed exclusively on vertebrate blood. This nutrient source contains large quantities of heme, which can be toxic to the fly’s associated microorganisms. We investigated the genetic mechanisms that underlie the ability of the bacterial endosymbiont, Sodalis glossinidius , to successfully reside within tsetse’s heme-rich midgut. Exposure of cultured S. glossinidius to high levels of heme induced changes in the expression of genes that encode proteins involved in transcription, replication and repair of DNA, inorganic ion transport, and carbohydrate transport and metabolism processes. Changes in the expression of several of these same S. glossinidius genes also occurred within tsetse’s midgut following exposure to a blood meal. S. glossinidius genetically engineered to present mutations in several of these heme regulated genes were unable to successfully colonize tsetse’s gut. Our results provide insight into how bacteria that live in the gut of blood feeding arthropods mitigate the toxic effects of excessive heme. This information is of epidemiological relevance, as many of these bacteria influence their host’s ability to transmit disease pathogens that cause disease in humans and domesticated animals.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Wiley
Date: 11-04-2011
DOI: 10.1002/APP.33979
Publisher: Wiley
Date: 12-04-2011
DOI: 10.1002/APP.33858
Publisher: Springer Science and Business Media LLC
Date: 10-2010
Publisher: Wiley
Date: 03-2010
DOI: 10.1111/J.1751-1097.2009.00680.X
Abstract: Wool is the most important animal fiber used in textile industries, but its photostability is very low. Scientists have searched for new ways to increase the photostability of wool. As TiO(2) nano particles have features suitable for new applications, the UV-blocking power of nano TiO(2) may be used for protecting fabrics against UV rays. Treatment of wool with TiO(2) can be effective for controlling photodegradation. This study focused on protecting wool fabric against UV rays using nano TiO(2). To this end, oxidized and raw wool were treated with citric acid as the cross-linking agent and different concentrations of nano TiO(2). The whiteness and yellowness of wool fabric s les were reported. XRD patterns proved the existence of TiO(2) nano-particles on the wool surface. Finally, the results revealed that nano TiO(2) is a suitable UV absorber on wool fabric and its effect depends on concentration.
Publisher: Elsevier BV
Date: 12-2011
Location: United Kingdom of Great Britain and Northern Ireland
Location: Iran (Islamic Republic of)
No related grants have been discovered for Majid Montazer.