Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance staphylococcus aureus (CA-MRSA) strains that cause severe infection among the healthy individual with no predisposing factor further exacerbate the conditions.
CA-MRSA strains produce a vast array of virulence factors that are controlled by a complex network of global virulence regulators, and they make this pathogen more successful compared to other MRSA strains. In previous study, we have shown that the msaABCR is a new four gene operon that globally regulates virulence and biofilm development in S. aureus. Also we have shown that this operon regulates the expression of some well-characterized global regulators like sarA and agrA which play vital roles in S. aureus pathogenesis. In order to study the role of individual gene in this operon, we deleted the first gene (msaA) of msaABCR operon and found that msaA gene plays an opposing role in the regulation of msaABCR operon in terms of regulation of sarA, extracellular protease production, and biofilm formation. Deletion of msaA led to the over-expression of sarA, decreased protease production, and increased biofilm formation, which is in contrast to msaC and msaABCR deletion mutant which down regulates the expression of sarA, increases the production of protease, and decreases biofilm formation, which suggests a regulatory role for msaA gene in regulation of msaABCR operon.
","abstract_html":"<p>Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to <em>S. aureus</em>. Treating <em>S. aureus</em> infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance staphylococcus aureus (CA-MRSA) strains that cause severe infection among the healthy individual with no predisposing factor further exacerbate the conditions.</p> <p>CA-MRSA strains produce a vast array of virulence factors that are controlled by a complex network of global virulence regulators, and they make this pathogen more successful compared to other MRSA strains. In previous study, we have shown that the <em>msaABCR</em> is a new four gene operon that globally regulates virulence and biofilm development in <em>S. aureus</em>. Also we have shown that this operon regulates the expression of some well-characterized global regulators like <em>sarA</em> and <em>agrA</em> which play vital roles in <em>S. aureus</em> pathogenesis. In order to study the role of individual gene in this operon, we deleted the first gene (<em>msaA</em>) of <em>msaABCR</em> operon and found that <em>msaA</em> gene plays an opposing role in the regulation of <em>msaABCR</em> operon in terms of regulation of <em>sarA</em>, extracellular protease production, and biofilm formation. Deletion of <em>msaA</em> led to the over-expression of <em>sarA</em>, decreased protease production, and increased biofilm formation, which is in contrast to <em>msaC</em> and <em>msaABCR</em> deletion mutant which down regulates the expression of <em>sarA</em>, increases the production of protease, and decreases biofilm formation, which suggests a regulatory role for <em>msaA</em> gene in regulation of <em>msaABCR</em> operon.</p>","abstract_has_math":false,"creators":["Alzuway, Ahmed"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":"Biological Sciences","degree_department":null,"school":null,"contributors":["Mohamed O. Elasri","Glenmore Shearer","Shahid Karim"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-08-01T07:00:00Z","date_published":"2014-08-01T07:00:00Z","updated_at":"2026-07-24T05:44:27Z","subjects":["Staphylococcus aureus","msaA","msaABCR operon","biofilm","virulence factors","global regulator","Biology","Cell and Developmental Biology","Cell Biology","Developmental Biology","Life Sciences"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/56","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mohamed O. 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Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance staphylococcus aureus (CA-MRSA) strains that cause severe infection among the healthy individual with no predisposing factor further exacerbate the conditions.
CA-MRSA strains produce a vast array of virulence factors that are controlled by a complex network of global virulence regulators, and they make this pathogen more successful compared to other MRSA strains. In previous study, we have shown that the msaABCR is a new four gene operon that globally regulates virulence and biofilm development in S. aureus. Also we have shown that this operon regulates the expression of some well-characterized global regulators like sarA and agrA which play vital roles in S. aureus pathogenesis. In order to study the role of individual gene in this operon, we deleted the first gene (msaA) of msaABCR operon and found that msaA gene plays an opposing role in the regulation of msaABCR operon in terms of regulation of sarA, extracellular protease production, and biofilm formation. Deletion of msaA led to the over-expression of sarA, decreased protease production, and increased biofilm formation, which is in contrast to msaC and msaABCR deletion mutant which down regulates the expression of sarA, increases the production of protease, and decreases biofilm formation, which suggests a regulatory role for msaA gene in regulation of msaABCR operon.
"]},{"key":"dc:title","label":"Title","values":["Role of msaA Gene in Regulation of the msaABCR Operon and Biofilm Development in Staphylococcus aureus"]}]}],"canonical_facts":{"dc:contributor":["Mohamed O. Elasri","Glenmore Shearer","Shahid Karim"],"dc:creator":["Alzuway, Ahmed"],"dc:date.available":["2014-08-01T07:00:00Z"],"dc:description.abstract":["Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance staphylococcus aureus (CA-MRSA) strains that cause severe infection among the healthy individual with no predisposing factor further exacerbate the conditions.
CA-MRSA strains produce a vast array of virulence factors that are controlled by a complex network of global virulence regulators, and they make this pathogen more successful compared to other MRSA strains. In previous study, we have shown that the msaABCR is a new four gene operon that globally regulates virulence and biofilm development in S. aureus. Also we have shown that this operon regulates the expression of some well-characterized global regulators like sarA and agrA which play vital roles in S. aureus pathogenesis. In order to study the role of individual gene in this operon, we deleted the first gene (msaA) of msaABCR operon and found that msaA gene plays an opposing role in the regulation of msaABCR operon in terms of regulation of sarA, extracellular protease production, and biofilm formation. Deletion of msaA led to the over-expression of sarA, decreased protease production, and increased biofilm formation, which is in contrast to msaC and msaABCR deletion mutant which down regulates the expression of sarA, increases the production of protease, and decreases biofilm formation, which suggests a regulatory role for msaA gene in regulation of msaABCR operon.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/56"],"dc:subject":["Staphylococcus aureus","msaA","msaABCR operon","biofilm","virulence factors","global regulator","Biology","Cell and Developmental Biology","Cell Biology","Developmental Biology","Life Sciences"],"dc:title":["Role of msaA Gene in Regulation of the msaABCR Operon and Biofilm Development in Staphylococcus aureus"],"thesis:degree_discipline":["Biological Sciences"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:44:27Z"}