University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 DinI could be a suitable option in drug targeting strategies to reduce SOS mutagenesis DinI could be a suitable option in drug targeting strategies to reduce SOS mutagenesis 1 6 29071 10.22108/bjm.2024.142477.1610 FA Razieh Pourahmad Jaktaji Department of Genetics, Faculty of Science, Shahrekord University, Shahrekord, Iran Sare Mohammadi Department of Genetics, Faculty of Science, Shahrekord University, Shahrekord, Iran Journal Article 2024 08 15 Ciprofloxacin induces the SOS response. Induction of the SOS response confers resistance to ciprofloxacin through activation of DNA polymerase V. However, mutations in lexA, umuDC and especially recA prevent the evolution of resistance to ciprofloxacin. Alternatively, mutations in SOS proteins that regulate RecA activity, such as DinI, can reduce SOS mutagenesis. The aim of this study was to investigate the effect of DinI inactivation on the frequency of mutagenesis and expression of the umuD and rdgC genes after treatment with ciprofloxacin and to examine the promoter region and the 3′ end of the recA gene for possible changes in dinI (SM1 and SM2) mutants. Ciprofloxacin-resistant clones (SM1 and SM2) derived from the JW10481 (dinI- ) strain were used in this study. Mutagenesis analysis and real-time PCR were used to measure the frequency of mutant cells and the expression of umuD and rdgC genes in mutants, respectively. The promoter region and recA gene sequence were examined by PCR amplification and DNA sequencing in dinI- clones. SOS mutagenesis was significantly reduced (P<0.05) in SM1 and SM2 clones. These clones (dinI-) did not show overexpression of the umuD gene. rdgC gene was overexpressed in SM2, but not in the M2 mutant with intact dinI gene. Furthermore, DNA sequencing did not reveal any change in the recA gene sequence. The low frequency of mutagenesis and umuD expression in clones lacking DinI protein activity demonstrated the importance of this protein in SOS mutagenesis. In conclusion, DinI may be a suitable option in drug targeting strategies to enhance the efficacy of ciprofloxacin in combination therapy against a variety of infections caused by Escherichia coli and other Gram-negative bacteria with homologues of this protein. Ciprofloxacin induces the SOS response. Induction of the SOS response confers resistance to ciprofloxacin through activation of DNA polymerase V. However, mutations in lexA, umuDC and especially recA prevent the evolution of resistance to ciprofloxacin. Alternatively, mutations in SOS proteins that regulate RecA activity, such as DinI, can reduce SOS mutagenesis. The aim of this study was to investigate the effect of DinI inactivation on the frequency of mutagenesis and expression of the umuD and rdgC genes after treatment with ciprofloxacin and to examine the promoter region and the 3′ end of the recA gene for possible changes in dinI (SM1 and SM2) mutants. Ciprofloxacin-resistant clones (SM1 and SM2) derived from the JW10481 (dinI- ) strain were used in this study. Mutagenesis analysis and real-time PCR were used to measure the frequency of mutant cells and the expression of umuD and rdgC genes in mutants, respectively. The promoter region and recA gene sequence were examined by PCR amplification and DNA sequencing in dinI- clones. SOS mutagenesis was significantly reduced (P<0.05) in SM1 and SM2 clones. These clones (dinI-) did not show overexpression of the umuD gene. rdgC gene was overexpressed in SM2, but not in the M2 mutant with intact dinI gene. Furthermore, DNA sequencing did not reveal any change in the recA gene sequence. The low frequency of mutagenesis and umuD expression in clones lacking DinI protein activity demonstrated the importance of this protein in SOS mutagenesis. In conclusion, DinI may be a suitable option in drug targeting strategies to enhance the efficacy of ciprofloxacin in combination therapy against a variety of infections caused by Escherichia coli and other Gram-negative bacteria with homologues of this protein.

https://bjm.ui.ac.ir/article_29071_70d812330811b4a612eb9efb5f840430.pdf

University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 The combined effect of light spectra and antagonistic bacteria in inhibiting the growth of Alternaria brassicicola The combined effect of light spectra and antagonistic bacteria in inhibiting the growth of Alternaria brassicicola 7 20 29059 10.22108/bjm.2024.142657.1611 FA Ehsan Rezaei Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran Rohallah Sharifi Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran Saeed Jalali Honarmand Department of Plant Production and Genetic, Razi University, Kermanshah, Iran Journal Article 2024 08 31 Plant growth-promoting rhizobacteria and their metabolites are considered alternatives to chemical pesticides for managing plant diseases. Additionally, light spectra directly affect plant growth and response to stress, as well as the growth and physiology of plant-associated bacteria and fungi. This study aimed to investigate the role of different light spectra on the growth of beneficial bacteria and pathogenic fungi and their antagonistic relationships. This research investigated the effect of full spectrum, red, blue, far-red, UVA, green light and dark conditions on the growth of the antagonistic bacterium Bacillus pumilus INR7 and the plant pathogenic fungus Alternaria brassicicola and the interaction between these two micro organisms under laboratory conditions. The results showed that the light spectra significantly affected the growth of the antagonistic bacterium. Green light had the greatest effect, while UVA had a small effect on the population growth of the bacterium. The light spectra also affected the growth and spore production of A. brassicicola. Blue light increased colony growth, while dark conditions reduced it in the pathogenic fungus. UVA, red, green and blue light showed no significant differences compared to the full spectrum in spore production, dark conditions reduced the spore population. Conversely, UVA increased growth, whereas dark conditions reduced growth of A. brassicicola in the inhibition halo test. Furthermore, green light had the greatest effect and dark conditions the least effect on mycelial growth of A. brassicicola in the presence of volatile compounds from the antagonistic bacterium. The results of these experiments showed that light spectra can influence the physiology of beneficial bacteria and pathogenic fungi, affecting bacterial populations, fungal growth, sporulation rates and their interactions. Plant growth-promoting rhizobacteria and their metabolites are considered alternatives to chemical pesticides for managing plant diseases. Additionally, light spectra directly affect plant growth and response to stress, as well as the growth and physiology of plant-associated bacteria and fungi. This study aimed to investigate the role of different light spectra on the growth of beneficial bacteria and pathogenic fungi and their antagonistic relationships. This research investigated the effect of full spectrum, red, blue, far-red, UVA, green light and dark conditions on the growth of the antagonistic bacterium Bacillus pumilus INR7 and the plant pathogenic fungus Alternaria brassicicola and the interaction between these two micro organisms under laboratory conditions. The results showed that the light spectra significantly affected the growth of the antagonistic bacterium. Green light had the greatest effect, while UVA had a small effect on the population growth of the bacterium. The light spectra also affected the growth and spore production of A. brassicicola. Blue light increased colony growth, while dark conditions reduced it in the pathogenic fungus. UVA, red, green and blue light showed no significant differences compared to the full spectrum in spore production, dark conditions reduced the spore population. Conversely, UVA increased growth, whereas dark conditions reduced growth of A. brassicicola in the inhibition halo test. Furthermore, green light had the greatest effect and dark conditions the least effect on mycelial growth of A. brassicicola in the presence of volatile compounds from the antagonistic bacterium. The results of these experiments showed that light spectra can influence the physiology of beneficial bacteria and pathogenic fungi, affecting bacterial populations, fungal growth, sporulation rates and their interactions.

https://bjm.ui.ac.ir/article_29059_020ed22a9220da9d69c021b8ac582483.pdf

University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 Enhancing the Antimicrobial Efficacy of Acrylic Polymers through in situ Biological Synthesis of Copper Nanocomposites Used in Restoration of Stony Cultural Heritage Enhancing the Antimicrobial Efficacy of Acrylic Polymers through in situ Biological Synthesis of Copper Nanocomposites Used in Restoration of Stony Cultural Heritage 21 33 29053 10.22108/bjm.2024.142295.1605 FA Mandana Lak Department of Microbiology, Faculty of Biological Sciences, Alzahra, Tehran, Iran Parisa Mohammadi Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Research Center for Applied Microbiology and Microbial Biotechnology, Alzahra University, Tehran, Iran Parinaz Ghadam Department of Biotechnology, Faculty of Biological Sciences, Alzahra University Majid Momhad Heravi Department of Chemistry, Faculty of Physics & Chemistry, Alzahra University Shervin Ahmadi Iran Polymer and Petrochemical Institute, Tehran, Iran 0000-0003-1038-5146 Journal Article 2024 07 29 Acrylic polymer is widely used as a protective material for coatings, bridges, ships and locomotives. Additionally, these synthetic polymers are used in the treatment of stone buildings, acting as bonding agents and protective layers. The synthetic polymers can be subjected to various types of degradation, including chemical, physical and biological deterioration. Microorganisms as biological agents can also damage the structure and functionality of synthetic polymers. To enhance the structural integrity and functionality of polymers, nanoparticles can be incorporated into polymers to improve their physical properties and antimicrobial capabilities. Plant extracts can be utilized to synthesize metal nanoparticles. The biological synthesis is a simple, cost-effective and environmentally friendly method. In this study, an in situ method was used to produce the nanocomposite. First, precursors such as aqueous extract of Juglans regia and acrylic polymer were mixed together. This reaction resulted in the formation of nanoparticles within the polymeric structure. The morphological characteristics of the nanocomposite were then studied using Field Emission Scanning Electron Microscopy (FESEM). The presence of copper in this nanocomposite was further analyzed using Energy-Dispersive X-ray Spectroscopy (EDX), where the CuKα and CuKβ peaks confirmed the presence of copper atoms. The antimicrobial activity of the nanocomposite was tested against several strains of bacteria and fungi, including Bacillus subtilis, Pseudomonas aeruginosa, Cladosporium cladosporioides, Aspergillus niger and Alternaria alternata. The antimicrobial activity of the nanocomposite was compared with the acrylic polymer. The nanocomposite synthesized by the in situ method demonstrated higher antimicrobial activity than the acrylic polymer. While the polymer alone could only reduce the number of bacterial and fungal cells by one logarithm, the nanocomposite achieved a reduction of 2-4 logarithms. With these improved antimicrobial properties, it can be concluded that the bioengineered nanocomposite has reasonable potential for use as an antimicrobial coating of stone surfaces. Acrylic polymer is widely used as a protective material for coatings, bridges, ships and locomotives. Additionally, these synthetic polymers are used in the treatment of stone buildings, acting as bonding agents and protective layers. The synthetic polymers can be subjected to various types of degradation, including chemical, physical and biological deterioration. Microorganisms as biological agents can also damage the structure and functionality of synthetic polymers. To enhance the structural integrity and functionality of polymers, nanoparticles can be incorporated into polymers to improve their physical properties and antimicrobial capabilities. Plant extracts can be utilized to synthesize metal nanoparticles. The biological synthesis is a simple, cost-effective and environmentally friendly method. In this study, an in situ method was used to produce the nanocomposite. First, precursors such as aqueous extract of Juglans regia and acrylic polymer were mixed together. This reaction resulted in the formation of nanoparticles within the polymeric structure. The morphological characteristics of the nanocomposite were then studied using Field Emission Scanning Electron Microscopy (FESEM). The presence of copper in this nanocomposite was further analyzed using Energy-Dispersive X-ray Spectroscopy (EDX), where the CuKα and CuKβ peaks confirmed the presence of copper atoms. The antimicrobial activity of the nanocomposite was tested against several strains of bacteria and fungi, including Bacillus subtilis, Pseudomonas aeruginosa, Cladosporium cladosporioides, Aspergillus niger and Alternaria alternata. The antimicrobial activity of the nanocomposite was compared with the acrylic polymer. The nanocomposite synthesized by the in situ method demonstrated higher antimicrobial activity than the acrylic polymer. While the polymer alone could only reduce the number of bacterial and fungal cells by one logarithm, the nanocomposite achieved a reduction of 2-4 logarithms. With these improved antimicrobial properties, it can be concluded that the bioengineered nanocomposite has reasonable potential for use as an antimicrobial coating of stone surfaces.

https://bjm.ui.ac.ir/article_29053_6d735de2eaa7976da9d4ce63826dd320.pdf

University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 Improving antioxidant properties of fermented poultry slaughterhouse byproducts under proteolytic isolated bacteria Improving antioxidant properties of fermented poultry slaughterhouse byproducts under proteolytic isolated bacteria 35 46 29129 10.22108/bjm.2024.142997.1616 FA Reyhaneh Zakeri Department of Biotechnology, Faculty of Biological Sciences, Alzahra University Tayebeh Tayebeh Hadi Toranposhti Department of Biotechnology, Faculty of Biological Sciences, Alzahra University,Tehran, Iran Fakhrisadat Hosseini Department of Biotechnology, Faculty of Biological Sciences, Alzahra University,Tehran, Iran 0000-0002-8368-1133 Journal Article 2024 10 11 The disposal of slaughterhouse waste such as feather meal, blood meal, meat and bone meal and poultry meal poses biological problems. In addition, these wastes contain different amounts of proteins that can be used to improve the nutritional value of these low-value products through microbial processes. In this study, proteolytic isolates, slaughterhouse powder, blood meal, meat meal, and a mixture of meat and blood and bone meal were first isolated from slaughterhouse waste. Then, proteolytic isolates were identified and isolates with better protease properties than other isolates were used for fermentation of the waste. Immersion fermentation was performed at 30 °C and 150 rpm for 5 days by three isolates B4, C3 and A5 with better protease properties than other isolates. The protein content and degree of hydrolysis of the isolates were then measured in 4 sources of slaughterhouse powder, meat powder, blood meal and a mixture of meat and blood and bone meal from slaughterhouse waste. Antioxidant tests were performed based on DPPH radical scavenging and iron chelation methods. Finally, molecular techniques and phylogenetic trees were used to identify the selected strain. The results showed that all hydrolyzed protein wastes removed DPPH and chelated free radicals and had antioxidant properties, and hydrolysis of the wastes could be used for feeding. The disposal of slaughterhouse waste such as feather meal, blood meal, meat and bone meal and poultry meal poses biological problems. In addition, these wastes contain different amounts of proteins that can be used to improve the nutritional value of these low-value products through microbial processes. In this study, proteolytic isolates, slaughterhouse powder, blood meal, meat meal, and a mixture of meat and blood and bone meal were first isolated from slaughterhouse waste. Then, proteolytic isolates were identified and isolates with better protease properties than other isolates were used for fermentation of the waste. Immersion fermentation was performed at 30 °C and 150 rpm for 5 days by three isolates B4, C3 and A5 with better protease properties than other isolates. The protein content and degree of hydrolysis of the isolates were then measured in 4 sources of slaughterhouse powder, meat powder, blood meal and a mixture of meat and blood and bone meal from slaughterhouse waste. Antioxidant tests were performed based on DPPH radical scavenging and iron chelation methods. Finally, molecular techniques and phylogenetic trees were used to identify the selected strain. The results showed that all hydrolyzed protein wastes removed DPPH and chelated free radicals and had antioxidant properties, and hydrolysis of the wastes could be used for feeding.

https://bjm.ui.ac.ir/article_29129_11d75911201b7bc8e2a6a06791dc94ee.pdf

University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 Prevalence of Staphylococcus aureus Nasal Carriage in Athletes Across Varying Body Mass Index Categories Prevalence of Staphylococcus aureus Nasal Carriage in Athletes Across Varying Body Mass Index Categories 47 56 29414 10.22108/bjm.2025.143517.1620 FA Sabriya Abduljabar Department of Biology, College of Science, University of Zakho, Zakho, 42002, Dohuk, Kurdistan Region, Iraq. Ibrahim Abdulqader Naqid Department of Biomedical Sciences, College of Medicine, University of Zakho, Zakho, 42002, Dohuk, Kurdistan Region, Iraq Basim. S. A. Al-Sulaivany Department of Biology, College of Science, University of Zakho, Zakho, 42002, Dohuk, Kurdistan Region, Iraq Journal Article 2024 11 26 Obesity is associated with an increased risk of infection in athletes, and Staphylococcus aureus nasal colonization is a particular concern. This study aimed to investigate whether different BMIs are associated with S. aureus colonization in athletes. S. aureus colonization was assessed using nasal swab cultures from 510 male and female athletes, aged 14–55 years, in a population-based study conducted in Zakho City between 2021 and 2022. Height and weight were measured, and demographic information was analyzed using GraphPad Prism. The nasal carriage rate of S. aureus was 30.8% (157 out of 510 individuals). This rate was higher in obese individuals (46.4%), though this difference was not statistically significant (p<0.113). The highest nasal carriage rate in males was observed in obese individuals (53.85%), while the highest rate in females was observed in the overweight group (46.15%). Our results suggest that an increase in BMI may increase the likelihood of S. aureus nasal colonization in athletes. Future research should focus on the role of obesity in different age groups and genders. Obesity is associated with an increased risk of infection in athletes, and Staphylococcus aureus nasal colonization is a particular concern. This study aimed to investigate whether different BMIs are associated with S. aureus colonization in athletes. S. aureus colonization was assessed using nasal swab cultures from 510 male and female athletes, aged 14–55 years, in a population-based study conducted in Zakho City between 2021 and 2022. Height and weight were measured, and demographic information was analyzed using GraphPad Prism. The nasal carriage rate of S. aureus was 30.8% (157 out of 510 individuals). This rate was higher in obese individuals (46.4%), though this difference was not statistically significant (p<0.113). The highest nasal carriage rate in males was observed in obese individuals (53.85%), while the highest rate in females was observed in the overweight group (46.15%). Our results suggest that an increase in BMI may increase the likelihood of S. aureus nasal colonization in athletes. Future research should focus on the role of obesity in different age groups and genders.

https://bjm.ui.ac.ir/article_29414_c631d67df5a7e69e810ed59618628df1.pdf

University of Isfahan Journal of Microbial Biology 3060-7647 14 55 2025 11 22 Evaluating the impact of Leech Saliva on Streptococcus mutans and Streptococcus sobrinus Evaluating the impact of Leech Saliva on Streptococcus mutans and Streptococcus sobrinus 57 72 29708 10.22108/bjm.2025.144481.1625 FA Zahra Ghafoorzadeh Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Hassan Mohabatkar Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Mandana Behbahani Department of Biotechnology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran. 0000-0003-3240-2672 Zohreh Harsij Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Journal Article 2025 03 02 Leech saliva, containing over 100 biologically active proteins, includes the antimicrobial protein destabilase. Functioning in a manner similar lysozyme, destabilase degrades bacterial cell walls. Tooth decay, caused by Streptococcus mutans and S. sobrinus, necessitates their elimination for prevention and treatment. The effect of leech saliva from different groups on S. mutans and S. sobrinus was investigated. Saliva samples were collected from three leech groups salivated at one, two and three months after feeding. Additionally, the antibacterial properties of destabilase were investigated through bioinformatics and molecular docking. Our study revealed an increase in salivary protein concentration with the duration of starvation, reaching 769 μg/ml after three months. Among the various samples, the saliva concentration of leeches that had undergone three months of starvation exhibited the most potent antibacterial properties. Specifically, it exhibited an antibacterial percentage of 35.3% against S. mutans and 42.6% against S. sobrinus at a concentration of 2 mg/ml. The concentration of 2 mg/ml in the three-month saliva sample also exhibited the highest anti-biofilm percentage against both bacteria, with values of 31.6% for S. mutans and 44.2% for S. sobrinus. Given the global challenge of tooth decay, leech saliva especially destabilase, shows potential for preventing and treating this common dental condition. A significant concentration of destabilase, an antimicrobial protein present in the saliva of leeches, was identified. Also, a novel strategy was proposed to inhibit the formation of biofilms on S. mutans and S. sobrinus, which are commonly associated with tooth decay. Leech saliva, containing over 100 biologically active proteins, includes the antimicrobial protein destabilase. Functioning in a manner similar lysozyme, destabilase degrades bacterial cell walls. Tooth decay, caused by Streptococcus mutans and S. sobrinus, necessitates their elimination for prevention and treatment. The effect of leech saliva from different groups on S. mutans and S. sobrinus was investigated. Saliva samples were collected from three leech groups salivated at one, two and three months after feeding. Additionally, the antibacterial properties of destabilase were investigated through bioinformatics and molecular docking. Our study revealed an increase in salivary protein concentration with the duration of starvation, reaching 769 μg/ml after three months. Among the various samples, the saliva concentration of leeches that had undergone three months of starvation exhibited the most potent antibacterial properties. Specifically, it exhibited an antibacterial percentage of 35.3% against S. mutans and 42.6% against S. sobrinus at a concentration of 2 mg/ml. The concentration of 2 mg/ml in the three-month saliva sample also exhibited the highest anti-biofilm percentage against both bacteria, with values of 31.6% for S. mutans and 44.2% for S. sobrinus. Given the global challenge of tooth decay, leech saliva especially destabilase, shows potential for preventing and treating this common dental condition. A significant concentration of destabilase, an antimicrobial protein present in the saliva of leeches, was identified. Also, a novel strategy was proposed to inhibit the formation of biofilms on S. mutans and S. sobrinus, which are commonly associated with tooth decay.

https://bjm.ui.ac.ir/article_29708_2fccd2e0c92c314e575e9c54ec51b9a1.pdf