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Wen Sheng Xiang - One of the best experts on this subject based on the ideXlab platform.
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Two novel Milbemycin derivatives from the genetically engineered strain Streptomyces avermitilis AVE-H39.
The Journal of antibiotics, 2020Co-Authors: Ji Zhang, Jidong Wang, Shao-yong Zhang, Hao Zhikui, Li-qin Zhang, Wen Sheng XiangAbstract:Two novel Milbemycin derivatives, 5,27-epoxy-13α-hydroxy Milbemycin β11 (1) and 5,27-epoxy-13α-hydroxy-25-ethyl Milbemycin β11 (2), were isolated from the genetically engineered strain Streptomyces avermitilis AVE-H39. Their structures were elucidated through the interpretation of HR-ESIMS and extensive NMR spectroscopic data. Compounds 1 and 2 exhibited moderate acaricidal and nematicidal activities.
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sbbr sbba an important arpa afsa like system regulates Milbemycin production in streptomyces bingchenggensis
Frontiers in Microbiology, 2018Co-Authors: Haiyan Wang, Xiang Jing Wang, Yanyan Zhang, Xiaowei Guo, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of Milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating Milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of Milbemycin, while deletion of sbbA enhanced Milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for Milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24sbh ) and four well-known global regulatory genes (e.g., glnRsbh , wblAsbh , atrAsbh , and mtrA/Bsbh ). These data suggest that SbbR is not only a direct activator of Milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls Milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in Milbemycin biosynthesis, but also provide a basis for an approach to improve Milbemycin production via genetic manipulation of SbbR/SbbA system.
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Data_Sheet_1_SbbR/SbbA, an Important ArpA/AfsA-Like System, Regulates Milbemycin Production in Streptomyces bingchenggensis.docx
2018Co-Authors: Haiyan Wang, Xiang Jing Wang, Yanyan Zhang, Xiaowei Guo, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of Milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating Milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of Milbemycin, while deletion of sbbA enhanced Milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for Milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24sbh) and four well-known global regulatory genes (e.g., glnRsbh, wblAsbh, atrAsbh, and mtrA/Bsbh). These data suggest that SbbR is not only a direct activator of Milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls Milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in Milbemycin biosynthesis, but also provide a basis for an approach to improve Milbemycin production via genetic manipulation of SbbR/SbbA system.
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New 5-oxoMilbemycins from a Genetically Engineered Strain Streptomyces bingchenggensis BCJ60
ACG Publications, 2017Co-Authors: Hui Zhang, Jidong Wang, Ji Zhang, Shao-yong Zhang, Haiyan Wang, Anliang Chen, Wen Sheng XiangAbstract:Two new 5-oxoMilbemycins, 27-aldehyde -5-oxo Milbemycin β 12 (1) and 2-hydroxyMilbemycin K (2) , were isolated from a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined by comprehensive analyses of its 1H and 13C NMR, COSY, HMQC, and HMBC spectroscopic, HR - E S I - MS mass spectrometric and comparison with data from the literature . Preliminary studies showed that 27-aldehyde -5-oxo Milbemycin β 12 (1) and 2-hydroxyMilbemycin K (2) possessed strong acaricidal and nematocidal activities
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characterization of a pathway specific activator of Milbemycin biosynthesis and improved Milbemycin production by its overexpression in streptomyces bingchenggensis
Microbial Cell Factories, 2016Co-Authors: Yanyan Zhang, Xiang Jing Wang, Haiyan Wang, Hui Liu, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolides with potent anthelminthic and insecticidal activity, are produced by several Streptomyces and used widely in agricultural, medical and veterinary fields. Milbemycin A3 and A4, the main components produced by Streptomyces bingchenggensis, have been developed as an acaricide to control mites. The subsequent structural modification of Milbemycin A3/A4 led to other commercial products, such as Milbemycin oxime, lepimectin and latidectin. Despite its importance, little is known about the regulation of Milbemycin biosynthesis, which has hampered efforts to enhance Milbemycin production via engineering regulatory genes. milR, a regulatory gene in the Milbemycin (mil) biosynthetic gene cluster of S. bingchenggensis, encodes a large ATP-binding regulator of the LuxR family (LAL family), which contains an ATPase domain at its N-terminus and a LuxR-like DNA-binding domain at the C-terminus. Gene disruption and genetic complementation revealed that milR plays an important role in the biosynthesis of Milbemycin. β-glucuronidase assays and transcriptional analysis showed that MilR activates the expression of the milA4-E operon and milF directly, and activates the other mil genes indirectly. Site-directed mutagenesis confirmed that the ATPase domain is indispensable for MilR’s function, and particularly mutation of the conserved amino acids K37A, D122A and D123A, led to the loss of MilR function for Milbemycin biosynthesis. Overexpression of an extra copy of milR under the control of its native promoter significantly increased production of Milbemycin A3/A4 in a high-producing industrial strain S. bingchenggensis BC04. A LAL regulator, MilR, was characterized in the mil gene cluster of S. bingchenggensis BC04. MilR could activate Milbemycin biosynthesis through direct interaction with the promoter of the milA4-E operon and that of milF. Overexpression of milR increased Milbemycin A3/A4 production by 38 % compared with the parental strain BC04, suggesting that genetic manipulation of this activator gene could enhance the yield of antibiotics.
Rudolf Schenker - One of the best experts on this subject based on the ideXlab platform.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: Rudolf Schenker, N J Archer, Ivan Gerard Horak, P SwartAbstract:Abstract The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi , following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5 mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5 mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly ( p S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: Rudolf Schenker, N J Archer, Ivan Gerard Horak, P SwartAbstract:Abstract The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi , following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5 mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5 mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly ( p S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: D J Kok, N J Archer, Ivan Gerard Horak, Rudolf Schenker, P SwartAbstract:The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi, following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly (p<0.05) reduced both the number of S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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the use of Milbemycin oxime in a prophylactic anthelmintic programme to protect puppies raised in an endemic area against infection with spirocerca lupi
Veterinary Parasitology, 2010Co-Authors: E.j. Williams, N J Archer, Rudolf Schenker, Ivan Gerard HorakAbstract:Abstract Spirocerca lupi is primarily a parasite of dogs and other carnivores. Clinical signs of infection are regurgitation, vomiting, weight loss, coughing and dyspnoea. Sudden death can also occur due to a ruptured aortic aneurysm. In this study, the Eastern Cape Province of South Africa was identified as an area with a high prevalence of S. lupi. A subsequent investigation, to evaluate the efficacy of Milbemycin oxime as a prophylactic agent for canine spirocercosis, involved 58 puppies that were raised in this area in accordance with local husbandry procedures. Approximately half of the puppies served as untreated controls. Puppies in the treatment group received Milbemycin oxime (minimum dose of 0.5 mg/kg body weight) when they were between 2 and 6 weeks old. They then received five further treatments at approximately 28-day intervals. The treatment was orally administered in tablet form. After the sixth treatment, puppies from both the treated and control groups were euthanized and post-mortem examinations were performed. Twenty-four out of 27 dogs in the untreated control group had become infected by S. lupi. In comparison, only 19 out of 31 dogs in the treatment group had evidence of spirocercosis as demonstrated by aortic nodules. The prophylactic regimen reduced the severity of aortic lesions and prevented 86.5% of S. lupi from becoming established in the thoracic aorta. It also prevented 89.4% of S. lupi from becoming established in the oesophagus and significantly reduced the number of oesophageal nodules. Milbemycin oxime markedly reduced the level and severity of S. lupi infection in treated puppies raised in an endemic area of South Africa. It deserves further evaluation as a potential prophylactic treatment for spirocercosis.
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therapeutic and prophylactic efficacy of Milbemycin oxime interceptor against thelazia callipaeda in naturally exposed dogs
Veterinary Parasitology, 2008Co-Authors: Ezio Ferroglio, Rudolf Schenker, Luca Rossi, E Tomio, P BianciardiAbstract:Two trials were conducted to evaluate the therapeutic and prophylactic activity of Milbemycin oxime (Interceptor, Novartis Animal Health) against the eye-worm Thelazia callipaeda (Spirurida, Thelaziidae) infection. In Trial 1, the therapeutic efficacy of Milbemycin oxime was evaluated in 55 naturally infected dogs treated with min. 0.5mg/kg Milbemycin oxime. The dogs were clinically examined for the presence of eyeworms before and again 7 days after treatment. Dogs still positive were given a second treatment and re-checked again a week later. Forty-eight of the 55 dogs tested negative 1 week after treatment (87.3% reduction of infection rate). Following the second treatment 6 of these 7 dogs tested negative 1 week later resulting, after two treatments, in a reduction of infection rate of 98.2%. In Trial 2, the prophylactic efficacy of Milbemycin oxime was evaluated in 60 uninfected dogs. Thirty dogs were treated with Milbemycin oxime monthly from June to November with the recommended dose rate for the prevention of heartworm disease (> or =0.5mg/kg), 30 dogs served as untreated controls. At the end of the trail 1 dog in the treated group and 10 dogs in the control group became infected during the trial. The incidence of infection differed significantly between treated and control dogs (p=0.0056). The efficacy of the prophylactic use of a monthly treatment with Milbemycin oxime showed 90% efficacy in reducing T. callipaeda infection rate.
Xiang Jing Wang - One of the best experts on this subject based on the ideXlab platform.
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sbbr sbba an important arpa afsa like system regulates Milbemycin production in streptomyces bingchenggensis
Frontiers in Microbiology, 2018Co-Authors: Haiyan Wang, Xiang Jing Wang, Yanyan Zhang, Xiaowei Guo, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of Milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating Milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of Milbemycin, while deletion of sbbA enhanced Milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for Milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24sbh ) and four well-known global regulatory genes (e.g., glnRsbh , wblAsbh , atrAsbh , and mtrA/Bsbh ). These data suggest that SbbR is not only a direct activator of Milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls Milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in Milbemycin biosynthesis, but also provide a basis for an approach to improve Milbemycin production via genetic manipulation of SbbR/SbbA system.
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SbbR/SbbA, an Important ArpA/AfsA-Like System, Regulates Milbemycin Production in Streptomyces bingchenggensis
Frontiers Media S.A., 2018Co-Authors: Haiyan Wang, Xiang Jing Wang, Xiaowei Guo, Yanyan ZhangAbstract:Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of Milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating Milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of Milbemycin, while deletion of sbbA enhanced Milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for Milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24sbh) and four well-known global regulatory genes (e.g., glnRsbh, wblAsbh, atrAsbh, and mtrA/Bsbh). These data suggest that SbbR is not only a direct activator of Milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls Milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in Milbemycin biosynthesis, but also provide a basis for an approach to improve Milbemycin production via genetic manipulation of SbbR/SbbA system
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Data_Sheet_1_SbbR/SbbA, an Important ArpA/AfsA-Like System, Regulates Milbemycin Production in Streptomyces bingchenggensis.docx
2018Co-Authors: Haiyan Wang, Xiang Jing Wang, Yanyan Zhang, Xiaowei Guo, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolide antibiotics, are used widely as insecticides and anthelmintics. Previously, a limited understanding of the transcriptional regulation of Milbemycin biosynthesis has hampered efforts to enhance antibiotic production by engineering of regulatory genes. Here, a novel ArpA/AfsA-type system, SbbR/SbbA (SBI_08928/SBI_08929), has been identified to be involved in regulating Milbemycin biosynthesis in the industrial strain S. bingchenggensis BC04. Inactivation of sbbR in BC04 resulted in markedly decreased production of Milbemycin, while deletion of sbbA enhanced Milbemycin production. Electrophoresis mobility shift assays (EMSAs) and DNase I footprinting studies showed that SbbR has a specific DNA-binding activity for the promoters of milR (the cluster-situated activator gene for Milbemycin production) and the bidirectionally organized genes sbbR and sbbA. Transcriptional analysis suggested that SbbR directly activates the transcription of milR, while represses its own transcription and that of sbbA. Moreover, 11 novel targets of SbbR were additionally found, including seven regulatory genes located in secondary metabolite biosynthetic gene clusters (e.g., sbi_08420, sbi_08432, sbi_09158, sbi_00827, sbi_01376, sbi_09325, and sig24sbh) and four well-known global regulatory genes (e.g., glnRsbh, wblAsbh, atrAsbh, and mtrA/Bsbh). These data suggest that SbbR is not only a direct activator of Milbemycin production, but also a pleiotropic regulator that controls the expression of other cluster-situated regulatory genes and global regulatory genes. Overall, this study reveals the upper-layer regulatory system that controls Milbemycin biosynthesis, which will not only expand our understanding of the complex regulation in Milbemycin biosynthesis, but also provide a basis for an approach to improve Milbemycin production via genetic manipulation of SbbR/SbbA system.
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characterization of a pathway specific activator of Milbemycin biosynthesis and improved Milbemycin production by its overexpression in streptomyces bingchenggensis
Microbial Cell Factories, 2016Co-Authors: Yanyan Zhang, Xiang Jing Wang, Haiyan Wang, Hui Liu, Wen Sheng XiangAbstract:Milbemycins, a group of 16-membered macrolides with potent anthelminthic and insecticidal activity, are produced by several Streptomyces and used widely in agricultural, medical and veterinary fields. Milbemycin A3 and A4, the main components produced by Streptomyces bingchenggensis, have been developed as an acaricide to control mites. The subsequent structural modification of Milbemycin A3/A4 led to other commercial products, such as Milbemycin oxime, lepimectin and latidectin. Despite its importance, little is known about the regulation of Milbemycin biosynthesis, which has hampered efforts to enhance Milbemycin production via engineering regulatory genes. milR, a regulatory gene in the Milbemycin (mil) biosynthetic gene cluster of S. bingchenggensis, encodes a large ATP-binding regulator of the LuxR family (LAL family), which contains an ATPase domain at its N-terminus and a LuxR-like DNA-binding domain at the C-terminus. Gene disruption and genetic complementation revealed that milR plays an important role in the biosynthesis of Milbemycin. β-glucuronidase assays and transcriptional analysis showed that MilR activates the expression of the milA4-E operon and milF directly, and activates the other mil genes indirectly. Site-directed mutagenesis confirmed that the ATPase domain is indispensable for MilR’s function, and particularly mutation of the conserved amino acids K37A, D122A and D123A, led to the loss of MilR function for Milbemycin biosynthesis. Overexpression of an extra copy of milR under the control of its native promoter significantly increased production of Milbemycin A3/A4 in a high-producing industrial strain S. bingchenggensis BC04. A LAL regulator, MilR, was characterized in the mil gene cluster of S. bingchenggensis BC04. MilR could activate Milbemycin biosynthesis through direct interaction with the promoter of the milA4-E operon and that of milF. Overexpression of milR increased Milbemycin A3/A4 production by 38 % compared with the parental strain BC04, suggesting that genetic manipulation of this activator gene could enhance the yield of antibiotics.
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designed biosynthesis of 25 methyl and 25 ethyl ivermectin with enhanced insecticidal activity by domain swap of avermectin polyketide synthase
Microbial Cell Factories, 2015Co-Authors: Ji Zhang, Yi Jun Yan, Shengxiong Huang, Xiang Jing Wang, Wen Sheng XiangAbstract:Avermectin and Milbemycin are important 16-membered macrolides that have been widely used as pesticides in agriculture. However, the wide use of these pesticides inevitably causes serious drug resistance, it is therefore imperative to develop new avermectin and Milbemycin analogs. The biosynthetic gene clusters of avermectin and Milbemycin have been identified and the biosynthetic pathways have been elucidated. Combinatorial biosynthesis by domain swap provides an efficient strategy to generate chemical diversity according to the module polyketide synthase (PKS) assembly line. The substitution of aveDH2-KR2 located in avermectin biosynthetic gene cluster in the industrial avermectin-producing strain Streptomyces avermitilis NA-108 with the DNA regions milDH2-ER2-KR2 located in Milbemycin biosynthetic gene cluster in Streptomyces bingchenggensis led to S. avermitilis AVE-T27, which produced ivermectin B1a with high yield of 3450 ± 65 μg/ml. The subsequent replacement of aveLAT-ACP encoding the loading module of avermectin PKS with milLAT-ACP encoding the loading module of Milbemycin PKS led to strain S. avermitilis AVE-H39, which produced two new avermectin derivatives 25-ethyl and 25-methyl ivermectin (1 and 2) with yields of 951 ± 46 and 2093 ± 61 μg/ml, respectively. Compared to commercial insecticide ivermectin, the mixture of 25-methyl and 25-ethyl ivermectin (2:1 = 3:7) exhibited 4.6-fold increase in insecticidal activity against Caenorhabditis elegans. Moreover, the insecticidal activity of the mixture of 25-methyl and 25-ethyl ivermectin was 2.5-fold and 5.7-fold higher than that of Milbemycin A3/A4 against C. elegans and the second-instar larva of Mythimna separate, respectively. Two new avermectin derivatives 25-methyl and 25-ethyl ivermectin were generated by the domain swap of avermectin PKS. The enhanced insecticidal activity of 25-methyl and 25-ethyl ivermectin implied the potential use as insecticide in agriculture. Furthermore, the high yield and genetic stability of the engineered strains S. avermitilis AVE-T27 and AVE-H39 suggested the enormous potential in industrial production of the commercial insecticide ivermectin and 25-methyl/25-ethyl ivermectins, respectively.
P Swart - One of the best experts on this subject based on the ideXlab platform.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: Rudolf Schenker, N J Archer, Ivan Gerard Horak, P SwartAbstract:Abstract The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi , following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5 mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5 mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly ( p S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: Rudolf Schenker, N J Archer, Ivan Gerard Horak, P SwartAbstract:Abstract The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi , following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5 mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5 mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly ( p S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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the efficacy of Milbemycin oxime against pre adult spirocerca lupi in experimentally infected dogs
Veterinary Parasitology, 2011Co-Authors: D J Kok, N J Archer, Ivan Gerard Horak, Rudolf Schenker, P SwartAbstract:The aim of this investigation was to determine the efficacy of Milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi, following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, Milbemycin oxime (minimum dose 0.5mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, Milbemycin oxime (also at a minimum dose of 0.5mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with Milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly (p<0.05) reduced both the number of S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of Milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of Milbemycin oxime only began after the larvae had completed their first stage of migration.
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Two novel Milbemycin derivatives from the genetically engineered strain Streptomyces avermitilis AVE-H39.
The Journal of antibiotics, 2020Co-Authors: Ji Zhang, Jidong Wang, Shao-yong Zhang, Hao Zhikui, Li-qin Zhang, Wen Sheng XiangAbstract:Two novel Milbemycin derivatives, 5,27-epoxy-13α-hydroxy Milbemycin β11 (1) and 5,27-epoxy-13α-hydroxy-25-ethyl Milbemycin β11 (2), were isolated from the genetically engineered strain Streptomyces avermitilis AVE-H39. Their structures were elucidated through the interpretation of HR-ESIMS and extensive NMR spectroscopic data. Compounds 1 and 2 exhibited moderate acaricidal and nematicidal activities.
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New 5-oxoMilbemycins from a Genetically Engineered Strain Streptomyces bingchenggensis BCJ60
ACG Publications, 2017Co-Authors: Hui Zhang, Jidong Wang, Ji Zhang, Shao-yong Zhang, Haiyan Wang, Anliang Chen, Wen Sheng XiangAbstract:Two new 5-oxoMilbemycins, 27-aldehyde -5-oxo Milbemycin β 12 (1) and 2-hydroxyMilbemycin K (2) , were isolated from a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined by comprehensive analyses of its 1H and 13C NMR, COSY, HMQC, and HMBC spectroscopic, HR - E S I - MS mass spectrometric and comparison with data from the literature . Preliminary studies showed that 27-aldehyde -5-oxo Milbemycin β 12 (1) and 2-hydroxyMilbemycin K (2) possessed strong acaricidal and nematocidal activities
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designed biosynthesis of 25 methyl and 25 ethyl ivermectin with enhanced insecticidal activity by domain swap of avermectin polyketide synthase
Microbial Cell Factories, 2015Co-Authors: Ji Zhang, Yi Jun Yan, Shengxiong Huang, Xiang Jing Wang, Wen Sheng XiangAbstract:Avermectin and Milbemycin are important 16-membered macrolides that have been widely used as pesticides in agriculture. However, the wide use of these pesticides inevitably causes serious drug resistance, it is therefore imperative to develop new avermectin and Milbemycin analogs. The biosynthetic gene clusters of avermectin and Milbemycin have been identified and the biosynthetic pathways have been elucidated. Combinatorial biosynthesis by domain swap provides an efficient strategy to generate chemical diversity according to the module polyketide synthase (PKS) assembly line. The substitution of aveDH2-KR2 located in avermectin biosynthetic gene cluster in the industrial avermectin-producing strain Streptomyces avermitilis NA-108 with the DNA regions milDH2-ER2-KR2 located in Milbemycin biosynthetic gene cluster in Streptomyces bingchenggensis led to S. avermitilis AVE-T27, which produced ivermectin B1a with high yield of 3450 ± 65 μg/ml. The subsequent replacement of aveLAT-ACP encoding the loading module of avermectin PKS with milLAT-ACP encoding the loading module of Milbemycin PKS led to strain S. avermitilis AVE-H39, which produced two new avermectin derivatives 25-ethyl and 25-methyl ivermectin (1 and 2) with yields of 951 ± 46 and 2093 ± 61 μg/ml, respectively. Compared to commercial insecticide ivermectin, the mixture of 25-methyl and 25-ethyl ivermectin (2:1 = 3:7) exhibited 4.6-fold increase in insecticidal activity against Caenorhabditis elegans. Moreover, the insecticidal activity of the mixture of 25-methyl and 25-ethyl ivermectin was 2.5-fold and 5.7-fold higher than that of Milbemycin A3/A4 against C. elegans and the second-instar larva of Mythimna separate, respectively. Two new avermectin derivatives 25-methyl and 25-ethyl ivermectin were generated by the domain swap of avermectin PKS. The enhanced insecticidal activity of 25-methyl and 25-ethyl ivermectin implied the potential use as insecticide in agriculture. Furthermore, the high yield and genetic stability of the engineered strains S. avermitilis AVE-T27 and AVE-H39 suggested the enormous potential in industrial production of the commercial insecticide ivermectin and 25-methyl/25-ethyl ivermectins, respectively.
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MOESM1 of Designed biosynthesis of 25-methyl and 25-ethyl ivermectin with enhanced insecticidal activity by domain swap of avermectin polyketide synthase
2015Co-Authors: Ji Zhang, Yi Jun Yan, Shengxiong Huang, Xiang Jing Wang, Wen Sheng XiangAbstract:Additional file 1: Figure S1. Organizations of avermectin and Milbemycin biosynthetic gene clusters
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combined application of plasma mutagenesis and gene engineering leads to 5 oxoMilbemycins a3 a4 as main components from streptomyces bingchenggensis
Applied Microbiology and Biotechnology, 2014Co-Authors: Haiyan Wang, Ji Zhang, Xiang Jing Wang, Yuejing Zhang, Bo Zhang, Chongxi Liu, Wen Sheng XiangAbstract:Milbemycin oxime has been commercialized as effective anthelmintics in the fields of animal health, agriculture, and human infections. Currently, Milbemycin oxime is synthesized by a two-step chemical reaction, which involves the ketonization of Milbemycins A3/A4 to yield the intermediates 5-oxoMilbemycins A3/A4 using CrO3 as catalyst. Due to the low efficiency and environmental unfriendliness of the ketonization of Milbemycins A3/A4, it is imperative to develop alternative strategies to produce 5-oxoMilbemycins A3/A4. In this study, the atmospheric and room temperature plasma (ARTP) mutation system was first employed to treat Milbemycin-producing strain Streptomyces bingchenggensis, and a mutant strain BC-120-4 producing Milbemycins A3, A4, B2, and B3 as main components was obtained, which favors the construction of genetically engineered strains producing 5-oxoMilbemycins. Importantly, the Milbemycins A3/A4 yield of BC-120-4 reached 3,890 ± 52 g/l, which was approximately two times higher than that of the initial strain BC-109-6 (1,326 ± 37 g/l). The subsequent interruption of the gene milF encoding a C5-ketoreductase responsible for the ketonization of Milbemycins led to strain BCJ60 (∆milF) with the production of 5-oxoMilbemycins A3/A4 and the elimination of Milbemycins A3, A4, B2, and B3. The high 5-oxoMilbemycins A3/A4 yield (3,470 ± 147 g/l) and genetic stability of BCJ60 implied the potential use in industry to prepare 5-oxoMilbemycins A3/A4 for the semisynthesis of Milbemycins oxime.