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Hao M, Zhao D, Liu W, Yuan N, Tang T, Wang M, Zhai Y, Shi Y, Yang Y, Liu X, Li J, Zhou D, Liu W, Jin Y, Wang A. Deletion of the alr gene in Brucella suis S2 attenuates virulence by enhancing TLR4-NF-κB-NLRP3- mediated host inflammatory responses. Int Immunopharmacol 2024; 137:112443. [PMID: 38897124 DOI: 10.1016/j.intimp.2024.112443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 05/11/2024] [Accepted: 06/05/2024] [Indexed: 06/21/2024]
Abstract
Brucella is an intracellular parasitic bacterium lacking typical virulence factors, and its pathogenicity primarily relies on replication within host cells. In this study, we observed a significant increase in spleen weight in mice immunized with a Brucella strain deleted of the gene for alanine racemase (Alr), the enzyme responsible for alanine racemization (Δalr). However, the bacterial load in the spleen markedly decreased in the mutant strain. Concurrently, the ratio of white pulp to red pulp in the spleen was increased, serum IgG levels were elevated, but no significant damage to other organs was observed. In addition, the inflammatory response was potentiated and the NF-κB-NLRP3 signaling pathway was activated in macrophages (RAW264.7 Cells and Bone Marrow-Derived Cells) infect ed with the Δalr mutant. Further investigation revealed that the Δalr mutant released substantial amounts of protein in a simulated intracellular environment which resulted in heightened inflammation and activation of the TLR4-NF-κB-NLRP3 pathway in macrophages. The consequent cytoplasmic exocytosis reduced intracellular Brucella survival. In summary, cytoplasmic exocytosis products resulting from infection with a Brucella strain deleted of the alr gene effectively activated the TLR4-NFκB-NLRP3 pathway, triggered a robust inflammatory response, and reduced bacterial survival within host cells. Moreover, the Δalr strain exhibits lower toxicity and stronger immunogenicity in mice.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Ningqiu Yuan
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Ting Tang
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yuanhao Yang
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A &F University, Yangling, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China.
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Hao M, Wang M, Tang T, Zhao D, Yin S, Shi Y, Liu X, Wudong G, Yang Y, Zhang M, Qi L, Zhou D, Liu W, Jin Y, Wang A. Regulation of the Gene for Alanine Racemase Modulates Amino Acid Metabolism with Consequent Alterations in Cell Wall Properties and Adhesive Capability in Brucella spp. Int J Mol Sci 2023; 24:16145. [PMID: 38003334 PMCID: PMC10671322 DOI: 10.3390/ijms242216145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/24/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Brucella, a zoonotic facultative intracellular pathogenic bacterium, poses a significant threat both to human health and to the development of the livestock industry. Alanine racemase (Alr), the enzyme responsible for alanine racemization, plays a pivotal role in regulating virulence in this bacterium. Moreover, Brucella mutants with alr gene deletions (Δalr) exhibit potential as vaccine candidates. However, the mechanisms that underlie the detrimental effects of alr knockouts on Brucella pathogenicity remain elusive. Here, initially, we conducted a bioinformatics analysis of Alr, which demonstrated a high degree of conservation of the protein within Brucella spp. Subsequent metabolomics studies unveiled alterations in amino acid pathways following deletion of the alr gene. Furthermore, alr deletion in Brucella suis S2 induced decreased resistance to stress, antibiotics, and other factors. Transmission electron microscopy of simulated macrophage intracellular infection revealed damage to the cell wall in the Δalr strain, whereas propidium iodide staining and alkaline phosphatase and lactate dehydrogenase assays demonstrated alterations in cell membrane permeability. Changes in cell wall properties were revealed by measurements of cell surface hydrophobicity and zeta potential. Finally, the diminished adhesion capacity of the Δalr strain was shown by immunofluorescence and bacterial enumeration assays. In summary, our findings indicate that the alr gene that regulates amino acid metabolism in Brucella influences the properties of the cell wall, which modulates bacterial adherence capability. This study is the first demonstration that Alr impacts virulence by modulating bacterial metabolism, thereby providing novel insights into the pathogenic mechanisms of Brucella spp.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Ting Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Shurong Yin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Gaowa Wudong
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yuanhao Yang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Mengyu Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Lin Qi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China; (M.H.); (M.W.); (T.T.); (D.Z.); (S.Y.); (Y.S.); (X.L.); (G.W.); (Y.Y.); (M.Z.); (L.Q.); (D.Z.); (W.L.); (Y.J.)
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
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Yan XY, Yao JP, Li YQ, Xiao XJ, Yang WQ, Chen SJ, Tang TC, Yang YQ, Qu L, Hou YJ, Chen M, Li Y. Effects of acupuncture on gut microbiota and short-chain fatty acids in patients with functional constipation: a randomized placebo-controlled trial. Front Pharmacol 2023; 14:1223742. [PMID: 37719865 PMCID: PMC10502303 DOI: 10.3389/fphar.2023.1223742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/17/2023] [Indexed: 09/19/2023] Open
Abstract
Objective: To comprehensively evaluate the effect of acupuncture on gut microbiota, identify specific microbes closely related to the clinical efficacy of acupuncture, and explored the role of short-chain fatty acids (SCFAs). Methods: A randomized placebo-controlled trial was conducted with 80 FC patients and 28 healthy controls (HCs). FC patients randomly received 16 acupuncture (n = 40) or sham acupuncture (n = 40) sessions over 4 weeks; HCs received no treatment. The change in the proportion of patients with mean weekly complete spontaneous bowel movements (CSBMs) was considered as the primary outcome measure. Moreover, the composition and the predictive metabolic function of the gut microbiota from feceal samples were analyzed by 16S rRNA gene sequencing, while feceal SCFAs were identified via gas chromatography-mass spectrometry (GC-MS). Results: Compared to sham acupuncture, acupuncture significantly increased the proportion of CSBM responders, and improved spontaneous bowel movements (SBMs), straining, stool consistency, and quality of life. Moreover, Sequencing of 16S rRNA genes revealed that acupuncture improved β-diversity and restored the composition of gut microbiota. Specifically, the abundance of beneficial bacteria such as g_Lactobacillus increased while that of pathogenic bacteria such as g_Pseudomonas decreased after acupuncture, which were significantly correlated with alleviated symptoms. Moreover, ten microbes including g_Coprobacter, g_Lactobacillus, and g_Eubacterium_coprostanoligenes_group might be considered acupuncture-specific microbes, and formed a stable interaction network. Additionally, GC-MS analysis indicated that acupuncture increased the content of butyrate acid in the gut, which was positively correlated with an increase in defecation frequency and a decrease in acupuncture-related pathogens. Finally, acupuncture specific-microbes including g_Coprobacter, g_Lactobacillus, g_Pseudomonas, g_Eubacterium_coprostanoligenes_group, g_Erysipelotrichaceae_UCG.003, g_Prevotellaceae_UCG.001, and g_Rolstonia could accurately predict the clinical efficacy of acupuncture (AUC = 0.918). Conclusion: Acupuncture could effectively improve clinical symptoms in FC patients, and was associated with gut microbiota reshaping and increased butyrate acid levels. Moreover, key microbial genera such as g_Coprobacter and g_Lactobacillus was predictive of acupuncture efficacy in treating FC. Future studies are required to validate the causal relationship between key microbial genera and acupuncture clinical efficacy, and should explore further metabolic pathways for designing personalized treatment strategies. Clinical Trial Registration: http://www.chictr.org.cn, Identifier: ChiCTR2100048831.
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Affiliation(s)
- Xiang-Yun Yan
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jun-Peng Yao
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yan-Qiu Li
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xian-Jun Xiao
- School of Health Preservation and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wan-Qing Yang
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Si-Jue Chen
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Tai-Chun Tang
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yu-Qing Yang
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Liu Qu
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yu-Jun Hou
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Min Chen
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ying Li
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Ibrahim KA, El-Ashrey MK, Kashef MT, Helmy OM. Alanine racemase a promising Helicobacter pylori drug target inhibited by propanoic acid. Microbes Infect 2023; 25:105167. [PMID: 37271368 DOI: 10.1016/j.micinf.2023.105167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 05/23/2023] [Accepted: 05/30/2023] [Indexed: 06/06/2023]
Abstract
Eradication of Helicobacter pylori, the class 1 carcinogen, faces several obstacles, which demand alternative options to conventional drug development methods. Alanine racemase (Alr) was proposed as H. pylori drug target, inhibited by propanoic acid (PA), in a previous in silico study. We investigated the possible treatment of H. pylori infection through Alr inhibition. A new model of H. pylori Alr was built, validated, and the binding of PA to the active site was modelled via molecular docking with a good docking score. PA minimum inhibitory concentration (MIC) against H. pylori ATCC 43504 and six H. pylori clinical isolates ranged from 312.5 to 416.7 ± 180 μg/ml and remained unchanged after 14 serial passages in increasing PA concentrations. The minimum bactericidal concentration of PA was 625 μg/ml. Selective Alr inhibition was confirmed by a significant PA MIC increase with increasing d-alanine concentrations. Similar PA MIC in other tested pathogens was recorded (312.5-625 μg/ml). PA lacked cytotoxicity in tested cell lines and efficiently eradicated H. pylori in a rat infection model. In conclusion, Alr is a promising broad-spectrum drug target, inhibited by PA without resistance development by repeated exposure for 14 serial passages.
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Affiliation(s)
- Kareem A Ibrahim
- Department of Microbiology and Immunology, Faculty of Pharmacy, Egyptian Russian University, Suez Road, Cairo, 11829, Egypt
| | - Mohamed K El-Ashrey
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr Elini St., Cairo, 11562, Egypt; Medicinal Chemistry Department, Faculty of Pharmacy, King Salman International University, Ras-Sedr, South Sinai, Egypt
| | - Mona T Kashef
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
| | - Omneya M Helmy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
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Qiu TA, Lee CJ, Huang C, Lee DK, Rubakhin SS, Romanova EV, Sweedler JV. Biodistribution and racemization of gut-absorbed L/D-alanine in germ-free mice. Commun Biol 2023; 6:851. [PMID: 37587187 PMCID: PMC10432453 DOI: 10.1038/s42003-023-05209-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 08/03/2023] [Indexed: 08/18/2023] Open
Abstract
Microbiome-derived metabolites are important for the microbiome-gut-brain axis and the discovery of new disease treatments. D-Alanine (D-Ala) is found in many animals as a potential co-agonist of the N-methyl-D-aspartate receptors (NMDAR), receptors widely used in the nervous and endocrine systems. The gut microbiome, diet and putative endogenous synthesis are the potential sources of D-Ala in animals, although there is no direct evidence to show the distribution and racemization of gut-absorbed L-/D-Ala with regards to host-microbe interactions in mammals. In this work, we utilized germ-free mice to control the interference from microbiota and isotopically labeled L-/D-Ala to track their biodistribution and racemization in vivo. Results showed time-dependent biodistribution of gut-absorbed D-Ala, particularly accumulation of gut-absorbed D-Ala in pancreatic tissues, brain, and pituitary. No endogenous synthesis of D-Ala via racemization was observed in germ-free mice. The sources of D-Ala in mice were revealed as microbiota and diet, but not endogenous racemization. This work indicates the importance of further investigating the in vivo biological functions of gut-microbiome derived D-Ala, particularly on NMDAR-related activities, for D-Ala as a potential signaling molecules in the microbiome-gut-brain axis.
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Affiliation(s)
- Tian Autumn Qiu
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Cindy J Lee
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Chen Huang
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Dong-Kyu Lee
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
| | - Stanislav S Rubakhin
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Elena V Romanova
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Jonathan V Sweedler
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA.
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Chaiden C, Jaresitthikunchai J, Phaonakrop N, Roytrakul S, Kerdsin A, Nuanualsuwan S. Unlocking the Secrets of Streptococcus suis: A peptidomics comparison of virulent and non-virulent serotypes 2, 14, 18, and 19. PLoS One 2023; 18:e0287639. [PMID: 37384746 PMCID: PMC10310009 DOI: 10.1371/journal.pone.0287639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/09/2023] [Indexed: 07/01/2023] Open
Abstract
Streptococcus suis (S. suis) is an important bacterial pathogen, that causes serious infections in humans and pigs. Although numerous virulence factors have been proposed, their particular role in pathogenesis is still inconclusive. The current study explored putative peptides responsible for the virulence of S. suis serotype 2 (SS2). Thus, the peptidome of highly virulent SS2, less prevalent SS14, and rarely reported serotypes SS18 and SS19 were comparatively analyzed using a high-performance liquid chromatography-mass spectrometry method (LC-MS/MS). Six serotype-specific peptides, 2,3,4,5-tetrahydropyridine-2,6-dicarboxylate N-acetyltransferase (DapH), alanine racemase (Alr), CCA-adding enzyme (CCA), peptide chain release factor 3 (RF3), ATP synthase subunit delta (F0F1-ATPases) and aspartate carbamoyltransferase (ATCase), were expressed moderately to highly only in the SS2 peptidome with p-values of less than 0.05. Some of these proteins are responsible for bacterial cellular stability; especially, Alr was highly expressed in the SS2 peptidome and is associated with peptidoglycan biosynthesis and bacterial cell wall formation. This study indicated that these serotype-specific peptides, which were significantly expressed by virulent SS2, could serve as putative virulence factors to promote its competitiveness with other coexistences in a particular condition. Further in vivo studies of these peptides should be performed to confirm the virulence roles of these identified peptides.
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Affiliation(s)
- Chadaporn Chaiden
- Faculty of Veterinary Sciences, Department of Veterinary Public Health, Chulalongkorn University, Bangkok, Thailand
- Faculty of Veterinary Science, Department of Veterinary Public Health, Center of Excellence for Food and Water Risk Analysis (FAWRA), Chulalongkorn University, Bangkok, Thailand
| | - Janthima Jaresitthikunchai
- Functional Proteomics Technology Laboratory, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology for Development Agency, Pathum Thani, Thailand
| | - Narumon Phaonakrop
- Functional Proteomics Technology Laboratory, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology for Development Agency, Pathum Thani, Thailand
| | - Sittiruk Roytrakul
- Functional Proteomics Technology Laboratory, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology for Development Agency, Pathum Thani, Thailand
| | - Anusak Kerdsin
- Faculty of Public Health, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon, Thailand
| | - Suphachai Nuanualsuwan
- Faculty of Veterinary Sciences, Department of Veterinary Public Health, Chulalongkorn University, Bangkok, Thailand
- Faculty of Veterinary Science, Department of Veterinary Public Health, Center of Excellence for Food and Water Risk Analysis (FAWRA), Chulalongkorn University, Bangkok, Thailand
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Hao M, Wang M, Zhao D, Shi Y, Yuan Y, Li J, Zhai Y, Liu X, Zhou D, Chen H, Lin P, Tang K, Liu W, Jin Y, Wang A. Alr Gene in Brucella suis S2: Its Role in Lipopolysaccharide Biosynthesis and Bacterial Virulence in RAW264.7. Int J Mol Sci 2023; 24:10744. [PMID: 37445922 DOI: 10.3390/ijms241310744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/24/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Brucella suis, the causative agent of brucellosis, poses a significant public health and animal husbandry threat. However, the role of the alanine racemase (alr) gene, which encodes alanine racemase in Brucella, remains unclear. Here, we analyzed an alr deletion mutant and a complemented strain of Brucella suis S2. The knockout strain displayed an unaltered, smooth phenotype in acriflavine agglutination tests but lacked the core polysaccharide portion of lipopolysaccharide (LPS). Genes involved in the LPS synthesis were significantly upregulated in the deletion mutant. The alr deletion strain exhibited reduced intracellular viability in the macrophages, increased macrophage-mediated killing, and upregulation of the apoptosis markers. Bcl2, an anti-apoptotic protein, was downregulated, while the pro-apoptotic proteins, Bax, Caspase-9, and Caspase-3, were upregulated in the macrophages infected with the deletion strain. The infected macrophages showed increased mitochondrial membrane permeability, Cytochrome C release, and reactive oxygen species, activating the mitochondrial apoptosis pathway. These findings revealed that alanine racemase was dispensable in B. suis S2 but influenced the strain's rough features and triggered the mitochondrial apoptosis pathway during macrophage invasion. The deletion of the alr gene reduced the intracellular survival and virulence. This study enhances our understanding of the molecular mechanism underlying Brucella's survival and virulence and, specifically, how alr gene affects host immune evasion by regulating bacterial LPS biosynthesis.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Ye Yuan
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Huatao Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Pengfei Lin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Keqiong Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
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8
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Du J, Huang S, Wu M, Chen S, Zhou W, Zhan L, Huang X. Dlt operon regulates physiological function and cariogenic virulence in Streptococcus mutans. Future Microbiol 2023; 18:225-233. [PMID: 37097048 DOI: 10.2217/fmb-2022-0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Streptococcus mutans is one of the major cariogenic pathogens in the oral cavity. The dlt operon is responsible for the process of D-alanylation of lipoteichoic acid and is related to the virulence of S. mutans. The dlt operon contributes to the adhesion, biofilm formation, stress response, interspecies competitiveness and autolysis of S. mutans. In addition, we have summarized the possible regulatory networks of the dlt operon. This review highlights the significant role of the dlt operon in S. mutans and provides new ideas for ecological caries prevention.
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Affiliation(s)
- Jingyun Du
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Shan Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Minjing Wu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
- Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Shuai Chen
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Wen Zhou
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Ling Zhan
- Division of Pediatric Dentistry, Department of Orofacial Sciences, Department of Preventive & Restorative Dental Sciences, University of California, San Francisco, CA, USA
| | - Xiaojing Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
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9
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Jiang Q, He X, Shui Y, Lyu X, Wang L, Xu L, Chen Z, Zou L, Zhou X, Cheng L, Li M. d-Alanine metabolic pathway, a potential target for antibacterial drug designing in Enterococcus faecalis. Microb Pathog 2021; 158:105078. [PMID: 34245823 DOI: 10.1016/j.micpath.2021.105078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/01/2021] [Indexed: 11/15/2022]
Abstract
Enterococcus faecalis (E. faecalis) is associated with persistent root canal infection because of its biofilm and various virulence factors. However, E. faecalis exhibits extensive drug resistance. d-Alanine (D-Ala) metabolism is essential for bacterial peptidoglycan biosynthesis. d-cycloserine (DCS), a second line drug used in the treatment of Mycobacterium tuberculosis infection, can inhibit two key enzymes in D-Ala metabolism: alanine racemase and d-alanine-d-alanine ligase. The aim of this study was to evaluate the effect of D-Ala metabolism on E. faecalis growth, cell wall integrity, biofilm formation and virulence gene expression by additional DCS with or without D-Ala. The results showed that DCS inhibited the planktonic growth and biofilm formation of E. faecalis in a dose-dependent manner. Both the minimum inhibitory concentration (MIC) and minimum biofilm inhibition concentration (MBIC) of DCS against E. faecalis were 200 μg/ml, whereas 50 μg/ml of DCS could inhibit planktonic growth and biofilm formation effectively. The addition of DCS also resulted in bacterial cell wall damage, biofilm surface roughness increase and biofilm adhesion force reduction. Moreover, the treatment of DCS downregulated the expression of asa1, esp, efaA, gelE, sprE, fsrB and ace genes. However, all of these inhibitory effects of DCS could be rescued by the addition of exogenous D-Ala. Meanwhile, DCS exhibited no toxicity to HGEs and HOKs. Therefore, D-Ala metabolic pathway in E. faecalis is a potential target for drug designing.
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Affiliation(s)
- Qingsong Jiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Xiaoya He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Yusen Shui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Xiaoying Lyu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Liang Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Laijun Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Zhu Chen
- Department of Conservative Dentistry and Endodontics, Guiyang Hospital of Stomatology, Guiyang, China
| | - Ling Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Mingyun Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China.
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10
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Wu M, Huang S, Du J, Jiang S, Cai Z, Zhan L, Huang X. Role of D-alanylation of Streptococcus mutans lipoteichoic acid in interspecies competitiveness. Mol Oral Microbiol 2021; 36:233-242. [PMID: 33977670 DOI: 10.1111/omi.12344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The D-alanylation of lipoteichoic acid (LTA) is essential for the physiological metabolism of Streptococcus mutans (S. mutans). This study was designed to investigate the influence of D-alanylation of LTA on interspecies competitiveness of S. mutans. METHODS The process of D-alanylation was blocked by the inactivation of dltC. Agar competition assays, conditioned medium assays, and qRT-PCR were used to evaluate the production of antimicrobial compounds in S. mutans mutant. Dual-species biofilm was formed to investigate the competitiveness of S. mutans mutant cocultured with S. sanguinis or S. gordonii. RESULTS S. mutans mutant could not produce antimicrobial compounds efficiently when cocultured with commensal bacteria (*p < 0.05). The mutant showed compromised competitiveness in dual-species biofilms. The ratio of the mutant in dual-species biofilms decreased, and the terminal pH of the culture medium in mutant groups (mutant+S. sanguinis/S. gordonii) was higher than that in wild-type groups (*p < 0.05). Scanning electron microscope (SEM) showed weaker demineralization of enamel treated with dual-species biofilms consisting of mutant and commensal bacteria. CONCLUSION D-Alanylation is involved in interspecies competitiveness of S. mutans within oral biofilm by regulating mutacins and lactic acid production, which may modulate the profiles of dental biofilms. Results provide new insights into dental caries prevention and treatment.
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Affiliation(s)
- Minjing Wu
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China.,Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Shan Huang
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Jingyun Du
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Shan Jiang
- School of Stomatology, Shenzhen University Health Science Center, Shenzhen, China
| | - Zhiyu Cai
- Department of Stomatology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Ling Zhan
- Division of Pediatric Dentistry, Department of Orofacial Sciences, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, CA, USA
| | - Xiaojing Huang
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
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11
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Elgamoudi BA, Taha T, Korolik V. Inhibition of Campylobacter jejuni Biofilm Formation by D-Amino Acids. Antibiotics (Basel) 2020; 9:E836. [PMID: 33238583 PMCID: PMC7700173 DOI: 10.3390/antibiotics9110836] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022] Open
Abstract
The ability of bacterial pathogens to form biofilms is an important virulence mechanism in relation to their pathogenesis and transmission. Biofilms play a crucial role in survival in unfavorable environmental conditions, acting as reservoirs of microbial contamination and antibiotic resistance. For intestinal pathogen Campylobacter jejuni, biofilms are considered to be a contributing factor in transmission through the food chain and currently, there are no known methods for intervention. Here, we present an unconventional approach to reducing biofilm formation by C. jejuni by the application of D-amino acids (DAs), and L-amino acids (LAs). We found that DAs and not LAs, except L-alanine, reduced biofilm formation by up to 70%. The treatment of C. jejuni cells with DAs changed the biofilm architecture and reduced the appearance of amyloid-like fibrils. In addition, a mixture of DAs enhanced antimicrobial efficacy of D-Cycloserine (DCS) up to 32% as compared with DCS treatment alone. Unexpectedly, D-alanine was able to reverse the inhibitory effect of other DAs as well as that of DCS. Furthermore, L-alanine and D-tryptophan decreased transcript levels of peptidoglycan biosynthesis enzymes alanine racemase (alr) and D-alanine-D-alanine ligase (ddlA) while D-serine was only able to decrease the transcript levels of alr. Our findings suggest that a combination of DAs could reduce biofilm formation, viability and persistence of C. jejuni through dysregulation of alr and ddlA.
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Affiliation(s)
| | | | - Victoria Korolik
- Institute for Glycomics, Griffith University, Gold Coast QLD 4222, Australia; (B.A.E.); (T.T.)
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12
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Parker MFL, Flavell RR, Luu JM, Rosenberg OS, Ohliger MA, Wilson DM. Small Molecule Sensors Targeting the Bacterial Cell Wall. ACS Infect Dis 2020; 6:1587-1598. [PMID: 32433879 DOI: 10.1021/acsinfecdis.9b00515] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
This review highlights recent efforts to detect bacteria using engineered small molecules that are processed and incorporated similarly to their natural counterparts. There are both scientific and clinical justifications for these endeavors. The use of detectable, cell-wall targeted chemical probes has elucidated microbial behavior, with several fluorescent labeling methods in widespread laboratory use. Furthermore, many existing efforts including ours, focus on developing new imaging tools to study infection in clinical practice. The bacterial cell wall, a remarkably rich and complex structure, is an outstanding target for bacteria-specific detection. Several cell wall components are found in bacteria but not mammals, especially peptidoglycan, lipopolysaccharide, and teichoic acids. As this review highlights, the development of laboratory tools for fluorescence microscopy has vastly outstripped related positron emission tomography (PET) or single photon emission computed tomography (SPECT) radiotracer development. However, there is great synergy between these chemical strategies, which both employ mimicry of endogenous substrates to incorporate detectable structures. As the field of bacteria-specific imaging grows, it will be important to understand the mechanisms involved in microbial incorporation of radionuclides. Additionally, we will highlight the clinical challenges motivating this imaging effort.
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Affiliation(s)
- Matthew F. L. Parker
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States
| | - Robert R. Flavell
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States
| | - Justin M. Luu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States
| | - Oren S. Rosenberg
- Department of Medicine, University of California, San Francisco, San Francisco, California 94158, United States
| | - Michael A. Ohliger
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States
- Department of Radiology, Zuckerberg San Francisco General Hospital, San Francisco, California 94110, United States
| | - David M. Wilson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States
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13
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Muhammad M, Li Y, Gong S, Shi Y, Ju J, Zhao B, Liu D. Purification, Characterization and Inhibition of Alanine Racemase from a Pathogenic Strain of Streptococcus iniae. Pol J Microbiol 2019; 68:331-341. [PMID: 31880879 PMCID: PMC7256847 DOI: 10.33073/pjm-2019-036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 01/25/2023] Open
Abstract
Streptococcus iniae is a pathogenic and zoonotic bacteria that impacted high mortality to many fish species as well as capable of causing serious disease to humans. Alanine racemase (Alr, EC 5.1.1.1) is a pyridoxal-5’-phosphate (PLP)-containing homodimeric enzyme that catalyzes the racemization of L-alanine and D-alanine. In this study, we purified alanine racemase from S. iniae that was isolated from an infected Chinese sturgeon (Acipenser sinensis), as well as determined its biochemical characteristics and inhibitors. The alr gene has an open reading frame (ORF) of 1107 bp, encoding a protein of 369 amino acids, which has a molecular mass of 40 kDa. The enzyme has optimal activity at a temperature of 35°C and a pH of 9.5. It belongs to the PLP-dependent enzymes family and is highly specific to L-alanine. S. iniae Alr (SiAlr) could be inhibited by some metal ions, hydroxylamine and dithiothreitol (DTT). The kinetic parameters Km and Vmax of the enzyme were 33.11 mM, 2426 units/mg for L-alanine, and 14.36 mM, 963.6 units/mg for D-alanine. Finally, the 50% inhibitory concentrations (IC50) values and antibiotic activity of two alanine racemase inhibitors (homogentisic acid and hydroquinone), were determined and found to be effective against both Gram-positive and Gram-negative bacteria employed in this study.
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Affiliation(s)
- Murtala Muhammad
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Yangyang Li
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Siyu Gong
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Yanmin Shi
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Jiansong Ju
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Baohua Zhao
- College of Life Science, Hebei Normal University , Shijiazhuang , China
| | - Dong Liu
- College of Life Science, Hebei Normal University , Shijiazhuang , China
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14
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Nasher F, Aguilar F, Aebi S, Hermans PWM, Heller M, Hathaway LJ. Peptide Ligands of AmiA, AliA, and AliB Proteins Determine Pneumococcal Phenotype. Front Microbiol 2018; 9:3013. [PMID: 30568648 PMCID: PMC6290326 DOI: 10.3389/fmicb.2018.03013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/21/2018] [Indexed: 12/13/2022] Open
Abstract
The Ami-AliA/AliB oligopeptide permease of Streptococcus pneumoniae has been suggested to play a role in environmental sensing and colonisation of the nasopharynx by this human bacterial pathogen by binding peptides derived from bacterial neighbours of other species in the microbiota. Here, we investigated the effects of the peptide ligands of the permease’s substrate binding proteins AmiA, AliA, and AliB on pneumococcal phenotype. AmiA and AliA ligands reduced pneumococcal growth, increased biofilm production and reduced capsule size. In contrast, AliB ligand increased growth and greatly increased bacterial chain length. A decrease in transformation rate was observed in response to all three peptides. Changes in protein expression were also observed, particularly those associated with metabolism and cell wall synthesis. Understanding interspecies bacterial communication and its effect on development of colonising versus invasive phenotypes has the potential to reveal new targets to tackle and prevent pneumococcal infections.
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Affiliation(s)
- Fauzy Nasher
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Fernando Aguilar
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Suzanne Aebi
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Peter W M Hermans
- Janssen Vaccines and Prevention, Leiden, Netherlands.,Julius Center, UMC Utrecht, Utrecht, Netherlands
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
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15
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Liu S, Wei Y, Zhou X, Zhang K, Peng X, Ren B, Chen V, Cheng L, Li M. Function of alanine racemase in the physiological activity and cariogenicity of Streptococcus mutans. Sci Rep 2018; 8:5984. [PMID: 29654290 PMCID: PMC5899142 DOI: 10.1038/s41598-018-24295-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/29/2018] [Indexed: 02/05/2023] Open
Abstract
The enzyme alanine racemase (Alr) has been a new target for the development of antibacterial drugs based on the involvement of D-Ala in bacterial cell wall biosynthesis. Our previous study noted that Alr is essential for the growth and interspecies competitiveness of S. mutans, the major causative organism of dental caries. However, physiological activity and cariogenicity of S. mutans affected by Alr remains unknown. The current study examined the biofilm biomass, biofilm structure, extracellular polysaccharide (EPS) synthesis, glucosyltransferase (gtf) gene expression, acid production and acid tolerance in the alr-mutant strain. We found that biofilm formation, biofilm structure, and EPS synthesis was in a D-Ala dose-dependent manner. Biofilm structure was loose in alr-mutant group and the ratio of EPS/bacteria was also elevated. Additionally, the expression levels of multiple gtfs were up-regulated, and acid tolerance was decreased. We also established in vivo models of dental caries and found that the incidence and severity of the caries were decreased in the alr-mutant group in comparison to the parental S. mutans group. Our in vivo and in vitro experiments demonstrate that Alr is essential for the cariogenicity of S. mutans and that Alr might be a potential target for the prevention and treatment of caries.
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Affiliation(s)
- Shiyu Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yuan Wei
- Department of Endodontology, Nanjing Stomatological Hospital, Medical School of Nanjing University, NO. 30 Zhongyang Road, Nanjing, 210008, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Keke Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China
| | - Xian Peng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China
| | - Biao Ren
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China
| | | | - Lei Cheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China. .,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
| | - Mingyun Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, NO. 14, 3rd Section of South RenMin Rd, Chengdu, Sichuan, 610041, China.
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16
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Wang S, Wang H, Ren B, Li H, Weir MD, Zhou X, Oates TW, Cheng L, Xu HHK. Do quaternary ammonium monomers induce drug resistance in cariogenic, endodontic and periodontal bacterial species? Dent Mater 2017; 33:1127-1138. [PMID: 28755761 DOI: 10.1016/j.dental.2017.07.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/18/2017] [Accepted: 07/08/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Antibacterial monomers were developed to combat oral biofilm acids and caries; however, little is known on whether quaternary ammonium monomers (QAMs) would induce drug resistance in oral bacteria. The objective of this study was to investigate the effects of new antimicrobial monomers dimethylaminohexadecyl methacrylate (DMAHDM) and dimethylaminododecyl methacrylate (DMADDM) on the induction of drug resistance in eight species of cariogenic, endodontic and periodontal bacteria for the first time. METHODS Streptococcus mutans (S. mutans), Streptococcus sanguis, Streptococcus gordonii, Enterococcus faecalis (E. faecalis), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Fusobacterium nucleatum (F. nucleatum), Porphyromonas gingivalis (P. gingivalis), and Prevotella intermedia (P. intermedia) were tested. Minimum inhibitory concentration (MIC) was assessed using chlorhexidine (CHX) as control. Minimal bactericidal concentration (MBC), bacterial growth and membrane permeability properties were also investigated. RESULTS CHX induced drug resistance in four species. DMAHDM did not induce any resistance. DMADDM induced drug resistance in only one benign species S. gordonii. The DMADDM-resistant and CHX-resistant S. gordonii had the same MIC and MBC values as S. gordonii parental strain against DMAHDM (p>0.1), hence DMAHDM effectively inhibited the resistant strains. The resistant strains had slower growth metabolism than parental strain. SIGNIFICANCE DMAHDM induced no drug resistance, and DMADDM had much less drug resistance than the commonly-used CHX in the eight common oral species. With its potent antimicrobial functions shown previously, the new DMAHDM is promising for applications in restorative, preventive, periodontal and endodontic treatments to combat cariogenic and pathological bacteria with no drug resistance in all tested species.
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Affiliation(s)
- Suping Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Haohao Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Biao Ren
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Hao Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Michael D Weir
- Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Thomas W Oates
- Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA.
| | - Hockin H K Xu
- Department of Endodontics, Periodontics and Prosthodontics, University of Maryland Dental School, Baltimore, MD 21201, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore County, MD 21250, USA.
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