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Saxena VK, Vedamurthy GV, Swarnkar CP, Kadam V, Onteru SK, Ahmad H, Singh R. De novo pathway is an active metabolic pathway of cysteine synthesis in Haemonchus contortus. Biochimie 2021; 187:110-120. [PMID: 34082042 DOI: 10.1016/j.biochi.2021.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/19/2021] [Accepted: 05/25/2021] [Indexed: 01/25/2023]
Abstract
Haemonchus contortus, commonly known as Barber's pole worm, is an economically important gastrointestinal nematode of sheep and goats especially in tropical and sub-tropical regions of the world. Cysteine synthesis is a very important metabolic pathway for the parasite, however the functional aspects of cysteine synthesis in parasite are largely unknown. The key question which we have investigated in the study is; whether the parasite uses a de novo pathway of cysteine synthesis, which is unknown in multicellular organisms of the animal kingdom and known to be absent in mammals. Directional cloning of the cysteine synthase (CS) gene was done in pET303 champion vector using restriction sites XbaI and XhoI. The CS gene of the H.contortus was closely related to CS-A protein of Oesophagostomum dentatum and a hypothetical protein of Ancylostoma ceylanicum. Recombinant protein of the H contortus CS (rHC-CS) gene was expressed using pET303 vector in pLysS BL21 strain of E.coli and subsequently purified by Ni-NTA affinity chromatography. Western blot using anti-His tag antibody confirmed the presence of rHC-CS. Biochemical assay, FTIR and enzyme kinetics studies revealed that rHC-CS used O-acetyl serine as substrate to produce cysteine using de novo pathway and CS activity was also confirmed with the homogenate of H.contortus. Upregulation of CS transcripts in the adult and its downregulation in the L3 larval stage suggests that de novo pathway contributes to the cysteine requirement of mature H.contortus. It is concluded that de novo pathway is an active metabolic pathway in H.contortus.
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Affiliation(s)
- Vijay Kumar Saxena
- Molecular Physiology Laboratory, Division of Physiology and Biochemistry, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India.
| | - G V Vedamurthy
- Livestock Research Centre, Southren Regional Station, National Dairy Research Institute, ICAR-NDRI (SRS), Bengaluru, Karnataka, 560030, India
| | - C P Swarnkar
- Animal Health Division, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India
| | - Vinod Kadam
- Textile Manufacturing and Textile Chemistry Division, ICAR- Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, 304501, India
| | - Suneel Kumar Onteru
- Animal Biochemistry Division, National Dairy Research Institute, ICAR-NDRI, Karnal, Haryana, 132001, India
| | - Haseen Ahmad
- Animal Biochemistry Division, National Dairy Research Institute, ICAR-NDRI, Karnal, Haryana, 132001, India
| | - Raghvendar Singh
- Molecular Physiology Laboratory, Division of Physiology and Biochemistry, Central Sheep and Wool Research Institute, ICAR-CSWRI, Avikanagar, Rajasthan, 304501, India
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