title: Hypoxic stress -responsive genes in air breathing catfish, Clarias magur (Hamilton 1822) and their possible physiological adaptive function.
abstract: The Indian catfish, Clarias magur (previous name C. batrachus) is an air breathing fish, inhabitant of aquatic bodies characterized by low dissolved oxygen levels. It is exposed to hypoxic conditions in its natural habitat. Thus, it can be useful model to study the mechanism of hypoxia stress tolerance. In C. magur, molecular processes facilitating its adaptation to hypoxia stress remain largely unexplored, in part due to unavailability of genomic resources. The suppression subtractive hybridization technique (SSH) was employed to compare the differential expression of transcripts under experimental hypoxic conditions, to that of normoxic conditions. Twelve subtracted cDNA libraries (six each forward and reverse) were constructed from brain, heart, liver, muscle, spleen and head kidney tissues. A total of 2020 clones were screened and sequenced, resulting into 1805 high quality expressed sequence tags (ESTs). Annotation of these differentially expressed ESTs resulted into the identification of genes involved in vast majority of pathways/processes affecting metabolism, cellular processes, signal transduction and/or immune functions. Additionally, 18 potential novel genes expressed in hypoxia stress exposed fish were also identified. The study had catalogued the differentially expressed genes from hypoxia stress induced C. magur, where most of them are reported for the first time in a hypoxia-tolerant fish species. The results not only provided insights for the hypoxia stress altered cellular functions in C. magur, but also generated a valuable functional genomics resource to assist targeted studies on functional genomics and future genome projects.
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India. Electronic address: vindhyamohindra@gmail.com.
authors.forename: Vindhya
authors.initials: V
authors.lastname: Mohindra
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Ratnesh Kumar
authors.initials: RK
authors.lastname: Tripathi
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Akanksha
authors.initials: A
authors.lastname: Singh
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Patangia
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Rajeev Kumar
authors.initials: RK
authors.lastname: Singh
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Kuldeep Kumar
authors.initials: KK
authors.lastname: Lal
authors.affiliation: ICAR-National Bureau of Fish Genetic Resources, Canal Ring Road, P.O. Dilkusha, Lucknow 226002, Uttar Pradesh, India.
authors.forename: Joy Krushna
authors.initials: JK
authors.lastname: Jena
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000693:Anaerobiosis; D000818:Animals; D002397:Catfishes / Q000235:genetics* / Q000502:physiology; D020224:Expressed Sequence Tags; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling / Q000662:veterinary; D015723:Gene Library; D013312:Stress, Physiological / Q000235:genetics*; D066251:Subtractive Hybridization Techniques / Q000662:veterinary
chemical_list: D029941:Fish Proteins
keywords: Clarias magur; Differentially expressed genes; Hypoxia; SSH transcripts; Stress