Browsing by Author "S. Sharma"

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Annual variation of plasma melatonin following pinealectomy and melatonin administration in Indian tropical rodent, Funambulus pennanti
(2004) C. Haldar; S. Sharma; S.S. Singh
Pinealectomy (Px) and melatonin (Mel) administration is known for its effect on reproductive and behavioural rhythms. To date no report is available to suggest the effect of Px and Mel administration on the annual variations of plasma Mel itself in any tropical seasonally breeding rodent. We report here that a statistically significant annual oscillation of Mel existed in sham operated control squirrel, F. pennanti. The exact peak value of Mel was noted some time in November (∼13th ± 8 days), which was certainly due to short photoperiod and low ambient temperature. Px decreased the melatonin level most significantly. Mel injection to Px squirrel entrained the phase of Mel, though the amplitude was not completely achieved but had a peak melatonin concentration in January (∼2 months phase delay). Exogenous Mel administration to sham operated squirrel decreased amplitude of melatonin during the months of March-July leading to early gonadal regression but could not alter the amplitude of Mel in November and December, while the peak value was phase delayed by ∼2 months (January). We may suggest, therefore, that the pineal gland of this squirrel is essential for maintaining its own rhythm, which is an adaptive significance of this tropical rodent for the perpetuation of the species. © VSP 2004.
Antibody responses of Wuchereria bancrofti patients to recombinant Brugia pahangi superoxide dismutase
(2001) S. Rathaur; S. Sharma; R.N. Singh; K. Henkle; M.E. Selkirk
Lymphatic filarial parasite Brugia malayi contains significant amount of Cu/Zn superoxide dismutase (SOD) activity in the extract of different life stages and in the excretory-secretory product of adults. In the present study recombinant SOD from B. pahangi has been used to see the antibody response in Wuchereria bancrofti infected patients. The recombinant SOD from B. pahangi reacted specifically with W. bancrofti infected sera in ELISA and immunoblotting. The reactivity of IgM subclass was more as compared to IgG subclass both in the asymptomatic microfilaraemic and symptomatic amicrofilaraemic when tested by ELISA. Serum from other helminthic infection was very low and found to be insignificant. The antibody response to rec SOD was directly proportional to the number of microfilariae in infected patients. The circulating filarial SOD was detected in filarial patients using polyclonal antibodies raised against recombinant Cu/Zn SOD in rabbits. The apparent molecular masses as determined by immunoblotting were 29 and 22 kDa. The specificity of recombinant SOD could be explored for its use in immunodiagnosis of lymphatic filariasis.
Bancroftian filariasis in the Varanasi region of north India: An epidemiological study
(1999) S. Sharma; M. Sharma; S. Rathaur
The age- and sex-specific distributions of human infections with Wuchereria bancrofti were investigated at two sites in the Varanasi region of north India: one a rural, agricultural area (Chiraigaon) and the other an urban-slum area (Sunderpur). A random clinical and parasitological survey revealed that the prevalence of microfilaraemia and elephantiasis in the urban area (14% and 7.3%, respectively) were both higher than in the rural area (9% and 3.1%, respectively). In both areas, prevalence of microfilaraemia generally increased with age, to a maximum in those aged 20-29 years, and then declined. Within most age-groups, the prevalences of microfilaraemia and elephantiasis were higher in males than females. However, the prevalence of microfilaraemia in females from Chiraigaon who were aged > 30 years was higher than in their male counterparts. Though individual microfilarial intensities varied greatly, the geometric mean microfilarial intensity was higher in Sunderpur than in Chiraigaon (214 v. 196 microfilariae/ml). All 83 subjects with elephantiasis, except one in Sunderpur, were amicrofilaraemic. The present results indicate that bancroftian filariasis is one of the major public-health problems in the study area.
Biochemical, gas exchange, and chlorophyll fluorescence analysis of maize genotypes under drought stress reveals important insights into their interaction and homeostasis
(Institute of Experimental Botany, ASCR, 2022) G.M. Singh; S. Goldberg; D. Schaefer; F. Zhang; S. Sharma; V.K. Mishra; J. Xu
Many studies have been conducted on maize to study the effect of drought on yield at the flowering stage, but understanding biochemical and photosynthetic response against drought at the seedling stage needs to be well established. Thus, to understand differential changes and interaction of biochemical and photosynthetic parameters at the seedling stage under drought, a greenhouse experiment with twelve maize genotypes under severe drought (30% field capacity) and irrigated (90–100% field capacity) conditions were performed. Drought differentially altered biochemical and photosynthetic parameters in all genotypes. A sharp increase in hydrogen peroxide, malondialdehyde (MDA), and total antioxidant capacity (TAOC) were seen and a positive association between H2O2 and TAOC, and MDA and transpiration rate (E) was observed under drought. Nonphotochemical quenching increased under drought to avoid the photosystem damage. PCA biplot analysis showed that reducing E and increasing photosynthetic efficiency would be a better drought adaptation mechanism in maize at the seedling stage. © The authors.
Development of somaclonal variants of wheat (Triticum aestivum L.) for yield traits and disease resistance suitable for heat stressed and zero-till conditions
(2007) B. Arun; B.D. Singh; S. Sharma; R. Paliwal; A.K. Joshi
In a substantial rice-wheat cropping system area of South Asia, wheat sowing often gets too delayed and exposed to terminal heat stress. Therefore, farmers prefer varieties that are able to perform well under a short growing period. Tissue culturally regenerated plants of wheat variety cv. HUW 234, the most widely cultivated variety of North Eastern Plain Zone (NEPZ) of India were screened using immature embryo as explant. Days to heading and maturity, yield and other yield components and resistance to leaf rust and spot blotch were evaluated. A few somaclones in R3 and R4 generations displayed significant earliness for days to heading and maturity, improved yield traits and resistance to leaf rust and spot blotch diseases. The superior performance of two of the variants was confirmed in the R5 generation in 3 years of testing under two dates of conventional and zero-till sowing. Stability analysis also suggested superiority of the two somaclones across 12 environments. This appeared to confirm the possibility of obtaining useful somaclonal variants of wheat for very late sown as well as zero-till managed agriculture. The superior performing somaclones can be used as parents in the ongoing breeding programmes targeting late sown wheat in South Asia exposed to terminal heat stress. © 2007 Elsevier B.V. All rights reserved.
Diversity in Indian barley (Hordeum vulgare) cultivars and identification of genotype-specific fingerprints using microsatellite markers
(Springer India, 2013) S.K. Jaiswal; Shree P. Pandey; S. Sharma; R. Prasad; L.C. Prasad; R.P.S. Verma; Arun K. Joshi
[No abstract available]
Diversity in Indian barley (Hordeum vulgare) cultivars and identification of genotype-specific fingerprints using microsatellite markers.
(2010) S.K. Jaiswal; Shree P Pandey; S. Sharma; R. Prasad; L.C. Prasad; R.P. Verma; Arun K Joshi
[No abstract available]
Esophageal atresia with tracheo-esophageal fistula: Role of nebulized N-acetylcysteine in the outcome
(2009) A. Pandey; A.N. Gangopadhyay; S. Sharma; V. Kumar
[No abstract available]
Evaluation of extractability of different extractants for zinc and copper in soils under long-term fertilization
(Institute of Agricultural and Food Information, 2015) Amit Kumar Pradhan; K.S. Beura; R. Das; D. Padhan; G.C. Hazra; B. Mandal; N. De; V.N. Mishra; K.B. Polara; S. Sharma
We aimed to evaluate the extractability of different extractants for zinc (Zn) and copper (Cu) in soils of long-term field experiments covering different agro-ecological zones of India. The relationships between the amounts of Zn and Cu extracted by Mehlich 3, 0.1 mol/L HCl and AB-DTPA (ammonium bicarbonate-diethylenetriaminepentaacetic acid) with those extracted by DTPA, the conventional extraction method widely used in soil testing laboratories in India, were elucidated. The treatments of the long-term experiments included control (no fertilizer), 100% NPK, 50%NPK + 50% N through FYM (farm yard manure) and a fallow soil. Some important physico-chemical properties of soil like pH, organic carbon, textural class, CaCO 3 content, etc. were analyzed. The NPK + FYM treatment was found to be the most effective treatment in terms of increased content of Zn and Cu in soils. The results showed that the amount of Zn and Cu extracted by Mehlich 3 were significantly correlated with that extracted by 0.1 mol/L HCl (r = 0.970** for Zn and r = 0.914** for Cu). Accordingly, Mehlich 3 and 0.1 mol/L HCl could be used effectively for estimating Zn and Cu availability in soils of India. However, Mehlich 3 was superior to all the other extractants used for the study. © 2015, Institute of Agricultural and Food Information. All rights reserved.
Expression profile of kisspeptin2 and gonadotropin-releasing hormone2 mRNA during photo-thermal and melatonin treatments in the female air-breathing catfish Heteropneustes fossilis
(Springer Science and Business Media B.V., 2020) R. Chaube; S. Sharma; B. Senthilkumaran; S.G. Bhat; K.P. Joy
In seasonally breeding vertebrates, extrinsic factors like photoperiod and temperature are major determinants, controlling the annual reproductive cycle. In teleosts, kisspeptin, which occurs in two molecular forms: kisspeptin1 (Kiss1) and kisspetin2 (Kiss2), has been reported to alter gonadotropin (Lh and Fsh) secretion but its effect on gonadotropin-releasing hormone (Gnrh) secretion is not unequivocally proved. In the catfish Heteropneustes fossilis, we isolated and characterized kiss2 and gnrh2 cDNAs and the present work reports effects of altered photo-thermal conditions and melatonin (MT, a pineal hormone) on their expressions in the brain. The exposure of the catfish to long photoperiod (LP, 16 h light) at normal temperature (NT) or high temperature (HT, 28 °C) at normal photoperiod (NP) for 14 or 28 days stimulated both kiss2 and gnrh2 expression in both gonad resting and preparatory phases with the combination of LP + HT eliciting maximal effects. Short photoperiod (SP, 8 h light) under NT or HT altered the gene expression according to the reproductive phase and temperature. MT that mediates photo-thermal signals to the brain inhibited brain kiss2 and gnrh2 gene expression in the NP + HT, LP + NT, and SP + NT groups. The altered photo-thermal conditions elicited changes in steroidogenic pathway as evident from changes in plasma E2, progesterone, and testosterone levels. The results show that brain kiss2-gnrh2 signaling is involved in photo-thermal-mediated mechanisms controlling reproduction. © 2020, Springer Nature B.V.
Extractable iron and manganese in soil as influenced by management practices in some long-term experiments of India
(IndianJournals.com, 2018) A.K. Pradhan; K.S. Beura; R. Das; D. Padhan; G.C. Hazra; B. Mandal; N. De; V.N. Mishra; S. Sharma; K.B. Polara
[No abstract available]
Functionalized ormosils-based biosensor. Probing a horseradish peroxidase-catalyzed reaction
(2003) P.C. Pandey; S. Upadhyay; S. Sharma
We report herein the electrochemistry of redox materials encapsulated with organically modified sol-gel glasses (ormosil). The ormosils that encapsulated ferrocene monocarboxylic acid and potassium ferricyanide are made using palladium-linked 3-glycidoxypropyltrimethoxysilane, trimethoxysilane, HCl, and an aqueous solution of potassium ferricyanide or ferrocene monocarboxylic acid followed by gelation of the same for 24 h at 30°C. The requirement of palladium linkage with ormosil is also examined and data on the electrochemistry of (i) only potassium-ferricyanide encapsulated ormosil without palladium, (ii) potassium-ferricyanide encapsulated ormosil with varying concentrations of palladium are reported. The ormosil made with optimum concentrations of palladium shows better redox electrochemistry as compared to that made without palladium. The ormosils are converted into fine powder followed by incorporation together with horseradish peroxidase within a graphite paste electrode. The peroxide biosensors based on modified-paste electrodes are characterized by cyclic voltammetry and chronoamperometry. Results on electrochemical sensing of hydrogen peroxide close to the cathode peak potential of potassium ferricyanide and ferrocene monocarboxylic acid are reported. The performance of these peroxide biosensors is discussed and compared to those reported earlier.
Green Nanomaterials for a Sustainable Future Environment
(Apple Academic Press, 2024) Anandkumar Naorem; A. Patel; A. Bhaguna; S. Sharma; A. Singh; N. Priya; P.H. Chanu; R. Patel; P. Singh; M. Jaison; B. Sahu; G. Sahu; S.K. Udayana
Nanotechnology has been widely applied in several areas including fertilization, environmental remediation, chemical industry power generation, etc. However, the increasing use of novel nanomaterials has also increased the concern of possible human health and environment-related threats. Therefore, green nanomaterials are developed using an environmentally benign process to reduce these risks associated with long-term use of nanomaterials in the environment. There is a recognized body of literature that highlights the use of algae, plants, fungi, bacteria, and even viruses to construct affordable, energy-efficient, and nontoxic nanomaterials. These green nanomaterials can be explored to manage, mitigate, or remediate soil water and air pollution or to improve the conventional technologies. With low energy consumption during the synthesis of green nanomaterials, it is expected to solve a part of environmental issues with the application of green nanotechnology. This chapter addresses the applications and limitations of green nanomaterials in light of sustainability and cleaner future environment. © 2024 Apple Academic Press, Inc.
Identification of kisspeptin2 cDNA in the catfish Heteropneustes fossilis: Expression profile, in situ localization and steroid modulation
(Academic Press Inc., 2020) R. Chaube; S. Sharma; B. Senthilkumaran; S.G. Bhat; K.P. Joy
Kisspeptin (Kiss) is considered an upstream regulator of gonadotropin-releasing hormone in mammals but its role in non-mammalian vertebrates is not unequivocally established. In the catfish Heteropneustes fossilis, a 605 bp long cDNA was identified from the brain by cloning as well as by retrieving from the catfish transcriptome database. The open reading frame (ORF, 93–405 bp) codes for a 113 amino acids long precursor protein. Homology and phylogenetic analyses showed that the predicted protein belongs to the vertebrate Kiss2 type with a high degree of conservation in the Kiss2-10 region (FNFNPFGLRF). The kiss2 transcripts were expressed highly in the brain and gonads in a dimorphic manner with a female bias. In the brain, kiss2 transcripts showed regional differences with higher expression in the medulla oblongata and forebrain regions. The kiss2 transcripts showed significant seasonal variations with the highest expression in the brain in spawning phase and in the gonads in prespawning phase. The kiss2 transcripts were localized in the brain (nucleus preopticus, habenular nucleus, nucleus recessus posterioris, nucleus recessus lateralis) and stratum periventriculare (radial glial cells) of optic tectum, pituitary and ovary (follicular layer and germinal vesicle). Ovariectomy (1, 2, 3 and 4 weeks) decreased brain kiss2 mRNA levels and a single injection of estradiol-17β (E2; 0.5 μg/g body weight) in 3- week ovariectomized (OVX) and sham operated fish resulted in an increase in the transcript levels after 24 h. The E2 receptor antagonist Tamoxifen (TMX) produced biphasic effects on the kiss2 expression in the dose- response study. TMX inhibited the expression in the OVX fish, but elicited a stimulatory effect in the OVX + E2-treated fish. Testosterone (T) decreased, and progesterone (P4) inhibited (resting phase) or stimulated (prespawning phase) the transcript level in 3-week OVX fish. In the 3-week sham groups, E2 increased, and TMX, T and P4 inhibited the kiss2 transcript levels. The results suggest that Kiss2 is an important regulator of the brain- pituitary- gonadal- endocrine axis, and in habenular and optic tectum functions. © 2020 Elsevier Inc.
Identification of molecular marker and aggressiveness for different groups of Bipolaris sorokiniana isolates causing spot blotch disease in wheat (Triticum aestivum L.)
(2007) S.K. Jaiswal; Sweta; L.C. Prasad; S. Sharma; S. Kumar; R. Prasad; S.P. Pandey; R. Chand; A.K. Joshi
One hundred fifty-five isolates of Bipolaris sorokiniana of wheat were studied for their morphopathological characterization. These isolates were grouped in five categories-black, brown/dull black, gray cottony growth, dull white/greenish black, and white-on the basis of their growth pattern. The frequency of the black suppressed type was maximum (45.63%), whereas the white isolate displayed lowest frequency (6.96%) in the natural population. Twenty RAPD (random amplified polymorphic DNA) primers were used to observe the variability among the identified groups of B. sorokininana. From each group, eight random isolates were investigated. A total of 143 bands were amplified, out of which 107 (74.83%) were polymorphic and 36 (25.17%) were monomorphic. On an average, the total numbers of bands generated per primer were 7.15, of which 5.35 and 1.80 were polymorphic and monomorphic, respectively. Dendrograms based on molecular polymorphism unveiled a considerable amount of diversity among the isolates. Specific DNA bands were identified for selected isolates. The distinct markers appeared to be potential enough to be employed as genetic fingerprints for future strain identification and classification. The study indicated that the RAPD primers provide an easy, rapid, and simple technique for the preliminary assessment of genetic diversity among the fungal isolates. © 2007 Springer Science+Business Media, LLC.
INFLUENCE OF THE DURATION OF DIABETES AND VIBRATION PERCEPTION THRESHOLD ON THE SEVERITY OF ERECTILE DYSFUNCTION IN PATIENTS WITH TYPE 2 DIABETES MELLITUS
(Acta Endocrinologica Foundation, 2022) P. Singh; S. Arora; A. Goyal; N. Mittal; A. Singh; S. Sharma; D.M. Shanthaiah; I.K. Dardi
Background. Erectile dysfunction(ED) in men is a frequent under-reported complication of diabetes mellitus, which is becoming significant health problem worldwide. Aims. The study aims to determine the prevalence and risk factors for development of ED in North Indian patients with type 2 diabetes mellitus. Methods. We used international index of erectile function (IIEF-5) for the assessment of ED in 796 patients with type 2 diabetes mellitus. We recorded the age, duration of diabetes, glycemic status, body mass index, diabetes medications, microvascular and macrovascular complications. Results. The mean age of patients in the study was 49.38 ± 9.52 years. The prevalence of ED in patients with type 2 diabetes mellitus was 79.4%. Logistic regression analysis revealed that age, body mass index, glycemic control, insulin therapy, retinopathy and nephropathy was not significantly associated with erectile dysfunction in patients with type 2 diabetes mellitus. Duration of diabetes (OR = 1.054, 95% CI 1.007 to 1.102, P=0.023) and vibration perception threshold (OR = 1.071, 95% CI 1.042 to 1.102, P=0.000) were identified as key risk factors for development of ED. Conclusion. Duration of diabetes and peripheral neuropathy emerged as significant risk factors for development of severe erectile dysfunction. © 2022, Acta Endocrinologica Foundation. All rights reserved.
Juvenile polyposis syndrome
(2008) Vijai Upadhyaya; A. Gangopadhyaya; S. Sharma; S. Gopal; D. Gupta; Vijayendra Kumar
Aim: Report of a series of 12 cases of juvenile polyposis coli. Methods: The study period was from 1995 to 2005. All the patients were treated by total colectomy with rectal mucosectomy and endorectal ileoanal pullthrough with or without ileal pouch formation. Covering ileostomy was avoided in all the cases. Time taken for the surgery, postoperative complications and continence were documented. Results: The mean operating time was 4.2 h (range: 4-5 h). The mean duration of hospital stay was 16.3 days (range: 15-18 days). The most common postoperative complication was pouchitis and perianal excoriation. Initially, all the patients were passing stools at an interval of 2 h, and after 3 weeks, the frequency has reduced to 6-8 stools per day. In the follow-up after 3 months, the frequency was 3-5 per day with minimal soiling. Conclusions: Single-stage total colectomy with rectal mucosectomy and endorectal ileoanal pull-through without covering ileostomy and pouch formation is a safe and definitive treatment for juvenile polyposis coli if the patient selection is appropriate.
Kisspeptins stimulate the hypothalamus - pituitary - ovarian axis and induce final oocyte maturation and ovulation in female stinging catfish (Heteropneustes fossilis): Evidence from in vivo and in vitro studies
(Elsevier B.V., 2022) R. Chaube; S. Sharma; B. Senthilkumaran; S.G. Bhat; K.P. Joy
In the present study, effects of synthetic human Kisspeptin1 (hKiss1) and catfish Kisspeptin2 (cfKiss2) on the hypothalamic - pituitary - ovarian (HPO) axis, and induction of final oocyte maturation and ovulation were investigated in prespawning female stinging catfish (Heteropneustes fossilis) under in vivo and in vitro conditions. Gene expression was quantified by real time quantitative PCR and steroids were measured by specific enzyme-linked immunoassays. Intraperitoneal (ip) injections (1, 2, 3 ng/g body weight, BW) of synthetic hKiss1 and cfKiss2 stimulated hypothalamic, pituitary and ovarian gnrh1 and gnrh2 expression at 24 h and the effect was higher after the cfKiss2 treatment. In vitro incubation of hypothalamus, pituitary and ovary pieces with the Kiss peptides (5, 10, 20 nM) produced a similar effect. GPR54 (Kiss1 receptor) antagonist peptide234, when given ip (5, 10, 20 ng/g BW) or incubated in vitro (5, 10, 20 nM), inhibited the gnrh1 and gnrh2 expression at 24 h. The supplementation with hKiss1 or cfKiss2 restored the inhibition due to peptide234 in vivo and in vitro and the effect was higher in the cfKiss2 combination group. Both hKiss1 and cfKiss2 altered the expression of pituitary gonadotropin (Gth) subunit genes follicle-stimulating hormone β (fshβ), luteinizing hormone β (lhβ) and glycoprotein α (gpα) in vivo and in vitro. The expression of fshβ was more sensitive to the treatments than lhβ expression and the effect was greater in the cfKiss2 groups. Peptide234 in vivo and in vitro inhibited the expression of the Gth genes and the effect was reversed and restored in the hKiss1 and cfKiss2 combination groups. The Kiss peptide treatments in vivo or in vitro stimulated both plasma and ovarian levels of estradiol-17β, progesterone and 17,20β-dihydoxy-4-pregnen-3-one levels. The peptide234 treatment inhibited, or elicited a decreasing trend on the steroid levels both in vivo and in vitro, and the inhibition was reversed by the hKiss1 and cfKiss2 combination treatments. Incubation of post vitellogenic follicles with hKiss1 or cfKiss2 stimulated germinal vesicle breakdown (GVBD) and ovulation. The inhibition due to peptide234 was reversed in the combination groups. Ovulation was not elicited or unaffected in the peptide234 treated groups. The data show that the Kiss peptides act downstream the HPO axis to stimulate oocyte maturation and ovulation, and cfKiss2 peptide is functionally more effective than hKiss1. © 2021 Elsevier B.V.
Long-term melatonin administration attenuates low-LET γ-radiation- induced lymphatic tissue injury during the reproductively active and inactive phases of Indian palm squirrels (Funambulus pennanti)
(2010) S. Sharma; C. Haldar; S.K. Chaube; T. Laxmi; S.S. Singh
A comparative analysis of low linear energy transfer (LET) γ-radiationinduced damage in the lymphatic tissue of a tropical seasonal breeder, Indian palm squirrel (Funambulus pennanti), during its reproductively active phase (RAP) and inactive phase (RIP) was performed with simultaneous investigation of the effects of long-term melatonin pre-treatment (100 mg/100 g body weight). A total of 120 squirrels (60 during RAP and 60 during RIP) were divided into 12 groups and sacrificed at 4, 24, 48, 72 and 168 h following 5 Gy c-radiation exposure; control groups were excluded fromexposure. Total leukocyte count and absolute lymphocyte count (ALC) and melatonin only of peripheral blood, stimulation index, thiobarbituric-acid-reactive substances (TBARS) level, superoxide dismutase (SOD) activity, and the apoptotic index of spleen as analysed by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labelling (TUNEL) noted at observed time-points were significantly reduced in melatonin pre-treated groups during RAP and RIP. Long-term melatonin pretreatment mitigated radiation-induced alterations more prominently during RIP, as assessed by ALC, TBARS, SOD, TUNEL and caspase-3 activity, at some time-points. Our results demonstrate an inhibitory role of melatonin on caspase-3 activity in splenocytes during RAP and RIP following γ-radiation-induced caspase-mediated apoptosis. Hence, we propose that melatonin might preserve the viability of immune cells of a seasonal breeder against background radiation, which is constantly present in the environment. © 2010 The British Institute of Radiology.
Molecular cloning and characterization of a gonadotropin-releasing hormone 2 precursor cDNA in the catfish Heteropneustes fossilis: Expression profile and regulation by ovarian steroids
(Academic Press Inc., 2019) R. Chaube; A. Rawat; S. Sharma; B. Senthilkumaran; S.G. Bhat; K.P. Joy
Gonadotropin-releasing hormone 2 (Gnrh2) is one of the three classes of Gnrh distributed in vertebrates and is highly conserved. In the present study, the cDNA encoding Gnrh2 was isolated and characterized in the ostariophysan catfish Heteropneustes fossilis (hf). The cDNA is 611 bp long with an open reading frame (ORF) of 261 bp that encodes a highly conserved protein of 86 amino acids. The deduced Gnrh2 precursor protein clustered with the vertebrate Gnrh2 type. The sequence identity of hfgnrh2 is 94% with African catfish (Clarias gariepinus) gnrh2 mRNA (accession no. X78047). The hfgnrh2 transcripts were expressed only in the brain and gonads with a higher expression in the female brain and ovary in both resting and prespawning phases. The expression was higher in the prespawning phase than the resting phase. The gnrh2 expression in the brain and ovary showed significant seasonal variations but with opposite patterns. In the brain, the expression was the highest in the preparatory phase, decreased progressively to low levels in the postspawning and resting phases. In the ovary, the transcript level was low in the resting and preparatory phases, increased sharply in the prespawning phase reaching the peak level in the spawning phase and declined sharply in the postspawning phase. The gnrh2 mRNA showed the highest expression in the hind brain-medulla oblongata and moderate to low expression in forebrain regions and pituitary. Ovariectomy resulted in a duration-dependent inhibition of hfgnrh2 mRNA levels in the resting and prespawning phases. Steroid (E2, testosterone and progesterone) replacement treatments (0.5 μg/g body weight) in the 3- week ovariectomized fish restored the inhibition due to ovariectomy, elevated the expression over and above the sham level in the resting phase (E2 group), and raised the levels almost to that of the sham group (testosterone and progesterone groups) in the prespawning phase. In the sham control groups, the steroid replacement resulted in a significant reduction in the mRNA levels. The expression of the gnrh2 mRNA in the brain-pituitary-gonadal axis and its regulation by gonadal steroids suggest that Gnrh2 may have a reproductive role in the catfish. © 2019 Elsevier Inc.