Biological properties of Indian walking catfish (Clarias batrachus) (L.) gonadotropins in female reproduction     

Shrabanti Sarkar  Debapriya Bhattacharya  Subir Kumar Juin  Panchanan Nath 《Fish physiology and biochemistry》2014,40(6):1849-1861

The biological activities of catfish LH-like (semi-purified: s200a and purified Qa) and FSH-like (semi-purified: s200b and purified: Qb) were compared in intact and hypophysectomized female catfish, Clarias batrachus, during preparatory and the pre-spawning periods on vitellogenesis and ovarian maintenance, as well as in vitro final maturation of oocytes, germinal vesicle breakdown (GVBD). During preparatory period, in intact catfish, semi-purified FSH-like induced complete vitellogenesis through the production of estradiol-17β (E₂) and vitellogenin (Vg) accompanied by the formation of SIII yolky oocytes. On the other hand, semi-purified LH-like had induced the formation of only SII (characterized by the appearance of cortical alveoli in cytoplasm) oocytes, which indicates the initiation of vitellogenesis. In hypophysectomized female catfish, purified LH-like but not FSH-like induced the formation of SII oocytes in the ovaries. Treatment with semi-purified LH- and FSH-like at the dose level of 5 µg/fish/day for 7 days significantly maintained the yolky oocytes in gravid catfish after hypophysectomy with a significant reduction in plasma Vg, but not E₂ levels, indicating some unknown GtH-induced factor doing the job. In in vitro oocytes culture, both LH- and FSH-like induced GVBD, but the response was significantly more with LH-like than FSH-like. All these findings revealed that both LH-like and FSH-like have overlapping physiological functions, but their responses differ depending on the physiological status of the catfish.  相似文献   

Effect of cytolethal distending toxin of Campylobacter jejuni on adhesion and internalization in cultured cells and in colonization of the chicken gut     

Biswas D  Fernando U  Reiman C  Willson P  Potter A  Allan B 《Avian diseases》2006,50(4):586-593

Campylobacter jejuni produces cytolethal distending toxin (CDT) that causes host cells to arrest during their cell cycle and that is involved in the pathogenesis of inflammatory diarrhea in humans. To assess the role of CDT in adherence and invasion of different cultured host cells (HeLa and HD-11) and in colonization of the chicken intestine, the genes of C jejuni NCTC11168 encoding the toxin subunits (cdtA, cdtB, and cdtC) were inactivated by insertional mutagenesis. No significant difference was found in adhesion of the wild-type C. jejuni and the isogenic mutants to HeLa and HD-11 cells. All of the mutants exhibited a decrease (>10-fold) in the ability to invade HeLa cells, but no significant difference was noticed for HD-11 cells. The ability of mutants to colonize birds either directly or by horizontal transfer was unchanged. These data indicated that although the production of cytotoxin does not play a role in the adherence to either human or avian cells, it may play a role in the invasion, survival, or both of C. jejuni in human cells, which are more susceptible to C. jejuni internalization. The CDT also does not seem to play a role in the colonization of poultry.  相似文献   

Expression profile of HSP genes during different seasons in goats (Capra hircus)     

Satyaveer Singh Dangi  Mahesh Gupta  Divakar Maurya  Vijay Prakash Yadav  Rudra Prasanna Panda  Gyanendra Singh  Nitai Haridas Mohan  Sanjeev Kumar Bhure  Bikash Chandra Das  Sadhan Bag  Ramkrishna Mahapatra  Guttalu Taru Sharma  Mihir Sarkar 《Tropical animal health and production》2012,44(8):1905-1912

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Preliminary study on crystal dissolution activity of Rotula aquatica, Commiphora wightii and Boerhaavia diffusa extracts     

Raut AA  Sunder S  Sarkar S  Pandita NS  Vaidya AD 《Fitoterapia》2008,79(7-8):544-547

Several Ayurvedic plants are known to have activity against diverse urinary crystals. The traditional knowledge of Ayurveda, collective clinical experience in arthritis and the earlier experimental studies on urinary crystals led to the selection of three plants, viz. Rotula aquatica, Commiphora wightii Bhandari syn. C.mukul. and Boerhaavia diffusa for screening anticrystal activity against basic calcium phosphate (BCP), calcium pyrophosphate (CPPD) and monosodium urate monohydrate (MSUM). The effects of each plant were assayed on microcrystals in 24-well microplates in vitro. Our results show that the aqueous extracts of only R. aquatica and C. wightii have shown crystal dissolving activity against MSUM.  相似文献   

Effect of mulching on soil and plant water status, and the growth and yield of wheat (Triticum aestivum L.) in a semi-arid environment     

Debashis Chakraborty  Shantha Nagarajan  V.K. Gupta  R.N. Garg  A. Sarkar  K.S. Sundara Sarma 《Agricultural Water Management》2008,95(12):1323-1334

Mulching is one of the important agronomic practices in conserving the soil moisture and modifying the soil physical environment. Wheat, the second most important cereal crop in India, is sensitive to soil moisture stress. Field experiments were conducted during winter seasons of 2004-2005 and 2005-2006 in a sandy loam soil to evaluate the soil and plant water status in wheat under synthetic (transparent and black polyethylene) and organic (rice husk) mulches with limited irrigation and compared with adequate irrigation with no mulch (conventional practices by the farmers). Though all the mulch treatments improved the soil moisture status, rice husk was found to be superior in maintaining optimum soil moisture condition for crop use. The residual soil moisture was also minimum, indicating effective utilization of moisture by the crop under RH. The plant water status, as evaluated by relative water content and leaf water potential were favourable under RH. Specific leaf weight, root length density and dry biomass were also greater in this treatment. Optimum soil and canopy thermal environment of wheat with limited fluctuations were observed under RH, even during dry periods. This produced comparable yield with less water use, enhancing the water use efficiency. Therefore, it may be concluded that under limited irrigation condition, RH mulching will be beneficial for wheat as it is able to maintain better soil and plant water status, leading to higher grain yield and enhanced water use efficiency.  相似文献   

Citric acid loaded nano clay polymer composite for solubilization of Indian rock phosphates: a step towards sustainable and phosphorus secure future     

Trisha Roy  Samar Chandra Datta  Abhijit Sarkar  Siddhartha Sankar Biswas 《Archives of Agronomy and Soil Science》2018,64(11):1564-1581

Non-renewable nature of rock phosphate (RP) reserves coupled with open ended nature of P cycle makes it imperative for maximum utilization of available P resources. In this context, use of Indian RPs from Purulia and Udaipur along with citric acid loaded nanoclay polymer composite (CA-NCPC) as P source to costly diammonium phosphate (DAP) was investigated through an incubation experiment followed by a greenhouse experiment with wheat-rice cropping sequence in a Luvisol (pH 5.14, available P 13.5 mg kg^?1). Soil available P, crop yield parameters and dynamics of soil P fractions were taken to judge the efficacy of CA-NCPC in solubilizing RPs. Application of CA-NCPC and DAP resulted in 82% and 69% increase in available P over control, respectively under incubation study. Direct effect of treatment receiving CA-NCPC + RP on yield and P uptake by wheat was comparable with DAP but residual impact of CA-NCPC + RP (16.7 g pot^?1) was better than DAP (13.8 g pot^?1) in rice. The changes in inorganic P fractions were also significant as inclusion of RP increased calcium-P from 16.1 to 61.5 mg kg^?1. Results indicated potentiality of RPs treated with CA-NCPC as an alternate P source which could prove promising amidst P scarcity.  相似文献   

Projecting Future Crop Evapotranspiration and Irrigation Requirement of Potato in Lower Gangetic Plains of India using the CROPWAT 8.0 Model     

Saon Banerjee  S. Chatterjee  S. Sarkar  S. Jena 《Potato Research》2016,59(4):313-327

A study on evapotranspiration from potato fields was conducted in the Lower Gangetic Plains of India. The input data required for the CROPWAT irrigation management model was collected, and evapotranspiration (ET) and irrigation water requirement (IWR) for potato crops were calculated using the model. Firstly, the CROPWAT model was validated by comparing simulated crop evapotranspiration (SET) with actual ET calculated through the field water balance method. Thereafter, SET and IWR for nine locations in the lower Gangetic plains of India were calculated for the period from 1996–1997 to 2008–2009, for the current situation (using 20-year-average weather data of the stations), and for elevated thermal conditions, i.e. considering 2 and 3 °C increases over the current temperature. The future change in IWR for potato up to 2050 was also calculated considering the projected climatic scenario generated by the PRECIS model. The CROPWAT calculated IWR values showed an increasing, though not statistically significant, trend in requirement of irrigation water for potato across the nine locations during the period from 1996–1997 to 2008–2009. At a temperature increase of 2 °C over normal, the mean SET of potato would increase by 0.06 mm per day and the average IWR would be 6.0 mm per season more. If the mean temperature would be 3 °C more than normal, the SET would be 0.16 mm day^?1 higher and the IWR 16.6 mm. Also based on the projected climatic scenario generated by the PRECIS model, the future SET up to 2050 showed an increasing trend. The present study indicates increasing demand for irrigation water, which may significantly affect the agricultural scenario in the region.  相似文献   

<Emphasis Type="Italic">Fusarium</Emphasis> elicitor-dependent calcium influx and associated ros generation in tomato is independent of cell death     

Sanjukta Dey  Kaushik Ghose  Debabrata Basu 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(2):217-228

Fusarium oxysporum f. sp. lycopersici elicitor (EFOL-2) treatment induces cytosolic influx of calcium in Fusarium-resistant tomato suspension culture. The calcium signature was found to be biphasic, which is characteristic of recognition of oligosaccharides in the elicitor preparation. Further, several lines of evidence such as, (i) attainment of saturation level of the [Ca²⁺]_cyt at a definite extra-cellular calcium concentration (ii) prominent reduction in EFOL-2-induced influx in [Ca²⁺]_cyt on treatment with the calcium channel blockers verapamil and diltiazem and (iii) establishment of a refractory stage of [Ca²⁺]_cyt level upon repeated stimulation by EFOL-2, is indicative of receptor-mediated activation of the calcium channel for cytosolic elevation. In addition, inhibition of EFOL-2-induced [Ca²⁺]_cyt increase by protein kinase inhibitor staurosporine and wortmannin indicate phosphorylation is a regulatory event of calcium influx. Additionally, monitoring of cell death on EFOL-2 treatment indicated that the degree of ROS generation is not capable of inducing cell death. Inhibition of ROS generation on two separate occasions such as, calcium-free media and on treatment with inhibitors causing calcium channel occlusion revealed ROS generation as a successive event of calcium influx.  相似文献   

Measuring near‐saturated hydraulic conductivity of soils by quasi unit‐gradient percolation—1. Theory and numerical analysis     

Subharthi Sarkar  Kai Germer  Rajib Maity  Wolfgang Durner 《植物养料与土壤学杂志》2019,182(4):524-534

The saturated and near‐saturated hydraulic conductivity of soils, k_u, is a sensitive indicator of soil structure and a key parameter for solute transport and soil aeration. In this contribution, we present and numerically investigate a double‐disk method to determine k_u in the laboratory by steady‐state percolation at different suction steps. Tension infiltration of water takes place at the top of a soil column through a porous disk with a smaller diameter than the soil sample. This leaves part of the soil surface open and ensures a proper soil ventilation. Drainage takes place at the base through a porous disk with the full diameter of the soil column at exactly the same tension as applied to the top boundary. Since the infiltration area is less than the percolation area, the water flow diverges and the equality of steady flow rate and hydraulic conductivity, which characterizes the standard unit‐gradient experiment, is no longer valid. To develop a general relationship between observed steady flow rate and unsaturated hydraulic conductivity, the experiment was simulated with the Richards‐equation solver HYDRUS 2D/3D, for twelve different soil classes. We found for tensions in the range 1 cm < 10 cm, an infiltration disk diameter of 4.5 cm diameter and a sample diameter of 8 cm diameter that the flux rate at any given tension was about 0.7 times the respective hydraulic conductivity, with an error of less than 10%.  相似文献   

Effect of inorganic nitrogen nutrition on cytokinin-induced potato microtuber production in vitro   总被引：1，自引：1，他引：0  

Debabrata Sarkar  Prakash S. Naik 《Potato Research》1998,41(3):211-217

Summary The effect of inorganic nitrogen nutrition on the induction and development of microtubers by cytokinin-induced tuberization was studied in four potato genotypes belonging to different maturity groups. The objective of this study was to investigate whether a reduction in total nitrogen level in the Murashige & Skoog medium would improve cytokinin-induced tuberization rate. The effect of three levels of total nitrogen (15, 30 and 45 meq) on tuberization was studied at constant (20 meq K) and varying potassium levels approximating to 5, 10 and 15 meq. Reducing the total nitrogen supply increased the number but decreased the size of nitrogen level on the rate of assimilate partitioning (harvest index) during cytokinin-induced microtuberization.  相似文献