Use of degenerate primers in rapid generation of microsatellite markers in Panicum maximum

Guineagrass (Panicum maximum Jacq.) is an important forage grass of tropical and semi-tropical regions, largely apomictic and predominantly exist in tetraploid form. For molecular breeding work, it is prerequisite to develop and design molecular markers for characterization of genotypes, development of linkage map and marker assisted selection. Hence, it is an important researchable issue to develop molecular markers in those crops where such information is scanty. Among many molecular markers, microsatellites or simple sequence repeat (SSR) markers are preferred markers in plant breeding. Degenerate primers bearing simple sequence repeat as anchor motifs can be utilized in rapid development of SSR markers; however selection of suitable degenerate primers is a prerequisite for such procedure so that SSR enriched genomic library can be made rapidly. In the present study seven degenerated primers namely KKVRVRV(AG)10, KKVRVRV(GGT)5, KKVRVRV(CT)10, KKVRVRV(AAT)6, KKVRVRV(GTG)6, KKVRVRV(GACA)5, and KKVRVRV(CAA)6 were used in amplification of Panicum maximum genomic DNA. Primers with repeat motifs (GGT)5 and (AAT)6 have not reacted whereas (AG)10, (GACA)5 and (CAA)6 highly informative as they have generated many DNA fragments ranging from 250 to 1600 bps as revealed from the results obtained with restriction digestion of recombinant plasmids. Primer with (CT)10 anchor repeat, amplified fragments of high molecular weight where as (GTG)6 primer generated only six bands with low concentration indicating less suitability of these primerin SSR markers development in P maximum.     

Uptake and accumulation of potentially toxic metals (Zn, Cu and Pb) in soils and plants of Durgapur industrial belt

Uptake and accumulation of metals in crops may cause possible health risks through food chain. A field survey was conducted to investigate the accumulation of potentially toxic metals contamination in soil and plants irrigated with complexed industrial effluents. Concentration of Zn, Cu and Pb was 205-255,101-130,118-177 microg g(-1) in rhizosphere soils and 116-223, 57-102 and 63-95 microg g(-1) d. wt. in root and 95-186, 44-75 and 27-58 microg g(-1) d. wt. in shoot, respectively. The trend in Cu and Pb was in the order: soil > root > shoot > seed while in Zn it was soil > root > seed > shoot. Roots accumulated a larger fraction of soil Cu (70%) > Zn (67%) > Pb (54%). Bioaccumulation coefficient of soil to root ranged from 51-98 for Zn, 54-85 for Cu and 43-63 for Pb.Analysis of variance showed marginal change in bioaccumulation coefficient, noticed between plants (p > 0.05) while it varied significantly (p < 0.01) between tissues and metals. It increased from root to seed/fruit (root > shoot > seed/fruit) while decreased between metals from Zn to Pb (Zn > Cu > Pb). Out of the three, two Cu and Pb accumulated to phyotoxic levels while Zn was within threshold limit of phytotoxicity.     

Nanoparticles in mitigating gaseous emissions from liquid dairy manure stored under anaerobic condition

A number of mitigation techniques exist to reduce the emissions of pollutant gases and greenhouse gases(GHGs) from anaerobic storage of livestock manure. Nanoparticle(NP)application is a promising mitigating treatment option for pollutant gases, but limited research is available on the mode of NP application and their effectiveness in gaseous emission reduction. In this study, zinc silica nanogel(ZnSNL), copper silica nanogel(CuSNL), and N-acetyl cysteine(NACL) coated zinc oxide quantum dot(Qdot) NPs were compared to a control lacking NPs. All three NPs tested significantly reduced gas production and concentrations compared to non-treated manure. Overall, cumulative gas volumes were reduced by 92.73%–95.83%, and concentrations reduced by 48.98%–99.75% for H_2S, and 20.24%–99.82% for GHGs. Thus, application of NPs is a potential treatment option for mitigating pollutant and GHG emissions from anaerobically stored manure.     

Carbon, nitrogen, and phosphorus budget in scampi (Macrobrachium rosenbergii) culture ponds

Experiments were conducted for the study of nutrient budget in ten farmer's ponds (0.2–0.5 ha) in Orissa, India with a mean water depth of 1.0–1.2 m. Scampi (Macrobrachium rosenbergii) were stocked in these ponds at stocking density of 3.75–5.0/m². The average initial body weight of scampi was 0.02 mg. The culture period was for 4 months. Feed was the main input. Total feed applied to these ponds ranged from 945 to 2261 kg pond/cycle (crop). The feed conversion ratio varied 1.65 to 1.78. In addition to feed, rice straw, urea, and single super phosphate were applied to these ponds in small amounts for plankton production. At harvest time, the average weight of scampi varied from 60–90 g. The budget showed that feed was the major input of nitrogen (N), phosphorus (P), and carbon in these ponds. The inorganic fertilizer (urea and single super phosphate), organic fertilizer (rice straw and yeast extract), and inlet water, either from the initial fills or from rainwater, were the source of all other N, P, and organic carbon (OC) to these ponds. Total N applied to these ponds through all these inputs ranged from 44.45 to 103.98 kg N per crop, 12.23 to 28.79 kg P per crop, and from 381.54 to 905.22 kg OC per crop, respectively. Among all the inputs, feed alone accounted for 95.34 % N, 97.98 % P, and 94.27 % OC, respectively. Recovery of 16.34 to 38.66 kg N (average 29.27 kg), 1.28 to 3.02 kg P (average 2.29 kg), and 63.21 to 149.51 kg OC (average 113.20 kg), respectively, by the scampi harvest were observed in these ponds. Thus, harvest of scampi accounted for recovery of 35.18 to 39.01 (average 36.85 %) of added N, 10.09 to 10.97 (average 10.44 %) of added P, and 7.57 to 17.12 (average 16.34 %) of added OC, respectively.     

Micronucleus induction by oxidative metabolites of trichloroethylene in cultured human peripheral blood lymphocytes: a comparative genotoxicity study

The genotoxic effects of oxidative metabolites of trichloroethylene (TCE), namely chloral hydrate, trichloroacetic acid (TCA), dichloroacetic acid (DCA), and trichloroethanol (TCEOH) were examined in human peripheral blood lymphocytes. In this context, lymphocytes were exposed in vitro to 25, 50, and 100 μg/ml concentrations of these metabolites separately for a period of 48 h and examined for micronucleus (MN) induction through flow cytometer. At 50 μg/ml TCE metabolites, TCA (6.33?±?0.56 %), DCA (5.06?±?0.55), and TCEOH (4.70?±?1.73) induced highly significant (p?<?0.001) frequency of MN in comparison to control (1.03?±?0.40) suggestive of their genotoxic potential. However, exposure of 100 μg/ml of all the metabolites consistently declined the frequencies of MN which in some cases was equable to that of observed at 25 μg/ml. Further, cytotoxicity and cell cycle disturbances were also measured to find out the association of these endpoints with the MN induction. DNA content analysis revealed 3–4-fold elevation of S-phase at all the concentrations tested. Particularly, at 100 μg/ml, treatment elevation of S-phase was significantly (p?<?0.0001) higher as compared to the control. Present findings together with earlier reports indicate that TCE induces genotoxicity through its metabolites. Interaction of these metabolites with DNA, as evident by elevated S-phase, seems to be the major cause of MN induction. However, involvement of spindle disruption cannot be ruled out. This comparative study also suggests that after TCE exposure, the metabolic efficiency of human to generate oxidative metabolites determines the extent of genotoxicity.