Sensing and Uptake of Nitrogen in Rice Plant: A Molecular View

As a main feature of plant autotrophy, assimilation of inorganic nitrogen (N) is not only of fundamental interest to the crop, but also a crucial factor in crop productivity. N is the main plant mineral nutrient needed for chlorophyll production and other plant cell components (proteins, nucleic acids and amino acids). I highlighted the novel aspects of N responsive sensors, transporters and signaling molecules recently identified in the monocot rice plant, and discussed their potential roles in N sensing and transporting. Furthermore, over the last couple of years, N sensing has been shown to be affected by different external factors, which act as local signals to trigger systemic signaling coordinated by long-distance transport or mobile signals in plant body. Understanding of this complex regulatory network provides a foundation mechanism for the development of novel strategies to increase the acquisition and transportation efficiency of nitrogen under varying N conditions for rice production.

Antioxidant,antibacterial and cytotoxic effects of the phytochemicals of whole Leucas aspera extract

Objective:To investigate the antioxidant,antibacterial and cytotoxic activity of whole Leucas aspera(Labiatae)(L.aspera)alcoholic extract.Methods:Whole L.aspera powder was extracted by absolute ethanol(99.50%).The ethanolic extract was subjected to antioxidant,antibacterial and brine shrimp lethality assay.Results:The extract showed potent radical scavenging effect(antioxidant)with IC_(50)value of(99.58±1.22)μg/mL which was significant(P<0.01)in comparison to ascorbic acid with IC_(50)value of(1.25±0.95)μg/mL.In case of antibacterial screening,the extract showed notable antibacterial effect against the tested microbial strains.Significant(P<0.05)zone of inhibitions against Gram positive Bacillus subtilis[(12.00±1.32)mm]and Bacillus megaterium[(13.00±1.50)mm],Staphylococcus aureus[(8.00±0.50)mm]and Gram negative Salmonella typhi[(6.00±0.50)mm],Salmonella paratyphi[(8.00±1.00)mm],Shigella dysenteriae[(9.00±1.32)mm]and Vibrio cholerae[(9.00±0.66)mm]was observed.In brine shrimp lethality bioassay,the extract showed the LC_(50)value as(181.68±2.15)μg/mL which was statistically significant(P<0.01)compared to positive control vincristine sulfate[LC_(50)=(0.76±0.04)μg/mL].Conclusions:The results demonstrate that the ethanolic extract of L.aspera could be used as antibacterial,pesticidal and various pharmacologic actives.

Characterization and Laboratory-Scale Treatment of Municipal Drainage Wastewater of Khulna, Bangladesh

The study was conducted to characterize and perform laboratory-scale treatment of municipal drainage wastewater of Khulna, Bangladesh. Wastewater samples were collected from three different points of existing urban drain outlets into the Mayur River around Khulna. Laboratory testing shows the BOD5 and COD concentration of wastewater samples varied from 57 - 226 mg/l and 320 - 435 mg/l, respectively, and the total dissolved solids ranged from 1800 - 2525 mg/l. Therefore, a laboratory-scale treatment technology was developed to treat this wastewater. Treatment technologies adopted were primary sedimentation, followed by aeration, chemical precipitation and filtration. In treated wastewater, BOD5, COD and TDS were found to be in the range of 40 - 115 mg/l, 160 - 256 mg/l and 1356 - 1500 mg/l, respectively. These test results suggest that the performance of laboratory-scale treatment plant was not adequate to fulfil the acceptable limit (ECR’97) for safe disposal into surface water bodies. Due to poor quality of effluents, modification of laboratory-scale treatment plant was made by an activated sludge process followed by granular media filtration. The final BOD5, COD TDS and TSS concentration of effluents was found to be 1.38 - 9.8 mg/l, 32 - 192 mg/l, 590 - 1667 mg/l, and 35 - 95 mg/l respectively, which satisfy ECR’97 standard limits for safe disposal into inland water bodies.