Phytoremediation Potential of Vetiver Grass (<Emphasis Type="Italic">Vetiveria zizanioides</Emphasis>) for Treatment of Metal-Contaminated Water

Phytoremediation using vetiver grass (Vetiveria zizanioides) has been regarded as an effective technique for removing contaminants in polluted water. This study was conducted to assess the removal efficiency of heavy metals (Cu, Fe, Mn, Pb, Zn) using vetiver grass (VG) at different root lengths and densities and to determine metals uptake rate by plant parts (root and shoot) between treatments (low and high concentration). Removal efficiency for heavy metals in water by VG is ranked in the order of Fe>Pb>Cu>Mn>Zn. Results showed that VG was effective in removing all the heavy metals, but removals greatly depend on root length, plant density and metal concentration. Longer root length and higher density showed greater removals of heavy metals due to increased surface area for metal absorption by plant roots. Results also demonstrated significant difference of heavy metals uptake in plant parts at different concentrations indicating that root has high tolerance towards elevated concentration of heavy metals. However, the effects were less significant in plant shoot suggesting that metals uptake were generally higher in root than in shoot. The findings have shown potential of VG in phytoremediation for heavy metals removal in water thus providing significant implication for treatment of metal-contaminated water.     

Polyphenolics Profile, Antioxidant and Radical Scavenging Activity of Leaves and Stem of Raphanus sativus L.

Aerial parts (leaves and stem) of Raphanus sativus, which are usually discarded were found to possess potent antioxidant and radical scavenging activity, as measured by standard antioxidant assays. Methanolic and acetone extracts of R. sativus leaves had total polyphenolic content of 86.16 and 78.77 mg/g dry extract, which were comparable to the traditional rich sources such as green tea and black tea. HPLC identification of polyphenolics indicated the presence of catechin, protocatechuic acid, syringic acid, vanillic acid, ferulic acid, sinapic acid, o-coumaric acid, myricetin, and quercetin in leaves and stem. Among the different extraction solvents, methanolic extract of leaves and stem showed potent reductive capacity, significantly inhibited linoleic acid peroxidation and displayed metal chelating activity. Further, they scavenged free radicals effectively with IC₅₀ (half maximal inhibitory concentration) of 31 and 42 μg/ml for DPPH radical, 23 and 52 μg/ml for superoxide radical, 67 and 197 μg/ml for hydrogen peroxide, and 56 and 62 μg/ml for nitric oxide, respectively. Leaves showed most potent antioxidant and radical scavenging activity as compared to stem, which may be accounted for the high polyphenolic content. Leaves and stem of R. sativus, often under-utilized part of this vegetable, thus possessed considerable amount of polyphenolics. Hence, it should be regarded as a potential source of natural antioxidants and could be effectively employed as an ingredient in health or in functional food.     

Efficacy of nine insecticides against shoot and fruit borer, <Emphasis Type="Italic">Leucinodes orbonalis</Emphasis> Guenee (Lepidoptera: Pyralidae) in eggplant

Shoot and fruit borer, Leucinodes orbonalis Guenee, is a serious pest of eggplant (Solanum melongena L.). Management practices of this obnoxious pest are limited to frequent spray of chemical insecticides. Due to increasing levels of resistance of L. orbonalis to different insecticides there is an urgent need to test new chemicals. In this study, nine insecticides such as azadirachtin 0.03EC, abamectin 1.8EC, flubendiamide 24WG, chlorpyriphos 20EC, cartap 50SP, carbosulfan 20EC, thiodicarb 75WP, cypermethrin 10EC, and lambdacyhalothrin 2.5EC belonging to different chemical groups were tested against eggplant shoot and fruit borer in laboratory and field. In laboratory trial, carbosulfan and flubendiamide showed the highest toxicity against fourth instar larvae of L. orbonalis after 24 and 48 h of exposure, respectively. In field trials, they reduced more than 80% shoot and fruit infestation in winter, and 80% shoot and 70% fruit infestation in summer over control. Carbosulfan protected the highest amount of healthy fruit yield in both cropping seasons. Flubendiamide also showed the similar efficacy. Cartap and thiodicarb were moderately effective in both the seasons. Efficacy of cypermethrin and abamectin was moderate in winter but low in summer. Lambdacyhalothrin and chlorpyriphos although reduced shoot and fruit infestation of eggplant and protected higher yield as compared to control, their effectiveness was not satisfactory. The performance of azadirachtin against the pest both in the laboratory and field trials was the poorest while that of carbosulfan and flubendiamide was the best. Thus, it is suggested that carbosulfan and flubendiamide may be used for the control of L. orbonalis in eggplant.     

DNA vaccine encoding avian influenza virus H5 and Esat-6 of Mycobacterium tuberculosis improved antibody responses against AIV in chickens

The H5 gene of avian influenza virus (AIV) strain A/chicken/Malaysia/5744/2004(H5N1) was cloned into pcDNA3.1 vector, and Esat-6 gene of Mycobacterium tuberculosis was fused into downstream of the H5 gene as a genetic adjuvant for DNA vaccine candidates. The antibody level against AIV was measured using enzyme-linked immunosorbent assay (ELISA) and haemagglutination inhibition (HI) test. Sera obtained from specific-pathogen-free chickens immunized with pcDNA3.1/H5 and pcDNA3.1/H5/Esat-6 demonstrated antibody responses as early as 2 weeks after the first immunization. Furthermore, the overall HI antibody titer in chickens immunized with pcDNA3.1/H5/Esat-6 was higher compared to the chickens immunized with pcDNA3.1/H5 (p < 0.05). The results suggested that Esat-6 gene of M. tuberculosis is a potential genetic adjuvant for the development of effective H5 DNA vaccine in chickens.     

Factors limiting traditional household duck production in Bangladesh

A cross sectional survey of duck production was carried out in 2002 on 771 traditional, semiscavenging household duck farms on the coastal Island of Hatia. We determined the socioeconomic characteristics of duck farmers and their management systems, identified the factors associated with egg production, and measured the level of selected duck diseases and current preventive strategies. Household family size varied from 1 to 14 individuals and women were the main caretakers of ducks. Around 34% of keepers were illiterate. Most duck products (eggs and meat; 85%) were sold at the local market. Duck houses were poorly ventilated and a variety of bedding materials were used. Feed was available in nearby scavenging areas; however, additional feed was frequently supplied by farmers. Almost all farmers (96%) ranked the rainy season as the best time for rearing ducks due to greater feed availability. The annual egg production was 79 eggs per layer with a weight of 48 g and a hatchability rate of 87%. Egg production varied by zone (p < 0.05). The odds of suboptimal egg production was 0.5 times lower in educated farmers (p = 0.001). The odds of suboptimal egg production was 2.5 times more likely in ducks that attained sexual maturity at >22 weeks (p<0.001). Most farmers ranked duck plague as the most important disease, followed by duck cholera, botulism, and duck viral hepatitis. Preventive vaccination was sporadic and used by few farmers (28%). There are significant opportunities for improved duck production on the Island of Hatia and in Bangladesh generally.     

In vitro plant regeneration system for <Emphasis Type="Italic">Cassia siamea</Emphasis> Lam., a leguminous tree of economic importance

A method for rapid in vitro propagation of Cassia siamea Lam. using cotyledonary node explants, excised from 14-day old aseptic seedlings, has been established. Murashige and Skoog (MS) medium supplemented with different concentrations of 6-benzyladenine (BA), kinetin (Kn) and thidiazuron (TDZ) singly or in combination with auxins was used for regeneration studies. Among the single treatment of three cytokinins BA at 1.0 μM was found to be optimum for direct shoot regeneration as it induced an average of 8.20 ± 0.66 shoots per explant. The regeneration frequency further enhanced with the application of auxin along with optimal BA concentration. The highest frequency for shoot regeneration (90%), the maximum number of shoots per explant (12.20 ± 0.73) and the maximum shoot length (6.40 ± 0.07) cm were obtained on the medium consisted of MS + 1.0 μM BA + 0.5 μM NAA. Successful in vitro rooting was induced from cut end of the microshoots when placed on half-strength MS + IBA (2.5 μM). The regenerated shoots with well developed root system were successfully acclimatized and established in pots containing sterilized garden soil and garden manure (1:1) and grown under greenhouse conditions with 85% survival rate.     

Changes in enzyme activities,soluble sugars and phenols during in vitro adventitious shoot regeneration from leaflet explants of <Emphasis Type="Italic">Albizia procera</Emphasis> (Roxb.) Benth

Changes in nitrate reductase, i.e. NR (E.C. 1.7.1.1) activity, peroxidase (E.C. 1.11.1.14) activity, soluble sugars and phenols were monitored at various time intervals from day 0 to 60 during in vitro adventitious shoot regeneration from leaflet explants of Albizia procera (Roxb.) Benth. The explants were incubated on semi-solid Murashige and Skoog medium supplemented with 2.6 g l^?1 Phytagel^®, 2.5% sucrose, 10 μM BAP, 1 μM NAA and 15 μM AgNO₃. NR activity, soluble sugars and phenols exhibited initial sharp rise on around day 20 followed by steep decline on day 25, whereas peroxidase activity peaked on day 50, highlighting significance of early input of nitrogen and energy and late emergence of lignification process for cellular differentiation and organization into adventitious shoot primordia. Morpho-anatomical changes in leaflets at various stages of in vitro adventitious shoot formation also followed the endogenous biochemical pattern.     

Ecological disturbances due to high cutback in the green infrastructure of Karachi: Analyses of public perception about associated health problems

This paper evaluates the changes to the green infrastructure of the megacity of Karachi, Pakistan, occurring during a period of rapid development, involving extensive loss of trees and green spaces since 2000, occurring as a consequence of road widening and improvements to the city's transport infrastructure, aggravated by a series of cyclones, involving further tree loss and which has led to numerous ecological problems in the city, assessing how the effect of the reduction of Karachi's green infrastructure has impacted both the reality and the perception of human health conditions. It uses medium-resolution satellite images classified for land use and land cover (LULC) data extraction and detailed field surveys to map the extent of change; structured questionnaires are used to identify the perception of selected, targeted groups regarding the state of Karachi's urban green infrastructure and perceived human health conditions. Findings indicate that the public perception of green space functionality or presence does not equate with the remote sensing and field mapping results, which show a dramatic loss. The need to develop a comprehensive urban greening strategy, which considers the needs and priorities of the population, is identified. The impact of such a strategy in terms of increased frequency of visits to green sites and associated increase in the physical activity of the people to improve overall physical health is discussed in relation to the general development of Karachi.