Determination of the Insecticide Azamethiphos in Water and Soil using High Performance Liquid Chromatography

Azamethiphos (AZA) is an organophosphorus insecticide used to control flies and cockroaches. Most of open dump sites in Sri Lanka AZA is applied as insecticide to control fly and studies on the occurrence of the insecticide in the environment after application was not recorded. Thus, the aim of this study was to optimise an analytical method to detect AZA in the environmental samples using High Performance Liquid Chromatography (HPLC). AZA in water samples were extracted using the Solid Phase Extraction (SPE) method following the methanol elute, rotary evaporation at 44.4o C and the final residue was re-dissolved in 2.00 mL of HPLC grade Acetonitrile–water (20:80 v/v) for HPLC analysis. AZA residues in soil samples collected from dump site at Karadiyana was subjected to extract AZAinto Acetonitrile and then the solid phase extraction followingrotary evaporation andre-dissolved in 1.00 mL of acetonitrile-water (20:80, v/v) prior to analysis. Quantification of AZA was carried out using the HPLC system consisting of Agilent 1200 series. Two mobile phases were optimised for the isocratic run (Acetonitrile: water=70:30). About 25 μL sample was injected into at a flow rate of 1 mLmin-1. Concentration of AZA were determined using the peak area (at 294 nm) of following the calibration curve and the detection limit for the method was 1 ppm. Soil and water recovery of the method were 94.65±0.13 μgL-1 and 94.02±0.09 μgL-1 respectively. Levels of AZA in collected water samples from dumping site area ranged from 895.35 μgL-1 to 924.81 μgL-1 and levels of AZA in soil samples ranged around 12,000 μgL-1. Thus the optimise method is to be found more reliable and validate to detect and quantification of Azamethiphos in the environmental samples.Keywords: Azamethiphos, High performance liquid chromatography (HPLC), Solid phase extraction (SPE), Environmental sample

Human Resource Management Practices in Listed Firms in Sri Lanka

The objective of this research paper was to investigate whether size and age of listed firms relate to systematic use of HRM practices being followed by those firms and a significant difference exists between local firms and multinational firms operating in Sri Lanka with regard to systematic use of HRM practices. Three hypotheses were formulated using deductive approach. The study was conducted relating to all listed firms numbering 248, which were listed in the Colombo Stock Exchange. Type of investigation was correlational and it was cross-sectional in time horizon. The unit of analysis of this study was at firm level. The structured survey was administered to cover all the firms and human resource managers worked as the respondents on behalf of the firms. However data were possible to be collected from 66 managers representing 66 firms. In order to test the first and second hypotheses that were concerned with relationships of size and age with systematic use of HRM practices the Pearson Product-Moment Correlation technique was applied. The third hypothesis was concerned with difference between multinational firms and local firms with regard to systematic use of HRM practices and Independent Sample T test was the appropriate technique to test the validity of the hypothesis. The results of the study showed a significant difference existing between local firms and multinational firms operating in Sri Lanka with regard to systematic use of HRM practices. However the study revealed that size of the firm and the degree of systematic use of HRM practices and also age of the firm and the degree of systematic use of HRM practices are not significantly and positively related. Implication of the findings is that irrespective of the size of the firm and the age of the firm it is possible to establish good practices of Human Resource Management which contribute to provide the organization with a more appropriate and contended employee force that gives the maximum contribution to its success. In this context, top management support and employment of right personnel who specialize in HRM may be more important in enhancing the systematic use of HRM practices in firms. Key words: Age, Human Resource Management Practices, Ownership, Size, Systematic Us

EFFECT OF GRAZING ON SOME PHYSIOLOGICAL PROPERTIES IN INTEGRATED FARMING SOILS.

The objective of this study was to investigate the effect of grazing on somesoil properties; bulk density (BD), true density, porosity, moisture content(Me) and pH. The effect of long term grazing (>20 yrs) was examined in acoconut - pasture - cattle integrated farming system in Kamburupitiya area.Short term grazing effect was compared with an adjoining coconut plantationpermitting 18 buffaloes to graze for 6 months. Another adjoining ungrazedcoconut farm soil was considered as control. Soil samples were taken fromthe topsoil using a core sampler (v = 98.21 em"). Four replicate samples weretaken three times with 30 days interval and analyzed in triplicates. Data werestatistically analyzed using SAS.Soils collected from the long term integrated farming site had a significantlyhigher (p < 0.05) average pH (5.58) than that of non-integrated sites (4.65).Reduction of acidity may be due to the improvement of soil nutrients viadung, urine and accumulation of litter. It was observed that the soil inintegrated sites were comparatively dark in color. BD of integrated soil(1.15g/cm3) was significantly lower than that of non-integeated soil (21.26%)due to the better ground cover by dominant prostate type herbages comparedto ungrazed soils where erect type herbages were prominent. Soil porosityalso improved due to integration (47.76%) with that of non-integrated soil(43.76%). There was no significant difference observed under the effect ofshort term grazing. A considerable time period may be required to change toimproved soil properties.It is concluded that long term crop-livestock integration could improve thesoil physiochemical properties

THE ROLE OF ENVIRONMENTALISTS ON THE SUSTAINABLE USE OF MEDICINAL PLANTS, FROM AN AYURVEDIC PRACTITIONER'S POINT OF VIEW

The unique biological diversity of Sri Lanka is vital for the long term welfare of her ownpeople. But her natural forest cover which harbours a rich species diversity is dwindlingrapidly due to various reasons. It is customary for the traditional Ayurvcdic physicians ofSri Lanka to use plants as the major original source of drugs used in the treatment ofdiseases. However, there has been drastic decline in the availability of medicinal plants inSri Lanka since recent past. Therefore, this issue should be dealt with a multidisciplinaryapproach.A model survey was conducted in the Moneragala district in order to assess the hardshipsfaced hy the traditional physicians due to the scarcity of required varieties of plantingredients. Another survey was conducted among traditional physicians among riverandomly selected districts and also in ayurvedic pharmacies with the objective ofevaluating the status of demand of medicinal plants used for specific diseases usingdiabetes as a model. All these surveys were carried out using structured questionnaires.The outcome of these surveys strongly recommend that there is a great necessity tointegrate reforestation programmes with medicinal plant cultivation in order to cater to thedemand. Therefore. Sri Lanka needs a comprehensive strategy for the development of itsmedicinal plants. In our opinion. it is the responsibility of the environmentalists to adviseand guide the authorities concerned in preserving the medicinal plants which is ourNational heritage as well

MDM2 Integrates Cellular Respiration and Apoptotic Signaling through NDUFS1 and the Mitochondrial Network

Signaling diversity and subsequent complexity in higher eukaryotes is partially explained by one gene encoding a polypeptide with multiple biochemical functions in different cellular contexts. For example, mouse double minute 2 (MDM2) is functionally characterized as both an oncogene and a tumor suppressor, yet this dual classification confounds the cell biology and clinical literatures. Identified via complementary biochemical, organellar, and cellular approaches, we report that MDM2 negatively regulates NADH:ubiquinone oxidoreductase 75 kDa Fe-S protein 1 (NDUFS1), leading to decreased mitochondrial respiration, marked oxidative stress, and commitment to the mitochondrial pathway of apoptosis. MDM2 directly binds and sequesters NDUFS1, preventing its mitochondrial localization and ultimately causing complex I and supercomplex destabilization and inefficiency of oxidative phosphorylation. The MDM2 amino-terminal region is sufficient to bind NDUFS1, alter supercomplex assembly, and induce apoptosis. Finally, this pathway is independent of p53, and several mitochondrial phenotypes are observed in Drosophila and murine models expressing transgenic Mdm2

Proteomic DIGE analysis of the mitochondria-enriched fraction from aged rat skeletal muscle

Skeletal muscle aging is associated with a loss in tissue mass and contractile strength, as well as fiber type shifting and bioenergetic adaptation processes. Since mitochondria represent the primary site for energy generation via oxidative phosphorylation, we investigated potential changes in the expression pattern of the mitochondrial proteome using the highly sensitive DIGE approach. The comparative analysis of the mitochondria-enriched fraction from young adult versus aged muscle revealed an age-related change in abundance for 39 protein species. MS technology identified the majority of altered proteins as constituents of muscle mitochondria. An age-dependent increase was observed for NADH dehydrogenase, the mitochondrial inner membrane protein mitofilin, peroxiredoxin isoform PRX-III, ATPase synthase, succinate dehydrogenase, mitochondrial fission protein Fis1, succinate-coenzyme A ligase, acyl-coenzyme A dehydrogenase, porin isoform VDAC2, ubiquinol-cytochrome c reductase core I protein and prohibitin. Immunoblotting, enzyme testing and confocal microscopy were used to validate proteomic findings. The DIGE-identified increase in key mitochondrial elements during aging agrees with the concept that sarcopenia is associated with a shift to a slower contractile phenotype and more pronounced aerobic-oxidative metabolism. This suggests that mitochondrial markers are reliable candidates that should be included in the future establishment of a biomarker signature of skeletal muscle aging

Origin of a folded repeat protein from an intrinsically disordered ancestor.

Repetitive proteins are thought to have arisen through the amplification of subdomain-sized peptides. Many of these originated in a non-repetitive context as cofactors of RNA-based replication and catalysis, and required the RNA to assume their active conformation. In search of the origins of one of the most widespread repeat protein families, the tetratricopeptide repeat (TPR), we identified several potential homologs of its repeated helical hairpin in non-repetitive proteins, including the putatively ancient ribosomal protein S20 (RPS20), which only becomes structured in the context of the ribosome. We evaluated the ability of the RPS20 hairpin to form a TPR fold by amplification and obtained structures identical to natural TPRs for variants with 2-5 point mutations per repeat. The mutations were neutral in the parent organism, suggesting that they could have been sampled in the course of evolution. TPRs could thus have plausibly arisen by amplification from an ancestral helical hairpin