Screening of in Vitro Antioxidant Activity of Seaweed, Hypnea musciformis

Seaweeds are considered as a rich source of bioactive compounds as they are able to produce a great variety of secondary metabolites characterised by a broad spectrum of biological activities including antioxidant property. However, in contrast to terrestrial plants, only a few studies have reported the antioxidant activity of seaweeds. In the present study antioxidant activities of three different solvent extracts (hexane, methanol and aqueous) of Hypnea musciformis were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and phosphor molybdenum reduction assay. Total Phenolic Content (TPC) was evaluated using Folin-Ciocalteu method and the total flavonoid content was determined by the aluminium chloride (AlCl3) colourimetric method. Characterisation of the crude extracts were carried out using FT-IR analysis. The highest total antioxidant activity was recorded in methanol extract (14.50±0.58 AAE/g) whereas the lowest antioxidant activity was recorded in aqueous extract (0.75±0.29). The total antioxidant activity of hexane extract was recorded as 3.20±0.231 AAE/g. Butylated hydroxytoluene (BHT) was used as positive control and total antioxidant activity was recorded as 19.50±0.58 AAE/g. The highest DPPH antioxidant activity was obtained for methanol extract (IC50=28.00±2.31 mg/L) while the lowest activity was obtained for the aqueous extract (IC50=6006.00±6.93 mg/L). Gallic acid was used as the standard and BHT was used as the positive control and IC50 values were recorded as 3.50±0.38 mg/L and 24.00±1.15 mg/L respectively. The highest TPC was exhibited in methanol extract (14.02±0.03 GAE/g) whereas the lowest was recorded in aqueous extract 0.89±0.07 GAE/g. TPC of BHT was recorded as 254.93±4.43 GAE/g. The highest TFC was recorded in methanol extract (0.0170±0.04 QE/g) and the lowest TFC was recorded in aqueous extract (0.0098±0.14 QE/g). The TFC content of the hexane extract was 0.0102±0.13 QE/g. FT-IR analysis revealed the presence of alcohols/phenols, alkanes, carboxylic acids, alkenes, aromatics and aromatic amines, aliphatic amines in methanol crude extract. The study emphasises the importance of isolating and examining individual bioactive compounds present in H. musciformis for future research as it has revealed the antioxidant activities.Keywords: Hypnea musciformis, Antioxidant activity, DPP

Effect of Total Phosphorous, pH and Electric Conductivity on the Seasonal Occurrence of Geosmin in Some Water Bodies Sri Lanka

Cyanobacteria and actinomycetes are well known for their capability to produce taste and odour (T and O) causing compounds in water as their secondary metabolites. Geosmin (trans-1, 10-dimethyl-trans-9-decalol)) is one of the major T and O causing compounds producing earthy T and O and has become a major issue in worldwide water sector. Despite of not detecting as a human health hazard, presence of this odorant directly causes drinking water aesthetically unacceptable and leads to consumer rejection of treated drinking water due to conventional treatment processes do not remove Geosmin. Geosmin is prevailing in some Sri Lankan raw water bodies where water is taken for treatment purposes by National Water Supply and Drainage Board. The objective of the present study was to find the seasonal variation of Geosmin in Sri Lankan water bodies with respect to some physico-chemical aspects aiming to manage the T and O issue in Sri Lanka. Sampling was carried out from June 2016 to June 2018 covering both dry and wet seasons. Geosmin contamination level in 20 water bodies in Sri Lanka were analysed by Solid Phase Micro Extraction (SPME) coupled with Gas Chromatography Mass Spectrometry (GC/MS). The physico-chemical parameters of the water body were measured using standard spectrometric and titrimetric methods. Quantification and enumeration of phytoplankton were carried out with standard method using Acidified Lugol’s solution at final concentration of 1% following natural sedimentation. Geosmin concentration of the analysed samples varied between 7.8±3.27 to 34.6±1.32 ng/L throughout the dry season and from 0 to 18.3±1.22 ng/L during the wet season. Among the selected raw water bodies; the highest level of Geosmin was recorded in Sagama tank (34.6±1.32 ng/L) while the lowest was detected in Nallachchiya tank (7.8±3.27) during the dry season. During the wet season, the highest level of Geosmin was recorded in Sagama tank (18.3±1.22 ng/L) where not detected levels were recorded in Kondawatuwana tank, Jayanthi tank, Kanthale tank and Unnichchi tanks. Anabaena sp., Microcystis sp., Cylindrospermopsis sp., Oscillatoria sp., Cyclotella sp. Volvox sp., Gloeocystis sp., and Uroglenopsis sp. are the major taste and odour forming cyanobacteria recorded from the reservoirs during the study. Total cyanobacteria cell density varied between 102,560±2.28 cells/ml (Thuruwila tank) to 3,649±0.34 cells/ml (Ridiyagama tank) in dry season whereas from 98,235±4.73 (Beire lake) cells/ml to 135±3.11 cells/ml (Kanthale tank) during wet season. Detected Geosmin level in dry season was greater than the wet season. The Pearson’s correlation coefficient analysis revealed a significantly strong positive correlation between Geosmin level and the total phosphorus concentration (r=0.850, (p<0.05), water pH (r=0.788 (p<0.05)) and the Electrical Conductivity level (r=0.612, (p<0.05). Further, it was found that cyanobacteria cell density (r=0.691, (p<0.05)) had a significant positive correlation with Geosmin level in water bodies. These findings are crucial in understanding and managing natural reservoirs to eliminate T and O issue to provide a better quality drinking water to Sri Lankan general public.Keywords: Geosmin, SPME, GC/MS, Physico-chemical parameters, Seasonal variatio

Evaluation of the Impact of Natural Microcystin-LR Extract on Brine Shrimp as an Invertebrate Bioassay Model

Frequent occurrences of toxic cyanobacteria dominantly Microcystis aeruginosa bloom arebecoming a nuisance problem in Sri Lankan reservoirs in conformity with its globalenvironmental and health issues. Most of cyanobacteria produce heat stable cyanotoxinswhich have potent health impacts. Many researchers have focused on pure cyanobacterialtoxins and little was known about the toxic effect of natural cyanobacteria. The present studywas carried out to investigate the effect of natural cyanobacterial toxins on Artemia salina(Brine shrimp) as a bioassay. The toxin, Microcystin LR was extracted from bloom samplescollected from Beira and Borelesgamuwa Lakes. Both water bodies were dominated bycyanobacterium M. aeruginosa, which may contain toxic and non toxic strains. Density of M.aeruginosa at the sampling occasion in Beira Lake was 9.64x105cells/l and inBoralesgamuwa Lake was 5.31x105 cells/l respectively. One liter of lake water was filteredthrough GF/C glass microfiber filters (47 mm) and the filter disks with entrappedcyanobacterial cells were ultrasonicated with 20 ml of 100% methanol for 5 minutes and thenthe methanolic extract was filtered and HPLC-DAD analysis was done to quantify theMicrocystin (MC)-LR. MC-LR in Beira Lake was 17.13±0.02 μg/ml. In BorelesgamuwaLake MC-LR was not detected at the sampling occasion. Methanol in the extract wasevaporated and subsequently a known weight of residue was re-suspended in 2 ml of filteredsea water to make stock solutions of crude extracts to use for the bioassay. Artemia eggs werepurchased and allowed to hatch with continuous aeration in filtered sea water undercontinuous white fluorescent light for 18 h. After incubation newly hatched naupli of Artemiawere collected. For the bioassay about 30 Artemia naupli were inoculated into each well in96-well microplate. To confirm the initial number of naupli in each well, counting wasperformed under the microscope. MC-LR standard and extracts from Beira andBoralesgamuwa Lakes were used to prepare toxin (MC-LR) at final concentration series of0.1, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0 and 50.0 μg/ml. Number of dead individuals were counted ineach well after 6, 12, 18, 24 and 48 hours incubation. EC50 (50% effective concentration)values were assessed using non-linear regression by Graph Pad Prism software. EC50 value ofMC-LR standard was 4.78 μg/ml after 6 h incubation. However, EC50 values ofcyanobacterial crude extracts from Beira and Boralesgamuwa lakes at the same incubationperiod was 4.98 and 9.83 μg dry weight/ml respectively. The results showed that the standardMC-LR and cyanobacterial crude extracts from Beira Lake had almost similar EC50 valuewhile Boralesgamuwa Lakes was significantly deviated and having higher (p<0.05) EC50value. The higher toxicity of Beira Lake crude extract was due to presence of MC-LR in theextract. As confirmed by the HPLC, MC-LR was not detected in the extract prepared fromBoralesgamuwa Lake. Though the extracts showed toxicity effect on Artemia reveal that thetoxicity may due to other cyanotoxin variants present in the extracts. Further, it was detectedthat decreasing tendency of EC50 values along with the increasing incubation periods for allextracts and standard

Storing self-contained gel capillary cassettes for POC medical diagnostics

For effective clinical uptake of the lab on a chip/point of care technology (LOC-POC), in addition to cost advantages LOC-POC devices should offer multiple patient screening panels for related diseases as well as cold-chain transportation and storage abilities. We recently described a device that performs polymerase chain reaction (PCR) to simultaneously screen raw clinical samples from up to 16 patients for multiple infectious agents (Manage et al., Lab Chip, 2013, 13, 2576–2584). This cassette contains glass capillaries with desiccated semi-solid acrylamide gels that include all the reagents except for the sample, with integrated quality control. Here we report the development of protocols to store assembled PCR cassettes at room temperature, 4 uC or 220 uC as well as at +40 uC. We show that our cassettes are stable, with no loss of activity for at least 3 months at RT and at least 7 months at 4 uC and 220 uC. However, the activity of desiccated cassettes degrades when stored for more than 2 weeks at 40 uC, insufficient time for postmanufacture delivery and use of cassette PCR. To address this, we have evaluated two stage storage protocols. PCR cassettes can initially be stored at 4 uC and 220 uC for prolonged periods of time and removed for shorter term storage at RT, retaining activity for at least a month, which would facilitate transport to remote areas for testing. Effective use of cassette PCR in high temperature regions of the world, for experimental purposes defined here as 40 uC, appears to be feasible only after a first stage storage in the cold, followed by no more than 1 week at 40 uC. This should allow sufficient time for delivery by the manufacturer to a central area well served by power and refrigeration, for later ambient temperature transport and use in under-resourced areas that lack refrigeration

Evaluation of Groundwater Quality in Five Grama Divisions of Maharagama Urban Area Using Groundwater Quality Index (WQI)

Maharagama urban area is a heavily populated area in Colombo district. Groundwater in this area is having a great vulnerability for pollution by anthropogenic activities. The present study was carried out to monitor some important water quality parameters, to evaluate the quality of groundwater in the study area using a Water Quality Index (WQI) and to compare the water quality between Grama Niladari (GN) divisions in the study area. Five GN divisions (Jambugasmulla, Gangodawila south B, Wijerama, Navinna and Wattegedara) were selected for the study. 55 wells were sampled during the study. The resulted WQI values in groundwater ranged from 17.08 to 280.91. The results revealed that the water quality of the wells deviate from excellent to very poor quality. The nitrate concentration was high (>45mg/l) in some wells. Considering all the water quality parameters, the poorest water quality was recorded in Navinna GN division. It was observed that unregulated garbage dumping, uncontrolled application of organic and inorganic fertilizers, constructing toilet pits very close to wells and unregulated human settlements have been increasing in the study area. KEYWORDS: Ground water, nitrate, water quality, water quality inde

Invasive Aquatic Plants as Potential Sustainable Feedstocks for Biochar Production and as an Innovative Approach for Wastewater Treatment

Biochar (BC) is a well-established physical treatment method. The high-cost BC limits their use as adsorbents in wastewater. Thus, deriving BC from cheap and locally available waste materials is needed to develop a feasible waste removal technology. Nowadays, BC technology makes it possible to envision a new strategy to manage invasive plants by converting them into value-added products like BC. Hence, the present study was designed to evaluate the potential utilization of BC as an efficient filter medium made by invasive aquatic plants, Salvinia spp., and Eichhornia spp. A mass of 50 g of prepared activated and nonactivated BC was incorporated in a sand and gravel filter to treat rubber-manufactured wastewater. Wastewater was passed through the filter, and both raw and treated water samples were analyzed for pH, Total Suspended Solids (TSS), Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), Ammoniacal-Nitrogen (NH3-N), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Phosphates (TP), Nitrate (NO3-N), turbidity and heavy metals (Zinc, Chromium). The control filter was developed only with sand and gravel, excluding BC. Fourier Transform-Infrared Spectroscopy (FT-IR) and Scanning electron microscopy (SEM) were used to analyze BC’s chemical and physical characteristics. A brine shrimp lethality assay was carried out for toxicological evaluation. OH stretching (3,550-3,200 cm−1), C=C aromatic stretching (1400-1660 cm−1), and Phenol-O-H bending (1,300-1,400 cm−1) were recorded in all BC samples that involved the adsorption mechanism. Observed images indicated differences in surface morphology of both activated and nonactivated BC were observed under SEM observation. The study concludes that the filter unit incorporated with activated Eichhornia spp. Gave the best treatment efficiency when compared to filter units incorporated with other activated and nonactivated BC. The toxicity assay revealed 100% mortality in the control setup and raw wastewater but only 60–70% in the nonactivated BC integrated filters. Activated BC-incorporated filters showed no mortalities. Hence, the study’s outcomes suggest a green approach using invasive aquatic plants for sustainable wastewater treatment

Formulation of Novel Microbial Consortia for Rapid Composting of Biodegradable Municipal Solid Waste: An Approach in the Circular Economy

Urbanization and rapid industrialization have led to the escalation of municipal solid waste generation and accumulation. Composting is widely recognized as a sustainable solution for solid waste management. However, its long-term investment is considered a disadvantage. The present research study discusses the rapid biotransformation of solid waste into valorized compost. Bacteria were isolated from soil, solid waste, and leachate samples from open dump sites. From the 18 different bacterial consortia created using potential isolates, the five most promising consortia were selected based on concurrent different enzyme production. These selected consortia were incorporated into typical compost bins with Municipal Solid Waste (MSW). Daily monitoring of enzymatic activity, pH, conductivity, bulk density, moisture, and temperature, along with other composting parameters, was conducted. The study’s results demonstrated that consortium No. 5, comprising Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, exhibited significant (p<0.05) enzyme activity of cellulase, amylase, lipase and proteinase enzymes during composting compared to the control and other treatment setups. Consortium No. 5 also facilitated rapid and successful composting, as evidenced by significant alterations of composting parameters by exhibiting a shorter average composting time, reducing it from 110±10 days to 20±3 days, showcasing the potential applicability of formulated bacterial consortium as a sustainable and greener approach to the global solid waste problem. The novelty of this study lies in the isolation of local bacterial strains from open dump sites soil, MSW, and MSW leachate samples, which were then utilized in the composting organic fraction of MSW, enhancing the potential for effective waste management

An enclosed in-gel PCR amplification cassette with multi-target, multi-sample detection for platform molecular diagnostics

This work describes a self-contained, simple, disposable, and inexpensive gel capillary cassette for DNA amplification in near point of care settings. The cassette avoids the need for pumps or valves during raw sample delivery or polymerase chain reaction (PCR) amplification steps. The cassette contains capillary reaction units that can be stored at room temperature for up to 3 months. The current cassette configuration format can simultaneously tests up to 16 patients for two or more targets, accommodates different sample types on the same cassette, has integrated positive and negative controls and allows flexibility for multiple geometries. PCR reagents in the cassette are desiccated to allow storage at room temperature with rehydration by raw sample at the time of testing. The sample is introduced to the cassette via a transfer pipette simply by capillary force. DNA amplification was carried out in a portable prototype instrument for PCR thermal cycling with fluorescence detection of amplified products by melt curve analysis. To demonstrate performance, raw genital swabs and urine were introduced to the same cassette to simultaneously detect four sexually transmitted infections. Herpes Simplex Viruses (HSV-1 and HSV-2) were detected from raw genital swabs. Ureaplasma Urealyticum (UU) and Mycoplasma Homonis (MH) were detected from raw urine. Results for multiple patients were obtained in as little as 50'. This platform allows multiparameter clinical testing with a pre-assembled cassette that requires only the introduction of raw sample. Modification of the prototype device to accommodate larger cassettes will ultimately provide high throughput simultaneous testing of even larger numbers of samples for many different targets, as is required for most clinical applications. Combinations of wax and/or polymer cassettes holding capillary reaction units are feasible. The components of the cassette are suited to mass production and robotic assembly to produce a readily manufactured disposable reaction cassette that can be configured for disease-specific testing panels. Rapid testing with a disposable reaction cassette on an inexpensive instrument will permit on the spot evaluation of patients in the clinic for faster medical decision-making and more informed therapeutic choices

Population Dynamics and Diversity of Viruses, Bacteria and Phytoplankton in a Shallow Eutrophic Lake

We have studied the temporal variation in viral abundances and community assemblage in the eutrophic Lake Loosdrecht through epifluorescence microscopy and pulsed field gel electrophoresis (PFGE). The virioplankton community was a dynamic component of the aquatic community, with abundances ranging between 5.5 × 107 and 1.3 × 108 virus-like particles ml−1 and viral genome sizes ranging between 30 and 200 kb. Both viral abundances and community composition followed a distinct seasonal cycle, with high viral abundances observed during spring and summer. Due to the selective and parasitic nature of viral infection, it was expected that viral and host community dynamics would covary both in abundances and community composition. The temporal dynamics of the bacterial and cyanobacterial communities, as potential viral hosts, were studied in addition to a range of environmental parameters to relate these to viral community dynamics. Cyanobacterial and bacterial communities were studied applying epifluorescence microscopy, flow cytometry, and denaturing gradient gel electrophoresis (DGGE). Both bacterial and cyanobacterial communities followed a clear seasonal cycle. Contrary to expectations, viral abundances were neither correlated to abundances of the most dominant plankton groups in Lake Loosdrecht, the bacteria and the filamentous cyanobacteria, nor could we detect a correlation between the assemblage of viral and bacterial or cyanobacterial communities during the overall period. Only during short periods of strong fluctuations in microbial communities could we detect viral community assemblages to covary with cyanobacterial and bacterial communities. Methods with a higher specificity and resolution are probably needed to detect the more subtle virus–host interactions. Viral abundances did however relate to cyanobacterial community assemblage and showed a significant positive correlation to Chl-a as well as prochlorophytes, suggesting that a significant proportion of the viruses in Lake Loosdrecht may be phytoplankton and more specific cyanobacterial viruses. Temporal changes in bacterial abundances were significantly related to viral community assemblage, and vice versa, suggesting an interaction between viral and bacterial communities in Lake Loosdrecht