Freshwater Samples Research Articles

Novel bacteriophage-mediated β-lactamase-encoding genes and their risk assessment in environmental communities

Bacteria can obtain antibiotic resistance genes (ARGs) through multiple transmission routes, including horizontal gene transfer mediated by phages. Sequence-based metagenomics can detect novel phage-derived ARGs and avoid spending a great deal of time on phage isolation. Here, a metagenomic method was applied to explore the presence of ARGs in phages in freshwater samples. Two novel β-lactamase-encoding genes, blaORF88 and blaORF47, were identified and characterized in phage genomes for the first time in this study. Phylogenetic analyses indicated that blaORF88 is a member of the class C β-lactamase family, while blaORF47 formed an independent branch away from the class C β-lactamases. The average absolute abundance of blaORF88 in phage DNA and bacterial DNA was as high as 5.14 log GC/100 ml and 5.73 log GC/ml, respectively. The blaORF47 gene detected in bacterial DNA was found at the highest concentration, particularly in urban sewage samples, with 5.32 log GC/ml. Our findings raise concerns that phages might carry unknown or novel ARGs, which may spread into bacteria, leading to the emergence of antibiotic-resistant bacteria in the environment, and we urgently need effective strategies to avoid the health risks caused by ARGs.

Contributions from the main river of the largest open sea delta in the Americas to the CO2 fluxes

In this study, we sampled for the first time the main channel of the Parnaíba Delta, the largest open sea delta in the Americas, and two of its secondary channels, during the rainy season. Continuous measurements of pCO 2, temperature, salinity, and wind velocity were taken, while subsurface water samples were collected to analyze for dissolved oxygen, pH, total alkalinity, dissolved organic carbon, and its isotopic, chlorophyll-a, and nutrients. The spatial variability of pCO 2 along the different channels showed the existence of distinct drivers of CO2 dynamics in the area. The correlation of pCO 2 in freshwater samples with dissolved oxygen and chlorophyll-a indicated the incidence of organic matter decomposition and primary production in the main channel and mangroves, while the highest salinity samples evidenced the control of carbonate equilibrium in the river mouth. Our data also indicated an important influence of the river discharge on the carbon dynamics of the estuary, with around 73% of the CO2 emissions in the estuary estimated to be from riverine CO2. The strong river effect in the estuary was also supported by the low salinities (0.04–26.37), pH (7.09 ± 0.36), and total alkalinity (328 ± 530.46 μmol kg −1), typical from fluvial waters. The estuary was supersaturated in CO2 and behaved as a strong source, with an average flux of 194.1 ± 135.1 mmol m−2 d−1.

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

The development and spread of antibiotic resistance (AR) through microbiota associated with freshwater bodies is a major global health concern. In the present study, freshwater samples were collected and analyzed with respect to the total bacterial diversity and AR genes (ARGs) using both conventional culture-based techniques and a high-throughput culture-independent metagenomic approach. This paper presents a systematic protocol for the enumeration of the total and antibiotic-resistant culturable bacteria from freshwater samples and the determination of phenotypic and genotypic resistance in the culturable isolates. Further, we report the use of whole metagenomic analysis of the total metagenomic DNA extracted from the freshwater sample for the identification of the overall bacterial diversity, including non-culturable bacteria, and the identification of the total pool of different ARGs (resistome) in the water body. Following these detailed protocols, we observed a high antibiotic-resistant bacteria load in the range of 9.6 × 105-1.2 × 109 CFU/mL. Most isolates were resistant to the multiple tested antibiotics, including cefotaxime, ampicillin, levofloxacin, chloramphenicol, ceftriaxone, gentamicin, neomycin, trimethoprim, and ciprofloxacin, with multiple antibiotic resistance (MAR) indexes of ≥0.2, indicating high levels of resistance in the isolates. The 16S rRNA sequencing identified potential human pathogens, such as Klebsiella pneumoniae,and opportunistic bacteria, such as Comamonas spp., Micrococcus spp., Arthrobacter spp., and Aeromonas spp. The molecular characterization of the isolates showed the presence of various ARGs, such as blaTEM, blaCTX-M (β-lactams), aadA, aac (6')-Ib (aminoglycosides), and dfr1 (trimethoprims), which was also confirmed by the whole metagenomic DNA analysis. A high prevalence of other ARGs encoding for antibiotic efflux pumps-mtrA, macB, mdtA, acrD, β-lactamases-SMB-1, VIM-20, ccrA, ampC, blaZ, thechloramphenicol acetyltransferase gene catB10, andthe rifampicin resistance gene rphB-was also detected in the metagenomic DNA. With the help of the protocols discussed in this study, we confirmed the presence of waterborne MAR bacteria with diverse AR phenotypic and genotypic traits. Thus, whole metagenomic DNA analysis can be used as a complementary technique to conventional culture-based techniques to determine the overall AR status of a water body.

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

The development and spread of antibiotic resistance (AR) through microbiota associated with freshwater bodies is a major global health concern. In the present study, freshwater samples were collected and analyzed with respect to the total bacterial diversity and AR genes (ARGs) using both conventional culture-based techniques and a high-throughput culture-independent metagenomic approach. This paper presents a systematic protocol for the enumeration of the total and antibiotic-resistant culturable bacteria from freshwater samples and the determination of phenotypic and genotypic resistance in the culturable isolates. Further, we report the use of whole metagenomic analysis of the total metagenomic DNA extracted from the freshwater sample for the identification of the overall bacterial diversity, including non-culturable bacteria, and the identification of the total pool of different ARGs (resistome) in the water body. Following these detailed protocols, we observed a high antibiotic-resistant bacteria load in the range of 9.6 × 105-1.2 × 109 CFU/mL. Most isolates were resistant to the multiple tested antibiotics, including cefotaxime, ampicillin, levofloxacin, chloramphenicol, ceftriaxone, gentamicin, neomycin, trimethoprim, and ciprofloxacin, with multiple antibiotic resistance (MAR) indexes of ≥0.2, indicating high levels of resistance in the isolates. The 16S rRNA sequencing identified potential human pathogens, such as Klebsiella pneumoniae, and opportunistic bacteria, such as Comamonas spp., Micrococcus spp., Arthrobacter spp., and Aeromonas spp. The molecular characterization of the isolates showed the presence of various ARGs, such as blaTEM, blaCTX-M (β-lactams), aadA, aac (6')-Ib (aminoglycosides), and dfr1 (trimethoprims), which was also confirmed by the whole metagenomic DNA analysis. A high prevalence of other ARGs encoding for antibiotic efflux pumps-mtrA, macB, mdtA, acrD, β-lactamases-SMB-1, VIM-20, ccrA, ampC, blaZ, the chloramphenicol acetyltransferase gene catB10, and the rifampicin resistance gene rphB-was also detected in the metagenomic DNA. With the help of the protocols discussed in this study, we confirmed the presence of waterborne MAR bacteria with diverse AR phenotypic and genotypic traits. Thus, whole metagenomic DNA analysis can be used as a complementary technique to conventional culture-based techniques to determine the overall AR status of a water body.

Varying growth behavior of redox-sensitive nanoparticles on 1:1 and 2:1 clay surfaces: Mechanistic insights on preferential toxic ions removal in mono, co, and multi-metal contaminated waters

In the current study, contrasting growth behaviour of redox sensitive Fe0 nanoparticles (nZVI) was observed on different clay surfaces i.e., 1:1 non-swelling kaolinite (K-nZVI) and 2:1 swelling bentonite (B-nZVI). Osmotic swelling of bentonite led to Fe0 nucleation and growth of 5–7 nm size particles in the broadened interlayer spaces. B-nZVI had negative zeta potential due to the domination of the surface charge of bentonite clay. In contrast, kaolinite has shown dominant surface growth of nZVI particles (>24.8 ± 7.4 nm) and positive zeta potential, suggesting domination of Fe0 nanoparticles (nZVI) characteristics. This surface-dependent variation led to higher and faster removal of oxy-anions with K-nZVI, i.e., chromium and arsenic (87.5 and 157.35 mg/g) than B-nZVI (18.4 and 86.9 mg/g). In comparison, B-nZVI has shown higher sorption of cations i.e., nickel and cadmium (36 mg/g and 46 mg/g) than K-nZVI (25 and 27 mg/g). XPS and pXRD analysis of reaction precipitates confirmed reductive sorption of chromium, co-precipitation/ complexation of arsenic, electrostatic attraction and complexation of nickel and cadmium as major removal mechanisms. Drastically higher total contaminant sorption capacities of B-nZVI (327 mg/g) and K-nZVI (372 mg/g) in multi-contaminant (Cr + As + Ni + Cd) solutions than individual capacities in mono-ionic solutions was due to co-operative effects and newer sites induced via sorption and redox-transformation of other ionic species. K-nZVI removed chromium and arsenic to below drinking water permissible limits whereas B-nZVI succeeded in separating nickel and cadmium to drinkable levels in groundwater, freshwater, river water, and wastewater samples, emphasizing their applicability in high cationic—low anionic and low cationic-higher anionic species contaminated waters, respectively.

Assessment of Physicochemical and Microbiological Qualities of Potable Water Sources in Okorenkoko, Delta State Nigeria

Accessibility of Potable water in rural and riverine communities have reduced drastically in recent times. A total of six borehole water samples and a freshwater sample were obtained from Okerenkoko community in Delta State, Nigeria. The water samples were analyzed for physicochemical and microbiological parameters using standard procedures. Pearson correlational analysis was employed to evaluate the level of association of the data using Statistical Package for Social Sciences version 23. Our results showed that pH concentration values ranged from 5.62 to 7.81, electrical conductivity had 10.03 to 490.01 µS/cm, dissolved oxygen varied from 3.90 to 7.91 mg/L, COD had 10.01 to 50.03 mg/L. The fecal coliform count ranged from 4- 2400 MPN/ml, while the surface water had a fecal coliform count 2400 MPN/ml; fungal count 3.1 Log10CFU/ml and 3.6 Log10CFU/ml respectively, Total aerobic count had a maximal concentration value of 5.8 Log10CFU/ml and 5.4 Log10CFU/ml; Total Salmonella Shigella Count it had a concentration of 4.0 Log10CFU/ml. Microbes associated with the water samples were Bacillus sp., Escherichia sp., Staphylococcus sp., Streptococcus sp., Shigella sp., Proteus sp., Pseudomonas sp., Klebsiella sp., Vibrio sp. and Micrococcus sp. There is an urgent need to source-track the trajectory of pollutants from both from domestic and industrial activities. There is need that the government at all levels should improve the available potable water resources in Okerenkoko community.

Improvement of recovery yield of macro-organismal environmental DNA from seawater samples

In recent years, environmental DNA (eDNA) technology has been used in a variety of water environments. Environmental DNA concentrations in marine samples tend to be lower than those in freshwater samples, and few studies have explored methods to improve the recovery yields of eDNA from seawater samples. In this study, we compared different seawater preservation solutions (RNAlater or ATL) to improve eDNA yields. The eDNA concentrations of vertebrate and invertebrate species were compared using species-specific eDNA assays, and the number of detected fish and their compositions were compared using metabarcoding analysis. ATL treatment resulted in significantly higher eDNA yields for both vertebrate and invertebrate species than RNAlater treatment. Metabarcoding analysis revealed non-significant effects of preservation on the number of detected species and species composition. These results suggest that ATL treatment improves DNA yields without changing the species composition compared with the commonly used RNAlater treatment. The findings of this study will reduce false-negative outcomes and provide highly reliable results in future biological surveys.Graphical abstract

A new species of Amphorotia (Bacillariophyta) from a freshwater section of the Pearl River with comments on associated species and biogeography of the genus

Based on a review of material previously studied, and new water samples, species of the genus <i>Amphorotia</i> were investigated with respect to their morphology and geographical distribution, especially in subtropical Asian coastal areas. Six <i>Amphorotia</i> species from China are investigated. They all possess amphoroid frustule symmetry, presence of spines and, when detected, a single plastid. These features as well as other details of the frustules were documented with light and scanning electron microscopy. Five of the taxa, <i>A. reimerii</i>,<i> A. mokonensis</i>,<i> A. baicalensis</i>,<i> A. zhujiangensis</i>, and <i>A. curvata</i> are newly recorded as fossil specimens in the Jianghan Plain. Further comments on the taxonomy and morphological variation of several known species are given. One taxon, <i>A. liangyanlingii</i> sp. nov. was discovered from freshwater samples in the Pearl River. This new species is most similar to<i> A. zhujiangensis</i> Wu, Williams et Flower when observed in LM, but can be distinguished by ultrastructural details when viewed with the scanning electron microscope (SEM). Taxonomical studies of species in the genus <i>Amphorotia</i> are considered together with their biogeography and ecology.

Ionic Liquid-Dispersive Micro-Extraction and Detection by High Performance Liquid Chromatography-Mass Spectrometry for Antifouling Biocides in Water.

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid-liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7-90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01-0.1 μg L-1. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater.

Three Phages from a Boreal Lake during Ice Cover Infecting Xylophilus, Caulobacter, and Polaromonas Species.

Although the important role of microbes in freshwater is well understood, studies on phage-host systems in such environments during ice cover are completely lacking. Here, we describe the isolation and characterization of three new bacteriophages infecting Xylophilus sp., Caudobacter sp., and Polaromonas sp. from freshwater samples taken under the ice cover of Lake Konnevesi, Finland. Lumi, Kuura, and Tiera bacteriophages have tailed icosahedral virions and double-stranded DNA. Lumi is a siphophage with a genome of 80,496 bp, and Kuura and Tiera are podophages, and their genomes are 43,205 and 45,327 bp in length, resembling viruses in the class Caudoviricetes. Their host ranges were very limited among the winter-isolated bacterial strains from Konnevesi, each infecting only their own hosts. They can infect efficiently at 4 °C, showing that they are adapted to living in lake water under ice cover. Analysis of the viral genome sequences showed that a significant number of the gene products of each virus are unique, indicating that there is unexplored viral diversity in freshwaters. To our knowledge, Lumi and Tiera are the first phages isolated on the Xylophilus sp. and Polaromonas sp. strains, allowing their exploitation in further studies of freshwater bacterial-phage interactions.

Assessment of toxic normal saturated hydrocarbons in the Arabian seawater and Omani freshwater samples using liquid chromatography–mass spectrometry

The NHs contaminated water samples can cause several health problems such as skin irritation, acne, irregular breathing, lung irritation, cardiac arrest, itching, central nervous system (CNS), and cancer. Therefore, this current study aims to develop extraction and detection methods for normal hydrocarbons (NHs) in water samples with dichloromethane (DCM) and to detect and quantify the level of NHs in the seawater and freshwater samples by using liquid chromatography-mass spectrometry (LC–MS). Sixty-four water samples were collected from five different ports of Oman, including, Matrah, Al Mouj Marina, Salalah, Duqm, and Sohar ports, and one fresh water from Falaj Daris. The solvent–solvent extraction method was used to extract the NHs of seawater and freshwater sample with DCM. The DCM layer was passed through the silica gel column and evaporated DCM by using a rotary evaporator at low temperature and pressure. The samples were analyzed using liquid chromatography-mass spectrometry (LC/MS). The results showed that all collected seawater and freshwater samples contain NHs, but the concentration is below the detection limit. The water samples of those selected areas were not polluted by NHs toxicants. In conclusion, the low concentration of NHs could be due to the effective treatment of effluents discharged by industries, refineries, ships, and other marine vehicles. So far, it is the first report on extracting and detecting NHs in seawater and freshwater samples using LC/MS.

Transcriptome Analysis Revealed Osmoregulation Related Regulatory Networks and Hub Genes in the Gills of Hilsa shad, Tenualosa ilisha, during the Migratory Osmotic Stress

Tenualosa ilisha (Hilsa shad), an anadromous fish, usually inhabits coastal and estuarine waters, and migrates to freshwater for spawning. In this study, large-scale gill transcriptome analyses from three salinity regions, i.e., fresh, brackish and marine water, revealed 3277 differentially expressed genes (DEGs), out of which 232 were found to be common between marine vs freshwater and brackish vs freshwater. These genes weremapped into 54 KEGG Pathways, and the most significant of thesewere focal adhesion, adherens junction, tight junction, and PI3K-Akt signaling pathways. A total of 24 osmoregulatory genes were found to be differentially expressed in different habitats. The gene members of slc16 and slc2 families showed a dissimilar pattern of expressions, while two claudin genes (cldn11 & cldn10), transmembrane tm56b, and voltage-gated potassium channel gene kcna10 were downregulated in freshwater samples, as compared to that of brackish and marine environment. Protein-protein interaction (PPI) network analysis of 232 DEGs showed 101 genes to beinvolved in PPI, while fn1 gene was found to be interacting with the highest number of genes (36). Twenty-five hub genes belonged to 12 functional groups, with muscle structure development with seven genes, forming the major group. These results provided valuable information about the genes, potentially involved in the molecular mechanisms regulating water homeostasis in gills, during migration for spawning and low-salinity adaptation in Hilsa shad. These genes may form the basis for the bio-marker developmentfor adaptation to the stress levied by major environmental changes, due to hatchery/culture conditions.

Quantification of polycyclic aromatic hydrocarbon derivatives in the Arabian coastal seawater and freshwater samples

Quantification of polycyclic aromatic hydrocarbon derivatives in the Arabian coastal seawater and freshwater samples

Production of Single Cell Oils from Bacterial Sources

Single Cell Oils (SCO) is of profound interest for a variety of purposes ranging from biofuels to nutritional adjuvants, pharmaceutical applications and biotransformation for valuable products. A number of microorganisms have been shown to produce and accumulate SCO. In the present study a methodical attempt was made to isolate potential SCO producers from Indian water sources. Saltwater samples from the Arabian Sea and freshwater samples from an Indian cold-water river (Pindhari River, Uttarakhand) were collected and studied for the occurrence of lipid producing microbes. Of the several isolates shortlisted as lipid producers three isolates from this study were identified as potential SCO producers based on their lipid producing abilities. The types of fatty acids comprising the SCO from selected isolates were studied by Gas Chromatography (GC) and confirmed by Gas Chromatography/Mass Spectrometry (GC/MS). Lipid profiles from the GC analysis showed that the isolates in this study produced economically and nutritionally valuable Monounsaturated fatty acids (MUFA) like Palmitoleic acid and Oleic acid. Also, two isolates from the Arabian Sea were seen to produce a valuable omega-3 Polyunsaturated Fatty Acid (PUFA) like Eicosapentanoic acid. While a freshwater isolate produced Linoleic acid an omega-6 PUFA. Selected isolates were characterized for their biochemical characteristics and identified molecularly by 16S rRNA sequencing. Ornithinibacillus sp. Marseille-P3601 strain isolated in our study from the cold-water River Pindhari, Uttarakhand is found capable of producing PUFA.

Construction of a rapid electrochemical biosensor consisting of a nanozyme/aptamer conjugate for waterborne microcystin detection.

Microcystin-LR (MC-LR) is a hepatotoxin generated by the excessive proliferation of cyanobacteria, which is a threat to humans and wildlife. Therefore, rapid detection of MC-LR is an important challenge. This study describes a rapid electrochemical biosensor comprising nanozymes and aptamers. Alternating current electrothermal flow (ACEF) significantly reduced the MC-LR detection period to 10 min. We also used MnO2/MC-LR aptamer conjugates to improve the sensitivity to MC-LR detection. Here, MnO2 amplified the electrochemical signal and the aptamer showed high selectivity for MC-LR. Under the optimal conditions, the limit of detection (LOD) and selectivity in freshwater were detected using cyclic voltammetry and differential pulse voltammetry. As a result, an LOD of 3.36 pg mL-1 was observed in the linear concentration range of 10 pg mL-1 to 1 μg mL-1. This study quickly and sensitively detected MC-LR in a situation where it causes serious damage worldwide. In addition, the ACEF technology introduction is the first example of MC-LR detection, suggesting a wide range of possibilities for MC-LR biosensors.

Electron-transfer MALDI MS methodology for microalgae/phytoplankton pigments analysis

The method describes pigment analysis from microalgae/phytoplankton extracts using electron-transfer Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (ET MALDI MS). Current microalgae/phytoplankton pigment analysis requires resource- and time-intensive chromatographic methods due to the broad polarity range of the target analytes. On the other hand, traditional MALDI MS chlorophyll analysis, using proton-transfer matrices such as 2,5-dihydroxybenzoic acid (DHB) or α-cyano-4-hydroxycinnamic acid (CHCA), results in central metal loss and phytol–ester cleavage. ET MALDI MS is an alternative for the rapid screening and detection of pigments in microalgae extracts.•MALDI matrices with ionization energies above 8.0 eV guarantee electron-transfer processes from photosynthetic and photoprotective pigments whose ionization energies lay below 7.5 eV.•ET MALDI MS pigment analysis agrees with data gathered from conventional chromatographic techniques (HPLC) and optical microscopy for pigment extracts from C. vulgaris cultures and freshwater phytoplankton samples.•The ET MALDI MS method allows fast and reliable detection of pigments in microalgae cultures and freshwater phytoplankton samples.

Surfactant-induced disaggregation of a quinoxaline AIEgen scaffold: aggregation aptitude in the solid and solution states.

We have designed five propellor-shaped molecules based on the quinoxaline scaffold with a functional group variation. They exhibit aggregation-induced emission, and the responses of these congeners regarding good solvents and poor solvents are investigated both spectroscopically and microscopically. Solid- as well as solution-state parallel analysis of the aggregation facet is laid out. Notably, L2 interacts specifically with a cationic surfactant, unlike other congeners where the mechanism proceeds via disaggregation. Real sample analysis was carried out on freshwater samples as well as waste effluent samples from domestic households and industries, thus projecting the analytical and environmental significance.

Pesticide Determination in Fresh Coconut Water (Cocos nucifera Linn.) by GC-MS Using Microwave-Assisted Liquid-Liquid Extraction

Fresh coconut (Cocos nucifera) water, a popular beverage in tropical countries, is often exposed to pesticide contamination due to agricultural practices. Thus, this work proposed the simultaneous determination of 36 pesticides in fresh coconut water samples using liquid-liquid extraction, drying assisted by a household microwave oven, and gas gas chromatography-mass spectrometry (GC-MS) analysis. Limits of detection varied from 5.4 (disulfoton) to 9.6 ng L-1 (parathion-methyl). Nine pesticides residues were detected (dimethoate, γ-HCH, β-HCH, 4,4’-dichlorodiphenyldichloroethylene, endosulfan II, 4,4’-dichlorodiphenyldichloroethane, 4,4’-dichlorodiphenyltrichloroethane, endrin ketone, and methoxychlor) with concentrations from &lt; limit of quantification to 5,768.34 ± 1.64 ng L-1. Dimethoate was quantified in all samples, indicating its recent use. The proposed methodology offers several advantages, including the use of small sample volumes and solvent extraction, which eliminates the need for costly cartridges and reduces waste production. Additionally, the obtained results can be valuable for regulatory agencies, aiding in the mitigation of environmental damage and the protection of human health.

Generation of Electricity from Abattoir Waste Using Microbial Fuel Cell

This study undertook the generation of electricity from abattoir waste with the aim of eliminating the polluting effects of this waste. To achieve the aim of the study, three abattoirs were randomly selected within Ile-Ife in Osun State, southwest Nigeria. Using interactive and investigative methods, the average number of cows and goats that were slaughtered daily, weekly and monthly was established; and the amount of waste generated was subsequently estimated. Water samples were collected from water sources for the abattoirs. Wastewater samples were also collected at different carefully selected stages of the abattoir processes. The wastewater samples were exposed to air for 6 hours to 48 hours. The water and wastewater samples were then subjected to physico-chemical analysis, using standard procedures. Using standard method and appropriate materials, salt bridge was prepared and Microbial Fuel Cells (MFC) were assembled. Subsequently, electrical set up was done, abattoir wastewater introduced into the chamber and electricity generated and evaluated. Voltage, voltage drop, power and current readings were observed and recorded for a period of six (6) days (between 131-144 hours). Surveys revealed that an average of two (2) cows was slaughtered daily in each abattoir. Results showed that the quantity of waste generated from each abattoir per day stands at 100-120 kg per day. For fresh water samples, the pH fell within WHO standard (6.98 to 7.05); while the average pH value for the wastewaters showed that it is basic. Also, for fresh water samples, TS, TSS and BOD values met WHO standard (340 to 440 mg/l), 200 to 220 mg/l and 240 to 600 mg/l) respectively, while the values were excessively high for wastewaters. Generally, the voltage generated from waste with longest exposure to air had the least values. The study concluded that electricity generation is possible from abattoir waste using microbial fuel cells.

Stigmasterol- an Acetylcholinesterase Inhibitor from Phormidium retzii with relevance to Alzheimer's disease Therapy.

This study observed in vitro screening, purification and identification of cholinesterase inhibitors from the microalgae Phormidium retzii. Mixed microalgal culture was screened from freshwater samples for Phormidium sp. Single colony was purified and authenticated as P. retzii. Acetylcholinesterase (AChE) enzyme was purified from hRBC ghost. Sequential extraction of P. retzii was performed using organic solvents. Cholinesterase enzyme activity and its inhibition by various extracts were then tested. The active fractions were then subjected to partial purification and characterization. Petroleum ether extract of P. retzii showed maximum inhibition of 68.6 % against AChE while other solvent extracts showed no inhibition. Seven fractions were obtained from the active extract using thin layer chromatography. Among which fraction no. 5 showed maximum inhibition of 86.37 % towards AChE. Fraction no. 5 when subjected to GC-MS led to determination of the active principle as stigmasterol. The maximum inhibition of stigmasterol (0.45µM) was 81.2±0.08% with IC50 value of 0.214. Stigmasterol from P. retzii inhibited AChE projecting itself as safer drug for Alzheimer's disease with minimal side effects.