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AbstractThe present study synthesised and characterised zinc oxide nanoparticles (ZnO NPs) using spinach tree, Cnidoscolus aconitifolius and investigated its potential use as nanofertilizer. The synthesised nanoparticles showed UV–Vis absorption peak at 378 nm which is a feature of ZnO NPs. FT-IR analysis further revealed the presence of O-H stretching, C = C bending, O-H bending and C-N stretching functional groups of the stabilising action of the plant extract on the surface of the nanoparticles. SEM images displayed the shape of NPs to be spherical whereas TEM images showed their distribution sizes to be 100 nm. Synthesised ZnO NPs were used as a nano fertilizer on Sorghum bicolour plant. An increase in the shoot leaf length with an average length of 16.13 ± 0.19 cm as compared to the control group of 15.13 ± 0.07 cm was observed. The rate of photosynthesis also showed a significant increase with total chlorophyll content of 0.2806 ± 0.006 mg/mL as compared with control of 0.2476 ± 0.002 mg/mL. The activity of antioxidative enzymes was measured with an increase in the specific activity of SOD in the plant when ZnO NPs were used over NPK whereas, the specific activities of CAT were similar in all cases.

ABSTRACTThis study aims to biosynthesize zinc oxide nanoparticles using aqueous leaf extracts of Cnidoscolus aconitifolius and investigate their biological activities. UV–Vis Spectroscopy, FT-IR, SEM and TEM were used for characterization. The antioxidant properties were determined using H2O2, NO, ABTS, FRAP and DPPH scavenging assays. For anti-inflammatory activities, membrane stabilization, albumin denaturation and proteinase inhibitory activity were assayed. The antibacterial effect was tested using well diffusion method. Statistical analyses were done using ANOVA. Synthesized nanoparticles showed an intensity peak at 378 nm in UV–Vis Spectroscopy. FT-IR shows the presence of O-H stretching, C = C bending, O-H bending and C–N stretching functional groups of the stabilizing action of the plant extract on the surface of the nanoparticles. NPs were shown to be spherical by SEM analysis, and the sizes were 100 nm by TEM analysis. The antioxidant properties of ZnO NPs compared to ascorbic acid standard showed significant antioxidant potential in H2O2, NO, ABTS, FRAP and DPPH scavenging assays. ZnO NPs showed excellent anti-inflammatory activity with the synthesized ZnO NPs performing better in membrane stabilization. Clinical pathogens were inhibited by ZnO NPs when compared with Cefuroxime, a standard drug. These efficient biological activities could be utilized in several biological applications.

Strain improvement of a low fructosyltransferase-producing Aureobasidium pullulans NAC8 (Accession No. KX023301) was carried out using chemical mutagens such as ethidium bromide and ethyl methane sulfonate. The wild-type and mutant strain were distinguished using Random amplified polymorphic DNA PCR and DNA fingerprinting analysis. Plackett-Burman and Box Behnken design were statistical tools used to determine important media parameters and optimization, respectively. Phenotypically and genetically, the new improved strain was different from the wild-type. The most important media parameters from PDB influencing fructosyltransferase production were ammonium chloride, sucrose and yeast extract at p

Background. Many natural aquatic bodies have been contaminated with heavy metals released from domestic, industrial and other anthropogenic activities. Fish are an important bioindicator species and play an important role in the monitoring of water pollution. Objectives. This study shows the effect of heavy metals on the distribution of glutathione S-transferases (GST), catalase, rhodanese and 3-mercaptopyruvate sulphur transferase (3-MST) isolated from the liver, gills, fins and muscle of Clarias gariepinus. Methods. Glutathione S-transferase, catalase, rhodanese and 3-mercaptopyruvate S-transferase enzymes were isolated from the liver and gills of fish by homogenization of each tissue (with specific buffers for each enzyme) and centrifugation. Serial dilutions of the crude enzymes were then assayed for residual enzymatic activities using standard enzyme assay protocol. Results. The results showed heavy metals in the liver and muscle of the investigated fish. This study indicated significant accumulation of heavy metals in the tissues/organ of the fish from Ilesha, Osogbo and Yakoyo fish ponds. These are three main towns in Osun State where the major occupation is fish farming. The relationship between enzymatic activities and heavy metal content in C gariepinus tissue showed positive and significant (p

The study investigated the biochemical characteristics and kinetic parameters of laccase from a newly isolated Aureobasidium pullulans NAC8 obtained from soil containing decay plant litters. This was with a view to identifying the type of laccase and its possible suitability for biotechnological applications. The fungal strain was identified as A. pullulans NAC8 by sequencing of its 5.8S rRNA and adjacent internally transcribed sequences (ITS) 1 and 2. A. pullulans NAC8 laccase was purified 2.0-fold with a yield of 59.3% and specific activity of 9.34 μmol/min/mg protein. The kinetic parameters KM, Vmax, kcat and kcat/KM for laccase with guaiacol as substrate were 1.05 ± 0.12 mM, 12.67 ± 0.55 μmol/ml/min, 25.3 × 10−1 s−1 and 2.4 × 103 M−1 s−1 respectively. Laccase exhibited maximum activity at 45 °C and optimum pH of 4.5. The enzyme showed stability at a temperature range of 45–55 °C after a 2 h incubation. The molecular weight determined on SDS–PAGE was 68.4 kDa. The enzyme was stable at 10% of all organic solvents used but displayed a loss of activity at 50%. 2.5 mM thioglycolic acid (TGA) and 0.05 mM sodium azide inactivated the enzyme. The substrate specificity was guaiacol > catechol > tannic acid > gallic acid. There was no peak observed at 610 nm and the ratio of absorbance at 280 nm and 610 was 26. This suggests a yellow laccase. The biochemical properties of A. pullulans NAC8 yellow laccase makes it potentially useful in several biotechnological applications.

Background. Heavy metals in water systems are a human health concern as they can enter the food chain. Objectives. Heavy metal and particle size determinations were used to determine the sediment quality of three fishponds in Osun State, Nigeria and their feeder streams. Methods. Sediment samples were collected in triplicates from the streams and their associated fishponds and the accumulations of nine heavy metals (lead (Pb), cobalt (Co), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), iron (Fe), manganese (Mg), zinc (Zn)) in the sediment were investigated seasonally. Particle size distribution and textural class of the samples were also determined. Results. Metal concentrations recorded in bottom sediment varied widely and exhibited fluctuations among the different ponds and streams, especially in the values of Fe, Cu, Mn, Cr, Zn and Pb. There was a significant difference (pCu>Ni>Zn>Pb>Cr>Mn>Co in Ilesha, Fe>Cu>Ni>Zn>Mn>Co>Pb>Cr in Osogbo and Zn>Fe>Ni>Mn>Cu>Co>Cr>Pb in Yakoyo. A closely related order of Fe>Mn>Ni>Zn>Cr>Cu>Se>Pb>Mo>Cd was observed in River Eku. The selected streams and their associated fishponds were fairly polluted, with the Yah fishpond (Ilesha) having the highest heavy metal pollution compared to Arula fishpond (Osogbo) and Ewuru/Rara fishpond (Yakoyo). The concentrations of accumulated heavy metals depended on the textural class of the sediment. Conclusion. Pollution has reached levels hazardous to human health compared to standard limits for aquaculture development. Stream and fishpond sediments should be analyzed at regular intervals as a quality assurance process to ensure that there are no toxic substances in the ponds, leading to possible bio-accumulation and magnification. This will help guarantee the health of the aquatic ecosystem, humans and the environment. Competing Interests. The authors declare no competing financial interests.