Effects of hydrocarbon contamination on soil microbial community and enzyme activity

Acknowledgment I would like to gratefully acknowledge the government of Saudi Arabia for the scholarship and financial support.Peer reviewedPublisher PD

Antimicrobial activities and phytochemical analysis of leaf extracts of Echinops abuzinadianus Chaudhary growing in Abha City, Saudi Arabia

Echinops abuzinadianus belongs to the sunflower or Asteraceae family, which is widely found in an abandoned area in Abha city in Saudi Arabia. The properties of this endemic plant have not been yet researched. This study used agar well diffusion methods to investigatethe antimicrobial inhibition activity of solvent-extracted dry and fresh E. abuzinadianus leaves against some human pathogenic microbes. The results show that almost all solvent extracts had significant inhibitory activity against Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Micrococcus luteus and Candida albicans. Fresh leaf-extract had more potent activity against all tested microorganisms than dry leaf-extract. The maximum antibacterial activity against S. Flexneri was gained from methanol extract, chloroform extracts against Pseudomonas aeruginosa, diethyl ether extracts against K. pneumoniae and acetone extract against C. albicans. Petroleum ether extract showed moderate antibacterial activities against P. mirabilis, while petroleum ether extract exhibited the minimum antibacterial activity against K. pneumonia. Gas chromatography mass spectrometry (GC-MS) showed the presence of five phytochemical compounds: palmitic acid (the most dominant compound), followed by 9-octadecenoic acid, octadecatrienoic acid, and trace quantities ofoctadeca-9,12,15-trienoic acid and phytol. The inhibition of the microbial growth in the presence of solvent extracts of E. abuzinadianus leaves and the secondary metabolites produced by the plants, make it a promising medicinal plant

Variations in genetic and chemical constituents of Ziziphus spina-christi L. populations grown at various altitudinal zonation up to 2227m height

AbstractAltitudinal gradient-defined specific environmental conditions could lead to genetics and chemical variations among individuals of the same species. By using RAPD, ISSR, GC–MS and HPLC analysis, the genetic and chemical diversity of Ziziphus spina-christi plants at various altitudinal gradient namely; Abha (2227.86m), Dala Valley (1424m), Rakhma Valley (1000m), Raheb Valley (505m) and Al-Marbh (147m) were estimated. RAPD markers revealed that the highest similarity value (40.22%) was between Raheb Valley and Al-Marbh while the lowest similarity (10.08%) was between Abha and Raheb Valley. Based on ISSR markers the highest similarity value (61.54%) was also between Raheb Valley and Al-Marbh, while the lowest similarity (26.84%) was between Abha and Rakhma Valley. GC–MS results showed the presence of various phytochemical constituents in each population. The dendrogram based on chemical compounds separated the Z. spina-christi grown at the highest elevations (Abha) from the populations in lower elevations. HPLC analysis showed that the leaves of Z. spina-christi plant contain considerable amount of vitamins including B1, B12, B2 and folic acid. In conclusion, there is a close relation between altitudinal gradients, genetic diversity and chemical constituents of the leaves of Z. spina-christi plants

Isolation of Thermoalkalophilic-?-amylase Producing Bacteria and Optimization of Potato Waste Water Medium for Enhancement of ?-amylase Production

Sixty one thermoalkalophilic bacteria were isolated from soil samples in Saudi Arabia’s southern region. Isolate TA-38, obtained from the Tanomah region, showed the best performance for enzyme production and was submitted for further study. It was identified as Bacillus axarquiensis based on 16S rRNA gene sequencing studies. The feasibility of using potato waste water as a simple and cheap medium for the production of ?-amylase was evaluated compared with starch broth medium. The production of ?-amylase in the potato waste water medium was only 13.8% less than that of the starch medium. Maximum enzyme production was achieved after 48 hours of cultivation at the beginning of the stationary phase at pH 10.0 and 50 0C. The appropriate addition of starch; nitrogen; phosphate; and calcium to potato waste water significantly enhanced the production of ?-amylase. The enzyme production reached a maximum of 64.5 Uml-1 with the potato wastewater adding with 0.5 % starch; 0.4 % yeast extract; 0.04% CaCl2-2H2O and 0.05 % KH2PO4.  The optimization of the potato waste water medium led to an approximately 4.02 fold increase in the production of ?-amylase compared to starch broth medium. Data indicated that the potato waste water contained substrates which could be used by bacterial isolate for the production of ?-amylase production and the developed procedure was cost effective since it requires only a slightly addition of nutrients to the medium. Keywords: Isolation; ?-amylase; 16S rRNA; Production; Potato waste water; Thermoalkaliphilic bacteria

Fungal-mediated synthesis of silver nanoparticles: a novel strategy for plant disease management

Various traditional management techniques are employed to control plant diseases caused by bacteria and fungi. However, due to their drawbacks and adverse environmental effects, there is a shift toward employing more eco-friendly methods that are less harmful to the environment and human health. The main aim of the study was to biosynthesize silver Nanoparticles (AgNPs) from Rhizoctonia solani and Cladosporium cladosporioides using a green approach and to test the antimycotic activity of these biosynthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV–visible spectroscopy, SEM (scanning electron microscopy), FTIR (fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). During the study, the presence of strong plasmon absorbance bands at 420 and 450 nm confirmed the AgNPs biosynthesis by the fungi Rhizoctonia solani and Cladosporium cladosporioides. The biosynthesized AgNPs were 80–100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Assessment of the antifungal activity of the silver nanoparticles against various plant pathogenic fungi was carried out by agar well diffusion assay. Different concentration of AgNPs, 5 mg/mL 10 mg/mL and 15 mg/mL were tested to know the inhibitory effect of fungal plant pathogens viz. Aspergillus flavus, Penicillium citrinum, Fusarium oxysporum, Fusarium metavorans, and Aspergillus aflatoxiformans. However, 15 mg/mL concentration of the AgNPs showed excellent inhibitory activity against all tested fungal pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi

Prediction Models Based on Soil Characteristics for Evaluation of the Accumulation Capacity of Nine Metals by Forage Sorghum Grown in Agricultural Soils Treated with Varying Amounts of Poultry Manure

Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF)  1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.The authors extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia for funding this research work through the project number IFP-KKU-2020/3.Peer reviewe

Microbial ecotoxicological assessment of hydrocarbon impacted soils undergone [sic] remediation

Hydrocarbon contamination of soils has increased worldwide and bioremediation offers an attractive and environmentally friendly solution to this problem. However, the efficiency and completion of remediation must be assessed using environmental risk assessment criteria. As a result, a variety of indicators have become essential for determining and evaluating recovery of contaminated soils. In this study, microbiological and toxicological assays are used to support traditional chemical analyses, to identify a suite of assays suitable for determining a Soil Recovery Index from Pollution (SRIP). Microbiological assays used are microbial biomass carbon (Cmic), plate counts for culturable degraders and general heterotrophs enzyme activities (dehydrogenase and phosphatase), basal respiration, Substrate Induced Respiration (SIR), and bacterial biosensor. Toxicological response assays of higher organisms include two species of earthworms (Eisenia fetida and Lumbricus terrestris), also, plant assays, including seed germination, root elongation, germination index and plant shoot height performed using two species of plant wheat (Triticum aestivum L.) and white mustard (Brassica alba L.). All assays were applied sequentially to kerosene and diesel amended soils for both incubated and non–incubated treatments. The indicators were discriminated in terms of their sensitivity using a ranking system. The data collected were integrated into a single numeric value to reflect a ‘level of concern’ for each soil treatment. Soil characteristics and hydrocarbon types play key roles in the response of these indicators. The soil that had high organic matter and clay content was less affected by hydrocarbons. For the freshly hydrocarbon amended soils, kerosene was more toxic than diesel, however the opposite was found in the incubated hydrocarbon amended treatments. The most sensitive and robust indicators were basal respiration, bacterial heterotrophs and degraders counts, bacterial biosensors (methanol extracted soils), earthworm survival, mustard root elongation and mustard plant shoot height. Sensitive indicators were inserted into the SRIP. The SRIP indicates the “level of concern” for each soil treatment in a single value.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Enzymatic saccharification and fermentation of cellulosic date palm wastes to glucose and lactic acid

Abstract The bioconversion of cellulosic wastes into high-value bio-products by saccharification and fermentation processes is an important step that can reduce the environmental pollution caused by agricultural wastes. In this study, enzymatic saccharification of treated and untreated date palm cellulosic wastes by the cellulases from Geobacillus stearothermophilus was optimized. The alkaline pre-treatment of the date palm wastes was found to be effective in increasing the saccharification percentage. The maximum rate of saccharification was found at a substrate concentration of 4% and enzyme concentration of 30 FPU/g of substrate. The optimum pH and temperature for the bioconversions were 5.0 and 50 °C, respectively, after 24 h of incubation, with a yield of 31.56 mg/mL of glucose at a saccharification degree of 71.03%. The saccharification was increased to 94.88% by removal of the hydrolysate after 24 h by using a two-step hydrolysis. Significant lactic acid production (27.8 mg/mL) was obtained by separate saccharification and fermentation after 72 h of incubation. The results indicate that production of fermentable sugar and lactic acid is feasible and may reduce environmental pollution by using date palm wastes as a cheap substrate

Antimicrobial activities and phytochemical analysis of leaf extracts of Echinops abuzinadianus Chaudhary growing in Abha City, Saudi Arabia

802-807Echinops abuzinadianus belongs to the sunflower or Asteraceae family, which is widely found in an abandoned area in Abha city in Saudi Arabia. The properties of this endemic plant have not been yet researched. This study used agar well diffusion methods to investigatethe antimicrobial inhibition activity of solvent-extracted dry and fresh E. abuzinadianus leaves against some human pathogenic microbes. The results show that almost all solvent extracts had significant inhibitory activity against Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Micrococcus luteus and Candida albicans. Fresh leaf-extract had more potent activity against all tested microorganisms than dry leaf-extract. The maximum antibacterial activity against S. Flexneri was gained from methanol extract, chloroform extracts against Pseudomonas aeruginosa, diethyl ether extracts against K. pneumoniae and acetone extract against C. albicans. Petroleum ether extract showed moderate antibacterial activities against P. mirabilis, while petroleum ether extract exhibited the minimum antibacterial activity against K. pneumonia. Gas chromatography mass spectrometry (GC-MS) showed the presence of five phytochemical compounds: palmitic acid (the most dominant compound), followed by 9-octadecenoic acid, octadecatrienoic acid, and trace quantities of octadeca-9,12,15-trienoic acid and phytol. The inhibition of the microbial growth in the presence of solvent extracts of E. abuzinadianus leaves and the secondary metabolites produced by the plants, make it a promising medicinal plant

Exposure of Pisum&nbsp;sativum L. Seeds to Methomyl and Imidacloprid Cause Genotoxic Effects in Pollen-Mother Cells

Pesticides are commonly used in modern agricultural systems to protect the plants from pests. Even though they potentially increase the crop yield, they have undesirable toxic effects on the consumers of plant products and nontarget host plants. However, there are limited studies to demonstrate the cytological changes induced by pesticides on plant cells. In the present study, we assess the cytological changes induced by two most commonly used insecticides, methomyl (ME) and imidacloprid (IM), using Pisum sativum L. as model plant system. P. sativum seeds were exposed to various concentrations of ME and IM (0.1, 0.2, 0.3, 0.4 and 0.5%) for 1, 3, and 6 h, and their effects on seed germination (SG), radicle length (RL), mitotic index (MI), chromosomal aberrations frequency (CAF), and micronucleus frequency (MNF) were studied. The results indicate that these insecticides decrease MI in root-tip cells, and increase in the MNF in pollen-mother cells in a dose-dependent manner. Additionally, insecticide-treated groups showed a dose- and time-dependent increase in the percentage of aberrant meiotic cells. Clumped nuclei (CNU), stickiness (STC), bridges (BRs), laggards (LGs), secondary association (SA), and precocious separation (PS) were among the frequently observed anomalies. The findings of this study indicate that commonly used insecticides ME and IM have substantial genotoxic effects on the root-tip and pollen-mother cells of P. sativum L