Biosorption of heavy metals by Bacillus thuringiensis strain OSM29 originating from industrial effluent contaminated north Indian soil

AbstractThe study was navigated to examine the metal biosorbing ability of bacterial strain OSM29 recovered from rhizosphere of cauliflower grown in soil irrigated consistently with industrial effluents. The metal tolerant bacterial strain OSM29 was identified as Bacillus thuringiensis following 16S rRNA gene sequence analysis. In the presence of the varying concentrations (25–150mgl−1) of heavy metals, such as cadmium, chromium, copper, lead and nickel, the B. thuringiensis strain OSM29 showed an obvious metal removing potential. The effect of certain physico-chemical factors such as pH, initial metal concentration, and contact time on biosorption was also assessed. The optimum pH for nickel and chromium removal was 7, while for cadmium, copper and lead, it was 6. The optimal contact time was 30min. for each metal at 32±2°C by strain OSM29. The biosorption capacity of the strain OSM29 for the metallic ions was highest for Ni (94%) which was followed by Cu (91.8%), while the lowest sorption by bacterial biomass was recorded for Cd (87%) at 25mgl−1 initial metal ion concentration. The regression coefficients obtained for heavy metals from the Freundlich and Langmuir models were significant. The surface chemical functional groups of B. thuringiensis biomass identified by Fourier transform infrared (FTIR) were amino, carboxyl, hydroxyl, and carbonyl groups, which may be involved in the biosorption of heavy metals. The biosorption ability of B. thuringiensis OSM29 varied with metals and was pH and metal concentration dependent. The biosorption of each metal was fairly rapid which could be an advantage for large scale treatment of contaminated sites

Bacterial ACC deaminase: Insights into enzymology, biochemistry, genetics, and potential role in amelioration of environmental stress in crop plants

Growth and productivity of crop plants worldwide are often adversely affected by anthropogenic and natural stresses. Both biotic and abiotic stresses may impact future food security and sustainability; global climate change will only exacerbate the threat. Nearly all stresses induce ethylene production in plants, which is detrimental to their growth and survival when present at higher concentrations. Consequently, management of ethylene production in plants is becoming an attractive option for countering the stress hormone and its effect on crop yield and productivity. In plants, ACC (1-aminocyclopropane-1-carboxylate) serves as a precursor for ethylene production. Soil microorganisms and root-associated plant growth promoting rhizobacteria (PGPR) that possess ACC deaminase activity regulate growth and development of plants under harsh environmental conditions by limiting ethylene levels in plants; this enzyme is, therefore, often designated as a “stress modulator.” TheACC deaminase enzyme, encoded by the AcdS gene, is tightly controlled and regulated depending upon environmental conditions. Gene regulatory components of AcdS are made up of the LRP protein-coding regulatory gene and other regulatory components that are activated via distinct mechanisms under aerobic and anaerobic conditions. ACC deaminase-positive PGPR strains can intensively promote growth and development of crops being cultivated under abiotic stresses including salt stress, water deficit, waterlogging, temperature extremes, and presence of heavy metals, pesticides and other organic contaminants. Strategies for combating environmental stresses in plants, and improving growth by introducing the acdS gene into crop plants via bacteria, have been investigated. In the recent past, some rapid methods and cutting-edge technologies based on molecular biotechnology and omics approaches involving proteomics, transcriptomics, metagenomics, and next generation sequencing (NGS) have been proposed to reveal the variety and potential of ACC deaminase-producing PGPR that thrive under external stresses. Multiple stress-tolerant ACC deaminase-producing PGPR strains have demonstrated great promise in providing plant resistance/tolerance to various stressors and, therefore, it could be advantageous over other soil/plant microbiome that can flourish under stressed environments

Human knockouts and phenotypic analysis in a cohort with a high rate of consanguinity

A major goal of biomedicine is to understand the function of every gene in the human genome. Loss-of-function mutations can disrupt both copies of a given gene in humans and phenotypic analysis of such 'human knockouts' can provide insight into gene function. Consanguineous unions are more likely to result in offspring carrying homozygous loss-of-function mutations. In Pakistan, consanguinity rates are notably high. Here we sequence the protein-coding regions of 10,503 adult participants in the Pakistan Risk of Myocardial Infarction Study (PROMIS), designed to understand the determinants of cardiometabolic diseases in individuals from South Asia. We identified individuals carrying homozygous predicted loss-of-function (pLoF) mutations, and performed phenotypic analysis involving more than 200 biochemical and disease traits. We enumerated 49,138 rare (<1% minor allele frequency) pLoF mutations. These pLoF mutations are estimated to knock out 1,317 genes, each in at least one participant. Homozygosity for pLoF mutations at PLA2G7 was associated with absent enzymatic activity of soluble lipoprotein-associated phospholipase A2; at CYP2F1, with higher plasma interleukin-8 concentrations; at TREH, with lower concentrations of apoB-containing lipoprotein subfractions; at either A3GALT2 or NRG4, with markedly reduced plasma insulin C-peptide concentrations; and at SLC9A3R1, with mediators of calcium and phosphate signalling. Heterozygous deficiency of APOC3 has been shown to protect against coronary heart disease; we identified APOC3 homozygous pLoF carriers in our cohort. We recruited these human knockouts and challenged them with an oral fat load. Compared with family members lacking the mutation, individuals with APOC3 knocked out displayed marked blunting of the usual post-prandial rise in plasma triglycerides. Overall, these observations provide a roadmap for a 'human knockout project', a systematic effort to understand the phenotypic consequences of complete disruption of genes in humans.D.S. is supported by grants from the National Institutes of Health, the Fogarty International, the Wellcome Trust, the British Heart Foundation, and Pfizer. P.N. is supported by the John S. LaDue Memorial Fellowship in Cardiology from Harvard Medical School. H.-H.W. is supported by a grant from the Samsung Medical Center, Korea (SMO116163). S.K. is supported by the Ofer and Shelly Nemirovsky MGH Research Scholar Award and by grants from the National Institutes of Health (R01HL107816), the Donovan Family Foundation, and Fondation Leducq. Exome sequencing was supported by a grant from the NHGRI (5U54HG003067-11) to S.G. and E.S.L. D.G.M. is supported by a grant from the National Institutes of Health (R01GM104371). J.D. holds a British Heart Foundation Chair, European Research Council Senior Investigator Award, and NIHR Senior Investigator Award. The Cardiovascular Epidemiology Unit at the University of Cambridge, which supported the field work and genotyping of PROMIS, is funded by the UK Medical Research Council, British Heart Foundation, and NIHR Cambridge Biomedical Research Centre ... Fieldwork in the PROMIS study has been supported through funds available to investigators at the Center for Non-Communicable Diseases, Pakistan and the University of Cambridge, UK

Effects of pesticides on plant growth promoting traits of Mesorhizobium strain MRC4

The objective of this study was to assess the effect of selected pesticides [herbicides (metribuzin and glyphosate), insecticides (imidacloprid and thiamethoxam) and fungicides (hexaconazole, metalaxyl and kitazin)] at recommended and higher dose rates on plant growth promoting activities of the Mesorhizobium sp. isolated from chickpea-nodules. A total of 50 rhizobial strains recovered from the nodules of chickpea root systems were identified following morphological, biochemical and host-specificity tests and tested for pesticide-tolerance. Among these strains, the Mesorhizobium sp. strain MRC4 was specifically selected due to the highest tolerance levels for all selected pesticides and the maximum production of plant growth promoting substances. Strain MRC4 produced indole acetic acid (44 μg ml−1), siderophores [salicylic acid (35 μg ml−1) and 2,3-dihydroxy benzoic acid (19 μg ml−1)], exo-polysaccharides (21 μg ml−1), HCN and ammonia. Under pesticide-stress, pesticide-concentration dependent progressive-decline in all plant growth promoting traits of the Mesorhizobium sp. strain MRC4 exposed was observed except for exo-polysaccharides which consistently increased with exceeding the concentration of each pesticide from recommended dose. For instance, hexaconazole at three times the recommended dose elicited the maximum stress on siderophore-biosynthesis by the Mesorhizobium sp. strain MRC4 and decreased salicylic acid and DHBA by 40% and 47%, respectively and the greatest stimulatory effect on exo-polysaccharides secretion was shown by imidacloprid which stimulated the Mesorhizobium sp. strain MRC4 to secrete EPS by 38%, compared to control. Generally, the maximum toxicity to plant growth promoting traits of Mesorhizobium was shown by glyphosate, thiamethoxam and hexaconazole, at three times the recommended rate among herbicides, insecticides and fungicides, respectively. This study revealed an additional aspect of the toxicological mechanisms of the pesticides through which they suppress the plant growth

Toxicological assessment of selective pesticides towards plant growth promoting activities of phosphate solubilizing Pseudomonas aeruginosa

The study was designed to assess the effect of selected pesticides (metribuzin, glyphosate, imidacloprid, thiamethoxam, hexaconazole, metalaxyl and kitazin) at the recommended and higher rates on plant growth promoting activities of Pseudomonas aeruginosa strain PS1 isolated from mustard (Brassica compestris) rhizosphere. The strain PS1 was specifically chosen owing to its substantial tolerance against pesticides, phosphate solubilization and considerable production of indole acetic acid, siderophores, exo-polysaccharides, HCN and ammonia. Plant growth promoting traits of the strain PS1 decreased consistently as the concentrations of each pesticide was increased from the recommended dose to the higher ones. Generally, the maximum toxicity to plant growth promoting traits was displayed by pesticides at three times the recommended field rate. However, the effect on the plant growth promoting activities of the P. aeruginosa strain PS1 at the recommended dose of each pesticide was less hazardous. This study revealed an additional aspect of the toxicological mechanisms of the pesticides through which they suppress the plant growth

Metabolomics-Based Mechanistic Insights into Revealing the Adverse Effects of Pesticides on Plants: An Interactive Review

In plant biology, metabolomics is often used to quantitatively assess small molecules, metabolites, and their intermediates in plants. Metabolomics has frequently been applied to detect metabolic alterations in plants exposed to various biotic and abiotic stresses, including pesticides. The widespread use of pesticides and agrochemicals in intensive crop production systems is a serious threat to the functionality and sustainability of agroecosystems. Pesticide accumulation in soil may disrupt soil&ndash;plant relationships, thereby posing a pollution risk to agricultural output. Application of metabolomic techniques in the assessment of the biological consequences of pesticides at the molecular level has emerged as a crucial technique in exposome investigations. State-of-the-art metabolomic approaches such as GC&ndash;MS, LC&ndash;MS/MS UHPLC, UPLC&ndash;IMS&ndash;QToF, GC/EI/MS, MALDI-TOF MS, and 1H-HR-MAS NMR, etc., investigating the harmful effects of agricultural pesticides have been reviewed. This updated review seeks to outline the key uses of metabolomics related to the evaluation of the toxicological impacts of pesticides on agronomically important crops in exposome assays as well as bench-scale studies. Overall, this review describes the potential uses of metabolomics as a method for evaluating the safety of agricultural chemicals for regulatory applications. Additionally, the most recent developments in metabolomic tools applied to pesticide toxicology and also the difficulties in utilizing this approach are discussed

Cadmium, chromium and copper in greengram plants

Soils contaminated with heavy metals including cadmium, chromium and copper present a major concern for sustainable agriculture. We studied the effects of cadmium, chromium and copper used both separately and as mixtures, on plant growth, nodulation, leghaemoglobin, seed yield and grain protein in seeds, in greengram inoculated with Bradyrhizobium sp. (Vigna). Cadmium at 24 mg kg$^{-1}$ of soil reduced the dry matter accumulation and number of nodules by 27 and 38%, respectively. Chromium at 136 mg kg$^{-1}$of soil increased the dry phytomass and nodule numbers by 133 and 100%, respectively. The average maximum increase of 74% in seed yield occurred at 136 mg Cr kg$^{-1}$ of soil. Cadmium and copper at 24 and 1338 mg kg$^{-1}$ soil decreased the seed yield by 40 and 26%, respectively. Chromium at 136 kg$^{-1}$ of soil increased the root and shoot N and leghaemoglobin content by 42, 31% and 50%, respectively. In contrast, the root and shoot N decreased by 22% at 24 mg Cd kg$^{-1}$ of soil, while a maximum decrease of 50% in leghaemoglobin content occurred at 12 and 669 and 24 and 1338 mg Cd with Cu kg$^{-1}$ of soil, relative to the control. The average maximum grain protein (283 mg g$^{-1})$ was observed at 136 mg Cr kg$^{-1}$ of soil, while minimum grain protein (231 mg g$^{-1})$ was recorded at 24 and 1338 mg kg$^{-1}$ of cadmium with copper. The metal accumulation in roots and shoots at 50 days after sowing and in grains 80 days after seeding differed among treatments. The degree of toxicity of heavy metals to the measured parameters decreased in the order Cd $>$ Cu $>$ Cr

Role of phosphate-solubilizing microorganisms in sustainable agriculture – A review

Compared with the other major nutrients, phosphorus is by far the least mobile and available to plants in most soil conditions. Although phosphorus is abundant in soils in both organic and inorganic forms, it is frequently a major or even the prime limiting factor for plant growth. The bioavailability of soil inorganic phosphorus in the rhizosphere varies considerably with plant species, nutritional status of soil and ambient soil conditions. To circumvent phosphorus deficiency, phosphate-solubilizing microorganisms (PSM) could play an important role in supplying phosphate to plants in a more environmentally-friendly and sustainable manner. The solubilization of phosphatic compounds by naturally abundant PSM is very common under in vitro conditions; the performance of PSM in situ has been contradictory. The variability in the performance has thus greatly hampered the large-scale application of PSM in sustainable agriculture. Numerous reasons have been suggested for this, but none of them have been conclusively investigated. Despite the variations in their performance, PSM are widely applied in agronomic practices in order to increase the productivity of crops while maintaining the health of soils. This review presents the results of studies on the utilization of PSM for direct application in agriculture under a wide range of agro-ecological conditions with a view to fostering sustainable agricultural intensification in developing countries of the tropics and subtropics

Consumer Behavior towards E-commerce during Pre and Post-Covid-19 in Aligarh: A Comparative Analysis

Purpose: The purpose of the study is to find out consumer behaviour towards e-commerce during the pre and post-covid-19 period in Aligarh. Research Design: This research paper is based on the primary data collected through self-administered questionnaires through snowball sampling. The Chi-Square test is used to calculate the change between the consumers’ pre and post covid-19 behaviour for the use of e-commerce. Findings: This study found that the overall use of e-commerce has increased, while Phone pay and Amazon use for transaction purposes have increased, and the use of Amazon has increased for shopping purposes substantially. This study has also found that e-commerce has increased substantially for transactions and food purchases. The main reasons for shifting toward e-commerce are social distancing, ease of use, digital transactions, and the physical scarcity of goods at the nearest stores. Research Limit: This research is conducted in Aligarh City. The results of the research can be applied in Aligarh City only. Originality/Value: This research will help understand the reason for the use and non-use of the e-commerce platform for e-commerce companies. It will help them understand the consumers’ thoughts to change their business strategy substantially in Aligarh city and tier II cities like Aligarh

Psychrophilic Bacterial Phosphate-Biofertilizers: A Novel Extremophile for Sustainable Crop Production under Cold Environment

Abiotic stresses, including low-temperature environments, adversely affect the structure, composition, and physiological activities of soil microbiomes. Also, low temperatures disturb physiological and metabolic processes, leading to major crop losses worldwide. Extreme cold temperature habitats are, however, an interesting source of psychrophilic and psychrotolerant phosphate solubilizing bacteria (PSB) that can ameliorate the low-temperature conditions while maintaining their physiological activities. The production of antifreeze proteins and expression of stress-induced genes at low temperatures favors the survival of such organisms during cold stress. The ability to facilitate plant growth by supplying a major plant nutrient, phosphorus, in P-deficient soil is one of the novel functional properties of cold-tolerant PSB. By contrast, plants growing under stress conditions require cold-tolerant rhizosphere bacteria to enhance their performance. To this end, the use of psychrophilic PSB formulations has been found effective in yield optimization under temperature-stressed conditions. Most of the research has been done on microbial P biofertilizers impacting plant growth under normal cultivation practices but little attention has been paid to the plant growth-promoting activities of cold-tolerant PSB on crops growing in low-temperature environments. This scientific gap formed the basis of the present manuscript and explains the rationale for the introduction of cold-tolerant PSB in competitive agronomic practices, including the mechanism of solubilization/mineralization, release of biosensor active biomolecules, molecular engineering of PSB for increasing both P solubilizing/mineralizing efficiency, and host range. The impact of extreme cold on the physiological activities of plants and how plants overcome such stresses is discussed briefly. It is time to enlarge the prospects of psychrophilic/psychrotolerant phosphate biofertilizers and take advantage of their precious, fundamental, and economical but enormous plant growth augmenting potential to ameliorate stress and facilitate crop production to satisfy the food demands of frighteningly growing human populations. The production and application of cold-tolerant P-biofertilizers will recuperate sustainable agriculture in cold adaptive agrosystems