Showing papers by "Ali H. Bahkali published in 2021"

Co-inoculation of rhizobacteria promotes growth, yield, and nutrient contents in soybean and improves soil enzymes and nutrients under drought conditions.

Abstract: Drought stress is the major abiotic factor limiting crop production. Co-inoculating crops with nitrogen fixing bacteria and plant growth-promoting rhizobacteria (PGPR) improves plant growth and increases drought tolerance in arid or semiarid areas. Soybean is a major source of high-quality protein and oil for humans. It is susceptible to drought stress conditions. The co-inoculation of drought-stressed soybean with nodulating rhizobia and root-colonizing, PGPR improves the root and the shoot growth, formation of nodules, and nitrogen fixation capacity in soybean. The present study was aimed to observe if the co-inoculation of soybean (Glycine max L. (Merr.) nodulating with Bradyrhizobium japonicum USDA110 and PGPR Pseudomonas putida NUU8 can enhance drought tolerance, nodulation, plant growth, and nutrient uptake under drought conditions. The results of the study showed that co-inoculation with B. japonicum USDA110 and P. putida NUU8 gave more benefits in nodulation and growth of soybean compared to plants inoculated with B. japonicum USDA110 alone and uninoculated control. Under drought conditions, co-inoculation of B. japonicum USDA 110 and P. putida NUU8 significantly enhanced the root length by 56%, shoot length by 33%, root dry weight by 47%, shoot dry weight by 48%, and nodule number 17% compared to the control under drought-stressed. Co-inoculation with B. japonicum, USDA 110 and P. putida NUU8 significantly enhanced plant and soil nutrients and soil enzymes compared to control under normal and drought stress conditions. The synergistic use of B. japonicum USDA110 and P. putida NUU8 improves plant growth and nodulation of soybean under drought stress conditions. The results suggested that these strains could be used to formulate a consortium of biofertilizers for sustainable production of soybean under drought-stressed field conditions.

Inoculation of Klebsiella variicola Alleviated Salt Stress and Improved Growth and Nutrients in Wheat and Maize

Abstract: Although wheat and maize are the major economically important cereal crops and staple food sources in the world, their productivity is highly affected by excess salts in soil (salinity). Applications of multifarious halophilic plant growth-promoting rhizobacteria (PGPR) in saline soil protect the plants from osmotic damages and promote plant growth through the secretion of plant growth promoting (PGP) and osmolytes. In this study, Klebsiella variicola SURYA6—a PGPR—was evaluated for plant-growth-promotion and salinity amelioration in wheat and maize, and enrichment of soil nutrients. The results of the present study revealed that K. variicola SURYA6 grows luxuriously under high salinity stress conditions and produces copious amounts of three principal salinity ameliorating traits, such as 1 aminocyclopropane-1-carboxylate deaminase (ACCD), indole-3-acetic acid (IAA), exopolysaccharides (EPS), and osmolytes—such as proline, sugars, proteins, and amino acids. The isolate also exhibited sensitivity to a wide range of antibiotics, lack of hemolytic ability, and absence of catalase and oxidase activities confirming its nonpathogenic nature. Inoculation of wheat and maize seeds with this multifarious strain, improved the physicochemical properties of soil, improved seed germination by 33.9% and 36.0%, root length by 111.0%, 35.1%, shoot height by 64.8% and 78.9%, and chlorophyll content by 68.4% and 66.7% in wheat and maize seedlings, respectively, at 45 days after sowing (DAS) under salinity stress. The improvement in plant growth can be correlated with the secretion of PGP traits and improved, uptake of minerals such as nitrogen (N), phosphorus (P), sodium (Na), potassium (K), and magnesium (Mg). While amelioration of salinity can be the result of secretion of osmolytes and the change in pH from salinity to neutrality. This inoculation also significantly improved the soil nutrients under salinity stress conditions. Inoculation of K. variicola SURYA6, resulted in more improved growth and nutrients contents in plants and enriched soil nutrients under salinity stress as compared to normal (non-saline) conditions. Such multifarious strain can serve as a potent bio-inoculant for growth promotion of wheat and maize in saline soil. However, multi-year field trials under different agro-climatic conditions are required to confirm the bio-efficacy of K. variicola SURYA6.

PGMD/curcumin nanoparticles for the treatment of breast cancer.

Abstract: The present study aims at developing PGMD (poly-glycerol-malic acid-dodecanedioic acid)/curcumin nanoparticles based formulation for anticancer activity against breast cancer cells. The nanoparticles were prepared using both the variants of PGMD polymer (PGMD 7:3 and PGMD 6:4) with curcumin (i.e. CUR NP 7:3 and CUR NP 6:4). The size of CUR NP 7:3 and CUR NP 6:4 were found to be ~ 110 and 218 nm with a polydispersity index of 0.174 and 0.36, respectively. Further, the zeta potential of the particles was - 18.9 and - 17.5 mV for CUR NP 7:3 and CUR NP 6:4, respectively. The entrapment efficiency of both the nanoparticles was in the range of 75-81%. In vitro anticancer activity and the scratch assay were conducted on breast cancer cell lines, MCF-7 and MDA-MB-231. The IC50 of the nanoformulations was observed to be 40.2 and 33.6 μM at 48 h for CUR NP 7:3 and CUR NP 6:4, respectively, in MCF-7 cell line; for MDA-MB-231 it was 43.4 and 30.5 μM. Acridine orange/EtBr and DAPI staining assays showed apoptotic features and nuclear anomalies in the treated cells. This was further confirmed by western blot analysis that showed overexpression of caspase 9 indicating curcumin role in apoptosis.

Occurrence and geographical distribution of mangrove fungi

Abstract: This is a multidimensional review of mangrove fungi occurring as saprobes, pathogens and endophytes of a wide range of host substrates and those isolated from the water columns and sediments in mangroves. Eight-hundred and fifty taxa including 658 that are supported by both morphology and molecular data and 192 with only morphological data are listed. These constitute Ascomycota, the dominant group with 773 species, and 58 Basidiomycota, one Blastocladiomycota, five Chytridiomycota, and 13 Mucoromycota. This study also includes data on mangrove yeasts 103 Ascomycota, 39 Basidiomycota and 193 taxa isolated from sediments. Endophytes isolated from submerged parts of mangrove plants total 38. The most specious orders of mangrove fungi are Pleosporales 133, Saccharomycetales 102, Microascales 101, Eurotiales 87, Hypocreales 60 and Xylariales 54. Speciose genera include Candida 39, Aspergillus 53, Penicillium 17 and Corollospora 16. The highest number of mangrove fungi have been recorded from the Pacific Ocean 553, which is the largest ocean, followed by Indian 408 and Atlantic Oceans 259. Geographical distribution of mangrove fungi varied from ocean to ocean with only 109 taxa common to the Atlantic, Indian and Pacific Oceans. Of the various countries reported for mangrove fungi, India accommodates the highest number (339) followed by Thailand 303, Malaysia 171, Florida Everglades, USA 134 and Brunei 134. A total of 60 different mangrove plants and their associates have been surveyed for mangrove fungi. These results are discussed and compared with previous studies.

Drought Tolerant Enterobacter sp./Leclercia adecarboxylata Secretes Indole-3-acetic Acid and Other Biomolecules and Enhances the Biological Attributes of Vigna radiata (L.) R. Wilczek in Water Deficit Conditions.

Abstract: Drought or water stress is a limiting factor that hampers the growth and yield of edible crops. Drought-tolerant plant growth-promoting rhizobacteria (PGPR) can mitigate water stress in crops by synthesizing multiple bioactive molecules. Here, strain PAB19 recovered from rhizospheric soil was biochemically and molecularly characterized, and identified as Enterobacter sp./Leclercia adecarboxylata (MT672579.1). Strain PAB19 tolerated an exceptionally high level of drought (18% PEG-6000) and produced indole-3-acetic acid (176.2 ± 5.6 µg mL−1), ACC deaminase (56.6 ± 5.0 µg mL−1), salicylic acid (42.5 ± 3.0 µg mL−1), 2,3-dihydroxy benzoic acid (DHBA) (44.3 ± 2.3 µg mL−1), exopolysaccharide (204 ± 14.7 µg mL−1), alginate (82.3 ± 6.5 µg mL−1), and solubilized tricalcium phosphate (98.3 ± 3.5 µg mL−1), in the presence of 15% polyethylene glycol. Furthermore, strain PAB19 alleviated water stress and significantly (p ≤ 0.05) improved the overall growth and biochemical attributes of Vigna radiata (L.) R. Wilczek. For instance, at 2% PEG stress, PAB19 inoculation maximally increased germination, root dry biomass, leaf carotenoid content, nodule biomass, leghaemoglobin (LHb) content, leaf water potential (ΨL), membrane stability index (MSI), and pod yield by 10%, 7%, 14%, 38%, 9%, 17%, 11%, and 11%, respectively, over un-inoculated plants. Additionally, PAB19 inoculation reduced two stressor metabolites, proline and malondialdehyde, and antioxidant enzymes (POD, SOD, CAT, and GR) levels in V. radiata foliage in water stress conditions. Following inoculation of strain PAB19 with 15% PEG in soil, stomatal conductance, intercellular CO2 concentration, transpiration rate, water vapor deficit, intrinsic water use efficiency, and photosynthetic rate were significantly improved by 12%, 8%, 42%, 10%, 9% and 16%, respectively. Rhizospheric CFU counts of PAB19 were 2.33 and 2.11 log CFU g−1 after treatment with 15% PEG solution and 8.46 and 6.67 log CFU g−1 for untreated controls at 40 and 80 DAS, respectively. Conclusively, this study suggests the potential of Enterobacter sp./L. adecarboxylata PAB19 to alleviate water stress by improving the biological and biochemical features and of V. radiata under water-deficit conditions.

Fruit Derived Potentially Bioactive Bioengineered Silver Nanoparticles.

Abstract: Introduction Protein-derived biogenic syntheses of inorganic nanoparticles have gained immense attention because of their broad spectrum of applications. Proteins offer a reducing environment to enable the synthesis of nanoparticles and encapsulate synthesized nanoparticles and provide them temporal stability in addition to biocompatibility. Methods In the present study, Benincasa hispida fruit proteins were used to synthesize silver nanoparticles (AgNPs) at 37 °C over five days of incubation. The synthesis of AgNPs was confirmed by UV-Vis spectroscopy, TEM, zeta potential, and DLS analyses. Further, these NPs depicted antibacterial and antibiofilm effects. Additionally, the anticancer activities of nanoparticles were also tested against the lung cancer cell line (A549) with respect to the normal cell line (NRK) using MTT assay. Further, the estimation of ROS generation through DCFH-DA staining along with a reduction in mitochondrial membrane potential by Mito Tracker Red CMX staining was carried out. Moreover, nuclear degradation in the AgNPs treated cells was cross-checked by DAPI staining. Results The average size of AgNPs was detected to be 27 ±1 nm by TEM analysis, whereas surface encapsulation by protein was determined by FTIR spectroscopy. These NPs were effective against bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella enteric, and Staphylococcus epidermis with MICs of 148.12 µg/mL, 165.63 µg/mL, 162.77 µg/mL, and 124.88 µg/mL, respectively. Furthermore, these nanoparticles inhibit the formation of biofilms of E. coli, S. aureus, S. enteric, and S. epidermis by 71.14%, 73.89%, 66.66%, and 64.81%, respectively. Similarly, these nanoparticles were also found to inhibit (IC50 = 57.11 µM) the lung cancer cell line (A549). At the same time, they were non-toxic against NRK cells up to a concentration of 200 µM. Discussion We successfully synthesized potentially potent antibacterial, antibiofilm and anticancer biogenic AgNPs.

Assessment of Chemopreventive Potential of the Plant Extracts against Liver Cancer Using HepG2 Cell Line.

Abstract: The edible parts of the plants Camellia sinensis, Vitis vinifera and Withania somnifera were extensively used in ancient practices such as Ayurveda, owing to their potent biomedical significance. They are very rich in secondary metabolites such as polyphenols, which are very good antioxidants and exhibit anti-carcinogenic properties. This study aims to evaluate the anti-cancerous properties of these plant crude extracts on human liver cancer HepG2 cells. The leaves of Camellia sinensis, Withania somnifera and the seeds of Vitis vinifera were collected and methanolic extracts were prepared. Then, these extracts were subjected to DPPH, α- amylase assays to determine the antioxidant properties. A MTT assay was performed to investigate the viability of the extracts of HepG2 cells, and the mode of cell death was detected by Ao/EtBr staining and flow cytometry with PI Annexin- V FITC dual staining. Then, the protein expression of BAX and BCl2 was studied using fluorescent dye to determine the regulation of the BAX and BCl2 genes. We observed that all the three extracts showed the presence of bioactive compounds such as polyphenols or phytochemicals. The W. somnifera bioactive compounds were found to have the highest anti-proliferative activity on human liver cancer cells.

Exploring the Antibacterial and Antibiofilm Efficacy of Silver Nanoparticles Biosynthesized Using Punica granatum Leaves

Abstract: The current research work illustrates an economical and rapid approach towards the biogenic synthesis of silver nanoparticles using aqueous Punica granatum leaves extract (PGL-AgNPs). The optimization of major parameters involved in the biosynthesis process was done using Box-Behnken Design (BBD). The effects of different independent variables (parameters), namely concentration of AgNO3, temperature and ratio of extract to AgNO3, on response viz. particle size and polydispersity index were analyzed. As a result of experiment designing, 17 reactions were generated, which were further validated experimentally. The statistical and mathematical approaches were employed on these reactions in order to interpret the relationship between the factors and responses. The biosynthesized nanoparticles were initially characterized by UV-vis spectrophotometry followed by physicochemical analysis for determination of particle size, polydispersity index and zeta potential via dynamic light scattering (DLS), SEM and EDX studies. Moreover, the determination of the functional group present in the leaves extract and PGL-AgNPs was done by FTIR. Antibacterial and antibiofilm efficacies of PGL-AgNPs against Gram-positive and Gram-negative bacteria were further determined. The physicochemical studies suggested that PGL-AgNPs were round in shape and of ~37.5 nm in size with uniform distribution. Our studies suggested that PGL-AgNPs exhibit potent antibacterial and antibiofilm properties.

The toxicity analysis of PVP, PVA and PEG surface functionalized ZnO nanoparticles on embryonic as well as adult Danio rerio.

Abstract: Globally, the production of zinc oxide nanoparticles (ZnO NPs) increased due to its wide applications including cosmetics, paints etc., and gets accumulated in the environment during their production, use or end-of-life. The toxic effects of the NPs vary with the presence of various surface modification agents. In the current report, toxic effect of bare and capped ZnO NPs with polymeric surface modifying agent including polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) is studied against adult as well as embryonic zebra fish. The surface capped NPs showed great variation in toxicity levels. It was observed that ZnO-PVA showed highly reduced toxic effects relative to ZnO-PEG and ZnO-PVP. Further, various environmental agents including humic acid can also have an impact on NPs toxicity. ZnO particles showed increased toxic effect in humic acid presence. The uptake of ZnO particles by D. rerio was high in the order of PVP-, PEG- and PVA- followed by bare-ZnO. The current investigation found that ZnO NPs dissolution and uptake are the major factors which cause the toxicity against adult as well as embryonic zebra fishes respectively.

Naphthyridine derived colorimetric and fluorescent turn off sensors for Ni2+ in aqueous media.

Abstract: Highly selective and sensitive 2,7-naphthyridine based colorimetric and fluorescence “Turn Off” chemosensors (L1-L4) for detection of Ni2+ in aqueous media are reported. The receptors (L1-L4) showed a distinct color change from yellow to red by addition of Ni2+ with spectral changes in bands at 535–550 nm. The changes are reversible and pH independent. The detection limits for Ni2+ by (L1-L4) are in the range of 0.2–0.5 µM by UV–Visible data and 0.040–0.47 µM by fluorescence data, which is lower than the permissible value of Ni2+ (1.2 µM) in drinking water defined by EPA. The binding stoichiometries of L1-L4 for Ni2+ were found to be 2:1 through Job’s plot and ESI–MS analysis. Moreover the receptors can be used to quantify Ni2+ in real water samples. Formation of test strips by the dip-stick method increases the practical applicability of the Ni2+ test for “in-the-field” measurements. DFT calculations and AIM analyses supported the experimentally determined 2:1 stoichiometries of complexation. TD-DFT calculations were performed which showed slightly decreased FMO energy gaps due to ligand–metal charge transfer (LMCT).

Morphological and phylogenetic appraisal of Ophioceras (Ophioceraceae, Magnaporthales).

Abstract: Ophioceras is accommodated in the monotypic family Ophioceraceae (Magnaporthales, Sordariomycetes), and the genus is delimited based on molecular data. During an ongoing survey of bambusicolous fungi in southwest China, we collected a submerged decaying branch of bamboo from Sichuan Province, China and an Ophioceras species occurring on this substrate was observed and isolated. An Ophioceras taxon was delimited based on morphological characteristics and combined LSU, RPB1 and ITS sequence analyses and is described as Ophioceras sichuanense sp. nov. The species formed a well-supported clade basal to Ophioceras (100% ML, 1.00 PP). Based on the updated phylogenetic tree of Magnaporthales, Ceratosphaerella castillensis (generic type) and C. rhizomorpha formed a clade within Ophioceras and morphologically resemble Ophioceras. Therefore, Ceratosphaerella is synonymized under Ophioceras. The phylogenetic relationships of Ophioceras are discussed in relation to morphological similarities of genera in Magnaporthales. The generic circumscription of Ophioceras is emended.