The present study is focused on the extracellular synthesis of silver nanoparticles (AgNPs) using culture supernatant of an agriculturally important bacterium, Serratia sp. BHU-S4 and demonstrates ...its effective application for the management of spot blotch disease in wheat. The biosynthesis of AgNPs by Serratia sp. BHU-S4 (denoted as bsAgNPs) was monitored by UV-visible spectrum that showed the surface plasmon resonance (SPR) peak at 410 nm, an important characteristic of AgNPs. Furthermore, the structural, morphological, elemental, functional and thermal characterization of bsAgNPs was carried out using the X-ray diffraction (XRD), electron and atomic microscopies, energy dispersive X-ray (EDAX) spectrometer, FTIR spectroscopy and thermogravimetric analyzer (TGA), respectively. The bsAgNPs were spherical in shape with size range of ∼10 to 20 nm. The XRD and EDAX analysis confirmed successful biosynthesis and crystalline nature of AgNPs. The bsAgNPs exhibited strong antifungal activity against Bipolaris sorokiniana, the spot blotch pathogen of wheat. Interestingly, 2, 4 and 10 µg/ml concentrations of bsAgNPs accounted for complete inhibition of conidial germination, whereas in the absence of bsAgNPs, conidial germination was 100%. A detached leaf bioassay revealed prominent conidial germination on wheat leaves infected with B. sorokiniana conidial suspension alone, while the germination of conidia was totally inhibited when the leaves were treated with bsAgNPs. The results were further authenticated under green house conditions, where application of bsAgNPs significantly reduced B. sorokiniana infection in wheat plants. Histochemical staining revealed a significant role of bsAgNPs treatment in inducing lignin deposition in vascular bundles. In summary, our findings represent the efficient application of bsAgNPs in plant disease management, indicating the exciting possibilities of nanofungicide employing agriculturally important bacteria.
The aqueous extract of leaf (LE), fruit (FE) and seed (SE) of Moringa oleifera was assessed to examine the ability to inhibit the oxidative DNA damage, antioxidant and anti-quorum sensing (QS) ...potentials. It was found that these extracts could significantly inhibit the OH-dependent damage of pUC18 plasmid DNA and also inhibit synergistically with trolox, with an activity sequence of LE>FE>SE. HPLC and MS/MS analysis was carried out, which showed the presence of gallic acid, chlorogenic acid, ellagic acid, ferulic acid, kaempferol, quercetin and vanillin. The LE was with comparatively higher total phenolics content (105.04mg gallic acid equivalents (GAE)/g), total flavonoids content (31.28mg quercetin equivalents (QE)/g), and ascorbic acid content (106.95mg/100g) and showed better antioxidant activity (85.77%), anti-radical power (74.3), reducing power (1.1 ascorbic acid equivalents (ASE)/ml), inhibition of lipid peroxidation, protein oxidation, OH-induced deoxyribose degradation, and scavenging power of superoxide anion and nitric oxide radicals than did the FE, SE and standard α-tocopherol. Eventually, LE and FE were found to inhibit violacein production, a QS-regulated behavior in Chromobacterium violaceum 12472.
In order to determine antioxidant activity, the five extracts/fractions of red onion peel were studied for their total content of phenolics (TPC), flavonoids (TFC), antioxidant activity (AOA), free ...radical scavenging activity (FRSA), assayed by DPPH radical in the terms of anti-radical power (ARP) and reducing power (RP), expressed as ascorbic acid equivalents (ASE)/ml. High TPC (384.7±5.0mg GAE/g), TFC (165.2±3.2mg QE/g), AOA (97.4±7.6%), ARP (75.3±4.5) and RP (1.6±0.3 ASE/ml) were found for the ethyl acetate (EA) fraction. EA fraction had markedly higher antioxidant capacity than butylated hydroxytoluene (BHT) in preventive or scavenging capacities against FeCl3-induced lipid peroxidation, protein fragmentation, hydroxyl (site-specific and non-site-specific), superoxide anion and nitric oxide radicals. EA fraction also showed dose dependent antimutagenic activity by following the inhibition of tobacco-induced mutagenicity in Salmonella typhimurium strains (TA102) and hydroxyl radical-induced nicking in plasmid pUC18 DNA. HPLC and MS/MS analysis showed the presence of ferulic, gallic, protocatechuic acids, quercetin and kaempferol. The large amount of polyphenols contained in EA fraction may cause its strong antioxidant and antimutagenic properties. This information shows that EA fraction of red onion peel can be used as natural antioxidant in nutraceutical preparations.
The beneficial use of silver nanoparticles (AgNPs) in agroecosystems is not fully explored with partial information available, of which most of the studies are limited to laboratory conditions and ...only few involve natural ecosystems. AgNPs, being the most popular metallic nanoparticles exhibiting antimicrobial property, are predominantly used for plant disease management. Owing to the ill hazards of chemically synthesized AgNPs, their biosynthesis using environment-friendly biomolecules is gaining noteworthy attention. In addition, considering the advantages of nanoformulations over biopesticides, there is no doubt that biosynthesized AgNP-based biopesticides could revolutionize the agricultural sector in the future. Though enhanced commercial use of AgNPs has generated biosafety issues in modern scenario but expecting their significant contribution towards agricultural sector, it is too early to predict the risk factor associated with their usage. To unveil the toxicity factor of AgNPs, we need to focus and understand the major interactions of AgNPs in agroecosytems. Hence, the present review highlights (i) the potential application of AgNPs in the agricultural sector particularly for plant disease management, (ii) significance of biosynthesized AgNPs using microbes and plants over their chemical synthesis, (iii) major interactions of AgNPs in agroecosystems (with soil, soil biota, and plants) with emphasis to deal with toxicity-determining factors, and (iv) identifying future research work holding promising applications of biosynthesized AgNPs in agroecosystems.
The gaining attention of underutilized oat crops for both food and feed, mining of quality and yield related genes/QTLs from available germplasms of oat is need of the hour. The large family of ...grasses has a vast number of germplasms that could be harnessed for bio-prospecting. The selection of cross-compatible oat germplasms by molecular markers could be used for the introgression of the novel traits into the elite background of oats. The process needs a thorough study of genetic diversity to see the evolutionary relatedness among germplasms. Considering this, in the present study, the genetic diversity of 38 oat germplasms with 12 agro-morphological traits was carried out using 22 Inter Simple Sequence Repeat (ISSR) markers. We found a high level of polymorphism and 158 distinctive alleles; on average 7.18 alleles per primer, further, high-yielding genotypes were identified with the help of phenotypic data and genetic diversity was analyzed by using DNA fingerprint-based principal component analysis, UPGMA dendrogram. Among these 38 germplasms; eight were identified as superior under high grain yield (OS-424, OS-403, NDO-1101, OL-10, UPO-212, OS-405, OS-6, and OS-346) and another eight germplasms were identified as superior for the high fresh weight (for fodder purpose, NDO-711, RO-19, OL-14, OL-1760/OL-11, NDO-10, UPO-212, UPO-06-1, and RO-11-1). These results suggest that germplasms that are closely related (Cross-compatible) and have good potential for desirable traits could be used for varietal development by using marker-assisted selection.
•Ag/Ge-NW/Si (MS) device was synthesized using the glancing angle deposition (GLAD) technique.•Strong dependence of capacitance and conductance on both frequency and voltage is observed.•The Dit is ...effective in the inversion region at low frequency.•Rs is effective in the accumulation region at high frequency.•The non-ideal behavior of the synthesized MS device is due to Dit and Rs existence.
Catalyst-free Ge-nanowire (NW) was synthesized using the glancing angle deposition (GLAD) technique integrated into an electron beam evaporator. The study is mainly focussed on the analysis of frequency and voltage dependence of the capacitance–voltage (C-V) and conductance-voltage (G/ω-V) characteristics of Ag/Ge-NW/Si device over a wide range of frequency (200 kHz−2 MHz) and voltage (−5 V to +5 V) at room temperature. FEG-SEM image confirmed the successful growth of vertically oriented Ge-NW on Si substrate. Both C-V and G/ω -V values showed wide dispersion in the depletion, inversion, and accumulation region due to interface state density (Dit) and series resistance (Rs). The voltage and frequency-dependent Dit and Rs were calculated from the Hill-Coleman and Nicollian-Brews methods, respectively. It is observed that the overall Dit and Rs for the device decrease with an increase in the frequency at different voltages.
Despite several additive manufacturing techniques are commercially available in market, Fused Deposition Modeling (FDM) is increasingly used by researchers and engineers for new product development. ...FDM is an established process with a plethora of advantages, but the visible surface roughness (SR), being an intrinsic limitation, is major barrier against utilization of fabricated parts for practical applications. In the present study, the chemical finishing method, using vapour of acetone mixed with heated air, is being used. The combined impact of orientation angle, finishing temperature and finishing time has been studied using Taguchi and ANOVA, whereas multi-criteria optimization is performed using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The surface finish was highly responsive to increase in temperature while orientation angle of 0° yielded maximum strength; increase in finishing time led to weight gain of FDM parts. As the temperature increases, the percentage change in surface roughness increases as higher temperature assists the melt down process. On the other hand, anisotropic behaviour plays a major role during tensile testing. The Signal-to-noise (S/N) ratio plots, and ANOVA results indicated that surface finish is directly proportionate to finishing time because a longer exposure results in complete layer reflowing and settlement.
AIMS: To investigate the efficacy of Trichoderma harzianum NBRI‐1055 (denoted as ‘T‐1055’) in suppression of seedling blight of sunflower caused by Rhizoctonia solani Kühn and their impact on host ...defence responses. METHODS AND RESULTS: T‐1055 was applied as seed treatment, soil application and combined application (seed treatment + soil application). Higher protection afforded by combined application of T‐1055 was associated with the marked induction of phenylalanine ammonia‐lyase (PAL), polyphenol oxidase (PPO), peroxidase (PO) and cinnamyl alcohol dehydrogenase (CAD) activities. The activities of PAL and PPO reached maximum at 10 days after sowing (DAS), while PO and CAD levels reached maximum at 12 DAS. This was further supported by the accumulation of total phenolic content that showed an increase up to threefold at 14 DAS. In addition, HPLC analysis revealed that the contents of ferulic and p‐coumaric acids increased by 6·3 and 4·6 times, respectively, at 14 DAS. Amount of gallic acid was also little more than double. Lignin deposition in sunflower root increased by 2·7, 3·4 and 3·7 times through combined application of T‐1055 at 16, 18 and 20 DAS, respectively. Combined application also increased the accumulation of PR‐2 and PR‐3 proteins by 3·3 and 3·9 times, respectively, at 12 DAS in followed by seed treatment alone. CONCLUSIONS: The combined application of T‐1055 triggered defence responses in an enhanced level in sunflower than the soil and seed alone and provided better protection against Rhizoctonia seedling blight. SIGNIFICANCE AND IMPACT OF THE STUDY: Rhizospheric fungal bioagent ‘T‐1055’ can enhance protection in sunflower against the R. solani pathogen through augmented elicitation of host defence responses.
The antioxidant and anti-quorum sensing activities of eight extracts were studied in green pods of
Acacia nilotica. The specific phenolic compositions and their quantifications were performed by HPLC ...and MS/MS, which showed that the HEF (pH 4) was higher in gallic acid, ellagic acid, epicatechin, rutin, and GTs. In order to find antioxidant potential of various extracts, their activities were studied for TPC, AOA, FRSA, RP, inhibition of LPO, FIC activity, HO
and
O
2
-
scavenging activities. Among them HEF (pH 4) has shown potent antioxidant activity. HEF (pH 4) was also found effective in protecting plasmid DNA and HAS protein oxidation induced by HO
. Pre-treatment of HEF (pH 4) at 75 and 150
mg/kg body weight for 6 days caused a significant increase in the levels of CAT and SOD and decrease in the level of MDA content in liver, lungs, kidneys and blood when compared to CCl
4-intoxicated rats. Eventually, the extracts were also screened for anti-QS activity. Of these extracts two showed QS inhibition: HEF (pH 4) and HCE. The results obtained strongly indicate that green pod of
A. nilotica are important source of natural antioxidants.
This minireview explores the environmental bioremediation mediated by genetically engineered (GE) bacteria and it also highlights the limitations and challenges associated with the release of ...engineered bacteria in field conditions. Application of GE bacteria based remediation of various heavy metal pollutants is in the forefront due to eco-friendly and lesser health hazards compared to physico-chemical based strategies, which are less eco-friendly and hazardous to human health. A combination of microbiological and ecological knowledge, biochemical mechanisms and field engineering designs would be an essential element for successful in situ bioremediation of heavy metal contaminated sites using engineered bacteria. Critical research questions pertaining to the development and implementation of GE bacteria for enhanced bioremediation have been identified and poised for possible future research. Genetic engineering of indigenous microflora, well adapted to local environmental conditions, may offer more efficient bioremediation of contaminated sites and making the bioremediation more viable and eco-friendly technology. However, many challenges are to be addressed concerning the release of genetically engineered bacteria in field conditions. There are possible risks associated with the use of GE bacteria in field condition, with particular emphasis on ways in which molecular genetics could contribute to the risk mitigation. Both environmental as well as public health concerns need to be addressed by the molecular biologists. Although bioremediation of heavy metals by using the genetically engineered bacteria has been extensively reviewed in the past also, but the bio-safety assessment and factors of genetic pollution have been never the less ignored.
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