Development of clove oil based nanoencapsulated biopesticide employing mesoporous nanosilica synthesized from paddy straw via bioinspired sol-gel route.

Paddy straw (PS) burning is a concerning issue in South Asian countries, clamoring for exploring alternative management strategies. Being a rich source of silica, PS can be a potential nanosilica (SiNPs) source. The current study reports a pioneering approach for green synthesis of high-purity mesoporous SiNPs by sol-gel method using the aqueous extract of Sapindus mukorossi seed pericarp as a stabilizer. The mesoporous nature of SiNPs was harnessed as a carrier for the essential oil to develop the carrier-based formulation. SiNPs were characterized using XRD, EDX, FTIR, FE-SEM, TEM, AFM, DLS, water contact angle, and BET analysis. The synthesized SiNPs possessed a spheroid morphology with an average particle size of 20.34 ± 2.64 nm. XRD results confirmed its amorphous nature. The mesoporous nature of SiNPs was confirmed using BET analysis which showed a cumulative pore volume of 2.059 cm3/g and a high surface area of 746.32 m2/g. The SiNPs were further loaded with clove essential oil (CEO), and the encapsulation of CEO was assessed using UV-Vis, FTIR, and BET analysis. The in-vitro antifungal activity of CEO and CEO-loaded SiNPs (CEO-SiNPs) was evaluated using the agar plate assay. UV-Vis results depicted 62.64% encapsulation of CEO in SiNPs. The antifungal efficacy of CEO-SiNPs against F. oxysporum exhibited minimum inhibitory concentration (MIC), i.e., 125 mg/L, while the MIC of CEO was found to be 250 mg/L. The study delivers new insights into the holistic utilization of PS and propitious contribution toward the circular economy and Sustainable Development Goals (SDGs).

In vitro and computational studies of the ß-lactamase inhibition and ß-lactam potentiating properties of plant secondary metabolites.

ß-lactam resistance in bacteria is primarily mediated through the production of ß-lactamases. Among the several strategies explored to mitigate the issue of ß-lactam resistance, the use of plant secondary metabolites in combination with existing ß-lactams seem promising. The present study aims to identify possible ß-lactam potentiating plant secondary metabolites following in vitro and in silico approaches. Among 180 extracts from selected 30 medicinal plants, acetone extract of Ficus religiosa (FRAE) bark recorded the least IC50 value of 3.9 mg/ml. Under in vitro conditions, FRAE potentiated the activity of ampicillin, which was evidenced by the significant reduction in IC50 values of ampicillin against multidrug resistant bacteria. Metabolic profiling following HR-LCMS analysis revealed the presence of diverse metabolites viz. flavonoids, alkaloids, terpenoids, etc. in FRAE. Further, ensemble docking of the FRAE metabolites against four Class A ß-lactamase (SHV1, TEM1, KPC2 and CTX-M-27) showed quercetin, taxifolin, myricetin, luteolin, and miquelianin as potential inhibitors with the least average binding energy. In molecular dynamic simulation studies, myricetin formed the most stable complex with SHV1 and KPC-2 while miquelianin with TEM1 and CTX-M-27. Further, all five metabolites interacted with amino acid residue Glu166 in Ω loop of ß-lactamase, interfering with the deacylation step, thereby disrupting the enzyme activity. The pharmacokinetics and ADMET profile indicate their drug-likeness and non-toxic nature, making them ideal ß-lactam potentiators. This study highlights the ability of metabolites present in FRAE to act as ß-lactamase inhibitors.Communicated by Ramaswamy H. Sarma.

Analyzing the potential of selected plant extracts and their structurally diverse secondary metabolites for α-glucosidase inhibitory activity: in vitro and in silico approach.

Inhibiting α-glucosidase activity is a therapeutic method to regulate post-prandial hyperglycemia in humans. Here, in-vitro and in-silico studies were used to find α-glucosidase inhibitory plant secondary metabolites (PSM). Among 408 solvent extracts from 70 plants tested for α-glucosidase inhibition, 174 had IC50 ≤ 3 mg/ml. α-glucosidase inhibitory PSM is found in several plant species and solvent extracts, indicating their diversity. Further, ensemble molecular docking and structural activity relationship analysis supported this hypothesis where the top 100 PSM with the least binding energy (BE) among the 539 PSM belonged to sesquiterpenoids (34%), catechols (11%), flavonoids (9%) and steroidal lactones (8%). Shortlisted 11 PSM were subjected to molecular dynamic simulation. Withanolide J recorded the least BE of -66.424 ± 22.333 kJ/mol, followed by Withacoagulin I (-64.665 ± 24.030 kJ/mol). When different simulation frames were analyzed, PSM of withanolide groups was stabilized in the narrow entrance of the active pocket forming H-bond with LYS156, TYR158, PHE159, PHE303 PRO312, LEU313, ARG315 and PHE134. Similarly, Hydroxytuberosone and 1, 8-Dihydroxy-3-carboxy-9, 10-anthraquinone (DHCA) formed H-bond with ASP307 located on the loop at the entrance of the active pocket. In the case of Neoliquiritin and Kaempferol-3-o-alpha-L-rhamnoside (KALR), glucose moiety interacted with the GLU277 and ASP215 (catalytic amino acid residues) through H-bonds. In addition, these 11 PSM were found to fulfil the criteria of drug-likeness as per Lipinski's rule of five and pharmacokinetic profile. The present study strengthens the library of α-glucosidase inhibitory plants and PSM, providing valuable information for Type-II Diabetes mellitus management.Communicated by Ramaswamy H. Sarma.

Computational and data mining studies to understand the distribution and dynamics of Temoneria (TEM) ß-lactamase and their interaction with ß-lactam and ß-lactamase inhibitors.

ß-lactams are large group of antibiotics widely used to suppress the bacterial growth by inhibiting cell wall synthesis. Bacterial resistance against ß-lactam antibiotics is primarily mediated through the production of Temoneria (TEM) ß-lactamase (BLs), with almost 474 variants identified in Lactamase Engineering Database (LacED). The present study aims to develop a model to track the evolution of TEM BLs and their interactions with ß-lactam and BLs inhibitors through data mining and computational approaches. Further, the model will be used to predict the effective combinations of ß-lactam and BLs inhibitors to treat the bacterial infection harbouring emerging variants of ß-lactamase. The molecular docking study results demonstrated that most TEM mutants recorded the least binding energy to penicillin and cephalosporin (I/II/III/IV/V generations) class of antibiotics. On the contrary, the same mutants recorded higher binding energy to carbapenem and Monobactam class of antibiotics. Among the BLs inhibitors, tazobactam recorded the least binding energy against most of the TEM mutants, indicating that it can lower the catalytic activity of TEM BLs, thereby potentiating antibiotic action. Similarly, data mining work has assisted us in creating a database of TEM mutants that has comprehensive data on mutations, bacterial diversity, Km, MIC, and IRT types. It has been noted that earlier released antibiotics like amoxicillin and ampicillin had lower Km and higher MIC values, which indicates the prevalence of bacterial resistance. By analysing the differential binding energy (ΔBE) of the selected TEM mutants against ß-lactam and BLs inhibitors, the most effective combination of ß-lactam (carbapenem and monobactam class of antibiotics) and BLs inhibitors (tazobactam) was identified, to cure bacterial diseases/infections and to prevent similar antibiotic resistance outbreaks. Therefore, our study opens a new avenue in developing strategies to manage antibiotic resistance in bacteria.

Unraveling the potential role of bioactive molecules produced by Trichoderma spp. as inhibitors of tomatinase enzyme having an important role in wilting disease: an in-silico approach.

Tomatinase; a saponin detoxification enzyme produced by Fusarium oxysporumf.sp. lycopersici is reported as a causative agent for wilting disease in tomato crops. The disease is instigated by inhibiting the activity of α-tomatine. Trichoderma spp. widely used as biocontrol agent play an essential role in plant growth and pathogen control. In the current study, an in-silico approach using substrate docking, molecular dynamics and MM/PBSA analysis was used to evaluate the potential role of bioactive metabolites produced by Trichoderma spp. The study aims to establish the efficacy of catalytic tendency of the bioactive metabolites to combat the effect of tomatinase enzyme employing α-tomatine as the substrate. By means of the integrated molecular modeling approach; novel bioactive metabolites namely, Trichodermamide B, Trichosetin and Virone were found to be the potential inhibitors against tomatinase enzyme secreted by Fusarium oxysporum f.sp. lycopersici. Molecular dynamic (MD) simulations displayed that the screened ligands bound tomatinase during 150 ns of MD simulations. Furthermore, the (MM-PBSA) free energy calculations depicted that screened molecules possess stable and favorable energies for Trichodermamide B (-7.1 kcal/mol), Trichosetin (-7.4 kcal/mol) and Virone (-7.9 kcal/mol) thereby instigating robust binding with the enzyme's binding site. The results attained in this study, reflects that these bioactive metabolites may serve as potential substrates to control and inhibit the tomatinase enzyme; playing an integral role in combating the wilt disease.Communicated by Ramaswamy H. Sarma.

Co-occurrence of functionally diverse bacterial community as biofilm on the root surface of Eichhornia crassipes (Mart.) Solms-Laub.

The current study investigates the functional diversity of bacterial community existing as a biofilm on the root surface of water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.) grown in Yamuna river, Delhi, India. Forty-nine bacterial isolates recorded a diverse pattern of susceptibility/resistance to 23 antibiotics tested. Most of the bacterial isolates were susceptible to Ofloxacin, Ciprofloxacin, Ceftriaxone, Gentamicin, and Cefepime and resistant to Ceftazidime, Nitrofurantoin, Ampicillin, and Nalidixic acid. Isolate RB33-V recorded resistant against 11 antibiotics tested, and RB42-V was found susceptible to most of the antibiotics tested. Among the seven heavy metals tested, the highest of 39 bacteria showed resistance to zinc, and least of 9 bacteria recorded resistance against cadmium. Isolate RB20-III was susceptible to all heavy metals tested, and RB23-III was found resistance for six heavy metals tested. A higher correlation was observed with zinc and multiple antibiotic resistance, and Ceftazidime resistance was most frequently associated with all the heavy metals tested. These bacteria grow optimally under neutral-alkali conditions and susceptible to acidic conditions, and they can withstand a broad range of temperatures and salt concentrations. They are very poor in phosphate solubilization. Further, the bacteria recorded varied results for beneficial traits, hemolytic, and DNase activity. The results of bacterial characterization indicated that this bacterial community is of multi-origin in nature and are assisting the host-plant in withstanding the adverse and fluctuating conditions of the Yamuna river by reducing the toxic effect of heavy metals, antibiotics and other xenobiotics.

Efficient and prolonged antibacterial activity from porous PLGA microparticles and their application in food preservation.

Simple addition of a minute quantity of non-toxic mustard oil in water/oil/water (W/O/W) double emulsion led to a porous morphology at the surface as well as in the interior of the biodegradable PLGA (Poly(l-lactide-co-glycolide)) microparticles. An attempt was made to understand the mechanism of pore formation by analyzing optical micrographs and SEM images in addition to solution viscosity of organic phase and interfacial tension values between organic and aqueous phases. The origin of surface porosity was thought to come from the inclusion of inner water droplet, stabilized by heteroaggregation of mustard oil and PLGA chains along with PVA (polyvinyl alcohol), to the solidifying polymer skin. The surface pores did not arise in absence of mustard oil. The encapsulation and release of antibacterial active (benzoic acid) from porous PLGA particles was studied in PBS buffer (pH 7) at 37 °C for 60 days. The release profiles were well-controlled in nature, and found to be influenced by surface porosity of the particles that can be manipulated by varying the amount of mustard oil. The release mechanism can well be explained with the help of power law model. Strikingly, in liquid medium, porous particles were found completely suppressing the growth of Escherichia coli and Staphylococcus aureus for a prolonged period of 60 days. The strong antimicrobial activity (100% inhibition of bacterial growth) in porous particles can be linked to the enhanced surface area due to the formation of micro/nano pores which accelerate the hydrolytic degradation of PLGA to release lactic acid/glycolic acid (antibacterial) in addition to encapsulated antibacterial (benzoic acid). In a food model system, the shelf life of the water melon juice was also found to be enhanced by suppressing the growth of the natural microbes in comparison to control.

Differential expression of structural and functional proteins during bean common mosaic virus-host plant interaction.

Bean common mosaic virus (BCMV), the most common seed-borne pathogen in Phaseolus vulgaris L. is known to cause severe loss in productivity across the globe. In the present study, proteomic analyses were performed for leaf samples from control (healthy) and susceptible BCMV infected plants. The differential expression of proteins was evaluated using two-dimensional gel electrophoresis (2-DE). Approximately, 1098 proteins were spotted, amongst which 107 proteins were observed to be statistically significant with differential expression. The functional categorization of the differential proteins illustrated that they were involved in biotic/abiotic stress (18%), energy and carbon metabolism (11%), photosynthesis (46%), protein biosynthesis (10%), chaperoning (5%), chlorophyll (5%) and polyunsaturated fatty acid biosynthesis (5%). This is the first report on the comparative proteome study of compatible plant-BCMV interactions in P. vulgaris which contributes largely to the understanding of protein-mediated disease resistance/susceptible mechanisms.

1-Aminocyclopropane-1-carboxylic acid deaminase producing beneficial rhizobacteria ameliorate the biomass characters of Panicum maximum Jacq. by mitigating drought and salt stress.

1-Aminocyclopropane-1-carboxylic acid (ACC) is a precursor molecule of ethylene whose concentration is elevated in the plant subjected to biotic and abiotic stress. Several soil microorganisms are reported to produce ACC deaminase (ACCd) which degrades ACC thereby reducing stress ethylene in host plants. This study is aimed to apply ACCd producing beneficial rhizobacteria to improve biochemical parameters and cell wall properties of Panicum maximum exposed to salt and drought stress, focusing on bioethanol production. Thirty-seven ACCd producing bacteria isolated from rhizospheric soil of field grown P. maximum and 13 were shortlisted based on their beneficial traits (root colonization, production of indole acetic acid, siderophore, hydrogen cyanide, phosphate solubilization, biofilm formation, tolerance to salt and Polyethylene glycol) and a total score obtained. All shortlisted bacteria were found significant in enhancing the plant growth, water conservation, membrane stability, biocompatible solutes and protein, phenolic contents and photosynthetic pigments in plants grown under stress conditions. Cell wall composition (Cellulose, Hemicellulose and Lignin) of the treated plants grown under stress conditions recorded a significant improvement over their respective controls and found equivalent to the plants grown under normal circumstances. Biomass from bacterial treatment recorded higher total reducing sugars upon pre-treatment and hydrolysis, and theoretical bioethanol yield.