Synthesis and characterization of chitosan/zinc oxide nanocomposite for antibacterial activity onto cotton fabrics and dye degradation applications.

The present study reports an eco-friendly synthesis of chitosan/zinc oxide (CS/ZnO) nanocomposite using S. lycopersicum leaf extract by a bio-inspired method. The synthesized CS/ZnO nanocomposite was characterized by using UV-visible spectroscopy, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), fourier transform infrared spectroscopy (FTIR) techniques. The XRD analysis revealed wurtzite crystalline structure of CS/ZnO nanocomposite. Electron microscopy images showed agglomeration of CS/ZnO nanocomposite having spherical shaped structure with an average size of 21-47 nm. The observed bands around 400-500 cm-1 in the IR spectrum indicated the presence of metal­oxygen bond, whereas bands at 1512 and 1745 cm-1 indicated the presence of amine groups (-NH2) which confirms the presence of CS in the CS/ZnO nanocomposite. The synthesized nanocomposite showed potential antibacterial activity against skin infection causing S. aureus and the mechanism of bactericidal activity was confirmed by using FE-SEM. The CS/ZnO nanocomposite incorporated cotton fabrics also exhibited antibacterial activity against S. aureus, B. subtilis and E. coli. Furthermore, CS/ZnO nanocomposite acted as photocatalyst for the degradation of Congo red under sunlight irradiation. In conclusion, as-synthesized CS/ZnO nanocomposite can be used as bactericidal agent in textile industries and also as photocatalyst for dye degradation.

Marker Assisted Gene Pyramiding (MAGP) for bacterial blight and blast resistance into mega rice variety "Tellahamsa".

Bacterial blight (BB) and fungal blast diseases are the major biotic constraints that limit rice productivity. To sustain yield improvement in rice, it is necessary to developed yield potential of the rice varieties by incorporation of biotic stress resistance genes. Tellahamsa is a well-adapted popular high yielding rice variety in Telangana state, India. However, the variety is highly susceptible to BB and blast. In this study, simultaneous stepwise transfer of genes through marker-assisted backcross breeding (MABB) strategy was used to introgress two major BB (Xa21 and xa13) and two major blast resistance genes (Pi54 and Pi1) into Tellahamsa. In each generation (from F1 to ICF3) foreground selection was done using gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13), Pi54MAS (Pi54) and RM224 (Pi1). Two independent BC2F1 lines of Tellahamsa/ISM (Cross-I) and Tellahamsa/NLR145 (Cross-II) possessing 92% and 94% recurrent parent genome (RPG) respectively were intercrossed to develop ICF1-ICF3 generations. These gene pyramided lines were evaluated for key agro-morphological traits, quality, and resistance against blast at three different hotspot locations as well as BB at two locations. Two ICF3 gene pyramided lines viz., TH-625-159 and TH-625-491 possessing four genes exhibited a high level of resistance to BB and blast. In the future, these improved Tellahamsa lines could be developed as mega varieties for different agro-climatic zones and also as potential donors for different pre-breeding rice research.

Corrigendum to "Studies on solvent precipitation of levan synthesized using Bacillus subtilis MTCC 441" [Heliyon 5 (9) (September 2019) e02414].

[This corrects the article DOI: 10.1016/j.heliyon.2019.e02414.].

Effect of temperature on Pi54-mediated leaf blast resistance in rice.

Assessment of temperature effect on plant resistance against diseases has become essential under climate change scenario as temperature rise is anticipated to modify host resistance. To determine temperature influence on resistance gene, a pair of near-isogenic rice lines differing for the Pi54 resistance gene was assessed against leaf blast. Blast resistance was determined as the extent of infection efficiency (IE) and sporulation (SP) at suboptimal (22 °C and 32 °C) and optimal temperature (27 °C) of pathogen aggressiveness. Relative resistance for IE and SP was higher at suboptimal temperature as compared to that of optimal temperature. Maximum level of resistance was at 22 °C where higher levels of expression of Pi54 and defence-regulatory transcription factor WRKY45 were also noted. At 32 °C, although some level of resistance noted, but level of Pi54 and WRKY45 expression was too low, suggesting that resistance recorded at higher temperature was due to reduced pathogen aggressiveness. At the optimal temperature for pathogen aggressiveness, comparatively lower levels of Pi54 and WRKY45 expression suggest possible temperature-induced interruption of the defence processes. The variation in resistance patterns modulated by temperature is appeared to be due to pathogen's sensitivity to temperature that leads to varying levels of Pi54 gene activation. Quick and violent activity of the pathogen at optimal temperature came into sight for the interruption of defence process activated by Pi54 gene. Evaluation of blast resistance genes under variable temperature conditions together with weather data could be applied in screening rice genotypes for selection of resistance having resilience to temperature rise.

Bio-inspired synthesis of chitosan/copper oxide nanocomposite using rutin and their anti-proliferative activity in human lung cancer cells.

Polymer functionalized metal oxide nanocomposites are great interest due to wide range of application, especially in nanomedicine. The present study reports an eco-friendly bio-inspired synthesis of chitosan/copper oxide (CS-CuO) nanocomposite for the first time using rutin. The bio-synthesized CS-CuO nanocomposite was characterized using UV-Visible spectroscopy, FE-SEM, EDS, TEM, XRD and FTIR analyses. FE-SEM and TEM images revealed the synthesized CS-CuO nanocomposite having spherical shaped structure with an average size of 10-30 nm. EDS analysis confirmed the elements present in synthesized CS-CuO nanocomposite. FTIR studies revealed the role of rutin and chitosan for reduction, capping and synthesis of CS-CuO nanocomposite from the precursor copper salt. The XRD analysis revealed monoclinic structure of CS-CuO nanocomposite. Anti-proliferative activity of the CS-CuO nanocomposite was evaluated in human lung cancer cell line A549. Synthesized CS-CuO nanocomposite showed concentration-depended anti-proliferative activity against A549 cancer cells and their IC50 value was found to be 20 ±â€¯0.50 µg/mL. Furthermore, synthesized nanocomposite induce apoptosis in treated A549 cancer cells assayed by AO/EtBr fluorescent staining method. In conclusion, the synthesized CS-CuO nanocomposite using rutin can be used as a potential anticancer agent in biomedical and clinical sectors.

Synthesis and characterization of chitosan/iron oxide nanocomposite for biomedical applications.

The structural and optical properties of metal oxide nanoparticles exhibit remarkable changes when coated with organic polymers. In this work, we report the preparation of chitosan (CS) coated iron oxide nanocomposite using rutin by a facile greener route. The formation of iron oxide nanoparticles (FeO NPs) and CS coated iron oxide nanocomposite (CS-FeO) were preliminarily confirmed by color change and UV-Visible spectroscopy. FE-SEM images of FeO NPs revealed rod shaped agglomerated particles whereas CS-FeO nanocomposite showed rod shaped agglomerated small grains. TEM analysis revealed that the size of the nanoparticles varies from 20 to 90 nm. The observed bands at 500-800 cm-1 in the FTIR spectrum indicated the presence of metal­oxygen (FeO) bond, whereas band at 1646 cm-1 indicated the presence of amino groups (-NH2) which confirms the CS in the prepared CS-FeO nanocomposite. The prepared nanoparticles showed potential antibacterial activity against both Gram-positive and Gram-negative bacterial pathogens. The antioxidant activity of FeO NPs and CS-FeO nanocomposite was evaluated by DPPH and H2O2 assays. The percentage of antioxidant activity was increased with increasing concentration of FeO NPs and CS-FeO nanocomposite. CS-FeO nanocomposite exhibiting potentially better biomedical property than the uncoated FeO NPs indicates that CS-FeO nanocomposite is a promising bio-nanomaterial for many biological applications.

Preparation of chitosan coated zinc oxide nanocomposite for enhanced antibacterial and photocatalytic activity: As a bionanocomposite.

The surface coating of metal oxide nanoparticles using biopolymer chitosan has evolved to become an important area of polymer nanotechnology. Herein, we report the preparation of chitosan coated zinc oxide (CS-ZnO) nanocomposite for the first time by a green chemistry approach using bioflavonoid rutin. The formation of CS-ZnO nanocomposite was preliminarily confirmed by color change and UV-Visible spectroscopy. FE-SEM images revealed agglomeration of CS-ZnO nanocomposite having predominant rod shaped structure. The surface coating of chitosan polymer on ZnO was confirmed by XRD, EDS, FTIR, DLS and zeta potential analysis. The prepared CS-ZnO nanocomposite showed significant antibacterial activity against both Gram-positive and Gram-negative bacterial pathogens. However, the prepared nanocomposite was more effective against Gram-negative bacteria compared to Gram-positive bacteria. The highest zone of inhibition by CS-ZnO nanocomposite was reported against E. coli (25.5 mm) followed by K. pneumoniae (24.5 mm), S. aureus (22.5 mm) and least against B. subtilis (21 mm). Furthermore, the prepared nanocomposite acted as photocatalyst for the degradation of Methylene blue and Congo red under sunlight irradiation.

Synthesis, characterization and antibacterial activity of hybrid chitosan-cerium oxide nanoparticles: As a bionanomaterials.

The hybrid chitosan cerium oxide nanoparticles were prepared for the first time by green chemistry approach using plant leaf extract. The intense peak observed around 292nm in the UV-vis spectrum indicate the formation of cerium oxide nanoparticles. The XRD pattern revealed that the hybrid chitosan-cerium oxide nanoparticles have a polycrystalline structure with cubic fluorite phase. The FTIR spectrum of prepared samples showed the formation of Ce-O bonds and chitosan main chains COC and CO. The FESEM image of hybrid chitosan cerium oxide nanoparticles revealed that the particles are spherical in shape with grains size varying from 23.12nm to 89.91nm. EDAX analysis confirmed the presence of Ce, O, C and N elements in the prepared sample. TEM images showed that the prepared hybrid chitosan-cerium oxide nanoparticles are predominantly uniform in size and most of the particles are spherical in shape with less agglomeration and the particles size varies from 3.61nm to 24.40nm. The prepared chitosan cerium oxide nanoparticles of 50µL concentration showed good antibacterial properties against test pathogens, which was confirmed by the FESEM analysis. The prepared small particle size facilitate that these hybrid ChiCO2 NPs could effectively be used in biomedical applications.

Protein-protein and DNA-protein interactions mediate induction of defense genes by fruit extract of Azadirachta indica A. Juss. in Solanum lycopersicum L.

KEY MESSAGE: The present work demonstrates that induction of defense-related genes in tomato by neem extract was mediated by protein-protein and DNA-protein interactions. The induction of elicitor-mediated defense responses in plants is known, but the molecular mechanisms underlying its induction are not well studied. In the present study, third node leaf from the base of aseptically raised tomato plants was treated with aqueous fruit extracts of Azadirachta indica A. Juss. (neem). Samples were collected from the treated node at 24-h intervals for up to 96 h and analyzed for the gene expression of phenylalanine ammonia lyase (PAL), Peroxidase (POX) and Polyphenol Oxidase (PPO), ß-actin (standard). Samples were collected from elicitor-induced node at 5-min interval up to 70 min for analysis of protein-protein and DNA-protein interactions. The results demonstrated the induction of expression of PAL, POX and PPO due to the treatment whereas no change was observed in the expression of ß-actin. There was disappearance of lower molecular weight proteins which cross-linked with other proteins to form complexes. MALDI-TOF MS analysis revealed the interaction of mitogen-activated protein kinases (MAPK). The analysis of proteins interacted with DNA after induction by neem extract indicated the involvement of WRKY transcriptional factors. Neem-elicited defense responses could possibly due to interaction of proteins with other proteins and transcription factors with DNA which might be crucial in enhancing the expression of defense-related genes (PAL, POX and PPO).

Isolation of anticancer drug TAXOL from Pestalotiopsis breviseta with apoptosis and B-Cell lymphoma protein docking studies.

BACKGROUND: Extraction and investigation of TAXOL from Pestalotiopsis breviseta (Sacc.) using protein docking, which is a computational technique that samples conformations of small molecules in protein-binding sites. Scoring functions are used to assess which of these conformations best complements the protein binding site and active site prediction. MATERIALS AND METHODS: Coelomycetous fungi P. breviseta (Sacc.) Steyaert was screened for the production of TAXOL, an anticancer drug. RESULTS: TAXOL PRODUCTION WAS CONFIRMED BY THE FOLLOWING METHODS: Ultraviolet (UV) spectroscopic analysis, Infrared analysis, High performance liquid chromatography analysis (HPLC), and Liquid chromatography mass spectrum (LC-MASS). TAXOL produced by the fungi was compared with authentic TAXOL, and protein docking studies were performed. CONCLUSION: The BCL2 protein of human origin showed a higher affinity toward the compound paclitaxel. It has the binding energy value of -13.0061 (KJ/Mol) with four hydrogen bonds.

Effect on gallbladder function subsequent to truncal vagotomy and gastrojejunostomy for chronic duodenal ulcer.

The effect of truncal vagotomy on gallbladder function and on the incidence of lithogenesis has remained controversial. A prospective and retrospective investigational study was undertaken to evaluate the effect of truncal vagotomy and gastrojejunostomy on gallbladder function. The study included a total of 76 patients and 77 controls. In Group I (Prospective group), 32 consecutive patients with chronic duodenal ulcer and gastric outlet obstruction undergoing truncal vagotomy and gastrojejunostomy were included. Group II included 25 age and gender matched controls (prospective group). Group III included 44 patients who had undergone truncal vagotomy and gastrojejunostomy 3 years or more prior to presentation (Retrospective group) and Group IV included 52 age and gender matched controls for the retrospective group. The patients in the prospective groups were followed up for a period of 1 year. An alkaline tide test was done in the prospective and retrospective group to assess for the completeness of vagotomy. Gallbladder contractile response to fatty meal and the presence of stones and sludge were noted in all the four groups by ultrasonography. There were 30 patients in the prospective group and 40 in the retrospective group after excluding patients with incomplete vagotomy. On ultrasound examination, there was no significant difference in the gallbladder volume and contractility of the study group when compared with the controls. Gallbladder sludge was found in 16 to 25% of patients in the prospective group (group I) during follow up, where as similar finding was documented in 8% of the matched control (group II (P>0.1). However, in the retrospective (group III) 10% (4 out of 40) had calculi and 20% of patients demonstrated sludge which was significantly higher when compared with the controls (p = 0.001). Truncal vagotomy and gastrojejunostomy did not affect gallbladder contractility, but it might predispose to the formation of sludge and subsequent calculi in a proportion of patients in long term.