Negative Strains Research Articles

Bacterias resistente a los antibióticos en aguas mineromedicinales “Santagua Chachimbiro”, Ecuador

Bacterial biodiversity in mineral medicinal waters and the antibiotic resistance profiles, is a developing topic in Ecuador. The objective of the work was to know the bacterial microbiota and its resistance profiles to antibiotics of the mineral medicinal waters of the Santagua Chachimbiro spa, located in the Province of Imbabura-Ecuador. 16 water samples were collected. The isolation of the bacterial species was carried out by the membrane filtration technique, using different types of culture media. The identification was carried out according to the schemes proposed by MacFaddin (2003), complemented with the tests of the Microgen galleries. The antibiotic resistance profile was determined by the Kirby and Bauer (1966) plate diffusion method. 85 strains were isolate of which 61% were Gram negative and 39% Gram positive. The main species identified were Aeromonas caviae, Aeromonas eucrenophila, Aeromonas hydrophila, Aeromonas media, Aeromonas salmonicida, Aeromonas schubertii, Bacillus subtilis, Bacillus mycoides, Bacillus spp, Burkholderia cepacia, Citrobacter freundii, Comamonas spp, Pseudomonas aeruginosa, Pseudomonas fluorescenscens, Pseudomonas putida, Pseudomonas stutzeri, Ralstonia pickettii, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdenensis, Staphylococcus saprophyticus, Staphylococcus spp, Staphylococcus warneri and Staphylococcus xylosus. Regarding antimicrobial resistance, most of the Gram negative strains were resistant to penicillin and cephalosporins. Gram positive to oxacillin and penicillin 66,67% were multiresistant to more than three antibiotics. The “Termas de Santagua de Chachimbiro” spa presents a diversity of bacterial species and the presence of environmental resistomes. Keywords: mineral medicinal waters; bacterial biodiversity; resistance to antibiotics; Santagua Chachimbiro Spa

Synthesis of new thiazolyl-thienyl and thiazolyl-thiadiazolyl ketones: Molecular modelling and docking studies as antimicrobial agents

Eight thiazolyl-thienyl and thiazolyl-thiadiazolyl ketones 5a-d and 6a-d were synthesized based on the reaction of 5-(2-bromoacetyl)-4-methyl-2-(methylamino)thiazole (2) and/or N-(4-chlorophenyl)-2-(4-methyl-2-(methylamino)thiazol-5-yl)-2-oxoacetohydrazonoyl bromide (3) with four various thiocarbamoyl compounds 4a-d. The synthesized thiazolyl-thienyl and thiazolyl-thiadiazolyl ketones were optimized using DFT approach offered analogous models in which the thiazolyl, thienyl and thiazolyl nuclei have a planar structure. The HOMO and LUMO of studied hybrids have been consisted mainly of the π- and π*-orbitals of the whole molecule, respectively. Hence, the thiazolyl-thiadiazolyl ketones revealed smaller energy gap (ΔEH-L) than the thiazolyl-thienyl derivatives and may be sorted as 5c < 6c < 6a ≈ 6d < 6b < 5a < 5b < 5d. The antimicrobial activity of synthesized ketones 5 and 6 was examined against representative Gram’s positive and negative bacterial strains along with fungal strains. The amide-thiazolyl thienyl 5d and the nitrile-thiazolyl thiadiazolyl 6a ketones displayed the highest activity against S. aureus and S. pneumoniae, respectively. Conversely, the nitrile-thiazolyl thienyl ketone 5a demonstrated good efficiency against A. fumigatus. Moreover, in-silico molecular docking stimulation was applied to discover the metabolic effectiveness associated to methicillin resistance through the methicillin-resistant strain of Staphylococcus over (PDB:3VSL).

Phytochemical Screening and in vitro Antibacterial Activity of Kyllinga nemoralis Aqueous and Methanolic Root Extracts

The present study focused to explore the phytochemical composition and in vitro antibacterial potential of Kyllinga nemoralis aqueous and methanolic root extracts. The antibacterial activities of K. nemoralis aqueous and methanolic root extracts were tested against five Gram positive and four Gram negative bacteria strains. Disk diffusion method was performed to evaluate antibacterial activities of the both extracts. K. nemoralis aqueous and methanolic root extracts showed a potent antibacterial activity against Gram positive and Gram negative bacteria strains. The methanolic root extract of K. nemoralis showed efficiency against S. aureus, MRSA, S. pyogenes, S. sonnei, E. coli and K. pneumoniae while the aqueous extract of K. nemoralis was found to possess antibacterial activity against S. aureus and MRSA. This activity seems to be related to the phytochemicals (saponins) detected into the aqueous extract and phytochemicals (terpenoid and steroid) in methanolic extract. The results confirm that root extracts of K. nemoralis can be used as a drug to fight infections caused by the broad-spectrum bacteria strains.&#x0D; Keywords&#x0D; Kyllinga nemoralis, Phytochemical Analysis, Disk diffusion, Antibacterial Activity, Minimum Inhibitory Concentration.

Exploring Biodiversity: Sampling, Analysis, and Identification of Microbial Treasures in Diverse Soil Ecosystems

In the present study, bacterial colonies in Cashew Oil Industry Soil (COS), Fertilizer-applied Field Soil (FFS) and Control samples were enumerated and characterized across varying dilution factors. The results revealed significant variations in bacterial colony formation across dilution factors, indicating diverse growth rates and population densities. The investigation aimed to discern the microbial populations and characteristics in these contrasting samples. COS and FFS exhibited dilution-dependent colony counts, showcasing distinctions in bacterial populations compared to Control samples. Morphological analysis revealed diverse colony sizes, shapes, and colours, ranging from small to medium, with hues spanning yellow to orange. Margins, elevations, and opacities varied, and Gram staining indicated both positive and negative strains and Gram-positive cocci and diplococci, were identified illustrating taxonomic diversity. Biochemical tests unveiled diverse metabolic traits, identifying Cellobiosococcus sp. and Staphylococcus sp. at the genus level in COS and Micrococcus sp. in FFS. Given that these three bacterial strains were isolated from contaminated soil and considering the prior use of Micrococcus sp. and Staphylococcus sp. in remediation efforts, our upcoming research will specifically concentrate on exploring the bioremediation potential of pollutants using Micrococcus sp., Cellobiosococcus sp., and Staphylococcus sp., with particular emphasis on the unique capabilities of Cellobiosococcus sp as there are nostudies related to Cellobiosococcus sp. involved in bioremediation.

Optimizations of exopolysaccharide production by Fusariumnygamai strain AJTYC1 and its potential applications as an antioxidant, antimicrobial, anticancer, and emulsifier

BackgroundExopolysaccharides (EPSs) produced by microbes are recognized as biomacromolecules of great significance. EPSs from fungi are widely used in a variety of biotechnological fields, including medicine, bioremediation, and agriculture.ResultsIn this study, ten fungal isolates were isolated from Kafir El-Dair, Qalubia Governorate, Egypt. Isolate 5 produced more exopolysaccharides than the other examined fungi. According to microscopic morphological traits and genetic confirmation by the 18S rRNA gene, isolate 5 was identified as Fusarium nygamai strain AJTYC1. The present study showed that Czapek’s broth media, which contains 6 g/100 ml of sucrose, 10 g/100 ml of peptone, pH 6, and 1.8 × 105 CFU/ml of inoculum size and is incubated at 30 °C for 9 days, was suitable for the production of EPSs from Fusarium nygamai strain AJTYC1 by using static conditions. Fourier transform infrared (FT-IR) was employed in the characterization of EPSs, which exhibited the presence of carboxyl groups, hydroxyl groups, carbonyl groups, and glycosidic bonds. High-performance liquid chromatography (HPLC) detected that EPSs consist of sucrose and glucose. The scavenging activity indicates that EPSs have good antioxidant activity. The partially purified exopolysaccharides produced from F. nygamai strain AJTYC1 exhibited excellent antioxidant and antimicrobial activity against gram positive, gram negative and fungal strains. The EPSs at a dose of 1000 µg/ml exhibited anticancer activity against colorectal colon cancer (HCT116), breast cancer (MCF7), and hepatocellular cancer cell lines. Moreover, EPSs is an effective emulsifier of a variety of vegetable oils, and the emulsion it produces is generally stable for up to 168 h.ConclusionsThe production of EPSs from F. nygamai strain AJTYC1 can be used as antioxidants, antimicrobials, anticancer, and emulsifiers.

Differential expression of urease genes and ureolytic activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa isolates in different nutritional conditions.

Uropathogens have adaptation strategies to survive in the host urinary tract by efficiently utilizing and tolerating the urinary metabolites. Many uropathogens harbour the enzyme urease for the breakdown of urea and the enzymatic breakdown of urea increases the pH and facilitate the struvite crystallization. In this study, the differential urease activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa strains was investigated under different nutritional conditions. The experiments included measurement of growth, pH, urease activity, NH4-N generation and urease gene (ureC) expression among the bacterial strains under different conditions. Further, the implications of urea breakdown on the struvite crystallization in vitro and biofilm formation were also assessed. The study included urease positive isolates and for comparison urease negative isolates were included. Compared to the urease negative strains the urease positive strains formed higher biofilms and motility. The urease positive P. aeruginosa showed significantly higher (p < 0.01) pH and urease activity (A557-A630) compared to E. coli under experimental conditions. Further, supplementation of glucose to the growth media significantly increased the urease activity in P. aeruginosa and in contrast, it was significantly lower in E. coli. The expression profile of urease gene (ureC) was significantly higher (p < 0.001) in P. aeruginosa compared to E. coli and was consistent with the biochemical results of the urease activity under the nutritional conditions. The differential urease activity under two nutritional conditions influenced the biogenic struvite crystallization. It correlated with the urease activity showing higher crystallization rate in P. aeruginosa compared to E. coli. The results highlight the differential urease activity in two common uropathogens under different nutritional conditions that may have significant role on the regulation of virulence, pathogenicity and in the kidney stone disease.

Prevalence of Coagulase Negative Strains of Staphylococcus aureus in Clinical Specimens at the University of Benin Teaching Hospital, Benin City, Nigeria

The test for coagulase activity is a simple and non-expensive test for the identification of S. aureus strains from clinical samples in resource-poor settings. The results of these tests have been reported to vary with the source of plasma and with some atypical strains that test negative with the coagulase test. The study was carried out to determine if misidentification of strains of S. aureus exists on account of the reliance on the coagulase tests. Clinical isolates of Staphylococci that tested negative by the coagulase tests from wounds, pus, aspirates, blood cultures and urogenital samples were collected and re-tested by the slide and tube coagulase tests and confirmed to be negative. Each isolate was inoculated onto mannitol sat agar and DNAse agar plates and incubated at 37oC for 18 h. Isolates that fermented mannitol and showed a positive DNAse test were 25/366 (6.8%). The highest number of coagulase-negative Staphylococcus aureus (CNSA) occurred within blood culture samples 25.7% and in wound, pus and aspirates, 6.9% and the least proportion, 2.9% from urogenital samples. The generation of CNSA strains is strongly associated with severely-ill patients and the potential for the administration of cell-wall inhibiting antibacterial agents may have important roles to play in the emergence CNSA. The inclusion of DNAse test in the routine identification of staphylococci is advocated especially when an isolate has tested coagulase-negative.

Trinickia violacea sp. nov. and Trinickia terrae sp. nov., isolated from forest soil.

Two Gram-stain negative, aerobic and rod-shaped bacterial strains, DHOD12T and 7GSK02T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain DHOD12T grew at 4-42 °C (optimum, 28-33 °C), pH 4.0-8.5 (optimum, pH 5.5-6.5) and in the presence of 0-1.5 % (w/v; optimum, 0-0.5 %)NaCl; while strain 7GSK02T grew at 12-42 °C (optimum, 28-33 °C), pH 4.0-8.5 (optimum, pH 5.0-6.0) and in the presence of 0-0.5 % (w/v; optimum, 0 %) NaCl. Strains DHOD12T and 7GSK02T had the highest 16S rRNA sequence similarities of 98.0 and 98.3 % with the same species Trinickia mobilis DHG64T, respectively, and 98.4 % between themselves. In the 16S rRNA phylogeny, they formed a clade that was sister to a major cluster consisting of all described Trinickia species. Phylogenomic analyses with the UBCG and PhyloPhlAn methods consistently showed that strains DHOD12T and 7GSK02T formed a clade with T. mobilis DHG64T that was a sister of a cluster containing the remainder of the Trinickia species. The DNA G+C contents of strains DHOD12T and 7GSK02T were 63.1 and 64.6 mol%, respectively. Digital DNA-DNA hybridization and average nucleotide identity values of strains DHOD12T, 7GSK02T and their closely related strains were in the ranges of 21.6-31.4 % and 77.1-86.9 %, respectively. These two strains had the same major respiratory quinone, ubiquinone-8, and both had C16 : 0, C17 : 0 cyclo and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) as their major fatty acids. Their major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Genomic analysis indicated that the two strains could have the potential to degrade aromatic compounds like other Trinickia species. On the basis of phenotypic and phylogenetic results, strains DHOD12T and 7GSK02T represent two novel species of the genus Trinickia, for which the names Trinickia violacea sp. nov. (type strain DHOD12T=LMG 30258T=CGMCC 1.15436T) and Trinickia terrae sp. nov. (type strain 7GSK02T=CGMCC 1.15432T=KCTC 62468T) are proposed.

A light-driving magnetic nanocomposite based on Zn/Fe/Cu embedded in HKUST-1 applied for adsorption/degradation of Indigo carmine and pathogens

An environmentally friendly photocatalytic system (type-II heterojunction) is designed and utilized for rapid removal of Indigo carmine (IC) and pathogens from aqueous samples. This photocatalyst contains ZnFe2O4 magnetic NPs, CuO semiconductor, β-cyclodextrin (β-CD) charge transferor, and HKUST-1 light harvester. After the adsorption and photodegradation process, the nanocomposite was separated magnetically, and the supernatant was taken for the UV-Vis analysis. The maximum adsorption and photodegradation efficiency of 94.45% and 97.67% (pH = 5, in 35 min) were obtained under blue LED light (7.0 W) irradiation, due to the calculations based on UV-Vis spectrophotometer results. Simple preparation via a self-assembly route and facile separation through a superparamagnetic behavior (leading to great recovery) can be mentioned as the most brilliant excellence. Moreover, the photocatalytic performance of this magnetic nanocomposite was preserved after five recycle runs without any substantial reduction in photocatalytic activity. Also, employing a biopolymer, affordability, availability of the raw materials, good thermal stability, facile magnetic separation, simple operation, and high efficiency are upsides of the prepared nanocomposite, making it a superior photocatalyst to previous analogous systems. This nanocomposite (formulated as ZnFe2O4-CuO@β-CD)/HKUST-1) also exhibited antibacterial activity against Gram-positive and -negative strains. Based on BET (porosity) evaluations, the nanocomposite has rendered a surface area of 451.52 m2/g, which led to great adsorption results representing first-order and pseudo-second-order (Freundlich isotherm) kinetic models for the degradation and adsorption processes, respectively.

Novel family of [RuCp(N,N)(P)]+ compounds with simultaneous anticancer and antibacterial activity: Biological evaluation and solution chemistry studies

A family of ten novel ruthenium(II)-cyclopentadienyl organometallics of general formula [Ru(η5-C5H5)(N,N)(PPh2(C6H4COOR)][CF3SO3] (1–10) in which (N,N) = 4,4′-R′-2,2′-bipyridyl (R = –H or –CH2CH2OH; R’ = –H, –CH3, –OCH3, –CH2OH, and –CH2-biotin) was prepared from [Ru(η5-C5H5)(PPh2(C6H4COOH))2Cl]. All compounds were fully characterized by means of several spectroscopic and analytical techniques, and the molecular structures of [Ru(η5-C5H5)(PPh2(C6H4COOH))2Cl], 1, 3 and 4 have been additionally studied by single-crystal X-ray diffraction. The anticancer activity of all compounds was evaluated in sensitive and multidrug-resistant counterpart cell lines from human colorectal cancer (Colo 205 and Colo 320) and non-small cell lung cancer NSCLC (A549, NCI–H460 versus NCI–H460/R) as well. Notably, compounds 6 and 7 (R CH2CH2OH and (N,N) = bipy or Me2bipy, respectively) showed antiproliferative effect against both cell lines with high intrinsic selectivity towards cancer cells. The antibacterial activity of all compounds was also evaluated against both Gram negative and Gram positive strains, and some compounds in the series showed potent antibacterial activity against Staphylococcus aureus strains, including the methicillin-resistant MRSA strains.Solution speciation studies revealed that the complexes bearing the PPh2(C6H4COO−) ligand are neutral at physiological pH (7.4) in contrast with their ethylene glycol derivatives that have a permanent positive charge. While all compounds are lipophilic, the difference in the distribution coefficient for neutral and charged complexes is around one order of magnitude. Complexes 6 and 7 exhibited excellent biological activity and were selected for further studies. Spectrofluorometric methods were used to investigate their interaction with biomolecules such as human serum albumin (HSA) and calf thymus DNA (ct-DNA). For these complexes, binding site II of HSA is a possible binding pocket through non-covalent interactions. The release of ethidium from the DNA adduct by the charged complexes proves their interaction with DNA in contrast to the neutral ones.In conclusion, Ru(II)-cyclopentadienyl complexes with 2,2′-bipyridyl-derivatives and an ethylene glycol moiety tethered to the phenylphosphane co-ligand are very promising from a therapeutic perspective, in particular complexes 6 and 7 that display remarkable antibacterial activity with a high anti-proliferative effect against colon and non-small cell lung cancers, both clinically challenging neoplasias in need of effective solutions.

Euphorbia royleana Boiss Derived Silver Nanoparticles and Their Applications as a Nanotherapeutic Agent to Control Microbial and Oxidative Stress-Originated Diseases.

Nanotechnology is one of the most advance and multidisciplinary fields. Recent advances in nanoscience and nanotechnology radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. The use of plants and their extracts is one of the most valuable methods towards rapid and single-step protocol preparation for various nanoparticles, keeping intact "the green principles" over the conventional ones and proving their dominance for medicinal importance. A facile and eco-friendly technique for synthesizing silver nanoparticles has been developed by using the latex of Euphorbia royleana as a bio-reductant for reducing Ag+ ions in an aqueous solution. Various characterization techniques were employed to validate the morphology, structure, and size of nanoparticles via UV-Vis spectroscopy, XRD, SEM, and EDS. FTIR spectroscopy validates different functional groups associated with biomolecules stabilizing/capping the silver nanoparticles, while SEM and XRD revealed spherical nanocrystals with FCC geometry. The results revealed that latex extract-mediated silver nanoparticles (LER-AgNPs) exhibited promising antibacterial activity against both gram-positive and -negative bacterial strains (Bacillus pumilus, Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, and Streptococcus viridians). Both latex of E. royleana and LER-AgNPs were found to be potent in scavenging DPPH free radicals with respective EC50s and EC70s as 0.267% and 0.518% and 0.287% and 0.686%. ROSs produced in the body damage tissue and cause inflammation in oxidative stress-originated diseases. H2O2 and OH* scavenging activity increased with increasing concentrations (20-100 μg/mL) of LER-AgNPs. Significant reestablishment of ALT, AST, ALP, and bilirubin serum levels was observed in mice intoxicated with acetaminophen (PCM), revealing promising hepatoprotective efficacy of LER-AgNPs in a dose-dependent manner.

RNA-based antibiotic susceptibility testing of tmexCD-toprJ-mediated tigecycline resistance in Klebsiella pneumoniae

The emergence and prevalence of plasmid-encoded RND-type efflux pump TMexCD-TOprJ severely compromise tigecycline treatment, which is recognized as the last resort for multidrug-resistant (MDR) Gram-negative bacterial infections. There is an urgent need for rapid antibiotic susceptibility testing (AST) that can simultaneously identify the genotype and phenotype of tmexCD-toprJ-positive bacteria. Through characterizing transcriptional profiling responses of tmexCD-toprJ-positive and -negative strains after exposure to 2 μg/mL tigecycline, here we identified 12 differentially RNA biomarkers and developed an RNA-based AST (RBAST) to distinguish tmexCD-toprJ-positive and -negative K. pneumoniae. These mRNA biomarkers were successfully validated in tigecycline exposure time variations, concentration shifts, and other tmexCD-toprJ variants. In addition, a group of clinical isolated strains was effectively distinguished using RBAST, with an accuracy of over 94% during 3 h test period. Our work highlights the potential of RNA transcripts as biomarkers for rapid AST, which will contribute to deploying effective antibiotic regimens in clinical practice.

Complete genome sequences of α-glucosidase-positive and -negative strains of Nocardia seriolae from Seriola species in Japan.

We report complete genome sequences of two strains of Nocardia seriolae, the causative agent of nocardiosis in fish. Strains KGN1266 (α-glucosidase-positive) and 024013 (α-glucosidase-negative) were isolated from Seriola dumerili and Seriola quinqueradiata, respectively. Whole genome sequences were hybrid-assembled using Oxford Nanopore long-read and BGI DNBseq short-read sequencing.

Accelerating Full-Thickness Wound Healing with Bacterial Cellulose-Based Multilayer Composites

Materials that speed up wound healing can be of great benefit to patients and healthcare providers. One-layer dressings, however, have unsatisfactory healing efficacy since it is impossible to use materials with different properties simultaneously, and drug delivery is limited by the depth of penetration. The present study utilized a multilayer wound dressing composed of bacterial cellulose (BC) hydrogel, gelatin/alginate (Gel/Alg) hydrogel, and polycaprolactone (PCL) nanofibers loaded with ciprofloxacin (CIP) to promote the healing process in vivo. The designed dressings showed significant water absorption and sufficient water vapor transmission rate (WVTR) after one week, confirming their ability to absorb wound exudate. Within the first four hours, significant amounts of CIP were released from the drug-containing dressing. Then, between hours 4 and 24, the rate decreased and plateaued on day 9. Both positive and negative bacterial strains were inhibited by the gradual release of CIP, while fibroblasts retained their normal morphology and metabolic activity. Lastly, in vivo tests demonstrated that CIP-loaded multilayer dressings could significantly speed up full-thickness wound healing during 14 days, by reducing inflammation, stimulating re-epithelialization, and enhancing skin regeneration. Our findings indicate that multilayering BC hydrogels with drug-loaded nanofibers provide a promising way to promote wound healing by utilizing all the distinctive properties of these layers.

Iodine functionalized 2,5-dimethoxy-2,5-dihydrofuran (DHFI) crosslinked whey protein-derived carbon nanodots (WCND) for antibacterial application

Whey protein-derived carbon nanodots (WCND) were synthesized using the microwave irradiation method, and its amine-rich surface functionality was crosslinked with covalently bound Iodine functionalized 2,5-dimethoxy-2,5-dihydrofuran (DHFI) to produce WCND-DHFI. The physicochemical characterization of both WCND and WCND-DHFI was performed and compared to comprehend the consequence of iodination on the characteristics of WCND. The suitability of CND in biological environments was evaluated through in vitro cytocompatibility and Chorioallantoic Membrane (CAM) assay, as well as a hemocompatibility study. WCND-DHFI has shown enhanced cell viability against WCND. Further, the antibacterial properties of both CNDs were studied against both gram-positive and gram-negative bacterial strains, representing an enhancement in antibacterial activity after DHFI crosslinking. WCND-DHFI has depicted a stable and prominent bacteriostatic activity for up to 6 h for both strains of bacteria. WCND-DHFI has denoted a 99.996% and 99.999% loss of bacterial viability for gram-positive and negative strains, respectively. Novel surface functionalization portrays an improvement in antibacterial activity. Transmission and scanning electron microscopy represent the cell wall rupturing by the WCND-DHFI, resulting in bacterial death. The ROS-mediated bacteriostatic mechanism of WCND-DHFI has been explored through assessing lipid peroxidation and protein oxidation assay. Moreover, the oxidative damage of DNA also has been explored. WCND-DHFI is performing as a promising cytocompatible and hemocompatible material for antibacterial applications.

Environmentally benign, bright luminescent carbon dots from IV bag waste and chitosan for antimicrobial and bioimaging applications

Luminescent carbon dots have gained significant attention in various fields due to their unique optical properties and potential applications. Here, the study was aimed to propose a novel and sustainable approach for the synthesis of luminescent carbon dots (ICDs) using IV (Intravenous) medical bag waste. The ICDs were synthesized through a facile and cost-effective method that involved the carbonization of IV bag waste followed by surface functionalization with chitosan. The synthesized ICDs were characterized using UV–Visible spectrum (UV–Vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The size of the ICDs is between 2 and 8 nm. The ICDs effectively inhibited the growth of both gram positive and gram negative bacterial strains with the inhibitory activity in the range of 11–14 mm and 12–18 mm, respectively. Results of antibiofilm activity of ICDs varying concentrations (50 and 100 μg/ml) showed that it effectively distorted the biofilm architecture and thereby validated its promising potentials. In vitro antioxidant activity showed remarkable DPPH radical scavenging potentials of ICDs (33.4%–70.1%). Results of MTT assay revealted that ICDs showed potent cytotoxic effect on HeLa cells in a dose dependant matter (25–400 μg/ml). Furthermore, when HeLa cells were excited at wavelengths of 380 nm, 440 nm and 540 nm, cell-imaging experiments using ICDs revealed the presence of blue, green, and red fluorescence. This innovative method not only addresses the issue of IV bag waste in a sustainable manner but also opens up exciting possibilities for the advancement of versatile carbon-based materials in the field of biomedicine.

Insights on the structural characteristics and molecular dynamic studies of methyl vanillin Schiff base bio-compounds

A new crystalline form of Schiff base, N-cyclohexyl-1-(3,4-dimethoxyphenyl)methanimine (CHADMB) was obtained from methanolic solution of cylohexylamine and (methylvanillin) 3,4dimethoxybenzaldehyde. Single crystal X-ray diffraction study reveals that the compound crystallized in monoclinic crystal system with P21/c space group having four molecules per unit cell (Z = 4). Hirshfeld surface (HS) analysis and 2D fingerprint plots reveals that weak non-covalent interactions are responsible for crystal packing. The UV–Vis spectroscopy study reveals that the optical band gap of the compound is 4.25 eV. The dielectric properties were studied as a function of frequency at room temperature and the results show that these properties can be exploited for optoelectronic applications. Thermal stability of the compound is revealed by thermogravimetric and differential thermogravimetric analysis. The in vitro antimicrobial activity against Gram negative (E. coli and P. aeruginosa and Gram positive (S. aureus ) bacterial strains and two fungal strains (C. albicans and A. niger) were studied by agar well diffusion method. It is found that the Schiff base is inhibiting the growth of the tested species to varying degrees. Molecular docking studies indicate that alkyl-pi and pi-pi weak interactions enhance the binding affinity of Schiff base-protein complexes. Molecular dynamics study reveals interaction of CHADMB complexed with bacterial protein, EC showed maximum stability which is in agreement with experimental result. Communicated by Ramaswamy H. Sarma

Antibacterial efficacy of amla leaves

The present study was carried out to evaluate antibacterial potential of methanolic extract from amla leaves via agar-well diffusion method against two gram positive ( subtilis MTCC2389, MTCC7443) and three gram negative (MTCC4821, MTCC2127, MTCC7162) strains. Susceptibility of plant extract was tested by serial microdilution method (MIC) and agar well diffusion method was determined. The extract showed maximum zone of inhibition against (17.6 mm) followed by (16.5 mm) and (16.2 mm). However, activity was also reported against (15.5 mm) and (15 mm). The different concentrations of extract (10μl and 20μl) were used and the minimum inhibitory concentration (MIC) ranging from 62.5 to 2000 μg/ml was compared with the standard drug Chloramphenicol (5μg). The MIC of methanolic extract was found 550 μg/ml against and The results of present study revealed that leaves of amla possesses antibacterial potential and source of new antibiotics. Therefore, medicinal plants are finding their way into pharmaceuticals, neutralceuticals and food Supplements that could be useful in chemotherapy to control infectious diseases.

Modified physical properties of Ni doped ZnO NPs as potential photocatalyst and antibacterial agents

Hazardous organic dyes, present in the effluents of industries, are continuously polluting the environment. Photodegradation of these dyes on catalyst surface under sunlight irradiation is economic, safe and suitable strategy to protect environment. Hence, the synthesis and applications of Zn1-xNixO (x = 0.00, 0.02, 0.04, 0.06) NPs are reported here. Effect of pH and dopant concentration was studied to modify the electrical, magnetic, antibacterial and photocatalytic properties of Ni doped ZnO NPs. The samples were characterized by Scanning electron microscopy (SEM), Powder X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis.), Energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR) to determine the morphology, crystallite structure, optical properties, elemental composition and functional group detection, respectively. LCR meter and VSM were used to evaluate the dielectric properties and magnetic properties of Ni doped ZnO NPs, respectively. XRD pattern confirmed the presence of hexagonal wurtzite geometry of ZnO NPs. The structural and morphological analysis showed the increase in crystallinity with little effect on shape of doped NPs by increasing the dopant concentration and slight increase of pH. It was observed that the Ni doped ZnO NPs possess good photocatalytic potential by 94% degradation of 20 ppm solution of methyl orange dye (MO) in just 80 min under sunlight. Moreover, the enhancement in antibacterial potential was also observed with increase in dopant concentration and decrease in crystallite size of doped ZnO NPs. Smaller size NPs were found more effective against gram negative bacterial strains.

Layered double hydroxides bundled Agar-g-PAN/Ag nanocomposite films: A strategy to improve thermal, barrier and antibacterial properties

With an aim of designing a biodegradable packaging material with considerable stability, herein, layered double hydroxides (LDH) bundled agar grafted polyacrylonitrile nanocomposites (Agar-g-PAN/Ag/LDH) incorporated with silver nanoparticles (Ag Nps) have been synthesized using surfactant free in situ polymerization method. The LDH platelets form a laminating structure around the Agar-g-PAN copolymeric network while the Ag Nps are dispersed throughout the material. The prepared nanocomposite films exhibit high thermal stability because of the sandwiching of polymeric chains in between the LDH platelets which also evidences the improvement in fire retardancy. The comparative analysis of limiting oxygen indices of Agar-g-PAN/Ag/LDH nanocomposites with PAN and Agar-g-PAN clearly indicates the fire-repellent nature of the materials. Proper exfoliation and partial intercalation of the LDH platelets as well as presence of Ag Nps result in almost five-fold enhancement in oxygen barrier properties of Agar-g-PAN/Ag/LDH nanocomposite films as compared to the copolymeric matrix. The combination of LDH with Ag Nps shows a synergistic effect in improving the biodegradability and chemical resistance of the nanocomposite films. The antibacterial studies indicate remarkable antibacterial properties of the Agar-g-PAN/Ag/LDH nanocomposites which are more pronounced for gram negative bacterial strains. The synthesized nanocomposite films are biodegradable and chemically inert with enhancement in thermal, barrier and antibacterial properties, making them suitable candidates for packaging applications.