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The agar overlay TLC-bioautography is one of the crucial methods for simultaneous in situ detection and separation of antimicrobial metabolites of pharmaceutical interest. The main focus of this research relies on the dereplication of an antimicrobial metabolite coriloxin derived from mycoendophytic Xylaria sp. NBRTSB-20 with a validation of agar overlay TLC-bioautography technique. This polyketide metabolite coriloxin was purified by column chromatography, and its purity was assessed by HPLC, UPLC-ESI-QTOF-MS, FT-IR and NMR spectral analysis. The antimicrobial capability of ethyl acetate extract and the purified compound coriloxin was determined by disc diffusion, minimal inhibitory concentration and agar overlay TLC-bioautography assay. The visible LOD of coriloxin antimicrobial activity was found at 10 μg for Escherichia coli and 20 μg for both Staphylococcus aureus and Fusarium oxysporum. Inter- and intra-day precision was determined as the relative standard deviation is less than 6.56%, which proved that this method was precise. The accuracy was expressed as recovery, and the values were found ranging from 91.18 to 108.73% with RSD values 0.94-2.30%, respectively. The overall findings of this investigation suggest that agar overlay TLC-bioautography assay is a suitable and acceptable method for the in situ determination of antimicrobial pharmaceuticals., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

For combating multidrug-resistant microorganisms, exploration of natural compounds from plant endophytes increases the chance of finding novel compounds. An efficient bioactive metabolites producing endophytic fungal strain AE1 was isolated from leaves of Azadirachta indica A. Juss. The metabolites were found to be thermostable, non-proteinacious and produced prominent zones of inhibition against numbers of Gram positive and Gram negative bacteria. Based on 28S rDNA (D1/D2) sequence homology the isolate AE1 was identified as Alternaria alternata. Malt extract broth was found effective for the maximum production of bioactive metabolites by the isolate and was subjected for solvent extraction. The Ethyl acetate (EA) fraction of AE1 showed MIC values of 300-400 μg/ml against Gram positive and Gram negative bacteria tested. The cidal mode of action of EA fraction was detected by treating bacterial cultures at mid log phase. Scanning electron microscopic study supported morphological disintegration of bacterial cells. Release of nucleic acid, protein and potassium ions (K+) also suggested lysis of bacterial cells or leakage of cell membrane upon treatment. In addition, reduction of the activity of EMP pathway, TCA cycle and gluconeogenic enzymes in all bacteria suggested the interference of antibacterial principles with central carbohydrate metabolic pathways. Thin layer chromatographic separation followed by GC-MS analysis of EA fraction suggested numbers of antimicrobial compound production by AE1. In addition, DPPH free radical as well as superoxide radical scavenging assay also suggested strong antioxidant potential of AE1 with an IC50 value of 38.0±1.7 μg/ml and 11.38±1.2 μg/ml respectively. On the basis of above facts it can be concluded that the strain AE1 will be a good source of bioactive compounds having medicinal importance., Competing Interests: The authors have declared that no competing interests exist.

Carbon dots with heteroatom co-doping associated with consummate luminescence features are of acute interest in diverse applications such as biomolecule markers, chemical sensing, photovoltaic, and trace element detection. Herein, we demonstrate a straightforward, highly efficient hydrothermal dehydration technique to synthesize zinc and nitrogen co-doped multifunctional carbon dots (N, Zn-CDs) with superior quantum yield (50.8%). The luminescence property of the carbon dots can be tuned by regulating precursor ratio and surface oxidation states in the carbon dots. A unique attribution of the as-prepared carbon dots is the high monodispersity and robust excitation-independent emission behavior that is stable in enormously reactive environment and over a wide range of pH. These N, Zn-CDs unveils captivating bacteriostatic activity against gram-negative bacteria Escherichia coli. Furthermore, the excellent luminescence properties of these carbon dots were applied as a platform of sensitive biosensor for the detection of hydrogen peroxide. Under optimized conditions, these N, Zn-CDs reveals high sensitivity over a broad range of concentrations with an ultra-low limit of detection (LOD) indicating their pronounced prospective as a fluorescent probe for chemical sensing. Overall, the experimental outcomes propose that these zero-dimensional nano-dots could be developed as bacteriostatic agents to control and prevent the persistence and spreading of bacterial infections and as a fluorescent probe for hydrogen peroxide detection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Antimicrobial susceptibility testing of 258 Neisseria gonorrhoeae isolates by Etest determined that 60.1% were multidrug resistant (MDR), while 5% of the strains had decreased susceptibility to currently recommended extended-spectrum cephalosporins (ESCs). Among these, 84.5% of MDR strains and 76.9% of strains that had decreased susceptibility to ESCs were susceptible to gentamicin. No MDR isolate was resistant to gentamicin. These in vitro results suggest that gentamicin might be an effective treatment option for the MDR strains and in dual therapy for gonorrhea. However, further research regarding the clinical treatment outcomes is essential., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Introduction: Most human orofacial infections originate from odontogenic infections and prescribing antibiotics has become a ubiquitous phenomenon. The World Health Organization (WHO) has recognized the inappropriate, indiscriminate, and irrational use of antibiotics leading to antibiotic resistance as a global problem., Objective: The objective of this survey is to compare the antibiotic prescription pattern and the awareness of antibiotic resistance among Bachelor of Dental Surgery (BDS) practitioners and pediatric dentists., Materials and Methods: A hundred BDS practitioners and 100 pediatric dentists included in the study were given a questionnaire containing both open-ended and closed-ended questions. The questionnaire comprised information pertaining to antibiotic prescription for most common oral conditions, commonly prescribed antibiotics, their dosage, etc., Results: The majority of the practitioners prescribed antibiotics for managing oral diseases. On comparing the prescription patterns between the BDS practitioners and pediatric dentists, there was an overprescription in the BDS group for many conditions, which was statistically significant. Amoxicillin was the most commonly prescribed drug in both the groups. In the presence of an anaerobic infection, the most preferred drug was a combination of amoxicillin and clavulanic acid with metronidazole. With regard to the duration of antibiotic prescription, 74% BDS practitioners prescribed antibiotics as a 3-day course and 60% pediatric dentists resorted to a 5-day course, which was statistically significant. The awareness regarding antibiotic prophylaxis and antibiotic resistance was found to be adequate in both the groups. However, there was a general lack of awareness with regard to the guidelines for antibiotic prescribing in both the groups., Conclusion: Practitioners should prescribe antibiotics in accordance with the guidelines to curb antibiotic resistance, an emerging public health problem.

Background: Actinomycetes have provided a wealth of bioactive secondary metabolites with interesting activities such as antimicrobial, antiviral and anticancer. The study aims at isolation, characterization and the antimicrobial potentiality of Streptomyces sannanensis SU118 obtained from Phoomdi, a unique habitat of Loktak Lake of Manipur, India., Results: An actinomycete strain isolated from Phoomdi soil of Loktak Lake of Manipur, India was identified as Streptomyces sannanensis SU118. It is a Gram-positive filamentous bacterium which exhibits antimicrobial activity only against Gram-positive bacteria, while Gram-negative organisms were not affected. Glucose Soyabean meal broth was found to be the suitable medium for antibiotic production at 28°C for seven days of incubation. The antimicrobial agent produced by the strain was extracted with ethyl acetate as solvent and purified by thin layer chromatography. Screening and bioassay - guided fractionation of the ethyl acetate extract from the culture filtrate led to the isolation of an active potential compound (R f value 0.56) with λmax 275.0 nm which has got the lowest minimum inhibitory concentration (0.5 μg/ml) against Staphylococcus aureus MTCC 96 and Staphylococcus aureus (clinical isolate), whereas highest (3.0 μg/ml) was recorded against Mycobacterium smegmatis MTCC 6 and Bacillus circulans MTCC 8074., Conclusion: This study has therefore uncovered the potential of exploring virgin untapped habitats in the Indo-Burma biodiversity hot spot region as reservoir of promising antimicrobial metabolite producer. These results highlighted the scope for further characterization of the metabolite and could be a candidate in the generation of new antimicrobial agents.

The physiological role of C-reactive protein (CRP), the classical acute-phase protein, is not well documented, despite many reports on biological effects of CRP in vitro and in model systems in vivo. It has been suggested that CRP protects mice against lethal toxicity of bacterial infections by implementing immunological responses. In Achatina fulica CRP is a constitutive multifunctional protein in haemolymph and considered responsible for their survival in the environment for millions of years. The efficacy of Achatina CRP (ACRP) was tested against both Salmonella typhimurium and Bacillus subtilis infections in mice where endogenous CRP level is negligible even after inflammatory stimulus. Further, growth curves of the bacteria revealed that ACRP (50 microg/mL) is bacteriostatic against gram negative salmonellae and bactericidal against gram positive bacilli. ACRP induced energy crises in bacterial cells, inhibited key carbohydrate metabolic enzymes such as phosphofructokinase in glycolysis, isocitrate dehydrogenase in TCA cycle, isocitrate lyase in glyoxylate cycle and fructose-1,6-bisphosphatase in gluconeogenesis. ACRP disturbed the homeostasis of cellular redox potential as well as reduced glutathione status, which is accompanied by an enhanced rate of lipid peroxidation. Annexin V-Cy3/CFDA dual staining clearly showed ACRP induced apoptosis-like death in bacterial cell population. Moreover, immunoblot analyses also indicated apoptosis-like death in ACRP treated bacterial cells, where activation of poly (ADP-ribose) polymerase-1 (PARP) and caspase-3 was noteworthy. It is concluded that metabolic impairment by ACRP in bacterial cells is primarily due to generation of reactive oxygen species and ACRP induced anti-bacterial effect is mediated by metabolic impairment leading to apoptosis-like death in bacterial cells.

Background: Cephalotaxus spp. are known to possess various therapeutic potentials. Cephalotaxus griffithii, however, has not been evaluated for its biological potential. The reason may be the remoteness and inaccessibility of the habitat where it is distributed. The main aim of this study was to: (1) evaluate multiple biological potentials of stem bark of C. griffithii, and (2) identify solvent extract of stem bark of C. griffithii to find the one with the highest specific biological activity., Methods: Dried powder of stem bark of C. griffithii was exhaustively extracted serially by soaking in petroleum ether, acetone and methanol to fractionate the chemical constituents into individual fractions or extracts. The extracts were tested for total phenolic and flavonoid content, antioxidant (DPPH radical scavenging, superoxide radical scavenging, and reducing power models), antibacterial (disc diffusion assay on six bacterial strains), cytotoxic (MTT assay on HeLa cells), and apoptotic activity (fluorescence microscopy, DNA fragmentation assay, and flow cytometry on HeLa cells)., Results: Among the three extracts of stem bark of C. griffithii, the acetone extract contained the highest amount of total phenolics and flavonoids and showed maximum antioxidant, antibacterial, cytotoxic (IC50 of 35.5 ± 0.6 μg/ml; P < 0.05), and apoptotic (46.3 ± 3.6% sub-G0/G1 population; P < 0.05) activity, followed by the methanol and petroleum ether extracts. However, there was no significant difference observed in IC50 values (DPPH scavenging assay) of the acetone and methanol extracts and the positive control (ascorbic acid). In contrast, superoxide radical scavenging assay-based antioxidant activity (IC50) of the acetone and methanol extracts was significantly lower than the positive control (P < 0.05). Correlation analysis suggested that phenolic and flavonoid content present in stem bark of C. griffithii extracts was responsible for the high antioxidant, cytotoxic, and apoptotic activity (P < 0.05)., Conclusions: Stem bark of C. griffithii has multiple biological effects. These results call for further chemical characterization of acetone extract of stem bark of C. griffithii for specific bioactivity.