Papers by Naveen Kumar Navani
Nanotechnology laying new foundations for combating COVID-19 pandemic
Elsevier eBooks, 2023
Double-Edged Nanobiotic Platform with Protean Functionality: Leveraging the Synergistic Antibacterial Activity of a Food-Grade Peptide to Mitigate Multidrug-Resistant Bacterial Pathogens
ACS Applied Materials & Interfaces, Apr 29, 2022
Journal of Materials Science: Materials in Medicine, Feb 11, 2014
In response to the wide spread of microbial contamination induced by bacterial pathogens, the dev... more In response to the wide spread of microbial contamination induced by bacterial pathogens, the development of novel materials with excellent antibacterial activity is of great interest. In this study, novel antibacterial chitosan (CS) and polyhexamethylene guanidine hydrochloride (PHGC) dual-polymer-functionalized graphene oxide (GO) (GO-CS-PHGC) composites were designed and easily fabricated. The as-prepared materials were characterized by Fourier transform infrared (FTIR), X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. Their antibacterial capability towards bacterial strains was also studied by incubating both Gram-negative bacteria and Gram-positive bacteria in their presence. More significantly, the synergistic antibacterial action of the three components was assayed, and the findings implied that the as-prepared GO-CS-PHGC shows enhanced antibacterial activity when compared to its single components (GO, CS, PHGC or CS-PHGC) and the mixture of individual components. Not only Gram-negative bacteria but also Gram-positive bacteria are greatly inhibited by GO-CS-PHGC composites. The minimum inhibitory concentration (MIC) value of GO-CS-PHGC against E. coli was 32 µg/mL. With the powerful antibacterial activity as well as its low cost and facile preparation, GO-CS-PHGC has potential applications as a novel antibacterial agent in a wide range of biomedical uses.
Carbon Nanotube and Polyacrylonitrile Nanofiber Devices for Sensing Applications
Journal of Electronic Materials, Nov 3, 2021
In this paper, a novel technique is presented to fabricate aligned polymer-wrapped semiconducting... more In this paper, a novel technique is presented to fabricate aligned polymer-wrapped semiconducting carbon nanotube (CNT)-based devices to overcome the issues that arise in randomly oriented CNT network devices. It is challenging to make the CNT-based devices with straight polymer-wrapped CNTs. Straight CNTs have better conductivity than the bended ones. Therefore, we have fabricated simple electrodes of a square pad with the conventional lithography process. Subsequently, dispersed single-walled CNTs (SWNT)-polyacrylonitrile is used to fabricate aligned nanofiber by an electrospinning system on the fabricated electrodes. The average diameter of the fabricated nanofiberr is found to be 100 nm. The current–voltage (I–V) characteristics are investigated for the fabricated devices. The I–V characteristics are similar to those of a back-to-back Schottky diode. The Schottky barrier height and ideality factor of the nanofiber devices are found to be 431 meV and 4.1, respectively. Therefore, the multiple current transport mechanisms (thermionic emission, tunneling, generation-recombination, and leakage) contribute to the current through the nanofiber device. Applications of the devices can include gas sensors, biosensors, and other CNT-based device electronics applications. Graphic Abstract
Journal of Hazardous Materials, 2016
Highlights Pseudomonas sp. RPT 52 utilized three chemically different pesticides as sole carbon... more Highlights Pseudomonas sp. RPT 52 utilized three chemically different pesticides as sole carbon source. Order of rate of degradation was endosulfan > coragen > imidacloprid. Degradation process reduced the toxicity of these pesticides. RPT 52 degraded endosulfan and coragen in soil microcosm. First report of degradation of chemically unrelated pesticides by single bacterial strain.
Isolation and characterization of a protease-producing novel haloalkaliphilic bacterium Halobiforma sp. strain BNMIITR from Sambhar lake in Rajasthan, India
Annals of Microbiology, May 28, 2014
ABSTRACT A novel haloalkaliphilic bacterium designated as strain BNMIITR was isolated from a soil... more ABSTRACT A novel haloalkaliphilic bacterium designated as strain BNMIITR was isolated from a soil sample collected from Sambhar lake, Rajasthan, in northern India. Colonies of the isolated strain were dark orange and comprised Gram-negative bacilli; there was a slight pleomorphism towards the stationary phase of growth. Experiments revealed that the isolate can grow in the range of 2–5 M NaCl, pH 6–11 and 18–55 °C, with optimum growth observed at 3 M NaCl, pH 8–8.5 and 45 °C. No growth was observed in culture medium without NaCl. The isolate showed no requirement for magnesium sulphate heptahydrate (MgSO4 .7H2O) for growth. Major cellular fatty acids were C 14:0, C 15:0 iso, C 15:0 anteiso, C 16:0, C 17:0 iso, C 17:0 anteiso and C 20:2 w6, 9c. The result of 16S rRNA gene sequence analysis showed 98 % sequence similarity with Halobiforma lacisalsi and Hbf. haloterrestris. Halobiforma sp. strain BNMIITR showed resistance towards several antibiotics and produced an extracellular alkaline protease. The crude enzyme was found to be active in broad range of alkaline pH and temperature (30–80 °C).
Archives of Biochemistry and Biophysics, 1998
cally engineered human hemoglobin (2), include Vi-The bacterial and yeast hemoglobins have a glut... more cally engineered human hemoglobin (2), include Vi-The bacterial and yeast hemoglobins have a gluta-treoscilla hemoglobin (VHb) 2 (3) and the microbial flamine instead of histidine in the E7 position of the distal vohemoglobins: yeast flavohemoglobins (4, 5), Escheheme pocket. The recently determined crystal strucrichia coli HMP (6), Alcaligenes eutrophus Hb (7), ture of Vitreoscilla hemoglobin (VHb) indicates that Bacillus subtilis (8), and Erwinia chrysanthemi Hb (9). this residue is oriented out of the heme pocket and The ability of the flavohemoglobins to combine reversmay not ligand the bound oxygen. This is in contrast ibly with oxygen suggests an oxygen storage, trap, or to elephant myoglobin which also has a Gln(E7) but sensing function; other proposed functions include anwhich does ligand the bound oxygen. This residue was aerobic nitrite respiration in A. eutrophus (7), plant changed in VHb using site-directed mutagenesis to pathogenicity in E. chrysanthemi (9), and electron leucine (VHbL) or to histidine (VHbH). Spectral and transfer in E. coli (6). Yeast FHP is expressed at a high kinetic studies of the binding of oxygen and CO to level under oxygen-replete conditions and may have a VHbL showed that this substitution had little effect on function distinct from that of the bacterial globins (10). the ligand-binding properties of this protein, evidence The Vitreoscilla hemoglobin has been of particular inthat Gln(E7) does not H-bond the bound ligand, in terest because of its potential use in aerobic fermentaagreement with the findings of the crystallographic tions; its presence in genetically engineered organisms study of VHb. In contrast, the functional properties of usually enables better growth under oxygen-limiting VHbH were drastically altered in a way suggesting conditions and increased product formation (11, 12). that the E7His may itself be liganded to the heme iron. Its unique oxygen-binding properties are presumed to These studies are further evidence that the distal contribute to its postulated role of facilitating respiraheme pocket in VHb and related microbial hemoglotion under hypoxic conditions (13, 14), especially its bins differs from that in mammalian hemoglobins and rate constant for oxygen dissociation (k off) which is unmay resemble in some ways the heme pocket in cytousually large (15). These oxygen binding properties of chrome b 5 .
Current Science
This article presents applications of metagenomics and metabolomics in geosciences. It emphasizes... more This article presents applications of metagenomics and metabolomics in geosciences. It emphasizes the significance of biomolecular proxies in palaeoclimatology, the evolution of life, the genesis of hydrocarbons and the role of biological processes in metallogeny. Several examples of breakthroughs with respect using these methods in earth sciences exist, such as the estimating resilience time of landscapes against invasive species. It is unfortunate that scientific programmes using bioproxies have not yet taken root in Indian institutions. Now is the appropriate time to delineate the critical role of biology in geology and establish it as a thrust area of research in India. A molecular geobiology programme would deal with the understanding of varied issues such as microbial heat production and its role in soil processes, the role of biology in mineralization, the use of biomarkers (metabolites) and ancient DNA studies in understanding feedbacks in climate change, evolution of life, etc. This article focuses on the use of metagenomics and metabolomics in palaeo-sciences and the potential intellectual dividends they could provide.
Genetic regulatory element based whole-cell biosensors for the detection of metabolic disorders
Biosensors and Bioelectronics, 2022
Clinicians require simple, and cost-effective diagnostic tools for the quantitative determination... more Clinicians require simple, and cost-effective diagnostic tools for the quantitative determination of amino acids in physiological fluids for the detection of metabolic disorder diseases. Besides, amino acids also act as biological markers for different types of cancers and cardiovascular diseases. Herein, we applied an in-silico based approach to identify potential amino acid-responsive genetic regulatory elements for the detection of metabolic disorders in humans. Identified sequences were further transcriptionally fused with GFP, thus generating an optical readout in response to their cognate targets. Screening of genetic regulatory elements led us to discover two promoter elements (pmetE::GFP and ptrpL::GFP) that showed a significant change in the fluorescence response to homocysteine and tryptophan, respectively. The developed biosensors respond specifically and sensitively with a limit of detection of 3.8 μM and 3 μM for homocysteine and tryptophan, respectively. Furthermore, the clinical utility of this assay was demonstrated by employing it to identify homocystinuria and tryptophanuria diseases through the quantification of homocysteine and tryptophan in plasma and urine samples within 5 h. The precision and accuracy of the biosensors for disease diagnosis were well within an acceptable range. The general strategy used in this system can be expanded to screen different genetic regulatory elements present in other gram-negative and gram-positive bacteria for the detection of metabolic disorders.
PMU1, an integrating reporter plasmid
<b>Copyright information:</b>Taken from "A synthetic gene cluster optimized for ... more <b>Copyright information:</b>Taken from "A synthetic gene cluster optimized for expression in high-GC bacteria"Nucleic Acids Research 2007;35(6):e46-e46.Published online 1 Mar 2007PMCID:PMC1874620.© 2007 The Author(s) , the major transcriptional terminator of phage ; , transcriptional terminator of phage λ; , the origin of replication from pUC18; apramycin-resistance cassette selectable in and , origin of transfer from the RK2 plasmid; and , the integrase gene and attachment site of the ΦBT1 phage, respectively. The multiple cloning site consists of EcoRV, BamHI and KpnI site (non-unique sites are marked with*). The multiple cloning site is followed by translational stop codons in all three reading frames (S1, S2, S3) and a ribosome binding site (RBS).
Combination of plant based natural products and food grade chemicals as alternatives to antibiotics for poultry
Activity of the operon in when grown on solid media
<b>Copyright information:</b>Taken from "A synthetic gene cluster optimized for ... more <b>Copyright information:</b>Taken from "A synthetic gene cluster optimized for expression in high-GC bacteria"Nucleic Acids Research 2007;35(6):e46-e46.Published online 1 Mar 2007PMCID:PMC1874620.© 2007 The Author(s) plux, plux, plux and pMU1 were introduced into wild-type M145 and developmental mutants , and . () M145 containing the promoter fusions grown on R2YE. () M145 containing the promoter fusions grown on SFM. () mutant strain containing the promoter fusions grown on R2YE. () mutant strain containing the promoter fusions grown on R2YE. () mutant strain containing the promoter fusions grown on R2YE.
Archives of Biochemistry and Biophysics, 1998
cally engineered human hemoglobin (2), include Vi-The bacterial and yeast hemoglobins have a glut... more cally engineered human hemoglobin (2), include Vi-The bacterial and yeast hemoglobins have a gluta-treoscilla hemoglobin (VHb) 2 (3) and the microbial flamine instead of histidine in the E7 position of the distal vohemoglobins: yeast flavohemoglobins (4, 5), Escheheme pocket. The recently determined crystal strucrichia coli HMP (6), Alcaligenes eutrophus Hb (7), ture of Vitreoscilla hemoglobin (VHb) indicates that Bacillus subtilis (8), and Erwinia chrysanthemi Hb (9). this residue is oriented out of the heme pocket and The ability of the flavohemoglobins to combine reversmay not ligand the bound oxygen. This is in contrast ibly with oxygen suggests an oxygen storage, trap, or to elephant myoglobin which also has a Gln(E7) but sensing function; other proposed functions include anwhich does ligand the bound oxygen. This residue was aerobic nitrite respiration in A. eutrophus (7), plant changed in VHb using site-directed mutagenesis to pathogenicity in E. chrysanthemi (9), and electron leucine (VHbL) or to histidine (VHbH). Spectral and transfer in E. coli (6). Yeast FHP is expressed at a high kinetic studies of the binding of oxygen and CO to level under oxygen-replete conditions and may have a VHbL showed that this substitution had little effect on function distinct from that of the bacterial globins (10). the ligand-binding properties of this protein, evidence The Vitreoscilla hemoglobin has been of particular inthat Gln(E7) does not H-bond the bound ligand, in terest because of its potential use in aerobic fermentaagreement with the findings of the crystallographic tions; its presence in genetically engineered organisms study of VHb. In contrast, the functional properties of usually enables better growth under oxygen-limiting VHbH were drastically altered in a way suggesting conditions and increased product formation (11, 12). that the E7His may itself be liganded to the heme iron. Its unique oxygen-binding properties are presumed to These studies are further evidence that the distal contribute to its postulated role of facilitating respiraheme pocket in VHb and related microbial hemoglotion under hypoxic conditions (13, 14), especially its bins differs from that in mammalian hemoglobins and rate constant for oxygen dissociation (k off) which is unmay resemble in some ways the heme pocket in cytousually large (15). These oxygen binding properties of chrome b 5 .
PLOS ONE, 2019
Characterization of milk fat globule (MFG) was performed to investigate the difference in MFG mem... more Characterization of milk fat globule (MFG) was performed to investigate the difference in MFG membrane (MFGM) between fresh and mastitis Holstein Friesian cow milk. Lipid distribution investigated by exogenous phospholipids using microscopy showed higher phospholipid content in fresh compared to mastitic MFGM. Xanthine oxidase assay indicative of membrane impairment revealed lower activity in mastitic samples compared to fresh globules. Of note, significantly higher roughness of globule surface and zeta potential was observed in mastitis compared to fresh globules. Influence of globule membrane on the interaction with L. fermentum demonstrated preferential adhesion of bacteria to fresh compared to mastitic globules including enhanced extent of binding. Results of the present study provides an insight of the interfacial changes occurring at the globule surface as well as highlighting the importance of selective bacterial interaction with milk components for the potential development of functional food with relevance to human health.
Nitric oxide scavenging and detoxification by the Mycobacterium tuberculosis haemoglobin, HbN in Escherichia coli
Molecular Microbiology, 2002
Nitric oxide (NO), generated in large amounts within the macrophages, controls and restricts the ... more Nitric oxide (NO), generated in large amounts within the macrophages, controls and restricts the growth of internalized human pathogen, Mycobacterium tuberculosis H37Rv. The molecular mechanism by which tubercle bacilli survive within macrophages is currently of intense interest. In this work, we have demonstrated that dimeric haemoglobin, HbN, from M. tuberculosis exhibits distinct nitric oxide dioxygenase (NOD) activity and protects growth and cellular respiration of heterologous hosts, Escherichia coli and Mycobacterium smegmatis, from the toxic effect of exogenous NO and the NO-releasing compounds. A flavohaemoglobin (HMP)-deficient mutant of E. coli, unable to metabolize NO, acquired an oxygen-dependent NO consumption activity in the presence of HbN. On the basis of cellular haem content, the specific NOD activity of HbN was nearly 35-fold higher than the single-domain Vitreoscilla haemoglobin (VHb) but was sevenfold lower than the two-domain flavohaemoglobin. HbN-dependent NO consumption was sustained with repeated addition of NO, demonstrating that HbN is catalytically reduced within E. coli. Aerobic growth and respiration of a flavohaemoglobin (HMP) mutant of E. coli was inhibited in the presence of exogenous NO but remained insensitive to NO inhibition when these cells produced HbN, VHb or flavohaemoglobin. M. smegmatis, carrying a native HbN very similar to M. tuberculosis HbN, exhibited a 7.5-fold increase in NO uptake when exposed to gaseous NO, suggesting NO-induced NOD activity in these cells. In addition, expression of plasmid-encoded HbN of M. tuberculosis in M. smegmatis resulted in 100-fold higher NO consumption activity than the isogenic control cells. These results provide strong experimental evidence in support of NO scavenging and detoxification function for the M. tuberculosis HbN. The catalytic NO scavenging by HbN may be highly advantageous for the survival of tubercle bacilli during infection and pathogenesis.
Aptamers, 2019
Aptamers generated de novo by iterative process of in-vitro selection called Systemic Evolution o... more Aptamers generated de novo by iterative process of in-vitro selection called Systemic Evolution of Ligand by EXponential enrichment (SELEX) which mimics Darwinian evolution process. SELEX is a powerful and yet simple technique that has been used to isolate DNA or RNA sequences with a function of interest (e.g. ligand-binding or catalysis) from a pool of random-sequence oligonucleotides based on their ability to bind to various types of different targets. Aptamers also known as chemicalbodies because of nature of selection and similarity in their action to antibodies. Aptamers have become attractive molecules in diagnostics and therapeutics rivaling and, in some cases, and extends many features of other molecular probes such as antibodies because of their nanomolar affinities and high specificities toward target molecule, amenable to various modifications, non-immunogenic nature and flexible structure properties. Recently, an increasing number of aptamers have been developed against various biomarkers expressed at the surface of mammalian cells or pathogenic microrganisms. This class of targets (mostly proteins) is associated with several pathologies including cancer, inflammation and infection diseases. Several of these aptamers were tested in-vivo as drugs or as targeting agents for site specific drug delivery, siRNA, microRNA or molecular imaging and may prove useful in the treatment of a wide variety of human maladies, including infectious diseases, cancer, and cardiovascular diseases. In this book chapter, we review the observations that expedited the development of this emerging class of therapeutics and speculate on the efficacy in the clinical studies.
Draft Genome Sequence of Alkalihalobacillus clausii Strain AXA-BCL3, Isolated from the Sahastradhara Springs of Uttarakhand, India
Microbiology Resource Announcements
Here, we report the draft genome sequence of Alkalihalobacillus clausii strain AXA-BCL3, which wa... more Here, we report the draft genome sequence of Alkalihalobacillus clausii strain AXA-BCL3, which was isolated from a soil sample from the Sahastradhara springs of Uttarakhand, India. The genome was assembled in 125 contigs with a total length of 4,428,477 bp and a GC content of 44.5%. Genome annotation predicted 4,278 protein-coding genes and 75 tRNA genes.
Fabrication and Characterization of Carbon Nanotube Microdevices for CO2 Gas Sensing and Other Applications
2019 International Conference on Electrical, Electronics and Computer Engineering (UPCON), 2019
PCB mounted sensor with high sensitivity SWNT-Based devices for gas sensing applications
Microelectronics Journal, 2021
Abstract In this paper, the fabrication of aligned semiconducting single-walled carbon nanotube (... more Abstract In this paper, the fabrication of aligned semiconducting single-walled carbon nanotube (SWNT) devices on a thermally grown silicon dioxide (SiO2) over silicon (Si) substrate is presented. The SWNTs are aligned between the nickel fingers that are patterned on the substrate. Subsequently, the fabricated devices are bonded onto a low-cost printed circuit board (PCB) with wire bonder. The mounted sensors have been tested for carbon dioxide (CO2) gas, acetone, and isopropyl alcohol (IPA) vapor sensing at room temperature. The sensitivity values of 27% for the concentration of 15000 ppm of CO2, 52% for the concentration of 7000 ppm of acetone, and 67% for the concentration of 900 ppm of IPA have been observed with good response and recovery times. The fabricated sensors show better performance than the already reported sensors.
A chemical genetic approach using genetically encoded reporters to detect and assess the toxicity of plant secondary metabolites against bacterial pathogens
Journal of Hazardous Materials, 2021
Plant secondary metabolites are emerging as attractive alternatives in the development of therape... more Plant secondary metabolites are emerging as attractive alternatives in the development of therapeutics against infectious and chronic diseases. Due to the present pandemic, therapeutics showing toxicity against bacterial pathogens and viruses are gaining interest. Plant metabolites of terpenoid and phenylpropanoid categories have known antibacterial and antiviral properties. These metabolites have also been associated with toxicity to eukaryotic cells in terms of carcinogenicity, hepatotoxicity, and neurotoxicity. Sensing methods that can report the exact antibacterial dosage, formation, and accumulation of these antibacterial compounds are needed. The whole-cell reporters for such antibacterial metabolites are cost-effective and easy to maintain. In the present study, battery of toxicity sensors containing fluorescent transcriptional bioreporters was constructed, followed by fine-tuning the response using gene-debilitated E. coli mutants. This study shows that by combining regulatory switches with chemical genetics strategy, it may be possible to detect and elucidate the mode of action of effective antibacterial plant secondary metabolites - thymol, cinnamaldehyde, eugenol, and carvacrol in both pure and complex formats. Apart from the detection of adulteration of pure compounds present in complex mixture of essential oils, this approach will be useful to detect authenticity of essential oils and thus reduce unintended harmful effects on human and animal health.
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Papers by Naveen Kumar Navani