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1.
Inorg Chem ; 60(21): 16059-16064, 2021 Nov 01.
Article in English | MEDLINE | ID: mdl-34662098

ABSTRACT

We report a bioinspired heterobimetallic photocatalyst RuIIchrom-FeIIIcat and its relevant applications toward visible-light-driven C-H bond oxidation of a series of hydrocarbons using O2 as the O-atom source. The RuII center absorbs visible light near 460 nm and triggers a cascade of electrons to FeIII to afford a catalytically active high-valent FeIV═O species. The in situ formed FeIV═O has been employed for several high-impact oxidation reactions in the presence of triethanolamine (TEOA) as the sacrificial electron donor.


Subject(s)
Oxygen
2.
Biologicals ; 63: 62-67, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31843357

ABSTRACT

Brucella abortus S19 is an important tool for controlling bovine brucellosis across the globe. However, vaccination with S19 suffers critical shortcomings such as, presence of residual virulence, induction of abortion and sero-diagnostic interference. In this study, rfbD gene deleted mutant S19 was developed. The mutant strain designated S19ΔR displayed rough LPS phenotype, which was confirmed by acriflavine dye-agglutination and LPS-SDS-PAGE analysis. The virulence was amply reduced as suggested by increased sensitivity to complement killing; reduction in splenic-bacterial load and the recovery time RT50 as validated in mice model. Anti-brucella humoral response was significantly lower as compared to S19 immunization. The minimal induction of Brucella specific IgG1, IgG2a & IgG2b, and IgG3 resulted in no apparent reactivity to RBPT antigen. S19ΔR showed protective index of 1.90 against virulent challenge. S19ΔR being highly attenuated and DIVA compatible may facilitate a platform for developing a safer bovine adulthood vaccine.


Subject(s)
Brucella Vaccine , Brucella abortus , Brucellosis/prevention & control , Mutation , Animals , Brucella Vaccine/genetics , Brucella Vaccine/immunology , Brucella abortus/genetics , Brucella abortus/immunology , Brucella abortus/pathogenicity , Brucellosis/genetics , Brucellosis/immunology , Mice , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology
3.
Arch Virol ; 163(9): 2359-2368, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29736673

ABSTRACT

Canine parvovirus (CPV) is the leading viral cause of enteritis in dogs and occurs mainly in 6- to 8-week-old pups. Rapid diagnosis of CPV under field conditions is now possible due to commercially available immunochromatographic (IC) assays. However, these commercial kits are somewhat expensive because they utilize a minimum of two monoclonal antibodies (mAbs) targeting different epitopes as capture and detector antibodies. Using only a single mAb for both capture and detection purpose may reduce the sensitivity of the assay. In the present study, efforts were made to develop an economical assay that can be utilized for diagnosis of CPV under Indian conditions with a high level of confidence. Rabbit polyclonal antibodies (pAbs) generated against recombinant truncated VP2 proteins of CPV were used as capture antibodies because they can be produced economically, while a commercial anti-CPV mAb was used as the detector antibody. The detection limit of the test strip was 6.6×105 TCID50/ml, and it specifically detected CPV-2, CPV-2a and CPV-2b while displaying no cross-reactivity with other common canine enteric pathogens. The relative sensitivity/specificity of pAb based strip test was 71%/92% and 71%/100% in relation to the hemagglutination test and a commercial IC kit, respectively, with substantial agreement. In addition, two commercially available mAbs targeting different epitopes were also used for development of another IC assay, which showed sensitivity, and specificity of 82%/87% and 90%/98% in relation to the hemagglutination test and commercial kit. Hence, the present strip test based on a combination of mAb and pAb provides an acceptable alternative for onsite and cost-effective diagnosis of CPV infection.


Subject(s)
Dog Diseases/virology , Gold/chemistry , Immunoassay/methods , Metal Nanoparticles/chemistry , Parvoviridae Infections/diagnosis , Parvovirus, Canine/isolation & purification , Animals , Antibodies, Monoclonal/analysis , Antibodies, Viral/blood , Dog Diseases/blood , Dog Diseases/diagnosis , Dogs , Immunoassay/instrumentation , Male , Parvoviridae Infections/blood , Parvoviridae Infections/virology , Parvovirus, Canine/genetics , Parvovirus, Canine/immunology , Rabbits , Sensitivity and Specificity
4.
Prep Biochem Biotechnol ; 47(2): 137-142, 2017 Feb 07.
Article in English | MEDLINE | ID: mdl-27191346

ABSTRACT

Intraphagocytic survival of Salmonella Typhimurium (ST) depends (at least in part) upon its ability to repair oxidant-damaged macromolecules. Met residues either free or in protein bound form are highly susceptible to phagocyte-generated oxidants. Oxidation of Mets leads to Met-SO formation, consequently loss of protein functions that results in cell death. Methionine sulfoxide reductase (Msr) reductively repairs Met-SO to Met in the presence of thioredoxin (trx) and thioredoxin reductase (trxR). Earlier we reported that methionine sulfoxide reductase A (msrA) gene deletion strain of ST suffered oxidative stress.[1] Thioredoxin system of ST comprises of two thioredoxins (trxA and trxC) and one thioredoxin reductase (trxB). Preferred trx utilized in MsrA-mediated repair of Met-SO is not known. In current study, we cloned, expressed, and purified ST TrxA, TrxB, TrxC, and MsrA in recombinant forms. The migration of TrxA, TrxB, TrxC, and MsrA proteins was approximately 10, 36, 16, and 26 kDa on SDS-gels. The nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-linked reductase assays interpreted that MsrA utilized two times more NADPH for the reduction of S-methyl p-tolyl sulfoxide when TrxA was included in the assays as compared to TrxC.


Subject(s)
Methionine Sulfoxide Reductases/metabolism , Methionine/analogs & derivatives , Salmonella typhimurium/enzymology , Thioredoxins/metabolism , Cloning, Molecular , Electrophoresis, Agar Gel , Methionine/metabolism , Methionine Sulfoxide Reductases/genetics , Methionine Sulfoxide Reductases/isolation & purification , Polymerase Chain Reaction , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism
5.
Int J Med Microbiol ; 306(4): 222-30, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27156953

ABSTRACT

The enteric pathogen Salmonella Typhimurium (ST) survives inside the oxidative environment of phagocytic cells. Phagocyte generated oxidants primarily target proteins and modify amino acids in them. These modifications render the targeted proteins functionally inactive. Conversion of Asp to iso-Asp is one of the several known oxidant mediated amino acids modifications. By repairing iso-Asp to Asp, protein-isoaspartyl methyltransferase (PIMT) maintains the activities of proteins and thus helps in cellular survival under oxidative stress. To elucidate the role of PIMT in ST survival under oxidative stress, we have constructed a pimt gene deletion strain (Δpimt strain) of ST. The Δpimt strain grows normally in various culture media in vitro. However, in comparison to wild type ST, the Δpimt strain is found significantly (p<0.001) more susceptible to H2O2 and hypochlorite (HOCl). Further, the Δpimt mutant strain shows hypersusceptibility (p<0.001) to INF-γ stimulated macrophages. This susceptibility is reversed by pharmacological inhibition of reactive oxygen species (ROS) but not reactive nitrogen species (RNS) production. Further, plasmid based complementation enhances the survival of Δpimt mutant strain against oxidants in vitro and also inside the macrophages. In mice model, the LD50 for wild type ST and mutant Δpimt has been 1.73×10(4) and 1.38×10(5), respectively. Further, the mutant strain shows reduced dissemination to spleen and liver in mice. Following infection with a mixture of wild type ST and the Δpimt mutant (co-infection experiment), we recover significantly (p<0.001) less numbers of mutant bacteria from the spleen and liver of mice.


Subject(s)
Microbial Viability , Oxidative Stress , Protein D-Aspartate-L-Isoaspartate Methyltransferase/metabolism , Salmonella typhimurium/enzymology , Salmonella typhimurium/physiology , Stress, Physiological , Animals , Bacterial Load , Female , Gene Deletion , Genetic Complementation Test , Hydrogen Peroxide/toxicity , Hypochlorous Acid/toxicity , Lethal Dose 50 , Liver/microbiology , Macrophages/immunology , Macrophages/microbiology , Mice , Oxidants/toxicity , Protein D-Aspartate-L-Isoaspartate Methyltransferase/genetics , Salmonella Infections, Animal/microbiology , Salmonella Infections, Animal/pathology , Salmonella typhimurium/genetics , Salmonella typhimurium/growth & development , Spleen/microbiology , Virulence
6.
Anal Methods ; 16(29): 5022-5031, 2024 Jul 25.
Article in English | MEDLINE | ID: mdl-38979779

ABSTRACT

In this study, an easily synthesizable Schiff base probe TQSB having a quinoline fluorophore is demonstrated as a fluorescent and colorimetric turn-on sensor for Al3+ ions in a semi-aqueous medium (CH3CN/water; 4 : 1; v/v). Absorption, emission and colorimetric studies clearly indicated that TQSB exhibited a high selectivity toward Al3+, as observed from its excellent binding constant (Kb = 3.8 × 106 M-1) and detection limit (7.0 nM) values. TQSB alone was almost non-fluorescent in nature; however, addition of Al3+ induced intense fluorescence at 414 nm most probably due to combined CHEF (chelation-enhanced fluorescence) and restricted PET effects. The sensing mechanism was established via Job's plot, NMR spectroscopy, ESI-mass spectrometry, and density functional theory (DFT) analyses. Furthermore, to evaluate the applied potential of probe TQSB, its sensing ability was studied in real samples such as soil samples and Al3+-containing Digene gastric tablets as well as on low-cost filter paper strips. Fluorescence microscopy imaging experiments further revealed that TQSB can be used as an effective probe to detect intracellular Al3+ in live cells with no cytotoxicity.


Subject(s)
Aluminum , Fluorescent Dyes , Quinolines , Quinolines/chemistry , Aluminum/analysis , Aluminum/chemistry , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Humans , Microscopy, Fluorescence/methods , Schiff Bases/chemistry , Spectrometry, Fluorescence/methods , Limit of Detection
7.
Chempluschem ; 89(4): e202300721, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38385783

ABSTRACT

An easily synthesizable indole-derived chromofluorogenic probe InNS has been demonstrated for recognition of trivalent metal ions (i. e., Al3+, Ga3+, In3+ and Fe3+). Both UV-Vis and emission spectral studies have been employed to assess the cation sensing ability of InNS in semi-aqueous medium. This probe exhibited a chromogenic response for these metal ions, and the related change was accompanied with the appearance of a new absorption near 376 nm. An obvious color change from pale yellow to dark yellow could also be noticed upon addition of the aforementioned metal ions to the probe's solution. Distinctively from the UV-Vis analysis, the fluorescence behavior of InNS was completely different; it displayed a 'turn-on' fluorescence response for only Al3+ among all the studied cations. The detection limit and the association constant (Ka) for Al3+ were determined to be 12.5 nM and 6.85×106 M-1, respectively. A potential 1 : 1 binding mode of Al3+-InNS has been established based on Job's plot, 1H NMR and DFT analyses. The reversibility experiment was conducted using strongly chelating EDTA ion, and a corresponding logic gate has been devised. In terms of practical applications, the InNS has been utilized to detect Al3+ in human breast carcinoma (MCF-7) cell lines displaying promising 'turn-on' bioimaging experiments.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 310: 123971, 2024 Apr 05.
Article in English | MEDLINE | ID: mdl-38306922

ABSTRACT

A quinoline-derived Schiff base QnSb has been synthesized for fluorescent and colorimetric recognition of Al3+ ions in a semi-aqueous medium. The compound QnSb has been characterized by elemental analysis, FT-IR, 1H/13C NMR, UV-Vis and fluorescence spectral techniques. The crystal structure of the QnSb was confirmed by single crystal X-ray diffraction (SC-XRD) analysis. Notably, almost non-fluorescent QnSb served as a 'turn on' responsive probe for Al3+ by inducing a remarkable fluorescence enhancement at 422 nm when excited at 310 nm. The probe QnSb exhibited high selectivity for Al3+ in CH3CN/H2O (4:1, v/v) solution over several competing metal ions (e.g., Mg2+, Pb2+, Zn2+, Cd2+, Co2+, Cu2+, Ca2+, Ni2+, Fe3+/2+, Cr3+, Mn2+, Sn2+, and Hg2+). The limit of detection (LoD) was computed as low as 15.8 nM which is significantly lower than the permissible limit set by WHO for Al3+ ions in drinking water. A 1:1 binding stoichiometry of complex QnSb-Al3+ was established with the help of Job's plot, ESI-MS, NMR and DFT analyses. Based on its remarkable sensing ability, the probe QnSb was utilized to establish molecular logic gates, and the fluorescence detection of Al3+ could clearly be demonstrated on the filter paper test strips.

9.
Sci Total Environ ; 920: 171043, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38369158

ABSTRACT

Rapid modern industrialization and urbanization have escalated heavy metal pollution, with palladium (Pd2+) raising significant concerns due to its extensive usage in catalysis, hydrogen storage, and electronics, thereby imposing substantial risks on the environment and human health. In this study, we report a highly fluorescent indium nanocubes based chemosensor (InNCs) functionalized with perylene tetracarboxylic acid (PTCA) and 4-(pyridyl)ethenyl benzene (PEB). The InNCs exhibited emission maximum at 415 nm (λex âˆ¼ 350 nm) with robust chemical and photo-stability, and acted as a fluorogenic probe for selective recognition of Pd2+ in aqueous medium. The fluorescence sensing properties of InNCs were thoroughly assessed via different techniques including steady-state absorption, emission and time-resolved emission spectroscopic methods. Among the various competitive analytes, only Pd2+ could induce a significant fluorescence quenching in the probe. This "turn-off" fluorescence sensing demonstrated a remarkably low LoD of ∼65 nM. Notably, with the addition of EDTA, the probe displayed good recyclability upto 4 cycles. The sensory probe was successfully employed as a reusable platform to estimate Pd(II) in different real water and soil samples with considerable accuracy (∼ 5-10 % error). Moreover, the probe exhibited a pH-induced fluorescence transition, indicating its potential to be applied as a pH sensor. The Pd(II) binding and pH-sensing mechanisms have also been elucidated through density functional theory (DFT) calculations.

10.
Chem Phys Lett ; 558: 1-7, 2013 Feb 12.
Article in English | MEDLINE | ID: mdl-24098059

ABSTRACT

Dynamics of the chemical transformation of dicyclopentadiene into cyclopentadiene in a supersonic molecular beam is elucidated using femtosecond time-resolved degenerate pump-probe mass spectrometry. Control of this ultrafast chemical reaction is achieved by using linearly chirped frequency modulated pulses. We show that negatively chirped femtosecond laser pulses enhance the cyclopentadiene photo-product yield by an order of magnitude as compared to that of the unmodulated or the positively chirped pulses. This demonstrates that the phase structure of femtosecond laser pulse plays an important role in determining the outcome of a chemical reaction.

11.
Dalton Trans ; 52(41): 14704-14732, 2023 Oct 24.
Article in English | MEDLINE | ID: mdl-37750386

ABSTRACT

Group 10 metals including Ni, Pd and Pt have been extensively applied in various essential aspects of human social life, material science, industrial manufactures, medicines and biology. The ionic forms of these metals are involved in several biologically important processes due to their strong binding capability towards different biomolecules. However, the mishandling or overuse of such metals has been linked to serious contamination of our ecological system, more specifically in soil and water bodies with acute consequences. Therefore, the detection of group 10 metal ions in biological as well as environmental samples is of huge significance from the human health point of view. Related to this, considerable efforts are underway to develop adequately efficient and facile methods to achieve their selective detection. Optical sensing of metal ions has gained increasing attention of researchers, particularly in the environmental and biological settings. Innovatively designed optical probes (fluorescent or colorimetric) are usually comprised of three basic components: an explicitly tailored receptor unit, a signalling unit and a clearly defined reporter unit. This review deals with the recent progress in the design and fabrication of fluorescent or colorimetric organic sensors for the detection of group 10 metal ions (Ni(II), Pd(II) and Pt(II)), with attention to the general aspects for design of such sensors.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 297: 122697, 2023 Sep 05.
Article in English | MEDLINE | ID: mdl-37071963

ABSTRACT

The development of low-cost earth abundant metal based fluorescent sensors for a rapid and selective nanomolar level detection of Hg2+ is essential due to the increasing world-wide concern of its detrimental effect on humans as well as the environment. Herein, we present a perylene tetracarboxylic acid functionalized copper nanoclusters (CuNCs) based "turn-on" fluorescence probe for highly selective detection of toxic Hg2+ ions. The fabricated CuNCs exhibited high photostability with emission maximum centered at 532 nm (λex = 480 nm). The fluorescence intensity of CuNCs was remarkably enhanced upon the addition of Hg2+ over other competing ions and neutral analytes. Notably, the 'turn-on' fluorescence response exhibits highly sensitive detection limit as low as 15.9 nM (S/N âˆ¼ 3). The time resolved fluorescence spectroscopy suggested the energy transfer between CuNCs and Hg2+ ions following either inhibited fluorescence resonance energy transfer (FRET) or surface modification of CuNCs during Hg2+ sensing. This study offers the systematic design and development of new fluorescent 'turn-on' nanoprobes for rapid and selective recognition of heavy metal ions.

13.
Anal Methods ; 15(44): 6021-6030, 2023 Nov 16.
Article in English | MEDLINE | ID: mdl-37909225

ABSTRACT

An efficient dual functional naphthalene-derived Schiff base NpSb probe has been synthesised and evaluated for its fluorescence and chromogenic response towards metal ions. The NpSb probe was capable of selectively recognising Al3+ and Zn2+ ions when they were excited at the same wavelength in an aqueous organic solvent system. Almost non-fluorescent NpSb displayed a 'turn-on' fluorescence response when treated with Zn2+ (λem = 416 nm) and Al3+ (λem = 469 nm) ions due to the chelation-enhanced fluorescence (CHEF) effect. The limit of detection (LoD) values for Al3+ and Zn2+ have been determined to be 38.0 nM and 43.0 nM, respectively. The binding constants for Al3+ and Zn2+ were found to be 1.18 × 106 M-1 and 3.5 × 105 M-1, respectively. The NpSb also acted as a colorimetric sensor for Al3+ as the colour of the probe's solution turned to pale green from colourless upon Al3+ addition. The binding mechanism between NpSb and Zn2+/Al3+ was supported by the ESI-MS, Job's plot, NMR, and DFT studies. The reversibility experiments were carried out with an F- ion and EDTA with the development of corresponding logic gates. Moreover, NpSb could be applied to detect Al3+ ions in real samples such as tap water, distilled water and soil samples.

14.
Diagnostics (Basel) ; 12(9)2022 Aug 28.
Article in English | MEDLINE | ID: mdl-36140489

ABSTRACT

Human Papilloma Virus 16 (HPV 16) is the well-known causative species responsible for triggering cervical cancer. When left undiagnosed and untreated, this disease leads to life-threatening events among the female populace, especially in developing nations where healthcare resources are already being stretched to their limits. Considering various drawbacks of conventional techniques for diagnosing this highly malignant cancer, it becomes imperative to develop miniaturized biosensing platforms which can aid in early detection of cervical cancer for enhanced patient outcomes. The current study reports on the development of an electrochemical biosensor based on reduced graphene oxide (rGO)/DNA hybrid modified flexible carbon screen-printed electrode (CSPE) for the detection of HPV 16. The carbon-coated SPEs were initially coated with rGO followed by probe DNA (PDNA) immobilization. The nanostructure characterization was performed using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray diffraction (XRD) techniques. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the electrochemical characterization of the nano-biohybrid sensor surface. The optimization studies and analytical performance were assessed using differential pulse voltammetry (DPV), eventually exhibiting a limit of detection (LoD) ~2 pM. The developed sensor was found to be selective solely to HPV 16 target DNA and exhibited a shelf life of 1 month. The performance of the developed flexible sensor further exhibited a promising response in spiked serum samples, which validates its application in future point-of-care scenarios.

15.
Hum Vaccin Immunother ; 18(1): 2035117, 2022 12 31.
Article in English | MEDLINE | ID: mdl-35240914

ABSTRACT

Autoimmune diseases are caused when immune cells act against self-protein. This biological self-non-self-discrimination phenomenon is controlled by a distinct group of lymphocytes known as regulatory T cells (Tregs), which are key inflammatory response regulators and play a pivotal role in immune tolerance and homeostasis. Treg-mediated robust immunosuppression provides self-tolerance and protection against autoimmune diseases. However, once this system fails to operate or poorly operate, it leads to an extreme situation where immune system reacts against self-antigens and destroys host organs, thus causing autoimmune diseases. Tregs can target both innate and adaptive immunity via modulating multiple immune cells such as neutrophils, monocytes, antigen-presenting cells, B cells, and T cells. This review highlights the Treg-mediated immunosuppression, role of several markers and their interplay during Treg development and differentiation, and advances in therapeutic aspects of Treg cells to reduce severity of autoimmunity-related conditions along with emphasizing limitations and challenges of their usages.


Subject(s)
Autoimmune Diseases , T-Lymphocytes, Regulatory , Antigen-Presenting Cells , Autoimmune Diseases/therapy , Autoimmunity , Humans , Immune Tolerance , Immunosuppression Therapy
16.
Phys Chem Chem Phys ; 13(18): 8175-9, 2011 May 14.
Article in English | MEDLINE | ID: mdl-21170442

ABSTRACT

We have measured differential cross sections (DCSs) for the reaction H + D(2) → HD(v' = 2,j' = 0,3,6,9) + D at center-of-mass collision energies E(coll) of 1.25, 1.61, and 1.97 eV using the photoloc technique. The DCSs show a strong dependence on the product rotational quantum number. For the HD(v' = 2,j' = 0) product, the DCS is bimodal but becomes oscillatory as the collision energy is increased. For the other product states, they are dominated by a single peak, which shifts from back to sideward scattering as j' increases, and they are in general less sensitive to changes in the collision energy. The experimental results are compared to quantum mechanical calculations and show good, but not fully quantitative agreement.

17.
Sci Rep ; 11(1): 17214, 2021 08 26.
Article in English | MEDLINE | ID: mdl-34446765

ABSTRACT

Salmonella enterica serovar Gallinarum is a host-restricted bacterial pathogen that causes a serious systemic disease exclusively in birds of all ages. Salmonella enterica serovar Typhimurium is a host-generalist serovar. Dendritic cells (DCs) are key antigen-presenting cells that play an important part in Salmonella host-restriction. We evaluated the differential response of chicken blood monocyte-derived dendritic cells (chMoDCs) exposed to S. Gallinarum or S. Typhimurium. S. Typhimurium was found to be more invasive while S. Gallinarum was more cytotoxic at the early phase of infection and later showed higher resistance against chMoDCs killing. S. Typhimurium promoted relatively higher upregulation of costimulatory and other immune function genes on chMoDCs in comparison to S. Gallinarum during early phase of infection (6 h) as analyzed by real-time PCR. Both Salmonella serovars strongly upregulated the proinflammatory transcripts, however, quantum was relatively narrower with S. Gallinarum. S. Typhimurium-infected chMoDCs promoted relatively higher proliferation of naïve T-cells in comparison to S. Gallinarum as assessed by mixed lymphocyte reaction. Our findings indicated that host restriction of S. Gallinarum to chicken is linked with its profound ability to interfere the DCs function. Present findings provide a valuable roadmap for future work aimed at improved vaccine strategies against this pathogen.


Subject(s)
Dendritic Cells/immunology , Monocytes/immunology , Salmonella typhimurium/immunology , Salmonella/immunology , Animals , B7-1 Antigen/genetics , B7-1 Antigen/immunology , CD40 Antigens/genetics , CD40 Antigens/immunology , Chickens , Cytokines/genetics , Cytokines/immunology , Cytotoxicity, Immunologic/immunology , Dendritic Cells/metabolism , Dendritic Cells/microbiology , Gene Expression/immunology , Host-Pathogen Interactions/immunology , Microbial Viability/immunology , Monocytes/cytology , Salmonella/physiology , Salmonella typhimurium/physiology , Species Specificity , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Toll-Like Receptors/genetics , Toll-Like Receptors/immunology
18.
Vaccines (Basel) ; 9(12)2021 Dec 02.
Article in English | MEDLINE | ID: mdl-34960169

ABSTRACT

Vaccination of cattle and buffaloes with Brucella abortus strain 19 has been the mainstay for control of bovine brucellosis. However, vaccination with S19 suffers major drawbacks in terms of its safety and interference with serodiagnosis of clinical infection. Brucella abortus S19∆per, a perosamine synthetase wbkB gene deletion mutant, overcomes the drawbacks of the S19 vaccine strain. The present study aimed to evaluate the potential of Brucella abortus S19Δper vaccine candidate in the natural host, buffaloes. Safety of S19∆per, for animals use, was assessed in guinea pigs. Protective efficacy of vaccine was assessed in buffaloes by immunizing with normal dose (4 × 1010 colony forming units (CFU)/animal) and reduced dose (2 × 109 CFU/animal) of S19Δper and challenged with virulent strain of B. abortus S544 on 300 days post immunization. Bacterial persistency of S19∆per was assessed in buffalo calves after 42 days of inoculation. Different serological, biochemical and pathological studies were performed to evaluate the S19∆per vaccine. The S19Δper immunized animals showed significantly low levels of anti-lipopolysaccharides (LPS) antibodies. All the immunized animals were protected against challenge infection with B. abortus S544. Sera from the majority of S19Δper immunized buffalo calves showed moderate to weak agglutination to RBPT antigen and thereby, could apparently be differentiated from S19 vaccinated and clinically-infected animals. The S19Δper was more sensitive to buffalo serum complement mediated lysis than its parent strain, S19. Animals culled at 6-weeks-post vaccination showed no gross lesions in organs and there was comparatively lower burden of infection in the lymph nodes of S19Δper immunized animals. With attributes of higher safety, strong protective efficacy and potential of differentiating infected from vaccinated animals (DIVA), S19Δper would be a prospective alternate to conventional S19 vaccines for control of bovine brucellosis as proven in buffaloes.

19.
Chem Phys Lett ; 476(1-3): 31-36, 2009 Jul 07.
Article in English | MEDLINE | ID: mdl-19693264

ABSTRACT

Spectrally resolved femtosecond three-pulse photon echo signal from some metal-octaethyl porphyrins (OEPs) like Zn(II)-OEP, Ni(II)-OEP, Co(II)-OEP is reported. Excited state dynamics is studied by time evolving photon echo spectra for different values of coherence and population relaxation times. Dependence on the spectrally resolved photon echo spectra on varying metal center is analyzed. For all these metallo-porphyrins, the electronic relaxation timescale is found to be limited by our laser pulsewidth of 50 fs whereas the timescale for intramolecular vibrational relaxation, occurring within the Q(00) band was found to be over a picosecond for Co(II)-OEP and Ni(II)-OEP and within a picosecond for Zn(II)-OEP.

20.
Chem Phys ; 360(1-3): 47-52, 2009 Jun 12.
Article in English | MEDLINE | ID: mdl-19696899

ABSTRACT

We present the effect of chirping a femtosecond laser pulse on the fragmentation of n-propyl benzene. An enhancement of an order of magnitude for the relative yields of C3H3+ and C5H5+ in the case of negatively chirped pulses and C6H5+ in the case of positively chirped pulses with respect to the transform-limited pulse indicates that in some fragmentation channel, coherence of the laser field plays an important role. For the relative yield of all other heavier fragment ions, resulting from the interaction of the intense laser field with the molecule, there is no such enhancement effect with the sign of chirp, within experimental errors. The importance of the laser phase is further reinforced through a direct comparison of the fragmentation results with the second harmonic of the chirped laser pulse with identical bandwidth.

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