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1.
Article in English | MEDLINE | ID: mdl-38193284

ABSTRACT

The sensitivity and fabrication process of the detection platform are important for developing viral disease diagnosis. Recently, the outbreak of SARS-CoV-2 compelled us to develop a new detection platform to control such diseases in the future. We present an electrochemical-based assay that employs the unique properties of gold nanoparticles (AuNPs) deposited on 3D carboxyl-functionalized poly(3,4-ethylenedioxythiophene) (PEDOTAc) nanorods for specific and sensitive detection of SARS-CoV-2 spike protein (S1). The 3D-shaped PEDOTAc nanorods offer an ample surface area for receptor immobilization grown on indium-tin oxide surfaces through transfer-printing technology. Characterization via electrochemical, fluorescence, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques confirmed the structural and morphological properties of the AuNPs-decorated PEDOTAc. In contrast to antibody-based assays, our platform employs ACE2 receptors for spike protein binding. Differential pulse voltammetry records current responses, showing linear sensitivity from 100 ng to 10 pg/mL of S1. In addition, the SARS-CoV-2 assay (CoVPNs) also exhibited excellent selectivity against nonspecific target proteins (H9N2, IL-6, and Escherichia coli). Furthermore, the developed surface maintained good stability for up to 7 consecutive days without losing performance. The results provide new insight into effective 3D conductive nanostructure formation, which is promising in the development of versatile sensory devices.

2.
Front Chem ; 10: 955260, 2022.
Article in English | MEDLINE | ID: mdl-35991598

ABSTRACT

The challenge of infectious diseases remains a critical concern to the global public health. Recently, it is common to encounter touch-screen electronic devices everywhere to access services. The surface of such devices may easily get contaminated by an infected person, which leads to transmission of infectious diseases between individuals. Moreover, the challenge is complicated by surgical infections from implantable biomedical devices. Such problems can be minimized by the use of long-term active antimicrobial surface coatings. We present herein the preparation of novel electroactive antimicrobial surface coatings through the covalent attachment of the biguanide moiety onto 3,4-ethylenedioxythiophene (EDOT). The biguanide-functionalized EDOT (EDOT-BG) was thus electropolymerized on different substrates to give the corresponding poly(EDOT-BG) polymer. The poly(EDOT-BG) polymer showed an excellent bactericidal efficiency (∼92% bacterial death) and excellent biocompatibility with mammalian cells. Furthermore, the antimicrobial EDOT-BG was electro-copolymerized with antifouling tetra ethylene glycol functionalized-EDOT (EDOT-EG4) to give a multifunctional poly(EDOT-EG4-co-EDOT-BG) copolymer. The poly(EDOT-EG4-co-EDOT-BG) copolymer showed excellent resistance to protein adsorption and mammalian/bacterial cell binding without losing its bactericidal efficiency. These novel materials can be applied to domestic and bioelectronic devices to minimize infectious diseases.

3.
ACS Appl Mater Interfaces ; 14(35): 40322-40330, 2022 Sep 07.
Article in English | MEDLINE | ID: mdl-35994422

ABSTRACT

Developing a smart responsive surface for on-demand delivery of organic, inorganic, and biological cargo in vitro cellular uptake is always in constant demand. Herein, we present carbon quantum dot (CQD)-loaded (poly(N-isopropylacrylamide) (PNIPAAm)/poly(methyl methacrylate (PMMA)) blend nanofiber sheets having a thermoresponsive nature. As a model cargo, fluorescent CQDs are used for the demonstration of the on-demand delivery mechanism. In addition, a thermoresponsive nature is produced by the PNIPAAm polymer in the nanofiber matrix while the PMMA polymer provides extra stability and firmness to the nanofibers against the sudden dissolution of the nanofibers in aqueous media. The synthesis of CQDs and their loading into a blend nanofiber matrix are confirmed using fluorescence spectrophotometry, transmission electron microscopy, and fluorescence microscopy. The morphologies and diameters of the nanofibers are analyzed by scanning electron microscopy. Burst effect analysis proves that 30% (w/w) PNIPAAm-containing nanofibers possess the highest stability with the least dissolution in aqueous media. Thermoresponsiveness of the nanofibers is further confirmed through water contact angle measurements. Quantitative fluorescence results show that more than 80% of loaded CQDs can be released upon thermal stimulation. The fluorescence micrographs reveal that the blend nanofiber sheets can effectively improve the cellular uptake of CQDs by simply increasing the local concentrations via applying thermal stimulation as the released mechanism.


Subject(s)
Nanofibers , Quantum Dots , Carbon , Polymers , Polymethyl Methacrylate
4.
Diagnostics (Basel) ; 12(6)2022 Jun 13.
Article in English | MEDLINE | ID: mdl-35741265

ABSTRACT

Leptospirosis is a spirochaetal infection that possesses a broad host range affecting almost all mammals. In the present study, the microscopic agglutination test (MAT) was compared with recombinant LigA/B antigen-based point-of-care diagnostics such as the in-house IgM dot ELISA dipstick test (IgM- DEDT) and the latex agglutination test (LAT) for the serodiagnosis of human leptospirosis. The comparison of the MAT with these two point-of-care diagnostics was performed using the MAT as the gold standard test and using Bayesian latent class modelling (BLCM), which considers all diagnostic tests as imperfect. The N-terminal conserved region of the LigA/B protein spanning the first to fifth big tandem repeat domains (rLigA/BCon1-5) was employed as a serodiagnostic marker in both of the bedside assays. A total of 340 serum samples collected from humans involved in high risk occupations were screened using the MAT, IgM DEDT and LAT. During the early phase of leptospirosis, BLCM analysis showed that the IgM DEDT and LAT had similar sensitivities (99.6 (96.0-100)) and (99.5 (95.2-100)), respectively, while the single acute phase MAT had the lowest sensitivity (83.3 (72.8-91.3)). Both the IgM DEDT and the LAT may be superior to the single acute phase MAT in terms of sensitivity during the early phase of infection and may be suitable for the early diagnosis of leptospirosis. However, BLCM analysis revealed that the use of both acute and convalescent samples substantially increased the sensitivity of the final MAT (98.2% (93.0-99.8%)) as a test to diagnose human leptospirosis. Both the IgM DEDT and LAT can be employed as bedside spot tests in remote locations where the MAT is not easily accessible.

5.
Anim Biotechnol ; 33(6): 1025-1034, 2022 Nov.
Article in English | MEDLINE | ID: mdl-33427030

ABSTRACT

A microcapillary-based loop-mediated isothermal amplification (µcLAMP) has been described for specific detection of infectious reproductive pathogens in semen samples of cattle without sophisticated instrumentation. Brucella abortus, Leptospira interrogans serovar Pomona and bovine herpesvirus 1 (BoHV-1) cultures were mixed in bovine semen samples. The µcLAMP assay is portable, user-friendly, cost-effective, and suitable to be performed as a POC diagnostic test. We have demonstrated high sensitivity and specificity of µcLAMP for detection of Brucella, Leptospira, and BoHV-1 in bovine semen samples comparable to PCR and qPCR assays. Thus, µcLAMP would be a promising field-based test for monitoring various infectious pathogens in biological samples.HighlightsDetect infectious organism in bovines semenReduction in carryover contamination is an important attribute, which may reduce the false-positive reaction.µcLAMP is a miniaturized form, which could be performed with a minimum volume of reagents.The µcLAMP assay is portable, user-friendly, and suitable to be performed as a POC diagnostic test.


Subject(s)
Herpesvirus 1, Bovine , Semen , Cattle , Animals , Nucleic Acid Amplification Techniques , Herpesvirus 1, Bovine/genetics , Real-Time Polymerase Chain Reaction/veterinary , Sensitivity and Specificity
6.
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.

7.
Inquiry ; 58: 469580211028174, 2021.
Article in English | MEDLINE | ID: mdl-34167365

ABSTRACT

Healthcare organizations are setting new targets of sustainable practices to improve their financial performance without depleting social and natural capital. Maintaining a sustainable, resilient, and durable healthcare system facilitate economies to achieve sustainable competitiveness. Thus, it is important to address and fill the knowledge gap by identifying factors that improve a firm's sustainability. Drawing on technological knowledge spillover theory, this study investigates the effect of FinTech development on the sustainable performance of healthcare firms using panel data comprised of 11 Asia-Pacific countries. By applying the 2-step GMM technique, we find a robust estimate that digital financial technologies improve the sustainable performance of the firms. Contrary to the substitution effect, our results further indicate that financial institutions are collaborating with FinTechs to facilitate financing at the individual and firm-level. We also find that financial and ICT development positively moderates the relationship between FinTech development and sustainable performance.


Subject(s)
Health Care Sector , Income , Humans
8.
ACS Appl Bio Mater ; 4(11): 7893-7902, 2021 11 15.
Article in English | MEDLINE | ID: mdl-35006770

ABSTRACT

Infectious diseases triggered by bacteria cause a severe risk to human health. To counter this issue, surfaces coated with antibacterial materials have been widely used in daily life to kill these bacteria. The substrates enabled with a hybrid kill and release strategy can be employed not only to kill the bacteria but also to wash them using external stimuli (temperature, pH, etc.). Utilizing this concept, we develop thermoresponsive antibacterial-cellulose papers to exhibit hybrid kill and release properties. Thermoresponsive copolymers [p(NIPAAm-co-AEMA)] are grafted on cellulose papers using a surface-initiated atom transfer radical polymerization approach for bacterial debris release. Later for antibacterial properties, silver nanoparticles (AgNPs) are immobilized on thermoresponsive copolymer-grafted cellulose papers using electrostatic interactions. We confirm the thermoresponsive copolymer grafting and AgNP coating by attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Thermoresponsiveness and reusability of the modified cellulose papers are confirmed through water contact angle measurements. The interaction potency between AgNPs and modified cellulose is validated by inductively coupled plasma atomic emission spectroscopy analysis. Gram-negative bacteria Escherichia coli (E. coli DH5-α) is used to demonstrate antibacterial hybrid kill and release performance. Agar-diffusion testing demonstrates the antibacterial nature of the modified cellulose papers. The fluorescence micrograph reveals that modified cellulose papers can effectively release almost all the dead bacterial debris from their surfaces after thermal stimulus wash. The modified cellulose paper surfaces are expected to have wide applications in the field of exploring more antibacterial and smart surfaces.


Subject(s)
Escherichia coli , Metal Nanoparticles , Anti-Bacterial Agents/pharmacology , Bacteria , Cellulose/pharmacology , Humans , Metal Nanoparticles/chemistry , Polymerization , Polymers/chemistry , Silver/pharmacology
9.
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
10.
Talanta ; 188: 325-331, 2018 Oct 01.
Article in English | MEDLINE | ID: mdl-30029383

ABSTRACT

Owing to their unique physical and chemical properties like stability, non-toxic, biocompatibility and feasible to modification with various biomolecules, gold nanoparticle has become a versatile nanomaterial in the field of therapeutic, diagnostic and analytical studies. Various surface plasmon resonance based pathogen detection systems, relying on change in colour, have been proposed. However, all the approaches developed so far were designed for the detection of a single pathogen. In the present study, we have designed a new colorimetric approach based on distant-dependent properties of gold nanoparticle for the detection of multiple targets. A modified multiplex asymmetric PCR in which a universal primer amplifies the multiple targets with the same efficiency was performed. The Limit of detection (LOD) of the designed visual assay is 10 pg of Brucella and Leptospira target DNA and 100 pg of Bovine herpes virus-1 (BoHV-1) target DNA. LOD of 0.5 pg, 0.7 pg and 3.8 pg for Brucella, Leptospira and BoHV-1 respectively was obtained spectrophotometrically. A study on dark field microscopy as a qualitative supporting detection system has also been presented in this study. The designed assay has advantages over earlier reports in terms of multiple organisms detection, specificity and sensitivity of the test.


Subject(s)
Biosensing Techniques/methods , DNA, Single-Stranded/analysis , Gold/chemistry , Metal Nanoparticles/chemistry , Molecular Probes/genetics , Brucella/genetics , Colorimetry/methods , DNA, Single-Stranded/genetics , Herpesvirus 1, Bovine/genetics , Leptospira/genetics , Limit of Detection , Microscopy/methods , Nucleic Acid Hybridization , Polymerase Chain Reaction
11.
ACS Sens ; 3(2): 403-409, 2018 02 23.
Article in English | MEDLINE | ID: mdl-29322764

ABSTRACT

The health and well-being of cattle is an important issue in maintaining and increasing global agricultural output. In dairy production within low and middle income countries (LMICs), there is a significant biosensing challenge in detecting sexually transmitted infection (STI) pathogens during animal husbandry, due in part to difficulties associated with the limited infrastructure for veterinary medicine. Here we demonstrate low-cost, multiplexed, and sample-to-answer paper-origami tests for the detection of three bovine infectious reproductive diseases in semen samples, collected at a test site in rural India. Pathogen DNA from one viral pathogen, bovine herpes virus-1 (BoHV-1), and two bacteria (Brucella and Leptospira) was extracted, amplified (using loop-mediated isothermal amplification, LAMP), and detected fluorescently, enabling <1 pg (∼ from 115 to 274 copies per reaction) of target genomic DNA to be measured. Data was collected as a fluorescence signal either visually, using a low-cost hand-held torch, or digitally with a mobile-phone camera. Limits of detection and sensitivities of the paper-origami device for the three pathogens were also evaluated using pathogen-inoculated semen samples and were as few as 50 Leptospira organisms, 50 CFU Brucella, and 1 TCID50 BoHV-1. Semen samples from elite bulls at a germplasm center were also tested in double-blind tests, as a demonstrator for a low-cost, user-friendly point-of-care sensing platform, for in-the-field resource-limited regions. The sensors showed excellent levels of sensitivity and specificity, and for the first time a demonstrated ability of the application of paper microfluidics devices for the diagnosis multiple infectious diseases from semen samples.


Subject(s)
Cattle Diseases , DNA, Bacterial/chemistry , DNA, Viral/chemistry , Microfluidics , Molecular Diagnostic Techniques/veterinary , Semen , Animals , Brucella abortus/isolation & purification , Brucellosis, Bovine/microbiology , Cattle , Cattle Diseases/microbiology , Cattle Diseases/virology , Herpesviridae Infections/veterinary , Herpesviridae Infections/virology , Herpesvirus 1, Bovine/isolation & purification , Leptospira/isolation & purification , Leptospirosis/microbiology , Leptospirosis/veterinary , Limit of Detection , Microfluidics/instrumentation , Microfluidics/methods , Molecular Diagnostic Techniques/instrumentation , Molecular Diagnostic Techniques/methods , Paper , Semen/microbiology , Semen/virology
12.
Mol Cell Probes ; 36: 29-35, 2017 12.
Article in English | MEDLINE | ID: mdl-28803792

ABSTRACT

Leptospirosis is considered to be the most widespread zoonotic disease caused by pathogenic species of Leptospira. The present study reports a novel set of primers targeting LigB gene for visual detection of pathogenic Leptospira in urine samples through Loop-mediated isothermal amplification (LAMP). The results were recorded by using Hydroxyl napthol blue (HNB), SYBR GREEN I and calcein. Analytical sensitivity of LAMP was as few as 10 leptospiral organisms in spiked urine samples from cattle and dog. LigB gene based LAMP, termed as LigB-LAMP, was found 10 times more sensitive than conventional PCR. The diagnostic specificity of LAMP was 100% when compared to SYBR green qPCR for detection of Leptospira in urine samples. Though qPCR was found more sensitive, the rapidity and simplicity in setting LAMP test followed by visual detection of Leptospira infection in clinical samples makes LigB-LAMP an alternative and favourable diagnostic tool in resource poor setting.


Subject(s)
Antigens, Bacterial/urine , Coloring Agents/metabolism , Leptospira/isolation & purification , Nucleic Acid Amplification Techniques/methods , Animals , Base Sequence , Cattle , Dogs , Limit of Detection , Sensitivity and Specificity
13.
PLoS One ; 12(7): e0180919, 2017.
Article in English | MEDLINE | ID: mdl-28719613

ABSTRACT

Brucellosis is a bacterial disease, which, although affecting cattle primarily, has been associated with human infections, making its detection an important challenge. The existing gold standard diagnosis relies on the culture of bacteria which is a lengthy and costly process, taking up to 45 days. New technologies based on molecular diagnosis have been proposed, either through dip-stick, immunological assays, which have limited specificity, or using nucleic acid tests, which enable to identify the pathogen, but are impractical for use in the field, where most of the reservoir cases are located. Here we demonstrate a new test based on hybridization assays with metal nanoparticles, which, upon detection of a specific pathogen-derived DNA sequence, yield a visual colour change. We characterise the components used in the assay with a range of analytical techniques and show sensitivities down to 1000 cfu/ml for the detection of Brucella. Finally, we demonstrate that the assay works in a range of bovine samples including semen, milk and urine, opening up the potential for its use in the field, in low-resource settings.


Subject(s)
Biosensing Techniques/methods , Brucella/isolation & purification , DNA Probes/chemistry , Gold/chemistry , Metal Nanoparticles/chemistry , Animals , Cattle , Limit of Detection , Milk , Nucleic Acid Hybridization , Reproducibility of Results
14.
Pak J Pharm Sci ; 30(3): 891-895, 2017 May.
Article in English | MEDLINE | ID: mdl-28653935

ABSTRACT

This study evaluated the impact of pH (7.4 and 6.5), bovine serum albumin (BSA), and human serum albumin (HSA) on Curcumin activity against 2 reference, 1 clinical, and 10 environmental strains of Staphylococcus aureus (S. aureus). Minimal inhibitory concentrations (MICs) of Curcumin against S. aureus were statistically indifferent (p>0.05) at pH7.4 and pH6.5. Activity of Curcumin against S. aureus was reduced by two folds in the presence of 1.25-5% BSA/HSA.


Subject(s)
Curcumin/pharmacology , Animals , Anti-Bacterial Agents/pharmacology , Cattle , Humans , Hydrogen-Ion Concentration , In Vitro Techniques , Microbial Sensitivity Tests , Serum Albumin/chemistry , Staphylococcus aureus/drug effects
15.
Pak J Pharm Sci ; 29(6): 2119-2124, 2016 Nov.
Article in English | MEDLINE | ID: mdl-28375134

ABSTRACT

Peptides derived from HIV-1 transmembrane proteins have been extensively studied for antimicrobial activities, and they are known as antimicrobial peptides (AMPs). These AMPs have also been reported to potently combat the drug-resistant microbes. In this study, we demonstrated that peptide #6383 originated from HIV-1 MN strain membrane-spanning domain of gp41 was active (2-log reductions) at 100ßg/mL (56.5ßM) against methicillin-resistant Staphylococcus aureus (MRSA) in 10% and 50% human plasma-supplemented phosphate buffered saline (PBS). The activity was further enhanced (3-log reductions) in the presence of 5% human serum albumin (HSA) alone. All bactericidal activities were achieved within 6 hours. At 100µg/mL, the peptide showed only 13% toxicity against human erythrocytes. This peptide can serve as an attractive template for a design of a novel peptide antibiotic against drug-resistant bacteria. By sequence-specific engineering or modifications, we anticipated that the bactericidal activity and the reduced toxicity against human erythrocytes will be improved.


Subject(s)
Anti-Bacterial Agents/pharmacology , HIV Envelope Protein gp41/pharmacology , HIV-1/chemistry , Methicillin-Resistant Staphylococcus aureus/drug effects , Peptide Fragments/pharmacology , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/toxicity , Dose-Response Relationship, Drug , Erythrocytes/drug effects , HIV Envelope Protein gp41/isolation & purification , Hemolysis/drug effects , Humans , Kinetics , Methicillin-Resistant Staphylococcus aureus/growth & development , Microbial Viability/drug effects , Peptide Fragments/isolation & purification , Peptide Fragments/toxicity
16.
Pak J Pharm Sci ; 28(6): 2109-14, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26639480

ABSTRACT

This study evaluated the synergistic antibacterial activity of Curcumin with 8 different antibiotic groups. Two reference, one clinical and ten environmental strains of Staphylococcus aureus (S. aureus) were tested. Disc diffusion assay with 25 µg/mL Curcumin demonstrated synergism in combination with a majority of tested antibiotics against S. aureus. However, checkerboard micro dilution assay only showed synergism, fractional inhibitory concentration index (FICI) <0.5 in three antibiotics i.e. Gentamicin, Amikacin, and Ciprofloxacin. Other antibiotics showed indifferent interactions but no antagonism was observed. In time-kill curve, appreciable reduction of bacterial cells was also observed in combination therapy (Curcumin + antibiotics) compared to monotherapy (Curcumin or antibiotic(s) alone). The antibiotics with higher synergistic interaction with Curcumin are arranged in a decreasing order: Amikacin > Gentamicin > Ciprofloxacin.


Subject(s)
Anti-Bacterial Agents/pharmacology , Curcumin , Plant Extracts/pharmacology , Staphylococcus aureus/drug effects , Amikacin/pharmacology , Anti-Bacterial Agents/isolation & purification , Ciprofloxacin/pharmacology , Curcumin/chemistry , Disk Diffusion Antimicrobial Tests , Dose-Response Relationship, Drug , Drug Synergism , Gentamicins/pharmacology , Phytotherapy , Plant Extracts/isolation & purification , Plants, Medicinal , Staphylococcus aureus/growth & development , Time Factors
17.
Int J Mol Sci ; 15(9): 15044-60, 2014 Aug 26.
Article in English | MEDLINE | ID: mdl-25162825

ABSTRACT

Mesenchymal stem cells (MSCs) hold tremendous potential for therapeutic use in stem cell-based gene therapy. Ex vivo genetic modification of MSCs with beneficial genes of interest is a prerequisite for successful use of stem cell-based therapeutic applications. However, genetic manipulation of MSCs is challenging because they are resistant to commonly used methods to introduce exogenous DNA or RNA. Herein we compared the effectiveness of several techniques (classic calcium phosphate precipitation, cationic polymer, and standard electroporation) with that of microporation technology to introduce the plasmid encoding for angiopoietin-1 (ANGPT-1) and enhanced green fluorescent protein (eGFP) into human adipose-derived MSCs (hAD-MSCs). The microporation technique had a higher transfection efficiency, with up to 50% of the viable hAD-MSCs being transfected, compared to the other transfection techniques, for which less than 1% of cells were positive for eGFP expression following transfection. The capability of cells to proliferate and differentiate into three major lineages (chondrocytes, adipocytes, and osteocytes) was found to be independent of the technique used for transfection. These results show that the microporation technique is superior to the others in terms of its ability to transfect hAD-MSCs without affecting their proliferation and differentiation capabilities. Therefore, this study provides a foundation for the selection of techniques when using ex vivo gene manipulation for cell-based gene therapy with MSCs as the vehicle for gene delivery.


Subject(s)
Electroporation/methods , Mesenchymal Stem Cells/metabolism , Adipose Tissue/cytology , Angiopoietin-1/genetics , Angiopoietin-1/metabolism , Cell Differentiation , Cell Line , Cell Proliferation , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Humans , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/physiology
18.
Microb Pathog ; 48(2): 85-90, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19900531

ABSTRACT

Vibrio cholerae is a Gram-negative bacterium that causes diarrheal disease. V. cholerae O1 and O139 serogroups are toxigenic and are known to cause epidemic cholera. These serogroups produce cholera toxin and other accessory toxins such as accessory cholera enterotoxin, zonula occludens toxin, and multifunctional, autoprocessing repeat in toxin (MARTX). In the present study, we incorporated mutated rtxA and rtxC genes that encode MARTX toxin into the existing aminolevulinic acid (ALA) auxotrophic vaccine candidate VCUSM2 of V. cholerae O139 serogroup. The rtxC mutant was named VCUSM9 and the rtxC/rtxA mutant was named VCUSM10. VCUSM9 and VCUSM10 were able to colonize intestinal cells well, compared with the parent vaccine strain, and produced no fluid accumulation in a rabbit ileal loop model. Cell rounding and western blotting assays indicated that mutation of the rtxC gene alone (VCUSM9 strain) did not abolish MARTX toxicity. However mutation of both the rtxA and rtxC genes (VCUSM10) completely abolished MARTX toxicity. Thus we have produced a new, less reactogenic, auxotrophic rtxC/rtxA mutated vaccine candidate against O139 V. cholerae.


Subject(s)
Acyltransferases/genetics , Bacterial Proteins/genetics , Bacterial Toxins/genetics , Cholera Vaccines , Vibrio cholerae O139/genetics , Animals , Bacterial Toxins/toxicity , Cell Line, Tumor , Gene Deletion , Genes, Bacterial , Humans , Intestines/microbiology , Mice , Mutagenesis, Insertional , Rabbits , Serotyping , Vibrio cholerae O139/growth & development , Vibrio cholerae O139/metabolism , Vibrio cholerae O139/pathogenicity , Virulence Factors/genetics
19.
Vaccine ; 24(18): 3750-61, 2006 May 01.
Article in English | MEDLINE | ID: mdl-16102875

ABSTRACT

In this paper, we describe the development of VCUSM2, a live metabolic auxotroph of Vibrio cholerae O139. Auxotrophy was achieved by mutating a house keeping gene, hemA, that encodes for glutamyl-tRNA reductase, an important enzyme in the C5 pathway for delta-aminolevulenic acid (ALA) biosynthesis, which renders this strain dependent on exogenous ALA for survival. Experiments using the infant mouse and adult rabbit models show that VCUSM2 is a good colonizer of the small intestine and elicits greater than a four-fold rise in vibriocidal antibodies in vaccinated rabbits. Rabbits vaccinated with VCUSM2 were fully protected against subsequent challenge with 1 x 10(11) CFU of the virulent wild type (WT) strain. Experiments using ligated ileal loops of rabbits show that VCUSM2 is 2.5-fold less toxic at the dose of 1 x 10(6) CFU compared to the WT strain. Shedding of VCUSM2 in rabbits were found to occur for no longer than 4 days and its maximum survival rate in environmental waters is 8 days compared to the greater than 20 days for the WT strain. VCUSM2 is thus a potential vaccine candidate against infection by V. cholerae O139.


Subject(s)
Aldehyde Oxidoreductases/genetics , Cholera Vaccines/immunology , Cholera/prevention & control , Vaccines, Attenuated/immunology , Vibrio cholerae O139/immunology , Animals , Antibodies, Bacterial/blood , Cholera Toxin/immunology , Cholera Vaccines/administration & dosage , Cholera Vaccines/genetics , Colony Count, Microbial , Disease Models, Animal , Immunoglobulin A/blood , Immunoglobulin G/blood , Intestine, Small/microbiology , Lipopolysaccharides/immunology , Mice , Mice, Inbred BALB C , Mutation , Rabbits , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/genetics , Vibrio cholerae O139/genetics , Vibrio cholerae O139/growth & development , Virulence
20.
Biol Pharm Bull ; 25(3): 386-9, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11913540

ABSTRACT

In this study the anti-proliferative effect of curcumin (curcuma longa) that is the active ingredient of ground dried rhizome has been studied against three local and three reference leishmanial strains, Leishmania major, Leishmania tropica and Leishmania infantum (Pakistani isolate). Curcumin has shown an average IC50 of 5.3 microM against promastigotes of various leishmanial strains which is much lower as compared with pentamidine that is one of the basic treatments against leishmaniasis. The main draw back attributed to these assays performed on promastigotes is the heterogeneity of results compared with those obtained with intracellular amastigotes or with in vivo effect. We also tested activity of curcumin against axenic amastigote like cells (AALC) of L. major strain (MHOM/PK/88/DESTO). Curcumin proves to be far more potent then pentamidine against AALC which further strengthens the fact about its leishmaniacidal activity.


Subject(s)
Antiprotozoal Agents/pharmacology , Curcumin/pharmacology , Leishmania/drug effects , Animals
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