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Now showing 1 - 5 of 5
  • PublicationOpen Access
    Draft Genome Sequence of the Marine Bioluminescent Bacterium Aliivibrio fischeri ATCC 7744
    (2022-04-01T00:00:00Z) Low, Eric Kat Jun; Goh, Amos Eng Liang; Logis, Joko; Lee, Siew Wei; FATIMA, AYESHA; Yap, Wai Sum; Lim, Crystale Siew Ying; FATIMA, AYESHA
    The Gram-negative marine bioluminescent bacterium Aliivibrio fischeri is commonly used as a bioreporter in drug inhibition studies. Its bioluminescence is regulated by the gene expression of the luxl-luxR quorum-sensing system. Here, we report the draft genome sequence of A. fischeri ATCC 7744, including identification of the putative lux operon.
  • PublicationOpen Access
    Isolation and Characterization of Werneria Chromene and Dihydroxyacidissimol from Burkillanthus malaccensis (Ridl.) Swingle
    (2022-06-01T00:00:00Z) Zulkipli, Masyitah; Mahbub, Nuzum; FATIMA, AYESHA; Wan-Lin, Stefanie Lim; Khoo, Teng-Jin; Mahboob, Tooba; Rajagopal, Mogana; Samudi, Chandramathi; Kathirvalu, Gheetanjali; Abdullah, Nor Hayati; Pinho, Ana Rita; Oliveira, Sonia M. R.; Pereira, Maria de Lourdes; Rahmatullah, Mohammed; Hasan, Anamul; Paul, Alok K.; Butler, Mark S.; Nawaz, Muhammad; Wilairatana, Polrat; Nissapatorn, Veeranoot; Wiart, Christophe; FATIMA, AYESHA
    The secondary metabolites of endemic plants from the Rutaceae family, such as Burkillanthus malaccensis (Ridl.) Swingle from the rainforest of Malaysia, has not been studied. Burkillanthus malaccensis (Ridl.) Swingle may produce antibacterial and antibiotic-potentiating secondary metabolites. Hexane, chloroform, and methanol extracts of leaves, bark, wood, pericarps, and endocarps were tested against bacteria by broth microdilution assay and their antibiotic-potentiating activities. Chromatographic separations of hexane extracts of seeds were conducted to investigate effective phytochemicals and their antibacterial activities. Molecular docking studies of werneria chromene and dihydroxyacidissiminol against SARS-CoV-2 virus infection were conducted using AutoDock Vina. The methanol extract of bark inhibited the growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa with the minimum inhibitory concentration of 250, 500, and 250 mu g/mL, respectively. The chloroform extract of endocarps potentiated the activity of imipenem against imipenem-resistant Acinetobacter baumannii. The hexane extract of seeds increased the sensitivity of P. aeruginosa against ciprofloxacin and levofloxacin. The hexane extract of seeds and chloroform extract of endocarps were chromatographed, yielding werneria chromene and dihydroxyacidissiminol. Werneria chromene was bacteriostatic for P. aeruginosa and P. putida, with MIC/MBC values of 1000 > 1000 mu g/mL. Dihydroxyacidissiminol showed the predicted binding energies of -8.1, -7.6, -7.0, and -7.5 kcal/mol with cathepsin L, nsp13 helicase, SARS-CoV-2 main protease, and SARS-CoV-2 spike protein receptor-binding domain S-RBD. Burkillanthus malaccensis (Ridl.) Swingle can be a potential source of natural products with antibiotic-potentiating activity and that are anti-SARS-CoV-2.
  • PublicationOpen Access
    Evaluation of Catechin Synergistic and Antibacterial Efficacy on Biofilm Formation and acrA Gene Expression of Uropathogenic E. coli Clinical Isolates
    (2022-09-01T00:00:00Z) Jubair, Najwan; Mogana, R.; FATIMA, AYESHA; Mahdi, Yasir K.; Abdullah, Nor Hayati; FATIMA, AYESHA
    Uropathogenic Escherichia coli has a propensity to build biofilms to resist host defense and antimicrobials. Recurrent urinary tract infection (UTI) caused by multidrug-resistant, biofilm-forming E. coli is a significant public health problem. Consequently, searching for alternative medications has become essential. This study was undertaken to investigate the antibacterial, synergistic, and antibiofilm activities of catechin isolated from Canarium patentinervium Miq. against three E. coli ATCC reference strains (ATCC 25922, ATCC 8739, and ATCC 43895) and fifteen clinical isolates collected from UTI patients in Baghdad, Iraq. In addition, the expression of the biofilm-related gene, acrA, was evaluated with and without catechin treatment. Molecular docking was performed to evaluate the binding mode between catechin and the target protein using Autodock Vina 1.2.0 software. Catechin demonstrated significant bactericidal activity with a minimum inhibitory concentration (MIC) range of 1-2 mg/mL and a minimum bactericidal concentration (MBC) range of 2-4 mg/mL and strong synergy when combined with tetracycline at the MBC value. In addition, catechin substantially reduced E. coli biofilm by downregulating the acrA gene with a reduction percent >= 60%. In silico analysis revealed that catechin bound with high affinity ( increment G = -8.2 kcal/mol) to AcrB protein (PDB-ID: 5ENT), one of the key AcrAB-TolC efflux pump proteins suggesting that catechin might inhibit the acrA gene indirectly by docking at the active site of AcrB protein.
  • PublicationOpen Access
    Computational design and characterization of a multiepitope vaccine against carbapenemase-producing Klebsiella pneumoniae strains, derived from antigens identified through reverse vaccinology
    (2022-01-01T00:00:00Z) Cuscino, Nicola; Fatima, Ayesha; Di Pilato, Vincenzo; Bulati, Matteo; Alfano, Caterina; Monaca, Elisa; Di Mento, Giuseppina; Di Carlo, Daniele; Cardinale, Francesca; Monaco, Francesco; Rossolini, Gian Maria; KHAN, MOHAMMAD ASİF; Conaldi, Pier Giulio; Douradinha, Bruno; FATIMA, AYESHA; KHAN, MOHAMMAD ASİF
    Klebsiella pneumoniae is a Gram-negative pathogen of clinical relevance, which can provoke serious urinary and blood infections and pneumonia. This bacterium is a major public health threat due to its resistance to several antibiotic classes. Using a reverse vaccinology approach, 7 potential antigens were identified, of which 4 were present in most of the sequences of Italian carbapenem-resistant K. pneumoniae clinical isolates. Bioinformatics tools demonstrated the antigenic potential of these bacterial proteins and allowed for the identification of T and B cell epitopes. This led to a rational design and in silico characterization of a multiepitope vaccine against carbapenem-resistant K. pneumoniae strains. As adjuvant, the mycobacterial heparin-binding hemagglutinin adhesin (HBHA), which is a Toll-like receptor 4 (TLR-4) agonist, was included, to increase the immunogenicity of the construct. The multiepitope vaccine candidate was analyzed by bioinformatics tools to assess its antigenicity, solubility, allergenicity, toxicity, physical and chemical parameters, and secondary and tertiary structures. Molecular docking binding energies to TLR-2 and TLR-4, two important innate immunity receptors involved in the immune response against K. pneumoniae infections, and molecular dynamics simulations of such complexes supported active interactions. A codon optimized multiepitope sequence cloning strategy is proposed, for production of recombinant vaccine in classical bacterial vectors. Finally, a 3 dose-immunization simulation with the multiepitope construct induced both cellular and humoral immune responses. These results suggest that this multiepitope construct has potential as a vaccination strategy against carbapenem-resistant K. pneumoniae and deserves further validation.
  • PublicationOpen Access
    Review on the Antibacterial Mechanism of Plant-Derived Compounds against Multidrug-Resistant Bacteria (MDR)
    (2021-08-01T00:00:00Z) Jubair, Najwan; Rajagopal, Mogana; Chinnappan, Sasikala; Abdullah, Norhayati Binti; FATIMA, AYESHA; FATIMA, AYESHA
    Microbial resistance has progressed rapidly and is becoming the leading cause of death globally. The spread of antibiotic-resistant microorganisms has been a significant threat to the successful therapy against microbial infections. Scientists have become more concerned about the possibility of a return to the pre-antibiotic era. Thus, searching for alternatives to fight microorganisms has become a necessity. Some bacteria are naturally resistant to antibiotics, while others acquire resistance mainly by the misuse of antibiotics and the emergence of new resistant variants through mutation. Since ancient times, plants represent the leading source of drugs and alternative medicine for fighting against diseases. Plants are rich sources of valuable secondary metabolites, such as alkaloids, quinones, tannins, terpenoids, flavonoids, and polyphenols. Many studies focus on plant secondary metabolites as a potential source for antibiotic discovery. They have the required structural properties and can act by different mechanisms. This review analyses the antibiotic resistance strategies produced by multidrug-resistant bacteria and explores the phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics.