Publications by authors named "Hafsa Naseem"

2 Publications

  • Page 1 of 1

Characterization of a lytic EBP bacteriophage with large size genome against Enterobacter cloacae.

APMIS 2021 May 5. Epub 2021 May 5.

Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan, 54590, Pakistan.

Enterobacter cloacae (E. cloacae) is an emerging nosocomial pathogen that had acquired antibiotic resistance against multiple classes of antibiotics. The current study was aimed to isolate and characterize lytic bacteriophage against E. cloacae. The bacteriophage EBP was isolated from a sewage water sample using E. cloacae as a host strain by double-layer agar technique. EBP was found stabile at a wide range of temperatures (25, 37, 60, and 80°C) and pH (5, 6, 7, 8, and 9) with antibacterial activity up to 24 h of infection. The latent period of EBP was 20 min with a burst size of 252 phages per cell. It showed a narrow host range and infected 12/21 (57%) isolates of E. cloacae tested. It has helical symmetry with a head size of 105 and 120 nm long tail with contractile sheath. The EBP has 179.1 kb long double-stranded DNA genome with 44.8% GC content. Majority of identified ORFs (187/281) were encoding putative proteins with unknown function. Necessary replication enzymes, structural proteins, and lytic enzymes were detected in the genome of EBP. Phylogenetic analysis revealed that EBP closely resembles with Coronobacter phage vB_CsaM_IeN, vB_CsaM_IeE, vB_CsaM_IeB, and Citrobacter phage Margaery. Based on electron microscopy and molecular characterization, EBP was classified as a Myoviridae phage.
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http://dx.doi.org/10.1111/apm.13138DOI Listing
May 2021

Exopolysaccharides producing rhizobacteria and their role in plant growth and drought tolerance.

J Basic Microbiol 2018 Dec 5;58(12):1009-1022. Epub 2018 Sep 5.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Drought stress not only effect the population and activities of microorganisms inhabiting the rhizosphere but also various physiological and biochemical process in plants that is, photosynthesis, respiration, translocation, uptake of ions, carbohydrates, and nutrient metabolism. Plant growth promoting rhizobacteria (PGPR) and their exopolysaccharides (EPS) showed profound effects on plant growth and drought tolerance. Reactions of bacteria to drought stress at various organizational levels are different which depends on intensity of stress, duration, species, and growth stage. PGPR could be effectively utilized in developing strategies to facilitate water conservation strategies of plants. They have the ability to improve plant growth directly by enhancing level of phytohormones, siderophore, biofilm, and exopolysaccharides production and by increasing the nutrient availability in the rhizosphere or indirectly by protecting plants from pathogen attack. EPS producing bacteria are capable to maintain higher soil moisture content and growth of plants even under severe dried sandy soils. The evidence of survival of rhizobacteria under low moisture content obtained from the fact of rhizobacterial occurrence in the soil of desert and effective nodule formation in desert soil. Beside this, EPS produced by PGPR form rhizosheath around the roots and thus protect the plant roots from desiccation for a longer period of time. Important role exhibited by exopolysaccharides includes, protection from desiccation, microbial aggregation, plant-microbe interaction, surface attachment, bioremediation and its use by many industries for stabilizing, thickening, coagulating, gelling, suspending and for film forming. Plants inoculated with EPS-producing bacteria showed higher accumulation of proline, sugars, and free amino acids under water deficit stress. Biofilms formed by the PGPR around the roots are made up of bacterial populations or bacterial communities that encased inside the polymeric extracellular matrix formed by bacteria itself, they adhered to the external surfaces that contain sufficient moisture. It is concluded that the application of PGPR in combination with their EPS is a promising measure to combat drought stress thus, increasing global food security.
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http://dx.doi.org/10.1002/jobm.201800309DOI Listing
December 2018