Genetic variations of lacZ gene in Gram-negative bacteria isolated from different water sources. | ||||
| Microbes and Infectious Diseases | ||||
| Articles in Press, Accepted Manuscript, Available Online from 26 August 2025 | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/mid.2025.395774.2916 | ||||
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| Authors | ||||
Abbas Hassan Taqi  1; Muhsin A. Essa 2; Angham J. Alwan 2
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| 1Department of Biology, College of Science, University of Mosul, Iraq | ||||
| 2Biology Department, Science College, Mosul University, Iraq | ||||
| Abstract | ||||
| Background: Environmental pressures in diverse aquatic ecosystems are hypothesized to drive genetic variation in bacterial populations. This study investigates the lacZ gene, a key gene for lactose metabolism, as a marker of such adaptation in Gram-negative bacteria. Methods: We tested the hypothesis that bacteria isolated from different water sources (drinking water, river water, and wastewater) would exhibit distinct lacZ gene sequence variations, reflecting adaptation to differing lactose availability and other selective pressures. Nine bacterial isolates belonging to Escherichia coli, Aeromonas hydrophila, and Klebsiella pneumoniae were tested previously isolated and identified from all water sources. lacZ gene was amplified and sequenced of each isolate. Sequences were de-coded to detect single nucleotide polymorphisms (SNP) and indels. Phylogenetic analysis was carried out to evaluate the associations between lacZ sequences at various isolate and reference strains. The inferred amino acid sequences were analyzed in order to define how the identified mutation affects protein structure and protein functionality. Results: There were nine new strains in NCBI and all isolates had lacZ gene. During sequence analysis, missense and silent mutations were detected and characterized dominate by transversions and transitions. Mutations were observed to be different across species and water source. Phylogenetic analysis identified genetic differences and similitude of the local and international strains. Conclusions: It is indicated by these results that environmental factors in various water sources are agents of the genetic diversity of the lacZ gene in these bacteria, which could play a role in their metabolic functions and adaptation to their corresponding niches. | ||||
| Keywords | ||||
| lacZ gene; Gram-negative bacteria; water source; phylogenetic analysis; mutations | ||||
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