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INNOSC Theranostics and
Pharmacological Sciences Activity of green-synthesized nanoparticles

involved in electron transfer and energy production, KQ76_RS08360, fmtA, KQ76_RS01520, KQ76_RS13020,
40
whereas the ferric enterobactin receptor is an outer hssR, ylqF, dltB, KQ76_RS11280/KQ76_RS11285, KQ76_
membrane protein responsible for transporting iron into RS01815, smpB, KQ76_RS07375, purS, mnmG, KQ76_
the periplasm. 42-45 Mutations affecting iron transport RS12955, and KQ76_RS10985.
systems can lead to antimicrobial resistance by impairing Describing the function of these genes is crucial
iron uptake. This is significant because many antibiotics for understanding how K. pneumoniae adapts to its
rely on iron transport pathways to enter bacterial cells. environment, particularly in relation to antibiotic resistance,
46
Consequently, limiting iron acquisition can enhance pathogenicity, and microbial evolution. Mutations in these
bacterial resistance to antimicrobial agents. genes can significantly alter bacterial traits by affecting key
The nutrient broth medium provides a rich source of cellular processes such as metabolism, virulence factor
readily available nutrients – such as carbohydrates, protein, expression, and drug susceptibility.
vitamins, and minerals – that enable K. pneumoniae to The following are the functions of the mutated genes
efficiently access nutrients necessary for rapid growth and identified in K. pneumoniae control cells:
proliferation. In the control group, mutations are detected (i) sfaA/sfaD is involved in the transport of iron from
25
in K. pneumoniae cells grown in this nutrient-rich medium. the environment into the cell, supporting essential
These mutations appear to confer advantageous traits that cellular processes. 47
enhance nutrient utilization, allowing the control cells to (ii) KQ76_RS08360 enables the recycling of adenine, a
outcompete the treated cells and display increased growth. critical building block of DNA. 48
Several notable mutations are observed in the control (iii) fmtA is involved in cell division and bacterial cell wall
cells, particularly in genes related to iron metabolism, synthesis. 49
biosynthesis, metabolism, cell growth, detoxification, (iv) KQ76_RS13020 belongs to a large enzyme superfamily
cell wall integrity, structural stability, defense, and stress with diverse catalytic functions, including roles in
50
responses. These mutations likely provide a competitive cell growth, metabolism, and detoxification.
advantage in the nutrient-rich media. This also raises (v) hssR regulates gene expression related to iron
concerns about stress-induced mutagenesis, as the observed metabolism and other cellular activities. 51
mutations in the control group may reflect an elevated (vi) ylqF assists in the assembly and regulation of
rate of adaptive mutation – potentially contributing ribosomes. GTPases also regulate cellular functions. 52
to future resistance development in K. pneumoniae. (vii) dltB maintains cell wall integrity and regulates cation
Nevertheless, the study demonstrates that biosynthesized balance, contributing to resistance against cationic
silver nanoparticles effectively inhibit bacterial growth, antimicrobial peptides. 53
suggesting a cytotoxic effect of silver nanoparticles that (viii) KQ76_RS11280/KQ76_RS11285 facilitates bacterial
interferes with essential cellular processes and disrupts competition for resources or consumption of other
normal cell function. bacteria. 54
(ix) KQ76_RS01815 promotes bacterial survival under
Mutations can arise spontaneously without exposure
to external stressors and are a key driver of bacterial environmental stresses and induces virulence factor
expression.
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evolution. In untreated bacterial cells, mutations may result (x) smpB is involved in tagging and degrading proteins
from natural genetic alterations during DNA replication. produced from defective mRNAs and plays a role in
While many of these changes are neutral, some may nutrient acquisition. 56
confer advantageous traits – such as increased antibiotic (xi) KQ76_RS07375 triggers bacterial defense
resistance – that enhance bacterial survival in challenging mechanisms. 57
environments, including exposure to antimicrobials. 12
(xii) purS is involved in the purine biosynthetic pathway. 58
These findings highlight a critical concern: the (xiii) mnmG is crucial for accurate codon-anticodon
presence of resistance genes may render nanoparticles pairing during protein translation. 59
ineffective. Such genes can reduce nanoparticle efficacy (xiv) KQ76_RS12955 is a key enzyme in glycolysis. 60
through several mechanisms, including actively expelling Mutations identified in E. coli-treated cells involve genes
nanoparticles, modifying the cell membrane to prevent associated with transport, cell division, biosynthetic
nanoparticle entry, and chemically altering nanoparticles adaptation, and invasion:
to reduce their toxicity.
(i) L-lysine exporter LysO/aquaporin Z (lysO/aqpZ)
Genomic analysis reveals several mutations in the mediates the export of L-lysine and confers resistance
genes of control K. pneumoniae cells, including sfaA/sfaD, to the toxic antimetabolite L-thialysine. 61

Volume 8 Issue 3 (2025) 79 doi: 10.36922/ITPS025080007