Introduction Nanotechnology is relatively a new science of study in which a set of sciences, including the STEM (science, technology, engineering, and mathematics) disciplines, are involved to synthesize nanomaterials of about 1-100 nm. At the nanoscale level, materials have distinct chemical, physical, optical, magnetic, and electrical properties due to their large surface area to volume ratio (Chaturvedi et al., 2012). One of the most important aspects of nanotechnology is the synthesis of nanoparticles (NPs), which form the essence of nanomaterials (Ishida et al., 2014). NPs exhibit new properties based on specific characteristics such as size, distribution, and morphology. Today NPs are used in many fields, including manufacturing and materials, environmental sciences, energy and electronics, and medicine. Multidrug-resistant (MDR) microbes are a growing problem in the treatment of infectious diseases due to the widespread use of broad-spectrum antibiotics, which has resulted in the production of antibiotic resistance for many human bacterial pathogens (Franci et al., 2015). Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of NPs, which are now considered a viable alternative to antibiotics and seem to have high potential in solving the problem of the emergence of microbial multidrug resistance (Rai et al., 2012). During the last decade, increased interest has been paid to biological systems for the synthesis of NPs compared with other methods, i.e. physical and chemical methods. The latter approaches are expensive and have many limitations; therefore, scientists are developing clean, economical, and ecofriendly biological approaches as an alternative for NP synthesis (Rai et al., 2009; Seshadri et al., 2011; Wei et al., 2012). Microorganisms (mainly bacteria, yeasts, and molds) have efficiently proven their ability to absorb and accumulate inorganic metallic ions from the surrounding environment. More importantly, the ability of a biological entity to use its inherent biochemical processes to transform inorganic metallic ions into metal NPs has led to a relatively new and largely unexplored field of research. Among microbes, filamentous fungi are widely used as biocatalysts in NP preparation (

Finding a safe and broad-spectrum medication is a goal of scientists, pharmacists, and physicians, but developing and fabricating the right medicine can be challenging. The current study describes the formation of silver nanoparticles (AgNPs) by Fusarium mangiferae. It involves the antibiofilm activity of the nanoparticles against Staphylococcus aureus. It also involves cytotoxic effect against mammalian cell lines. Well-dispersed nanoparticles are formed by F. mangiferae. The sizes of the nanoparticles were found to range from 25 to 52 nm, and UV-Vis scan showed absorption around 416-420 nm. SEM, TEM, and AFM results displayed spherical and oval shapes. Furthermore, the FTIR histogram detected amide I and amide II compounds responsible for the stability of AgNPs in an aqueous solution. AgNPs were observed to decrease the formation of biofilm at 75% (v/v). DNA reducing, smearing, and perhaps fragmentation were noticed after treating the bacterial cells with 50% (v/v). Additionally, cell lysis was detected releasing proteins in the supernatant. It was also observed that the AgNPs have the ability to cause 59% cervical cancer cell line (HeLa) deaths at 25% (v/v), however, they showed about 31% toxicity against rat embryo fibroblast transformed cell lines (REF). The results of this study prove the efficiency of AgNPs as an antibiofilm against S. aureus, suggesting that AgNPs could be an alternative to antibiotics. It must also be emphasized that AgNPs displayed cytotoxic behavior against mammalian cell lines. Further studies are needed for assessing risk in relation to the possible benefit of prescribing AgNPs.

No abstract

The uncontrolled discharge of industrial wastes causes the accumulation of high heavy metal concentrations in soil and water, leading to many health issues. In the present study, a Gram-negative Aeromonas sobria was isolated from heavily contaminated soil in the Tanjaro area, southwest of Sulaymaniyah city in the Kurdistan Region of Iraq; then, we assessed its ability to uptake heavy metals. A. sobria was molecularly identified based on the partial amplification of 16S rRNA using novel primers. The sequence was aligned with 33 strains to analyze phylogenetic relationships by maximum likelihood. Based on maximum tolerance concentration (MTC), A. sobria could withstand Zn, Cu, and Ni at concentrations of 5, 6, and 8 mM, respectively. ICP-OES data confirmed that A. sobria reduced 54.89% (0.549 mM) of the Cu, 62.33% (0.623 mM) of the Ni, and 36.41% (0.364 mM) of the Zn after 72 h in the culture medium. Transmission electron microscopy (TEM) showed that A. sobria accumulated both Cu and Ni, whereas biosorption was suggested for the Zn. These findings suggest that metal-resistant A. sobria could be a promising candidate for heavy metal bioremediation in polluted areas. However, more broadly, research is required to assess the feasibility of exploiting A. sobria in situ.

The rate at which nosocomial infections have spread throughout the globe has been alarming. Therefore, the data presented here sheds light on some aspects of AgNPs as promising anti-infective therapy. However, knowledge on the safe usage of AgNPs in the field of medicine is necessary to investigate. AgNPs synthesis, optimization, characterization, and mode of action against Enterococcus faecalis have been studied in this paper. We propose a combination of cell-free supernatant (C-FS) of the intimate organisms; Fusarium solani and Comamonas aquatica as synthesis catalysts. The optimization findings were at pH 9.0 for 72 h in 1 mM AgNO3 using 1:2 v/v (C-FS : AgNO3). UV-vis absorption peak appeared at 425 nm and the crystalline nature of synthesized particles was verified by XRD. FTIR analysis confirmed the presence of protein molecules that acted as reducing and stabilizing agents. Energy-dispersive X-ray analysis exhibited an intense peak at 3 KeV, confirming the formation of AgNPs. Further, FE-SEM images prove AgNPs synthesis. TEM and AFM analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5 nm. The growth and biofilm of nosocomial E. faecalis were significantly decreased by the action of AgNPs. Furthermore, antibiotic resistance genes, blaTEM, and blaCTX, were detected in E. faecalis; both genes were degraded enormously via 9 % AgNPs. This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against nosocomial pathogens.