Polymeric materials have been essential biomaterials to develop hydrogels as wound dressings for sustained drug delivery and chronic wound healing. The microenvironment for wound healing is created by biocompatibility, bioactivity, and physicochemical behavior. Moreover, a bacterial infection often causes the healing process. The bacterial cellulose (BC) was functionalized using graphene oxide (GO) by hydrothermal method to have bacterial cellulose-functionalized-Graphene oxide (BC-f-GO). A simple blending method was used to crosslink BC-f-GO with polyvinyl alcohol (PVA) by tetraethyl orthosilicate (TEOS) as a crosslinker. The structural, morphological, wetting, and mechanical tests were conducted using Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), water contact angle, and a Universal testing machine (UTM). The release of Silver-sulphadiazine and drug release kinetics were studied at various pH levels and using different mathematical models (zero-order, first-order, Higuchi, Hixson, Korsmeyer–Peppas, and Baker–Lonsdale). The antibacterial properties were conducted against Gram-positive and Gram-negative severe infection-causing pathogens. These composite hydrogels presented potential anticancer activities against the U87 cell line by an increased GO amount. The result findings show that these composite hydrogels have physical-mechanical and inherent antimicrobial properties and controlled drug release, making them an ideal approach for skin wound healing. As a result, these hydrogels were discovered to be an ideal biomaterial for skin wound healing.

IscU, the central scaffold protein in the bacterial ISC iron-sulfur (Fe-S) cluster biosynthesis system, has long been recognized to bind a Zn ion at its active site. While initially regarded as an artifact, Zn binding has been shown to induce stabilization of the IscU structure that may mimic a state biologically relevant to IscU's role in Fe-S cluster biosynthesis. More recent studies have revealed that SufU, a homologous protein involved in Fe-S cluster biosynthesis in Gram-positive bacteria, also binds a Zn ion with structural implications. Given the widespread occurrence of the "IscU-like" protein fold, particularly among Fe-S cluster biosynthesis systems, an interesting question arises as to whether Zn ion binding and the resulting structural alterations are common properties in IscU-like proteins. Interactions between IscU and specific metal ions are investigated and compared side-by-side with those of SufU from a representative Gram-positive bacterium in the phylum Firmicutes. These studies were extended with additional transition metal ions chosen to investigate the influence of coordination geometry on selectivity for binding at the active sites of IscU and SufU. Monitoring and comparing the conformational behavior and stabilization afforded by different transition metal ions upon IscU and SufU revealed similarities between the two proteins and suggest that metal-dependent conformational transitions may be characteristic of U-type proteins involved in Fe-S cluster biosynthesis.

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The rapidly growing global problem of infectious pathogens acquiring resistance to conventional antibiotics is an instigating reason for researchers to continue the search for functional as well as broad-spectrum antimicrobials. Hence, we aimed in this study to synthesis silver–copper oxide (Ag-CuO) nanohybrids as a function of Ag concentration (0.05, 0.1, 0.3 and 0.5 g) via the one-step hydrothermal method. The bimetallic Ag-CuO nanohybrids Ag-C-1, Ag-C-2, Ag-C-3 and Ag-C-4 were characterized for their physico-chemical properties. The SEM results showed pleomorphic Ag-CuO crystals; however, the majority of the particles were found in spherical shape. TEM results showed that the Ag-CuO nanohybrids in formulations Ag-C-1 and Ag-C-3 were in the size range of 20–35 nm. Strong signals of Ag, Cu and O in the EDX spectra revealed that the as-synthesized nanostructures are bimetallic Ag-CuO nanohybrids. The obtained Ag-C-1, Ag-C-2, Ag-C-3 and Ag-C-4 nanohybrids have shown their MICs and MBCs against E. coli and C. albicans in the range of 4–12 mg/mL and 2–24 mg/mL, respectively. Furthermore, dose-dependent toxicity and apoptosis process stimulation in the cultured human colon cancer HCT-116 cells have proven the Ag-CuO nanohybrids as promising antiproliferative agents against mammalian cancer.

Iron‐sulfur (Fe‐S) clusters are critical cofactors necessary for the function of myriad proteins, including those involved in respiration, photosynthesis, DNA repair, and more. Fe‐S cluster biosynthesis is nearly universally required in all organisms. Three assembly machineries, ISC, NIF and SUF have been identified, and all are represented among bacteria. Escherichia coli, a Gram− bacterium, has both ISC and SUF systems; most Gram+ bacteria, including Bacillus subtilis and Streptococcus mutans, have only one system (SUF). These Fe‐S assembly systems include a cysteine desulfurase enzyme, either IscS or SufS, which provides the sulfide constituent for Fe‐S cluster assembly. A scaffold protein is another critical component, serving as a platform for cluster assembly and participating in transfer of the clusters to target apoproteins. In E. coli, IscU is recognized as a scaffold protein in the ISC system, whereas SufBCD complex is the scaffold protein in the SUF system. In B. subtilis and S. mutans, SufU has been suggested to be a scaffold protein; however, SufU has also been found to enhance the activity of its cognate SufS desulfurase. Similarities in secondary structure, amino acid sequences, and metal binding to the active sites of IscU and SufU predict that these two U‐type proteins share other properties and functions; specifically, structural dynamics in response to binding metal ions, and also metal ion specificity. This study aims to (1) characterize the behavior of B. subtilis SufU toward two different transition metal ions (Zn2+ and Fe3+), and (2) compare and contrast conformational changes the B. subtilis protein undergoes upon binding these metal ions to those of E. coli IscU and S. mutans SufU. Experimental approaches include colorimetry, Isothermal Titration Calorimetry (ITC), Dynamic Light Scattering (DLS), Circular Dichroism (CD), and tryptophan fluorescence. Colorimetry using 4‐(2‐pyridylazo) resorcinol revealed that SufU was purified with bound Zn2+. Based on ITC, Zn2+ binds to SufU at a single site with Kd value of 7.11 μM. This was corroborated using an assay based on intrinsic tryptophan fluorescence. There was no evidence of Fe3+ binding using either approach. The results indicated that purified SufU that had been stripped of its bound Zn2+ undergoes conformational changes upon reconstitution with Zn2+ ions. By contrast, no indication of such changes was obtained upon the addition of Fe3+ ions. Thus, B. subtilis SufU discriminates between Zn2+ and Fe3+ ions, with preference for the former. These properties are shared with E. coli IscU and S. mutans SufU, suggesting that they are widespread characteristics of U‐type proteins that participate in Fe‐S cluster biosynthesis. The findings for B. subtilis SufU contribute to a broader understanding of the kinds of protein‐protein interactions and structural adaptability that are associated with binding of metal ions to scaffold proteins. They should also be useful in investigating features that are distinctive to subsets of these proteins, such as the Gram Positive Region (GPR), which is absent from the E. coli IscU.Support or Funding InformationBowling Green State UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.