Illuminating new possibilities: Effects of copper oxide nanoparticles on gastrointestinal adenocarcinoma cells in hypoxic condition.

Cancer remains a major global health concern, necessitating the development of novel therapeutic approaches. Hypoxia is a common characteristic of solid tumors that plays a critical role in tumor progression, making it a prime target for anticancer therapies. This study aimed to determine the effects of copper oxide nanoparticles (CuONPs) on human gastrointestinal cancer cells in hypoxic condition for the first time. Toxicity of CuONPs was evaluated on human colon and gastric adenocarcinoma cells and normal fibroblasts by alamarBlue assay. Real-time polymerase chain reaction (PCR) was performed to study the effects of CuONPs on genes involved in cell apoptosis. To elucidate the molecular mechanisms underlying the effects of CuONPs in hypoxic condition, molecular docking was conducted on HIF-1α. Results revealed dose- and cell-type-dependent toxic effects of CuONPs, as a more significant (p < 0.0001) decrease in viability of LoVo cells (23 %) was observed compared to MKN-45 and HDF cells. In addition, CuONPs significantly (p < 0.0001) reduced LoVo cell viability down to 30.2 % in hypoxic condition. Gene expression analysis revealed significant (p < 0.0001) overexpression of P53 and BAX but downregulation of BCL-2 and CCND1 after treatment with CuONPs. Molecular docking indicated the preferable binding of CuONPs to the HIF-1α PAS-B domain through interaction with 15 residues with -4.8 kcal/mol binding energy. Our findings open up new possibilities for modulating HIF-1 activity and inhibiting hypoxia-induced tumor progression.

Bacterial-mediated synthesis and characterization of copper oxide nanoparticles with antibacterial, antioxidant, and anticancer potentials.

The application of novel bacterial strains for effective biosynthesis of nanoparticles minimizes negative environmental impact and eliminates challenges of available approaches. In the present study, cell-free extract of Stenotrophomonas sp. BS95. was used for synthesis of copper oxide nanoparticles (CuONPs). Characterization of crude and calcined CuONPs was carried out by UV-vis spectroscopy, X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, zeta potential, dynamic light scattering, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Afterward, biogenic CuONPs were evaluated for antibacterial, antioxidant, and cytotoxic effects using broth micro-dilution method, DPPH assay and alamarBlue assay, respectively. Finally, molecular mechanisms behind anticancer effects of CuONPs was ascertained by real time PCR. UV-vis absorbance spectra registered surface plasmon resonance peaks at 286 nm and 420 nm for crude and calcined CuONPs, respectively. FTIR spectra exhibited bands associated with organic functional groups of bacterial proteins, confirming capping and functionalization of CuONPs. The average crystallite size of crude and calcined CuONPs was determined as 18.24 and 21.3 nm by XRD, respectively. The average zeta potentials of crude and calcined CuONPs were as -28.57 ± 5.13 and -29.47 ± 4.78 mV, respectively, indicating their high stability. Electron microscopy revealed that crude and calcined CuONPs were roughly spherical particles with an average size of 35.24 ± 4.64 and 43.68 ± 2.31 nm, respectively. Biogenic CuONPs induced antibacterial effects with minimal inhibitory concentrations ranging from 62.5 to 1,000 µg/ml against Gram-negative and Gram-positive strains. The antioxidant activity of crude and calcined CuONPs was found to be 83% ± 2.64% and 78% ± 1.73%, respectively. More intriguingly, CuONPs exerted considerable cytotoxic effects on human colon and gastric adenocarcinoma cells, while induced low toxicity on normal cells. Anticancer effects of biogenic CuONPs were confirmed by significant changes induced in the expression of apoptosis-related genes, including P53, BAX, BCL2 and CCND1. Hence, biosynthesized CuONPs could be considered as potential antimicrobial, antioxidant and anticancer agents.

Application of a marine luminescent Vibrio sp. B4L for biosynthesis of silver nanoparticles with unique characteristics, biochemical properties, antibacterial and antibiofilm activities.

Biosynthesis of silver nanoparticles (AgNPs) by marine bacteria especially luminescent Vibrio species is least investigated. In this study, AgNPs were first synthesized by the culture supernatant of a luminescent bacterium (Vibrio sp. B4L) and then, the prepared samples were characterized employing several techniques. The antibacterial activity of the AgNPs was investigated against Escherichia coli and Staphylococcus aureus using disk diffusion agar and broth microdilution methods. The growth curve, Reactive Oxygen Species (ROS) formation, and Lactate Dehydrogenase (LDH) activity of the samples were measured along with Field Emission Scanning Electron Microscopy (FESEM) observation and inhibition of biofilm formation. Dynamic light scattering (DLS) analysis showed that the average particle size of the synthesized AgNPs was in the range of about 32.67-107.18 nm and the polydispersity index (PDI) of 0.1120 indicated the formation of monodispersed particles. The average zeta potential of AgNPs obtained -36.15 mV, showing the high stability of biosynthetic nanoparticles. Antibacterial studies indicated that not only the AgNPs had antibacterial activity but also increased the antibacterial properties of tetracycline when used in combination. ROS production was enhanced in a dose-dependent manner. A high difference in LDH activities was found between AgNPs treated cells and the control group. FESEM images revealed membrane disruption and lysis in AgNPs treated cells. The formation of E. coli biofilm was 100% inhibited at 62.5 µg/ml showing that our bacteriogenic AgNPs can be a potential alternative remedies for controlling antibiotic-resistant pathogens.

Comparative evaluation of silver nanoparticles biosynthesis by two cold-tolerant Streptomyces strains and their biological activities.

The present study reflected on high-priority biological activities of novel silver nanoparticles (AgNPs) synthesized via two cold-tolerant strains; namely, Streptomyces sp.OSIP1 and Streptomyces sp.OSNP14. These AgNPs were synthesized through a green method using culture supernatant of bacteria at 20 °C and characterized by several instrumental techniques. The TEM results revealed that the NPs obtained from OSIP1 were smaller (8 nm, average) than those taken from OSIP14 (15 nm, average). Both AgNPs-OSP1 and AgNPs-OSNP14 also posed the strongest growth inhibitory effect against several pathogenic bacteria alone and especially in combination with antibiotics. Smaller NPs especially at 3.9-31.25 µg/ml concentrations were assumed more effective biofilm inhibitors of Pseudomonas aeruginosa. Cytotoxic activity of both AgNPs (at 25 and 50 µg/mL concentrations) on mouse colorectal carcinoma cells (CT26) were then studied using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The findings demonstrated that smaller AgNPs at a 50 µg/mL concentration had 7% more cytotoxicity effects. In conclusion; although AgNPs produced by diverse strains of cold-adapted Streptomyces had close characteristics and biological activities, they showed some multifarious properties.

Optimization of complete RB-5 azo dye decolorization using novel cold-adapted and mesophilic bacterial consortia.

Azo dyes are an important group of recalcitrant xenobiotics, which are difficult to degrade and deteriorate in cold environments. In this study, two microbial consortia consisting of cold-adapted and mesophilic bacteria were developed for effective decolorization of Reactive Black-5 azo dye. These bacteria were isolated from textile wastewater and soil of a cold region. Identification of bacterial isolates using 16s rRNA gene analysis revealed that they belong to genus Pseudoarthrobacter, Gordonia, Stenotrophomonas, and Sphingomonas. Decolorization assay was performed for every strain at dye concentrations of 25, 50 and 100 mg/L and the consortia PsGo consisting of mesophilic bacteria and StSp consisting of cold-adapted bacteria were constructed accordingly. Results showed that the consortia PsGo and StSp were able to decolorize 54 and 34 percent of RB-5 (50 mg/L) during 7 days. To improve the dye removal efficiency of the consortia, several parameters including temperature, pH, carbon and nitrogen sources were optimized. Over longer periods, StSp consortium managed to completely decolorize RB-5 (50 mg/L) at optimized conditions of 25-30 °C, pH 9, and using glucose and NH4H2PO4 as carbon and nitrogen source respectively, whereas PsGo consortium decolorized RB-5 (50 mg/mL) completely at 37 °C, pH 11, and with lactose and NH4H2PO4 used as carbon and nitrogen sources. Kinetic of reactions for StSp and PsGo consortia were found to be 0.05 and 0.13 day-1 respectively, but became 0.71 and 0.9 day-1 after optimization. In general, cold ecosystems are good sources for the isolation of novel bacterial strains with a potential application, especially when used as consortia, in environmental biotechnology such as decolorization of RB-5.

Biodegradation of phenol by cold-tolerant bacteria isolated from alpine soils of Binaloud Mountains in Iran.

Degradation of phenol is considered to be a challenge because of harsh environments in cold regions and ground waters. Molecular characterization of phenol degrading bacteria was investigated to gain an insight into the biodegradation in cold areas. The psychrotolerant and psychrophiles bacteria were isolated from alpine soils in the northeast of Iran. These strains belonged to Pseudomonas sp., Stenotrophomonas spp. and Shinella spp. based on analysis of the 16S rRNA gene. These strains were capable of the complete phenol degradation at a concentration of 200 mg L-1 at 20 °C. Moreover, the strains could degrade phenol at a concentration of 400 and 600 mg L-1 at a higher time. Effects of environmental factors were studied using one factor at a time (OFAT) approach for Pseudomonas sp.ATR208. When the bacterium was grown in a liquid medium with 600 mg L-1 of concentration supplemented with optimum carbon and nitrogen sources, more than 99% of phenol removal was obtained at 20 °C and 24 h. Therefore, the present study indicated the potential of the local cold tolerant bacteria in the phenol bioremediation.

Microbial diversity in alpine tundra soils correlates with snow cover dynamics.

The temporal and spatial snow cover dynamics is the primary factor controlling the plant communities' composition and biogeochemical cycles in arctic and alpine tundra. However, the relationships between the distribution of snow and the diversity of soil microbial communities remain largely unexplored. Over a period of 2 years, we monitored soil microbial communities at three sites, including contiguous alpine meadows of late and early snowmelt locations (LSM and ESM, respectively). Bacterial and fungal communities were characterized by using molecular fingerprinting and cloning/sequencing of microbial ribosomal DNA extracted from the soil. Herein, we show that the spatial and temporal distribution of snow strongly correlates with microbial community composition. High seasonal contrast in ESM is associated with marked seasonal shifts for bacterial communities; whereas less contrasted seasons because of long-lasting snowpack in LSM is associated with increased fungal diversity. Finally, our results indicate that, similar to plant communities, microbial communities exhibit important shifts in composition at two extremes of the snow cover gradient. However, winter conditions lead to the convergence of microbial communities independently of snow cover presence. This study provides new insights into the distribution of microbial communities in alpine tundra in relation to snow cover dynamics, and may be helpful in predicting the future of microbial communities and biogeochemical cycles in arctic and alpine tundra in the context of a warmer climate.