Flubendiamide provokes oxidative stress, inflammation, miRNAs alteration, and cell cycle deregulation in human prostate epithelial cells: The attenuation impact of synthesized nano-selenium using Trichodermaaureoviride

Flubendiamide (FBD) is a novel diamide insecticide extensively used with potential human health hazards. This research aimed to examine the effects of FBD on PrEC prostate epithelial cells, including Oxidative stress, pro-inflammatory responses, modifications in the expression of oncogenic and suppressor miRNAs and their target proteins, disruption of the cell cycle, and apoptosis. Additionally, the research investigated the potential alleviative effect of T-SeNPs, which are selenium nanoparticles biosynthesized by Trichoderma aureoviride, against the toxicity induced by FBD. Selenium nanoparticles were herein synthesized by Trichoderma aureoviride. The major capping metabolites in synthesized T-SeNPs were Isochiapin B and Quercetin 7,3',4'-trimethyl ether. T-SeNPs showed a spherical shape and an average size between 57 and 96.6 nm. FBD exposure (12 μM) for 14 days induced oxidative stress and inflammatory responses via overexpression of NF-κB family members. It also distinctly caused upregulation of miR-221, miR-222, and E2F2, escorted by downregulation of miR-17, miR-20a, and P27kip1. FBD encouraged PrEC cells to halt at the G1/S checkpoint. Apoptotic cells were drastically increased in FBD-treated sets. Treatment of T-SeNPs simultaneously with FBD revealed its antioxidant, anti-inflammatory, and antitumor activities in counteracting FBD-induced toxicity. Our findings shed light on the potential FBD toxicity that may account for the neoplastic transformation of epithelial cells in the prostate and the mitigating activity of eco-friendly synthesized T-SeNPs.

Biochemical characterization, biosynthesis mechanism, and functional evaluation of selenium-enriched Aspergillus oryzae A02

The synthesis mechanisms and function evaluation of selenium(Se)-enriched microorganism remain relatively unexplored. This study unveils that total Se content within A. oryzae A02 mycelium soared to an impressive 8462 mg/kg DCW, surpassing Se-enriched yeast by 2-3 times. Selenium exists in two predominant forms within A. oryzae A02: selenoproteins (SeMet 32.1 %, SeCys 14.4 %) and selenium nanoparticles (SeNPs; 53.5 %). The extensive quantitative characterization of the elemental composition, surface morphology, and size of SeNPs on A. oryzae A02 mycelium significantly differs from those reported for other microorganisms. Comparative RNA-Seq analysis revealed the upregulation of functional genes implicated in selenium transformation, activating multiple potential pathways for selenium reduction. The assimilatory and dissimilatory reductions of Se oxyanions engaged numerous parallel and interconnected pathways, manifesting a harmonious equilibrium in overall Se biotransformation in A. oryzae A02. Furthermore, selenium-enriched A. oryzae A02 was observed to primarily upregulate peroxisome activity while downregulating estrogen 2-hydroxylase activity in mice hepatocytes, suggesting its potential in fortifying antioxidant physiological functions and upholding metabolic balance.

Enhanced Induction of Apoptosis and Cell Cycle Arrest in MCF-7 Breast Cancer and HT-29 Colon Cancer Cell Lines via Low-Dose Biosynthesis of Selenium Nanoparticles Utilizing Lactobacillus casei

As a leading global cause of mortality, cancer continues to pose a significant challenge. The shortcomings of prevalent cancer treatments, such as surgery, radiation therapy, and chemotherapy, necessitate the exploration of alternative therapeutic strategies. Selenium nanoparticles (SeNPs) have emerged as a promising solution, with their synthesis being widely researched due to their potential applications. Among the diverse synthesis methods for SeNPs, the green chemistry approach holds a distinctive position within nanotechnology. This research delves into the anti-proliferative and anticancer properties of green-synthesized SeNPs via the cell-free supernatant (CFS) of Lactobacillus casei (LC-SeNPs), with a specific focus on MCF-7 and HT-29 cancer cell lines. SeNPs were synthesized employing the supernatant of L. casei. The characterization of these green-synthesized SeNPs was performed using TEM, FE-SEM, XRD, FT-IR, UV-vis, energy-dispersive X-ray spectroscopy, and DLS. The biological impact of LC-SNPs on MCF-7 and HT-29 cancer cells was examined via MTT, flow cytometry, scratch tests, and qRT-PCR. Both FE-SEM and TEM images substantiated the spherical shape of the synthesized nanoparticles. The biosynthesized LC-SNPs reduced the survival of MCF-7 (by 20%) and HT-29 (by 30%) cells at a concentration of 100 μg/mL. Flow cytometry revealed that LC-SNPs were capable of inducing 28% and 23% apoptosis in MCF-7 and HT-29 cells, respectively. In addition, it was found that LC-SNPs treated MCF-7 and HT-29 cells were arrested in the sub-G1 phase. Gene expression analysis indicated that the expression levels of the CASP3, CASP9, and BAX genes were elevated after treating MCF-7 and HT-29 cells with LC-SNPs. Further, SeNPs were observed to inhibit migration and invasion of MCF-7 and HT-29 cancer cells. The SeNPs, produced via L. casei, demonstrated strong anticancer effects on MCF-7 and HT-29 cells, suggesting their potential as biological agents in cancer treatment following additional in vivo experiments.

Selenium volatilization in plants, microalgae, and microorganisms

The augmented prevalence of Se (Se) pollution can be attributed to various human activities, such as mining, coal combustion, oil extraction and refining, and agricultural irrigation. Although Se is vital for animals, humans, and microorganisms, excessive concentrations of this element can give rise to potential hazards. Consequently, numerous approaches have been devised to mitigate Se pollution, encompassing physicochemical techniques and bioremediation. The recognition of Se volatilization as a potential strategy for mitigating Se pollution in contaminated environments is underscored in this review. This study delves into the volatilization mechanisms in various organisms, including plants, microalgae, and microorganisms. By assessing the efficacy of Se removal and identifying the rate-limiting steps associated with volatilization, this paper provides insightful recommendations for Se mitigation. Constructed wetlands are a cost-effective and environmentally friendly alternative in the treatment of Se volatilization. The fate, behavior, bioavailability, and toxicity of Se within complex environmental systems are comprehensively reviewed. This knowledge forms the basis for developing management plans that aimed at mitigating Se contamination in wetlands and protecting the associated ecosystems.

Comparison of Nutritional Availability of Biogenic Selenium Nanoparticles and Chemically Synthesized Selenium Nanoparticles

Selenium (Se) is an essential micronutrient, and animals biosynthesize selenoproteins from various selenocompounds such as inorganic salts and organic selenocompounds as a Se source. In addition to the inorganic and organic forms of Se, it is also known that elemental Se is biologically synthesized at the nanoscale in nature. Biologically synthesized Se nanoparticles (Se-NPs), i.e., biogenic Se-NPs (Se-BgNPs), have not been fully investigated as a Se source compared with the other forms of Se. In this study, we evaluated the nutritional availability of Se-BgNPs biosynthesized in E. coli and revealed that Se-BgNPs were less assimilated into selenoproteins in rats as a Se source than inorganic Se salt or chemically synthesized Se-NPs. Se-BgNPs showed tolerance toward digestion and low absorbability in gut, which resulted in the low nutritional availability. Se-BgNPs seem to be coated with a biomaterial that functions to reduce their toxicity toward E. coli and at the same time lowers their availability to animals.

Biosynthesis of selenium nanoparticles by lactic acid bacteria and areas of their possible applications

Lactic acid bacteria, being generally recognized as safe, are the preferred choice among other microbial producers of selenium nanoparticles. For successful production of SeNPs, it is necessary to take into account the physiological properties of the bacterium used as a biotransformer of inorganic forms of selenium in Se⁰. The antimicrobial and antioxidant activity of SeNPs allows to use them in the form of pure nanoparticles or biomass of lactic acid bacteria enriched with selenium in preparation of food, in agriculture, aquaculture, medicine, veterinary, and manufacturing of packing materials for food products. To attract attention to the promising new directions of lactic acid bacteria applications and to accelerate their implementation, the examples of the use of SeNPs synthesized by lactic acid bacteria in the mentioned above areas of human activity are described.

Anaerobiosis favors biosynthesis of single and multi-element nanostructures

Herein we report the use of an environmental multimetal(loid)-resistant strain, MF05, to biosynthesize single- or multi-element nanostructures under anaerobic conditions. Inorganic nanostructure synthesis typically requires methodologies and conditions that are harsh and environmentally hazardous. Thus, green/eco-friendly procedures are desirable, where the use of microorganisms and their extracts as bionanofactories is a reliable strategy. First, MF05 was entirely sequenced and identified as an Escherichia coli-related strain with some genetic differences from the traditional BW25113. Secondly, we compared the CdS nanostructure biosynthesis by whole-cell in a design defined minimal culture medium containing sulfite as the only sulfur source to obtain sulfide reduction from a low-cost chalcogen reactant. Under anaerobic conditions, this process was greatly favored, and irregular CdS (ex. 370 nm; em. 520-530 nm) was obtained. When other chalcogenites were tested (selenite and tellurite), only spherical Se0 and elongated Te0 nanostructures were observed by TEM and analyzed by SEM-EDX. In addition, enzymatic-mediated chalcogenite (sulfite, selenite, and tellurite) reduction was assessed by using MF05 crude extracts in anaerobiosis; similar results for nanostructures were obtained; however Se0 and Te0 formation were more regular in shape and cleaner (with less background). Finally, the in vitro nanostructure biosynthesis was assessed with salts of Ag, Au, Cd, and Li alone or in combination with chalcogenites. Several single or binary nanostructures were detected. Our results showed that MF05 is a versatile anaerobic bionanofactory for different types of inorganic NS. synthesis.

The removal of selenite and cadmium by immobilized biospheres: Efficiency, mechanisms and bacterial community

In this study, a complex bacterial consortium was enriched from a typical Pb-Zn mine area and immobilized by sodium alginate to form biospheres, which were used for treatment of selenite (Se(IV))- and cadmium (Cd(II))-containing wastewater without external carbon source. Batch experiments showed that the maximum Se(IV) removal efficiency was 92.36% under the optimal conditions of an initial pH of 5, dosage of 5 g/L, initial Se(IV) concentration of 7.9 mg/L and reaction time of 168 h. Subsequently, more than 99% of 11.2 mg/L Cd(II) was removed by the biospheres within 10 h. Physicochemical characterization showed that reduction and adsorption were the main mechanisms for Se(IV) and Cd(II) removal, respectively. During the removal process, selenium and CdSe nanoparticles were formed. Bacterial community analysis showed the dominant bacterial genera changed after treatment of Se(IV)- and Cd(II)-containing wastewater. Additionally, 16S rRNA gene function prediction results showed that amino acid transport, carbohydrate transport, ion transport and metabolism were the dominant gene functions. The present study provides a potential way for the biological treatment of Se(IV)- and Cd(II)-containing wastewater using immobilized biospheres without external carbon source in short-term.

Harnessing endophytic fungi for biosynthesis of selenium nanoparticles and exploring their bioactivities

In the light of the fast growing several applications of selenium nanoparticles (SeNPs) in different industrial and agricultural sectors, this paper was conducted to explore the suitability of endophytic fungi as nano-factories for SeNPs. Thus, 75 fungal isolates were recovered from plant tissues and tested for their efficacy to biosynthesize SeNPs. Four promising strains were found able to synthesis SeNPs with different characteristics and identified. These strains were Aspergillus quadrilineatus isolated from the twigs of Ricinus communis, Aspergillus ochraceus isolated from the leaves of Ricinus communis, Aspergillus terreus isolated from the twigs of Azadirachta indica, and Fusarium equiseti isolated from the twigs of Hibiscus rose-sinensis. The synthesized SeNPs were characterized by several techniques viz., UV–Vis, X-ray diffraction, Dynamic light scattering analyses, High resolution transmission electron microscopy, and Fourier transform infrared spectroscopy, to study their crystalline structure, particle sized distribution, and morphology. Furthermore, the in vitro antimicrobial and antioxidant activities were evaluated. SeNPs synthesized by the four strains showed potent antifungal and antibacterial potentials against different human and phyto- pathogens. Moreover, SeNPs synthesized by the respective strains showed promising antioxidant power with IC₅₀ values of 198.32, 151.23, 100.31, and 91.52 µg mL^− 1. To the best of our knowledge, this is the first study on the use of endophytic fungi for SeNPs’ biosynthesis. The presented research recommends the use of endophytic fungi as facile one-pot production bio-factories of SeNPs with promising characteristics.

Discovery of four different promising endophytic fungi for a facile-synthesis of SeNPs.

SeNPs were successfully mycosynthesized and characterized.

SeNPs exhibited promising antifungal, antibacterial, and antioxidant activities.

Biogenesis of selenium nanospheres using Halomonas venusta strain GUSDM4 exhibiting potent environmental applications

Selenite reducing bacterial strain (GUSDM4) isolated from Mandovi estuary of Goa, India was identified as Halomonas venusta based on 16S rRNA gene sequence analysis. Its maximum tolerance level for sodium selenite (Na₂SeO₃) was 100 mM. The 2, 3-diaminonaphthalene-based spectroscopic analysis demonstrated 96 and 93% reduction of 2 and 4 mM Na₂SeO₃ respectively to elemental selenium (Se⁰) during the late stationary growth phase. Biosynthesis of Se nanoparticles (SeNPs) commenced within 4 h during the log phase, which was evident from the brick red color in the growth medium and a characteristic peak at 265 nm revealed by UV-Vis spectrophotometry. The intracellular periplasmic synthesis of SeNPs in GUSDM4 was confirmed by transmission electron microscopy (TEM). Characterization of SeNPs by X-ray crystallography, TEM and energy-dispersive X-ray analysis (EDAX) clearly demonstrated spherical SeNPs of 20-80 nm diameter with hexagonal crystal lattice. SeNPs (0.8 and 1 mg/L) primed seeds under arsenate [As(V)] stress showed increase in shoot length, root length and biomass by 1.4-, 1.5- and 1.1-fold respectively, as compared to As(V) primed seeds alone. The proline and phenolic content in seeds primed with SeNPs under arsenate stress showed alleviated levels proving its ameliorative potential. SeNPs also demonstrated anti-biofilm activity at 20 µg/mL against human pathogens which was evident by scanning electron microscopic (SEM) analysis. SeNPs interestingly revealed mosquito larvicidal activity also. Therefore, these studies have clearly demonstrated amazing potential of the marine bacterium, Halomonas venusta in biosynthesis of SeNPs and their applications as ameliorative, anti-biofilm and mosquito larvicidal agents which is the first report of its kind.

Use of Chemical Nano-Selenium as an Antibacterial and Antifungal Agent in Quail Diets and Its Effect on Growth, Carcasses, Antioxidant, Immunity and Caecal Microbes

Nano-minerals are used to enhance mineral bioavailability, which helps improve animal growth and health. The use of chemical nano-selenium (Che-SeNPs) has lately attracted great scientific interest, mainly due to its potential benefits for poultry. The current study was conducted to investigate the impact of the dietary supplementation of Che-SeNPs on the growth performance, carcass traits, blood constituents, antioxidant status, immunity, and gut microbiota of Japanese quails. A total of one week-old 180 Japanese quails were randomly distributed into four equal groups, and each group consisted of 45 unsexed birds with five replications (nine birds each). The first group was fed a basal diet without supplementation (0 g/kg Che-SeNPs), and the second, third, and fourth groups were fed diets containing 0.2, 0.4, and 0.6 g/kg Che-SeNPs, respectively. The results showed that the dietary supplementation of Che-SeNPs significantly (p < 0.0001) increased body weight, body weight gain, and feed conversion ratio, but decreased feed intake (p < 0.0001) compared to the control group. The highest values of growth performance were recorded in the group fed 0.4 g Che-SeNPs g/kg feed. Che-SeNPs levels did not affect the carcass traits, relative organs (except liver), or blood hematology (except platelet count and hemoglobin level) of quails. Plasma total protein, albumin, aspartate amino transferase (AST), and urea values were not affected by dietary Che-SeNPs, but alanine aminotransferase and lactate dehydrogenase values declined. Globulin and creatinine values were linearly increased with the inclusion of Che-SeNPs (0.4 and 0.6 g/kg) in quail diets compared to the control. The supplementation of Che-SeNPs in quail diets significantly improved (p < 0.05) the plasma lipid profile and activities of antioxidant enzymes compared to the control group. Immunoglobulin G values of Che-SeNPs (0.4 and 0.6 g/kg) were higher (p < 0.05) than those in the control group. The groups fed diets supplemented with Che-SeNPs showed lower (p < 0.0001) total bacterial count, total yeast and molds count, Coliform, Escherichia coli, Enterococcus spp., and Salmonella spp. colonization, and higher (p = 0.0003 and 0.0048) lactic acid bacteria counts than those in the control group. In conclusion, Che-SeNPs supplemented up to 0.4 g/kg can improve the performance, lipid profile, antioxidant indices, and immunity, as well as decrease intestinal pathogens in quails during the fattening period (1-5 weeks of age).

Protective prospects of eco-friendly synthesized selenium nanoparticles using Moringa oleifera or Moringa oleifera leaf extract against melamine induced nephrotoxicity in male rats

Nanotechnology is used in a wide range of applications, including medical therapies that precisely target disease prevention and treatment. The current study aimed firstly, to synthesize selenium nanoparticles (SeNPs) in an eco-friendly manner using Moringa oleifera leaf extract (MOLE). Secondly, to compare the protective effects of green-synthesized MOLE-SeNPs conjugate and MOLE ethanolic extract as remedies for melamine (MEL) induced nephrotoxicity in male rats. One hundred and five male Sprague Dawley rats were divided into seven groups (n = 15), including 1st control, 2nd MOLE (800 mg/kg BW), 3rd SeNPs (0.5 mg/kg BW), 4th MOLE-SeNPs (200 μg/kg BW), 5th MEL (700 mg/kg BW), 6th MEL+MOLE, and 7th MEL+MOLE SeNPs. All groups were orally gavaged day after day for 28 days. SeNPs and the colloidal SeNPs were characterized by TEM, SEM, and DLS particle size. SeNPs showed an absorption peak at a wavelength of 530 nm, spherical shape, and an average size between 3.2 and 20 nm. Colloidal SeNPs absorption spectra were recorded between 400 and 700 nm with an average size of 3.3-17 nm. MEL-induced nephropathic alterations represented by a significant increase in serum creatinine, urea, blood urea nitrogen (BUN), renal TNFα, oxidative stress-related indices, and altered the relative mRNA expression of apoptosis-related genes Bax, Caspase-3, Bcl2, Fas, and FasL. MEL-induced array of nephrotoxic morphological changes, and up-regulated immune-expression of proliferating cell nuclear antigen (PCNA) and proliferation-associated nuclear antigen Ki-67. Administration of MOLE or MOLE-SeNPs significantly reversed MEL-induced renal function impairments, oxidative stress, histological alterations, modulation in the relative mRNA expression of apoptosis-related genes, and the immune-expression of renal PCNA and Ki-67. Conclusively, the green-synthesized MOLE-SeNPs and MOLE display nephron-protective properties against MEL-induced murine nephropathy. This study is the first to report these effects which were more pronounced in the MOLE group than the green biosynthesized MOLE-SeNPs conjugate group.

Determining selenium speciation by graphite furnace atomic absorption spectrometry

A straightforward method for measuring two aquatic inorganic species of selenium, selenate, Se(VI), and selenite, Se(IV), was developed in this study. Selenium toxicity and bioaccumulation in food chain are strongly dependent on its speciation. Therefore, it is important to measure selenium species as part of any selenium risk assessment practice. In this method, total selenium was first measured using graphite furnace atomic absorption spectrometry, and then, chemical procedures in the literature were used to reduce selenite, Se(IV), to hydrogen selenide (H₂Se). Total selenium of the same solution was measured again with the analytical instrument after stripping H₂Se from the solution. The difference of total selenium measured gave Se(IV) concentration. The two main species in natural waters are Se(VI) and Se(IV). Therefore, it can be assumed that after removing Se(IV) from the solution, the remaining total selenium is Se(VI). The two inorganic selenium species of (IV) and (VI) in purified waters and synthetic irrigation waters both spiked with Se(VI) and Se(IV) were determined using this method. Recovery of spiked samples in diluted synthetic irrigation water was 97% for Se(VI) and 99% for Se(IV). Detection limits of the method were 0.32 µg L^-1 for Se(VI) and 0.11 µg L^-1 for Se(IV). The advantages of the method developed in this study are that it employs a straightforward simple chemical reaction combined with acidification and stripping, requires only one instrument (graphite furnace atomic absorption spectrometry), and does not require extensive sample pretreatment.

Plant-mediated synthesis of nanoparticles and their antimicrobial activity against phytopathogens

Nanotechnology is an emerging science with a wide array of applications involving the synthesis and manipulation of materials with dimensions in the range of 1-100 nm. Nanotechnological applications include diverse fields such as pharmaceuticals, medicine, the environment, food processing and agriculture. Regarding the latter, applications are mainly focused on plant growth and crop protection against plagues and diseases. In recent years, the biogenic reduction of elements such as Ag, Au, Cu, Cd, Al, Se, Zn, Ce, Ti and Fe with plant extracts has become one of the most accepted techniques for obtaining nanoparticles (NPs), as it is considered an ecological and cost-effective process without the use of chemical contaminants. The objective of this work was to review NPs synthesized by green chemistry using vegetable extracts, as well as their use as antimicrobial agents against phytopathogenic fungi and bacteria. Given the need for alternatives to control and integrate management of phytopathogens, this review is relevant to agriculture, although this technology is barely exploited in this field. © 2020 Society of Chemical Industry.

Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

A newly isolated Bacillus amyloliquefaciens SRB04 for the synthesis of selenium nanoparticles with potential antibacterial properties

The aim of this study was to isolate and characterize marine bacterial strains capable of converting selenite to elemental selenium with the formation of Se nanoparticles (SeNPs). For the first time, a novel marine strain belonging to Bacillus amyloliquefaciens (GenBank accession no. MK392020) was isolated from the coast of the Caspian Sea and characterized based on its ability for transformation of selenite to SeNPs under aerobic conditions. The preliminary formation of SeNPs was confirmed via color changes and the products characterized by UV-Vis spectroscopy. The field-emission scanning electron microscopy (FESEM) together with energy-dispersive X-ray (EDX) analysis showed the presence of the spherical SeNPs on both the surface of the bacterial biomass and in the supernatant solution. Dynamic light scattering (DLS) analysis showed the SeNPs to have an average particle size (Z-average) around 45.4-68.3 nm. The X-ray diffraction (XRD) studies substantiated the amorphous nature of the biosynthesized SeNPs. Fourier-transform infrared spectroscopic (FTIR) studies of the SeNPs indicated typical proteinaceous and lipid-related bands as capping agents on the SeNPs. Different effective parameters corresponding the yield of SeNPs by B. amyloliquefaciens strain SRB04 were optimized under resting cell strategy. Results showed that the optimal process conditions for SeNP production were 2 mM of selenite oxyanion, 20 g/L of cell biomass, and 60 h reaction time. The synthesized SeNPs had a remarkable antibacterial activity on Staphylococcus aureus compared with chloramphenicol as a broad-spectrum antibiotic.

Developments in the study and applications of bacterial transformations of selenium species

Microbial bio-transformations of the essential trace element selenium are now recognized to occur among a wide variety of microorganisms. These transformations are used to convert this element into its assimilated form of selenocysteine, which is at the active center of a number of key enzymes, and to produce selenium nanoparticles, quantum dots, metal selenides, and methylated selenium species that are indispensable for biotechnological and bioremediation applications. The focus of this review is to present the state-of-the-art of all aspects of the investigations into the bacterial transformations of selenium species, and to consider the characterization and biotechnological uses of these transformations and their products.

In vitro evaluation of bone cements impregnated with selenium nanoparticles stabilized by phosphatidylcholine (PC) for application in bone

One of the most common prophylactic techniques to solve prosthetic joint infection (PJI) is incorporation of antibiotics into acrylic bone cement to prevent bacterial colonization and proliferation by providing local antibiotic delivery directly at the implant site. Further, there has been a significant concern over the efficacy of commonly used antibiotics within bone cement due to the rise in multi-drug resistant (MDR) microorganisms. Selenium is an essential trace element that has multiple beneficial effects for human health and its chemotherapeutic action is well known. It was reported that nanostructured selenium enhanced bone cell adhesion and has an increased osteoblast function. In this context, we used the selenium nanoparticles (SeNPs) to improve antibacterial and antioxidant properties of poly (methyl methacrylate) (PMMA) and tri calcium phosphate (TCP)-based bone cements, and to reduce of the infection risk caused by orthopedic implants. As another novelty of this study, we proposed phosphatidylcholine (PC) as a unique and natural stabilizer in the synthesis of selenium nanoparticles. After the structural analysis of the prepared bone cements was performed, in vitro osteointegration and antibacterial efficiency were tested using MC3T-E1 (mouse osteoblastic cell line) and SaOS-2 (human primary osteogenic sarcoma) cell lines, and S. aureus (Gram positive) and E.coli (Gram negative) strains, respectively. More importantly, PC-SeNPs-reinforced bone cements exhibited significant effect against E. coli, compared to S. aureus and a dose-dependent antibacterial activity against both bacterial strains tested. Meanwhile, these bone cements induced the apoptosis of SaOS-2 through increased reactive oxygen species without negatively influencing the viability of the healthy cell line. Furthermore, the obtained confocal images revealed that PC-SeNPs (103.7 ± 0.56 nm) altered the cytoskeletal structure of SaOS-2 owing to SeNPs-induced apoptosis, when MC3T3-E1 cells showed a typical spindle-shaped morphology. Taken together, these results highlighted the potential of PC-SeNPs-doped bone cements as an effective graft material in bone applications.

Selenite reduction by the rhizobacterium Azospirillum brasilense, synthesis of extracellular selenium nanoparticles and their characterisation

Microbial reduction of selenium oxyanions has attracted attention in recent years. In this study, an original and simple method for the synthesis of extracellular selenium nanoparticles (Se NPs) of relatively uniform size has been developed using strains Sp7 and Sp245 of the ubiquitous plant-growth promoting rhizobacterium Azospirillum brasilense, both capable of selenite (SeO₃^2-) reduction. In addition, a reliable purification protocol for the recovery of the Se NPs has been perfected, which could be applied with minor modifications to cultures of other microbial species. Importantly, it was found that, by changing the conditions of bacterial reduction of selenite, extracellularly localised Se NPs can be obtained using bacteria which would otherwise produce intracellular Se NPs. In particular, bacterial cultures grown up to the end of the logarithmic growth phase, washed free of culture medium and then incubated with selenite, were used to obtain extracellular Se NPs. Their sizes depended on the initial selenite concentration (∼25-80 nm in diameter at 50-10 mM selenite, respectively). The Se NPs obtained were characterised by transmission electron microscopy (TEM), dynamic light scattering, as well as Raman and UV-vis spectroscopies. Their zeta potential was found to be negative (ca. minus 21-24 mV). Bacterial selenite reduction was also studied in the presence of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone (CCCP). In this case, TEM indicated the formation only of intracellular selenium crystallites. The data show that the formation of extracellular Se NPs requires normal bacterial metabolic activity, while CCCP evidently blocks the membrane export of Se⁰ nuclei.

Evaluation of effects of selenium nanoparticles on Bacillus subtilis

The present study was performed to characterize of selenium nanoparticles (Nano-Se) which were synthesized by pulsed laser ablation in liquids to obtain the aqueous selenium citrate solution. The study was conducted using bacteriological and electronic-microscopic methods. Transmission electron microscopy (TEM) and spectroscopy analyses demonstrated that nano-selenium particles obtained by the method of selenium ablation had the size of 4–8 nm. UV-Visible Spectrum colloidal solution Nano-Se exhibited absorption maxima at 210 nm. To clarify some effects of the action of Nano-Se on Bacillus subtilis, we investigated the interaction of Nano-Se with B. subtilis IMV B-7392 before and after incubation with Nano-Se, examining TEM images. It has been shown that exposure to B. subtilis IMV B-7392 in the presence of Nano-Se is accompanied by the rapid uptake of Nano-Se by bacterial culture. TEM analysis found that the electron-dense Nano-Se particles were located in the intracellular spaces of B. subtilis IMV B-7392. That does not lead to changes in cultural and morphological characteristics of B. subtilis IMV B-7392. Using TEM, it has been shown that penetration of nanoparticles in the internal compartments is accompanied with transient porosity of the cell membrane of B. subtilis IMV B-7392 without rupturing it. The effective concentration of Nano-Se 0.2 × 10–3 mg/mL was found to increase the yield of biologically active substances of B. subtilis. In order to create probiotic nano-selenium containing products, the nutrient medium of B. subtilis IMV B-7392 was enriched with Nano-Se at 0.2 × 10–3 mg/mL. It was found that particles Nano-Se are non-toxic to the culture and did not exhibit bactericidal or bacteriostatic effects. The experimentally demonstrated ability of B. subtilis to absorb selenium nanoparticles has opened up the possibility of using Nano-Se as suitable drug carriers.

Methyl Selenol as a Precursor in Selenite Reduction to Se/S Species by Methane-Oxidizing Bacteria

Aerobic methane-oxidizing bacteria are ubiquitous in the environment. Two well-characterized strains, Mc. capsulatus (Bath) and Methylosinus trichosporium OB3b, representing gamma- and alphaproteobacterial methanotrophs, respectively, can convert selenite, an environmental pollutant, to volatile selenium compounds and selenium-containing particulates. Both conversions can be harnessed for the bioremediation of selenium pollution using biological or fossil methane as the feedstock, and these organisms could be used to produce selenium-containing particles for food and biotechnological applications. Using an extensive suite of techniques, we identified precursors of selenium nanoparticle formation and also found that these nanoparticles are made up of eight-membered mixed selenium and sulfur rings.

A wide range of microorganisms have been shown to transform selenium-containing oxyanions to reduced forms of the element, particularly selenium-containing nanoparticles. Such reactions are promising for the detoxification of environmental contamination and the production of valuable selenium-containing products, such as nanoparticles for application in biotechnology. It has previously been shown that aerobic methane-oxidizing bacteria, including Methylococcus capsulatus (Bath), are able to perform the methane-driven conversion of selenite (SeO₃²⁻) to selenium-containing nanoparticles and methylated selenium species. Here, the biotransformation of selenite by Mc. capsulatus (Bath) has been studied in detail via a range of imaging, chromatographic, and spectroscopic techniques. The results indicate that the nanoparticles are produced extracellularly and have a composition distinct from that of nanoparticles previously observed from other organisms. The spectroscopic data from the methanotroph-derived nanoparticles are best accounted for by a bulk structure composed primarily of octameric rings in the form Se_{8 −x}S_x with an outer coat of cell-derived biomacromolecules. Among a range of volatile methylated selenium and selenium-sulfur species detected, methyl selenol (CH₃SeH) was found only when selenite was the starting material, although selenium nanoparticles (both biogenic and chemically produced) could be transformed into other methylated selenium species. This result is consistent with methyl selenol being an intermediate in the methanotroph-mediated biotransformation of selenium to all the methylated and particulate products observed.

IMPORTANCE Aerobic methane-oxidizing bacteria are ubiquitous in the environment. Two well-characterized strains, Mc. capsulatus (Bath) and Methylosinus trichosporium OB3b, representing gamma- and alphaproteobacterial methanotrophs, respectively, can convert selenite, an environmental pollutant, to volatile selenium compounds and selenium-containing particulates. Both conversions can be harnessed for the bioremediation of selenium pollution using biological or fossil methane as the feedstock, and these organisms could be used to produce selenium-containing particles for food and biotechnological applications. Using an extensive suite of techniques, we identified precursors of selenium nanoparticle formation and also found that these nanoparticles are made up of eight-membered mixed selenium and sulfur rings.

The Application of Selenium and Copper Nanoparticles Modifies the Biochemical Responses of Tomato Plants under Stress by Alternaria solani

Early blight is a disease that greatly affects Solanaceae, mainly damaging tomato plants, and causing significant economic losses. Although there are methods of biological control, these are very expensive and often their mode of action is slow. Due to this, there is a need to use new techniques that allow a more efficient control of pathogens. Nanotechnology is a new alternative to solve these problems, allowing the creation of new tools for the treatment of diseases in plants, as well as the control of pathogens. The aim of the present investigation was to evaluate the foliar application of selenium and copper in the form of nanoparticles in a tomato crop infested by Alternaria solani. The severity of Alternaria solani, agronomic variables of the tomato crop, and the changes in the enzymatic and non-enzymatic antioxidant compounds were evaluated. The joint application of Se and Cu nanoparticles decreases the severity of this pathogen in tomato plants. Moreover, high doses generated an induction of the activity of the enzymes superoxide dismutase, ascorbate peroxidase, glutathione peroxidase (GPX) and phenylalanine ammonia lyase in the leaves, and the enzyme GPX in the fruit. Regarding non-enzymatic compounds in the leaves, chlorophyll a, b, and totals were increased, whereas vitamin C, glutathione, phenols, and flavonoids were increased in fruits. The application of nanoparticles generated beneficial effects by increasing the enzymatic and non-enzymatic compounds and decreasing the severity of Alternaria solani in tomato plants.

Overview of microbes based fabricated biogenic nanoparticles for water and wastewater treatment

Treatment of toxic and emerging pollutants (T&EPs) is increasing the threats to the survival of conventional wastewater treatment (WWTs) technologies. The high installation and operational costs of advanced treatment technologies have shifted the research interest to the development of economical and reliable technology for management of T&EPs. Thus, recently biogenic nanoparticles (BNPs) fabricated using microbes/microorganisms are getting tremendous research interest due to their unique properties (i.e. high specific surface area, desired morphology, catalytic reactivity) for the biodegradation and biosorption of T&EPs. In addition, BNPs can be manufactured using metal contaminated water which indicates a hidden potential for resource recovery and utilization. Therefore, the present study discusses the adsorptive and catalytic performance of BNPs in the removal of T&EPs from water (W) and wastewater (WW). In addition, inspired by the superior performance of BNPs in advance WWT, a model of BNPs based WWT resource recovery and utilization process is also proposed. Finally, main issues i.e. mass production, leaching, poisoning/toxicity, regeneration, reusability and fabrication costs and process optimization are discussed which are main hinders in the transfer of BNPs based WWT technologies from laboratory to commercial scale.

Physical-Chemical Properties of Biogenic Selenium Nanostructures Produced by Stenotrophomonas maltophilia SeITE02 and Ochrobactrum sp. MPV1

Stenotrophomonas maltophilia SeITE02 and Ochrobactrum sp. MPV1 were isolated from the rhizosphere soil of the selenium-hyperaccumulator legume Astragalus bisulcatus and waste material from a dumping site for roasted pyrites, respectively. Here, these bacterial strains were studied as cell factories to generate selenium-nanostructures (SeNS) under metabolically controlled growth conditions. Thus, a defined medium (DM) containing either glucose or pyruvate as carbon and energy source along with selenite () was tested to evaluate bacterial growth, oxyanion bioconversion and changes occurring in SeNS features with respect to those generated by these strains grown on rich media. Transmission electron microscopy (TEM) images show extra- or intra-cellular emergence of SeNS in SeITE02 or MPV1 respectively, revealing the presence of two distinct biological routes of SeNS biogenesis. Indeed, the stress exerted by upon SeITE02 cells triggered the production of membrane vesicles (MVs), which surrounded Se-nanoparticles (SeNPs_{SeITE02-G_e} and SeNPs_{SeITE02-P_e} with average diameter of 179 ± 56 and 208 ± 60 nm, respectively), as highlighted by TEM and scanning electron microscopy (SEM), strongly suggesting that MVs might play a crucial role in the excreting mechanism of the SeNPs in the extracellular environment. On the other hand, MPV1 strain biosynthesized intracellular inclusions likely containing hydrophobic storage compounds and SeNPs (123 ± 32 nm) under pyruvate conditioning, while the growth on glucose as the only source of carbon and energy led to the production of a mixed population of intracellular SeNPs (118 ± 36 nm) and nanorods (SeNRs; average length of 324 ± 89). SEM, fluorescence spectroscopy, and confocal laser scanning microscopy (CLSM) revealed that the biogenic SeNS were enclosed in an organic material containing proteins and amphiphilic molecules, possibly responsible for the high thermodynamic stability of these nanomaterials. Finally, the biogenic SeNS extracts were photoluminescent upon excitation ranging from 380 to 530 nm, whose degree of fluorescence emission (λ_em = 416–640 nm) was comparable to that from chemically synthesized SeNPs with L-cysteine (L-cys SeNPs). This study offers novel insights into the formation, localization, and release of biogenic SeNS generated by two different Gram-negative bacterial strains under aerobic and metabolically controlled growth conditions. The work strengthens the possibility of using these bacterial isolates as eco-friendly biocatalysts to produce high quality SeNS targeted to possible biomedical applications and other biotechnological purposes.

Synthesis and Antibacterial Activity of Metal(loid) Nanostructures by Environmental Multi-Metal(loid) Resistant Bacteria and Metal(loid)-Reducing Flavoproteins

Microbes are suitable candidates to recover and decontaminate different environments from soluble metal ions, either via reduction or precipitation to generate insoluble, non-toxic derivatives. In general, microorganisms reduce toxic metal ions generating nanostructures (NS), which display great applicability in biotechnological processes. Since the molecular bases of bacterial reduction are still unknown, the search for new -environmentally safe and less expensive- methods to synthesize NS have made biological systems attractive candidates. Here, 47 microorganisms isolated from a number of environmental samples were analyzed for their tolerance or sensitivity to 19 metal(loid)s. Ten of them were highly tolerant to some of them and were assessed for their ability to reduce these toxicants in vitro. All isolates were analyzed by 16S rRNA gene sequencing, fatty acids composition, biochemical tests and electron microscopy. Results showed that they belong to the Enterobacter, Staphylococcus, Acinetobacter, and Exiguobacterium genera. Most strains displayed metal(loid)-reducing activity using either NADH or NADPH as cofactor. While Acinetobacter schindleri showed the highest tellurite ( TeO32- ) and tetrachloro aurate ( AuCl4- ) reducing activity, Staphylococcus sciuri and Exiguobacterium acetylicum exhibited selenite ( SeO32- ) and silver (Ag⁺) reducing activity, respectively. Based on these results, we used these bacteria to synthetize, in vivo and in vitro Te, Se, Au, and Ag-containing nanostructures. On the other hand, we also used purified E. cloacae glutathione reductase to synthesize in vitro Te-, Ag-, and Se-containing NS, whose morphology, size, composition, and chemical composition were evaluated. Finally, we assessed the putative anti-bacterial activity exhibited by the in vitro synthesized NS: Te-containing NS were more effective than Au-NS in inhibiting Escherichia coli and Listeria monocytogenes growth. Aerobically synthesized TeNS using MF09 crude extracts showed MICs of 45- and 66- μg/ml for E. coli and L. monocytogenes, respectively. Similar MIC values (40 and 82 μg/ml, respectively) were observed for TeNS generated using crude extracts from gorA-overexpressing E. coli. In turn, AuNS MICs for E. coli and L. monocytogenes were 64- and 68- μg/ml, respectively.

Free-standing red phosphorous/silver sponge monolith as an efficient and easily recyclable macroscale photocatalyst for organic pollutant degradation under visible light irradiation

Traditional nano-sized photocatalysts in powdery form suffer from difficulties in recyclability, and have to be immobilized before practical applications. In this study, red phosphorous/silver (red P/Ag) sponge monolith was discovered to be a new free-standing macroscale photocatalyst, which was fabricated by a one-pot hydrothermal method without using any organic surfactants or templates for the first time. The elemental red P not only functioned as a reducing agent in the formation of Ag sponge monolith during the synthesis processes, but also as the active photocatalyst in-situ immobilized onto the Ag sponge. The as-prepared red P/Ag sponge monolith showed enhanced photocatalytic activity than that of traditional pure powdery red P by a factor of 3.1 times for organic pollutants (i.e. Rhodamine 6G, phenol) degradation under visible light irradiation. The enhancement was mainly attributed to the function of Ag sponge served as good electron sink to trap photo-generated electrons. More importantly, such free-standing macroscale photocatalyst can be easily recycled without activity deterioration. As a proof of concept, this work provides new insights into not only for the development of red P-based elemental photocatalysts, but also for the one-pot fabrication of novel free-standing macroscale materials with excellent photocatalytic activity for practical environmental applications.

Biosynthesis of selenium-nanoparticles and -nanorods as a product of selenite bioconversion by the aerobic bacterium Rhodococcus aetherivorans BCP1

The wide anthropogenic use of selenium compounds represents the major source of selenium pollution worldwide, causing environmental issues and health concerns. Microbe-based strategies for metal removal/recovery have received increasing interest thanks to the association of the microbial ability to detoxify toxic metal/metalloid polluted environments with the production of nanomaterials. This study investigates the tolerance and the bioconversion of selenite (SeO₃^2-) by the aerobically grown Actinomycete Rhodococcus aetherivorans BCP1 in association with its ability to produce selenium nanoparticles and nanorods (SeNPs and SeNRs). The BCP1 strain showed high tolerance towards SeO₃^2- with a Minimal Inhibitory Concentration (MIC) of 500mM. The bioconversion of SeO₃^2- was evaluated considering two different physiological states of the BCP1 strain, i.e. unconditioned and/or conditioned cells, which correspond to cells exposed for the first time or after re-inoculation in fresh medium to either 0.5 or 2mM of Na₂SeO₃, respectively. SeO₃^2- bioconversion was higher for conditioned grown cells compared to the unconditioned ones. Selenium nanostructures appeared polydisperse and not aggregated, as detected by electron microscopy, being embedded in an organic coating likely responsible for their stability, as suggested by the physical-chemical characterization. The production of smaller and/or larger SeNPs was influenced by the initial concentration of provided precursor, which resulted in the growth of longer and/or shorter SeNRs, respectively. The strong ability to tolerate high SeO₃^2- concentrations coupled with SeNP and SeNR biosynthesis highlights promising new applications of Rhodococcus aetherivorans BCP1 as cell factory to produce stable Se-nanostructures, whose suitability might be exploited for biotechnology purposes.

Biogenic selenium and its hepatoprotective activity

Elemental selenium nanoparticles (SeNPs) have multiple biological activities. In this study, we investigated the protective effects of biogenic SeNPs (BioSeNPs) on CCl₄-induced liver damage in mice. The results showed that: (i) when compared to sodium selenite (SS), BioSeNPs has a similar tissue distribution after intragastrical administration to mice; (ii) BioSeNPs and SS showed comparable efficacy in increasing the activities of glutathione peroxidase and thioredoxin reductase in liver cell lines, mice blood and liver; (iii) pretreatment with BioSeNPs inhibiting the elevation of activities of various enzymes significantly which included aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase and liver lipid peroxide (p < 0.05 or p < 0.01) in CCl₄-treated mice; (iv) activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) were significantly increased (p < 0.05 or p < 0.01) after a pretreatment with BioSeNPs in CCl₄-treated mice; (v) histopathological damages in the liver from CCl₄-treated mice were ameliorated by a pretreatment with BioSeNPs. In conclusion, these results have shown that BioSeNPs is able to protect the liver from CCl₄-induced hepatic damage via increasing the antioxidant capacity and inhibiting oxidative damage. BioSeNPs may have the potential to be used as a trace element food supplement inducing antioxidant bioactivities.

Proteins in microbial synthesis of selenium nanoparticles

Biogenic formation of nano-sized particles composed of various materials (in particular, selenium) by live microorganisms is widespread in nature. This phenomenon has been increasingly attracting the attention of researchers over the last decade not only owing to a range of diverse applications of such nanoparticles (NPs) in nanobiotechnology, but also because of the specificity of methodologies and mechanisms of NPs formation related to "green synthesis". In this mini-review, recent data are discussed on the multifaceted role of proteins in the processes of microbial reduction of selenium oxyanions and the formation of Se NPs. Besides the involvement of proteins in reducing selenites and selenates, their participation in the microbially driven growth and stabilisation of Se NPs is analysed, which results in the formation of unique nanostructured materials differing from those obtained chemically. This mini-review is thus focussed on proteins involved in microbial synthesis of Se NPs and on instrumental analysis of these processes and their products (biogenic nanostructured selenium particles functionalised by a surface-capping layer of various biomacromolecules).

Aerobic biogenesis of selenium nanoparticles by Enterobacter cloacae Z0206 as a consequence of fumarate reductase mediated selenite reduction

In the present study, we examined the ability of Enterobacter cloacae Z0206 to reduce toxic sodium selenite and mechanism of this process. E. cloacae Z0206 was found to completely reduce up to 10 mM selenite to elemental selenium (Se°) and form selenium nanoparticles (SeNPs) under aerobic conditions. The selenite reducing effector of E. cloacae Z0206 cell was to be a membrane-localized enzyme. iTRAQ proteomic analysis revealed that selenite induced a significant increase in the expression of fumarate reductase. Furthermore, the addition of fumarate to the broth and knockout of fumarate reductase (frd) both significantly decreased the selenite reduction rate, which revealed a previously unrecognized role of E. cloacae Z0206 fumarate reductase in selenite reduction. In contrast, glutathione-mediated Painter-type reactions were not the main pathway of selenite reducing. In conclusion, E. cloacae Z0206 effectively reduced selenite to Se° using fumarate reductase and formed SeNPs; this capability may be employed to develop a bioreactor for treating Se pollution and for the biosynthesis of SeNPs in the future.

Sponge-supported synthesis of colloidal selenium nanospheres

With increasing biomedical and engineering applications of selenium nanospheres (SeNS), new efficient methods are needed for the synthesis and long-term preservation of these nanomaterials. Currently, SeNS are mostly produced through the biosynthesis route using microorganisms or by using wet chemical reduction, both of which have several limitations in terms of nanoparticle size, yield, production time and long-term stability of the nanoparticles. Here, we introduce a novel approach for rapid synthesis and long-term preservation of SeNS on a solid microporous support by combining a mild hydrothermal process with chemical reduction. By using a natural sponge as a solid three-dimensional matrix for nanoparticle growth, we have synthesized highly monodisperse spherical nanoparticles with a wide size range (10-1000 nm) and extremely high yield in a relatively short period of time (1 h). Additionally, the synthesized SeNS can be stored and retrieved whenever needed by simply washing the sponge in water. Keeping the nanospheres in the support offers remarkable long-term stability as particles left on the sponge preserve their morphological and colloidal characteristics even after eight months of storage. Furthermore, this work reveals that SeNS can be used for efficient mercury capture from contaminated waters with a record-breaking mercury removal capacity of 1900 mg g^-1.

Protective role of biogenic selenium nanoparticles in immunological and oxidative stress generated by enrofloxacin in broiler chicken

Presently most bacteria are becoming antibiotic resistant. Due to this there is a deficiency of potent antibiotics, therefore we have to preserve and improve the efficiency of existing antibiotics by mitigating the side effects. Enrofloxacin (EFX) is an important antimicrobial used in veterinary practice but it is known to exert immune suppression antioxidant stress. In the present study, we report on: (a) the biosynthesis of selenium nanoparticles (Se NPs), and (b) their protective effect in reducing adverse effects of EFX on broiler chicken. A potent bacterial strain, isolated from farm soil, has been identified as Pantoea agglomerans (GenBank: KU500622). It tolerates a high concentration of selenium dioxide (9 mM) and produces Se NPs under aerobic conditions. The obtained Se NPs are amorphous in structure and spherical in shape with sizes of less than 100 nm. The activity of cellular, humoral immune response and enzymatic and non-enzymatic antioxidants, has significantly been decreased as a result of EFX treatment. We investigated that Se NP supplementation greatly restores these values towards the control, and to even higher than those of the control. Adverse effects of EFX are prevented by simultaneous exposure to Se NPs (0.6 mg per kg of feed) in the diet of poultry chicken.

An eco-friendly physicocultural-based rapid synthesis of selenium nanoparticles

A rapid synthesis of stable and smaller sized Se NPs was achieved in tryptic soya medium maintained at pH ∼9, temperature ∼50 °C, and a 9 mM Se oxyion concentration.