Isolation, characterization, and genomic analysis of vB_PaeS_TUMS_P81, a lytic bacteriophage against Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic human pathogen that can lead to nosocomial infections which are in turn life threatening. The increase in antibiotic resistance, at an alarming rate, has resulted in a pressing need for alternative therapeutic approaches such as phage therapy, which hold promise according to several studies. This study featured the isolation and characterization of vB_PaeS_TUMS_P81, a new lytic Pseudomonas phage. The whole-genome sequencing indicated that it has a genome of 73,167 bp containing 93 predicted coding sequences. Genes involved in virulence or lysogeny pathway were nowhere to be found in the genome, so it is potentially safe when it comes to therapeutic applications. Genomic and phylogenetic analysis indicated that vB_PaeS_TUMS_P81 is a member of the genus Litunavirus, belonging to Schitoviridae family. The present study lays the groundwork for further research on treatment of P. aeruginosa infections.

Isolation, characterization, and genomic analysis of vB_PaeP_TUMS_P121, a new lytic bacteriophage infecting Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic human pathogen that can cause life-threatening nosocomial infections. The alarming increase in antibiotic resistance has led to an urgent need for alternative therapeutic approaches, such as phage therapy, which has shown promising results in many studies. In this study, P121, a new lytic Pseudomonas phage, was isolated and characterized. Whole-genome sequencing showed that it has a genome of 73,001 bp that contains 91 predicted coding sequences. No genes involved in virulence or lysogeny were found in the genome, thus making it potentially safe for therapeutic applications. Genomic and phylogenetic analysis indicated that P121 is a member of the genus Litunavirus, family Schitoviridae. The present study provides some basic information for further research on treatment of P. aeruginosa infections.

PerioVax3, a key antigenic determinant with immunoprotective potential against periodontal pathogen.

Treponema (T.) denticola is one of the key etiological agents in the development of periodontitis. The major outer sheath protein (Msp) of T. denticola has been shown to mediate pathogenesis and to facilitate adhesion of T. denticola to mucosal surfaces. This study aimed to find short polypeptides in the amino acid sequence of Msp which may be immunogenic and might elicit protective antisera against T. denticola. The complete msp sequence was divided into six fragments and the corresponding genes were cloned and expressed. Antisera against the polypeptides were raised in rabbits and fragment 3 (F3), hereinafter called PerioVax3 was the most potent fragment of the Msp in terms of yielding high titer antiserum. An adhesion assay was done to examine the inhibitory effects of antisera on the attachment of T. denticola to human gingival fibroblasts (HGFs) and human fibronectin. Antiserum against PerioVax3 significantly inhibited attachment of T. denticola to the substratum. Also, antiserum against PerioVax3 inhibited detachment of HGFs upon T. denticola exposure. To begin examining the clinical relevance of this work, blood samples from 12 sever periodontitis patients were collected and the sera were used in western blotting against the recombinant polypeptides. Periodontitis patient antisera exclusively detected PerioVax3 in western blotting. The data suggest that PerioVax3 carries epitopes that may trigger humoral immunity against T. denticola, which may protect against its adhesion functions. The complexity of periodontitis suggests that PerioVax3 may be considered for testing as a component of an experimental multivalent periodontal vaccine in further preclinical and clinical studies.

Adjuvant Effect of Biogenic Selenium Nanoparticles Improves the Immune Responses and Survival of Mice Receiving 4T1 Cell Antigens as Vaccine in Breast Cancer Murine Model.

The modification of tumor-associated antigen-based vaccine to elicit a more robust immune response has been addressed in several ways. In the present work, we aimed to investigate the immunomodulatory effect of selenium nanoparticles as an immunoadjuvant in formulation of a tumor-associated antigen-based vaccine in a preventive form. Fortyfive female inbred BALB/c mice five-to-seven weeks old were used and divided into three groups of test and control, each containing fifteen mice. Group one injected by PBS and used as a control. Group two injected by breast tumor cell lysate alone as vaccine. Group three injected by SeNPs with tumor cell lysate as vaccine. All injections were carried out on day fourteen, twentyone and twentyeight of the study. Tumor induction was done at day thirty. Twenty days after tumor induction serum samples were gathered to measure the cytokine assay. Tumor growth and weight of mice as well as delayed type hyper sensitivity (DTH) response were monitored during the study. Results of the present work showed a significant increase in the level of serum IFN-γ, IL-2, IL-12 and decreased TGF-ß in SeNPs/vaccine injected mice as well as lower tumor volume, more potent DTH responses and longer survival rate in comparison to control and tumor lysate vaccine. Taken together, it can be deduced from this work that SeNPs can be considered as an adjuvant in vaccine in triggering robust immune response against breast cancer. But further evaluations are still needed to find the best formula for this agent in antitumor vaccines.

Enzymatic dual-faced Janus structures based on the hierarchical organic-inorganic hybrid matrix for an effective bioremoval and detoxification of reactive blue-19.

A novel, dual-faced, and hierarchical type of Janus hybrid structures (JHSs) was assembled through an in situ growing of lipase@cobalt phosphate sheets on the laccase@copper phosphate sponge-like structures. The chemical and structural information of prepared JHSs was investigated by Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The catalytic activity, storage stability, and reusability of JHSs were then investigated. The SEM-EDX analysis clearly confirmed the asymmetric morphology of the fabricated JHSs with two distinct metal distributions. Under optimized synthesis conditions, the prepared JHSs showed 97.8 % and 100 % of laccase and lipase activity, respectively. Compared to the free biocatalysts, the immobilization resulted in ~ a 2-fold increase in laccase and lipase stability at temperatures of >40 °C. The fabricated JHSs maintained 61 % and 90 % of their original laccase and lipase activity upon 12 successive repetition cycles. Up to 80 % of Reactive Blue-19 (RB-19), an anthraquinone-based vinyl sulphone dye, was removed after 5 h treatment with the prepared JHSs (50 % higher than the free forms of laccase and lipase). The dye removal data fitted very well on the pseudo-second-order kinetic model with a rate constant of 0.8 g mg-1 h-1. Following the bioremoval process, bacterial toxicity also decreased by about 70 %. Therefore, the prepared JHSs provide a facile and sustainable approach for the decolorization, biotransformation, and detoxification of RB-19 by integrating enzymatic oxidation and hydrolysis.

Decoding the Structure-Function Relationship of the Muramidase Domain in E. coli O157.H7 Bacteriophage Endolysin: A Potential Building Block for Chimeric Enzybiotics.

Bacteriophage endolysins are potential alternatives to conventional antibiotics for treating multidrug-resistant gram-negative bacterial infections. However, their structure-function relationships are poorly understood, hindering their optimization and application. In this study, we focused on the individual functionality of the C-terminal muramidase domain of Gp127, a modular endolysin from E. coli O157:H7 bacteriophage PhaxI. This domain is responsible for the enzymatic activity, whereas the N-terminal domain binds to the bacterial cell wall. Through protein modeling, docking experiments, and molecular dynamics simulations, we investigated the activity, stability, and interactions of the isolated C-terminal domain with its ligand. We also assessed its expression, solubility, toxicity, and lytic activity using the experimental data. Our results revealed that the C-terminal domain exhibits high activity and toxicity when tested individually, and its expression is regulated in different hosts to prevent self-destruction. Furthermore, we validated the muralytic activity of the purified refolded protein by zymography and standardized assays. These findings challenge the need for the N-terminal binding domain to arrange the active site and adjust the gap between crucial residues for peptidoglycan cleavage. Our study shed light on the three-dimensional structure and functionality of muramidase endolysins, thereby enriching the existing knowledge pool and laying a foundation for accurate in silico modeling and the informed design of next-generation enzybiotic treatments.

Isolation, characterization and complete genome sequence of PhaxI: a phage of Escherichia coli O157 : H7.

Bacteriophages are considered as promising biological agents for the control of infectious diseases. Sequencing of their genomes can ascertain the absence of antibiotic resistance, toxin or virulence genes. The anti-O157 : H7 coliphage, PhaxI, was isolated from a sewage sample in Iran. Morphological studies by transmission electron microscopy showed that it has an icosahedral capsid of 85-86 nm and a contractile tail of 115×15 nm. PhaxI contains dsDNA composed of 156 628 nt with a G+C content of 44.5 mol% that encodes 209 putative proteins. In MS analysis of phage particles, 92 structural proteins were identified. PhaxI lyses Escherichia coli O157 : H7 in Luria-Bertani medium and milk, has an eclipse period of 20 min and a latent period of 40 min, and has a burst size of about 420 particles per cell. PhaxI is a member of the genus 'Viunalikevirus' of the family Myoviridae and is specific for E. coli O157 : H7.

Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles.

Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential.

Biochemical characterization of an extracellular polyextremophilic α-amylase from the halophilic archaeon Halorubrum xinjiangense.

An extracellular haloalkaliphilic thermostable α-amylase producing archaeon was isolated from the saltwater Lake Urmia and identified as Halorubrum xinjiangense on the basis of morphological, biochemical, and molecular properties. The enzyme was purified to an electrophoretically homogenous state by 80 % cold ethanol precipitation, followed by affinity chromatography. The concentrated pure amylase was eluted as a single peak on fast protein liquid chromatography. The molecular mass of the purified enzyme was about 60 kDa, with a pI value of 4.5. Maximum amylase activity was at 4 M NaCl or 4.5 M KCl, 70 °C, and pH 8.5. The K m and V max of the enzyme were determined as 3.8 mg ml(-1) and 12.4 U mg(-1), respectively. The pure amylase was stable in the presence of SDS, detergents, and organic solvents. In addition, the enzyme (20 U) hydrolyzed 69 % of the wheat starch after a 2-h incubation at 70 °C in an aqueous/hexadecane two-phase system.

Preparation and optimization of acetaminophen nanosuspension through nanoprecipitation using microfluidic devices: an artificial neural networks study.

The purpose of this study was to find an artificial neural networks model for determining major factors impacting the stability of an acetaminophen nanosuspansion that was prepared using nanoprecipitation in microfluidic reactors. Four variables, namely concentration of surfactant, solvent and antisolvent flow rate and solvent temperature were used as input variables and time of sedimentation of nanoparticles was considered as output variable. The particle size of optimized formulation was measured by transmission electron microscope and dynamic light scattering. Comparing the 3D graphs from the model showed that antisolvent flow rate and temperature have direct relation with time of sedimentation, whereas solvent flow rate generally has reverse relation with the time of sedimentation. Concentration of surfactant was found to be the most important factor in determining the stability of nanosuspension.

Acute and subacute toxicity of novel biogenic selenium nanoparticles in mice.

CONTEXT: In the present investigation, acute and subacute toxicity of the biogenic Se nanoparticles (Se NPs) has been reported. OBJECTIVE: To characterize the Se NPs produced by a bacterium species and to evaluate their toxicity and impact on clinical chemistry and hematological parameters of NMRI mice. MATERIALS AND METHODS: The Se NPs were prepared by Bacillus sp. MSh-1 in a culture medium containing SeO(2) (1.26 mM) and their physiochemical properties investigated using TEM, XRD and FT-IR. The LD(50) of Se NPs and SeO(2) were determined and the subacute toxicity evaluated by orally administration of 0, 2.5, 5, 10 and 20 mg kg(-1) of Se NPs to male mice for 14 consecutive days. Parameters of blood cells, AST, ALT, ALP, creatinine, BUN, cholesterol, bilirubin, triglyceride and CPK were experimentally measured. RESULTS: The XRD and TEM analyses showed that the spherical NPs were amorphous, in the size range of 80-220 nm. The toxicological evaluation showed that the LD(50) values of SeO(2) and Se NPs were 7.3 and 198.1 mg kg(-1), respectively. No biochemical changes were observed from the administration of 2.5, 5 and 10 mg kg(-1) of Se NPs, but a dose of 20 mg kg(-1) was accompanied with signs of toxicity including lower body weight and changes in clinical chemistry and hematological parameters. CONCLUSION: The biogenic Se NPs were less toxic than synthetic Se NPs and much less (26-fold) toxic than the SeO(2), which demonstrates the important role of Bacillus sp. MSh-1 in conversion of a highly toxic Se compound to the less toxic Se NPs.

Selenium nanoparticle-enriched Lactobacillus brevis causes more efficient immune responses in vivo and reduces the liver metastasis in metastatic form of mouse breast cancer.

BACKGROUND AND THE PURPOSE OF THE STUDY: Selenium enriched Lactobacillus has been reported as an immunostimulatory agent which can be used to increase the life span of cancer bearing animals. Lactic acid bacteria can reduce selenium ions to elemental selenium nanoparticles (SeNPs) and deposit them in intracellular spaces. In this strategy two known immunostimulators, lactic acid bacteria (LAB) and SeNPs, are concomitantly administered for enhancing of immune responses in cancer bearing mice. METHODS: Forty five female inbred BALB/c mice were divided into three groups of tests and control, each containing 15 mice. Test mice were orally administered with SeNP-enriched Lactobacillus brevis or Lactobacillus brevis alone for 3 weeks before tumor induction. After that the administration was followed in three cycles of seven days on/three days off. Control group received phosphate buffer saline (PBS) at same condition. During the study the tumor growth was monitored using caliper method. At the end of study the spleen cell culture was carried out for both NK cytotoxicity assay and cytokines measurement. Delayed type hypersensitivity (DTH) responses were also assayed after 72h of tumor antigen recall. Serum lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) levels were measured, the livers of mice were removed and prepared for histopathological analysis. RESULTS: High level of IFN-γ and IL-17 besides the significant raised in NK cytotoxicity and DTH responses were observed in SeNP-enriched L. brevis administered mice and the extended life span and decrease in the tumor metastasis to liver were also recorded in this group compared to the control mice or L.brevis alone administered mice. CONCLUSION: Our results suggested that the better prognosis could be achieved by oral administration of SeNP-enriched L. brevis in highly metastatic breast cancer mice model.

Isolation, characterization, and genome analysis of a broad host range Salmonella phage vB_SenS_TUMS_E4: a candidate bacteriophage for biocontrol.

Salmonella enteritidis is one of the most important foodborne pathogens that cause numerous outbreaks worldwide. Some strains of Salmonella have become progressively resistant to antibiotics, so they could represent a critical threat to public health and have led to the use of alternative therapeutic approaches like phage therapy. In this study, a lytic phage, vB_SenS_TUMS_E4 (E4), was isolated from poultry effluent and characterized to evaluate its potential and efficacy for bio-controlling S. enteritidis in foods. Transmission electron microscopy revealed that E4 has a siphovirus morphotype, with an isometric head and non-contractile tail. Determining the host range showed that this phage can effectively infect different motile as well as non-motile Salmonella enterica serovars. The biological characteristics of E4 showed that it has a short latent period of about 15 min and a large burst size of 287 PFU/cell, and is also significantly stable in a broad range of pHs and temperatures. The E4 whole genome contains 43,018 bp and encodes 60 coding sequences (CDSs) but no tRNA genes. Bioinformatics analysis revealed that the genome of E4 lacks any genes related to lysogeny behavior, antibiotic resistance, toxins, or virulence factors. The efficacy of phage E4 as a bio-control agent was assessed in various foodstuffs inoculated with S. enteritidis at 4°C and 25°C, and the resulting data indicated that it could eradicate S. enteritidis after a very short time of 15 min. The findings of the present study showed that E4 is a hopeful candidate as a bio-control agent against S. enteritidis and has the potential to be used in various foodstuffs.

The use of artificial neural networks for optimizing polydispersity index (PDI) in nanoprecipitation process of acetaminophen in microfluidic devices.

Artificial neural networks (ANNs) were used in this study to determine factors that control the polydispersity index (PDI) in an acetaminophen nanosuspension which was prepared using nanoprecipitation in microfluidic devices. The PDI of prepared formulations was measured by dynamic light scattering. Afterwards, the ANNs were applied to model the data. Four independent variables, namely, surfactant concentration, solvent temperature, and flow rate of solvent and antisolvent were considered as input variables, and the PDI of acetaminophen nanosuspension was taken as the output variable. The response surfaces, generated as 3D graphs after modeling, were used to survey the interactions happening between the input variables and the output variable. Comparison of the response surfaces indicated that the antisolvent flow rate and the solvent temperature have reverse effect on the PDI, whereas solvent flow rate has direct relation with PDI. Also, the effect of the concentration of the surfactant on the PDI was found to be indirect and less influential. Overall, it was found that minimum PDI may be obtained at high values of antisolvent flow rate and solvent temperature, while the solvent flow rate should be kept to a minimum.

Wound healing and anti-inflammatory effects of bacterial cellulose coated with Pistacia atlantica fruit oil.

BACKGROUND: Biological activities of Pistacia atlantica have been investigated for few decades. The fruit oil of the plant has been used for treatment of wounds, inflammation, and other ailments in Traditional Persian Medicine (TPM). OBJECTIVES: The main objectives of this study were to analyze the chemical composition of Pistacia atlantica fruit oil and to study wound healing and anti-inflammatory effects of oil-absorbed bacterial cellulose in an in vivo burn wound model. METHOD: Bacterial cellulose membrane was prepared from Kombucha culture and Fourier-transform infrared was used to characterize the bacterial cellulose. Cold press technique was used to obtain Pistacia atlantica fruit oil and the chemical composition was analyzed by gas chromatography. Bacterial cellulose membrane was impregnated with the Pistacia atlantica fruit oil. Pistacia atlantica hydrogel was prepared using specific Carbopol. Burn wound model was used to evaluate in vivo wound healing and anti-inflammatory effects of the wound dressings containing either silver sulfadiazine as positive control, Pistacia atlantica hydrogel or bacterial cellulose membrane coated with the Pistacia atlantica fruit oil. Blank dressing was used as negative control. RESULTS: FT-IR analysis showed that the structure of the bacterial cellulose corresponded with the standard FT-IR spectrum. The major components of Pistacia atlantica fruit oil constituted linoleic acid (38.1%), oleic acid (36.9%) and stearic acid (3.8%). Histological analysis showed that bacterial cellulose coated with fruit oil significantly decreased the number of neutrophils as a measure of inflammation compared to either negative control or positive control (p < 0.05). Wound closure occurred faster in the treated group with fruit oil-coated bacterial cellulose compared to the other treatments (p < 0.05). CONCLUSION: The results showed that bacterial cellulose coated with Pistacia atlantica fruit oil can be a potential bio-safe dressing for wound management.

Amelioration of experimental colitis by a novel nanoselenium-silymarin mixture.

BACKGROUND: Silymarin has intracellular antioxidant property and inhibits activation of nuclear factor-κB (NF-κB) in low concentrations and reduces tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-6 levels, cyclooxygenase (COX), and angiogenesis. Selenium is one of the necessary trace element nutrients for human and animals. Selenium nanoparticles (nano-Se) have more bioavailability with less toxicity. AIMS: To investigate the combination effect of silymarin and nano-Se on inhibition of NF-κB, proinflammatory cytokines, and oxidative stress biomarkers in the experimental colitis. METHODS: Trinitrobenzene sulfonic acid (TNBS) was used to induce colitis. After TNBS instillation, rats were distributed into six groups, containing silymarin and nano-Se alone or in combination, dexamethasone, negative control with no treatment and the last one was normal sham rats. All drugs were administered for 7 days. Colon samples were scored macroscopically and microscopically. The levels of activated NF-κB, IL-1ß, TNF-α, myeloperoxidase (MPO), lipid peroxidation, protein carbonyl (PC), and the antioxidant power of the colon homogenates were determined. RESULT: A significant decrease in NF-κB activity in treated groups was observed. The levels of TNF-α, IL-1ß, MPO, lipid peroxidation, and PC were reduced and an improvement in antioxidant power of treated groups was seen. Combination of silymarin and nano-Se were more effective than each one alone in improvement of NF-κB, TNF-α, antioxidant power, and lipid peroxidation values, although this difference was not significant in other factors. CONCLUSION: Co-administration of silymarin and nano-Se with a good antioxidant profile and inhibition of NF-κB is a possible candidate for better management of inflammatory bowel disease.

Comparison of Cytokine Expression in Human PBMCs Stimulated with Normal and Heat-Shocked Lactobacillus plantarum Cell Lysate.

Regulation of immune responses is among the beneficial effects of probiotic bacteria on human health. In this study, we aim to investigate the effect of normal and heat-shocked Lactobacillus plantarum PTCC 1058 cell lysate on cytokine expression by human PBMCs. The mid-exponential phase L. plantarum (108 CFU/mL) were used to prepare cell lysate. Isolated PBMCs were stimulated with 100 µg/mL of each normal and heat-shocked L. plantarum cell lysate for 72 h. Non-stimulated PBMCs were also evaluated as negative control. The mRNA expression of IL-6, IL-10, IFN-É£, TNF-α, and TGF-ß genes was determined by quantitative RT-PCR amplification of total RNA extracted from PBMCs. Both types of cell lysate were able to increase pro-inflammatory cytokines and decrease anti-inflammatory cytokines. However, this effect was significantly stronger in heat-shocked cell lysate-treated PBMCs. Moreover, comparison of IFN-É£/IL-10, IFN-É£/TGF-ß, IL-6/IL-10, IL-6/TGF-ß, and TNF-α/IL-10 ratios in both conditions demonstrated that in the heat-shocked group, all of the above ratios were significantly higher than normal lysate treatment (p˂0.001), suggesting that heat-shocked probiotics are a potent inducer of the immune system in comparison to intact probiotics. Regarding these results, it may be possible to develop a new postbiotic product for the stimulation of immune responses of cancer patients or individuals who suffer from an immune defect.

Fabrication of Calcium Sulfate Coated Selenium Nanoparticles and Corresponding In-Vitro Cytotoxicity Effects Against 4T1 Breast Cancer Cell Line.

BACKGROUND: The inhibitory effect of selenium nanoparticles (SeNPs) on cancer cells has been reported in many studies. In this study, the purpose was to compare the in vitro effects of SeNPs and calcium sulfate coated selenium nanoparticles (CaSO4@SeNPs) on breast cancer cells. METHODS: CaSO4@SeNPs and SeNPs were chemically synthesized and characterized with Field Emission Scanning Electron Microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDX). By applying MTT assay, the cytotoxicity effect of both nanomaterials on the 4T1 cancer cells was investigated. RESULTS: While LD50 of SeNPs on 4T1 cancer cells was 80 µg, the LD50 of CaSO4@SeNPs was reported to be only 15 µg. The difference between the inhibition rates obtained for SeNPs and CaSO4@SeNPs was statistically significant (p=0.05). In addition, at higher concentrations (50 µg) of CaSO4@SeNPs, the cytotoxicity was 100% more than SeNPs alone. CONCLUSION: According to the result of the present work, it can be concluded that decoration of SeNPs with calcium sulfate leads to an increase in potency by decreasing the effective dose. This effect can be attributed to activation of intrinsic apoptosis signaling and/or pH regulatory properties of CaSO4@SeNPs. However, further studies are still needed to determine the exact corresponding mechanisms of this synergistic effect.

Biosynthesis and recovery of selenium nanoparticles and the effects on matrix metalloproteinase-2 expression.

Today, green synthesis of nanoparticles is attracting increasing attention. In the present study, the Bacillus sp. MSh-1 was isolated from the Caspian Sea (located in the northern part of Iran) and identified by various identification tests and 16S ribosomal DNA analysis. The reduction time course study of selenium ion (Se(4+)) reduction by using this test strain was performed in a liquid culture broth. Then, the intracellular NPs (nanoparticles) were released by the liquid nitrogen disruption method and thoroughly purified using an n-octyl alcohol water extraction system. Characterization of the separated NPs on features such as particle shape, size and purity was carried out with different devices. The energy dispersive X-ray and X-ray diffraction patterns showed that the purified NPs consisted of only selenium and are amorphous respectively. In addition, the transmission electron micrograph showed that the separated NPs were spherical and 80-220 nm in size. Furthermore, the cytotoxicity effect of these extracted biogenic selenium (Se) NPs on the fibrosarcoma cell line (HT-1080) proliferation and the inhibitory effect of the Se NPs on MMP-2 (matrix metalloproteinase-2) expression were studied using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and gelatin zymography. Biogenic Se NPs showed a moderately inhibitory effect on MMP-2 expression.

Green synthesis of gold nanoparticles by the marine microalga Tetraselmis suecica.

The application of green-synthesis principles is one of the most impressive research fields for the production of nanoparticles. Different kinds of biological systems have been used for this purpose. In the present study, AuNPs (gold nanoparticles) were prepared within a short time period using a fresh cell extract of the marine microalga Tetraselmis suecica as a reducing agent of HAuCl4 (chloroauric acid) solution. The UV-visible spectrum of the aqueous medium containing AuNPs indicated a peak at 530 nm, corresponding to the surface plasmon absorbance of AuNPs. The X-ray diffraction pattern also showed a Bragg reflection related to AuNPs. Fourier-transform infrared spectroscopy was performed for analysis of surface functional groups of AuNPs. Transmission electron microscopy and particle-size-distribution patterns determined by the laser-light-scattering method confirmed the formation of well-dispersed AuNPs. The most frequent size of particles was 79 nm.