Clinical decision support systems (CDSS) in assistance to COVID-19 diagnosis: A scoping review on types and evaluation methods.

Background and Aims: Due to the COVID-19 pandemic, a precise and reliable diagnosis of this disease is critical. The use of clinical decision support systems (CDSS) can help facilitate the diagnosis of COVID-19. This scoping review aimed to investigate the role of CDSS in diagnosing COVID-19. Methods: We searched four databases (Web of Science, PubMed, Scopus, and Embase) using three groups of keywords related to CDSS, COVID-19, and diagnosis. To collect data from studies, we utilized a data extraction form that consisted of eight fields. Three researchers selected relevant articles and extracted data using a data collection form. To resolve any disagreements, we consulted with a fourth researcher. Results: A search of the databases retrieved 2199 articles, of which 68 were included in this review after removing duplicates and irrelevant articles. The studies used nonknowledge-based CDSS (n = 52) and knowledge-based CDSS (n = 16). Convolutional Neural Networks (CNN) (n = 33) and Support Vector Machine (SVM) (n = 8) were employed to design the CDSS in most of the studies. Accuracy (n = 43) and sensitivity (n = 35) were the most common metrics for evaluating CDSS. Conclusion: CDSS for COVID-19 diagnosis have been developed mainly through machine learning (ML) methods. The greater use of these techniques can be due to their availability of public data sets about chest imaging. Although these studies indicate high accuracy for CDSS based on ML, their novelty and data set biases raise questions about replacing these systems as clinician assistants in decision-making. Further studies are needed to improve and compare the robustness and reliability of nonknowledge-based and knowledge-based CDSS in COVID-19 diagnosis.

Chitosan-sialic acid nanoparticles of selenium: Statistical optimization of production, characterization, and assessment of cytotoxic effects against two human glioblastoma cell lines.

According to the favorable antitumor properties of selenium, this study aimed to design a novel form of selenium nanoparticles (Se NPs) functionalized with chitosan (Cs) and sialic acid to assess their antitumor effects on the human glioblastoma cell lines (T98 and A172). Se NPs were synthesized in the presence of chitosan and ascorbic acid (Vc) and the synthesis conditions were optimized using response surface methodology. Se NPs@Cs were obtained with a monoclinic structure with an average diameter of 23 nm under the optimum conditions (reaction time = 30 min, chitosan concentration = 1 % w/v, Vc/Se molar ratio = 5). To modify Se NP@Cs for glioblastoma treatment, sialic acid was used to cover the surface of the NPs. Sialic acid was successfully attached to the surface of Se NPs@Cs, and Se NPs@Cs-sialic acid were formed in the size range of 15-28 nm. Se NPs@Cs-sialic acid were stable for approximately 60 days at 4 ℃. The as-synthesized NPs exerted inhibitory effects on T98 greater than 3 T3 > A172 cells in a dose- and time-dependent manner. Additionally, sialic acid ameliorated the blood biocompatibility of Se NPs@Cs. Taken together, sialic acid improved both the stability and biological activity of Se NPs@Cs.

Hydroxyapatite/Glycyrrhizin/Lithium-Based Metal-Organic Framework (HA/GL/Li-MOF) Nanocomposite as Support for Immobilization of Thermomyces lanuginosus Lipase.

The hydroxyapatite/glycyrrhizin/lithium-based metal-organic framework (HA/GL/Li-MOF) nanocomposites were synthesized via the hydrothermal method in the presence of lecithin and glycyrrhizin. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) were applied for characterization of the fabricated nanocomposites. The HA/GL/Li-MOF and Li-MOF nanocomposites were employed as support for immobilization of Thermomyces lanuginosus lipase (TLL). The Plackett-Burman and Box-Behnken designs were used for screening and optimizing of variables affecting the immobilization conditions, respectively. The optimum specific activity of immobilized TLL on HA/GL/Li-MOF and Li-MOF nanocomposites (41.8 ± 1.2 U/mg and 39.4 ± 3.1 U/mg, respectively) was predictably determined at support concentration of 0.5 mg/mL, glutaraldehyde concentration of 5 mM, and enzyme activity of 20 U/mg, while the specific activities of TLL@ HA/GL/Li-MOF and TLL@Li-MOF were experimentally found to be 39.5 ± 3.7 U/mg and 38.5 ± 2.3 U/mg, respectively. The stability results showed that the TLL@ HA/GL/Li-MOF has suitable stability against pH and thermal denaturation. However, the immobilized TLL on Li-MOF represented lower stability compared with that of the HA/GL/Li-MOF. The immobilized TLL on HA/GL/Li-MOF maintained near 70% of its original activity after 15 days' storage and during 5 runs of application. In addition, TLL@HA/GL/Li-MOF exhibited higher enzyme-substrate affinity (Km, 10.1 mM) compared to that of TLL@Li-MOF (Km, 23.4 mM). Therefore, these findings demonstrated the potential use of HA/GL/Li-MOF nanocomposites for enzyme immobilization.

Rapid microwave-assisted biosynthesis of platinum nanoparticles and evaluation of their antioxidant properties and cytotoxic effects against MCF-7 and A549 cell lines.

In this study, platinum nanoparticles (Pt NPs) were synthesized by a green method using an aqueous extract of Eucalyptus camaldulensis with assistance of microwave irradiation (850 W) and their physicochemical characteristics were studied by UV-visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. Antioxidant activities, hemocompatibility, and cytotoxic effects of the prepared Pt NPs were then evaluated. The attained results showed that the newly formed Pt NPs possess a size range between 7.4 and 11.2 nm. These spherical-shaped NPs were slightly aggregated and held various functional groups on their surface. The antioxidant activity of Pt nanostructures was comparable to that of butylated hydroxyl anisole at concentrations higher than 320 µg/mL. At the same concentration of 640 µg/mL, the scavenging activities were 3.36 ± 0.9% (hexachloroplatinic acid) and 52.13 ± 0.43% (Pt NPs). The results of hemolytic assay revealed satisfactory hemocompatibility of the Pt NPs even at the concentration as high as 4 mg/mL (hemolysis percent equal to 3.5 ± 1.3%). The cytotoxicity studies revealed that MCF-7, A549, and 3T3 cell lines treated with hexachloroplatinic acid and cisplatin for 24 h and 48 h showed a higher percentage of cell death compared with the Pt NPs. After 24 h, for A549, 3T3, and MCF-7 cells exposed to Pt NPs, the cell viability was measured to be 80 ± 3.2%, 96 ± 1%, and 89 ± 2.6%, respectively, at concentration of 640 µg/mL. Further investigations are required to elucidate the mechanisms behind the biological activities of as-synthesized Pt NPs.

Polycaprolactone/gelatin electrospun nanofibres containing biologically produced tellurium nanoparticles as a potential wound dressing scaffold: Physicochemical, mechanical, and biological characterisation.

The biologically synthesised tellurium nanoparticles (Te NPs) were applied in the fabrication of Te NP-embedded polycaprolactone/gelatin (PCL/GEL) electrospun nanofibres and their antioxidant and in vivo wound healing properties were determined. The as-synthesised nanofibres were characterised using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and elemental mapping, thermogravimetric analysis (TGA), and Fourier-transform infrared (FTIR) spectroscopy. The mechanical properties and surface hydrophobicity of scaffolds were investigated using tensile analysis and contact angle tests, respectively. The biocompatibility of the produced scaffolds on mouse embryonic fibroblast cells (3T3) was evaluated using MTT assay. The highest wound healing activity (score 15/19) was achieved for scaffolds containing Te NPs. The wounds treated with PCL/GEL/Te NPs had inflammation state equal to the positive control. Also, the mentioned scaffold represented positive effects on collagen formation and collagen fibre's horizontalisation in a dose-dependent manner. The antioxidative potency of Te NP-containing scaffolds was demonstrated with lower levels of malondialdehyde (MDA) and catalase (∼3 times) and a higher level of glutathione (GSH) (∼2 times) in PCL/GEL/Te NP-treated samples than the negative control. The obtained results strongly demonstrated the healing activity of the produced nanofibres, and it can be inferred that scaffolds containing Te NPs are suitable for wound dressing.

Optimization of immobilization of Pseudomonas cepacia lipase on multiwalled carbon nanotubes functionalized with glycyrrhizin and Tween 80.

In the present study, multiwalled carbon nanotubes (MWCNTs) were functionalized with glycyrrhizin and Tween 80 and applied for immobilization of Pseudomonas cepacia lipase (PcL). Characterization of f-MWCNTs was performed through Fourier-transform infrared spectroscopy, thermal gravimetric, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis. The optimum specific activity of immobilized PcL (studied by Plackett-Burman statistical design) occurred at 0.3 mg/mL of f-MWCNTs, 25 mM of phosphate buffer (pH 6.0), 15 min sonication time, 8 U/mL of enzyme concentration, and 24 h immobilization time at 4 °C in the absence of glutaraldehyde. In these conditions, the specific activity was 16.57 ± 0.71 U/mg, which was very close to the predicted amount (16.62 ± 0.64 U/mg). The results of thermal and pH stability showed that the stability of immobilized PcL was higher than that of the free PcL. The activity of immobilized PcL on f-MWCNTs held 93% after being incubated for 60 min at 70 °C. Moreover, the immobilized PcL on f-MWCNTs retained about 65% of its initial activity after 30 days of storage at 25 °C. In addition, about 50% of initial activity of immobilized PcL retained after 10 cycles of uses. Therefore, f-MWCNTs could be introduced as suitable support for enzymes immobilization.

Lipase@zeolitic imidazolate framework ZIF-90: A highly stable and recyclable biocatalyst for the synthesis of fruity banana flavour.

A zeolitic imidazolate framework (ZIF-90) has been synthesized through solvothermal method. The structure was characterized by means of FT-IR spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS). The synthesized ZIF-90 was applied as a support for immobilization of porcine pancreatic lipase (PPL). The immobilized enzyme (PPL@ZIF-90) exhibited immobilization yield and efficiency of 66 ± 1.8% and 89 ± 1.4%, respectively. The pH and thermal stability of PPL was improved after immobilization and the initial activity was retained at about 57% after 20 days of storage at 4 °C for PPL@ZIF-90. Moreover, about 57% of the original activity was remained following 10 cycles of application. In Michaelis-Menten kinetic studies, Km value for PPL@ZIF-90 was lower, while, the Vmax was higher than free PPL. Moreover, optimized conditions to produce fruity banana flavour upon esterification of butyric acid were investigated. The optimum esterification yield was 73.79 ± 1.31% in the presence of 245 mg PPL@ZIF-90, alcohol/acid ratio of 2.78 and 39 h reaction time. PPL@ZIF-90 showed 39% relative esterification yield after six cycles of reuse. The results suggested that PPL@ZIF-90 can be used as a potential effective biocatalyst for synthesis of isoamyl butyrate.

Optimization of immobilization conditions of Bacillus atrophaeus FSHM2 lipase on maleic copolymer coated amine-modified graphene oxide nanosheets and its application for valeric acid esterification.

The thermoalkalophilic lipase from Bacillus atrophaeus (BaL) was immobilized onto amine-functionalized graphene oxide nanosheets coated with the poly (maleic anhydride-alt-1-octadecene) copolymer (GO-NH2-PMAO) and activated with glutaraldehyde as spacer arm through interfacial activation and subsequent multipoint covalent attachment. Experimental design method was applied for optimization of immobilization conditions including GO-NH2-PMAO concentration, buffer concentration, pH, sonication time, enzyme concentration, glutaraldehyde concentration, time, and temperature. The optimum specific activity of the immobilized BaL (105.95 ± 2.37 U/mg) reached at 5 mg/mL for GO-NH2-PMAO, 25 mM of buffer, pH 6.0, 60 min sonication time, 100 mM glutaraldehyde, 60 U/mL of enzyme, and 4 h of immobilization time at 25 °C, which was very close to the predicted amount (106.08 ± 1.42 U/mg). Maximum immobilization yield (81.35%) and efficiency (277.63%) were determined in optimal immobilization conditions. The obtained results clearly indicated that the immobilized BaL exhibited better stability at extreme temperature and pH than the free BaL. At temperature of 90 °C and pH 11, more than 90% of the initial activity of the immobilized BaL was retained. Furthermore, the immobilized BaL retained about 90% of its initial activity after 10 days of storage and 6 cycles of application. The esterification studies showed that maximum bioconversion of valeric acid to pentyl valerate using the free BaL (34.5%) and the immobilized BaL (96.3%) occurred in the xylene medium after 48 h of incubation at 60 °C. Therefore, the BaL immobilized on GO-NH2-PMAO was introduced as an effective biocatalyst to synthesize green apple flavour ester.

Immobilization of Thermoalkalophilic Lipase from Bacillus atrophaeus FSHM2 on Amine-Modified Graphene Oxide Nanostructures: Statistical Optimization and Its Application for Pentyl Valerate Synthesis.

Synthesis of (3-aminopropyl) triethoxysilane (APTES)-functionalized graphene oxide (GO) nanosheets, statistical optimization of conditions for immobilization of Bacillus atrophaeus lipase (BaL) on as-synthesized support, and application of the immobilized BaL for esterification of valeric acid were carried out in this investigation. The optimum specific activity of the immobilized BaL (81.60 ± 0.28 U mg-1) was achieved at 3 mg mL-1 of GO-NH2, 50 mM of phosphate buffer, pH 7.0, 60 min sonication time, 100 mM glutaraldehyde, 25 U mL-1 of enzyme, and 8 h immobilization time at 4 °C. The immobilized BaL retained about 90% of its initial activity after 10 days of storage. Moreover, about 70% of the initial activity of the immobilized BaL was retained after 10 cycles of application. The results of esterification studies exhibited that maximum pentyl valerate synthesis using the free BaL (34.5%) and the immobilized BaL (92.7%) occurred in the organic solvent medium (xylene) after 48 h of incubation at 60 °C.

Antimicrobial, anti-biofilm, and anti-proliferative activities of lipopeptide biosurfactant produced by Acinetobacter junii B6.

Lipopeptide biosurfactants (LPBs) are amphiphilic compounds produced by microorganisms exhibiting various biological activities. The main aim of the present study was to assess the in vitro antimicrobial, anti-biofilm, and cytotoxic effects of LPB produced by Acinetobacter junii (AjL). We determined AjL minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria as well as two fungal strains. Also, the anti-biofilm activity of AjL against the biofilm produced by clinically isolated bacterial strains was investigated. The AjL non-selectively showed activity against both Gram-positive and Gram-negative bacterial strains. The obtained results of the present study exhibited that the AjL in concentrations nearly below critical micelle concentration (CMC) has an effective antibacterial activity. It was found that the MIC values of AjL were lower than standard antifungal and it exhibited nearly 100% inhibition against Candida utilis. The attained results of the biofilm formation revealed that AjL disrupted the biofilm of Proteus mirabilis, Staphylococcus aureus, and Pseudomonas aeruginosa at 1250 µg/ml and 2500 µg/ml concentrations. The attained results of cytotoxic effect (determined by WST-1 assay) of the AjL revealed IC50 of 7.8 ±â€¯0.4 mg/ml, 2.4 ±â€¯0.5 mg/ml, and 5.7 ±â€¯0.1 mg/ml, against U87, KB, and HUVEC cell lines, respectively. The results indicated that AjL has a potential application in the relatively new field of biomedicine.

Rapid and Facile Microwave-Assisted Synthesis of Palladium Nanoparticles and Evaluation of Their Antioxidant Properties and Cytotoxic Effects Against Fibroblast-Like (HSkMC) and Human Lung Carcinoma (A549) Cell Lines.

We report here a simple microwave irradiation method (850 W, 3 min) for the synthesis of palladium nanoparticles (Pd NPs) using ascorbic acid (as reducing agent) and sodium alginate (as stabilizer agent). The synthesized nanoparticles were characterized using transmission electron microscopy (TEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy (XRD), UV-Visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) techniques. Antioxidant properties and cytotoxic effects of as-synthesized Pd NPs and Pd (II) acetate were also assessed. UV-Vis study showed the formation of Pd NPs with maximum absorption at 345 nm. From TEM analysis, it was observed that the Pd NPs had spherical shape with particle size distribution of 13-33 nm. Based on DPPH radical scavenging activity and reducing power assay, the antioxidant activities of Pd NPs were significantly higher than the Pd (II) acetate (p < 0.05). At the same concentration of 640 µg/mL, the scavenging activities were 32.9 ± 3.2% (Pd (II) acetate) and 27.2 ± 2.1% (Pd NPs). For A549 cells treated 48 h with Pd NPs, Pd (II) acetate, and cisplatin, the measured concentration necessary causing 50% cell death (IC50) was 7.2 ± 1.7 µg/mL, 32.1 ± 2.1 µg/mL, and 206.2 ± 3.5 µg/mL, respectively. On HSkMC cells, the IC50 of the Pd NPs (320 µg/mL) was higher compared to Pd (II) acetate (228.7 ± 3.6 µg/mL), which confirmed lower cytotoxicity of the Pd NPs.

Preliminary survey of extended-spectrum ß-lactamases (ESBLs) in nosocomial uropathogen Klebsiella pneumoniae in north-central Iran.

Infections caused by extended-spectrum ß-lactamases (ESBLs) producing bacteria, including Klebsiella pneumoniae have increasingly subjected to therapeutic limitations and patients with these infections are at high risk for treatment failure, long hospital stays, high health care costs, and high mortality. The aim of this study was to screen the prevalence of the bla TEM,bla CTX-M and bla SHV ESBL genes in K. pneumoniae strains isolated from nosocomial urinary tract infections (UTIs). During the March 2016 to December 2017, one hundred isolates of K. pneumoniae were collected from urine specimens of patients suffering from nosocomial UTI referred to Khatam Al-Anbia hospital in Shahrud, north-central Iran. All isolates were identified by standard bacteriological tests. The pattern of antibiotic susceptibility was determined according to the CLSI guidelines. The presence of the ESBLs was investigated using the double-disc synergy test (DDST). Polymerase chain reaction technique was used to detect the bla TEM, bla CTX-M and bla SHV genes in DDST positive isolates. Most isolates showed remarkable resistance to tested antibiotics with highest rate against nitrofurantoin (75%) and trimethoprim/sulfamethoxazole (65%). The imipenem was the most effective antibiotic against K. pneumoniae isolates. ESBL phenotype was detected in 50 (50%) of isolates. The prevalence of bla TEM, bla CTX-M and bla SHV genes among 50 ESBLs-positive isolates was 25 (50%), 15 (30%) and 35 (70%) respectively. The bla TEM and bla SHV genes were seen in 25 isolates (50%) simultaneously. The findings of this study indicated the 50% frequency rate of ESBL-producing K. pneumoniae in our geographic region. Since the treatment of infections caused by this bacterium is associated with many limitations, this high prevalence is a warning sign to adopt new control policies to prevent further spread of this microorganism.

Hydrogels For Peptide Hormones Delivery: Therapeutic And Tissue Engineering Applications.

Peptides are the most abundant biological compounds in the cells that act as enzymes, hormones, structural element, and antibodies. Mostly, peptides have problems to move across the cells because of their size and poor cellular penetration. Therefore, a carrier that could transfer peptides into cells is ideal and would be effective for disease treatment. Until now, plenty of polymers, e.g., polysaccharides, polypeptides, and lipids were used in drug delivery. Hydrogels made from polysaccharides showed significant development in targeted delivery of peptide hormones because of their natural characteristics such as networks, pore sizes, sustainability, and response to external stimuli. The main aim of the present review was therefore, to gather the important usages of the hydrogels as a carrier in peptide hormone delivery and their application in tissue engineering and regenerative medicine.

Ondansetron enhanced diclofenac-induced nephrotoxicity in mice.

This study was performed to investigate the effect of ondansetron, a serotonin receptor (5-HT3) antagonist, in the alleviation of diclofenac-induced kidney injuries. NMRI mice were randomly divided into six groups and treated with (A) untreated control group, (B) diclofenac (100 mg/kg), (C) ondansetron (1 mg/kg), (D to F) ondansetron (0.1, 0.5, and 1 mg/kg, respectively) and diclofenac (100 mg/kg) for last 3 days of experiment. The oxidative stress tests strongly demonstrated the negative synergistic effects of diclofenac and ondansetron, regarding the observation of dose-dependent enhancement of malondialdehyde concentration, and reduction of glutathione content, and superoxide dismutase and catalase activity. Histopathological analyses revealed dose-dependent tubular epithelial cells degeneration, outstanding mononuclear cells infiltration, clear necrosis at the papillary region of kidney, dilation, and vascular hyperemia in mice kidney tissues treated with ondansetron and diclofenac. Conclusively, these findings suggested the possible ondansetron-diclofenac interaction through the induction of oxidative stress.

Statistical optimization of cultural medium composition of thermoalkalophilic lipase produced by a chemically induced mutant strain of Bacillus atrophaeus FSHM2.

Extremophilic microbial derived lipases have been widely applied in different biotechnological processes due to their resistance to harsh conditions such as high salt concentration, elevated temperature, and extreme acidic or alkaline pH. The present study was designed to overproduce the halophilic, thermoalkalophilic lipase of Bacillus atrophaeus FSHM2 through chemically induced random mutagenesis and optimization of cultural medium components assisted by statistical experimental design. At first, improvement of lipase production ability of B. atrophaeus FSHM2 was performed through exposure of the wild bacterial strain to ethidium bromide for 5-90 min to obtain a suitable mutant of lipase producer (designated as EB-5, 4301.1 U/l). Afterwards, Plackett-Burman experimental design augmented to D-optimal design was employed to optimize medium components (olive oil, maltose, glucose, sucrose, tryptone, urea, (NH4)2SO4, NaCl, CaCl2, and ZnSO4) for lipase production by the EB-5 mutant. A maximum lipase production of 14,824.3 U/l was predicted in the optimum medium containing 5% of olive oil, 0.5% of glucose, 0.5% of sucrose, 2% of maltose, 2.5 g/l of yeast extract, 1.75 g/l of urea, 1.75 g/l of (NH4)2SO4, 2.5 g/l of tryptone, 2 g/l of NaCl, 1 g/l of CaCl2, and 1 g/l of ZnSO4. A mean value of 14,773 ± 576.9 U/l of lipase was acquired from real experiments.

Toxicity of microwave-assisted biosynthesized zinc nanoparticles in mice: a preliminary study.

This study was designed to describe the oral acute and subacute toxicities and underlying toxicological mechanisms of biogenic Zn NPs in mice. The Zn NPs were prepared by a green microwave-assisted synthesis method in the presence of Lavandula vera leaf extract. Determination of median lethal dose (LD50) of Zn NPs and the subacute toxicity after 14 days of exposure was performed as a measurement of substance toxicity through general toxicological, hematological, serum, and histopathological investigations. The western blotting was used to determine the cleaved-caspase-3 expression in the sampled tissues. Flame atomic absorption spectrophotometer (AAS) was applied to estimate the Zn levels in tissues. The SEM analyses revealed that the biogenic Zn NPs were spherical-shaped with the size range of 30-80 nm. The LD50 value above 5 g/kg indicated that biogenic Zn NPs could be classified as non-toxic chemicals. In subacute toxicity, no significant differences were found in the body weight as well as hematological and oxidative stress (OS) biomarkers after exposure to Zn NPs at the dose of 1 g/kg in comparison to the control. The AAS results indicated that Zn NPs were mainly distributed in the testis, liver, and brain. The findings of histology images of Zn NPs at the dose of 1 g/kg were similar to those of the control. Furthermore, no significant differences were observed in cleaved-caspase-3 expression after exposure to Zn NPs at the dose of 5 g/kg. The results demonstrated that changes in the OS were not related to caspase pathway and the no-observed-adverse-effect level (NOAEL) dose of biogenic Zn NPs in 14-days subacute toxicity study was lower than 1 g/kg.

Overproduction of thermoalkalophilic lipase secreted by Bacillus atrophaeus FSHM2 using UV-induced mutagenesis and statistical optimization of medium components.

Microbial enzymes of extremophilic origin serve as a vital source of stable industrial enzymes. The present study focused on overproduction of a thermoalkalophilic lipase produced by Bacillus atrophaeus FSHM2 through UV-induced random mutagenesis (5-45 min exposure to UV light) and factorial experimental design augmented to response surface methodology. Firstly, a UV-induced mutant (designated as UV-45) was developed after the exposure of wild strain to UV irradiation for 45 min which was able to secrete 3484.8 U/L lipase. Afterward, Plackett-Burman experimental approach augmented to central composite design was employed to optimize medium components (olive oil, maltose, glucose, sucrose, yeast extract, tryptone, urea, (NH4)2SO4, NaCl, CaCl2, and ZnSO4) for lipase production by the UV-45 mutant strain. The maximum lipase production of 5505.3 U/L were predicted in medium containing 5% of olive oil, 0.69% of glucose, 0.69% of sucrose, 2.5% of maltose, yeast extract (0.7 g/L), urea (0.44 g/L), (NH4)2SO4 (2.44 g/L), tryptone (1.19 g/L), NaCl (1.61 g/L), CaCl2 (3.81 g/L), and ZnSO4 (1.42 g/L). A mean value of 5161.3 ± 83.3 U/L of lipolytic activity was acquired from real experiments. To sum up, the lipolytic activity of wild type strain (1720.4 U/L) increased by 3-fold after UV-induced mutagenesis and medium components optimization (5161.3 U/L).

Statistical optimization of kojic acid production by a UV-induced mutant strain of Aspergillus terreus

ABSTRACT The ability of four Aspergillus strains for biosynthesis of kojic acid was evaluated among which Aspergillus terreus represented the highest level (2.21 g/L) of kojic acid production. Improvement kojic acid production ability of A. terreus by random mutagenesis using different exposure time to ultraviolet light (5-40 min) was then performed to obtain a suitable mutant of kojic acid production (designated as C5-10, 7.63 g/L). Thereafter, design of experiment protocol was employed to find medium components (glucose, yeast extract, KH2PO4 (NH4)2SO4, and pH) influences on kojic acid production by the C5-10 mutant. A 25-1 fractional factorial design augmented to central composite design showed that glucose, yeast extract, and KH2PO4 were the most considerable factors within the tested levels (p < 0.05). The optimum medium composition for the kojic acid production by the C5-10 mutant was found to be glucose, 98.4 g/L; yeast extract, 1.0 g/L; and KH2PO4, 10.3 mM which was theoretically able to produce 120.2 g/L of kojic acid based on the obtained response surface model for medium optimization. Using these medium compositions an experimental maximum Kojic acid production (109.0 ± 10 g/L) was acquired which verified the efficiency of the applied method.

Cytotoxicity of biologically synthesised bismuth nanoparticles against HT-29 cell line.

This study was purposed to examine the cytotoxicity and functions of biologically synthesised bismuth nanoparticles (Bi NPs) produced by Delftia sp. SFG on human colon adenocarcinoma cell line of HT-29. The structural properties of Bi NPs were investigated using transmission electron microscopy, energy dispersive X-ray, and X-ray diffraction techniques. The cytotoxic effects of Bi NPs were analysed using flow cytometry cell apoptosis while western blot analyses were applied to analyse the cleaved caspase-3 expression. Oxidative stress (OS) damage was determined using the measurement of the glutathione (GSH) and malondialdehyde (MDA) levels and antioxidant activity of superoxide dismutase (SOD) and catalase (CAT) levels. The half maximal inhibitory concentration (IC50) value of Bi NPs was measured to be 28.7 ± 1.4 µg/ml on HT-29 cell line. The viability of HT-29 represented a concentration-dependent pattern (5-80 µg/ml). The mode of Bi NPs induced apoptosis was found to be mainly related to late apoptosis or necrosis at IC50 concentration, without the effect on caspase-3 activities. Furthermore, Bi NPs reduced the GSH and increased the MDA levels and decreased the SOD and CAT activities. Taken together, biogenic Bi NPs induced cytotoxicity on HT-29 cell line through the activation of late apoptosis independent of caspase pathway and may enhance the OS biomarkers.

Statistical optimization of kojic acid production by a UV-induced mutant strain of Aspergillus terreus.

The ability of four Aspergillus strains for biosynthesis of kojic acid was evaluated among which Aspergillus terreus represented the highest level (2.21g/L) of kojic acid production. Improvement kojic acid production ability of A. terreus by random mutagenesis using different exposure time to ultraviolet light (5-40min) was then performed to obtain a suitable mutant of kojic acid production (designated as C5-10, 7.63g/L). Thereafter, design of experiment protocol was employed to find medium components (glucose, yeast extract, KH2PO4 (NH4)2SO4, and pH) influences on kojic acid production by the C5-10 mutant. A 25-1 fractional factorial design augmented to central composite design showed that glucose, yeast extract, and KH2PO4 were the most considerable factors within the tested levels (p<0.05). The optimum medium composition for the kojic acid production by the C5-10 mutant was found to be glucose, 98.4g/L; yeast extract, 1.0g/L; and KH2PO4, 10.3mM which was theoretically able to produce 120.2g/L of kojic acid based on the obtained response surface model for medium optimization. Using these medium compositions an experimental maximum Kojic acid production (109.0±10g/L) was acquired which verified the efficiency of the applied method.