Brain waves and landscape settings: emotional responses to attractiveness.

Neuro-architecture is a specific branch of architecture that studies how the physical environment can change our mental processes and influence our behaviors. One of the main purposes of this field is to use changes in brain activities as a measure to quantify attractiveness of the landscapes. In this study, we investigated how changes in elements of attractiveness influence ones' emotional perception and present the related pattern of changes in brain activities. Therefore, we implied five elements of attractiveness including mystery, visual openness, landscape or greenness, walkability, and social interaction using the Delphi method. Then, we made changes in each element separately to make the landscape more attractive and assessed their effects on a group of young adults. We used the self-assessment manikin questionnaire to measure the participants' emotional perception while the participants' brain activities were recorded using a 32-channel EEG while exposed to the landscape images. The results showed that changes in attractive elements of the landscape could significantly improve ones' emotional perception of the landscape. In addition, these changes are perceived by changing the oscillatory pattern of brain activities. We hope these findings could shed a light to use of neural markers in measurement of place attractiveness.

Neuropharmacokinetic evaluation of lactoferrin-treated indinavir-loaded nanoemulsions: remarkable brain delivery enhancement.

OBJECTIVE: Indinavir (IDV), an antiretroviral protease inhibitor used in treatment of HIV infection, has limited entry into brain due to efflux by the P-glycoprotein presented in blood-brain barrier. The aim of present study was to develop lactoferrin-treated nanoemulsion containing indinavir (Lf-IDV-NEs) for delivery to brain. METHODS: Indinavir-loaded nanoemulsions (IDV-NEs) were prepared by high-speed homogenization method, and then lactoferrin was coupled to IDV-NEs by water soluble EDC method. RESULTS: The hydrodynamic diameters, polydispersity index, and zeta potential of IDV-NEs were 112 ± 3.5 nm, 0.20 ± 0.02, and -33.2 ± 2.6 mV, respectively. From in vivo studies in animal model of rats, the AUC0-4 h of brain concentration-time profile of IDV-NEs and Lf-IDV-NEs were 1.6 and 4.1 times higher than free drug, respectively. The brain uptake clearance of IDV-NEs and Lf-IDV-NEs were, interestingly, 393- and 420-times higher than the free drug. CONCLUSIONS: It can be concluded that applying both lactoferrin-treated and non-treated nanoemulsions clearly leads to significant brain penetration enhancement of indinavir, an effect which is more pronounced in the case of Lf-IDV-NEs with the higher drug residence time in brain.

Expression of Bcl-2 and Bax genes in peripheral blood lymphocytes of depressed and nondepressed individuals.

BACKGROUND: Involvement of the immune system is one of the issues raised in the pathophysiology of depression. BCL2 and BAX genes are related to immune system regulation. We investigated the BCL2 and BAX expression as a probable mechanism of immune system involvement in depression. MATERIALS AND METHODS: This case-control study was conducted on 28 patients with major depression (case) and 28 nondepressed individuals (control) within the age range of 18-55 years in the Isfahan University of Medical Sciences. Clinical interviews, based on the Diagnostic and Statistical Manual of Mental Disorders, were conducted to detect depression, and Beck's Depression Inventory was used to measure the severity of depression in the individuals. In addition, a real-time polymerase chain reaction was employed to compare the level of Bax and Bcl-2 gene expression in peripheral blood lymphocytes. The multivariate covariance analysis was used to explore the correlation between BCL2 and BAX gene expression and to control the effect of duration and severity of depression. RESULTS: The results showed that none of the variables including group membership, the duration of depression, and the severity of depression were not significantly correlated with the expression of BCL2 and BAX genes. Furthermore, there was no statistically significant relationship between the Bax and Bcl-2 genes expression in case and control groups (P > 0.05). CONCLUSION: Depression may have no impact on Bax and Bcl-2 gene expression in patients with major depression. Studies with larger sample size are recommended.

Evaluation of Lymphocyte Transformation Test Results in Patients with Delayed Hypersensitivity Reactions following the Use of Anticonvulsant Drugs.

BACKGROUND/AIM: Administration of the anticonvulsant drugs phenobarbital, phenytoin, carbamazepine and lamotrigine can be associated with severe hypersensitivity reactions. The lymphocyte transformation test (LTT) is a method to determine which drug has caused the hypersensitivity reaction. This study was done to evaluate the results of LTT in patients with delayed hypersensitivity reactions following the administration of anticonvulsants. METHODS: Twenty-four patients with hypersensitivity reactions, e.g. drug-induced hypersensitivity syndrome/drug rash and eosinophilia with systemic symptoms (DIHS/DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN), following the administration of anticonvulsant drugs, and 24 patients who had used anticonvulsant drugs but did not have hypersensitivity reactions (the control group) were included in this study. Peripheral blood mononuclear cells were isolated. The cells were stimulated with the drugs, phytohemagglutinin as a mitogen and Candida as an antigen (positive controls). Lymphocyte proliferation was measured using the BrdU proliferation assay kit (Roche, Germany). The stimulation index was calculated as the mean ratio of the OD of stimulated cells divided by the OD of unstimulated cells. The results in the case and control groups were compared. RESULTS: Of 24 patients in the test group, 14 (58.3%) had positive LTT results and 10 (41.7%) had negative results. Among patients in the control group, 1 (4.2%) had a positive LTT result and 23 (95.8%) had negative results. Among the patients who had received carbamazepine and phenytoin, there was a significant difference between the results of LTT in the case and control groups (p = 0.002 and p = 0.028, respectively). Although patients receiving lamotrigine and phenobarbital had more positive LTT results in the case group than in the control group, these differences were not statistically significant. The sensitivity, specificity, positive predictive value and negative predictive value of LTT were 58.4, 95.8, 93.3 and 69.9%, respectively. CONCLUSIONS: Considering the significant difference in LTT results between the case and control groups in patients receiving carbamazepine and phenytoin, and not observing such a difference in patients receiving phenobarbital and lamotrigine, LTT results are more valuable for the diagnosis of hypersensitivity reactions following the administration of carbamazepine and phenytoin. The LTT has good specificity but low sensitivity for the diagnosis of drug hypersensitivity reactions.

Purification and characterization of a thermo- and organic solvent-tolerant alkaline protease from Bacillus sp. JER02.

Bacillus sp. JER02 is a bacterial strain that can be grown in a medium containing organic solvents and produce a protease enzyme. JER02 protease was purified with a yield of 31.9% of total protein and 328.83-fold purification. Km and Vmax of this protease were established as 0.826 µM and 7.18 µmol/min, respectively. JER02 protease stability was stimulated about 80% by cyclohexane. It exhibited optimum temperature activity at 70°C. Furthermore, this enzyme was active in a wide range of pH (4-12) and showed maximum activity at pH 9.0. The nonionic detergents Tween-20 and Triton X-100 improved the protease activity by 30 and 20%, respectively. In addition, this enzyme was shown to be very stable in the presence of strong anionic surfactants and oxidizing agents, since it retained 77%, 93%, and 98% of its initial activity, after 1 hr of incubation at room temperature with sodium dodecyl sulfate (SDS), sodium perborate (1%, v/v) and H2O2 (1%, v/v), respectively. Overall, the unique properties of the Bacillus sp. JER02 protease suggested that this thermo- and detergent-stable, solvent-tolerant protease has great potential for industrial applications.

Strategies for optimizing DNA hybridization on surfaces.

Specific and predictable hybridization of the polynucleotide sequences to their complementary counterparts plays a fundamental role in the rational design of new nucleic acid nanodevices. Generally, nucleic acid hybridization can be performed using two major strategies, namely hybridization of DNA or RNA targets to surface-tethered oligonucleotide probes (solid-phase hybridization) and hybridization of the target nucleic acids to randomly distributed probes in solution (solution-phase hybridization). Investigations into thermodynamic and kinetic parameters of these two strategies showed that hybridization on surfaces is less favorable than that of the same sequence in solution. Indeed, the efficiency of DNA hybridization on surfaces suffers from three constraints: (1) electrostatic repulsion between DNA strands on the surface, (2) steric hindrance between tethered DNA probes, and (3) nonspecific adsorption of the attached oligonucleotides to the solid surface. During recent years, several strategies have been developed to overcome the problems associated with DNA hybridization on surfaces. Optimizing the probe surface density, application of a linker between the solid surface and the DNA-recognizing sequence, optimizing the pH of DNA hybridization solutions, application of thiol reagents, and incorporation of a polyadenine block into the terminal end of the recognizing sequence are among the most important strategies for enhancing DNA hybridization on surfaces.

How readable are Australian paediatric oral health education materials?

BACKGROUND: The objective of this study was to analyse the readability of paediatric oral health education leaflets available in Australia. METHODS: Forty paediatric oral health education materials were analysed for general readability according to the following parameters: Thoroughness; Textual framework; Terminology; and Readability (Flesch-Kincaid grade level (FKGL), Gunning Fog index (Fog) and Simplified Measure of Gobbledygook (SMOG)). RESULTS: Leaflets produced by the industry were among the hardest to read with an average readability at the 8th grade (8.4 ± 0.1). The readability of leaflets produced by the commercial sector was at the 7th grade (7.1 ± 1.7) and the government at the 6th grade (6.3 ± 1.9). The FKGL consistently yielded readabilities 2 grades below the Fog and SMOG indexes. In the content analyses, 14 essential paediatric oral health topics were noted and Early Childhood Caries (ECC) was identified as the most commonly used jargon term. CONCLUSION: Paediatric oral health education materials are readily available, yet their quality and readability vary widely and may be difficult to read for disadvantaged populations in Australia. A redesign of these leaflets while taking literacy into consideration is suggested.

Novel pH-responsive alginate-stabilized curcumin-selenium-ZIF-8 nanocomposites for synergistic breast cancer therapy.

In this study, a novel selenium@zeolitic imidazolate framework core/shell nanocomposite stabilised with alginate was used to improve the anti-tumour activity of curcumin. The developed alginate-stabilised curcumin-loaded selenium@zeolitic imidazolate framework (Alg@Cur@Se@ZIF-8) had a mean diameter of 159.6 nm and polydispersity index < 0.25. The release of curcumin from the nanocarrier at pH 5.4 was 2.69 folds as high as at pH 7.4. The bare nanoparticles showed haemolytic activity of about 12.16% at a concentration of 500 µg/mL while covering their surface with alginate reduced this value to 5.2%. By investigating cell viability, it was found that Alg@Cur@Se@ZIF-8 caused more cell death than pure curcumin. Additionally, in vivo studies showed that Alg@Cur@Se@ZIF-8 dramatically reduced tumour growth compared to free curcumin in 4T1 tumour-bearing mice. More importantly, the histological study confirmed that the developed drug delivery system successfully inhibited lung and liver metastasis while causing negligible toxicity in vital organs. Overall, due to the excellent inhibitory activity on cancerous cell lines and tumour-bearing animals, Alg@Cur@Se@ZIF-8 can be considered promising for breast cancer therapy.

How do lipid-based drug delivery systems affect the pharmacokinetic and tissue distribution of amiodarone? A comparative study of liposomes, solid lipid nanoparticles, and nanoemulsions.

Objectives: Lipid-based drug delivery systems (DDS) can improve the pharmacokinetic (PK) parameters of some drugs. Especially those with a high volume of distribution (Vd) leading to off-target accumulation and toxicity. Amiodarone as an anti-arrhythmic agent induces hypothyroidism and liver disorders limiting its clinical indication. Materials and Methods: In the present study, amiodarone PK parameters and biodistribution after IV administration of four nano-formulations to rats were compared. The formulations were liposomes, solid lipid nanoparticles (SLN), PEGylated SLN (PEG-SLN), and nanoemulsions (NE). All formulations were optimized. Results: The nanoparticles were spherical with a diameter of 100-200 nm and sustained in vitro drug release in buffer pH 7.4. The best-fitted model for the plasma concentration-time profile was two-compartmental. In vivo studies indicated the most changes in PKs induced after liposome, SLN, and NE administration, respectively. The area under the curve (AUC) and maximum plasma concentration (Cmax) of liposomes, SLN, and NE were 22.5, 2.6, 2.46 times, and 916, 58, and 26 times higher than that of amiodarone solution, respectively (P-value<0.05). The heart-to-liver ratio of amiodarone was higher for nano-formulations compared to drug solution except for liposomes. Conclusion: Lipid-based particles can improve the PK parameters of amiodarone and its distribution in different tissues.

Anti-inflammation-based treatment of atherosclerosis using Gliclazide-loaded biomimetic nanoghosts.

In the study, a biomimetic platform for anti-inflammatory-based treatment of atherosclerotic plaque was developed. Gliclazide (GL) as an anti-inflammasome agent was encapsulated in PLGA nanoparticles (NP), which were coated by monocyte membrane using an extrusion procedure. The size and zeta potential of the nanoghost (NG) changed to 292 and - 10 nm from 189.5 to -34.1 in the core NP. In addition, the actual size of 62.5 nm with a coating layer of 5 nm was measured using TEM. The NG was also showed a sustained release profile with the drug loading content of about 4.7%. Beside to attenuated TNFα, decrease in gene expression levels of NLRP3, MyD88, NOS, IL-1ß, IL-18 and caspases 1/3/8/9 in LPS-primed monocytes exposed to NG strongly indicated remarkable inflammation control. After systemic toxicity evaluation and pharmacokinetic analysis of NP and NG, intravenous NG treatment of rabbits with experimentally induced atherosclerosis revealed remarkably less plaque lesions, foam cells, lipid-laden macrophages, and pathological issues in tunica media of aorta sections. Higher expression of CD163 than CD68 in aorta of NG-treated rabbits strongly reveals higher M2/M1 macrophage polarization. The bio/hemocompatible, biomimetic and anti-inflammatory NG can be considered as a potential platform for immunotherapy of particularly atherosclerosis in the field of personalized medicine.

Influence of Poloxamer 188 on Anti-Inflammatory and Analgesic Effects of Diclofenac-Loaded Nanoemulsion: Formulation, Optimization and in Vitro/in Vivo Evaluation.

In this study, a polymer-stabilized nanoemulsion (PNE) was developed to improve the inflammatory and analgesic activities of diclofenac (DA). DA-PNEs were prepared from sesame oil and poloxamer 188 (P188), polysorbate 80, and span 80 as emulsifiers and optimized by a systematic multi-objective optimization method. The developed DA-PNEs exhibited thermodynamical stability with low viscosity. The mean diameter, PDI, surface charge, and entrapment efficiency of DA-PNEs were 122.49±3.42 nm, 0.226±0.08, -47.3 ± 3.6 mV, and 93.57±3.4 %, respectively. The cumulative in vitro release profile of DA-PNEs was significantly higher than the neat drug in simulated gastrointestinal fluids. The anti-inflammatory activities of DA-PNEs were evaluated in the λ-carrageenan-induced paw edema model. To investigate the effect of P188 on analgesic and anti-inflammatory activities, a formulation without P188 was also prepared and named DA-NEs. Following oral administration, DA-PNEs showed a significantly higher (p<0.05) effect in reducing pain and inflammation symptoms as compared to free diclofenac and DA-NEs. Moreover, histopathological examination confirmed that DA-PNEs meaningfully reduced the extent of paw edema, comparable to that of DA. Taken together, the findings of the in vitro and in vivo studies suggest that diclofenac-loaded P188-stabilized nanoemulsion can be considered a potential drug delivery system for treating and controlling inflammatory disorders and alleviating pains.

Pharmacokinetics and repeated dose 28-day oral toxicity studies of acetaminophen nanosuspension.

Wide availability and easy accessibility of acetaminophen oral dosage forms increase the risk of intentional poisoning or unintentional organ toxicity, leading to a wide range of liver failure, nephrotoxicity, and neurotoxicity. In this study, an attempt was made to improve oral bioavailability and reduce the toxicity of acetaminophen using nanosuspension technology. The acetaminophen nanosuspensions (APAP-NSs) were prepared by a nano-precipitation method using polyvinyl alcohol and hydroxypropylmethylcellulose as stabilizers. The mean diameter of APAP-NSs was 124 ± 3.8 nm. The dissolution profile of APAP-NSs was significantly point-to-point higher than the coarse drug in simulated gastrointestinal fluids. The in vivo study revealed 1.6- and 2.8-fold increases in the AUC0-inf and Cmax of the drug, respectively, in APAP-NSs-receiving animals compared to the control group. Moreover, no deaths and no abnormalities in clinical signs, body weights, and necropsy findings were detected in the dose groups up to 100 mg/kg of the 28-day repeated oral dose toxicity study in mice.

Investigating the Relationship between the Attitude Towards Infertility and Stress Coping Strategies among Couples undergoing Assisted Reproduction Treatment.

INTRODUCTION: Infertility and its treatment methods among couples have psychological and social consequences. To encounter these consequences, coping strategies are commonly used, which are influenced by various factors, such as the attitude of couples toward infertility. OBJECTIVE: This study aims to determine the relationship between attitudes toward infertility and stress-coping strategies among couples undergoing Assisted Reproduction Treatment, referring to the infertility clinic of Al-Zahra Educational Center. METHODS: This study was a cross-sectional study performed on 153 couples referred to Al-Zahra Infertility Clinic in Rasht. Three instruments (demographic questionnaire, attitude, and Lazarus coping strategies questionnaire) were used with regard to the inclusion restrictions. RESULTS: Between the two variables of individual and social information factors and the attitude of couples toward infertility, only the duration of infertility factor revealed a significant relationship (p <0.05); and in explaining the relationship between individual and social variables and coping strategies, the lack of insurance in both genders with an emotion-oriented strategy, the female infertility factor in women with the confrontational adjustment domain, and treatment in a discontinuous way in both genders have a significant relationship with the problem-oriented domain (p <0.05). Accountability and problem-solving strategies in women and an escapeavoidance strategy in infertile men have been identified as the most important predictors of attitude toward infertility. CONCLUSION: There is a relationship between attitudes toward infertility and coping strategies. However, the impact of community culture on the type of coping strategies used in this study has led to different results in some cases from other studies.

Lipase immobilization on glutaraldehyde activated graphene oxide/chitosan/cellulose acetate electrospun nanofibrous membranes and its application on the synthesis of benzyl acetate.

In this research, lipase Km12 was immobilized on the glutaraldehyde-activated graphene oxide/chitosan/cellulose acetate nanofibers (GO/Chit/CA NFs) prepared by the electrospinning method. This immobilized lipase exhibited a higher activity value than the free lipase in the acidic pH region. This enzyme showed a 10 °C shift in the maximum temperature activity. Results displayed that the Vmax value of NFs-lipase was 0.64 µmol/min, while it was gained 0.405 µmol/min for the free lipase. The activity of NFs-lipase was reserved 100% after 10 min maintaining at 60 °C, in which the free lipase only kept 75% of its original activity. Moreover, a 20% enhancement in the lipase activity was observed for NFs-lipase after 180 min of incubation at 60 °C, compared to the free enzyme. Reusability studies exhibited that the immobilized lipase well-kept 80% of its original activity after 10 cycles of reusing. Results displayed that 14% of the protein was leaked from NFs-lipase at the same condition. Transesterification results indicated that the free lipase exhibited 65% and 85% conversation level of benzyl acetate after 12 and 24 h of incubation. Besides, the immobilized lipase showed 80% and 95% conversation level at the same condition. These results indicated the high performance of free and immobilized lipase in the production of benzyl acetate for applications in the perfume and cosmetic industries.

Induced pluripotent stem cells: Generation methods and a new perspective in COVID-19 research.

Induced pluripotent stem cells (iPSCs) exhibit an unlimited ability to self-renew and produce various differentiated cell types, thereby creating high hopes for both scientists and patients as a great tool for basic research as well as for regenerative medicine purposes. The availability and safety of iPSCs for therapeutic purposes require safe and highly efficient methods for production of these cells. Different methods have been used to produce iPSCs, each of which has advantages and disadvantages. Studying these methods would be very helpful in developing an easy, safe, and efficient method for the generation of iPSCs. Since iPSCs can be generated from somatic cells, they can be considered as valuable cellular resources available for important research needs and various therapeutic purposes. Coronavirus disease 2019 (COVID-19) is a disease that has endangered numerous human lives worldwide and currently has no definitive cure. Therefore, researchers have been rigorously studying and examining all aspects of COVID-19 and potential treatment modalities and various drugs in order to enable the treatment, control, and prevention of COVID-19. iPSCs have become one of the most attractive and promising tools in this field by providing the ability to study COVID-19 and the effectiveness of drugs on this disease outside the human body. In this study, we discuss the different methods of generation of iPSCs as well as their respective advantages and disadvantages. We also present recent applications of iPSCs in the study and treatment of COVID-19.

Polysorbate-coated mesoporous silica nanoparticles as an efficient carrier for improved rivastigmine brain delivery.

Targeted delivery of neurological therapeutic to the brain has been attracting more and more attention to the treatment of central nervous system (CNS) diseases. Nonetheless, the main obstacle in this road map is the existence of a blood-brain barrier (BBB) which limits the penetration efficiency of most CNS drugs into the brain parenchyma. This present investigation describes a facile synthetic strategy to prepare a highly biocompatible calcium-doped mesoporous silica nanoparticles (MSNs) functionalized by polysorbate-80 (PS) as targeting ligand to deliver rivastigmine (RV) into the brain via crossing the BBB. The developed nanosystem was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Zeta potential, and N2-adsorption-desorption analysis. In vitro hemolysis studies were carried out to confirm the biocompatibility of the nanocarriers. Our in vivo studies in an animal model of rats showed that the RV-loaded nanosystem was able to enhance the brain-to-plasma concentration ratio, brain uptake clearance, and plasma elimination half-life of the drug compared to the free one drug following intravenous (IV) administration. The results revealed that functionalization of MSNs by PS is crucial to deliver RV into the brain, suggesting PS-functionalized MSNs could be an effective carrier to deliver RV to the brain while overcoming BBB.

Comparing shear wave elastography and fine needle aspiration in the diagnosis of solid thyroid nodules.

This descriptive study was performed on individuals who were referred to Imam Reza Hospital for fine needle aspiration biopsy (FNAB) based on the results of gray scale ultrasound and the decision of the referring physician. In addition to determining the gray scale characteristics of the nodules, shear wave elastography (SWE) was also performed and the results were recorded. These were also taken from the patients FNAB results. Finally, the findings of SWE and FNAB methods were compared and analyzed using SPSS software version 16. Based on the results presented herein, a significant relationship was observed between the results of SWE and FNA in the diagnosis of malignancy in solid thyroid nodules. This agreement was found to be higher in men (K = 0.866) than women (K = 0.849). Taken together, our data suggest that shear wave elastography can replace FNA in the diagnosis of malignancy in solid thyroid nodules.

Cross-linked Enzyme Aggregates of Fibrinolytic Protease BC1 Immobilized on Magnetic Chitosan Nanoparticles (CLEAs-Fib-mChi): Synthesis, Purification, and Characterization.

Bacterial fibrinolytic proteases achieved more attention in the prevention and treatment of cardiovascular diseases, so purification, characterization, and activity enhancement are of prime importance. In this study, a fibrinolytic serine metalloprotease was purified from the culture supernatant from Bacillus sp. BC1. It was purified to homogeneity by a two-step procedure with a 24-fold increase in specific activity and a 33.1% yield. It showed 28 kDa molecular weight, while its optimal pH and temperature were obtained 8 and 50-60 °C. The cross-link enzyme aggregates of this fibrinolytic BC1 successfully immobilized on magnetic chitosan nanoparticles. A 52% activity enhancement was obtained by immobilized enzyme at pH 6.0, compared to free protease. Km values of the free and immobilized proteases were obtained about 0.638 and 0.61 mg/ml, respectively. The free and immobilized enzymes did not show any activity concerning transferrin, γ-globulins, and hemoglobin, as blood plasma proteins. The in vitro blood clot lysis test of the free and immobilized proteases showed a maximum of 42 and 50% clot lysis, which was comparatively higher than that revealed by streptokinase and heparin at the same condition. These results indicated that the free and immobilized proteases have the potential to be effective fibrinolytic agents.

Lipase immobilization on a novel class of Zr-MOF/electrospun nanofibrous polymers: Biochemical characterization and efficient biodiesel production.

In this study, due to the favorable properties of MOF compounds and fibrous materials, new nanostructures of Zr-MOF/PVP nanofibrous composites were synthesized by electrospinning procedure. The related features of these samples were characterized by relevant analyzes, including SEM, BET surface area analysis, XRD, and FTIR spectroscopy. The final product showed significant properties such as small particle size distribution, large surface area, and high crystallinity. This strategy for producing these nanostructures could lead to new compounds as novel alternative materials for biological applications. Lipase MG10 was successfully immobilized on the mentioned nanofibrous composites and biochemically characterized. The lipase activity of free and immobilized lipases was considered by measuring the absorbance of pNPP (500 µM in 40 mM Tris/HCl buffer, pH 7.8, and 0.01% Triton X100) at 37 °C for 30 min. Different concentrations of glutaraldehyde, different crosslinking times, different times of immobilization, different enzyme loading, and different pH values have been optimized. Results showed that the optimized immobilization condition was achieved in 2.5% glutaraldehyde, after 2 h of crosslinking time, after 6 h immobilization time, using 180 mg protein/g support at pH 9.0. The immobilized enzyme was also totally stable after 180 min incubation at 60 °C. The free enzyme showed the maximum activity at pH 9.0, but the optimal pH of the immobilized lipase was shifted about 1.5 pH units to the alkaline area. The immobilized lipase showed about 2.7 folds (78%) higher stability than the free enzyme at 50 °C. Some divalent metal ions, including Cu2+ (22%), Co2+ (37%), Mg2+ (12%), Hg2+ (11%), and Mn2+ (17%) enhanced the enzyme activity of immobilized enzyme. The maximum biodiesel production (27%) from R. communis oil was obtained after 18 h of incubation by lipase MG10. The immobilized lipase displayed high potency in biodiesel production, about 83% after 12 h of incubation. These results indicated the high potency of Zr-MOF/PVP nanofibrous composites for efficient lipase immobilization.

One-pot synthesis and biochemical characterization of protease metal organic framework (protease@MOF) and its application on the hydrolysis of fish protein-waste.

A protease from Bacillus sp. CHA410 was purified and immobilized by a one-step MOF-embedded approach. The immobilized protease characterized using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The optimal pH activity of protease CHA410 and protease@MOF was obtained at pH 8.0 and 9.0, respectively. Thermostability results after 160 min incubation showed that a 25 and 41 % enhancement in the relative activity of protease@MOF observed at 60 and 70 °C, respectively, compared to free protease. Km of the free and immobilized protease@MOF in the presence of casein was 0.685 and 0.033 mg/mL, respectively. Also, Km of the free and immobilized protease@MOF in the presence of fibrin was 0.292 and 0.145 mg/mL, respectively. The Fibrinolytic activity/Caseinolytic activity ratio (F/C ratio) of the free and immobilized proteases was 0.36 and 0.43, respectively. Protease activity of both forms of the enzyme was increased in the presence of some divalent cations, including Ca2+, Mn2+, Mg2+, and Zn2+ ions, while it intensely diminished by phenylmethylsulfonyl fluoride (PMSF), proposed as serine-protease. A 10 and 82 % enhancement in protease activity of free and immobilized proteases was achieved in the presence of butanol, respectively. Storage stability results showed that the immobilized enzyme retained about 70 % of its original activity at the end of this period, while the free enzyme only showed 22 % of its initial activity. The hydrolysis degree of immobilized protease CHA410 in the hydrolysis of fish protein waste was obtained about 46 % after 2 h of incubation at 50 °C. In comparison, it was gained about 20 % for protease CHA410 at a similar situation. Finally, results indicated that the free and immobilized protease could be used in the food industry for the hydrolysis of fish protein waste.