Bioprospecting endophytic fungi for bioactive metabolites with seed germination promoting potentials.

There is an urgent need for new bioactive molecules with unique mechanisms of action and chemistry to address the issue of incorrect use of chemical fertilizers and pesticides, which hurts both the environment and the health of humans. In light of this, research was done for this work to isolate, identify, and evaluate the germination-promoting potential of various plant species' fungal endophytes. Zea mays L. (maize) seed germination was examined using spore suspension of 75 different endophytic strains that were identified. Three promising strains were identified through screening to possess the ability mentioned above. These strains Alternaria alternate, Aspergilus flavus, and Aspergillus terreus were isolated from the stem of Tecoma stans, Delonix regia, and Ricinus communis, respectively. The ability of the three endophytic fungal strains to produce siderophore and indole acetic acid (IAA) was also examined. Compared to both Aspergillus flavus as well as Aspergillus terreus, Alternaria alternata recorded the greatest rates of IAA, according to the data that was gathered. On CAS agar versus blue media, all three strains failed to produce siderophores. Moreover, the antioxidant and antifungal potentials of extracts from these fungi were tested against different plant pathogens. The obtained results indicated the antioxidant and antifungal activities of the three fungal strains. GC-Mass studies were carried out to determine the principal components in extracts of all three strains of fungi. The three strains' fungus extracts included both well-known and previously unidentified bioactive compounds. These results may aid in the development of novel plant growth promoters by suggesting three different fungal strains as sources of compounds that may improve seed germination. According to the study that has been given, as unexplored sources of bioactive compounds, fungal endophytes have great potential.

Novel nanoconjugates of metal oxides and natural red pigment from the endophyte Monascus ruber using solid-state fermentation.

BACKGROUND: Antimicrobial resistance has emerged as a major global health threat, necessitating the urgent development of new antimicrobials through innovative methods to combat the rising prevalence of resistant microbes. With this view, we developed three novel nanoconjugates using microbial natural pigment for effective application against certain pathogenic microbes. RESULTS: A natural red pigment (RP) extracted from the endophyte Monascus ruber and gamma rays were applied to synthesize RP-ZnO, RP-CuO, and RP-MgO nanoconjugates. The synthesized nanoconjugates were characterized by different techniques to study their properties. The antimicrobial potential of these nanoconjugates was evaluated. Moreover, the antibiofilm, protein leakage, growth curve, and UV light irradiation effect of the synthesized nanoconjugates were also studied. Our results confirmed the nano-size, shape, and stability of the prepared conjugates. RP-ZnO, RP-CuO, and RP-MgO nanoconjugates showed broad antimicrobial potential against the tested bacterial and fungal pathogens. Furthermore, the RP-ZnO nanoconjugate possessed the highest activity, followed by the RP-CuO against the tested microbes. The highest % inhibition of biofilm formation by the RP-ZnO nanoconjugate. Membrane leakage of E. coli and S. aureus by RP-ZnO nanoconjugate was more effective than RP-MgO and RP-CuO nanoconjugates. Finally, UV light irradiation intensified the antibiotic action of the three nanoconjugates and RP-ZnO potential was greater than that of the RP-MgO, and RP-CuO nanoconjugates. CONCLUSION: These findings pave the way for exploiting the synthesized nanoconjugates as potential materials in biomedical applications, promoting natural, green, and eco-friendly approaches.

Gamma rays-assisted bacterial synthesis of bimetallic silver-selenium nanoparticles: powerful antimicrobial, antibiofilm, antioxidant, and photocatalytic activities.

BACKGROUND: Bimetallic nanoparticles (BNPs) has drawn a lot of attention especially during the last couple of decades. A bimetallic nanoparticle stands for a combination of two different metals that exhibit several new and improved physicochemical properties. Therefore, the green synthesis and design of bimetallic nanoparticles is a field worth exploring. METHODS: In this study, we present a green synthesis of silver nanoparticles (Ag NPs), selenium (Se) NPs, and bimetallic Ag-Se NPs using Gamma irradiation and utilizing a bacterial filtrate of Bacillus paramycoides. Different Techniques such as UV-Vis., XRD, DLS, SEM, EDX, and HR-TEM, were employed for identifying the synthesized NPs. The antimicrobial and antibiofilm activities of both the Ag/Se monometallic and bimetallic Ag-Se NPs were evaluated against some standard microbial strains including, Aspergillus brasiliensis ATCC16404, Candida albicans ATCC10231, Alternaria alternate EUM108, Fusarium oxysporum EUM37, Escherichia coli ATCC11229, Bacillus cereus ATCC15442, Klebsiella pneumoniae ATCC13883, Bacillus subtilis ATCC15442, and Pseudomonas aeruginosa ATCC6538 as a model tested pathogenic microbes. The individual free radical scavenging potentials of the synthesized Ag NPs, Se NPs, and bimetallic Ag-Se NPs were determined using the DPPH radical scavenging assay. The degradation of methylene blue (MB) dye in the presence of the synthesized Ag NPs, Se NPs, and bimetallic Ag-Se NPs was used to assess their photocatalytic behavior. RESULTS: According to the UV-Vis. spectrophotometer, the dose of 20.0 kGy that results in Ag NPs with the highest O.D. = 3.19 at 390 nm is the most effective dose. In a similar vein, the optimal dose for the synthesis of Se NPs was 15.0 kGy dose with O.D. = 1.74 at 460 nm. With a high O.D. of 2.79 at 395 nm, the most potent dose for the formation of bimetallic Ag-Se NPs is 15.0 kGy. The recorded MIC-values for Ag-Se NPs were 62.5 µg mL- 1, and the data clearly demonstrated that C. albicans was the organism that was most susceptible to the three types of NPs. The MIC value was 125 µg mL- 1 for both Ag NPs and Se NPs. In antibiofilm assay, 5 µg mL- 1 Ag-Se NPs inhibited C. albicans with a percentage of 90.88%, E. coli with a percentage of 90.70%, and S. aureus with a percentage of 90.62%. The synthesized NPs can be arranged as follows in decreasing order of antioxidant capacity as an antioxidant result: Ag-Se NPs > Se NPs > Ag NPs. The MB dye degradation in the presence of the synthesized Ag NPs, Se NPs, and bimetallic Ag-Se NPs was confirmed by the decrease in the measured absorbance (at 664 nm) after 20 min of exposure to sunlight. CONCLUSION: Our study provides insight towards the synthesis of bimetallic NPs through green methodologies, to develop synergistic combinatorial antimicrobials with possible applications in the treatment of infectious diseases caused by clinically and industrial relevant drug-resistant strains.

Myco-fabricated ZnO nanoparticles ameliorate neurotoxicity in mice model of Alzheimer's disease via acetylcholinesterase inhibition and oxidative stress reduction.

Alzheimer's disease (AD) is one of the primary health problems linked to the decrease of acetylcholine in cholinergic neurons and elevation in oxidative stress. Myco-fabrication of ZnO-NPs revealed excellent biological activities, including anti-inflammatory and acetylcholinesterase inhibitory potentials. This study aims to determine if two distinct doses of myco-fabricated ZnO-NPs have a positive impact on behavioral impairment and several biochemical markers associated with inflammation and oxidative stress in mice that have been treated by aluminum chloride (AlCl3) to induce AD. Sixty male mice were haphazardly separated into equally six groups. Group 1 was injected i.p. with 0.5 ml of deionized water daily during the experiment. Mice in group 2 received AlCl3 (50 mg/kg/day i.p.). Groups 3 and 4 were treated i.p. with 5 and 10 mg/kg/day of ZnO-NPs only, respectively. Groups 5 and 6 were given i.p. 5 and 10 mg/kg/day ZnO-NPs, respectively, add to 50 mg/kg/day AlCl3. Results showed that the AlCl3 caused an increase in the escape latency time and a reduction in the time spent in the target quadrant, indicating a decreased improvement in learning and memory. Moreover, acetylcholinesterase enzyme (AChE) activity and malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and interleukin 1ß (IL-1ß) levels were significantly increased, and the content of glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), as well as levels of serotonin and dopamine, were decreased in brain tissues only in AlCl3 treated mice. However, treatment of mice with myco-fabrication of ZnO-NPs at doses of 5 or 10 mg/kg improves learning and memory function through ameliorate all the previous parameters in the AD mice group. The low dose of 5 mg/kg is more effective than a high dose of 10 mg/kg. In accordance with these findings, myco-fabricated ZnO-NPs could enhance memory and exhibit a protective influence against memory loss caused by AlCl3.

Unlocking the biosynthetic potential of Penicillium roqueforti for hyperproduction of the immunosuppressant mycophenolic acid: Gamma radiation mutagenesis and response surface optimization of fermentation medium.

Based on the broad clinical utility of the immunosuppressant mycophenolic acid (MPA), this article aims to intensify the biosynthetic potential of Penicillium roqueforti for more effective hyperproduction of the drug. Several mutants were generated from irradiation mutagenesis and screened. Two strains (GM1013 and GM1093) presented an elevated MPA productivity with significant yield constancy over 10 subsequent generations. By investigating the effect of some phosphorous sources and mineral salts on MPA production by the two mutants, KH2 PO4 and FeSO4 ·7H2 O were most preferred by the two mutants for higher MPA production rates. Statistics-dependent experimental designs were also employed for optimizing medium components for maximum MPA production. Medium components were primarily screened using the Plackett-Burman model to demonstrate the most important components that most significantly affect MPA production. The concentrations of these significant components were then optimized through a central composite rotatable model. In conclusion, gamma-radiation mutation and response surface optimization resulted in a promising MPA productivity by P. roqueforti GM1013. To our knowledge, the MPA-yield achieved in this study (2933.32 mg L-1 ) is the highest reported by academic laboratories from P. roqueforti cultures, which could be of economic value for a prospective large industrialized application.

LCMS/MS Phytochemical Profiling, Molecular, Pathological, and Immune-Histochemical Studies on the Anticancer Properties of Annona muricata.

Annona muricate is a tropical plant that is well-known for its edible fruit of therapeutic interest. LCMS/MS analyses were applied to identify phytoconstituents of the ethanolic extract of the whole fruits and the aqueous extract of the edible fruit part, in addition to the investigation of their anticancer properties against Ehrlich ascites carcinoma (EAC) in male albino mice. LCMS/MS analyses resulted in the identification of 388 components, representing a wide array of classes of compounds, including acetogenins as the major constituents, alkaloids, flavonoids, and phenolics. Among them, four compounds were tentatively characterized as new compounds (1-4), including an acid derivative, protocatechuic-coumaroyl-quinic acid (1), and three flavonoid derivatives, dihydromyricetin galloyl hexoside (2), apigenin gallate (3), and dihydromyricetin hexouronic acid hexoside (4). Induction with EAC cells resulted in abnormalities in the gene expression of pro-apoptotic genes (Bax and caspase-3) and anti-apoptotic gene (Bcl-2) in the tumor mass. Moreover, microscopic, histopathological, and immune-histochemical examinations of the tumor mass and liver tissues exhibited extensive growth of malignant Ehrlich carcinoma cells and marked hydropic degeneration of hepatocytes and infiltration by tumor cells to liver tissue with marked inflammatory reaction. These abnormalities were markedly ameliorated aftertreatment of EAC mice with A. muricata extracts.

Construction of 2D layered TiO2@MoS2heterostructure for efficient adsorption and photodegradation of organic dyes.

In this work, heterostructures of coupled TiO2@MoS2with different phases of MoS2were synthesized via hydrothermal technique. The prepared materials were thoroughly characterized using various techniques, including XRD, SEM, transmission electron microscopy, Brunauer-Emmet-Teller, XPS, Zeta potential and UV-vis spectroscopy. The optimized nanocomposites were tested for the photocatalytic degradation of methyl Orange (MO) under visible light as well as the adsorption of Rhodamine b (RhB) and methelene blue (MB) dyes. The TiO2@1T/2H-MoS2heterostructures exhibited a narrow bandgap compared to the other studied nanomaterials. A remarkable photodegradation efficiency of TiO2@1T/2H-MoS2was observed, which completely degraded 20 ppm of MO after 60 min with high stability over four successive cycles. This can be assigned to the formation of unique heterostructures with aligned energy bands between MoS2nanosheets and TiO2nanobelts. The formation of these novel interfaces promoted the electron transfer and increased the separation efficiency of carriers, resulting in high photocatalytic degradation. Furthermore, the adsorption efficiency of TiO2@1T/2H-MoS2was unique, 20 ppm solutions of RhB and MB were removed after 1 and 2 min, respectively. The superior adsorption performance of the TiO2@1T/2H-MoS2can be attributed to its high surface area (279.9 m2g-1) and the rich concentration of active sites. The kinetics and the isothermal analysis revealed that the TiO2@1T/2H MoS2heterstructures have maximum adsorption capacity of 1200 and 970 mg g-1for RhB and MB, respectively. This study provides a powerful way for designing an effective photocatalyst and adsorbent TiO2-based nanocomposites for water remediation.

New and potent production platform of the acetylcholinesterase inhibitor huperzine A by gamma-irradiated Alternaria brassicae under solid-state fermentation.

Huperzine-A (HupA) is an emerging, powerful, and promising natural acetylcholinesterase inhibitor. Despite that, the achieved yields of HupA from microbial sources are still far from the industrial applications. Accordingly, this paper was conducted to valorize solid-state fermentation (SSF) as an efficient production platform of HupA. Four agro-industrial wastes, namely rice bran, potato peel, sugarcane bagasse, and wheat bran, were tested and screened as cultural substrates for the production of HupA by the endophytic Alternaria brassica under SSF. Maximum HupA production was attained on using rice bran moistened by Czapex's dox mineral broth. In the effort to increase the HupA titer, supplementation of the best moistening agent by different carbon and nitrogen sources was successfully investigated. Additionally, factors affecting HupA production under SSF including substrate concentration, moistening level, and inoculum concentration were optimized using response surface methodology. A Box-Behnken design was applied for generating a predictive model of the interactions between these factors. Under the optimum conditions of 15 g rice bran, inoculum concentration of 5 × 106 spores mL-1, and 60% moisture level, HupA concentration was intensified to 518.93 µg g-1. Besides, HupA production by the fungal strain was further enhanced using gamma-irradiation mutagenesis. The final HupA production was significantly intensified following exposure to 0.5 KGy gamma radiation to 1327 µg g-1, which represents a 12.85-fold increase. This is the first report on the successful production of the natural fungal metabolite HupA under SSF. Moreover, the achieved yield in this study using agro-industrial wastes may contribute to reducing the cost of HupA manufacture.Key points• Different agro-industrial by-products were tried as cultural substrates for the production of the acetylcholinesterase inhibitor HupA under SSF for the first time.• Factors affecting HupA production under SSF were optimized using response surface methodology.• The final HupA production was intensified following exposure to gamma radiation recording 1327 µg g-1, which represents a 12.85-fold increase.

Novel mycosynthesis of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles by the endophytic Aspergillus terreus and evaluation of their antioxidant and antimicrobial activities.

Several fungal endophytes were isolated and screened for their ability to biosynthesize a variety of nanoparticles (NPs), as a potentially simple and eco-friendly method with low cost. Among these fungi, a promising isolate named ORG-1 was found able to synthesize five different NPs types: Co3O4NPs, CuONPs, Fe3O4NPs, NiONPs, and ZnONPs. The ORG-1 strain was identified as Aspergillus terreus according to the morphological and molecular studies. Synthesis of these NPs was initially monitored by UV-Vis spectroscopy and further characterized by Fourier transform infrared spectroscopy. X-ray diffraction patterns revealed their crystalline structure. Dynamic light scattering analysis was applied to study the particle size distribution and stability. Transmission electron microscope studies indicated the morphology of the synthesized NPs. Additionally, the biological activities of the in vitro antioxidant and antimicrobial potentials were evaluated. Co3O4NPs, CuONPs, Fe3O4NPs, NiONPs, and ZnONPs showed promising antioxidant activity with 50% inhibitory concentrations of 85.44, 96.74, 102.41, 87.41, and 108.67 µg mL-1, respectively. The synthesized NPs exhibited potent antimicrobial activities against several plant and human pathogens. To our knowledge, this is the first report on the use of one microbial strain for the synthesis of a variety of NPs. This study suggests endophytic fungi as new and alternate platforms with an exceptional potentiality for the synthesis of NPs with promising activities. KEY POINTS: • Discovery of a promising endophytic fungus for synthesis of five different types of NPs. • Mycosynthesis and characterization of all the synthesized NPs were investigated. • The synthesized NPs showed promising antioxidant and antimicrobial activities.

Non-extractive spectrophotometric determination of memantine HCl, clomipramine HCl and fluvoxamine maleate in pure form and in pharmaceutical products by ion-pair complex formation with rose bengal.

OBJECTIVES: The objective of this work is to develop a simple, sensitive and non-extractive spectrophotometric method for the determination of memantine HCl (MEM), clomipramine HCl (CLM) and fluvoxamine maleate (FLV). MATERIAL AND METHODS: The proposed method was based on the formation of colored ion-pair complexes between the basic nitrogen of the target drugs and rose bengal (RB) dye in a weak acidic medium. RESULTS: The formed complexes were measured at 576nm for MEM, CLM and at 575nm for FLV. The reaction conditions were optimized to obtain the maximum color intensity. Beer's law was obeyed in the range of 2-20, 1-16 and 6-30µg/mL for MEM, CLM and FLV, respectively. The limit of detection (LOD) was 0.476, 0.185, 0.806 and the limit of quantitation (LOQ) was 1.443, 0.559 and 2.443 for MEM, CLM and FLV, respectively. The composition ratio of the ion-pair complexes was found to be 1:1 as determined by Job's method. CONCLUSION: The proposed method was applied successfully for the analysis of the cited drugs in pure and dosage forms. Results of the proposed method were statistically compared with the reported methods by applying student's t- and F-tests and no significant differences were observed.

Microbial acetylcholinesterase inhibitors for Alzheimer's therapy: recent trends on extraction, detection, irradiation-assisted production improvement and nano-structured drug delivery.

Neurodegenerative disorders especially Alzheimer's disease (AD) are significantly threatening the public health. Acetylcholinesterase (AChE) inhibitors are compounds of great interest which can be used as effective agents for the symptomatic treatment of AD. Although plants are considered the largest source for these types of inhibitors, the microbial production of AChE inhibitors represents an efficient, easily manipulated, eco-friendly, cost-effective, and alternative approach. This review highlights the recent advances on the microbial production of AChE inhibitors and summarizes all the previously reported successful studies on isolation, screening, extraction, and detecting methodologies of AChE inhibitors from the microbial fermentation, from the earliest trials to the most promising anti-AD drug, huperzine A (HupA). In addition, improvement strategies for maximizing the industrial production of AChE inhibitors by microbes will be discussed. Finally, the promising applications of nano-material-based drug delivery systems for natural AChE inhibitor (HupA) will also be summarized. KEY POINTS: • AChE inhibitors are potential therapies for Alzheimer's disease. • Microorganisms as alternate sources for prospective production of such inhibitors. • Research advances on extraction, detection, and strategies for production improvement. • Nanotechnology-based approaches for an effective drug delivery for Alzheimer's disease.

Production of the anticancer drug taxol by the endophytic fungus Epicoccum nigrum TXB502: enhanced production by gamma irradiation mutagenesis and immobilization technique.

Taxol, a phyto-extracted diterpenoid, is the most commercially needed drug in cancer chemotherapy. In spite of the microbial production of taxol being successful and prospective, the reported yields are still not sufficient for large-scale production. Thus, the discovery of new taxol-producing microbial strains and production enhancement methodologies such as process optimization, strain improvement, and immobilization technique are the main objectives. In this paper, a taxol-producing start strain Epicoccum nigrum TXB502 (initial yield 61.35 µg L-1) was isolated from Taxus baccata and identified by morphological and molecular tools. The optimum cultivation and nutritional conditions were assessed by testing one parameter at a time approach that resulted in 88.59% significant production increase. In addition, a stable mutant with improved productivity (40.07% yield increase in comparison with the parent strain) was successfully developed after gamma irradiation mutagenesis of the start strain. The taxol titer was further improved via testing different immobilization carriers for both spores and mycelia of this mutant. Over taxol production was achieved using alginate-immobilized mycelia with the feasibility of conducting six successive production cycles in a semi-continuous form. The final total concentration reached 8187.77 µg taxol 6 L-1 which represents approximately 22-fold increase, as compared to the initial titer of the start strain. These findings can pave the way for the prospective industrial manufacturing of taxol, as the achieved taxol production in this study is the highest reported by academic laboratories for microbial cultures. KEY POINTS: • Discovery of a new taxol-producing endophytic fungus E. nigrum TXB502 strain. • Taxol yield was successfully improved via bioprocess optimization and strain mutagenesis. • Alginate-immobilized mycelia were efficient for a semi-continuous production of taxol. • The final total concentration of taxol showed approximately 22-fold increase as compared to the initial titer.

Solid-state fermentation for enhanced production of selenium nanoparticles by gamma-irradiated Monascus purpureus and their biological evaluation and photocatalytic activities.

Selenium nanoparticles (SeNPs) were successfully synthesized using the culture extract of Monascus purpureus ATCC16436 grown on sugarcane bagasse under solid-state fermentation. The rapid synthesis of SeNPs was completed after 30 min as confirmed by UV-Vis spectroscopy. Functional groups present in the synthesized SeNPs samples were confirmed by Fourier transform infrared spectroscopy. The synthesized SeNPs showed a single-phase crystalline structure. Transmission electron microscope revealed the spherical shape and the mean particle size was 46.58 nm. Dynamic light scattering analysis showed that the synthesized SeNPs were monodispersed and the recorded polydispersity index value was 0.205. Zeta potential value of - 24.01 mV indicated the high stability of SeNPs. Besides, the biological activities of antioxidant, anticancer and antimicrobial as well as the photocatalytic activities were also studied. SeNPs showed promising antioxidant activity with 50% inhibitory concentration of 85.92 µg mL-1. Based on the MTT assay, SeNPs inhibited the proliferation of normal human melanocytes, human breast and liver cancer cell lines with 50% inhibitory concentrations of 45.21, 61.86 and 200.15 µg mL-1, respectively. SeNPs showed broad spectrum of antimicrobial potential against the tested human and plant pathogens. SeNPs showed efficient degradation of methylene blue dye. Moreover, the effect of gamma irradiation on the production enhancement of SeNPs was also adopted. Exposure of the fungal spores to gamma rays at 1000 Gy increased the yield of SeNPs to approximately fivefold. Hence, this study suggests a new and alternate approach with the excellent biotechnological potentiality for the production of SeNPs.

Semi-continuous production of the anticancer drug taxol by Aspergillus fumigatus and Alternaria tenuissima immobilized in calcium alginate beads.

Taxol is the most profitable drug ever developed in cancer chemotherapy; however, the market demand for the drug greatly exceeds the supply that can be sustained from its natural sources. In this study, Aspergillus fumigatus TXD105-GM6 and Alternaria tenuissima TER995-GM3 were immobilized in calcium alginate beads and used for the production of taxol in shake flask cultures. In an effort to increase the taxol magnitude, immobilization conditions were optimized by response surface methodology program (RSM). The optimum levels of alginate concentration, calcium chloride concentration, and mycelium fresh weight were 5%, 4%, and 15% (w/v), respectively. Under these conditions, taxol production by the respective fungal strains was intensified to 901.94 µg L-1 and 529.01 µg L-1. Moreover, the immobilized mycelia of both strains were successfully used in the repeated production of taxol for six different fermentation cycles. The total taxol concentration obtained in all cycles reached 4540.14 µg L-1 by TXD105-GM6 and 2450.27 µg L-1 by TER995-GM3 strain, which represents 7.85- and 6.31-fold increase, as compared to their initial titers. This is the first report on the production of taxol in semi-continuous fermentation. To our knowledge, the taxol productivity achieved in this study is the highest reported by academic laboratories for microbial cultures which indicates the future possibility to reduce the cost of taxol production.

Fracture Resistance of Endodontically Treated Teeth Restored with Fiber Posts Luted with Composite Core Materials.

AIM: This study aimed to investigate the influence of using dual-cure composite core materials for fiber post luting on the fracture resistance of endodontically treated maxillary central incisors. MATERIALS AND METHODS: Fifty sound and recently extracted maxillary central incisors were endodontically treated and distributed into five groups. In the control group, access cavities were restored with the composite resin. Experimental groups had the coronal structure trimmed 2 mm above the cementoenamel junction. Teeth were restored with fiber posts and different combinations of luting and core materials: RelyX Unicem for post luting and MultiCore for core buildup; MultiCore for post luting and core buildup; RelyX Unicem for post luting and LuxaCore for core buildup; or LuxaCore for post luting and core buildup. All teeth were restored with zirconium crowns and subjected to thermocycling (6000 cycles 5/55°C). Loading of the teeth was applied at 135° to the palatal surface, using a universal testing machine at a cross-speed of 0.5 mm/minute until failure. The mode of failure was analyzed under a digital microscope. RESULTS: The fracture resistance of the control group was significantly higher than the experimental groups (p < 0.05). There was no significant difference between the experimental groups (p > 0.05). All teeth demonstrated nonrestorable failures. CONCLUSION: With the presence of the ferrule effect and crown restoration, the selected materials for post luting and core buildup have no significant influence on the fracture resistance of the endodontically treated teeth. CLINICAL SIGNIFICANCE: The use of the same dual-cure composite core materials for fiber post luting and core buildup would simplify the clinical procedure without enhancement of the fracture resistance of the endodontically treated tooth.

Degradation of pristine and oxidized single wall carbon nanotubes by CYP3A4.

Carbon nanotubes (CNTs) are a class of carbon based nanomaterials which have attracted substantial attention in recent years as they exhibit outstanding physical, mechanical and optical properties. In the last decade many studies have emerged of the underlying mechanisms behind CNT toxicity including malignant transformation, the formation of granulomas, inflammatory responses, oxidative stress, DNA damage and mutation. In the present investigation, we studied the biodegradation of single-walled carbon nanotubes (SWCNTs) by Cytochrome P450 enzymes (CYP3A4) through using Raman spectroscopy. CYP3A4 is known isozyme accountable for metabolizing various endogenous and exogenous xenobiotics. CYP3A4 is expressed dominantly in the liver and other organs including the lungs. Our results suggest that CYP3A4 has a higher affinity for p-SWNTs compared to c-SWNTs. HEK293 cellular viability was not compromised when incubated with SWNT. However, CYP3A4 transfected HEK293 cell line showed no digestion of c-SWNTs after incubation for 96 h. Cellular uptake of c-SWNTs was observed by electron microscopy and localization of c-SWNTs was confirmed in endosomal vesicles and in the cytoplasm. This is the first study CYP3A4 degrading both p-SWNTs and c-SWNTs in an in vitro setup. Interestingly, our results show that CYP3A4 is more proficient in degrading p-SWNTs than c-SWNTs. We also employed computational modeling and docking assessments to develop a further understanding of the molecular interaction mechanism.

Strain improvement and immobilization technique for enhanced production of the anticancer drug paclitaxel by Aspergillus fumigatus and Alternaria tenuissima.

UV and gamma irradiation mutagenesis was applied on Aspergillus fumigatus and Alternaria tenuissima in order to improve their producing ability of paclitaxel. Among the screened mutants, two stable strains (designated TXD105-GM6 and TER995-GM3) showed the maximum paclitaxel production. Paclitaxel titers of the two respective mutants were dramatically intensified to 1.22- and 1.24-fold, as compared by their respective parents. Immobilization using five different entrapment carriers of calcium alginate, agar-agar, Na-CMC, gelatin, and Arabic gum was successfully applied for production enhancement of paclitaxel by the two mutants. The immobilized cultures were superior to free-cell cultures and paclitaxel production by the immobilized mycelia was much higher than that of the immobilized spores using all the tried carriers. Moreover, calcium alginate gel beads were found the most conductive and proper entrapment carrier for maximum production of paclitaxel. The feasibility of the paclitaxel production by the immobilized mycelia as affected by incubation period, medium volume, and number of beads per flask was adopted. Under the favorable immobilization conditions, the paclitaxel titers were significantly intensified to 1.31- and 1.88-fold by the respective mutants, as compared by their free cultures. The obtained paclitaxel titers by the immobilized mycelia of the respective mutants (694.67 and 388.65 µg L-1) were found promising in terms of fungal production of paclitaxel. Hence, these findings indicate the future possibility to reduce the cost of producing paclitaxel and suggest application of the immobilization technique for the biotechnological production of paclitaxel at an industrial scale.

Development and application of degradation kinetics of thin layer chromatographic densitometry and conductometric methods for butoconazole nitrate determination.

Two simple methods were developed for determination of butoconazole nitrate (BN). The first developed method was stability-indicating HPTLC-densitometric method (method A) which is based on the quantitative densitometric separation of butoconazole nitrate (BN) from its degradation products on silica gel 60 F254 and measurement of the bands at 290nm. The developed stability study of BN was performed under different stress conditions including oxidative, hydrolytic, thermal and photolytic. Degradation was observed under acidic hydrolytic and oxidative conditions. Moreover, the HPTLC method was used to study the kinetics of BN acid degradation, determining as first order kinetics. The degradation rate constant of BN was found to be 0.076 hr-1 and t 1/2 value was determined at 9.12 hr in acidic medium. The second method (Method B) was conductometric method which is based on the reaction of BN with phosphotungstic acid (PTA) to form an ion associate in 50% methanol-water system. Validation of the proposed methods was carried out. All proposed methods were successfully applied for the commercial dosage form of BN. Statistical analysis of the results has been carried out revealing high accuracy and good precision.

The relationship between resilience, happiness, and life satisfaction in dental and medical students in Jeddah, Saudi Arabia.

OBJECTIVES: Few studies have investigated positive psychological health among medical and dental students. This study aimed to investigate the relationship between resilience, satisfaction with life, and happiness among medical and dental students in private colleges in Jeddah, Saudi Arabia. MATERIALS AND METHODS: A total of 607 participants, from 3rd-year students to interns, were involved in a cross-sectional study. Data were collected through a self-reported questionnaire. Resilience was measured by the Resilience Scale-14, happiness was measured by the subjective happiness scale, and life satisfaction was measured by the satisfaction With life scale. Data were analyzed by t-test, ANOVA, and linear regression. RESULTS: There was a significant correlation between resilience and life satisfaction (P < 0.001), and between resilience and happiness (P < 0.001). There were 66.3% who have resilience below average and 24.7% who have satisfaction with life below average. Resilience was higher in females, dental students, and students with high family income than it was in the opposite subgroups. CONCLUSION: Students with high resilience are happier and more satisfied with their lives. Establishing programs to help students improve their resilience is recommended.