| 1. |
- Dokhaee, Z., et al.
(författare)
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Investigation of the blends of chitosan and tragacanth as potential drug carriers for the delivery of ibuprofen in the intestine
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 43:37, s. 14917-14927
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Tidskriftsartikel (refereegranskat)abstract
- Natural polymers are reliable compounds in drug delivery systems (DDS). Herein, two series of safe and reliable polyelectrolyte hydrogels (PEHs) were prepared from two oppositely charged polysaccharides, namely tragacanth (TG) and chitosan (CS), and applied for the delivery of ibuprofen as a model drug. Considering the different interactions of CS and TG as a polycation and a polyanion, respectively, with the drug, herein, two series of PEHs were prepared, and their diversity in morphology and drug release ability were studied. The system provided a high percentage of drug loading efficiency (>90%) and was sensitive to the acidity of different media. The drug release pattern was favorable; the data showed that the slowest rate of drug release was obtained at pH = 1.2, followed by pH = 5.4, and fastest drug release occurred at a slightly basic pH (=7.4); the mechanism of drug release was studied using different kinetic models, where at pH = 1.2 and 7.4, the drug release curve best matched the zero order and the Hixson-Crowell model, and at pH = 5.4, the Weibull model represented the perfect agreement with the drug release patterns. The stability of the drug carrier was explored by fluorescence imaging. The cytotoxicity of the CS-I-T 30% and CS-T composites was evaluated towards the cultured MCF7 cells for 24 and 48 h, and no toxic effects were observed.
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| 2. |
- Ghazaie, M., et al.
(författare)
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Study on release of naproxen and metformin encapsulated in biopolymer-inorganic mesoporous matrices as controlled drug-delivery systems
- 2017
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Ingår i: Microporous and Mesoporous Materials. - : Elsevier BV. - 1387-1811. ; 244, s. 291-300
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a new methodology was applied for controlling the release of different drugs by encapsulating them in organic-inorganic hybrids via sol-gel technique. The assembled organic-inorganic hybrids had diverse BET surface area, porosity, and high heat resistance. The synthesized organic-inorganic hybrids were based on zirconium(IV) propoxide, and tetraethyl orthosilicate as precursor of inorganic network, and chitosan or N-triethylchitosan as organic or biopolymer components. In these hybrid composites, drug and biopolymer were coated with a mesoporous inorganic material. FT-IR, FE-SEM, DSC, BET, XRD techniques, and Zeta potential analysis used for investigating the formation of metformin/ chitosan@ZrO2 and sodium naproxen/N-triethylchitosan@SiO2 hybrid composites. Then for investigating the role of sol-gel process, the release of metformin and sodium naproxen in the prepared hybrid composites was investigated as model drugs. Compare to drugibiopolymer composite, incorporation of ZrO2 or SiO2 coating enhanced the drug entrapment appreciably, and naturally reduced the rate of drug release. For example, the metformin/chitosan composite without ZrO2 coating released the whole drug in less than10 h in pH 7.4 when the composite coated with ZrO2 released the entrapped drug after 25 h. (C) 2016 Elsevier Inc. All rights reserved.
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| 3. |
- Kamari, Y., et al.
(författare)
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Study on montmorillonite/insulin/TiO2 hybrid nanocomposite as a new oral drug-delivery system
- 2017
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Ingår i: Materials Science and Engineering C. - : Elsevier BV. - 0928-4931. ; 75, s. 822-828
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Tidskriftsartikel (refereegranskat)abstract
- This study was conducted in two main stages. In the first stage, drug-loaded montmorillonite nanocomposites were prepared by intercalation of insulin into the montmorillonite layers in acidic deionized (DI) water. In the second stage, to increase the release of insulin from the prepared nanocomposites they were coated with TiO2, an inorganic porous coating, by using titanium (IV) butoxide, as precursor. The prepared nanocomposites were characterized by FT-IR, XRD, FE-SEM, BET, DLS and Zeta potential analysis. After investigating the release behaviour of the nanocomposites by UV–Vis absorbance technique, the results revealed that incorporation of porous TiO2 coating increased the drug entrapment noticeably, and decreased the amount of drug release, so that nanocomposites without and with TiO2 coating released the drug after 60min and 22h in pH7.4, respectively. These results could be used in converting the insulin utilization from injection to oral. © 2017 Elsevier B.V.
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| 4. |
- Alalam, Hanna, et al.
(författare)
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A High-Throughput Method for Screening for Genes Controlling Bacterial Conjugation of Antibiotic Resistance.
- 2020
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Ingår i: mSystems. - 2379-5077. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The rapid horizontal transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high-throughput. We then mix the resistance plasmid-carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals, and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within Escherichia coli populations, by screening the Keio deletion collection in high replication. We recover all seven known chromosomal gene mutants affecting conjugation as donors and identify many novel mutants, all of which diminish antibiotic resistance transmission. We validate nine of the novel genes' effects in liquid mating assays and complement one of the novel genes' effect on conjugation (rseA). The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improve the longevity of current and future antibiotics. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.IMPORTANCE The rapid transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within E. coli populations. We recover all previously known and many novel chromosomal gene mutants that affect conjugation efficiency. The new framework holds great potential for rapid screening of compounds that decrease transmission. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.
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| 5. |
- Alalam, Hanna, et al.
(författare)
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Conjugation factors controlling F-plasmid antibiotic resistance transmission
- 2018
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Ingår i: BioRxiv. - : Cold Spring Harbor Laboratory.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The rapid horizontal transmission of many antibiotic resistance genes between bacterial host cells on conjugative plasmids is a major cause of the accelerating antibiotic resistance crisis. Preventing understanding and targeting conjugation, there currently are no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation. We introduce a novel experimental framework to screen for conjugation based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high throughput. We then mix the resistance plasmid carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explored chromosomal genes controlling F plasmid donation within E. coli populations, by screening the Keio deletion collection at high replication. We recover all six known chromosomal gene mutants affecting conjugation and identify >50 novel factors, all of which diminish antibiotic resistance transmission. We verify 10 of the novel genes' effects in a liquid mating assay. The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improves the longevity of current and future antibiotics.
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| 6. |
- Caspeta-Guadarrama, Luis, 1974, et al.
(författare)
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Altered sterol composition renders yeast thermotolerant
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6205, s. 75-78
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Tidskriftsartikel (refereegranskat)abstract
- Ethanol production for use as a biofuel is mainly achieved through simultaneous saccharification and fermentation by yeast. Operating at >= 40 degrees C would be beneficial in terms of increasing efficiency of the process and reducing costs, but yeast does not grow efficiently at those temperatures. We used adaptive laboratory evolution to select yeast strains with improved growth and ethanol production at >= 40 degrees C. Sequencing of the whole genome, genome-wide gene expression, and metabolic-flux analyses revealed a change in sterol composition, from ergosterol to fecosterol, caused by mutations in the C-5 sterol desaturase gene, and increased expression of genes involved in sterol biosynthesis. Additionally, large chromosome III rearrangements and mutations in genes associated with DNA damage and respiration were found, but contributed less to the thermotolerant phenotype.
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| 7. |
- Fouladvand, Sheedeh, 1984, et al.
(författare)
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Fault Tree Analysis, Strengths and Weaknesses
- 2010
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Ingår i: SHO2010: INTERNATIONAL SYMPOSIUM ON OCCUPATIONAL SAFETY AND HYGIENE. - 9789729950469 ; , s. 253-255
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Fault Tree Analysis (FTA) is a tool of hazard identification techniques. As a useful method it is applied in various industries, social and environmental problems for reconstruction, failure analysis, and failure frequency estimation. ETA is a graphical and logic combination of causes of a defined undesired event where Boolean algebra is used. It is a backward method which is used to think about the consequences which may occur. This analysis method is mainly used in the field of safety engineering to quantify the probability of an undesired event and is used to reconstruct it. It can also be used to reconstruct an accident. Besides its advantages, there are a number of shortcomings which imply that the method still has rooms for improvement. Among the disadvantages are the uncertainties in covering all failure modes, inaccuracy in human error in investigation of complex man-made systems and inefficiency of the tool in case of scarce or insufficient data. These problems demand some revision study to find the research questions in detail. The purpose of this paper is to conduct a literature review in order to find weaknesses and strengths of FTA to indicate a platform for future research works.
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| 8. |
- GHIACI, PAYAM, 1982, et al.
(författare)
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2-Butanol and Butanone Production in Saccharomyces cerevisiae through Combination of a B-12 Dependent Dehydratase and a Secondary Alcohol Dehydrogenase Using a TEV-Based Expression System
- 2014
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- 2-Butanol and its chemical precursor butanone (methyl ethyl ketone -MEK) are chemicals with potential uses as biofuels and biocommodity chemicals. In order to produce 2-butanol, we have demonstrated the utility of using a TEV-protease based expression system to achieve equimolar expression of the individual subunits of the two protein complexes involved in the B-12-dependent dehydratase step (from the pdu-operon of Lactobacillus reuterii), which catalyze the conversion of meso-2,3-butanediol to butanone. We have furthermore identified a NADH dependent secondary alcohol dehydrogenase (Sadh from Gordonia sp.) able to catalyze the subsequent conversion of butanone to 2-butanol. A final concentration of 4 +/- 0.2 mg/L 2-butanol and 2 +/- 0.1 mg/L of butanone was found. A key factor for the production of 2-butanol was the availability of NADH, which was achieved by growing cells lacking the GPD1 and GPD2 isogenes under anaerobic conditions.
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| 9. |
- GHIACI, PAYAM, 1982, et al.
(författare)
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Physiological adaptations of Saccharomyces cerevisiae evolved for improved butanol tolerance
- 2013
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834 .- 1754-6834. ; 6:101
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Tidskriftsartikel (refereegranskat)abstract
- Background: Butanol is a chemical with potential uses as biofuel and solvent, which can be produced by microbial fermentation. However, the end product toxicity is one of the main obstacles for developing the production process irrespective of the choice of production organism. The long-term goal of the present project is to produce 2-butanol in Saccharomyces cerevisiae. Therefore, unraveling the toxicity mechanisms of solvents such as butanol and understanding the mechanisms by which tolerant strains of S. cerevisiae adapt to them would be an important contribution to the development of a bio-based butanol production process.Results: A butanol tolerant S. cerevisiae was achieved through a series of sequential batch cultures with gradual increase of 2-butanol concentration. The final mutant (JBA-mut) tolerates all different alcohols tested at higher concentrations compared to the wild type (JBA-wt). Proteomics analysis of the two strains grown under mild butanol-stress revealed 46 proteins changing their expression by more than 1.5-fold in JBA-mut, 34 of which were upregulated. Strikingly, 21 out of the 34 upregulated proteins were predicted constituents of mitochondria. Among the non-mitochondrial up-regulated proteins, the minor isoform of Glycerol-3-phosphatase (Gpp2) was the most notable, since it was the only tested protein whose overexpression was found to confer butanol tolerance.Conclusion: The study demonstrates several differences between the butanol tolerant mutant and the wild type. Upregulation of proteins involved in the mitochondrial ATP synthesizing machinery constituents and glycerol biosynthesis seem to be beneficial for a successful adaptation of yeast cells to butanol stress.
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| 10. |
- GHIACI, PAYAM, 1982, et al.
(författare)
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Production of 2-butanol through meso-2,3-butanediol consumption in lactic acid bacteria
- 2014
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968 .- 0378-1097. ; 360:1, s. 70-75
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 2-Butanol has been an issue of industries in many areas, for example, biofuel production (as an advanced alternate fuel), fermented beverages, and food (as taste-altering component). Thus, its source of production, the biological pathway, and the enzymes involved are of high interest. In this study, 42 different isolates of lactic acid bacteria from nine different species were screened for their capability to consume meso-2,3-butanediol and produce 2-butanol. Lactobacillus brevis was the only species that showed any production of 2-butanol. Five of ten tested isolates of L.brevis were able to convert meso-2,3-butanediol to 2-butanol in a synthetic medium (SM2). However, none of them showed the same capability in a complex medium such as MRS indicating that the ability to produce 2-butanol is subject to some kind of repression mechanism. Furthermore, by evaluating the performance of the enzymes required to convert meso-2,3-butanediol to 2-butanol, that is, the secondary alcohol dehydrogenase and the diol dehydratase, it was shown that the latter needed the presence of a substrate to be expressed.
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