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Journal of Advanced Pharmaceutical... 2023Besides adenovirus, pneumonia can also be caused by bacteria. One of the most common bacteria causing the pneumonia is e. Currently, treatment by antibiotics has been...
Besides adenovirus, pneumonia can also be caused by bacteria. One of the most common bacteria causing the pneumonia is e. Currently, treatment by antibiotics has been widely used. Nevertheless, the increasing failure of existing antibiotics because of antibiotic resistance resulted by bacterial pathogens has become a serious problem to human health. Hence, there is a need for a new antibacterial potential agent against as an alternative treatment to the pneumonia to prevent the risk of a severe pneumonia for both healthy people and those already infected with the pneumonia. This study, therefore, investigated the antibacterial activity of some selected plants (, and ) against e. In this study, samples were extracted successively by cold maceration using hexane and methanol. Antibacterial activity was determined by well and disc diffusion methods. Each fraction was prepared by two-fold dilutions from 20 mg/mL to 0.156 mg/mL. All data were analyzed in triplicate replication and presented as mean values ± standard deviation. Results showed that all methanol fractions of selected plants had antibacterial activity against , and well-diffusion method showed better antibacterial results compared to the agar well-diffusion method. The strongest activity was obtained by methanol fraction of leaf, followed by leaf, bark, leaf, leaf, and leaf with the minimum inhibitory concentrations (MICs) value between 0.625 and 5.0 mg/mL. Phytochemical screening revealed that all methanol fractions were rich in flavonoid content, which could have contributed to their antibacterial activity.
PubMed: 37692002
DOI: 10.4103/JAPTR.JAPTR_183_23 -
PloS One 2023The high pressure in some gas wells, such as those in the Xushen gas field in Daqing, China, makes them susceptible to freezing and hydrate blockages. Downhole...
The high pressure in some gas wells, such as those in the Xushen gas field in Daqing, China, makes them susceptible to freezing and hydrate blockages. Downhole throttling technology is widely used to reduce costs during well construction, however, due to the limitations of temperature, pressure and depth structure, this technology is sometime applied independently in some gas wells in which freezing and blockages are a frequent problem that can seriously affect production capacity. Moreover, artificial alcohol injection of 'passive plugging' to prevent hydrate formation not only consumes significant amounts of methanol but its efficiency is also dependent on factors such as weather, personnel and equipment, so it is not a continuous solution. In order to solve the above problems, the mechanism of hydrate formation was analyzed in this study, from which a combined mechanical and chemical hydrate control process was developed. OLGA software was used to design the process parameters of the novel mechanical and chemical inhibition technology for hydrate prevention and control, and also to simulate and analyze the wellhead temperature, pressure and hydrate generation once the process was implemented. Based on the results of the parameters calculation, the downhole throttle and hydrate inhibitor automatic filling device are used to realize the functions of downhole throttle depressurization and hydrate inhibitor continuous filling, reduce the wellhead pressure and hydrate generation temperature, and ensure the continuous production of gas well. This novel combination process was subsequently tested in three wells in the Daqing gas oilfield. Measurements showed that the average daily gas increase from a single well was 0.5×104m3, methanol consumption was reduced from the original maximum daily amount of 1750 kg to just 60 kg, the manual maintenance workload was reduced by 80%, and the rate of the well openings was increased from 45% to 100%. These results proved that this technology is feasible and efficient for applications in gas wells with high downhole pressure and low wellhead temperature, and, thus, provides important technical support for the prevention of gas hydrate and improvement of gas well production.
Topics: Methanol; Oil and Gas Fields; China; Cold Temperature; Technology
PubMed: 38060546
DOI: 10.1371/journal.pone.0295356 -
International Journal of Molecular... Sep 2023Pectin is a complex polysaccharide that forms a substantial proportion of the plant's middle lamella of forage ingested by grazing ruminants. Methanol in the rumen is...
Pectin is a complex polysaccharide that forms a substantial proportion of the plant's middle lamella of forage ingested by grazing ruminants. Methanol in the rumen is derived mainly from methoxy groups released from pectin by the action of pectin methylesterase (PME) and is subsequently used by rumen methylotrophic methanogens that reduce methanol to produce methane (CH). Members of the genus are key pectin-degrading rumen bacteria that contribute to methanol formation and have important roles in fibre breakdown, protein digestion, and the biohydrogenation of fatty acids. Therefore, methanol release from pectin degradation in the rumen is a potential target for CH mitigation technologies. Here, we present the crystal structures of PMEs belonging to the carbohydrate esterase family 8 (CE8) from and , determined to a resolution of 2.30 Å. These enzymes, like other PMEs, are right-handed β-helical proteins with a well-defined catalytic site and reaction mechanisms previously defined in insect, plant, and other bacterial pectin methylesterases. Potential substrate binding domains are also defined for the enzymes.
Topics: Animals; Methanol; Rumen; Butyrivibrio; Carboxylesterase; Bacteria; Pectins
PubMed: 37762041
DOI: 10.3390/ijms241813738 -
Microbial Cell Factories Jun 2024Heme-incorporating peroxygenases are responsible for electron transport in a multitude of organisms. Yet their application in biocatalysis is hindered due to their...
BACKGROUND
Heme-incorporating peroxygenases are responsible for electron transport in a multitude of organisms. Yet their application in biocatalysis is hindered due to their challenging recombinant production. Previous studies suggest Komagataella phaffi to be a suitable production host for heme-containing enzymes. In addition, co-expression of helper proteins has been shown to aid protein folding in yeast. In order to facilitate recombinant protein expression for an unspecific peroxygenase (AnoUPO), we aimed to apply a bi-directionalized expression strategy with Komagataella phaffii.
RESULTS
In initial screenings, co-expression of protein disulfide isomerase was found to aid the correct folding of the expressed unspecific peroxygenase in K. phaffi. A multitude of different bi-directionalized promoter combinations was screened. The clone with the most promising promoter combination was scaled up to bioreactor cultivations and compared to a mono-directional construct (expressing only the peroxygenase). The strains were screened for the target enzyme productivity in a dynamic matter, investigating both derepression and mixed feeding (methanol-glycerol) for induction. Set-points from bioreactor screenings, resulting in the highest peroxygenase productivity, for derepressed and methanol-based induction were chosen to conduct dedicated peroxygenase production runs and were analyzed with RT-qPCR. Results demonstrated that methanol-free cultivation is superior over mixed feeding in regard to cell-specific enzyme productivity. RT-qPCR analysis confirmed that mixed feeding resulted in high stress for the host cells, impeding high productivity. Moreover, the bi-directionalized construct resulted in a much higher specific enzymatic activity over the mono-directional expression system.
CONCLUSIONS
In this study, we demonstrate a methanol-free bioreactor production strategy for an unspecific peroxygenase, yet not shown in literature. Hence, bi-directionalized assisted protein expression in K. phaffii, cultivated under derepressed conditions, is indicated to be an effective production strategy for heme-containing oxidoreductases. This very production strategy might be opening up further opportunities for biocatalysis.
Topics: Promoter Regions, Genetic; Saccharomycetales; Bioreactors; Recombinant Proteins; Mixed Function Oxygenases; Methanol
PubMed: 38879507
DOI: 10.1186/s12934-024-02451-9 -
Applied Microbiology and Biotechnology Feb 2024Pyrroloquinoline quinone (PQQ) is a natural antioxidant with diverse applications in food and pharmaceutical industries. A lot of effort has been devoted toward the...
Pyrroloquinoline quinone (PQQ) is a natural antioxidant with diverse applications in food and pharmaceutical industries. A lot of effort has been devoted toward the discovery of PQQ high-producing microbial species and characterization of biosynthesis, but it is still challenging to achieve a high PQQ yield. In this study, a combined strategy of random mutagenesis and adaptive laboratory evolution (ALE) with fermentation optimization was applied to improve PQQ production in Hyphomicrobium denitrificans H4-45. A mutant strain AE-9 was obtained after nearly 400 generations of UV-LiCl mutagenesis, followed by an ALE process, which was conducted with a consecutive increase of oxidative stress generated by kanamycin, sodium sulfide, and potassium tellurite. In the flask culture condition, the PQQ production in mutant strain AE-9 had an 80.4% increase, and the cell density increased by 14.9% when compared with that of the initial strain H4-45. Moreover, batch and fed-batch fermentation processes were optimized to further improve PQQ production by pH control strategy, methanol and HO feed flow, and segmented fermentation process. Finally, the highest PQQ production and productivity of the mutant strain AE-9 reached 307 mg/L and 4.26 mg/L/h in a 3.7-L bioreactor, respectively. Whole genome sequencing analysis showed that genetic mutations in the ftfL gene and thiC gene might contribute to improving PQQ production by enhancing methanol consumption and cell growth in the AE-9 strain. Our study provided a systematic strategy to obtain a PQQ high-producing mutant strain and achieve high production of PQQ in fermentation. These practical methods could be applicable to improve the production of other antioxidant compounds with uncleared regulation mechanisms. KEY POINTS: • Improvement of PQQ production by UV-LiCl mutagenesis combined with adaptive laboratory evolution (ALE) and fermentation optimization. • A consecutive increase of oxidative stress could be used as the antagonistic factor for ALE to enhance PQQ production. • Mutations in the ftfL gene and thiC gene indicated that PQQ production might be increased by enhancing methanol consumption and cell growth.
Topics: Antioxidants; PQQ Cofactor; Hydrogen Peroxide; Methanol; Oxidative Stress; Hyphomicrobium
PubMed: 38349428
DOI: 10.1007/s00253-024-13053-1 -
BMC Complementary Medicine and Therapies Apr 2024A study carried out by World Health Organization revealed that around 80% of individuals globally depends on herbal forms of medication with 40% of pharmaceutical...
BACKGROUND
A study carried out by World Health Organization revealed that around 80% of individuals globally depends on herbal forms of medication with 40% of pharmaceutical products being sourced from medicinal plants. The study objective was to evaluate the phytochemicals composition, in vitro antimicrobial and antioxidant properties of the leaves of Terminalia catappa L. aqueous and methanolic extracts.
METHODS
Antimicrobial activity was analyzed by disk diffusion, the minimum inhibitory concentration in-vitro assays with ciprofloxacin as the standard for antibacterial assay while nystatin for antifungal assay. Ferric reducing antioxidant power and 2,2-diphenyl-1-picryl-hydrazyl-hydrate assays were used for the evaluation of antioxidant properties of the crude extracts while the groups responsible for this activity identified using Fourier transform infrared spectrophotometer.
RESULTS
The study found that the leaves of Terminalia catappa contained alkaloids, tannins, steroids, cardiac glycosides, flavonoids, phenols, saponins, and coumarins, but terpenoids were absent. Presence of functional groups associated with this class of compounds such as OH vibrational frequencies were observed in IR spectrum of the crude extracts. Methanolic extract from Terminalia catappa exhibited greater antibacterial properties against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, whereas aqueous extract displayed greater antibacterial activity against Bacillus subtilis for all concentrations tested. The amount of the sample that scavenged 50 percent of DPPH (IC50) was found to be 8.723, 13.42 and 13.04 µg/mL for L-ascorbic acid, Terminalia catappa L. methanolic and aqueous extracts respectively. The antimicrobial and antioxidant activities varied with the extract concentration and solvent used in extractions.
CONCLUSION
Terminalia catappa L. leaves are prospective for use as a source of therapeutic agents that could lead to the advancement of new antimicrobial and antioxidant products.
Topics: Humans; Antioxidants; Methanol; Terminalia; Plant Extracts; Prospective Studies; Anti-Infective Agents; Anti-Bacterial Agents; Phytochemicals; Water
PubMed: 38566161
DOI: 10.1186/s12906-024-04449-7 -
Molecules (Basel, Switzerland) Aug 2023This paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the...
This paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the solvents that differed in their polarity (dichloromethane, acetonitrile, and methanol), including three methods of sample preparation using different pre-dissolving solvents such as dimethyl sulfoxide or chloroform. In the course of the research, it was found that there are strong interactions between the tested compounds and DMSO, which was visible as a change in the maximum emission band (λ) of the neat 3-imino-1,8-naphthalimides (λ = 470-480 nm) and between the compounds and DMSO (λ = 504-514 nm). The shift of the emission maximum that was associated with the presence of a small amount of DMSO in the sample was as much as 41 nm. In addition, the susceptibility of imines to hydrolysis in the methanol/water mixture with increasing water content and in the methanol/water mixture (/; 1:1) in the pH range from 1 to 12 was discussed. The studies showed that the compounds are hydrolysed in the CHOH/HO system in an acidic environment (pH in the range of 1 to 4). In addition, it was found that partial hydrolysis occurs in systems with an increased amount of water, and its degree may depend on the type of substituent on the imine bond. The compounds tended to quench the emission (ACQ) in the aggregated state and increase the emission related to the protonation of the imine bond. Moreover, it was found that the substituent in the imine bonds influenced a compound's individual photophysical properties. Biological tests, including cytotoxicity studies and cellular localisation, were also performed for all of the molecules. All of the tested compounds exhibited green fluorescence in the MCF-7 cells and showed co-localisation in the mitochondria, endoplasmic reticulum, and lysosome. The obtained photophysical and biological results indicate the promising potential use of the tested compounds as cellular dyes.
Topics: Dimethyl Sulfoxide; Methanol; Naphthalimides; Fluorescent Dyes; Solvents; Imines; Ionophores
PubMed: 37687082
DOI: 10.3390/molecules28176255 -
Chemical Science Aug 2023Thorium complexes decorated with 5-, 6-, and 7-membered -heterocyclic iminato ligands containing mesityl wingtip substitutions have been synthesized and fully...
Thorium complexes decorated with 5-, 6-, and 7-membered -heterocyclic iminato ligands containing mesityl wingtip substitutions have been synthesized and fully characterized. These complexes were found to be efficient in the hydroboration of cyclic and linear organic carbonates with HBpin or 9-BBN promoting their decarbonylation and producing the corresponding boronated diols and methanol. In addition, the hydroboration of CO breaks the molecule into "CO" and "O" forming boronated methanol and pinBOBpin. Moreover, the demanding depolymerization of polycarbonates to the corresponding boronated diols and methanol opens the possibility of recycling polymers for energy sources. Increasing the core ring size of the ligands allows a better performance of the complexes. The reaction proceeds with high yields under mild reaction conditions, with low catalyst loading, and short reaction times, and shows a broad applicability scope. The reaction is achieved the recycling of a high-energy Th-H moiety from a stable Th-OR motif. Experimental evidence and DFT calculations corroborate the formation of the thorium hydride species and the reduction of the carbonate with HBpin to the corresponding Bpin-protected alcohols and HCOBpin through the formate and acetal intermediates.
PubMed: 37576386
DOI: 10.1039/d3sc01700a -
Molecules (Basel, Switzerland) Nov 2023Current demands for the development of suitable biocatalysts showing high process performance is stimulated by the need to replace current chemical synthesis with...
Current demands for the development of suitable biocatalysts showing high process performance is stimulated by the need to replace current chemical synthesis with cleaner alternatives. A drawback to the use of biocatalysts for unique applications is their low performance in industrial conditions. Hence, enzymes with improved performance are needed to achieve innovative and sustainable biocatalysis. In this study, we report the improved performance of an engineered acetyl xylan esterase (BaAXE) in a hydrophilic organic solvent. The structure of BaAXE was partitioned into a substrate-binding region and a solvent-affecting region. Using a rational design approach, charged residues were introduced at protein surfaces in the solvent-affecting region. Two sites present in the solvent-affecting region, A12D and Q143E, were selected for site-directed mutagenesis, which generated the mutants MUT12, MUT143 and MUT12-143. The mutants MUT12 and MUT143 reported lower Km (0.29 mM and 0.27 mM, respectively) compared to the wildtype (0.41 mM). The performance of the mutants in organic solvents was assessed after enzyme incubation in various strengths of alcohols. The mutants showed improved activity and stability compared to the wild type in low strengths of ethanol and methanol. However, the activity of MUT143 was lost in 40% methanol while MUT12 and MUT12-143 retained over 70% residual activity in this environment. Computational analysis links the improved performance of MUT12 and MUT12-143 to novel intermolecular interactions that are absent in MUT143. This work supports the rationale for protein engineering to augment the characteristics of wild-type proteins and provides more insight into the role of charged residues in conferring stability.
Topics: Methanol; Alcohols; Mutagenesis, Site-Directed; Solvents; Enzyme Stability
PubMed: 37959811
DOI: 10.3390/molecules28217393 -
Nanomaterials (Basel, Switzerland) Sep 2023Previous reports have shown that it is difficult to improve the methanol adsorption performance of nitrogen and oxygen groups due to their low polarity. Here, we first...
Previous reports have shown that it is difficult to improve the methanol adsorption performance of nitrogen and oxygen groups due to their low polarity. Here, we first prepared porous carbon with a high specific surface area and large pore volume using benzimidazole as a carbon precursor and KOH as an activating agent. Then, we improved the surface polarity of the porous carbon by doping with Lithium (Li) to enhance the methanol adsorption performance. The results showed that the methanol adsorption capacity of Li-doped porous carbon reached 35.4 mmol g, which increased by 57% compared to undoped porous carbon. Molecular simulation results showed that Li doping not only improved the methanol adsorption performance at low pressure, but also at relatively high pressure. This is mainly because Li-modified porous carbon has higher surface polarity than nitrogen and oxygen-modified surfaces, which can generate stronger electrostatic interactions. Furthermore, through density functional theory (DFT) calculations, we determined the adsorption energy, adsorption distance, and charge transfer between Li atom and methanol. Our results demonstrate that Li doping enhances the adsorption energy, reduces the adsorption distance, and increases the charge transfer in porous carbon. The mechanism of methanol adsorption by Li groups was revealed through experimental and theoretical calculations, providing a theoretical basis for the design and preparation of methanol adsorbents.
PubMed: 37764593
DOI: 10.3390/nano13182564