Range Of pH Values Research Articles

Formation of Coconut Oil By–Product Protein Concentrate–Pectin Through Electrostatic Interaction to Improve Emulsifying Properties

Coconut oil has been rising in popularity because of its health benefits. Coconut oil by-product or <em>blondo</em> is obtained during wet processing for virgin coconut oil production. It has a high protein content and can be utilized as an emulsifier in food products. This research aimed to examine the effect of pH, protein and pectin concentration on the stability and emulsification properties of heat-treated <em>blondo</em> protein concentrate-pectin complexes. The best conditions of pH, pectin and protein concentration for forming <em>blondo</em> protein concentrate-pectin complexes through electrostatic interaction were obtained by mixing <em>blondo</em> protein concentrate solution (0.5 to 1.5 wt%) with pectin (0.1 to 0.35 wt%) at different pH conditions (3 to 5). These particles were tested for emulsifying activity, stability and heat stability (85±2 °C; 15 minutes). Complexes formed using 0.5 wt% protein and 0.35 wt% pectin at pH 4 obtained from these experiments had the best zeta potential value and particle size, respectively -25.88 mV and 192.92 nm. Complexation between protein and pectin enhanced the emulsion activity index (EAI), emulsion stability index (ESI) and protection of self-aggregation protein during heating. Complexes that were formed remain stable across a range of pH values (pH 4 to 7). Thus, <em>blondo</em> protein concentrate-pectin complexes formed in this research through electrostatic interaction have better functional properties than the <em>blondo</em> protein concentrate before complexation. Emulsions created using <em>blondo</em> protein concentrate-pectin complexes through electrostatic interaction also had a higher value of emulsifying activity, stability and heat stability than emulsions with <em>blondo</em> protein concentrate alone.

Effect of Electronic Cigarette Liquid pH on Retention of 11C-Nicotine in a Respiratory Tract Model.

Based on our preliminary 11C-nicotine positron emission tomography (PET) imaging studies in humans, we speculated that greater deposition of nicotine in the respiratory tract from electronic cigarettes compared to combustible cigarettes could result from the alkaline pH of typical aerosol-producing electronic cigarette liquids (e-liquids). To address this hypothesis, we assessed the effect of e-liquid pH on the retention of nicotine in vitro using 11C-nicotine, PET, and a human respiratory tract model of nicotine deposition. A single 2-second 35-mL puff was delivered to a human respiratory tract cast from a 2.8-Ohm cartomizer at 4.1 volts. Immediately after the puff, a 2-second 700-mL air wash-in volume was administered. E-liquids (glycerol and propylene glycol 50/50 vol/vol) containing 24 mg/mL nicotine were mixed with 11C-nicotine. Deposition (retention) of nicotine was assessed using a GE Discovery MI DR PET/CT scanner. Eight e-liquids with different pH values (range 5.3-9.6) were investigated. All experiments were performed at room temperature and at a relative humidity of 70%-80%. Retention of nicotine in the respiratory tract cast was pH dependent and the pH-sensitive component of the retention was well described by a sigmoid curve. In total, 50% of the maximal pH-dependent effect was observed at pH 8.0, which is close to the pKa2 of nicotine. The retention of nicotine in the respiratory tract conducting airways is dependent on the e-liquid pH. Lowering the e-liquid pH reduces retention of nicotine. Nonetheless, reduction of the pH below 7 has little effect, consistent with the pKa2 of protonated nicotine. Similar to combustible cigarettes, the retention of nicotine in the human respiratory tract from consumption of electronic cigarettes may have some health consequences and affect nicotine dependence. Here we demonstrated that the retention of nicotine in the respiratory tract is dependent on the e-liquid pH, and lowering pH reduces retention of nicotine in conducting airways of the respiratory tract. Therefore, e-cigarettes with low pH values would result in reduced respiratory tract nicotine exposure and faster delivery of nicotine to the central nervous system (CNS). The latter can be associated with e-cigarette abuse liability and the effectiveness of e-cigarettes as substitutes for combustible cigarettes.

18β-Glycyrrhetinic acid derivative-based metallo-hydrogels with highly selective and sensitive for histidine detection

Quantitative detection of His has aroused great interest in disease diagnosis since abnormal histidine (His) metabolism would cause a variety of serious diseases. However, exploiting a strategy with facile, highly selective, sensitive sensing and low-cost to monitor His remains a challenge. In this study, a series of novel metallo-hydrogels were successfully constructed, which were composed of 18β-glycyrrhetinic acid (GA) derivative (GA-O-09) with rare earth metal ions (Ce3+, Tb3+, Eu3+ and La3+). In addition, these metallo-hydrogels possessed excellent thermodynamics stability with the gel melting temperature (Tgel) ranging from 62.4 ± 0.49 °C to 67.4 ± 0.49 °C and remarkable pH stability over a range of pH values of 3–10. Interestingly, the Histidine (His)-loaded GA-O-09/Eu3+ hydrogel and the His-loaded GA-O-09/La3+ hydrogel displayed extraordinary fluorescence enhancement, in which the lowest fluorescence response concentrations (LODs) of the His-loaded GA-O-09/Eu3+ hydrogel and the His-loaded GA-O-09/La3+ hydrogel were 1.14 × 10-8 and 1.07 × 10-8 M, respectively. Therefore, the result showed that the study of the GA-O-09/Eu3+ and GA-O-09/La3+ hydrogels could provide a potential application for highly selective and sensitive detection for His.

Enhancing charge transfer efficiency of cerium-iron oxides via Co regulated oxygen vacancies to boost peroxymonosulfate activation for tetracycline degradation

Enhancing the charge transfer efficiency and accelerating the redox cycle are effective approaches for improving the ability of catalysts to activate peroxymonosulfate (PMS). Herein, cobalt regulated cerium-iron oxides (CFO-Co) were constructed successfully. Cobalt doping significantly reduces the particle size of cerium-iron oxides (CFO) and increases the concentration of oxygen vacancies, which further enhances the charge transfer efficiency and accelerates the redox cycle to generate more reactive oxygen species (ROS). Therefore, CFO-Co exhibits boosted PMS activation which could degrade 71.2% of tetracycline (TC) within 3 min and the rate constant can be up to 0.39 min−1, which is 5.6 times higher than that of pure CFO. In the meantime, CFO-Co still showed excellent catalytic performance under wide range of pH values, temperature, various polluted water bodies, coexisting ions, and long-term cycling conditions. Moreover, CFO-Co displayed easy catalysts recovery for its magnetic behavior. DFT calculation shows that the introduction of cobalt can significantly reduce the adsorption energy of PMS on the catalyst and lengthen peroxy bond (IO-O), which promotes the activation of PMS to produce ROS. The mechanism studies demonstrated that 1O2, ∙OH, O2–∙ and SO4−∙ generated during the reaction were the main active species. The possible degradation pathways and the toxicity were also analyzed. This work offers a new view on the design of PMS-activated catalysts.

Nanodiamond surface as a photoluminescent pH sensor

A systematic spectroscopic characterization of highly homogeneous water suspensions of ‘buckydiamonds’ comprising sp3 cubic nanodiamond (ND) core covered with disordered sp2 shell densely decorated with oxygen-containing groups demonstrates the excitation-wavelength-dependent photoluminescence (PL) given by at least four types of specific structures on the ND surface (hydroxyl, C=O containing ketones, carboxylic anhydrides, and carboxyl groups). PL properties of NDs suspensions possess concentration-dependent behavior revealing tendency of NDs to agglomerate. PL of NDs has been found to be strongly sensitive to pH of the environment in wide range of pH values, i.e. 2–11. We disclosed the mechanisms of pH sensitivity of the ‘buckydiamond’ and proved that it can serve as all-optical sensor of tiny pH variations suitable for further exploitation for pH sensing locally in the area where NDs have been delivered for any purpose, e.g. bioimaging or therapeutic needs.

Simultaneous removal of nitrogen and arsenite by heterotrophic nitrification and aerobic denitrification bacterium Hydrogenophaga sp. H7.

Nitrogen and arsenic contaminants often coexist in groundwater, and microbes show the potential for simultaneous removal of nitrogen and arsenic. Here, we reported that Hydrogenophaga sp. H7 was heterotrophic nitrification and aerobic denitrification (HNAD) and arsenite [As(III)] oxidation bacterium. The appearance of nitrogen removal and As(III) oxidation of Hydrogenophaga sp. H7 in liquid culture medium was studied. The effect of carbon source, C/N ratio, temperature, pH values, and shaking speeds were analyzed. The impact of strains H7 treatment with FeCl3 on nitrogen and As(III) in wastewater was assessed. The key pathways that participate in simultaneous nitrogen removal and As(III) oxidation was analyzed by genome and proteomic analysis. Strain H7 presented efficient capacities for simultaneous NH4 +-N, NO3 --N, or NO2 --N removal with As(III) oxidation during aerobic cultivation. Strikingly, the bacterial ability to remove nitrogen and oxidize As(III) has remained high across a wide range of pH values, and shaking speeds, exceeding that of the most commonly reported HNAD bacteria. Additionally, the previous HNAD strains exhibited a high denitrification efficiency, but a suboptimal concentration of nitrogen remained in the wastewater. Here, strain H7 combined with FeCl3 efficiently removed 96.14% of NH4 +-N, 99.08% of NO3 --N, and 94.68% of total nitrogen (TN), and it oxidized 100% of As(III), even at a low nitrogen concentration (35 mg/L). The residues in the wastewater still met the V of Surface Water Environmental Quality Standard of China after five continuous wastewater treatment cycles. Furthermore, genome and proteomic analyses led us to propose that the shortcut nitrification-denitrification pathway and As(III) oxidase AioBA are the key pathways that participate in simultaneous nitrogen removal and As(III) oxidation.

Crocodile defensin (CpoBD13) antifungal activity via pH-dependent phospholipid targeting and membrane disruption

Crocodilians are an order of ancient reptiles that thrive in pathogen-rich environments. The ability to inhabit these harsh environments is indicative of a resilient innate immune system. Defensins, a family of cysteine-rich cationic host defence peptides, are a major component of the innate immune systems of all plant and animal species, however crocodilian defensins are poorly characterised. We now show that the saltwater crocodile defensin CpoBD13 harbors potent antifungal activity that is mediated by a pH-dependent membrane-targeting action. CpoBD13 binds the phospholipid phosphatidic acid (PA) to form a large helical oligomeric complex, with specific histidine residues mediating PA binding. The utilisation of histidine residues for PA engagement allows CpoBD13 to exhibit differential activity at a range of environmental pH values, where CpoBD13 is optimally active in an acidic environment.

Comprehensive understanding of fluoroquinolone degradation via MPUV/PAA process: Radical chemistry, matrix effects, degradation pathways, and toxicity.

The wide occurrence of fluoroquinolones (FQs) in aquatic environments has aroused increasing concern about their potential adverse effects on human health. In this study, an emerging advanced oxidation process, i.e., the Medium-Pressure Ultraviolet/Peracetic Acid (MPUV/PAA) process, was used to degrade FQs (e.g., levofloxacin (LEV), norfloxacin, and ciprofloxacin). Compared with the MPUV process alone and the PAA process alone, the MPUV/PAA process significantly promoted degradation of FQs due to the considerable contribution of reactive radicals. Probe experiments revealed that PAA-specific organic radicals (e.g., CH3C(O)O• and CH3C(O)OO•) were the major radicals responsible for FQ elimination. Rapid degradation of FQs via the MPUV/PAA process was achieved within a wide range of pH values (5-9) by selecting LEV as the target compound, and higher pH values were more favorable for the reaction. The slight impacts of Cl- and CO32-/HCO3- on LEV removal were observed. The transformation products and pathways of LEV were identified, and nearly all of the transformation pathways occurred on the piperazine ring. Based on Quantitative Structure-Activity Relationship (QSAR) analysis, most of the products had lower toxicities than LEV. Overall, these findings improve our understanding and application of the MPUV/PAA process for degrading emerging contaminants in (waste)water treatment.

Correlation of Microplastic Size Distribution and Water Quality Parameters in the Upstream Brantas River

Microplastics are contaminants resulting from plastic fragmentation with a size <5 mm. The spread of microplastics threatens the imbalance of the environment and organisms in the waters. So it is necessary to know the abundance, size distribution, and correlation between microplastic abundance and water quality parameters. This study used a quantitative descriptive method with purposive sampling. The study parameters included total microplastic abundance, microplastic abundance based on size characteristics, type of microplastic polymer, water quality parameters, and correlation between microplastic abundance and water quality. Calculating the total abundance of microplastics obtained a value range of 3311.11 – 18111.11 particles/m3. The results of the microplastic size distribution got the highest abundance percentage value in the class with a size <50 µm, which was 84.39%. There were eight types of polymers identified, including Polyethylene (PE), Polyvinyl chloride (PVC), Polypropylene (PP), High-density polyethylene (HDPE), Low-density polyethylene (LDPE, Polyethylene terephthalate (PET), Polycarbonate (PC), and Nylon. Water quality measurements obtained temperature range of 17.37-26.63 °C, pH value range of 6.66-8.51, current velocity value range of 0.13-0.8 m/s, DO value range of 4, 32-6.103 ppm, BOD value range of 4.69-6.07 ppm and TSS value range 0.005-0.019 ppm. Correlation analysis using the Canonical Correlation Analysis (CCA) statistical method. The study showed that water quality parameters such as temperature, current velocity, and DO have a high score of 0.95, 0.83, and 0.8.

Functional and physicochemical properties of protein from giant squid (Dosidicus gigas) extracted using foam-aided pH-shift processing.

Jumbo squid (Dosidicus gigas) is a commercially valuable mollusk in Mexico; 80% of its body is edible. Despite the high protein content (∼18%) and low cholesterol content of this species, its high proteolytic activity (microbial and endogenous enzymes) induces protein degradation and consequent reduction in functional properties from a structural viewpoint. Gelation capacity (texture profile of the gels obtained), solubility, water holding capacity, foaming capacity, emulsification capacity, and emulsion stability were evaluated in protein concentrates obtained by foam-aided pH-shift processing: (A) myofibrillar protein extraction with distilled water and no pH-shifting; (B) alkaline solubilization and isoelectric precipitation; (C) acidic solubilization and isoelectric precipitation; and (D) process A and isoelectric precipitation. Process B showed superior gelation capacity, D had high emulsion stability across a wide range of pH values (4.0-8.0) and C lower plate counts of aerobic mesophilic. Therefore, all three alternative extraction processes showed techno-functional advantages. PRACTICAL APPLICATION: Jumbo squid is an abundant protein source in México, most of which is exported. Functional and physicochemical properties of muscle protein were improved by pH-shift processing. The recovered protein showed modifications of technological properties, using one of the methods described can lead to produce a protein extract with the most desirable attributes, such as foaming, emulsifying, or gelling capacities. The functional and physicochemical properties of protein from squid can be enhanced by selecting a certain pH-shift processing, depending on the desirable use. There is a broad perspective on the use of these protein extracts as ingredients or additives.

High capacity adsorption of oxytetracycline by lignin-based carbon with mesoporous structure: Adsorption behavior and mechanism

In this study, an adsorbent with mesoporous structure and PO/PO bonds is prepared by hydrothermal and phosphoric acid activation from industrial alkali lignin for the adsorption of oxytetracycline (OTC). The adsorption capacity is 598 mg/g, which is three times higher than that of the adsorbent with microporous structure. The rich mesoporous structure of the adsorbent provides adsorption channels and filling sites, and π-π attraction, cation-π interaction, hydrogen bonds, and electrostatic attraction provide adsorption forces at the adsorption sites. The removal rate of OTC exceeds 98 % over a wide range of pH values (3–10). It has high selectivity for competing cations in water, with higher than 86.7 % removal rate of OTC from medical wastewater. After 7 consecutive adsorption-desorption cycles, the removal rate of OTC remains as high as 91 %. This efficient removal rate and excellent reusability indicate the strong potential of the adsorbent for industrial applications. This study prepares a highly efficient, environmentally friendly antibiotic adsorbent that can not only efficiently remove antibiotics from water but also recycle industrial alkali lignin waste.

Missing Piece in Colloidal Stability─Morphological Factor of Hydrophobic Nanoparticles

Hydrophobic nanoparticles (NPs) in water were considered unstable because they lack the repulsive electrostatic interaction and steric effect to prevent aggregation. In this study, porous hydrophobic NPs of two star-shaped giant molecules, POSS-(R)8, were found to be stable in water and able to retain their kinetic stability in a wide range of temperatures, pH values, and ionic strengths. Unlike the solid hydrophobic NPs that aggregate even with the negative zeta potential (ζ) induced by surface-structured hydrogen-bonded (SHB) water, the porous morphology of POSS-(R)8 NPs reduces the entropically driven hydrophobic effect to prevent aggregation. With the porous morphology, the hydrophobic NPs are stable without the hydrophilic or charged surface functional groups and demonstrate good encapsulation capability. The morphological factor of colloids is thus one of the missing pieces in the theory of colloidal stability that extends our understanding of colloidal science.

Valorized soybean hulls as TEMPO-oxidized cellulose nanofibril and polyethylenimine composite hydrogels and their potential removal of water pollutants

Cellulose nanomaterial (CNM) and polyethylenimine (PEI) composites have attracted growing attention due to their multifunctional characteristics, which have been applied in different fields. In this work, soybean hulls were valorized into carboxyl cellulose nanofibrils (COOH-CNFs), and composited into hydrogels with PEI by combining them with cationic chelating and physical adsorption strategies. Cellulose nanofibrils (CNFs) were produced from soybean hulls prior to oxidation by a TEMPO mediated reaction to obtain COOH–CNFs; then drops of zinc chloride were added to 1.5% aqueous COOH–CNF dispersions, which were left for 24 h to form COOH-CNF hydrogels. Finally, the hydrogels were functionalized using different concentration of PEI solutions over a range of pH values. Elemental analysis results showed that 20% aq. PEI at pH 11.6 is the optimum condition to synthesize the COOH–CNF/PEI hydrogels. Additionally, the adsorption efficiency for the removal of anionic methyl blue dyes and Cu(II) ions from water was tested, reaching 82.6% and 69.8%, respectively, after 24 h. These results demonstrate the great potential of COOH–CNF/PEI hydrogels as adsorbent materials for water remediation.Graphical abstract

3D Viologen-based covalent organic framework for selective and efficient adsorption of ReO4−/TcO4−

Due to the long half-life and high environmental mobility, the selective and efficient capture of TcO4− from nuclear effluents is very important, but it is still very challenging. Herein, we design and synthesize a novel three-dimensional (3D) cationic covalent organic framework (TFAM-BDNP) via Zincke reaction for selective capture of TcO4−/ReO4−. TFAM-BDNP exhibits high adsorption capacity (998 mg g−1) and extremely fast exchange kinetic (60 s) for ReO4− (the non-radioactive alternative to TcO4−), attributing to the open 3D hydrophobic channels, abundant active sites, and high chemical stability. More importantly, TFAM-BDNP shows good adsorption performance for ReO4− in the presence of significant excess competing anions with a wide pH value range of 2 to 12. Under complex simulated Hanford flow sample, TFAM-BDNP has outstanding removal efficiency of ReO4−. The adsorption mechanism of ReO4− is mainly caused by anion exchange process. This study provides a novel adsorbent for efficient capture of TcO4−/ReO4− in complex environmental systems and exploits an effective strategy for broadening the types of 3D COFs.

Delineating the Effects of Molecular and Colloidal Interactions of Dissolved Organic Matter on Titania Photocatalysis.

In the face of significant challenges to practical applications of photocatalysis for water treatment, recent reports revealed a potential route to overcome a problem posed by dissolved organic matter (DOM). These studies showed that inhibition of photocatalytic processes by DOM is driven largely by competition for active surface sites on TiO2 or other catalysts, and controlling the type of DOM present in solution could significantly mitigate DOM fouling. Whether or not control of solution parameters could achieve the same preventative action is not known. Here, a series of DOM isolates, including humic acid (HA) and transphilic (TPI), hydrophobic (HPO), or colloidal fractions of organic matter from a membrane bioreactor mixed liquor supernatant, were tested for inhibitory activity under a range of pH values (3, 5, 7, and 9) and ionic compositions (NaCl, CaCl2, and Al2(SO4)3 with ionic strengths (IS) ranging from 0 to 3 M). The resulting TiO2-DOM agglomerates were monitored for size and ζ-potential. Inhibitory profiles were generated using para-chlorobenzoic acid (pCBA) as probe with varying concentrations of inhibitory DOM for each solution condition to discern the extent of surface-phase quenching of radicals. Manipulation of pH clearly impacted inhibition, and the effect varied by DOM type; for example, interference occurred at all pHs for HA, at neutral or basic pHs for TPI, and only at pH 7 for HPO. Particle sizes did not correlate with inhibitory action of DOM. Increases in ionic strength induced growth of TiO2 and TiO2-DOM agglomerates, but again, particle sizes did not correlate to inhibition by DOM. The changes to IS, regardless of ion type, were not affected by the presence of TPI or HPO. Since particle stability did not correlate directly with photocatalytic activity, we suggest that surface-based quenching reactions arise from site-specific adsorption rather than generalized particle destabilization and aggregation.

Isoflavone glucoside genistin, an inhibitor targeting Sortase A and Listeriolysin O, attenuates the virulence of Listeria monocytogenes in vivo and in vitro

As a common intracellular facultative anaerobic Gram-positive bacterium, Listeria monocytogenes (L. monocytogenes) exhibits strong resistance to extreme environments, such as low temperature and a wide range of pH values, causing contamination in food production and processing. Sortase A (SrtA) and listeriolysin O (LLO), two crucial virulence factors of L. monocytogenes, are widely recognized as potential targets for the development of anti-L. monocytogenes infection drugs. In this study, we found that genistin simultaneously inhibits the peptidase activity of SrtA and the hemolytic activity of LLO without affecting the growth of L. monocytogenes, alleviating concerns about developing resistance. Furthermore, we demonstrated that genistin reduces L. monocytogenes biofilm formation and invasion of human colorectal cancer (Caco‐2) cells. Subsequent mechanistic studies revealed that genistin inhibited LLO-mediated Caco-2 cell damage by blocking LLO oligomerization. Fluorescence quenching assay revealed the potential binding mode of SrtA and LLO to genistin. Genistin might bind to the active pocket of SrtA through residues Leu33, Asn29, and Met40, interacting with D1 domain of LLO involved in oligomerization and pore formation through residues Asn259. Studies in infection models revealed that genistin reduces mortality and pathological damage in mice infected with L. monocytogenes. These results indicate that genistin is a promising anti-virulence agent that could be considered an alternative candidate for the treatment of L. monocytogenes infection.

Solution pH Effect on Drain-Gate Characteristics of SOI FET Biosensor

Nanowire or nanobelt sensors based on silicon-on-insulator field-effect transistors (SOI-FETs) are one of the leading directions of label-free biosensors. An essential issue in this device construction type is obtaining reproducible results from electrochemical measurements. It is affected by many factors, including the measuring solution and the design parameters of the sensor. The biosensor surface should be charged minimally for the highest sensitivity and maximum effect from interaction with other charged molecules. Therefore, the pH value should be chosen so that the surface has a minimum charge. Here, we studied the SOI-FET sensor containing 12 nanobelt elements concatenated on a single substrate. Two types of sensing elements of similar design and different widths (0.2 or 3 μm) were located in the chips. The drain-gate measurements of wires with a width of 3 µm are sufficiently reproducible for the entire chip to obtain measurement statistics in air and deionized water. For the pH values from 3 to 12, we found significant changes in source-drain characteristics of nanobelts, which reach the plateau at pH values of 7 and higher. High pH sensitivity (ca. 1500 and 970 mV/pH) was observed in sensors of 3 μm and 0.2 μm in width in the range of pH values from 3 to 7. We found a higher “on” current to “off” current ratio for wide wires. At all studied pH values, Ion/Ioff was up to 4600 and 30,800 for 0.2 and 3 μm wires, respectively. In the scheme on the source-drain current measurements at fixed gate voltages, the highest sensitivity to the pH changes reaches a gate voltage of 13 and 19 V for 0.2 μm and 3 μm sensors, respectively. In summary, the most suitable is 3 μm nanobelt sensing elements for the reliable analysis of biomolecules and measurements at pH over 7.

Biophysical evaluation of the oligomerization and conformational properties of the N-terminal domain of TDP-43

TDP-43 is an RNA-binding protein that presents four domains comprising an N-terminal region, two RNA recognition motifs and a C-terminal region. The N-terminal domain (NTD) has a relevant role in the oligomerization and splicing activity of TDP-43. In this work, we have expressed, purified and biophysically characterized the region that includes residues 1 to 102 that contains the nuclear localization signal (residues 80–102, NLS). Furthermore, we have evaluated the oligomerization equilibrium for this protein fragment. Also, we have determined changes in the tertiary structure and its stability in a broad range of pH values by means of different spectroscopic methods. Additionally, we compared this fragment with the one that lacks the NLS employing experimental and computational methods. Finally, we evaluated the motion of dimeric forms to get insights into the conformational flexibility of this TDP-43 module in an oligomeric state. Our results suggest that this domain has a conformational plasticity in the vicinity of the single tryptophan of this domain (Trp68), which is enhanced by the presence of the nuclear localization signal. All these results help to understand the molecular features of the NTD of TDP-43.

The characteristic of East Kalimantan’s low-rank coal as an adsorbent for Methylene Blue (MB) dye removal from simulated textile wastewater

As the interest in developing and applying low-cost adsorbents is growing, the purpose of this paper is to introduce East Kalimantan’s low-rank coal as an adsorbent that is abundant in nature but underutilized. This adsorbent was used in a batch adsorption process to remove Methylene Blue (MB) from simulated textile wastewater. The study was conducted at a range of pH values (from 3 to 13) using a variety of low-rank coal adsorbents (60, 80, 100, 120, 140, and 160 mg). Approximately 100 mg/L of MB was added to 100 mL of simulated textile wastewater over 60 minutes using a shaker set to 150 rpm. The pH value and the amount of adsorbent used have a significant effect on removing MB dye. The pH results indicated that the removal of MB dye is relatively constant between pH 3 and 11. However, the removal rate increased when the pH was increased to 12—increased the pH to 13, which resulted in a significant decrease in MB dye removal. Meanwhile, as the adsorbent dosage increased from 60 to 100 mg at pH 12, the removal of MB dye increased and then decreased. At pH 12 and adsorbent dosage of 100 mg, the maximum removal of MB dye was 99.40 %. Thus, East Kalimantan’s low-rank coal is an intriguing alternative for removing MB dye from simulated textile wastewater.

A Novel, Highly Potent NADPH-Dependent Cytochrome P450 Reductase from Waste Liza klunzingeri Liver.

The use of marine enzymes as catalysts for biotechnological applications is a topical subject. Marine enzymes usually display better operational properties than their animal, plant or bacterial counterparts, enlarging the range of possible biotechnological applications. Due to the fact that cytochrome P450 enzymes can degrade many different toxic environmental compounds, these enzymes have emerged as valuable tools in bioremediation processes. The present work describes the isolation, purification and biochemical characterization of a liver NADPH-dependent cytochrome P450 reductase (CPR) from the marine fish Liza klunzingeri (LkCPR). Experimental results revealed that LkCPR is a monomer of approximately 75 kDa that is active in a wide range of pH values (6-9) and temperatures (40-60 °C), showing the highest catalytic activity at pH 8 and 50 °C. The activation energy of the enzyme reaction was 16.3 kcal mol-1 K-1. The KM values for cytochrome C and NADPH were 8.83 μM and 7.26 μM, and the kcat values were 206.79 s-1 and 202.93 s-1, respectively. LkCPR displayed a specific activity versus cytochrome C of 402.07 µmol min-1 mg1, the highest activity value described for a CPR up to date (3.2-4.7 times higher than the most active reported CPRs) and showed the highest thermostability described for a CPR. Taking into account all these remarkable catalytic features, LkCPR offers great potential to be used as a suitable biocatalyst.