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Functional amyloids, beneficial to the organism producing them, are found throughout life, from bacteria to humans. While disease‐related amyloids form by uncontrolled aggregation, the fibrillation of functional amyloid is regulated by complex cellular machinery and optimized sequences, including so‐called gatekeeper residues such as Asp. However, the molecular basis for this regulation remains unclear. Here we investigate how the introduction of additional gatekeeper residues affects fibril formation and stability in the functional amyloid CsgA from E. coli. Step‐wise introduction of additional Asp gatekeepers gradually eliminated fibrillation unless preformed fibrils were added, illustrating that gatekeepers mainly affect nucleus formation. Once formed, the mutant CsgA fibrils were just as stable as wild‐type CsgA. HSQC NMR spectra confirmed that CsgA is intrinsically disordered, and that the introduction of gatekeeper residues does not alter this ensemble. NMR‐based Dark‐state Exchange Saturation Transfer (DEST) experiments on the different CsgA variants, however, show a decrease in transient interactions between monomeric states and the fibrils, highlighting a critical role for these interactions in the fibrillation process. We conclude that gatekeeper residues affect fibrillation kinetics without compromising structural integrity, making them useful and selective modulators of fibril properties. [ABSTRACT FROM AUTHOR]

Background: Identification of auditory processing disorders is achieved using questionnaires along with linguistic, non-linguistic, and auditory processing tests. Notably, the questionnaires "Children's Auditory Performance Scale" (CHAPS) and "Auditory Processing Domain Questionnaire" (APDQ) are widely recognized and used. The current study investigated the psychometric properties of the CHAPS and APDQ in Greek Cypriot children. Methods: The CHAPS and APDQ questionnaires were completed by parents of 40 Greek Cypriot children, 16 typically developing (TD) children, and 24 children with a history of Speech Sound Disorders (SSDs). Results: There were significant differences between the two groups on both questionnaires. Cronbach's alpha was calculated at α = 0.922 for the CHAPS total score and α = 0.926 for the APDQ total score. The Receiver Operating Curve (ROC) analysis provided a cut-off point equal to −0.30 (AUC 0.849, p < 0.001) for CHAPS and a cut-off point equal to 90.00 (AUC 0.820, p < 0.001) for APDQ. Significant positive Spearman ρ correlations were observed between the CHAPS and APDQ (ρ = 0.639, p = 0.001). Conclusions: The CHAPS and APDQ can identify distinct auditory processing characteristics between in children with SSDs and TD children. [ABSTRACT FROM AUTHOR]

Background: Identification of auditory processing disorders is achieved using questionnaires along with linguistic, non-linguistic, and auditory processing tests. Notably, the questionnaires “Children’s Auditory Performance Scale” (CHAPS) and “Auditory Processing Domain Questionnaire” (APDQ) are widely recognized and used. The current study investigated the psychometric properties of the CHAPS and APDQ in Greek Cypriot children. Methods: The CHAPS and APDQ questionnaires were completed by parents of 40 Greek Cypriot children, 16 typically developing (TD) children, and 24 children with a history of Speech Sound Disorders (SSDs). Results: There were significant differences between the two groups on both questionnaires. Cronbach’s alpha was calculated at α = 0.922 for the CHAPS total score and α = 0.926 for the APDQ total score. The Receiver Operating Curve (ROC) analysis provided a cut-off point equal to −0.30 (AUC 0.849, p < 0.001) for CHAPS and a cut-off point equal to 90.00 (AUC 0.820, p < 0.001) for APDQ. Significant positive Spearman ρ correlations were observed between the CHAPS and APDQ (ρ = 0.639, p = 0.001). Conclusions: The CHAPS and APDQ can identify distinct auditory processing characteristics between in children with SSDs and TD children.

Aquaporin (AQP) is a water channel protein from the family of transmembrane proteins which facilitates the movement of water across the cell membrane. It is ubiquitous in nature, however the understanding of the water transport mechanism, especially for AQPs in microbes adapted to low temperatures, remains limited. AQP also has been recognized for its ability to be used for water filtration, but knowledge of the biochemical features necessary for its potential applications in industrial processes has been lacking. Therefore, this research was conducted to express, extract, solubilize, purify, and study the functional adaptations of the aquaporin Z family from Pseudomonas sp. AMS3 via molecular approaches. In this study, AqpZ1 AMS3 was successfully subcloned and expressed in E. coli BL21 (DE3) as a recombinant protein. The AqpZ1 AMS3 gene was expressed under optimized conditions and the best optimized condition for the AQP was in 0.5 mM IPTG incubated at 25°C for 20 h induction time. A zwitterionic mild detergent [(3‐cholamidopropyl) dimethylammonio]‐1‐propanesulfonate was the suitable surfactant for the protein solubilization. The protein was then purified via affinity chromatography. Liposome and proteoliposome was reconstituted to determine the particle size using dynamic light scattering. This information obtained from this psychrophilic AQP identified provides new insights into the structural adaptation of this protein at low temperatures and could be useful for low temperature application and molecular engineering purposes in the future. [ABSTRACT FROM AUTHOR]

Amberlite has been shown to be an appropriate material for the adsorption of organic contaminants from aqueous solutions. In addition, Amberlite XAD-2 has been successfully used, as an alternative to Bio-Beads, to remove Triton X-100 from protein solutions, such as from samples of solubilized membrane proteins. However, Amberlite has not been tested as an adsorbent when a mixture of detergents is necessary to solubilize and refold a target protein. Here the authors show that Amberlite XAD-4 can be appropriately used to aid the purification process of proteins solubilized from inclusion bodies with the ternary detergent system consisting of Sarkosyl, Triton X-100 and CHAPS.

Functional amyloids, beneficial to the organism producing them, are found throughout life, from bacteria to humans. While disease-related amyloids form by uncontrolled aggregation, the fibrillation of functional amyloid is regulated by complex cellular machinery and optimized sequences, including so-called gatekeeper residues such as Asp. However, the molecular basis for this regulation remains unclear. Here we investigate how the introduction of additional gatekeeper residues affects fibril formation and stability in the functional amyloid CsgA from E. coli. Step-wise introduction of additional Asp gatekeepers gradually eliminated fibrillation unless preformed fibrils were added, illustrating that gatekeepers mainly affect nucleus formation. Once formed, the mutant CsgA fibrils were just as stable as wild-type CsgA. HSQC NMR spectra confirmed that CsgA is intrinsically disordered, and that the introduction of gatekeeper residues does not alter this ensemble. NMR-based Dark-state Exchange Saturation Transfer (DEST) experiments on the different CsgA variants, however, show a decrease in transient interactions between monomeric states and the fibrils, highlighting a critical role for these interactions in the fibrillation process. We conclude that gatekeeper residues affect fibrillation kinetics without compromising structural integrity, making them useful and selective modulators of fibril properties., (© 2024 The Author(s). Protein Science published by Wiley Periodicals LLC on behalf of The Protein Society.)

The utility of CHAPS-PC, a detergent combination for solubilizing membrane proteins, was investigated as a substitute to digitonin solution for extracting rhodopsin in the measurement of spectral sensitivity in squid. Microvilli of the photoreceptor outer segments were collected and purified from the retinas of three species, Uroteuthis edulis, Todarodes pacificus, and Heterololigo bleekeri, using sucrose density-gradient centrifugation. The difference in the absorption maximum (λmax) of rhodopsin between extraction with CHAPS-PC or with digitonin was 0–3 nm for all species. The λmax values of the three squid species were 488–490, 478–480, and 488–491 nm, respectively, which aligns well with values reported in previous studies. CHAPS and PC are less expensive than digitonin, which is advantageous when conducting repeated experiments. We hope that the present procedure for the extraction of visual pigments offers an improved fisheries technology that will be used to better understand the ecology of diverse squid species. [ABSTRACT FROM AUTHOR]

The interaction between Hen Egg White Lysozyme (HEWL) and 3-[(3-cholamidopropyl) dimethyl-ammonio]-1-propanesulphonate (CHAPS) was examined using biophysical techniques (spectrofluorometric, circular dichroism, and dynamic light scattering) at pH 9.0. The results obtained from multi-techniques showed that CHAPS interact with the HEWL strongly and affects protein conformations. The far-UV CD results suggest that lower as well as higher (1.0–15.0 mM) concentrations of CHAPS are inducing α-helical structure in HEWL. The near-UV CD and fluorescence data indicated that the tertiary structure of HEWL is alter in the presence of CHAPS. The ANS dye binding suggest that the exposure of HEWL tertiary structure is dependent on CHAPS concentration. As the concentrations of CHAPS is increasing the exposure of HEWL tertiary structure is also increasing and maximum exposure was found at 15.0 mM of CHAPS concentrations. The hydrodynamic radii of HEWL is also increase in the presence of sub-micellar and micellar concentrations of CHAPS because the tertiary structure of HEWL is disrupted. Overall, the results suggest that CHAPS is inducing secondary structure and disrupting tertiary structure of HEWL. This study provides detailed interaction of CHAPS with HEWL at the molecular level.

BACKGROUND 3‐[(3‐Cholamidopropyl)dimethylammonio]‐1‐propanesulfonate (CHAPS) is a zwitterionic detergent commonly utilized in protein biochemistry‐based applications. This study demonstrates for the first time the successful phase separation of CHAPS via salt addition. Elucidation of consolute solution temperature behavior and determination of binodal curve and tie‐line length (TLL) enabled the subsequent development of CHAPS‐based phase separation systems. The systems were then evaluated using a low‐molecular‐weight dye, Coomassie Brilliant Blue (CBB), and integral membrane protein, cytochrome P450 (CYP) 2C19. RESULTS: The anionic identity of salts was found to be critical, with sulfate and phosphate salts being successful in inducing phase separation of CHAPS at 4 °C. CHAPS and (NH4)2SO4 mixtures were later found to have an upper consolute solution temperature (UCST). Binodal data were collected and fitted to an equation to allow determination of the minimum amount of CHAPS and (NH4)2SO4 required for the formation of phase separation systems. In CHAPS/(NH4)2SO4 systems, CBB was found to partition extensively to the micelle‐rich phase (MRP) with an extraction yield of 83 ± 0.32%, while CYP 2C19 was successfully recovered with an extraction yield of 46 ± 7.58%. CONCLUSION: Phase separation of CHAPS achieved at low temperature via sulfate salt addition can be exploited for the extraction of hydrophobic molecules. The outcomes of this study propound the scope for application of CHAPS as a component of phase separation systems. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Although pulmonary diseases account for a large number of deaths in the world, most have no treatment other than transplantation. New therapeutic methods for lung treatment include lung tissue engineering and regenerative medicine. Lung decellularization has been used to produce an appropriate scaffold for recellularization and implantation. We investigated 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) with sodium dodecyl sulfate (SDS) and Triton X-100 detergents for effecting rat lung decellularization. We evaluated using conventional histology, immunofluorescence staining and SEM methods for removing nuclear material while leaving intact extracellular matrix proteins and three-dimensional architecture. We investigated different concentrations of CHAPS, SDS and Triton X-100 for different periods. We found that 2 mM CHAPS + 0/1% SDS for 48 h was the best among the treatments investigated. Our method can be used to produce an appropriate scaffold for recellularization by stem cells and for investigations ex vivo and in vivo. [ABSTRACT FROM AUTHOR]

Background: Current esophageal treatment is associated with significant morbidity. The gold standard therapeutic strategies are stomach interposition or autografts derived from the jejunum and colon. However, severe adverse reactions, such as esophageal leakage, stenosis and infection, accompany the above treatments, which, most times, are life threating. The aim of this study was the optimization of a decellularization protocol in order to develop a proper esophageal tissue engineered construct. Methods: Rat esophagi were obtained from animals and were decellularized. The decellularization process involved the use of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) buffers for 6 h each, followed by incubation in a serum medium. The whole process involved two decellularization cycles. Then, a histological analysis was performed. In addition, the amounts of collagen, sulphated glycosaminoglycans and DNA content were quantified. Results: The histological analysis revealed that only the first decellularization cycle was enough to produce a cellular and nuclei free esophageal scaffold with a proper extracellular matrix orientation. These results were further confirmed by biochemical quantification. Conclusions: Based on the above results, the current decellularization protocol can be applied successfully in order to produce an esophageal tissue engineered construct. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Solvent Paramagnetic Relaxation Enhancement has been introduced to study the detailed aggregation mode of CHAPS. • The core and surface of the micelle are formed mainly by the head, and tail of CHAPS, respectively. • The micelle in M2 state is mostly like to be a double layer structure with relatively tight but still messy aggregation Abstract CHAPS is a typical zwitterionic detergent widely used in protein purification. It has two peculiar aggregation states, whose aggregation patterns are still controversial and uncertain. In this paper, we analyzed the aggregation pattern of CHAPS by 1H solvent Paramagnetic Relaxation Enhancement (sPRE) experiment. It was found that the 1H sPREs of head groups of CHAPS are much smaller than those of the tail groups, and all of them become smaller simultaneously when the concentration of CHAPS is above CMC2. In addition, the sPREs of those protons in the steroid ring were found to be very similar to each other in both micellar states (M1 and M2). These results indicated that the micellar core of CHAPS is mainly formed by its steroid head which aggregate disorderly. On the other hand, a transition from single to double layer micelle is most likely to happen when the concentration of CHAPS is above CMC2. The micelle in M2 state is formed by the aggregation of the partially disordered primary ones as well. Furthermore, the STD (Saturation Transfer Difference) experiment showed that the apparent coherence transfer rates between water and those OH near protons at the steroid head are slower in M2 state, revealing that the CHAPS aggregate loosely in M1 state, but more tightly in M2 state, which may be driven by the increased hydrophobic interactions between the steroid groups of nearby CHAPS molecules, as well as the hydrogen bond between OH in the hydrophobic side and SO 3 −1, CO, or HN in the hydrophilic side of different molecules, which consequently extrude the water and stabilize the micelle. [ABSTRACT FROM AUTHOR]

Solubilization of membrane proteins by amphiphilic detergents represents a crucial step in studies of membrane proteins in which proteins and lipids in natural membranes are dissociated giving rise to mixed clusters of proteins, lipids and detergents in the aqueous dispersion. Although solubilization is a popular method, physicochemical principles underlying solubilization are not well understood. In this work, we monitored solubilization of the bovine hippocampal serotonin 1A receptor, a representative member of the GPCR family, using membrane dipole potential measured by a dual fluorescence ratiometric approach with a potential-sensitive fluorophore. Our results show that membrane dipole potential is a good indicator of solubilization and reflects the change in dipolar environment upon solubilization due to dipolar reorganization associated with solubilization. To the best of our knowledge, these results constitute the first report linking membrane dipole potential with solubilization. We envision that these results are potentially useful in providing a molecular mechanism for membrane protein solubilization. [ABSTRACT FROM AUTHOR]

Background: Current esophageal treatment is associated with significant morbidity. The gold standard therapeutic strategies are stomach interposition or autografts derived from the jejunum and colon. However, severe adverse reactions, such as esophageal leakage, stenosis and infection, accompany the above treatments, which, most times, are life threating. The aim of this study was the optimization of a decellularization protocol in order to develop a proper esophageal tissue engineered construct. Methods: Rat esophagi were obtained from animals and were decellularized. The decellularization process involved the use of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) buffers for 6 h each, followed by incubation in a serum medium. The whole process involved two decellularization cycles. Then, a histological analysis was performed. In addition, the amounts of collagen, sulphated glycosaminoglycans and DNA content were quantified. Results: The histological analysis revealed that only the first decellularization cycle was enough to produce a cellular and nuclei free esophageal scaffold with a proper extracellular matrix orientation. These results were further confirmed by biochemical quantification. Conclusions: Based on the above results, the current decellularization protocol can be applied successfully in order to produce an esophageal tissue engineered construct.

Ferritin naturally has a shell-like architecture with inner/outer surfaces, which can be applied as a nanovehicle of biologically active molecules. Herein, a CHAPS-involved scheme was arranged to fabricate the ferritin-agaro oligosaccharide-epigallocatechin gallate (EGCG) nanoparticle (FAE) partitioned by the ferritin shell. A concentration (10 mM) of CHAPS expanded the channel size of phytoferritin by remarkably improving the rate of iron release and facilitated the encapsulation of EGCG without disassembling the ferritin. The encapsulating ratio of EGCG reached (10.8 ± 0.13) %, about 17.2 EGCG per ferritin cage. Meanwhile, agaro oligosaccharide could attach on the ferritin outer surface with a stoichiometric number of 12.1 ± 0.31 (agaro oligosaccharide/ferritin) and a binding constant of (3.25 ± 0.23) × 105 M−1. The diameter of FAE was maintained at ∼12 nm, and the hydrodynamic radius (R H) was 7.61 nm, proving that the agaro oligosaccharide attachment and the encapsulation of EGCG retained the ferritin morphology. In addition, the CHAPS acted in alleviating the association effect of the ferritin when forming FAE. Moreover, the agaro oligosaccharide as the second layer attaching on the ferritin surface significantly improved the EGCG stability in FAE towards heating treatment and controlled the release of EGCG in a more sustained manner. This study highlights the role of CHAPS and fabricates a triple-layer nanoparticle in a simple way, which expands the fabrication method of oligosaccharide-protein-polyphenol polymers and is conducive to the stability of food bioactive molecules. [Display omitted] • CHAPS could induce the expansion of the size of the ferritin channels. • CHAPS enabled the formation of ferritin-AO-EGCG triple-layer nanoparticle (FAE). • CHAPS alleviated association effect of ferritin and promoted EGCG encapsulation. • AO attaching on the ferritin improved the thermal stability of EGCG. • AO attaching on the ferritin sustained the controlled release of EGCG. [ABSTRACT FROM AUTHOR]

Human S100A9 (Calgranulin B) is a Ca 2 + -binding protein, from the S100 family, that often presents as a homodimer in myeloid cells. It becomes an important mediator during inflammation once calcium binds to its EF-hand motifs. Human RAGE protein (receptor for advanced glycation end products) is one of the target-proteins. RAGE binds to a hydrophobic surface on S100A9. Interactions between these proteins trigger signal transduction cascades, promoting cell growth, proliferation, and tumorigenesis. Here, we present the solution structure of mutant S100A9 (C3S) homodimer, determined by multi-dimensional NMR experiments. We further characterize the solution interactions between mS100A9 and the RAGE V domain via NMR spectroscopy. CHAPS is a zwitterionic and non-denaturing molecule widely used for protein solubilizing and stabilization. We found out that CHAPS and RAGE V domain would interact with mS100A9 by using 1 H- 15 N HSQC NMR titrations. Therefore, using the HADDOCK program, we superimpose two binary complex models mS100A9-RAGE V domain and mS100A9-CHAPS and demonstrate that CHAPS molecules could play a crucial role in blocking the interaction between mS100A9 and the RAGE V domain. WST-1 assay results also support the conclusion that CHAPS inhibits the bioactivity of mS100A9. This report will help to inform new drug development against cell proliferation. [ABSTRACT FROM AUTHOR]

Discussion of the Court of Appeal’s decision in the Tidal Energy v Bank of Scotland case relating to the question of whether a customer had been taken to contract on the basis of standard banking practice with regard to the use of unique identifiers in a CHAPS transaction. Assesses the knowledge of the customer as to this issue and the importance of commercial common sense. [ABSTRACT FROM AUTHOR]

Amberlite has been shown to be an appropriate material for the adsorption of organic contaminants from aqueous solutions. In addition, Amberlite XAD-2 has been successfully used, as an alternative to Bio-Beads, to remove Triton X-100 from protein solutions, such as from samples of solubilized membrane proteins. However, Amberlite has not been tested as an adsorbent when a mixture of detergents is necessary to solubilize and refold a target protein. Here the authors show that Amberlite XAD-4 can be appropriately used to aid the purification process of proteins solubilized from inclusion bodies with the ternary detergent system consisting of Sarkosyl, Triton X-100 and CHAPS.

Use of Cry1Ac δ-endotoxin of Bacillus thuringiensis (Bt) has revolutionized crop protection especially in cotton. Large quantities of Cry1Ac protein are needed for several basic studies. Heterologous expression in E. coli facilitates production of large quantities of recombinant Cry1Ac protein. However, earlier studies reported that E. coli expressed recombinant protein leads to large variations in LC50 values. Here we report a method of active Cry1Ac δ-endotoxin purification that is simple, robust and exhibits higher toxicity with consistent results in insect bioassays. In this protocol proteolysis separates completely folded Cry1Ac δ-endotoxin molecules (active toxin) from nonnative protein folding forms and other host proteins, followed by extraction of active Cry1Ac toxin by micro filtration. Insect bioassay of purified Cry1Ac toxin with Helicoverpa armigera showed 125 times enhanced toxicity (LC50 40 pg/cm2) as compared to the earlier reports (LC50 ng/cm2) 4.5 to 3500 ng/cm2. These results provide a new prospective in determination of baseline susceptibility, monitoring resistance development and utilization of its potential. [ABSTRACT FROM AUTHOR]

Human and porcine cysticercosis is caused by the larval stage of the flatworm Taenia solium (Cestoda). The protein extracts of T. solium cysts are complex mixtures including cyst's and host proteins. Little is known about the influence of using different detergents in the efficiency of solubilization–extraction of these proteins, including relevant antigens. Here, we describe the use of CHAPS, ASB-14 and Triton X-100, alone or in combination in the extraction buffers, as a strategy to notably increase the recovery of proteins that are usually left aside in insoluble fractions of cysts. Using buffer with CHAPS alone, 315 protein spots were detected through 2D-PAGE. A total of 255 and 258 spots were detected using buffers with Triton X-100 or ASB-14, respectively. More protein spots were detected when detergents were combined, i.e., 2% CHAPS, 1% Triton X-100 and 1% ASB-14 allowed detection of up to 368 spots. Our results indicated that insoluble fractions of T. solium cysts were rich in antigens, including several glycoproteins that were sensitive to metaperiodate treatment. Host proteins, a common component in protein extracts of cysts, were present in larger amounts in soluble than insoluble fractions of cysts proteins. Finally, antigens present in the insoluble fraction were more appropriate as a source of antigens for diagnostic procedures. [ABSTRACT FROM AUTHOR]

Neurotensin receptor type 1 (NTS1) is a G protein‐coupled receptor (GPCR) that affects cellular responses by initiating a cascade of interactions through G proteins. The kinetic details for these interactions are not well‐known. Here, NTS1‐nanodisc‐Gαs and Gαi1 interactions were studied. The binding affinities of Gαi1 and Gαs to NTS1 were directly measured by surface plasmon resonance (SPR) and determined to be 15 ± 6 nM and 31 ± 18 nM, respectively. This SPR configuration permits the kinetics of early events in signalling pathways to be explored and can be used to initiate descriptions of the GPCR interactome.Little is known of the kinetics of interactions between GPCRs and their signalling partners. NTS1 binds Gαi1 and Gαs with affinities of 15±6nM and 31±18nM (SE), respectively. This SPR assay may be applicable to multiple partners in the signalling cascade. We provide the first direct evidence for GPCR‐G protein coupling in nanodiscs. [ABSTRACT FROM AUTHOR]

Abstract: Kinetics of cerium(IV) oxidation of aliphatic alcohols: ethanol, propanol, propan-2-ol, 1-butanol and 2-butanol were studied at 30°C in the presence and absence of surfactants in acidic medium. The reaction was studied under pseudo-first-order conditions, [alcohol]T ≫[Ce(IV)]T. Ir(III)-salt used as catalyst had a significant effect on reaction rate. Cationic surfactant CPC (N-cetylpyridinium chloride) inhibits the reaction rate but zwitterionic surfactant CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) catalyzes the oxidation reaction significantly. CMC value of CHAPS was determined by a spectrofluorometer. The reaction rate increased with increase in the acid concentration of the medium. NMR and FTIR spectra confirmed the oxidized products. The aggregation of surfactants in the reaction condition was studied through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Dynamic light scattering (DLS) was used to characterize the shape changes of the aggregates. The variations of the reaction rates for the different alcohols in the presence of surfactants and metal ion catalyst are discussed qualitatively in terms of Berezin's model, nature of surfactants, and charge of surfactants. Ir(III) in association with CHAPS micellar catalyst exhibited ~500–2000fold rate enhancements compared to the uncatalyzed reaction path. [Copyright &y& Elsevier]

Highlights: [•] BaxΔC interacts with CHAPS directly, but relatively weakly. [•] BaxΔC interacts with BaxBH3 or BimBH3 peptide directly, and relatively strongly. [•] Binding with BaxBH3 or BimBH3 resulted in substantial spectral changes to BaxΔC. [•] BaxBH3 or BimBH3 bounded BaxΔC is monomeric, but dimerizes when CHAPS is presented. [Copyright &y& Elsevier]

Abstract: Anionic biological surfactant sodium cholate (NaC) and the zwitterionic nontoxic surfactant CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) having common steroidal skeleton have not been studied in a comparative level to explore their amphiphilic behaviors separately and in mixed states. Their adsorption at the interface in relation to self-association in solution has been examined in both pure and mixed states with reference to detailed thermodynamic analysis of their surface chemical and solution behaviors. Their head group differences are responsible for the differences in their properties viz. critical micelle concentration (CMC), aggregation number (N), hydrodynamic diameter, Gibbs surface excess (Γ max), minimum head group area (A min), mixed micelle composition and their mixing ideality/nonideality. Although the CMC values found from tensiometry and isothermal titration calorimetry (ITC) are in good agreement, the standard enthalpy of micellization ( ) found from ITC at different temperatures are different from that evaluated by the van't Hoff method. This is because van't Hoff rationale is a differential method which estimates the enthalpy of the monomer ↔ micelle equilibrium process whereas calorimetry is an integral process that evaluates all probable/possible processes in addition to monomer to micelle conversion. Results are analyzed, compared and discussed in the light of physicochemical parameters of pure NaC and CHAPS and their mixtures. These fundamental findings are considered prospective in pharmaceutical, biochemical and biomedical applications of the studied bio-friendly amphiphiles. [Copyright &y& Elsevier]

Numerous studies have demonstrated that neighborhood context contributes to variations in morbidity and mortality. This body of work includes a burgeoning literature that links adverse neighborhood characteristics (e.g., neighborhood poverty and perceptions of disorder and dangerousness) with poorer sleep outcomes. During the COVID-19 pandemic, many neighborhoods exhibited socioeconomic downturns and escalations in crime and violence. The question is the extent to which these changes in neighborhood conditions have impacted the sleep quality of residents. In this paper, we use original survey data from the 2021 Crime, Health, and Politics Survey (CHAPS), a national probability sample of adults living in the U.S., to formally test whether changes in perceptions of neighborhood dangerousness during the pandemic are associated with sleep quality during the same period. Regression analyses show that while reports of a neighborhood becoming safer during the pandemic are associated with better sleep quality, reports of a neighborhood becoming more dangerous are associated with worse sleep quality. Mediation analyses also indicate that the association between increased neighborhood dangerousness and poorer sleep quality is partially explained by a concurrent deterioration in diet quality, but not increases in alcohol or cigarette consumption. We conclude with a discussion of the implications of our findings for research and policy on neighborhood context and sleep. [ABSTRACT FROM AUTHOR]

Myelin sheath is a lipid-rich membrane, consisting of 70% lipid and 30% proteins, that is involved in physiological and pathological processes. For this reason its protein composition has been often investigated, principally by two-dimensional electrophoresis; however, the consistent lipid content makes it difficult to obtain good proteins separation. To improve the resolution of myelin proteins in a denaturing monodimensional gel electrophoresis, we examined several mixtures for the denaturation of the sample, utilizing different detergents and reducing agents. The definition of the protein pattern was analyzed by both “Blue Silver” Coomassie staining and Western Blot analysis against myelin basic protein, one of the most represented myelin proteins. The best resolution is observed when the sample was incubated with a mixture containing 1.25% dithiothreitol, 4Murea, and 1% dodecyl maltoside or 1 % 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate, prior to addition of denaturing agents. In conclusion, this work describes a novel method to improve the separation of myelin proteins in a monodimensional gel electrophoresis. It may be also useful for investigating other lipid-rich samples. [ABSTRACT FROM AUTHOR]

Abstract: One unique feature in cyanoprokaryotes, rhodophytes, and cryptophytes is the presence of phycobilin pigments-these water soluble pigments can absorb red, orange, yellow, and green light enhancing the spectral range available for cellular conversion to chemical energy. The presence of phycobilin pigment complexes can be detected using fluorescence, or absorbance measures. Efficient detection of these compounds is essential for use in calibrating absorbance in remote sensing or in physiological studies. The standard procedure for phycobilin analysis involves sonication, extraction in buffer potentially coupled with additional digestion steps using enzymes, repeated freeze and thawing cycles, followed by filtration, and spectrophotometric analyses. An alternative method, using asolectin-CHAPS ((3-[(3-cholamidopropyl)dimethylammonio]propanesulfonic acid – AC)) solution for extraction, and three cycles of freeze/thawing/sonication, was compared to the phosphate buffer (PB) standard procedure. Cultures of both coccoid and filamentous cyanoprokaryota had improved extraction efficiency (38–80%) using AC. After two complete extractions, no pigment was detectable in AC and near baseline fluorescence was observed in the cell pellet, whereas the PB extraction method removed <90% of the phycobilins after two extractions. Phycocyanin concentration measured by AC extraction was better correlated to lipophilic pigment concentration than using phosphate buffer extraction. AC buffered to pH 6.7 was more effective than AC 3.75. One potential source of experimental error was determined to be the use of a baseline correction for the extraction buffer, not the sample. [Copyright &y& Elsevier]

True lipolytic activity is observed in different subcellular fractions of germinating sunflower seedlings (Helianthus annuus L.) in delipidated oleosomes and microsomes. Triacylglycerol lipase (EC. 3.1.1.3) catalyses the first catabolic step of lipolysis. To our knowledge, this plant lipase has not yet been identified. Our aim was to develop a method to collect the lipase for further studies. An immunological method was used to capture sunflower seedling lipase from oleosomes and microsomes. This method uses an immunoaffinity column prepared with polyclonal antibodies (anti-P-61) directed against oleosomal activity. Our results verify that we have successfully adapted a purification procedure of plant lipase using anti-P-61. Since the eluted lipolytic activity is distributed among diverse proteic peaks, we changed the elution procedure: the introduction of CHAPS, a zwitterionic detergent, allowed us to recover all the lipolytic activity in a single proteic peak. This may help us to characterise the studied lipase. [ABSTRACT FROM AUTHOR]

The Faster Payments Service (FPS) was launched in 2008 and has witnessed significant growth since its inception. In 2010, the second full year of operation, volumes rose above anticipated levels, and new products and services supported by this 24x7 immediate payment capability are starting to evolve. VocaLink has undertaken much work to assist banks and their customers in the implementation of FPS within their businesses and to leverage the opportunities it provides to offer improved service level agreements. Some of these innovations are markers for a convergence between card, automated clearing house and Real Time Gross Settlement payment behaviours. Studies since 2008 have witnessed a slow but significant change in customer behaviour and expectation. Accord and VocaLink conducted research in 2010 to determine consumer and small business impressions and the take up of FPS. This independent research is based on a reasonable sample size (more than 2000 individuals and 300 small and medium-sized enterprises (SMEs)), and the results point to a widespread consumer understanding of a change in payment services, but without clear understanding of FPS in itself as a service or brand proposition. It is perceived by the consumer to be the capability of a bank, rather than a network or scheme capability. A clear shift has been seen in expectation of service levels and the art of the possible. In a separate study, the benefits of a mobile bank-account-to-bank-account payment service was examined, and the SME sector's willingness to pay for such a service to reduce reliance on cheques and cash. [ABSTRACT FROM AUTHOR]

Abstract: Histo-aspartic protease (HAP) from Plasmodium falciparum is an intriguing aspartic protease due to its unique structure. Our previous study reported the first recombinant expression of soluble HAP, in its truncated form (lys77p-Leu328) (p denotes prosegment), as a thioredoxin (Trx) fusion protein Trx–tHAP. The present study found that the recombinant Trx–tHAP fusion protein aggregated during purification which could be prevented through the addition of 0.2% CHAPS. Trx–tHAP fusion protein was processed into a mature form of tHAP (mtHAP) by both autoactivation, and activation with either enterokinase or plasmepsin II. Using gel filtration chromatography as well as sedimentation velocity and equilibrium ultracentrifugation, it was shown that the recombinant mtHAP exists in a dynamic monomer–dimer equilibrium with an increasing dissociation constant in the presence of CHAPS. Enzymatic activity data indicated that HAP was most active as a monomer. The dominant monomeric form showed a K m of 2.0μM and a turnover number, k cat, of 0.036s−1 using the internally quenched fluorescent synthetic peptide substrate EDANS–CO–CH2–CH2–CO–Ala-Leu-Glu-Arg-Met-Phe-Leu-Ser-Phe-Pro–Dap–(DABCYL)–OH (2837b) at pH 5.2. [Copyright &y& Elsevier]

Abstract: Fluorescence probing, and ζ-potential measurements have been used to study the interactions between the zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethyl-ammonium]-1-propanesulphonate, CHAPS and two polyelectrolytes with different electric charge. The polyelectrolytes chosen are poly (diallyl-dimethyl-ammonium chloride), PDADMAC, and poly (sodium styrene sulphonate), PSS. Results show that the zwitterionic surfactant CHAPS interacts with both, polyanion and polycation molecules, resulting in polymer–surfactant micelles. The dominating factor in this interaction is the electrostatic attraction. We found that the ζ-potential of polymer–surfactant micelles can be modulated by the addition of different type of polyelectrolytes or modifying the polymer concentration. Using dynamic surface tension measurements we estimate the micelle dissociation rate constants. Results show that the addition of polymers increases the micelle lifetime. [Copyright &y& Elsevier]

Abstract: Analyte loss due to non-specific binding, especially container surface adsorption, is not uncommon in the quantitative analysis of urine samples. In developing a sensitive LC–MS/MS method for the determination of a drug candidate, BAF312, in human urine, a simple procedure was outlined for identification, confirmation and prevention of analyte non-specific binding to a container surface and to recover the ‘non-specific loss’ of an analyte, if no transfer has occurred to the original urine samples. Non-specific binding or container surface adsorption can be quickly identified by using freshly spiked urine calibration standards and pre-pooled QC samples during a LC–MS/MS feasibility run. The resulting low recovery of an analyte in urine samples can be prevented through the use of additives, such as the non-ionic surfactant Tween-80, CHAPS and others, to the container prior to urine sample collection. If the urine samples have not been transferred from the bulk container, the ‘non-specific binding’ of an analyte to the container surface can be reversed by the addition of a specified amount of CHAPS, Tween-80 or bovine serum albumin, followed by appropriate mixing. Among the above agents, Tween-80 is the most cost-effective. β-cyclodextrin may be suitable in stabilizing the analyte of interest in urine via pre-treating the matrix with the agent. However, post-addition of β-cyclodextrin to untreated urine samples does not recover the ‘lost’ analyte due to non-specific binding or container surface adsorption. In the case of BAF312, a dynamic range of 0.0200–20.0ng/ml in human urine was validated with an overall accuracy and precision for QC sample results ranging from −3.2 to 5.1% (bias) and 3.9 to 10.2% (CV), respectively. Pre- and post-addition of 0.5% (v/v) Tween-80 to the container provided excellent overall analyte recovery and minimal MS signal suppression when a liquid–liquid extraction in combination with an isocratic LC separation was employed. The compound was stable in 0.5% Tween-80 treated human urine QC samples for at least 24h at room temperature, after three freeze/thaw cycles with storage at ≤−60°C and for at least 3 months when stored at ≤−60°C. The current work could serve as a simple example in trouble shooting non-specific binding or container surface adsorption in quantitative analysis of urine samples. [Copyright &y& Elsevier]