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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]

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.)