Enhanced identification of Tau acetylation and phosphorylation with an engineered aerolysin nanopore.

Posttranslational modifications (PTMs) affect protein function/dysfunction, playing important roles in the occurrence and development of tauopathies including Alzheimer's disease. PTM detection is significant and still challenging due to the requirements of high sensitivity to identify the subtle structural differences between modifications. Herein, in terms of the unique geometry of the aerolysin (AeL) nanopore, we elaborately engineered a T232K AeL nanopore to detect the acetylation and phosphorylation of Tau segment (Pep). By replacing neutral threonine (T) with positively charged lysine (K) at the 232 sites, the T232K and K238 rings of this engineered T232K AeL nanopore corporately work together to enhance electrostatic trapping of the acetylated and phosphorylated Tau peptides. Translocation speed of the monophosphorylated Pep-P was decelerated by up to 46 folds compared to the wild-type (WT) AeL nanopore. The prolonged residences within the T232K AeL nanopore enabled to simultaneously identify the monoacetylated Pep-Ac, monophosphorylated Pep-P, di-modified Pep-P-Ac and non-modified Pep. The tremendous potential is demonstrated for PTM sensing by manipulating non-covalent interactions between nanopores and single analytes.

Is the Volume Exclusion Model Practicable for Nanopore Protein Sequencing?

The nanopore approach holds the possibility for achieving single-molecule protein sequencing. However, ongoing challenges still remain in the biological nanopore technology, which aims to identify 20 natural amino acids by reading the ionic current difference with the traditional current-sensing model. In this paper, taking aerolysin nanopores as an example, we calculate and compare the current blockage of each of 20 natural amino acids, which are all far from producing a detectable current blockage difference. Then, we propose a modified solution conductivity of σ' in the traditional volume exclusion model for nanopore sensing of a peptide. The σ' value describes the comprehensive result of ion mobility inside a nanopore, which is related to but not limited to nanopore-peptide interactions, and the positions, orientations, and conformations of peptides inside the nanopore. The nanopore experiments of a short peptide (VQIVYK) in wild type and mutant nanopores further demonstrate that the traditional volume exclusion model is not enough to fully explain the current blockage contribution and that many other factors such as enhanced nanopore-peptide interactions could contribute to a dominant part of the current change. This modified sensing model provides insights into the further development of nanopore protein sequencing methods.

Biological Nanopore Approach for Single-Molecule Protein Sequencing.

Proteins are responsible for the occurrence and treatment of many diseases, and therefore protein sequencing will revolutionize proteomics and clinical diagnostics. Biological nanopore approach has proved successful for single-molecule DNA sequencing, which resolves the identities of 4 natural deoxyribonucleotides based on the current blockages and duration times of their translocations across the nanopore confinement. However, open challenges still remain for biological nanopores to sequentially identify each amino acid (AA) of single proteins due to the inherent complexity of 20 proteinogenic AAs in charges, volumes, hydrophobicity and structures. Herein, we focus on recent exciting advances in biological nanopores for single-molecule protein sequencing (SMPS) from native protein unfolding, control of peptide translocation, AA identification to applications in disease detection.

Myopia: Its Status and Environmental Correlations Among School Students in Fushun, China.

Our objective was to investigate the status and influence of myopia among primary school students in Fushun, Liaoning Province, China. We aimed to provide a theoretical and epistemological basis for implementing myopia prevention initiatives. We employed cluster sampling and surveyed 5216 primary school students from grades 1-6 across eight primary schools in Fushun City. Our participants included 2606 males and 2610 females whose average age was 9.25 (SD = 1.76) years. The rate of myopia among these primary school students was 29.54%, with statistically significant differences among students of different genders and grades. Logistic regression analysis further identified several possible protective factors, including appropriate reading distance, adequate home lighting, regular breaks between classes, conscientious eye exercises, and daily outdoor physical activity. Conversely, the associated risk factors were being female, being in a higher grade level, spending more than 4 hours on homework, occasionally reading while lying down, and having one or both parents with myopia. Overall, our results indicated a high incidence of myopia, highlighting the need for scientifically controlled interventions to manage and mitigate the occurrence and progression of myopia in this population.

Corrigendum: Effects of Gender of Reciprocal Chromosomal Translocation on Blastocyst Formation and Pregnancy Outcome in Preimplantation Genetic Testing.

[This corrects the article DOI: 10.3389/fendo.2021.704299.].

Effects of Gender of Reciprocal Chromosomal Translocation on Blastocyst Formation and Pregnancy Outcome in Preimplantation Genetic Testing.

Objective: To determine the effect of gender of reciprocal chromosomal translocation on blastocyst formation and pregnancy outcome in preimplantation genetic testing, including different parental ages. Methods: This was a retrospective cohort study that enrolled 1034 couples undergoing preimplantation genetic testing-structural rearrangement on account of a carrier of reciprocal chromosomal translocation from the Reproductive Medicine Center of the First Affiliated Hospital of Zhengzhou University from January 2015 to December 2019. Group A represented 528 couples in which the man was the carrier of reciprocal translocation and group B represented 506 couples in which the woman was the carrier of reciprocal translocation. All patients were divided into two groups according to their age: female age<35 and female age≥35. Furthermore, the differences in blastocyst condition and pregnancy outcome between male and female carriers in each group were further explored according to their father's age. Results: The blastocyst formation rate of group A (55.3%) is higher than that of group B (50%) and the results were statistically significant (P<0.05). The blastocyst formation rate of group A is higher than that of group B, no matter in young maternal age or in advanced maternal age (P<0.05). The blastocyst formation rate in maternal age<35y and paternal age<30y in group A(57.1%) is higher than that of Group B(50%); Similarly, the blastocyst formation rate in maternal age≥35 and paternal age≥38y(66.7%) is higher than that of Group B(33.3%)(all P<0.05). There was no difference in fertilization rate, aeuploidy rate, clinical pregnancy rate, miscarriage rate and live birth rate between Group A and Group B. Conclusion: When the carrier of reciprocal translocation is male, the blastocyst formation rate is higher than that of female carrier. While there is no significant difference between the two in terms of fertilization rate, aeuploidy rate, clinical pregnancy rate, miscarriage rate and live birth rate.