DNA-Interacting Characteristics of the Archaeal Rudiviral Protein SIRV2_Gp1

Whereas the infection cycles of many bacterial and eukaryotic viruses have been characterized in detail, those of archaeal viruses remain largely unexplored. Recently, studies on a few model archaeal viruses such as SIRV2 (Sulfolobus islandicus rod-shaped virus) have revealed an unusual lysis mechanism that involves the formation of pyramidal egress structures on the host cell surface. To expand understanding of the infection cycle of SIRV2, we aimed to functionally characterize gp1, which is a SIRV2 gene with unknown function. The SIRV2_Gp1 protein is highly expressed during early stages of infection and it is the only protein that is encoded twice on the viral genome. It harbours a helix-turn-helix motif and was therefore hypothesized to bind DNA. The DNA-binding behavior of SIRV2_Gp1 was characterized with electrophoretic mobility shift assays and atomic force microscopy. We provide evidence that the protein interacts with DNA and that it forms large aggregates, thereby causing extreme condensation of the DNA. Furthermore, the N-terminal domain of the protein mediates toxicity to the viral host Sulfolobus. Our findings may lead to biotechnological applications, such as the development of a toxic peptide for the containment of pathogenic bacteria, and add to our understanding of the Rudiviral infection cycle.status: publishe

Factors related to axial length elongation and myopia progression in orthokeratology practice

<div><p>Purpose</p><p>To investigate which baseline factors are predictive for axial length growth over an average period of 2.5 years in a group of children wearing orthokeratology (OK) contact lenses.</p><p>Methods</p><p>In this retrospective study, the clinical records of 249 new OK wearers between January 2012 and December 2013 from the contact lens clinic at the Eye and ENT Hospital of Fudan University were reviewed. The primary outcome measure was axial length change from baseline to the time of review (July-August 2015). Independent variables included baseline measures of age at initiation of OK wear, gender, refractive error (spherical equivalent), astigmatism, average keratometry, corneal toricity, central corneal thickness, white-to-white corneal diameter, pupil size, corneal topography eccentricity value (e-value), intraocular pressure (IOP) and total time in follow-up (months total). The contributions of all independent variables on axial length change at the time of review were assessed using univariate and multivariable regression analyses.</p><p>Results</p><p>Univariate analyses of the right eyes of 249 OK patients showed that smaller increases in axial length were associated with older age at the onset of OK lens wear, greater baseline spherical equivalent myopic refractive error, less time in follow-up and a smaller e-value. Multivariable analyses of the significant right eye variables showed that the factors associated with smaller axial length growth were older age at the onset of OK lens wear (p<0.0001), greater baseline spherical equivalent myopic refractive error (p = 0.0046) and less time in follow-up (p<0.0001).</p><p>Conclusions</p><p>The baseline factors demonstrating the greatest correlation with reduced axial length elongation during OK lens wear in myopic children included greater baseline spherical equivalent myopic refractive error and older age at the onset of OK lens wear.</p></div

Near Work Related Behaviors Associated with Myopic Shifts among Primary School Students in the Jiading District of Shanghai: A School-Based One-Year Cohort Study

<div><p>Purpose</p><p>To investigate the characteristics of various near work related behaviors among primary students and their associations with changes in myopia related ocular biometric parameters during one-year of follow up.</p><p>Methods</p><p>A school-based sample of 4,814 primary 1^st to 4^th grade students aged 6–10 years old were selected by cluster randomization based on probability proportion to size in 2013. At baseline, students together with their parents filled in a self-administered questionnaire on 9 aspects of near work related behaviors and some important covariants of myopia. A comprehensive set of eye examinations including axial length (AL) and cycloplegic refraction was conducted both at baseline and one year later.</p><p>Results</p><p>With the grade level increase, students did increasingly better at finding various ways to have an eye break, but they were increasingly likely to continuously do long-time near work without an eye break. Keeping a reasonable eye distance and correct hand posture for reading, writing, or watching TV became worse for the first time before grade 2, but then became better at grade 3. In contrast, selecting appropriate lighting environments or situations and keeping a balanced diet became better for the first time before grade 2, but then became worse at grade 3. At one-year follow up, the mean AL increased by 0.32 ± 0.35 mm, the ratio of AL divided by the mean corneal radius of curvature (AL/CR ratio) increased by 0.032 ± 0.054, the myopic spherical equivalent (SE) increased by -0.51 ± 0.51 diopters and the incidence of myopia was 16.0% (237/1,477). After controlling for the confounding effects of parental myopia, student’s age, gender, height, daily near work time, daily outdoor activity time and all of the other near work related behaviors, keeping a reasonable distance when reading, writing and watching TV was associated with elongation of the AL [standard coefficient beta = -0.062, <i>P</i> = 0.004], a change in SE [beta = -0.072, <i>P</i> = 0.020] and incident myopia [adjusted odds ratio (aOR) = 0.90, 95% confidence interval (CI): 0.84–0.96]. Selecting an environment with adequate light for visual comfort to read and write was related to elongation of the AL [beta = -0.039, <i>P</i> = 0.034] and increase of AL/CR ratio [beta = -0.030, <i>P</i> = 0.048]. Also, not continuing to do near work for more than 30–40 minutes without an eye break was related to increase of the AL/CR ratio [beta = -0.028, <i>P</i> = 0.044] and a change in SE [beta = -0.064, <i>P</i> = 0.023].</p><p>Conclusion</p><p>Various near work related behaviors changed according to grade level in primary school students. Independent of hereditary factors, daily near work load and outdoor activity, near work related behaviors such as keeping an inappropriate eye distance for near work, selecting inadequate lighting environments, and continuing to do near work without an eye break were risk factors for myopic shifts.</p></div

Near work related behaviors associated with incident myopia within one year in students of grades 1 to 4 in Shanghai.

<p>Near work related behaviors associated with incident myopia within one year in students of grades 1 to 4 in Shanghai.</p

Participant characteristics.

<p>Participant characteristics.</p