Genomic Analysis of Novel Poxvirus Brazilian Porcupinepox Virus,Brazil, 2019

We obtained the complete sequence of a novel poxvirus, tentatively named Brazilian porcupinepox virus, from a wild porcupine (Coendou prehensilis) in Brazil that had skin and internal lesions characteristic of poxvirus infection. The impact of this lethal poxvirus on the survival of this species and its potential zoonotic importance remain to be investigated.     

Ferroelectric switching of elastin

Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm², whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications.Ferroelectricity was first discovered in synthetic materials in 1920 when spontaneous polarization of Rochelle salt was found to be switchable by an external electric field (1). Ferroelectrics thus belongs to a larger class of pyroelectric materials that possess a unique polar axis, which, in turn, belongs to piezoelectrics exhibiting linear coupling between electric and mechanical fields (2). Because of these versatile properties, ferroelectric materials are promising for a wide range of technological applications in data storage, sensing, actuation, energy harvesting, and electro-optic devices (3). Biological tissues, such as bones and tendons, were first observed to be piezoelectric in 1950s (4), and shortly thereafter, pyroelectricity was discovered in a variety of biological materials as well (5, 6). Ever since then, ferroelectricity has been speculated for biological systems, and its potential physiological significance has been suggested (7). For example, it was hypothesized that the conformation transition in voltage-gated ion channels is ferroelectric in nature (8, 9). Nevertheless, indication of ferroelectricity in biological materials has only recently emerged from nanoscale piezoresponse force microscopy (PFM) studies (10–13).This work is motivated by our recent observation of PFM switching in elastin (12), which has generated quite a bit of excitement, although there is still considerable skepticism regarding the notion of biological ferroelectricity. Such reservation is understandable, given the unusual phenomenon of ferroelectric switching in biology, some ambiguities associated with PFM hysteresis, and a current lack of understanding of the basic science underpinning the switching mechanism. Indeed, there is neither macroscopic evidence of ferroelectric switching nor microscopic understanding of its molecular origin. The current work seeks to address these aforementioned issues, and thus to advance our understanding of biological ferroelectricity on two important fronts. First, we present macroscopic observation of ferroelectric switching in a biological system, derived from careful pyroelectric measurement. This dataset, in our view, decisively settles the long-standing question regarding ferroelectricity in biology. Furthermore, in close conjunction with experiments, we present a molecular-based computational study to elucidate the origin and mechanism underpinning ferroelectric switching of elastin. We show that the polarization in elastin is intrinsic at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics. Our findings thus establish ferroelectricity as an important biophysical property of proteins, and we believe this is a critical first step toward resolving its physiological significance and pathological implications.     

Immediate effects of diaphragmatic myofascial release on the physical and functional outcomes in sedentary women: A randomized placebo-controlled trial

Background

Although diaphragmatic myofascial release techniques are widely used in clinical practice, few studies have evaluated the simultaneous acute effects of these techniques on the respiratory and musculoskeletal systems.

The effect of day care attendance on infant and toddler’s growth

Aim: We aimed to study the association between day care attendance and changes in the height, weight and weight/height ratio over a 6‐month period. Methods: Data were retrieved from three maternal and child health care centres. Parents were asked to fill a short questionnaire regarding the infant/toddler life style, the day care facilities and the family demographic information. Results: One hundred and seventy infants participated in the study. The research group consisted of 85 infants that had placed in day care centre prior to the age of 18 months. The control group consisted of 85 infants who had placed in day care at a later age. The research group had significantly shorter stature 3 months after day care enrolment (mean height percentiles of 56.9 versus 66.3, respectively, p = 0.024,). This trend was more pronounced after 6 months (mean height percentiles of 52.3 versus 63.7, p = 0.022). We could not, however, demonstrate a concomitant significant deceleration in weight or weight/height percentiles. Conclusions: The explanation for this rather dramatic finding remains speculative. Possible mechanisms are stress‐related growth hormone suppression. Our findings reinforce the importance of monitoring infant/toddler weight and height growth velocities, especially when he/she is introduced to day care.     

Survival of retinal pigment epithelium after exposure to prolonged oxidative injury: a detailed gene expression and cellular analysis

PURPOSE: To detail, by DNA microarrays and cellular structure labeling, the in vitro responses of retinal pigment epithelial (RPE) cells to a nonlethal dose of the oxidant agent hydroquinone (HQ). METHODS: The viability of growth-quiescent ARPE-19 cells after treatment with HQ was measured by XTT conversion, (3)H-leucine incorporation, trypan blue exclusion, and the presence of DNA laddering. The effect of a nonlethal dose of HQ on the localization of apoptosis-induced factor (AIF) and phosphorylation of stress-activated kinase-2/p38 (SAPK2/p38) was detected by immunocytochemistry. Actin structures were visualized by phalloidin staining. Cell membrane blebbing was detected using GFP-membrane-labeled RPE cells (ARPE-GFP-c'-rRas). Changes in gene expression patterns of RPE cells within 48 hours of prolonged treatment with a nonlethal dose of HQ were evaluated by microarray analysis and confirmed by Northern blotting. RESULTS: The viability of RPE after a prolonged sublethal injury dose of HQ was determined by multiple assays and confirmed by the absence of AIF translocation or DNA laddering. Prolonged exposure (16 hours) of RPE cells to a nonlethal dose of HQ resulted in actin rearrangement into globular aggregates and cell membrane blebbing. Kinetic microarray analysis at several time points over a 48-hour recovery period revealed significant upregulation of genes involved in ameliorating the oxidative stress, chaperone proteins, anti-apoptotic factors, and DNA repair factors, and downregulation of pro-apoptotic genes. Genes involved in extracellular matrix functions were also dysregulated. Recovery of RPE cells after the injury was confirmed by the normalization of gene expression dysregulation back to baseline levels within 48 hours. CONCLUSIONS: RPE cells avoided cell death and recovered from prolonged oxidative injury by activating a host of defense mechanisms while simultaneously triggering genes and cellular responses that may be involved in RPE disease development.