Data_Sheet_1_Dose–response relationship between multiple trace elements and risk of all-cause mortality: a prospective cohort study.docx

ObjectivesWe aimed to prospectively investigate the independent and combined relationship between trace elements concentrations [blood (selenium, manganese), serum (copper, zinc), and urine (cobalt, molybdenum, tin, strontium, iodine)] and all-cause mortality.MethodsThis study included 5,412 individuals with demographical, examination, and laboratory data from the National Health and Nutrition Examination Survey. Three statistical models, including Cox proportional hazards models, restricted cubic spline models, and Bayesian kernel machine regression (BKMR) models, were conducted to estimate the longitudinal relationship between trace elements and all-cause mortality.ResultsThere were 356 deaths documented with a median follow-up time of 70 months. In the single-exposure model, the results showed that compared with the lowest quartile, the adjusted hazard ratios (HRs) of mortality for the highest quartile of selenium, manganese, and strontium were 0.47 (95% CI: 0.28–0.79), 1.57 (95% CI: 1.14–2.14), and 0.47 (95% CI: 0.26–0.86), respectively. A nonlinear relationship between zinc, cobalt and mortality was also observed. Furthermore, a significant overall effect of mixtures of trace elements on all-cause mortality was identified, especially when the mixture was at the 60th percentile or lower.ConclusionThe association of multiple trace elements with all-cause mortality was identified in this study. It is recommended that healthcare providers and relevant public health agencies should strengthen the surveillance and management of trace elements. Emphasis should be placed on monitoring the sources of trace elements such as the body, food, and environment. More population studies and animal experiments should be conducted to identify the underlying mechanisms.</p

Activity-Dependent Modulation of Odorant Receptor Gene Expression in the Mouse Olfactory Epithelium

<div><p>Activity plays critical roles in development and maintenance of the olfactory system, which undergoes considerable neurogenesis throughout life. In the mouse olfactory epithelium, each olfactory sensory neuron (OSN) stably expresses a single odorant receptor (OR) type out of a repertoire of ∼1200 and the OSNs with the same OR identity are distributed within one of the few broadly-defined zones. However, it remains elusive whether and how activity modulates such OR expression patterns. Here we addressed this question by investigating OR gene expression via in situ hybridization when sensory experience or neuronal excitability is manipulated. We first examined the expression patterns of fifteen OR genes in mice which underwent neonatal, unilateral naris closure. After four-week occlusion, the cell density in the closed (sensory-deprived) side was significantly lower (for four ORs), similar (for three ORs), or significantly higher (for eight ORs) as compared to that in the open (over-stimulated) side, suggesting that sensory inputs have differential effects on OSNs expressing different OR genes. We next examined the expression patterns of seven OR genes in transgenic mice in which mature OSNs had reduced neuronal excitability. Neuronal silencing led to a significant reduction in the cell density for most OR genes tested and thinner olfactory epithelium with an increased density of apoptotic cells. These results suggest that sensory experience plays important roles in shaping OR gene expression patterns and the neuronal activity is critical for survival of OSNs.</p></div

The cell density for most OR types decreases in OMP-Kir2.1 mice.

<p>The averaged cell density per linear length is denoted as cell number ± s.e.m./mm (<i>n</i> = number of sections). The wild-type data were combined from littermate controls (Kir2.1 negative) and untreated C57Bl/6 mice. The p values were obtained by unpaired, two-tailed <i>t</i> tests.</p

The thickness of mature OSN layer does not differ significantly between the closed and open side.

<p>Coronal sections from 4-week-old mice that underwent neonatal, unilateral naris closure were stained with antibodies against OMP (red) and a neuronal marker Tuj1 (green). (A) A low-magnification image shows an entire section. Scale bar = 0.5 mm. The rectangles indicate the approximate locations where confocal images in B to E were taken. The dashed lines illustrate how the thickness of the mature OSN layer is measured in defined regions of zone 1 and zone 4. (B–E) High-magnification confocal images (projected from a stack of 5 images with z step = 3 µm) were taken from zone 1 and zone 4 in the closed (B, D) and open side (C, E). Scale bars = 20 µm.</p

Naris closure causes differential changes in the cell density for different OR genes.

<p>The averaged cell density per linear length is denoted as cell number ± s.e.m./mm (<i>n</i> = number of sections). Pattern 1 (similar in both sides) is in regular script, Pattern 2 (closeditalic, and Pattern 3 (closed>open) in <b>bold</b>. * Cells expressing MOR174-13 were found in both the mediodorsal and intermediate zones. ** Cells expressing MOR0-2 were found in both the intermediate and lateroventral zones.</p

Naris closure induces higher expression levels in the closed side for most OR genes expressed in the lateroventral zone 4.

<p>Log2 ratio (x/o), the expression level ratio between the closed (x) and open (o) side, and the p value were obtained from the microarray study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069862#pone.0069862-Coppola2" target="_blank">[19]</a>. Pattern 1 (similar in both sides) is in regular script and Pattern 3 (closed>open) in <b>bold</b>. The OR genes are sorted based on the log2 ratio and only significant changes (p<0.05) are in <b>bold</b>.</p

Unilateral naris closure differentially alters the cell density of individual OR genes.

<p>(A) The linear length from a coronal section was determined by outlining the basement membrane which separates the olfactory epithelium from the propria lamina. The rectangles indicate the approximate locations from which images in B–D were taken. (B–D) The coronal sections were hybridized with antisense RNA probes of MOR13-4 (dorsal zone, B), MOR174-13 (intermediate zone, C), and MOR244-3 (ventral zone, D). The two images in D were taken under identical conditions from the same section and the staining in the open side appeared much weaker than that in the closed side. Arrows mark examples of labeled cells. Scale bar = 0.5 mm in A and 0.2 mm in B–D.</p

Genomic Characterization of Novel <i>Listeria monocytogenes</i> Serotype 4b Variant Strains

<div><p>Over 90% of the human listeriosis cases are caused by <i>Listeria monocytogenes</i> serotypes 1/2a, 1/2b and 4b strains. As an alternative to antigen-antibody based serotyping, a PCR-based method for serogrouping has been developed and validated. In this communication, we report an in-depth analysis of five 4b variant strains, four clinical isolates from Australia and one environmental isolate from USA. Although these five strains were serotype 4b by classical serotyping method, the serogrouping PCR profiles of these strains show the presence of a 1/2a-3a specific amplicon in addition to the standard 4b-4d-4e specific amplicons. These strains were further analyzed by pulsed field gel electrophoresis, binary gene typing, multi-locus variable-number-tandem-repeat analysis and a high density pan-genomic <i>Listeria</i> microarray. Using these sub-typing results, the clinical isolates were grouped into two distinct genomic groups- one of which could be part of an unidentified outbreak. The microarray results when compared with our database of other 4b outbreak isolates indicated that the serotype 4b variant strains represent very different genotypic profiles than the known reported 4b outbreak strains representing major epidemic clones. The acquisition of serotype 1/2a gene clusters by the 4b variant strains appears to be independent in origin, spanning large areas of geographical and temporal space and may indicate predisposition of some 4b strains towards accepting DNA from related organisms.</p></div

Multiplex PCR profiles of <i>L. monocytogenes</i> strains.

<p>Lanes: MW, Molecular weight markers. Lane 1: LS1 serotype 1/2a, Lane 2: LS402, serotype 4b; Lane3-7: serotype IVb-v1 strains LS542; LS642; LS643; LS644; LS645, respectively.</p

Unique probe-sets in 1/2a and IVb-v1 <i>L. monocytogenes</i> strains.

<p>Unique probe-sets in 1/2a and IVb-v1 <i>L. monocytogenes</i> strains.</p