Mortality parameter estimates from a two-phase Gompertz fit to daily mortality of adult <i>Calliphora stygia</i> maintained at different ambient temperatures.

%<p>Initial mortality, calculated as the average mortality over the first five-days, was invariant between constant temperatures as compared by Kruskal- Wallis ANOVA (<i>K-W = </i>0.65, <i>df = </i>5, <i>P</i>>0.05).</p><p>Daily mortality data were fitted by both single linear regression and segmental linear regression, the latter giving two phases of ageing (1^st and 2^nd) and a time point at which the two phases intersect (length of 1^st period). For each temperature treatment these two equations were compared by an AICc comparison to determine the most likely model to have generated the data, R² values are given for each fit. In the temperature transfer experiment, mortality curves were applied immediately following the transfer.</p><p>For each mortality parameter, populations are compared between temperature pairs by an <i>F-</i>test (<i>P</i><0.01). Values that share the same letter are not significantly different (lowercase letters compare constant temperatures, uppercase letters are used to compare between temperature transfer populations).</p>#<p>The 1^st phase of ageing was also tested to determine whether the rate of ageing (i.e. the slope of the line) was significantly different from zero. Slopes that were not significantly different from zero are denoted by ^#.</p

Frequency and duration of egg laying of female <i>Calliphora stygia</i> kept at different ambient temperatures.

<p>Individual data points represent the days on which the presence of eggs on food dishes was recorded. The box around the data indicates the female maximum lifespan for each temperature treatment. (A) Flies kept at constant ambient temperatures (<i>n = </i>351; 388; 379; 402; 399; and 401 from 12°C to 34°C respectively). (B) Flies undergoing temperature transfer regime. The red dotted line shows the time of the temperature transfer (<i>n = </i>389, 397, 399, 399, 376, and 388, listed from the top to bottom categories respectively).</p

Food consumption of adult <i>Calliphora stygia</i> maintained at different constant temperatures.

<p>(A) Food consumption over time of flies maintained at the six different ambient temperatures. Data are from pooled replicate cages and averaged over a five-day period. Error bars are omitted for clarity. (B) Average daily food consumption of flies was significantly less at very low temperatures (12°C and 15°C), however there were no significant differences in average food consumption between the moderate to high temperatures (20°C to 34°C). Values are means ± SEM. ** is <i>P</i><0.001; *** is <i>P</i><0.0001. (C) Average lifetime food consumption per fly was calculated as the average daily food consumption per fly multiplied by average lifespan (in days).</p

Demographic and cellular senescence of adult <i>Calliphora stygia</i> maintained at different ambient temperatures.

<p>(A) A two-phase Gompertz was fitted to daily log-transformed mortality by segmental regression and is represented by the solid line for each temperature (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073781#pone-0073781-t002" target="_blank">Table 2</a> for parameters). Data are pooled from replicate cages, with plotted points being the average of a five-day period, with error bars ± one SEM (<i>N</i> = 12°C = 685, 15°C = 733, 20°C = 742, 25°C = 746, 29°C = 618, and 34°C = 778). (B) The exponential relationship between 1^st and 2^nd-phase rate of ageing and temperature. Data points are the average (± one SEM) rate of ageing during 1st- and 2^nd-phases of ageing. (C) Fluorescent AGE pigment accumulation with chronological age for each temperature treatment. Values are means ± SEM (<i>N</i> = 6). ** represents a significant difference between temperatures at that age. (D) Temperature sensitivity of AGE pigment as described by the <i>Q</i>₁₀ of the rate of accumulation of fluorescent AGE pigment. Data points are the means ± SEM of the rate of accumulation at each temperature.</p

Relationship between food consumption and lifespan of individually-maintained flies.

<p>Daily food consumption of flies that were kept individually at 25°C (<i>N = </i>10 females and 9 males). (A) Average daily food consumption of adult flies fed <i>ad libitum</i>. Data points are averaged over all flies for a 5-day period, error bars are ± one SEM. (B) Average food consumption of each individual over their entire lifetime showed no negative relationship between average daily food consumption and lifespan as would be predicted by the rate of living theory (<i>F</i>_{1, 17} = 4.115, <i>P</i>>0.05). Data points are the average daily food consumption of an individually-maintained fly, with error bars ± one SEM. (C) Total lifetime food consumption was calculated per individual by multiplying average food consumption by total longevity. There was a significant positive relationship between lifetime food consumption and lifespan (<i>F</i>_{1, 17} = 13.7, <i>P</i><0.01).</p

Longevity of adult <i>Calliphora stygia</i> maintained at different ambient temperatures.

<p>All values are means ± SEM. Maximum longevity is calculated as the average longevity of the five % longest-lived animals for each group. Average and maximum longevities are compared between temperatures by Kruskal-Wallis ANOVA with temperature pairs compared using Dunn’s multiple comparison post-hoc test (Average longevity: <i>K-W = </i>1984, <i>df = </i>5, <i>P</i><0.0001; Maximum longevity: <i>K-W = </i>200.8, <i>df = </i>5, <i>P</i><0.0001). Flies undergoing temperature transfer were compared to the 15°C and 29°C populations by Kruskal-Wallis ANOVA with temperature pairs compared using Dunn’s multiple comparison post-hoc test (Average longevity: <i>K-W</i> = 1984, <i>df = </i>5, <i>P</i><0.0001, Maximum longevity: <i>K-W</i> = 200.0, <i>df = </i>5, <i>P</i><0.0001). Values that do not share the same letter are statistically significantly different (<i>P</i><0.01), lowercase letters are used for comparisons between the constant temperature populations, uppercase letters are used for comparisons between the temperature transfer experiments.</p

Cellular and demographic senescence of adult <i>Calliphora stygia</i> transferred between high (29°C) and low (15°C) temperatures.

<p>(A) Age-specific mortality of flies that were transferred between temperatures after 14 days. Data are presented with data points calculated as an average of a five-day period (error bars are omitted for clarity). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073781#pone-0073781-t002" target="_blank">Table 2</a> for analyses of slopes. (B) Age-specific mortality of flies that were transferred between temperatures after 28 days. Data are presented with data points calculated as an average of a five-day period (error bars are omitted for clarity). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073781#pone-0073781-t002" target="_blank">Table 2</a> for analyses of slopes. (C) Fluorescent AGE pigment accumulation in whole body samples of flies transferred between temperatures after 14 days (represented by the vertical dotted line). Data points are means ± one SEM (<i>N</i> = 6). (D) Fluorescent AGE pigment accumulation in whole body samples of flies transferred between temperatures after 28 days (represented by the vertical dotted line). Data points are means ± one SEM (<i>N</i> = 6).</p

Evaluating the Effect of Phosphorylation on the Structure and Dynamics of Hsp27 Dimers by Means of Ion Mobility Mass Spectrometry

The quaternary structure and dynamics of the human small heat-shock protein Hsp27 are linked to its molecular chaperone function and influenced by post-translational modifications, including phosphorylation. Phosphorylation of Hsp27 promotes oligomer dissociation and can enhance chaperone activity. This study explored the impact of phosphorylation on the quaternary structure and dynamics of Hsp27. Using mutations that mimic phosphorylation, and ion mobility mass spectrometry, we show that successive substitutions result in an increase in the conformational heterogeneity of Hsp27 dimers. In contrast, we did not detect any changes in the structure of an Hsp27 12-mer, representative of larger Hsp27 oligomers. Our data suggest that oligomer dissociation and increased flexibility of the dimer contribute to the enhanced chaperone activity of phosphorylated Hsp27. Thus, post-translational modifications such as phosphorylation play a crucial role in modulating both the tertiary and quaternary structure of Hsp27, which is pivotal to its function as a key component of the proteostasis network in cells. Our data demonstrate the utility of ion mobility mass spectrometry for probing the structure and dynamics of heterogeneous proteins

Published Interactions of the Gasotransmitters.

<p>HO heme oxygenase; CSE cystathionine-γ-lyase; CBS cystathionine-β-synthase; NOS nitric oxide synthase (eNOS endothelial isoform, iNOS inducible isoform, nNOS neuronal isoform). ¹leukaemic monocyte macrophage cell line.</p><p>Published Interactions of the Gasotransmitters.</p

Structural equation model of predicted interactions of the gasotransmitters and their contribution to the regulation of microvascular blood flow at 24h postnatal age in the preterm human.

<p>The overall model (males and females combined) is presented and has a Goodness of Fit of χ² = 1.02 and RMSEA value of 0.017 (CI 0.00–0.28). Structural equation modelling examines linear causal relationships among variables, while simultaneously accounting for measurement error. The measurement error, or variance, determined in the model is 0.66 for microvascular blood flow, 0.77 for hydrogen sulphide, 0.24 for nitric oxide and 0.07 for carbon monoxide. NO was positively correlated with H₂S (p = 0.002, z = 3.05). There was an inverse correlation between CO and H₂S (p = 0.18, z = -1.34). There was a significant relationship between H₂S and microvascular blood flow (p = 0.012, z = 2.52) when the input of NO and CO to H₂S was included in the model.</p