Chronic effects of temperature on mortality in the Southeastern USA using satellite-based exposure metrics

Climate change may affect human health, particularly for elderly individuals who are vulnerable to temperature changes. While many studies have investigated the acute effects of heat, only a few have dealt with the chronic ones. We have examined the effects of seasonal temperatures on survival of the elderly in the Southeastern USA, where a large fraction of subpopulation resides. We found that both seasonal mean temperature and its standard deviation (SD) affected long-term survival among the 13 million Medicare beneficiaries (aged 65+) in this region during 2000–2013. A 1 °C increase in summer mean temperature corresponded to an increase of 2.5% in death rate. Whereas, 1 °C increase in winter mean temperature was associated with a decrease of 1.5%. Increases in seasonal temperature SD also influence mortality. We decomposed seasonal mean temperature and its temperature SD into long-term geographic contrasts between ZIP codes and annual anomalies within ZIP code. Effect modifications by different subgroups were also examined to find out whether certain individuals are more vulnerable. Our findings will be critical to future efforts assessing health risks related to the future climate change

Phosphorylation-Coupled Proteolysis of the Transcription Factor MYC2 Is Important for Jasmonate-Signaled Plant Immunity

<div><p>As a master regulator of jasmonic acid (JA)–signaled plant immune responses, the basic helix-loop-helix (bHLH) Leu zipper transcription factor MYC2 differentially regulates different subsets of JA–responsive genes through distinct mechanisms. However, how MYC2 itself is regulated at the protein level remains unknown. Here, we show that proteolysis of MYC2 plays a positive role in regulating the transcription of its target genes. We discovered a 12-amino-acid element in the transcription activation domain (TAD) of MYC2 that is required for both the proteolysis and the transcriptional activity of MYC2. Interestingly, MYC2 phosphorylation at residue Thr328, which facilitates its turnover, is also required for the MYC2 function to regulate gene transcription. Together, these results reveal that phosphorylation-coupled turnover of MYC2 stimulates its transcription activity. Our results exemplify that, as with animals, plants employ an “activation by destruction” mechanism to fine-tune their transcriptome to adapt to their ever-changing environment.</p> </div

JA-Induced Transcription of MYC2 Target Genes Requires the Proteasome.

<p>(A) Seven-day-old seedlings of <i>MYC2-GFP-12</i> were treated with 100 µM MeJA and/or 100 µM CHX for 6 h, root tissues were then examined by fluorescence microscopy. Bars = 50 µm. (B) Seven-day-old seedlings of <i>MYC2-4myc-15</i> were treated with 100 µM MeJA and/or 100 µM CHX for 6 h. Total protein extracts were analyzed by western blotting using anti-myc antibody. Ponceau S staining of RbcS served as a loading control. (C) Seven-day-old seedlings of <i>MYC2-GFP-12</i> were treated with 100 µM MeJA and/or 50 µM MG132 for indicated times, root tissues were then examined by fluorescence microscopy. Bars = 50 µm. (D) Seven-day-old seedlings of <i>MYC2-4myc-15</i> plants were treated with 100 µM MeJA and/or 50 µM MG132 for indicated times. Total protein extracts were analyzed by western blotting using an anti-myc antibody. Ponceau S staining of RbcS served as a loading control. (E) and (F) qRT-PCR analysis of MeJA-induced expression of <i>LOX2</i> (E) and <i>ORA59</i> (F) in WT and <i>myc2-2</i>. Seven-day-old seedlings were treated with 100 µM MeJA and/or 50 µM MG132 for 6 h (E) or 48 h (F) and RNAs were extracted for qRT-PCR assays. Values are mean ± SD of three technical replicates. Each experiment was repeated at least three times with similar results.</p

Phosphorylation of MYC2 at Thr328 Affect Its Transcription Activity.

<p>(A) and (B) qRT-PCR analysis of MeJA-induced expression of <i>LOX2</i> (A) and <i>ORA59</i> (B). Seven-day-old seedlings of the indicated genotypes were treated with 100 µM MeJA for 6 h (A) or 48 h (B) before tissues were harvested for RNA extraction. Values are mean ± SD of three technical replicates. Asterisks represent Student's t-test significance between pairs indicated with brackets (**, P<0.01). (C) Detached leaves from 4-week-old plants of the indicated genotypes were inoculated with <i>B. cinerea</i> spores for 3 d. Symptoms on rosette leaves were shown and lesion sizes (mm⁻²) were measured. Values are mean ± SD of 20 leaves from 20 plants. Asterisks denote Student's t-test significance compared with WT plants: **, P<0.01. Each experiment was repeated at least three times with similar results.</p

The Destruction Element of the MYC2 Protein Overlaps with Its TAD.

<p>(A) Schematic representation of MYC2 structural domains. TAD: transcriptional activation domain. DE: destruction element. PS: predicted phosphorylation sites. bHLH: basic helix-loop-helix domain. (B) Yeast assays showing that the activation domain of MYC2 locates in amino acid from 149 to 188. Based on the schematic protein structure of MYC2 (<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003422#pgen-1003422-g004" target="_blank">Figure 4A</a>), full length MYC2 or MYC2ΔTAD were tested for transcriptional activation. The right panels shows one-tenth and one-hundred dilution yeast growth in media. (C) Seven-day-old seedlings of <i>MYC2-GFP-12</i> and <i>MYC2^ΔDE-GFP-6</i> were treated with 100 µM CHX for 6 h. Total protein was analyzed by western blotting using an anti-GFP antibody. Ponceau S staining of RbcS served as a loading control. (D) Seven-day-old seedlings of <i>MYC2-GFP-12</i> and <i>MYC2^ΔDE-GFP-6</i> were treated with 100 µM MeJA and/or 50 µM MG132 for indicated times, root tissues were examined by fluorescence microscopy. Bars = 50 µm. Each experiment was repeated at least three times with similar results.</p

Temporal Correlation of JA-Induced Expression of <i>LOX2</i> and <i>PDF1.2</i> with JA-Induced Accumulation of the MYC2 Protein.

<p>(A–C) Time-course expression of <i>LOX2</i> (A), <i>PDF1.2</i> (B) and <i>MYC2</i> (C) in response to MeJA treatment. Seven-day-old seedlings were treated with 100 µM MeJA for indicated times before total RNAs were extracted for qRT-PCR assays. Values are mean ± SD of three technical replicates. (D) Time-course accumulation of the MYC2-myc fusion protein in MeJA-treated <i>MYC2-4myc-15</i> seedlings. Seedlings treatment was performed as in (A–C) and the MYC2-myc fusion protein was detected with an anti-myc antibody. Ponceau S staining of RbcS served as a loading control. Each experiment was repeated for at least three times with similar results.</p

Phosphorylation of MYC2 at Thr328 Affects Its Turnover.

<p>(A) Total protein of <i>MYC2-4myc-15</i> plants was extracted and immunoprecipitated with an anti-myc antibody. Immunoprecipitated proteins were treated with alkaline phosphatase for 30 min then analyzed by western blotting using an anti-myc antibody. (B) <i>MYC2-4myc-15</i> transgenic plants were treated with or without 100 µM MeJA for 6 h. Total proteins containing equal amount of MYC2-4myc were loaded on a column that specifically binds phospho-proteins. Bound proteins were eluted and the amount of MYC2-4myc determined by western blotting with an anti-myc antibody. (C) Identification of MYC2 phosphorylation at Thr328 by mass spectrometry. Shown is a collision-induced dissociation mass spectrum of the phosphopeptide SIQFENGSSSTITENPNLDP(pT)PSPVHSQTQNPK (+3 charged, <i>m/z</i> 1212.22). The C-terminal fragments (<i>y</i> ions) are colored orange and the N-terminal fragments (<i>b</i> ions) are colored green. ^* and ^# indicate fragment ions with a neutral loss of phosphoric acid or H₂O, respectively. (D) Root growth inhibition assay of the transgenic plants as indicated. Seeds were germinated on 1/2 MS medium with or without 20 µM MeJA after 3 d stratification; photos were taken 8 d after germination. (E) <i>MYC2-4myc-10</i> and <i>MYC2^T328A-4myc-23</i> plants were treated for 6 h with 100 µM MeJA and/or 100 µM CHX. Total protein was analyzed by western blotting using an anti-myc antibody. Ponceau S staining of RbcS served as a loading control. (F) <i>MYC2-4myc-10</i> and <i>MYC2^T328A-4myc-23</i> plants were treated for 6 h with 100 µM MeJA and/or 50 µM MG132. Total protein was analyzed by western blotting using anti-myc antibody. Ponceau S staining of RbcS served as a loading control.</p