Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis

Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. © 2016 Wang et al

The versatile application of cervicofacial and cervicothoracic rotation flaps in head and neck surgery

<p>Abstract</p> <p>Background</p> <p>The large defects resulting from head and neck tumour surgeries present a reconstructive challenge to surgeons. Although numerous methods can be used, they all have their own limitations. In this paper, we present our experience with cervicofacial and cervicothoracic rotation flaps to help expand the awareness and application of this useful system of flaps.</p> <p>Methods</p> <p>Twenty-one consecutive patients who underwent repair of a variety of defects of the head and neck with cervicofacial or cervicothoracic flaps in our hospital from 2006 to 2009 were retrospectively analysed. Statistics pertaining to the patients' clinical factors were gathered.</p> <p>Results</p> <p>Cheek neoplasms are the most common indication for cervicofacial and cervicothoracic rotation flaps, followed by parotid tumours. Among the 12 patients with medical comorbidities, the most common was hypertension. Defects ranging from 1.5 cm × 1.5 cm to 7 cm × 6 cm were reconstructed by cervicofacial flap, and defects from 3 cm × 2 cm to 16 cm × 7 cm were reconstructed by cervicothoracic flap. The two flaps also exhibited versatility in these reconstructions. When combined with the pectoralis major myocutaneous flap, the cervicothoracic flap could repair through-and-through cheek defects, and in combination with a temporalis myofacial flap, the cervicofacial flap was able to cover orbital defects. Additionally, 95% patients were satisfied with their resulting contour results.</p> <p>Conclusions</p> <p>Cervicofacial and cervicothoracic flaps provide a technically simple, reliable, safe, efficient and cosmetic means to reconstruct defects of the head and neck.</p

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Chilling sensitive mutants potentially defective in chloroplast-localized proteins.

<p>Chilling sensitive mutants potentially defective in chloroplast-localized proteins.</p

Chilling sensitivity of the <i>RNP</i> mutants.

<p>(A) Shown are wild type Col-0, <i>orrm1</i>, and <i>aml1</i> mutants grown for 2 months at 4°C on the plate under a 16 h light/day photoperiod. Representative chilling sensitive phenotypes are shown. (B) Shown are wild type Col-0, <i>rbd1-1</i>, <i>orrm1</i>, <i>aml1</i>, <i>cp29a</i>, and <i>cp31a</i> mutants grown at 22°C and 4°C. Top row: Plants grown for 3 weeks at 22°C under a 12 hour (h) light photoperiod. Bottom row: Plants grown for 3 weeks at 22°C, then shifted to 4°C for additional 4 weeks under a 12 h light photoperiod. (C) Shown are fresh weights of the 5 <i>RNP</i> mutants grown at 22°C and 4°C for 3 weeks and 10 weeks respectively under a 12 h light photoperiod.</p

Expression of <i>CBF</i> and <i>COR</i> genes in <i>rbd1-1</i> mutant.

<p>(A-B) Expression level of <i>CBF1</i>, <i>CBF2</i> and <i>CBF3</i> (A) and <i>COR15A</i>, <i>KIN1</i> and <i>COR47</i> (B) after 4°C treatment at different time points. RNAs were isolated from five newly emerging leaves from 2 weeks old plants grown at normal condition followed by 4°C treatment. The <i>Actin</i> gene was used as a normalization control and the experiments were repeated three times with similar results (A). Equal loading was controlled by cytosolic 25S rRNA (25S) stained with ethidium bromide (B). (C) The expression patterns of <i>RBD1</i> under 4°C. Total RNA was extracted from two weeks old plants chilling-treated for 3, 7, 14 and 21 days. The <i>Actin</i> gene was used as a normalization control. The experiments were repeated three times with similar results.</p

Chloroplast translation is inhibited in the <i>rbd1</i> mutants.

<p>(A) Total RNAs were fractionated on 1.2% formaldehyde gels and stained with ethidium bromide. (B) RNA blotting analysis of 23S rRNA processing. Total RNAs extracted from leaves were fractionated on 1.2% formaldehyde gels and hybridized to a probe (indicated by a black bar) detecting the 3’-end of the 23S rRNA. Equal loading was controlled by the cytosolic 25S rRNA (25S) stained with ethidium bromide. Processing sites in the 23S rRNA precursor were indicated by scissors. Marked numbers indicate the relative amount in the mutant compared to that in Col-0 quantified by Image J. (C) Coomassie Blue staining of total proteins from the wild type and the <i>rbd1</i> mutants after SDS-PAGE separation. Accumulation of Rubisco Large Subunit (RbcL) is indicated by an arrow. (D) Shown are Col-0, <i>rbd1</i> mutants and complementation lines grown on solid media in the presence or absence of spectinomycin at 3 mg/L for 7 days. For A, B, and C, plants were grown for 3 weeks at normal condition followed by 4°C for 4 weeks, and tissues were collected from five newly emerged leaves.</p