Disruption of a Rice Chloroplast-Targeted Gene OsHMBPP Causes a Seedling-Lethal Albino Phenotype.

BACKGROUND: Chloroplast development is coordinately regulated by plastid- and nuclear-encoding genes. Although many regulators have been reported to be involved in chloroplast development, new factors remain to be identified, given the complexity of this process. RESULTS: In this study, we characterized a rice mutant lethal albinic seedling 1(las1)form of a 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (OsHMBPP) that was targeted to the chloroplasts. The LAS1 mutation caused the albino lethal phenotype in seedlings. Transmission electron microscopy indicated that las1 were defective in early chloroplast development. LAS1 is preferentially expressed in leaves, implying its role in controlling chloroplast development. The expression levels of many chloroplast-encoded genes were altered significantly in las1. The expression levels of nuclear-encoded gene involved in Chl biosynthesis were also decreased in las1. We further investigated plastidic RNA editing in las1 and found that the edit efficiency of four chloroplast genes were markly altered. Compared with WT, las1 exhibited defective in biogenesis of chloroplast ribosomes. CONCLUSIONS: Our results show that LAS1/OsHMBPP plays an essential role in the early chloroplast development in rice.

DS1/OsEMF1 interacts with OsARF11 to control rice architecture by regulation of brassinosteroid signaling.

BACKGROUND: Plant height and leaf angle are important determinants of yield in rice (Oryza sativa L.). Genes involved in regulating plant height and leaf angle were identified in previous studies; however, there are many remaining unknown factors that affect rice architecture. RESULTS: In this study, we characterized a dwarf mutant named ds1 with small grain size and decreased leaf angle,selected from an irradiated population of ssp. japonica variety Nanjing35. The ds1 mutant also showed abnormal floral organs. ds1 plants were insensitive to BL treatment and expression of genes related to BR signaling was changed. An F2 population from a cross between ds1 and indica cultivar 93-11 was used to fine map DS1 and to map-based clone the DS1 allele, which encoded an EMF1-like protein that acted as a transcriptional regulator. DS1 was constitutively expressed in various tissues, and especially highly expressed in young leaves, panicles and seeds. We showed that the DS1 protein interacted with auxin response factor 11 (OsARF11), a major transcriptional regulator of plant height and leaf angle, to co-regulate D61/OsBRI1 expression. These findings provide novel insights into understanding the molecular mechanisms by which DS1 integrates auxin and brassinosteroid signaling in rice. CONCLUSION: The DS1 gene encoded an EMF1-like protein in rice. The ds1 mutation altered the expression of genes related to BR signaling, and ds1 was insensitive to BL treatment. DS1 interacts with OsARF11 to co-regulate OsBRI1 expression.

[Significance of monitoring the gradients between transcutaneous PCO(2) and end-tidal PCO(2) in patients with septic shock].

Objective: To investigate the significance of monitoring the gradients between transcutaneous PCO(2) and end-tidal PCO(2) [P(c-et)CO(2)] in patients with septic shock. Method: Thirty-five mechanically ventilated patients with early septic shock were enrolled as the study group and 18 non-septic shock patients with stable hemodynamics as the control group between May 2014 and October 2016. The patients with septic shock were treated by early goal-directed therapy (EGDT) within 6 hours since hospitalization. The differences of baseline level of P(c-et)CO(2) and arterial lactate concentration (LAC) between the two groups and the variations of these indexes after EGDT in the study group were compared respectively. Results: The baseline levels of P(c-et)CO(2) and LAC in patients with septic shock were significantly higher than those of the control group [(26.0±16.2) mmHg vs (11.0±5.6) mmHg (1 mmHg=0.133 kPa) and (4.0±1.7) mmol/L vs (1.6±0.6)mmol/L, all P=0.000]. The area under receiver operator characteristic (ROC) curve (AUC) for baseline P(c-et)CO(2) and LAC was 0.924 (95%CI: 0.851-0.996) and 0.931 (95%CI: 0.872-1.000), respectively. P(c-et)CO(2) >12.6 mmHg and LAC >2.5 mmol/L could discriminate septic shock patients from those without shock with the same sensibility of 97% and the specificity of 83% and 78% respectively. With regard to the prognosis (Day 28) of the patients with septic shock, AUC for baseline P(c-et)CO(2) and LAC was 0.709 (95%CI: 0.533-0.886) and 0.714 (95%CI: 0.545-0.883), respectively. P(c-et)CO(2) >20.0 mmHg and LAC>3.6 mmol/L could discriminate survivors from non-survivors with the same sensibility of 92% and the same specificity of 76%. All the patients in the study group completed EGDT within 6 hours after admission, 20 (57.1%) passed EGDT and 17 (85.0%) survived, 15 (42.9%) failed EGDT and 4 (26.7%) survived, and the survival rates were significantly different (F=9.844, P=0.001). After EGDT, P(c-et)CO(2) (21.0±9.5 mmHg) and LAC(3.3±2.5 mmol/L)reduced significantly compared with the baselines (P=0.008 and P=0.046), and the associated AUC was 0.905(95%CI: 0.792-1.000) and 0.747 (95%CI: 0.576-0.917)respectively. P(c-et)CO(2) > 16.5 mmHg and LAC > 3.1 mmol/L could discriminate survivors from non-survivors with the sensibility of 97% and 91%, and the specificity of 78% and 69%, respectively. Conclusions: P(c-et)CO(2) >12.6 mmHg could play the same role as LAC in recognizing early septic shock. EGDT was an effective therapy for the septic shock and P(c-et)CO(2) reflected efficacy. P(c-et)CO(2)>20 mmHg before EGDT and >16.5 mmHg after EGDT both could predict the 28 d prognosis of patients with septic shock, and the effect of the former was equal to that of LAC, but the latter was better than LAC.

Hospitalisation associated with the 2009 H1N1 pandemic and seasonal influenza in Hong Kong, 2005 to 2010.

Reliable estimates of the morbidity burden caused by the 2009 pandemic influenza (pH1N1) are important for assessing the severity of the pandemic. Poisson regression models were fitted to weekly numbers of cause-specific hospitalisation in Hong Kong from 2005 to 2010. Excess hospitalisation associated with the 2009 pandemic and seasonal influenza was derived from the model by incorporating the proxy variables of weekly proportions of specimens positive for the pandemic influenza A(H1N1)pdm09, seasonal influenza A (subtypes H3N2 and H1N1) and B viruses. Compared with seasonal influenza, pH1N1 influenza was associated with higher hospitalisation rates for acute respiratory disease (ARD) among children younger than 18 years and adults aged between 18 and 64 years, but among the elderly aged 65 years and older the hospitalisation rates were lower for pH1N1 than for seasonal H3N2 and H1N1 influenza. Hospitalisation rates for chronic diseases associated with pH1N1 influenza were generally higher than those associated with seasonal influenza. The reported hospitalised cases with laboratory-confirmed pandemic infections accounted for only 16% of pH1N1 influenza-associated hospitalisations for ARD in the age group 75 years and older, and 5‒66% of hospitalisations for chronic diseases in those older than 40 years. The 2009 H1N1 influenza pandemic was associated with a dramatically increased risk of hospitalisation among children and young adults. The morbidity burden of pandemic was underreported in old people and in those with chronic conditions.