OsMADS1 Regulates Grain Quality, Gene Expressions, and Regulatory Networks of Starch and Storage Protein Metabolisms in Rice.

OsMADS1 plays a vital role in regulating floret development and grain shape, but whether it regulates rice grain quality still remains largely unknown. Therefore, we used comprehensive molecular genetics, plant biotechnology, and functional omics approaches, including phenotyping, mapping-by-sequencing, target gene seed-specific RNAi, transgenic experiments, and transcriptomic profiling to answer this biological and molecular question. Here, we report the characterization of the 'Oat-like rice' mutant, with poor grain quality, including chalky endosperms, abnormal morphology and loose arrangement of starch granules, and lower starch content but higher protein content in grains. The poor grain quality of Oat-like rice was found to be caused by the mutated OsMADS1Olr allele through mapping-by-sequencing analysis and transgenic experiments. OsMADS1 protein is highly expressed in florets and developing seeds. Both OsMADS1-eGFP and OsMADS1Olr-eGFP fusion proteins are localized in the nucleus. Moreover, seed-specific RNAi of OsMADS1 also caused decreased grain quality in transgenic lines, such as the Oat-like rice. Further transcriptomic profiling between Oat-like rice and Nipponbare grains revealed that OsMADS1 regulates gene expressions and regulatory networks of starch and storage protein metabolisms in rice grains, hereafter regulating rice quality. In conclusion, our results not only reveal the crucial role and preliminary mechanism of OsMADS1 in regulating rice grain quality but also highlight the application potentials of OsMADS1 and the target gene seed-specific RNAi system in improving rice grain quality by molecular breeding.

Cell Wall Matrix Polysaccharides Contribute to Salt-Alkali Tolerance in Rice.

Salt-alkali stress threatens the resilience to variable environments and thus the grain yield of rice. However, how rice responds to salt-alkali stress at the molecular level is poorly understood. Here, we report isolation of a novel salt-alkali-tolerant rice (SATR) by screening more than 700 germplasm accessions. Using 93-11, a widely grown cultivar, as a control, we characterized SATR in response to strong salt-alkali stress (SSAS). SATR exhibited SSAS tolerance higher than 93-11, as indicated by a higher survival rate, associated with higher peroxidase activity and total soluble sugar content but lower malonaldehyde accumulation. A transcriptome study showed that cell wall biogenesis-related pathways were most significantly enriched in SATR relative to 93-11 upon SSAS. Furthermore, higher induction of gene expression in the cell wall matrix polysaccharide biosynthesis pathway, coupled with higher accumulations of hemicellulose and pectin as well as measurable physio-biochemical adaptive responses, may explain the strong SSAS tolerance in SATR. We mapped SSAS tolerance to five genomic regions in which 35 genes were candidates potentially governing SSAS tolerance. The 1,4-ß-D-xylan synthase gene OsCSLD4 in hemicellulose biosynthesis pathway was investigated in details. The OsCSLD4 function-disrupted mutant displayed reduced SSAS tolerance, biomass and grain yield, whereas the OsCSLD4 overexpression lines exhibited increased SSAS tolerance. Collectively, this study not only reveals the potential role of cell wall matrix polysaccharides in mediating SSAS tolerance, but also highlights applicable value of OsCSLD4 and the large-scale screening system in developing SSAS-tolerant rice.

Association between caloric adequacy and short-term clinical outcomes in critically ill patients using a weight-based equation: Secondary analysis of a cluster-randomized controlled trial.

Background: There is controversy over the optimal energy delivery in intensive care units (ICUs). In this study, we aimed to evaluate the association between different caloric adequacy assessed by a weight-based equation and short-term clinical outcomes in a cohort of critically ill patients. Methods: This is a secondary analysis of a cluster-randomized controlled trial (N = 2,772). The energy requirement was estimated as 25 kcal/kg of body weight. The study subjects were divided into three groups according to their caloric adequacy as calculated by the mean energy delivered from days 3 to 7 of enrollment divided by the estimated energy requirements: (1) received < 70% of energy requirement (hypocaloric), (2) received 70-100% of energy requirement (normocaloric), and (3) received > 100% of energy requirement (hypercaloric). Cox proportional hazards models were used to analyze the association between caloric adequacy and 28-day mortality and time to discharge alive from the ICU. Results: A total of 1,694 patients were included. Compared with normocaloric feeding, hypocaloric feeding significantly increased the risk of 28-day mortality (hazard ratio [HR] = 1.590, 95% confidence interval [CI]: 1.162-2.176, p = 0.004), while hypercaloric feeding did not. After controlling for potential confounders, the association remained valid (adjusted HR = 1.596, 95% CI: 1.150-2.215, p = 0.005). The caloric adequacy was not associated with time to discharge alive from the ICU in the unadjusted and the adjusted models. Conclusion: Energy delivery below 70% of the estimated energy requirement during days 3-7 of critical illness is associated with 28-day mortality. Clinical trial registration: [https://www.isrctn.com/ISRCTN12233792], identifier [ISRCTN12233792].

Incidence and risk factors of nasogastric feeding intolerance in moderately-severe to severe acute pancreatitis.

BACKGROUND: The importance of enteral nutrition (EN) in acute pancreatitis (AP) has been emphasised. Nasogastric (NG) feeding has been the preferred route for EN delivery in most AP patients intolerant to oral intake. However, gastric feeding intolerance (GFI) was frequently reported, especially in patients with more severe diseases. This study aimed to investigate the incidence and risk factors for GFI in moderately-severe to severe AP. METHODS: This is a single-centre, retrospective study. All the data were extracted from an electronic database from April 2020 to May 2021. Data were prospectively collected during hospitalisation. Patients diagnosed with moderately-severe to severe AP and admitted within seven days from the onset of abdominal pain were assessed for eligibility. Patients who showed signs of intolerance to gastric feeding and required switching to nasojejunal (NJ) feeding were deemed GFI. Multivariable logistic regression was performed to assess potential risk factors of GFI. RESULTS: A total of 93 patients were analysed, of whom 24 were deemed GFI (25.8%), and the rest tolerated NG feeding well (n = 69). In patients with GFI, the median time of switching to NJ feeding was five days (interquartile range: 4-7 days) after admission. The multivariable analysis showed that respiratory failure (odds ratio = 3.135, 95% CI: 1.111-8.848, P = 0.031) was an independent risk factor for GFI.The mean daily energy delivery in the following three days after switching to NJ feeding was significantly higher than the first three days after initiation of NG feeding in patients with GFI [920.83 (493.33-1326) vs. 465 (252.25-556.67) kcal, P < 0.001]. CONCLUSION: GFI is common in moderately-severe to severe AP patients with an incidence of 25.8%, and the presence of respiratory failure may increase the risk of GFI.

A case-control study of risk factors for survival after laparotomy in patients with pancreatic trauma.

BACKGROUND: Pancreatic trauma results in significant morbidity and mortality. However, few studies have investigated the postoperative prognostic factors in patients with pancreatic trauma. MATERIAL AND METHODS: A retrospective study was conducted on consecutive patients with pancreatic trauma who underwent surgery in a national referral trauma center. Clinical data were retrieved from the electronic medical system. Univariate and binary logistic regression analyses were performed to identify the perioperative clinical parameters that may predict the factors of mortality of the patients. RESULTS: A total of 150 patients underwent laparotomy due to pancreatic trauma during the study period. 128(85.4%) patients survived and 22 (14.6%) patients died due to pancreatic injury (10 patients died of recurrent intra-abdominal active hemorrhage and 12 died of multiple organ failure). Univariate analysis showed that age, hemodynamic status, and injury severe score (ISS) as well as postoperative serum levels of C-reactive protein (CRP), procalcitonin, albumin, creatinine and the volume of intraoperative blood transfusion remained strongly predictive of mortality (P < 0.05). Binary logistic regression analysis showed that the independent risk factors for prognosis after pancreatic trauma were age (P = 0.010), preoperative hemodynamic instability (P = 0.015), postoperative CRP ≥154 mg/L (P = 0.014), and postoperative serum creatinine ≥177 µmol/L (P = 0.027). CONCLUSIONS: In this single-center retrospective study, we demonstrated that preoperative hemodynamic instability, severe postoperative inflammation (CRP ≥154 mg/L) and acute renal failure (creatinine ≥177 µmol/L) were associated with a significant risk of mortality after pancreatic trauma.

Hypothalamic AMPK-induced autophagy ameliorates hypercatabolism in septic rats by regulating POMC expression.

Hypercatabolism plays a critical role in the pathogenesis of post-critical care debility in critical patients. Central nervous system may exerte a critical role in the regulation of hypercatabolism. However, little is known about the exact mechanisms of the central role. Here, we reported that actived hypothalamic AMP-activated protein kinase (AMPK)-induced autophagy modulated the expression of POMC to ameliorate hypercatabolism in septic rats. Firstly, rats were i.c.v. injected with the lentiviral vector containing shRNA against POMC. Two weeks after injections, rats were intraperitoneally injected with LPS or saline. Twenty-four hours later, blood, skeletal muscle and hypothalamus tissues were obtained. Hypercatabolism markers and neuropeptides expression were detected. Then, rats were injected with AICAR or saline into third ventricle and promptly intraperitoneally injected with LPS or saline. Twenty-four hours after infection, blood, skeletal muscle and hypothalamus tissues were obtained. Hypercatabolism, hypothalamic AMPK-induced autophagy markers and neuropeptides expression were also detected. Results showed that sepsis would decrease the level of hypothalamic autophagy accompany with the alterations of POMC expression and hypercatabolism. Knocking out hypothalamus POMC expression could significantly ameliorate hypercatabolism. Moreover, Central activation of AMPK-induced autophagy pathway via third ventricle injection of AICAR, an AMPK activator, could efficiently ameliorate hypercatabolism as well as attenuate the elevated POMC expression rather than other neuropeptides. Taken together, these results suggested that hypothalamic AMPK-autophagy pathway as a regulatory pathway for POMC expression was essential for hypercatabolism during sepsis. And hypothalamic AMPK-autophagy activation could attenuate the POMC expression to ameliorate hypercatabolism. Pharmaceuticals with the ability of activating hypothalamic AMPK-autophagy pathway may be a therapeutic potential for hypercatabolism in septic patients.