Microalgae possess high photosynthetic efficiency, robust adaptability, and substantial biomass, serving as excellent biological resources for large-scale cultivation. Malic enzyme (ME), a ubiquitous metabolic enzyme in living organisms, catalyzes the decarboxylation of malate to produce pyruvate, CO₂, and NAD(P)H, playing a role in multiple metabolic pathways including energy metabolism, photosynthesis, respiration, and biosynthesis. In this study, we identified the Scenedesmus quadricauda malic enzyme gene (SqME) and its biological functions, aiming to provide excellent target genes for the genetic improvement of higher plants. Based on the RNA-seq data from S. quadricauda under the biofilm cultivation mode with high CO₂ and light energy transfer efficiency and small water use, a highly expressed gene (SqME) functionally annotated as ME was cloned. The physicochemical properties of the SqME-encoded protein were systematically analyzed by bioinformatics tools. The subcellular localization of SqME was determined via transient transformation in Nicotiana benthamiana leaves. The biological functions of SqME were identified via genetic transformation in Nicotiana tabacum, and the potential of SqME in the genetic improvement of higher plants was evaluated. The ORF of SqME was 1 770 bp, encoding 590 amino acid residues, and the encoded protein was located in chloroplasts. SqME was a NADP-ME, with the typical structural characteristics of ME. The ME activity in the transgenic N. tabacum plant was 1.8 folds of that in the wild-type control. Heterologous expression of SqME increased the content of chlorophyll a, chlorophyll b, and total chlorophyll by 20.9%, 26.9%, and 25.2%, respectively, compared with the control. The transgenic tobacco leaves showed an increase of 54.0% in the fluorescence parameter NPQ and a decrease of 30.1% in Fo compared with the control. Moreover, the biomass, total lipids, and soluble sugars in the transgenic tobacco leaves enhanced by 20.5%, 25.7%, and 9.5%, respectively. On the contrary, the starch and protein content in the transgenic tobacco leaves decreased by 22.4% and 12.2%, respectively. Collectively, the SqME-encoded protein exhibited a strong enzymatic activity. Heterologous expressing of SqME could significantly enhance photosynthetic protection, photosynthesis, and biomass accumulation in the host. Additionally, SqME can facilitate carbon metabolism remodeling in the host, driving more carbon flux towards lipid synthesis. Therefore, SqME can be applied in the genetic improvement of higher plants for enhancing photosynthetic carbon fixation and lipid accumulation. These findings provide scientific references for mining of functional genes from S. quadricauda and application of these genes in the genetic engineering of higher plants.
Nicotiana/genetics* ; Photosynthesis/physiology* ; Malate Dehydrogenase/biosynthesis* ; Plant Leaves/genetics* ; Scenedesmus/enzymology* ; Carbon Cycle/genetics* ; Lipid Metabolism/genetics* ; Plants, Genetically Modified/metabolism*

Stearoyl-ACP Δ⁹ desaturase (SAD) catalyzes the synthesis of monounsaturated oleic acid or palmitoleic acid in plastids. SAD is the key enzyme to control the ratio of saturated fatty acids to unsaturated fatty acids in plant cells. In order to analyze the regulation mechanism of soybean oleic acid synthesis, soybean (Glycine max) GmSAD family members were genome-wide identified, and their conserved functional domains and physicochemical properties were also analyzed by bioinformatics tools. The spatiotemporal expression profile of each member of GmSADs was detected by qRT-PCR. The expression vectors of GmSAD5 were constructed. The enzyme activity and biological function of GmSAD5 were examined by Agrobacterium-mediated transient expression in Nicotiana tabacum leaves and genetic transformation of oleic acid-deficient yeast (Saccharomyces cerevisiae) mutant BY4389. Results show that the soybean genome contains five GmSAD family members, all encoding an enzyme protein with diiron center and two conservative histidine enrichment motifs (EENRHG and DEKRHE) specific to SAD enzymes. The active enzyme protein was predicted as a homodimer. Phylogenetic analysis indicated that five GmSADs were divided into two subgroups, which were closely related to AtSSI2 and AtSAD6, respectively. The expression profiles of GmSAD members were significantly different in soybean roots, stems, leaves, flowers, and seeds at different developmental stages. Among them, GmSAD5 expressed highly in the middle and late stages of developmental seeds, which coincided with the oil accumulation period. Transient expression of GmSAD5 in tobacco leaves increased the oleic acid and total oil content in leaf tissue by 5.56% and 2.73%, respectively, while stearic acid content was reduced by 2.46%. Functional complementation assay in defective yeast strain BY4389 demonstrated that overexpression of GmSAD5 was able to restore the synthesis of monounsaturated oleic acid, resulting in high oil accumulation. Taken together, soybean GmSAD5 has strong selectivity to stearic acid substrates and can efficiently catalyze the biosynthesis of monounsaturated oleic acid. It lays the foundation for the study of soybean seed oleic acid and total oil accumulation mechanism, providing an excellent target for genetic improvement of oil quality in soybean.
Fatty Acid Desaturases ; genetics ; metabolism ; Gene Expression Profiling ; Oleic Acid ; biosynthesis ; Phylogeny ; Plant Proteins ; genetics ; Seeds ; chemistry ; Soybeans ; classification ; enzymology ; genetics

Objective The bispectral index (BIS) was introduced into the sedation strategy of critical patients in intensive care unit (ICU) and replaced the Richmond agitation sedation scale (RASS).The ventilation time,ICU length of stay,and 90-day mortality were compared between the two groups of patients who performed early goal-directed sedation (EGDS) or standard traditional directed sedation (STDS) strategies.Methods A prospective controlled study of severe patients with mechanical ventilation ≥48 h in ICU (20 cases from April 2016 to May 2017,46 cases from June 2017 to April 2018) were randomly divided into EGDS or STDS group.There were no significant differences in age,gender,and acute physiology and chronic health evaluation score Ⅱ (APACHE Ⅱ) score between the two groups in the two periods.The correlation between RASS and BIS was analyzed in the first period.The BIS of the patients in a RASS range of (-2-1) was 73.65 ± 7.87 in the EGDS group,and that of RASS range of (-3--1) was 64.14 ± 7.25 in the STDS group.The above BIS was applied to the two sedation strategies in the second period respectively.The ventilation time,ICU length of stay,and 90-day mortality were recorded.Results There was no significant difference in the ventilation time between the two groups [(164.12 ± 137.96) h and (155.33 ±64.86)h,P =0.08].ICU length of stay of the EGDS group was longer than that of the STDS group.The 90-day mortality of the EGDS group was higher than that of the STDS group.Conclusions Correlations between RASS and BIS were found in this study,and BIS can be used for sedation assessment in ICU patients.Large sample study is still needed to compare EGDS and STDS with BIS.

Objective To investigate the risk factors and prevention of the ERCP-related upper gastrointestinal bleeding in patients with choledocholithiasis.Methods The clinical data of 678 patients who received ERCP in Yijishan Hospital of Wannan Medical College between January 2014 and December 2014 were reviewed.Univariate and multivariate analyses were performed to define the independent risk factor(s) for delayed hemorrhage following ERCP.Results A total of 383 patients,in whom 157 were males and 226 were females,the age ranged from 19 to 88 years,were recruited to the study.ERCP-related upper gastrointestinal bleeding occurred in 41 patients(10.7％),intraoperative bleeding occurred in 27(7.0％) and postoperative hemorrhage in 14 (3.7％).Twenty-eight cases were mild bleeding,9 moderate (4 caused by laceration of the cardiac mucosa) and 4 were severe bleeding.All patients recovered and were discharged,and no death occurred.No single case required surgical conversion.Univariate analysis revealed that cholangitis,medical history of aspirin/clopidogrel,giant diverticulum and the major papilla inside the diverticulum were risk factors for delayed hemorrhage following ERCP (P ＜ 0.05).Multivariate analysis indicated that independent risk factors were associated with cholangitis (OR =4.125,95％ CI:1.306-13.031,P ＜ 0.05),medical history of aspirin/clopidogrel (OR =10.220,95％ CI:2.997-34.853,P ＜ 0.01) and major papilla occurred inside the diverticulum(OR =14.064,95％ CI:1.888-104.762,P ＜ 0.05).Conclusion Cholangitis,medical history of aspirin/clopidogrel and major papilla at the diverticulum may increase the risks for upper gastrointestinal bleeding in ERCP in patients with choledocholithiasis.However,the hemorrhage should be actively managed,especially in endoscopy,once the bleeding occurs.

Objective:To investigate the incidence of cervical metastasis of oral and maxillary squamous cell carcinoma(SCC)and to define its impact factors.Methods:A retrospective study of patients with SCC of hard palate and maxillary alveolus treated by surgery from 2002 to 2011.Results:The incidences of cervical metastasis and occult metastasis were 17.2%(11 /64)and 9.8%(5 /51)re-spectively.pT classification and vascular invasion were correlated with cervical metastasis.Occult metastatic risk was significantly higher in pT4 patients.Presence of positive nodes impaired prognosis significantly.Conclusion:Overall and occult metastasis of oral and maxillary SCC were highly associated with pT classification.Routine and synchronous elective neck dissection(END)is recomend for the treatment of T4 lesions while observation is alternative for T1 -T3 lesions.

OBJECTIVETo study the clinic presentation, radiology, pathology of recurrent ameloblastoma (RAB).

METHODSAll RAB cases accepted treatment in School of Stomatology of Nanjing University during 1996.1-2008.3 were retrospected. The clinic presentation, the radiological classification and pathological classification were summarized and analyzed.

RESULTSThere were 23 RAB patients during 1996.1-2008.3. 3 patients recurred twice, 20 patients recurred once, and 26 cases were found together. 19 patients were performed conservative surgery while 4 patients were performed radical surgery in the primary treatment; 4 patients were performed conservative surgery and 19 patients were performed radical surgery in the recurrence. The radiological classification included 12 cases multicystic, 6 cases unicystic, and 8 cases extraosseous. The pathological classification included 21 cases follicular ameloblastoma, and 5 cases plexiform ameloblastoma. The multicystic after conservative surgery (11 cases) and extraosseous ameloblastoma after radical treatment (8 cases) were more than others according the radiological classification and treatment.

CONCLUSIONConservative surgery has apparent higher recurrences rate than radical surgery. The follicular ameloblastoma has more aggressive biological behave and is more liable to recurred.

Adult ; Ameloblastoma ; Female ; Humans ; Male ; Neoplasm Recurrence, Local ; Oral Medicine