Enhancing levan biosynthesis by destroying the strongly acidic environment caused by membrane-bound glucose dehydrogenase (mGDH) in Gluconobacter sp. MP2116.

Levan produced by Gluconobacter spp. has great potential in biotechnological applications. However, Gluconobacter spp. can synthesize organic acids during fermentation, resulting in environmental acidification. Few studies have focused on the effects of environmental acidification on levan synthesis. This study revealed that the organic acids, mainly gluconic acid (GA) and 2-keto-gluconic acid (2KGA) secreted by Gluconobacter sp. MP2116 created a highly acidic environment (pH < 3) that inhibited levan biosynthesis. The levansucrase derived from strain MP2116 had high enzyme activity at pH 4.0 âˆ¼ pH 6.5. When the ambient pH was less than 3, the enzyme activity decreased by 67 %. Knocking out the mgdh gene of membrane-bound glucose dehydrogenase (mGDH) in the GA and 2KGA synthesis pathway in strain MP2116 eliminated the inhibitory effect of high acid levels on levansucrase function. As a result, the levan yield increased from 7.4 g/l (wild-type) to 18.8 g/l (Δmgdh) during fermentation without pH control. This study provides a new strategy for improving levan production by preventing the inhibition of polysaccharide synthesis by environmental acidification.

A strategy to reduce the byproduct glucose by simultaneously producing levan and single cell oil using an engineered Yarrowia lipolytica strain displaying levansucrase on the surface.

Currently, levan is attracting attention due to its promising applications in the food and biomedical fields. Levansucrase synthesizes levan by polymerizing the fructosyl unit in sucrose. However, a large amount of the byproduct glucose is produced during this process. In this paper, an engineered oleaginous yeast (Yarrowia lipolytica) strain was constructed using a surface display plasmid containing the LevS gene of Gluconobacter sp. MP2116. The levansucrase activity of the engineered yeast strain reached 327.8 U/g of cell dry weight. The maximal levan concentration (58.9 g/l) was achieved within 156 h in the 5-liter fermentation. Over 81.2 % of the sucrose was enzymolyzed by the levansucrase, and the byproduct glucose was converted to 21.8 g/l biomass with an intracellular oil content of 25.5 % (w/w). The obtained oil was comprised of 91.3 % long-chain fatty acids (C16-C18). This study provides new insight for levan production and comprehensive utilization of the byproduct in levan biosynthesis.

Effect of Preoperative Nutritional Status on Postoperative Functional Recovery of Hip Joint in Elderly Patients with Intertrochanteric Fractures.

Objective: The state of nutrition of senior patients with intertrochanteric fracture of femur before operation affects the patients' tolerance to the operation,the body recovery, healing of the wound and clinical prognosis. For these patients, the poor state of nutrition may lengthen the time of being in hospital, leading to poor hip recovery and clinical outcome. But currently, the relationship between functional recovery of hip joint after operation of intertrochanteric fracture in elderly patients and camp condition has not been reported. To investigate the effect of preoperative nutritional status on postoperative recovery of hip joint function in elderly patients with intertrochanteric fractures. Methods: Retrospective analysis was performed on the data of 96 elderly patients with intertrochanteric fracture of the femur treated with closed reduction PFNAfrom January 2021 to January 2022 in Dongying People's Hospital Trauma Orthopedics Department. There were 36 male patients and 60 female patients aged from 65 to 92.The patients were divided into the normal nutrition group (GNRI ≥ 92, n = 46) and the malnutrition group (GNRI < 92, n = 50). The general clinical data, time from injury to operation, intraoperative and postoperative allogeneic blood transfusion rate, postoperative complication rate, postoperative mortality 1 year, and Harris hip function score at 3, 6, 9 months and the last follow-up were compared between the two groups. Results: All patients were followed up for 9 to 15 months(mean,13.9 months) after surgery. The preoperative hemoglobin levels in the normal and malnutrition groups were 8.6-13.2 and 7.4-11.2 g/dL, respectively (P < .05). The time from injury to surgery in the normal nutrition group was significantly shorter than that in the malnutrition group (P < .01). The preoperative hemoglobin level in the normal nutrition group was significantly higher than that in the malnutrition group. The time from injury to operation in normal nutrition group and malnutrition group are respectively (1.1-5.2), (4.3-6.6)d; the intraoperative and postoperative allogeneic blood transfusion rates are respectively 47.8%(22/46), 92%(46/50);the incidence of postoperative complications are respectively 6.52%(3/46), 32%(16/50); the mortality rates within 1 year after operation are respectively 2.17%(1/46), 12%(6/50). In contrast, the postoperative allogeneic blood transfusion, postoperative complication, and postoperative complication rates in the normal nutrition group were significantly lower than those in the malnutrition group (P < .05). 3 months after surgery, the Harris hip function scores of patients in normal nutrition group and malnutrition group are respectively (75.26±4.02), (64.28±3.82); 6 months after surgery, the Harris hip function scores of them are respectively (80.42±3.86), (70.14±5.06).During the last follow-up, scores are (82.23±2.98), (72.12±4.62). At the 3, 6, and last follow-up after surgery, the Harris hip function score in the normal nutrition group was significantly higher than in the malnutrition group (P < .05). Conclusion: Preoperative malnutrition in elderly patients with intertrochanteric fracture has adverse effects on postoperative hip function recovery, and 1-year postoperative survival rate.GNRI can be used for simple screening. Early assessment of patients' nutritional status.

The Roles of Cultural Capital in Teacher-Student Interactions in China: A Qualitative Study of Students in Higher Vocational Colleges.

The theory of cultural capital has long been applied to explain academic achievement. This qualitative study investigated first-year students in higher vocational colleges and, taking this low cultural capital group as an example, explored how cultural capital has affected their past teacher-student interactions. Participants described their experience of interacting with their teachers. We found that these students primarily experienced authoritative and laissez-faire teacher-student interactions. Students' embodied and institutionalized cultural capital profoundly affected different aspects of the teacher-student interaction. In modern China, vocational and academic education are of the same status, so teachers should modify their evaluations based solely on academic achievement. When interacting with students, teachers should be more understanding and interact in a more student-centred way. Teacher training programmes should also be reformed, and training for teachers in general and vocational schools should be distinguished.

Efficacy of resveratrol supplementation on liver enzymes in patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis.

OBJECTIVE: Randomized clinical trials (RCTs) examining the effects of resveratrol supplementation on liver enzymes in non-alcoholic fatty liver disease (NAFLD) have reported conflicting results. The aim of this systematic review was to summarize evidence of the effects of resveratrol supplementation on alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in patients with NAFLD by performing a meta-analysis of RCTs. METHODS: PubMed, Cochrane Library, Scopus, and Web of Science databases were electronically explored from inception to August 2020 for all relevant studies. Random effect models were used to estimate liver enzymes changes between resveratrol supplementation and control groups by evaluating the weighted mean differences (WMD) with 95 % confidence intervals (CIs). RESULTS: Five trials with a total of 216 patients were included in the meta-analysis. The pooled results showed that resveratrol supplementation did not result in significant changes in serum ALT (WMD= -2.48 IU/L; 95 % CI: -12.30, 7.34; P = 0.62), and AST (WMD = -2.90 IU/L; 95 % CI: -9.77, 3.98; P = 0.40) concentrations. Subgroup analysis revealed a significant reduction in serum ALT and AST concentrations in the participants with mean age <45 years, and studies with intervention dosage <1000 mg/day. In addition, ALT and AST levels were decreased significantly in studies with duration >12 weeks and participants with BMI < 30 kg/m2, respectively. CONCLUSIONS: The overall results indicated that resveratrol supplementation did not affect liver enzymes in patients with NAFLD. More studies examining the effect of resveratrol supplementation on liver enzymes are needed in the future.

The association between the phenotype of excessive daytime sleepiness and blood pressure in patients with obstructive sleep apnea-hypopnea syndrome.

OBJECTIVE: Investigate the clinical features and the blood pressure (BP) pattern of the phenotype of excessive daytime sleepiness (EDS) in OSAHS. METHODS: A total of 508 Chinese adults with suspected OSAHS were referred to our sleep laboratory from October 2009 to May 2012. On the same night of polysomnography (PSG), the levels of blood pressure were measured before sleeping (bedtime BP) and immediately after waking up in the next morning (morning BP). EDS was recognized as Epworth Sleepiness Scale (ESS)≥9. Subjects were classified into four groups based on the apnea-hypopnea index (AHI) from PSG as follows: control (simple snoring) group (control, n=104) with AHI<5; mild group (mild, n=89) with AHI≥5 and <15; moderate group (moderate, n=70) with AHI≥15 and<30; and severe group (severe, n=245) with AHI ≥30. The differences and correlations between BP and PSG parameters in EDS and non-EDS group of OSAHS patients were analyzed. RESULTS: In all subjects, ESS was positively correlated with morning diastolic blood pressure (DBP), Mean arterial pressure (MAP) and bedtime DBP (r=0.144, 0.102 and 0.114, respectively, each P value<0.05). In OSAHS patients, ESS was only positively correlated with morning DBP (r=0.137, P<0.05). OSAHS patients with EDS phenotype were younger and were more likely to have the symptom of waking up feeling tired (36.1% vs. 23.2%, p=0.023), who had lower MSaO2, longer SIT90 (the ratio of time of SpO2 below 90% in total sleep time) and higher DBP (bedtime as well as morning). In patients with AHI≥15, ESS was correlated positively with both bedtime and morning DBP after controlling the confounding effects of age, sex, BMI, AHI and nadir nocturnal oxygen saturation( r=0.126,0.143, respectively, both P values<0.05). And in OSAHS patients of EDS phenotype, the bedtime DBP, bedtime MAP, morning DBP, and morning MAP were 3~5 mm Hg higher than that in patients of non-EDS phenotype(P<0.05). In the moderate and severe OSAHS group, patients with EDS phenotype were younger and had a lower mean blood oxygen saturation (MSaO2), longer time of SpO2 below 90% and higher SIT90 than patients with non-EDS phenotype (P<0.05). In hypertensive OSAHS patients, patients with EDS were also younger and had higher micro-arousal index (MiI), as well as higher morning DBP, morning MAP and bedtime DBP than that in non-EDS group (P<0.05). CONCLUSIONS: EDS in OSAHS patients is a special phenotype, which was characterized by younger age, higher DBP and more severe hypoxic load. This feature is mainly manifested in moderate and severe OSAHS patients. It is very important to identify the phenotype of EDS in patients with OSAHS, who may meet more benefits from effective treatment of OSAHS by correcting the intermittent nocturnal hypoxia and sleep fragmentation.

[Application of Berlin questionnaire in the screening of obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To investigate the value of Berlin questionnaire in screening obstructive sleep apnea hypopnea syndrome (OSAHS) among Chinese. METHODS: A total of 302 cases with suspected OSAHS were referred to our sleep laboratory. The Berlin questionnaire scores and polysomnography (PSG) monitoring data were analyzed. According to the Berlin questionnaire score, the patients were divided into high and lower risk groups for OSAHS. In terms of the PSG monitoring results, the patients were classified into non-OSAHS, mild, moderate and severe OSAHS groups. The age, gender, apnea hypopnea index (AHI), body mass index, and the Berlin questionnaire (BQ) result were compared among the 4 groups. The correlation of Berlin questionnaire result with age, AHI, the lowest SpO2 (LSpO2) and microarousal index (MAI) were analyzed. RESULTS: There were significant differences in the Berlin questionnaire results among non-OSAHS and the other 3 groups (χ(2) = 13.961, 8.466, 42.156, P < 0.0083); and between the severe OSAHS and the other 2 groups (χ(2) = 9.439, 11.162, P < 0.0083). There was no statistical difference between the mild and moderate groups (P > 0.0083). The ratio of the high BQ risk patients had an increasing tendency as the severity of OSAHS was increased (χ(2) = 34.211, P < 0.01). The Berlin questionnaire results showed a positive correlation with age, AHI or MAI (r = 0.125, 0.346, 0.198, all P < 0.05, respectively) but a negative correlation with LSpO2 (r = -0.371, P < 0.01). The Berlin questionnaire results showed no correlation with gender (P > 0.05). The sensitivity and the specificity of the Berlin questionnaire in predicting sleep apnea were 0.71 and 0.72, respectively. CONCLUSIONS: With the moderate sensitivity and the specificity, the Berlin questionnaire has some value in screening patients with OSAHS. However, it is not correlated with the severity of OSAHS in Chinese patients. Thus Berlin questionnaire has limited value in the screening of OSAHS among Chinese.