Ascorbate peroxidase catalyses synthesis of protocatechualdehyde from p-hydroxybenzaldehyde in Lycoris aurea.

Protocatechualdehyde is a plant natural phenolic aldehyde and an active ingredient with important bioactivities in traditional Chinese medicine. Protocatechualdehyde is also a key intermediate in the synthesis of Amaryllidaceae alkaloids for supplying the C6-C1 skeleton. However, the biosynthesis of protocatechualdehyde in plants remains obscure. In this study, we measured the protocatechualdehyde contents in the root, bulb, scape and flower of the Amaryllidaceae plant Lycoris aurea (L'Hér.) Herb., and performed the correlation analysis between the protocatechualdehyde contents and the transcriptional levels of the phenolic oxidization candidate protein encoding genes. We found that a novel ascorbate peroxidase encoded by the contig_24999 in the L. aurea transcriptome database had potential role in the biosynthesis of protocatechualdehyde. The LauAPX_24999 gene was then cloned from the cDNA of the scape of L. aurea. The transient expression of LauAPX_24999 protein in Arabidopsis protoplasts demonstrated that LauAPX_24999 protein was localized in the cytoplasm, thus belonging to Class II L-ascorbate peroxidase. Subsequently, LauAPX_24999 protein was heterogenously expressed in Escherichia coli, and identified that LauAPX_24999 biosynthesized protocatechualdehyde from p-hydroxybenzaldehyde using L-ascorbic acid as the electron donor. The protein structure modelling and molecular docking indicated that p-hydroxybenzaldehyde could access to the active pocket of LauAPX_24999 protein, and reside at the δ-edge of the heme group while L-ascorbic acid binds at the γ-heme edge. To our knowledge, LauAPX_24999 is the first enzyme discovered in plants able to biosynthesize protocatechualdehyde from p-hydroxybenzaldehyde, and offers a competent enzyme resource for the biosynthesis of Amaryllidaceae alkaloids via synthetic biology.

Effects of blended learning on undergraduate nursing students' knowledge, skills, critical thinking ability and mental health: A systematic review and meta-analysis.

AIM: This study aimed to evaluate the effects of blended learning on nursing students. The primary outcomes include knowledge and skills, and the secondary outcomes include critical thinking ability, mental health, blended learning design, and nursing students' attitudes toward blended learning. BACKGROUND: Blended learning combines the advantages of online learning and traditional face-to-face learning, and makes up for the disadvantages of simple online learning or traditional learning. The effects of blended learning on the knowledge, skills, critical thinking ability, and mental health of nursing students were unknown. DESIGN: Systematic review and meta-analysis. METHODS: The present systematic review and meta-analysis was applied according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Publications were searched in PubMed, Web of Science, EMBASE, ERIC, CINAHL and the Cochrane's Library before February 2023. Two researchers independently retrieved articles and evaluated quality. The meta-analysis was performed using Stata 12.0 software according to PRISMA guidelines. The risk of bias in the selected studies was evaluated using the Revised Cochrane risk-of-bias tool for randomized trials. Heterogeneity was assessed by I2 and P statistics. Standardized mean difference (SMD) and 95% confidence intervals (CIs) were used as effective indicators. RESULTS: A total of 26 studies involving 2823 nursing students were included in the present study. The results showed that blended learning courses were designed based on learning theory. Blended learning was more effective on the knowledge (SMD = 0.73, 95%CI [0.37, 1.09]) and skills (SMD = 0.86, 95% CI [0.35, 1.37]) compared with non-blended learning for nursing students. Critical thinking ability improved significantly through BL (SMD = 2.23, 95% CI [0.85, 3.61]). In addition, blended learning had a positive impact on nursing students' mental health. Nursing students were very satisfied with blended learning. CONCLUSIONS: The results of this study indicated that blended learning had a positive impact on nursing students. In the future, the optimal ratio of online to offline learning in blended learning should also be explored.

Limosilactobacillus reuteri consumption significantly reduces the total cholesterol concentration without affecting other cardiovascular disease risk factors in adults: A systematic review and meta-analysis.

As one of the most significant probiotics, Limosilactobacillus reuteri (L. reuteri) has been exploited as a nutritional supplement. We hypothesized that L. reuteri consumption might improve the significant risk factors of cardiovascular disease, including blood pressure, blood lipid, and blood glucose. However, previous clinical studies have shown controversial results. This study aims to explore the effect of L. reuteri consumption on these risk factors. PubMed, Embase, Scopus, the Cochrane Library, and Web of Science were searched for eligible randomized controlled trials published before May 2022. A total of 6 studies with 4 different L. reuteri strains and including 512 participants were included. The results showed that L. reuteri consumption significantly reduced total cholesterol (TC) by -0.26 mmol/L compared with the control group. In contrast, it did not affect systolic blood pressure, diastolic blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), or triglycerides. Subgroup analysis showed a significant reduction in TC when participants were <55 years old, had a body mass index between 25 and 30, or had hypercholesterolemia. In addition, TC decreased significantly when L. reuteri supplementation was >5 × 109 colony-forming unit or the length of the intervention was <12 weeks. Strain subgroup analysis showed that L. reuteri NCIMB 30242 significantly reduced TC and LDL-C. In conclusion, L. reuteri consumption has a significant TC-lowering effect, which can effectively reduce the risks of cardiovascular disease associated with hypercholesterolemia. However, the results do not support the effectiveness of L. reuteri consumption on other metabolic outcomes. Further examination of larger sample sizes is needed to confirm these findings.

Effect of inorganic nitrate supplementation on blood pressure in older adults: A systematic review and meta-analysis.

BACKGROUND: Previous clinical studies have shown controversial results regarding the effect of inorganic nitrate supplementation on blood pressure (BP) in older individuals. We performed this systematic review and meta-analysis to assess the effect of inorganic nitrate on BP in older adults. METHODS: Eligible studies were searched in Cochrane Library, PubMed, Scopus, Web of Science, and Embase. Randomized controlled trials which evaluated the effect of inorganic nitrate consumption on BP in older adults were recruited. The random-effect model was used to calculate the pooled effect sizes. RESULTS: 22 studies were included in this meta-analysis. Overall, inorganic nitrate consumption significantly reduced systolic blood pressure (SBP) by -3.90 mmHg (95% confidence interval: -5.23 to -2.57; P < 0.001) and diastolic blood pressure (DBP) by -2.62 mmHg (95% confidence interval: -3.86 to -1.37; P < 0.005) comparing with the control group. Subgroup analysis showed that the BP was significantly reduced when participants' age≥65, BMI>30, or baseline BP in prehypertension stage. And both SBP and DBP decreased significantly after acute nitrate supplementation of a single dose (<1 day) or more than 1-week. However, participants with hypertension at baseline were not associated with significant changes in both SBP and DBP. Subgroup analysis of measurement methods showed that only the resting BP group showed a significant reduction in SBP and DBP, compared with the 24-h ambulatory BP monitoring (ABPM) group and daily home BP measurement group. CONCLUSION: These results demonstrate that consuming inorganic nitrate can significantly reduce SBP and DBP in older adults, especially in whose age ≥ 65, BMI＞30, or baseline BP in prehypertension stage.

The Effect of Lactobacillus Consumption on Human Blood Pressure: a Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES: Previous clinical studies have shown controversial results regarding the effect of Lactobacillus supplementation on blood pressure (BP). The purpose of this systematic review and meta-analysis is to examine the effect of Lactobacillus consumption on BP. METHODS: Eligible randomized controlled trials (RCTs) were searched from five electronic databases until May 2020. In total, 18 studies were included in our meta-analysis. Quality of the selected studies was assessed, and a random-effects model was used to calculate the overall effect sizes of weighted mean differences (WMD). This systematic review was registered in PROSPERO with the number: CRD42019139294. RESULTS: Lactobacillus consumption significantly reduced systolic blood pressure (SBP) by -2.74 mmHg (95% confidence interval, -4.96 to -0.51) and diastolic blood pressure (DBP) by -1.50 mmHg (95% confidence interval, -2.44 to -0.56) when comparing with the control group. Subgroup analysis showed that type 2 diabetes mellitus (T2DM) patients, Asian individuals, or borderline hypertension participants were more sensitive to daily consumption of Lactobacillus. And the effect of Lactobacillus on BP-reduction was more significant in capsule form, with the dose was above 5 × 109 colony-forming unit (CFU)/day or lasted for more than 8 weeks. CONCLUSIONS: Our present study suggests that Lactobacillus consumption in capsule form when the daily dose is above 5 × 109 CFU for more than 8 weeks can decrease SBP or DBP in T2DM patients, borderline hypertension participants or Asian individuals.

High salt diet elevates the mean arterial pressure of SLC14α1 gene depletion mice.

AIMS: Urea transporter B (UTB) is encoded by the SLC14α1 gene, and exerts its activity in the choroid plexus (CP) by regulating [Na+] in the cerebrospinal fluid (CSF) and maintaining normal blood pressure in mice fed on high salt diet. The aim of this study is to investigate the effect of high salt diet on the mean arterial pressure (MAP) in SLC14α1 depletion mice and its possible molecular mechanism. MAIN METHODS: Adult male mice were divided into four groups: 1) UTB+/+(wild type) mice + normal salt diet (0.3% NaCl, NS); 2) UTB+/+ mice + high salt diet (8% NaCl, HS); 3) UTB-/- (SLC14α1 knockout) mice + NS; 4) UTB-/- mice + HS, each group consisted of 6 mice. The MAP of mice was measured by non-invasive detection method after HS diet for 4 weeks, followed by euthanization for brain and blood collection. KEY FINDINGS: HS significantly elevated the MAP and CSF [Na+] in UTB-/- mice in comparison with wild type mice; however, NS didn't alter the MAP and CSF [Na+] in either wild type mice or UTB-/- mice. HS also induced the expression of ENaC-α and α1-Na+-K+-ATPase in UTB-/- mice as confirmed by RT-PCR and Western blot. SIGNIFICANCE: These results suggest that the depletion of SLC14α1 gene in mice may contribute to the HS-induced abnormality of sodium transportation in the CSF, and lead to the elevation of MAP, which eventually promote the development of salt-sensitive hypertension.

Removal of selenate from brine using anaerobic bacteria and zero valent iron.

The mining industry needs to treat large volumes of wastewater highly concentrated in chemical compounds that can adversely affect receiving environments. One promising method of treatment is the use of reverse osmosis to remove most of the dissolved salts. However, the resulting brine reject is a highly saline wastewater that needs further treatment to remove the toxic components, such as selenate, which is a chemical compound of great concern in coal-mining regions. Biological reduction and removal of dissolved selenium from a brine solution was achieved. Microorganisms were enriched from environmental samples collected from two mines, respectively, at different geographic locations through adaptive evolution in the laboratory. Batch treatment of typical brine was tested with two different enrichments with the addition of either of two chemical forms of iron, ferrous chloride or zero valent iron. Successful selenium removal in the presence of high nitrate and sulphate concentrations was achieved with a combination of enriched microorganisms from one particular site and the addition of zero-valent iron. The composition and metabolic potential of the enriched microorganisms revealed Clostridium, Sphaerochaeta, Synergistes and Desulfosporosinus species with the metabolic potential for selenate reduction through the YgfK enzymatic process associated with selenium detoxification.