Prevalence and risk factors of sub-health and circadian rhythm disorder of cortisol, melatonin, and temperature among Chinese midwives.

Objective: This study aimed to explore the influencing factors of sub-health and circadian rhythm disorder among midwives and whether circadian rhythm disorder was associated with sub-health. Methods: A multi-center cross-sectional study was conducted among 91 Chinese midwives from six hospitals through cluster sampling. Data were collected by demographic questionnaire, Sub-Health Measurement Scale version 1.0, and circadian rhythm detection. Minnesota single and population mean cosine methods were used to analyze the rhythm of cortisol, melatonin, and temperature. Binary logistic regression, nomograph model, and forest plot were performed to identify variables associated with midwives' sub-health. Results: There were 65 midwives with sub-health and 61, 78, and 48 midwives with non-validation of circadian rhythms of cortisol, melatonin, and temperature among 91 midwives, respectively. Midwives' sub-health was significantly related to age, duration of exercise, weekly working hours, job satisfaction, cortisol rhythm, and melatonin rhythm. Based on these six factors, the nomogram was presented with significant predictive performance for sub-health. Furthermore, cortisol rhythm was significantly associated with physical, mental, and social sub-health, whereas melatonin rhythm was significantly correlated with physical sub-health. Conclusion: Sub-health and circadian rhythm disorder were generally common among midwives. Nurse administrators are supposed to pay attention and take measures to prevent sub-health and circadian rhythm disorder among midwives.

Neuroglobin Facilitates Neuronal Oxygenation through Tropic Migration under Hypoxia or Anemia in Rat: How Does the Brain Breathe?

The discovery of neuroglobin (Ngb), a brain- or neuron-specific member of the hemoglobin family, has revolutionized our understanding of brain oxygen metabolism. Currently, how Ngb plays such a role remains far from clear. Here, we report a novel mechanism by which Ngb might facilitate neuronal oxygenation upon hypoxia or anemia. We found that Ngb was present in, co-localized to, and co-migrated with mitochondria in the cell body and neurites of neurons. Hypoxia induced a sudden and prominent migration of Ngb towards the cytoplasmic membrane (CM) or cell surface in living neurons, and this was accompanied by the mitochondria. In vivo, hypotonic and anemic hypoxia induced a reversible Ngb migration toward the CM in cerebral cortical neurons in rat brains but did not alter the expression level of Ngb or its cytoplasm/mitochondria ratio. Knock-down of Ngb by RNA interference significantly diminished respiratory succinate dehydrogenase (SDH) and ATPase activity in neuronal N2a cells. Over-expression of Ngb enhanced SDH activity in N2a cells upon hypoxia. Mutation of Ngb at its oxygen-binding site (His64) significantly increased SDH activity and reduced ATPase activity in N2a cells. Taken together, Ngb was physically and functionally linked to mitochondria. In response to an insufficient oxygen supply, Ngb migrated towards the source of oxygen to facilitate neuronal oxygenation. This novel mechanism of neuronal respiration provides new insights into the understanding and treatment of neurological diseases such as stroke and Alzheimer's disease and diseases that cause hypoxia in the brain such as anemia.

Mediating effect of resilience between social support and compassion fatigue among intern nursing and midwifery students during COVID-19: a cross-sectional study.

AIMS: To examine the mediating effect of resilience between social support and compassion fatigue among intern nursing and midwifery students during COVID-19. BACKGROUND: Compassion fatigue has become exceedingly common among intern nursing and midwifery students, especially during the COVID-19 pandemic. Social support and resilience can help intern nursing and midwifery students control their negative emotions, reduce compassion fatigue, and increase their well-being. However, the mediating effect of resilience between social support and compassion fatigue remains unclear. DESIGN: A multicentre cross-sectional survey. METHODS: A total of 307 intern nursing and midwifery students were recruited from November 2020 to February 2021 in tertiary grade A hospitals in China. Structural equation modelling was applied to analyse the mediating effects of resilience between social support and compassion fatigue. The Social Support Rating Scale, the 10-item Connor-Davidson Resilience Scale, and the Chinese version of the Compassion Fatigue Short Scale were used to collect data. The hypothetical path model was tested by using IBM SPSS version 26.0 and AMOS version 26.0 software. RESULTS: Intern nursing and midwifery students had moderate compassion fatigue. Social support positively affected resilience (ß = 0.514, p < 0.01). Social support negatively affected compassion fatigue (ß = - 0.310, p < 0.01), while resilience negatively affected compassion fatigue (ß = - 0.283, p < 0.01). Resilience played a mediating role between social support and compassion fatigue. CONCLUSION: Social support can directly affect the compassion fatigue of intern nursing and midwifery students during COVID-19 and indirectly through resilience. Stronger resilience can reduce compassion fatigue. Accordingly, resilience-based interventions should be developed to reduce compassion fatigue.

KMT2E Haploinsufficiency Manifests Autism-Like Behaviors and Amygdala Neuronal Development Dysfunction in Mice.

Autism spectrum disorders (ASD) are highly heterogeneous neurodevelopmental disorders characterized by impaired social interaction skills. Whole exome sequencing has identified loss-of-function mutations in lysine methyltransferase 2E (KMT2E, also named MLL5) in ASD patients and it is listed as an ASD high-risk gene in humans. However, experimental evidence of KMT2E in association with ASD-like manifestations or neuronal function is still missing. Relying on KMT2E+/- mice, through animal behavior analyses, positron emission tomography (PET) imaging, and neuronal morphological analyses, we explored the role of KMT2E haploinsufficiency in ASD-like symptoms. Behavioral results revealed that KMT2E haploinsufficiency was sufficient to produce social deficit, accompanied by anxiety in mice. Whole-brain 18F-FDG-PET analysis identified that relative amygdala glycometabolism was selectively decreased in KMT2E+/- mice compared to wild-type mice. The numbers and soma sizes of amygdala neurons in KMT2E+/- mice were prominently increased. Additionally, KMT2E mRNA levels in human amygdala were significantly decreased after birth during brain development. Our findings support a causative role of KMT2E in ASD development and suggest that amygdala neuronal development abnormality is likely a major underlying mechanism.

An approach of multi-element fusion method for harmful algal blooms prediction.

The harmful algal blooms (HABs) are an issue of concern for water management worldwide. Effective strategies for monitoring and predicting of HAB spatio-temporal variability in waterbodies are more essential. To promote the monitoring and predicting of HABs, we proposed a multi-element fusion prediction (MEFP) method for cyanobacteria bloom. Considering the impact of surrounding factors for HAB occurrence, the proposed MEFP fuses multiple exogenous factors to enhance the prediction accuracy in different environments. Specifically, MEFP adopts a dual-sides network that parallelly captures the potential outbreak patterns on the numerous input features. The restricted Boltzmann machine is utilized to optimize the processing of parameter initialization. Subsequently, the attention mechanism is introduced in the post-network stage to establish the contextual relationship between the current and historical temporal information. The experimental results on the real-world dataset demonstrate the proposed MEFP model outperforms other benchmark methods.

Corrigendum: Comparison of clinical safety and feasibility between reduced-port laparoscopic radical gastrectomy and conventional laparoscopic radical gastrectomy: A retrospective study.

[This corrects the article DOI: 10.3389/fsurg.2022.995194.].

Comparison of clinical safety and feasibility between reduced-port laparoscopic radical gastrectomy and conventional laparoscopic radical gastrectomy: A retrospective study.

Background: Traditional open gastric cancer surgery has evolved from porous to reduced-hole, single-hole, or even natural cavity surgery to laparoscopic surgery, due to the continuous development of minimally invasive concepts and medical technologies, as well as awareness for the concept of rapid recovery. Conventional laparoscopic radical gastrectomy is quite mature in age at the moment, but how to progress to minimally invasive surgery without increasing the difficulty of surgery while ensuring clinical safety and feasibility is worth further investigation. Therefore, the clinical safety and feasibility of reduced port laparoscopic radical gastrectomy were assessed in this study. Methods: Information on the clinical data of patients undergoing laparoscopic radical gastric cancer surgery in a single centre between May 2020 and May 2022 was collected, and a total of 232 patients were included in this study according to the study protocol design. The clinical data of 232 patients with gastric cancer treated by two different surgical methods, namely, reduced port laparoscopic surgery (RPLS) or conventional laparoscopic surgery (CLS), were retrospectively analysed. The intraoperative indices, postoperative pathological indices, and short-term postoperative complications (within 30 days) of the two different surgical methods were evaluated, as well as the surgical methods' feasibility and short-term postoperative recovery effect. Results: There was no significant difference between the general data of patients with RPLS and CLS (P > 0.05). Compared with CLSG, the operation time, digestive tract reconstruction time and lymph node dissection time of RPLSG are shorter. The intraoperative blood loss was less, and the incision was minimally invasive (P < 0.05). In the short-term postoperative effect, the level of white blood cell count on the first day, the time of getting out of bed, the time of removing drainage tube, the time of hospitalization and the VAS of pain on the first, third and fifth days after operation, RPLSG was obviously superior to CLSG (P < 0.05). There was no significant difference between RPLSG and CLSG in terms of pathological indices (P > 0.05). Conclusions: The treatment of gastric cancer with RPLS has good safety, feasibility and short-term postoperative effects, which is in line with the implementation of the modern concept of rapid rehabilitation surgery.

A quantitative model based on gross tumor volume of gastric adenocarcinoma corresponding to N-stage measured at multidetector computed tomography for preoperative determination of resectability: A case control study.

Purpose: To develop and validate a quantitative model based on gross tumor volume (GTV) of gastric adenocarcinoma (GA) corresponding to N-stage measured at multidetector computed tomography (CT) for preoperative determination of resectability. Materials and methods: 493 consecutive patients with confirmed GA undergoing contrast-enhanced CT two weeks before treatments were randomly enrolled into the training cohort (TC, n = 271), internal validation cohort (IVC, n = 107) and external validation cohort (EVC, n = 115). GTV was measured on CT by multiplying sums of all tumor areas by section thickness. In TC, univariate and multivariate analyses were performed to select factors associated with resectability. Receiver operating characteristic (ROC) analysis was to determine if N-stage based GTV could identify resectability. In IVC and EVC, unweighted Cohen's Kappa tests were to evaluate performances of the ROC models. Results: According to univariate analysis, age, cT stage, cN stage and GTV were related to resectability in TC (all P-values < 0.05), and multivariate analysis suggested that cN stage and GTV were independent risk factors with odds ratios of 1.594 (95% confidence interval [CI]: 1.105-2.301) and 1.055 (95%CI: 1.035-1.076), respectively. ROC analysis in TC revealed the cutoffs of 21.81, 21.70 and 36.93 cm3 to differentiate between resectable and unresectable cancers in stages cN0-3, cN2 and cN3 with areas under the curves of more than 0.8, respectively, which was validated in IVC and EVC with average Cohen k-values of more than 0.72. Conclusions: GTV and cN stage can be independent risk factors of unresectable GA, and N-stage based GTV can help determine resectability.

The association between circadian rhythm of cortisol and shift work regularity among midwives-A multicenter study in Southeast China.

Objective: This article aims to explore the association between the trends of cortisol rhythm and the regularity of shift work among midwives. Methods: Midwives from six Southeast Chinese hospitals were recruited through cluster sampling in a multi-center cross-sectional study. Urine samples were collected half an hour after waking up, at 11:00, 19:00, and 23:00 on two consecutive days in a longitudinal cohort. The urinary cortisol was assayed by the chemiluminescence method. Results: A total of 86 midwives were included in this study, contributing 688 cortisol samples. The midwives displayed a circadian rhythm in cortisol secretion, with zeniths in the morning and nadirs in the evening. The trend of the first day was repeated on the second day. Although the total working hours per week of the two groups, namely the regular shift group (N = 43) and the irregular shift group (N = 43), were the same, significant main effects of groups (F = 62.569, p < 0.001), time (F = 45.304, p < 0.001), and group-by-time interaction (F = 226.695, p < 0.001) were indicated through linear mixed models. The main effect of day was not statistically significant, with F = 0.105 and p = 0.746. The fluctuation range of cortisol curve in the group with irregular schedules was slightly lower than that in the group with regular schedules. Conclusion: Our results may indicate that cortisol was more inhibited in midwives with irregular shift patterns than those with regular shift patterns. It is necessary to further study the relationship between cortisol rhythm and patterns of midwives' shifts in future so as to lay a foundation for hospital managers to develop a more reasonable scheduling system for midwives with the further purpose to minimize their occupational fatigue and ensure the safety of mothers and infants.

Enhanced Effects of Iron on Mycelial Growth, Metabolism and In Vitro Antioxidant Activity of Polysaccharides from Lentinula edodes.

The polysaccharides found in Lentinula edodes have a variety of medicinal properties, such as anti-tumor and anti-viral effects, but their content in L. edodes sporophores is very low. In this study, Fe2+ was added to the liquid fermentation medium of L. edodes to analyze its effects on mycelial growth, polysaccharide and enzyme production, gene expression, and the activities of enzymes involved in polysaccharide biosynthesis, and in vitro antioxidation of polysaccharides. The results showed that when 200 mg/L of Fe2+ was added, with 7 days of shaking at 150 rpm and 3 days of static culture, the biomass reached its highest value (0.28 mg/50 mL) 50 days after the addition of Fe2+. Besides, Fe2+ addition also enhanced intracellular polysaccharide (IPS) and exopolysaccharide (EPS) productions, the levels of which were 2.98- and 1.79-fold higher than the control. The activities of the enzymes involved in polysaccharides biosynthesis, including phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), and UDPG-pyrophosphorylase (UGP) were also increased under Fe2+ addition. Maximum PGI activity reached 1525.20 U/mg 30 days after Fe2+ addition, whereas PGM and UGP activities reached 3607.05 U/mg and 3823.27 U/mg 60 days after Fe2+ addition, respectively. The Pearson correlation coefficient showed a strong correlation (p < 0.01) between IPS production and PGM and UGP activities. The corresponding coding genes of the three enzymes were also upregulated. When evaluating the in vitro antioxidant activities of polysaccharides, EPS from all Fe2+-treated cultures exhibited significantly better capacity (p < 0.05) for scavenging -OH radicals. The results of the two-way ANOVA indicated that the abilities of polysaccharides to scavenge O2- radicals were significantly (p < 0.01) affected by Fe2+ concentration and incubation time. These results indicated that the addition of iron provided a good way to achieve desirable biomass, polysaccharide production, and the in vitro antioxidation of polysaccharides from L. edodes.

Exploration of Predictive Biomarkers for Postoperative Recurrence in Chronic Rhinosinusitis with Nasal Polyps Based on Serum Multiple-Cytokine Profiling.

Background: Functional nasal endoscopic surgery (FESS) is an effective treatment approach for chronic rhinosinusitis with nasal polyps (CRSwNP) patients, but some patients still suffer from postoperative recurrence. This study is aimed at investigating the expression of multiple cytokines in CRSwNP and revealing their relationships with postoperative recurrence. Methods: A total of 72 patients with CRSwNP, including 36 primary and 36 recurrent patients, were enrolled. Serum samples were obtained, 30 cytokine levels were measured by multiplex analysis, and the association between cytokine levels and recurrence was assessed. The most potential cytokines were further validated in another independent cohort with 60 primary and 60 recurrent CRSwNP patients. Results: The results of multiple cytokine profiling exhibited that the levels of eotaxin, G-CSF, IFN-α, IL-13, IL-17A, IL-5, MCP-1, and RANTES were vastly changed in the recurrent group in comparison with the primary group. Receiver-operating characteristic (ROC) curves highlighted that serum levels of eotaxin, IL-17A, and RANTES were strongly predictive of postoperative recurrence (area under the curve (AUC) > 0.7, P < 0.05). Further validation results showed that elevated serum eotaxin, IL-17A, and RANTES levels were enhanced in the recurrent group. The ROC curve showed that serum eotaxin (AUC = 0.729, P < 0.001) and RANTES (AUC = 0.776, P < 0.001) exhibited stronger ability than serum IL-17A (AUC = 0.617, P = 0.027) in predicting CRSwNP recurrence. Conclusion: Our data suggested that serum multiple cytokine profiling was associated with postoperative recurrence of CRSwNP, and eotaxin and RANTES might serve as potential biomarkers for predicting postoperative recurrence. These results might contribute to the understanding of the underlying mechanisms of recurrence and provide novel clues for precision therapy in CRSwNP.

Apparent diffusion coefficient derived from diffusion-weighted imaging to differentiate between tumor, tumor-adjacent and tumor-distant tissues in resectable rectal adenocarcinoma.

PURPOSE: To evaluate feasibility of apparent diffusion coefficient (ADC) at different b-values to differentiate between tumor, tumor-adjacent and tumor-distant tissues in rectal adenocarcinoma (RA). MATERIALS AND METHODS: Seventy consecutive patients with RA undergoing preoperative diffusion-weighted imaging were retrospectively enrolled. ADCs of tumor, proximal tumor-adjacent tissue (PTA) and tumor-distant tissue (PTD), and distal tumor-adjacent tissue (DTA) and tumor-distant tissue (DTD) were calculated with b-values of 0 and 800 sec/mm2, 0 and 1000 sec/mm2, 0 and 1500 sec/mm2, and multiple b-values of 0, 50, 100, 800, 1000 and 1500 sec/mm2. Statistical analysis was performed to determine feasibility of ADC to differentiate between pairwise tissues. RESULTS: Mean ADC of tumor was lower than those of PTA, PTD, DTA and DTD; and mean ADCs of PTA and DTA were lower than those of PTD and DTD at all b-values, respectively (all P-values < 0.001). ADC cut-offs of 1.089 × 10-3 mm2/sec (b = 0, 1000 sec/mm2) or 1.215 × 10-3 mm2/sec (b = 0, 800 sec/mm2), and 1.142 × 10-3 mm2/sec (b = 0, 1000 sec/mm2) or 0.995 × 10-3 mm2/sec (b = 0, 1500 sec/mm2) achieved excellent performance in differentiating tumor from PTA or PTD, and tumor from DTA or DTD (area under receiver operating characteristic curves [AUCs]: 0.813 or 0.952, and 0.970 or 0.996), respectively. ADC cut-offs of 1.625 × 10-3 mm2/sec (b = 0, 800 sec/mm2), and 1.165 × 10-3 mm2/sec (b = 0, 1500 sec/mm2) could differentiate PTA from PTD, and DTA from DTD (AUCs: 0.709 and 0.673), respectively. CONCLUSION: ADC can help differentiate between tumor, tumor-adjacent and tumor-distant tissues in RA.

Total laparoscopic versus laparoscopic-assisted transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II adenocarcinoma of the esophagogastric junction: A retrospective study.

Background: The method of operation and the range of resection for Siewert II adenocarcinoma of the esophagogastric junction (AEG) remain controversial. This study aims to evaluate the safety, feasibility, and short-term postoperative effect of total laparoscopic versus laparoscopic-assisted transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II AEG. Methods: Total laparoscopic or laparoscopic-assisted gastrointestinal reconstruction through abdominal posterior mediastinum was performed in 108 patients with Siewert II AEG from October 2017 to February 2019. This study evaluated the loss of intraoperative blood, the number of lymph nodes, the marginal of the tumor, short-term postoperative complications (within 30 days), the rate of survival at follow-up, and the economic cost, feasibility, and effect of short-term postoperative recovery for patients who received these two operations. Result: There were no significant differences in general data between the total laparoscopic group and the laparoscopic-assisted group (P > 0.05). However, the total laparoscopic group cost more time on the surgical procedure and digestive tract reconstruction, lost less intraoperative blood, and had more mediastinal lymph nodes compared with the laparoscopic-assisted group (P < 0.05). The total laparoscopic group was significantly better than the laparoscopic-assisted group compared with the short-term postoperative recovery indexes, such as the first exhaust time, the first defecation time, the first fluid time, the first semi-fluid diet time, the postoperative hospital stay, and other postoperative recovery indexes (P < 0.05). In addition, there were no significant differences in postoperative complications, postoperative pathological indexes, the recurrence rate, and mortality between the total laparoscopic group and laparoscopic-assisted group (P > 0.05). Conclusions: The safety, feasibility, and short-term effect of total laparoscopic transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II AEG were better than those for the laparoscopic-assisted group.

Adenosine triphosphate-activated prodrug system for on-demand bacterial inactivation and wound disinfection.

The prodrug approach has emerged as a promising solution to combat bacterial resistance and enhance treatment efficacy against bacterial infections. Here, we report an adenosine triphosphate (ATP)-activated prodrug system for on-demand treatment of bacterial infection. The prodrug system benefits from the synergistic action of zeolitic imidazolate framework-8 and polyacrylamide hydrogel microsphere, which simultaneously transports indole-3-acetic acid and horseradish peroxidase in a single carrier while preventing the premature activation of indole-3-acetic acid. The ATP-responsive characteristic of zeolitic imidazolate framework-8 allows the prodrug system to be activated by the ATP secreted by bacteria to generate reactive oxygen species (ROS), displaying exceptional broad-spectrum antimicrobial ability. Upon disruption of the bacterial membrane by ROS, the leaked intracellular ATP from dead bacteria can accelerate the activation of the prodrug system to further enhance antibacterial efficiency. In vivo experiments in a mouse model demonstrates the applicability of the prodrug system for wound disinfection with minimal side effects.

Effect of epigallocatechin gallate on the fermentative and physicochemical properties of fermented milk.

Yogurt, a traditional fermented dairy product, is made with a starter that contains Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. The aim of this study was to investigate the effects of different concentrations of epigallocatechin gallate (EGCG; 0, 0.5, 1.0, 3.0, and 5.0 mg/mL) on the growth, metabolism, and acid production of lactic acid bacteria, as well as the texture, stability, and antioxidant activity of fermented milk (yogurt). The results showed that a low concentration of EGCG had no significant effect on the acid production capacity of the starter or on the water-holding capacity of the yogurt but did increase its viscosity. A high concentration (5.0 mg/mL) of EGCG delayed the acid production rate of the starter and decreased the water-holding capacity, but significantly increased the antioxidant activity of yogurt. The addition of EGCG significantly increased the hardness of yogurt. Therefore, EGCG can improve the texture of fermented milk and enhance its antioxidant activity and stability, thus improving the overall quality of yogurt.

Case report: Novel compound-heterozygous mutations in the TCN2 gene identified in a chinese girl with transcobalamin deficiency.

Transcobalamin (TC) deficiency is a rare autosomal recessive disease characterized by megaloblastic anemia. It is caused by cellular vitamin B12 depletion, which subsequently results in elevated levels of homocysteine and methylmalonic acid. This disease is usually diagnosed by genetic analysis of the TCN2 gene. Here, we described a 2.2-month-old Chinese girl with TC deficiency presenting with diarrhea, fever and poor feeding. Whole-exome sequencing detected a pair of compound-heterozygous mutations in TCN2 gene, c.754-12C>G and c.1031_1032delGA (p.R344Tfs*20). To our knowledge, it is the first time that they were identified and reported in TC deficiency. This study contributes to a better understanding of the TC deficiency, expanding the spectrum of TCN2 mutations in this disorder and also supporting the early diagnosis and proper treatment of similar cases in the future.

A multi-stage heuristic method for service caching and task offloading to improve the cooperation between edge and cloud computing.

Edge-cloud computing has attracted increasing attention recently due to its efficiency on providing services for not only delay-sensitive applications but also resource-intensive requests, by combining low-latency edge resources and abundant cloud resources. A carefully designed strategy of service caching and task offloading helps to improve the user satisfaction and the resource efficiency. Thus, in this article, we focus on joint service caching and task offloading problem in edge-cloud computing environments, to improve the cooperation between edge and cloud resources. First, we formulated the problem into a mix-integer nonlinear programming, which is proofed as NP-hard. Then, we proposed a three-stage heuristic method for solving the problem in polynomial time. In the first stages, our method tried to make full use of abundant cloud resources by pre-offloading as many tasks as possible to the cloud. Our method aimed at making full use of low-latency edge resources by offloading remaining tasks and caching corresponding services on edge resources. In the last stage, our method focused on improving the performance of tasks offloaded to the cloud, by re-offloading some tasks from cloud resources to edge resources. The performance of our method was evaluated by extensive simulated experiments. The results show that our method has up to 155%, 56.1%, and 155% better performance in user satisfaction, resource efficiency, and processing efficiency, respectively, compared with several classical and state-of-the-art task scheduling methods.

Effects of Alkali Stress on the Growth and Menaquinone-7 Metabolism of Bacillus subtilis natto.

Menaquinone-7 (MK-7) is an important vitamin K2, synthesized from the menaquinone parent ring and seven isoprene side chains. Presently, the synthesis of MK-7 stimulated by environmental stress primarily focuses on oxygen stress, while the effect of alkali stress is rarely studied. Therefore, this study researched the effects of alkali stress on the fermentation performance and gene expression of Bacillus subtilis natto. The organism's growth characteristics, biomass, sporogenesis, MK-7 biosynthesis, and gene expression were analyzed. After a pH 8.5 stress adaptation treatment for 0.5 h and subsequent fermentation at pH 8.5, which promoted the growth of the strain and inhibited the spore formation rate. In addition, biomass was significantly increased (P < 0.05). The conversion rate of glycerol to MK-7 was 1.68 times higher than that of the control group, and the yield of MK-7 increased to 2.10 times. Transcriptomic analysis showed that the MK-7 high-yielding strain had enhanced carbon source utilization, increased glycerol and pyruvate metabolism, enhanced the Embden-Meyerhof pathway (EMP), tricarboxylic acid (TCA) circulation flux, and terpenoid biosynthesis pathway, and promoted the accumulation of acetyl-CoA, the side-chain precursor of isoprene. At the same time, the up-regulation of transketolase increased the metabolic flux of the pentose phosphate (HMP) pathway, which was conducive to the accumulation of D-erythrose 4-phosphate, the precursor of the menadione parent ring. This study's results contribute to a better understanding of the effects of environmental stress on MK-7 fermentation by Bacillus subtilis natto and the molecular regulatory mechanism of MK-7 biosynthesis.

Directional-path modification strategy enhances PET hydrolase catalysis of plastic degradation.

Poly (ethylene terephthalate) (PET) is a widely used type of general plastic that produces a significant amount of waste due to its non-degradable properties. We propose a novel directional-path modification (DPM) strategy, involving positive charge amino acid introduction and binding groove remodeling, and apply it to Thermobifida fusca cutinase to enhance PET degradation. The highest value of PET degradation (90%) was achieved in variant 4Mz (H184S/Q92G/F209I/I213K), exhibiting values almost 30-fold that of the wild-type. We employed molecular docking, molecular dynamics simulations, and QM/MM MD for the degradation process of PET, accompanied by acylation and deacylation. We found that the distance of nucleophilic attack was reduced from about 4.6 Å in the wild type to 3.8 Å in 4Mz, and the free energy barrier of 4Mz dropped from 14.3 kcal/mol to 7.1 kcal/mol at the acylation which was the rate-limiting step. Subsequently, the high efficiency and universality of the DPM strategy were successfully demonstrated in LCC, Est119, and BhrPETase enhancing the degradation activity of PET. Finally, the highest degradation rate of the pretreated commercial plastic bottles had reached to 73%. The present study provides insight into the molecular binding mechanism of PET into the PET hydrolases structure and proposes a novel DPM strategy that will be useful for the engineering of more efficient enzymes for PET degradation.

Changes in the Gut Metabolic Profile of Gestational Diabetes Mellitus Rats Following Probiotic Supplementation.

The roles of gut microbiota and metabolomics in women with gestational diabetes mellitus (GDM) are not well understood. This study investigated the gut metabolomic profiling of GDM rats and GDM rats treated with probiotic supplements. Associations between gut metabolites and microbiota were also studied in GDM rats. Liquid chromatography-mass spectrometry was used to detect gut metabolites in GDM rats and GDM rats treated with probiotic supplements of 0.5 g (low-dose group) or 1 g (high-dose group) for 15 days. Each gram of probiotic supplement contained 5 × 107 colony-forming units (CFU) of Lactobacillus rhamnosus LGG and 1 × 108 CFU of Bifidobacterium animalis subspecies lactis Bb12. The association between gut metabolites and microbiota in GDM rats was investigated using Spearman's correlation. Finally, 10 rats in the normal pregnant group, eight rats in the GDM model group, eight GDM rats in the low-dose probiotics group, and nine GDM rats in the high-dose probiotics group were further studied. Serum parameters and pancreatic and colon histology were significantly changed in GDM rats, and these were restored using probiotic supplements. In total, 999 gut metabolites were detected in the feces, and GDM rats were distinguished from normal rats. The levels of 44 metabolites were increased in GDM rats, and they were alleviated using probiotic supplements. Changes in metabolites in GDM rats were associated with amino acids and bile acids metabolism signaling pathways. Furthermore, changes in metabolites after probiotic supplementation were associated with porphyrin and chlorophyll metabolism pathways. We found that the Allobaculum genus displayed strong positive correlations, whereas the Bryobacter and Gemmatimonas genera displayed strong negative correlations with metabolisms of amino acids and bile acids in GDM rats. The Lactobacillus and Bifidobacterium genera were positively correlated with gut metabolites. Overall, our results showed that metabolism signaling pathways of amino acids and bile acids are associated with the development of GDM. Probiotic supplements alleviate the pathology of GDM through the metabolism pathways of amino acids, bile acids, porphyrin, and chlorophyll.