Bayesian network analysis of risk classification strategies in the regulation of cellular products.

Cell therapy, a burgeoning therapeutic strategy, necessitates a scientific regulatory framework but faces challenges in risk-based regulation due to the lack of a global consensus on risk classification. This study applies Bayesian network analysis to compare and evaluate the risk classification strategies for cellular products proposed by the Food and Drug Administration (FDA), Ministry of Health, Labour and Welfare (MHLW), and World Health Organization (WHO), using real-world data to validate the models. The appropriateness of key risk factors is assessed within the three regulatory frameworks, along with their implications for clinical safety. The results indicate several directions for refining risk classification approaches. Additionally, a substudy focuses on a specific type of cell and gene therapy (CGT), chimeric antigen receptor (CAR) T cell therapy. It underscores the importance of considering CAR targets, tumor types, and costimulatory domains when assessing the safety risks of CAR T cell products. Overall, there is currently a lack of a regulatory framework based on real-world data for cellular products and a lack of risk-based classification review methods. This study aims to improve the regulatory system for cellular products, emphasizing risk-based classification. Furthermore, the study advocates for leveraging machine learning in regulatory science to enhance the assessment of cellular product safety, illustrating the role of Bayesian networks in aiding regulatory decision-making for the risk classification of cellular products.

One-tube detection of Salmonella Typhimurium using LAMP and CRISPR-Cas12b.

Salmonella enterica serovar Typhimurium (ST) is a predominant serovar causing foodborne illnesses worldwide. Traditional detection methods often face challenges, including the need for specialized equipment, skilled operators, and lengthy procedures. To address these limitations, we developed a rapid, sensitive, and specific ST detection method by integrating loop-mediated isothermal amplification (LAMP) with the clustered regularly interspaced short palindromic repeats and associated protein 12b (CRISPR/Cas12b) system, all within a single tube. Our results indicate that the LAMP-CRISPR/Cas12b reaction can be completed isothermally in under 1 h without requiring specialized instruments. The platform's limit of detection (LoD) is 12.5 copies per reaction. Additionally, the system demonstrated 100% inclusivity and exclusivity when tested against 30 reference strains, highlighting its specificity. In practical applications, the LoDs for ST in pure nucleic acid and contaminated fecal samples were 2.32 and 23.2 CFU/mL, respectively, with higher sensitivity observed in pure nucleic acid samples. Overall, our findings underscore the potential of the one-tube LAMP-CRISPR/Cas12b platform as a rapid, sensitive, and specific tool for ST detection, particularly in resource-limited settings. IMPORTANCE: Here, we have provided a novel one-step method for Salmonella Typhimurium detection in one pot by integrating the LAMP assay with the CRISPR/Cas12b system, offering significant advantages in terms of simplicity, speed, and accuracy.

A One-Pot Convenient RPA-CRISPR-Based Assay for Salmonella enterica Serovar Indiana Detection.

Salmonella enterica serovar Indiana (S. Indiana) is among the most prevalent serovars of Salmonella and is closely associated with foodborne diseases worldwide. In this study, we combined a recombinase polymerase amplification (RPA) technique with clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated (Cas) protein Cas12b (CRISPR/Cas12b)-based biosensing in a one-pot platform to develop a novel one-step identification method for S. Indiana infection diagnosis. The entire RPA-CRISPR/Cas12b reaction can be completed at 41 °C within 1 h without the need for specific instruments. The optimal concentrations of Cas12b and single-guide RNA (sgRNA) for the reaction were the same at 250 nM. The single-stranded DNA (ssDNA) reporter 8C-FQ (5'-/6-FAM/CCCCCCCC/BHQ1/-3') presented the best performance in the reaction compared with the other reporters. The limit of detection (LoD) of the RPA-CRISPR/Cas12b assay was 14.4 copies per reaction. As for specificity, we successfully identified four S. Indiana strains among twenty-two Salmonella strains without any false-positive results, presenting 100% accuracy for S. Indiana, and no cross-reactions were observed in eight other pathogens. Moreover, a total of 109 chicken carcasses were classified by the S. Indiana RPA-CRISPR assay and PCR methods from three processing points, including 43 post-shedding, 35 post-evisceration, and 31 post-chilling. There were 17 S. Indiana-positive samples identified during the whole processing step, consisting of nine post-shedding, five post-evisceration, and three post-chilling. The corresponding S. Indiana-positive rates of post-shedding, post-evisceration, and post-chilling were 20.93% (9/43), 14.29% (5/35), and 9.68% (3/31), respectively. Results from the S. Indiana one-step RPA-CRISPR/Cas12b assay were totally in agreement with those obtained using a traditional culture method, demonstrating 100% agreement with no false-positive or false-negative results observed. Altogether, the RPA-CRISPR/Cas12b assay developed in this study represents a promising, accurate, and simple diagnostic tool for S. Indiana detection.

siRNA targeting Atp5a1 gene encoding ATPase α, the ligand of Peg fimbriae, reduced Salmonella Enteritidis adhesion.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a zoonotic pathogen that can infect both humans and animals. Among the 13 types of fimbrial operons in S. Enteritidis, the highly conserved Peg fimbriae play a crucial role in the adhesion and invasion of S. Enteritidis into host cells but are not well studied. In this study, we identified the ATP synthase subunit alpha (ATPase α) as a ligand of Peg fimbriae using ligand blotting and mass spectrometry techniques. We confirmed the in vitro binding of ATPase α to the purified adhesion protein (PegD). Furthermore, we used siRNA to suppress the expression of ATPase α gene Atp5a1 in Leghorn male hepatoma (LMH) cells, which resulted in a significant reduction in the adhesion rate of S. Enteritidis to the cells (P < 0.05). The findings in this study provide insight into the mechanism of S. Enteritidis infection through Peg fimbriae and highlight the importance of ATPase α in the adhesion process.RESEARCH HIGHLIGHTS Ligand blotting was performed to screen the ligand of S. Enteritidis Peg fimbriae.Binding assay confirmed that ATPase α is the ligand of the Peg fimbriae.siRNA targeting ATPase α gene (Atp5a1) significantly reduced S. Enteritidis adhesion.

Multi-omics blood atlas reveals unique features of immune and platelet responses to SARS-CoV-2 Omicron breakthrough infection.

Although host responses to the ancestral SARS-CoV-2 strain are well described, those to the new Omicron variants are less resolved. We profiled the clinical phenomes, transcriptomes, proteomes, metabolomes, and immune repertoires of >1,000 blood cell or plasma specimens from SARS-CoV-2 Omicron patients. Using in-depth integrated multi-omics, we dissected the host response dynamics during multiple disease phases to reveal the molecular and cellular landscapes in the blood. Specifically, we detected enhanced interferon-mediated antiviral signatures of platelets in Omicron-infected patients, and platelets preferentially formed widespread aggregates with leukocytes to modulate immune cell functions. In addition, patients who were re-tested positive for viral RNA showed marked reductions in B cell receptor clones, antibody generation, and neutralizing capacity against Omicron. Finally, we developed a machine learning model that accurately predicted the probability of re-positivity in Omicron patients. Our study may inspire a paradigm shift in studying systemic diseases and emerging public health concerns.

The efficacy and safety of temperature controlled dual-mode radiofrequency in women with vaginal laxity.

OBJECTIVE: Vaginal laxity could negatively influence women's sexual function. This study aimed to explore the efficacy and safety of temperature controlled dual-mode (monopolar and bipolar) radiofrequency (RF) in women with vaginal laxity. METHODS: A total of 102 patients with vaginal laxity were treated with temperature-controlled RF. The present study implemented Vaginal Laxity Questionnaire (VLQ), Female Sexual Function Index (FSFI) questionnaire and Sexual Satisfaction Questionnaire (SSQ) on all patients at baseline and after treatment. Pelvic Organ Prolapse Quantification System (POP-Q) system was applied to physical examination, and vaginal manometer to examine the strength of voluntary contractions of the pelvic floor muscles. RESULTS: The VLQ score was gradually increased after RF treatment at 1, 3, 6 and 12 months, accompanying by the significant improvement in total FSFI scores and the six domains (sexual desire, sexual arousal, lubrication, orgasm, satisfaction, pain). The increased sexual satisfaction based on the SSQ score was found after temperature-controlled RF. The result of POP-Q stage showed significant difference in women after treatment, with the women having Stage I of 45.10% at baseline, 36.27% at 1 month, 28.43% at 3 months, 19.61% at 6 months and 10.78% at 12 months. The mean pressure and mean duration of pelvic contractions were increased gradually at the 1-, 3-, 6- and 12- month follow-up. CONCLUSION: Temperature controlled dual-mode (monopolar and bipolar) radiofrequency may be associated with improvement of vaginal laxity, and contribute to enhancement to female sexual function and pelvic floor muscles.

LF-ACO: an effective formation path planning for multi-mobile robot.

Multi-robot path planning is a hot problem in the field of robotics. Compared with single-robot path planning, complex problems such as obstacle avoidance and mutual collaboration need to be considered. This paper proposes an efficient leader follower-ant colony optimization (LF-ACO) to solve the collaborative path planning problem. Firstly, a new Multi-factor heuristic functor is proposed, the distance factor heuristic function and the smoothing factor heuristic function. This improves the convergence speed of the algorithm and enhances the smoothness of the initial path. The leader-follower structure is reconstructed for the position constraint problem of multi-robots in a grid environment. Then, the pheromone of the leader ant and the follower ants are used in the pheromone update rule of the ACO to improve the search quality of the formation path. To improve the global search capability, a max-min ant strategy is used. Finally, the path is optimized by the turning point optimization algorithm and dynamic cut-point method to improve path quality further. The simulation and experimental results based on MATLAB and ROS show that the proposed method can successfully solve the path planning and formation problem.

Brusatol Derivative-34 Attenuates Allergic Airway Inflammation Via Inhibition of the Spleen Tyrosine Kinase Pathway.

Brusatol derivative-34 (Bru-34), a derivative of brusatol, has been shown significantly anti-inflammatory activity in mice in our previously work. However, to our knowledge, there were very limited studies on how Bru-34 affected airway inflammation. Thus, in this present study, the effects and potential mechanisms of Bru-34 on allergic airway inflammation were examined both in vivo and in vitro. The results showed that Bru-34 attenuated the allergic airway inflammation in mice, with significant decreasing of the inflammatory cells and mediators in bronchoalveolar lavage fluids and attenuation of the histopathological alterations in the lung tissues. In addition, Bru-34 significantly inhibited the release of inflammatory cytokines in antigen induced rat basophilic leukemia -2H3 (RBL-2H3) cells. What's more, Bru-34 significantly decreased the expression of spleen tyrosine kinase (Syk), p-Syk, cytoplasmic phospholipase A2 (cPLA2), p-cPLA2, nuclear factor-κB (NF-κB) and p-NF-κB both in allergic mice lung tissue and antigen induced RBL-2H3 cells. Furthermore, the collaborative effects of Bru-34 with inhibitors against Syk, cPLA2, and NF-κB, showed that Syk was an important target of Bru-34, and cPLA2 and NF-κB played important roles in the coordinated inflammatory response. In conclusion, Bru-34 could significantly modulate the allergic airway inflammation, and its potential mechanism was revealed at least partially via down-regulating of Syk-cPLA2 -NF-κB signaling.

Gut microbiomes of bigheaded carps and hybrids provide insights into invasion: A hologenome perspective.

Gut microbiomes play an essential role in host survival and local adaptation and thus can facilitate the invasion of host species. Biological invasions have been shown to be linked to the genetic properties of alien host species. It is thus plausible that the holobiont, the host, and its associated microbiome act as an entity to drive invasion success. The bighead carp and silver carp (bigheaded carps), invasive species that exhibit extensive hybridization in the Mississippi River Basin (MRB), provided a unique model to test the holobiont hypothesis of invasion. Here, we investigated the microbiomes of foreguts and hindguts in bigheaded carps and their reciprocal hybrids reared in aquaculture ponds using 16S amplicons and the associated gene prediction. We found an admixed pattern in the gut microbiome community in bigheaded carp hybrids. The hybrid gut microbiomes showed special characteristics such as relatively high alpha diversity in the foregut, an increasing dissimilarity between foreguts and hindguts, and a remarkable proportion of genes coding for putative enzymes related to their digestion of main food resources (Cyanobacteria, cellulose, and chitin). The pond-reared hybrids had advantageous features in genes coding for putative enzymes related to their diet. The above results collectively suggested that the gut microbiomes of hybrids could be beneficial to their local adaptation (e.g., food resource utilization), which might have facilitated their invasion in the MRB. The gut microbial findings, along with the intrinsic genomic features likely associated with life-history traits revealed in our recent study, provide preliminary evidence supporting the holobiont hypothesis of invasion.

[Construction and evaluation of a pUC-type prokaryotic promoter reporter system based on lacZ gene].

To construct a prokaryotic promoter report system with wide applicability, a series of pFGH reporter vectors based on lacZ gene and pUC replicon were constructed from plasmid pFLX107 through the replacement of multiple cloning sites and sequence modifications. The plasmid with the lowest background activity was selected as the final report system with the lacZ gene deletion strain MC4100 as the host bacterium, following by testing with inducible promoter araBAD and the constitutive promoter rpsM. The background activity of pFGH06 was significantly lower than that of other plasmids of the same series, and even lower than that of reference plasmid pRCL at 28 °C (P<0.01). Further evaluation tests show that the plasmid pFGH06 could be used to clone and determine the activity of inducible promoter or constitutive promoter, and the complete recognition of the target promoter could be achieved through blue-white selection in the simulation test of promoter screening. Compared with the reported prokaryotic promoter report systems, pFGH06 has the advantages of smaller size, more multiple clone sites, adjustable background activity, high efficiency of promoter screening and recognition, thus with a wide application prospect.

Thrombosis among 1537 patients with JAK2V617F -mutated myeloproliferative neoplasms: Risk factors and development of a predictive model.

To explore the risk factors of thrombosis in patients with JAK2V617F -mutated myeloproliferative neoplasms (MPNs), a cohort of 1537 Chinese patients with JAK2V617F -mutated MPN was retrospectively analyzed. The Kaplan-Meier method and multivariate Cox analysis were used to study the risk factors of thrombosis in patients with JAK2V617F -mutated MPN. Among the 1537 MPN patients, 931, 468, and 138 had polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), respectively. The median follow-up time was 7 years (range 1-47), and 12.8% of patients (197/1537) died during this period. A total of 16.8% (259/1399) of PV and ET patients had secondary myelofibrosis, and 2.5% (38/1537) of patients developed acute myeloid leukemia (AML). Thrombotic events occurred in 43.9% (675/1537) of patients, among which 91.4% (617/675) were arterial thrombosis and 16.6% (112/675) were venous thrombosis. The number of thrombotic events in PV, ET, and PMF patients was 439 (47.2%), 197 (42.1%) and 39 (28.2%), respectively. The multivariate analysis indicated that age ≥60 years old, HCT ≥48%, at least one cardiovascular risk factor, a history of thrombosis, and JAK2V617F allele burden (V617F%) ≥50% are risk factors for thrombosis in JAK2V617F -mutated MPN. According to the results of the multivariate analysis, a risk model of thrombosis was established and comprised low-risk (0 points), intermediate-risk (1 points) and high-risk (≥2 points) groups, among which the incidence of thrombosis was 9.1%, 33.7% and 72.9%. For elderly patients with JAK2V617F -mutated MPN and a history of thrombosis, reducing the V617F%, controlling HCT and preventing cardiovascular risk factors are necessary measures to prevent thrombosis.

Study on the influence of assistant experience on the quality of colonoscopy: A pilot single-center study.

BACKGROUND AND OBJECTIVE: Colonoscopy is the most important method for the diagnosis and treatment of intestinal diseases, and there are many factors affecting the quality of examination. Although the assistant is one of the factors influencing the quality of colonoscopy, there are few studies on the effect of different assistants with different experiences on the quality of colonoscopy. Therefore, the study was aimed to research the correlation between different assistants with different experiences and the quality of water-injection colonoscopy. METHOD: In this study, a single-center randomized controlled trial was conducted to analyze the key quality indicators (the rate to arrive cecum, time to arrive cecum, total operation time, detection rate of polyps, detection rate of adenoma, pain score, operation satisfaction, and the pressure on abdomen) of patients who underwent water-injection colonoscopy under non-sedation from January 2018 to June 2018 in the center. Patients were randomly assigned to different assistant groups based on the actual working period of 6 months (0∼6 months inexperienced assistant group and assistant group with more than 6 months of experience). Through fitting the bivariate and multivariate logistic regression models, the differences between the two groups and the effects on the key quality indicators of colon examination were analyzed. RESULTS: A total of 331 patients who were eligible for non-sedation colonoscopy were randomly assigned to the experienced assistant group (n = 179) and the inexperienced assistant group (n = 152). Among them, 103 cases of polyp and 70 cases of adenoma were detected. The rate to arrive cecum, polyp detection rate and adenoma detection rate were compared between the two groups during operation (P > 0.05). However, there were significant differences in the time to arrive cecum, patients' satisfaction with operation, pain score and abdominal pressure (P < .05). In the inexperienced assistant group, 20% of the operation time was one standard deviation higher than the mean value, while the experienced assistant group was 12% (339 s vs 405s, OR 0.541, 95% 0.295-0.990). Compared with the inexperienced assistant group, patients in the experienced assistant group had higher operational satisfaction (98.32% vs 92.11%, OR 0.199, 95% 0.055-0.718) and lower pain score (0.3 vs 0.49, OR 1.993, 95% 1.52-3.775). All relations remained unchanged after adjusting for potential confounders. CONCLUSION: The assistant is a key factor in the quality of colonoscopy, especially in the case of non-sedating colonoscopy. The experience of the assistant is related to the time to arrive cecum, the degree of pain and the overall satisfaction of patient with the operation. The assistant should be subject to the quality supervision of the endoscopic inspector. Proof of human Clinical Trial Registration: The institutional review board of Fifth Affiliated Hospital of Wenzhou Medical College, Zhejiang Province, China approved the study. The study is registered on. Chinese Clinical Trial Registry (ChiCTR1800015650).

Use of a modified bacterial ghost lysis system for the construction of an inactivated avian pathogenic Escherichia coli vaccine candidate.

Vaccination is an effective strategy to prevent avian colibacillosis. Bacterial ghosts (BGs) are prepared by the controlled expression of the phiX174 gene E, which mediates the lysis of Gram-negative bacteria. Staphylococcal nuclease A may be used to produce BGs for further inactivation of host bacteria and elimination of residual genetic material. In this study, the double promoter lysis plasmid (pUC19-ΔcI857-E-rrnB-pL-SN) was successfully constructed and BGs were prepared at 37 °C. The cleavage efficiency of Escherichia coli BGs was 99.9%. Furthermore, to evaluate the immunological effects of the BG vaccines in chickens, a BG vaccine was prepared using the serotype O2 avian pathogenic Escherichia coli deletion strain (DE17ΔluxSΔaroA). The results showed that the BG vaccine was able to achieve over 90% immune protection against virulent challenge using the same serotype O2 strain (DE17 or CE35), while it showed poor cross-protection against serotypes O1 and O78 (data not shown). The enzyme-linked immunosorbent assay results showed that the antibody levels in the immunized groups were higher than in the control group (p < 0.05), with the BG group being the highest. The cytokine tests showed that the levels of interferon-γ in the BG immune group were higher than in the phosphate-buffered saline (PBS) control group (non-immune) (p < 0.01) and the formalin-inactivated vaccine immune group (p < 0.05), and the levels of tumor necrosis factor-α in the BG group were higher than in the formalin-inactivated vaccine (p > 0.05) and the PBS control groups (p < 0.05). In addition, pathological analysis revealed that the PBS control group showed typical fibrinous pericarditis and perihepatitis, whereas the immune group showed no obvious pathological changes. In summary, our findings provide a new strategy for the prevention and control of avian colibacillosis.

Tulobuterol patch alleviates allergic asthmic inflammation by blockade of Syk and NF-κB activation in mice.

BACKGROUND: Tulobuterol patch, one of strongest bronchodilators, was recently shown to improve bronchial hyperresponsiveness and significantly decrease the sputum eosinophil counts by combining with nonspecific anti-inflammatory drugs on patients with asthma. However, there is limited study on the anti-inflammatory activities of tulobuterol patch and its potential machenism. RESULTS: The tulobuterol patch significantly ameliorated inflammatory cell infiltration in the lung tissue, reduced the number of total leukocytes and its differential count, markedly reduced the production of IL-1ß, TNF-α, IL-6, CCL-11 and IL-4 in bronchial alveolar lavage fluid, as well as a reduction in IL-4/IFN-γ ratio. Tulobuterol patch exhibited the best effect on allergic inflammation compared with formoterol and salbutamol. Furthermore, tulobuterol patch treatment significantly suppressed the expression and activation of Syk and its downdream signaling NF-κB and p-NF-κB. CONCLUSIONS: The present studies revealed that tulobuterol patch effectively ameliorated airway inflammatory responses in allergic asthma, and its mechanisms, at least partially, via down-regulating Syk/NF-κB pathway. METHODS: An ovalbumin induced allergic asthma mouse model were used, and the effects of tulobuterol patch on allergic airway inflammation were evaluated. Also, its anti-airway inflammatory potential was compared with two other ß2-agonists, salbutamol and formoterol. Its possible anti-inflammatory mechanisms were identified by using western blotting and immunohistochemistry.

[Comparison of three methods for preparation of bacterial ghosts from avian pathogenic Escherichia coli].

Bacterial ghosts are bacterial cell envelopes devoid of cytoplasmic contents while maintaining their cellular morphology, which can be used as a new vaccine and delivery vector. In this study, a clinical isolate of avian pathogenic Escherichia coli (APEC) strain DE17 was used to prepare bacterial ghost through three different ways. The results showed that the cleavage efficiency of DE17 bacterial ghost was 99.9% with the lysis plasmid containing the PhiX174 lysis gene E. Scanning electron microscopy showed that transmembrane tunnels were formed in the middle or both ends of the cell envelope of DE17. Furthermore, the DE17 bacterial ghost was prepared with one of cell penetrating peptides (CPPs) named MAP (KLALKLALKALKAALKLA), which will completely inactivate DE17 (OD600=0.1) by 10 µmol/L MAP. The cell envelope showed a gully-like structure and obvious transmembrane tunnels were not found through the SEM. However, the DE17 could not be lysed by importing the lysis plasmid (pBV220-MAP), which was used to express MAP. The present study will benefit for research on bacterial ghost preparation methods and provide a reference for biosafety of bacterial ghost vaccines.

Cigarette Smoke-Induced Pulmonary Inflammation and Autophagy Are Attenuated in Ephx2-Deficient Mice.

Cigarette smoke (CS) increases the risk of chronic obstructive pulmonary disease (COPD) by causing inflammation, emphysema, and reduced lung function. Additionally, CS can induce autophagy which contributes to COPD. Arachidonic acid-derived epoxyeicosatrienoic acids (EETs) have promising anti-inflammatory properties that may protect the heart and liver by regulating autophagy. For this reason, the effect of decreased soluble epoxide hydrolase (sEH, Ephx2)-mediated EET hydrolysis on inflammation, emphysema, lung function, and autophagy was here studied in CS-induced COPD in vivo. Adult male wild-type (WT) C57BL/6J and Ephx2-/- mice were exposed to air or CS for 12 weeks, and lung inflammatory responses, air space enlargement (emphysema), lung function, and autophagy were assessed. Lungs of Ephx2-/- mice had a less pronounced inflammatory response and less autophagy with mild distal airspace enlargement accompanied by restored lung function and steady weight gain. These findings support the idea that Ephx2 may hold promise as a therapeutic target for COPD induced by CS, and it may be protective property by inhibiting autophagy.

Genome resequencing and comparative variome analysis in a Brassica rapa and Brassica oleracea collection.

The closely related species Brassica rapa and B. oleracea encompass a wide range of vegetable, fodder and oil crops. The release of their reference genomes has facilitated resequencing collections of B. rapa and B. oleracea aiming to build their variome datasets. These data can be used to investigate the evolutionary relationships between and within the different species and the domestication of the crops, hereafter named morphotypes. These data can also be used in genetic studies aiming at the identification of genes that influence agronomic traits. We selected and resequenced 199 B. rapa and 119 B. oleracea accessions representing 12 and nine morphotypes, respectively. Based on these resequencing data, we obtained 2,249,473 and 3,852,169 high quality SNPs (single-nucleotide polymorphisms), as well as 303,617 and 417,004 InDels for the B. rapa and B. oleracea populations, respectively. The variome datasets of B. rapa and B. oleracea represent valuable resources to researchers working on evolution, domestication or breeding of Brassica vegetable crops.

Construction of efficient Streptococcus zooepidemicus strains for hyaluoronic acid production based on identification of key genes involved in sucrose metabolism.

Biosynthesis of polysaccharide hyaluoronic acid (HA) by Streptococcus zooepidemicus is a carbon-intensive process. The carbon flux and factor(s) restricting HA yield were not well understood. Here, we investigated the function of genes involved in sucrose metabolism and identified targets limiting HA yield, which were exploited to construct efficient S. zooepidemicus strains for HA production. The sucrose uptake was addressed by deletion of scrA and scrB, which encodes sucrose-PTS permease and sucrose-6-phosphate hydrolase, respectively. We found that scrB was essential for the growth of S. zooepidemicus and HA biosynthesis, and accumulation of sucrose-6-phosphate was toxic. ΔscrB could not grow in THY-sucrose medium, while ΔscrA and ΔscrAΔscrB showed negligible growth defects. Overexpression of scrA significantly reduced biomass and HA production, while overexpression of scrB resulted in 26% increase of biomass and 30% increase of HA yield. We revealed that fructose-6-phosphate for HA biosynthesis mainly originates from glucose-6-phosphate. Deletion of scrK, a gene encoding hexokinase, led to 11% reduction of biomass and 12% decrease of HA yield, while deletion of hasE, a gene encoding phosphoglucoisomerase, resulted in the abolishment of HA biosynthesis and a significantly slow growth. We found that HA biosynthesis could be improved by directing carbon flux to fructose-6-phosphate. Deletion of fruA encoding the EII of fructose-PTS and fruK encoding phosphofructokinase showed no apparent effect on cell growth, but resulted in 22 and 27% increase of HA yield, respectively. Finally, a strain with 55% increase of HA was constructed by overexpression of scrB in ΔfruK. These results provide a solid foundation for further metabolic engineering of S. zooepidemicus for highly efficient HA production.

14,15-Epoxyeicosatrienoic acid suppresses cigarette smoke condensate-induced inflammation in lung epithelial cells by inhibiting autophagy.

Epoxyeicosatrienoic acids (EETs) are metabolic products of free arachidonic acid, which are produced through cytochrome P-450 (CYP) epoxygenases. EETs have anti-inflammatory, antiapoptotic, and antioxidative activities. However, the effect of EETs on cigarette smoke-induced lung inflammation is not clear. Autophagy is believed to be involved in the pathogenesis of chronic obstructive pulmonary disease. In addition, nuclear erythroid-related factor 2 (Nrf2), a transcription factor that regulates many antioxidant genes, is thought to regulate antioxidant defenses in several lung diseases. In addition, interaction between EETs, autophagy, and Nrf2 has been reported. The aim of this study was to explore the effect of 14,15-EET on cigarette smoke condensate (CSC)-induced inflammation in a human bronchial epithelial cell line (Beas-2B), and to determine whether the underlying mechanisms involved in the regulation of Nrf2 through inhibition of autophagy. Autophagy and expression of autophagy signaling pathway proteins (LC3B, p62, PI3K, Akt, p-Akt, and p-mTOR) and anti-inflammatory proteins (Nrf2 and HO-1) were assessed via Western blot analysis. Autophagosomes and autolysosomes were detected by adenoviral mRFP-GFP-LC3 transfection. Inflammatory factors (IL-6, IL-8, and MCP-1) were detected by ELISA. Lentiviral vectors carrying p62 short hairpin RNA were used to interfere with p62 expression to evaluate the effect of p62 on Nrf2 expression. Nrf2 expression was determined through immunocytochemistry. 14,15-EET treatment resulted in a significant reduction in IL-6, IL-8, and MCP-1 secretion, and increased accumulation of Nrf2 and expression of HO-1. In addition, 14,15-EET inhibited CSC-induced autophagy in Beas-2B cells. The mechanism of the anti-inflammatory effect of 14,15-EET involved inhibition of autophagy and an increase in p62 levels, followed by translocation of Nrf2 into the nucleus, which then upregulated expression of the antioxidant enzyme HO-1. 14,15-EET protects against CSC-induced lung inflammation by promoting accumulation of Nrf2 via inhibition of autophagy.

Subgenome parallel selection is associated with morphotype diversification and convergent crop domestication in Brassica rapa and Brassica oleracea.

Brassica species, including crops such as cabbage, turnip and oilseed, display enormous phenotypic variation. Brassica genomes have all undergone a whole-genome triplication (WGT) event with unknown effects on phenotype diversification. We resequenced 199 Brassica rapa and 119 Brassica oleracea accessions representing various morphotypes and identified signals of selection at the mesohexaploid subgenome level. For cabbage morphotypes with their typical leaf-heading trait, we identified four subgenome loci that show signs of parallel selection among subgenomes within B. rapa, as well as four such loci within B. oleracea. Fifteen subgenome loci are under selection and are shared by these two species. We also detected strong subgenome parallel selection linked to the domestication of the tuberous morphotypes, turnip (B. rapa) and kohlrabi (B. oleracea). Overall, we demonstrated that the mesohexaploidization of the two Brassica genomes contributed to their diversification into heading and tuber-forming morphotypes through convergent subgenome parallel selection of paralogous genes.