Risk factors and molecular characterization of carbapenem resistant Escherichia coli recovered from a tertiary hospital in Fujian, China from 2021 to 2023.

BACKGROUND: There is a serious public health concern regarding the emergence of carbapenem-resistant Escherichia coli (CREC). The purpose of this study is to identify the molecular characterization and risk factors of CREC in Fujian province, China. METHODS: A total of 48 CREC isolates were collected from various clinical samples. The strains were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Susceptibility to antibiotics was determined by the standard broth microdilution method. Polymerase chain reaction (PCR) was used to screen common drug resistance genes. Multilocus sequence typing (MLST) was used to type isolates. RT-qPCR was used to detect gene expression of acrA, acrB, and tolC. Conjugation assays were used to analyze the transferability of plasmids carrying mcr-1 or blaNDM. Risk factors for CREC infection were identified by logistic regression analysis. RESULTS: 48 CREC strains were collected, with 81.25% producing carbapenemase (CP-CREC), and 18.75% were not producing carbapenemase (no-CP-CREC). They belonged to 21 sequence type (STs) and five unknown STs. Perianal swabs were the main sample type, with 25 patients found to have hematological malignancies. All isolates of CP-CREC were found to contain blaNDM (blaNDM-5 (n = 32), blaNDM-1 (n = 5), blaNDM-4 (n = 1), and blaNDM-13 (n = 1)), among which one isolate co-existence blaNDM-5 and blaOXA-48. Two blaNDM-positive strains, specifically blaNDM-5 and blaNDM-4, were found to co-habor mcr-1 with ST617. Conjugation assays confirmed that blaNDM-1, blaNDM-13, and most blaNDM-5(68.75%, 22/32) could be transferred between E. coli strains. Four of the 9 non-CP-CREC isolates had deletions in ompC and ompF with blaCTX-M production, while the other five showed high expression of acrA, acrB, and tolC. Antibiotics usage, antifungal treatment, detection of other pathogens (prior to CREC infection), and respiratory disease were identified as independent risk factors for CREC infection. The area under the receiver operating characteristic curve for the scoring system was 0.937. Youden's index, with sensitivity and specificity of 0.96 and 0.78, was maximal when 2 points were scored. CONCLUSIONS: In CP-CREC, carbapenem resistance is caused primarily by multiple types of blaNDM, while non-CP-CREC is caused by loss of porin protein or high expression of efflux pumps coupled with carrying blaCTX-M. CREC isolates were highly diverse in terms of ST, with a total of 21 STs identified. Here, we first describe a clinical strain of CREC from China both mcr-1 and blaNDM -4 with ST617. An easy-to-use scoring system was developed to diagnose CREC infections.

N6-methyladenosine levels in peripheral blood RNA: a potential diagnostic biomarker for colorectal cancer.

BACKGROUND: N6-methyladenosine (m6A) is dysregulated in various cancers, including colorectal cancer (CRC). Herein, we assess the diagnostic potential of peripheral blood (PB) m6A levels in CRC. METHODS: We collected PB from healthy controls (HCs) and patients with CRC, analyzed PB RNA m6A levels and the expression of m6A-related demethylase genes FTO and ALKBH5, cocultured CRC cells with PB mononuclear cells (PBMCs), and constructed an MC38 cancer model. RESULTS: PB RNA m6A levels were higher in the CRC than that in HCs. The area under the curve (AUC) of m6A levels (0.886) in the CRC was significantly larger compared with carbohydrate antigen 199 (CA199; 0.666) and carcinoembryonic antigen (CEA; 0.834). The combination of CEA and CA199 with PB RNA m6A led to an increase in the AUC (0.935). Compared with HCs, the expression of FTO and ALKBH5 was decreased in the CRC. After coculturing with CRC cells, the PBMCs RNA m6A were significantly increased, whereas the expression of FTO and ALKBH5 decreased. Furthermore, m6A RNA levels in the PB of MC38 cancer models were upregulated, whereas the expression of FTO and ALKBH5 decreased. CONCLUSIONS: PB RNA m6A levels are a potential diagnostic biomarker for patients with CRC.

Prediction of injury localization in preoperative patients with gastrointestinal perforation: a multiomics model analysis.

BACKGROUND: The location of gastrointestinal perforation is essential for severity evaluation and optimizing the treatment approach. We aimed to retrospectively analyze the clinical characteristics, laboratory parameters, and imaging features of patients with gastrointestinal perforation and construct a predictive model to distinguish the location of upper and lower gastrointestinal perforation. METHODS: A total of 367 patients with gastrointestinal perforation admitted to the department of emergency surgery in Fujian Medical University Union Hospital between March 2014 and December 2020 were collected. Patients were randomly divided into training set and test set in a ratio of 7:3 to establish and verify the prediction model by logistic regression. The receiver operating characteristic curve, calibration map, and clinical decision curve were used to evaluate the discrimination, calibration, and clinical applicability of the prediction model, respectively. The multiomics model was validated by stratification analysis in the prediction of severity and prognosis of patients with gastrointestinal perforation. RESULTS: The following variables were identified as independent predictors in lower gastrointestinal perforation: monocyte absolute value, mean platelet volume, albumin, fibrinogen, pain duration, rebound tenderness, free air in peritoneal cavity by univariate logistic regression analysis and stepwise regression analysis. The area under the receiver operating characteristic curve of the prediction model was 0.886 (95% confidence interval, 0.840-0.933). The calibration curve shows that the prediction accuracy and the calibration ability of the prediction model are effective. Meanwhile, the decision curve results show that the net benefits of the training and test sets are greater than those of the two extreme models as the threshold probability is 20-100%. The multiomics model score can be calculated via nomogram. The higher the stratification of risk score array, the higher the number of transferred patients who were admitted to the intensive care unit (P < 0.001). CONCLUSION: The developed multiomics model including monocyte absolute value, mean platelet volume, albumin, fibrinogen, pain duration, rebound tenderness, and free air in the peritoneal cavity has good discrimination and calibration. This model can assist surgeons in distinguishing between upper and lower gastrointestinal perforation and to assess the severity of the condition.

Effectiveness of SARS-CoV-2-inactivated vaccine and the correlation to neutralizing antibodies: A test-negative case-control study.

Severe acute respiratory syndrome coronavirus 2 breakthrough infection in highly vaccinated populations raises study on the effectiveness for inactivated vaccine, including effectiveness of the vaccine dose, the continuance of effectiveness, the effectiveness against severe/critical coronavirus disease 2019 and against secondary attacks. A population of 10 870 close contacts were investigated in a Delta variant's epidemic. The effectiveness of vaccination was estimated in a test-negative case-control study. In addition, serum was used to detect neutralizing antibodies, to explore their correlation to effectiveness. The vaccine effectiveness (VE) values were estimated for populations aged 12 years or older. The overall adjusted VE was 56.2% and a two-dose vaccine was more effective than a one-dose vaccine (56.7% vs. 43.8%). In addition, the population that got the second dose vaccine within 2 months showed higher VE than the population vaccinated for longer than 2 months (61.5% vs. 52.3%). Among the population who vaccinated 2 doses or within 2 months, a higher level of neutralizing antibodies was observed. For infected cases, vaccinated populations showed lower rates of transmission (2.63% vs. 4.36%). Further, those vaccinated cases, who were not found causing transmission, had a higher level of antibodies. The study provided a full view of the effectiveness of inactivated vaccines in a real-world setting. The time-related VE against infection and lower transmission of breakthrough vaccinated cases were observed, which may indicate that a necessity of a booster vaccine to maintain the effectiveness and high level of neutralizing antibody.

Differentiation and prognostic stratification of acute myeloid leukemia by serum-based spectroscopy coupling with metabolic fingerprints.

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by complex molecular and cytogenetic abnormalities. New approaches to predict the prognosis of AML have increasingly attracted attention. There were 98 non-M3 AML cases and 48 healthy controls were enrolled in the current work. Clinically routine assays for cytogenetic and molecular genetic analyses were performed on the bone marrow samples of patients with AML. Meanwhile, metabolic profiling of these AML subjects was also performed on the serum samples by combining Ag nanoparticle-based surface-enhanced Raman spectroscopy (SERS) with proton nuclear magnetic resonance (NMR) spectroscopy. Although most of the routine biochemical test showed no significant differences between the M0-M2 and M5 groups, the metabolic profiles were significantly different either between AML subtypes or between prognostic risk subgroups. Specific SERS bands were screened to serve as potential markers for AML subtypes. The results demonstrated that the classification models for M0-M2 and M5 shared two bands (i.e., 1328 and 741 cm-1 ), all came from nucleic acid signals. Furthermore, Metabolic profiles provided various differential metabolites responsible for different AML subtypes, and we found altered pathways mainly included energy metabolism like glycolysis, pyruvate metabolism, and metabolisms of nucleic acid bases as well as specific amino acid metabolisms. It is concluded that integration of SERS and NMR provides the rational and could be reliable to reveal AML differentiation, and meanwhile lay the basis for experimental and clinical practice to monitor disease progression and prognostic evaluation.

Exosomal miR-155-5p drives widespread macrophage M1 polarization in hypervirulent Klebsiella pneumoniae-induced acute lung injury via the MSK1/p38-MAPK axis.

BACKGROUND: Hypervirulent Klebsiella pneumoniae (hvKp) infection-induced sepsis-associated acute lung injury (ALI) has emerged as a significant clinical challenge. Increasing evidence suggests that activated inflammatory macrophages contribute to tissue damage in sepsis. However, the underlying causes of widespread macrophage activation remain unclear. METHODS: BALB/c mice were intravenously injected with inactivated hvKp (iHvKp) to observe lung tissue damage, inflammation, and M1 macrophage polarization. In vitro, activated RAW264.7 macrophage-derived exosomes (iHvKp-exo) were isolated and their role in ALI formation was investigated. RT-PCR was conducted to identify changes in exosomal miRNA. Bioinformatics analysis and dual-luciferase reporter assays were performed to validate MSK1 as a direct target of miR-155-5p. Further in vivo and in vitro experiments were conducted to explore the specific mechanisms involved. RESULTS: iHvKp successfully induced ALI in vivo and upregulated the expression of miR-155-5p. In vivo, injection of iHvKp-exo induced inflammatory tissue damage and macrophage M1 polarization. In vitro, iHvKp-exo was found to promote macrophage inflammatory response and M1 polarization through the activation of the p38-MAPK pathway. RT-PCR revealed exposure time-dependent increased levels of miR-155-5p in iHvKp-exo. Dual-luciferase reporter assays confirmed the functional role of miR-155-5p in mediating iHvKp-exo effects by targeting MSK1. Additionally, inhibition of miR-155-5p reduced M1 polarization of lung macrophages in vivo, resulting in decreased lung injury and inflammation induced by iHvKp-exo or iHvKp. CONCLUSIONS: The aforementioned results indicate that exosomal miR-155-5p drives widespread macrophage inflammation and M1 polarization in hvKp-induced ALI through the MSK1/p38-MAPK Axis.

Profile and actual transmissibility of Carbapenem resistance genes: Intracellular and extracellular DNA in hospital wastewater.

The current worldwide spread of carbapenem resistance genes (CRGs) has posed a major public health threat, which continues to grow in severity. Hospital wastewaters (HWWs) are major reservoirs for antibiotic resistance genes, while resistomes in HWWs are still poorly characterized when it comes to CRGs. We comprehensively characterized the profile and actual transmissibility of extracellular CRGs (eCRGs) and intracellular CRGs (iCRGs) in HWWs for the first time. In this study, CRGs showed similar relative abundance in treated and untreated HWWs. Meanwhile, HWWs treatments led to the enrichment of blaIMP-8, probably attributed to the promotion of Novosphingobium and Prosthecobacter after treatment. To evaluate the transmission potential of CRGs, extracellular and intracellular carbapenem-resistant plasmids were captured from HWWs by transformation and conjugation, respectively. We found an interesting phenomenon regarding the transmission characteristics of CRGs: blaKPC-carrying plasmids could only be captured by transformation, while blaNDM-carrying plasmids were captured by conjugation. Further experiments showed that HWW treatments increased the conjugation ability of blaNDM. In conclusion, our study demonstrated that HWWs are significant reservoirs of CRGs and various CRGs exhibit different modes of transmission in HWWs. CRGs cannot be removed by membrane bioreactor and chlorine disinfection. An urgent need is to develop more efficient wastewater treatments to limit CRG dissemination.

Exosomes from bone marrow mesenchymal stem cells decrease chemosensitivity of acute myeloid leukemia cells via delivering miR-10a.

Bone marrow mesenchymal stem cells (BMSCs) are an integral part of the acute myeloid leukemia (AML) bone marrow microenvironment and contribute to AML progression. In this study, we explored the communication between BMSCs and AML cells via exosomes. The AML cells co-cultured with BMSCs-Exos were found to have lower chemosensitivity exposed to cytarabine, suggesting that BMSCs-Exos could protect AML cells from cytarabine. Interestingly, miR-10a was elevated in BMSCs-Exos derived from AML (AML-BMSCs-Exos) compared with that from healthy donor. The expression levels of miR-10a in AML cells was significantly up-regulated after co-culture with BMSCs-Exos. Furthermore, the up-regulated miR-10a was an crucial factor contributing to the chemoresistance of leukemia cells. Down-regulation of miR-10a substantially increase chemosensitivity of AML cells treated with BMSCs-Exos. Chemosensitivity of AML cells was also decreased through down-regulating RPRD1A by miR-10a that ultimately lead to the stimulation of the Wnt/ß-catenin signaling pathway. Collectively, our findings demonstrated that AML-BMSCs could deliver miR-10a to AML cells via exosomes, which could target RPRD1A and activate Wnt/ß-catenin signaling pathway that subsequently decreased chemosensitivity of AML cells.

Genetic manipulation of bermudagrass photosynthetic biosynthesis using Agrobacterium-mediated transformation.

Bermudagrass is one of the most extensively used warm-season grasses. It is widely used in landscaping, stadium construction and soil remediation due to its excellent regeneration, trampling and stress tolerances. However, studies on its regulatory mechanism and variety improvement by genetic engineering are still at a standstill, owing to its genetic variability and intrinsic limits linked with some resistance to Agrobacterium infection. In this study, we established a higher efficient Agrobacterium-mediated transformation via screening for vital embryogenic callus and improving infection efficiency. The superior callus was light yellow, hard granular and compact, determined with a differentiation rate of more than 95%. The optimized infestation courses by gentle shaking, vacuuming and sonicating were used. The infested calluses were co-cultured for 3 days, followed by desiccation treatments for 1 day to get higher infection efficiency. Then the CdHEMA1 gene, essential for chlorophyll biosynthesis, was cloned and transferred into bermudagrass to validate the aforementioned optimization procedures integrally. Molecular-level analyses indicated that the CdHEMA1 gene had successfully integrated and was greatly increased in transgenic seedlings. Results of the photosynthetic capacity assessment showed that CdHEMA1 overexpression may considerably enhance the contents of photosynthetic pigments, OJIP curve and reaction center density (RC/CSo) to absorb (ABS/CSo, ABS/CSM) and capture (TRo/CSo) more light energy, hence improve the performance indices PIABS and PICS compared to the wild type. The successful completion of this project would provide a solid platform for further gene function study and molecular breeding of bermudagrass.

MYB20, MYB42, MYB43, and MYB85 Regulate Phenylalanine and Lignin Biosynthesis during Secondary Cell Wall Formation.

Lignin is a phenylpropanoid-derived polymer that functions as a major component of cell walls in plant vascular tissues. Biosynthesis of the aromatic amino acid Phe provides precursors for many secondary metabolites, including lignins and flavonoids. Here, we discovered that MYB transcription factors MYB20, MYB42, MYB43, and MYB85 are transcriptional regulators that directly activate lignin biosynthesis genes and Phe biosynthesis genes during secondary wall formation in Arabidopsis (Arabidopsis thaliana). Disruption of MYB20, MYB42, MYB43, and MYB85 resulted in growth development defects and substantial reductions in lignin biosynthesis. In addition, our data showed that these MYB proteins directly activated transcriptional repressors that specifically inhibit flavonoid biosynthesis, which competes with lignin biosynthesis for Phe precursors. Together, our results provide important insights into the molecular framework for the lignin biosynthesis pathway.

Compare the Diagnostic and Prognostic Value of MLR, NLR and PLR in CRC Patients.

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer and it is a worldwide challenge. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) had been suggested as markers of CRC, but the role of monocyte-to-lymphocyte ratio (MLR) in CRC patients before surgery and chemotherapy is unclear. The study aimed to compare the diagnosis and prognosis value of MLR, NLR, and PLR in CRC. METHODS: A retrospective study was conducted on 783 patients with histologically confirmed colorectal cancer between 2015 and 2017 in Fujian Medical University Union Hospital. A total of 1,232 healthy age-matched participants were eligible for the study. Receiver-operating characteristic (ROC) analysis was performed to compare the area under the ROC curve (AUC) of MLR, NLR, PLR, carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9). Furthermore, chi-squared test was conducted to determine the prognostic values of MLR, NLR, and PLR. RESULTS: The levels of MLR, NLR, and PLR in CRC patients were significantly higher than those in 1,232 healthy participants. The area under the ROC curves (AUCs) of MLR, CEA, PLR, NLR, and CA19-9 were 0.739, 0.726, 0.683, 0.610, and 0.603, respectively. Moreover, the combined marker of CEA + MLR with an AUC of 0.815 acted as a superior diagnostic marker compared to the other combined markers, including the combined marker of CEA + CA19-9. Furthermore, the level of MLR was associated with tumor size (p = 0.001), and a high level of NLR was significantly correlated with pT stage (p = 0.048) and tumor size (p = 0.004). CONCLUSIONS: The present study shows for the first time that MLR rather than NLR and PLR is the better diagnostic marker for colorectal cancer, and NLR may be a better prognostic marker for CRC patients.

YouTube™ as a source of information for Candida auris infection: a systematic review.

BACKGROUND: Candida auris is a novel Candida species, and has emerged globally as a multidrug-resistant health care-associated fungal pathogen. YouTube™ (http://www.youtube.com) as the largest free video-sharing website is increasingly used to search health information. Thus, the aim of this study was to evaluate the content, reliability and quality of YouTube™ videos regarding Candida auris infection, and to identify whether it is a useful resource for people. METHODS: The YouTube™ was used to search systematically for videos using the keywords: "Candida auris infection" and "Candida auris". Strict inclusion and exclusion criteria were used to select the videos. The videos were reviewed and scored by two independent reviewers and recorded the "title", "length", "views", "comments", "dislike", "like", "posted days" and "category of videos". The videos were categorized as "poor", "good" and "excellent" by the score. The DISCERN tool was used to assess the reliability of the YouTube™ videos. RESULTS: Seventy-six videos were included in final analysis in our study. Most videos (59.2%, 55/76) had better quality. There were no statistically significant differences between groups in respect of the number of likes, dislikes, views, comments, percentage positivity, likebility, view rate and viewers' interaction. Length and posted days were significantly associated with the classification. The videos were categorized as "educational video", "new report", "personal experience and blog entertainment" and "interview". Significant differences were found in the source of videos and the characteristics of the individuals appearing in a video between the groups. CONCLUSION: YouTube™ has striking potential to be an effective user-friendly learning interface for people to obtain information of Candida auris infection.

Simultaneous regulation of F5H in COMT-RNAi transgenic switchgrass alters effects of COMT suppression on syringyl lignin biosynthesis.

Ferulate 5-hydroxylase (F5H) catalyses the hydroxylation of coniferyl alcohol and coniferaldehyde for the biosynthesis of syringyl (S) lignin in angiosperms. However, the coordinated effects of F5H with caffeic acid O-methyltransferase (COMT) on the metabolic flux towards S units are largely unknown. We concomitantly regulated F5H expression in COMT-down-regulated transgenic switchgrass (Panicum virgatum L.) lines and studied the coordination of F5H and COMT in lignin biosynthesis. Down-regulation of F5H in COMT-RNAi transgenic switchgrass plants further impeded S lignin biosynthesis and, consequently, increased guaiacyl (G) units and reduced 5-OH G units. Conversely, overexpression of F5H in COMT-RNAi transgenic plants reduced G units and increased 5-OH units, whereas the deficiency of S lignin biosynthesis was partially compensated or fully restored, depending on the extent of COMT down-regulation in switchgrass. Moreover, simultaneous regulation of F5H and COMT expression had different effects on cell wall digestibility of switchgrass without biomass loss. Our results indicate that up-regulation and down-regulation of F5H expression, respectively, have antagonistic and synergistic effects on the reduction in S lignin resulting from COMT suppression. The coordinated effects between lignin genes should be taken into account in future studies aimed at cell wall bioengineering.

Serum markers in the differential diagnosis of Waldenstrom macroglobulinemia and other IgM monoclonal gammopathies.

BACKGROUND: IgM monoclonal gammopathy can be present in a broad spectrum of diseases. We evaluated the value of serum markers in the differential diagnosis of Waldenstrom macroglobulinemia (WM) and other types of IgM monoclonal gammopathies. METHODS: We included patients who were first admitted to hospital and identified as having IgM monoclonal gammopathy by serum immunofixation electrophoresis (sIFE). We evaluated basic clinical features, sIFE, diagnosis, and serum markers. Furthermore, we applied the receiver operating characteristic (ROC) curve to analyze the differential diagnosis value of serum markers for WM. Finally, we used logistic regression and ROC curve to analyze the differential diagnosis value of multimarker combinations to identify WM. RESULTS: IgM monoclonal gammopathy was most frequently found in patients with Waldenstrom macroglobulinemia, followed by monoclonal gammopathy of undetermined significance (MGUS), B-cell non-Hodgkin Lymphoma (B-NHL), and multiple myeloma (MM). Serum markers showed significant differences among the four diseases. The diagnostic markers LDH, IgM, IgG, IgA, and serum light chain К had higher diagnostic efficiency. Among these markers, serum IgM provided the highest diagnostic efficiency. Additionally, the combined use of all five serum markers provided the most effective diagnosis. CONCLUSIONS: The five serum markers, LDH, IgM, IgG, IgA, and К, each yielded a specific efficacy in differential diagnosis of WM. The single marker with the highest diagnostic efficiency was the serum IgM level. However, a combination of multiple serum markers was better than the use of a single marker in diagnosing WM. The combined use of all five serum markers provided the most effective diagnosis, with an AUC of .952 and sensitivity and specificity of 87.8% and 86.9%, respectively.

Alteration of S-adenosylhomocysteine levels affects lignin biosynthesis in switchgrass.

Methionine (Met) synthesized from aspartate is a fundamental amino acid needed to produce S-adenosylmethionine (SAM) that is an important cofactor for the methylation of monolignols. As a competitive inhibitor of SAM-dependent methylation, the effect of S-adenosylhomocysteine (SAH) on lignin biosynthesis, however, is still largely unknown in plants. Expression levels of Cystathionine γ-synthase (PvCGS) and S-adenosylhomocysteine hydrolase 1 (PvSAHH1) were down-regulated by RNAi technology, respectively, in switchgrass, a dual-purpose forage and biofuel crop. The transgenic switchgrass lines were subjected to studying the impact of SAH on lignin biosynthesis. Our results showed that down-regulation of PvCGS in switchgrass altered the accumulation of aspartate-derived and aromatic amino acids, reduced the content of SAH, enhanced lignin biosynthesis and stunted plant growth. In contrast, down-regulation of PvSAHH1 raised SAH levels in switchgrass, impaired the biosynthesis of both guaiacyl and syringyl lignins and therefore significantly increased saccharification efficiency of cell walls. This work indicates that SAH plays a crucial role in monolignol methylation in switchgrass. Genetic regulation of either PvCGS or PvSAHH1 expression in switchgrass can change intracellular SAH contents and SAM to SAH ratios and therefore affect lignin biosynthesis. Thus, our study suggests that genes involved in Met metabolism are of interest as new valuable targets for cell wall bioengineering in future.

UDP-glycosyltransferase 72B1 catalyzes the glucose conjugation of monolignols and is essential for the normal cell wall lignification in Arabidopsis thaliana.

Glycosylation of monolignols has been found to be widespread in land plants since the 1970s. However, whether monolignol glycosylation is crucial for cell wall lignification and how it exerts effects are still unknown. Here, we report the identification of a mutant ugt72b1 showing aggravated and ectopic lignification in floral stems along with arrested growth and anthocyanin accumulation. Histochemical assays and thioacidolysis analysis confirmed the enhanced lignification and increased lignin biosynthesis in the ugt72b1 mutant. The loss of UDP-glycosyltransferase UGT72B1 function was responsible for the lignification phenotype, as demonstrated by complementation experiments. Enzyme activity analysis indicated that UGT72B1 could catalyze the glucose conjugation of monolignols, especially coniferyl alcohol and coniferyl aldehyde, which was confirmed by analyzing monolignol glucosides of UGT72B1 transgenic plants. Furthermore, the UGT72B1 gene was strongly expressed in young stem tissues, especially xylem tissues. However, UGT72B1 paralogs, such as UGT72B2 and UGT72B3, had weak enzyme activity toward monolignols and weak expression in stem tissues. Transcriptomic profiling showed that UGT72B1 knockout resulted in extensively increased transcript levels of genes involved in monolignol biosynthesis, lignin polymerization and cell wall-related transcription factors, which was confirmed by quantitative real-time PCR assays. These results provided evidence that monolignol glucosylation catalyzed by UGT72B1 was essential for normal cell wall lignification, thus offering insight into the molecular mechanism of cell wall development and cell wall lignification.

Molecular characteristic of mcr-1 producing Escherichia coli in a Chinese university hospital.

BACKGROUND: Colistin has been considered as a last-line treatment option in severe infections caused by multidrug-resistant (MDR) gram-negative pathogens. However, the emergence of the mobile colistin resistance gene (mcr-1) has challenged this viewpoint. The aim of this study is to explore the prevalence of mcr-1 in Escherichia coli (E. coli) in a Chinese teaching hospital, and investigate their molecular characteristics. METHODS: A total of 700 E. coli isolates were used to screen mcr-1 by PCR and sequencing in a Chinese university hospital from August 2014 to August 2015. Susceptibility test of mcr-1-producing isolates was determined by Vitek -2 Compact system. 26 virulence factors (VFs), phylogenetic groups, Multi-locus sequence typing (MLST), and DNA Fingerprinting (ERIC-PCR) of strains were investigated by PCR. RESULTS: Four (0.6%) mcr-1 producing E. coli isolates were found in this study. The results of antibiotic susceptibility test showed that all four isolates were resistant to colistin, ciprofloxacin, levofloxacin, cefazolin, and trimethoprim/sulfamethoxazole, and were susceptible to amikacin, ertapenem and imipenem. In addition, all 4 isolates exhibited high-level resistance to aztreonam, cefotaxime and gentamicin. The numbers of VFs contained in mcr-1 positive isolates were no more than 4 in our study. MLST result demonstrated that these isolates were assigned to two sequence types: ST156 and ST167. The result of phylogenetic analysis showed that four mcr-1-positive isolates belong to two phylogenetic groups: A and B1 group. ERIC-PCR showed that four mcr-1 positive strains were categorized into three different genotypes. CONCLUSIONS: Our study demonstrated a low prevalence of mcr-1 in E. coli clinical isolates in a Chinese teaching hospital, and we have gained insights into the molecular characteristics of these mcr-1-positive strains. Increasing the surveillance of these infections, as well as taking effective infection control measures are urgently needed to take to control the transmission of mcr-1 gene.

Mature dendritic cells cause Th17/Treg imbalance by secreting TGF-ß1 and IL-6 in the pathogenesis of experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is generally acknowledged to be an autoimmune disease, but its etiology remains unknown. The most intensively studied animal model of MS is experimental autoimmune encephalomyelitis (EAE). Dendritic cells (DCs), the professional antigen presenting cells (APCs), have gained increasing attention because they connect innate and adaptive immunity. The aim of this study was to determine the role of mature DCs in the pathogenesis of EAE. It was found that the number of mature DCs in the EAE spleen increased compared to the control group (p < 0.05). And there was an imbalance between Th17 (effector) and Treg (regulatory) in EAE. The data showed that mature DCs can regulate the differentiation of Th17 and Treg in EAE. In addition, there was a significant difference in secretion of TGF-ß1 and IL-6 between mature DCs from mice with EAE and controls. The present data suggest that mature DCs cause an imbalance between Th17 and Treg by secreting TGF-ß1 and IL-6 in the pathogenesis of EAE disease. Thus, targeting DC may be an effective strategy for treating MS.

Arabidopsis C3H14 and C3H15 have overlapping roles in the regulation of secondary wall thickening and anther development.

Plant tandem CCCH zinc finger (TZF) proteins play diverse roles in developmental and adaptive processes. Arabidopsis C3H14 has been shown to act as a potential regulator of secondary wall biosynthesis. However, there is lack of direct evidence to support its functions in Arabidopsis. It is demonstrated here that C3H14 and its homologue C3H15 redundantly regulate secondary wall formation and that they additionally function in anther development. Plants with double, but not single, T-DNA mutants for C3H14 or C3H15 have few pollen grains and thinner stem secondary walls than the wild type. Plants homozygous for c3h14 and heterozygous for c3h15 [c3h14 c3h15(±)] have slightly thinner secondary walls than plants heterozygous for c3h14 and homozygous for c3h15 [c3h14(±) c3h15], and c3h14(±) c3h15 have lower fertility. Overexpression of C3H14 or C3H15 led to increased secondary wall thickness in stems and the ectopic deposition of secondary walls in various tissues, but did not affect anther morphology. Transcript profiles from the C3H14/15 overexpression and c3h14 c3h15 plants revealed marked changes in the expression of many genes associated with cell wall metabolism and pollen formation. Subcellular localization and biochemical analyses suggest that C3H14/15 might function at both the transcriptional and post-transcriptional levels.