Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis.

DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also enriched in MYC-translocated diffuse large B cell lymphoma and reveal functional cooperation between mutant DDX3X and MYC. DDX3X promotes the translation of mRNA encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y chromosome homolog, the expression of which is normally restricted to the testis. These findings show that DDX3X loss of function can buffer MYC-driven proteotoxic stress and highlight the capacity of male B cell lymphomas to then compensate for this loss by ectopic DDX3Y expression.

A point mutation in the gene encoding magnesium chelatase I subunit influences strawberry leaf color and metabolism.

Magnesium chelatase (MgCh) catalyzes the insertion of magnesium into protoporphyrin IX, a vital step in chlorophyll (Chl) biogenesis. The enzyme consists of 3 subunits, MgCh I subunit (CHLI), MgCh D subunit (CHLD), and MgCh H subunit (CHLH). The CHLI subunit is an ATPase that mediates catalysis. Previous studies on CHLI have mainly focused on model plant species, and its functions in other species have not been well described, especially with regard to leaf coloration and metabolism. In this study, we identified and characterized a CHLI mutant in strawberry species Fragaria pentaphylla. The mutant, noted as p240, exhibits yellow-green leaves and a low Chl level. RNA-Seq identified a mutation in the 186th amino acid of the CHLI subunit, a base conserved in most photosynthetic organisms. Transient transformation of wild-type CHLI into p240 leaves complemented the mutant phenotype. Further mutants generated from RNA-interference (RNAi) and CRISPR/Cas9 gene editing recapitulated the mutant phenotype. Notably, heterozygous chli mutants accumulated more Chl under low light conditions compared with high light conditions. Metabolite analysis of null mutants under high light conditions revealed substantial changes in both nitrogen and carbon metabolism. Further analysis indicated that mutation in Glu186 of CHLI does not affect its subcellular localization nor the interaction between CHLI and CHLD. However, intramolecular interactions were impaired, leading to reduced ATPase and MgCh activity. These findings demonstrate that Glu186 plays a key role in enzyme function, affecting leaf coloration via the formation of the hexameric ring itself, and that manipulation of CHLI may be a means to improve strawberry plant fitness and photosynthetic efficiency under low light conditions.

Survival analysis and individualized prediction of survival benefit for pancreatic signet ring cell carcinoma: a population study based on the SEER database.

OBJECTIVES: This study aimed to compare the incidence, clinicopathological characteristics and survival results of pancreatic signet ring cell carcinoma (PSRCC) and pancreatic adenocarcinomas (PDAC), as well as to analyze the clinical characteristics related to the overall survival (OS) of PSRCC, and to establish an effective prognostic nomogram to predict the risks associated with patient outcomes. METHODS: A total of 85,288 eligible patients including 425 PSRCC and 84,863 PDAC cases were retrieved from the Surveillance, Epidemiology, and End Results database. The survival curve was calculated using the Kaplan-Meier method and differences in them were measured by Log-rank tests. The Cox proportional hazards regression model was used to identify independent predictors of OS in patients with PSRCC. A nomogram was constructed to predict 1-, 3-, and 5-year OS. The performance of the nomogram was measured by C-index, receiver operating characteristic (ROC) curve, decision curve analysis (DCA). RESULTS: The incidence of PSRCC is much lower than that of PDAC (10.798 V.S. 0.349 per millions). PSRCC is an independent predictor of pancreatic cancer with a poorer histological grade, a higher rate of lymph node and distant metastasis, and a poorer prognosis. We identified four independent prognostic factors including grade, American Joint Committee on Cancer Tumor-Node-Metastasis (TNM) stage, surgery and chemotherapy based on the Cox regression model. The C-index and DCA curves showed better performance of the nomogram than TNM stage. ROC curve analysis also showed that the nomogram had good discrimination, with an area under the curve of 0.840, 0.896, and 0.923 for 1-, 3-, and 5-year survival. The calibration curves showed good agreement between the prediction by the nomogram and actual observations. CONCLUSION: PSRCC is a rare but fatal subtype of pancreatic cancer. The constructed nomogram in this study accurately predicted the prognosis of PSRCC, performed better than the TNM stage.

Association between hyperuricemia and acute kidney injury in critically ill patients with sepsis.

BACKGROUND: Sepsis-related AKI is related to short-term mortality and poor long-term prognoses, such as chronic renal insufficiency, late development of end-stage renal disease, and long-term mortality. In this study, we aimed to investigate the association of hyperuricemia with acute kidney injury (AKI) in patients with sepsis. METHODS: The retrospective cohort study included 634 adult sepsis patients hospitalized in the intensive care unit (ICU) of the First Affiliated Hospital of Guangxi Medical University from March 2014 to June 2020 and the ICU of the Second Affiliated Hospital of Guangxi Medical University from January 2017 to June 2020. Based on the first serum uric acid level within 24 h of admission to the ICU, patients were divided into groups with or without hyperuricemia, and the incidence of AKI within seven days of ICU admission was compared between the two groups. The univariate analysis analyzed the effect of hyperuricemia on sepsis-related AKI, and the multivariable logistic regression model analysis was used. RESULTS: Among the 634 patients with sepsis, 163 (25.7%) developed hyperuricemia, and 324 (51.5%) developed AKI. The incidence of AKI in the groups with and without hyperuricemia was 76.7% and 42.3%, respectively, with statistically significant differences (2 = 57.469, P < 0.001). After adjusting for genders, comorbidities (coronary artery disease), organ failure assessment (SOFA) score on the day of admission, basal renal function, serum lactate, calcitonin, and mean arterial pressure, hyperuricemia was showed to be an independent risk factor for AKI in patients with sepsis (OR = 4.415, 95%CI 2.793 ~ 6.980, P < 0.001). For every 1 mg/dL increase in serum uric acid in patients with sepsis, the risk of AKI increased by 31.7% ( OR = 1.317, 95%CI 1.223 ~ 1.418, P < 0.001). CONCLUSION: AKI is a common complication in septic patients hospitalized in the ICU, and hyperuricemia is an independent risk factor for AKI in septic patients.

Cooperative Catalysis between Dual Copper Centers in a Metal-Organic Framework for Efficient Detoxification of Chemical Warfare Agent Simulants.

Chemical warfare agents (CWAs) are among the most lethal chemicals known to humans. Thus, developing multifunctional catalysts for highly efficient detoxification of various CWAs is of great importance. In this work, we developed a robust copper tetrazolate metal-organic framework (MOF) catalyst containing a dicopper unit similar to the coordination geometry of the active sites of natural phosphatase and tyrosinase enzymes. This catalyst aided in phosphate ester bond hydrolysis and hydrogen peroxide decomposition, ultimately achieving high detoxification efficiency against both a nerve agent simulant (diethoxy-phosphoryl cyanide (DECP)) with a half-life of 3.5 min and a sulfur mustard simulant (2-chloroethyl ethyl sulfide (CEES)) with a half-life of 4.5 min, making it competitive with other reported materials. The dicopper sites in ZZU-282 provide versatile binding modes with the substrates, thereby promoting the activation of substrates and enhancing the catalytic efficiency. A combination of postmodified metal exchange control experiments, density functional theory calculations, and catalytic evaluations confirmed that dual Cu sites are the active centers promoting the catalytic reaction. This study offers a new design perspective to achieve advanced catalysts for CWA detoxification.

Efficacy and Safety of Coronary Intervention via Distal Transradial Access (dTRA) in Patients with Low Body Mass Index.

The study aimed to investigate the efficacy and safety of coronary intervention via distal transradial access (dTRA) in patients with low body mass index (BMI). A total of 67 patients with low BMI who underwent coronary intervention, comprising 29 patients via dTRA and 38 patients via conventional transradial access (cTRA), were retrospectively included. There was no significant difference in the puncture success rate between the two groups (dTRA 96.6%, cTRA 97.4%, P=0.846). Compared with the cTRA group, the success rate of one-needle puncture in the dTRA group was lower (51.7% vs. 81.6%, P=0.020). The compression haemostasis time in the dTRA group was shorter than that in the cTRA group (P < 0.001). However, the incidence of radial artery occlusion was lower in the dTRA group than in the cTRA group (4.0% vs. 33.3%, P=0.007). In conclusion, coronary intervention via dTRA was safe and effective in patients with low BMI.

Retrograde Recanalization of Occluded Radial Artery: A Single-Centre Experience and Literature Review.

PURPOSE: Radial artery occlusion (RAO) is one of the common complications after coronary intervention via the conventional radial artery approach. The purpose of the study was to explore the safety and feasibility of retrograde recanalization of the occluded radial artery via a distal radial artery (DRA) approach. METHODS: Combined with the practice of our centre and a literature review, we summarized the procedure of retrograde recanalization of RAO, success rate, and complications. RESULTS: A total of 14 of 15 patients with 15 pieces of occluded radial arteries were successfully recanalized via the DRA in our centre. In the 15 occluded vessels, 11 vessels (73.3%) had total occlusion and 4 vessels (26.7%) had functional occlusion. Four of 15 occluded vessels were acute occlusions. Two acute RAOs were only treated with aspiration via sheath, 11 RAOs with balloon angioplasty, and 2 RAOs with both, respectively. In 6 patients, cardiac catheterization was carried out via the DRA after recanalizing the RAO. A total of 10 studies reporting the results of recanalization of RAO via the DRA were systematically retrieved in the present study. In 3 case series, the number of cases was more than 5, and the success rate of recanalization was more than 85.7%. Two studies reported complications, including dissection in one case, hematoma in 2 cases, and pain in the forearm during angioplasty. CONCLUSIONS: Recanalization of the occluded radial artery via the DRA was safe and effective. When repeat cardiac catheterization was required, recanalization of the RAO and subsequent coronary angiography or intervention through the ipsilateral radial artery approach was feasible.

Safety and efficacy of coronary angiography and percutaneous coronary intervention via distal transradial artery access in the anatomical snuffbox: a single-centre prospective cohort study using a propensity score method.

BACKGROUND: This study investigated the safety and efficacy of coronary angiography (CAG) and percutaneous coronary intervention (PCI) via distal transradial artery access (d-TRA). METHODS: For this single-centre prospective cohort study, a total of 1066 patients who underwent CAG or PCI procedures from September 2019 to November 2020 were included. Patients were divided into two groups: the d-TRA group (346) and the conventional transradial artery access (c-TRA) group (720) based on access site. A total of 342 pairs of patients were successfully matched using propensity score matching (PSM) for subsequent analysis. RESULTS: No significant differences in puncture success rate, procedural method, procedural time, sheath size, contrast dosage or fluoroscopy time were noted between the two groups. The puncture time in the d-TRA group was longer than that in the c-TRA group (P < 0.01), and the procedure success rate was lower than that in the c-TRA group (90.94% vs. 96.49%, P = 0.01). The haemostasis time in the d-TRA group was shorter than that in the c-TRA group (P < 0.01), and the visual analogue scale (VAS) was lower than that in the c-TRA group (P < 0.01). In addition, the prevalence of bleeding and haematoma in the d-TRA group was lower than that in the c-TRA group (1.75% vs. 7.31%, P < 0.01; 0.58% vs. 3.22%, P = 0.01, respectively). No significant difference in the incidence of numbness was noted between the two groups. No other complications were found in two groups. CONCLUSION: d-TRA is as safe and effective as c-TRA for CAG and PCI. It has the advantages of improved comfort and fewer complications. Trail registration Chinese Clinical Trial Registry, ChiCTR1900026519.

Evaluation of Corrosion Damage in Sulfate-Attacked Concrete by CT, Ultrasonic Pulse Velocity Testing and AHP Methods.

Coarse aggregate in concrete is basically free from sulfate corrosion. If the influence of the coarse aggregate in the concrete is not eliminated, the change amount of the concrete ultrasonic pulse velocity value is directly used to evaluate the damage degree of sulfate corrosion in the concrete, and the results are often inaccurate. This paper presents an evaluation method of corrosion damage for the sulfate-attacked concrete by CT, ultrasonic velocity testing and AHP methods. CT was used to extract the coarse aggregate information in the specimen, and the proportion of coarse aggregate on the ultrasonic test line was calculated based on CT image analysis. Then, the correction value of ultrasonic pulse velocity (UPV) of the concrete structure was calculated, and the sulfate corrosion degree of concrete structure was evaluated using the analytic hierarchy process (AHP). The results show that the evaluation method proposed in this paper could more accurately evaluate the corrosion damage in the sulfate-attacked concrete structures, and the evaluation results were more in line with reality.

Slope Micrometeorological Analysis and Prediction Based on an ARIMA Model and Data-Fitting System.

The rapid development of highway engineering has made slope stability an important issue in infrastructure construction. To meet the needs of green vegetation growth, ecological recovery, landscape beautification and the economy, long-term monitoring research on high-slope micrometeorology has important practical significance. Because of that, we designed and created a new slope micrometeorological monitoring and predicting system (SMMPS). We innovatively upgraded the cloud platform system, by adding an ARIMA prediction system and data-fitting system. From regularly sensor-monitored slope micrometeorological factors (soil temperature and humidity, slope temperature and humidity, and slope rainfall), a data-fitting system was used to fit atmospheric data with slope micrometeorological data, the trend of which ARIMA predicted. The slope was protected in time to prevent severe weather damage to the slope vegetation on a large scale. The SMMPS, which upgrades its cloud platform, significantly reduces the cost of long-term monitoring, protects slope stability, and improves the safety of rail and road projects.

Comprehensive Testing of Sulfate Erosion Damage of Concrete Structures and Analysis of Silane Coating Protection Effect.

In order to study the protection performance of silane coating on in-service concrete structures in a sulfate environment, we collect concrete samples in the field to simulate the concrete erosion process by accelerated erosion with wetting-drying cycles. We place the samples into protected, exposed and control groups corresponding to a corrosive environment with silane protection, corrosive environment without protection and general environment for three different service conditions. A combination of ultrasonic velocimetry, CT (Computed Tomography) scan imaging, NMR (Nuclear Magnetic Resonance) pore structure analysis, strength testing and other methods are used to analyze the strength, ultrasonic wave velocity, pore structure and other characteristics of the specimens during sulfate erosion. Based on the test results, the protective effect of silane coating on concrete structures under sulfate attack is quantitatively analyzed, and an index for judging the damage rate of specimens is proposed to quantitatively analyze the protective effect of silane coating. The research results show that the damage of the concrete structure under silane protection in a sulfate-attack environment can be reduced by more than 50%; its integrity damage index and strength damage index are easily affected by the location of local defects, which leads to a decrease in the protection efficiency of the surface silane coating.

CkREV Enhances the Drought Resistance of Caragana korshinskii through Regulating the Expression of Auxin Synthetase Gene CkYUC5.

As a common abiotic stress, drought severely impairs the growth, development, and even survival of plants. Here we report a transcription factor, Caragana korshinskii REVOLUTA(CkREV), which can bidirectionally regulate the expression of the critical enzyme gene CkYUC5 in auxin synthesis according to external environment changes, so as to control the biosynthesis of auxin and further enhance the drought resistance of plants. Quantitative analysis reveals that the expression level of both CkYUC5 and AtYUC5 is down-regulated after C. korshinskii and Arabidopsis thaliana are exposed to drought. Functional verification of CkREV reveals that CkREV up-regulates the expression of AtYUC5 in transgenic A. thaliana under common conditions, while down-regulating it under drought conditions. Meanwhile, the expression of CkYUC5 is also down-regulated in C. korshinskii leaves instantaneously overexpressing CkREV. We apply a dual-luciferase reporter system to discover that CkREV can bind to the promoter of CkYUC5 to regulate its expression, which is further proved by EMSA and Y1H esxperiments. Functional verification of CkREV in C. korshinskii and transgenic A. thaliana shows that CkREV can regulate the expression of CkYUC5 and AtYUC5 in a contrary way, maintaining the equilibrium of plants between growth and drought resisting. CkREV can positively regulate the expression of CkYUC5 to promote auxin synthesis in favor of growth under normal development. However, CkREV can also respond to external signals and negatively regulate the expression of CkYUC5, which inhibits auxin synthesis in order to reduce growth rate, lower water demands, and eventually improve the drought resistance of plants.

Newly Designed Quinazolinone Derivatives as Novel Tyrosinase Inhibitor: Synthesis, Inhibitory Activity, and Mechanism.

We synthesized a series of quinazolinone derivates as tyrosinase inhibitors and evaluated their inhibition constants. We synthesized 2-(2,6-dimethylhepta-1,5-dien-1-yl)quinazolin-4(3H)-one (Q1) from the natural citral. The concentration, which led to 50% activity loss of Q1, was 103 ± 2 µM (IC50 = 103 ± 2 µM). Furthermore, we considered Q1 to be a mixed-type and reversible tyrosinase inhibitor, and determined the KI and KIS inhibition constants to be 117.07 µM and 423.63 µM, respectively. Our fluorescence experiment revealed that Q1 could interact with the substrates of tyrosine and L-DOPA in addition to tyrosinase. Molecular docking studies showed that the binding of Q1 to tyrosinase was driven by hydrogen bonding and hydrophobicity. Briefly, the current study confirmed a new tyrosinase inhibitor, which is expected to be developed into a novel pigmentation drug.

Electropolymerization of Metal Clusters Establishing a Versatile Platform for Enhanced Catalysis Performance.

Atomically precise metal clusters are attractive as highly efficient catalysts, but suffer from continuous efficiency deactivation in the catalytic process. Here, we report the development of an efficient strategy that enhances catalytic performance by electropolymerization (EP) of metal clusters into hybrid materials. Based on carbazole ligand protection, three polymerized metal-cluster hybrid materials, namely Poly-Cu14 cba, Poly-Cu6 Au6 cbz and Poly-Cu6 Ag4 cbz, were prepared. Compared with isolated metal clusters, metal clusters immobilizing on a biscarbazole network after EP significantly improved their electron-transfer ability and long-term recyclability, resulting in higher catalytic performance. As a proof-of-concept, Poly-Cu14 cba was evaluated as an electrocatalyst for reducing nitrate (NO3 - ) to ammonia (NH3 ), which exhibited ≈4-fold NH3 yield rate and ≈2-fold Faraday efficiency enhancement compared to that of Cu14 cba with good durability. Similarly, Poly-Cu6 Au6 cbz showed 10 times higher photocatalytic efficiency towards chemical warfare simulants degradation than the cluster counterpart.

Polygenic interactions with adiposity rebound in the prediction of thelarche.

BACKGROUND: The earliest onset of puberty had shifted downward, which may be due to the role of early growth and development factors in childhood. METHODS: All of 1575 Kindergarten Two (K2) children from Anhui province, China were followed up to elementary school. Girls (n = 342) with available data on AR and breast development were included for this analysis. Polygenic risk score (PRS) was computed based on 17 single nucleotide polymorphisms for early puberty. Accelerate failure time (AFT) model was used to describe thelarche timing by early AR among girls with different polygenic susceptibility. RESULTS: After adjustment for perinatal anthropometric, household income, parental education and prepuberty BMI-Z score, puberty started 4.12-month earlier in early AR girls compared with normal AR girls (TR: 0.96; 95% CI: 0.95, 0.98, p < 0.001). Furthermore, this puberty-accelerating effect was observed among girls with high (6.06-month earlier, TR: 0.94; 95% CI: 0.90, 0.99) and moderate PRS (4.20-month earlier, TR: 0.96; 95% CI: 0.93, 0.98). No similar results were observed in the low PRS groups (TR: 1.00; 95% CI: 0.96, 1.04). CONCLUSIONS: Girls with early AR displayed younger age at thelarche; however, this accelerating effect was only observed among those with genetic susceptibility to early puberty. IMPACT: Early AR plays a more important role in predicting earlier thelarche among girls with high and moderate PRS. This study combined with the hot topics of pubertal-related polygenic risk score (PRS) for pubertal timing to examine the longitudinal association between early AR with accelerated pubertal onset. Our results mean that accelerating growth in the early childhood years after birth might forecast early puberty only among girls with genetic predisposition to early puberty. Prevention strategies and management options should be emphasized to target early childhood to address secular trend for early puberty observed in the past decades in China.

Evaluation of the Uniformity of Protective Coatings on Concrete Structure Surfaces Based on Cluster Analysis.

With the continuous development of urbanization and industrialization in the world, concrete is widely used in various engineering constructions as an engineering material. However, the consequent problem of durability of concrete structures is also becoming increasingly prominent. As an important additional measure, a protective coating can effectively improve the durability of concrete performance. Moreover, the uniformity of the concrete surface coating will directly affect its protective effect. Therefore, we propose a nondestructive inspection and evaluation method of coating uniformity based on infrared imaging and cluster analysis for concrete surface coating uniformity detection and evaluation. Based on the obtained infrared images, a series of processing and analysis of the images were carried out using MATLAB software to obtain the characteristics of the infrared images of the concrete surface. Finally, by extracting the temperature distribution data of the pixel points on the concrete surface, an evaluation method of concrete surface coating uniformity based on a combination of cluster analysis and hierarchical analysis was established. The evaluation results show that the determination results obtained by this method are consistent with the actual situation. This study has a positive contribution to the testing of concrete surface coating uniformity and its evaluation.

Final adult height of children with idiopathic short stature: a multicenter study on GH therapy alone started during peri-puberty.

BACKGROUND: To evaluate the efficacy of GH in improving FAH in ISS children in a multicenter study. METHODS: A real-world observation was carried out. Children with ISS in seven hospitals in China were enrolled. The height gains standard deviation score and the height gain over the target height were evaluated. RESULTS: There were 344 ISS patients (217 boys and 127 girls). The baseline average age of boys and girls was 12.7 and 11.7 years, with bone age of 11.7 and 10.1 years, respectively. The baseline height SDS of boys and girls was - 3.07 and - 2.74, and the FAH SDS was - 1.91 and - 1.38, respectively. Compared with the baseline height SDS, the FAH SDS was significantly increased in both boys and girls (both P = 0.0000). The FAH SDS was the highest (gain by 1.54 SD) in the ≥2y treatment course group. Two hundred eighteen patients (218/344, 63.4%) had a FAH SDS > - 2 SD. Among these patients, girls in the 1-2y treatment course group and ≥ 2y group had a FAH SDS higher than TH SDS. Even in the control group, a spontaneous catch-up growth of 1.16 SD was observed. A multivariate linear regression model was used to analyze the results, with FAH SDS as the dependent variable. It was found that the treatment course and baseline height SDS in the boys' model were statistically significant (P < 0.05), whereas the baseline height SDS and baseline bone age significantly affected the girls' FAH SDS (P < 0.05). CONCLUSIONS: Both girls and boys of ISS improved FAH by GH therapy even if treatments begin over 10 years old and majority of them reached TH. Some peri-puberty ISS will have a spontaneous height gain. We recommend the course of GH treatment more than 2 years for girls, and longer courses for boys.

Development of SSR markers via de novo transcriptome assembly in Akebia trifoliata (Thunb.) Koidz.

Owing to its high nutritive, economic, and medicinal values, Akebia trifoliata has received increased attention, making worthy of being used as a new fruit crop for further domestication and commercialization in China. However, molecular research of A. trifoliata has lagged as investigations of its genomic resources and molecular markers are rare. In this study, a cDNA library of A. trifoliata leaves was sequenced using the Illumina NovaSeq. 6000 sequencing system. In total, 101 417 transcripts, 63 757 unigenes, and 9494 simple sequence repeats were assembled and identified from the transcriptome datasets. The majority of the SSRs were di- and trinucleotide repeats. Length and number of SSR motifs ranged from 15 to 66, and 5 to 48 bp, respectively. Of which, the A/T mononucleotide motif and AG/TC and CT/GA dinucleotide motifs were the most abundant. Furthermore, 100 SSR primers were randomly selected to validate amplification and polymorphism, and 88 A. trifoliata accessions were definitively distinguished by 49 primers. With the Qinling mountains and Huaihe River line as the boundaries, the northern and southern accessions were clustered into different groups, but no clear geographical patterns (city or origin) were observed in the southern accessions. These newly identified molecular markers may provide a foundation for the genetic identification and diversity analysis and marker-assisted selection breeding in species of Akebia.

HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida.

Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.

Preparation of Cellulose/Graphene Oxide Composite Membranes and Their Application in Removing Organic Contaminants in Wastewater.

Cellulose/graphene oxide composite membranes (CGCMs) were prepared using a vacuum-filtration method. The CGCMs were then used as filters to remove organic pollutants from wastewater. It was found that the CGCM filters could efficiently and simultaneously achieve wastewater treatment and adsorbent separation. Their adsorption of Rhodamine B (RhB, an organic dye) varied with varying cellulose/graphene oxide mass ratios. The CGCM obtained at a cellulose/graphene oxide mass ratio of 8:1 exhibited the maximum removal efficiency for RhB. The maximum adsorption capacity of the CGCMs for RhB was found to be 86.4 mg/g. In addition, the CGCMs were easily regenerated and the regenerated CGCMs retained good abilities to remove contaminants, which could be significant for their application in wastewater treatment.