Utility and predictive value of the CRAFITY score in advanced hepatocellular carcinoma treated with transarterial chemoembolization plus tyrosine kinase inhibitors and PD-1 inhibitor.

BACKGROUND: The prognostic significance of the CRAFITY score (CRP and AFP in ImmunoTherapY) has been demonstrated in hepatocellular carcinoma (HCC) patients receiving immunotherapy. The purpose of this study was to investigate the utility and the predictive value of CRAFITY score in HCC after transarterial chemoembolization (TACE) in combination with tyrosine kinase inhibitors (TKIs) and immunotherapy. MATERIALS AND METHODS: Data from patients with advanced HCC treated with TACE plus TKIs and PD-1 inhibitor from January 2019 to June 2022 were collected and analyzed retrospectively. Patients with AFP ≥ 100 ng/mL and those with CRP ≥ 1 mg/dL were assigned a CRAFITY score of 1 point. Patients were divided into three groups according to their CRAFITY score (CRAFITY-low, 0 points; CRAFITY-intermediate, 1 point; and CRAFITY-high, 2 points). The differences in overall survival (OS), progression-free survival (PFS) and adverse events (AEs) were compared among the three groups. Tumor response was evaluated at 3, 6 and 12 months after the first combination treatment. Risk factors for OS and PFS were assessed. RESULTS: A total of 70 patients were included. The patients were assigned CRAFITY scores of 0 points (CRAFITY-low, n = 25 [35.71%]), 1 point (CRAFITY-intermediate, n = 29 [41.42%]), and 2 points (CRAFITY-high, n = 16 [22.81%]). Multivariate analysis showed that lower CRAFITY score was an independent factor for the improved OS (P =.045) and PFS (P <.001). TACE session was also associated with the OS (P =.048) in the multivariate analysis. The CRAFITY-low cohort achieved a higher objective response rate (ORR) at the 3-month evaluation of tumor response. However, there was no significant difference in ORR and disease control rate (DCR) observed at the 6-month follow-up. DCR showed a statistically significant difference among three groups during the 12-month follow-up period. The percentage of patients with protein urea was highest in the CRAFITY-high group. No significance differences were observed in grade ≥ 3 AEs in three groups. CONCLUSION: The CRAFITY score is simple and could be useful for predicting treatment outcomes, tumor response and AEs of the HCC patients receiving TACE plus TKIs and PD-1 inhibitor therapy.

Cardiovascular MRI Reference Ranges for Heart, Aorta, and Pulmonary Artery in Healthy Chinese Children.

BACKGROUND: Cardiovascular magnetic resonance (cardiac MR) reference ranges in Chinese children are lacking. PURPOSE: To establish age- and sex-specific reference ranges for cardiac MR parameters in a cohort of healthy Chinese children. STUDY TYPE: Retrospective. SUBJECTS: One hundred ninety-six healthy children (mean age 9.5 ± 3.6 years, 111 boys). FIELD STRENGTH/SEQUENCE: 1.5 T; balanced steady-state free precession. ASSESSMENT: Biventricular volume and ejection fractions (EF), left atrial (LA) volume, right atrial (RA) area, left ventricular (LV) mass and thickness, aortic root (AR), and main pulmonary artery (MPA) dimensions were measured. Parameters were compared between age groups and sex. The relationships between parameters and age, body mass index (BMI) and body surface area (BSA) were investigated. STATISTICAL TESTS: Independent-samples t tests; Pearson's correlation. A P value <0.05 was considered statistically significant. RESULTS: Generally, boys exhibited greater absolute measurements of LV volume (end-diastolic: 94.4 ± 29.5 vs. 81.3 ± 31.0 mL), LA volume (end-diastolic: 42.6 ± 13.4 vs. 38.0 ± 13.3 mL), RA area (end-diastolic: 11.6 ± 2.5 vs. 10.8 ± 2.6 cm2), LV thickness (base: 4.4 ± 1.1 vs. 3.8 ± 0.9 mm), AR dimensions (annuls: 16.3 ± 2.7 vs. 15.0 ± 2.8 mm), and MPA dimensions (14.3 ± 2.3 vs. 13.1 ± 2.4 mm) than girls did. However, these differences were not observed when the measurements were normalized to BSA (LV volume: 75.3 ± 11.7 vs. 71.9 ± 12.3 mL/m2, P = 0.052; LA volume: 34.8 ± 8.9 vs. 34.5 ± 7.6 mL/m2, P = 0.783; RA area: 9.7 ± 2.3 vs. 10.2 ± 2.3 cm2/m2, P = 0.107; LV thickness: 3.6 ± 0.7 vs. 3.6 ± 0.9 mm/m2, P = 0.990; AR: 13.6 ± 2.7 vs. 14.3 ± 3.4 mm/m2, P = 0.108; MPA: 11.9 ± 2.3 vs. 12.4 ± 2.4 mm/m2, P = 0.118). Boys had greater RV volume (end-diastolic: 98.7 ± 33.5 vs. 82.7 ± 33.1 mL) and LV mass (52.6 ± 20.2 vs. 41.4 ± 16.0 g) compared to girls, irrespective of whether the values were indexed or not for BSA. Additionally, there were significant associations between age, BMI, and BSA with biventricular volume, LA volume, RA area, LV mass and thickness, AR and MPA dimensions in both boys and girls. DATA CONCLUSION: This study suggests reference ranges at 1.5 T for Chinese children. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Delta-radiomics features for predicting the major pathological response to neoadjuvant chemoimmunotherapy in non-small cell lung cancer.

OBJECTIVES: To investigate if delta-radiomics features have the potential to predict the major pathological response (MPR) to neoadjuvant chemoimmunotherapy in non-small cell lung cancer (NSCLC) patients. METHODS: Two hundred six stage IIA-IIIB NSCLC patients from three institutions (Database1 = 164; Database2 = 21; Database3 = 21) who received neoadjuvant chemoimmunotherapy and surgery were included. Patients in Database1 were randomly assigned to the training dataset and test dataset, with a ratio of 0.7:0.3. Patients in Database2 and Database3 were used as two independent external validation datasets. Contrast-enhanced CT scans were obtained at baseline and before surgery. The delta-radiomics features were defined as the relative net change of radiomics features between baseline and preoperative. The delta-radiomics model and pre-treatment radiomics model were established. The performance of Immune-Related Response Evaluation Criteria in Solid Tumors (iRECIST) for predicting MPR was also evaluated. RESULTS: Half of the patients (106/206, 51.5%) showed MPR after neoadjuvant chemoimmunotherapy. For predicting MPR, the delta-radiomics model achieved a satisfying area under the curves (AUCs) values of 0.768, 0.732, 0.833, and 0.716 in the training, test, and two external validation databases, respectively, which showed a superior predictive performance than the pre-treatment radiomics model (0.644, 0.616, 0.475, and 0.608). Compared with iRECIST criteria (0.624, 0.572, 0.650, and 0.466), a mixed model that combines delta-radiomics features and iRECIST had higher AUC values for MPR prediction of 0.777, 0.761, 0.850, and 0.670 in four sets. CONCLUSION: The delta-radiomics model demonstrated superior diagnostic performance compared to pre-treatment radiomics model and iRECIST criteria in predicting MPR preoperatively in neoadjuvant chemoimmunotherapy for stage II-III NSCLC. CLINICAL RELEVANCE STATEMENT: Delta-radiomics features based on the relative net change of radiomics features between baseline and preoperative CT scans serve a vital support tool in accurately identifying responses to neoadjuvant chemoimmunotherapy, which can help physicians make more appropriate treatment decisions. KEY POINTS: • The performances of pre-treatment radiomics model and iRECIST model in predicting major pathological response of neoadjuvant chemoimmunotherapy were unsatisfactory. • The delta-radiomics features based on relative net change of radiomics features between baseline and preoperative CT scans may be used as a noninvasive biomarker for predicting major pathological response of neoadjuvant chemoimmunotherapy. • Combining delta-radiomics features and iRECIST can further improve the predictive performance of responses to neoadjuvant chemoimmunotherapy.

Serum prolactin and gonadal hormones in hemodialysis women: a meta-analysis.

BACKGROUND: A meta-analysis followed by PRISMA 2020 statement was performed aiming to present a whole prolactin and sex hormone profile in hemodialysis women. METHODS: Literatures were searched in PubMed, Cochrane library, Embase, and Web of science before March 11, 2023. Trial sequential analysis (TSA) was performed to test the conclusiveness of this meta-analysis. Egger's test and trim-and-fill analysis was used to test publication bias. We took standardized mean difference (SMD) as pool effect of hormones values including prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and progesterone (P). This study was registered in PROSPERO and the number was CRD42023394503. RESULTS: Twenty-two articles from 13 countries were analyzed. Combining the results of TSA and meta-analysis, we found that compared with healthy control, hemodialysis women had higher PRL, follicular FSH and LH values and lower P levels (PRL: I2 = 87%, SMD 1.24, 95% CI: 0.79-1.69, p < 0.00001; FSH: I2 = 0%, SMD 0.34, 95% CI: 0.13-0.55, p = 0.002; LH: I2 = 39%, SMD 0.64, 95% CI: 0.34-0.93, p < 0.00001; P: I2 = 30%, SMD - 1.62, 95% CI: -2.04 to -1.20, p < 0.00001). What's more, compared with women after renal transplantation, hemodialysis women had higher PRL levels (I2 = 0%, SMD 0.51, 95% CI: 0.25-0.78, p = 0.0001). There was not enough evidence to draw a conclusion on the comparison of hormones between regular and irregular menses hemodialysis women. Egger's test and trim-and-fill analysis didn't show significant publication bias. CONCLUSIONS: Hemodialysis women had higher serum PRL, follicular phase FSH, LH and lower serum P values compared with healthy control. PRL values of hemodialysis women were also higher than that of women after renal transplantation.

A novel N-arachidonoyl-l-alanine-catabolizing strain of Serratia marcescens for the bioremediation of Cd and Cr co-contamination.

Cadmium (Cd) and chromium (Cr) are widespread contaminants with a high risk to the environment and humans. Herein we isolated a novel strain of Serratia marcescens, namely strain S27, from soil co-contaminated with Cd and Cr. This strain showed strong resistance to Cd as well as Cr. S27 cells demonstrated Cd adsorption rate of 45.8% and Cr reduction capacity of 84.4% under optimal growth conditions (i.e., 30 °C, 200 rpm, and pH 7.5). Microscopic characterization of S27 cells revealed the importance of the functional groups C-O-C, C-H-O, C-C, C-H, and -OH, and also indicated that Cr reduction occurred on bacterial cell membrane. Cd(II) and Cr(VI) bioaccumulation on S27 cell surface was mainly in the form of Cd(OH)2 and Cr2O3, respectively. Further, metabolomic analyses revealed that N-arachidonoyl-l-alanine was the key metabolite that promoted Cd and Cr complexation by S27; it primarily promotes γ-linolenic acid (GLA) metabolism, producing siderophores and coordinating with organic acids to enhance metal bioavailability. To summarize, our results suggest that S27 is promising for the bioremediation of environments contaminated with Cd and Cr in tropical regions.

Asymmetric Measurement-Device-Independent Quantum Key Distribution through Advantage Distillation.

Measurement-device-independent quantum key distribution (MDI-QKD) completely closes the security loopholes caused by the imperfection of devices at the detection terminal. Commonly, a symmetric MDI-QKD model is widely used in simulations and experiments. This scenario is far from a real quantum network, where the losses of channels connecting each user are quite different. To adapt such a feature, an asymmetric MDI-QKD model is proposed. How to improve the performance of asymmetric MDI-QKD also becomes an important research direction. In this work, an advantage distillation (AD) method is applied to further improve the performance of asymmetric MDI-QKD without changing the original system structure. Simulation results show that the AD method can improve the secret key rate and transmission distance, especially in the highly asymmetric cases. Therefore, this scheme will greatly promote the development of future MDI-QKD networks.

RPRM deletion preserves hematopoietic regeneration by promoting EGFR-dependent DNA repair and hematopoietic stem cell proliferation post ionizing radiation.

Reprimo (RPRM), a target gene of p53, is a known tumor suppressor. DNA damage induces RPRM, which triggers p53-dependent G2 arrest by inhibiting cyclin B1/Cdc2 complex activation and promotes DNA damage-induced apoptosis. RPRM negatively regulates ataxia-telangiectasia mutated by promoting its nuclear-cytoplasmic translocation and degradation, thus inhibiting DNA damage. Therefore, RPRM plays a crucial role in DNA damage response. Moreover, the loss of RPRM confers radioresistance in mice, which enables longer survival and less severe intestinal injury after radiation exposure. However, the role of RPRM in radiation-induced hematopoietic system injury remains unknown. Herein, utilizing a RPRM-knockout mouse model, we found that RPRM deletion did not affect steady-state hematopoiesis in mice. However, RPRM knockout significantly alleviated radiation-induced hematopoietic system injury and preserved mouse hematopoietic regeneration in hematopoietic stem cells (HSCs) against radiation-induced DNA damage. Further mechanistic studies showed that RPRM loss significantly increased EGFR expression and phosphorylation in HSCs to activate STAT3 and DNA-PKcs, thus promoting HSC DNA repair and proliferation. These findings reveal the critical role of RPRM in radiation-induced hematopoietic system injury, confirming our hypothesis that RPRM may serve as a novel target for radiation protection.

Identification of miRNAs and Target Genes at Key Stages of Sexual Differentiation in Androdioecious Osmanthus fragrans.

Androdioecy is the crucial transition state in the evolutionary direction of hermaphroditism to dioecy, however, the molecular mechanisms underlying the formation of this sex system remain unclear. While popular in China for its ornamental and cultural value, Osmanthus fragrans has an extremely rare androdioecy breeding system, meaning that there are both male and hermaphroditic plants in a population. To unravel the mechanisms underlying the formation of androdioecy, we performed small RNA sequencing studies on male and hermaphroditic O. fragrans. A total of 334 miRNAs were identified, of which 59 were differentially expressed. Functional categorization revealed that the target genes of differentially expressed miRNAs were mainly involved in the biological processes of reproductive development and the hormone signal transduction pathway. We speculated that the miRNA160, miRNA167, miRNA393 and miRNA396 families may influence the sex differentiation in O. fragrans. Overall, our study is the first exploration of miRNAs in the growth and development process of O. fragrans, and is also the first study of androdioecious plants from the miRNA sequencing perspective. The analysis of miRNAs and target genes that may be involved in the sex differentiation process lay a foundation for the ultimate discovery of the androdioecious molecular mechanism in O. fragrans.

Phylogenetic comparison of 5' splice site determination in central spliceosomal proteins of the U1-70K gene family, in response to developmental cues and stress conditions.

Intron-containing genes have the ability to generate multiple transcript isoforms by splicing, thereby greatly expanding the eukaryotic transcriptome and proteome. In eukaryotic cells, precursor mRNA (pre-mRNA) splicing is performed by a mega-macromolecular complex defined as a spliceosome. Among its splicing components, U1 small nuclear ribonucleoprotein (U1 snRNP) is the smallest subcomplex involved in early spliceosome assembly and 5'-splice site recognition. Its central component, named U1-70K, has been extensively characterized in animals and yeast. Very few investigations on U1-70K genes have been conducted in plants, however. To this end, we performed a comprehensive study to systematically identify 115 U1-70K genes from 67 plant species, ranging from algae to angiosperms. Phylogenetic analysis suggested that the expansion of the plant U1-70K gene family was likely to have been driven by whole-genome duplications. Subsequent comparisons of gene structures, protein domains, promoter regions and conserved splicing patterns indicated that plant U1-70Ks are likely to preserve their conserved molecular function across plant lineages and play an important functional role in response to environmental stresses. Furthermore, genetic analysis using T-DNA insertion mutants suggested that Arabidopsis U1-70K may be involved in response to osmotic stress. Our results provide a general overview of this gene family in Viridiplantae and will act as a reference source for future mechanistic studies on this U1 snRNP-specific splicing factor.

SWATH-MS based quantitive proteomics reveal regulatory metabolism and networks of androdioecy breeding system in Osmanthus fragrans.

BACKGROUND: The fragrant flower plant Osmanthus fragrans has an extremely rare androdioecious breeding system displaying the occurrence of males and hermaphrodites in a single population, which occupies a crucial intermediate stage in the evolutionary transition between hermaphroditism and dioecy. However, the molecular mechanism of androdioecy plant is very limited and still largely unknown. RESULTS: Here, we used SWATH-MS-based quantitative approach to study the proteome changes between male and hermaphroditic O. fragrans pistils. A total of 428 proteins of diverse functions were determined to show significant abundance changes including 210 up-regulated and 218 down-regulated proteins in male compared to hermaphroditic pistils. Functional categorization revealed that the differentially expressed proteins (DEPs) primarily distributed in the carbohydrate metabolism, secondary metabolism as well as signaling cascades. Further experimental analysis showed the substantial carbohydrates accumulation associated with promoted net photosynthetic rate and water use efficiency were observed in purplish red pedicel of hermaphroditic flower compared with green pedicel of male flower, implicating glucose metabolism serves as nutritional modulator for the differentiation of male and hermaphroditic flower. Meanwhile, the entire upregulation of secondary metabolism including flavonoids, isoprenoids and lignins seem to protect and maintain the male function in male flowers, well explaining important feature of androdioecy that aborted pistil of a male flower still has a male function. Furthermore, nine selected DEPs were validated via gene expression analysis, suggesting an extra layer of post-transcriptional regulation occurs during O. fragrans floral development. CONCLUSION: Taken together, our findings represent the first SWATH-MS-based proteomic report in androdioecy plant O. fragrans, which reveal carbohydrate metabolism, secondary metabolism and post-transcriptional regulation contributing to the androdioecy breeding system and ultimately extend our understanding on genetic basis as well as the industrialization development of O. fragrans.

Internal Grasper and Magnetic Anchoring Guidance System in Gynecologic Laparoendoscopic Single-site Surgery: A Case Series.

STUDY OBJECTIVE: To evaluate and report preliminary data after the use of an internal grasper and magnetic anchoring guidance system (MAGS) to allow free movement and optimal triangulation in the abdominal cavity during gynecologic laparoendoscopic single-site surgery (LESS). DESIGN: A prospective, single-center case series. SETTING: The First Affiliated Hospital of Xi'an Jiaotong University. PATIENTS: Eighteen female patients underwent MAGS-assisted LESS with an internal grasper. INTERVENTIONS: A single surgeon performed MAGS-assisted LESS on patients with benign gynecologic diseases while documenting operative time, device insertion time, surgeon assessment of technical adaptation, patient-evaluated pain and cosmetic outcomes, adverse events, and blood loss. MEASUREMENTS AND MAIN RESULTS: Eighteen patients underwent transumbilical MAGS-assisted LESS using an internal grasper from November 1, 2019, to December 31, 2019. The mean operative time and insertion time were 98.7 minutes and 1 minute, respectively. The use of MAGS was easily mastered by the surgeon and considered consistently useful in overcoming the limitations of LESS. The patients reported average pain scores of 4.8, 2.3, and 0.5 immediately, 24 hours, and 1 week after surgery, respectively. All patients expressed satisfaction with the postoperative cosmetic results. No serious complications were observed. The mean blood loss was 43.6 mL. CONCLUSION: MAGS-assisted LESS is easy to deploy and use for benign gynecologic disease and seems to result in positive outcomes. Larger randomized controlled trials are warranted.

Global proteome response to Pb(II) toxicity in poplar using SWATH-MS-based quantitative proteomics investigation.

Lead (Pb) toxicity is a growing serious environmental pollution that threatens human health and crop productivity. Poplar, as an important economic and ecological forest species, has the characteristics of fasting growth and accumulating heavy metals, which is a powerful model plant for phytoremediation. Here, a novel label-free quantitative proteomic platform of SWATH-MS was applied to detect proteome changes in poplar seedling roots following Pb treatment. In total 4388 unique proteins were identified and quantified, among which 542 proteins showed significant abundance changes upon Pb(II) exposure. Functional categorizations revealed that differentially expressed proteins (DEPs) primarily distributed in specialized biological processes. Particularly, lignin and flavonoid biosynthesis pathway were strongly activated upon Pb exposure, implicating their potential roles for Pb detoxification in poplar. Furthermore, hemicellulose and pectin related cell wall proteins exhibited increased abundances, where may function as a sequestration reservoir to reduce Pb toxicity in cytoplasm. Simultaneously, up-regulation of glutathione metabolism may serve as a protective role for Pb-induced oxidative damages in poplar. Further correlation investigation revealed an extra layer of post-transcriptional regulation during Pb response in poplar. Overall, our work represents multiply potential regulators in mediating Pb tolerance in poplar, providing molecular targets and strategies for phytoremediation.

Systematic characterization of the branch point binding protein, splicing factor 1, gene family in plant development and stress responses.

BACKGROUND: Among eukaryotic organisms, alternative splicing is an important process that can generate multiple transcripts from one same precursor messenger RNA, which greatly increase transcriptome and proteome diversity. This process is carried out by a super-protein complex defined as the spliceosome. Specifically, splicing factor 1/branchpoint binding protein (SF1/BBP) is a single protein that can bind to the intronic branchpoint sequence (BPS), connecting the 5' and 3' splice site binding complexes during early spliceosome assembly. The molecular function of this protein has been extensively investigated in yeast, metazoa and mammals. However, its counterpart in plants has been seldomly reported. RESULTS: To this end, we conducted a systematic characterization of the SF1 gene family across plant lineages. In this work, a total of 92 sequences from 59 plant species were identified. Phylogenetic relationships of these sequences were constructed, and subsequent bioinformatic analysis suggested that this family likely originated from an ancient gene transposition duplication event. Most plant species were shown to maintain a single copy of this gene. Furthermore, an additional RNA binding motif (RRM) existed in most members of this gene family in comparison to their animal and yeast counterparts, indicating that their potential role was preserved in the plant lineage. CONCLUSION: Our analysis presents general features of the gene and protein structure of this splicing factor family and will provide fundamental information for further functional studies in plants.

Overexpression of phzM contributes to much more production of pyocyanin converted from phenazine-1-carboxylic acid in the absence of RpoS in Pseudomonas aeruginosa.

Pyocyanin produced by Pseudomonas aeruginosa is a key virulence factor that often causes heavy damages to airway and lung in patients. Conversion of phenazine-1-carboxylic acid to pyocyanin involves an extrametabolic pathway that contains two enzymes encoded, respectively, by phzM and phzS. In this study, with construction of the rpoS-deficient mutant, we first found that although phenazine production increased, pyocyanin produced in the mutant YTΔrpoS was fourfold much higher than that in the wild-type strain YT. To investigate this issue, we constructed phzM-lacZ fusion on a vector and on the chromosome. By quantifying ß-galactosidase activities, we confirmed that expression of the phzM was up-regulated when the rpoS gene was inactivated. However, no changes occurred in the expression of phzS and phzH when the rpoS was knocked out. Taken together, overproduction of the SAM-dependent methyltransferase (PhzM) might contribute to the increased pyocyanin in the absence of RpoS in P. aeruginosa.

SWATH-MS-facilitated proteomic profiling of fruit skin between Fuji apple and a red skin bud sport mutant.

BACKGROUND: Apple is one of the most popular fruit crops world-wide and its skin color is an important quality consideration essential for commercial value. However, the strategy on genetic breeding for red skin apple and the genetic basis of skin color differentiation is very limited and still largely unknown. RESULTS: Here, we reported a bud sport mutant of Fuji apple with red skin color and enhanced anthocyanins accumulation. Quantitative SWATH-MS (sequential window acquisition of all theoretical spectra-mass spectrometry) proteomics investigations revealed proteome changes in the apple red skin bud mutation and a total of 451 differentially expressed proteins were identified in apple skin. The mutant showed significantly increased expression levels of photosynthesis-related proteins, stress-related proteins as well as anthocyanins biosynthesis pathway. On the other hand, substantial downregulation of mitogen-activated protein kinase 4 (MAPK4) and mevalonate kinase (MVK) were detected, indicating a promising role for the red skin color development in the mutant. Furthermore, we also hypothesize that a post-transcriptional regulation of the skin color formation occurs in the mutant through the advanced SWATH-MS analysis. CONCLUSION: Our work provides important information on the application of proteomic methods for analysing proteomes changes in Fuji apple and highlights a clade of regulatory proteins potentially contributing for the molecular breeding of fruit skin color.

phz1 contributes much more to phenazine-1-carboxylic acid biosynthesis than phz2 in Pseudomonas aeruginosa rpoS mutant.

Pseudomonas aeruginosa PAO1, a common opportunistic bacterial pathogen, contains two phenazine-biosynthetic operons, phz1 (phzA1 B1 C1 D1 E1 F1 G1 ) and phz2 (phzA2 B2 C2 D2 E2 F2 G2 ). Each of two operons can independently encode a set of enzymes involving in the biosynthesis of phenazine-1-carboxylic acid. As a global transcriptional regulator, RpoS mediates a lot of genes involving secondary metabolites biosynthesis in many bacteria. In an other previous study, it was reported that RpoS deficiency caused overproduction of pyocyanin, a derivative of phenazine-1-carboxylic acid in P. aeruginosa PAO1. But it is not known how RpoS mediates the expression of each of two phz operons and modulates phenazine-1-carboxylic acid biosynthesis in detail. In this study, by deleting the rpoS gene in the mutant PNΔphz1 and the mutant PNΔphz2, we found that the phz1 operon contributes much more to phenazine-1-carboxylic acid biosynthesis than the phz2 operon in the absence of RpoS. With the construction of the translational and transcriptional fusion vectors with the truncated lacZ reporter gene, we demonstrated that RpoS negatively regulates the expression of phz1 and positively controls the expression of phz2, and the regulation of phenazine-1-carboxylic acid biosynthesis mediated by RopS occurs at the posttranscriptional level, not at the transcriptional level. Obviously, two copies of phz operons and their differential expression mediated by RpoS might help P. aeruginosa adapt to its diverse environments and establish infection in its hosts.

Biodegradation of phthalic acid esters (PAEs) by Janthinobacterium sp. strain E1 under stress conditions.

Phthalates esters (PAEs) are a kind of polymeric material additives widely been added into plastics to improve products' flexibility. It can easily cause environmental pollution which are hazards to public health. In this study, we isolated an efficient PAEs degrading strain, Janthinobacterium sp. E1, and determined its degradation effect of di-2-ethylhexyl phthalate (DEHP) under stress conditions. Strain E1 showed an obvious advantage in pollutants degradation under various environmental stress conditions. Degradation halo clearly occurred around the colony of strain E1 on agar plate supplemented with triglyceride. Strain E1's esterase is a constitutively expressed intracellular enzyme. The esterase purified from strain E1 showed a higher catalytic effect on short-chain PAEs than long-chain PAEs. The input of DEHP, DBP (dibutyl phthalate) and DMP (dimethyl phthalate) into the tested soil did not change the species composition of soil prokaryotic community, but altered the dominant species in specific environmental conditions. And the community diversity and richness decreased to a certain extent. However, the diversity and richness of the microbial community were improved after the contaminated soil was treated with the strain E1. Our results also suggested that strain E1 exhibited a tremendous potential in environmental bioremediation in the real environment, which provides a new insight into the elimination of the pollutants contamination in the urban environment.