Distinct epigenetic modulation of differentially expressed genes in the adult mouse brain following prenatal exposure to low-dose bisphenol A.

Bisphenol A (BPA) is a common component in the manufacture of daily plastic consumer goods. Recent studies have suggested that prenatal exposure to BPA can increase the susceptibility of offspring to mental illness, although the underlying mechanisms remain unclear. In this study, we performed transcriptomic and epigenomic profiling in the adult mouse brain following prenatal exposure to low-dose BPA. We observed a sex-specific transcriptional dysregulation in the cortex, with more significant differentially expressed genes was observed in adult cortex from male offspring. Moreover, the upregulated genes primarily influenced neuronal functions, while the downregulated genes were significantly associated with energy metabolism pathways. More evidence supporting impaired mitochondrial function included a decreased ATP level and a reduced number of mitochondria in the cortical neuron of the BPA group. We further investigated the higher-order chromatin regulatory patterns of DEGs by incorporating published Hi-C data. Interestingly, we found that upregulated genes exhibited more distal interactions with multiple enhancers, while downregulated genes displayed relatively short-range interactions among adjacent genes. Our data further revealed decreased H3K9me3 signal on the distal enhancers of upregulated genes, whereas increased DNA methylation and H3K27me3 signals on the promoters of downregulated genes. In summary, our study provides compelling evidence for the potential health risks associated with prenatal exposure to BPA, and uncovers sex-specific transcriptional changes with a complex interplay of multiple epigenetic mechanisms.

Interaction between Oligodendrocytes and Interneurons in Brain Development and Related Neuropsychiatric Disorders.

A variety of neurological and psychiatric disorders have recently been shown to be highly associated with the abnormal development and function of oligodendrocytes (OLs) and interneurons. OLs are the myelin-forming cells in the central nervous system (CNS), while interneurons are important neural types gating the function of excitatory neurons. These two types of cells are of great significance for the establishment and function of neural circuits, and they share similar developmental origins and transcriptional architectures, and interact with each other in multiple ways during development. In this review, we compare the similarities and differences in these two cell types, providing an important reference and further revealing the pathogenesis of related brain disorders.

Transcriptomic profiling of the developing brain revealed cell-type and brain-region specificity in a mouse model of prenatal stress.

BACKGROUND: Prenatal stress (PS) is considered as a risk factor for many mental disorders. PS-induced transcriptomic alterations may contribute to the functional dysregulation during brain development. Here, we used RNA-seq to explore changes of gene expression in the mouse fetal brain after prenatal exposure to chronic unpredictable mild stress (CUMS). RESULTS: We compared the stressed brains to the controls and identified groups of significantly differentially expressed genes (DEGs). GO analysis on up-regulated DEGs revealed enrichment for the cell cycle pathways, while down-regulated DEGs were mostly enriched in the neuronal pathways related to synaptic transmission. We further performed cell-type enrichment analysis using published scRNA-seq data from the fetal mouse brain and revealed cell-type-specificity for up- and down-regulated DEGs, respectively. The up-regulated DEGs were highly enriched in the radial glia, while down-regulated DEGs were enriched in different types of neurons. Cell deconvolution analysis further showed altered cell fractions in the stressed brain, indicating accumulation of neuroblast and impaired neurogenesis. Moreover, we also observed distinct brain-region expression pattern when mapping DEGs onto the developing Allen brain atlas. The up-regulated DEGs were primarily enriched in the dorsal forebrain regions including the cortical plate and hippocampal formation. Surprisingly, down-regulated DEGs were found excluded from the cortical region, but highly expressed on various regions in the ventral forebrain, midbrain and hindbrain. CONCLUSION: Taken together, we provided an unbiased data source for transcriptomic alterations of the whole fetal brain after chronic PS, and reported differential cell-type and brain-region vulnerability of the developing brain in response to environmental insults during the pregnancy.

Predictive performance of the perivascular fat attenuation index for interventional antegrade percutaneous coronary intervention for chronic total occlusion.

OBJECTIVES: This study aimed to investigate the association between the perivascular fat attenuation index (FAI) and the success of the antegrade percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). METHODS: This study evaluated patients with only one CTO lesion observed on conventional coronary angiography (CAG) who underwent coronary computed tomography angiography (CCTA) < 1 month before CAG, from 2018 to 2019. The clinical data, CCTA-based CTO lesion morphologic characteristics, and perivascular FAI of CTO lesions were recorded and analysed. RESULTS: In total, 156 patients with CTOs were enrolled in this study. Successful antegrade PCI (A-PCI) was achieved in 105 CTO lesions (67.3%). The perivascular FAI of the failed A-PCI group was significantly lower than the successful A-PCI group (-84.76 ± 10.44 Hounsfield unit (HU) vs. -67.54 ± 9.94 HU; p < 0.001), and the cut-off value determined by the receiver operating characteristic (ROC) curve was -77.50 HU. Multivariable analysis revealed no statistical significance in the clinical data, FAI ≤ -77.50 HU (odds ratio (OR): 33.96), negative remodeling (OR: 4.36), severe calcification degree (OR: 4.43) and occlusion length ≥ 20.25 mm (OR: 3.89) were independent predictors of A-PCI failure. The prediction performance of combining the three morphologic characteristics (severe calcification, occlusion length ≥ 20.25 mm, and negative remodeling) with FAI ≤ -77.50 HU was better than that of the three morphologic characteristics alone (0.93 versus 0.77, p < 0.001). CONCLUSIONS: As a non-invasive index for detecting coronary inflammation, FAI complements indicators based on coronary CTA well and may be helpful for choosing appropriate interventional strategies. KEY POINTS: • Perivascular FAI of CTO was significantly higher in the failed A-PCI group. • The combination of FAI with other morphological predictors showed higher predictive performance of failed A-PCI for CTOs. • FAI is a good complement to indicators based on coronary CTA.

luxS contributes to intramacrophage survival of Streptococcus agalactiae by positively affecting the expression of fruRKI operon.

The LuxS quorum sensing system is a widespread system employed by many bacteria for cell-to-cell communication. The luxS gene has been demonstrated to play a crucial role in intramacrophage survival of piscine Streptococcus agalactiae, but the underlying mechanism remains largely unknown. In this study, transcriptome analysis, followed by the luxS gene deletion and subsequent functional studies, confirmed that impaired bacterial survival inside macrophages due to the inactivation of luxS was associated with reduced transcription of the fruRKI operon, encoding the fructose-specific phosphotransferase system. Further, luxS was determined not to enhance the transcription of fruRKI operon by binding its promoter, but to upregulate the expression of this operon via affecting the binding ability of catabolite control protein A (CcpA) to the catabolite responsive element (cre) in the promoter of fruRKI. Collectively, our study identifies a novel and previously unappreciated role for luxS in bacterial intracellular survival, which may give a more thorough understanding of the immune evasion mechanism in S. agalactiae.

Qualitative and Quantitative Determination of Decoquinate in Chicken Tissues by Gas Chromatography Tandem Mass Spectrometry.

A novel precolumn derivatization-GC-MS/MS method was developed for the determination of decoquinate residues in chicken tissues (muscle, liver, and kidney). The samples were extracted and purified by liquid-liquid extraction combined with solid-phase extraction and derivatized with acetic anhydride and pyridine. The recovery rates for decoquinate were 77.38~89.65%, and the intra-day and inter-day RSDs were 1.63~5.74% and 2.27~8.06%, respectively. The technique parameters meet the necessities for veterinary drug residue detection in China, the US, and the EU. Finally, the method was applied to analyze tissues of 60 chickens bought from a neighborhood supermarket, and solely one sample of chicken muscle contained 15.6 µg/kg decoquinate residue.

Predicting reintervention after thoracic endovascular aortic repair of Stanford type B aortic dissection using machine learning.

OBJECTIVES: To construct models for predicting reintervention after thoracic endovascular aortic repair (TEVAR) of Stanford type B aortic dissection (TBAD). METHODS: A total of 192 TBAD patients who underwent TEVAR were included; 68 (35.4%) had indications for reintervention. Clinical characteristics, aorta characteristics on pre- and postoperative computed tomography angiography, and aorta characteristics on immediate postoperative aortic digital subtraction angiography were collected. The least absolute shrinkage and selection operator (LASSO) regression was applied to identify the risk factors for reintervention. Eight classifiers were used for modeling. The models were trained on 100 train-validation random splits with a ratio of 2:1. The performance was evaluated by the receiver operating characteristic curve. RESULTS: Seven predictors of reintervention were identified, including maximum false lumen diameter, aortic diameter measured at the level of approximately 15 mm distal to the left subclavian artery, aortic diameter measured at the level of the diaphragm, false lumen diameter measured at the level of the celiac artery, number of bare-metal and covered stents, number of bare-metal stents, and residual perfusion of the false lumen. Logistic regression (LR) yielded the highest performance, with an area under the curve of 0.802. A nomogram built for clinical use showed good calibration. The cutoff value for dividing patients into low- and high-risk subgroups was 0.413. Kaplan-Meier curves showed that the overall survival of high-risk patients was significantly shorter than that of low-risk patients (both p < 0.05). CONCLUSION: Our nomogram could predict the reintervention after TEVAR in patients with TBAD, which may facilitate patient selection and surveillance strategies. KEY POINTS: • Seven risk factors of reintervention after TEVAR of TBAD were identified for modeling. • Logistic regression performed best in predicting reintervention with an AUC of 0.802. • Patients with a high risk of reintervention had shorter OS than those with a low risk.

Concurrent Determination of Tigecycline, Tetracyclines and Their 4-Epimer Derivatives in Chicken Muscle Isolated from a Reversed-Phase Chromatography System Using Tandem Mass Spectrometry.

A quantitative and qualitative method using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) detection approach was developed and validated for the analysis of tigecycline, four tetracyclines and their three 4-epimer derivatives in chicken muscle. Samples were extracted repeatedly with 0.1 mol/L Na2EDTA-McIlvaine buffer solution. After vortexing, centrifugation, solid-phase extraction, evaporation and reconstitution, the aliquots were separated using a C8 reversed-phase column (50 mm × 2.1 mm, 5 µm) with a binary solvent system consisting of methanol and 0.01 mol/L trichloroacetic acid aqueous solution. The typical validation parameters were evaluated in accordance with the acceptance criteria detailed in the guidelines of the EU Commission Decision 2002/657/EC and the U.S. Food and Drug Administration Bioanalytical Method Validation 05/24/18. The matrix-matched calibration curve was linear over the concentration range from the limit of quantitation (LOQ) to 400 µg/kg for doxycycline, and the calibration graphs for tetracycline, chlortetracycline, oxytetracycline, their 4-epimer derivatives and tigecycline showed a good linear relationship within the concentration range from the LOQ to 200 µg/kg. The limits of detection (LODs) for the eight targets were in the range of 0.06 to 0.09 µg/kg, and the recoveries from the fortified blank samples were in the range of 89% to 98%. The within-run precision and between-run precision, which were expressed as the relative standard deviations, were less than 5.0% and 6.9%, respectively. The applicability was successfully demonstrated through the determination of residues in 72 commercial chicken samples purchased from different sources. This approach provides a novel option for the detection of residues in animal-derived food safety monitoring.

The TonB system in Aeromonas hydrophila NJ-35 is essential for MacA2B2 efflux pump-mediated macrolide resistance.

The TonB system is generally considered as an energy transporting device for the absorption of nutrients. Our recent study showed that deletion of this system caused a significantly increased sensitivity of Aeromonas hydrophila to the macrolides erythromycin and roxithromycin, but had no effect on other classes of antibiotics. In this study, we found the sensitivity of ΔtonB123 to all macrolides tested revealed a 8- to 16-fold increase compared with the wild-type (WT) strain, but this increase was not related with iron deprivation caused by tonB123 deletion. Further study demonstrated that the deletion of tonB123 did not damage the integrity of the bacterial membrane but did hinder the function of macrolide efflux. Compared with the WT strain, deletion of macA2B2, one of two ATP-binding cassette (ABC) types of the macrolide efflux pump, enhanced the sensitivity to the same levels as those of ΔtonB123. Interestingly, the deletion of macA2B2 in the ΔtonB123 mutant did not cause further increase in sensitivity to macrolide resistance, indicating that the macrolide resistance afforded by the MacA2B2 pump was completely abrogated by tonB123 deletion. In addition, macA2B2 expression was not altered in the ΔtonB123 mutant, indicating that any influence of TonB on MacA2B2-mediated macrolide resistance was at the pump activity level. In conclusion, inactivation of the TonB system significantly compromises the resistance of A. hydrophila to macrolides, and the mechanism of action is related to the function of MacA2B2-mediated macrolide efflux.

Myocardial Mechanics Parameters That Predict Left Ventricular Outflow Tract Obstruction in Patients With Hypertrophic Cardiomyopathy: A Cardiovascular Magnetic Resonance Feature Tracking Analysis.

OBJECTIVE: To identify left ventricular (LV) myocardial mechanics predictors of LV outflow tract obstruction (LVOTO) in patients with hypertrophic cardiomyopathy (HCM). METHODS: Thirty-nine adults with HCM and 21 controls underwent cardiovascular magnetic resonance. The feature tracking (FT) analysis results of HCM patients with and without LVOTO and controls were compared. RESULTS: Global radial strain measured on the short-axis slice (GRS-SAX) (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.15; P < 0.01), global longitudinal strain measured on the long-axis slice (GLS-LAX) (OR, 1.81; 95% CI, 1.21-2.73; P < 0.01) and GRS measured on the long-axis slice (GRS-LAX) (OR, 1.07; 95% CI, 1.01-1.13; P = 0.02) were independent predictors of LVOTO. The combination of GRS-SAX plus GLS-LAX and GRS-LAX showed great discriminatory power for identifying LVOTO with an area under the receiver operating characteristic curve value of 0.91 (95% CI: 0.81-1.00). CONCLUSIONS: In adult HCM patients, GRS-SAX, GLS-LAX, and GRS-LAX were independent predictors of LVOTO. The combination of GRS-SAX plus GLS-LAX and GRS-LAX showed great discriminatory power for identifying LVOTO.

Isolation and characterization of bacteriophages against virulent Aeromonas hydrophila.

BACKGROUND: Aeromonas hydrophila is an important water-borne pathogen that leads to a great economic loss in aquaculture. Along with the abuse of antibiotics, drug-resistant strains rise rapidly. In addition, the biofilms formed by this bacterium limited the antibacterial effect of antibiotics. Bacteriophages have been attracting increasing attention as a potential alternative to antibiotics against bacterial infections. RESULTS: Five phages against pathogenic A. hydrophila, named N21, W3, G65, Y71 and Y81, were isolated. Morphological analysis by transmission electron microscopy revealed that phages N21, W3 and G65 belong to the family Myoviridae, while Y71 and Y81 belong to the Podoviridae. These phages were found to have broad host spectra, short latent periods and normal burst sizes. They were sensitive to high temperature but had a wide adaptability to the pH. In addition, the phages G65 and Y81 showed considerable bacterial killing effect and potential in preventing formation of A. hydrophila biofilm; and the phages G65, W3 and N21 were able to scavenge mature biofilm effectively. Phage treatments applied to the pathogenic A. hydrophila in mice model resulted in a significantly decreased bacterial loads in tissues. CONCLUSIONS: Five A. hydrophila phages were isolated with broad host ranges, low latent periods, and wide pH and thermal tolerance. And the phages exhibited varying abilities in controlling A. hydrophila infection. This work presents promising data supporting the future use of phage therapy.

Development and validation of a Web-based malignancy risk-stratification system of thyroid nodules.

OBJECTIVES: Previous publications on risk-stratification systems for malignant thyroid nodules were based on conventional ultrasound only. We aimed to develop a practical and simplified prediction model for categorizing the malignancy risk of thyroid nodules based on clinical data, biochemical data, conventional ultrasound and real-time elastography. DESIGN: Retrospective cohort study. PATIENTS: A total of 2818 patients (1890 female, mean age, 45.5 ± 13.2 years) with 2850 thyroid nodules were retrospectively evaluated between April 2011 and October 2016. 26.8% nodules were malignant. MEASUREMENTS: We used a randomly divided sample of 80% of the nodules to perform a multivariate logistic regression analysis. Cut-points were determined to create a risk-stratification scoring system. Patients were classified as having low, moderate and high probability of malignancy according to their scores. We validated the models to the remaining 20% of the nodules. The area under the curve (AUC) was used to evaluate the discrimination ability of the systems. RESULTS: Ten variables were selected as predictors of malignancy. The point-based scoring systems with and without elasticity score achieved similar AUCs of 0.916 (95% confidence interval [CI]: 0.885-0.948) and 0.906 (95% CI: 0.872-0.941) when validated. Malignancy risk was segmented from 0% to 100.0% and was positively associated with an increase in risk scores. We then developed a Web-based risk-stratification system of thyroid nodules (http: thynodscore.com). CONCLUSION: A simple and reliable Web-based risk-stratification system could be practically used in stratifying the risk of malignancy in thyroid nodules.

Machine-learning based MRI radiomics models for early detection of radiation-induced brain injury in nasopharyngeal carcinoma.

BACKGROUND: Early radiation-induced temporal lobe injury (RTLI) diagnosis in nasopharyngeal carcinoma (NPC) is clinically challenging, and prediction models of RTLI are lacking. Hence, we aimed to develop radiomic models for early detection of RTLI. METHODS: We retrospectively included a total of 242 NPC patients who underwent regular follow-up magnetic resonance imaging (MRI) examinations, including contrast-enhanced T1-weighted and T2-weighted imaging. For each MRI sequence, four non-texture and 10,320 texture features were extracted from medial temporal lobe, gray matter, and white matter, respectively. The relief and 0.632 + bootstrap algorithms were applied for initial and subsequent feature selection, respectively. Random forest method was used to construct the prediction model. Three models, 1, 2 and 3, were developed for predicting the results of the last three follow-up MRI scans at different times before RTLI onset, respectively. The area under the curve (AUC) was used to evaluate the performance of models. RESULTS: Of the 242 patients, 171 (70.7%) were men, and the mean age of all the patients was 48.5 ± 10.4 years. The median follow-up and latency from radiotherapy until RTLI were 46 and 41 months, respectively. In the testing cohort, models 1, 2, and 3, with 20 texture features derived from the medial temporal lobe, yielded mean AUCs of 0.830 (95% CI: 0.823-0.837), 0.773 (95% CI: 0.763-0.782), and 0.716 (95% CI: 0.699-0.733), respectively. CONCLUSION: The three developed radiomic models can dynamically predict RTLI in advance, enabling early detection and allowing clinicians to take preventive measures to stop or slow down the deterioration of RTLI.

Prediction of pulmonary pressure after Glenn shunts by computed tomography-based machine learning models.

OBJECTIVES: This study aimed to develop non-invasive machine learning classifiers for predicting post-Glenn shunt patients with low and high risks of a mean pulmonary arterial pressure (mPAP) > 15 mmHg based on preoperative cardiac computed tomography (CT). METHODS: This retrospective study included 96 patients with functional single ventricle who underwent a bidirectional Glenn procedure between November 1, 2009, and July, 31, 2017. All patients underwent post-procedure CT, followed by cardiac catheterization. Overall, 23 morphologic parameters were manually extracted from cardiac CT images for each patient. The Mann-Whitney U or chi-square test was applied to select the most significant predictors. Six machine learning algorithms including logistic regression, Naive Bayes, random forest (RF), linear discriminant analysis, support vector machine, and K-nearest neighbor were used for modeling. These algorithms were independently trained on 100 train-validation random splits with a 3:1 ratio. Their average performance was evaluated by area under the curve (AUC), accuracy, sensitivity, and specificity. RESULTS: Seven CT morphologic parameters were selected for modeling. RF obtained the best performance, with mean AUC of 0.840 (confidence interval [CI] 0.832-0.850) and 0.787 (95% CI 0.780-0.794); sensitivity of 0.815 (95% CI 0.797-0.833) and 0.778 (95% CI 0.767-0.788), specificity of 0.766 (95% CI 0.748-0.785) and 0.746 (95% CI 0.735-0.757); and accuracy of 0.782 (95% CI 0.771-0.793) and 0.756 (95% CI 0.748-0.764) in the training and validation cohorts, respectively. CONCLUSIONS: The CT-based RF model demonstrates a good performance in the prediction of mPAP, which may reduce the need for right heart catheterization in post-Glenn shunt patients with suspected mPAP > 15 mmHg. KEY POINTS: • Twenty-three candidate descriptors were manually extracted from cardiac computed tomography images, and seven of them were selected for subsequent modeling. • The random forest model presents the best predictive performance for pulmonary pressure among all methods. • The computed tomography-based machine learning model could predict post-Glenn shunt pulmonary pressure non-invasively.

Prognostic value of the radiomics-based model in progression-free survival of hypopharyngeal cancer treated with chemoradiation.

PURPOSE: To develop a radiomics-based model to stratify the risk of early progression (local/regional recurrence or metastasis) among patients with hypopharyngeal cancer undergoing chemoradiotherapy and modify their pretreatment plans. MATERIALS AND METHODS: We randomly assigned 113 patients into two cohorts: training (n = 80) and validation (n = 33). The radiomic significant features were selected in the training cohort using least absolute shrinkage and selection operator and Akaike information criterion methods, and they were used to build the radiomic model. The concordance index (C-index) was applied to evaluate the model's prognostic performance. A Kaplan-Meier analysis and the log-rank test were used to assess risk stratification ability of models in predicting progression. A nomogram was plotted to predict individual risk of progression. RESULTS: Composed of four significant features, the radiomic model showed good performance in stratifying patients into high- and low-risk groups of progression in both the training and validation cohorts (log-rank test, p = 0.00016, p = 0.0063, respectively). Peripheral invasion and metastasis were selected as significant clinical variables. The combined radiomic-clinical model showed good discriminative performance, with C-indices 0.804 (95% confidence interval (CI), 0.688-0.920) and 0.756 (95% CI, 0.605-0.907) in the training and validation cohorts, respectively. The median progression-free survival (PFS) in the high-risk group was significantly shorter than that in the low-risk group in the training (median PFS, 9.5 m and 19.0 m, respectively; p [log-rank] < 0.0001) and validation (median PFS, 11.3 m and 22.5 m, respectively; p [log-rank] = 0.0063) cohorts. CONCLUSIONS: A radiomics-based model was established to predict the risk of progression in hypopharyngeal cancer with chemoradiotherapy. KEY POINTS: • Clinical information showed limited performance in stratifying the risk of progression among patients with hypopharyngeal cancer. • Imaging features extracted from CECT and NCCT images were independent predictors of PFS. • We combined significant features and valuable clinical variables to establish a nomogram to predict individual risk of progression.

Identification of a new effector-immunity pair of Aeromonas hydrophila type VI secretion system.

The type VI secretion system (T6SS) is a multiprotein weapon that kills eukaryotic predators or prokaryotic competitors by delivering toxic effectors. Despite the importance of T6SS in bacterial environmental adaptation, it is still challenging to systematically identify T6SS effectors because of their high diversity and lack of conserved domains. In this report, we discovered a putative effector gene, U876-17730, in the whole genome of Aeromonas hydrophila NJ-35 based on the reported conservative domain DUF4123 (domain of unknown function), with two cognate immunity proteins encoded downstream. Phylogenetic tree analysis of amino acids indicates that AH17730 belongs to the Tle1 (type VI lipase effector) family, and therefore was named Tle1AH. The deletion of tle1AH resulted in significantly decreased biofilm formation, antibacterial competition ability and virulence in zebrafish (Danio rerio) when compared to the wild-type strain. Only when the two immunity proteins coexist can bacteria protect themselves from the toxicity of Tle1AH. Further study shows that Tle1AH is a kind of phospholipase that possesses a conserved lipase motif, Gly-X-Ser-X-Gly (X is for any amino acid). Tle1AH is secreted by T6SS, and this secretion requires its interaction with an associated VgrG (valine-glycine repeat protein G). In conclusion, we identified a T6SS effector-immunity pair and verified its function, which lays the foundation for future research on the role of T6SS in the pathogenic mechanism of A. hydrophila.

Role of luxS in immune evasion and pathogenicity of piscine Streptococcus agalactiae is not dependent on autoinducer-2.

luxS-mediated autoinducer 2 (AI-2)-dependent quorum sensing (QS) has been demonstrated to affect many bacterial phenotypes, including virulence. Streptococcus agalactiae harbors a functional luxS gene required for the biosynthesis of AI-2. In this study, we investigated the regulation effect and mechanism of the luxS/AI-2 QS system in the pathogenicity of the piscine S. agalactiae strain GD201008-001. We found that inactivation of luxS caused a marked decrease in biofilm formation, hemolytic activity, antiphagocytosis and intracellular survival of S. agalactiae. Except for hemolytic activity, the altered phenotypes due to the luxS deletion were AI-2-independent. Further investigation indicated that high levels of the proinflammatory cytokines IL-1ß and IL-6 could be induced in macrophages co-incubated with the luxS deletion mutant and synthetic AI-2, single or combined. Also, the results of tilapia infection showed that inactivation of luxS significantly decreased the virulence of S. agalactiae but upregulated the expression of cytokines in spleens and brains. Increased proinflammatory effects of the luxS mutant were restored in the luxS complemented strain but could not be restored by AI-2 addition. All the findings suggest that luxS is involved in virulence-associated phenotypes and immunological evasion of S. agalactiae, and furthermore, this involvement is mostly AI-2-independent. This study will provide valuable insights into our understanding of the role of the LuxS/AI-2 QS system in the pathogenesis of S. agalactiae.

Intra-arterial chemotherapy as primary or secondary treatment for infants diagnosed with advanced retinoblastoma before 3 months of age.

BACKGROUND: To evaluate the safety and efficacy of intra-arterial chemotherapy (IAC) for the primary or secondary treatment of infants diagnosed with advanced retinoblastoma before 3 months of age. METHODS: This single-center retrospective study included 39 infants (42 eyes) aged ≤3 months who were diagnosed with unilateral or bilateral advanced intraocular retinoblastoma (group D and E eyes) and received IAC as primary or secondary treatment between June 2012 and February 2017. Based on each patient's therapeutic history and response to chemotherapeutic drugs, melphalan, topotecan, and/or carboplatin were used for IAC. The main outcomes included the technical success rate for IAC, survival rates, and adverse events. RESULTS: In total, 29 and 13 eyes received IAC as primary and secondary treatments, respectively. Catheterization was successful in 136 of 137 procedures. All eyes in the secondary IAC group had previously received intravenous chemotherapy. The mean number of IAC sessions for each eye was 3 (range, 2-6). The 2-year ocular survival rates were 80.7% (95% confidence interval [CI], 58.9-91.7) in the primary IAC group and 91.7% (95% CI, 53.9-98.8) in the secondary IAC group. During the follow-up period, 1 patient with unilateral disease (group E) developed extraocular disease and died. The 2-year recurrence-free survival rates in the primary and secondary IAC groups were 71.9% (95% CI, 49.4-85.7) and 75.0% (95% CI, 40.8-91.2), respectively. During each catheterization procedure, the main complications included eyelid erythema (2.4%), fundus hemorrhage (11.9%), myelosuppression (7.7%), transient vomiting and hair loss (2.6%), and transient pancytopenia (2.6%). Prolonged complications included phthisis bulbi (19.0%), vision loss (19.0%), poor vision (9.5%), and cataract (2.4%). There was no case of stroke, neurological impairment, secondary malignant tumor, or metastasis. CONCLUSIONS: Our findings suggest that IAC, whether primary or secondary, is effective and fairly safe for the management of advanced retinoblastoma in infants aged < 3 months. However, adverse events related to intra-arterial injection and the visual outcomes cannot be neglected and require further investigation.

Diverse effects of nitric oxide reductase NorV on Aeromonas hydrophila virulence-associated traits under aerobic and anaerobic conditions.

NorV has been known to be an anaerobic nitric oxide reductase associated with nitric oxide (NO) detoxification. Recently, we showed that the norV gene of Aeromonas hydrophila was highly upregulated after co-culturing with Tetrahymena thermophila. Here, we demonstrated that the transcription and expression levels of norV were upregulated in a dose-dependent manner after exposure to NO under aerobic and anaerobic conditions. To investigate the roles of norV in resisting predatory protists and virulence of A. hydrophila, we constructed the norV gene-deletion mutant (ΔnorV). Compared to the wild type, the ΔnorV mutant showed no significant difference in growth at various NO concentrations under aerobic conditions but significantly stronger NO-mediated growth inhibition under anaerobic conditions. The deletion of norV exhibited markedly decreased cytotoxicity, hemolytic and protease activities under aerobic and anaerobic conditions. Also, the hemolysin co-regulated protein (Hcp) in the ΔnorV mutant showed increased secretion under aerobic conditions but decreased secretion under anaerobic conditions as compared to the wild-type. Moreover, the inactivation of norV led to reduced resistance to predation by T. thermophila, decreased survival within macrophages and highly attenuated virulence in zebrafish. Our data indicate a diverse role for norV in the expression of A. hydrophila virulence-associated traits that is not completely dependent on its function as a nitric oxide reductase. This study provides insights into an unexplored area of NorV, which will contribute to our understanding of bacterial pathogenesis and the development of new control strategies for A. hydrophila infection.

Roles of three TonB systems in the iron utilization and virulence of the Aeromonas hydrophila Chinese epidemic strain NJ-35.

The TonB system functions in iron transport and has been identified in certain Gram-negative bacteria. Recently, we reported three TonB systems in the Aeromonas hydrophila Chinese epidemic strain NJ-35, but the functions of these systems have not been thoroughly elucidated to date. In this study, we investigated the role of these TonB systems in A. hydrophila iron utilization and virulence. We found that tonB1 and tonB2 were preferentially transcribed in iron-chelated conditions, where gene expression levels were approximately 8- and 68-fold higher compared with iron-rich conditions, respectively; tonB3 was consistently transcribed at a low level under iron-repleted and iron-depleted conditions. Only the TonB2 system was required to utilize iron-binding proteins. The tonB123 mutant showed increased susceptibility to erythromycin and roxithromycin. In addition, all three tonB genes were involved in A. hydrophila virulence in zebrafish, and various phenotypes associated with environmental survival were changed with varying degrees in each tonB mutant. TonB2 plays a relatively major role in adhesion, motility, and biofilm formation, while TonB3 is more involved in the anti-phagocytosis of A. hydrophila. In each observed phenotype, no significant difference was found between the single- and double-deletion mutants, whereas the triple-deletion mutant exhibited the most serious defects, indicating that all three TonB systems of A. hydrophila coordinately complement one another. In conclusion, this study elucidates the importance of TonB in iron acquisition and virulence of A. hydrophila, which lays the foundation for future studies regarding the survival mechanisms of this bacterium in iron-restricted environments.