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Symbiotic interactions between rhizobia and legumes result in the formation of root nodules, which fix nitrogen that can be used for plant growth. Rhizobia usually invade legume roots through a plant-made tunnel-like structure called an infection thread (IT). RPG (Rhizobium-directed polar growth) encodes a coiled-coil protein that has been identified in Medicago truncatula as required for root nodule infection, but the function of RPG remains poorly understood. In this study, we identified and characterized RPG in Lotus japonicus and determined that it is required for IT formation. RPG was induced by Mesorhizobium loti or purified Nodulation factor and displayed an infection-specific expression pattern. Nodule inception (NIN) bound to the RPG promoter and induced its expression. We showed that RPG displayed punctate subcellular localization in L. japonicus root protoplasts and in root hairs infected by M. loti. The N-terminal predicted C2 lipid-binding domain of RPG was not required for this subcellular localization or for function. CERBERUS, a U-box E3 ligase which is also required for rhizobial infection, was found to be localized similarly in puncta. RPG co-localized and directly interacted with CERBERUS in the early endosome (TGN/EE) compartment and near the nuclei in root hairs after rhizobial inoculation. Our study sheds light on an RPG-CERBERUS protein complex that is involved in an exocytotic pathway mediating IT elongation. Author summary: In legume-rhizobium symbiotic interactions, growth of the plant-made infection thread (IT) through epidermal and cortical root cells is led by nuclear movement. RPG is a gene that is present in nitrogen-fixing root nodule (NFN) clades and is specifically required for IT formation. In this study, we found that RPG and CERBERUS co-localize and interact in root hairs close to the nucleus after rhizobial inoculation. Both are essential for normal IT growth, both co-localize in the TGN/EE compartment and are required for endomembrane dynamics during IT formation. Our study sheds light on how the RPG-CERBERUS complex promotes IT elongation. [ABSTRACT FROM AUTHOR]

The creation of microwells on an electrode surface has been used to improve the electrode performance. Herein, we report the fabrication of a microwell bipolar electrode array (MBEA) by selectively etching a fiber core and coating a thin gold layer on one pole of optical fiber bundle. The remote electrochemiluminescence (ECL) sensing platform is developed with the combination of the MBEA and ECL, such that light emission is generated at the distal face of the optical fiber bundle and detected at its proximal face. The resulting microwells in the MBEA can enhance the ECL generation, and produce a bell‐like ECL emission, for which higher light intensity is measured in the center of the fiber core than around its periphery. Then, it is revealed in theoretical simulations that the parabolic‐shaped bottom in the microwell induces the strong overlapped diffusion fields in its center and promotes the generation of ECL there. Finally, the application of MBEA is demonstrated in the detection of nicotinamide adenine dinucleotide (NADH). [ABSTRACT FROM AUTHOR]

Summary: CERBERUS (also known as LIN) and VAPYRIN (VPY) are essential for infection of legumes by rhizobia and arbuscular mycorrhizal fungi (AMF). Medicago truncatula LIN (MtLIN) was reported to interact with MtVPY, but the significance of this interaction is unclear and the function of VPY in Lotus japonicus has not been studied.We demonstrate that CERBERUS has auto‐ubiquitination activity in vitro and is localized within distinct motile puncta in L. japonicus root hairs and in Nicotiana benthamiana leaves. CERBERUS colocalized with the trans‐Golgi network/early endosome markers.In L. japonicus, two VPY orthologs (LjVPY1 and LjVPY2) were identified. CERBERUS interacted with and colocalized with both LjVPY1 and LjVPY2. Co‐expression of CERBERUS with LjVPY1 or LjVPY2 in N. benthamiana led to increased protein levels of LjVPY1 and LjVPY2, which accumulated as mobile punctate bodies in the cytoplasm. Conversely, LjVPY2 protein levels decreased in cerberus roots after rhizobial inoculation. Mutant analysis indicates that LjVPY1 and LjVPY2 are required for rhizobial infection and colonization by AMF.Our data suggest that CERBERUS stabilizes LjVPY1 and LjVPY2 within the trans‐Golgi network/early endosome, where they might function to regulate endocytic trafficking and/or the formation or recycling of signaling complexes during rhizobial and AMF symbiosis. [ABSTRACT FROM AUTHOR]

3,4-Dihydroxyphenylalanine (DOPA), an analogue of dopamine (DA), has been used to prepare fluorescent organic nanoparticles (FONs) through the electrochemical oxidation method. The as-prepared polyDOPA-FONs have good optical properties and diverse functional groups on the surfaces and can serve as fluorescent probes for different targets. Herein, we have fully exploited the sensing properties of the polyDOPA-FONs. Fe3+, Cu2+ and Hg2+ could induce significant fluorescence quenching of the polyDOPA-FONs in water, and selective fluorescence quenching in three buffer solutions. A turn-off sensor was further established in a buffer solution system to detect Fe3+, Cu2+ and Hg2+ using the same polyDOPA-FONs. Based on the sensitive and selective fluorescence quenching in a different buffer solution, this sensor could also be applied to analyze the three metal ions in water samples. Finally, the possibility for the fabrication of an "ON–OFF" sensor and the recycling of the polyDOPA-FONs was confirmed by reversibly switching the fluorescence in Fe3+/pyrophosphate ion (PPi), Cu2+/cysteine (Cys) and Hg2+/ascorbic acid (AA) couples. [ABSTRACT FROM AUTHOR]

Although the effect of bacterial infection on cirrhosis has been well-described, the effect of non-hepatotropic virus (NHV) infection is unknown. This study evaluated the genome fragments of circulating microorganisms using metagenomic next-generation sequencing (mNGS) in individuals with acute decompensation (AD) of cirrhosis, focusing on NHVs, and related the findings to clinical outcomes. Plasma mNGS was performed in 129 individuals with AD of cirrhosis in the study cohort. Ten healthy volunteers and 20, 39, and 81 individuals with stable cirrhosis, severe sepsis and hematological malignancies, respectively, were enrolled as controls. Validation assays for human cytomegalovirus (CMV) reactivation were performed in a validation cohort (n = 58) and exploratory treatment was instituted. In the study cohort, 188 microorganisms were detected in 74.4% (96/129) of patients, including viruses (58.0%), bacteria (34.1%), fungi (7.4%) and chlamydia (0.5%). A NHV signature was identified in individuals with AD, and CMV was the most frequent NHV, which correlated with the clinical effect of empirical antibiotic treatment, progression to acute-on-chronic liver failure, and 90-day mortality. The NHV signature in individuals with acute-on-chronic liver failure was similar to that in those with sepsis and hematological malignancies. CMV was detected in 24.1% (14/58) of patients in the validation cohort. Of the 14 cases with detectable CMV by mNGS, nine were further validated by real-time PCR or pp65 antigenemia testing. Three patients with CMV reactivation received ganciclovir therapy in an exploratory manner and experienced clinical resolutions. The results of this study suggest that NHVs may play a pathogenic role in complicating the course of AD. Further validation is needed to define whether this should be incorporated into the routine management of individuals with AD of cirrhosis. A non-hepatotropic virus (NHV) signature, which was similar to that in individuals with sepsis and hematological malignancies, was identified in individuals with acute decompensation of cirrhosis. The detected viral signature had clinical correlates, including clinical efficacy of empirical antibiotic treatment, progression to acute-on-chronic liver failure and short-term mortality. Cytomegalovirus reactivation, which is treatable, may adversely affect clinical outcomes in some individuals with decompensated cirrhosis. Routine screening for NHVs, especially cytomegalovirus, may be useful for the management of individuals with acute decompensation of cirrhosis. [Display omitted] • A non-hepatotropic viral signature was identified in individuals with AD of cirrhosis. • This viral signature correlated with clinical outcomes. • CMV reactivation might play a pathogenic role in AD and progression toward ACLF. • Further refinement and validation are needed to define the clinical relevance of our results. [ABSTRACT FROM AUTHOR]

Background: Early detection of hepatocellular carcinoma (HCC) among hepatitis B virus (HBV)-infected patients remains a challenge, especially in China. We sought to create an online calculator of serum biomarkers to detect HCC among patients with chronic hepatitis B (CHB)., Methods: Participants with HBV-HCC, CHB, HBV-related liver cirrhosis (HBV-LC), benign hepatic tumors, and healthy controls (HCs) were recruited at 11 Chinese hospitals. Potential serum HCC biomarkers, protein induced by vitamin K absence or antagonist-II (PIVKA-II), α-fetoprotein (AFP), lens culinaris agglutinin A-reactive fraction of AFP (AFP-L3) and α-l-fucosidase (AFU) were evaluated in the pilot cohort. The calculator was built in the training cohort via logistic regression model and validated in the validation cohort., Results: In the pilot study, PIVKA-II and AFP showed better diagnostic sensitivity and specificity compared with AFP-L3 and AFU and were chosen for further study. A combination of PIVKA-II and AFP demonstrated better diagnostic accuracy in differentiating patients with HBV-HCC from patients with CHB or HBV-LC than AFP or PIVKA-II alone [area under the curve (AUC), 0.922 (95% CI, 0.908-0.935), sensitivity 88.3% and specificity 85.1% for the training cohort; 0.902 (95% CI, 0.875-0.929), 87.8%, and 81.0%, respectively, for the validation cohort]. The nomogram including AFP, PIVKA-II, age, and sex performed well in predicting HBV-HCC with good calibration and discrimination [AUC, 0.941 (95% CI, 0.929-0.952)] and was validated in the validation cohort [AUC, 0.931 (95% CI, 0.909-0.953)]., Conclusions: Our results demonstrated that a web-based calculator including age, sex, AFP, and PIVKA-II accurately predicted the presence of HCC in patients with CHB., Clinicaltrialsgov Identifier: NCT03047603., (© 2019 American Association for Clinical Chemistry.)