bGram-negative bacteria use N-acyl homoserine lactones (AHLs) as quorum sensing (QS) signaling molecules for interspecies communication, and AHL-dependent QS is related with virulence factor production in many bacterial pathogens. Quorum quenching, the enzymatic degradation of the signaling molecule, would attenuate virulence rather than kill the pathogens, and thereby reduce the potential for evolution of drug resistance. In a previous study, we showed that Muricauda olearia Th120, belonging to the class Flavobacteriia, has strong AHL degradative activity. In this study, an AHL lactonase (designated MomL), which could degrade both short-and long-chain AHLs with or without a substitution of oxo-group at the C-3 position, was identified from Th120. Liquid chromatography-mass spectrometry analysis demonstrated that MomL functions as an AHL lactonase catalyzing AHL degradation through lactone hydrolysis. MomL is an AHL lactonase belonging to the metallo-␤-lactamase superfamily that harbors an N-terminal signal peptide. The overall catalytic efficiency of MomL for C 6 -HSL is ϳ2.9 ؋ 10 5 s ؊1 M ؊1 . Metal analysis and site-directed mutagenesis showed that, compared to AiiA, MomL has a different metal-binding capability and requires the histidine and aspartic acid residues for activity, while it shares the "HXHXDH" motif with other AHL lactonases belonging to the metallo-␤-lactamase superfamily. This suggests that MomL is a representative of a novel type of secretory AHL lactonase. Furthermore, MomL significantly attenuated the virulence of Pseudomonas aeruginosa in a Caenorhabditis elegans infection model, which suggests that MomL has the potential to be used as a therapeutic agent. N-Acyl homoserine lactones (AHLs) are quorum-sensing (QS) signaling molecules that are used by many Gram-negative bacteria to communicate within species, to regulate gene expression and to synchronize social behaviors, such as biofilm formation, bioluminescence, and secretion of virulence factors (1, 2). An AHL molecule typically consists of a homoserine lactone and an acyl chain with an even number of carbons, with an occasional modification (hydroxy or olefinic double bond) at the C-3 position (1). It has been well established that AHL-dependent QS regulates virulence factor production in many bacterial pathogens, such as Pseudomonas aeruginosa, Erwinia carotovora, Vibrio spp., and Burkholderia spp. (1). Interference with QS has been recognized as a promising antivirulence therapy. Disturbing the QS systems in these pathogens would attenuate virulence rather than kill the bacteria and thereby weaken the selective pressure imposed on the pathogens and reduce the potential for evolution of drug resistance (3). QS inhibitors (QSIs; small molecules) and quorum-quenching (QQ) enzymes can both be used to interfere with QS. QSIs generally act to inactivate autoinducer synthases or receptors through competitive binding, whereas QQ enzymes switch off signal transmission through degradation of the signaling molecules. It has been demonstrated th...

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a lncRNA playing oncogenic role in several cancers, including cervical cancer. However, its role in radiosensitivity of cervical cancer is not yet well understood. This study explored the role of MALAT1 in radiosensitivity of high-risk human papillomavirus (HR-HPV)-positive cervical cancer and whether there is a ceRNA mechanism which participated in its regulation over radiosensitivity. Based on tissue samples from 50 cervical cancer cases and 25 healthy controls, we found MALAT1 expression was significantly higher in radioresistant than in radiosensitive cancer cases. In addition, MALAT1 and miR-145 expression inversely changed in response to irradiation in HR-HPV+ cervical cancer cells. By using clonogenic assay and flow cytometry analysis of cell cycle distribution and apoptosis, we found CaSki and Hela cells with knockdown of MALAT1 had significantly lower colony formation, higher ratio of G2/M phase block and higher ratio of cell apoptosis. By performing RNA-binding protein immunoprecipitation (RIP) assay and RNA pull-down assay, we confirmed that miR-145 and MALAT1 were in the same Ago2 complex and there was a reciprocal repression between them. Then, we explored the function of MALAT1-miR-145 in radiosensitivity of cervical cancers cells and demonstrated that si-MALAT1 and miR-145 had some level of synergic effect in reducing cancer cell colony formation, cell cycle regulation, and inducing apoptosis. These findings provide an important clue about microRNA-lncRNA interaction in the mechanism of radioresistance of cervical cancer.

Circulating levels of exosomal microRNAs miR-210 and miR-1233 have potential as biomarkers for diagnostic and monitoring purposes in renal cancer in the future. These molecules can be measured in serum in so-called liquid biopsy.

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Quorum sensing (QS) promotes in situ extracellular enzyme (EE) activity via the exogenous signal N-acylhomoserine lactone (AHL), which facilitates marine particle degradation, but the species that engage in this regulatory mechanism remain unclear. Here, we obtained AHL-producing and AHL-degrading strains from marine particles. The strain Ruegeria mobilis Rm01 of the Roseobacter group (RBG), which was capable of both AHL producing and degrading, was chosen to represent these strains. We demonstrated that Rm01 possessed a complex QS network comprising AHL-based QS and quorum quenching (QQ) systems and autoinducer-2 (AI-2) perception system. Rm01 was able to respond to multiple exogenous QS signals through the QS network. By applying self-generated AHLs and non-self-generated AHLs and AI-2 QS signal molecules, we modulated biofilm formation and lipase production in Rm01, which reflected the coordination of bacterial metabolism with that of other species via eavesdropping on exogenous QS signals. These results suggest that R. mobilis might be one of the participators that could regulate EE activities by responding to QS signals in marine particles.

Aims:  To isolate a bacterium that produces high yield of melanin and to examine the effect of this bacterial pigment on the efficacy of a bioinsecticide. Methods and Results:  A novel melanin‐producing bacterium, designated as strain WS, was isolated from the East Lake, Wuhan, China. Taxonomic studies of this strain indicate that it belongs to Aeromonas media. Physicochemical analysis of the pigment produced by strain WS (melanin WS) suggests that it is the authentic 3,4‐dihydroxyphenylalanine (DOPA)‐melanin. This melanin and that produced by Pseudomonas maltophilia P28 (melanin P28) share many biophysical properties, but the yield of the melanin WS is significantly higher than that of the melanin P28. In addition, the melanin WS appears to be more effective in the protection of a bioinsecticide against ultraviolet (UV) or solar radiation. At the concentration of 10 ppm, the melanin P28 exhibited no photoprotective effect on the bioinsecticide against UV radiation; in contrast, 5 ppm of melanin WS displayed an obvious protective effect. Similarly, the melanin WS displayed more protective effect on the bioinsecticide against solar radiation than the melanin P28 did over a 4‐day period, with the effect being more dramatic for the last 2 days. Conclusions:  We have isolated a novel bacterial strain of A. media that produces high levels of melanin. The melanin produced by this strain offers effective photoprotection of a commercial bioinsecticide BTI against UV and solar radiation. Significance and Impact of the Study:  Our study suggests that the melanin produced by our newly isolated A. media strain has the potential to be used as a general photoprotective agent for bioinsecticides.

Extracellular vesicles (EVs) are small membranous vesicles that contain an abundant cargo of different RNA species with specialized functions and clinical implications. Here, we introduce an updated online database (http://www.exoRBase.org), exoRBase 2.0, which is a repository of EV long RNAs (termed exLRs) derived from RNA-seq data analyses of diverse human body fluids. In exoRBase 2.0, the number of exLRs has increased to 19 643 messenger RNAs (mRNAs), 15 645 long non-coding RNAs (lncRNAs) and 79 084 circular RNAs (circRNAs) obtained from ∼1000 human blood, urine, cerebrospinal fluid (CSF) and bile samples. Importantly, exoRBase 2.0 not only integrates and compares exLR expression profiles but also visualizes the pathway-level functional changes and the heterogeneity of origins of circulating EVs in the context of different physiological and pathological conditions. Our database provides an attractive platform for the identification of novel exLR signatures from human biofluids that will aid in the discovery of new circulating biomarkers to improve disease diagnosis and therapy.

Evolutionary developmental biology, or Evo-Devo for short, has become an established field that, broadly speaking, seeks to understand how changes in development drive major transitions and innovation in organismal evolution. It does so via integrating the principles and methods of many subdisciplines of biology. Although we have gained unprecedented knowledge from the studies on model organisms in the past decades, many fundamental and crucially essential processes remain a mystery. Considering the tremendous biodiversity of our planet, the current model organisms seem insufficient for us to understand the evolutionary and physiological processes of life and its adaptation to exterior environments. The currently increasing genomic data and the recently available gene-editing tools make it possible to extend our studies to non-model organisms. In this review, we review the recent work on the regulatory signaling of developmental and regeneration processes, environmental adaptation, and evolutionary mechanisms using both the existing model animals such as zebrafish and Drosophila, and the emerging nonstandard model organisms including amphioxus, ascidian, ciliates, single-celled phytoplankton, and marine nematode. In addition, the challenging questions and new directions in these systems are outlined as well.