Europium Ion-Based Magnetic-Trapping and Fluorescence-Sensing Method for Detection of Pathogenic Bacteria.

Europium ions (Eu3+) have been utilized as a fluorescence-sensing probe for a variety of analytes, including tetracycline (TC). When Eu3+ is chelated with TC, its fluorescence can be greatly enhanced. Moreover, Eu3+ possesses 6 unpaired electrons in its f orbital, which makes it paramagnetic. Being a hard acid, Eu3+ can chelate with hard bases, such as oxygen-containing functional groups (e.g., phosphates and carboxylates), present on the cell surface of pathogenic bacteria. Due to these properties, in this study, Eu3+ was explored as a magnetic-trapping and sensing probe against pathogenic bacteria present in complex samples. Eu3+ was used as a magnetic probe to trap bacteria such as Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Acinetobacter baumannii, Bacillus cereus, and Pseudomonas aeruginosa. The addition of TC facilitated the easy detection of magnetic Eu3+-bacterium conjugates through fluorescence spectroscopy, with a detection limit of approximately ∼104 CFU mL-1. Additionally, matrix-assisted laser desorption/ionization mass spectrometry was employed to differentiate bacteria tapped by our magnetic probes.

DDX3 suppresses hepatocellular carcinoma progression through modulating the secretion and composition of exosome.

Due to the lack of predictive biomarkers and the lack of conspicuous symptoms at the early stage, hepatocellular carcinoma (HCC) remains difficult to diagnose and treat effectively. During cancer development, exosomes secreted from tumor cells carry functional molecules to surrounding recipient cells, thereby participating in the regulation of cancer progression. DDX3, a DEAD-box RNA helicase, performs many important functions in several cellular processes and is therefore implicated as a tumor suppressor in HCC. However, whether DDX3 affects the secretion and cargo sorting of HCC exosomes remains obscure. In this study, our results revealed that reduced DDX3 expression in HCC cells promoted the release of exosomes and enhanced the expression of several exosome biogenesis-associated proteins, such as exosome markers (e.g., TSG101, Alix, and CD63) and Rab proteins (e.g., Rab5, Rab11, and Rab35). By double knockdown of the expression of DDX3 and these exosome biogenesis-related factors, we confirmed that DDX3 participated in the regulation of exosome secretion by modulating the expression of these cellular factors in HCC cells. In addition, exosomes derived from DDX3-knockdown HCC cells enhanced cancer stem cell properties, including self-renewal capability, migration, and drug resistance, in recipient HCC cells. Moreover, up-regulation of the exosome markers TSG101, Alix, and CD63 as well as down-regulation of tumor-suppressive miR-200b and miR-200c were observed in exosomes derived from DDX3-knockdown HCC cells, which may account for the enhanced hepatic cancer stemness of the recipient cells treated with DDX3-knockdown HCC cell-derived exosomes. Taken together, our findings provide a new molecular mechanism supporting the tumor-suppressor role of DDX3 in HCC, which may contribute to the development of new therapeutic strategies against HCC.

Sumoylation participates in the regulation of YB-1-mediated mismatch repair deficiency and alkylator tolerance.

Numerous reports indicate that enhanced expression of Y-box binding protein-1 (YB-1) in tumor cells is strongly associated with tumorigenesis, aggressiveness, drug resistance, as well as poor prognosis in several types of cancers, and YB-1 is considered to be an oncogene. The molecular mechanism contributing to the regulation of the biological activities of YB-1 remains obscure. Sumoylation, a post-translational modification involving the covalent conjugation of small ubiquitin-like modifier (SUMO) proteins to a target protein, plays key roles in the modulation of protein functions. In this study, our results revealed that YB-1 is sumoylated and that Lys26 is a critical residue for YB-1 sumoylation. Moreover, YB-1 was found to directly interact with SUMO proteins, and disruption of the SUMO-interacting motif (SIM) of YB-1 not only interfered with this interaction but also diminished YB-1 sumoylation. The subcellular localization, protein stability, and transcriptional regulatory activity of YB-1 were not significantly affected by sumoylation. However, decreased sumoylation disrupted the interaction between YB-1 and PCNA as well as YB-1-mediated inhibition of the MutSα/PCNA interaction and MutSα mismatch binding activity, indicating a functional role of YB-1 sumoylation in inducing DNA mismatch repair (MMR) deficiency and spontaneous mutations. The MMR machinery also recognizes alkylator-modified DNA adducts to signal for cell death. We further demonstrated that YB-1 sumoylation is crucial for the inhibition of SN1-type alkylator MNNG-induced cytotoxicity, G2/M-phase arrest, apoptosis, and the MMR-dependent DNA damage response. Collectively, these results provide molecular explanations for the impact of YB-1 sumoylation on MMR deficiency and alkylator tolerance, which may provide insight for designing therapeutic strategies for malignancies and alkylator-resistant cancers associated with YB-1 overexpression.

Proteomic analyses bring new insights into the effect of a dark stress on lipid biosynthesis in Phaeodactylum tricornutum.

Microalgae biosynthesize high amount of lipids and show high potential for renewable biodiesel production. However, the production cost of microalgae-derived biodiesel hampers large-scale biodiesel commercialization and new strategies for increasing lipid production efficiency from algae are urgently needed. Here we submitted the marine algae Phaeodactylum tricornutum to a 4-day dark stress, a condition increasing by 2.3-fold the total lipid cell quotas, and studied the cellular mechanisms leading to lipid accumulation using a combination of physiological, proteomic (iTRAQ) and genomic (qRT-PCR) approaches. Our results show that the expression of proteins in the biochemical pathways of glycolysis and the synthesis of fatty acids were induced in the dark, potentially using excess carbon and nitrogen produced from protein breakdown. Treatment of algae in the dark, which increased algal lipid cell quotas at low cost, combined with optimal growth treatment could help optimizing biodiesel production.

Effects of atrazine on photosynthesis and defense response and the underlying mechanisms in Phaeodactylum tricornutum.

Atrazine (ATZ) is a commonly used herbicide that has recently come under scrutiny due to potential environmental toxicity and contamination. In this study, we found that the administration of ATZ indeed leads to reduction of photosynthesis and oxidative stress in Phaeodactylum tricornutum at the treated doses higher than 100 µg L(-1) after 48 h. We further explored the effect of ATZ on photosystem II (PSII) and gene expression of electron transport chain. Collectively, our results may suggest that ATZ entered the chloroplasts in alga depending on ATZ's liposolubility and directly attacked on the electron transport chain, especially PSII, contributing to reactive oxygen species (ROS) burst. The increasing ROS could act as signals to induce or disturb the expression of photosynthesis-related genes, resulting in the imbalance of antioxidation and pro-oxidation in the alga.

Climate change and food security in East Asia.

Climate change causes serious food security risk for East Asian countries. The United Nations Framework Convention on Climate Change (UNFCCC) has recognized that the climate change will impact agriculture and all nations should prepare adaptations to the impacts on food security. This article reviews the context of adaptation rules and current policy development in East Asian region. The UNFCCC and Kyoto Protocol have established specific rules for countries to develop national or regional adaptation policies and measurements. The current development of the ASEAN Strategic Plan on food security is inspiring, but the commitments to implementation by its members remain an issue of concern. We suggest that the UNFCCC enhances co-operation with the Food and Agriculture Organization (FAO) and other international organizations to further develop methodologies and technologies for all parties. Our findings suggest that agriculture is one of the most vulnerable sectors in terms of risks associated with climate change and distinct programmatic initiatives are necessary. It's imperative to promote co-operation among multilateral organizations, including the UNFCCC, FAO, World Health Organization, and others.

The nature of international health security.

Health issues occasionally intersect security issues. Health security has been viewed as an essential part of human security. Policymakers and health professionals, however, do not share a common definition of health security. This article aims to characterize the notions of health security in order to clarify what constitutes the nexus of health and security. The concept of health security has evolved over time so that it encompasses many entities. Analyzing the health reports of four multilateral organizations (the United Nations, World Health Organization, Asia-Pacific Economic Cooperation, and the European Union) produced eight categories of most significant relevance to contemporary health security, allowing comparison of the definitions. The four categories are: emerging diseases; global infectious disease; deliberate release of chemical and biological materials; violence, conflict, and humanitarian emergencies. Two other categories of common concern are natural disasters and environmental change, as well as chemical and radioactive accidents. The final two categories, food insecurity and poverty, are discussed less frequently. Nevertheless, food security is emerging as an increasingly important issue in public health. Health security is the first line of defence against health emergencies. As globalization brings more complexities, dealing with the increased scale and extent of health security will require greater international effort and political support.