CXCR3-CXCL11 Signaling Restricts Angiogenesis and Promotes Pericyte Recruitment.

BACKGROUND: Endothelial cell (EC)-pericyte interactions are known to remodel in response to hemodynamic forces; yet there is a lack of mechanistic understanding of the signaling pathways that underlie these events. Here, we have identified a novel signaling network regulated by blood flow in ECs-the chemokine receptor CXCR3 (CXC motif chemokine receptor 3) and one of its ligands, CXCL11 (CXC motif chemokine ligand 11)-that delimits EC angiogenic potential and promotes pericyte recruitment to ECs during development. METHODS: We investigated the role of CXCR3 on vascular development using both 2- and 3-dimensional in vitro assays, to study EC-pericyte interactions and EC behavioral responses to blood flow. Additionally, genetic mutants and pharmacological modulators were used in zebra fish in vivo to study the impacts of CXCR3 loss and gain of function on vascular development. RESULTS: In vitro modeling of EC-pericyte interactions demonstrates that suppression of EC-specific CXCR3 signaling leads to loss of pericyte association with EC tubes. In vivo, phenotypic defects are particularly noted in the cranial vasculature, where we see a loss of pericyte association with ECs and expansion of the vasculature in zebra fish treated with the Cxcr3 inhibitor AMG487 or in homozygous cxcr3.1/3.2/3.3 triple mutants. We also demonstrate that CXCR3-deficient ECs are more elongated, move more slowly, and have impaired EC-EC junctions compared with their control counterparts. CONCLUSIONS: Our results suggest that CXCR3 signaling in ECs helps promote vascular stabilization events during development by preventing EC overgrowth and promoting pericyte recruitment.

Thrombin-targeted screening of anticoagulant active components from Polygonum amplexicaule D. Don var. sinense Forb by affinity ultrafiltration coupled with UPLC-Q-TOF-MS.

INTRODUCTION: Polygonum amplexicaule D. Don var. sinense Forb (PAF), a medicinal plant, has the effect of promoting blood circulation and removing blood stasis. However, the active compounds and targets of its anticoagulant effect are still unclear. OBJECTIVES: This study aims to establish an effective reversely thrombin-targeted screening method for anticoagulant active components in PAF by affinity ultrafiltration (AUF) coupled with ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectroscopy (UPLC-Q-TOF-MS). METHODS: Different polar parts of PAF were screened for potential thrombin ligands by AUF-HPLC and identified by UPLC-Q-TOF-MS. After studying the affinity between ligands and thrombin by molecular docking, the antithrombotic activity of ligands was detected in vivo by zebrafish thrombus model, and in vitro by chromogenic substrate method. The mechanism of such ligands on thrombin was further studied by coagulation factor assay. RESULTS: Eleven potential thrombin ligands from PAF were screened by the AUF-UPLC-Q-TOF-MS method, and two compounds (butyl gallate and ß-sitosterol) with significant anticoagulant activity were discovered via in vitro and in vivo activity testing. CONCLUSION: A method system based on AUF-UPLC-Q-TOF-MS, molecular docking and in vivo and in vitro experiments also provided a powerful tool for further exploration of anticoagulant active components in PAF.

Vitamin B12 alleviates malathion-induced toxicity in zebra fish by regulating cytochrome P450 and PgP expressions.

The indiscriminate and rampant use of pesticides has raised serious concerns regarding their toxic impact on non-target organisms which underlines need for the development of an effective antidote. Metabolic activation of organophosphate pesticides by the phase I enzyme, cytochrome P450 plays a key role in influencing pesticide-toxicity. In this study, we have investigated the effect of environmentally relevant malathion concentration (100 µg/L) alone and in combination with vitamin B12 on the expression of genes related to xenobiotic metabolism such as CYP enzymes, PgP and the key oxidative stress responsive transcription factor, Nrf2 in zebra fish liver and brain. Expressions of Nrf2-trasncribed antioxidant genes and their activities were also measured. Administration of vitamin B12 successfully revived motor functions by modulation of AchE activity. Mechanistically, vitamin B12 was demonstrated to alleviate oxidative stress which was accompanied by decreased phase-I enzyme cyp3c1 and increased pgp expressions.

Toxicity of green synthesized TiO2 nanoparticles (TiO2 NPs) on zebra fish.

Nanoparticles (NPs) is usually fabricated by physical and chemical methods which, consequently, may have adverse effects for human and environment. Therefore, novel environmentally friendly synthesis methods for are essential and preferred. The purpose of this study was to synthesize TiO2 NPs using Echinophora cinerea extract and evaluate its toxicity on zebra fish. In the work, extraction phase was performed using a water as solvent. FTIR, XRD, SEM, and DLS analyzes were performed to determine the characteristics of synthesized TiO2 NPs. The effect of different parameters such as pH, extract concentration, TiO2 concentration, and temperature were investigated on TiO2 NP and optimized. Then, the acute toxicity of synthesized TiO2 NPs at different concentrations was investigated for 96 h on zebra fish. The bioassay data was analyzed via probit regression technique. Based on the obtained results, the optimal conditions for the synthesized TiO2 NPs were 9, 20 g/L, 0.4 g/L, and 25 °C for pH, extract concentration, TiO2 concentration and temperature, respectively. Both FTIR and XRD analysis confirmed the stability and structure of the synthesized NPs. According to SEM and DLS analysis, the synthesized NPs were spherical in shape and about 244.7 nm in diameter. Based on bioassay, LC50 for green synthesized TiO2 NPs with Echinophora cinerea extract at 48 h was 300 mg/L, which revealed a less hazardous material.

Ecotoxicological effects of conventional herbicides and a natural herbicide on freshwater fish (Danio rerio).

The contamination of aquatic environments has increased over time, affecting environmental integrity and human health. Herbicides represent a source of this contamination, and among the most commercialized are the triazines and glyphosate. In contrast, there are natural herbicides, which are less harmful to the environment. The aim of this study was to verify the ecotoxicological effects of the conventional herbicides (Atrazine and Glyphosate) and a natural herbicide on Zebrafish (Danio rerio). Fish were exposed for 72 h to different concentrations of conventional herbicides (1, 65, and 5,000 µg L-1) and the natural herbicide (0.62, 1.25, and 2.5 µg L-1) in aquaria (20 L). At end of the experiment, blood was collected from the fish, and slides were prepared to verify the frequency of nuclear abnormalities and micronuclei. A greater number of morphological nuclear alterations were recorded in the conventional herbicide treatments. In addition, significant differences were observed in the composition of abnormalities between treatments. Atrazine and Glyphosate can cause greater damage in D. rerio, demonstrating potential toxicity at all concentrations applied. The natural herbicide showed less mutagenic potential and was less harmful to fish. Thus, natural herbicides can be a better option for the preservation of the environment.

Neurotoxicity and physiological stress in brain of zebrafish chronically exposed to tributyltin.

Tributyltin (TBT), an organotin compound, is hazardous in aquatic ecosystems. However, the mechanisms underlying TBT-induced central nervous system (CNS) toxicity remain to be determined especially in freshwater aquatic vertebrates. The aim of present study was to investigate the effects of chronic exposure to TBT on brain functions in a freshwater teleost the adult wild-type zebrafish (Danio rerio). Fish were exposed to sublethal concentrations of TBT (10, 100 or 300 ng/L) for 6 weeks. The influence of long-term TBT exposure was assessed in the brain of zebrafish with antioxidant related indices including malondialdehyde (MDA) levels and total antioxidant capacity, neurological parameters such as activities of acetylcholinesterase, and monoamine oxidase as well as levels of nitric oxide, dopamine, 5-hydroxytryptamine. In addition indices related to sensitivity of toxic insult such as cytochrome P450 1 regulation and heat shock protein 70 were determined. The regulation of related genes involved in endoplasmic reticulum stress (ERS), apoptosis and Nrf2 pathway were measured. Adverse physiological and biochemical responses were significantly enhanced in a concentration-dependent manner reflecting neurotoxicity attributed to TBT exposure. Our findings provide further insight into TBT-induced toxicity in wild-type zebrafish. and enhance our understanding of the molecular mechanisms underlying TBT-initiated CNS effects.

Characterization and preliminary safety evaluation of nano-SiO2 isolated from instant coffee.

The physiological and toxicological evaluation of nano-silicon dioxide (nano-SiO2) particles in food is important for ensuring food safety. In this study, nano-SiO2 particles isolated from five brands of instant coffee, were structurally characterized using transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, and zeta potential analyses. Their toxicity was assessed by measuring cell viability, membrane integrity, and reactive oxygen species (ROS) levels in model gastrointestinal cells (GES-1 and Caco-2). Additionally, mortality, deformity rate, heart rate and death of whole zebra fish embryos were measured. The five types of nano-SiO2 samples comprised amorphous particles with a purity of approximately 99%, which met the food additive standard. Considering that the original particle size ranged from 10 to 50 nm, the samples were classified as nano-SiO2 food additives. Nano-SiO2 did not significantly impact the activity of GES-1 or Caco-2 cells, and no significant cell membrane damage was observed (Caco-2 cells exhibited mild micro damage); however, a slight increase in intracellular RPS levels was detected. Moreover, nano-SiO2 was found to cause head deformity, pericardial edema, yolk sac edema and tail bending. Collectively, the results show that nano-SiO2 time- and dose-dependently affects GES-1 and Caco-2 cell viability, as well as the mortality, heart rate, and abnormality rate of zebra fish embryos. Specifically, a high concentration (≥ 200 µg/mL) and long exposure time (≥ 48 h) of food additive nano-SiO2 affected GES-1, Caco-2 cells, and the gastrointestinal tract in zebra fish embryos.

The Temporal Mechanisms Guiding Interneuron Differentiation in the Spinal Cord.

Neurogenesis timing is an essential developmental mechanism for neuronal diversity and organization throughout the central nervous system. In the mouse spinal cord, growing evidence is beginning to reveal that neurogenesis timing acts in tandem with spatial molecular controls to diversify molecularly and functionally distinct post-mitotic interneuron subpopulations. Particularly, in some cases, this temporal ordering of interneuron differentiation has been shown to instruct specific sensorimotor circuit wirings. In zebrafish, in vivo preparations have revealed that sequential neurogenesis waves of interneurons and motor neurons form speed-dependent locomotor circuits throughout the spinal cord and brainstem. In the present review, we discuss temporal principals of interneuron diversity taken from both mouse and zebrafish systems highlighting how each can lend illuminating insights to the other. Moving forward, it is important to combine the collective knowledge from different systems to eventually understand how temporally regulated subpopulation function differentially across speed- and/or state-dependent sensorimotor movement tasks.

Synthesis, in vitro, and in vivo (Zebra fish) antitubercular activity of 7,8-dihydroquinolin-5(6H)-ylidenehydrazinecarbothioamides.

We, herein, describe the synthesis of a series of novel aryl tethered 7,8-dihydroquinolin-5(6H)-ylidenehydrazinecarbothioamides 4a-v, which showed in vitro and in vivo antimycobacterial activity against Mycobacterium tuberculosis (Mtb) H37Rv. The intermediates dihydro-6H-quinolin-5-ones 3a-v were synthesized from ß-enaminones, reacting with cyclochexane-1,3-dione/5,5-dimethylcyclohexane-1,3-dione and ammonium acetate using a modified Bohlmann-Rahtz reaction conditions. They were further reacted with thiosemicarbazide to give the respective hydrazine carbothioamides 4a-v. All the new analogues 4a-v, were characterized by their NMR and mass spectral data analysis. Among the twenty-two compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC27294), two compounds, 4e and 4j, exhibited the highest inhibition with an MIC of 0.39 µg/mL. Compounds 4a, 4g, and 4k were found to inhibit Mtb at an MIC of 0.78 µg/mL. Hydrazinecarbothioamides 4a-k, exhibited enhanced activity than dihydroquinolinones 3a-k. The observed increase in potency provides a clear evidence that hydrazinecarbothioamide is a potential pharmacophore, collectively imparting synergistic effect in enhancing antitubercular activity of the dihydroquinolinone core. The in vivo (Zebra fish) antimycobacterial screening of the in vitro active molecules led to the identification of a hit compound, 4j, with significant activity in the Mtb nutrient starvation model (2.2-fold reduction). Docking studies of 4j showed a hydrogen bond with the P156 residue of the protein.

Impact of nanomaterials on ecosystems: Mechanistic aspects in vivo.

Nanotechnologies are becoming increasingly popular in modern era of human development in every aspect of life. Their impact on our ecosystem in air, soil, and water is largely unknown because of the limited amount of information available, and hence, they require considerable attention. This account highlights the important routes of nanomaterials toxicity in air, soil, and water, their possible impact on the ecosystem and aquatic life. The mechanistic aspects have been focused on the size, shape, and surface modifications of nanomaterials. The preventive measures and future directions along with appropriate designs and implementation of nanotechnologies have been proposed so as to minimize the interactions of nanomaterials with terrestrial flora and aquatic life. Specifically, the focus largely remains on the toxicity of metallic nanoparticles such as gold (Au) and silver (Ag) because of their applications in diverse fields. The account lists some prominent mechanistic routes of nanotoxicity along with in vivo experimental results based on the fundamental understanding that how nanometallic surfaces interact with plant as well as animal biological systems. The appropriate modifications of the nanometallic surfaces with biocompatible molecules are considered to be the most effective preventive measures to reduce the nanotoxicity.

Alternatives to Animal Use in Risk Assessment of Mixtures.

Risk assessment of chemical mixtures has emerged as a focus of research efforts, but traditional toxicology testing in mammals is costly, time-consuming, and subject to ethical scrutiny in the context of recent trends to reduce reliance on animal testing. In this review, which is a summary of presentations given at a workshop in Havana, Cuba, in April 2019, we survey the utility of zebra fish as an alternative laboratory model in whole-mixture and component-based testing, as well as in vitro modeling in 3-dimensional organotypic cultures from primary human cells cultured at the air-liquid interface and organ-on-a-chip platforms. Finally, we discuss the complexities of assessing the dynamics and delivery of multispecies liquid aerosol mixtures along the human respiratory tract, with examples of alternative and computational approaches to aerosol dosimetry. The workshop contributed to the professional development of Cuban toxicologists, an underserved segment of the global scientific community, delivering a set of tools and recommendations that could potentially provide cost-effective solutions for scientists with limited research resources.

An overview of organic matters in municipal wastewater: Removal via self-assembly flocculating mechanism and the molecular level characterization.

On considering the critical issues in attaining stringent water quality standards and not creating any environmental impacts, we focused for the first time the economically feasible, emerging technology known as Self-assembly flocculating (Saf process). In which, the study investigated the applicability of bioflocculant (a biopolymer-self-assembly in nature) act as a surrogates on relying the removal of broad spectrum of substances under optimized conditions (Dosage: 90 mg/L; pH: 7; CaCl2). On using different techniques, the results have proved in removing the organic matter such as pharmaceuticals (Gentamycin, Cholecalciferol, Fluvoxamine, 3-OH Desogestrel, and Pheniramine), endocrine disturbing compounds [Phthalic acid, Benzene, 1, 2, 4 -Trimethoxy-5-(1-Propenyl)-, Benzene, 1, 2-Dimethoxy-4-(2-Propenyl)-, 1, 2-Benzenedicarboxylic Acid, 3-Cyclohexen-1-ol], fluorescent components (Polysaccharide like material), and others. The toxicological assessment of self-assembly bioflocculant implemented on zebra fish were statistically correlated [r = 0.95, p < 0.01 and 0.05 for P1WW; r = 0.91, p < 0.01 and 0.05 for P2WW] and [r = 0.7 5, p < 0.05 for P1WT; r = 0.095, p < 0.01 and 0.05 for P2WT]. This integrated approach supplemented further information of zeta potential (-16 mV in P1WW and -14.6 mV in P2WW decreased to -1.05 mV and -1.56 mV) with particle size distribution to explain via Saf process. In this research, the new insight has established non-toxic, self-assembly, biodegradable, bioflocculant for effective bioremediation.

Functional Comparison of Human and Zebra Fish FKBP52 Confirms the Importance of the Proline-Rich Loop for Regulation of Steroid Hormone Receptor Activity.

Previous studies demonstrated that the 52-kDa FK506-binding protein (FKBP52) proline-rich loop is functionally relevant in the regulation of steroid hormone receptor activity. While zebra fish (Danio rerio; Dr) FKBP52 contains all of the analogous domains and residues previously identified as critical for FKBP52 potentiation of receptor activity, it fails to potentiate activity. Thus, we used a cross-species comparative approach to assess the residues that are functionally critical for FKBP52 function. Random selection of gain-of-function DrFKBP52 mutants in Saccharomyces cerevisiae identified two critical residues, alanine 111 (A111) and threonine 157 (T157), for activation of receptor potentiation by DrFKBP52. In silico homology modeling suggests that alanine to valine substitution at position 111 in DrFKBP52 induces an open conformation of the proline-rich loop surface similar to that observed on human FKBP52, which may allow for sufficient surface area and increased hydrophobicity for interactions within the receptor-chaperone complex. A second mutation in the FKBP12-like domain 2 (FK2), threonine 157 to arginine (T157R), also enhanced potentiation, and the DrFKBP52-A111V/T157R double mutant potentiated receptor activity similar to human FKBP52. Collectively, these results confirm the functional importance of the FKBP52 proline-rich loop, suggest that an open conformation on the proline-rich loop surface is a predictor of activity, and highlight the importance of an additional residue within the FK2 domain.

Lead identification and optimization of bacterial glutamate racemase inhibitors.

Mycobacterium tuberculosis glutamate racemase is an essential enzyme involved in peptidoglycan synthesis and conserved in most bacteria. Small molecule inhibitors were reported on other bacterial species whereas in M. tuberculosis it wasn't explored much. In this study we have screened in house compound library using fluorescence thermal shift assay and enzyme inhibition assay, form this (1-(3-(benzo[d]thiazol-2-yl)phenyl)-3-(p-tolyl)thiourea) was identified as lead compound with IC50 19.47 ±â€¯0.81 µM. Further lead optimization by synthesis resulted in twenty-three compounds, of which Compound 25 has shown more efficacy compared to lead 1 showing non-competitive mode of inhibition with IC50 1.32 ±â€¯0.43 µM. It also showed significant activity (represented in log reduction) in nutrient starved dormant M. tuberculosis model (2.1), M. tuberculosis biofilm assay (2.0) and in vivo M. marinum infected zebrafish model (3.5).

Native hypersaline sulphate reducing bacteria contributes to iron nanoparticle formation in saltpan sediment: A concern for aquaculture.

A hypersaline dissimilatory sulphate reducing bacterium, strain LS4, isolated from the sediments of Ribander saltpan, Goa, India was found to produce (Fe2O3) maghemite nanoparticles. The presence of maghemite nanoparticles was also detected in the same sediment. Strain LS4 was isolated anaerobically on modified Hatchikian's media at 300 psu, growing optimally at 30 °C, 150 psu salinity and pH 7.8. Based on biochemical characteristics and 16S rRNA sequence analysis, the strain LS4 belongs to genus Desulfovibrio. This isolate synthesized iron oxide nanoparticles in vitro when challenged with FeCl3 & FeSO4 in the growth medium. The biological nanoparticles were characterized to be Fe2O3 nanoparticle of 19 nm size by X-ray diffraction, transmission electron microscopy, fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive x-ray spectroscopy. Maghemite nanoparticles (5.63 mg g-1) were isolated from the saltpan sediment by magnetic separation which showed similar characteristic features to the Fe2O3 nanoparticle produced by strain LS4 with an average size of 18 nm. Traditionally Goan saltpans were used for aquaculture during the non-salt making season, thus effects of these nanoparticles on Zebra fish embryo development were checked, which resulted in developmental abnormalities and DNA damage in a dose dependent manner. With the increasing nanoparticle concentration (0.1 mg.L-1 to100 mg.L-1), the mortality rate increased with a decrease in the hatching rate (93.05 ± 2.4 to 25 ± 4.16%) and heart rate (150-120 beats per minute). The nanoparticle exposed embryos developed malformed larvae with a characteristic of pericardial edema, curved body, curved notochord, curved tail and curved tail tip. These results suggest that strain LS4 might be playing a role as a contributor in the formation of iron oxide nanoparticle in the Ribander saltpan sediment, however; its high concentration will have a negative impact on aquaculture in these saltpans.

Preparation of biologically active monomeric recombinant zebrafish (Danio rerio) and rainbow trout (Oncorhynchus mykiss) recombinant growth hormones.

Fish growth hormones (GHs) play an important role in regulating growth, metabolism, reproduction, osmoregulation, and immunity and have thus garnered attention for their application in aquaculture. Zebrafish GH (zGH) cDNA or rainbow trout GH (rtGH) cDNA was cloned into the pMon3401 vector, expressed in MON105-competent Escherichia coli and purified to homogeneity. Their biological activity was evidenced by their ability to interact with ovine GH receptor extracellular domain and stimulate GH receptor-mediated proliferation in FDC-P1-3B9 cells stably transfected with rabbit GH receptor. The relative affinity of zGH and rtGH, estimated by IC50, was about 38-fold and 512-fold lower, respectively, than ovine GH. This is likely the reason for the low biological activity in cells with rabbit GH receptor, ~ 36-fold lower for zGH and ~ 107-fold lower for rtGH than for human GH. This was not due to improper refolding, as evidenced by circular dichroism analysis. Predicting the activity of fish GHs is problematic as there is no one single optimal in vitro bioassay; heterologous assays may be ambiguous, and only homologous assays are suitable for measuring activity.

Tetracycline-loaded calcium phosphate nanoparticle (Tet-CPNP): Rejuvenation of an obsolete antibiotic to further action.

BACKGROUND: Increasing resistance in bacteria towards antibiotics has made it imperative to research on their revitalization to combat infectious diseases. This study dealt with synthesis of a nano-form of the antibiotic tetracycline, its characterization and potency of killing different multi-drug resistant diarrhea-causing bacteria. METHODS: Nano-formulation was done by loading tetracycline within biocompatible calcium phosphate nanoparticle. The synthesized tetracycline-loaded calcium phosphate nanoparticle (Tet-CPNP) was characterized by the techniques like TEM, DLS, EDS, FTIR, spectrofluorimetry and dialysis. Bactericidal activity of nano-particulate tetracycline was investigated by agar plating, spectrophotometry, phase contrast-fluorescence-atomic force microscopy and flow cytometry techniques. RESULTS: The Tet-CPNPs were 8±5nm in size and nearly spherical in shape, efficiency of tetracycline loading in CPNP was about 20% and the release of antibiotic from Tet-CPNPs was sustainable during 7days. Minimum inhibitory concentration (MIC) of Tet-CPNP on multiple antibiotic (including tetracycline) resistant bacteria like Escherichia coli, Salmonella kentuckey and Shigella flexneri was in the range of 20-40µg/ml, whereas MIC of free tetracycline was in the range of 150-180µg/ml. NP-mediated cell filamentation and cell membrane disintegration caused cell killing. Moreover, death of Shigella-infected Zebra fish larvae was stalled by Tet-CPNP treatment. CPNP itself had no toxic effect on bacteria as well as on Zebra fish. CONCLUSION: Our nano-formulation of tetracycline might reclaim a nearly obsolete antibiotic to further potential function. GENERAL SIGNIFICANCE: Such a study on revival of an old, cheap, broad-spectrum antibiotic to further action is highly beneficial to developing countries with limited health care budgets.

Coinfection outcome in an opportunistic pathogen depends on the inter-strain interactions.

BACKGROUND: In nature, organisms are commonly coinfected by two or more parasite strains, which has been shown to influence disease virulence. Yet, the effects of coinfections of environmental opportunistic pathogens on disease outcome are still poorly known, although as host-generalists they are highly likely to participate in coinfections. We asked whether coinfection with conspecific opportunistic strains leads to changes in virulence, and if these changes are associated with bacterial growth or interference competition. We infected zebra fish (Danio rerio) with three geographically and/or temporally distant environmental opportunist Flavobacterium columnare strains in single and in coinfection. Growth of the strains was studied in single and in co-cultures in liquid medium, and interference competition (growth-inhibiting ability) on agar. RESULTS: The individual strains differed in their virulence, growth and ability for interference competition. Number of coinfecting strains significantly influenced the virulence of infection, with three-strain coinfection differing from the two-strain and single infections. Differences in virulence seemed to associate with the identity of the coinfecting bacterial strains, and their pairwise interactions. This indicates that benefits of competitive ability (production of growth-inhibiting compounds) for virulence are highest when multiple strains co-occur, whereas the high virulence in coinfection may be independent from in vitro bacterial growth. CONCLUSIONS: Intraspecific competition can lead to plastic increase in virulence, likely caused by faster utilization of host resources stimulated by the competitive interactions between the strains. However, disease outcome depends both on the characteristics of individual strains and their interactions. Our results highlight the importance of strain interactions in disease dynamics in environments where various pathogen genotypes co-occur.

Manganese and cobalt activate zebrafish ovarian cancer G-protein-coupled receptor 1 but not GPR4.

Mammalian ovarian G-protein-coupled receptor 1 (OGR1) is activated by some metals in addition to extracellular protons and coupling to multiple intracellular signaling pathways. In the present study, we examined whether zebrafish OGR1, zebrafish GPR4, and human GPR4 (zOGR1, zGPR4, and hGPR4, respectively) could sense the metals and activate the intracellular signaling pathways. On one hand, we found that only manganese and cobalt of the tested metals stimulated SRE-promoter activities in zOGR1-overexpressed HEK293T cells. On the other hand, none of the metals tested stimulated the promoter activities in zGPR4- and hGPR4-overexpressed cells. The OGR1 mutant (H4F), which is lost to activation by extracellular protons, did not stimulate metal-induced SRE-promoter activities. These results suggest that zOGR1, but not GPR4, is also a metal-sensing G-protein-coupled receptor in addition to a proton-sensing G-protein-coupled receptor, although not all metals that activate hOGR1 activated zOGR1.

Is A/A/O process effective in toxicity removal? Case study with coking wastewater.

The anaerobic-anoxic-oxic (A/A/O) process is the commonly used biological wastewater treatment process, especially for the coking wastewater. However, limit is known about its ability in bio-toxicity removal from wastewater. In this study, we evaluated the performance of A/A/O process in bio-toxicity removal from the coking wastewater, using two test species (i.e. crustacean (Daphnia magna) and zebra fish (Danio rerio)) in respect of acute toxicity, oxidative damage and genotoxicity. Our results showed that the acute toxicity of raw influent was reduced gradually along with A/A/O process and the effluent presented no acute toxicity to Daphnia magna (D. magna) and zebra fish. The reactive oxygen species (ROS) level in D. magna and zebra fish was promoted by the effluent from each tank of A/A/O process, showing that coking wastewater induced oxidative damage. Herein, the oxidative damage to D. magna was mitigated in the oxic tank, while the toxicity to zebra fish was reduced in the anoxic tank. The comet assays showed that genotoxicity to zebra fish was removed stepwise by A/A/O process, although the final effluent still presented genotoxicity to zebra fish. Our results indicated that the A/A/O process was efficient in acute toxicity removal, but not so effective in the removal of other toxicity (e.g. oxidative damage and genotoxicity). Considering the potential risks of wastewater discharge, further advanced toxicity mitigation technology should be applied in the conventional biological treatment process, and the toxicity index should be introduced in the regulation system of wastewater discharge.