The distribution of and biodegradation impact on spilled oil in sediments from Dalian Bay, NE China

Three cores collected in the area of 16th July 2010 oil spill by box crab in May 2013 and July 2014 at the Dalian Bay have been geochemically characterized to investigate the fate of chemical components in sediments. The total organic carbon, extractable organic matter contents and biomarker compositions have been applied for the differentiation of alien organic matters from in situ ones and evaluation of the biodegradation impact. Multivariate statistical analysis suggests four groups of sediments. Except a few samples at deepest part of BQ050, majority samples have certain affinity with the spilled oil. The most contaminated sediments occur at site BQ050 and the spilled oil has migrated to 8-12 cm depth. The degree of contamination can be ranked by the similarity of molecular compositions with spilled oil. Variable biomarker components in sediment extracts were also altered by ongoing biodegradation.

Serum exosomes of chronic gastritis patients infected with Helicobacter pylori mediate IL-1α expression via IL-6 trans-signalling in gastric epithelial cells

Emerging evidence has linked the exosomes to many immunological disorders, including infectious diseases. However, knowledge regarding the role of exosomes in Helicobacter pylori infection is limited. Here, we show that serum exosomes from chronic gastritis patients with H. pylori infection (Hp exosomes) stimulate the expression of the soluble interleukin (IL)-6 receptor (sIL-6R), which is involved in IL-6 trans-signalling in gastric epithelial cells. Interestingly, sIL-6R up-regulates expression of the proinflammatory cytokine IL-1α, and the neutralization of sIL-6R suppresses IL-1α secretion. Thus, Hp exosomes regulate IL-1α expression via sIL-6R-mediated IL-6 trans-signaling. Altogether, this study reveals a novel perspective in which exosomes play a vital role in immunological mechanisms during H. pylori infection.

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics - Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Fluoroquinolone antibiotics (FQs) are ubiquitous and ionisable in surface waters. Here we investigate gatifloxacin (GAT) and balofloxacin (BAL), two widely used FQs, and determine the photochemical reactivity of their respective dissociation species that arise at different pH to understand the relevance and pathways of phototransformation reactions. Simulated-sunlight experiments and matrix calculations showed that neutral forms (HFQs⁰) of the two antibiotics had the highest apparent photolytic efficiency and hydroxyl-radical oxidation reactivity. Based on the pH-dependent photochemical reactivities, the solar apparent photodegradation half-lives (t_1/2) in sunlit surface waters ranged from 14.5-169min and was 1-2 orders of magnitude faster than hydroxyl-radical induced oxidation (t_1/2=20.9-29.8h). The corresponding pathways were proposed based on the identification of key intermediates using HPLC-ESI-MS/MS. The apparent photodegradation induced defluorination, decarboxylation, and piperazinyl oxidation and rearrangement, whereas hydroxyl-radical oxidation caused hydroxylated defluorination and piperazinyl hydroxylation. The photomodified toxicity of GAT and BAL was examined using an Escherichia coli activity assay. E. coli activity was not affected by BAL, but was significantly affected by the photo-modified solutions of GAT, indicating that primary photo-degradates have a comparable or higher antibacterial activity than the parent GAT. In fresh water and seawater this antibacterial activity remained high for up to 24h, even after GAT had undergone significant photodegradation (>1 half-life), indicating the potential impact of this chemical on microbial communities in aquatic systems.

Air-Seawater Gas Exchange and Dry Deposition of Chlorinated Paraffins in a Typical Inner Sea (Liaodong Bay), North China

As a group of new persistent organic pollutants, short-chain chlorinated paraffins (SCCPs) and medium-chain CP (MCCPs) have attracted extensive worldwide interest in recent years. However, the data regarding to the environmental behavior, especially in atmospheric transfer and air-seawater exchange, are still sparse. In this study, seasonal marine boundary layer air and seawater samples were collected from Chinese Bohai sea and a fugacity model was built to evaluate the air-seawater diffusion and deposition flux of CPs. Generally, the total CP levels in atmosphere and seawater samples in summer were higher than those in spring, and CPs existed mostly in the gaseous phase in air and the dissolved phase in seawater. For SCCPs, C₁₀ and C₁₁ components were the most abundant homologue groups. For MCCPs, the C₁₄ homologue dominated in the particle phase of atmosphere and particulate phase of seawater. The logarithmic fugacity ratios (log f_a/ f_w) of higher chlorinated congeners (Cl₈ to Cl₁₀: 0.71 to 1.32 in May and 1.38 to 2.29 in August) indicated that net deposition was the predominant process, whereas lower chlorinated congeners, especially Cl₅ homologue groups in August, showed a trend of net volitization (log  f_a/ f_w < -0.5). The results of diffusion and dry deposition fluxes indicated that air-seawater gas exchange of CPs was significantly higher than dry deposition in the sampling areas.

Aqueous multivariate phototransformation kinetics of dissociated tetracycline: implications for the photochemical fate in surface waters

Antibiotics are ubiquitous pollutants in aquatic systems and can exist as different dissociated species depending on the water pH. New knowledge of their multivariate photochemical behavior (i.e., the photobehavior of different ionized forms) is needed to improve our understanding on the fate and possible remediation of these pharmaceuticals in surface and waste waters. In this study, the photochemical degradation of aqueous tetracycline (TC) and its dissociated forms (TCH₂⁰, TCH^-, and TC^2-) was investigated. Simulated sunlight experiments and matrix calculations indicated that the three dissociated species had dissimilar photolytic kinetics and photooxidation reactivities. TC^2- photodegraded the fastest due to apparent photolysis with a kinetic constant of 0.938 ± 0.021 min^-1, followed by TCH^- (0.020 ± 0.005 min^-1) and TCH₂⁰ (0.012 ± 0.001 min^-1), whereas TCH^- was found to be the most highly reactive toward •OH (105.78 ± 3.40 M^-1 s^-1), and TC^2- reacted the fastest with ¹O₂ (344.96 ± 45.07 M^-1 s^-1). Water with relatively high pH (e.g., ~ 8-9) favors the dissociated forms of TCH^- and TC^2- which are most susceptible to photochemical loss processes compared to neutral TC. The calculated corresponding environmental half-lives (t_1/2,E) in sunlit surface waters ranged from 0.05 h for pH = 9 in midsummer to 3.68 h for pH = 6 in midwinter at 45° N latitude. The process was dominated by apparent photolysis (especially in summer, 62-91%), followed by ¹O₂ and •OH oxidation. Adjusting the pH to slightly alkaline conditions prior to UV or solar UV light treatment may be an effective way of enhancing the photochemical removal of TC from contaminated water. Graphical abstract Aqueous multiple photochemical behavior of dissociated tetracycline (TCH₂⁰, TCH^-, and TC^2-) is first comprehensively reported on revealing the phototransformation kinetics and implications for the fate in surface waters.

Occurrence and distribution of perfluoroalkyl substances (PFASs) in the water dissolved phase and suspended particulate matter of the Dalian Bay, China

In the present study, the contamination level and spatial distribution of PFASs in the water dissolved phase and suspended particulate matter (SPM) phase of the Dalian Bay, and the SPM-water partition behavior were investigated. The total concentrations of PFASs (∑PFASs) in the water dissolved phase ranged from 6.9 to 17.1 ng L^-1, with perfluorooctanoic acid (PFOA), perfluorobutanoic acid, and perfluorobutane sulfonate (PFBS) as the predominant PFASs, while ∑PFASs in SPM ranged from 1.7 to 27.5 ng g^-1 dw with higher contributions from PFBS, perfluorooctane sulfonic acid and PFOA. As for the pollution distribution, the concentrations of PFASs inside the Dalian Bay were higher than those outside the bay. For perfluoroalkyl carboxylic acid (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), the suspended particulate matter-water partition coefficient (log K_d) values ranged from 2.62 to 3.76, and from 3.39 to 3.56, respectively. The log K_d values of PFASs generally increased with the increasing perfluorinated carbon chain length. Short-chain PFCAs were mostly detected in the water dissolved phase, while long-chain PFCAs and PFSAs appeared to bind more strongly to SPM phase. The contamination level of long-chain PFCAs and PFSAs could be underestimated if only the water dissolved phase were measured. Therefore, further investigations should consider the role of SPM on the environmental behavior and fate of PFASs in the aquatic environment.

Characterization of Brominated Disinfection Byproducts Formed During the Chlorination of Aquaculture Seawater

Although brominated disinfection byproducts (Br-DBPs) have been reported to form from reactions between bromide, dissolved organic matter (DOM), and disinfectants, their formation during the disinfection of aquaculture seawater via chlorination has been rarely studied. Herein, after 5 days of disinfection of raw aquaculture seawater samples with sodium dichloroisocyanurate (NaDDC), trichloroisocyanuric acid (TCCA) and chlorine dioxide (ClO₂), 181, 179, and 37 Br-DBPs were characterized by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Sunlight irradiation of the chlorinated aquaculture seawater with TCCA and NaDDC was found to reduce the formation of Br-DBPs, possibly due to the photodegradation of the important HBrO/HClO intermediate and the degradation of formed Br-DBPs. The formation of Br-DBPs chlorinated by ClO₂ increased under sunlight irradiation. The number of Br-DBPs formed during chlorination processes agreed well with the total organic bromine (TOBr) content measured by inductively coupled plasma mass spectrometry (ICP-MS). Most of the Br-DBPs were highly unsaturated and phenolic compounds, which were primarily generated through electrophilic substitution by bromine coupled with other reactions. In addition, some emerging aromatic Br-DBPs with high relative intensities were also assigned, and these compounds might be highly lipophilic and could potentially accumulate in marine organisms. Our findings call for further focus on and investigation of the Br-DBPs produced in chlorinated aquaculture seawater.

High-level expression and characterization of a new κ-carrageenase from marine bacterium Pedobacter hainanensis NJ-02

A novel κ-carrageenase gene (CgkB) has been cloned from Pedobacter hainanensis NJ-02 and expressed heterologously in Escherichia coli BL21 (DE3). It consisted of 1935 bp and encoded 644 amino acid residues with a molecular weight of 71·61 kDa. The recombinant enzyme showed maximal activity of 2458 U mg^-1 at 40°C and pH 8·0. Additionally, it could retain more than 70% of its maximal activity after being incubated at pH of 5·5-10·0 below 40°C. K⁺ and a broad range of NaCl can activate the enzyme. The K_m and V_max of CgkB was 2·4 mg ml^-1 and 126 mmol mg^-1  min^-1 . The ESI-MS analysis of hydrolysates indicated that the enzyme can endolytically depolymerize the carrageenan into tetrasaccharides and hexasaccharides. The results indicated that the enzyme with high activity could be a valuable enzyme tool to produce carrageenan oligosaccharides with various activities.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enzymatic preparation of carrageenan oligosaccharides has drawn increased attention due to their various physiological activities. It is urgent to explore enzyme tools with higher activity and better stability. In this work, a novel κ-carrageenase was identified and characterized from marine bacterium Pedobacter hainanensis NJ-02. The enzyme with high activity could be a valuable tool to produce carrageenan oligosaccharides with various activities.

Novel MBTPS2 missense mutation causes a keratosis follicularis spinulosa decalvans phenotype: mutation update and review of the literature

Keratosis follicularis spinulosa decalvans (KFSD) is an X-linked condition characterized by keratotic follicular papules and progressive alopecia, which is caused by mutations in the MBTPS2 gene. We carried out a genetic study on a child who was suspected clinically to have KFSD. Sanger sequencing was performed to detect mutations in the entire coding region of MBTPS2. A novel missense mutation (c.599C>T) was identified in the patient, confirming a diagnosis of KFSD. We reviewed related cases with MBTPS2 mutations for evidence of genotype-phenotype correlations.

The effect of environmental factors and migration dynamics on the prevalence of antibiotic-resistant Escherichia coli in estuary environments

Understanding the antibiotic resistance transmission mechanisms and migration dynamics of antibiotic-resistant bacteria (ARB) in the natural environment is critical given the increasing prevalence of antibiotic resistance. The aim of this study was to examine the fate of sulfonamide-resistant fecal bacteria (E. coli) in an estuary ecosystem and to explore the role and contribution of environmental factors in this process. The prevalence of sulfonamide-resistance status of E. coli was analyzed over different seasons in two estuary systems. Environmental factors and disturbance indices of anthropogenic activities were evaluated by detecting antibiotic concentrations, heavy metal abundance and other physicochemical parameters. The abundances of antibiotic-resistant E. coli were significantly attenuated during land-sea migration suggesting that estuary environments play a natural mitigation role in the contamination of freshwaters by antibiotic-resistant E. coli. Additionally, environmental factors and disturbance indices of anthropogenic activities significantly correlated with the distribution and migration of antibiotic-resistant E. coli in the estuaries. Lastly, simulation experiments suggested differential adaptability between antibiotic-resistant and non-resistant E. coli towards environmental changes in estuary environments. Meanwhile, our results indicate that low concentrations of antibiotics will not increase the competitive advantage of resistant E. coli in estuaries.

Gestational diabetes care and outcomes for refugee women: a population-based cohort study

AIM

To determine the prevalence of adverse clinical outcomes, the rates of healthcare utilization, and the incidence of post-partum Type 2 diabetes in refugees with gestational diabetes (GDM), compared with other immigrants and non-immigrants.

METHODS

A population-based cohort study was conducted using healthcare databases in Ontario, Canada. Over 40 000 women with GDM having singleton live births between 2002 and 2014 were identified. We identified GDM adverse outcomes such as macrosomia, pre-eclampsia and respiratory distress syndrome. Antenatal and newborn healthcare utilization were ascertained. Women were then followed for diagnosis of diabetes post-partum.

RESULTS

Both refugees and other immigrants had a lower rate than non-immigrants of many adverse GDM outcomes, including pre-eclampsia [relative risk (RR) 0.65, 95% confidence interval (95% CI) 0.44-0.95 and 0.61, 95% CI 0.52-0.72, respectively], preterm birth (RR 0.87, 95% CI 0.75-0.995 and 0.85, 95% CI 0.80-0.91, respectively), and respiratory distress syndrome (RR 0.83, 95% CI 0.70-0.97 and 0.78, 95% CI 0.72-0.84, respectively). However, refugees were less likely to attend well-baby care in time for the first routine vaccination (RR 0.92, 95% CI 0.88-0.95). Incidence of post-partum diabetes was high in all groups, but refugee women were at increased risk (hazard ratio 1.23, 95% CI 1.11-1.37).

CONCLUSIONS

Despite different circumstances leading to migration, refugees have a similar 'healthy immigrant effect' to other immigrants, with respect to adverse GDM outcomes. However, newborns of refugees were less likely to have well-baby care, and refugee women were also at especially high risk of developing diabetes post-partum. These are both important public health issues.

Simultaneous Remote Observations of Intense Reconnection Effects by DMSP and MMS Spacecraft During a Storm Time Substorm

During a magnetic storm on 23 June 2015, several very intense substorms took place, with signatures observed by multiple spacecraft including DMSP and Magnetospheric Multiscale (MMS). At the time of interest, DMSP F18 crossed inbound through a poleward expanding auroral bulge boundary at 23.5 h magnetic local time (MLT), while MMS was located duskward of 22 h MLT during an inward crossing of the expanding plasma sheet boundary. The two spacecraft observed a consistent set of signatures as they simultaneously crossed the reconnection separatrix layer during this very intense reconnection event. These include (1) energy dispersion of the energetic ions and electrons traveling earthward, accompanied with high electron energies in the vicinity of the separatrix; (2) energy dispersion of polar rain electrons, with a high-energy cutoff; and (3) intense inward convection of the magnetic field lines at the MMS location. The high temporal resolution measurements by MMS provide unprecedented observations of the outermost electron boundary layer. We discuss the relevance of the energy dispersion of the electrons, and their pitch angle distribution, to the spatial and temporal evolution of the boundary layer. The results indicate that the underlying magnetotail magnetic reconnection process was an intrinsically impulsive and the active X-line was located relatively close to the Earth, approximately at 16-18 R_E.