C-type lectin 4 of Toxocara canis activates NF-ĸB and MAPK pathways by modulating NOD1/2 and RIP2 in murine macrophages in vitro.

Toxocara canis is a parasitic zoonose that is distributed worldwide and is one of the two pathogens causing toxocariasis. After infection, it causes serious public health and safety problems, which pose significant veterinary and medical challenges. To better understand the regulatory effects of T. canis infection on the host immune cells, murine macrophages (RAW264.7) were incubated with recombinant T. canis C-type lectin 4 (rTc-CTL-4) protein in vitro. The quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to analyze the nucleotide-binding oligomerization domain-containing protein 1/2 (NOD1/2), receptor-interacting protein 2 (RIP2), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), and mitogen-activated protein kinase (MAPK) on mRNA level and protein expression level in macrophages. Our results indicated that 10 µg/mL rTc-CTL-4 protein could modulate the expression of NOD1, NOD2, and RIP2 at both the transcriptional and translational levels. The protein translation levels of NF-κB, P-p65, p38, and P-p38 in macrophages were also modulated by rTc-CTL-4 protein. Macrophages were co-incubated with rTc-CTL-4 protein after siRNA silencing of NOD1, NOD2, and RIP2. The expression levels of NF-κB, P-p65, p38, and P-p38 were significantly changed compared with the negative control groups (Neg. Ctrl.). Taken together, rTc-CTL-4 protein seemed to act on NOD1/2-RIP2-NF-κB and MAPK signaling pathways in macrophages and might activate MAPK and NF-κB signaling pathways by regulating NOD1, NOD2, and RIP2. The insights from the above studies could contribute to our understanding of immune recognition and regulatory mechanisms of T. canis infection in the host animals.

Intermittent Oxygen Supply Facilitates Codegradation of Trichloroethene and Toluene by Anaerobic Consortia.

Biodegradation is commonly employed for remediating trichloroethene- or toluene-contaminated sites. However, remediation methods using either anaerobic or aerobic degradation are inefficient for dual pollutants. We developed an anaerobic sequencing batch reactor system with intermittent oxygen supply for the codegradation of trichloroethylene and toluene. Our results showed that oxygen inhibited anaerobic dechlorination of trichloroethene, but dechlorination rates remained comparable to that at dissolved oxygen levels of 0.2 mg/L. Intermittent oxygenation engendered reactor redox fluctuations (-146 to -475 mV) and facilitated rapid codegradation of targeting dual pollutants, with trichloroethene degradation constituting only 27.5% of the noninhibited dechlorination. Amplicon sequencing analysis revealed the predominance of Dehalogenimonas (16.0% ± 3.5%) over Dehalococcoides (0.3% ± 0.2%), with ten times higher transcriptomic activity in Dehalogenimonas. Shotgun metagenomics revealed numerous genes related to reductive dehalogenases and oxidative stress resistance in Dehalogenimonas and Dehalococcoides, as well as the enrichment of diversified facultative populations with functional genes related to trichloroethylene cometabolism and aerobic and anaerobic toluene degradation. These findings suggested that the codegradation of trichloroethylene and toluene may involve multiple biodegradation mechanisms. Overall results of this study demonstrate the effectiveness of intermittent micro-oxygenation in aiding trichloroethene-toluene degradation, suggesting the potential for the bioremediation of sites with similar organic pollutants.

Determination of trace metals in seawater by an automated flow injection ion chromatograph pretreatment system with ICPMS.

A novel flow injection ion chromatograph (FI-IC) system has been developed to fully automate pretreatment procedures for multi-elemental analysis of trace metals in seawater by inductively coupled plasma mass spectrometer (ICPMS). By combining 10-port, 2 position and 3-way valves in the FI-IC manifold, the system effectively increase sample throughput by simultaneously processing three seawater samples online for: sample loading, injection, buffering, preconcentration, matrix removal, metal elution, and sample collection. Forty-two seawater samples can be continuously processed without any manual handing. Each sample pretreatment takes about 10 min by consuming 25 mL of seawater and producing 5 mL of processed concentrated samples for multi-elemental offline analysis by ICPMS. The offline analysis improve analytical precision and significantly increase total numbers of isotopes determined by ICPMS, which include the metals Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, and Zn. The blank value and detection limits of trace metals using the system with ICPMS analysis all range from 0.1 to 10 parts per trillion (ppt), except Al, Fe, and Zn. The accuracy of the pretreatment system was validated by measuring open-ocean and coastal reference seawater, NASS-5 and CASS-4. Using the system with ICPMS analysis, we have obtained reliable trace metal concentrations in the water columns of the South China Sea. Possessing the features of full automation, high throughput, low blank, and low reagent volume used, the system automates and simplifies rigorous and complicated pretreatment procedures for multi-elemental analysis of trace metals in seawater and effectively enhances analytical capacity for trace metal analysis in environmental and seawater samples.