Alternative Complement Activity in the Egg Cytosol of Amphioxus Branchiostoma belcheri: Evidence for the Defense Role of Maternal Complement Components

Background: The eggs in most invertebrates are fertilized externally, and therefore their resulting embryos are exposed to an environment full of microbes, many of which are pathogens capable of killing other organisms. How the developing embryos of invertebrates defend themselves against pathogenic attacks is an intriguing question to biologists, and remains largely unknown. Methodology/Principal Findings: Here we clearly demonstrated that the egg cytosol prepared from the newly fertilized eggs of amphioxus Branchiostoma belcheri, an invertebrate chordate, was able to inhibit the growth of both the Gramnegative bacterium Vibrio anguillarum and the Gram-positive bacterium Staphylococcus aureus. All findings point to that it is the complement system operating via the alternative pathway that is attributable to the bacteriostatic activity. Conclusions/Significance: This appears to be the first report providing the evidence for the functional role of the maternal complement components in the eggs of invertebrate species, paving the way for the study of maternal immunity in other invertebrate organisms whose eggs are fertilized in vitro. It also supports the notion that the early developing embryo

40 Years of Weathering of Coastal Oil Residues in the Southern Gulf of Mexico

The oil spill from the Ixtoc 1 well in 1979 in the southern Gulf of Mexico (sGoM) was in many aspects very similar to the Deepwater Horizon (DWH) blowout offshore Louisiana 30 years later (2010), most importantly because of the subsurface nature of the oil release, the amount of oil released, and the extensive environmental distribution of the spilled oil, including coastal impacts. Because of that, the Ixtoc 1 spill can serve as an excellent analog to study and model the long-term oil weathering processes in coastal environments. In 2016, a research expedition sponsored by the Gulf of Mexico Research Initiative (GoMRI) visited many coastal sites in the sGoM, previously known to be impacted by the Ixtoc 1 spill, and collected oil residues. The residues were analyzed using targeted (GC-MS/MS) and non-targeted (FTICR-MS) approaches in order to assess their origin and the nature of weathering transformation products. The initial results suggest multi-decadal preservation potential of Ixtoc 1 spill residues in certain low-energy environments, such as coastal mangrove forests. These results provide valuable input for the modelling of long-term fate and impacts of the DWH spill

Applications of FTICR-MS in Oil Spill Studies

During the past decade, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has been established as a technique of choice for the comprehensive chemical assessment of some of the most complex organic mixtures, such as petroleum, or dissolved organic matter. In the aftermath of the Deepwater Horizon (DWH) blowout, FTICR-MS demonstrated its applicability for the characterization of oil spill residues produced by abiotic weathering, such as photooxidation, and/or microbial processes and interactions, for example, marine oil snow aggregation. Such residues are abundant in high molecular weight, polar, and heteroatom-bearing chemical species, which cannot be analyzed by the typical oil spill forensics tools such as gas chromatography. Therefore, the expansion of the analytical window afforded by FTICR-MS is crucial for the monitoring and understanding of long-term oil spill fate. Furthermore, capability of FTICR-MS to characterize non-hydrocarbon petroleum fractions will be very important in the case of potential future spills of heavy, unconventional oils, such as bitumen