Pulmonary toxicity and lung tumorigenic potential of surrogate metal oxides in gas metal arc welding–stainless steel fume: Iron as a primary mediator versus chromium and nickel

In 2017, the International Agency for Research on Cancer classified welding fumes as “car- cinogenic to humans” (Group 1). Both mild steel (MS) welding, where fumes lack carcino- genic chromium and nickel, and stainless steel (SS) increase lung cancer risk in welders; therefore, further research to better understand the toxicity of the individual metals is needed. The objectives were to (1) compare the pulmonary toxicity of chromium (as Cr(III) oxide [Cr2O3] and Cr (VI) calcium chromate [CaCrO4]), nickel [II] oxide (NiO), iron [III] oxide (Fe2O3), and gas metal arc welding-SS (GMAW-SS) fume; and (2) determine if these metal oxides can promote lung tumors. Lung tumor susceptible A/J mice (male, 4–5 weeks old) were exposed by oropharyngeal aspiration to vehicle, GMAW-SS fume (1.7 mg), or a low or high dose of surrogate metal oxides based on the respective weight percent of each metal in the fume: Cr2O3 + CaCrO4 (366 + 5 μg and 731 + 11 μg), NiO (141 and 281 μg), or Fe2O3 (1 and 2 mg). Bronchoalveolar lavage, histopathology, and lung/liver qPCR were done at 1, 7, 28, and 84 days post-aspiration. In a two-stage lung carcinogenesis model, mice were initi- ated with 3-methylcholanthrene (10 μg/g; intraperitoneal; 1x) or corn oil then exposed to metal oxides or vehicle (1 x/week for 5 weeks) by oropharyngeal aspiration. Lung tumors were counted at 30 weeks post-initiation. Results indicate the inflammatory potential of the metal oxides was Fe2O3 \u3e Cr2O3 + CaCrO4 \u3e NiO. Overall, the pneumotoxic effects were negligible for NiO, acute but not persistent for Cr2O3 + CaCrO4, and persistent for the Fe2O3 exposures. Fe2O3, but not Cr2O3 + CaCrO4 or NiO significantly promoted lung tumors. These results provide experimental evidence that Fe2O3 is an important mediator of welding fume toxicity and support epidemiological findings and the IARC classification

Report on the 2013: Rapid assessment survey of marine species at New England Bays and Harbors

Introduced species (i.e., non-native species that have become established in\ud a new location) have increasingly been recognized as a concern as they have\ud become more prevalent in marine and terrestrial environments (Mooney and\ud Cleland 2001; Simberloff et al. 2005). The ability of introduced species to alter\ud population, community, and ecosystem structure and function, as well as\ud cause significant economic damage is well documented (Carlton 1989, 1996b,\ud 2000; Cohen and Carlton 1995; Cohen et al. 1995; Elton 1958; Meinesz et al.\ud 1993; Occhipinti-Ambrogi and Sheppard 2007; Pimentel et al. 2005; Thresher\ud 2000). The annual economic costs incurred from managing the approximately\ud 50,000 introduced species in the United States alone are estimated to be over\ud $120 billion (Pimentel et al. 2005).\ud Having a monitoring network in place to track new introductions and\ud distributional changes of introduced species is critical for effective\ud management, as these efforts may be more successful when species are\ud detected before they have the chance to become established. A rapid\ud assessment survey is one such method for early detection of introduced\ud species. With rapid assessment surveys, a team of taxonomic experts\ud record and monitor marine species–providing a baseline inventory of\ud native, introduced, and cryptogenic (i.e., unknown origin) species (as\ud defined by Carlton 1996a)–and document range expansions of previously\ud identified species.\ud Since 2000, five rapid assessment surveys have been conducted in New\ud England. These surveys focus on recording species at marinas, which often\ud are in close proximity to transportation vectors (i.e., recreational boats).\ud Species are collected from floating docks and piers because these structures\ud are accessible regardless of the tidal cycle. Another reason for sampling floating\ud docks and other floating structures is that marine introduced species are often\ud found to be more prevalent on artificial surfaces than natural surfaces (Glasby\ud and Connell 2001; Paulay et al. 2002). The primary objectives of these surveys\ud are to: (1) identify native, introduced, and cryptogenic marine species,\ud (2) expand on data collected in past surveys, (3) assess the introduction status\ud and range extensions of documented introduced species, and (4) detect new\ud introductions. This report presents the introduced, cryptogenic, and native\ud species recorded during the 2013 survey.CZM through NOAA NA13NOS4190040MIT Sea Grant through NOAA NA10OAR4170086

Increased Inter-Colony Fusion Rates Are Associated with Reduced COI Haplotype Diversity in an Invasive Colonial Ascidian Didemnum vexillum

Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species

An expanded inventory of conserved meiotic genes provides evidence for sex in Trichomonas vaginalis.

Meiosis is a defining feature of eukaryotes but its phylogenetic distribution has not been broadly determined, especially among eukaryotic microorganisms (i.e. protists)-which represent the majority of eukaryotic 'supergroups'. We surveyed genomes of animals, fungi, plants and protists for meiotic genes, focusing on the evolutionarily divergent parasitic protist Trichomonas vaginalis. We identified homologs of 29 components of the meiotic recombination machinery, as well as the synaptonemal and meiotic sister chromatid cohesion complexes. T. vaginalis has orthologs of 27 of 29 meiotic genes, including eight of nine genes that encode meiosis-specific proteins in model organisms. Although meiosis has not been observed in T. vaginalis, our findings suggest it is either currently sexual or a recent asexual, consistent with observed, albeit unusual, sexual cycles in their distant parabasalid relatives, the hypermastigotes. T. vaginalis may use meiotic gene homologs to mediate homologous recombination and genetic exchange. Overall, this expanded inventory of meiotic genes forms a useful "meiosis detection toolkit". Our analyses indicate that these meiotic genes arose, or were already present, early in eukaryotic evolution; thus, the eukaryotic cenancestor contained most or all components of this set and was likely capable of performing meiotic recombination using near-universal meiotic machinery