Using blood lead concentrations of wildlife sentinels to identify environmental risk factors of lead exposure for public health and wildlife rehabilitation efforts.

Lead poisoning remains a persistent health issue for both humans and wildlife, despite strides to reduce lead contamination in the environment. Using Geographic Information Systems (GIS), this study explores the associations between blood lead levels (BLLs) in wildlife sentinels and possible built environment lead exposure risk factors in the Minneapolis-Saint Paul, Minnesota urban area. Results show a high-level of heterogeneity in animal BLLs (n = 472) across our urban environment and suggest that each kilometer increase in road density is associated with a 17.07% (95% CI: 1.48%, 35.05%) increase in BLL in our study species of Virginia opossums and Eastern gray squirrels, and a 14.28% (95% CI: 1.16%, 29.09%) increase in BLL of rock pigeons. For squirrels and opossums, we see an additional 5.72% (95% CI: 0.59%, 10.85%) increased risk of BLL for every 1000 people per square-mile. The relationship between animal sentinels and environmental hazards can give us an insight into the potential lead exposure risks for humans. The use of wildlife sentinel data to explore environmental risk factors supports a One Health approach to better address public health questions and aid in wildlife rehabilitation related to residual lead poisoning from ambient environmental exposures.

Using advanced racial and ethnic identity demographics to improve surveillance of work-related conditions in an occupational clinic setting.

BACKGROUND: Although racial and ethnic identities are associated with a multitude of disparate medical outcomes, surveillance of these subpopulations in the occupational clinic setting could benefit enormously from a more detailed and nuanced recognition of racial and ethnic identity. METHODS: The research group designed a brief questionnaire to capture several dimensions of this identity and collected data from patients seen for work-related conditions in four occupational medicine clinics from May 2019 through March 2020. Responses were used to calculate the sensitivity and specificity of extant racial/ethnic identity data within our electronic health records system, and were compared to participants' self-reported industry and occupation, coded according to North American Industry Classification System and Standard Occupational Classification System listings. RESULTS: Our questionnaire permitted collection of data that defined our patients' specific racial/ethnic identity with far greater detail, identified patients with multiple ethnic identities, and elicited their preferred language. Response rate was excellent (94.2%, n = 773). Non-White participants frequently selected a racial/ethnic subcategory (78.1%-92.2%). Using our race/ethnicity data as a referent, the electronic health record (EHR) had a high specificity (>87.1%), widely variable sensitivity (11.8%-82.2%), and poorer response rates (75.1% for race, 82.5% for ethnicity, as compared to 93.8% with our questionnaire). Additional analyses revealed some industries and occupations disproportionately populated by patients of particular racial/ethnic identities. CONCLUSIONS: Our project demonstrates the usefulness of a questionnaire which more effectively identifies racial/ethnic subpopulations in an occupational medicine clinic, permitting far more detailed characterization of their occupations, industries, and diagnoses.

Periplasmic superoxide dismutase SodCI of Salmonella binds peptidoglycan to remain tethered within the periplasm.

Salmonellae survive and propagate in macrophages to cause serious systemic disease. Periplasmic superoxide dismutase plays a critical role in this survival by combating phagocytic superoxide. Salmonella Typhimurium strain 14028 produces two periplasmic superoxide dismutases: SodCI and SodCII. Although both proteins are produced during infection, only SodCI is functional in the macrophage phagosome. We have previously shown that SodCI, relative to SodCII, is both protease resistant and tethered within the periplasm and that either of these properties is sufficient to allow a SodC to protect against phagocytic superoxide. Tethering is defined as remaining cell-associated after osmotic shock or treatment with cationic antimicrobial peptides. Here we show that SodCI non-covalently binds peptidoglycan. SodCI binds to Salmonella and Bacillus peptidoglycan, but not peptidoglycan from Staphylococcus. Moreover, binding can be inhibited by a diaminopimelic acid containing tripeptide, but not a lysine containing tripeptide, showing that the protein recognizes the peptide portion of the peptidoglycan. Replacing nine amino acids in SodCII with the corresponding residues from SodCI confers tethering, partially delineating an apparently novel peptidoglycan binding domain. These changes in sequence increase the affinity of SodCII for peptidoglycan fragments to match that of SodCI and allow the now tethered SodCII to function during infection.

Either periplasmic tethering or protease resistance is sufficient to allow a SodC to protect Salmonella enterica serovar Typhimurium from phagocytic superoxide.

Salmonella Typhimurium combats phagocytic superoxide by producing the periplasmic superoxide dismutase, SodCI. The homologous protein, SodCII, is also produced during infection, but does not contribute to virulence. The proteins physically differ in that SodCI is dimeric, protease resistant and non-covalently tethered within the periplasm. Conversely, SodCII is a protease-sensitive monomer that is released normally from the periplasm by osmotic shock. To identify which properties correlate with virulence, we constructed over 20 enzymatically functional hybrid SodC proteins and assayed them for protease susceptibility, release by osmotic shock, multimerization and affinity for metal cofactors. Protease susceptibility maps to the C-terminus of SodCII, while SodCI residues 120-131 are required for tethering. A protease-resistant SodCII hybrid was able to substitute for SodCI during infection. Interestingly, a tethered but protease-sensitive SodCII hybrid was also able to confer protection. Thus, either tethering or protease resistance is sufficient for a SodC to function during infection. These results support our model that in the macrophage, the outer membrane of Salmonella is partially disrupted by antimicrobial peptides. Periplasmic proteins, including SodCII, are released and/or phagocytic proteases gain access. SodCI is both tethered within the periplasm and protease resistant, thereby surviving to detoxify superoxide.