Potential for Glove Risk Amplification via Direct Physical, Chemical, and Microbiological Contamination.

This review focuses on the potential direct physical, chemical, and microbiological contamination from disposable gloves when utilized in food environments, inclusive of the risks posed to food products as well as worker safety. Unrecognized problems endemic to glove manufacturing were magnified during the COVID-19 pandemic due to high demand, increased focus on PPE performance, availability, supply chain instability, and labor shortages. Multiple evidence-based reports of contamination, toxicity, illness, deaths, and related regulatory action linked to contaminated gloves in food and healthcare have highlighted problems indicative of systemic glove industry shortcomings. The glove manufacturing process was diagramed with sources and pathways of contamination identified, indicating weak points with documented occurrences detailed. Numerous unsafe ingredients can introduce chemical contaminants, potentially posing risks to food and to glove users. Microbial hazards present significant challenges to overall glove safety as contaminants appear to be introduced via polluted water sources or flawed glove manufacturing processes, resulting in increased risks within food and healthcare environments. Frank and opportunistic pathogens along with food spoilage organisms can be introduced to foods and wearers. When the sources and pathways of glove-borne contamination were explored, it was found that physical failures play a pivotal role in the release of sweat build-up, liquefaction of chemical residues, and incubation of microbial contaminants from hands and gloves. Thus, with glove physical integrity issues, including punctures in new, unused gloves that can develop into significant rips and tears, not only can direct physical food contamination occur but also chemical and microbiological contamination can find their way into food. Enhanced regulatory requirements for Acceptable Quality Limits of food-grade gloves, and the establishment of appropriate bioburden standards would enhance safety in food applications. Based on the information provided, together with a false sense of security associated with glove use, the unconditional belief in glove chemical and microbiological purity may be unfounded.

The Interaction between the Third Type III Domain from Fibronectin and Anastellin Involves ß-Strand Exchange.

Anastellin is a small recombinant fragment derived from the extracellular matrix protein fibronectin; it comprises the first type III (FN3) domain without the two N-terminal ß-strands. It inhibits angiogenesis, tumor growth, and metastasis in mouse models and requires endogenous fibronectin for its in vivo anti-angiogenic activity. It binds to fibronectin in vitro and converts the soluble protein to insoluble fibrils that structurally and functionally resemble fibronectin fibrils deposited in the extracellular matrix by cells. Anastellin binds to several FN3 domains in fibronectin, but how it interacts with these domains and why the interactions lead to aggregation of fibronectin are not well understood. In this work, we investigated the interaction between anastellin and the third FN3 domain (3FN3) from fibronectin. We show that anastellin binds with high affinity to a peptide comprising the two N-terminal ß-strands from 3FN3, and we present here the structure of the resulting complex. The peptide and anastellin form a composite FN3 domain, with the two N-terminal ß-strands from 3FN3 bound in place of the two ß-strands that are missing in anastellin. We also demonstrate using disulfide cross-linking that a similar interaction involving the two N-terminal ß-strands of 3FN3 occurs when intact 3FN3 binds to anastellin. 3FN3 adopts a compact globular fold in solution, and to interact with anastellin in a manner consistent with our data, it has to open up and expose a ß-strand edge that is not accessible in the context of the folded domain.

Structural studies of E73 from a hyperthermophilic archaeal virus identify the "RH3" domain, an elaborated ribbon-helix-helix motif involved in DNA recognition.

Hyperthermophilic archaeal viruses, including Sulfolobus spindle-shaped viruses (SSVs) such as SSV-1 and SSV-Ragged Hills, exhibit remarkable morphology and genetic diversity. However, they remain poorly understood, in part because their genomes exhibit limited or unrecognizable sequence similarity to genes with known function. Here we report structural and functional studies of E73, a 73-residue homodimeric protein encoded within the SSV-Ragged Hills genome. Despite lacking significant sequence similarity, the nuclear magnetic resonance (NMR) structure reveals clear similarity to ribbon-helix-helix (RHH) domains present in numerous proteins involved in transcriptional regulation. In vitro double-stranded DNA (dsDNA) binding experiments confirm the ability of E73 to bind dsDNA in a nonspecific manner with micromolar affinity, and characterization of the K11E variant confirms the location of the predicted DNA binding surface. E73 is distinct, however, from known RHH domains. The RHH motif is elaborated upon by the insertion of a third helix that is tightly integrated into the structural domain, giving rise to the "RH3" fold. Within the homodimer, this helix results in the formation of a conserved, symmetric cleft distal to the DNA binding surface, where it may mediate protein-protein interactions or contribute to the high thermal stability of E73. Analysis of backbone amide dynamics by NMR provides evidence of a rigid core, fast picosecond to nanosecond time scale NH bond vector motions for residues located within the antiparallel ß-sheet region of the proposed DNA-binding surface, and slower microsecond to millisecond time scale motions for residues in the α1-α2 loop. The roles of E73 and its SSV homologues in the viral life cycle are discussed.

(1)H, (13)C, (15)N backbone and side chain NMR resonance assignments for E73 from Sulfolobus spindle-shaped virus ragged hills, a hyperthermophilic crenarchaeal virus from Yellowstone National Park.

Crenarchaeal viruses are commonly found in hyperthermal acidic environments such as those of Yellowstone National Park. These remarkable viruses not only exhibit unusual morphologies, but also display extreme genetic diversity. However, little is known about crenarchaeal viral life cycles, virus-host interactions, and their adaptation to hyperthermophilic environments. In an effort to better understand the functions of crenarchaeal viruses and the proteins encoded by their genomes, we have undertaken detailed structural and functional studies of gene products encoded in the open reading frames of Sulfolobus spindle-shaped virus ragged hills. Herein, we report ((15)N, (13)C, (1)H) resonance assignments of backbone and side chain atoms of a 19.1 kDa homodimeric E73 protein of SSVRH.