Disinfection of football protective equipment using chlorine dioxide produced by the ICA TriNova system

<p>Abstract</p> <p>Backround</p> <p>Community-associated methicillin-resistant <it>Staphylococcus aureus </it>outbreaks have occurred in individuals engaged in athletic activities such as wrestling and football. Potential disease reduction interventions include the reduction or elimination of bacteria on common use items such as equipment. Chlorine dioxide has a long history of use as a disinfectant. The purpose of this investigation was to evaluate the ability of novel portable chlorine dioxide generation devices to eliminate bacteria contamination of helmets and pads used by individuals engaged in football.</p> <p>Methods</p> <p>In field studies, the number of bacteria associated with heavily used football helmets and shoulder pads was determined before and after overnight treatment with chlorine dioxide gas. Bacteria were recovered using cotton swabs and plated onto trypticase soy agar plates. In laboratory studies, <it>Staphylococcus aureus </it>was applied directly to pads. The penetration of bacteria into the pads was determined by inoculating agar plates with portions of the pads taken from the different layers of padding. The ability to eliminate bacteria on the pad surface and underlying foam layers after treatment with chlorine dioxide was also determined.</p> <p>Results</p> <p>Rates of recovery of bacteria after treatment clearly demonstrated that chlorine dioxide significantly (p < 0.001) reduce and eliminated bacteria found on the surface of pads. For example, the soft surface of shoulder pads from a university averaged 2.7 × 10³recoverable bacteria colonies before chlorine dioxide treatment and 1.3 × 10²recoverable colonies after treatment. In addition, the gas was capable of penetrating the mesh surface layer and killing bacteria in the underlying foam pad layers. Here, 7 × 10³to 4.5 × 10³laboratory applied <it>S. aureus </it>colonies were recovered from underlying layers before treatment and 0 colonies were present after treatment. Both naturally occurring bacteria and <it>S. aureus </it>were susceptible to the treatment process.</p> <p>Conclusion</p> <p>Results of this study have shown that chlorine dioxide can easily and safely be used to eliminate bacteria contamination of protective pads used by football players. This could serve to reduce exposure to potential pathogens such as the methicillin-resistant <it>Staphylococcus aureus </it>among this group of individuals.</p

Mobilization of HIV Spread by Diaphanous 2 Dependent Filopodia in Infected Dendritic Cells

Paramount to the success of persistent viral infection is the ability of viruses to navigate hostile environments en route to future targets. In response to such obstacles, many viruses have developed the ability of establishing actin rich-membrane bridges to aid in future infections. Herein through dynamic imaging of HIV infected dendritic cells, we have observed how viral high-jacking of the actin/membrane network facilitates one of the most efficient forms of HIV spread. Within infected DC, viral egress is coupled to viral filopodia formation, with more than 90% of filopodia bearing immature HIV on their tips at extensions of 10 to 20 µm. Live imaging showed HIV filopodia routinely pivoting at their base, and projecting HIV virions at µm.sec−1 along repetitive arc trajectories. HIV filopodial dynamics lead to up to 800 DC to CD4 T cell contacts per hour, with selection of T cells culminating in multiple filopodia tethering and converging to envelope the CD4 T-cell membrane with budding HIV particles. Long viral filopodial formation was dependent on the formin diaphanous 2 (Diaph2), and not a dominant Arp2/3 filopodial pathway often associated with pathogenic actin polymerization. Manipulation of HIV Nef reduced HIV transfer 25-fold by reducing viral filopodia frequency, supporting the potency of DC HIV transfer was dependent on viral filopodia abundance. Thus our observations show HIV corrupts DC to CD4 T cell interactions by physically embedding at the leading edge contacts of long DC filopodial networks

Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq

We present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784 ($\mathrm{D}\approx31$ Mpc), from $<1$ to 180 days after explosion. The high-cadence observations of SN 2022xkq, a photometrically transitional and spectroscopically 91bg-like SN Ia, cover the first days and weeks following explosion which are critical to distinguishing between explosion scenarios. The early light curve of SN 2022xkq has a red early color and exhibits a flux excess which is more prominent in redder bands; this is the first time such a feature has been seen in a transitional/91bg-like SN Ia. We also present 92 optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a long-lived C I 1.0693 $\mu$m feature which persists until 5 days post-maximum. We also detect C II $\lambda$6580 in the pre-maximum optical spectra. These lines are evidence for unburnt carbon that is difficult to reconcile with the double detonation of a sub-Chandrasekhar mass white dwarf. No existing explosion model can fully explain the photometric and spectroscopic dataset of SN 2022xkq, but the considerable breadth of the observations is ideal for furthering our understanding of the processes which produce faint SNe Ia.Comment: 38 pages, 16 figures, accepted for publication in ApJ, the figure 15 input models and synthetic spectra are now available at https://zenodo.org/record/837925

Ontogenetic dietary information of the California sea lion (\u3ci\u3eZalophus californianus\u3c/i\u3e) assessed using stable isotope analysis

We used stable carbon (δ13C) and nitrogen (δ15N) isotopes to examine ontogenetic dietary changes in 289 California sea lions (Zalophus californianus) at San Miguel Island, California during 2004–2007. Tissues analyzed included fur, red blood cells, plasma, and serum. For all tissues, pups had higher δ15N values and lower δ13C values compared to adults, which indicated that pups were feeding higher trophically than older conspecifics and on a lipid-rich milk diet prior to weaning. Yearling δ15N values were slightly lower than pup or nearly indistinguishable from adult values depending on the tissue analyzed, indicating a dietary shift from maternal dependency to independent foraging. Juveniles (2–4 yr) and adults (\u3e4 yr) had similar δ15N values indicating they fed at a similar trophic level. There did not appear to be a pronounced dietary shift in δ13C values. However, δ13C values integrated with telemetry data indicated that postweaned individuals fed in similar foraging areas. Dietary changes during early life stages may be due to differences in physiology, morphology, experience, or energetic requirements; however, young animals are able to attain the skills needed to consume adult prey types near the end of their second year of life

High VF frequencies correlate with the efficiency of immature DC viral transfer.

<p>(<b>A</b>) Schematic of the DC-CD4 T cell transfer assay. DC are infected with either HIV^WT (high VF frequency) or HIV^-NEF-ve (low VF frequency) pseudotyped with the VSVg glycoprotein, to ensure equal infection frequencies. After 4 days, DC infections are normalized to 5% with uninfected DC. Normalized populations are serially diluted below 1 infected DC per co-culture. 4 days post co-culture, CD4 T cell infections are resolved by staining cells for of HIV capsid and resolution by flow cytometry. (<b>B</b>) Flow cytometry detection of HIV p24 within CD4 T cell recipients when input infected DC are limiting (upper panel) versus (<b>C</b>) when input infected CD4 T cells are limiting (lower panel). Approximate infected cell number input into co-cultures is indicated at “Approx. Input*” on the X-axis. CD4 T cell infection frequencies are detected by the accumulation of a high HIV p24 population as indicated by the square gate in each dot-plot. Statistical difference is presented in upper HIV WT panels, and is calculated from data acquired from the same assay performed in triplicate. CD4 T cell infection frequency versus infected donor input is further summarized in right panels for two representative donors. Standard deviations represent co-cultures in triplicate. Data is representative of <i>n</i> = 8 independent donors.</p

Complementary live imaging approaches reveal abundant HIV tipped filopodia (VF) on infected DC.

<p>(<b>A</b>) Detection strategy of HIV-T. The HIV Gag polyprotein is presented in the context of the HIV open reading frames. The biarsenical fluorescent dye FlAsH is shown and binds to a 12 amino acid motif (in bold) at the C-Terminus of Matrix. The protease cleavage site between HIV Matrix and Capsid is highlighted by black scissors. (<b>B</b>) Detection strategy using HIV-iGFP. HIV-iGFP constructs encode eGFP at the C-terminus of HIV matrix and are flanked by 5′ and 3′ HIV protease cleavage sites (highlighted by black scissors). For generation of cell-free virus with comparable infectivity to WT HIV Gag and Gag-Pol are expressed in trans to the HIV iGFP genome (see bottom of panel; HIV Gag only shown) to increase viral infectivity in one round. (<b>C</b>) <b>&</b> (<b>D</b>) Rescuing infectivity of HIV-iGFP. (<b>C</b>) HIV iGFP was prepared by co-transfecting WT HIV or WT Gag and Gag -POL (psPAX2) with HIV iGFP at an equimolar ratio into the 293T cell line. Three days post transfection, supernatants were harvested, diluted 1/1000 and 200 ml was added to 1×10³ TZM-bl cells (HeLa HIV indicator cell line), seeded 24 hours prior in a 96 well plate. % infectivity is relative to wild type HIV and calculated as the (co-transfections)/(HIV-WT alone)×100. Statistical differences are presented as <i>p</i> values. Standard deviations are derived from assays in triplicate. (<b>D</b>) Further titration of psPAX2∶HIV-iGFP. As in C. HIV-iGFP was co-transfected with psPAX2, but here at as a titration. Supernatants were subsequently titered using the TZM-bl cell line as in C. Standard deviations and <i>p</i> values also as per C. % infectivity relative to wild type HIV is calculated as in C. (<b>E</b>) DC were infected with an MOI of 0.1 with either WT HIV (left panel), WT HIV rescued HIV-iGFP virus (middle panel) or psPAX2 rescued HIV-iGFP (right panel) as outlined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#s4" target="_blank">material and methods</a>. To determine total infection, infected DC were stained with anti-HIV-p24 antibody KC57-RD1. Gates in panels reflect eGFP signal from infected p24 high cells, with percentages from gates presented in the lower right corners. Note WT rescued HIV iGFP virus generates infected DC with diluted eGFP signal. (<b>F</b>) Infected DCs expressing HIV-iGFP 4 days post infection and co-cultured with autologous resting CD4 T cells at a ratio of 1 DC to 3 CD4 T cells (images are also representative for HIV-T). Filopodia are highlighted by dotted lines. Neighboring CD4 T cells that are in contact with filopodia are marked as (T) (<b>G</b>) HIV iGFP infected cells (HIV in white) have been fixed and stained for F-actin using phalloidin dye (red). Note all filopodia stained red, bear HIV at their terminal tips (All scale bars are 5 µm). (<b>H</b>) Average lengths of filopodia & VF across multiple DC donors. Infected or uninfected DCs (untreated U/T) were co-cultured with CD4 T cells as in F. Length of filopodia from the base at the plasma membrane to the tip was calculated in live infected and uninfected DC donors. VF and Filopodia lengths in infected and uninfected co-cultures from D1 & D2 are presented as a comparison. Filopodial lengths are representative of greater than <i>n</i> = 20 donors. VF and filopodia from infected and uninfected U937 cell line are also presented as a comparison.</p

VF form by a Diaph2 dependent pathway with frequency regulated by HIV Nef and not HIV Env.

<p>(<b>A</b>) To further delineate how VF pathway are formed, Wasp and Diaph2 was knockdown in the U937 cell line using shRNA. After 2 weeks of puromycin selection, resistant U937 cell lines were infected with HIV iGFP and VF lengths and trajectory velocities enumerated as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g004" target="_blank">Fig. 4</a>. <i>P</i> values are included to highlight significant differences in each variable. Protein knock-down for Wasp and Diaph2 are presented in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat.1002762.s002" target="_blank">Fig. S2E</a>. The house-keeping protein Gapdh is present below to normalize lysate loading. Data is representative of 4 independent infections using HIV iGFP. (<b>B</b>) To rule out manipulation of the Arp2/3 filopodial pathway, the U937 cell line was infected with HIV iGFP and two days post infection, infected cells were treated with the Abl/Src kinase inhibitor Dasatinib at 10 µM for 4 hours. Note, under these conditions Vaccinia actin tails do not form (data not shown). VF were then enumerated for lengths and trajectory velocities as outlined <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g003" target="_blank">Fig. 3</a>. (<b>C</b>) Accumulative single particle tracking for 1 minute of VF trajectories in scrambled controls (upper panel) versus Diaph2 knockdowns (lower panel). Note the confined trajectories in the absence of Diaph2. Diaph2 knockdown particle tracking is derived from <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat.1002762.s014" target="_blank">Video S12</a>. Scale bars are 5 µm. Data from knockdown experiments is representative of 4 independent HIV iGFP infections. (<b>D</b>) Fixed cell images of control shRNA (upper panel) and Diaph2 (lower panel) transduced cells infected with HIV iGFP. Note the significantly shorter VF lengths in Diaph2 knockdown U937 cells. Scale bars are 5 µm. Images are representative of 4 independent infections with HIV iGFP. (<b>E</b>) Attenuation of cell-cell transfer in Diaph2 knockdown U937. U937 were infected with HIV and 2 days post infection were stained for HIV p24 and enumerated by flow cytometry. After infections were verified to be equivalent, infected U937 cells were co-cultured at a ratio of 1∶5 with the T cell HIV indicator cell line JLTR-R5. Four days post infection, fluorescent images were acquired for the entire well and enumerated using Image J. Standard deviations represent co-cultures in triplicate. Data is representative of 3 independent infections. (<b>F</b>) VF form in the absence of HIV envelope. DCs were infected with either VSVg pseudotyped HIV iGFP or HIV iGFP^-ENV-ve as outlined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g001" target="_blank">Fig. 1</a>. VF were then enumerated for lengths and trajectory velocities as outlined B. Data is representative of four independent infections. <i>P</i> values are presented for significant differences. (<b>G</b>) Deletion of HIV Nef leads to significantly lower VF frequency on DC. Enumeration of VF numbers over time in uninfected DCs (U/T), or HIV infected DCS with HIV⁻iGFP or HIV^-NEF-iGFP. Each point represents live imaging of a VF bearing DC over a period of 2 minutes under imaging conditions outlined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#s4" target="_blank">materials and methods</a>. Accumulative data presented is equally drawn from 5 independent donors. Statistical significance is indicated by <i>p</i> values.</p

VF are capped and continous with immature HIV buds and do not associate with Arp2/3 antigens.

<p>(<b>A</b>) HIV envelope staining at the filopodial tip. An infected DC is presented bearing two long VF (HIV iGFP in white and Phalloidin staining in red) in excess of 20 µm (center panel boxed sections labeled 1 & 2). Left and right panels are magnified and HIV envelope stain is presented as blue. Scale bars in the center panel are 5 µm. Scale bars in left and right panels are 1 µm. (<b>B</b>)<b>–</b>(<b>D</b>) HIV at the tip of VF consists of cytosolic uncleave HIV Gag. (<b>B</b>) HIV-T FlAsH staining (white) at the tip of VF with F-actin staining using phalloidin (red) (scale bar is at 5 µm). (<b>C</b>) Further confirmation that HIV particles consist primarily of uncleaved HIV Gag. Image presented is HIV iGFP DC (all HIV particles will be detected) and counter-stained with the anti-p24/Capsid mAb 183 that specifically detects cleaved HIV p24/Capsid. Note the lack of mAb staining for HIV iGFP particles. Scale bar is at 5 µm. (<b>C</b>) Image is representative VF after imaging HIV infected DC via transmission electron microscopy (scale bar at 100 nm). Images in A-C are representative of <i>n</i> = 6 infected DC donors with HIV-T, HIV iGFP (fluorescence) or HIV (electron microscopy). (<b>E</b>) <b>&</b> (<b>F</b>) Virions unable to undergo fission from the plasma membrane (HIV GAG PTAP mutants) form VF. (<b>E</b>) A representative image of VF is presented in the fluorescent image, with HIV iGFP in white and phalloidin staining of actin in red. Note the mutation of the PTAP motif does not prevent VF formation. Data is representative of three independent infections. (<b>F</b>) DCs were infected with HIV iGFP or HIV iGFP^PTAP-ve. VF lengths and average trajectory velocities are calculated as outlined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g001" target="_blank">Fig. 1</a> & <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g002" target="_blank">2</a>. Statistical significance is presented as <i>p</i> values. Data is representative of <i>n</i> = 3 independent experiments. (<b>G</b>) <b>&</b> (<b>H</b>) VF are enriched for filopodial antigens, but their antigens do not routinely co-localize with immature HIV particles. Immature DCs were infected as outlined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat-1002762-g001" target="_blank">Fig. 1</a> and then fixed and counter stained for filopodial antigens (blue), (<b>G</b>) Arp2 and (<b>H</b>) phosphotyrosine (pTyr) staining are presented as overlays with F-actin (red) and HIV iGFP (white). HIV particles in close association with the antigenic stain are highlighted by asterix in volume projected images, whilst non-associated particles are marked by arrows. Staining for Wasp and Cortactin are presented for comparison in the supplementary <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002762#ppat.1002762.s002" target="_blank">Fig. S2</a>. All scale bars are at 5 µm. Images are representative of <i>n</i> = 7 independent donors.</p