Universal surface-enhanced Raman tags : individual nanorods for measurements from the visible to the infrared (514 – 1064 nm)

Surface-enhanced Raman scattering (SERS) is a promising imaging modality for use in a variety of multiplexed tracking and sensing applications in biological environments. However, the uniform production of SERS nanoparticle tags with high yield and brightness still remains a significant challenge. Here, we describe an approach based on the controlled co-adsorption of multiple dye species onto gold nanorods to create tags that can be detected across a much wider range of excitation wavelengths (514 – 1064 nm) compared to conventional approaches that typically focus on a single wavelength. This was achieved without the added complexity of nanoparticle aggregation or growing surrounding metallic shells to further enhance the surface-enhanced resonance Raman scattering (SERRS) signal. Correlated Raman and scanning electron microscopy mapping measurements of individual tags were used to clearly demonstrate that strong and reproducible SERRS signals at high particle yields (>92 %) were readily achievable. The polyelectrolyte-wrapped nanorod-dye conjugates were also found to be highly stable as well as non-cytotoxic. To demonstrate the use of these universal tags for the multimodal optical imaging of biological specimens, confocal Raman and fluorescence maps of stained immune cells following nanoparticle uptake were acquired at several excitation wavelengths and compared with dark-field images. The ability to colocalize and track individual optically encoded nanoparticles across a wide range of wavelengths simultaneously will enable the use of SERS alongside other imaging techniques for the real-time monitoring of cell-nanoparticle interactions

Infection of Semen-Producing Organs by SIV during the Acute and Chronic Stages of the Disease

International audienceBACKGROUND: Although indirect evidence suggests the male genital tract as a possible source of persistent HIV shedding in semen during antiretroviral therapy, this phenomenon is poorly understood due to the difficulty of sampling semen-producing organs in HIV+ asymptomatic individuals. METHODOLOGY/PRINCIPAL FINDINGS: Using a range of molecular and cell biological techniques, this study investigates SIV infection within reproductive organs of macaques during the acute and chronic stages of the disease. We demonstrate for the first time the presence of SIV in the testes, epididymides, prostate and seminal vesicles as early as 14 days post-inoculation. This infection persists throughout the chronic stage and positively correlates with blood viremia. The prostate and seminal vesicles appear to be the most efficiently infected reproductive organs, followed by the epididymides and testes. Within the male genital tract, mostly T lymphocytes and a small number of germ cells harbour SIV antigens and RNA. In contrast to the other organs studied, the testis does not display an immune response to the infection. Testosteronemia is transiently increased during the early phase of the infection but spermatogenesis remains unaffected. CONCLUSIONS/SIGNIFICANCE: The present study reveals that SIV infection of the macaque male genital tract is an early event and that semen-producing organs display differential infection levels and immune responses. These results help elucidate the origin of HIV in semen and constitute an essential base to improving the design of antiretroviral therapies to eradicate virus from semen

Dire i traumi dell’Italia del Novecento. Dall’esperienza alla creazione letteraria e artistica

Recensione a cura di Maria Pappa https://www.spiweb.it/cultura-e-societa/dire-traumi-dellitalia-del-novecento-cura-di-m-p-de-paulis-v-agostini-ouafi-s-amrani-b-le-gouez-recensione-di-m-pappa/ International audienceIl volume invita a una riflessione teorica ed esemplificativa sulla natura e sulle caratteristiche dei maggiori traumi, individuali e collettivi, che hanno segnato la storia italiana del Novecento: la Grande Guerra, il Fascismo, la Seconda guerra mondiale, i campi di concentramento e di sterminio. Tali traumi vengono qui studiati nelle forme testimoniali, narrative e artistiche in cui sono stati non detti o messi in scena, raccontati oralmente o per iscritto, rappresentati cinematograficamente oppure dipinti e variamente rappresentati nelle arti visive dalla cultura italiana del Novecento. Questi traumi, contestualizzati dai vari studiosi rispetto alle violente e dolorose esperienze che li hanno provocati, sono stati colti e descritti, sia nella fase immediata in cui lo shock psicologico e il trauma fisico sono stati subìti dal soggetto narrante, sia nel processo di superamento e rielaborazione di essi da parte del testimone tramite il suo taumaturgico racconto.È stato quindi collettivamente assunto come presupposto critico di partenza l’interrogativo seguente: in che modo e in quale misura la creazione letteraria e artistica dell’Italia contemporanea può essere interpretata come riscrittura immediata o rielaborazione retrospettiva dei maggiori traumi del secolo? Tale interrogativo consente di tracciare un preciso e pertinente percorso del Novecento italiano in cui il trauma individuale, sempre strettamente connesso ai fatti storici, ha prodotto una letteratura e un’arte contraddistinte dall’impegno etico che è parte integrante di un progetto di più ampia portata: consegnare gli insegnamenti del passato alla posterità, “a futura memoria”

House dust mite allergen activates human eosinophils via formyl peptide receptor and formyl peptide receptor-like 1.

International audienceThe objective was to evaluate which receptors house dust mite (HDM) and birch pollen extracts engage to activate human eosinophils. Chemotaxis and degranulation were studied in eosinophils pretreated with pertussis toxin and other antagonists of G protein-coupled receptors, e.g. the formyl peptide receptor (FPR), CC chemokine receptor 3 (CCR3) and leukotriene receptor B4 (LTB(4)R). Inhibition of the FPR as well as desensitization of the receptor rendered eosinophils anergic to activation by the allergens. Blockade of CCR3 or LTB(4)R did not affect eosinophilic reactivity. It was determined by PCR that human eosinophils express the FPR family members FPR and FPR-like 1 (FPRL1). HDM, unlike birch pollen, evoked calcium fluxes in HL-60 cells transfected with FPR or FPRL1. Although both allergens gave rise to calcium transients in neutrophils, which also express FPR and FPRL1, only the HDM response was decreased by the FPR antagonist. Moreover, neutrophils migrated toward HDM but not to birch pollen. Eosinophils pretreated with inhibitors of MAPK p38, ERK1/2 or protein kinase C exhibited diminished responsiveness to the aeroallergens. This study indicates that FPR and FPRL1 mediate the activation of eosinophils by HDM, whereas birch pollen employs other pathways shared with FPR to activate human eosinophils