Intra- and interspecies interactions between prion proteins and effects of mutations and polymorphisms

Recently, crystallization of the prion protein in a dimeric form was reported. Here we show that native soluble homogenous FLAG-tagged prion proteins from hamster, man and cattle expressed in the baculovirus system are predominantly dimeric. The PrP/PrP interaction was confirmed in Semliki Forest virus-RNA transfected BHK cells co-expressing FLAG- and oligohistidine-tagged human PrP. The yeast two-hybrid system identified the octarepeat region and the C-terminal structured domain (aa90-aa230) of PrP as PrP/PrP interaction domains. Additional octarepeats identified in patients suffering from fCJD reduced (wtPrP versus PrP+90R) and completely abolished (PrP+90R versus PrP+90R) the PrP/PrP interaction in the yeast two-hybrid system. In contrast, the Met/Val polymorphism (aa129), the GSS mutation Pro102Leu and the FFI mutation Asp178Asn did not affect PrP/PrP interactions. Proof of interactions between human or sheep and bovine PrP, and sheep and human PrP, as well as lack of interactions between human or bovine PrP and hamster PrP suggest that interspecies PrP interaction studies in the yeast two-hybrid system may serve as a rapid pre-assay to investigate species barriers in prion diseases

Inoculation route-dependent Lassa virus dissemination and shedding dynamics in the natural reservoir – Mastomys natalensis

Lassa virus (LASV), a Risk Group-4 zoonotic haemorrhagic fever virus, affects sub-Saharan African countries. Lassa fever, caused by LASV, results in thousands of annual deaths. Although decades have elapsed since the identification of the Natal multimammate mouse (Mastomys natalensis) as a natural reservoir of LASV, little effort has been made to characterize LASV infection in its reservoir. The natural route of infection and transmission of LASV within M. natalensis remains unknown, and the clinical impact of LASV in M. natalensis is mostly undescribed. Herein, using an outbred colony of M. natalensis, we investigate the replication and dissemination dynamics of LASV in this reservoir following various inoculation routes. Inoculation with LASV, regardless of route, resulted in a systemic infection and accumulation of abundant LASV-RNA in many tissues. LASV infection in the Natal multimammate mice was subclinical, however, clinical chemistry values were transiently altered and immune infiltrates were observed histologically in lungs, spleens and livers, indicating a minor disease with coordinated immune responses are elicited, controlling infection. Intranasal infection resulted in unique virus tissue dissemination dynamics and heightened LASV shedding, compared to subcutaneous inoculation. Our study provides important insights into LASV infection in its natural reservoir using a contemporary infection system, demonstrating that specific inoculation routes result in disparate dissemination outcomes, suggesting intranasal inoculation is important in the maintenance of LASV in the natural reservoir, and emphasizes that selection of the appropriate inoculation route is necessary to examine aspects of viral replication, transmission and responses to zoonotic viruses in their natural reservoirs.Peer Reviewe

Meson Decay Constants from Isospin Mass Splittings in the Quark Model

Decay constants of $D$ and $B$ mesons are estimated within the framework of a heavy-quark approach using measured isospin mass splittings in the $D$, $D^*$, and $B$ states to isolate the electromagnetic hyperfine interaction between quarks. The values $f_D = (262 \pm 29)$ MeV and $f_B = (160 \pm 17)$ MeV are obtained. Only experimental errors are given; possible theoretical ambiguities, and suggestions for reducing them, are noted.Comment: 7 pages, LaTeX, EFI-92-3

Evidence of beta amyloid independent small vessel disease in familial Alzheimer\u27s disease

\ua9 2022 The Authors. Brain Pathology published by John Wiley & Sons Ltd on behalf of International Society of Neuropathology. We studied small vessel disease (SVD) pathology in Familial Alzheimer\u27s disease (FAD) subjects carrying the presenilin 1 (PSEN1) p.Glu280Ala mutation in comparison to those with sporadic Alzheimer\u27s disease (SAD) as a positive control for Alzheimer\u27s pathology and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) bearing different NOTCH3 mutations, as positive controls for SVD pathology. Upon magnetic resonance imaging (MRI) in life, some FAD showed mild white matter hyperintensities and no further radiologic evidence of SVD. In post-mortem studies, total SVD pathology in cortical areas and basal ganglia was similar in PSEN1 FAD and CADASIL subjects, except for the feature of arteriosclerosis which was higher in CADASIL subjects than in PSEN1 FAD subjects. Further only a few SAD subjects showed a similar degree of SVD pathology as observed in CADASIL. Furthermore, we found significantly enlarged perivascular spaces in vessels devoid of cerebral amyloid angiopathy in FAD compared with SAD and CADASIL subjects. As expected, there was greater fibrinogen-positive perivascular reactivity in CADASIL but similar reactivity in PSEN1 FAD and SAD groups. Fibrinogen immunoreactivity correlated with onset age in the PSEN1 FAD cases, suggesting increased vascular permeability may contribute to cognitive decline. Additionally, we found reduced perivascular expression of PDGFRβ AQP4 in microvessels with enlarged PVS in PSEN1 FAD cases. We demonstrate that there is Aβ-independent SVD pathology in PSEN1 FAD, that was marginally lower than that in CADASIL subjects although not evident by MRI. These observations suggest presence of covert SVD even in PSEN1, contributing to disease progression. As is the case in SAD, these consequences may be preventable by early recognition and actively controlling vascular disease risk, even in familial forms of dementia

Anti-PrP antibodies block PrPSc replication in prion-infected cell cultures by accelerating PrPC degradation.

manuscript received October 15, 2003; revised manuscript received December 15, 2003; accepted December 16, 2003. We thanks P. Rondard, O Bischof, J.-L. Laplanche and J.-P. Pin for their fruitful discussions. we are grateful to S. barrère for her assistance in the statistical analysis of the data and H. McMahon for her assistance in reading the manuscript

Upsilonium polarization as a touchstone in understanding the proton dynamics in QCD

In the framework of the k_t-factorization approach, the production of $\Upsilon mesons at the Fermilab Tevatron and CERN LHC is considered, and the predictions on the spin alignment parameter$\alpha$ are presented. We argue that measuring the polarization of quarkonium states can serve as a crucial test discriminating two competing theoretical approaches to parton dynamics in QCD.Comment: 8 pages, 2 figure

Measurement of the leptonic decay widths of the phi-meson with the KLOE detector

The phi-meson leptonic widths, Gee and Gmm, are obtained, respectively, from the e+e- forward-backward asymmetry and the muon cross section around the phi-mass energy. We find Gee=1.32⊕0.05⊕0.03 kev and sqrt(GeeGmm)= 1.320⊕0.018⊕0.017 kev. These results, compatible with Gee=Gmm, provide a precise test of lepton universality. Combining the two results gives G_lept=1.320⊕0.023 kev.Comment: 10 pages and 8 figures to be submitted to Phys.Lett.

Deep inelastic J/ψJ/\psi production at HERA in the kTk_T-factorization approach and its consequences for the nonrelativistic QCD

In the framework of the $k_T$-factorization approach, we analyse the inclusive and inelastic production of $J/\psi$ particles in deep inelastic $ep$ scattering. We take into account both colour-singlet and colour-octet production channels. We inspect the sensitivity of theoretical predictions to the choice of model parameters. Our theoretical results agree reasonably well with recent experimental data collected by the collaboration H1 at HERA.Comment: 14 pages, 6 figure