ABSTRACT
West-Central Africa is an epicenter of the HIV pandemic; endemic to Cameroon are HIV-1 viruses belonging to all (sub)subtypes and numerous Circulating Recombinant Forms (CRFs). The rural villages of Cameroon harbor many strains of HIV-1, though these areas are not as well monitored as the urban centers. In the present study, 82 specimens obtained in 2000 and 2001 from subjects living in the rural villages of the South and West Regions of Cameroon were subtyped in gag, pol, and env and compared to 90 specimens obtained in 2006-2008 in the same regions, in order to analyze HIV-1 evolution in these rural areas. It was found that in the South Region, the proportion of unique recombinant forms (URFs) remained constant (~40%), while the amount of URFs containing fragments of a CRF increased by 25%. (Sub)subtypes A1, F2, H, and K, and CRF09_cpx, identified in 2000 and 2001, were replaced by CRFs 01_AE, 13_cpx, 14_BG, and 18_cpx in 2006-2008. In the West Region, (sub)subtypes A2, C, G, and H, and CRFs 01_AE and 09_cpx, identified in 2000-2001, were replaced by sub-subtype A1 and CRFs 25_cpx and 37_cpx in 2006-2008. The proportion of URFs in the West Region dropped significantly over the time period by 43%. In both Regions, the proportion of CRF02_AG increased at all loci. These findings demonstrate that the evolution of HIV-1 is distinct for each endemic region, and suggests that the proportion of URFs containing CRF fragments is increasing as the genetic identity of the virus continues to shift dramatically. This highlights the concern that subtype-specific vaccines may not be relevant in Cameroon, and that the distribution of viral diversity in these regions of Cameroon must be carefully monitored.
ABSTRACT
Phosphorylation of the NR1 subunit of NMDA receptors (NMDARs) at serine (S) 897 is markedly reduced in schizophrenia patients. However, the role of NR1 S897 phosphorylation in normal synaptic function and adaptive behaviors are unknown. To address these questions, we generated mice in which the NR1 S897 is replaced with alanine (A). This knock-in mutation causes severe impairment in NMDAR synaptic incorporation and NMDAR-mediated synaptic transmission. Furthermore, the phosphomutant animals have reduced AMPA receptor (AMPAR)-mediated synaptic transmission, decreased AMPAR GluR1 subunit in the synapse, and impaired long-term potentiation. Finally, the mutant mice exhibit behavioral deficits in social interaction and sensorimotor gating. Our results suggest that an impairment in NR1 phosphorylation leads to glutamatergic hypofunction that can contribute to behavioral deficits associated with psychiatric disorders.
Subject(s)
Behavior, Animal/physiology , Neuronal Plasticity , Receptors, N-Methyl-D-Aspartate/genetics , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Brain/physiology , Brain/ultrastructure , Gene Knock-In Techniques , In Vitro Techniques , Long-Term Potentiation/genetics , Long-Term Potentiation/physiology , Male , Mice , Mice, Inbred C57BL , Mutation, Missense , Neuronal Plasticity/genetics , Neurons/physiology , Neurons/ultrastructure , Phosphorylation , Receptors, AMPA/metabolism , Schizophrenia/genetics , Social Behavior , Synapses/genetics , Synapses/physiology , Synapses/ultrastructure , Synaptic Transmission/genetics , Synaptic Transmission/physiologyABSTRACT
Transmissible spongiform encephalopathies (TSEs), also termed prion diseases, are fatal neurodegenerative conditions that affect both humans and animals. The transmissibility and fatal nature of TSEs necessitate their rapid and accurate diagnosis. Laser-induced fluorescence (LIF) spectrofluorometry is useful for obtaining measurements on fluorescence-labeled targets with a high degree of sensitivity. In the present study, we applied this technology to the immunological detection of abnormal prion protein, PrPSc, which is a universal diagnostic marker for TSEs. The assay format consists of a magnetic bead-based sandwich immunoassay utilizing a biotin-conjugated capture antibody and a fluorophore-labeled detector antibody. By using one pair of anti-PrP monoclonal antibodies (MAbs), PrPSc in brain homogenates from various experimental and natural TSEs can be easily detected with high specificity. Furthermore, the assay proved to be applicable for the detection of PrPSc in the lymph nodes from deer with TSE. The sensitivity of the assay was shown to be comparable to standard immunoblotting, but has several advantages over conventional tests, in terms of flexibility, simplicity, specificity, and run time. These results provide an important basis for the development of an early diagnostic test with potential for multi-sample analysis.
