A dynamic deep sleep stage in Drosophila

Howmight one determine whether simple animals such as flies sleep in stages? Sleep inmammalsis a dynamic process involving different stages of sleep intensity, and these are typically associated with measurable changes in brain activity (Blake and Gerard, 1937; Rechtschaffen and Kales, 1968; Webb and Agnew, 1971). Evidence for different sleep stages in invertebrates remains elusive, even though it has been well established that many invertebrate species require sleep (Campbell and Tobler, 1984; Hendricks et al., 2000; Shaw et al., 2000; Sauer et al., 2003). Here we used electrophysiology and arousal-testing paradigms to show that the fruit fly, Drosophila melanogaster, transitions between deeper and lighter sleep within extended bouts of inactivity, with deeper sleep intensities after15 and30 min of inactivity. As in mammals, the timing and intensity of these dynamic sleep processes in flies is homeostatically regulated and modulated by behavioral experience. Two molecules linked to synaptic plasticity regulate the intensity of the first deep sleep stage. Optogenetic upregulation of cyclic adenosine monophosphate during the day increases sleep intensity at night, whereas loss of function of a molecule involved in synaptic pruning, the fragile-X mental retardation protein, increases sleep intensity during the day. Our results show that sleep is not homogenous in insects, and suggest that waking behavior and the associated synaptic plasticity mechanisms determine the timing and intensity of deep sleep stages in Drosophila

Novel Escape Mutants Suggest an Extensive TRIM5α Binding Site Spanning the Entire Outer Surface of the Murine Leukemia Virus Capsid Protein

After entry into target cells, retroviruses encounter the host restriction factors such as Fv1 and TRIM5α. While it is clear that these factors target retrovirus capsid proteins (CA), recognition remains poorly defined in the absence of structural information. To better understand the binding interaction between TRIM5α and CA, we selected a panel of novel N-tropic murine leukaemia virus (N-MLV) escape mutants by a serial passage of replication competent N-MLV in rhesus macaque TRIM5α (rhTRIM5α)-positive cells using a small percentage of unrestricted cells to allow multiple rounds of virus replication. The newly identified mutations, many of which involve changes in charge, are distributed over the outer ‘top’ surface of N-MLV CA, including the N-terminal β-hairpin, and map up to 29 Ao apart. Biological characterisation with a number of restriction factors revealed that only one of the new mutations affects restriction by human TRIM5α, indicating significant differences in the binding interaction between N-MLV and the two TRIM5αs, whereas three of the mutations result in dual sensitivity to Fv1n and Fv1b. Structural studies of two mutants show that no major changes in the overall CA conformation are associated with escape from restriction. We conclude that interactions involving much, if not all, of the surface of CA are vital for TRIM5α binding

A systematic review of different models of home and community care services for older persons

<p>Abstract</p> <p>Background</p> <p>Costs and consumer preference have led to a shift from the long-term institutional care of aged older people to home and community based care. The aim of this review is to evaluate the outcomes of case managed, integrated or consumer directed home and community care services for older persons, including those with dementia.</p> <p>Methods</p> <p>A systematic review was conducted of non-medical home and community care services for frail older persons. MEDLINE, PsycINFO, CINAHL, AgeLine, Scopus and PubMed were searched from 1994 to May 2009. Two researchers independently reviewed search results.</p> <p>Results</p> <p>Thirty five papers were included in this review. Evidence from randomized controlled trials showed that case management improves function and appropriate use of medications, increases use of community services and reduces nursing home admission. Evidence, mostly from non-randomized trials, showed that integrated care increases service use; randomized trials reported that integrated care does not improve clinical outcomes. The lowest quality evidence was for consumer directed care which appears to increase satisfaction with care and community service use but has little effect on clinical outcomes. Studies were heterogeneous in methodology and results were not consistent.</p> <p>Conclusions</p> <p>The outcomes of each model of care differ and correspond to the model's focus. Combining key elements of all three models may maximize outcomes.</p

Trim-Cyclophilin A Fusion Proteins Can Restrict Human Immunodeficiency Virus Type 1 Infection at Two Distinct Phases in the Viral Life Cycle

The Trim5α protein from several primates restricts retroviruses in a capsid (CA)-dependent manner. In owl monkeys, the B30.2 domain of Trim5 has been replaced by cyclophilin A (CypA) following a retrotransposition. Restriction of human immunodeficiency virus type 1 (HIV-1) by the resulting Trim5-CypA fusion protein depends on CA binding to CypA, suggesting both that the B30.2 domain might be involved in CA binding and that the tripartite RING motif, B-BOX, and coiled coil (RBCC) motif domain can function independently of the B30.2 domain in restriction. To investigate the potential of RBCCs from other Trims to participate in restricting HIV-1, CypA was fused to the RBCC of Trim1, Trim18, and Trim19 and tested for restriction. Despite low identity within the RBCC domain, all fusion proteins were found to restrict HIV-1 but not the nonbinding G89V mutant, indicating that the overall structure of RBCC and not its primary sequence was important for the restriction function. The critical interaction between CA and Trim-CypA appears to take place soon after viral entry. Quantitative PCR analysis of viral reverse transcriptase products revealed that the different fusion proteins block HIV-1 at two distinct stages of its life cycle, either prior to reverse transcription or just before integration. With Trim1 and Trim18, this timing is dependent on the length of the Trim component of the fusion protein. These observations suggest that restriction factor binding can have different mechanistic consequences

Duplication and divergence of the retrovirus restriction gene Fv1 in Mus caroli allows protection from multiple retroviruses

International audienceViruses and their hosts are locked in an evolutionary race where resistance to infection is acquired by the hosts while viruses develop strategies to circumvent these host defenses. Forming one arm of the host defense armory are cell autonomous restriction factors like Fv1. Originally described as protecting laboratory mice from infection by murine leukemia virus (MLV), Fv1s from some wild mice have also been found to restrict non-MLV retroviruses, suggesting an important role in the protection against viruses in nature. We surveyed the Fv1 genes of wild mice trapped in Thailand and characterized their restriction activities against a panel of retroviruses. An extra copy of the Fv1 gene, named Fv7, was found on chromosome 6 of three closely related Asian species of mice: Mus caroli, M. cervicolor, and M. cookii. The presence of flanking repeats suggested it arose by LINE-mediated retroduplication within their most recent common ancestor. A high degree of natural variation was observed in both Fv1 and Fv7 and, on top of positive selection at certain residues, insertions and deletions were present that changed the length of the reading frames. These genes exhibited a range of restriction phenotypes, with activities directed against gamma-, spuma-, and lentiviruses. It seems likely, at least in the case of M. caroli, that the observed gene duplication may expand the breadth of restriction beyond the capacity of Fv1 alone and that one or more such viruses have recently driven or continue to drive the evolution of the Fv1 and Fv7 genes

All Three Variable Regions of the TRIM5α B30.2 Domain Can Contribute to the Specificity of Retrovirus Restriction

Recent studies have revealed the contribution of TRIM5α to retrovirus restriction in cells from a variety of primate species. TRIM5α consists of a tripartite motif (the RBCC domain) followed by a B30.2 domain. The B30.2 domain is thought to be involved in determination of restriction specificity and contains three variable regions. To investigate the relationship between the phylogeny of primate TRIM5α and retrovirus restriction specificity, a series of chimeric TRIM5α consisting of the human RBCC domain followed by the B30.2 domain from various primates was constructed. These constructs showed restriction profiles largely consistent with the origin of the B30.2 domain. Restriction specificity was further investigated with a variety of TRIM5αs containing mixed or mutated B30.2 domains. This study revealed the importance of all three variable regions for determining restriction specificity. Based on the molecular structures of other PRYSPRY domains solved recently, a model for the molecular structure of the B30.2 domain of TRIM5α was developed. The model revealed that the variable regions of the B30.2 domain are present as loops located on one side of the B30.2 core structure. It is hypothesized that these three loops form a binding surface for virus and that evolutionary changes in any one of the loops can alter restriction specificity

Capsid Processing Requirements for Abrogation of Fv1 and Ref1 Restriction

Murine leukemia virus is restricted in mouse cells lines by a host factor known as Fv1 and in human cell lines by Ref1. Genetic evidence indicates that these restriction factors target the virus capsid (CA) protein. Restriction can be overcome by adding virus at a high multiplicity of infection, indicating that the restriction factors can be saturated. Cells preexposed to restricted virus will allow infection by a second virus which would normally be restricted. This phenomenon is known as abrogation; it provides us with a tool with which to study the interaction of virus with restriction factors. We tested the abilities of several Gag processing mutants to abrogate restriction. Our results show that CA must be cleaved from both p12 and nucleocapsid in order for the incoming virion to interact with the restriction factor. Endogenous expression of properly processed CA, however, failed to abrogate restriction. These results suggest that as well as being processed, CA must also be properly assembled in the form of a condensed viral core in order to interact with Fv1 and Ref1. This polymeric structure may contain restriction factor binding sites not present in monomeric CA