Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species

BACKGROUND: D-type simian retrovirus-2 (SRV-2) causes an AIDS-like immune deficiency syndrome (SAIDS) in various macaque species. SAIDS is often accompanied by retroperitoneal fibromatosis (RF), an aggressive fibroproliferative disorder reminiscent of Kaposi's sarcoma in patients with HIV-induced AIDS. In order to determine the association of SRV-2 subtypes with SAIDS-RF, and study the evolution and transmission of SRV-2 in captive macaque populations, we have molecularly characterized the env gene of a number of SRV-2 isolates from different macaque species with and without RF. RESULTS: We sequenced the env gene from eighteen SRV-2 isolates and performed sequence comparisons and phylogenetic analyses. Our studies revealed the presence of six distinct subtypes of SRV-2, three of which were associated with SAIDS-RF cases. We found no association between SRV-2 subtypes and a particular macaque species. Little sequence variation was detected in SRV-2 isolates from the same individual, even after many years of infection, or from macaques housed together or related by descent from a common infected parent. Seventy-two amino acid changes were identified, most occurring in the larger gp70 surface protein subunit. In contrast to the lentiviruses, none of the amino acid variations involved potential N-linked glycosylation sites. Structural analysis of a domain within the gp22/gp20 transmembrane subunit that was 100% conserved between SRV-2 subtypes, revealed strong similarities to a disulfide-bonded loop that is crucial for virus-cell fusion and is found in retroviruses and filoviruses. CONCLUSION: Our study suggests that separate introductions of at least six parental SRV-2 subtypes into the captive macaque populations in the U.S. have occurred with subsequent horizontal transfer between macaque species and primate centers. No specific association of a single SRV-2 subtype with SAIDS-RF was seen. The minimal genetic variability of the env gene within a subtype over time suggests that a strong degree of adaptation to its primate host has occurred during evolution of the virus

Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species

Abstract Background D-type simian retrovirus-2 (SRV-2) causes an AIDS-like immune deficiency syndrome (SAIDS) in various macaque species. SAIDS is often accompanied by retroperitoneal fibromatosis (RF), an aggressive fibroproliferative disorder reminiscent of Kaposi's sarcoma in patients with HIV-induced AIDS. In order to determine the association of SRV-2 subtypes with SAIDS-RF, and study the evolution and transmission of SRV-2 in captive macaque populations, we have molecularly characterized the env gene of a number of SRV-2 isolates from different macaque species with and without RF. Results We sequenced the env gene from eighteen SRV-2 isolates and performed sequence comparisons and phylogenetic analyses. Our studies revealed the presence of six distinct subtypes of SRV-2, three of which were associated with SAIDS-RF cases. We found no association between SRV-2 subtypes and a particular macaque species. Little sequence variation was detected in SRV-2 isolates from the same individual, even after many years of infection, or from macaques housed together or related by descent from a common infected parent. Seventy-two amino acid changes were identified, most occurring in the larger gp70 surface protein subunit. In contrast to the lentiviruses, none of the amino acid variations involved potential N-linked glycosylation sites. Structural analysis of a domain within the gp22/gp20 transmembrane subunit that was 100% conserved between SRV-2 subtypes, revealed strong similarities to a disulfide-bonded loop that is crucial for virus-cell fusion and is found in retroviruses and filoviruses. Conclusion Our study suggests that separate introductions of at least six parental SRV-2 subtypes into the captive macaque populations in the U.S. have occurred with subsequent horizontal transfer between macaque species and primate centers. No specific association of a single SRV-2 subtype with SAIDS-RF was seen. The minimal genetic variability of the env gene within a subtype over time suggests that a strong degree of adaptation to its primate host has occurred during evolution of the virus.</p

Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species-3

<p><b>Copyright information:</b></p><p>Taken from "Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species"</p><p>Virology Journal 2006;3():11-11.</p><p>Published online 6 Mar 2006</p><p>PMCID:PMC1450265.</p><p>Copyright © 2006 Philipp-Staheli et al; licensee BioMed Central Ltd.</p>V-2 which was identical in all SRV-2 isolates and SRV-1 and SRV-3 prototypes (aa426-471) was predicted to have structural similarities to a disulfide-bonded loop presumed to be important for virus-cell fusion in a number of RNA viruses and retroviruses, including Ebola virus 1: 1EBO_A (Gp2); Ebola virus 2: 2EBO_A (Gp2); MMLV (Moloney murine leukemia virus): 1MOF (coat protein); HTLV-1 (human T-lymphotropic virus): 1MG1_A (gp21) (see text). The disulfide bridge is indicated by S-S

Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species-1

<p><b>Copyright information:</b></p><p>Taken from "Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species"</p><p>Virology Journal 2006;3():11-11.</p><p>Published online 6 Mar 2006</p><p>PMCID:PMC1450265.</p><p>Copyright © 2006 Philipp-Staheli et al; licensee BioMed Central Ltd.</p>), SRV-2D (F90346), SRV-2E (A94040), SRV-2F (SRV_sing31.2). The sequences of SRV-1 and SRV-3 were included for comparison. Dots represent amino acids identical to the reference sequence of the SRV-2A prototype. Conserved cysteine residues are shaded in yellow, while putative N-linked glycosylation sites (NXT/S) are shaded in black. The putative signal peptide, known T- and B-cell epitopes, heptad repeat, as well as the gp20 fusion and transmembrane domains are indicated and referenced in the text. A predicted disulfide linkage within the immunosuppressive peptide, and the proteolytic cleaveage sites generating the gp70 surface and gp20 transmembrane subunits are indicated. While B- and T-cell epitopes have been determined for SRV-2, the functions and locations of other domains are derived from studies in SRV-3

Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species-0

<p><b>Copyright information:</b></p><p>Taken from "Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species"</p><p>Virology Journal 2006;3():11-11.</p><p>Published online 6 Mar 2006</p><p>PMCID:PMC1450265.</p><p>Copyright © 2006 Philipp-Staheli et al; licensee BioMed Central Ltd.</p>ustalW multiple alignment using the protein maximum-likelihood method as implemented in the Phylip package (v. 3.62). The sequence of the distantly related simian sarcoma virus (SSV) protein was used as outgroup [Genbank:]. (B) A detailed phylogenetic tree of the SRV-2 reference and isolate sequences was similarly generated using SRV-3 as outgroup. Emerging clusters were labelled as subtypes SRV-2A through 2F and virus isolates from animals diagnosed with RF are indicated

Properties of poly(urea-formaldheyde) microcapsules containing an epoxy resin

Physical properties of urea-formaldehyde microcapsules containing an epoxy resin are presented and discussed. Microcapsules were prepared by in situ polymerization of monomers in an oil-in-water emulsion. Differential scanning calorimetry, thermogravimetric analysis, and scanning electronic microscopy were applied to investigate thermal and morphological microcapsule properties. Microencapsulation was detected by means of FTIR and Raman techniques. It was found that the amount of encapsulated epoxy resin as well as the extent of urea-formaldehyde polymerization depends on the reaction temperature and the stirring speed