RESUMO
This study was conducted in order to evaluate the transmission of caprine lentivirus to sheep using different experimental groups. The first one (colostrum group) was formed by nine lambs receiving colostrum from goats positive for small ruminant lentiviruses (SRLV). The second group (milk group) was established by nine lambs that received milk of these goats. Third was a control group, consisting of lambs that suckled colostrum and milk of negative mothers. Another experimental group (contact group) was formed by eight adult sheep, confined with two naturally infected goats. The groups were monitored by immunoblotting (IB), enzyme-linked immunosorbent assay (ELISA), agar gel immunodiffusion (AGID) and nested polymerase chain reaction (nPCR). All lambs that suckled colostrum and milk of infected goats and six sheep of the contact group had positive results in the nPCR, although seroconversion was detected only in three of the exposed animals, with no clinical lentiviruses manifestation, in 720 days of observation. There was a close relationship between viral sequences obtained from infected animals and the prototype CAEV-Cork. Thus, it was concluded that SRLV can be transmitted from goats to sheep, however, the degree of adaptation of the virus strain to the host species probably interferes with the infection persistence and seroconversion rate.
Assuntos
Vírus da Artrite-Encefalite Caprina/patogenicidade , Colostro/virologia , Doenças das Cabras/transmissão , Infecções por Lentivirus/transmissão , Doenças dos Ovinos/transmissão , Vírus Visna-Maedi/patogenicidade , Animais , Anticorpos Antivirais/sangue , Doenças das Cabras/virologia , Cabras/virologia , Interações Hospedeiro-Patógeno/fisiologia , Infecções por Lentivirus/virologia , Ruminantes/virologia , Soroconversão/fisiologia , Ovinos/virologia , Doenças dos Ovinos/virologiaRESUMO
HIV-1 provirus activation is under control of the long terminal repeat (LTR)-5' viral promoter region, which presents remarkable genetic variation among HIV-1 subtypes. It is possible that molecular features of the LTR contribute to the unusual profile of the subtype C epidemic in the Brazilian Southern region. To characterize the LTR of Brazilian HIV isolates, we analyzed sequences from 21 infected individuals from Porto Alegre and Salvador cities. Sequences were compared with subtype B and C reference strains from different countries. Phylogenetic analysis showed that 17 (81%) samples were subtype B and four (19%) were subtype C. Common patterns of transcription factor binding sites (TFBS) in subtypes B and C sequences were confirmed and other potential TFBS specific for subtype C were found. Brazilian subtype C sequences contained an additional NF-κB biding site, as previously described for the majority of subtype C isolates. The high level of LTR polymorphisms identified in this study might be important for viral fitness.
Assuntos
Infecções por HIV/virologia , Repetição Terminal Longa de HIV/genética , HIV-1/genética , Sequência de Bases , Brasil/epidemiologia , DNA Viral/genética , Infecções por HIV/epidemiologia , Humanos , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Alinhamento de SequênciaRESUMO
This study was conducted in order to evaluate the transmission of caprine lentivirus to sheep using different experimental groups. The first one (colostrum group) was formed by nine lambs receiving colostrum from goats positive for small ruminant lentiviruses (SRLV). The second group (milk group) was established by nine lambs that received milk of these goats. Third was a control group, consisting of lambs that suckled colostrum and milk of negative mothers. Another experimental group (contact group) was formed by eight adult sheep, confined with two naturally infected goats. The groups were monitored by immunoblotting (IB), enzyme-linked immunosorbent assay (ELISA), agar gel immunodiffusion (AGID) and nested polymerase chain reaction (nPCR). All lambs that suckled colostrum and milk of infected goats and six sheep of the contact group had positive results in the nPCR, although seroconversion was detected only in three of the exposed animals, with no clinical lentiviruses manifestation, in 720 days of observation. There was a close relationship between viral sequences obtained from infected animals and the prototype CAEV-Cork. Thus, it was concluded that SRLV can be transmitted from goats to sheep, however, the degree of adaptation of the virus strain to the host species probably interferes with the infection persistence and seroconversion rate.
.Assuntos
Animais , Vírus da Artrite-Encefalite Caprina/patogenicidade , Colostro/virologia , Doenças das Cabras/transmissão , Infecções por Lentivirus/transmissão , Doenças dos Ovinos/transmissão , Vírus Visna-Maedi/patogenicidade , Anticorpos Antivirais/sangue , Doenças das Cabras/virologia , Cabras/virologia , Interações Hospedeiro-Patógeno/fisiologia , Infecções por Lentivirus/virologia , Ruminantes/virologia , Soroconversão/fisiologia , Doenças dos Ovinos/virologia , Ovinos/virologiaRESUMO
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) control gonadal function in mammalian and many non-mammalian vertebrates through the interaction with their receptors, FSHR and LHR. Although the same is true for some reptilian species, in Squamata (lizards and snakes) there is no definitive evidence for the presence of either two distinct gonadotropins or two distinct gonadotropin receptors. Our aim was to characterize the gonadotropin receptor(s) of the Bothrops jararaca snake. Using a cDNA library from snake testis and amplification of the 5'-cDNA ending, we cloned a cDNA related to FSHR. Attempts to clone a cDNA more closely related to LHR were unsuccessful. Expression of FSHR mRNA was restricted to gonadal tissues. The snake FSHR is a G protein-coupled receptor with 673 amino acids, and the aminoterminal domain with 346 amino acids consists of a nine leucine-rich repeat-containing subdomain (LRR) flanked by two cysteine-rich subdomains. The beta-strands in the LRR are conserved with exception of the third, a region that may be important for FSH binding. In contrast with mammalian, avian and amphibian FSHRs, the snake FSHR presents amino acid deletions in the carboxyterminal region of the extracellular domain which are also seen in fish and lizard FSHRs. cAMP assays with the recombinant protein transiently expressed in HEK-293 cells showed that the snake FSHR is more sensitive to human FSH (hFSH) than to human chorionic gonadotropin. Phylogenetic analysis indicated that the squamate FSHRs group separately from mammalian FSHRs. Our data are consistent with the apparently unique gonadotropin-receptor system in Squamata reptilian subgroup. Knowledge about the snake FSHR structure may help identify structural determinants for receptor function.
Assuntos
Bothrops/genética , Clonagem Molecular , Expressão Gênica , Receptores do FSH/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , AMP Cíclico/biossíntese , DNA Complementar/química , DNA Complementar/genética , Feminino , Biblioteca Gênica , Masculino , Dados de Sequência Molecular , Filogenia , RNA Mensageiro/análise , Receptores do FSH/química , Receptores do LH/genética , Proteínas Recombinantes , Análise de Sequência , Testículo/química , TransfecçãoRESUMO
A karyotype analysis of the electric eel, Electrophorus electricus (Teleostei, Gymnotiformes), a strongly electric fish from northern South America, is presented. Two female specimens were analyzed, one from the Amazon River and one from the Araguaia River. The specimens had a chromosomal number of 2n = 52 (42M-SM + 10A). C-bands were present in a centromeric and pericentromeric position on part of the chromosomes; some interstitial C-bands were also present. Heteromorphic nucleolus organizer regions (NORs) were detected in two chromosome pairs of the specimen from the Amazon River. The chromosome number and karyotype characteristics are similar to those of other Gymnotidae species. The genera Electrophorus and Gymnotus are positioned as the basal lineages in the Gymnotiformes phylogeny.