RESUMEN
The freshwater raphidophyte Gonyostomum semen forms extensive summer blooms in northern European humic lakes. The development of these blooms might be facilitated by a lack of natural top-down control, as few zooplankton species are able to prey on these large algal cells (up to 100 µm) that expel trichocysts upon physical stress. In this study, we describe a small ciliate species (< 17 µm) that preys on G. semen by damaging the cell membrane until cytoplasm and organelles spill out. Sequencing of clonal cultures of the ciliate tentatively identified it as the prostomatid species Urotricha pseudofurcata. Grazing experiments illustrated that feeding by U. cf. pseudofurcata can significantly reduce cell concentrations of the microalga. However, differences in cell size and growth rate between two investigated ciliate strains resulted in noticeably different grazing pressure. Environmental sequencing data from five different lakes supported potential interactions between the two species. Urotricha cf. pseudofurcata might, thus, play an important role in aquatic ecosystems that are regularly dominated by G. semen, reducing the abundance of this bloom-forming microalga and enabling transfer of organic carbon to higher trophic levels.
Asunto(s)
Cilióforos , Microalgas , Ecosistema , Semen , Carbono , LagosRESUMEN
Herdsman-reported disease prevalence is widely used in veterinary epidemiologic studies, especially for diseases with visible external lesions; however, the accuracy of such reports is rarely validated. Thus, we used latent class analysis in a Bayesian framework to compare sensitivity and specificity of herdsman reporting with virus neutralization testing and use of 3 nonstructural protein ELISAs for estimates of foot-and-mouth disease (FMD) prevalence on the Adamawa plateau of Cameroon in 2000. Herdsman-reported estimates in this FMD-endemic area were comparable to those obtained from serologic testing. To harness to this cost-effective resource of monitoring emerging infectious diseases, we suggest that estimates of the sensitivity and specificity of herdsmen reporting should be done in parallel with serologic surveys of other animal diseases.
Asunto(s)
Virus de la Fiebre Aftosa , Fiebre Aftosa/diagnóstico , Fiebre Aftosa/epidemiología , Pruebas de Neutralización/métodos , Pruebas de Neutralización/normas , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/virología , Estudios Transversales , Virus de la Fiebre Aftosa/inmunología , Prevalencia , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Mannose-binding lectin (MBL) plays a major role in the immune response as a soluble pattern-recognition receptor. MBL deficiency and susceptibility to different types of infections have been subject to extensive studies over the last decades. In humans and chickens, several studies have shown that MBL participates in the protection of hosts against virus infections. Infectious bronchitis (IB) is a highly contagious disease of economic importance in the poultry industry caused by the coronavirus infectious bronchitis virus (IBV). MBL has earlier been described to play a potential role in the pathogenesis of IBV infection and the production of IBV-specific antibodies, which may be exploited in optimising IBV vaccine strategies. The present study shows that MBL has the capability to bind to IBV in vitro. Chickens from two inbred lines (L10H and L10L) selected for high or low MBL serum concentrations, respectively, were vaccinated against IBV with or without the addition of the MBL ligands mannan, chitosan and fructooligosaccharide (FOS). The addition of MBL ligands to the IBV vaccine, especially FOS, enhanced the production of IBV-specific IgG antibody production in L10H chickens, but not L10L chickens after the second vaccination. The addition of FOS to the vaccine also increased the number of circulating CD4+ cells in L10H chickens compared to L10L chickens. The L10H chickens as well as the L10L chickens also showed an increased number of CD4-CD8α-γδ T-cells when an MBL ligand was added to the vaccine, most pronouncedly after the first vaccination. As MBL ligands co-administered with IBV vaccine induced differences between the two chicken lines, these results indirectly suggest that MBL is involved in the immune response to IBV vaccination. Furthermore, the higher antibody response in L10H chickens receiving vaccine and FOS makes FOS a potential adjuvant candidate in an IBV vaccine.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Infecciones por Coronavirus/prevención & control , Virus de la Bronquitis Infecciosa/inmunología , Lectina de Unión a Manosa/biosíntesis , Oligosacáridos/inmunología , Receptores de Reconocimiento de Patrones/biosíntesis , Vacunas Virales , Adyuvantes Inmunológicos , Animales , Animales Endogámicos , Anticuerpos Antivirales/sangre , Formación de Anticuerpos , Pollos , Quitosano/inmunología , Infecciones por Coronavirus/inmunología , Inmunoglobulina G/sangre , Ligandos , Mananos/inmunología , Lectina de Unión a Manosa/agonistas , Lectina de Unión a Manosa/sangre , Receptores de Reconocimiento de Patrones/agonistas , Receptores de Reconocimiento de Patrones/sangre , VacunaciónRESUMEN
In the beginning were neither B cells nor T cells nor antibodies, but innate immune defense alone. The primary functional theme of innate immunity is the distinction between self and non-self, which is maintained by a vast number of cellular and subcellular components. In this context, the immense importance of the Toll-like receptors (TLRs) is well established. Positive (Darwinian) selection seems to be acting on the ligand-binding domains of these molecules, suggesting a selection pattern similar to that previously observed in the MHC proteins. In sharp contrast to TLRs, the biological significance of mannan-binding lectin (MBL) is controversial, and, concerning humans, it has been suggested that low concentration of MBL in serum represents a selective advantage. In this mini-review, based on a doctoral thesis, evolutionary aspects of TLRs and MBL are discussed.
Asunto(s)
Lectina de Unión a Manosa/metabolismo , Receptores Toll-Like/metabolismo , Animales , Humanos , Inmunidad Innata , Plantas/metabolismoRESUMEN
During the last decade, the Toll-like receptors (TLRs) have been extensively studied, and their immense importance in innate immunity is now being unveiled. Here, we report pronounced differences--probably reflecting the domestication process and differences in selective pressure--between wild boars and domestic pigs regarding single nucleotide polymorphisms (SNPs) in TLR genes. The open reading frames of TLR1, TLR2, and TLR6 were sequenced in 25 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace, and Large White origin. In total, 20, 27, and 26 SNPs were detected in TLR1, TLR2, and TLR6, respectively. In TLR1 and TLR2, the numbers of SNPs detected were significantly lower (P < or = 0.05, P < or = 0.01) in the wild boars than in the domestic pigs. In the wild boars, one major high frequency haplotype was found in all three genes, while the same pattern was exhibited only by TLR2 in the domestic pigs. The relative frequency of non-synonymous (dN) and synonymous (dS) SNPs was lower for the wild boars than for the domestic pigs in all three genes. In addition, differences in diversity between the genes were revealed: the mean heterozygosity at the polymorphic positions was markedly lower in TLR2 than in TLR1 and TLR6. Because of its localization--in proximity of the bound ligand--one of the non-synonymous SNPs detected in TLR6 may represent species-specific function on the protein level. Furthermore, the codon usage pattern in the genes studied deviated from the general codon usage pattern in Sus scrofa.
Asunto(s)
Polimorfismo de Nucleótido Simple , Sus scrofa/genética , Receptor Toll-Like 1/genética , Receptor Toll-Like 2/genética , Receptor Toll-Like 6/genética , Animales , Modelos Moleculares , Receptor Toll-Like 1/química , Receptor Toll-Like 2/química , Receptor Toll-Like 6/químicaRESUMEN
Se evaluó la efectividad de un ensayo enmunoenzimático de electrotransferencia (EITB) para la detección de anticuerpos contra antígenos de replicación del virus de la fiebre aftosa (VFA) en bovinos expuestos al mismo. El ensayo EITB, que utiliza como sondas serológicas antígenos virales no estructurales producidos por bioingeniería y altamente purificados, se comparó con la prueba tradicional de inmunodifusión en gel de agar (prueba VIAA), que emplea un antígeno asociado a la infección viral parcialmente purificado. Se recomienda el uso del EITB como una prueba sensible, segura, rápida y económica pra la detección especifica de exposición en el campo