RESUMEN
We examined the associations between intestinal helminth infracommunity structure and infection parameters and the age, size, and year and region of collection of 130 female lesser scaup (Aythya affinis) during their 2014-2015 spring migrations through the upper Midwest, USA. We identified a total of 647,174 individual helminths from 40 taxa, including 20 trematodes, 14 cestodes, 4 nematodes and 2 acanthocephalans parasitizing lesser scaup within the study area. Lesser scaup were each infected with 2-23 helminth taxa. One digenean, Plenosoma minimum, is reported for the first time in lesser scaup and in the Midwest. Mean trematode abundance and total helminth abundance was significantly less in 2015 than 2014, and we suspect that colder weather late in 2015 impacted the intermediate host fauna and caused the observed differences. Brillouin's species diversity of helminths was greatest in the northernmost region of the study area, which coincides with the range of a non-indigenous snail that indirectly causes annual mortality events of lesser scaup. While host age and size were not determined to be influential factors of helminth infracommunity structure, non-parametric ordination and permutational analysis of co-variance revealed that year and region of collection explained differences in helminth infracommunities. Our results suggest that spatiotemporal variations play an important role in the structure of intestinal helminth infracommunities found in migrating lesser scaup hosts, and may therefore impact host ability to build endogenous reserves at certain stopover locations in the Midwest.
Asunto(s)
Anseriformes/parasitología , Enfermedades de las Aves/epidemiología , Enfermedades de las Aves/parasitología , Helmintos/clasificación , Helmintos/aislamiento & purificación , Parasitosis Intestinales/veterinaria , Animales , Biodiversidad , Femenino , Helmintiasis/epidemiología , Helmintiasis/parasitología , Parasitosis Intestinales/epidemiología , Parasitosis Intestinales/parasitología , Medio Oeste de Estados Unidos/epidemiología , Carga de Parásitos , Análisis Espacio-TemporalRESUMEN
In Caulobacter crescentus, morphogenic events, such as cytokinesis, the establishment of asymmetry and the biogenesis of polar structures, are precisely regulated during the cell cycle by internal cues, such as cell division and the initiation of DNA replication. Recent studies have revealed that the converse is also true. That is, differentiation events impose regulatory controls on other differentiation events, as well as on progression of the cell cycle. Thus, there are pathways that sense the assembly of structures or the localization of complexes and then transduce this information to subsequent biogenesis or cell cycle events. In this review, we examine the interplay between flagellar assembly and the C. crescentus cell cycle.