Landscape characteristics of <Emphasis Type="Italic">Rhizophora mangle</Emphasis> forests and propagule deposition in coastal environments of Florida (USA)

Field dispersal studies are seldom conducted at regional scales even though reliable information on mid-range dispersal distance is essential for models of colonization. The purpose of this study was to examine the potential distance of dispersal of Rhizophora mangle propagules by comparing deposition density with landscape characteristics of mangrove forests. Propagule density was estimated at various distances to mangrove sources (R. mangle) on beaches in southwestern Florida in both high-and low-energy environments, either facing open gulf waters vs. sheltered, respectively. Remote sensing and Geographic Information Systems were used to identify source forests and to determine their landscape characteristics (forest size and distance to deposition area) for the regression analyses. Our results indicated that increasing density of propagules stranded on beaches was related negatively to the distance of the deposition sites from the nearest stands of R. mangle and that deposition was greatly diminished 2 km or more from the source. Measures of fragmentation such as the area of the R. mangle forests were related to propagule deposition but only in low-energy environments. Our results suggest that geographic models involving the colonization of coastal mangrove systems should include dispersal dynamics at mid-range scales, i.e., for our purposes here, beyond the local scale of the forest and up to 5 km distant. Studies of mangrove propagule deposition at various spatial scales are key to understanding regeneration limitations in natural gaps and restoration areas. Therefore, our study of mid-range propagule dispersal has broad application to plant ecology, restoration, and modeling.     

Cryptosporidiosis – an occupational risk and a disregarded disease in Estonia

Background

Cases of cryptosporidiosis have not been officially reported in Estonia after the year 2000, and the disease appears to be either under-diagnosed or under-reported.

Findings

Based on a human case of cryptosporidiosis contracted during faecal sampling in dairy farms, cattle considered to be sources of infection were analysed for Cryptosporidium spp. by a modified Ziehl Neelsen technique and molecular typing. C. parvum subtype IIaA16G1R1 was detected from the human case and from calves from one of nine farms enrolled in the study providing strong circumstantial evidence of zoonotic transmission from calves to humans.

Conclusion

Cryptosporidiosis presents an occupational risk to people with cattle contact, and may also be a risk to the human population in general. Thus increased public and medical awareness is warranted.     

Parasite population dynamics in pigs infected with Trichuris suis and Oesophagostomum dentatum

The aim of the present study was to investigate the population dynamics and potential interactions between Trichuris suis and Oesophagostomum dentatum in experimentally co-infected pigs, by quantification of parasite parameters such as egg excretion, worm recovery and worm location. Forty-eight helminth naïve pigs were allocated into four groups. Group O was inoculated with 20 O. dentatum L₃/kg/day and Group T with 10 T. suis eggs/kg/day. Group OT was inoculated with both 20 O. dentatum L₃/kg/day and 10 T. suis eggs/kg/day, while Group C was kept as an uninfected control group. All inoculations were trickle infections administered twice weekly and were continued until slaughter. Faecal samples were collected from the rectum of all pigs at day 0, and twice weekly from 2 to 9 weeks post first infection (wpi). Six pigs from each group were necropsied 5 wpi and the remaining 6 pigs from each group were necropsied 10 wpi. The faecal egg counts (FEC) and total worm burdens of O. dentatum were dramatically influenced by the presence of T. suis, with significantly lower mean FECs and worm burdens at 5 and 10 wpi compared to single infected pigs. Furthermore, in the presence of T. suis we found that O. dentatum was located more posteriorly in the gut. The changes in the Trichuris population were less prominent, but faecal egg counts, worm counts 5 wpi (57% recovered vs. 39%) and the proportion of infected animals at 10 wpi were higher in Group OT compared to Group T. The location of T. suis was unaffected by the presence of O. dentatum. These results indicate an antagonistic interaction between T. suis and O. dentatum which is dominated by T. suis.     

NGOs Enhance State Wildlife Agencies’ Capacity to Meet Public Trust Doctrine Obligations

State wildlife agencies (SWAs) manage natural resources for the benefit of the common good. However, effective management in today’s complex world requires institutional capacity that can address specific challenges. Nongovernmental organizations can enhance SWAs’ ability to manage wildlife as a public resource for which competing demands exist. The Wildlife Conservation Society (WCS) led a participatory process to identify a suite of landscape species representative of habitats and human-caused threats in the Adirondack Park of northern New York. This effort benefitted the management of resources under the public trust doctrine. WCS brought additional capacity, specifically personnel, resources, programming, and credibility with partners, to conservation initiatives focused on boreal birds, moose, and black bears over a 15-year period in the Adirondack Park, NY. This investment resulted in several long-term projects that enhanced the NYS Department of Environmental Conservation’s ability to provide improved management and multiple benefits from these resources to the public.     

Single-molecule measurement of protein folding kinetics

In order to investigate the behavior of single molecules under conditions far from equilibrium, we have coupled a microfabricated laminar-flow mixer to a confocal optical system. This combination enables time-resolved measurement of F?rster resonance energy transfer after an abrupt change in solution conditions. Observations of a small protein show the evolution of the intramolecular distance distribution as folding progresses. This technique can expose subpopulations, such as unfolded protein under conditions favoring the native structure, that would be obscured in equilibrium experiments.     

Genetic structure of the purebred domestic dog

We used molecular markers to study genetic relationships in a diverse collection of 85 domestic dog breeds. Differences among breeds accounted for approximately 30% of genetic variation. Microsatellite genotypes were used to correctly assign 99% of individual dogs to breeds. Phylogenetic analysis separated several breeds with ancient origins from the remaining breeds with modern European origins. We identified four genetic clusters, which predominantly contained breeds with similar geographic origin, morphology, or role in human activities. These results provide a genetic classification of dog breeds and will aid studies of the genetics of phenotypic breed differences.