Identification of Plakortide E from the Caribbean Sponge Plakortis halichondroides as a Trypanocidal Protease Inhibitor using Bioactivity-Guided Fractionation

In this paper, we report new protease inhibitory activity of plakortide E towards cathepsins and cathepsin-like parasitic proteases. We further report on its anti-parasitic activity against Trypanosoma brucei with an IC₅₀ value of 5 μM and without cytotoxic effects against J774.1 macrophages at 100 μM concentration. Plakortide E was isolated from the sponge Plakortis halichondroides using enzyme assay-guided fractionation and identified by NMR spectroscopy and mass spectrometry. Furthermore, enzyme kinetic studies confirmed plakortide E as a non-competitive, slowly-binding, reversible inhibitor of rhodesain.     

Demographic consequences of anthropogenic influences: Florida black bears in north-central Florida

Anthropogenic habitat fragmentation poses a serious threat to conservation of large carnivores, due to their extensive movements and potential conflicts with humans. We studied the population ecology of Florida black bears (Ursus americanus floridanus) for 6 years in two study areas in north-central Florida: Ocala National Forest (ONF), a contiguous forested habitat, and an adjacent residential community of Lynne, a fragmented habitat with substantial human activities. We estimated age-specific survival and fecundity rates of bears using data from radio-collared bears, and parameterized and analyzed stage-structured matrix population models for the two study sites and also for data pooled from both sites. Annual survival rates of adult females were lower in Lynne (0.776 ± 0.074) than in ONF (0.966 ± 0.023). While cub survival rates were higher in Lynne (0.507 ± 0.135) than in ONF (0.282 ± 0.109), the rates at both sites were substantially lower than those reported for other black bear populations. Age-specific fecundities did not vary between sites. The asymptotic population growth rate for ONF was greater than one, whereas that for Lynne was less than one. Our results suggest that anthropogenic influences (primarily road density and vehicular traffic, through their effect on adult survival) can substantially affect the population dynamics of Florida black bears and other large carnivores with large home ranges. We recommend efforts such as constructing highway underpasses, which could reduce road-related mortalities, to ensure long-term persistence of Florida black bears facing threats from rapidly increasing human influences.     

Genetic restoration of the Florida panther

The rediscovery of remnant Florida panthers (Puma concolor coryi) in southern Florida swamplands prompted a program to protect and stabilize the population. In 1995, conservation managers translocated eight female pumas (P. c. stanleyana) from Texas to increase depleted genetic diversity, improve population numbers, and reverse indications of inbreeding depression. We have assessed the demographic, population-genetic, and biomedical consequences of this restoration experiment and show that panther numbers increased threefold, genetic heterozygosity doubled, survival and fitness measures improved, and inbreeding correlates declined significantly. Although these results are encouraging, continued habitat loss, persistent inbreeding, infectious agents, and possible habitat saturation pose new dilemmas. This intensive management program illustrates the challenges of maintaining populations of large predators worldwide.     

Village chickens management in Wolaita zone of southern Ethiopia

Little effort has been made to improve village chickens housing, feeding, and health care. Due to this, the amount of output obtained is usually low. The aim of this study was to elicit farmers’ knowledge on the routine husbandry practices of village chickens. One hundred nineteen farmers were one-on-one interviewed in the highland and lowland areas of Wolaita zone (southern Ethiopia) to generate the dataset used in this analysis. We found that all the respondents supplemented the scavenging chickens with locally available feed resources. However, the amount of supplementary feeds provided hardly meets the nutritional requirement of the flock. As a result, farmers were forced to practice a sort of preferential feeding mainly based on laying performance and the scavenging ability of different classes of the family flock. Moreover, there is a wide difference in the amount and type of feed available among seasons. This variation has forced farmers to resort on strategic supplementation to overcome the adverse effect of inherent feed (grain) scarcity on chickens’ performance especially during wet season. Feed loss should be kept at a minimum by using feeding troughs, and a fraction of money obtained from selling of the chickens and eggs needs to be set aside to purchase feed. The risk of disease was higher during main rain season (June to September). Besides providing sanitary condition and feed supplementation, capacitating the veterinary service and validating the efficacy of ethno-veterinary practices through objective studies is required to improve the health status of village chickens. Majority of the farmers use rudimentary types of in-house built shelters to protect their chickens from adverse effects of bad weather, predation, and theft. This indicates the importance of constructing proper types of shelters from locally (freely) available or inexpensive materials. The existing tradition of responsibility sharing among family members while doing the routine husbandry practices needs to be strengthened to maximize the efficient use of family’s labor force. This improvement plan needs to be mainly implemented through adoption of the existing best traditional practices and through the rational use of cheap and readily available local resources.     

Uses and flock management practices of scavenging chickens in Wolaita Zone of southern Ethiopia

Rearing of scavenging chickens is among the most commonly practiced farm activities in Ethiopia. This system is dominated by indigenous chickens. Output from indigenous chickens is low due to poor management and absence of intense selection that is intended to improve economically important traits. This showed that village chickens are rather evolved for adaptation traits. However, the level of risk is low, and this has made rearing of scavenging chickens a choice of farm activity for smallholder farmers. The objective of this study was to characterize the scavenging chickens’ production system in Wolaita Zone. Single-visit survey involving individual interview of 119 farmers and 6 focus group discussions was used to collect the data. Our results showed that rearing of scavenging chickens was constrained especially by disease and predation problems. However, farmers proposed a set of solutions to minimize the effect of these problems. Rearing of scavenging chickens fulfils the multi-functional need of the society. This system has special features because it can sustain in its own without the need for modern commercial chicken farming facilities. However, farmers also reported the drawbacks of rearing of scavenging chickens and these mainly include uproot of garden crops and tiresomeness of the night watching. Selection of chickens was mainly depending on physically observed traits like body size and plumage colour. The initial foundation flock was mainly obtained from the local market. The ideal place for scavenging chickens production is the one that has intermediate weather condition and has some trees that can be used as shade; however, it was substantiated that it has to be free from bush and shrubs, weeds and wet lands. Therefore, these pieces of knowledge embedded among smallholder farmers need to be well documented and synthesized to design an appropriate type of technology packages that can be communicated back to farmers to improve productivity of the scavenging chickens.     

Reintroducing endangered Vancouver Island marmots: Survival and cause-specific mortality rates of captive-born versus wild-born individuals

Recovery of the endangered Vancouver Island marmot (Marmota vancouverensis) is contingent upon releases of captive-born marmots into natural habitats. Success of such re-introduction programs largely depends on the ability of released animals to survive in the wild. However, whether and to what extent survival and cause-specific mortality rates of captive-born marmots differ from those of their wild-born counterparts remains unknown. We used radio-telemetry (1992–2007) and mark-resighting (1987–2007) data to estimate seasonal and annual survival rates of the Vancouver Island marmot, to compare survival and cause-specific mortality rates of captive-born marmots that have been released into the natural habitat with those of wild-born marmots, and to test for the effect of age-at-release on survival of the released marmots. Analysis of radio-telemetry data suggested no difference in survival of males versus females. However, annual survival of captive-born marmots released into the wild was low (S = 0.605; 95% CI = 0.507–0.696) compared to wild-born marmots (S = 0.854; 95% CI = 0.760–0.915). Marmots released as 2-year-old or older survived more successfully than those released as yearlings. Additional forensic evidence reinforced the idea that predation was the most important cause of mortality. Causes of death differed significantly between captive-born and wild-born marmots. Predation by golden eagles (Aquila chrysaetus) was the most important cause of mortality for captive-born marmots, whereas predation by wolves (Canis lupus) and cougars (Felis concolor) was more important for wild-born marmots. Age-specific apparent annual survival rate, estimated using the combined mark-resighting and radio-telemetry data, was lowest for pups (S = 0.500; 95% CI = 0.375–0.616) and highest for yearlings and adults (S = 0.656; 95% CI = 0.604–0.705); and apparent survival of 2-year-old was similar to that of yearlings and adults (S = 0.649; 95% CI = 0.527–0.754). Our results, based on the analysis of radio-telemetry data, suggest that delaying release of captive-born marmots until 2 years of age may enhance their probability of survival in the wild, and will likely improve the success of the release program.     

Genetic Introgression and the Survival of Florida Panther Kittens

Estimates of survival for the young of a species are critical for population models. These models can often be improved by determining the effects of management actions and population abundance on this demographic parameter. We used multiple sources of data collected during 1982-2008 and a live-recapture dead-recovery modeling framework to estimate and model survival of Florida panther (Puma concolor coryi) kittens (age 0-1 year). Overall, annual survival of Florida panther kittens was 0.323 ± 0.071 (SE), which was lower than estimates used in previous population models. In 1995, female pumas from Texas (P. c. stanleyana) were released into occupied panther range as part of an intentional introgression program to restore genetic variability. We found that kitten survival generally increased with degree of admixture: F₁ admixed and backcrossed to Texas kittens survived better than canonical Florida panther and backcrossed to canonical kittens. Average heterozygosity positively influenced kitten and older panther survival, whereas index of panther abundance negatively influenced kitten survival. Our results provide strong evidence for the positive population-level impact of genetic introgression on Florida panthers. Our approach to integrate data from multiple sources was effective at improving robustness as well as precision of estimates of Florida panther kitten survival, and can be useful in estimating vital rates for other elusive species with sparse data.