Characterization of an inhibitor of hepatic cholesterogenesis present in hepatic microsomes.

An inhibitor of hepatic cholesterol synthesis present in hepatic microsomes can be solubilized either by an acetone or an ethanol powder preparation. Other methods such as methanol and chloroform:methanol powder preparations and treatment with EDTA do not solubilize the factor. The factor appears to be proteinaceous since its activity is lost after exposure to proteolytic enzymes and heat treatment. In addition, the inhibitor does not require a phospholipid for activity. 3this inhibitor is stable for long periods (60 hrs.) at room temperature and can be isolated in good yield from liver maintained at 4 degrees C for 8 hours postmortem.     

Estimating Influenza Disease Burden from Population-Based Surveillance Data in the United States

Annual estimates of the influenza disease burden provide information to evaluate programs and allocate resources. We used a multiplier method with routine population-based surveillance data on influenza hospitalization in the United States to correct for under-reporting and estimate the burden of influenza for seasons after the 2009 pandemic. Five sites of the Influenza Hospitalization Surveillance Network (FluSurv-NET) collected data on the frequency and sensitivity of influenza testing during two seasons to estimate under-detection. Population-based rates of influenza-associated hospitalization and Intensive Care Unit admission from 2010–2013 were extrapolated to the U.S. population from FluSurv-NET and corrected for under-detection. Influenza deaths were calculated using a ratio of deaths to hospitalizations. We estimated that influenza-related hospitalizations were under-detected during 2010-11 by a factor of 2.1 (95%CI 1.7–2.9) for age < 18 years, 3.1 (2.4–4.5) for ages 18-64 years, and 5.2 (95%CI 3.8–8.3) for age 65+. Results were similar in 2011-12. Extrapolated estimates for 3 seasons from 2010–2013 included: 114,192–624,435 hospitalizations, 18,491–95,390 ICU admissions, and 4,915–27,174 deaths per year; 54–70% of hospitalizations and 71–85% of deaths occurred among adults aged 65+. Influenza causes a substantial disease burden in the U.S. that varies by age and season. Periodic estimation of multipliers across multiple sites and age groups improves our understanding of influenza detection in sentinel surveillance systems. Adjusting surveillance data using a multiplier method is a relatively simple means to estimate the impact of influenza and the subsequent value of interventions to prevent influenza.     

Diet of the gracile mouse opossum Gracilinanus agilis (Didelphimorphia: Didelphidae) in a neotropical savanna: intraspecific variation and resource selection

Investigation of the effect of endogenous and exogenous factors on the diet of animals is necessary for a better understanding of their feeding habits. This approach can provide relevant information on the autoecology of a species and its ecological interactions. We investigated the composition and intraspecific variation in the diet of the marsupial Gracilinanus agilis in areas of dry woodland forests (i.e., cerradão) in the Cerrado of Central Brazil, taking into consideration the availability of prey (arthropods) in the environment. We found insects, spiders, birds, and fruits in the scats of G. agilis. Insects (orders Hymenoptera, Isoptera, Hemiptera, and Coleoptera) and fruits were the most frequently consumed resources. Males fed more heavily on insects than females did, whereas during the warm–wet season (October to April), the reproductive females fed on insects more than the nonreproductive females did. On the other hand, the consumption of fruits and vertebrates did not vary between seasons, sexes, or according to female reproductive condition. Moreover, reproductive females fed more frequently on ants and beetles than nonreproductive females did. We also detected both positive (for Isoptera and Hemiptera) and negative (for Hymenoptera) selection of insects during the cool–dry season, whereas in the warm–wet season, these resources were consumed according to their availability in the environment. Our study revealed that G. agilis is an insectivore–omnivore species, but fruits also are a relevant part of its diet. This marsupial seemed to select their prey qualitatively according to its energy demands and nutritional requirements.     

Predominance of single paternity in the black spiny-tailed iguana: conservation genetic concerns for female-biased hunting

Because of female-biased illegal harvesting, knowledge about the genetic mating system of the black spiny-tailed iguana Ctenosaura pectinata is of primary interest for the conservation of this threatened species. Based on the high levels of multiple paternity found in clutches of many other reptiles, particularly in lizards, it is hypothesised that multiple paternity may also be common in black iguanas. This was investigated by using microsatellite DNA to estimate the number of males siring nine litters (9 mothers, 121 offspring genotyped at ten polymorphic loci) of black iguanas. Contrary to expectations, only 11% of sampled black iguana females produced litters consistent with being sired by multiple males. These data are the first evidence for the predominance of single paternity within an iguanid lizard, and suggest that black iguana may be more susceptible to loss of genetic variation in the face of gender-biased over-hunting pressure than previously thought.     

Combining contemporary and ancient DNA in population genetic and phylogeographical studies

The analysis of ancient DNA in a population genetic or phylogeographical framework is an emerging field, as traditional analytical tools were largely developed for the purpose of analysing data sampled from a single time point. Markov chain Monte Carlo approaches have been successfully developed for the analysis of heterochronous sequence data from closed panmictic populations. However, attributing genetic differences between temporal samples to mutational events between time points requires the consideration of other factors that may also result in genetic differentiation. Geographical effects are an obvious factor for species exhibiting geographical structuring of genetic variation. The departure from a closed panmictic model require researchers to either exploit software developed for the analysis of isochronous data, take advantage of simulation approaches using algorithms developed for heterochronous data, or explore approximate Bayesian computation. Here, we review statistical approaches employed and available software for the joint analysis of ancient and modern DNA, and where appropriate we suggest how these may be further developed.