Interpopulation Comparisons of Antipredator Defense Behavior of the Thorn‐Tailed Rayadito (Aphrastura spinicauda)

The high impact of predators on breeding success has favored the evolution of diverse behavioral strategies that enhance both individual survivorship and reproductive success. Self‐ and nest‐defense against predators are inter‐related behaviors that vary according to life history traits and the risks involved in defense. In addition, interpopulation differences in the composition of predator guilds, and hence predation pressures, may result in geographic variation in antipredator defense strategies. It is generally accepted that the absence of predators could drive the loss of antipredator behavior. However, it is unclear how species respond if one type of predator (e.g., a specialized nest predator) is absent but others are present. The multipredator hypothesis suggests that the absence of only a few predators is not sufficient to drive a change or loss of antipredator behavior in a species. We examined interpopulation variation in defense behavior in the thorn‐tailed rayadito (Aphrastura spinicauda), a suboscine bird inhabiting a wide latitudinal range in southern South America. In populations where nest predators were either present or absent, we examined the responses of rayaditos to an adult predator (an owl) and to a nest predator (a marsupial). Owl‐defense behavior involved more intense and longer responses than marsupial‐defense. This suggests that adult rayaditos may allocate more energy to defend themselves than their young. However, because the presence of adult predators near the nest also prevents parents from feeding the nestlings, owl‐defense may simultaneously represent a form of nest‐defense. No differences in marsupial‐defense were found among the three sampled populations, despite the absence of native mammalian nest predators in one population. The lack of variation in nest‐defense behavior provides some support for the multipredator hypothesis, although the high interpopulation gene flow in this species could also contribute to this behavior's maintenance.     

Synthesis of 2,3:4,6-di-O-isopropylidene-D-allopyranose from D-glucose

2,3:4,6-Di-O-isopropylidene-d-allopyranose can be conveniently prepared from d-glucose via a synthetic sequence, which includes Mitsunobu inversion at O-3, di-O-isopropylidenation of phenyl-1-thio-d-alloside and anomeric deprotection on treatment with NBS/CaCO3.     

Gender and Age Differences in Hourly and Daily Patterns of Sedentary Time in Older Adults Living in Retirement Communities

Background

Total sedentary time varies across population groups with important health consequences. Patterns of sedentary time accumulation may vary and have differential health risks. The purpose of this study is to describe sedentary patterns of older adults living in retirement communities and illustrate gender and age differences in those patterns.

Methods

Baseline accelerometer data from 307 men and women (mean age = 84±6 years) who wore ActiGraph GT3X+ accelerometers for ≥ 4 days as part of a physical activity intervention were classified into bouts of sedentary time (<100 counts per minute). Linear mixed models were used to account for intra-person and site-level clustering. Daily and hourly summaries were examined in mutually non-exclusive bouts of sedentary time that were 1+, 5+, 10+, 20+, 30+, 40+, 50+, 60+, 90+ and 120+ minutes in duration. Variations by time of day, age and gender were explored.

Results

Men accumulated more sedentary time than women in 1+, 5+, 10+, 20+, 30+, 40+, 50+ and 60+ minute bouts; the largest gender-differences were observed in 10+ and 20+ minute bouts. Age was positively associated with sedentary time, but only in bouts of 10+, 20+, 30+, and 40+ minutes. Women had more daily 1+ minute sedentary bouts than men (71.8 vs. 65.2), indicating they break up sedentary time more often. For men and women, a greater proportion of time was spent being sedentary during later hours of the day than earlier. Gender differences in intra-day sedentary time were observed during morning hours with women accumulating less sedentary time overall and having more 1+ minute bouts.

Conclusions

Patterns identified using bouts of sedentary time revealed gender and age differences in the way in which sedentary time was accumulated by older adults in retirement communities. Awareness of these patterns can help interventionists better target sedentary time and may aid in the identification of health risks associated with sedentary behavior. Future studies should investigate the impact of patterns of sedentary time on healthy aging, disease, and mortality.     

Antioxidant action of propolis on mouse lungs exposed to short-term cigarette smoke

Propolis is a natural product with antioxidant properties. In this study, we tested the efficacy of propolis against acute lung inflammation (ALI) caused by cigarette smoke (CS). C57BL6 male mice were exposed to CS and treated with propolis (200 mg/kg orally, CS+P) or only with propolis (P). A Control group treated with propolis was sham-smoked (Control+P). We collected the lungs for histological and biochemical analyses. We observed an increase in alveolar macrophages and neutrophils in the CS group compared with the Control+P. These counts reduced in the CS+P group compared to the CS group. The treatment with propolis normalized all biochemical parameters in the CS+P group compared with the CS group, including nitrite, myeloperoxidase level, antioxidant enzyme activities (superoxide dismutase, catalase and glutathione peroxidase), reduced glutathione/oxidized glutathione ratio and malondialdehyde. Additionally, TNF-α expression reduced in the CS+P group when compared with the CS group. These data imply a potential antioxidant and anti-inflammatory role for propolis with regard to ALI caused by CS in mice.     

Association of hepatitis C virus NS5B variants with resistance to new antiviral drugs among untreated patients

Mutations located in the 109-amino acid fragment of NS5B are typically associated with resistance to interferon (IFN) and ribavirin (RIB) and to new antiviral drugs. The prevalence of these mutations was examined in 69 drug-na?ve individuals with hepatitis C virus (HCV) infections in Rio de Janeiro, Brazil. Mutations related to non-response to IFN/RIB were observed in all subtypes studied (1a, 1b, 2b, 3a and 4). The most common mutation was Q309R, present in all subtypes, except subtype 2b with frequency above 20%. D244N was detected only in subtype 3a and A333E was detected only in subtype 2b. We did not detect the S282T, S326G or T329I mutations in any of the samples analysed. Of note, the C316N mutation, previously related to a new non-nucleoside compound (HCV796 and AG-021541), was observed in only eight of 33 (24%) samples from subtype 1b. Site 316 was under positive selection in this HCV variant. Our data highlight the presence of previously described resistance mutations in HCV genotypes from drug-na?ve patients.     

How Do Hunter-Gatherer Children Learn Subsistence Skills?

Hunting and gathering is, evolutionarily, the defining subsistence strategy of our species. Studying how children learn foraging skills can, therefore, provide us with key data to test theories about the evolution of human life history, cognition, and social behavior. Modern foragers, with their vast cultural and environmental diversity, have mostly been studied individually. However, cross-cultural studies allow us to extrapolate forager-wide trends in how, when, and from whom hunter-gatherer children learn their subsistence skills. We perform a meta-ethnography, which allows us to systematically extract, summarize, and compare both quantitative and qualitative literature. We found 58 publications focusing on learning subsistence skills. Learning begins early in infancy, when parents take children on foraging expeditions and give them toy versions of tools. In early and middle childhood, children transition into the multi-age playgroup, where they learn skills through play, observation, and participation. By the end of middle childhood, most children are proficient food collectors. However, it is not until adolescence that adults (not necessarily parents) begin directly teaching children complex skills such as hunting and complex tool manufacture. Adolescents seek to learn innovations from adults, but they themselves do not innovate. These findings support predictive models that find social learning should occur before individual learning. Furthermore, these results show that teaching does indeed exist in hunter-gatherer societies. And, finally, though children are competent foragers by late childhood, learning to extract more complex resources, such as hunting large game, takes a lifetime.     

Microbial production of ellagic acid and biodegradation of ellagitannins

In the last years, tannin biodegradation has been the subject of a lot of studies due to its commercial importance and scientific relevance. Tannins are molecules of low biodegradation and represent the main chemical group of natural anti-microbials occurring in the plants. Among the different kinds of tannins, ellagitannins represent the group less studied manly due to their diversity and chemical complexity. The general outline of this work includes information on tannins, their classification and properties, biodegradation, ellagic acid production, and potential applications. In addition, it describes molecular, catalytic, and functional information. Special attention has been focused on the biodegradation of ellagitannins describing the possible role of microbial enzymes in the production of ellagic acid.     

The Ranging Costs of a Fallback Food: Liana Consumption Supplements Diet but Increases Foraging Effort in Howler Monkeys

Lianas are important components in the dynamics of tropical forests and represent fallback foods for some primates, yet little is known about their impact on primate ecology, behavior or fitness. Using 2 yr of field data, we investigated liana consumption and foraging effort in four groups of howler monkeys (two in bigger, more conserved forest fragments and two in smaller, less conserved fragments) to assess whether howler monkeys use lianas when and where food availability is scarce, and how liana consumption is related to foraging effort. Howler monkeys in smaller fragments spent more time consuming lianas and liana consumption was negatively related to the consumption of preferred food resources (fruit and Ficus spp.). Further, travel time was positively related to liana feeding time, but not to tree feeding time, and howler monkeys visited a greater number of food patches when feeding from liana leaves than when feeding from tree leaves. Our results suggest that these increases in foraging effort were related to the fact that lianas are mainly a source of leaves, and that liana patch size was probably smaller than tree patch size. While these results were clear when analyzing all four groups combined, however, they were not always significant in each of the groups individually. We suggest that this may be related to the differences in group size, patch size and the availability of resources among groups. Further studies are necessary to assess whether these dietary and behavioral adjustments negatively impact on the fitness and conservation of primates in fragments.