Macrophage inhibitory cytokine‐1 is associated with cognitive impairment and predicts cognitive decline – the Sydney Memory and Aging Study

Higher levels of macrophage inhibitory cytokine‐1, also known as growth differentiation factor 15 (MIC‐1/GDF15), are associated with adverse health outcomes and all‐cause mortality. The aim of this study was to examine the relationships between MIC‐1/GDF15 serum levels and global cognition, five cognitive domains, and mild cognitive impairment (MCI), at baseline (Wave 1) and prospectively at 2 years (Wave 2), in nondemented participants aged 70–90 years. Analyses were controlled for age, sex, education, Framingham risk score, history of cerebrovascular accident, acute myocardial infarction, angina, cancer, depression, C‐reactive protein, tumor necrosis factor‐α, interleukins 6 and 12, and apolipoprotein ε4 genotype. Higher MIC‐1/GDF15 levels were significantly associated with lower global cognition at both waves. Cross‐sectional associations were found between MIC‐1/GDF15 and all cognitive domains in Wave 1 (all P < 0.001) and between processing speed, memory, and executive function in Wave 2 (all P < 0.001). Only a trend was found for the prospective analyses, individuals with high MIC‐1/GDF15 at baseline declined in global cognition, executive function, memory, and processing speed. However, when categorizing MIC‐1/GDF15 by tertiles, prospective analyses revealed statistically significant lower memory and executive function in Wave 2 in those in the upper tertile compared with the lower tertile. Receiver operating characteristics (ROC) analysis was used to determine MIC‐1/GDF15 cutoff values associated with cognitive decline and showed that a MIC‐1/GDF15 level exceeding 2764 pg/ml was associated with a 20% chance of decline from normal to MCI or dementia. In summary, MIC‐1/GDF15 levels are associated with cognitive performance and cognitive decline. Further research is required to determine the pathophysiology of this relationship.     

Neuroprotective activities of bacopa,lycopene, astaxanthin, and vitamin B12 combination on oxidative stress-dependent neuronal death

Oxidative stress is considered the common effector of the cascade of degenerative events in many neurological conditions. Thus, in this paper we tested different nutraceuticals in H₂O₂ in vitro model to understand if could represent an adjuvant treatment for neurological diseases. In this study, nutraceuticals bacopa, lycopene, astaxanthin, and vitamin B12 were used alone or in combination in human neuronal differentiated SH-SY5Y cells upon hydrogen peroxide-induced injury and neuroprotective, neuronal death pathways were analyzed. The nutraceuticals analyzed were able to protect H₂O₂ cytotoxic effects, through increasing cell viability and proteins involved in neuroprotection pathways and restoring proteins involved in cell death pathways. On this basis, it is possible to propose the use of these compounds as dietary supplement for the prevention or as adjuvant to the only symptomatic treatments so far available for neurodegenerative diseases.     

Host thermoregulatory constraints predict growth of an amphibian chytrid pathogen (Batrachochytrium dendrobatidis)

1. The course and outcome of many wildlife diseases are context-dependent, and therefore change depending on the behaviour of hosts and environmental response of the pathogen.2. Contemporary declines in amphibian populations are widely attributed to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis. Despite the thermal sensitivity of the pathogen and its amphibian hosts, we do not understand how host thermal regimes experienced by frogs in the wild directly influence pathogen growth.3. We tested how thermal regimes experienced by the rainforest frog Litoria rheocola in the wild influence pathogen growth in the laboratory, and whether these responses differ from pathogen growth under available environmental thermal regimes.4. Frog thermal regimes mimicked in the laboratory accelerated pathogen growth during conditions representative of winter at high elevations more so than if temperatures matched air or stream water temperatures. By contrast, winter frog thermal regimes at low elevations slowed pathogen growth relative to air temperatures, but not water temperatures.5. The growth pattern of the fungus under frog thermal regimes matches field prevalence and intensity of infections for this species (high elevation winter > high elevation summer > low elevation winter > low elevation summer), whereas pathogen growth trajectories under environmental temperatures did not match these patterns.6. If these laboratory results translate into field responses, tropical frogs may be able to reduce disease impacts by regulating their body temperatures to limit pathogen growth (e.g., by using microhabitats that facilitate basking to reach high temperatures); in other cases, the environment may limit the ability of frogs to thermoregulate such that individuals are more vulnerable to this pathogen (e.g., in dense forests at high elevations).7. Species-specific thermoregulatory behaviour, and interactions with and constraints imposed by the environment, are therefore essential to understanding and predicting the spatial and temporal impacts of this global disease.     

《山海经》三大神木的植物学考订

《山海经》中有太阳东出扶桑、日中建木、西归若木的传说,长期以来一直存疑,争论不休,直到四川广汉三星堆遗址出土了青铜神树,才证明了传说的真实性.我们结合《山海经》等相关典籍,从植物学角度对扶桑、建木、若木的原植物进行探讨,基于典籍描述、考古资料、植物形态特征、生态习性和地理分布等,初步考订扶桑的植物原型为桦木科白桦(Betula platyphylla),建木的植物原型为杉科杉木(Cunninghamia lanceolata),若木的植物原型为木棉科木棉(Bombax ceiba).     

Effects of the winter beechmast crop on bird occurrence in British gardens

Capsule Woodland birds were significantly less likely to occur in gardens in years of high beechmast crop.

Aim To test the hypothesis that woodland species that feed on beechmast will have significantly lower occurrence rates at garden feeders in mast years.

Methods Weekly winter occurrence rates at garden feeders between 1970/71 and 1999/2000 for 40 species were analysed in relation to annual beechmast abundance, classified into low, medium and high years. A repeated-measures logistic regression model was used to assess whether beechmast abundance explained further significant variation additional to underlying seasonal and annual trends.

Results Seven species that commonly feed on beechmast showed significantly lower occurrence in gardens in years of highest beechmast abundance: Great Spotted Woodpecker Dendrocopos major, Woodpigeon Columba palumbus, Great Tit Parus major, Coal Tit Periparus ater, Nuthatch Sitta europaea, Jay Garrulus glandarius and Chaffinch Fringilla coelebs. Blackbird Turdus merula and Siskin Carduelis spinus, which showed similar significant patterns, are likely to take beechmast as elements of their diet. Pied Wagtail Motacilla alba was the only insectivorous species to show significant effects, but occurrence was lowest in years of intermediate beechmast abundance. For the latter species, this may have been due to confounding effects of temperature, but there were no such confounding effects of either temperature, or the number of bird feeders provided in gardens, for the other nine species.

Conclusion Use of artificial food sources by birds in gardens is influenced by resources in the surrounding countryside, suggesting that food provided in gardens may play a significant part in the population dynamics of these species, that population monitoring without consideration of the garden habitat may be deficient, and that volunteer-based garden bird recording may provide data that can be used as an indicator of changes in the wider countryside.     

Using independent nest survey data to validate changes in reporting rates of Martial Eagles between the Southern African Bird Atlas Project 1 and 2

Repeat monitoring is vital to measure biodiversity change. However, monitoring protocols may change, as survey techniques improve or different questions are asked. Such modifications may cause difficulties when examining changes in wildlife populations. The Southern African Bird Atlas Project (SABAP) 1 and 2 are repeat national bird surveys undertaken 20 years apart. These surveys therefore offer unrivalled potential to examine bird population changes in an African context. However, changes in protocols, both spatially and temporally, between the two surveys have raised concerns over using these data to infer population changes. In this study we use independ- ent nest survey data to test whether changes in reporting rates of Martial Eagles in the Kalahari Gemsbok National Park between the two SABAP surveys were reflected in real change in numbers of nesting pairs. From 11 quarter degree squares (QDS), covering c. 8 000 km2, both SABAP and nest surveys suggested a near identical 44% decline. Levels of agreement were weaker at the individual QDS scale, although in 67% of cases the direction of change was the same using both surveys. These results suggest that comparisons in the reporting rates between SABAP 1 and SABAP 2 accurately reflect changes in the breeding population size of this species.     

Is Foraging Time Limited During Winter? – A Feeding Experiment with Tree Sparrows Under Different Predation Risk

Small passerines are faced with a trade‐off when foraging during winter. Increasing energy reserves makes them more vulnerable to predators, while a low level of reserves exposes them to a high risk of starvation. Whether small birds under these circumstances are allowed to reduce their foraging activity under increased predation risk, for example in feeding sites more exposed to predators, remains controversial in former behavioural and ecological researches. In this study, we investigated the foraging activity of free‐living Tree Sparrow Passer montanus flocks feeding on an artificial feeding platform. The predation risk perceived by the sparrows was manipulated by placing the platform either close to or far from a bushy shelter. Foraging activity, assessed as cumulative activity of sparrows per unit time on the platform, did not differ between the low‐risk and the high‐risk conditions and did not significantly change during the day. Feeding efficiency, assessed as pecking rate, was not either reduced under the high‐risk condition. Our results suggest that sparrows were forced to feed almost continuously during the day in order to maintain their preferred level of energy reserves. However, several behavioural changes helped sparrows to adopt a safer foraging policy when feeding far from cover, as we found in another study. Altogether, sparrow flocks feeding far from cover decreased the overall foraging time (the time when any sparrow stayed on the platform) by approximately 20% as compared to the near cover condition. A possible way to maintain the same level of foraging activity despite of the reduction in overall foraging time is discussed.     

Changes in habitat use and nesting density in a declining seabird colony

Seabirds in expanding colonies select the highest-quality nesting habitat, but habitat selection has seldom been studied in declining colonies. We studied a colony of Magellanic penguins (Spheniscus magellanicus) that declined from 314,000 active nests in 1987 to 201,000 in 2014. As expected, nest quality and reproductive success were higher in burrow habitats than in other habitats, and nest density decreased with distance from shore. Contrary to predictions, the steepest declines did not occur in the poorest-quality habitat (scrub) or near the inland colony edge and the colony area did not shrink. In agreement with predictions, penguins shifted from nests with less cover to nests with more cover. The highest nest densities and the steepest declines were in habitats of large bushes and bush clusters. As the population declined penguins abandoned nests on the edges of large bushes. Constraints on penguin habitat-use changes include strong area and nest-site fidelity, increased avian predation in high-density areas, soil characteristics, and the costs of making and maintaining nests. Contrary to conventional wisdom we found low-density, poor-quality scrub habitat (which covers >70 % of the colony area) contained 45 % of active nests, produced 44 % of fledglings, and was as important as high-quality habitat for reproductive output. Our research shows that all habitats in a declining colony of seabirds have value for conservation.