Visual modelling suggests a weak relationship between the evolution of ultraviolet vision and plumage coloration in birds

Birds have sophisticated colour vision mediated by four cone types that cover a wide visual spectrum including ultraviolet (UV) wavelengths. Many birds have modest UV sensitivity provided by violet‐sensitive (VS) cones with sensitivity maxima between 400 and 425 nm. However, some birds have evolved higher UV sensitivity and a larger visual spectrum given by UV‐sensitive (UVS) cones maximally sensitive at 360–370 nm. The reasons for VS–UVS transitions and their relationship to visual ecology remain unclear. It has been hypothesized that the evolution of UVS‐cone vision is linked to plumage colours so that visual sensitivity and feather coloration are ‘matched’. This leads to the specific prediction that UVS‐cone vision enhances the discrimination of plumage colours of UVS birds while such an advantage is absent or less pronounced for VS‐bird coloration. We test this hypothesis using knowledge of the complex distribution of UVS cones among birds combined with mathematical modelling of colour discrimination during different viewing conditions. We find no support for the hypothesis, which, combined with previous studies, suggests only a weak relationship between UVS‐cone vision and plumage colour evolution. Instead, we suggest that UVS‐cone vision generally favours colour discrimination, which creates a nonspecific selection pressure for the evolution of UVS cones.     

Temperature sensitivity of spring vegetation phenology correlates to within-spring warming speed over the Northern Hemisphere

The inter-annual shift of spring vegetation phenology relative to per unit change of preseason temperature, referred to as temperature sensitivity (days °C⁻¹), quantifies the response of spring phenology to temperature change. Temperature sensitivity was found to differ greatly among vegetation from different environmental conditions. Understanding the large-scale spatial pattern of temperature sensitivity and its underlying determinant will greatly improve our ability to predict spring phenology. In this study, we investigated the temperature sensitivity for natural ecosystems over the North Hemisphere (north of 30°N), based on the vegetation phenological date estimated from NDVI time-series data provided by the Advanced Very High Resolution Radiometer (AVHRR) and the corresponding climate dataset. We found a notable longitudinal change pattern with considerable increases of temperature sensitivity from inlands to most coastal areas and a less obvious latitudinal pattern with larger sensitivity in low latitude area. This general spatial variation in temperature sensitivity is most strongly associated with the within-spring warming speed (WWS; r = 0.35, p < 0.01), a variable describing the increase speed of daily mean temperature during spring within a year, compared with other factors including the mean spring temperature, spring precipitation and mean winter temperature. These findings suggest that the same magnitude of warming will less affect spring vegetation phenology in regions with higher WWS, which might partially reflect plants’ adaption to local climate that prevents plants from frost risk caused by the advance of spring phenology. WWS accounts for the spatial variation in temperature sensitivity and should be taken into account in forecasting spring phenology and in assessing carbon cycle under the projected climate warming.     

BP人工神经网络模拟杨树林冠蒸腾

利用2008和2010年的气温、饱和差、总辐射和叶面积指数作为模型输入,液流法观测的蒸腾速率作为模型输出,建立了用于杨树林冠蒸腾模拟的BP人工神经网络模型,利用2009年的观测数据对模型的模拟能力进行了检验,并应用连接权值计算得到的输入变量对输出变量的相对贡献进行了敏感性分析。结果表明:建立的BP人工神经网络蒸腾模型可以很好的模拟林冠蒸腾大小和季节变化,模拟的绝对误差和绝对相对误差的平均值分别为0.11 mm/d和9.5%,纳什效率系数为0.83;输入变量对蒸腾的相对贡献以及蒸腾与输入变量之间的相关性大小顺序相同,均为总辐射叶面积指数饱和差气温。     

Predation Risk Drives Habitat‐Specific Sex Ratio in a Monomorphic Species,the Brown Hare (Lepus europaeus)

In dimorphic species, sexual habitat segregation is generally explained by the differences in nutritional needs or by a trade‐off between fulfilling food requirements and avoiding predation. However, it remains unclear whether predation risk is strong enough to drive the differences in habitat use between sexes as predicted by the predation sensitivity hypothesis. Here we test in a monomorphic species, the brown hare (Lepus europaeus), the prediction that abundance of the gender more sensitive to predation is higher in safer habitat. We used data on 1645 individually marked hares in western Poland during autumn–winter seasons of 1966/1967–1978/1979 to estimate sex‐specific annual survival rates. We analyzed the stomach contents of 134 foxes shot in 1965/1966–1994/1995 to evaluate fox predation on hares. Finally, we employed data on 26 790 hares live‐trapped in 1965/1966–1994/1995 to analyze hare sex ratio across habitats. We found that male annual survival rate was lower than that of females and that the predation risk by foxes on hares was lower in agricultural than forest habitat. Our finding, that males were more often trapped by nets in agricultural than the forest habitat, provides indirect evidence for the predation sensitivity hypothesis. We conclude that predation risk can be a driving force for habitat‐specific sex ratio in a monomorphic species such as the brown hare.     

Short-term nitrogen fertilization decreased root and microbial respiration in a young Cunninghamia lanceolata plantation

Aims As the primary pathway for CO₂ emission from terrestrial ecosystems to the atmosphere, soil respiration is estimated to be 80 Pg C·a^-1 to 100 Pg C·a^-1, equivalent to 10 fold of fossil fuel emissions. As an important management practice in plantation forests, fertilization does not only increase primary production but also affects soil respiration. To investigate how nitrogen (N) fertilization affects total soil, root and microbial respiration, a N fertilization experiment was conducted in a five-year-old Cunninghamia lanceolata plantation in Huitong, Hunan Province, located in the subtropical region. MethodsOne year after fertilization, soil respiration was monitored monthly by LI-8100 from July 2013 to June 2014. Soil temperature and water content (0-5 cm soil depth) were also measured simultaneously. Available soil nutrients, fine root biomass and microbial communities were analyzed in June 2013. Important findings Total soil, root and microbial respiration rates were 22.7%, 19.6%, and 23.5% lower in the fertilized plots than in the unfertilized plots, respectively. The temperature sensitivity (Q₁₀) of soil respiration ranged from 1.81 to 2.04, and the Q₁₀ value of microbial respiration decreased from 2.04 in the unfertilized plots to 1.84 in the fertilized plots. However, neither the Q₁₀ value nor the patterns of total soil respiration were affected by N fertilization. In the two-factor model, soil temperature and moisture accounted for 69.9%-79.7% of the seasonal variations in soil respiration. These results suggest that N fertilization reduces the response of soil organic carbon decomposition to temperature change and may contribute to the increase of soil carbon storage under global warming in subtropical plantations.     

Noninvasive cross‐sectional imaging of proximal caries using swept‐source optical coherence tomography (SS‐OCT) in vivo

The aim of this study was to determine the diagnostic accuracy of swept‐source optical coherent tomography (SS‐OCT) in detecting and estimating the depth of proximal caries in posterior teeth in vivo. SS‐OCT images and bitewing radiographs were obtained from 86 proximal surfaces of 53 patients. Six examiners scored the locations according to a caries lesion depth scale (0–4) using SS‐OCT and the radiographs. The results were compared with clinical observations obtained after the treatment. SS‐OCT could detect the presence of proximal caries in tomograms that were synthesized based on the backscatter signal obtained from the proximal carious lesion through occlusal enamel. SS‐OCT showed significantly higher sensitivity and larger area under the receiver operating characteristic curve than radiographs for the detection of cavitated enamel lesions and dentin caries (Student's t ‐test, p < 0.05). SS‐OCT appears to be a more reliable and accurate method than bitewing radiographs for the detection and estimation of the depth of proximal lesions in the clinical environment. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Variants in the 1q21 risk region are associated with a visual endophenotype of autism and schizophrenia

Deficits in sensitivity to visual stimuli of low spatial frequency and high temporal frequency (so‐called frequency‐doubled gratings) have been demonstrated both in schizophrenia and in autism spectrum disorder (ASD). Such basic perceptual functions are ideal candidates for molecular genetic study, because the underlying neural mechanisms are well characterized; but they have sometimes been overlooked in favor of cognitive and neurophysiological endophenotypes, for which neural substrates are often unknown. Here, we report a genome‐wide association study of a basic visual endophenotype associated with psychological disorder. Sensitivity to frequency‐doubled gratings was measured in 1060 healthy young adults, and analyzed for association with genotype using linear regression at 642 758 single nucleotide polymorphism (SNP) markers. A significant association (P = 7.9 × 10^?9) was found with the SNP marker rs1797052, situated in the 5′‐untranslated region of PDZK1; each additional copy of the minor allele was associated with an increase in sensitivity equivalent to more than half a standard deviation. A permutation procedure, which accounts for multiple testing, showed that the association was significant at the α = 0.005 level. The region on chromosome 1q21.1 surrounding PDZK1 is an established susceptibility locus both for schizophrenia and for ASD, mirroring the common association of the visual endophenotype with the two disorders. PDZK1 interacts with N‐methyl‐d ‐aspartate receptors and neuroligins, which have been implicated in the etiologies of schizophrenia and ASD. These findings suggest that perceptual abnormalities observed in two different disorders may be linked by common genetic elements .     

The eIF2&alpha; kinases inhibit vesicular stomatitis virus replication independently of eIF2 phosphorylation.

The eIF2alpha kinases have been involved in the inhibition of vesicular virus replication but the contribution of each kinase to this process has not been fully investigated. Using mouse embryonic fibroblasts (MEFs) from knock-out mice we show that PKR and HRI have no effects on VSV replication as opposed to PERK and GCN2, which exhibit strong inhibitory effects. When MEFs containing the serine 51 to alanine mutation of eIF2alpha were used, we found that VSV replication is independent of eIF2alpha phosphorylation. Nevertheless, the kinase domain of the eIF2alpha kinases is both necessary and sufficient to inhibit VSV replication in cultured cells. Induction of PI3K-Akt/PKB pathway by eIF2alpha kinase activation plays no role in the inhibition of VSV replication. Our data provide strong evidence that VSV replication is not affected by eIF2alpha phosphorylation or downstream effector pathways such as the PI3K-Akt/PKB pathway. Thus, the anti-viral properties of eIF2alpha kinases are not always related to their inhibitory effects on host protein synthesis as previously thought and are possibly mediated by phosphorylation of proteins other than eIF2alpha.     

Ectopic NGAL expression can alter sensitivity of breast cancer cells to EGFR,Bcl-2, CaM-K inhibitors and the plant natural product berberine

Neutrophil gelatinase-associated lipocalin (NGAL, a.k.a Lnc2) is a member of the lipocalin family and has diverse roles. NGAL can stabilize matrix metalloproteinase-9 from autodegradation. NGAL is considered as a siderocalin that is important in the transport of iron. NGAL expression has also been associated with certain neoplasias and is implicated in the metastasis of breast cancer. In a previous study, we examined whether ectopic NGAL expression would alter the sensitivity of breast epithelial, breast and colorectal cancer cells to the effects of the chemotherapeutic drug doxorubicin. While abundant NGAL expression was detected in all the cells infected with a retrovirus encoding NGAL, this expression did not alter the sensitivity of these cells to doxorubicin as compared with empty vector-transduced cells. We were also interested in determining the effects of ectopic NGAL expression on the sensitivity to small-molecule inhibitors targeting key signaling molecules. Ectopic NGAL expression increased the sensitivity of MCF-7 breast cancer cells to EGFR, Bcl-2 and calmodulin kinase inhibitors as well as the natural plant product berberine. Furthermore, when suboptimal concentrations of certain inhibitors were combined with doxorubicin, a reduction in the doxorubicin IC₅₀ was frequently observed. An exception was observed when doxorubicin was combined with rapamycin, as doxorubicin suppressed the sensitivity of the NGAL-transduced MCF-7 cells to rapamycin when compared with the empty vector controls. In contrast, changes in the sensitivities of the NGAL-transduced HT-29 colorectal cancer cell line and the breast epithelial MCF-10A cell line were not detected compared with empty vector-transduced cells. Doxorubicin-resistant MCF-7/Dox^R cells were examined in these experiments as a control drug-resistant line; it displayed increased sensitivity to EGFR and Bcl-2 inhibitors compared with empty vector transduced MCF-7 cells. These results indicate that NGAL expression can alter the sensitivity of certain cancer cells to small-molecule inhibitors, suggesting that patients whose tumors exhibit elevated NGAL expression or have become drug-resistant may display altered responses to certain small-molecule inhibitors.     

Predicting therapy response in live tumor cells isolated with the flexible micro spring array device

Cells disseminated from primary epithelial tumors into peripheral blood, called circulating tumor cells (CTCs), can be monitored to assess metastases and to provide a surrogate marker of treatment response. Here, we demonstrate how the flexible micro spring array (FMSA) device—a novel microfluidic device that enriches CTCs by two physical parameters: size and deformability—could be used in the rational development of treatment intervention and as a method to study the fundamental biology of CTCs. Cancer cells of different origins were spiked into healthy samples of donor blood to mimic blood samples of metastatic cancer patients. This spiked human blood was filtered using the FMSA device, and the recovered cells were successfully expanded in vitro and in a novel in vivo system. A series of experiments were performed to characterize these cells and to investigate the effect of chemotherapy on the resulting cultures. As few as 20 colon cancer cells in 7.5 mL blood could be isolated with the FMSA device, expanded both in vitro and in vivo and used at 25 cells per well to obtain significant and reliable chemosensitivity data. We also show that isolating a low number of viable patient CTCs and maintaining them in culture for a few weeks is possible. The isolation of viable cancer cells from human blood using the FMSA device provides a novel and realistic means for studying the biology of viable CTCs and for testing drug efficacy on these rare cells—a hypothesis that can be tested in future clinical trials.