Eastern honeybee Apis cerana sense cold flowering plants by increasing the static binding affinity of odorant-binding protein to cold floral volatiles from loquats.

Eastern honeybee Apis cerana has important ecological value for the cold flowering loquat flower pollination in early winter in East Asia. However, the low-temperature adaptive pollination mechanism has not yet been revealed. One odorant-binding protein, OBP2, had been found that could bind to some plant volatiles with strong affinity before. In this study, by using competitive fluorescence binding assay, we first measured the ligand-binding profiles of recombinant OBP2 protein with nine representative aroma chemical substances from loquat flowers. Thermodynamic results showed that three loquat volatiles, 4-Methoxybenzaldehyde, (E)-Ethyl cinnamate, and Methyl cinnamate, have the strongest binding affinity with OBP2 with the static process. And interestingly their binding affinity significantly increased at low temperature (285 K/12 °C) compared to high temperature (298 K/25 °C). In addition, site-directed mutagenesis results showed that Met55 and Lys51 may be the key amino acid sites in the electrostatic and hydrophobic interactions of OBP2 interacting with Methyl cinnamate, respectively. This study suggests that OBP2 is functionally similar and universal in binding to different flower volatiles at low temperatures. Our studies interpreted a novel olfactory mechanism of A. cerana sensing loquat floral volatiles in cold early winter, and enrich a theoretical molecular basis for the temperature-adaptive ecological mechanism of insects' pollination.

Unique dynamic mode between Artepillin C and human serum albumin implies the characteristics of Brazilian green propolis representative bioactive component.

As a representative bioactive component in Brazil green propolis, Artepillin C (ArtC; 3, 5-diprenyl-4-hydroxycinnamic acid) has been reported a wide variety of physiological activities including anti-tumor, anti-inflammatory, and antimicrobial activity etc. However, it seems incompatible that ArtC in vivo was characterized as low absorption efficiency and low bioavailability. In order to obtain the elucidation, we further investigated the physicochemical basis of ArtC interacting with human serum albumin (HSA) in vitro. We found a unique dynamic mode interaction between ArtC and HSA, which is completely different from other reported propolis bioactive components. Thermodynamic analysis showed that hydrophobic interactions and electrostatic forces are the main driving force. The competitive assay indicates that the binding site of ArtC with HSA is close to the Sudlow's site I. The findings of this study reveal the unique physicochemical transport mechanism of ArtC in the human body, which helps to further understand the uniqueness of the representative functional components of Brazilian green propolis in the human body.

Chemical structure of semiochemicals and key binding sites together determine the olfactory functional modes of odorant-binding protein 2 in Eastern honey bee, Apis cerana.

Insects can exhibit flexible olfaction that is sensitive to complex natural chemical environments. Odorant-binding proteins (OBPs) in insects' antennal chemosensilla can act as transporters of plant volatiles and pheromones across the sensillar lymph. Although the physiological functions of OBPs have been widely reported, it is still unclear how OBP binds to ligands with various structures in detail. Here, we further investigated the ligand-binding modes and characteristics of AcerOBP2 from the Eastern honey bee (Apis cerana). The results showed that, as a specific protein distributed below the base of chemosensilla on the antennal surface, AcerOBP2 was strongly bound with the candidate floral volatiles and bee pheromones. By docking analysis and site-directed mutagenesis, four different binding modes were found in the five AcerOBP2 mutants between six ligands. Two key amino acids, Ser123 and Lys51, play a key role in AcerOBP2 binding to odors, depending on the presence or absence of hydrogen bonds. In addition, the binding modes depend on their chemical structures and the binding poses of the diverse ligands. These results not only further prompted the functional basis of the relationship between the chemical structures of odorants and bee OBPs, but also revealed the complexity of the flexible behavioral modes of odor binding in insect olfactory systems.

Survey of the acceptance status of HPV self-sampling screening in female population for cervical cancer / 中华妇产科杂志

Objective To investigate the acceptance of HPV self-sampling mode in cervical cancer screening population and explore its feasibility. Methods From March 5 to 15, 2018, researchers investigated women who participated in cervical cancer screening organized by Beijing Shunyi Women＇s and Children＇s Hospital in the form of questionnaires. Questionnaires were conducted on their acceptance status and the factors that affect the self-sampling experience. The specific contents of the questionnaires were as follows: (1) the experience of using self-sampling included operability, comfortable, sample time-consuming, bleeding or not after sampling; (2) psychological changes after self-sampling, including the willingness to accept self-sampling again, the worrying problems during self-sampling process. According to whether or not have operating video guidance, the self-sampling experience and psychological changes after self-sampling were compared. Results (1) There were 1 375 women participated in the questionnaire survey, and 86.55% (1 190/1 375) of them thought the self-sampling was convenient, 78.40% (1 078/1 375) thought it was not uncomfortable, 88.58% (1 218/1 375) thought the sampling time was fast (less than 5 minutes), 94.04% (1 293/1 375) self-sampling without bleeding; and 83.27% (1 145/1 375) were willing to self-sampling for cervical cancer screening again, 85.82% (1 180/1 375) were afraid of inaccurate sampling. (2) Among the 1 375 women, 1 202 were in the video guidance group and 173 were in the non-guidance group. The self-sampling experience of women in video guidance group was better than those of non-guidance group in operability, comfortable, sampling time-consuming and bleeding after sampling. The proportion of women who willing to self-sampling again was higher than that of non-guidance group (86.69% vs 59.54%, respectively). The proportion of women who worried operating incorrectly was lower than that of non-guidance group (11.23% vs 32.37%, respectively). The differences were significant (all P<0.05). Conclusions Self-sampling for HPV testing in cervical cancer screening is easy to operate and has little discomfort complaint. It is feasible in cervical cancer screening. Operational video guidance during the screening process could effectively improve the women＇s experience and willingness to self-sampling again in the future.

The study on the association of long-term ambient fine particulate matters exposure and elevated blood pressure in children / 中华预防医学杂志

Objective@#To evaluate the association of long-term ambient fine particulate matters (PM2.5) exposure with elevated blood pressure in children.@*Methods@#From April 2012 to June 2013, we used cluster randomized sampling method to investigate 9 354 children aged 5-17 years old from 68 primary and middle schools in the seven Northeastern Cities (Shenyang, Dalian, Fushun, Anshan, Benxi, Liaoyang and Dandong) in Liaoning Province, and measured their blood pressure (BP). A spatial statistical model nested by aerosol optical depth (AOD) was used to inverse PM2.5 concentrations. Generalized additive model was used to quantify the association between PM2.5 exposure and blood pressure in children. To examine the associations, two-level regression model was used to evaluate individual characteristics′ modifying effect on the health influence of PM2.5.@*Results@#The prevalence of hypertension in children was 13.78% (1 289/9 354). The results showed that there was an associations between hypertension and pollutants, and the multivariable regression analysis indicated that the increase in mean systolic blood pressure (SBP), diastolic blood pressure (DBP), and the OR of hypertension associated with a 10 μg/m3 increase for PM2.5 were 3.12 (95%CI: 2.71-3.54) mmHg (1 mmHg=0.133 kPa), 1.45 (95%CI:1.12-1.78) mmHg, and 1.55 (95%CI: 1.10-2.19), respectively. Compared with non-breastfeeding children (OR=2.10, 95%CI: 1.39-3.17), children who were breastfeeding (OR=1.49, 95%CI: 1.00-2.20) exhibited consistently weaker effects, and the interaction effect of P value was 0.002.@*Conclusion@#Study findings indicate that long-term exposure to PM2.5 is associated with increased arterial BP and hypertension among the children. Breastfeeding may reduce this association.

Physicochemical Basis and Comparison of Two Type II Sex Pheromone Components Binding with Pheromone-Binding Protein 2 from Tea Geometrid, Ectropis obliqua.

Lepidopteran geometrid moth can produce complex Type II sex pheromone components to attract males and trigger mating behavior. Although several sex pheromone components have been identified, it remains unclear whether their physicochemical roles in sex pheromone sensing are the same. Therefore, we utilized tea geometrid ( Ectropis obliqua) as an example model to investigate and compare the physicochemical basis of two key Type II sex pheromone components, cis-6,7-epoxy-(3Z,9Z)-3,9-octadecadiene ( Z3 Z9-6,7-epo-18:Hy) and ( Z, Z, Z)-3,6,9-octadecatriene (Z3Z6Z9-18:Hy), interacting with pheromone-binding protein 2 ( EoblPBP2) from E. obliqua. Multispectral, thermodynamic, docking, and site-directed mutagenesis indicated that the major sex pheromone component Z3Z9-6,7-epo-18:Hy is more susceptible to pH-tuned than the minor component Z3Z6Z9-18:Hy, whereas Z3Z6Z9-18:Hy seems to be more susceptible to temperature and amino acid mutations than Z3Z9-6,7-epo-18:Hy. Our study suggests that different components of Type II sex pheromone play different binding characters under specific conditions in the physicochemical behavior. This deeply supplements the theoretical knowledge of Type II pheromones involved in the recognition and discrimination in the Lepidopteran sex pheromones family.

Schaftoside Interacts With NlCDK1 Protein: A Mechanism of Rice Resistance to Brown Planthopper, Nilaparvata lugens.

Brown planthopper (BPH) Nilaparvata lugens Stål is a serious insect pest of rice in Asian countries. Active compounds have close relationship with rice resistance against BPH. In this study, HPLC, MS/MS, and NMR techniques were used to identify active compounds in total flavonoids of rice. As a result, a BPH resistance-associated compound, Peak 1 in HPLC chromatogram of rice flavonoids, was isolated and identified as schaftoside. Feeding experiment with artificial diet indicated that schaftoside played its role in a dose dependent manner, under the concentration of 0.10 and 0.15 mg mL-1, schaftoside showed a significant inhibitory effect on BPH survival (p < 0.05), in comparison with the control. The fluorescent spectra showed that schaftoside has a strong ability to bind with NlCDK1, a CDK1 kinase of BPH. The apparent association constant KA for NlCDK1 binding with schaftoside is 6.436 × 103 L/mol. Docking model suggested that binding of schaftoside might affect the activation of NlCDK1 as a protein kinase, mainly through interacting with amino acid residues Glu12, Thr14 and Val17 in the ATP binding element GXGXXGXV (Gly11 to Val18). Western blot using anti-phospho-CDK1 (pThr14) antibody confirmed that schaftoside treatment suppressed the phosphorylation on Thr-14 site of NlCDK1, thus inhibited its activation as a kinase. Therefore, this study revealed the schaftoside-NlCDK1 interaction mode, and unraveled a novel mechanism of rice resistance against BPH.

Various Bee Pheromones Binding Affinity, Exclusive Chemosensillar Localization, and Key Amino Acid Sites Reveal the Distinctive Characteristics of Odorant-Binding Protein 11 in the Eastern Honey Bee, Apis cerana.

Odorant-binding proteins (OBPs) are the critical elements responsible for binding and transporting odors and pheromones in the sensitive olfactory system in insects. Honey bees are representative social insects that have complex odorants and pheromone communication systems relative to solitary insects. Here, we first cloned and characterized OBP11 (AcerOBP11), from the worker bees antennae of Eastern honey bee, Apis cerana. Based on sequence and phylogenetic analysis, most sequences homologous to AcerOBP11 belong to the typical OBPs family. The transcriptional expression profiles showed that AcerOBP11 was expressed throughout the developmental stages and highly specifically expressed in adult antennae. Using immunofluorescence localization, AcerOBP11 in worker bee's antennae was only localized in the sensilla basiconica (SB) near the fringe of each segment. Fluorescence ligand-binding assay showed that AcerOBP11 protein had strong binding affinity with the tested various bee pheromones components, including the main queen mandibular pheromones (QMPs), methyl p-hydroxybenzoate (HOB), and (E)-9-oxo-2-decanoic acid (9-ODA), alarm pheromone (n-hexanol), and worker pheromone components. AcerOBP11 also had strong binding affinity to plant volatiles, such as 4-Allylveratrole. Based on the docking and site-directed mutagenesis, two key amino acid residues (Ile97 and Ile140) were involved in the binding of AcerOBP11 to various bee pheromones. Taken together, we identified that AcerOBP11 was localized in a single type of antennal chemosensilla and had complex ligand-binding properties, which confer the dual-role with the primary characteristics of sensing various bee pheromones and secondary characteristics of sensing general odorants. This study not only prompts the theoretical basis of OBPs-mediated bee pheromones recognition of honey bee, but also extends the understanding of differences in pheromone communication between social and solitary insects.

Neurons in the hippocampus of chemobrain versus non-chemotherapy brain / 中国组织工程研究

BACKGROUND:Chemotherapy drugs have been shown to penetrate the blood-brain barrier and cause neurotoxicity,further damaging nerve cells.OBEJCTIVE:To investigate the changes in the expression and morphology of hippocampal neurons in chemobrain,and to investigate the underlying mechanism of nerve regeneration in chemobrain.METHODS:The brain specimens were obtained from the six patients undergoing cancer chemotherapy and six patients without chemotherapy,and were then subdivided into two groups:＜ 60 years and ＞ 60 years groups (n=3 per group).Immunofluorescence staining with specific antibodies was used to detect the changes in the morphology and number of neurons in the hippocampus CA1,CA2 and CA3.RESULTS AND CONCLUSION:The number of neurons positive for NeuN,DCX and PV in the hippocampal CA1,CA2 and CA3 in the chemotherapy group was significantly lower than that in the non-chemotherapy group.Moreover,the neurons positive for PV were smaller,with less and shorter nervous processes.Immunofiuorescence staining findings showed that the ＜ 60 years old patients in the chemotherapy group had less neurons positive for NeuN and DCX than that in the non-chemotherapy;for ＞ 60 years old patients,there was no significant difference between two groups.These findings suggest that chemotherapy can downregulate the expression of immature neurons in the hippocampus and reduce the number of neurons in the hippocampus.Moreover,chemotherapy can change the morphology and reduce the number of PV neurons.

Application of Diffusion Tensor Imaging in Stroke Rehabilitation (review) / 中国康复理论与实践

@# Diffusion tensor imaging is a non-invasive MRI technique which can identify changes of cerebral microstructure that CT and MRI is difficult to find, especially in the change of nerve fibers direction, which can be used for the researches of evaluation, recovery mechanism and prognosis of neurology. It has been applied in rehabilitation of motor, language and recognition of post-stroke patients.

Diffuse reflections by randomly gradient index metamaterials.

We have demonstrated that a thin planar coating with randomly distributed index gradients can create diffuse reflections in front of a planar conducting sheet. This scheme is verified by two-dimensional near-field scanning measurement, in which the randomly gradient index coating is implemented by periodic crossed-I-shaped array whose unit cell's dimension varies spatially. Some qualitative principles of choosing the distribution mode of random index gradient are presented.

Compact-sized and broadband carpet cloak and free-space cloak.

Recently, invisible cloaks have attracted much attention due to their exciting property of invisibility, which are based on a solid theory of transformation optics and quasi-conformal mapping. Two kinds of cloaks have been proposed: free-space cloaks, which can render objects in free space invisible to incident radiation, and carpet cloaks (or ground-plane cloaks), which can hide objects under the conducting ground. The first free-space and carpet cloaks were realized in the microwave frequencies using metamaterials. The free-space cloak was composed of resonant metamaterials, and hence had restriction of narrow bandwidth and high loss; the carpet cloak was made of non-resonant metamaterials, which have broad bandwidth and low loss. However, the carpet cloak has a severe restriction of large size compared to the cloaked object. The above restrictions become the bottlenecks to the real applications of free-space and carpet cloaks. Here we report the first experimental demonstration of broadband and low-loss directive free-space cloak and compact-sized carpet cloak based on a recent theoretical study. Both cloaks are realized using non-resonant metamaterials in the microwave frequency, and good invisibility properties have been observed in experiments. This approach represents a major step towards the real applications of invisibility cloaks.

Arbitrary bending of electromagnetic waves using realizable inhomogeneous and anisotropic materials.

We propose an optical transformation to bend electromagnetic waves by designing proper inhomogeneous and anisotropic materials, which are hereinafter referred to as metamaterials (MTMs). When the waveguide bends are filled with MTMs, the incident waves will pass through the bends without any reflections (for full-parameter MTMs) or with very small reflections (for simplified-parameter MTMs). When MTMs are placed in air, the incident waves will be bent to any designed directions. We also discuss the wave bending using layered homogeneous uniaxial MTMs, which can be easily realized using artificial structures.