1,004 research outputs found

    Oviposition sequence of non-pollinating fig wasps associated with Ficus benjamina in China

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    Fig-fig wasp mutualisms are exploited by non-pollinating fig wasps (NPFWs). In most cases, NPFWs oviposit into ovaries of female flowers from outside syconia. In this study, the oviposition sequence of externally ovipositing non-pollinating fig wasps associated with Ficus benjamina were studied by direct observation, yellow sticky board and manipulation experiments in Xishuangbanna, southwest of China. The results showed that (i) Different genera of wasps showed a temporal partition in oviposition sequence among NPFWs. Acophila, Sycobia and Walkerella wasps colonized syconia in pre-female phase, while Micronisa, Philotrypesis and Sycoscapter oviposited in the interfloral phase. Further, NPFWs of the same genus also showed difference ovposition period. (ii) Different genera of wasps exhibited various strategies of resource exploitation. Acophila, Sycobia and Walkerella wasps were gallers, while Philotrypesis wasps should be inquiline. However, only the galler species Walkerella sp.2 had significant negative effective on pollinator and seed

    Astragalus liuaiminii, a new species of Astragalus (Fabaceae) from Xinjiang, China

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    A new species, Astragalus liuaiminii Z. Z. Yang & Q. R. Liu (Fabaceae), is described and illustrated from Xinjiang Province, China. The new species is close to A. wenquanensis S. B. Ho, but differs from the latter by leaves having a single leaflet (vs. 3–5 leaflets), and inflorescences with 1–2 flowers (vs. inflorescences with 5–7 flowers). It is also similar to A. monophyllus Maxim in leaf shape, but differs by its calyx expanding to become saccate and totally enveloping the pod (vs. calyx tubular, and ruptured by pod after flowering)

    Planets Across Space and Time (PAST) IV: The Occurrence and Architecture of Kepler Planetary Systems as a Function of Kinematic Age Revealed by the LAMOST-Gaia-Kepler Sample

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    One of the fundamental questions in astronomy is how planetary systems form and evolve. Measuring the planetary occurrence and architecture as a function of time directly addresses this question. In the fourth paper of the Planets Across Space and Time (PAST) series, we investigate the occurrence and architecture of Kepler planetary systems as a function of kinematic age by using the LAMOST-Gaia-Kepler sample. To isolate the age effect, other stellar properties (e.g., metallicity) have been controlled. We find the following results. (1) The fraction of stars with Kepler-like planets (FKepF_{\text{Kep}}) is about 50% for all stars; no significant trend is found between FKepF_{\text{Kep}} and age. (2) The average planet multiplicity (Nˉp\bar{N}_p) exhibits a decreasing trend (~2σ\sigma significance) with age. It decreases from Nˉp\bar{N}_p~3 for stars younger than 1 Gyr to Nˉp\bar{N}_p~1.8 for stars about 8 Gyr. (3) The number of planets per star (η=FKep×Nˉp\eta=F_{\text{Kep}}\times\bar{N}_p) also shows a decreasing trend (~2-3σ\sigma significance). It decreases from η\eta~1.6-1.7 for young stars to η\eta~1.0 for old stars. (4) The mutual orbital inclination of the planets (σi,k\sigma_{i,k}) increases from 1.20.5+1.41.2^{+1.4}_{-0.5} to 3.52.3+8.13.5^{+8.1}_{-2.3} as stars aging from 0.5 to 8 Gyr with a best fit of logσi,k=0.2+0.4×logAge1Gyr\log{\sigma_{i,k}}=0.2+0.4\times\log{\frac{\text{Age}}{\text{1Gyr}}}. Interestingly, the Solar System also fits such a trend. The nearly independence of FKepF_{\text{Kep}}~50% on age implies that planet formation is robust and stable across the Galaxy history. The age dependence of Nˉp\bar{N}_p and σi,k\sigma_{i,k} demonstrates planetary architecture is evolving, and planetary systems generally become dynamically hotter with fewer planets as they age.Comment: 27 pages, 20 figures, 4tables, accepted for publication in A

    Planets Across Space and Time (PAST). III. Morphology of the Planetary Radius Valley as a Function of Stellar Age and Metallicity in the Galactic Context Revealed by the LAMOST-Gaia-Kepler Sample

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    The radius valley, a dip in the radius distribution of exoplanets at ~1.9 Earth radii separates compact rocky Super-Earths and Sub-Neptunes with lower density. Various hypotheses have been put forward to explain the radius valley. Characterizing the radius valley morphology and its correlation to stellar properties will provide crucial observation constraints on its origin mechanism and deepen the understanding of planet formation and evolution. In this paper, the third part of the Planets Across the Space and Time (PAST) series, using the LAMOST-Gaia-Kepler catalog, we perform a systematical investigation into how the radius valley morphology varies in the Galactic context, i.e., thin/thick galactic disks, stellar age and metallicity abundance ([Fe/H] and [alpha/Fe]). We find that (1) The valley becomes more prominent with the increase of both age and [Fe/H]. (2) The number ratio of super-Earths to sub-Neptunes monotonically increases with age but decreases with [Fe/H] and [alpha/Fe]. (3) The average radius of planets above the valley (2.1-6 Earth radii) decreases with age but increases with [Fe/H]. (4) In contrast, the average radius of planets below the valley (R < 1.7 Earth radii) is broadly independent on age and metallicity. Our results demonstrate that the valley morphology as well as the whole planetary radius distribution evolves on a long timescale of giga-years, and metallicities (not only Fe but also other metal elements, e.g., Mg, Si, Ca, Ti) play important roles in planet formation and in the long term planetary evolution.Comment: Accepted for pubilication in AJ, 20 Pages, 10 figures, 2 Tables (Appendix: 13 Figures

    Plasmon-enhanced Stimulated Raman Scattering Microscopy with Single-molecule Detection Sensitivity

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    Stimulated Raman scattering (SRS) microscopy allows for high-speed label-free chemical imaging of biomedical systems. The imaging sensitivity of SRS microscopy is limited to ~10 mM for endogenous biomolecules. Electronic pre-resonant SRS allows detection of sub-micromolar chromophores. However, label-free SRS detection of single biomolecules having extremely small Raman cross-sections (~10-30 cm2 sr-1) remains unreachable. Here, we demonstrate plasmon-enhanced stimulated Raman scattering (PESRS) microscopy with single-molecule detection sensitivity. Incorporating pico-Joule laser excitation, background subtraction, and a denoising algorithm, we obtained robust single-pixel SRS spectra exhibiting the statistics of single-molecule events. Single-molecule detection was verified by using two isotopologues of adenine. We further demonstrated the capability of applying PESRS for biological applications and utilized PESRS to map adenine released from bacteria due to starvation stress. PESRS microscopy holds the promise for ultrasensitive detection of molecular events in chemical and biomedical systems

    Identification of pyroptosis-related subtypes and establishment of prognostic model and immune characteristics in asthma

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    BackgroundAlthough studies have shown that cell pyroptosis is involved in the progression of asthma, a systematic analysis of the clinical significance of pyroptosis-related genes (PRGs) cooperating with immune cells in asthma patients is still lacking.MethodsTranscriptome sequencing datasets from patients with different disease courses were used to screen pyroptosis-related differentially expressed genes and perform biological function analysis. Clustering based on K-means unsupervised clustering method is performed to identify pyroptosis-related subtypes in asthma and explore biological functional characteristics of poorly controlled subtypes. Diagnostic markers between subtypes were screened and validated using an asthma mouse model. The infiltration of immune cells in airway epithelium was evaluated based on CIBERSORT, and the correlation between diagnostic markers and immune cells was analyzed. Finally, a risk prediction model was established and experimentally verified using differentially expressed genes between pyroptosis subtypes in combination with asthma control. The cMAP database and molecular docking were utilized to predict potential therapeutic drugs.ResultsNineteen differentially expressed PRGs and two subtypes were identified between patients with mild-to-moderate and severe asthma conditions. Significant differences were observed in asthma control and FEV1 reversibility between the two subtypes. Poor control subtypes were closely related to glucocorticoid resistance and airway remodeling. BNIP3 was identified as a diagnostic marker and associated with immune cell infiltration such as, M2 macrophages. The risk prediction model containing four genes has accurate classification efficiency and prediction value. Small molecules obtained from the cMAP database that may have therapeutic effects on asthma are mainly DPP4 inhibitors.ConclusionPyroptosis and its mediated immune phenotype are crucial in the occurrence, development, and prognosis of asthma. The predictive models and drugs developed on the basis of PRGs may provide new solutions for the management of asthma

    Evidence for a synergistic effect of post-translational modifications and genomic composition of eEF-1 alpha on the adaptation of Phytophthora infestans

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    Genetic variation plays a fundamental role in pathogen's adaptation to environmental stresses. Pathogens with low genetic variation tend to survive and proliferate more poorly due to their lack of genotypic/phenotypic polymorphisms in responding to fluctuating environments. Evolutionary theory hypothesizes that the adaptive disadvantage of genes with low genomic variation can be compensated for structural diversity of proteins through post-translation modification (PTM) but this theory is rarely tested experimentally and its implication to sustainable disease management is hardly discussed. In this study, we analyzed nucleotide characteristics of eukaryotic translation elongation factor-1 alpha (eEF-l alpha) gene from 165 Phytophthora infestans isolates and the physical and chemical properties of its derived proteins. We found a low sequence variation of eEF-l alpha protein, possibly attributable to purifying selection and a lack of intra-genic recombination rather than reduced mutation. In the only two isoforms detected by the study, the major one accounted for >95% of the pathogen collection and displayed a significantly higher fitness than the minor one. High lysine representation enhances the opportunity of the eEF-1 alpha protein to be methylated and the absence of disulfide bonds is consistent with the structural prediction showing that many disordered regions are existed in the protein. Methylation, structural disordering, and possibly other PTMs ensure the ability of the protein to modify its functions during biological, cellular and biochemical processes, and compensate for its adaptive disadvantage caused by sequence conservation. Our results indicate that PTMs may function synergistically with nucleotide codes to regulate the adaptive landscape of eEF-1 alpha, possibly as well as other housekeeping genes, in P. infestans. Compensatory evolution between pre- and post-translational phase in eEF-1 alpha could enable pathogens quickly adapting to disease management strategies while efficiently maintaining critical roles of the protein playing in biological, cellular, and biochemical activities. Implications of these results to sustainable plant disease management are discussed

    Prevalence of sexual harassment of nurses and nursing students in China: A meta-analysis of observational studies

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    Sexual harassment experienced by nurses and nursing students is common and significantly associated with negative consequences. This study is a meta-analysis of the pooled prevalence of sexual harassment of nurses and nursing students in China. Electronic databases (PubMed, EMBASE, PsycINFO, Web of Science and Ovid, China National Knowledge Internet, WanFang, SinoMed and Chinese VIP Information) were independently and systematically searched by two reviewers from their commencement date to 12 March 2018. Forty-one studies that reported the prevalence of sexual harassment were analyzed using the random-effects model. The pooled prevalence of sexual harassment was 7.5% (95% CI: 5.5%-10.1%), with 7.5% (5.5%-10.2%) in nurses and 7.2% (3.0%-16.2%) in nursing students. Subgroup analyses showed that the year of survey and sample size were significantly associated with the prevalence of sexual harassment, but not the seniority of nursing staff, department, hospital, economic region, timeframe, age, working experience or subtypes of harassment. In China, sexual harassment was found to be common in nurses and nursing students. Considering the significant negative impact of sexual harassment, effective preventive and workplace measures should be developed

    AVNP2 protects against cognitive impairments induced by C6 glioma by suppressing tumour associated inflammation in rats

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    © 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).Glioblastoma is a kind of malignant tumour and originates from the central nervous system. In the last century, some researchers and clinician have noticed that the psychosocial and neurocognitive functioning of patients with malignant gliomas can be impaired. Many clinical studies have demonstrated that part of patients, adults or children, diagnosed with glioblastoma will suffer from cognitive deficiency during their clinical course, especially in long-term survivors. Many nanoparticles (NPs) can inhibit the biological functions of tumours by modulating tumour-associated inflammation, which provokes angiogenesis and tumour growth. As one of the best antiviral nanoparticles (AVNPs), AVNP2 is the 2nd generation of AVNP2 that have been conjugated to graphite-graphene for improving physiochemical performance and reducing toxicity. AVNP2 inactivates viruses, such as the H1N1 and H5N1influenza viruses and even the SARS coronavirus, while it inhibits bacteria, such as MRSA and E. coli. As antimicrobials, nanoparticles are considered to be one of the vectors for the administration of therapeutic compounds. Yet, little is known about their potential functionalities and toxicities to the neurotoxic effects of cancer. Herein, we explored the functionality of AVNP2 on inhibiting C6 in glioma-bearing rats. The novel object-recognition test and open-field test showed that AVNP2 significantly improved the neuro-behaviour affected by C6 glioma. AVNP2 also alleviated the decline of long-term potentiation (LTP) and the decreased density of dendritic spines in the CA1 region induced by C6. Western blot assay and immunofluorescence staining showed that the expressions of synaptic-related proteins (PSD-95 and SYP) were increased, and these findings were in accordance with the results mentioned above. It revealed that the sizes of tumours in C6 glioma-bearing rats were smaller after treatment with AVNP2. The decreased expression of inflammatory factors (IL-1β, IL-6 and TNF-α) by Western blotting assay and ELISA, angiogenesis protein (VEGF) by Western blotting assay and other related proteins (BDNF, NF-ĸB, iNOS and COX-2) by Western blotting assay in peri-tumour tissue indicated that AVNP2 could control tumour-associated inflammation, thus efficiently ameliorating the local inflammatory condition and, to some extent, inhibiting angiogenesis in C6-bearing rats. In conclusion, our results suggested that AVNP2 could have an effect on the peri-tumor environment, obviously restraining the growth progress of gliomas, and eventually improving cognitive levels in C6-bearing rats.Peer reviewedProo
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