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1. chinaXiv:201703.01054 [pdf]

Impaired spinal glucocorticoid receptor signaling contributes to the attenuating effect of depression on mechanical allodynia and thermal hyperalgesia in rats with neuropathic pain

Wei, Xiao; Sun, Yuqi; Luo, Fei
分类: 生物学 >> 神经生物学

Although depression-induced altered pain perception has been described in several laboratory and clinical studies, its neurobiological mechanism in the central nervous system, particularly in the spinal dorsal horn remains unclear. In this study, we therefore aimed to clarify whether nociceptive sensitivity of neuropathic pain is altered in the olfactory bulbectomy (OB) model of depression and whether glucocorticoid receptor (GR), which is involved in the etio-pathologic mechanisms of both major depression and neuropathic pain, contributes to these processes in the spinal dorsal horn of male Sprague-Dawley rats. The results showed that mechanical allodynia and thermal hyperalgesia induced by spinal nerve ligation (SNL) were attenuated in OB-SNL rats with decreased spinal GR expression and nuclear translocation, while NOB (non-olfactory bulbectomy)-SNL rats showed an increased spinal GR nuclear translocation. Decreased GR nuclear translocation with normal mechanical nociception and hypoalgesia of thermal nociception were observed in OB-Sham rats, too. Intrathecal injection of GR agonist dexamethasone (4 µg / rat / day for 1 week) eliminated the attenuating effect of depression on the nociceptive hypersensitivity in OB-SNL rats and aggravated neuropathic pain in NOB-SNL rats, associating with the up-regulation of BDNF, TrkB and NR2B expression in the spinal dorsal horn. The present study shows that depression attenuates the mechanical allodynia and thermal hyperalgesia of neuropathic pain and suggests that altered spinal GR-BDNF-TrkB signaling may be one of the reasons for depression-induced hypoalgesia.

提交时间: 2017年07月24日 点击量:149, 下载量:102

2. chinaXiv:201707.00579 [pdf]

长萼兰花蕉(Orchidantha chinensis T. L. Wu var. longisepala (D. Fang) T. L. Wu)的繁育系统研究

徐凯; 崔长杰; 邹璞; 叶育石; 廖景平; 匡延凤; 刘焕芳
分类: 生物学 >> 植物学

通过野外观察、杂交指数(OCI)、花粉/胚珠比(P/O)、人工授粉、等方法,对长萼兰花蕉(Orchidantha chinensis T. L. Wu var. longisepala (D. Fang) T. L. Wu)种群的繁育系统进行了研究,并采用常规石蜡切片与扫描电子显微镜(SEM)观察了柱头与“V”形黏盘的结构与形态。结果表明:该种单花花期一般为18d,依其花部形态的变化可分为5个时期:(1)蕾期;(2)花萼未反转期;(3)花萼反转期;(4)唇瓣枯萎期;(5)花萼枯萎期。由于杂交指数(OCI)值为4,P/O值为253.89±21.09,结合人工异花授粉结实率分别为45%、75%,可以确定长萼兰花蕉属于异交,传粉过程需要传粉者;石蜡切片结果观察到长萼兰花蕉黏盘区与柱头可授区之间是光滑的表皮细胞,根据人工授粉实验与分泌物含糖量测定结果,表明长萼兰花蕉的“V”形黏盘不具有可授性,其作用可能是分泌粘液附着在传粉者背部使其便于携带花粉。长萼兰花蕉整个花期周围环境湿冷、多雨,且开花同步性较低,这些因素很可能造成了其有效传粉媒介的缺乏,影响了传粉成功,在有性繁殖受到限制时,通过根状茎进行的无性繁殖是其分布范围狭窄的主要原因。

提交时间: 2017年07月20日 点击量:45, 下载量:25

3. chinaXiv:201707.00514 [pdf]

Transcriptome analysis of Hamelia patens (Rubiaceae) anthers reveals candidate genes for tapetum and pollen wall development

Yue, Lin; Twell, David; Kuang, Yanfeng; Liao, Jingping; Zhou, Xianqiang
分类: 生物学 >> 植物学

Studies of the anther transcriptome on non-model plants without a known genome are surprisingly scarce. RNA-Seq and digital gene expression (DGE) profiling provides a comprehensive approach to identify candidate genes contributing to developmental processes in non-model species. Here we built a transcriptome library of developing anthers of Hamelia patens and analysed DGE profiles from each stage to identify genes that regulate tapetum and pollen development. In total 7,720 putative differentially expressed genes across four anther stages were identified. The number of putative stage-specific genes was: 776 at microspore mother cell stage (MMC), 807 at tetrad stage (TET), 322 at uninucleate microspore stage (UNM) and the highest number (1,864) at bicellular pollen stage (BCP). GO enrichment analysis revealed 243 differentially expressed and 108 stage-specific genes that are potentially related to tapetum development, sporopollenin synthesis and pollen wall. The number of expressed genes, their function and expression profiles were all significantly correlated with anther developmental processes. Overall comparisons of anther and pollen transcriptomes with those of rice and Arabidopsis together with the expression profiles of homologs of known anther-expressed genes, revealed conserved patterns and also divergence. The divergence may reflect taxon-specific differences in gene expression, the use RNA-seq as a more sensitive methodology, variation in tissue composition and sampling strategies. Given the lack of genomic sequence, this study succeeded in assigning putative identity to a significant proportion of anther-expressed genes and genes relevant to tapetum and pollen development in H. patens. The anther transcriptome revealed a molecular distinction between developmental stages, serving as a resource to unravel the functions of genes involved in anther development in H. patens and informing the analysis of other members of the Rubiaceae.

提交时间: 2017年07月18日 点击量:132, 下载量:55

4. chinaXiv:201707.00510 [pdf]

Soil wetting decreases the level of apparent activation energy for microbial respiration in subtropical forest ecosystems

Hao, Guangcun; Zhao, Weiping; Zhuang, Qianlai; Wei, Hui; Zhu, Qing; Liu, Yaling; Shen, Weijun
分类: 生物学 >> 生态学

Apparent activation energy (Ea) is one of the most important and sensitive parameters that control soil organic C (SOC) decomposition in prevailing earth system models (ESMs). The variation of apparent Ea is affected by multiple soil environmental factors, among which soil moisture exerts a strong effect. Aiming to better inform temperature sensitivity parameterization in ESMs, here we examined the relationship between apparent Ea and soil moisture with both incubation experiment and field measurement in subtropical forests. We found that apparent Ea declined as soil moisture increased, consistently in both incubation and field experiments. We speculated that this phenomenon was due to altered microbial community composition from changing soil moisture. Our results suggest that future warming and changing precipitation would significantly affect the decomposition of recalcitrant carbon pools in subtropical forests. Lacking representation of the impact of soil moisture on SOC decomposition temperature sensitivity in current ESMs might have biased climate projection.

提交时间: 2017年07月18日 点击量:124, 下载量:40

5. chinaXiv:201707.00474 [pdf]

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydro-anhydrocycloheximides

Yang, Li; Wu, Ping; Xue, Jinghua; Tan, Huitong; Zhang, Zheng; Wei, Xiaoyi
分类: 生物学 >> 植物学

Three new cycloheximide congeners, 2,3-dehydro--epi-isocycloheximide (1), (E)- and (Z)-2,3-dehydro-anhydrocycloheximides (2 and 3), together with three known compounds, anhydroisoheximide (4), cycloheximide (5), and isocycloheximide (6), were obtained from the cultures of Streptomyces sp. SC0581. Their structures were elucidated by extensive spectroscopic analysis in combination with theoretical conformational analysis and ECD computations. The photoinduced interconversion between 2 and 3 was observed and verified and the possible reaction path and mechanism were proposed by theoretical computations. The antifungal and cytotoxic activities of 1–6 were evaluated and suggested that 2,3-dehydrogenation results in the loss of the activities and supported the OH- is important to the activities of cycloheximide congeners.

提交时间: 2017年07月14日 点击量:100, 下载量:50

6. chinaXiv:201707.00468 [pdf]

Studies on pollen morphology of selected species of Annonaceae from Thailand

Shao, Yunyun; Xu, Fengxia
分类: 生物学 >> 植物学

The pollen morphology of 48 species and two varieties, representing 18 genera of the family Annonaceae from Thailand, is described and illustrated based on observations with scanning electron microscopy (SEM). The results reaffirm the great diversity in Annonaceae at the pollen morphological level, with the size of pollen varying from small, medium-sized to large, the shape of monads being elliptic, spheroidal or triangular with monosulcate, disulculate or no visible aperture, and the shape of tetrads being tetragonal, rhomboidal, tetrahedral, T-shaped or decussate. Ornamentation is echinate, psilate, microreticulate, rugulate, scabrate or verrucate. Decussate tetrads in Goniothalamus, and tetragonal, rhomboidal, T-shaped and decussate tetrads and new tetrad type in Mitrephora are first reported. The pollen grains of Anaxagorea show slightly bilateral and no visible aperture as a result of intine extrusion. The palynological evidence confirms the close relationship of Dasymaschalon, Desmos and Asian Friesodielsia, and shows the high diversity of pollen morphology within genera in Annonaceae.

提交时间: 2017年07月13日 点击量:95, 下载量:50

7. chinaXiv:201707.00466 [pdf]

Floral development of monoecious Pseuduvaria trimera (Annonaceae) and comparative morphology and structure of its stamens and indehiscent staminodes

Yang, Guifang; Xu, Fengxia
分类: 生物学 >> 植物学

Premise of research. Comparative development of staminate and pistillate flowers of Pseuduvaria trimera (Annonaceae) is firstly investigated to understand its sexual differentiation and developmental processes of flowers. Comparisons of morphological and anatomical features between mature stamens and staminodes are also described, in order to clarify the mode of anther dehiscence and understand the mechanism underlying the sterility of the staminodes. Methodology. Flowers at different developmental stages and mature stamens and staminodes were examined with SEM and light microscopy. Pivotal results. Flowers have complex whorled phyllotaxis as in other Annonaceae, with double positions in the outmost whorl of reproductive organs and variable stamen and carpel organ numbers per whorl. The stomium region of each theca is composed of the septum and stomium. The septum and stomium cells of stamens could be degenerated developmentally, facilitating anther opening, whereas those of staminodes maintain intact, forming indehiscent anthers. Conclusions. The developmental data suggest that staminate flower is unisexual from inception, while pistillate flower is morphologically hermaphroditic. The morphologically hermaphroditic flowers are nevertheless functionally pistillate as the anthers are indehiscent, and the structural andromonoecy of P. trimera actually functions as monoecy. The mechanism underlying the sterility of the indehiscent staminodes and delayed dehiscent outer stamens might be effective in promoting xenogamy. The occurrence of staminode is closely correlated with the acquisition and evolution of functional unisexual flowers in the genus Pseuduvaria.

提交时间: 2017年07月13日 点击量:81, 下载量:41

8. chinaXiv:201707.00079 [pdf]

Comparison of synandrium structure and development in three species from Myristicaceae

Yang, Guifang; Xu, Fengxia
分类: 生物学 >> 植物学

Species of Myristicaceae have diverse and distinctive synandria morphology and structure, making them an interesting group for androecium evolution research. To clarify the morphology, structure, and origin of the synandrium, scanning electron microscopy and histology were performed on staminate inflorescences and flowers of Horsfieldia pandurifolia, H. tetratepala, and Myristica fragrans at different developmental stages. A whorl of stamen primordia was initiated rapidly around the margin of the floral apex in groups of two in H. pandurifolia and groups of three in M. fragrans. Each stamen primordium grew longitudinally, producing a pair of anther lobes and four microsporangia, accompanying one vascular bundle in H. pandurifolia and M. fragrans. In H. tetratepala, three stamen primordia groups were formed and each group with several anthers was supported by one vascular bundle, indicating a secondary increase of stamen. Three types of synandria origins were observed—in M. fragrans, the central sterile column tissues originated from the elongate receptacle; in H. pandurifolia and H. tetratepala, they were derived from a combination of floral meristem and fused connectives, and a combination of receptacular tissue and stamen groups. The diverse origins of the central sterile column suggest that the synandrium develops differently and independently in different genera and species of Myristicaceae.

提交时间: 2017年07月12日 点击量:5, 下载量:3

9. chinaXiv:201707.00074 [pdf]

Canopy stomatal uptake of NOX, SO2 and O3 by mature urban plantations based on sap flow measurement

Hu, Yanting; Zhao, Ping; Niu, Junfeng; Sun, Zhenwei; Zhu, Liwei; Ni, Guangyan
分类: 生物学 >> 植物学

Canopy stomatal uptake of NOX (NO, NO2), SO2 and O3 by three mature urban plantations (of Schima superba, Eucalyptus citriodora and Acacia auriculaeformis) were studied using the sap flow-based approach under free atmospheric conditions. The annual mean concentration for NO, NO2, SO2 and O3 were 18.17, 58.05, 12.76 and 42.36 μg•m-3, respectively. The atmospheric concentration exhibited a spring or winter maximum for NO, NO2 and SO2, whereas the concentration maxima for O3 occurred in the autumn. Despite the daytime mean canopy stomatal conductance (GC) being positively related with the photosynthetically active radiation (PAR) and negatively with the vapour pressure deficit (VPD), the maximal daytime mean GC did not appear when the PAR was at its highest level or the VPD was at its lowest level because a positive correlation was noted between the daytime mean PAR and VPD (P<0.001) under field conditions. The GC value was regulated by the cooperation of the PAR and VPD. When analysing the respective effect of the PAR or VPD on GC separately, a positive logarithmical correlation was noted between the daytime mean GC and PAR as the following equation: G_c=a×lnPAR-b (P<0.01), and the daytime mean GC was negatively logarithmically correlated with the VPD: G_c=G_sref-m×lnVPD (P <0.001). The daytime mean GC declined with decreases in the soil water content (SWC) under similar meteorological condition. Differences in the seasonal pattern of the canopy stomatal conductance and atmospheric concentrations led to a differentiated peak flux. The flux for NO, NO2 and SO2 exhibited a spring maximum, whereas the flux maxima for O3 appeared in the autumn or summer. The annual accumulative stomatal flux for NO, NO2, SO2 and O3 was 100.19±3.76, 510.68±24.78, 748.59±52.81 and 151.98±9.33 mg•m-2•a-1, respectively. When we focus on the foliar uptake of trace gases, the effect of these gases on the vegetation in turn should be considered, particularly for regions with serious air pollution problems. These trace gases had not yet reached injury levels, except for NO2. Flux-based measurements were better suited for evaluating the risk of O3 damage to vegetation than the exposure-based method.

提交时间: 2017年07月12日 点击量:127, 下载量:66

10. chinaXiv:201707.00063 [pdf]

Mouse model with age-dependent immune response and immune-tolerance for HBV infection

分类: 生物学 >> 生物医药 生物学 >> 病毒学

Objective: Viral clearance of human HBV infection largely depends on the age of exposure, so a mouse model with age-dependent immune response and immune-tolerance for HBV infection is essential. Methods: HBVRag1 mice were generated by crossing Rag1-/- mice with HBV-Tg mice. The differences between adult and young HBVRag1 mice were detected after adoptive transfer of splenocytes. Immune tolerance was evaluated by quantitative hepatitis B core antibody (qAnti-HBc) assay, adoptive transfer, and modulation of gut microbiota with antibiotic. Results: After HBVRag1 mouse reconstitution, adult mice showed obvious HBV-dependent inflammation and hepatocytes damage, cleared HBsAg and generated HBsAb and HBcAb, but young mice never developed ALT elevation, and only generated HBcAb with persistence of HBsAg. In addition, for adult mice, more hepatic CD8+T and B cells promoted clearance of HBsAg 30 days after lymphocytes transfer, and for young mice, higher levels of cytokines link to the persistence of viral antigens during initiation of immune response towards HBV. The level of qAnti-HBc increased significantly with the time of adoptive transfer in young mice, but decreased significantly in adult within our model. This mimics kinetic changes of human HBV infection regarding qAnti-HBc level. Also, the age-related tolerance in this model was different from which was in HBV-Tg mice, and can be regulated through modulation of gut microbiota. Meanwhile, GS-9620 can achieve inhibition of HBsAg, but HBV vaccine just clears limited HBsAg within the model. Conclusions: Here, we described a mouse model with age-dependent immune response and immune tolerance of HBV infection which could mimic chronic HBV infection in human. It will open a door for evaluating new therapeutic approaches before clinical trials.

提交时间: 2017年07月11日 点击量:95, 下载量:52

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