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Recognizing mixed urban functions from human activities using representation learning methods

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International Journal of Digital Earth 2023年第1期16卷 289-307页

作者： Junjie Hu Yong Gao xuechen wang Yu Liu Institute of Remote Sensing and Geographical Information System School of Earth and Space SciencesPeking UniversityBeijingPeople's Republic of China

When various urban functions are integrated into one location,they form a mixture of *** emerging big data promote an alternative way to identify mixed ***,current methods are largely unable to extract deep features in these data,resulting in low *** this study,we focused on recognizing mixed urban functions from the perspective of human activities,which are essential indicators of functional areas in a *** proposed a framework to comprehensively extract deep features of human activities in big data,including activity dynamics,mobility interactions,and activity semantics,through representation learning ***,integrating these features,we employed fuzzy clustering to identify the mixture of urban *** conducted a case study using taxiflow and social media data in Beijing,China,in whichfive urban functions and their correlations with land use were *** mixture degree of urban functions in each location was revealed,which had a negative correlation with taxi trip *** results confirmed the advantages of our method in understanding mixed urban functions by employing various representation learning methods to comprehensively depict human *** study has important implications for urban planners in understanding urban systems and developing better strategies.

关键词： Mixed urban function human activity representation learning spatiotemporal data mining

Identification and role of plasma membrane aquaporin in maize root

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Chinese Science Bulletin 2000年第16期45卷 1493-1496页

作者： Meijun Zhu xuechen wang Jia Chen China Agr Univ Lab Plant Physiol & Biochem Minist Agr Coll Biol Sci Beijing 100094 Peoples R China

Using antiserum against expressed aquaporin fusion protein, GST-RD28, the distribution of aquaporin in the plasma membrane of maize root protoplasts has been examined under confocal laser scanning microscopy by indirect fluorescence staining. Results indicate that there are abundant aquaporins in maize roots, which are distributed in plasma membrane unevenly. Western blotting analysis of total protein solubilized from maize root plasma membrane shows that antiserum against GST-RD28 can cross-react with one protein around 55 ku. Another 28 ku protein can also be detected when the concentration of SDS and DTT in SDS-PAGE sample buffer is increased. The 55 and 28 ku proteins may be dimeric and monomeric of aquaporin respectively. Functional experiments show that aquaporin blocker HgCI2 and aquaporin antiserum can suppress the swelling of maize root protoplasts in hypotonic solution, indicating that aquaporin in plasma membrane of protoplast facilitates rapid transmembrane water flow.

关键词： aquaporin plasma membrane transmembrane water flow maize roots.

Muscarinic acetylcholine receptor is involved in acetylcholine regulating stomatal movement

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Chinese Science Bulletin 2000年第3期45卷 250-252页

作者： Hengbin wang xuechen wang Shuqiu Zhang Chenghou Lou China Agr Univ Coll Biol Sci Beijing 100094 Peoples R China

In animal cells, action of acetylcholine depends on its binding with its two specific receptors on the plasma membrane: the nicotinic and muscarinic respectively. The present investigation has shown that agonists of muscarinic receptor (muscarine) could induce stomatal opening, while the antagonists (atropine) could block stomatal opening induced by acetylcholine. Their effects can only be realized in medium containing Ca2+, but not in medium containing K+. The results tend to reveal that the muscarinic receptor is involved in acetylcholine-induced stomatal movement.

关键词： Viciafaba L. stomata movement acetylcholine muscarinic receptor.

Rearrangements of microtubule cytoskeleton in stomatal closure of Arabidopsis induced by nitric oxide

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Chinese Science Bulletin 2008年第6期53卷 848-852页

作者： ZHANG YongMei WU ZhongYi wang xuechen YU Rong College of Life Sciences Capital Normal University Beijing 100037 China Beijing Agro-Biotechnology Research Center Beijing Academy of Agriculture and Forestry Sciences Beijing 100097 China State Key Laboratory of Plant Physiology and Biochemistry College of Biological Sciences China Agricultural University Beijing 100094 China

NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (i) In vivo stomatal aperture assays revealed that both vinblastine (microtubule-disrupting drug) and SNP (exogenous NO donor) prevented stomatal opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas taxol (a microtubule-stabilizing agent) was able to reduce this effect; (ii) microtubules in the opening Arabi- dopsis guard cells expressing GFP:α-tubulin-6 (AtGFP:α-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (iii) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be- came oblique or exhibited a random pattern; (iv) furthermore, the involvement of cytosolic Ca2+ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca2+) greatly sup- pressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca2+]cyt (free Ca2+ concentration in the cy- toplasm), finally leading to stomatal closure.

关键词：氧化一氮微管细胞骨架气孔运动气孔关闭钙离子

Regulation of the inward K^+-channels in stomatal guard cells by cytoskeletal microtubules

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Chinese Science Bulletin 1999年第10期44卷 919-923页

作者： Ximing Zhou Weihua Wu Ming Yuan xuechen wang China Agr Univ Coll Biol Dept Plant Sci Beijing 100094 Peoples R China

Patch clamp techniques were applied to investigating the regulation of the inward K^+channels in Vicia stomatal guard cells by cytoskeletal microtubules. The intracellular addition of either microtubule-disassembling reagent amprophos-methyl (APM) or microtubule-stabilizing reagent taxol resulted in significant inhibition of the inward K^+ -currents across the plasma membranes of Vicia stomatal guard cells. The results suggest that the activation of the inward K^+channels in stomatal guard cells requires proper dynamic organization of cytoskeletal microtubules. The regulation of the inward K^+-channels in guard cells by microtubules may mediate the regulation of stomatal movements by cytoskeleton.

关键词： microtubules stomatal regulation K+ -channels.

Identification of integrin-like in guard cells of Vicia faba

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Chinese Science Bulletin 2001年第13期46卷 1100-1103页

作者： ZHANG Aihua HUANG Rongfeng wang xuechen YUAN Ming College of Biological Sciences China Agricultural UniversityBeijing100094China Biotechnology Research Institute Chinese Academy of Agricultural SciencesBeijing 100081China Key Lab of Plant Physiology&Biochemistry The Ministry of AgricultureBeijing 100094China

We addressed the existence and localization of integrin-like in guard cells of Vicia faba by using a probe of polyclonal antibody against the human integrin (αvβ3/β5)-Western blot results showed that three integrins-like of about 47.3, 43.7 and 41.1 ku were detected from the preparation of membrane fragments of purified guard cell protoplasts. Further research with immunofluorescent scanning microscopy indicated that those integrins-like were localized on plasma membrane of guard cells, most nearing the dorsal wall, which is consistent with the reception of signals from epidermal cells to guard cells. Thus our results indicate, for the first time, that integrins-like are present at guard cell plasma membrane of Vicia faba.

关键词： integrins-like guard cells Viciafaba signal transduction.

Hydrogen sulfide induced by nitric oxide mediates ethylene-induced stomatal closure of Arabidopsis thaliana

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Chinese Science Bulletin 2011年第33期56卷 3547-3553页

作者： LIU Jing HOU LiXia LIU GuoHua LIU Xin wang xuechen Key Laboratory of Plant Biotechnology in Universities of Shandong Life Sciences College Qingdao Agricultural University Qingdao 266109 China State Key Laboratory of Plant Physiology and Biochemistry College of Biological Sciences China Agricultural University Beijing 100094 China

Pharmacological, laser scanning confocal microscopic (LSCM), real-time PCR and spectrophotographic approaches are used to study the roles of hydrogen sulfide (H2S) and nitric oxide (NO) in signaling transduction of stomatal movement response to ethylene in Arabidopsis thaliana. In the present study, inhibitors of H2S synthesis were found to block ethylene-induced stomatal closure of Arabidopsis. Treatment with ethylene induced H2S generation and increased L-/D-cysteine desulfhydrase (pyridoxal-phosphate-dependent enzyme) activity in leaves. Quantitative PCR analysis showed AtL-CDes and AtD-CDes transcripts were induced by ethylene. It is suggested that ethylene-induced H2S levels and L-/D-cysteine desulfhydrase activity decreased when NO was compromised. The data clearly show that ethylene was able to induce H2S generation and stomatal closure in Atnoa1 plants, but failed in the Atnia1,nia2 mutant. Inhibitors of H2S synthesis had no effect on ethylene-induced NO accumulation and nitrate reductase (NR) activity in guard cells or leaves of Arabidopsis, whereas ethylene was able to induce NO synthesis. Therefore, we conclude that H2S and NO are involved in the signal transduction pathway of ethylene-induced stomatal closure. In Arabidopsis, H2S may represent a novel downstream indicator of NO during ethylene-induced stomatal movement.

关键词：气孔关闭一氧化氮硫化氢拟南芥诱导乙烯激光扫描共聚焦显微镜信号转导通路

Increment of antioxidase activity of transgenic tobacco with betaine aldehyde dehydrogenase

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Chinese Science Bulletin 2001年第6期46卷 492-495页

作者： LUO Ailing LIU Jaoyao MA Deqin wang xuechen LIANG Zheng Photosynthesis Research Center Institute of BotanyChinese Academy of SciencesBeijing 100093China Institute of Microbiology Chinese Academy of SciencesBeijing 100080China Chinese Agricultural University Beijing 100094China

Superoxide dismutase (SOD) activity in the leaves of transgenic tobacco plants with betaine aldehyde dehydrogenase (BADH) gene was about 36% higher than that in the control plants (parent plants), activities of per-oxidase (POD) and catalase (Cat) increased by about 62% and 88% respectively. Activities of ascorbate peroxidase (AsSPOD), dehydroascorbate redutase (DAsAR) and glu-tathione reductase (GR) in ascorbate-glutothion pathway located at chloroplasts increased by 67.7%, 47.9% and 38.8% respectively. These results indicated that the H2O2 produced by SOD catalyzing superoxide anion radicals (O2-) could be fully decomposed, and could not derive to form the strongest toxicant radicals · OH. This is the first report to elucidate quantitatively that the activities of two kinds of antioxidative enzymes decomposed radicals and active oxygen were matched. Photoinhibition tolerant capacity of the transgenic tobacco plants was 35% higher than that in the parent plants. Increment of photoinhibition tolerant

关键词： betaind aldehyde dehydrogenase gene tobacco antioxi- dative enzymes activities.

Identification of AtSM34, a novel tonoplast intrinsic protein-interacting polypeptide expressed in response to osmotic stress in germinating seedlings

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Chinese Science Bulletin 2011年第33期56卷 3518-3530页

作者： LI LiJuan REN Fei WEI PengCheng CHEN QiJun CHEN Jia wang xuechen State Key Laboratory of Plant Physiology and Biochemistry College of Biological Sciences China Agricultural University Beijing 100193 China Institute of Forestry and Pomology Beijing Academy of Agriculture and Forestry Sciences Beijing 100093 China

Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using AtTIP1;1 as bait, a novel binding protein was identified in both yeast and plant cells. This prey protein, named AtSM34, was a 309 aa polypeptide with a predicted molecular mass of 34 kD and contained a single MYB/SANT-like domain. AtSM34 promoter:: GUS histochemical staining analysis detected AtSM34 expression in flowers, stems and leaves, particularly in the vascular tissues, in response to osmotic stress. AtSM34 expression was localized in the endoplasmic reticulum membrane, and sequence deletion analysis revealed that the N-terminal coding region (amino acids 1-83) was critical for this localization. Overexpression of AtSM34 resulted in hypersensitivity to exogenous mannitol, sorbitol and abscisic acid, and caused a significant delay in germination. AtSM34 interacted with AtTIP1;2 and AtTIP2;1, which are essential proteins for modulation of tonoplast permeability and highly expressed in germinating seedlings. These data indicate AtSM34 is a novel TIPs binding protein involved in the osmotic stress response of seedlings at an early stage of development.

关键词：蛋白质相互作用渗透胁迫液泡膜幼苗多肽酵母双杂交系统组织化学染色鉴定