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Liu B, Zhang C, Deng J, Zhang B, Chen F, Chen W, Fang X, Li J, Zu K, Bu W. Response of tree growth to nutrient addition is size dependent in a subtropical forest. Sci Total Environ 2024; 923:171501. [PMID: 38447724 DOI: 10.1016/j.scitotenv.2024.171501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/03/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024]
Abstract
Understanding how nutrient addition affects the tree growth is critical for assessing forest ecosystem function and processes, especially in the context of increased nitrogen (N) and phosphorus (P) deposition. Subtropical forests are often considered N-rich and P-poor ecosystems, but few existing studies follow the traditional "P limitation" paradigm, possibly due to differences in nutrient requirements among trees of different size classes. We conducted a three-year fertilization experiment with four treatments (Control, N-treatment, P-treatment, and NP-treatment). We measured soil nutrient availability, leaf stoichiometry, and relative growth rate (RGR) of trees across three size classes (small, medium and large) in 64 plots. We found that N and NP-treatments increased the RGR of large trees. P-treatment increased the RGR of small trees. RGR was mainly affected by N addition, the total effect of P addition was only 10 % of that of N addition. The effect of nutrient addition on RGR was mainly regulated by leaf stoichiometry. This study reveals that nutrient limitation is size dependent, indicating that continuous unbalanced N and P deposition will inhibit the growth of small trees and increase the instability of subtropical forest stand structure, but may improve the carbon sink function of large trees.
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Affiliation(s)
- Bin Liu
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China; Key Laboratory of Forest Ecology and Environment of the National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China
| | - Cancan Zhang
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China; Jiulianshan National Observation and Research Station of Chinese Forest Ecosystem, Jiangxi Agricultural University, Nanchang 330045, China
| | - Jun Deng
- Administration of Jiulianshan National Nature Reserve, Ganzhou 341799, China
| | - Bowen Zhang
- Administration of Jiulianshan National Nature Reserve, Ganzhou 341799, China
| | - Fusheng Chen
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China; Jiulianshan National Observation and Research Station of Chinese Forest Ecosystem, Jiangxi Agricultural University, Nanchang 330045, China
| | - Wei Chen
- Administration of Jiulianshan National Nature Reserve, Ganzhou 341799, China
| | - Xiangmin Fang
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China
| | - Jianjun Li
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China
| | - Kuiling Zu
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China
| | - Wensheng Bu
- Key Laboratory of State Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Provincial Key Laboratory of Conservation Biology, College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China; Jiulianshan National Observation and Research Station of Chinese Forest Ecosystem, Jiangxi Agricultural University, Nanchang 330045, China.
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Luo A, Li Y, Shrestha N, Xu X, Su X, Li Y, Lyu T, Waris K, Tang Z, Liu X, Lin L, Chen Y, Zu K, Song W, Peng S, Zimmermann NE, Pellissier L, Wang Z. Global multifaceted biodiversity patterns, centers, and conservation needs in angiosperms. Sci China Life Sci 2024; 67:817-828. [PMID: 38217639 DOI: 10.1007/s11427-023-2430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 08/03/2023] [Indexed: 01/15/2024]
Abstract
The Convention on Biological Diversity seeks to conserve at least 30% of global land and water areas by 2030, which is a challenge but also an opportunity to better preserve biodiversity, including flowering plants (angiosperms). Herein, we compiled a large database on distributions of over 300,000 angiosperm species and the key functional traits of 67,024 species. Using this database, we constructed biodiversity-environment models to predict global patterns of taxonomic, phylogenetic, and functional diversity in terrestrial angiosperms and provide a comprehensive mapping of the three diversity facets. We further evaluated the current protection status of the biodiversity centers of these diversity facets. Our results showed that geographical patterns of the three facets of plant diversity exhibited substantial spatial mismatches and nonoverlapping conservation priorities. Idiosyncratic centers of functional diversity, particularly of herbaceous species, were primarily distributed in temperate regions and under weaker protection compared with other biodiversity centers of taxonomic and phylogenetic facets. Our global assessment of multifaceted biodiversity patterns and centers highlights the insufficiency and unbalanced conservation among the three diversity facets and the two growth forms (woody vs. herbaceous), thus providing directions for guiding the future conservation of global plant diversity.
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Affiliation(s)
- Ao Luo
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yaoqi Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Xiaoting Xu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Xiangyan Su
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
- Land Consolidation and Rehabilitation Center, Ministry of Natural Resources, Beijing, 100035, China
| | - Yichao Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Tong Lyu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Kilara Waris
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Zhiyao Tang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Xiaojuan Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Luxiang Lin
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yongsheng Chen
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Kuiling Zu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Wenqi Song
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Shijia Peng
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Niklaus E Zimmermann
- Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, 8092, Switzerland
| | - Loïc Pellissier
- Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, 8092, Switzerland
| | - Zhiheng Wang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
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Zu K, Zhang C, Chen F, Zhang Z, Ahmad S, Nabi G. Latitudinal gradients of angiosperm plant diversity and phylogenetic structure in China’s nature reserves. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
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Zu K, Arunachalam A, Macdonald S, Wang Y, Wells K, Oliveria S, Pietanza M. P63.05 Treatment Pattern in Small Cell Lung Cancer: A Real-world Observational Study in the Era of Immune Checkpoint Inhibitors. J Thorac Oncol 2021. [DOI: 10.1016/j.jtho.2021.08.661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zu K, Arunachalam A, Hohlbauch A, Silver M, Annavarapu S, Pietanza M. P63.08 Real-World Utilization of Immune Checkpoint Inhibitors in Extensive Stage Small Cell Lung Cancer in Community Settings. J Thorac Oncol 2021. [DOI: 10.1016/j.jtho.2021.08.664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zu K, Wang Z, Zhu X, Lenoir J, Shrestha N, Lyu T, Luo A, Li Y, Ji C, Peng S, Meng J, Zhou J. Upward shift and elevational range contractions of subtropical mountain plants in response to climate change. Sci Total Environ 2021; 783:146896. [PMID: 33866165 DOI: 10.1016/j.scitotenv.2021.146896] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/07/2021] [Accepted: 03/28/2021] [Indexed: 06/12/2023]
Abstract
Elevational range shifts of mountain species in response to climate change have profound impact on mountain biodiversity. However, current evidence indicates great controversies in the direction and magnitude of elevational range shifts across species and regions. Here, using historical and recent occurrence records of 83 plant species in a subtropical mountain, Mt. Gongga (Sichuan, China), we evaluated changes in species elevation centroids and limits (upper and lower) along elevational gradients, and explored the determinants of elevational changes. We found that 63.9% of the species shifted their elevation centroids upward, while 22.9% shifted downward. The changes in centroid elevations and range size were more strongly correlated with changes in lower than upper limits of species elevational ranges. The magnitude of centroid elevation shifts was larger than predicted by climate warming and precipitation changes. Our results show complex changes in species elevational distributions and range sizes in Mt. Gongga, and that climate change, species traits and climate adaptation of species all influenced their elevational movement. As Mt. Gongga is one of the global biodiversity hotspots, and contains many threatened plant species, these findings provide support to future conservation planning.
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Affiliation(s)
- Kuiling Zu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhiheng Wang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
| | - Xiangyun Zhu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jonathan Lenoir
- UR "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN, UMR 7058 CNRS-UPJV), Université de Picardie Jules Verne, 1 Rue des Louvels, 80037 Amiens Cedex 1, France
| | - Nawal Shrestha
- State Key Laboratory of Grassland Agroecosystem, Institute of Innovation Ecology, Lanzhou University, Lanzhou 730000, China
| | - Tong Lyu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Ao Luo
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yaoqi Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Chengjun Ji
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Shijia Peng
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Jiahui Meng
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Jian Zhou
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
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Zu K, Luo A, Shrestha N, Liu B, Wang Z, Zhu X. Altitudinal biodiversity patterns of seed plants along Gongga Mountain in the southeastern Qinghai-Tibetan Plateau. Ecol Evol 2019; 9:9586-9596. [PMID: 31534677 PMCID: PMC6745871 DOI: 10.1002/ece3.5483] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 01/16/2023] Open
Abstract
The mechanisms underlying elevation patterns in species and phylogenetic diversity remain a central issue in ecology and are vital for effective biodiversity conservation in the mountains. Gongga Mountain, located in the southeastern Qinghai-Tibetan Plateau, represents one of the longest elevational gradients (ca. 6,500 m, from ca. 1,000 to 7,556 m) in the world for studying species diversity patterns. However, the elevational gradient and conservation of plant species diversity and phylogenetic diversity in this mountain remain poorly studied. Here, we compiled the elevational distributions of 2,667 native seed plant species occurring in Gongga Mountain, and estimated the species diversity, phylogenetic diversity, species density, and phylogenetic relatedness across ten elevation belts and five vegetation zones. The results indicated that species diversity and phylogenetic diversity of all seed plants showed a hump-shaped pattern, peaking at 1,800-2,200 m. Species diversity was significantly correlated with phylogenetic diversity and species density. The floras in temperate coniferous broad-leaved mixed forests, subalpine coniferous forests, and alpine shrublands and meadows were significantly phylogenetically clustered, whereas the floras in evergreen broad-leaved forests had phylogenetically random structure. Both climate and human pressure had strong correlation with species diversity, phylogenetic diversity, and phylogenetic structure of seed plants. Our results suggest that the evergreen broad-leaved forests and coniferous broad-leaved mixed forests at low to mid elevations deserve more conservation efforts. This study improves our understanding on the elevational gradients of species and phylogenetic diversity and their determinants and provides support for improvement of seed plant conservation in Gongga Mountain.
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Affiliation(s)
- Kuiling Zu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of BotanyChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Ao Luo
- Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijingChina
| | - Nawal Shrestha
- Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijingChina
| | - Bo Liu
- Minzu University of ChinaBeijingChina
| | - Zhiheng Wang
- Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijingChina
| | - Xiangyun Zhu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of BotanyChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
- Southeast Asia Biodiversity Research InstituteChinese Academy of SciencesNay Pyi TawMyanmar
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Lynch HN, Zu K, Kennedy EM, Lam T, Liu X, Pizzurro DM, Loftus CT, Rhomberg LR. Corrigendum to "Quantitative assessment of lung and bladder cancer risk and oral exposure to inorganic arsenic: Meta-regression analyses of epidemiological data" Environmental International 106 :178-206. Environ Int 2017; 109:195-196. [PMID: 29078863 DOI: 10.1016/j.envint.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- H N Lynch
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - K Zu
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - E M Kennedy
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - T Lam
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - X Liu
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - D M Pizzurro
- Gradient, 20 University Road, Cambridge, MA02138, USA
| | - C T Loftus
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, 4225 Roosevelt Way NE, Suite 301, Seattle, WA 98105, USA
| | - L R Rhomberg
- Gradient, 20 University Road, Cambridge, MA02138, USA.
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Zu K, Pizzurro DM, Lewandowski TA, Goodman JE. Pharmacokinetic data reduce uncertainty in the acceptable daily intake for benzoic acid and its salts. Regul Toxicol Pharmacol 2017; 89:83-94. [PMID: 28720346 DOI: 10.1016/j.yrtph.2017.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 01/01/2023]
Abstract
The current acceptable daily intake (ADI) for benzoic acid and its salts as food additives is 0-5 mg/kg body weight. This accounts for a total uncertainty factor (UF) of 100, which includes a default factor of 10 for interspecies differences. Based on pharmacokinetic data in rodents and humans, we derived a chemical-specific adjustment factor (CSAF) of 2 for the pharmacokinetic component of the interspecies UF. Additional analyses indicate that this CSAF is conservative and interspecies differences between rats and humans are likely closer to unity. Human clinical studies indicate that the pharmacokinetics of benzoic acid and its salts are similar in children and adults, and that there is a lack of adverse events in humans at doses comparable to the no observed adverse effect level (NOAEL) in rodents; this suggests that the pharmacokinetic UF for intraspecies variability, as well as the pharmacodynamic components of the UFs, may also be reduced, although we did not calculate to what degree. In conclusion, the total UF can be reduced to 50 (2 for interspecies differences in pharmacokinetics, 2.5 for interspecies differences in pharmacodynamics, and 10 for intraspecies variability), which would increase the ADI to 0-10 mg/kg body weight.
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Affiliation(s)
- K Zu
- Gradient, 20 University Road, Cambridge, MA, 02138, USA
| | - D M Pizzurro
- Gradient, 20 University Road, Cambridge, MA, 02138, USA
| | - T A Lewandowski
- Gradient, 600 Stewart Street, Suite 1900, Seattle, WA, 98101, USA
| | - J E Goodman
- Gradient, 20 University Road, Cambridge, MA, 02138, USA.
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Zu K, Li J, Dong S, Zhao Y, Xu S, Zhang Z, Zhao L. Morphogenesis and global analysis of transcriptional profiles of Celastrus orbiculatus aril: unravelling potential genes related to aril development. Genes Genomics 2017. [DOI: 10.1007/s13258-017-0528-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zu K, Bihani T, Lin A, Park YM, Mori K, Ip C. Enhanced selenium effect on growth arrest by BiP/GRP78 knockdown in p53-null human prostate cancer cells. Oncogene 2006; 25:546-54. [PMID: 16205645 PMCID: PMC2424019 DOI: 10.1038/sj.onc.1209071] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 08/01/2005] [Accepted: 08/01/2005] [Indexed: 11/09/2022]
Abstract
Redox modification of thiol/disulfide interchange in proteins by selenium could lead to protein unfolding. When this occurs in the endoplasmic reticulum (ER), a process known as unfolded protein response (UPR) is orchestrated for survival through activation of PERK-eIF2alpha (PERK: double-stranded RNA-activated protein kinase-like ER kinase; eIF2alpha: eucaryotic initiation factor 2alpha), ATFalpha (ATFalpha: activating transcription factor 6) and inositol requiring 1 (IRE1)-x-box-binding protein 1 (XBP1) signalings. All three UPR transducer pathways were upregulated very rapidly when PC-3 cells were exposed to selenium. These changes were accompanied by increased expression of UPR target genes, including immunoglobulin heavy chain-binding protein/glucose-regulated protein, 78 kDa and CCAAT/enhancer binding protein-homologous protein/growth arrest- and DNA damage-inducible gene (CHOP/GADD153). Induction of BiP/GRP78, an ER-resident chaperone, is part of the damage control mechanism, while CHOP/GADD153 is a transcription factor associated with growth arrest and apoptosis in the event of prolonged ER stress. Knocking down BiP/GRP78 induction by small interference RNA produced a differential response of the three transducers to selenium, suggesting that the signaling intensity of each transducer could be fine-tuned depending on BiP/GRP78 availability. In the presence of selenium, CHOP/GADD153 expression was raised even higher by BiP/GRP78 knockdown. Under this condition, the selenium effect on wild-type p53-activated fragment p21 (p21(WAF)), cyclin-dependent kinase (CDK)1 and CDK2 was also magnified in a manner consistent with enhanced cell growth arrest. Additional experiments with CHOP/GADD153 siRNA knockdown strongly suggested that CHOP/GADD153 may play a positive role in upregulating the expression of p21(WAF) in a p53-independent manner (PC-3 cells are p53 null). Collectively, the above findings support the idea that UPR could be an important mechanism in mediating the anticancer activity of selenium.
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Affiliation(s)
- K Zu
- Department of Cancer Chemoprevention, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - T Bihani
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - A Lin
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Y-M Park
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - K Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - C Ip
- Department of Cancer Chemoprevention, Roswell Park Cancer Institute, Buffalo, NY, USA
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Abstract
We analyzed the roles of the three domains of a Drosophila hnRNP A1 homolog by expression of wild-type and mutant versions of HRB87F/hrp36 in Drosophila melanogaster. HRB87F/hrp36 is one of two Drosophila proteins that is most similar to mammalian A1 hnRNP, and like A1, consists of two copies of the RNA-binding domain (RBD) motif followed by a glycine-rich domain (GRD). The role of the domains in nuclear localization and RNA binding to polytene chromosomal sites was determined. RBD-1 and the GRD were largely responsible for both the cellular location of the protein and for the typical chromosomal distribution pattern of the protein at sites of PolII transcription. RBD-1 also provided a role in the exon-skipping activity of the protein that was not provided by RBD-2. On the other hand, RBD-2 and the GRD were responsible for the very limited chromosomal distribution pattern seen upon heat shock, when HRB87F/hrp36 is sequestered at heat-shock puff 93D, which encodes a long nucleus-restricted RNA. Thus, these studies indicate that the two RBDs function independently of each other but in concert with the GRD. In addition, the self-association property of the GRD was strikingly evident in these overexpressed proteins.
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Affiliation(s)
- K Zu
- Department of Microbiology, University of Virginia, Charlottesville 22908, USA
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Zu K, Sikes ML, Haynes SR, Beyer AL. Altered levels of the Drosophila HRB87F/hrp36 hnRNP protein have limited effects on alternative splicing in vivo. Mol Biol Cell 1996; 7:1059-73. [PMID: 8862520 PMCID: PMC275958 DOI: 10.1091/mbc.7.7.1059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Drosophila melanogaster genes Hrb87F and Hrb98DE encode the fly proteins HRB87F and HRB98DE (also known as hrp36 and hrp38, respectively) that are most similar in sequence and function to mammalian A/B-type hnRNP proteins. Using overexpression and deletion mutants of Hrb87F, we have tested the hypothesis that the ratio of A/B hnRNP proteins to SR family proteins modulates certain types of alternative splice-site selection. In flies in which HRB87F/hrp36 had been overexpressed 10- to 15-fold above normal levels, aberrant internal exon skipping was induced in at least one endogenous transcript, the dopa decarboxylase (Ddc) pre-mRNA, which previously had been shown to be similarly affected by excess HRB98DE/hrp38. In a second endogenous pre-mRNA, excess HRB87F/hrp36 had no effect on alternative 3' splice-site selection, as expected from mammalian hnRNP studies. Immunolocalization of the excess hnRNP protein showed that it localized correctly to the nucleus, specifically to sites on or near chromosomes, and that the peak of exon-skipping activity in Ddc RNA correlated with the peak of chromosomally associated hnRNP protein. The chromosomal association and level of the SR family of proteins were not significantly affected by the large increase in hnRNP proteins during this time period. Although these results are consistent with a possible role for hnRNP proteins in alternative splicing, the more interesting finding was the failure to detect significant adverse effects on flies with a greatly distorted ratio of hnRNPs to SR proteins. Electron microscopic visualization of the general population of active genes in flies overexpressing hnRNP proteins also indicated that the great majority of genes seemed normal in terms of cotranscriptional RNA processing events, although there were a few abnormalities consistent with rare exon-skipping events. Furthermore, in a Hrb87F null mutant, which is viable, the normal pattern of Ddc alternative splicing was observed, indicating that HRB87F/hrp36 is not required for Ddc splicing regulation. Thus, although splice-site selection can be affected in at least a few genes by gross overexpression of this hnRNP protein, the combined evidence suggests that if it plays a general role in alternative splicing in vivo, the role can be provided by other proteins with redundant functions, and the role is independent of its concentration relative to SR proteins.
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Affiliation(s)
- K Zu
- Department of Microbiology, University of Virginia, Charlottesville 22908, USA
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Shen J, Zu K, Cass CL, Beyer AL, Hirsh J. Exon skipping by overexpression of a Drosophila heterogeneous nuclear ribonucleoprotein in vivo. Proc Natl Acad Sci U S A 1995; 92:1822-5. [PMID: 7892184 PMCID: PMC42374 DOI: 10.1073/pnas.92.6.1822] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are abundant RNA-binding proteins that are implicated in splicing regulation. Here we investigate the role of a Drosophila hnRNP in splicing regulation in living animals. We find that overexpression of the Drosophila hnRNP HRB98DE leads to skipping of all internal exons in the Drosophila dopa decarboxylase (Ddc) pre-mRNA in vivo. These results indicate that HRB98DE has a splicing activity that promotes use of terminal splice sites. The effect of excess HRB98DE on Ddc splicing is transient, even though high levels of HRB98DE persist for at least 24 hr. This suggests that Drosophila larvae can induce a compensating mechanism to counteract the effects of excess HRB98DE.
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Affiliation(s)
- J Shen
- Department of Biology, University of Virginia, Charlottesville 22903
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Her JH, Lakhani S, Zu K, Vila J, Dent P, Sturgill TW, Weber MJ. Dual phosphorylation and autophosphorylation in mitogen-activated protein (MAP) kinase activation. Biochem J 1993; 296 ( Pt 1):25-31. [PMID: 7504457 PMCID: PMC1137650 DOI: 10.1042/bj2960025] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
p42mapk [mitogen activated protein (MAP) kinase; extracellular signal-regulated protein kinase (ERK)] is a serine/threonine-specific protein kinase that is activated by dual tyrosine and threonine phosphorylation in response to diverse agonists. Both the tyrosine and threonine phosphorylations are necessary for full enzymic activity. A MAP kinase activator recently purified and cloned has been shown to be a protein kinase (MAP kinase kinase) that is able to induce the dual phosphorylation of MAP kinase on both the regulatory tyrosine and threonine sites in vitro. In the present paper we have utilized MAP kinase mutants altered in the sites of regulatory phosphorylation to show, both in vivo and in vitro, that phosphorylation of the tyrosine and the threonine can occur independently of one another, with no required order of phosphorylation. We also utilized kinase-defective variants of MAP kinase with mutations in either the ATP-binding loop or the catalytic loop, and obtained data suggesting that the activity or structure of the catalytic loop of MAP kinase plays an important role in its own dual phosphorylation.
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Affiliation(s)
- J H Her
- Department of Microbiology, University of Virginia, Charlottesville 22908
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