检索结果-南通市图书馆

高、低核酸含量原核生物应对资源可利用性降低和原生动物选择性摄食的适应性策略

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

中国科学：地球科学 2024年第6期54卷 1901-1913页

作者：胡晨余柳倩陈晓炜刘纪化张瑶 john BATT 肖喜林石蔷张锐骆庭伟焦念志徐大鹏厦门大学环境与生态学院厦门361102 近海海洋环境科学国家重点实验室厦门大学海洋与地球学院福建省海洋碳汇重点实验室厦门361102 Joint lab for Ocean Research and Education(lORE)of Dalhousie University Canadaand Shandong University and Xiamen UniversityXiamen 361102China 香港科技大学(广州)地球与海洋大气科学学域广州510000 山东大学海洋研究院青岛266237 Department of Oceanography Dalhousie UniversityHalifaxNova Scotia B3H 4R2Canada 深圳大学高等研究院深圳518060 厦门大学碳中和创新研究中心厦门361102

原核生物在全球海洋生物地球化学循环中发挥重要作用,然而对它们不同生态亚群(即:高核酸(HNA)和低核酸(lNA)含量亚群)的丰度和代谢活性,以及它们的调控因素如何随着海洋环境条件的变化而变化,仍知之甚少.我们在117,000升的大体积培养体... 详细信息

原核生物在全球海洋生物地球化学循环中发挥重要作用,然而对它们不同生态亚群(即:高核酸(HNA)和低核酸(lNA)含量亚群)的丰度和代谢活性,以及它们的调控因素如何随着海洋环境条件的变化而变化,仍知之甚少.我们在117,000升的大体积培养体系中进行了73天的培养实验,深入研究HNA和lNA亚群对资源可利用性降低和原生动物选择性摄食随时间变化的动态响应.研究结果显示,当培养环境资源充足时, HNA亚群的代谢活性高于lNA亚群,但随着资源日益稀缺, HNA亚群代谢下降速度比lNA亚群快,从而使lNA亚群对原核生物活性的贡献稳步增加.与此同时,随着培养体系资源可利用性逐步降低,原生动物的摄食偏好从HNA亚群转向lNA亚群,使得lNA亚群对培养体系的碳流贡献增加.这些结果突显了lNA亚群在资源有限环境中的韧性,阐明了原生动物选择性摄食在资源条件变化时平衡不同亚群中的关键作用,并展示了在不同环境背景下原生动物和原核生物之间复杂的相互适应性.

关键词：微生物环大体积培养实验原核生物自上而下和自下而上调控作用碳流

Towards estimating shade response of bermudagrass(Cynodon spp.)using field-based photosynthetic properties

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Grass Research 2022年第1期2卷 20-25,I0001-I0004页

作者： Jonathon l.Fox David Jespersen lisa l.Baxter john l.snider Marc W.van Iersel Brian M.Schwartz Department of Crop and Soil Sciences University of Georgia2360 Rainwater Rd.TiftonGA 31794USA Department of Crop and Soil Sciences University of Georgia1109 Experiment St.GriffinGA 30223USA Department of Horticulture University of Georgia1111 Plant Science BuildingAthensGA 30602USA

Shade tolerance is a highly desirable trait when breeding new bermudagrass(Cynodon spp.)lines,but current screening methods can take many years to *** is a clear need for large-scale turfgrass breeding programs to reliably,accurately,and quickly predict shade tolerance in their *** objectives of this research were to:(i)build custom chambers to reproducibly estimate photosynthetic characteristics from turfgrass canopies at different light intensities and(ii)determine which photosynthetic characteristics are indicative of past shade performance.A custom-built chamber was constructed to determine average photosynthetic characteristics for the whole plant by studying the turfgrass canopy at natural leaf angles for light *** tolerant(11-T-56)and shade sensitive(Tifway)bermudagrass cultivars were used to examine the effectiveness of the chamber within an array of photosynthetic characteristics when the grasses were grown in full-sun and 73%shade *** compensation point,chlorophyll content,quantum yield,dark respiration rate,and maximum quantum yield of photosystem II were evaluated in this *** on the results of this study,the authors recommend that light compensation point or maximum quantum yield be further evaluated as an accurate indicator of shade tolerance when performed in the field on spring days with grasses grown in full sun or 73%shade *** Rd rates and ambient temperatures on spring days appear to minimize unexplained variance in the data,which would allow researchers to better detect genotypic differences during this season.

关键词： breeding field estimating

Up to date on cholesterol 7 alpha-hydroxylase (CyP7A1) in bile acid synthesis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

liver Research 2020年第2期4卷 47-63页

作者： john y.l.Chiang Jessica M.Ferrell Department of Integrative Medical Sciences Northeast Ohio Medical UniversityRootstownOHUSA

Cholesterol 7 alpha-hydroxylase(CyP7A1,EC1.14)is the first and rate-limiting enzyme in the classic bile acid synthesis *** progress has been made in understanding the transcriptional regulation of CyP7A1 gene expression and the underlying molecular mechanisms of bile acid feedback regulation of CyP7A1 and bile acid synthesis in the last three *** of bile acid-activated receptors and their roles in the regulation of lipid,glucose and energy metabolism have been translated to the development of bile acid-based drug therapies for the treatment of liver-related metabolic diseases such as alcoholic and non-alcoholic fatty liver diseases,liver cirrhosis,diabetes,obesity and hepatocellular *** review will provide an update on the advances in our understanding of the molecular biology and mechanistic insights of the regulation of CyP7A1 in bile acid synthesis in the last 40 years.

关键词： Cholesterol 7 alpha-hydroxylase(CyP7A1) Bile acid metabolism Farnesoid X receptor(FXR) Takeda G protein-coupled receptor 5(TGR5) Bile acid receptors liver metabolism

Geochemistry and mineralogy of beach sediments in the northern Gulf of Mexico,Tamaulipas state,Mexico:implication for provenance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第3期13卷 375-400页

作者： Mayank Shukla Sanjeet K.Verma Mayla A.Ramos-Vázquez john S.Armstrong-Altrin Karla R.Hernández-Martínez Sumit Mishra Vivek P.Malviya Héctor Hernández-Mendoza Posgrado de la Division de Geociencias Aplicadas Instituto Potosino de Investigacion Científica y Tecnologica(IPICYT)Camino a la Presa San José2055San Luis Potosí78216Mexico Division de Geociencias Aplicadas Instituto Potosino de Investigación Científica y Tecnologica(IPICYT)Camino a la Presa San Jose 2055San Luis Potosí78216Mexico Universidad Nacional Autonoma de México Instituto de Ciencias del Mar y LimnologíaUnidad de ProcesosOceanicos y CosterosCiudad UniversitariaCiudad de México 04510Mexico Department of Marine Sciences Bharathidasan UniversityTiruchirappalli620024Tamil NaduIndia Instituto de Geociencias Universidad Nacional Autonoma de MéxicoBoulevard Juriquilla 300176230JuriquillaQueretaroMexico Department of Applied Geology Dr.Harisingh Gour Central UniversitySagar470002Madhya PradeshIndia Instituto de Investigacion de Zonas Desérticas Universidad Autònoma de San Luis PotosíAltair 200CP 78377San LuisS.L.P.Mexico Universidad del Centro de Mexico Capitán Caldera 75CP 78250San LuisS.L.P.Mexico

Geochemical and mineralogical studies were performed in the la Pesca(lP)and Tesoro Altamira(TA)beach sediments,located in the Tamaulipas state,northern Gulf of *** main aim of this study is to infer the weathering history and provenance and to discriminate the tectonic environment of the beach *** sediments are composed of quartz with small amounts of accessory minerals such as plagioclase,calcite,orthoclase,microcline,and *** beach sediments are classified as fine-grained and very well sorted,however lP has coarse skewed and leptokurtic sediments,whereas TA has fine-skewed and very leptokurtic *** chemical index of weathering(CIW’)indicates intense weathering in the source *** quartz grain microtextures in the lP and TA are classified into mechanical,chemical,and mechanical/chemical *** features such as fractures,pits,percussion marks,abrasion fatigue,and V-shaped marks favor high-energy littoral,fluvial,subaqueous-marine,and aeolian *** chemical features indicate solution pits and crystalline overgrowth,which suggests a silica saturated marine *** mechanical/chemical features display adhering particles and elongated depressions suggest formation in a sub-aqueous nearshore marine *** and trace elements-based provenance discrimination diagrams indicate a felsic source derived from the Mesa Central(MC),Sierra Madre Oriental(SMOr)and Oaxaquia *** major and trace element concentrations imply a passive margin setting for the northern Gulf of Mexico,which is consistent with the general geology.

关键词： Beach sediments Geochemistry Mineralogy Provenance Tamaulipas Tectonic setting

Hyperammonemia-induced encephalopathy: A rare devastating complication of bariatric surgery

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

World Journal of Hepatology 2015年第7期7卷 1007-1011页

作者： Michelle l Kromas Omar y Mousa Savio john Department of Anesthesiology SUNY Upstate Medical University Department of Medicine SUNY Upstate Medical University

The clinical manifestations of hyperammonemia are usually easily identifiable to the clinician when associated with liver disease and lead to prompt diagnosis and treatment. However, hyperammonemia-induced encephalopathy is rare in adults in the absence of overt liver disease, thus diagnosis is often delayed or missed leading to potentially life threatening complications. Without proper treatment, such patients can decompensate rapidly with poor outcomes including seizures, coma, and death. Early assessment of plasma ammonia levels in patients with normal hepatic function and characteristic symptoms of encephalopathy can lead to early intervention while investigating the underlying etiology. We describe a patient who presented with a 2-year progression of waxing and waning acute mental status changes after a Roux-en-y gastric bypass surgery. He was found to have elevated ammonia level as well as orotic aciduria; results consistent with a urea cycle disorder. After consulting neurology as well as toxicology, he ultimately improved after dietary protein restriction, sodium benzoate and lactulose therapy. While rare, clinicians should have a high index of suspicion for late onset urea cycle disorders in symptomatic patients presenting with encephalopathy secondary to hyperammonemia.

关键词： Hyperammonemia Urea cycle Bariatricsurgery Encephalopathy Hepatic

Bile acid metabolism and bile acid receptor signaling in metabolic diseases and therapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

liver Research 2021年第3期5卷 103-104页

作者： john y.l.Chiang Stefano Fiorucci Integrative Medical Sciences Northeast Ohio Medical UniversityRootstownOHUSA Department of Medicine and Surgery University of PerugiaPerugiaItaly

Bile acids are nutrient sensors and metabolic regulators that control nutrient intake and gut bacteria growth to regulate glucose,lipid,and energy *** of bile acid meta-bolism causes dysbiosis leading to obesity,diabetes,and liver-related *** acids and their derivatives have emerged as therapeutic drugs for treating liver metabolic and cholestatic dis-eases,type 2 diabetes,and non-alcoholic steatohepatitis(NASH).This special issue covers five emerging topics in bile acid research in metabolic diseases:(i)bile acid synthesis and metabolism in liver metabolic diseases;(ii)bile acid-activated receptors and signaling in liver metabolism and diseases;(iii)gut microbiome in liver path-ophysiology and cholestasis;(iv)bile acid metabolism in metabolic gastric surgery;and(v)cholestasis-associated renal injury,disease,and therapy.

关键词： metabolism bile diseases

Pathogenesis of fatty liver diseases and hepatocellular carcinoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

liver Research 2022年第4期6卷 201-202页

作者： john y.l.Chiang Tiangang li Integrative Medical Sciences Northeast Ohio Medical UniversityRootstownOHUSA Harold Hamm Diabetes Center Department of PhysiologyUniversity of Oklahoma Health Sciences CenterOklahoma CityOKUSA

The prevalence of fatty liver diseases has increased rapidly in recent years to about 25%*** liver diseases are multi-faceted in pathogenesis,disease phenotype,and *** is important to understand disease pathogenesis and mechanism in order to develop effective and safe drug therapy for treating fatty liver *** fatty liver disease(AFlD,or alcohol associ-ated liver disease)and viral hepatitis have been the major causes of liver transplant,liver cancer,and death.

关键词： diseases mechanism. liver

lessons from the past:isotopes of an endangered rail as indicators of underlying change to tidal marsh habitats

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2017年第11期3卷 15-30页

作者： Angela M Merritt Michael l Casazza Cory T Overton john y Takekawa Thomas P Hahn Joshua M Hull u.s.geological survey western ecological research center dixon field office dixoncausa department of animal science university of california davisdaviscausa

Introduction:Tidal marsh systems along the Pacific coast of the United States have experienced substantial stress and loss of area and ecosystem function,which we examined by using the endangered California Ridgway’s Rail,Rallus obsoletus obsoletus(‘rail’)as an indicator of its tidal marsh habitat in the San Francisco *** organized a collection of historical(1885-1940)and modern(2005-2014)rail feathers and analyzed the feather isotope means for delta carbon(δ^(13)C),sulfur(δ^(34)S),and nitrogen(δ^(15)N)by region and time ***:Feather isotopes represented the primary foraging habitat during historical then modern time *** individual nor regional rail feather isotopes suggested freshwater or terrestrial foraging by the *** regions with both historic and modern feather isotopes revealed non-uniform spatial shifts in isotope levels consistent with a marine based food web and significantδ^(15)N ***:Our results supported the rail’s status as a generalist forager and obligate tidal marsh species throughout the historic *** variable isoscape trends generated from feather isotope means illustrated a modern loss of the isotopic homogeneity between regions of historical tidal marsh,which correlated with spatially-explicit habitat alterations such as increasing biological invasions and sewage effluent over ***:These findings have reinforced the importance of tidal marsh conservation in the face of ongoing underlying changes to these important ecosystems.

关键词： Historical change estuary food webs isoscapes isotopes Ridgway’s rail tidal marsh

High Temperature and the Ethylene Antagonist 1-Methylcyclopropene Alter Ethylene Evolution Patterns,Antioxidant Responses,and Boll Growth in Gossypium hirsutum

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2013年第7期4卷 1400-1408页

作者： Eduardo M.Kawakami Derrick M.Oosterhuis john l.snider Toby R.FitzSimons Av.Antonio Teixeira dos Santos RondonópolisBrazil Department of Crop Soiland Environmental SciencesUniversity of Ar-kansasFayettevilleUSA Department of Crop and Soil Sciences University of GeorgiaTiftonUSA

The cotton (Gossypium hirsutum l.) crop experiences high temperatures during flowering and boll development, but information regarding the impact of ethylene inhibition and high temperature on early boll development is limited. The objective of this study was to determine the effects of high temperature and the anti-ethylene compound 1-methylcy-cloprone (1-MCP) on G. hirsutum boll development. Treatments consisted of temperature regime (38/20?C and 30/ 20?C), 1-MCP treatment, and days past anthesis (DPA). High temperature decreased ethylene synthesis by 61% at 2 DPA, and 1-MCP caused a 40% decrease in ethylene production at 1 DPA. Glutathione reductase activity increased under high temperature, whereas superoxide dismutase activity (SOD) and membrane peroxidation (malondialdehyde content) remained unchanged. 1-MCP treatment did not affect GR activity in developing bolls. High temperature and 1-MCP treatment increased the weight of cotton bolls collected 8 DPA with an increase of 0.7 and 1 g, respectively. We propose that increased GR activity in bolls exposed to high temperature may mitigate oxidative damage. Additionally, we conclude that ethylene inhibition (either high temperature or 1-MCP-induced) immediately after flowering (1 or 2 DPA) could potentially have positive impacts on early boll growth.

关键词： Ethylene Glutathione Reductase Gossypium hirsutum High Temperature 1-Methylcyclopropene