Research Progress of Grassland Feed-animal Balance at Home and Abroad

Feed-animal balance is the key technique on the grassland ecosystem management,and attracts widespread attention in the world.Many studies have been conducted by former researchers,and most of their efforts were intended to keep the balance of feed-animal.However,there are still much more issue needed to be studied in details on the face of grassland degeneration and animal husbandry sustainable development.The author analyzed the feed-animal balance research progress,including the concept of stocking rate and its practical management techniques,especially on the stocking rate calculation methods.In addition,the social and economy effects on feed-animal balance were also discussed during the progress of improving the development of pastoral economy.In order to achieve feed-animal balance more effectively,it was concluded that the focus must be shift from only on animal number to the grassland quality,and it's necessary to strengthen market tax control.

国产高压辊磨机在有色矿山的应用及分析

高压辊磨机是一种节能性强,高效的辊磨技术形式,当前在国内外都得到广泛的重视。本文主要对国产高压辊磨机的工作原理,技术特点等进行分析,并对高压辊磨机在有色矿山的应用进行阐述。

Boosting wheat functional genomics via an indexed EMS mutant library of KN9204

A better understanding of wheat functional genomics can improve targeted breeding for better agronomic traits and environmental adaptation.However,the lack of gene-indexed mutants and the low transformation efficiency of wheat limit in-depth gene functional studies and genetic manipulation for breeding.In this study,we created a library for KN9204,a popular wheat variety in northern China,with a reference genome,transcriptome,and epigenome of different tissues,using ethyl methyl sulfonate(EMS)mutagenesis.This library contains a vast developmental diversity of critical tissues and transition stages.Exome capture sequencing of 2090 mutant lines using KN9204 genome-designed probes revealed that 98.79%of coding genes had mutations,and each line had an average of 1383 EMS-type SNPs.We identified new allelic variations for crucial agronomic trait-related genes such as Rht-D1,Q,TaTB1,and WFZP.We tested 100 lines with severemutations in 80 NAC transcription factors(TFs)under drought and salinity stress and identified 13 lines with altered sensitivity.Further analysis of three lines using transcriptome and chromatin accessibility data revealed hundreds of direct NAC targets with altered transcription patterns under salt or drought stress,including SNAC1,DREB2B,CML16,and ZFP182,factors known to respond to abiotic stress.Thus,we have generated and indexed a KN9204 EMS mutant library that can facilitate functional genomics research and offer resources for genetic manipulation of wheat.

中国北方温带草原植被恢复的氮限制

围栏禁牧被认为是退化草原植被恢复的有效手段。在植被的恢复过程中,植物需要从土壤中吸收更多的氮。氮素也是中国北方温带草原植被生长的一个主要限制因素。目前尚不清楚该地区的土壤氮素供应是否能够支持长期的植被恢复。本研究在植被的生长季期间对我国北方7个温带草原进行了野外调查。其中,围栏外侧草地保持持续放牧状态,围栏内侧草地保持完全禁牧状态。研究结果表明,禁牧显著提高了草地地上生物量、物种丰富度和香农-维纳多样性指数,其分别提高了126.2%、42.6%和18.8%。禁牧使土壤硝态氮和总无机氮浓度分别降低了51.9%和21.0%,这表明生长季氮素供应与植物需求可能存在错配现象。同时,围封草地地上生物量、物种丰富度和香农-维纳多样性指数与豆科植物群落优势度呈正相关。这些结果表明,温带草原植被恢复受土壤无机氮限制。群落中豆科植物的生物固氮可能缓解植被恢复的氮限制。

退化草原植被免耕补播修复理论与实践

退化草原植被修复是当前我国草原生态治理最紧迫的任务,免耕补播是退化草原植被修复关键技术,其意义是在不破坏或少破坏草原植被的条件下,通过补播适宜的优良草种,提高退化草原生产力和物种多样性.该技术与其他补播改良方式的不同之处在于免耕,难点也在于如何在不扰动或少扰动原生植被的前提下成功补播修复草原,其关键技术主要包括补播物种的选择、补播技术和补播后草原管理.本文针对上述技术难点,提出补播物种选择假说、免耕补播的空斑原则和补播后亚顶级群落管理模型,根据《天然草地退化、沙化、盐渍化的分级指标》国家标准,制定了针对不同退化程度草原的免耕补播技术方案;依据全国草原气候和土壤等条件,提出了全国草原实施免耕补播修复的规划,对我国草原生态文明建设具有重大意义.

宏基因组来源新过水解酶的分子克隆与酶学特性

旨在获得具有氯化功能的过水解酶,拓展过水解酶资源,为其工业应用奠定基础。以唐河某造纸厂污泥为材料构建宏基因组文库,通过活性筛选获得一个细菌过水解酶Per822。使用大肠杆菌异源表达Per822,研究纯化后的重组蛋白酶学性质并检测了生成过乙酸的能力。测序结果显示per822编码一个含273个氨基酸的蛋白。Per822是典型的多功能酶代表,分别具有过氧化物酶、卤代酶和酯酶的活性。Per822过水解氯化单氯二甲酮的最适反应pH为4.5,在pH3.5–8.0范围内酶活性稳定。最适反应温度是55℃,在70℃以下酶活性稳定且氯化活性能够被Fe2+激活。以乙酸乙酯为共底物Per822显示出较强的产过乙酸能力。重组Per822的高可溶性表达、催化多功能性、较强的产过乙酸能力使得Per822在有机合成、废水处理、杀菌、生物质预处理等方面有着潜在的应用价值。

Hes1 Knockdown Exacerbates Ischemic Stroke Following tMCAO by Increasing ER Stress-Dependent Apoptosis via the PERK/ eIF2a/ATF4/CHOP Signaling Pathway

Apoptosis induced by endoplasmic reticulum(ER)stress plays a crucial role in mediating brain damage after ischemic stroke.Recently,Hes1(hairy and enhancer of split 1)has been implicated in the regulation of ER stress,but whether it plays a functional role after ischemic stroke and the underlying mechanism remain unclear.In this study,using a mouse model of ischemic stroke via transient middle cerebral artery occlusion(tMCAO),we found that Hes1 was induced following brain injury,and that siRNA-mediated knockdown of Hes1 increased the cerebral infarction and worsened the neurological outcome,suggesting that Hes1 knockdown exacerbates ischemic stroke.In addition,mechanistically,Hes1 knockdown promoted apoptosis and activated the PERK/eIF2a/ATF4/CHOP signaling pathway after tMCAO.These results suggest that Hes1 knockdown promotes ER stress-induced apoptosis.Furthermore,inhibition of PERK with the specific inhibitor GSK2606414 markedly attenuated the Hes1 knockdown-induced apoptosis and the increased cerebral infarction as well as the worsened neurological outcome following tMCAO,implying that the protection of Hes1 against ischemic stroke is associated with the amelioration of ER stress via modulating the PERK/eIF2a/ATF4/CHOP signaling pathway.Taken together,these results unveil the detrimental role of Hes1 knockdown after ischemic stroke and further relate it to the regulation of ER stress-induced apoptosis,thus highlighting the importance of targeting ER stress in the treatment of ischemic stroke.

Efficacy and Safety of All-oral Emitasvir and Sofosbuvir in Patients with Genotype 1b HCV Infections without Cirrhosis

Publications>Journals>Journal of Clinical and Translational Hepatology>Article Full Text ORIGINAL ARTICLE OPEN ACCESS Efficacy and Safety of All-oral Emitasvir and Sofosbuvir in Patients with Genotype 1b HCV Infections without Cirrhosis Huiying Rao1,Xingxiang Yang2,Youwen Tan3,Qin Ning4,Daokun Yang5,Jiefei Wang6,Yongfeng Yang7,Sujun Zheng8,Dongliang Yang9,Jinlin Hou10,Qing Xie11,Caiyan Zhao12,Lunli Zhang13,Xiaorong Mao14,Tong Sun15,Lang Bai16,Fuchun Zhang17,Jinglan Jin18,Yingren Zhao19,Maorong Wang20,Wen Xie21,Yingjie Ma22,Jun Quan23,Xuebing Yan24,Ping An25,Feng Lin26,Jidong Jia27,Xiaoxuan Hu28,Zuojiong Gong29,Jie Wu30,Yongping Chen31,Zhansheng Jia32,Minghua Lin33,Guiqiang Wang34,Yueyong Zhu35,Yingjun Zhang*,36,Hongming Xie36,Lin Luo36,Qingyun Ren36,Rui Huang1 and Lai Wei*,37 Author information Journal of Clinical and Translational Hepatology 2020;8(3):255-261DOI:10.14218/JCTH.2020.00031 Abstract Background and Aims:Emitasvir is a new type of hepatitis C virus(HCV)nonstructural protein 5A(NS5A)inhibitor,and the data of phase 2 trial has shown emitasvir-sofosbuvir to have good safety and tolerance.We conducted this phase 3 trial to further verify the efficacy and safety.Methods:We evaluated the antiviral activity and safety of a 12-week regimen of emitasvir phosphate(100 mg)combined with sofosbuvir(400 mg)once daily in non-cirrhotic patients with genotype 1 HCV infection.The primary endpoint was a sustained virological response at 12 weeks(SVR12)after the end of treatment.Results:Of the 362 patients enrolled in the trial,39.8%were male,99.2%had HCV genotype 1b,0.8%had genotype 1a and 79.8%were treatment-naïve.The average age was 47.2 years.All patients completed the treatment and follow-up.All 3 patients with genotype 1a achieved SVR.Two genotype 1b treatment-naïve patients experienced virologic relapse.The rate of SVR12 was 99.7%(358/359),and SVR24 was 99.4%(357/359)in genotype 1b.Overall,36.2%had resistance-associated substitutions(RASs)in NS5A and 98.3%had RASs in NS5B at baseline.The RASs at baseline had no effect on the rates of response.Serious adverse events were reported in 16 patients and were not related to emitasvir-sofosbuvir.Most adverse events did not require therapy.Conclusions:The 12 weeks of treatment with emitasvir-sofosbuvir was a highly efficient and safe treatment for a wide range of patients with HCV genotype 1b infection without cirrhosis,who had not been treated or who had been treated with interferon-based regimen previously.

Two new steroidal tetraglycosides from the rhizomes of Smilacina atropurpurea

Smilacina atropurpurea(family Convallariaceae)is a perennial herb used medicinally for the trea tment of lung ailments,rheumatism,menstrual disorders,and cuts and bruises,by the local people of its growing areas in southwest China.The tender aerial part has also been used as a wild vegetable by Lisu,Naxi and Tibetan people.Chemical analysis of the rhizomes of this plant has allowed us to isolate two new minor steroidal tetraglycosides,specifically atropurosides H(1) and I(2),by repeated column chromatography over silica gel and reversed phase silica.The structures were determined to be(25R,S)-12β-hydroxy-spirost-5-ene-3β-yl-O-β-D-glucopyranosy1-(1→2)-[β-D-xylopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside(1)and(25S)-5α-spirost-17α-hydroxy-3β-yl-O-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopy-ranosyl-(1→4)-β-D-galacto pyranoside(2),respectively,on the basis of detailed spectroscopic analysis including ID and 2D NM R techniques.

Sustainable management of Chinese grasslands—issues and knowledge

China has almost 400 Mhm^2 of grasslands,90% of which is considered degraded to varying degrees,on which 16 million herders depend for their livelihoods and many more indirectly, along the value-adding chain.Since 1950, average stocking rates across China have increased 4-fold. National policies have focused over recent decades on finding ways to rehabilitate the degraded grasslands, to sustain livestock production from them, and to improve the livelihoods of herder households, who are among the poorest people in China. A large collaborative program commenced in the early 2000 s to help find solutions to the sustainable management of grasslands.This paper summarizes key findings of many research projects, identifies where knowledge is weak and argues that the successful rehabilitation of grasslands will also require policies that provide incentives and support for herders as they move from a focus on survival to a focus on production of higher quality products, for which consumers are increasingly willing to pay. A key focus is to emphasize the improvement of animal production per head. When this is done, it naturally leads to lower stocking rates, which in turn provides the opportunities for grasslands to recover. Across a range of experiments, farm demonstrations and analyses using models, in Inner Mongolia and Gansu, a consistent result has been that a 50% reduction in stocking rates, improves net household income and starts the process of grassland rehabilitation.Rather than focusing on stocking rates, better management of grasslands could be achieved by maintaining the grasslands above critical values for herbage mass, values that help optimize botanical composition, reduce soil erosion, optimize animal growth rates and aid ecosystem functions. Managing to critical values for herbage mass is likely to be more effective than efforts to calculate sustainable stocking rates. An early summer rest is valuable for aiding grassland rehabilitation and summer productivity, but a total grazing ban(typically for 5 years)may not achieve its aims as evidence shows it may take 10–15 years to achieve a better grassland state. Lessdesirable plant species often increase in degraded grasslands that are rested and grazing can help manage those species. Surveys of herders indicate they have very mixed views on the benefits of total grazing bans that are unlikely to rehabilitate grasslands to an ideal botanical composition.The current objective is to work with grasslands that herders now have and optimize the existing composition.Grazing grasslands in winter results primarily in weight loss by animals and there is now evidence of how winter grazing reduces grassland growth in the next summer. It is better to keep animals in well-built sheds and feed them better, improved feeding through the cold months is required. In addition to the application of results from national programs designed to improve grasslands, it will be important to train herders as they move from survival to production, to foster the development of better markets for their livestock products, to devise better financial support for herder businesses and to revise land tenure arrangements so that herders can expand the area of land they graze on better terms than apply at present.

BENDING OF ORTHOTROPIC SANDWICH PLATES WITH A FUNCTIONALLY GRADED CORE SUBJECTED TO DISTRIBUTED LOADINGS

Based on the Reissner assumptions, this paper is concerned with the bending analy- sis of simply supported sandwich plates with functionally graded core and orthotropic face sheets subjected to transverse distributed loadings. First, the expressions of the displacements, stresses and internal forces of the sandwich plate are presented according to the constitutive relations and stress states of the core and face sheets. Then, the solutions of bending equilibrium equa- tions are derived by expanding the deflection w, transverse shearing forces Q~ and Qv with double trigonometric series that satisfy the simply supported boundary conditions. Finally, the proposed solution is validated by comparing the results with available elasticity solutions for a square sand- wich plate with an isotropie core and finite element simulations for one with functionally graded core. The Young＇s modulus of the functionally graded core is assumed to be graded by a power law distribution of volume fractions of the constituents, and the Poisson＇s ratio is held constant. And the effects of the core＇s top-bottom Young＇s modulus ratio A and volume fraction exponent no on the variation of the displacements of the functionally graded sandwich plate are also examined.

Grassland management practices in Chinese steppes impact productivity, diversity and the relationship

Grasslands are crucial parts of the terrestrial ecosystem, with an extremely high differentiation of productivity and diversity across spatial scales and land use patterns. The practices employed to manage grassland,such as grazing, haymaking, fertilization or reseeding, can improve the grassland condition. This study focuses on the changes in productivity and diversity and the relationship between them as affected by management practices.Productivity and diversity have unequivocally been altered in response to different management practices. When grazing intensity of a typical steppe increased from 1.5 to 9 sheep per hectare, both productivity and diversity declined.Higher grazing intensity(6 to 9 sheep per hectare)accelerated loss of diversity because of lower productivity.Productivity was significantly improved but diversity was lost by fertilizing. N fertilization also reduced the sensitivity of diversity to productivity. A similar response was found in mown grassland with increased productivity and diversity but their relationship was negatively affected.Mowing also slowed down the decline in diversity as productivity increased. Reseeding purple-flowered alfalfa led to an increased diversity, while yellow-flowered alfalfa increased productivity significantly. The negative productivity-diversity relationship was transformed to a positive one by reseeding alfalfa. These results enhance understanding of how productivity, diversity and their relationships change in response to altered grassland management practices, and support an integrated approach for improving both productivity and diversity.

Editorial

It is our honor to offer you this inaugural issue of Grassland Research.Grassland is the largest terrestrial ecosystem on the earth.It produces an array of goods,including food,feed,fiber,and fuel,and ecosystem services as varied as weather amelioration,carbon sequestration,biodiversity enhancement,soil conservation,recreation,and the maintenance of the atmospheric composition.Historically,grassland has played an essential role in the development of civilization.Humans would likely be very different without their coevolution with grassland.The saying“All flesh is grass”indicates partially the relationship between humans and grassland.Currently,the world is facing many serious challenges and problems,including global warming,food shortages,water scarcity,land degradation and desertification,soil erosion,flooding,and other illnesses.These challenges will become more severe in the coming years,making the role of grasslands in our agricultural and ecological systems ever more important.Of course,grasslands cannot solve all these problems,but they can play a positive role in our future welfare.The development and application of science and technology,and the support of policy,will ensure that grasslands play a significant role in solving these problems.It is the obligation of grassland scientists together with other stakeholders to redouble our efforts to understand and improve grasslands.