Subjects: Biology >> Botany >> Applied botany submitted time 2023-07-26 Cooperative journals: 《广西植物》
Abstract： The ecological stoichiometry of fine root carbon (C), nitrogen (N), and phosphorus (P) is considered to reflect the strategies whereby plants adapt to the soil environment In order to gain an understanding of the seasonal changes in fine root C∶N∶P ratios in different forest types of a karst ecosystem, we measured the C, N, and P contents and ratios of living and dead fine roots in shrubbery and arbor forest vegetation, as well as the influence of abiotic and biotic factors. The results were as follows: (1) That C, N, and P contents in the fine roots of arbor forest vegetation were higher than those of shrubbbery vegetation, thereby indicating that the fine roots of arbor forest trees may by characterized by a stronger absorption and storage of nutrients than those of shrubbbery vegetation. In addition, we established that the contents of C in living fine roots were significantly higher than those in dead fine roots (P < 0.05), whereas in contrast, N and P contents in living fine roots were lower than those in dead fine roots. (2) It was found that the contents of C in the living/dead fine roots of the two forest types were lower during the rainy season than during the dry season. Contrastingly, in shrubbery vegetation, whereas the N and P contents of living fine roots were higher during the rainy season than those in dry season, the opposite pattern was observed for the living fine roots of arbor forest vegetation. During the rainy season, the C∶N, C∶P, and N∶P ratios of living fine roots in shrubbery vegetation were lower than the values obtained during the dry season. Conversely, the C∶N and C∶P ratios of the living/dead fine roots of arbor forest vegetation were higher during the rainy season than in the dry season, whereas the values for the N∶P ratio were lower during the rainy season than during the dry season. The lower rainy season N∶P ratios tend to indicate that plants in shrubbery and arbor forest may be less P restricted during this season. (3) We also found that for both the living and dead fine roots of the two forest types, C contents were higher in plants growing on the upper slopes than in those growing on the middle and lower slopes, whereas the contents of N and P were higher in shrubs and forest trees growing on the lower slopes. Furthermore, the C∶N, C∶P, and N∶P ratios of living and dead fine roots were found to be relatively higher in shrubs growing on the upper slopes. In the case of arbor forest, the C∶N ratios of living and dead fine roots in trees growing on the lower slopes and the C∶P and N∶P ratios in trees growing on the upper slopes were higher than those of trees growing at other elevations, indicating that plants under these two forest types are strongly influenced by P limitation in the upper slopes, but only weakly affected on the middle and lower slopes. (4) Redundancy analysis revealed that forest type, available phosphorus, and season were the main factors influencing the contents and ratios of C, N, and P nutrients in fine roots, and could explain 18.8%, 6.6%, and 6.5% of the observed variation, respectively. These findings indicate that the effects of changes in the N∶P ratio associated with differences in forest type, season, and slope elevation should be taken into consideration when vegetation restoration is promoted, which would contribute to accelerating the restoration of karst ecosystems.
Subjects: Biology >> Botany >> Applied botany submitted time 2023-07-13 Cooperative journals: 《广西植物》
Abstract： In order to explore the effect of enzyme activities of plant root exudates on rhizosphere soil enzyme activities and nutrients in a karst ecosystem, the activities of β-1,4-glucosidase (βG), β-N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and acidic phosphatase (ACP) of fine root exudates and rhizosphere soils in four vegetation restoration stages, which are shrub-grassland, shrubland, shrub-arbor forest and arbor forest, were measured. And, their relationships were also analyzed. The results showed that the four enzyme activities of rhizosphere soils and root exudates were significantly higher in the late stage of vegetation restoration than in the early stage of vegetation restoration. The enzyme activities C:P to N:P ratios of root exudates in arbor forest were significantly higher than those of other three stages, while the two parameters of rhizosphere soils were opposite. Correlation analysis showed that the enzyme activities of root exudates were positively correlated with the corresponding soil enzyme activity. Compared with the enzyme activities of root exudates, the correlation between soil enzyme activity and related nutrients had become significantly stronger. In addition, the activities of βG, NAG and LAP in rhizosphere soils and root exudates were positively correlated with organic carbon (SOC) and total nitrogen (TN) in rhizosphere soil, while the activity of ACP in rhizosphere soils and root exudates were positively correlated with available phosphorus (AP) in rhizosphere soil. The above results indicated that vegetation restoration had a positive effect on increasing activities of root exudates and soils. The enzymes of root exudates were the indispensable supplement for soils, and it played an important role in promoting carbon, nitrogen and phosphorus nutrient cycling. It will be that the regulation of root exudates and its enzyme activities may provide a new perspective for vegetation restoration in karst ecosystem.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-03-30 Cooperative journals: 《广西植物》
Abstract： To explore the effects of land use and ecological restoration on soil enzyme activities and C:N:P ratios in the karst ecosystem, three land use types [disturbed land, pasture grassland, and orchard forest (Loquat)] and four restoration types (evergreen forest, deciduous forest, evergreen-deciduous mixed forest, and natural restoration forest), which are long-term positioning observation experimental plots of the Huanjiang Observation and Research Station for Karst Ecosystems, were selected. We measured the activities of four soil enzymes [β-1,4-glucosidase (βG), β-1,4-N-acetylglucosidase (NAG), leucine aminopeptidase (LAP), and alkaline phosphatase (ALP)], and analyzed the relationship between activities level and the C:N:P ratios and soil-associated physical and chemical factors. The results were as follows: (1) Enzyme activities were higher in the three land use types than in the restoration types. In addition, the activities of the four enzymes, enzymatic N:P, and enzymatic C:P of pasture grassland were higher than those in the other restoration types. The βG and ALP activities in the evergreen-deciduous mixed and deciduous forests were significantly higher than those in the natural restoration and evergreen forest, and NAG activity in the evergreen forest was significantly higher than that in the other three restoration types. The enzymatic N:P ratios of the evergreen-deciduous mixed forests were significantly lower than those in the other restoration types, as was the enzymatic C:P ratio of the deciduous forest. In addition, vector analysis of the enzyme activity measurement ratio showed that all land use and restoration types were limited by P. (2) The activities of the four enzymes were positively correlated with organic C, ammonia N (NH4+-N), and nitrate N (NO3--N), whereas negatively correlated with total P (TP). βG activity was positively correlated with available P (AP) and ALP activity was positively correlated with total N (TN). (3) Redundancy analysis showed that the levels of TP, NH4+-N, NO3--N, and AP explained 38.3%, 9.5%, 9.3%, and 8.0%, respectively, of the changes in soil enzyme activity and C:N:P ratios. Based on these results, the different land use and restoration types in karst areas were shown to generally exist under the limitation of soil P, which implies that the fixation and transformation of P should be the focus of soil quality improvement in the land use development and restoration process. Furthermore, soil enzyme activities, C:P ratios, and AP contents in pasture grassland, evergreen-deciduous mixed forest, and deciduous forest were higher than those in the other land use and restoration types. The result indicates that forage and deciduous plants are important for soil nutrient cycling and should be considered in the process of karst land use and restoration.
Subjects: Biology >> Virology submitted time 2020-02-14
Abstract： Abstract: In 2019, the 2019 novel Coronavirus (2019-nCoV) has caused the pneumonia outbreak in Wuhan (a city of China). In our previous study, the analytical results showed that both 2019-nCoV and SARS coronavirus belongs to Betacoronavirus subgroup B (BB coronavirus), but have large differences. The most important finding was that the alternative translation of Nankai CDS could produce more than 17 putative proteins, which may be responsible for the host adaption. The genotyping of 13 viruses using the 17 putative proteins revealed the high mutation rate and diversity of betacoronavirus. The present study for the first time reported a very important mutation in the Spike (S) proteins of BB coronavirus. By this mutation, 2019-nCoV acquired a cleavage site for furin enzyme, which is not present in the S proteins of all other BB coronavirus (e.g. SARS coronavirus) except the Mouse Hepatitis coronavirus (MHV). This mutation may increase the efficiency of virus infection into cells, making 2019-nCoV has significantly stronger transmissibility than SARS coronavirus. Because of this mutation, the packing mechanism of the 2019-nCoV may be changed to being more similar to those of MHV, HIV, Ebola virus (EBoV) and some avian influenza viruses, other than those of all other BB coronavirus (e.g. SARS coronavirus) except the Mouse Hepatitis coronavirus (MHV). In addition, we unexpectedly found that some avian influenza viruses acquired a cleavage site for furin enzyme by mutation as 2019-nCoV. Further studies of this mutation will help to reveal the stronger transmissibility of 2019-nCoV and lay foundations for vaccine development and drug design of, but not limited to 2019-nCoV.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Zoology submitted time 2018-12-25 Cooperative journals: 《动物营养学报》
Abstract：本研究旨在探讨低蛋白质水平饲粮对生长育肥猪生长性能及肠道菌群的影响。试验选取初始体重为（45.5±3.64） kg的“长×大”二元杂交生长育肥猪140头，随机分为2组，每组5个重复，每个重复14头猪。对照组饲喂蛋白质水平为15.05%的正常蛋白质水平饲粮，试验组喂蛋白质水平为12.97%的低蛋白质水平饲粮。预试期为5 d，正试期为30 d。结果表明：1）低蛋白质水平饲粮对生长育肥猪生长性能无显著影响（P>0.05）。2）低蛋白质水平饲粮可提高生长育肥猪肠道菌群丰富度和多样性。2组试验猪粪便菌群组成在门水平上差异较小，而在属水平上差异较大。物种差异显著性分析显示除了门水平和纲水平，其他分类水平上细菌相对丰度2组间均有显著差异（P＜0.05）。低蛋白质水平饲粮能够显著提高毛螺菌科（Lachnospiraceae）、疣微菌科（Ruminococcaceae）、丁酸弧菌属（Butyrivibrio）和假丁酸弧菌属（Pseudobutyrivibrio）等可以利用碳水化合物和纤维分解产生丁酸的有益菌的相对丰度（P＜0.05），显著降低Paraeggerthella和代尔夫特菌属（Delftia）等易使机体受到感染的细菌相对丰度（P＜0.05）。此外，群落组成差异分析显示低蛋白质水平饲粮组猪相比于正常蛋白质水平饲粮组猪有着不同的肠道微生物区系。由此可见，饲粮蛋白质水平降低2%对生长育肥猪生长性能无不利影响，还可改善肠道菌群平衡，有利于机体健康。
Subjects: Biology >> Zoology submitted time 2018-12-24 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在探讨植物乳杆菌对大肠杆菌感染猪肠道上皮细胞（IPEC-J2细胞）形态、存活和免疫应答的影响。在体外条件下，采用吉姆萨和台盼蓝染色方法检测植物乳杆菌对大肠杆菌感染IPEC-J2细胞形态和存活的影响，并采用实时定量荧光PCR方法研究了其对大肠杆菌感染IPEC-J2细胞免疫应答的影响。结果表明：植物乳杆菌能够缓解大肠杆菌引起的IPEC-J2细胞形态损伤。与大肠杆菌处理组相比，植物乳杆菌与大肠杆菌共同处理可显著或极显著降低细胞死亡率（1、2 h，P<0.01；3 h，P<0.05）。植物乳杆菌可显著抑制大肠杆菌引起的IPEC-J2细胞Toll样模式识别受体2（TLR2）（2、3 h，P<0.01）、Toll样模式识别受体6（TLR6）（2 h，P<0.05；3 h，P<0.01）、NOD样模式识别受体2（NOD2）（1 h，P<0.05；2 h，P<0.01）及炎症因子白细胞介素-6（IL-6）（2、3 h，P<0.01）、白细胞介素-8（IL-8）（2、3 h，P<0.01）mRNA的过表达（P<0.05），还可促进IPEC-J2细胞NOD样模式识别受体1（NOD1）mRNA的表达（2 h，P<0.05；3 h，P<0.01）。结果提示，植物乳杆菌能够缓解大肠杆菌引起的IPEC-J2细胞形态损伤及死亡，并可通过调节模式识别受体TLR2、TLR6和NOD2 mRNA的表达缓解大肠杆菌引起的细胞炎症因子IL-6、IL-8 mRNA的过表达。
Subjects: Biology >> Zoology submitted time 2018-12-20 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在探讨饲粮中添加干酪乳杆菌对北京黑猪保育阶段生长性能及肠道菌群的影响。选择（35±2）日龄、体重（7.53±0.21） kg的北京黑猪仔猪120头，随机分成3组，分别为对照组、干酪乳杆菌组和金霉素组，每组4个重复，每个重复10头。对照组试验猪饲喂基础饲粮（不添加干酪乳杆菌和金霉素）；干酪乳杆菌组试验猪饲喂在基础饲粮中添加干酪乳杆菌活菌冻干制剂的饲料，每千克饲料中有效活菌数在4.0×109 CFU；金霉素组试验猪饲喂在基础饲粮中添加金霉素预混剂的饲料，每千克饲料中含金霉素75 mg。试验期30 d，在试验第28天时采集新鲜粪样，用于16S rRNA的V3～V4区测序。结果显示：1）与对照组相比，干酪乳杆菌组和金霉素组的平均日增重分别提高12.71%（P0.05)。2）通过对粪样菌群ACE指数、Chao1指数、Shannon指数和Simpson指数进行分析，发现干酪乳杆菌组肠道菌群丰富度和多样性均高于对照组和金霉素组。3）3组粪样中共含有17个菌门，206个菌属，对照组、干酪乳杆菌组和金霉素组粪样中分别含有198、200和197个菌属。由此可见，在北京黑猪保育阶段饲粮中添加干酪乳杆菌可改善仔猪肠道内菌群结构，进而提高生长性能。
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在研究饲粮铁添加水平对60～90日龄新西兰肉兔生长性能、屠宰性能及血液指标的影响。试验选取104只53日龄体重相近新西兰肉兔，随机分成4个组，每组26个重复，每个重复1只兔。对照组饲喂基础饲粮，试验组分别在基础饲粮中添加50、100、200 mg/kg铁，铁添加形式为七水硫酸亚铁（FeSO4.7H2O），纯度为98%。预试期7 d，正试期30 d。结果表明：1）饲粮铁添加水平对60～90日龄新西兰肉兔平均日增重（ADG）和料重比（F/G）有影响显著（P＜0.05），对平均日采食量（ADFI）无显著影响（P＞0.05）。随着饲粮铁添加水平的增加，ADG先增加后降低，F/G先降低后增加；当饲粮铁添加水平为100 mg/kg时，ADG最高，F/G最低。2）饲粮铁添加水平对60～90日龄新西兰肉兔全净膛屠宰率和半净膛屠宰率有显著影响（P＜0.05），随着饲粮铁添加水平的增加全净膛屠宰率和半净膛屠宰率先增加后降低，当饲粮铁添加水平为50 mg/kg时最高。3）饲粮铁添加水平对60～90日龄新西兰肉兔肝脏指数无显著影响（P＞0.05），对肾脏指数和脾脏指数有显著影响（P0.05）；饲粮铁添加水平对血小板分布宽度（PDW）、平均血小板体积（MPV）、血小板大细胞比率（P-LCR）有显著影响（P＜0.05）。综合本试验测定指标，60～90日龄新西兰肉兔饲粮中适宜的铁添加水平为50～100 mg/kg。
Subjects: Biology >> Bioengineering submitted time 2017-07-24 Cooperative journals: 《中国生物工程杂志》
Abstract：对香豆酸（p-coumaric acid）作为苯丙素类物质、芪类物质以及黄酮类物质的重要前体化合物，在生物医药、化妆品以及食品工业中均有广泛的应用价值。以酿酒酵母作为底盘菌株，利用合成生物学原理构建一株高产对香豆酸的人工酵母细胞。通过对比不同拷贝数的酪氨酸解氨酶（Tyrosine ammonia lyase, TAL）合成的对香豆酸产量，发现随着基因拷贝数的增加对香豆酸的产量也相应提高，高拷贝数的TAL有利于对香豆酸的积累；同时对酪氨酸的负反馈调控基因进行氨基酸定点突变得到ARO4K229L和ARO7G141S，利用delta位点将突变后的基因整合至酵母基因组，并挑取24株构建成功的酵母细胞进行发酵验证，发现菌株最高产量与最低产量相差28.87 mg/L；为了进一步增加对香豆酸的代谢通量，本研究对生成芳香醇类物质的旁路基因ARO10和PDC5进行敲除，发现同时敲除两个基因的菌株对香豆酸的产量最高，是敲除前产量的2.05倍（从42.71 mg/L到87.56 mg/L）；此外，通过设计前体酪氨酸的梯度添加实验，发现当添加1 mM的酪氨酸时，对香豆酸产量达到峰值174.57±0.30 mg/L，相较于未添加时提高了将近一倍。本研究通过运用合成生物学原理在酿酒酵母中实现了对香豆酸的高产，为后续的芪类化合物和黄酮类化合物生物合成奠定了基础。
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