营养学中氨基酸平衡的度量

本文基于聚类分析理论,提出了失衡度(IBD)这一新的化学指数,借以定量地研究蛋白质营养中的氨基酸平衡问题。当样品中氨基酸完全平衡时,IBD取值为零;而当其氨基酸平衡最差时。IBD取值为1。IBD的氨基酸增量模型为非对称最大值式;且IBD与变异系数(CV)之间有着密切的关系。通过IBD这一指数,可以对各种单一饲料的蛋白质营养价值加以分类列等;通过计算两种以上饲料蛋白质混合物的IBD,可以从理论上预测它们之间是否互补,以及何时发生最佳互补关系。若引申IBD的概念框架,还可以用来研究其它养分之间的平衡关系,并有助于实现计算机配方过程的自动鉴别和筛选。     

Effects of intrauterine growth restriction during late pregnancy on the ovine fetal renal function and antioxidant capacity

This study investigated the effects of intrauterine growth restriction during late pregnancy on the ovine fetal renal function and renal antioxidant capacity. Eighteen ewes pregnant were randomly divided into control group (CG, ad libitum, 0.67 MJ ME·BW^−0.75·day⁻¹, n = 6), restricted group 1 (RG1, 0.18 MJ ME·BW^−0.75·day⁻¹, n = 6), and restricted group 2 (RG2, 0.33 MJ ME·BW^−0.75·day⁻¹, n = 6). At 140 days, the fetal blood, allantoic fluid and kidney tissue were collected to determinate fetal renal function and renal antioxidant capacity. The results showed that the fetal weight, kidney weight, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), aquaporin-2 (AQP-2) and aquaporin-3 (AQP-3), and total antioxidant capacity (T-AOC) in RG1 group were decreased compared with the CG (P < 0.05), but the contents of β2-Microglobulin (β 2-MG), cystatin C (Cys-C), filtered sodium excretion fraction (FENa), malondialdehyde (MDA), and hydroxyl radical (OH) in RG1 group were increased (P < 0.05). The impaired ovine fetal renal growth, antioxidant imbalance and dysfunction of glomerulus ultrafiltration, and the renal tubules reabsorption were induced by maternal malnutrition during late pregnancy.     

基于网络药理学及分子对接技术研究黄芪调控仔猪肠道菌群失调性腹泻的作用

【目的】基于网络药理学及分子对接技术研究黄芪调控仔猪肠道菌群失调性腹泻的有效活性成分及其作用机制。【方法】从TCMSP数据库搜集黄芪中药化合物成分,并获取其潜在靶点。利用GeneCards和OMIM数据库搜集肠道菌群失调性腹泻(flora imbalance diarrhea)的作用靶点,将两者预测的潜在作用靶点进行映射,获得共同作用靶点。运用STRING数据库构建靶点蛋白-蛋白相互作用(PPI)关系,用Cytoscape_3.8.0软件对其网络进行拓扑分析,用DAVID数据库对共同作用靶点进行富集分析,用AutoDuck_4.2.6软件对其核心成分与核心靶点进行分子对接。【结果】黄芪含有11个调控仔猪肠道菌群失调性腹泻核心成分,其对应靶点基因65个,疾病靶点854个,交集靶点25个。PPI网络中显示肿瘤坏死因子(TNF)、转录因子AP-1(JUN)、半胱氨酸蛋白酶-3(CASP3)、白细胞介素-6(IL6)、NF-κB抑制剂α(NFKBIA)、IL1B、IL10、细胞肿瘤抗原p53(TP53)、过氧化物酶体增殖物激活受体γ(PPARG)、C-C基序趋化因子2(CCL2)为关键靶点。GO功能和KEGG通路富集分析发现,黄芪有效成分主要通过美国锥虫病、炎症性肠病、阿米巴病、细胞因子-细胞因子受体相互作用、A型流感、疟疾、T细胞受体信号通路、沙门菌感染等信号通路参与转录调控、免疫反应、细胞对脂多糖的反应等生物过程。分子对接结果显示,槲皮素、山奈酚、芒柄花素等核心成分与TNF、IL1B等关键靶点结合紧密,亲和力较好。【结论】黄芪可能通过槲皮素、山奈酚、芒柄花素等主要活性成分作用于TNF、IL1B等靶点,通过参与美国锥虫病、炎症性肠病、疟疾、T细胞受体信号通路、沙门菌感染等信号通路进而治疗仔猪肠道菌群失调性腹泻。     

IQGAP1 is overexpressed and interacts with ERK in human myeloma cells

AIM:To explore the role of IQ motif-containing GTPase-activating protein 1 (IQGAP1) in the cell proliferation of multiple myeloma and its mechanism. METHODS:RT-PCR and Western blotting were performed to detect the expression of IQGAP1 in human myeloma cell lines RPMI8226 and U266. shRNA-expressing plasmids were used to transfect into RPMI8226 cells to knock down the expression of IQGAP1. MTT assay was used to examine the proliferation of RPMI8226-shIQGAP1 (clone 1) cells, RPMI8226-shRNA negative control cells and un-transfected RPMI8226 cells with or without VEGF/IL-6 treatment. The protein levels of p-ERK1/2, ERK1/2, AKT, p-AKT, STAT3 and p-STAT3 in RPMI8226-shIQGAP1 (clone 1) cells, RPMI8226-shRNA negative control cells and un-transfected RPMI8226 cells were measured by Western blotting. The interaction between IQGAP1 and ERK was determined by the method of co-immunoprecipitation. RESULTS:IQGAP1 was overexpressed in human myeloma cell lines RPMI8226 and U266 as compared with normal lymphocytes. Transfection with shRNA targeting to IQGAP1 decreased the expression levels of IQGAP1 in RPMI8226 cells. The proliferation of RPMI8226 cells decreased when IQGAP1 was knocked down by shRNA with or without VEGF/IL-6 treatment. IQGAP1 affected the proliferation of RPMI8226 cells by regulation of MAP kinase (ERK1/2) pathway. The level of p-ERK1/2 in RPMI8226-shIQGAP1 (clone 1) cells decreased by 70.2% as compared with RPMI8226-shRNA negative control cells and un-transfected RPMI8226 cells. The interaction between IQGAP1 and ERK in RPMI8226 cells was observed. CONCLUSION: IQGAP1 plays an important role in the cell proliferation of multiple myeloma via MAP kinase (ERK) pathway.     

Histamine receptor antagonist prevent and ameliorate airway remodeling and acid-base imbalance in asthma of guinea pig

AIM:To investigate the effect of histamine receptor antagonist on airway remodeling and acid-base imbalance in asthma of guinea pig. METHODS:Guinea pigs were divided into 5 groups: the normal control group, the asthma model group, the continued asthma model group, histamine group and histamine receptor antagonist group. For each group, the content of histamine, Na+, Cl-, PaO2, PaCO2, pH, AB, SB in serum, and thickness of airway mucosa and smooth muscle cell layer were measured and compared with each other. RESULTS:(1) According to the content of histamine in serum and thickness of airway mucosa and smooth muscle, the order was: the histamine group>continued asthma model group>the asthma model group>the normal control group (P<0.01), and the histamine receptor antagonist groupthe continued asthma model group (P<0.01), but for PaCO2, the order was conversed. Airway remodeling, increase in histamine in serum, respiratory acidosis and metabolic acidosis in asthmatic guinea pig were observed. Exogenous histamine accentuated the change, however, histamine receptor antagonist attenuated it. CONCLUSION:Histamine may take part in the airway remodeling of asthma. Histamine receptor antagonist can prevent and ameliorate airway remodeling and acid-base imbalance in asthma of guinea pig.     

河南省县域耕地面积的时空演变

采用地理集中指数、不平衡指数等统计指标,在软件ArcGIS 9.0的帮助下,探索了河南省县域耕地面积和人均耕地面积在1994,1999和2004年的空间格局,不同时期两者变化的数量和速度及其空间分异特征等。研究结果表明:(1)河南省县域耕地面积分布呈现出东南部相对较多,西北部相对较少的空间格局。(2)在研究前期(1994—1999年),耕地面积增加的县级行政区划在空间和数量上均比较集中,耕地减少的县级行政区划在空间和数量上均比较分散。而在研究后期(1999—2004年)则出现了相反的发展态势。(3)县域耕地面积变化率与地形地貌等因素有关。(4)人均耕地面积相对较多的地区主要集中在京广铁路沿线、南阳市和三门峡市两地区的部分县级区划单位单位。(5)河南省县域人均耕地面积变化量总体上呈现出"南多北少"的空间格局。(6)河南省县域人均耕地变化率较高的地区主要分布在豫西南地区,三门峡市和豫北地区的部分县级区划单位人均耕地面积变化率则相对较低。     

Identifying nutrient imbalances in pomegranate (Cv. Bhagwa) at different phonological stages by the diagnosis and recommendation integrated system

The diagnosis and recommendation integrated system (DRIS) approach was used to interpret nutrient analyses of leaf tissues from pomegranate cv. Bhagwa orchards grown in southwestern Maharashtra, India. The DRIS norms were established for three growth stages,viz. 50% flowering, fruit development and first harvesting of pomegranate. Various nutrient ratios were obtained from high-yielding population and were used to compute DRIS indices for diagnosing nutrient imbalances and their order of limitation to yield. Nutrient sufficiency ranges at 50% flowering derived from DRIS norms were 1.32–2.15% nitrogen (N), 0.18–0.24% phosphorus (P), 1.29–1.99% potassium (K), 0.64–1.20% calcium (Ca), 0.23–0.45% magnesium (Mg), 0.16–0.26% sulfur (S), 103.04–149.12 mg kg^?1 iron (Fe), 39.60–72.85 mg kg^?1 manganese (Mn), 15.99–26.10 mg kg^?1 zinc (Zn), 6.16–9.32 mg kg^?1 copper (Cu), 23.38–39.88 mg kg^?1 boron (B) and 0.29–0.47 mg kg^?1 molybdenum (Mo). Similarly, the sufficiency range at fruit development and first harvesting was developed for computing DRIS indices. The requirement of Fe, Mg, S, Zn and N by the pomegranate plant was higher at 50% flowering and fruit development stages. According to these DRIS-derived indices, 87.85, 73.83, 70.09, 69.16 and 65.42% orchards were deficient in Fe, S, Mg, Zn, and N, respectively, at 50% flowering, while 70.03, 66.36, 63.55, 61.68, and 68.22% orchards were found to be deficient in respective nutrients during the fruit development stage.     

Nitrogen nutrition and adaptation of glycophytes to saline environment: a review

Relations between nitrogen (N) nutrition and salinity tolerance in plants are multifaceted and varies significantly depending on many soil and plant factors. Saline environment might experience an N dilemma due to the opposing effects of salt ions on N uptake, translocation and metabolism within the plant body. Adequate regulation of N under saline conditions can be a promising approach to alleviate salinity’s effects on plants by ameliorating ion toxicity and nutrient imbalances through its impacts on the uptake and redistribution of salt ions within the plant. Certain N-containing compounds including proline, glycine betaine, proteins and polyamines help the plants to tolerate salinity through their involvement in improving water uptake and water use efficiency, membrane integrity, enzyme activation, hormonal balance, chlorophyll synthesis, stimulation of photosystems and CO₂ assimilation under salinity stress. Nitrogen, particularly NO₃^? represents a stress signal that triggers the activation of antioxidant enzymes to protect the plants against salinity-induced oxidative damage. Furthermore, the source/form of N application can affect not only N-interactions but also the behavior of other nutrients in stress environment. The present review deals with N-salinity relations in plants, particularly glycophytes, emphasizing on N-induced mechanisms which can improve plant adaptation to saline environment.     

Coping with imbalanced data problem in digital mapping of soil classes

An unsolved problem in the digital mapping of categorical soil variables and soil types is the imbalanced number of observations, which leads to reduced accuracy and the loss of the minority class (the class with a significantly lower number of observations compared to other classes) in the final map. So far, synthetic over- and under-sampling techniques have been explored in soil science; however, more efficient approaches that do not have the drawbacks of these techniques and guarantee retention of the minority classes in the produced map are essentially required. Such approaches suggested in the present study for digital mapping of soil classes include machine learning models of ensemble gradient boosting, cost-sensitive learning and one-class classification (OCC) of the minority class combined with multi-class classification. In this regard, extreme gradient boosting (XGB) as an ensemble gradient learner, a cost-sensitive decision tree (CSDT) within the C5.0 algorithm, and a one-class support vector machine combined with multi-class classification (OCCM) were investigated to map eight soil great groups with a naturally imbalanced frequency of observations in northwest Iran. A total of 453 profile data points were used for mapping the soil great groups of the study area. A data split was done manually for each class separately, which resulted in an overall 70% of the data for calibration and 30% for validation. The bootstrapping approach of calibration (with 10 runs) was performed to produce multiple maps for each model. The 10 bootstraps were evaluated against the hold-out validation dataset. The average values of accuracy measures, including Kappa (K), overall accuracy (OA), producer's accuracy (PA) and user's accuracy (UA), were explored. In addition, the results of this study were compared with a previous study in the same area, in which resampling techniques were used to deal with imbalanced data for digital soil class mapping. The findings show that all three suggested methods can deal well with the imbalanced classification problem, with OCCM showing the highest K (= 0.76) and OA (= 82) in the validation stage. Also, this model can guarantee the retention of the minority classes in the final map. Comparing the present approaches with the previous study approach demonstrates that the three newly suggested methods can remarkably increase both overall and individual class accuracy for mapping.     

Predicting Rice Yield Under Salinity Stress Using K/Na Ratio Variable in Plant Tissue

Estimation of yield reduction in crop caused by the salinity stress is mostly based on variations of soil electrical conductivity and the severity of water stress. Crop response curves to salinity were developed without considering ion toxicity and nutritional imbalance in the plant. The objective of this study was to explore the possibility of using the ratio of the concentration of potassium by sodium in rice leaf (leaf-K/Na) to predict yield under the salinity stress. The rice (Oryza sativa L.) yield under fresh and saline condition and the leaf-K/Na related database was created. Data were collected from consecutive three seasons of a field experiment in the Africa Rice Center experimental farm in Senegal (16° 11? N, 16° 15?W). We studied the relationship between the relative yield (Y_r), a ratio of yield under the salinity stress to the potential yield and the leaf-K/Na (x). Furthermore, we did regression analyses and F-test to determine the best fitting function. Results indicate that the exponential function [i.e. Y_r = 100 exp (-b x)] was the best fitting model with the lowest root mean square error (9.683) and the highest R² value (0.90). Example applications on independent data from published papers showed relatively good predictions, suggesting that the model can be used to predict rice yield in saline soils.