Agricultural Sciences in China最新文献

{"title":"Insecticidal Constructure and Bioactivities of Compounds from Ficus sarmentosa var. henryi","authors":"Xue-gui WANG ,&nbsp;Xiao-yi WEI ,&nbsp;Xing-yan HUANG ,&nbsp;Li-tao SHEN ,&nbsp;Yong-qing TIAN ,&nbsp;Han-hong XU","doi":"10.1016/S1671-2927(11)60133-8","DOIUrl":"10.1016/S1671-2927(11)60133-8","url":null,"abstract":"<div><p>Insecticidal activities of the petroleum ether-, chloroform-, ethyl acetate-, and water-soluble fractions of the methanolic extract of <em>Ficus sarmentosa</em> var. <em>henryi</em> were assayed against <em>Musca domestica</em> adults. The chloroform- and ethyl acetate-soluble fractions were the most active with 92.6 and 88.9% mortalities (24 h after treatment) respectively. Therefore, the two fractions were combined and four compounds, isolated from the fractions by activity-guided fractionation, were elucidated as 7-hydroxycoumarin, apigenin, eriodictyol, and quercetin by spectroscopic method and displayed excellent insecticidal activities against adults <em>of M. domestica</em> and 4th instar larva of <em>Aedes albopictus.</em> Among those, 7-hydroxycoumarin showed the strongest insecticidal activities with lethal concentrations (LC₅₀) values of 72.13 μg g⁻¹ sugar and 4.87 μg mL⁻¹ (48 h after treatment) against the test insects respectively. The cytoxicities of these compounds on BTI-Tn-5Bl-4 cell were also investigated for the insecticidal mechanism and found that quercetin represented superior inhibitory activity with MTT assay and reactive oxygen species (ROS) against BTI-Tn-5Bl-4 cell, but slightly weaker than that of the positive control (azadirachtin) and significantly greater than the negative control (DMSO only). Meanwhile, eriodictyol demonstrated the strongest effect on the mitochondrial membrane potentials (MMP). In conclusion, based on their comparative toxicities to commercial insecticides and their cytotoxic effects, some of the compounds from the <em>F. sarmentosa</em> have potential as botanical insecticides.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 9","pages":"Pages 1402-1409"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60133-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56762055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Host Plants on Development, Fecundity and Enzyme Activity of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)","authors":"Bin ZHANG Ph D ,&nbsp;Huai LIU ,&nbsp;Hull-Sanders Helen ,&nbsp;Jin-jun WANG","doi":"10.1016/S1671-2927(11)60114-4","DOIUrl":"10.1016/S1671-2927(11)60114-4","url":null,"abstract":"<div><p>The beet armyworm, <em>Spodoptera exigua</em> (Lepidoptera: Noctuidae), is an economically important pest of crops worldwide, attacking plants from over 20 families including <em>trans</em>-continental agricultural cotton, corn and citrus crops. In this study, performance and subsequent enzyme activity of beet armyworm reared on host plants from five families were investigated. Significant differences were found in development, fecundity and enzyme activity on different host plants. Survival rate was the highest (42.8%) on asparagus lettuce <em>(Lactuca sativar</em> var. <em>asparagina)</em> and the lowest (17.0%) on sweet pepper <em>(Capsicum annuum).</em> Larval duration was the shortest on asparagus lettuce (12.0 d), and was 43.4% longer on sweet peppers (21.2 d). The activity of acetylcholine esterase (AChE) and carboxylesterase (CarE) in 3rd instar larvae, and soluble carbohydrate and crude protein contents in different host plants were determined. AChE activity was the highest in the larvae feeding on Chinese cabbage <em>(Brassica rapa),</em> but declined by nearly 60% on maize <em>(Zea mays)</em> seedlings. The ratio of soluble carbohydrate content to crude protein content in host plants was found to have a positive effect on oviposition and a negative correlation with larval duration and life time (from larval to adult stages) of the insect.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1232-1240"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60114-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56756856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utilization of Chinese Herbal Feed Additives in Animal Production","authors":"Hua-wei LIU ,&nbsp;Jian-ming TONG ,&nbsp;Dao-wei ZHOU","doi":"10.1016/S1671-2927(11)60118-1","DOIUrl":"10.1016/S1671-2927(11)60118-1","url":null,"abstract":"<div><p>The experimental knowledge on efficacy, possible modes of action and aspects of application of Chinese herbs as feed additives for animal production are reviewed in this article. Chinese herbs commonly contain protein, carbohydrate, fat, vitamins, and mineral which are necessary nutrients to the growth of animal. Polysaccharide, organic acid, alkaloids, and essential oils involved in Chinese herbs can improve the immune function of livestock. Currently, numerous studies have demonstrated anti-oxidative and anti-microbial efficacy and the assumption that Chinese herbs may improve the flavor of meat, which has been confirmed by some observations, but the mode of this action is still unclear. Moreover, several observations support the hypothesis that herbal feed additives may favorably affect gut functions (e.g., enzyme activity, microbial eubiosis) <em>in vitro.</em> Such effects may explain a considerable number of practical studies with livestock reporting improved production performance after providing herbal feed additives. In summary, available evidence indicates that herbal feed additives may have the potential to add to the set of non-antibiotic growth promoters for use in livestock, such as organic acids and probiotics. However, a systematic approach toward the efficacy, mode of action and safety of herbal compounds used as feed additives for animal production seems to be required in the future.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1262-1272"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60118-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56760161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of Organic Substances Associated with Tissue Senescence in Upland Cotton (Gossypium spp. L.) Based on GC-MS Analysis","authors":"Zhen-long XU ,&nbsp;Cheng-jin GUO ,&nbsp;Jun-tao GU ,&nbsp;Wen-jing LU ,&nbsp;Xiao-juan LI ,&nbsp;Kai XIAO","doi":"10.1016/S1671-2927(11)60110-7","DOIUrl":"10.1016/S1671-2927(11)60110-7","url":null,"abstract":"<div><p>Premature senescence in crop production, especially occurred at the late growth stage, generally results in a reduction in yield and quality. Therefore, it is beneficial for yield and quality to properly delay senescence of plant tissues during the late developmental stage. In this study, it was observed that the chlorophyll content and photosynthetic rate were gradually decreased along leaf growth progression, and the rates of reduction were promoted by drought. Based on gas chromatography-mass spectrometry (GC-MS) analysis, total eight, five, seven, and five kinds of organic compounds that putatively associated with the tissue senescent progression were identified in leaves, fruit branches, petals, and sepals, respectively. It was found that the identified organic compound, such as a-pinene, β-pinene, and pentadecane were present in different tissues. Among the total ten organic substances identified to be related with the leaf senescence, half were specifically detected in the drought treatment. These results suggest some biochemical pathways associated with the leaf senescence are distinctly regulated by drought. The identified organic compounds in the tested tissues showed three types on the performance pattern based on the contents along with the senescent progression, including gradually increasing, decreasing, and a curve with one single peak. Thus, during the senescence process in tissues, a subset of metabolic substances occur modifications on the quantities, reflecting a complicate biochemical reactions are initiated via the senescence signals. Further analysis of the important organic substances will be helpful for elucidation of the tissue senescence mechanism at the biochemical level and provide a new insight of the senescence signaling transductions in cotton.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1197-1205"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60110-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56753110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Improvement of Resistance to Late Blight in Tetraploid Potato: A Case Study in Combination with AFLP Marker Assisted Background Selection","authors":"Chun-guang YAO ,&nbsp;Bo-tao SONG ,&nbsp;Jun LIU ,&nbsp;Cheng-jin WU ,&nbsp;Qun CHENG ,&nbsp;Da-chun LI ,&nbsp;Cong-hua XIE","doi":"10.1016/S1671-2927(11)60108-9","DOIUrl":"10.1016/S1671-2927(11)60108-9","url":null,"abstract":"<div><p>Cultivated potato with high level of horizontal resistance against late blight is one of the most important goals of potato breeding. The recurrent selection has been adopted to increase the level of potato horizontal resistance and a B3C1 population without <em>R1 -R11</em> dominant genes has been released by the International Potato Center at the short-day condition of Peru. The present research was carried out to further improve the resistance and the agronomic traits of B3C1 population under long-day condition of Hubei, China, with maximized retention of its genetic diversity. Twenty-seven individual clones of B3C1 were used to generate population B3C2 by in-population crossing with the bulk pollens aiming to elevate the frequency of late blight resistance genotypes and to improve the adaptation to local long-day conditions. The late blight resistance and the main agronomic traits including the maturity, the plant characters and the tuber traits were evaluated for the foreground selection in three years, by which 130 pedigrees were maintained as the basic population of B3C2 for further selection. A total of 312 polymorphic loci detected by 9 AFLP marker combinations were used to monitor the genetic diversity of the populations for the background selection. The B3C2 population of 51 clones was finally selected, of which the frequency of resistant genotypes increased by 23.8% points and the genetic diversity was maintained by about 96% as referred to B3C1. Our results strongly suggested that combination of the foreground selection for target traits and the background selection for the genetic diversity is an efficient strategy in the recurrent selection of tetraploid potato to improve quantitative traits.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1177-1187"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60108-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56750920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cokriging of Soil Cation Exchange Capacity Using the First Principal Component Derived from Soil Physico-Chemical Properties","authors":"Kai-hua LIAO ,&nbsp;Shao-hui XU ,&nbsp;Ji-chun WU ,&nbsp;Shu-hua JI ,&nbsp;Qing LIN","doi":"10.1016/S1671-2927(11)60116-8","DOIUrl":"10.1016/S1671-2927(11)60116-8","url":null,"abstract":"<div><p>As soil cation exchange capacity (CEC) is a vital indicator of soil quality and pollutant sequestration capacity, a study was conducted to evaluate cokriging of CEC with the principal components derived from soil physico-chemical properties. In Qingdao, China, 107 soil samples were collected. Soil CEC was estimated by using 86 soil samples for prediction and 21 soil samples for test. The first two principal components (PC1 and PC2) together explained 60.2% of the total variance of soil physico-chemical properties. The PC1 was highly correlated with CEC <em>(r</em>=0.76, <em>P</em>&lt;0.01), whereas there was no significant correlation between CEC and PC2 (<em>r</em>=0.03). The PC1 was then used as an auxiliary variable for the prediction of soil CEC. Mean error (ME) and root mean square error (RMSE) of kriging for the test dataset were −1.76 and 3.67 cmol_c kg⁻¹, and ME and RMSE of cokriging for the test dataset were −1.47 and 2.95 cmol_c kg⁻¹, respectively. The cross-validation <em>R</em>² for the prediction dataset was 0.24 for kriging and 0.39 for cokriging. The results show that cokriging with PC1 is more reliable than kriging for spatial interpolation. In addition, principal components have the highest potential for cokriging predictions when the principal components have good correlations with the primary variables.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1246-1253"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60116-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56758024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmacokinetics of Quinocetone and Its Major Metabolites in Swine After Intravenous and Oral Administration","authors":"Jia-lin ZHONG,&nbsp;Gui-jun ZHANG,&nbsp;Xiang-guang SHEN,&nbsp;Lin WANG,&nbsp;Bing-hu FANG,&nbsp;Huan-zhong DING","doi":"10.1016/S1671-2927(11)60121-1","DOIUrl":"10.1016/S1671-2927(11)60121-1","url":null,"abstract":"<div><p>The pharmacokinetics of quinocetone and its major metabolites in healthy swine was investigated in this paper. Quinocetone was administered to 8 healthy cross-bread swine intravenously and orally at a dosage of 4 and 40 mg kg⁻¹ body weight respectively in a randomized crossover design test with two-week washout period. A sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of quinocetone and its metabolite 1-desoxyquinocetone in plasma. Plasma concentration versus time profiles of quinocetone and its metabolite 1-desoxy quinocetone were analyzed by non-compartmental analysis using Winnonlin 5.2 software. Mean maximum concentrations (C_max) for quinocetone was found to be (0.56±0.13) μg mL⁻¹ at 2.92 h, after oral administration of quinocetone. Mean maximum concentrations (C_max) for 1-desoxy quinocetone after intravenous or oral administration of quinocetone were (0.0095±0.0012) μg mL·¹ at 0.083 h and (0.0067±0.0053) μg mL⁻¹ at 3.08 h. The apparent elimination half-lives (T_1/2) for quinocetone and its metabolite 1-desoxy quinocetone were (2.24±0.24) and (5.23±0.56) h after intravenous administration of quinocetone and (2.91±0.29) and (11.85±2.89) h after oral administration of quinocetone, respectively. Mean areas under the plasma concentration-time curve (AUC_0-x) for quinocetone and 1-desoxyquinocetone were (2.02±0.15) and (0.2±0.002) μg h mL⁻¹ respectively after intravenous administration of quinocetone, and (3.5±0.79) and (0.053±0.03) μg h mL⁻¹ after oral administration of quinocetone, respectively. Quinocetone was rapidly absorbed and metabolized in swine after oral and intravenous administration. The plasma concentration-time curve (AUC_0-x) of 1-desoxy quinocetone were much smaller than those of quinocetone, while the elimination half-lives (T_1/2) were much longer than those of quinocetone after intravenously (i.v.) or oral administration.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1292-1300"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60121-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56761811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation and Characterization of NBS-LRR Class Resistance Homologous Gene from Wheat","authors":"Nan ZHANG,&nbsp;Shen WANG,&nbsp;Hai-yan WANG,&nbsp;Da-qun LIU","doi":"10.1016/S1671-2927(11)60105-3","DOIUrl":"10.1016/S1671-2927(11)60105-3","url":null,"abstract":"<div><p>One resistance gene analog fragment named <em>RGA-CIN14</em> was isolated from TcLr19 wheat, which contains kinase-2, kinase-3a, and the GLPL motif of the NBS-spanning region, using degenerated primers according to the nucleotide binding site (NBS) conserved domain. Based on the <em>RGA-CIN14,</em> a full-length cDNA, <em>CIN14,</em> which was 2 987 bp encoding 880 amino acids, was obtained by using the method of the rapid amplification cDNA ends (RACE). Bioinformatics analysis showed that the deduced amino acids of CIN14 protein consisted of a NB-ARC conserved domain and many leucine-rich repeats (LRR) domains. The phylogenetic tree analysis indicated a considerable identity of the protein encoded by <em>CIN14</em> with that of wheat leaf rust resistance gene <em>Lr1,</em> but a lower similarity with <em>Lr21.</em> The expression profile of the <em>CIN14</em> gene detected by semi-quantitative RT-PCR showed that the <em>CIN14</em> gene was not induced by <em>Puccinia triticina</em> and it was a constitutive gene with low abundance in the wheat leaf tissue. The resistance homology sequence was successfully obtained, which provides the shortcut for cloning of the resistance gene in TcLr19 wheat.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1151-1158"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60105-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56751347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proteomic Comparison Between Leaves from a Red-Flesh Mutant and Its Wild-Type in Sweet Orange","authors":"Zhi-yong PAN,&nbsp;Xiu-xin DENG","doi":"10.1016/S1671-2927(11)60111-9","DOIUrl":"10.1016/S1671-2927(11)60111-9","url":null,"abstract":"<div><p>The red-flesh mutant Hong Anliu sweet orange is of high nutritional value due to its lycopene accumulation. Our previous studies on this mutant fruits suggested that photosynthesis and oxidative stress could promote the formation of mutation trait. However, leaf rather than fruit is the major part for some important biological processes such as photosynthesis. In this study, we analyzed the proteomic alteration in leaves of the red-flesh mutant Hong Anliu <em>vs.</em> its wild type (WT). Ten differentially expressed proteins were identified, of which two were involved in photosynthesis, three in oxidative stress, two in defense, and three in metabolism. The high up-regulation of photosynthetic proteins proved the hypothesis that enhanced photosynthesis could provide and transport more substrates into mutant fruits for carotenoid biosynthesis. Similar to the previous results in fruits, anti-oxidative proteins were highly up-regulated in leaves, suggesting the whole plant of Hong Anliu suffered from enhanced oxidative stress. Proteins involved in defense and metabolism were also identified, and their possible roles in the mutation were discussed.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1206-1212"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60111-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56754238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Pathogenicity of a Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Variant in Piglets","authors":"Tian-chao WEI Ph D ,&nbsp;Zhi-jun TIAN ,&nbsp;Yan-jun ZHOU ,&nbsp;Tong-qing AN ,&nbsp;Yi-feng JIANG ,&nbsp;Yan XIAO ,&nbsp;Shouping HU ,&nbsp;Jin-mei PENG ,&nbsp;Xiao-fang HAO ,&nbsp;Shan-rui ZHANG ,&nbsp;Guang-zhi TONG","doi":"10.1016/S1671-2927(11)60120-X","DOIUrl":"10.1016/S1671-2927(11)60120-X","url":null,"abstract":"<div><p>Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China's pig industry. To investigate the <em>in vivo</em> pathogenicity and immune responses of the newly emerging PRRSV, 3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses (3(10³-3(10⁵ TCID₅₀). The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever (41.0–41.9°C) and high morbidity and mortality (60-100%), the marked clinical signs of PRRS and severe histopathogenie damages in multiple organs. It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection (DPI). The virus vigorously replicated <em>in vivo</em> and the highest virus average titer was 9.7 log copies mL⁻¹ serum at 7 DPI. Elevated levels of IFN-γ and IL-10 cytokine production in serum in this study were also observed. Taken together, our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.</p></div>","PeriodicalId":7475,"journal":{"name":"Agricultural Sciences in China","volume":"10 8","pages":"Pages 1280-1291"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1671-2927(11)60120-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56761757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}