Frontiers of Agriculture in China

ISSN 1673-7334

ISSN 1673-744X(Online)

CN 11-5729/S

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Inheritance and molecular markers for the seed coat color in Brassica juncea
Mingli YAN, Zhongsong LIU, Chunyun GUAN, Sheyuan CHEN, Mouzhi YUAN, Xianjun LIU
Front Agric Chin. 2009, 3 (1): 1-6.

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To elucidate the inheritance of seed coat color in Brassica juncea, Sichuan Yellow inbred (PY) was crossed with the Ziyejie inbred, and their F1, F2 and BC1 and BC2 progenies, derived from backcrossing to PY, were phenotyped for seed coat color. Results showed that the yellow seed coat was controlled by two independent recessive loci. Seven brown-seeded near-isogenic lines were developed by successive backcrosses to PY and by selfing. One of the BC6F2 populations segregated for a single locus controlling seed coat color was used for mapping. Using the 88 primer pairs from sequence-related amplified polymorphism and the 500 random primers, two markers were found to be linked to the gene for brown seed coat, which were designated as SCM57 and SCM1078. The crossover between these markers and the brown seed coat loci was 2.35% and 7.06%, respectively. A sequence characterized amplified region (SCAR) marker according to Negi et al. (2000), designated as SZ1-331, was found to be linked to the gene for brown seed coat, with a cross-over estimate of 2.35%. The markers were located on the same side of the brown seed coat loci and 2.41, 7.51 and 2.41 cM away from the brown seed coat locus. The seven brown-seeded near-isogenic lines were classified into two groups by three DNA markers. They were located at the same linkage group of the marker RA2-A11 previously published by Padmaja et al. (2005).

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Influence of maize straw amendment on soil-borne diseases of winter wheat
Wenchao ZHEN, Shutong WANG, Chengyin ZHANG, Zhiying MA
Front Agric Chin. 2009, 3 (1): 7-12.

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A field experiment was conducted during the 2006—2007 wheat growing season at Baoding, Hebei Province, China, aiming at exploring the influence of different amendment rates of maize straw on winter wheat soil-borne diseases induced by Rhizoctonia cereali, Gaeumannomyces graminis and Bipolaris sorokiniana in field conditions. Wheat root vitality, ion infiltration, SOD activity, MDA content and microbial population of the tillage layer were measured. The results showed that the occurrence of three soil-borne diseases tested was significantly different under different amendment rates. During the greening stage and jointing stage, the disease indexes of three soil-borne diseases were reduced significantly by treatments at the maize straw amendment rates of 7500 kg?hm–2 and 3750 kg?hm–2. However, disease indexes of wheat common rot and sharp eyespot increased dramatically when the amendment rate increased to 15000 kg?hm–2. At the amendment rate of 15000 kg?hm–2, wheat root vigor and SOD activity decreased, and ion infiltration and cell membrane-lipid peroxidation level increased, respectively. In the meantime, higher amounts of bacteria and actinomycetes were recorded in the 7500 kg?hm–2 amendment rate treatment, while a higher amount of fungi was recorded in the 15000 kg?hm–2 amendment rate treatment.

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Correlation between specific fine root length and mycorrhizal colonization of maize in different soil types
Wenke LIU
Front Agric Chin. 2009, 3 (1): 13-15.

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A pot experiment was conducted in a glasshouse to investigate the correlation between specific fine root length (SFRL) and root colonization (RC) of maize inoculated with six arbuscular mycorrhizal fungi (AMF) in three soil types. The results showed that six AMF associated with maize presented different abilities in RC and effects on SFRL. In addition, there was a significant correlation between SFRL and RC of arbuscular mycorrhizal maize in Beijing soil (Cinnamon soil), but no significant correlation in Hubei soil (Brunisolic soil) and Guangdong soil (Red soil). It is concluded that mycorrhizal colonization decreased the SFRL of maize, and the correlation between SFRL and RC of mycorrhizal maize depended on soil type.

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Isolation and identification of the antagonistic strain DM-54 of Bacillus amyloliquefacien against Verticillium dahliae, and optimization of antifungal protein producing conditions
Ying ZHU, Shuna LI, Hongshui YUAN, Xiaojun GUO, Baocheng ZHU
Front Agric Chin. 2009, 3 (1): 16-23.

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The strains capable of resistance against Verticillium dahliae Kleb were isolated and screened from the soils of cotton fields from several different provinces in China. A strain, coded DM-54, with a rather high antagonistic activity was obtained. Its morphological characteristics, physiological and biochemical properties and a 16 S rDNA sequence of this strain were further studied. The DM-54 strain was finally identified as a kind of Bacillusamyloliquefacien. Through a single factor experiment and an orthogonal experiment, the optimal shaking flask fermentation condition of strain DM-54 was found to be: media composed of 5% dextrin, 3% soy peptone, 0.02% MgSO4, 0.01% CaCl2, initial pH 7.0 and 10% inoculum volume, media volume 30/250 (mL/mL), fermentation temperature at 32oC, rotating speed 200 r?min-1, fermentation time of 48 h. Its antagonistic activity was distinguished to be elevated, at about 39.9%. Our research offers an effective means for the massive production of antagonistic proteins.

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Cytological observation of the microspore development of Chinese kale and false pakchoi
Zhijun LI, Yanrong ZHANG, Chunyan LI, Weiping LONG, Wengjia LU, Fuguang HAN
Front Agric Chin. 2009, 3 (1): 24-28.

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The development process and morphology of the microspores in Chinese kale and false pakchoi were observed by using the whole stain-clearing technique. The results showed that the morphological characteristics of microspores were not only extremely similar, but were also in their development processes. The microspores at tetrad stage showed an arrangement of tetrahedral type, and after being released and passing through two mitoses, they developed gradually to form rotundly-shaped mature pollen grains containing three nuclei, one bigger alimentation nucleus and two smaller similar-sized generative nuclei. Determination of bud sizes at four typical microspore developmental stages revealed that the bud size had a stable heredity at each development stage of the microspores. The ratio of the bud length at the late uninucleate stage to the largest bud length differed little between Chinese kale and false pakchoi, ranging from 0.37 to 0.45 with an average of 0.41, though there was significant difference among their cultivars. It was concluded that the length of buds at late uninucleate stage can be estimated for undetermined cultivars of these two Brassica crops by multiplying the largest bud length with the following coefficient or regression equation: Y = 0.3898X+0.1503, where X is the length of the largest bud.

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Research on the development of weed-suppressing rice varieties
Shaochuan ZHOU, Decheng LU, Hong LI, Daoqiang HUANG, Ruowei MIAO
Front Agric Chin. 2009, 3 (1): 29-33.

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This study was conducted to develop weed-suppressing rice varieties in a weed-suppressing nursery by specific secondary metabolite markers of allelopathic potential. Weed-suppressing rice variety Feng-Hua-Zhan was screened out by a specific secondary metabolite marker of allelopathic potential. Weed-suppressing rice No.1, a new rice line with good quality, was also developed using this method. The genetic backgrounds and research directions of weed-suppressing rice varieties are discussed in this paper.

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Coordinated effects of root autotoxic substances and Fusarium oxysporum Schl. f. sp. fragariae on the growth and replant disease of strawberry
Xusheng ZHAO, Wenchao ZHEN, Yongzhi QI, Xuejing LIU, Baozhong YIN
Front Agric Chin. 2009, 3 (1): 34-39.

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Effects of hydroxybenzoic acid, an important autotoxic substance in roots, on plant growth, photosynthesis and Fusarium oxysporum occurrence in succession cropping of strawberry were evaluated in this paper. It was found that plant growth was negatively regulated by hydroxybenzoic acid or inoculation with F. oxysporum. Compared with these single factor treatments, the combination of the hydroxybenzoic acid treatment and F. oxysporum inoculation caused more severe inhibition in plant growth, greatly enhanced the occurrence of disease symptoms, and significantly decreased the chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration. In the meantime, the chlorophyll fluorescence parameters in strawberry were also significantly affected. After the application of hydroxybenzoic acid, the original chlorophyll fluorescence rapidly increased, resulting in a combined corresponding decrease in the maximum chlorophyll fluorescence and the chlorophyll fluorescence transformation efficiency. The effects of hydroxybenzoic acid treatment on the above chlorophyll fluorescence parameters from inoculation were delayed. Similarly, the coordination of hydroxybenzoic acid and F. oxysporum showed an elevated negative effect on the degree of inhibition of leaf photosynthesis more than the single factor treatments.

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GC-MS analysis of the chemical constituents of the essential oil from the leaves of yacon (Smallanthus sonchifolia)
Jingwei LI, Jian LIU, Hai LAN, Mingmin ZHENG, Tingzhao RONG
Front Agric Chin. 2009, 3 (1): 40-42.

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The essential oil from the leaves of yacon grown in China was isolated by hydrodistillation and distillation-extraction. Chemical constituents of the essential oil were separated and identified by means of gas chromatography/mass spectrometry (GC/MS) for the first time, and the relative content of each constituent was determined by area normalization. Twenty-one chemical constituents were identified, and their amounts accounted for 96.2% of the total composition. The main components of the essential oil were β-phellandrene (26.3%), β-cubebene (17.7%), β-caryophyllene (14.0%) and β-bourbonene (10.2%). Therefore, in the volatile oil from the leaves of yacon, sesquiterpenes are major compounds, accounting for 52.2%.

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Improvement of megaprimer method for site-directed mutagenesis and its application to phytase
Haiqiang LU, Hongwei YU, Runfang GUO, Yingmin JIA
Front Agric Chin. 2009, 3 (1): 43-46.

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Site-directed mutagenesis is used extensively for probing gene function. In this paper we describe an improved megaprimer method to the site-directed mutagenesis of phytase from Aspergillus niger, which allowed the mutations to be performed more efficiently in less time than other traditional methods. Three rounds of PCR and two pairs of primers were required in this method, and additionally, the restriction enzyme Dpn I was used for the elimination of template instead of the gel purification in this process. The entire procedure was performed in one tube. Moreover, this method was easier for obtaining large mutant genes than other methods. We successfully carried out the site-directed mutagenesis of phytase by adopting this method.

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Transcriptional responses and regulations to deficient phosphorus in plants
Jinxiang BAO, Shuhua ZHANG, Wenjing LU, Chengjin GUO, Juntao GU, Kai XIAO
Front Agric Chin. 2009, 3 (1): 47-54.

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Significant progress has been made over the past several years in the understanding of phosphorus (Pi)-starvation responses in plants and their regulation. The transcriptional changes that occur in response to Pi starvation are beginning to be revealed, although much is left to understand about their significance. In this paper, the recent progresses on the gene expression changes under deficient-Pi, cis-regulatory elements involved in response to deficient-Pi, the transcriptional control of Pi-starvation responses in eukaryotes, transcription factors involved in response to Pi-starvation, the role of MicroRNA on regulation of phosphate homeostasis, and phosphate sensing and signal transduction in plants have been summarized. The purpose of this review is to provide some basis for further elucidation of the transcriptional responses and regulations, and the networks of Pi sensing and signal transduction under deficient-Pi in plants in the future.

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Cloning of strawberry FaEtr2 gene and its plant expression vector construction for antisense RNA
Chunli SONG, Pingping ZHOU, Junlian MA, Xia TANG, Zide ZHANG, Zhixia HOU
Front Agric Chin. 2009, 3 (1): 55-59.

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An ethylene receptor FaEtr2 gene was amplified by Polymerase Chain Reaction (PCR) from ripening strawberry fruit. A 1049-bp PCR product (All Star-Etr2) was cloned. Sequence analysis showed that the All Star-Etr2 nucleotide sequence had 100% identity with Chandler-Etr2 from the GenBank. A pair of primers containing restriction enzyme sites were designed and used to amplify the sequenced plasmid. The PCR product was digested by the corresponding restricted enzymes and inserted between the CaMV 35S promoter and NOS terminator of expression vector pBI121 directionally. The constructed expression vector was transformed into Agrobacterium fumefeciens LBA4404 in the follow-up research to silence a ripening-related ethylene receptor FaEtr2 gene in strawberry fruits.

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Adventitious shoot regeneration from the leaves of in vitro grown ‘Zhongli 1’ pear (Pyrus spp.)
Jie LIU, Yuxing ZHANG, Jing QI, Xi ZHANG, Bharat Kumar POUDYAL, Zhan JIAO
Front Agric Chin. 2009, 3 (1): 60-66.

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The pear (Pyrus spp.) is one of the most important temperate fruit crops. The technique of adventitious shoot regeneration from leaves is considered to be one of the shortcuts in the research on pear genetic modification and cellular engineering, which, however, has not been widely used. As the regeneration frequency of pear leaves is usually very low, the research on adventitious shoot regeneration from pear leaves is eagerly needed. In this experiment, the factors affecting shoot and bud regeneration from the leaves of ‘Zhongli 1’ pear were studied, and an efficient protocol for shoot regeneration was established. The results showed that different types of basic media, different combinations of plant growth regulators, leaf placement on medium, periods of dark culture and the use of silver nitrate (AgNO3) on culture media all significantly affected the adventitious shoot regeneration frequency of ‘Zhongli 1’ pear. The details are as follows: (1) Among three kinds of basic media, NN69 was better for ‘Zhongli 1’ shoot regeneration, followed by half (?) MS, while full MS had no effect on shoot regeneration; (2) Thidiazuron (TDZ) was better than 6-benzylaminopurine (6-BA) for ‘Zhongli 1’ regeneration, with an optimal concentration of 1.5 mg·L-1, and the regeneration rate under this concentration could reach 85%, with 2.72 buds per leaf. 0.5 mg·L-1 indole-3-butyric acid (IBA), which induced a higher regeneration frequency, was a better choice for pear regeneration compared with 0.3 mg·L-1 naphthaleneacetic acid (NAA). Among the different combinations of plant growth regulators, TDZ + IBA was better for inducing high regeneration frequency; (3) The abaxial surface of leaves touching the medium was beneficial for leaves to uptake nutrients from the medium, and because of that, the regeneration frequency of leaves was significantly higher than that of leaves touching the medium with their adaxial surfaces (obverse side of leaf); (4) Dark culture was necessary for bud regeneration, and the best duration for dark culture of ‘Zhongli 1’ pear was 21 days; (5) The addition of 1.0 mg·L-1 AgNO3 into the culture medium could promote adventitious shoot regeneration significantly. A high adventitious shoot regeneration frequency was obtained in this research, which will be beneficial for further research on efficient and stable in vitro plant regeneration systems and genetic modification of pear.

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Construction of a genetic linkage map and QTL analysis for some leaf traits in pear (Pyrus L.)
Wenying SUN, Yuxing ZHANG, Wenying SUN, Wenquan LE, Hai’e ZHANG
Front Agric Chin. 2009, 3 (1): 67-74.

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The major incompatibility barriers to specific inbred lines and the long generation duration in Pyrus L. may hinder the Pyrus breeding process. A genetic linkage map provides the foundation for quantitative trait loci (QTL) mapping and molecular marker-assisted breeding. In this study, we constructed a genetic map with 145 F1 populations from a cross of two cultivars, Yali and Jingbaili, using AFLP and SSR markers. The map consisted of 18 linkage groups which included 402 genetic markers and covered 1395.9 cM, with an average genetic distance of 3.8 cM. The interval mapping was used to identify quantitative trait loci associated with four leaf agronomic traits in the F1 population. The results indicated that four QTLs were associated with leaf length, two QTLs with leaf width, two with leaf length/leaf width, and three with petiole length. The eleven QTLs were associated with 9.9%-48.5% of the phenotypic variation in different traits. It is considered that the map covers almost the whole genome, and molecular markers will be greatly helpful to the related breeding.

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Research Article
The main factors causing “imperfect shell development” (ISD) in thin-shelled walnut
Baoguo LI, Suping GUO, Guohui QI
Front Agric Chin. 2009, 3 (1): 75-77.

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Effects of solar radiation, rainfall and cultivars on “imperfect shell development” (ISD) of the thin-shelled walnut were studied by means of field investigation and weather data comparison. The results showed that cultivars were the main factor causing the ISD of the thin-shelled walnut. Among the cultivars, Shangsong 6 was the most sensitive one, whose percentage of imperfect shell attained 67.3%, followed by Xiangling (52.7%). However, the rate of imperfect shells in Zhonglin 5 was only 20.9%. It was suggested that the main environmental factors contributing to the ISD of the thin-shelled walnut were sunlight intensity and rainfall during the shell-hardening stage.

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Effects of dietary squid viscera meal on growth and cadmium accumulation in tissues of large yellow croaker, Pseudosciaena crocea R.
Huitao LI, Kangsen MAI, Qinghui AI, Chunxiao ZHANG, Lu ZHANG
Front Agric Chin. 2009, 3 (1): 78-83.

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Cadmium (Cd) is a toxic environmental pollutant with a long biological half-life and can produce both hepatic and renal injuries in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on the growth and Cd deposition in the tissues of large yellow croaker, Pseudosciaena crocea R. Three practical diets were formulated to contain a 0, 50 and 100 g?kg-1 SVM diet, correspondingly containing a 0.21, 7.26 and 12.08 mg Cd·kg-1 diet. Each diet was randomly assigned to triplicate groups of 100 juveniles of large yellow croaker (mean initial weight, 9.75±0.35 g) in floating sea cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (05:00 and 17:00) to satiation for 8 weeks. The results showed that there were no significant differences in fish survival among the three dietary treatments, but significant higher specific growth rates (SGR) were observed in the fish fed diets with 50 or 100 g?kg-1 SVMdiet compared to the control group (P<0.05). The cadmium concentrations in fish tissues (muscle, liver, kidney and gill) were significantly influenced by the dietary SVM. The cadmium concentrations in all tissues significantly increased with increasing dietary Cd levels (P<0.05). In all the dietary treatments, the highest Cd level was always observed in the kidney, followed by the liver and the gill. Fish fed diets with 50 and 100 g?kg-1 SVM had significantly higher Cd accumulations in the kidney (2.65, 4.44 mg?kg-1), liver (0.58, 0.93 mg?kg-1) and gill (0.35, 0.53 mg?kg-1) compared with the control group (0.42, 0.26 and 0.12 mg?kg-1, respectively). The Cd level in fish muscle, however, was undetectable in all treatments. Therefore, based on these results, accumulation of Cd in edible tissue (muscle) of farmed large yellow croaker is not a food safety issue. However, long-term feeding of diets with SVM may result in accumulation of Cd in the kidney, liver and gills of fish.

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Effects of microbial agents on small intestinal structure and the quantity of cecal microorganisms in broilers
Yaodi NI, Xiuhui ZHONG, Haifeng WANG, Li XU, Shupeng WEI
Front Agric Chin. 2009, 3 (1): 84-88.

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In order to elucidate the significance and related mechanisms of microbial agents in modulating the growth of broilers, one-day-old Avian broilers were employed to investigate the effect of microbial agents on body weight, daily gain and feed efficiency at various stages. The birds in the experimental groups were given salmonella pullorum then fed with antibiotics to counteract it. The results showed that the average broiler weight of the oral microbial agent group at the age of 40 days was significantly increased by 16.58% from 1520 g to 1772 g (P<0.05). The feed conversion efficiency was decreased from 2.21 to 1.82 (P<0.01). In the experimental group fed with microbial agents, microscopic observation revealed that the intestinal villi increased in number, length and orderliness. The intestinal wall became thickened. The glands in the intestine were developed, which would be beneficial to nutrient absorption. The effect of oral microbial agents was identical to that due to antibiotics. It was also observed that Lactobacillusdominated the cecal microorganisms in broilers.

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Research on Y. schidigera extract feeding on the rumen ecology, protozoal populations and serum chemistries of sheep
Chunlong LIU, Zhongqiu LI, Fugang PENG, Yanming REN, Zhuolong WANG
Front Agric Chin. 2009, 3 (1): 89-94.

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In a completely randomized block design experiment, 16 ruminally cannulated male sheep with body weights of (40 ± 2.1) kg were fed twice daily (8:00 and 16:00) with concentrate and forage (50:50 on dry matter (DM) basis). Dietary treatments were supplemented with intraruminal doses of powdered Yucca schidigera extract (YSE) at the levels of 0 (control), 100, 200 and 300 mg?kg-1. On days of 15, 16 and 17 after feeding, ruminal content was sampled at 0, 2, 4, 6 and 8 h after dosing (8:00), and blood samples were collected at the end of experiment (the days 18 and 19 after feeding). Results showed that the treatment groups’ acidity was not affected (P = 0.13) by YSE. Comparing to the control, the ruminal propionate concentration was increased by YSE addition in a dose-dependent manner by up to 29.8% (P< 0.05), and the acetic concentration was decreased by up to 17.5% (P< 0.05). The ruminal ammonia concentration 2 hours after feeding was higher (P< 0.05) in sheep fed without YSE (increased by 17.57 mg?100 mL-1) than those fed with YSE at 200 mg?kg-1 (6.77 mg?100 mL-1increase in NH3) and at 300 mg?kg-1 (6.50 mg?100 mL-1 increase in NH3). Protozoal populations in the rumen were lower (P< 0.05) with the YSE feeding dose at 300 mg?kg-1 than the control. The serum chemistries were not different among treatments (P > 0.05) and were within the normal physiological ranges for sheep 19 days after feeding. The study indicated that 200 mg?kg-1 and 300 mg?kg-1 YSE groups had particular suppressing effects on ruminal ammonia concentration, ammonia-N concentrations and protozoal populations. The effect of YSE on ruminal fermentation could be attributed to the selective inhibitory effect on rumen microbial species. High level (300 mg?kg-1) YSE as feed additives resulted no negative impact on sheep in our tests.

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Protective effects of selenium and vitamin E on rats consuming maize naturally contaminated with mycotoxins
Jie YU, Daiwen CHEN, Bing YU
Front Agric Chin. 2009, 3 (1): 95-99.

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Protective effects of antioxidant additives of selenium and vitamin E on rats that consumed maize naturally contaminated with mycotoxins were explored in this paper. Thirty-two Wistar female rats were randomly divided into four groups. The control group was given the basic diet with normal maize. The contaminated maize group was given the diet in which normal maize was replaced by mycotoxin-contaminated maize. The selenium group and vitamin E group were respectively fed mycotoxin-contaminated diet supplemented with 0.4 mg?middot;kg-1 selenium from yeast or 100 mg?middot;kg-1 vitamin E. The trial lasted for 4 weeks. Compared with the control group, antioxidative status was decreased significantly in the contaminated maize group. However, the status in the selenium group and vitamin E group was increased significantly compared with the contaminated maize group. The activities of enzymes related with liver function were significantly higher in the contaminated maize group than those in the control group, whereas they were significantly lower in the selenium group and/or the vitamin E group compared to the contaminated maize group. It is concluded that selenium and vitamin E were able to alleviate oxidative stress and liver function damage due to the consumption of maize naturally contaminated with mycotoxins.

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Detection of Eperythrozoon wenyoni by PCR assay
Jian WANG, Yutao ZHU, Jianhua QIN, Jian WANG, Fumei ZHANG, Yuelan ZHAO
Front Agric Chin. 2009, 3 (1): 100-103.

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The objective of this research was to develop a detection method for Eperythrozoon wenyoni infection using polymerase chain reaction (PCR) assay technique. A pair of primers was designed and synthesized according to the conservative sequence 16S rRNA. The PCR assay was performed with the primers. A 985-bp fragment was amplified by using PCR. The amplified fragments with the expected size were identified by EcoR I restriction digestion. The crossing-reaction, specific-reaction and duplicate-reaction indicated that the PCR method is a specific, sensitive, fast and effective method for diagnosing E. wenyoni infection at group level.

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Research Article
Prophylactic and therapeutic effects of egg yolk immunoglobulin against porcine transmissible gastroenteritis virus in piglets
Yuzhu ZUO, Jinghui FAN, Huixia FAN, Tanqing LI, Xiaobo ZHANG
Front Agric Chin. 2009, 3 (1): 104-108.

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Porcine transmissible gastroenteritis virus (TGEV) is the causative agent of acute diarrhea of newborn piglets that provokes high mortality rates in affected farms. In this study, specific immunoglobulin from egg yolk against TGEV was produced by immunization of White leghorn hens. Enzyme-linked immunosorbent assay (ELISA) and virus neutralization (VN) test revealed that the specific antibody titer started to increase on the tenth day post-immunization, reached its peak on the eighth week, and remained at a high level until the last week that we tested. The prophylactic and therapeutic effects of egg yolk immunoglobulin (IgY) was investigated in piglets. IgY was found effective to increase piglets survival rate significantly after challenge exposures in prophylactic efficacy analysis. The therapeutic effects test revealed that the mortality was dramatically reduced by orally administered IgY. All these results in our study indicated that IgY specific to TGEV could be an alternative prophylactic method like colostral antibodies against TGEV in piglets.

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