一例猪附红细胞体与弓形体混合感染的诊治     

崔双保  和彩红 《中国兽药杂志》2006,40(3):58-59

附红细胞体病是由立克次氏体引起的一种散在的热性、溶血性入畜共患传染病，病猪以急性黄疸性贫血和发热为特征。弓形体病是由刚地弓形虫在多种动物和入的有核细胞内寄生引起的一种入畜共患的原虫病。本文通过对某猪场发生猪附红细胞体与弓形体混合感染的诊治，从发病情况、临床症状、剖检变化、实验室诊断、治疗等方面对该病进行了阐述。  相似文献   

Physiology and Biochemistry of Free-Living and Plant Parasitic Nematodes     

Opperman 《Plant pathology》2000,49(1):167-168

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Sources and inheritance of resistance to stemphylium leaf spot of lettuce     

D. Netzer  D. Globerson  CH. Weintal  R. Elyassi 《Euphytica》1985,34(2):393-396

Summary None of the tested cultivars of lettuce was found resistant to Stemphylium leaf spot, a common disease in Israel. Within a Lactuca saligna population collected in wild lettuce in Israel, resistance was traced. Interspecific crosses of L. saligna x L. sativa were made and the mode of inheritance of resistance to this disease was studied. Resistance is apparently controlled by two genes: one dominant (Sm₁) and one recessive (sm₂).Contribution No. 1176-E 1984 series, from the ARO.  相似文献   

小麦D~2型细胞质光敏雄性不育性的研究     

于天峰  刁艳玲  车京玉  迟永琴  李长辉  王岩  邵立刚  张爱民  鄂立柱 《东北农业大学学报》2002,33(4):324-330

D2型细胞质与有些普通小麦材料的细胞核互作,可产生特异核质互作不育现象,其中有的表现为长光照敏感型雄性不育。文章研究了具有D2型细胞质的光敏不育系Ae.crassa—Norin26、核质杂种NC2134及克引11、克引12在黑龙江省克山地区自然条件下的育性表现,并以NC2134为细胞质供体,与20个小麦品种(系)杂交,获得一些核质代换系材料,对其育性及主要性状进行观察研究。结果表明:(1)在自然条件下,播种期对育性有影响,随着播种期推迟,Ae.crassa—Norin26不育度增加,1 999年4月22日播种达到全不育,Norin26则在所设播种条件下表现正常可育;(2)NC2134表现可育,这与其可能携带雄性不育的恢复基因有关,克引11、克引12在正常播种情况下表现高度不育甚至全不育;(3)不育系的不育性表现为不同程度的雄蕊心皮化;(4)不同普通小麦材料其核质杂种育性表现不同,有些材料其核质代换低世代分离出一定比例的高不育、半不育及可育株,通过进一步的核置换,可转育成相应的D2型细胞质不育系。  相似文献   

Excitation Gap in the Normal State of Underdoped Bi2Sr2CaCu2O8+delta     

AG Loeser  Z Shen  DS Dessau  DS Marshall  CH Park  P Fournier  A Kapitulnik 《Science (New York, N.Y.)》1996,273(5273):325-329

Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.  相似文献   

First Report of Post‐Weaning Multisystemic Wasting Syndrome and Porcine Dermatitis and Nephropathy Syndrome in Pigs in Greece     

K. SAOULIDIS  S. C. KYRIAKIS  S. KENNEDY  S. LEKKAS  CH. C. MILIOTIS  G. ALLAN  G. C. BALKAMOS  P. A. PAPOUTSIS 《Zoonoses and public health》2002,49(4):202-205

Post‐weaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS) are two recently described conditions of pigs at the late nursery and fattening stages. The aim of this short communication was to describe the first reported occurrence of these conditions and of porcine circovirus type 2 (PCV2) infection in Greece. The clinical signs, gross post‐mortem changes and histopathological changes observed in affected pigs, were similar to those previously described for both PDNS and PMWS. As in previous reports, the lesions were associated with PCV2 infection, which was demonstrated by immunohistochemical and in situ hybridization methods.  相似文献   

Virulence Genes in Heterodera glycines: Allele Frequencies and Ror Gene Groups Among Field Isolates and Inbred Lines     

Dong K  Barker KR  Opperman CH 《Phytopathology》2005,95(2):186-191

ABSTRACT Genetic variation in field populations of Heterodera glycines is a key issue for both resistance gene deployment and basic understanding of virulence-gene flow in populations. In this study, we examined phenotypically defined genes for virulence under selection from host resistance. We separated the most common H. glycines genotypes in the United States into two virulence groups, based on their reproductive abilities on the resistant soybean plant introduction (PI) 88788. These groups correspond to previously identified virulence genes in the nematode, as follows: the dominant gene in H. glycines to PI88788, and the recessive genes to PI90763 and Pickett/Peking. Virulence allele frequencies and virulence genotype frequencies of selected field isolates were investigated by testing the host range of single-female-derived lines, which were developed through single-female inoculation on the standard susceptible soybean 'Lee 68'. By comparing virulence genotype frequencies between the original field isolates and their single-female-derived lines, we were able to determine allele frequencies in the field populations. The results suggest that tremendous variation in H. glycines virulence genes exists among field populations. Potential mechanisms of selection which could cause virulence genotype frequency increases are discussed as related to population genetics equilibrium theory.  相似文献   

Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae     

Juliana DF Barbosa  Viviane B Silva  Péricles B Alves  Giuseppe Gumina  Roseli LC Santos  Damião P Sousa  Sócrates CH Cavalcanti 《Pest management science》2012,68(11):1478-1483

BACKGROUND: Dengue fever is a severe public health problem for several countries. In order to find effective larvicides to aid control programs, the structure‐activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae were evaluated. Additionally, the composition and larvicidal activity of Syzygium aromaticum essential oil was assessed. RESULTS: Four compounds representing 99.05% of S. aromaticum essential oil have been identified. The essential oil was active against Ae. aegypti larvae (LC₅₀ = 62.3 and 77.0 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity of eugenol, the major compound of the essential oil, was further evaluated (LC₅₀ = 93.3 and 71.9 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity and structure‐activity relationships of synthetic derivatives of eugenol were also assessed. The larvicidal activity of the derivatives varied between 62.3 and 1614.9 ppm. Oxidation of eugenol allylic bond to a primary alcohol and removal of the phenolic proton resulted in decreased potency. However, oxidation of the same double bond in 1‐benzoate‐2‐methoxy‐4‐(2‐propen‐1‐yl)‐phenol resulted in increased potency. CONCLUSION: Structural characteristics were identified that may contribute to the understanding of the larvicidal activity of phenylpropanoids. The present approach may help future work in the search for larvicidal compounds. Copyright © 2012 Society of Chemical Industry  相似文献   

Veld management recommendations ‐ a reassessment of key species and proper use factors     

B.R. Roberts  D.P.J. Opperman 《African Journal of Range and Forage Science》2013,30(1):149-155

One of the main reasons for the poor acceptance of traditional veld management systems by South African farmers is the inflexibility of these systems. Present recommendations indicate that both research and extension personnel appreciate the advantages of the recently‐developed multicamp approach. Within this framework special attention should now be paid to policy relating to selective grazing, key species and proper use factors. Local studies on nutritive value and the relationship between height of defoliation and percentage utilization, emphasize the importance of the choice of key species. A generalized use factor of 50% removal in the growing season is proposed as an interim guide for grassveld management. The need for simplification of recommendations is emphasized.  相似文献   

Ranking of grass species according to visible wilting order and rate of recovery in the central orange free state     

H.A. Snyman  W.D. Venter  W.L.J. van Rensburg  D.P.J. Opperman 《African Journal of Range and Forage Science》2013,30(2):78-81

Abstract

A number of grasses were ranked according to the order in which they wilted with diminishing moisture availability, and according to their ability to recover after water replenishment. Digitaria eriantha and Digitaria argyrograpta were the most sensitive to moisture stress, whereas Sporobolus fimbriatus and Panicum stapfianum were last to show signs of wilting. The latter two grass species were the first to recover from wilting during optimum soil water conditions. The leaf water potential and soil water content at which each grass species wilted were recorded.  相似文献