Influences of diet and vaccination on colonisation of pigs by the intestinal spirochaete Brachyspira (Serpulina) pilosicoli     

Hampson DJ  Robertson ID  La T  Oxberry SL  Pethick DW 《Veterinary microbiology》2000,73(1):75-84

The purpose of this study was to determine whether methods used to control swine dysentery (SD), caused by the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, would also be effective in controlling porcine intestinal spirochaetosis (PIS) caused by the related spirochaete Brachyspira (Serpulina) pilosicoli. Weaner pigs in Groups I (n=8) and II (n=6) received a standard weaner pig diet based on wheat and lupins, whilst Group III (n=6) received an experimental diet based on cooked white rice and animal protein. Pigs in Group II were vaccinated intramuscularly twice at a 3-week-interval with a formalinised bacterin made from B. pilosicoli porcine strain 95/1000 resuspended in Freund's incomplete adjuvant. Eleven days later pigs in all groups were infected orally with 10(10) cells of strain 95/1000 on three successive days. One control pig in Group I developed acute diarrhoea, and at post-mortem had a severe erosive colitis with end-on attachment of spirochaetes to the colonic epithelium. All other pigs developed transient mild diarrhoea and had moderate patchy colitis at post-mortem 3 weeks later. B. pilosicoli was isolated from the faeces of all pigs, except for one fed rice, and was isolated from the mesenteric nodes of three pigs from Group I and from one vaccinated pig in Group II. Consumption of the rice-based diet, but not vaccination, delayed and significantly (p<0.001) reduced the onset of faecal excretion of B. pilosicoli after experimental challenge. Vaccination induced a primary and secondary serological response to B. pilosicoli, as measured using sonicated whole cells of strain 95/1000 as an ELISA plate coating antigen. Antibody titres in the vaccinated pigs then declined, despite intestinal colonisation by B. pilosicoli. Both groups of unvaccinated animals also failed to develop a post-infection increase in circulating antibody titres.  相似文献   

Validation of RT‐PCR Assays for Molecular Characterization of Porcine Teschoviruses and Enteroviruses     

G. La Rosa  M. Muscillo  A. Di Grazia  S. Fontana  M. Iaconelli  M. Tollis 《Zoonoses and public health》2006,53(6):257-265

Porcine enteroviruses (PEVs) and teschoviruses (PTVs) are described as causative agents of neurological disorders, fertility disorders and dermal lesions of swine. Difficulties in the serological detection of these viruses may lead to a significant underestimation of infections with clinical symptoms. With the recent availability of genome sequence data for all the serotypes, molecular diagnosis is a possibility. The present study describes a new approach to molecular ‘serotyping’ of PTVs and PEV‐B viruses, involving the amplification and sequencing of a genomic fragment of the VP1 coding region. A molecular characterization of Italian entero‐teschovirus isolates was performed using a set of previously published and newly designed polymerase chain reaction primers. A total of 33 porcine isolates and 10 reference strains were analysed. Porcine enterovirus‐B samples were first diagnosed as positive for enterovirus by amplification of the 5′‐non‐translated region. Samples were then typed by amplification and sequencing of a portion of the VP1 coding region. Porcine enterovirus‐A and PTVs were detected by a published assay in the 5′‐NC region that allows them to be differentiated according to the size of amplification product, using the same set of primers. For serotype characterization of PTV, we evaluated four different regions: the N terminus of the capsid protein VP2, the region encoding for RNA‐dependent RNA polymerase, and the capsid VP1 and VP4 regions. The newly designed primers in the VP1 region was proved to be broad in range and suitable for serotype assessment and therefore constitute a useful diagnostic tool for molecular diagnosis of porcine teschovirus/enterovirus strains and for the study of molecular epidemiology and evolution of these viruses.  相似文献   

Identification and evaluation of chloroplast uni- and trinucleotide sequence repeats in citrus     

Ziniu Deng  Stefano La Malfa  Yuming Xie  Xingyao Xiong  Alessandra Gentile 《Scientia Horticulturae》2007

A cpDNA fragment of 34 genotypes belonging to Citrus and four related genera was amplified and sequenced. Chloroplast microsatellites were revealed with the length of repeats ranging from 25 to 44 bases. Other than the normal uninucleotide poly(A) repeats, a trinucleotide poly(TAA) motif was also found, the first report of such repeats in a plant chloroplast genome. According to SSR structure variations, 18 Chloroplast SSR Types (CST) were identified. The CST sequences were informative for better understanding the genetic relationships of chloroplast genomes among the analyzed genotypes and confirmed some previous hypotheses about the female parent of several hybrid accessions.  相似文献   

Molecular markers useful to discriminate <Emphasis Type="Italic">Coffea arabica</Emphasis> cultivars with high genetic similarity     

Tiago Vieira Sousa  Eveline Teixeira Caixeta  Emilly Ruas Alkimim  Antonio Carlos Baião de Oliveira  Antonio Alves Pereira  Laércio Zambolim  Ney Sussumu Sakiyama 《Euphytica》2017,213(3):75

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Biochemical characterization of Trichinella in Greenland     

G La Rosa  E Pozio  S A Henriksen 《Acta veterinaria Scandinavica》1990,31(3):381-383

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农田防护林更新树种选择及配置模式研究   总被引：5，自引：0，他引：5  

赵克昌  周腊虎 《防护林科技》2002,(3):14-17

对农田防护林更新树种和配置模式进行了分析研究。从新品种的引种上筛选出适于河西走廊发展的农田防护林树种为三倍体毛白杨B10 0 8和BT85 ,并能在瘠薄和盐碱化土壤上良好生长 ;经抗寒性分析得出垂柳、云杉、白榆、柽柳、沙枣抗冻性较强 ;为减缓天牛等蛀干害虫危害 ,在林网配置模式上引入了云杉、侧柏、樟子松、垂柳、小叶白蜡、国槐等耐瘠薄抗寒性强的树种 ,营造多树种林带 ,组成混交林网结构 ,使林网中感虫杨树的比例占 2 0 %左右 ,增加了林网结构的稳定性和长效性  相似文献   

The decline of Austrocedrus chilensis forests in Patagonia, Argentina: soil features as predisposing factors     

Ludmila La Manna  Mario Rajchenberg 《Forest Ecology and Management》2004,190(2-3):345-357

The forests of Austrocedrus chilensis in southern Argentina suffer mortality from “mal del ciprés”, whose causes remain unknown. The purpose of this work was to establish the relation of soil features with the occurrence of the disease. In Río Grande Valley, Chubut Province, Argentina, 14 areas with “mal del ciprés” were selected for study. The spatial pattern of the decline varied among the different areas and was classified as aggregated and disaggregated. In each area, symptomatic and asymptomatic plots were established and characterized by 11 edaphic and topographic variables. Three forest areas where the disease was totally absent were also included. Site features were related to the occurrence of the decline using principal component analysis and cluster analysis. Results indicated that soil properties related to poor internal drainage, such as the proximity to water streams, non-allophanized soils of fine textures, and redoximorphic features, act as predisposing factors to the development of “mal del ciprés”. Poor soil drainage was strongly associated not only with the occurrence of the disease, but also with its spatial pattern. Symptomatic and asymptomatic plots presented similar edaphic features in areas with a disaggregated distribution of the decline and were grouped together in the multivariate analysis. This result suggests that large areas with such a pattern are prone to develop the decline.  相似文献   

Micropropagation of Elaeagnus angustifolia from mature trees     

Iriondo JM  De La Iglesia M  Pérez C 《Tree physiology》1995,15(10):691-693

Multiple shoots were obtained from nodal segments of mature trees of Elaeagnus angustifolia L. cultured on MS medium (Murashige and Skoog 1962) supplemented with 0, 0.88 or 2.22 micro M N(6)-benzyladenine. When nodal segments taken from the in vitro proliferated shoots were cultured under the same conditions, additional multiple shoots were obtained. Rooting of the in vitro propagated shoots was achieved on full strength MS medium or on MS supplemented with 2.46 micro M indole-3-butyric acid. Regenerated plantlets were acclimatized and successfully transplanted to soil.  相似文献   

Determination of moisture content and basic specific gravity of Populus tremuloides (Michx.) and Populus balsamifera (L.) logs using a portable near-infrared spectrometer     

Guillaume Hans  Brigitte Leblon  Paul Cooper  Armand La Rocque  Joseph Nader 《Wood material science & engineering》2015,10(1):3-16

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Photoinhibition of photosynthesis in needles of two cypress (Cupressus sempervirens) clones     

La Porta N  Bertamini M  Nedunchezhian N  Raddi P  Muthuchelian K 《Tree physiology》2005,25(8):1033-1039

Photoinhibition of photosynthesis and photosynthetic recovery were studied in detached needles of cypress (Cupressus sempervirens L.) Clones 52 and 30 under controlled conditions of high irradiation (about 1900 micromol m(-2) s(-1) for 60 min; HL treatment), followed by 60 min in darkness. The degree of photoinhibition was determined based on the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm), which is a measure of the potential efficiency of photosystem II (PSII), and on electron transport measurements. The Fv/Fm ratio declined in needles of both clones in response to the HL treatment. Minimal fluorescence (Fo) increased in HL-treated needles of both clones. The HL treatment decreased rates of whole-chain and PSII activity of isolated thylakoids more in Clone 52 than in Clone 30. In needles of both clones, PSI activity was less sensitive to photoinhibition than PSII activity. In the subsequent 60-min dark incubation, fast recovery was observed in needles of both clones, with PSII efficiencies reaching similar values to those in non-photoinhibited needles. The artificial exogenous electron donors diphenyl carbazide (DPC), hydroxylamine (NH2OH) and manganese chloride (MnCl2) failed to restore the HL-induced loss of PSII activity in needles of Clone 30, whereas DPC and NH2OH significantly restored PSII activity in photoinhibited needles of Clone 52. Quantification of the PSII reaction center protein D1 and the 33-kDa protein of the water-splitting complex following HL treatment of needles revealed pronounced differences between Clone 52 and Clone 30. The large decrease in PSII activity in HL-treated needles was caused by the marked loss of D1 protein and 33-kDa protein in Clone 30 and Clone 52, respectively.  相似文献