Aerial Transmission of Thielaviopsis basicola, a Pathogen of Corn-Salad, by Adult Shore Flies     

Stanghellini ME  Rasmussen SL  Kim DH 《Phytopathology》1999,89(6):476-479

ABSTRACT Chlamydospores of Thielaviopsis basicola were consistently observed in frass excreted by adults and larvae of shore flies that were collected in the immediate vicinity of naturally infected corn-salad plants obtained from a commercial greenhouse production facility. Approximately 95% of the adult flies and 85% of the larvae were internally infested with the pathogen. Pathogen-free adult shore flies were subsequently shown to acquire the pathogen by ingestion after feeding on naturally infected plants. Viable propagules of the pathogen were excreted by these internally infested adults and were capable of transmitting the pathogen to healthy seedlings, which subsequently became infected.  相似文献   

Investigations on the Influence of Helminth Parasites on Vaccination of Chickens against Newcastle Disease Virus under Village Conditions     

Hørning G  Rasmussen S  Permin A  Bisgaard M 《Tropical animal health and production》2003,35(5):415-424

Prevalence studies have shown that almost 100% of free-range chickens are infected with a wide range of parasites. The infections are mostly subclinical in nature, resulting in production losses and occasionally mortality. Newcastle disease (ND), on the other hand, results in high mortality rates during epidemics. ND is a limiting factor for increasing poultry production in many tropical countries, where frequent reports indicate vaccination failures. The aim of our study was to investigate the influence of helminths on the antibody response after vaccination against Newcastle disease of free-range chickens naturally infected with parasites. Sixty chickens were divided into six groups, of which three were vaccinated against ND with a live De Soto vaccine, while the other three remained non-vaccinated. One group within the vaccinated groups and the one within the non-vaccinated group was kept naturally infected with helminth parasites, while the other two groups in each set were dewormed with fenbendazole and niclosamide, and one of each of these groups was subsequently infected with Ascaridia galli. After vaccination, all the groups were followed for 5 weeks and their antibody titres were determined weekly using a HI test. All the birds were finally challenged 4 weeks after vaccination with a virulent velogenic ND virus obtained from a field outbreak. All the vaccinated chickens seroconverted and had high antibody levels after 3 weeks, but these dropped to low levels at 4 weeks after vaccination. After challenge, the antibody titres rose in the dewormed groups but not in the parasite-infected groups. After 5 weeks, all the parasite-infected animals had significantly lower antibody titres than the dewormed animals. All the vaccinated chickens survived the challenge infection, emphasizing the importance of the cellular immune response. Further studies are needed to examine the effects of the parasitic infection on protection against ND over a longer period.  相似文献   

Cytotoxic constituents of Alectra and Striga species     

C Rank  L S Rasmussen  S R Jensen  S Pierce†  M C Press‡  & J D Scholes‡ 《Weed Research》2004,44(4):265-270

Decimation of cereal growth and yields by hemiparasitic Striga species cannot be accounted for entirely by the removal of host‐plant resources. The production of toxic compounds by the parasite has been suggested. An investigation of three species of the economically important Striga and the related Alectra vogelii has now resulted in the isolation of eight iridoid glucosides (mussaenosidic acid, mussaenoside, gardoside methyl ester, bartsioside, isoaucubin, melittoside, aucubin and eurostoside), two caffeoyl phenylethyl glycosides (calceolarioside  A and verbascoside) as well as shikimic acid and trigonelline, all identified by NMR spectroscopy. The iridoids are potent cytotoxins and probably represent an anti‐herbivore defence system common to Scrophulariaceae (sensu lato). This has the potential to explain differences in tolerance apparent for contrasting host taxa and cultivars. The nature of the iridoids present also provides additional validation of the recent transferral of parasitic Scrophulariaceae (s.l.) to Orobanchaceae.  相似文献   

Skin grafting and graft rejection in goats.     

R H van Dam  R Boot  J A van der Donk  J Goudswaard 《American journal of veterinary research》1978,39(8):1359-1362

As part of a study to define the major histocompatibility complex of the goat and to show certain aspects of its biological function, a skin-grafting technique is described which might also be applicable for similar studies in other ruminant species.  相似文献   

Effects of dietary starch and energy levels on maximum feed intake, growth and metabolism of Nile tilapia, Oreochromis niloticus     

An Tran-Duy  Ben Smit  Anne A. van Dam  Johan W. Schrama 《Aquaculture (Amsterdam, Netherlands)》2008,277(3-4):213-219

The aim of this study was to gain insight into how Nile tilapia (Oreochromis niloticus) regulate feed and energy intake in response to diets low and high in starch and cellulose. It was hypothesized that high-starch diets would reduce feed intake due to the effect of high blood glucose level, and that stomach volume may limit feed intake of fish fed diets low in energy. Four experimental diets, low starch–no cellulose inclusion, high starch–no cellulose inclusion, low starch–with cellulose inclusion, and high starch–with cellulose inclusion, were formulated. The high-starch diets and diets with cellulose inclusion were 17.5% more energy-diluted than the low-starch diets and diets without cellulose inclusion, respectively. Male tilapia were fed to apparent satiation for six weeks. Feed and digestible energy intake of fish fed diets with cellulose inclusion increased and decreased by 8.3% and 5.5%, respectively, compared to fish fed diets without cellulose inclusion. This suggests the role of stomach volume in restricting feed consumption. Fish fed high-starch diets achieved only 0.5% more feed intake and 13.9% less digestible energy intake than fish fed low-starch diets. The lower increase in feed intake and higher decrease in digestible energy intake of fish fed high-starch diets than of fish fed diets with cellulose inclusion suggests that high blood glucose suppresses feed intake in Nile tilapia. An alternative explanation for the differences in feed and digestible energy intake of fish fed different diets was based on the fact that heat production was not influenced by starch nor cellulose-inclusion levels. Thus, under satiation feeding, oxygen uptake capacity may determine feed and digestible energy intake in fish rather than blood glucose or stomach volume.  相似文献   

Airborne heavy metal pollution in the environment of a danish steel plant     

N. K. Vestergaard  U. Stephansen  L. Rasmussen  K. Pilegaard 《Water, air, and soil pollution》1986,27(3-4):363-377

A survey of heavy metal deposition was carried out in the vicinity of a Danish steel plant. Bulk precipitation and transplanted lichen (Hypogymnia physodes (L.) Nyl.) were sampled at 12 stations in the environment before and after the production had been converted from open-hearth furnaces to electric-arc furnaces. The samples were analyzed for Cd, Cr, Cu, Fe, Mn, Pb and Zn. The results show that heavy metal pollution from the steelworks still is severe and that it follows a decreasing power curve when the distance to the steelworks is increased. However, a reduction in the deposition of heavy metals close to the steelworks has been observed, pointing to the conclusion that the change from a situation of emission through a 46 m stack without any filter to emission from the electric arc furnaces equipped with bag-filters has lead to changes in the emission. At the sampling stations with the highest deposition levels measured in bulk precipitation the corresponding concentrations in the lichens were relatively lower indicating a change in particle size distribution. Within each station there was a direct proportionality of metal concentrations in lichens and atmospheric fallout measured in bulk precipitation.  相似文献   

Population Genetic Analysis of a Global Collection of Pyrenophora tritici-repentis, Causal Agent of Tan Spot of Wheat     

Friesen TL  Ali S  Klein KK  Rasmussen JB 《Phytopathology》2005,95(10):1144-1150

ABSTRACT The work presented here is the first major study to analyze the genetic diversity within the worldwide population of the economically important wheat pathogen Pyrenophora tritici-repentis. The genetic structure of field populations of P. tritici-repentis was determined using amplified fragment length polymorphism markers along with sequence data from the internal transcribed spacer region of the ribosomal DNA. Ninetyseven fungal isolates were collected from naturally infected wheat and wild grass species. The collection of 97 P. tritici-repentis isolates included races 1, 2, 3, 4, 5, ND7, and ND8 and was collected from North America, South America, and Europe. Results show no genetic grouping of fungal races nor do results indicate grouping based on geographic location indicating that the population is preferentially outcrossing in nature and that the introduction and spread of this population is either relatively recent or that there has been a constant worldwide flow of this fungus possibly by seed movement between continents.  相似文献   

An enzootic of pulmonary tuberculosis in pigs caused by M. avium. 2. Bacteriological studies   总被引：2，自引：0，他引：2  

J B Jorgensen  H C Engbaek  A Dam 《Acta veterinaria Scandinavica》1972,13(1):68-86

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Half-lives of sulphadoxine and trimethoprim after a single intravenous infusion in cows   总被引：1，自引：0，他引：1  

D Davitiyananda  F Rasmussen 《Acta veterinaria Scandinavica》1974,15(3):356-365

DAVITIYANANDA, DANIS and FOLKE RASMUSSEN: Half-lives of sulphadoxine and trimethoprim after a single intravenous infusion in cows. Acta vet. scand. 1974, 15, 356–365. — The half-life of sulphadoxine in plasma (11 hrs.) is much longer than that of trimethoprim (50–103 min.) and in accordance to this traces of sulphadoxine are demonstrated in the milk 3 days after the infusion, while trimethoprim could not be detected in milk 2 days after the infusion. The apparent volume of distribution is 0.37 for sulphadoxine and 1.14 for trimethoprim, i.e. 37 % and 114 % of the body weight, respectively.sulphadoxine; trimethoprim; half-life; cow.  相似文献   

Mammary excretion of lincomycin in cows   总被引：1，自引：0，他引：1  

F Rasmussen 《Acta veterinaria Scandinavica》1966,7(1):97-98

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