Cytokine mRNA profiles in pigs exposed prenatally and postnatally to Schistosoma japonicum     

Techau ME  Johansen MV  Aasted B  Lind P  Ornbjerg N  Oswald IP 《Veterinary research》2007,38(1):25-36

The pig is a natural host for Schistosoma japonicum and a useful animal model of human infection. The aim of the present study was to assess the differences between the cytokine profiles in prenatally or postnatally S. japonicum exposed pigs. Seven prenatally exposed pigs, 7 postnatally exposed pigs and 4 uninfected control pigs were compared 27 weeks post exposure. Variables included worm burdens, tissue egg counts, liver pathology and mRNA levels of IL-2, IL-4, IL-10, IL-12, TNF-alpha, TGF-beta1 and IFN-gamma in the liver and the caecum, assessed by RT-PCR. Infection intensity and level of septal fibrosis were significantly higher in the postnatal group compared to the prenatal group (P < 0.05). A significant increase of IL-4 (P < 0.01), IL-10 (P < 0.01), IL-12 (P < 0.01) and TNF-alpha (P < 0.05) mRNA level was also observed in the caecum of prenatally infected animals compared to the control group (P < 0.01). The prenatal group showed higher levels of TGF-beta1 in the liver compared with the postnatally infected group (P< 0.05) and the control group (P< 0.01). This suppressive immune response correlated with previously reported low hepatic pathogenesis in prenatally exposed pigs.  相似文献   

Using morphometrics to identify sex in the eastern blue-tongued skink (Tiliqua scincoides)     

A Bird  D Monks  IP Hughes 《Australian veterinary journal》2023,101(7):282-290

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Presence of pap-, sfa-, and afa-related sequences in necrotoxigenic Escherichia coli isolates from cattle: evidence for new variants of the AFA family.          下载免费PDF全文

J G Mainil  E Jacquemin  F Hérault    E Oswald 《Canadian journal of veterinary research》1997,61(3):193-199

Necrotoxigenic Escherichia coli (NTEC) are associated with intestinal and extraintestinal diseases in animals and human beings and produce Cytotoxic Necrotizing Factor 1 (CNF1) or 2 (CNF2). Fourty-three NTEC1, 42 NTEC2, and 32 CNF-negative isolates from cattle were tested by colony DNA hybridization, by plasmid DNA hybridization and by PCR assays for the presence of DNA sequences homologous to the operons coding for fimbrial (PAP/PRS, SFA/FIC, and F17) and afimbrial (AFA/Dr) adhesins of extraintestinal E. coli. Most NTEC1 isolates hybridized with the PAP probes and either the SFA probe (37%) or the AFA probes (49%). Most NTEC2 isolates, in contrast, hybridized with the F17 probe (45%), the AFA probes (19%), or the F17 and AFA probes (22%). A probe-positive plasmid was identified in each of the 19 NTEC2 isolates studied. They all hybridized with the CNF2 toxin probe (Vir plasmids) and most of them with the F17 (6 plasmids) or AFA (7 plasmids) probes. PCR amplification was obtained with 6 of the 11 NTEC isolates tested for the papGII/prsG genes; with all 5 NTEC isolates tested for the sfa and related operons; but with none of the 18 NTEC isolates tested for the afa and related operons. pap-, sfa-, and afa-related sequences are thus present in NTEC isolates from cattle in addition to f17-related operons and may code for adhesins corresponding to specific colonization factors. f17- and afa-related sequences can be located on the Vir plasmids along with the cnf2 gene. Existence of new variants of the AFA/Dr family is evident from the negative results of this family-specific PCR assay.  相似文献   

Nitrogen transformations in copper-contaminated soils and effects of lime and compost application on soil resiliency     

O. Kostov  Oswald Van Cleemput 《Biology and Fertility of Soils》2001,33(1):10-16

 A neutral and an acidic soil were treated with different doses (0–3,000 mg Cu kg^–1 soil as CuSO₄) of copper. The percentages of inhibition of nitrification in both soils varied from 5 to 97%, but for the N mineralization these percentages varied from 8 to 65%. The toxic effect of Cu for basal nitrification and N mineralization was assessed as critical. Nitrification was more sensitive than ammonification to copper toxicity. It appears that an ecological dose of inhibition for nitrification and N mineralization higher than 10% is suitable as an indicator for Cu contamination. Soil resiliency assessed by N mineralization in the lime treatments varied from 11 to 154% in the sandy soil and from 70 to 168% in the sandy loam soil. A combined application of lime and compost significantly increased soil resiliency. The percentage increase varied from 904 to 1,390% in the sandy soil and from 767 to 2,230% in the sandy loam soil. It appears that compost was a powerful agent for recovering the soil fertility of Cu-contaminated soils as assessed by N transformation. The acidic sandy soil showed a lower capacity for recovery after Cu toxicity stress. Received: 27 February 1999  相似文献   

Effects of predator hunting mode on grassland ecosystem function   总被引：1，自引：0，他引：1  

Schmitz OJ 《Science (New York, N.Y.)》2008,319(5865):952-954

The way predators control their prey populations is determined by the interplay between predator hunting mode and prey antipredator behavior. It is uncertain, however, how the effects of such interplay control ecosystem function. A 3-year experiment in grassland mesocosms revealed that actively hunting spiders reduced plant species diversity and enhanced aboveground net primary production and nitrogen mineralization rate, whereas sit-and-wait ambush spiders had opposite effects. These effects arise from the different responses to the two different predators by their grasshopper prey-the dominant herbivore species that controls plant species composition and accordingly ecosystem functioning. Predator hunting mode is thus a key functional trait that can help to explain variation in the nature of top-down control of ecosystems.  相似文献   

A CYLINDER GUIDE FOR USE IN PLATE ASSAY OF PENICILLIN     

Oswald EJ  Randall WA 《Science (New York, N.Y.)》1945,101(2613):99-100

A guide or template is described which facilitates placing the cylinders on the agar surface in the plate assay of penicillin. The general plan of conducting the assay is discussed and several advantages of the use of the guide are noted. We wish to thank Mr. Albert G. Sterling, instrument maker, for fabricating the guide and the aluminum cylinders.  相似文献   

Effect of dicyandiamide and hydroquinone on the transformation of urea-nitrogen-15 in soil cropped to wheat   总被引：2，自引：0，他引：2  

Xingkai Xu  Yao Huang  Likai Zhou  Guohong Huang  Oswald Cleemput 《Biology and Fertility of Soils》2001,34(4):286-290

A pot experiment with a loam soil and spring wheat as test crop showed that an application of dicyandiamide (DCD), and especially its combination with hydroquinone (HQ), gave a much larger recovery of soil urea-¹⁵N than treatments based on the application of urea alone or urea plus HQ. Most of the urea-¹⁵N applied to soil was present as organic plus chemically fixed ¹⁵N in the DCD and DCD plus HQ treatments. These two treatments showed the smallest accumulation of urea-derived (NO₃^-+NO₂^-)-¹⁵N. Under well-drained conditions, there was a synergistic effect of the nitrification inhibitor DCD and the urease inhibitor HQ on urea-¹⁵N transformations and the recovery of fertilizer ¹⁵N in soil after the application of urea.  相似文献   

Detection of Escherichia coli strains producing cytotoxic necrotizing factor type two (CNF2) by enzyme-linked immunosorbent assay     

Eric Oswald  Marc Tabouret  Roger Boivin  Jean De Rycke 《Veterinary microbiology》1994,40(3-4):209-218

Sheep and rabbit antisera were produced against lysates of E. coli strain 711 (pVir). This K-12 strain carries the Vir plasmid which codes for Cytotoxic Necrotizing Factor type 2 (CNF2). Immunoglobulin G (IgG) fractions of both immune sera were subsequently purified by a two-step precipitation method. To increase the specificity for CNF2, the sheep IgG preparation was extensively adsorbed against both a sonicated extract of isogenic K-12 strain 711 and intact phenol-treated cells of vaccine strain 711 (pVir). An enzyme-linked immunosorbent assay (ELISA) was developed to detect clinical isolates of E. coli producing CNF2, using the final preparations of rabbit and sheep IgG in a double sandwich technique. The results obtained with this CNF2-ELISA were compared to those obtained with the conventional HeLa cell cytotoxicity assay. The testing of 133 E. coli strains (49 CNF2 positive strains and 84 negative strains) resulted in no false-negative and no false-positive. Therefore, the CNF2-ELISA offers a good alternative to the HeLa cell culture assay for the detection of CNF2-producing strains where facilities for and experience with cell cultures is lacking.  相似文献   

Ingestion of low doses of deoxynivalenol does not affect hematological, biochemical, or immune responses of piglets     

Accensi F  Pinton P  Callu P  Abella-Bourges N  Guelfi JF  Grosjean F  Oswald IP 《Journal of animal science》2006,84(7):1935-1942

Deoxynivalenol (DON), a mycotoxin produced by Fusarium spp., is a frequent contaminant of cereals. Because of their rich cereal diet, pigs could be exposed to this mycotoxin. Pigs are among the animal species showing the greatest sensitivity to DON. Effects of intermediate to high levels of DON on pigs are well known and include feed refusal, decreased feed intake, and alteration of the immune response. Effects of low levels of DON, which are commonly detected in contaminated feed, remain unknown. The aim of this study was to investigate the effect of a diet naturally contaminated with a low concentration of DON (0, 280, 560, or 840 microg/kg of feed) on performance of weanling piglets and on 34 hematological, biochemical, and immune variables. Low doses of DON did not alter the animal performances (feed intake and BW gain). Such low levels of DON did not modify the 9 hematological variables measured (including white blood cell, red blood cell, and platelet counts, relative numbers of neutrophils and lymphocytes, and hematocrit and hemoglobin concentrations) or the 18 biochemical variables tested (including cations, glucose, urea, creatinine, bilirubin, cholesterol and triglyceride concentrations, and plasma enzyme activity). Similarly, no effect of low doses of DON was observed on the immune responses of the animals (immunoglobulin subset concentration, lymphocyte proliferation, and cytokine production).  相似文献   

Role of intestinal epithelial cells in the innate immune defence of the pig intestine   总被引：4，自引：0，他引：4  

Oswald IP 《Veterinary research》2006,37(3):359-368

The intestinal epithelium serves as a dynamic barrier, which in the course of its normal function, maintains regulated uptake of nutrients and water while excluding potential pathogens. Over the past decade many studies have also revealed the immunological importance of intestinal epithelial cells (IEC). IEC have developed a variety of mechanisms to reduce the risk of infection by invasive pathogens or damage by toxic compounds. The effective maintenance of a physical barrier function is dependent on the establishment of well-organised intercellular junctions and a constant state of regeneration/renewal of the epithelium. IEC also participate in the innate immune responsiveness of the intestine by their ability to secrete mucus and antimicrobial peptides. IEC are also able to secrete cytokines and to respond to exogenous chemokines. This review summarises the current knowledge of the innate immune mechanisms developed by porcine IEC.  相似文献