Pretreatment of guinea-pigs with iron or desferal influences the course of Yersinia enterocolitica infections     

Nikolova S  Wesselinova D  Vesselinova A 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2001,48(3):167-178

The effects of iron excess and desferrioxamine in pretreated guinea-pigs on the immune response (production of Yops) and on the histological changes in infections with Yersinia enterocolitica 0:3 and Y. enterocolitica 0:8 were investigated. The prior overload of the guinea pigs with Dextrofer or treatment with Desferal increased the pathogenic activity of Y. entercolitica 0:3 and led to a generalized infection. Immunoblot analysis showed that in conditions of iron overload the expression of outer membrane proteins (Yops) of Y. enterocolitica 0:8 was blocked. This was accompanied by weak changes in the tissues. The iron limited conditions stimulated production of a low molecular weight protein (17 kDa) on day 6 and easier proliferation of the bacterium. This in vivo study intends to show that in Y. enterocolitica infections a leading role is played not only by iron itself but also by the bacterial strain.  相似文献   

Arthritis after experimental infection with Yersinia enterocolitica 0:3 in rabbits     

Vesselinova A  Najdenski H  Nikolova S  Wesselinova D 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2001,48(1):43-53

Arthritis in rabbits was caused after experimental oral infection with Yersinia enterocolitica (serotype 0:3, biotype 4, pYV+). Clinical and laboratory signs, bacterial dissemination to the viscera, immune response and morphological findings were studied from day 1 to day 40 post-infection (p.i.). Augmentation of body temperature and erythrocyte sedimentation rate occurred on day 1, and on day 8 p.i. was accompanied by leucopenia. The number of alveolar macrophages was increased up to the 15th day p.i., in contrast to peritoneal macrophage numbers. Extensive bacterial colonization of the internal organs was detected at necropsy until the end of the experiment. Analysis of the cell immune response revealed activation of B cells in peripheral blood, spleen and thymus as well as augmentation of T-cell number in the lymphoid organs examined on days 15, 28 and 40 p.i. Histological changes typical of a generalized infection, such as purulent meningoencephalitis, catarrhal pneumonia and lymphadenitis, were observed. Clinical and morphological manifestations of arthritis were also established. The results obtained show that Y. enterocolitica (serotype 0:3, pYV+) induces a generalized, non-lethal infection in Chinchilla rabbits, complicated by arthritis.  相似文献   

Estimating “autotrophic” belowground respiration in spruce and beech forests: decreases following girdling     

Christian?P.?Andersen  Ivan?Nikolov  Petia?Nikolova  Rainer?Matyssek  Karl-Heinz?H?berleEmail author 《European Journal of Forest Research》2005,124(3):155-163

Seasonal fluxes of CO₂ from soil and the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) were estimated for a mixed stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) in Central Europe. Mature trees of each species were girdled in August 2002 to eliminate carbohydrate allocation to roots. SR was measured at distances of 0.5, 1.0, and 1.5/2.0 m from the bole of each tree at 1–2 weeks intervals throughout the fall of 2002 and monthly during the spring and summer of 2003. The contribution of roots and mycorrhizae to total SR was estimated by the decrease in SR compared to ungirdled control trees to account for seasonal patterns evident in controls. SR decreased with soil temperature in the fall 2002 and increased again in 2003 as soil warmed. During most of the study period, SR was strongly related to soil temperature. During the dry summer of 2003, however, SR appeared to be uncoupled from temperature and was strongly related to soil water content (SWC). Mean rates of SR in beech and spruce control plots as well as root densities did not show a clear pattern with distance from the bole. SR decreased to levels below controls in beech within a few days after girdling, whereas spruce did not show a significant decrease until October 2002, 6 weeks after girdling. In both beech and spruce, decreased SR in response to girdling was greatest closest to the bole, possibly reflecting increased mycorrhizal activity close to the bole. Autotrophic respiration was estimated in beech to be as much as 50% of the total SR in the stand. The contribution of autotrophic respiration was less certain for spruce, although close to the bole, the autotrophic fraction may contribute to total SR as much as in beech. The large fraction of autotrophic respiration in total SR requires better understanding of tree level stresses that affect carbon allocation below ground.  相似文献   

Consumer Versus Resource Control in Freshwater Pelagic Food Webs     

MT Brett  CR Goldman 《Science (New York, N.Y.)》1997,275(5298):384-386

Models predict that food-web structure is regulated by both consumers and resources, and the strength of this control is dependent on trophic position and food-web length. To test these hypotheses, a meta-analysis was conducted of 11 fish (consumer)-by-nutrient (resource) factorial plankton community experiments. As predicted, zooplankton biomass was under strong consumer control but was weakly stimulated by nutrient additions; phytoplankton biomass was under strong resource control with moderate control by fish. However, the phytoplankton and zooplankton responses to nutrient additions did not follow theoretical predictions based on the number of trophic levels in the food web.  相似文献   

Exogenous succinate increases resistance of maize plants to copper stress     

Snejana Doncheva  Zlatimira Stoyanova  Katya Georgieva  Dimitrina Nedeva  Rumyana Dikova  Grigor Zehirov  Ana Nikolova 《植物养料与土壤学杂志》2006,169(2):247-254

The effect of copper (Cu) excess (1.5, 4.7, 31, 78, 156 μM) and exogenously supplied succinate on plant growth, chlorophyll content, chlorophyll fluorescence, and isoenzym profiles of some antioxidant enzymes in maize plants was studied. Excessive Cu supply led to a reduction in the relative growth rate (RGR), tolerance index (TI), chlorophyll a and chlorophyll b contents, and the quantum yield of PSII electron transport in the light‐adapted state (ΦPSII). Copper treatment induced several changes in the anionic and cationic peroxidases (PODs), as well as superoxide dismutase (SOD) isoenzyme profiles. After 8 d of 78 μM–Cu treatment, two new anionic and two new cationic peroxidase isoenzymes in the roots were registered. Copper applied at concentrations above 31 μM resulted in higher levels of manganese superoxide dismutase (Mn‐SOD) in the roots and Cu,Zn‐superoxide dismutase (Cu,Zn‐SOD) in the leaves. However, the addition of Na‐succinate (200 μM) to the root medium prior to Cu treatment increased the capacity of the plants to partially overcome Cu toxicity.  相似文献   

Calculation of Terrestrial Inputs to Particulate Organic Carbon in an Anthropogenically Impacted Estuary in the Southeastern United States     

Eddins  Stefka G. Nikolova 《Water, air, and soil pollution》2001,127(1-4):227-241

Using ¹³C/¹²C ratios in particulate organic carbon(POC), this study evaluated the fraction of terrestrially derivedPOC in Winyah Bay, South Carolina, an anthropogenically impactedestuary in the southeastern United States. Results from themixing model, which should be viewed as an upper limit becauseof possible dilution from additional potential end-members,showed that between 50 and 90% of POC in the Winyah Bay estuaryis of terrestrial origin. As this POC may be associated withriver-transported pollutants, the potential for accumulation ofpollutants in Winyah Bay is high because POC may become trappedin the estuary as part of either estuarine bottom sediments,circulation or food webs. Thus strategies for pollutionmonitoring and control in the estuary and its watershed arenecessary for the future management of Winyah Bay naturalresources.  相似文献   

Pretreatment of Guinea‐pigs with Iron or Desferal Influences the Course of Yersinia enterocolitica Infections     

S. Nikolova  D. Wesselinova  A. Vesselinova 《Zoonoses and public health》2001,48(3):167-178

The effects of iron excess and desferrioxamine in pretreated guinea‐pigs on the immune response (production of Yops) and on the histological changes in infections with Yersinia enterocolitica 0:3 and Y. enterocolitica 0:8 were investigated. The prior overload of the guinea‐pigs with Dextrofer or treatment with Desferal increased the pathogenic activity of Y. enterocolitica 0:3 and led to a generalized infection. Immunoblot analysis showed that in conditions of iron overload the expression of outer membrane proteins (Yops) of Y. enterocolitica 0:8 was blocked. This was accompanied by weak changes in the tissues. The iron‐limited conditions stimulated production of a low molecular weight protein (17 kDa) on day 6 and easier proliferation of the bacterium. This in vivo study intends to show that in Y. enterocolitica infections a leading role is played not only by iron itself but also by the bacterial strain.  相似文献   

Evaluation of a regimen using a progesterone releasing intravaginal device (CIDR) and PMSG as a treatment for post partum anoestrus in dairy cattle     

TF. JUBB  P. BRIGHTLING  J. MALMO†  MT. LARCOMBE  GA. ANDERSON  SJ. HIDES‡ 《Australian veterinary journal》1989,66(10):334-336

Anoestrous dairy cows in seasonally calving herds in the Macalister Irrigation District of Gippsland, Victoria were treated at the start of the mating period with a progesterone releasing intravaginal device (CIDR). The CIDR was inserted for 7 days and 400 IU of PMSG was injected intramuscularly at removal. There was no clinically useful difference among cows receiving the CIDR, a placebo and untreated cows in the interval from treatment to either first oestrus or conception, the conception rate to first service or percent pregnant by the end of mating. Analyses of data from 2-year-old cows, older cattle, cows calved at least 45 days or cows calved at least 55 days and cows treated 3 weeks after the start of mating did not show improved reproductive performance following treatment with the CIDR.  相似文献   

Intrauterine Idiopathic Amputation of the Head of a Porcine Foetus     

JS Agerholm  MT Garoussi 《Reproduction in domestic animals》2013,48(3):e38-e40

An anencephalic full‐term porcine foetus accompanied by a mummified head was submitted for examination. The neck almost entirely lacked skin and was covered by granulation tissue as were the exposed parts of the spine and spinal cord. The case represents a rare case of intrauterine amputation. A definitive cause could not be established because the placenta was not available. The most likely cause is strangulation of the neck. Such strangulation could be due to a defect of the allantoamnion with herniation of the foetal head or entanglement by amniotic constriction bands.  相似文献   

Ultrastructure of the hydrophobic gastric surfactant barrier in the dog   总被引：1，自引：0，他引：1  

MT ETHELL  DR HODGSON  BA HILLS 《Australian veterinary journal》1999,77(4):240-244

OBJECTIVES: To confirm the hydrophobicity of the luminal surface of the canine stomach and to elucidate the ultrastructure of the lining imparting that property. DESIGN AND PROCEDURES: Gastric and duodenal mucosal samples from eight dogs were collected immediately after euthanasia and subjected to contact angle measurement using a goniometer. Other samples were examined by electron microscopy following a fixation procedure known to preserve phospholipids and oligolamellar structures. RESULTS: Contact angles for the canine gastric mucosal surface (85.1 +/- 5.5) were significantly greater (P < 0.0001) than for the duodenum (24.0 +/- 1.7). Electron microscopy revealed the existence of surfactant as abundant osmiophilic phospholipid material within the gastric and duodenal mucosae. CONCLUSION: We have confirmed the hydrophobic nature of the canine gastric mucosa whereas the luminal surface of the duodenum is hydrophilic. We propose that the water-repellent nature of the canine gastric lining contributes to the 'gastric mucosal barrier' and is imparted by an oligolamellar layer of surface-active phospholipid ('gastric surfactant') adsorbed to the surface. Both gastric and duodenal mucosae may also utilise phospholipids as an intercellular defense mechanism in the event that tight junctions are breached by acid. It is tempting to speculate that a deficiency of gastric phospholipids may predispose dogs to ulcers. Further, exogenous administration of phospholipids may be useful in preventing gastric ulceration.  相似文献