Assessment of the antihistomonal effect of paromomycin and tiamulin     

van der Heijden HM  De Gussem K  Landman WJ 《Tijdschrift voor diergeneeskunde》2011,136(6):410-416

Histomonosis, a parasitic disease of galliformes and sporadically of other birds caused by Histomonas meleagridis, can result in very high mortality, especially in turkeys. The ban on the last antihistomonal drug prompted an urgent search for alternative prevention and treatment strategies. As both paromomycin and tiamulin have been reported to have antihistomonal activity, these antibiotics were investigated in vitro by adding two-fold serial dilutions ranging from 12.5 to 400 microg/mL to cultures of H. meleagridis. Controls (no antibiotics, or 12.5 microg or 400 microg/mL dimetridazole) were included. Parasites were counted after 3, 20, 28, 44, 51, and 71 hours of incubation. Tiamulin did not have a clear antihistomonal effect, but paromomycin had an inhibitory effect at all concentrations tested. The latter antibiotic was subsequently examined in an in vivo study. Five groups of 20 1-day-old poults, matched by weight and sex, were either not treated (infected and uninfected control groups) or treated with paromomycin (100, 200, or 400 ppm) added to their feed. After 2 weeks all groups, except for the uninfected control group, were intracloacally inoculated with 200,000 histomonads per bird. A clear dose-response effect was found for paromomycin. In the 100-ppm paromomycin group, mortality was similar to that in the untreated control group, whereas about half of the birds died in the 200-ppm paromomycin group; almost complete protection against histomonosis was seen in the 400-ppm paromomycin group. This study shows that paromomycin supplied in feed at 400 ppm is a potentially preventive strategy against H. meleagridis.  相似文献   

Charge migration in DNA: ion-gated transport     

Barnett RN  Cleveland CL  Joy A  Landman U  Schuster GB 《Science (New York, N.Y.)》2001,294(5542):567-571

Electron hole (radical cation) migration in DNA, where the quantum transport of an injected charge is gated in a correlated manner by the thermal motions of the hydrated counterions, is described here. Classical molecular dynamics simulations in conjunction with large-scale first-principles electronic structure calculations reveal that different counterion configurations lead to formation of states characterized by varying spatial distributions and degrees of charge localization. Stochastic dynamic fluctuations between such ionic configurations can induce correlated changes in the spatial distribution of the hole, with concomitant transport along the DNA double helix. Comparative ultraviolet light-induced cleavage experiments on native B DNA oligomers and on ones modified to contain counterion (Na(+))-starved bridges between damage-susceptible hole-trapping sites called GG steps show in the latter a reduction in damage at the distal step. This reduction indicates a reduced mobility of the hole across the modified bridge as predicted theoretically.  相似文献   

Serological detection of chicken flocks naturally infected with salmonella enteritidis,using an enzyme‐linked immunosorbent assay based on monoclonal antibodies against the flagellar antigen     

F.G. van Zijderveld  A.M. van Zijderveld‐van Bemmel  R.A.M. Brouwers  T.S. de Vries  W.J.M. Landman  W.A. de Jong 《The Veterinary quarterly》2013,33(4):135-137

Summary

The Dutch Salmonella enteritidis monitoring and eradication programme for poultry prescribes a periodic examination of all breeding flocks for the presence of S. enteritidis. For the first years of the programme this was done by bacteriological examination of 50 faecal samples per visit per flock.

In this study we compare the results of bacteriological examination of faecal samples taken at 1580 visits from 545 flocks with those of a S. enteritidis enzyme‐linked immunosorbent assay (ELISA) applied on 24 serum samples per visit per flock. Two flocks were found positive for S. enteritidis by bacteriological examination; both flocks were also detected by ELISA. Ten flocks, bacteriologically negative for S. enteritidis were found positive by ELISA. S. enteritidis was isolated from three of these flocks by repeated and extensive bacteriological examination for verification. Verification was not possible in the fourth EL1SA positive flock. S. enteritidis infections were likely in three other flocks because of the farm histories.

On the basis of the results of this study it was decided to use this ELISA, starting from April 1992, as screening technique in the Dutch S. enteritidis programme instead of bacteriological examination of faecal samples. The ELISA is regarded as a flock test; an extensive, confirmatory bacteriological investigation for S. enteritidis is carried out in ELISA positive flocks to decide whether the flocks are truly infected.  相似文献   

Molecular Cloning and Characterization of CD9 cDNA from Sheep and Cashmere Goat     

WJ Xing  LQ Wang  Q Wu  SC Ren  XH Bao  S Bou 《Reproduction in domestic animals》2010,45(3):383-392

CD9 is a glycoprotein of the transmembrane 4 superfamily (TM4SF) and is involved in various cellular processes. Some CD9 cDNA have been cloned in mammals and certain fish genera in recent years, but goat and sheep counterparts of cattle, human and mouse have not been identified. To facilitate the studies, we cloned the cDNA encoding for CD9 of cashmere goat (Capra hircus) and sheep (Ovis aries), and expressed sheep CD9 in Escherichia coli cells. Structural analysis indicated for both goat and sheep that a 1123 bp cDNA spanned an open reading frame of 681 bp which predicted a protein of 226 amino acids with a typical TM4SF structure, including four highly conserved transmembrane domains, two extracellular domains and a CCG motif, which is a hallmark of the TM4SF. The predicted amino acid sequences were highly homologous to those of cattle, mouse and human CD9. Molecular phylogenetic analysis based on CD9 cDNA sequences indicated that goat and sheep CD9 were closely related to CD9 of cattle, which is in agreement with their morphological taxonomy.  相似文献   

Early Meiotic‐Specific Protein Expression in Post‐natal Rat Ovaries     

P Zhang  LX Lv  WJ Xing 《Reproduction in domestic animals》2010,45(6):e447-e453

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Effect of anti-inflammatory drugs on colibacillosis lesions in broilers after Infectious Bronchitis Virus and subsequent Escherichia coli infection     

Landman WJ  Matthijs MG  van Eck JH 《The Veterinary quarterly》2012,32(1):25-29

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Study on the vertical transmission of arthropathic and amyloidogenic Enterococcus faecalis in a flock of brown layer chickens     

Landman WJ  Feberwee A  Veldman KT  Mevius DJ 《The Veterinary quarterly》2001,23(2):88-91

Enterococcus faecalis-related amyloid arthropathy was diagnosed in a sample of birds from a flock of brown layer parent chickens aged 57 weeks. E. faecalis was isolated from amyloidotic knee joints and from blood samples from lame birds. From this flock a smaller one was kept for production purposes to study the vertical transmission of arthropathic and amyloidogenic E. faecalis. Three batches of non-soiled and thoroughly disinfected eggs, to prevent egg-shell contamination, were collected for 6 weeks and submitted for incubation every 2 weeks. No joint pathology was found in the offspring chicks (n = 458) monitored for joint disease until 16 or 21 weeks of age. Fresh and candled eggs (infertiles and dead embryos) obtained at day 18 of the incubation period had negative results at bacteriological examination of the yolk sac, except one non-hatched egg (late embryonal death in shell) from which E. faecalis was isolated. Genotyping by pulsed-field gel electrophoresis (PFGE) of all E. faecalis isolates obtained from blood and joints (except one) of the parent birds and of the non-hatched egg after Sma I digestion showed that all isolates were genetically closely related or identical to a known arthropathic and amyloidogenic E. faecalis strain. In this study, vertical transmission of E. faecalis, although it may occur on a small scale as shown by PFGE, did not seem to play a significant role. Conversely, the chronicity of the condition and the development of an immune response may have affected the efficiency of its transmission.  相似文献   

Aerosolization of Newcastle disease vaccine virus and Enterococcus faecalis     

Landman WJ  van Eck JH 《Avian diseases》2001,45(3):684-687

In order to study the aerosol transmission of arthropathic and amyloidogenic Enterococcus faecalis strains, preliminary aerosol experiments were performed. The experiments were carried out in empty isolators to assess the yield and viability of E. faecalis and Newcastle disease vaccine virus (NDVV) aerosol particles with time. NDVV was aerosolized because this virus would be used in combination with E. faecalis in a subsequent study. Concentrations of about 10(5) colony-forming units (CFU) of E. faecalis/ml of air were still found 30 min after the aerosol application. At 45 min, however, E. faecalis concentrations dropped below the detection level. The average E. faecalis concentration during the aerosol experiment was estimated at 10(5) CFU/liter. The NDVV aerosol generated an average of 10(4)-10(5) 50% embryo infective dose per liter of air. In these experiments, E. faecalis and NDVV aerosols were successfully generated despite considerable initial particle loss. The bacteria and virus uptakes per chick are discussed in case day-old chicks would be exposed to these aerosols.  相似文献   

Ways to Improve the Biosecurity of Bovine Semen     

L de Ruigh  JC Bosch  MC Brus  B Landman  JS Merton 《Reproduction in domestic animals》2006,41(4):268-274

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Leukocyte responses in two breeds of layer chicken that differ in susceptibility to induced amyloid arthropathy     

Zekarias B  Landman WJ  Tooten PC  Gruys E 《Veterinary immunology and immunopathology》2000,77(1-2):55-69

Amyloid arthropathy in chicken can be induced by intravenous inoculation of an arthropathic and amyloidogenic Enterococcus faecalis in susceptible breeds. The commercial brown layer hybrids (BL) are more susceptible to the disease compared to their white counterparts (WL). The precursor of amyloid-A protein, which is serum amyloid-A (SAA), is identical in WL and BL. To investigate the factors involved in the breed-restricted susceptibility to amyloid arthropathy, we studied the type of leukocyte response and inflammatory reactions in E. faecalis-induced disease. In the BL, a significant dose dependent peripheral leukocytosis mainly by heterophils, and plasma cell infiltration in arthritic joints was found. In contrast, secondary lymphoid nodular aggregates in the synovial membrane were prominent in the WL. The aggregates consisted mainly of CD8+ T cells. The high number of circulating leukocyte and prolific plasma cell responses in the BL predict extensive humoral and acute phase reactions. This is in agreement with literature data on suppressed T-cell function in casein-induced amyloid-susceptible mice strains. The difference in leukocyte response and type of inflammation between WL and BL, when arthropathic and amyloidogenic bacteria induce infection, in conjunction with susceptibility to amyloid arthropathy, is discussed in view of the murine T-helper responses.  相似文献