A syndrome of hereditary tyrosinemia in mink (Mustela vison Schreb.).          下载免费PDF全文

K Christensen  P Fischer  K E Knudsen  S Larsen  H Srensen    O Venge 《Canadian journal of veterinary research》1979,43(3):333-340

A hereditary disease in mink (Mustela vison Schreb.) leading to death when the affected kits are about six weeks old has been investigated. The disorder is inherited as a simple autosomal recessive character. Strongly elevated plasma tyrosine concentration is an outstanding feature of the disease. An enzyme defect in tyrosine aminotransferase (EC 2.6.1.5) or 4-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27) is considered together with the possibility of a parallel between the disease in mink and the disease tyrosinosis or hereditary tyrosinemia in man.  相似文献   

A review of the criteria used to assess insensibility and death in hunted whales compared to other species     

Knudsen SK 《Veterinary journal (London, England : 1997)》2005,169(1):42-59

This review addresses the diagnosis of insensibility and death in various species so as to evaluate the validity of the current criteria used to judge death in hunted whales by the International Whaling Commission (IWC). The only other species in which official criteria of death have been formulated is humans and these are controversial with the kernel of the debate being the definition of brain death. In slaughter animals, the moment of insensibility is regarded as the most important criterion and the issue has received scientific interest related to the pre-slaughter stunning. During hunting of terrestrial wildlife, the moment of death is usually regarded as the moment the animal falls and does not move. Based on the data presented in the present paper, it is concluded that when death in whales is solely determined on the basis of the IWC criteria, which in practice are based on immobility, a significant proportion of animals will be recorded as being sensible and alive when they are actually unconscious and the time to death (TTD) will be overestimated. If the criteria are used in conjunction with a postmortem examination, the recorded TTD will be closer to the real TTD and can be used for comparison of methods and performance.  相似文献   

Use of Green Fluorescent Protein and Image Analysis to Quantify Proliferation of Trichoderma harzianum in Nonsterile Soil     

Orr KA  Knudsen GR 《Phytopathology》2004,94(12):1383-1389

ABSTRACT One drawback of traditional methods for fungal biomass measurement is the inability to distinguish biomass of an introduced fungus from that of the indigenous microbial community in nonsterile soil. We quantified biomass of a specific fungal biological control agent in nonsterile soil using epifluorescence microscopy and image analysis of green fluorescent protein (GFP)-expressing Trichoderma harzianum (ThzID1-M3). Numbers of colony forming units on a semiselective medium were compared with biomass estimates from image analysis, after ThzID1-M3 was incubated in soil that either remained moist (-0.05 MPa) for 14 to 21 days or remained moist for approximately 5 days and then was allowed to dry to <-3.0 MPa. Recovery of significant numbers of ThzID1-M3 propagules lagged approximately 3 days behind initiation of hyphal growth. Reductions in both colony counts and biomass were observed over time when soil was allowed to dry. However, in soil that remained moist, colony counts increased over a 14- to 21-day period even though biomass declined after approximately 3 to 5 days. Our results confirm that use of GFP, along with epifluorescence microscopy, is a useful tool to distinguish active hyphal biomass, the form of the fungus that is functional for biological control, from inactive propagules such as conidia or chlamydospores that are enumerated by plate counts.  相似文献   

Influence of a Fungus-Feeding Nematode on Growth and Biocontrol Efficacy of Trichoderma harzianum     

Bae YS  Knudsen GR 《Phytopathology》2001,91(3):301-306

ABSTRACT A fungivorous nematode, Aphelenchoides sp., was isolated from field soil by baiting with mycelium of the biocontrol fungus Trichoderma harzianum ThzID1, and subsequently was maintained on agar cultures of the fungus. Interactions between the nematode and the green fluorescent protein-producing transformant, T. harzianum ThzID1-M3, were investigated in both heat-treated (80 degrees C, 30 min) and untreated field soil. ThzID1-M3 was identified in soil by epifluorescence microscopy. When ThzID1-M3 was added to soil as an alginate pellet formulation, addition of the nematode (10 per gram of soil) significantly reduced radial growth and recoverable populations of the fungus, and the effect was greater in heat-treated soil than in untreated soil. Addition of ThzID1-M3 to soil pretreated with the nematode (10 per gram of soil) stimulated nematode population growth for approximately 10 to 20 days, whereas nematode populations decreased in the absence of added Trichoderma sp. When sclerotia of Sclerotinia sclerotiorum were added to soil (10 per 200 g of soil) with ThzID1-M3 (40 pellets per 200 g of soil), addition of Aphe-lenchoides sp. (2,000 per 200 g of soil) reduced the number of sclerotia colonized by ThzID1-M3. These results suggest that fungivorous nematodes may be a significant biotic constraint on activity of biocontrol fungi in the field.  相似文献   

Biological Seed Treatment of Cereals with Fresh and Long-term Stored Formulations of Clonostachys rosea: Biocontrol Efficacy Against Fusarium culmorum     

Birgit Jensen  Inge M.B. Knudsen  Dan Funck Jensen 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(3):233-242

In six field experiments, seed treatment with Clonostachys rosea (IK726) significantly reduced disease caused by Fusarium culmorum. IK726 was active against the pathogen at average soil temperatures at sowing ranging from 6.2 to 12 °C. Both in the field experiments and in growth chamber experiments conducted in sand, dried and stored conidia of IK726 controlled F. culmorum as effectively as freshly harvested conidia. A high correlation was found between disease index ratings from field experiments and from corresponding growth chamber sand tests. Amendment with the stickers Pelgel or Sepiret did not influence control activity. The effective dosages of IK726 (cfu/seed) were estimated in bioassays and were very similar for freshly harvested conidia and for dried conidia. With a density of > 5×10³ conidia per seed more than 80% disease control was repeatedly obtained with both types of conidia.  相似文献   

Visual instruction of the neural map of auditory space in the developing optic tectum   总被引：1，自引：0，他引：1  

E I Knudsen  M S Brainard 《Science (New York, N.Y.)》1991,253(5015):85-87

Neural maps of visual and auditory space are aligned in the adult optic tectum. In barn owls, this alignment of sensory maps was found to be controlled during ontogeny by visual instruction of the auditory spatial tuning of neurons. Large adaptive changes in auditory spatial tuning were induced by raising owls with displacing prisms mounted in spectacle frames in front of the eyes; neurons became tuned to sound source locations corresponding to their optically displaced, rather than their normal, visual receptive field locations. The results demonstrate that visual experience during development calibrates the tectal auditory space map in a site-specific manner, dictating its topography and alignment with the visual space map.  相似文献   

The suitability of anadromous Arctic charr as host and vector of the monogenean Gyrodactylus salaris     

R. Knudsen  P. Adolfsen  S. Sandring  R. Kristoffersen  S. Siikavuopio  A. Rikardsen 《Ecology of Freshwater Fish》2007,16(1):99-104

Abstract –  In 2000, the Atlantic salmon ( Salmo salar L.) stock in the river Signaldalselva, North Norway was found to be infected with the monogenean Gyrodactylus salaris (Malmberg). This river system has a multispecies fish community of nine species in total. Low densities of Atlantic salmon parr were found during electrofishing in October (2003) with a prevalence of 94% and a mean abundance of 848 G. salaris. This watercourse also holds a riverine stock of anadromous Arctic charr ( Salvelinus alpinus ), which is not common in Norway. Among the parr of Arctic charr, 64% were infested with an abundance of 23 parasites per fish. The most heavily infected 0+ and 1+ juvenile Arctic charr had 469 and 534 parasites, respectively, indicating that the parasites are able to reproduce on Arctic charr in the wild. There was little variation in the rates of infestation of Arctic charr along the studied stretch of the river, even in areas with very low densities of Atlantic salmon parr. The parr of anadromous Arctic charr seem to be suitable as long-term hosts for G. salaris . Moreover, a few (22%) infested adult sea-running Arctic charr were captured after ascending the river in the autumn, which shows that large fish may also act as carriers of G. salaris . However, no parasites were recorded on potential anadromous Arctic charr before descending during early spring (April 2003 and April 2004). Thus, it is still not clear whether anadromous Arctic charr are able to disperse the parasite between watercourses. So far, it is uncertain whether G. salaris may increase the mortality rates of Arctic charr and thereby be a threat to these unusual occurring riverine anadromous Arctic charr stocks.  相似文献   

Stress-induced changes in the affinity and abundance of cytosolic cortisol-binding sites in the liver of rainbow trout,Oncorhynchus mykiss (Walbaum), are not accompanied by changes in measurable nuclear binding     

T. G. Pottinger  F. R. Knudsen  J. Wilson 《Fish physiology and biochemistry》1994,12(6):499-511

Plasma cortisol levels and the number (N_max) and affinity (K_d) of specific hepatic cortisol-binding sites were determined in rainbow trout subjected to chronic confinement stress for 14 days. Confinement significantly elevated plasma cortisol levels to 47.3 ± 13.5 ng ml^–1 within 24h and although levels declined to 8.0 ± 3.0 ng ml^–1 after 14 days, they were significantly higher throughout than levels in unstressed control fish (< 2.0 ng ml^–1). There was a 60% reduction in cytosolic N_max in stressed fish during the first 24h of confinement (35.8 ± 7.9 cf. 129.0 ± 15.2 fmol mg^–1 protein), a decline which was sustained at 7 days after the onset of stress but, although numbers of binding sites in the liver of stressed fish were still lower than in unstressed fish, the difference was no longer significant after 14 days of confinement. There was an accompanying significant rise in the K_d of cortisol binding in stressed fish during confinement, from 4.0 ± 0.6 nM at time 0 to 8.4 ± 0.8 nM after 24 h confinement. This increment in K_d was sustained at a level significantly higher than in control fish throughout the 14 day confinement period, despite marked reductions in cortisol levels and increases in N_max in stressed fish. Throughout the study, specific binding of cortisol could not be consistently detected in high-salt nuclear extracts from stressed or unstressed fish, suggesting either that high-affinity binding sites for cortisol were absent from these preparations, that receptors were present but unable to interact with ligand because they were occupied, or that receptors were present but not being extracted. These possibilities were investigated using a range of extraction procedures, by varying the temperature of incubation, by employing dexamethasone as ligand and by examining binding in purified, intact, nuclei. Estradiol was employed as a methodological control throughout and substantial amounts of specific estradiol binding were detected in all compartments and preparations. Specific cortisol-binding sites were detected in intact nuclei of both stressed and unstressed fish, at levels an order of magnitude lower than estradiol binding in the same preparations. These data demonstrate that activation of the pituitary-interrenal axis leads to significant changes in the nature of target-tissue binding of cortisol in rainbow trout, and reveal a clear difference in the subcellular distribution of binding-sites for estradiol and cortisol, which reflects the situation in mammalian tissues.  相似文献   

Low compliance with recommendations on folic acid use in relation to pregnancy: is there a need for fortification?     

Knudsen VK  Orozova-Bekkevold I  Rasmussen LB  Mikkelsen TB  Michaelsen KF  Olsen SF 《Public health nutrition》2004,7(7):843-850

OBJECTIVE: As a means to prevent neural tube defects (NTDs), women planning pregnancy in Denmark are recommended to take a dietary supplement of 400 microg folic acid daily during the periconceptional period. We examined compliance with this recommendation in a national survey. DESIGN: Cohort study on pregnant women in Denmark. SETTING: The Danish National Birth Cohort (DNBC). SUBJECTS: From November 2000 to February 2002, 22,000 pregnant women were recruited for DNBC. Use of dietary supplements was recorded at enrollment. Compliance with the recommendation was related to an information campaign that took place during the second half of 2001, and to lifestyle factors provided in a telephone interview by the end of the first trimester of pregnancy. RESULTS: An increase was seen in the proportion of women complying with the recommendation in the study period and this coincided with the information campaign events. However, even at the end of the period, only 22.3% of the women who had planned their pregnancy fully complied with the recommendation. No increase at all was seen in periconceptional folic acid use among women with unplanned pregnancies. Young age, low education and smoking were identified as factors that determined non-compliance. CONCLUSIONS: Alternative and more effective strategies are needed if the Danish population is to benefit fully from the knowledge that folic acid prevents NTDs. Future strategies should not only target vulnerable groups, such as the less educated and the young, but also women who get pregnant without planning this. The only possible way to reach the last group may be through fortification of foods with folic acid.  相似文献   

Prevalence and Heritability of Symptomatic Syringomyelia in Cavalier King Charles Spaniels and Long‐term Outcome in Symptomatic and Asymptomatic Littermates          下载免费PDF全文

M.S. Thfner  C.L. Stougaard  U. Westrup  A.A. Madry  C.S. Knudsen  H. Berg  C.S.E. Jensen  R.M.L. Handby  H. Gredal  M. Fredholm  M. Berendt 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(1):243-250

Background

Syringomyelia (SM) is common in the Cavalier King Charles Spaniel (CKCS). Dogs with syringes express clinical signs or might be clinically silent.

Objectives

To investigate the prevalence and heritability of symptomatic SM, the association between clinical signs and magnetic resonance imaging (MRI) findings, and long‐term outcome.

Animals

All CKCS registered in the Danish Kennel Club in 2001 (n = 240).

Methods

A cross‐sectional questionnaire‐based prevalence study validated by telephone interviews and clinically investigated clinical signs of SM. Dogs were 6 years at the time of investigation. A prospective observational litter study including clinical investigations, MRI and 5‐year follow‐up of symptomatic and asymptomatic siblings. Heritability was estimated based on the scale of liability in the study population and litter cohort.

Results

The cross‐sectional study estimated a prevalence of symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9 asymptomatic siblings participated in the litter study. Spinal cord syringes were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean syrinx : spinal cord ratio were significantly correlated with clinical signs (P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM motivated euthanasia in 20%. Dogs with syringes, which expressed no clinical signs at the age of 6, remained asymptomatic in 14/15 cases (93%).

Conclusions and Clinical Importance

The prevalence of symptomatic SM is high and genetics have a high impact on clinical disease expression. Further investigations of factors influencing the outbreak threshold of clinical signs of SM are desirable.  相似文献