Evaluation of von Willebrand Factor During Pregnancy,Lactation and Oestrous Cycle in Bitches Affected and Unaffected by von Willebrand Disease

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF levels and cortisol levels in both groups. Seven vWD affected (GI) and nine unaffected (GII) bitches were used. The animals were assessed during pregnancy, parturition, lactation and non‐gestational oestrous cycle in 11 moments (Pregnancy 1, Pregnancy 2, Parturition, Lactation 1, Lactation 2, Lactation 3, Anestrus, Proestrus, Oestrus, Diestrus 1, and Diestrus 2). The following tests were performed; measurement of von Willebrand factor antigen (vWF:Ag), albumin and cortisol. In both groups, vWF concentration remained stable during the non‐gestational oestrous cycle, but increased during pregnancy, with the highest value observed at parturition. Increases of 70% and 124% in vWF were seen in GI and GII, respectively, compared to anestrus. No correlation was found between vWF and cortisol. Values of vWF:Ag changed during pregnancy, with a peak at parturition, both in vWD affected and unaffected animals. Values of vWF were not altered in the different phases of the oestrous cycle following pregnancy in both groups. Evaluation of vWF during pregnancy can cause false negative results for vWD, but assessment can be performed at any point in the oestrous cycle of non‐pregnant bitches.     

Production of the bioactive compound eritadenine by submerged cultivation of shiitake (Lentinus edodes) mycelia

Fruit bodies and mycelia of shiitake mushroom ( Lentinus edodes) have been shown to contain the cholesterol-reducing compound eritadenine, 2( R),3( R)-dihydroxy-4-(9-adenyl)butyric acid. In the search for a production method for eritadenine, shiitake mycelia were investigated in the present study. The mycelia were cultivated both in shake flasks and in bioreactors, to investigate the effects of pH, stirring rate, and reactor type on the production and distribution of eritadenine. Both the biomass and the culture broth were examined for their eritadenine content. In the shake flasks, the final concentration of eritadenine was 1.76 mg/L and eritadenine was equally distributed between the mycelia and the growth media. In the bioreactors, the shiitake mycelia were found to contain eritadenine in relatively low levels, whereas the majority, 90.6-98.9%, was detected in the growth media. Applying a stirring rate of 250 rpm during bioreactor cultivation resulted in the highest eritadenine concentrations: 10.23 mg/L when the pH was uncontrolled and 9.59 mg/L when the pH was controlled at 5.7. Reducing the stirring rate to 50 rpm resulted in a decreased eritadenine concentration, both at pH 5.7 (5.25 mg/L) and when pH was not controlled (5.50 mg/L). The mycelia in the shake flask cultures appeared as macroscopic aggregates, whereas mycelia cultivated in bioreactors grew more as freely dispersed filaments. This study demonstrates for the first time the extra- and intracellular distribution of eritadenine produced by shiitake mycelial culture and the influence of reactor conditions on the mycelial morphology and eritadenine concentrations.     

Can Graphical Vector Analysis be Used to Identify Micro Nutrient Deficiency?

Initial analysis of needle nutrient status and visible symptoms suggested that a declining Norway spruce (Picea abies L. Karst.) stand in south Sweden was suffering from B and Cu deficiency. Effects of addition of 1000 kg ha^-1 of a commercial N-free fertilizer containing macro nutrients plus B, Cu, and Zn were investigated. B concentrations and B/N ratios were increased significantly in needles from fertilized trees compared to the control, to levels well above critical levels of deficiency and optimum nutrient ratios. In contrast, the treatment did not change the low needle Cu status and there was no effect on growth measured as needle mass after one growing season. Graphical vector analysis together with the absence of change in needle mass suggested a luxury uptake of B. Application of the concepts for critical levels of deficiency and optimum nutrient ratios in relation to N suggested B and Cu deficiency were contributing factors to the observed forest damage in the area. Graphical vector analysis requires a rapid response in needle mass, in combination with improved needle nutrient status in order to identify nutrient deficiencies. The applicability of the technique appears to be limited to primarily growth-promoting nutrients.     

Sample pooling for real-time PCR detection and virulence determination of the footrot pathogen <Emphasis Type="Italic">Dichelobacter nodosus</Emphasis>

Dichelobacter nodosus is the principal cause of ovine footrot and strain virulence is an important factor in disease severity. Therefore, detection and virulence determination of D. nodosus is important for proper diagnosis of the disease. Today this is possible by real-time PCR analysis. Analysis of large numbers of samples is costly and laborious; therefore, pooling of individual samples is common in surveillance programs. However, pooling can reduce the sensitivity of the method. The aim of this study was to develop a pooling method for real-time PCR analysis that would allow sensitive detection and simultaneous virulence determination of D. nodosus. A total of 225 sheep from 17 flocks were sampled using ESwabs within the Swedish Footrot Control Program in 2014. Samples were first analysed individually and then in pools of five by real-time PCR assays targeting the 16S rRNA and aprV2/B2 genes of D. nodosus. Each pool consisted of four negative and one positive D. nodosus samples with varying amounts of the bacterium. In the individual analysis, 61 (27.1%) samples were positive in the 16S rRNA and the aprV2/B2 PCR assays and 164 (72.9%) samples were negative. All samples positive in the aprV2/B2 PCR-assay were of aprB2 variant. The pooled analysis showed that all 41 pools were also positive for D. nodosus 16S rRNA and the aprB2 variant. The diagnostic sensitivity for pooled and individual samples was therefore similar. Our method includes concentration of the bacteria before DNA-extraction. This may account for the maintenance of diagnostic sensitivity. Diagnostic sensitivity in the real-time PCR assays of the pooled samples were comparable to the sensitivity obtained for individually analysed samples. Even sub-clinical infections were able to be detected in the pooled PCR samples which is important for control of the disease. This method may therefore be implemented in footrot control programs where it can replace analysis of individual samples.     

Use of a monoclonal antibody against envelope protein gp51 of bovine leukemia virus in a test for the diagnosis of enzootic bovine leukosis

A highly specific monoclonal antibody (mAb) directed against envelope protein gp51 and effectively bonding the antigen (Ag) on account of its high affinity from an unpurified Ag preparation was chosen for use in a double-sandwich enzyme immuno-assay (EIA) for diagnosis of bovine leukaemia virus (BLV). The epitopes recognised in bovine sera by the gp51-specific antibodies were at the same time properly exposed. Some parameters of major importance to testing were optimised (Ab and Ag quantities, dilution of bovine sera for testing). Preliminary testing of the double-sandwich EIA on selected bovine sera and comparison with both the immunodiffusion test and anti-BLV EIA confirmed its good diagnostic specificity and sensitivity. Hence, this double-sandwich EIA, developed by means of an mAB against gp51, on account of the possibility to use as Ag culture supernatant of the FLC cell line, is a sensitive, low-cost alternative to the anti-BLV EIA Dessau MTP which had so far been used. The double-sandwich EIA is recommended for use in final sanitation for its high analytical and diagnostic sensitivity.     

Intracloacal Salmonella typhimurium infection of broiler chickens: reduction of colonization with anaerobic organisms and dietary lactose

The combined effect of treatments with dietary lactose plus anaerobic organisms on cecal colonization of broiler chicks by Salmonella typhimurium was evaluated. Chickens treated with a combination of anaerobic organisms and 7% dietary lactose were resistant to cecal colonization by S. typhimurium. The number of recoverable S. typhimurium cells per gram of cecal contents taken on days 10 and 15 after infection was significantly reduced. Treatment with anaerobes without the addition of lactose did not effectively control cecal colonization. Intracloacal inoculations with bacterial concentrations that varied by 10,000-fold resulted in roughly similar levels of colonization. The treatments resulted in reduced cecal pH and elevated levels of undissociated volatile fatty acids. Statistically significant correlations (P less than 0.01) were observed between the S. typhimurium concentrations in cecal material and the concentrations of undissociated fatty acids (r = -0.79, and between the bacterial counts and pH (r = 0.72).     

Estimating landscape resistance from habitat suitability: effects of data source and nonlinearities

Context

Conservation corridors must facilitate long-distance dispersal movements to promote gene flow, prevent inbreeding, and allow animals to shift ranges with climate change. Least-cost models are used to identify areas that support long-distance movement. These models rely on estimates of landscape resistance, which are typically derived from habitat suitability.

Objectives

We examine two key steps in estimating resistance from habitat suitability: choosing a procedure to estimate habitat suitability, and choosing a transformation function to translate habitat suitability into resistance.

Methods

We used linear and nonlinear functions to convert three types of habitat suitability estimates (from expert opinion, resource selection functions, and step selection functions) into resistances for elk (Cervus canadensis) and desert bighorn sheep (Ovis canadensis nelsoni). We evaluated the resulting resistance maps on an independent set of observed long-distance, prospecting movements.

Results

A negative exponential function best described the relationship between resistance values and habitat suitability for desert bighorn sheep indicating long-distance movers readily travel through moderately-suitable areas and avoid only the least suitable habitat. For desert bighorn sheep, all three suitability estimates performed better than chance, and resource and step selection functions outperformed expert opinion. For elk, all three suitability estimates performed the same as chance.

Conclusions

When designing corridors to facilitate long-distance movements of mobile animals, we recommend transforming habitat suitability into resistance with a negative exponential function. Use of an exponential transformation means that larger fractions of the landscape offer low resistance, allowing greater flexibility in where a corridor is located.