Progressive Juvenile Glomerulonephropathy in 16 Related French Mastiff (Bordeaux) Dogs

Background: Familial juvenile glomerulonephropathy (JGN) is reported in several breeds of dogs. The mode of inheritance and spectrum of pathological lesions vary among breeds. A progressive JGN was detected in a pedigree of French Mastiff (FM) dogs. Objectives: To describe clinical, laboratory, and histopathologic findings in related FM dogs suffering from progressive JGN and to determine the mode of inheritance of this condition. Animals: Sixteen affected and 35 healthy related FM dogs Methods: FM dogs <24 months of age and diagnosed with chronic kidney disease with evidence of proteinuria entered the study. Clinical, laboratory, histopathologic findings, and pedigree data were recorded. Results: Clinical signs were typical of progressive glomerulopathy with resultant renal failure. Increased blood urea nitrogen, creatinine and total cholesterol concentrations, and proteinuria were found in all patients. Affected dogs had abnormal kidney structure on abdominal ultrasound examination. Histopathologic examination revealed extensive cystic glomerular atrophy, glomerular hypercellularity, and capillary wall thickening without immune complex deposition when tested with immunohistochemistry or immunofluorescence. Electron microscopy did not disclose specific primary glomerular lesions. Mean age at death was 20 months and mean length of survival after diagnosis was 6 months. Both males and females from healthy parents were affected. An autosomal recessive mode of transmission is suspected, but a more complex mode of inheritance cannot be excluded. Conclusions and Clinical Importance: Progressive familial JGN occurs in FM dogs. Characterization of the pathogenesis and mode of inheritance of this disease warrants additional study.     

The free-water pond under a trickle source: A field test of existing theories

  The size of the free-water ponds under drippers is an important field characteristic of trickle irrigation. Here we review four existing analytical theories that purport to describe 3-D infiltration. We show how they can be used to predict the extent of the pond from basic soil parameters, and the dripper discharge rate. Via a numerical example it is shown that the different theories give significantly different free-water pond radii, especially for high drip discharge rates when the flow is dominated by gravity. We then describe field experiments that were carried out to permit a comparison of the measured and predicted values using independently-measured soil parameters. This test of the different theories was conducted on a loamy soil. Raats' (1971) solution gave the best estimates of the free-water pond radius, across the range of discharge rates. The free-water pond radius, a determinant of the lateral spread away from the dripper, was found to vary only weakly with drip discharge in the range of practical applications. Consequences for management are discussed. Received: 24 September 1995     

Genome sequence of a polydnavirus: insights into symbiotic virus evolution

Little is known of the fate of viruses involved in long-term obligatory associations with eukaryotes. For example, many species of parasitoid wasps have symbiotic viruses to manipulate host defenses and to allow development of parasitoid larvae. The complete nucleotide sequence of the DNA enclosed in the virus particles injected by a parasitoid wasp revealed a complex organization, resembling a eukaryote genomic region more than a viral genome. Although endocellular symbiont genomes have undergone a dramatic loss of genes, the evolution of symbiotic viruses appears to be characterized by extensive duplication of virulence genes coding for truncated versions of cellular proteins.     

A sequence in M13 phage detects hypervariable minisatellites in human and animal DNA

The term "DNA fingerprint" has been used to describe the extensive restriction fragment length polymorphism associated with hypervariable minisatellites present in the human genome. Until now, it was necessary to hybridize Southern blots to specific probes cloned from human genomic DNA in order to obtain individual-specific restriction patterns. The present study describes the surprising finding that the insert-free, wild-type M13 bacteriophage detects hypervariable minisatellites in human and in animal DNA, provided no competitor DNA is used during hybridization. The effective sequence in M13 was traced to two clusters of 15-base pair repeats within the protein III gene of the bacteriophage. This unexpected use of M13 renders the DNA fingerprinting technology more readily available to molecular biology laboratories.     

Temperature sex reversal implies sex gene dosage in a reptile

Sex in reptiles is determined by genes on sex chromosomes or by incubation temperature. Previously these two modes were thought to be distinct, yet we show that high incubation temperatures reverse genotypic males (ZZ) to phenotypic females in a lizard with ZZ and ZW sex chromosomes. Thus, the W chromosome is not necessary for female differentiation. Sex determination is probably via a dosage-sensitive male-determining gene on the Z chromosome that is inactivated by extreme temperatures. Our data invite a novel hypothesis for the evolution of temperature-dependent sex determination (TSD) and suggest that sex chromosomes may exist in many TSD reptiles.     

Expert judgement in a risk assessment model for Salmonella spp. in pork: The performance of different weighting schemes

A structured expert judgement study was carried out in order to obtain input parameters for a quantitative microbial risk assessment (QMRA) model. This model aimed to estimate the risk of human Salmonella infections associated with the consumption of minced pork meat. Judgements of 11 experts were used to derive subjective probability density functions (PDFs) to quantify the uncertainty on the model input parameters.The performance of experts as probability assessors was measured by the experts’ ability to correctly and precisely provide estimates for a set of seed variables (=variables from the experts’ area of expertise for which the true values were known to the analyst). Subsequently different weighting schemes or “decision makers” (DMs) were applied using Cooke's classical model in order to obtain combined PDFs as a weighted linear combination of the expert's individual PDFs.The aim of this study was to compare the performance of four DMs namely the equal weight DM (each expert's opinion received equal weight), the user weight DM (weights are determined by the expert's self-perceived level of expertise) and two performance-based DMs: the global weight DM and the item weight DM. Weights in the performance-based DMs were calculated based on the expert's calibration and information performance as measured on the set of seed variables.The item weight DM obtained the highest performance with a calibration score of 0.62 and an information score of 0.52, as compared to the other DMs. The weights of the performance-based DMs outperformed those of the best expert in the panel. The correlation between the scores for self-rating of expertise and the weights based on the experts’ performance on the calibration variables was low and not significant (r = 0.37, p = 0.13).The applied classical model provided a rational basis to use the combined distributions obtained by the item weight DM as input in the QMRA model since this DM yielded generally more informative distributions for the variables of interest than those obtained by the equal weight and user weight DM. Attention should be paid to find adequate and relevant seed variables, since this is important for the validation of the results of the weighting scheme.     

Interactions between genes involved in growth and muscularity in pigs: IGF-2, myostatin, ryanodine receptor 1, and melanocortin-4 receptor

In the swine breeding industry, two economical traits are of particular importance in sires, namely, muscle growth and average daily gain (ADG). These traits are quantitative, which implies that they are under the control of multiple genes. Mutations in these genes, associated with either muscularity or growth, are useful quantitative trait nucleotides (QTN) for unraveling genetic variation of these traits and can be used in marker-assisted selection. Until now, QTN involved in muscle growth and/or ADG in pigs were identified in porcine ryanodine receptor 1 (RYR1), insulin-like growth factor-2 (IGF-2), and melanocortin-4 receptor (MC4R). Recently, a fourth possible QTN was found in porcine myostatin (MSTN). All four QTN have an influence on muscle growth and/or somatic growth, so an influence of one mutation on one or more of the other mutations should not be excluded. However, although the polymorphisms in the RYR1 and the MC4R gene affect the function of the respective protein, the polymorphisms of the IGF-2 and MSTN gene influence the mRNA expression of the respective gene. Therefore, this study investigated possible interactions between the genotypes of MSTN, IGF-2, and MC4R (population 1) or the RYR1, IGF-2, and MSTN QTN (population 2) on IGF-2 and MSTN expression in different muscle types in pigs. In both skeletal muscle and heart muscle growth, the IGF-2:MSTN ratio seems to play an important role. Also, the RYR1 genotype had a significant effect on IGF-2 expression in m. longissimus dorsi. No effect of the MC4R QTN could be seen.     

Development and comparison of four real-time polymerase chain reaction systems for specific detection and quantification of Zea mays L

Four real-time polymerase chain reaction systems aiming at the specific detection and quantification of maize DNA are described. They have been developed in four independent laboratories targeting different maize sequences, i.e., alcohol dehydrogenase (Adh1), high mobility group protein (hmga), invertase A (ivr1), and zein, respectively. They were all fully specific, showing a very similar quantification accuracy along a number of distantly related maize cultivars and being either single or low copy number genes. They were highly sensitive and exhibited limits of quantification below 100 maize genomic copies. In consequence, they are considered suitable for use as maize specific endogenous reference genes in DNA analyses, including GMO quantitative tests.