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At least 145 records · Page 8Linked to original sources
PubMed2006

[Expression and localization of the cellular prion protein (PrPc) in the cow's central nervous system. Some reflections on the nvCJD].

INTRODUCTION: The appearance of bovine spongiform encephalopathy (BSE) and its involvement in the generation of the new variant of Creutzfeldt-Jakob Disease (nvCJD) had important implications from a social and economical point of view. As the presence of PrPC is necessary to establish prion diseases and for the replication of PrPSC in BSE, the study of the expression and localization of PrPC in the central nervous system of cow, mainly the brainstem, is interesting itself. MATERIAL AND METHODS: Expression of PrP by western blot technique and its precise localization by immunohistochemistry were analyzed in the central nervous system of the autochthonous pyrenees breed, a group of cows with a high incidence for BSE. RESULTS: PrP was more abundantly expressed in rostral areas rather than caudal regions of the cow brain. Immunohistochemistry was congruent with western blotting studies. Localization of PrPC was particularly abundant in the cerebral cortex, hippocampus, etc. Noteworthy, immunopositivity was present in the dorsal motor nucleus of the vagus and the hypoglossal nucleus. The anterior horn of the spinal cord yielded higher labelling for PrP than the posterior horn. CONCLUSION: PrPC is more abundantly expressed in rostral areas of the central nervous system. According to the findings observed in other mammal species, presence of PrPC in motoneurons of cow indicates that PrPSc might be transported from its site of entry to the central nervous system following a retrograde direction.

Animals↗
PubMed1997

Are animal models of diabetes relevant to the study of the genetics of non-insulin-dependent diabetes in humans?

Although it is well-recognized that non-insulin-dependent diabetes-mellitus (NIDDM) shown a strong genetic component the search for candidate genes has been very difficult since NIDDM is a complex, heterogeneous, multifactorial syndrome resulting from both genetic susceptibility and environmental risk factors. Therefore, the use of inbred animal models is an essential component of genetic investigations in this field. As these lines are genetically homogeneous, it is possible to direct mating for optimal genetic crosses and control environmental factors. Strains with spontaneous NIDDM may be constituted from animals with one or several genetic mutation(s) transmitted generation to generation or selected from non-diabetic outbred animals by repeated breeding. The ob/ob and db/db mice, which are rodent models of NIDDM and obesity, belong to the first category. Recent studies using the positional cloning approach allowed the mapping of ob gene and identification of its product, leptin, which is a protein secreted by white adipose tissue and involved in the control of food intake. The db gene encodes the leptin receptor. The search for genetic linkage was undertaken in polygenic models, especially the Goto-Kakisaki (GK) rat which was obtained by selective breeding of individuals with glucose intolerance from a non-diabetic Wistar rat colony. Though precise definition of sub-phenotypes of glucose tolerance and insulin secretion, the mapping of microsatellite markers and QTL analysis, it has proved possible to identify many independent loci containing genes regulating glucose homeostasis and insulin secretion. In another polygenic model, the OLETF rat, a locus present on chromosome X was identified. Many complementary approaches in different strains may lead to the identification of candidate genes for NIDDM and help direct the search for candidate genes in humans who show synteny relationships with rodents.

Animals↗
PubMed2006

Marker-based prediction of the parental genome contribution to inbred lines derived from biparental crosses.

Molecular markers can be employed to predict the parental genome contribution to inbred lines. The proportion alpha of alleles originating from parent P1 at markers polymorphic between the parental lines P1 and P2 is commonly used as a predictor for the genome contribution of parent P1 to an offspring line. Our objectives were to develop a new marker-based predictor xi for the parental genome contribution, which takes into account not only the alleles at marker loci but also their map distance, and to compare the prediction precision of xi with that of alternative methods. We derived formulas for xi for inbreds derived from biparental crosses (F1 and backcrosses) with the single-seed descent or double-haploid method and presented an extension xi* possessing statistical optimum properties. In a simulation study, alpha showed a systematic overestimation of large parental genome contribution that was not observed for xi. The mean squared prediction error of xi was at least 50% smaller than that of alpha for linkage maps with unequal distances between adjacent markers. A data set from a study on plant variety protection in maize was used to illustrate the application of xi. We conclude that xi provides substantially greater prediction precision than the commonly used predictor alpha in a broad range of applications in genetics and breeding.

Computer Simulation↗
PubMed2001

Polymorphism maintenance in populations with mixed random mating and apomixis subjected to stabilizing and cyclical selection.

We analysed a diploid population model with a mixed breeding system that includes panmixia and apomixis. Each individual produces a part (ss) of its progeny by random mating, the remainder (1-ss) being a result of precise copying (vegetative reproduction or apomixis) of the parental genotype. Both constant and periodically varying selection regimes were considered. In the main model, the selected trait was controlled by two diallelic additive or semidominant loci, A/a and B/b, whereas the parameter of breeding system (ss) was genotype-independent. A numerical iteration of the evolutionary equations were used to evaluate the proportion (V) of population trajectories converging to internal (polymorphic) fixed points. The results were the following. (a) A complex pattern of dependence of polymorphism stability on interaction among the breeding system, recombination rate, and the genetic architecture of the selected trait emerged. (b) The recombination provided some advantage to sex at intermediate period lengths and strong-to-moderate selection intensities. (c) The complex limiting behavior (CLB) was quite compatible with sexual reproduction, at least within the framework of pure genetic (not including variations in population density) models of multilocus varying selection.

Animals↗
PubMed1997

A deletion in the bovine myostatin gene causes the double-muscled phenotype in cattle.

An exceptional muscle development commonly referred to as 'double-muscled' (Fig. 1) has been seen in several cattle breeds and has attracted considerable attention from beef producers. Double-muscled animals are characterized by an increase in muscle mass of about 20%, due to general skeletal-muscle hyperplasia-that is, an increase in the number of muscle fibers rather than in their individual diameter. Although the hereditary nature of the double-muscled condition was recognized early on, the precise mode of inheritance has remained controversial; monogenic (domainant and recessive), oligogenic and polygenic models have been proposed. In the Belgian Blue cattle breed (BBCB), segregation analysis performed both in experimental crosses and in the outbred population suggested an autosomal recessive inheritance. This was confirmed when the muscular hypertrophy (mh) locus was mapped 3.1 cM from microsatellite TGLA44 on the centromeric end of bovine chromosome 2 (ref. 5). We used a positional candidate approach to demonstrate that a mutation in bovine MSTN, which encodes myostatin, a member of the TGF beta superfamily, is responsible for the double-muscled phenotype. We report an 11-bp deletion in the coding sequence for the bioactive carboxy-terminal domain of the protein causing the muscular hypertrophy observed in Belgian Blue cattle.

Amino Acid Sequence↗
PubMedDate not supplied

[Joint research on the precise determination of the energy and protein requirements of fattening pigs. 10. Comparative evaluation of the research for the precise determination of the energy and protein requirements of fattening pigs].

Institutes from 5 CMEA countries took part in complementary joint investigations in order to ascertain the variance in energy and protein requirement and parameters of nutrient and energy metabolism with such fattening pigs as test animals as characterise the prospective breeding development in each of the countries and in order to establish the bases for the critical revision of the norms of energy and protein requirement for fattening pigs and, if necessary, their more precise determination. The most important conclusion drawn from the comparative assessment of the results presented in 9 articles is that due to wide variations in the energy and protein requirement values between the individual investigators as well as within the institutions themselves, norms of energy and protein requirement for fattening can only be adopted between countries when adequate investigations under the specific conditions of the individual countries justify this.

Animal Nutritional Physiological Phenomena↗
PubMed1975

Adaptive significance of synchronized breeding in a colonial bird: a new hypothesis.

Bank swallows nest gregariously in colonies usually ranging from 10 to 300 nests. Different pairs within the same colony are highly synchronized with each other, and 67 percent of the nests fledged their young over a period of only 6 days. This high degree of synchronization is demonstrated to be of adaptive significance. Reproductive fitness increases as a function of the precision of synchrony of the colony. It is proposed that social foraging plays an important role in maximizing the feeding efficiency in this species and that asynchronous breeding decreases the effectiveness of this social foraging, particularly in late nesters and among young, newly fledged birds. An individual that fledges either early or at the peak of synchrony will emerge to find a steady stream of other bird traveling to local, ephemeral, concentrations of food. The late emerger finds itself practically alone and thus is deprived of the potential benefits of the pooled information about locations of food resources available to the full colony.

Adaptation, Biological↗
PubMed2005

Genomics-assisted breeding for crop improvement.

Genomics research is generating new tools, such as functional molecular markers and informatics, as well as new knowledge about statistics and inheritance phenomena that could increase the efficiency and precision of crop improvement. In particular, the elucidation of the fundamental mechanisms of heterosis and epigenetics, and their manipulation, has great potential. Eventually, knowledge of the relative values of alleles at all loci segregating in a population could allow the breeder to design a genotype in silico and to practice whole genome selection. High costs currently limit the implementation of genomics-assisted crop improvement, particularly for inbreeding and/or minor crops. Nevertheless, marker-assisted breeding and selection will gradually evolve into 'genomics-assisted breeding' for crop improvement.

Breeding↗
PubMed1992

Prosthetic restoration of the anterior edentulous space.

The dentition of partially edentulous patients with an anterior modification space may be restored in several ways. If a removable partial denture is selected as the treatment of choice, denture tooth selection, direct retainer display, and anterior-posterior rotation may be sources of concern for the patient and dentist. A way to overcome the treatment problems associated with these partially edentulous patients is use of a Hader bar and clip-retained removable partial denture with the attachment of an anterior porcelain-fused-to-metal facade. This article describes this treatment option and the technique for fabrication.

Dental Abutments↗
PubMed2000

Reproductive management of silver foxes (Vulpes vulpes) in captivity.

Specific protocols need to be developed that take into consideration the requirements of silver foxes. This study was designed to investigate the reproduction of 26 pairs of silver foxes (Vulpes vulpes). Reproduction parameters (breeding season, age at puberty, fecundity and fertility) of the foxes were examined under experimental conditions, and new techniques to optimize fox breeding were assessed. Staining of the vaginal smears with the double Harris-Schorr stain allowed for the precise detection of estrus and proved to be more reliable than simply measuring vaginal resistance. Ultrasonography was demonstrated to be useful for pregnancy diagnosis and prediction of parturition. Results demonstrate that the methods reported in this paper are easily applicable to similar studies carried out on small groups of animals within the framework of fox animal experimentation.

Animals↗
PubMed1999

Technical note: direct genotyping of the double-muscling locus (mh) in Piedmontese and Belgian Blue cattle by fluorescent PCR.

A simple PCR-based allele detection system has been developed to assist in the management of the two most prevalent double-muscled (mh) breeds in the U.S. Application of this assay will permit the implementation of structured mating systems dependent on precise genotypes at the mh locus. The genetic assay uses standard fluorescent genotyping technology and relies on the unique nucleotide composition of wild-type and mutant alleles of myostatin, the gene underlying the double-muscled phenotype. We present data demonstrating the efficacy of this fluorescent primer-based PCR assay in genotyping animal populations carrying normal and(or) mutant alleles of the myostatin gene.

Alleles↗
PubMed2000

[RAPD-analysis of duck genetic polymorphisms. Interlineal differences in a Peking duck species].

The possibility of using RAPD markers for the detection of differences between lines of Peking duck constituting a local population maintained at the Blagovarskii State Farm for Pedigree Poultry was demonstrated. Genetic distances based on the RAPD markers precisely and accurately reflect even small changes that occurred in the genetic structure of Peking duck lines during breeding of parental forms. The pattern of inheritance of RAPD markers obtained using primer HM13 was studied in the F1 progeny of two families. The results can be used for improvement of available high-productivity lines of ducks breeding of new lines, and promotion of the combining abilities of lines.

Animals↗
PubMed1977

[Selective contrast enhancement of microscopical specimen by optical procedures for automatized quantitative image analysis (author's transl)].

One of the most important problems in automatic image analysis is the discrimination of features by, a certain range of grey levels. To obtain as many as possible different grey levels sufficient contrast is achieved mainly by specific staining. Alternative and supplementary methods are some micrscopical methods, not routinely used. Interference microscopy, interference reflexion microscopy and microfluorimetry are discussed in detail. These optical procedures enhance the contrast of specimen specifically without the necessity for the application of specimen specifically without the necessity for the application of sophisticated staining methods. In interference contrast, tissues can be separately detected by grey level discrimination due to varying concentration of dry mass; this is shown for a cornifying part of fish skin (breeding tubercle of Rutilus rutilus L.). Furthermore, very small amounts of dry matter can be determined with high precision, as demonstrated for a single tissue culture cell (XTH-cell). Automatisation of image analysis provides a unique opportunity for routine application of interferometric measurements. The principles of the procedures are outlined. By interference reflexion microscopy cellular attachment areas to a glass surface are visualized, providing a powerful tool in cellular diagnosis based on grey level discrimination (darkest parts correspond to zones of closest contact to the substratum). A fast migrating lymphocyte and stationary endothelial cells have been chosen for demonstration. Various histochemical problems can be solved elegantly by fluorescence methods, e.g. mitochondria in living cells are specifically stained by a fluorochrome (DASPMI) and the distribution of fluorescence intensity can be followed within the mitochondrial population of a cell. Fluorescence was recorded from fotographic negatives taken with a fluorescence microscope. Additionally a short comment is given on the application of polarisation microscopy for feature detection.

Animals↗
PubMedDate not supplied

[Assessing the accuracy of the practice of a method of scoring the body condition of ewes within a professional framework].

The accuracy of the body condition scoring for ewes using lumbar palpation was assessed by mean of an experiment conducted under conditions close to those occurring everyday on the farms. Thirteen operators evaluated the body condition score twice in a sample of 48 Lacaune breed dairy ewes, using a semi-quantitative grid (from 0 to 5 points, with a 0.25 point precision). Under the experimental conditions, the repeatability of the method, i.e. the comparison between the scores given by the same operator to the same animals for the two successive scoring notations, was good and even very good (Kappa test), if a 0.25 point precision is tolerated. On the other hand, the reproducibility, i.e. the comparison between the scores given to the same animals by differents operators was poor. Therefore, this method is easy to master for the management of a given flock by a single person. However in order to make comparisons between flocks, in reference to body condition standards set up for different farming systems, this method needs greater precision. Some of the application conditions required for this are discussed.

Animal Husbandry↗
PubMed1981

Derivation of a breeding colony of germ-free athymic mice by cesarean section and foster nursing.

Germ-free athymic mice were obtained by removing the uterus by cesarean section from a gravid heterozygous (nu/+) female at precisely full term. The uterus was transferred into a germ-free flexible isolator containing two germ-free CD-1 mice that were communally nursing their recently delivered litters. These germ-free CD-1 mice served as foster mothers for the newborn germ-free athymic mice.

Animals↗
PubMed2005

Development of SNP assays for genotyping the puroindoline b gene for grain hardness in wheat using pyrosequencing.

Grain hardness is one of the most important quality characteristics of cultivated bread wheat (Triticum aestivum L.) and has been reported to result from either a failure to express puroindoline a (Pina) or single-nucleotide mutations in puroindoline b (Pinb). Up to now, seven alleles from Pinb-D1a to Pinb-D1g were identified in bread wheat. Compared to the DNA coding region of Pinb-D1a (allele for softness), six single-nucleotide polymorphisms (SNPs) were detected in six alleles for Pinb-D1. In this study, we used pyrosequencing technology to develop two SNP assays for identification of the seven Pinb alleles and characterized SNP variations in the Pinb of 493 European wheat varieties. Of the three hardness alleles Pinb-D1b, Pinb-D1c, and Pinb-D1d detected in this study, Pinb-D1b was the most predominant hardness allele in European hard wheats. The hardness genotypes of partial German wheat varieties available confirmed the reliability and validation of the SNP assays developed for the Pinb locus. Therefore, pyrosequencing technology offers an efficient, precise, and reliable concept for high-throughout genotyping to assist selection of grain hardness genes in wheat quality breeding programs.

Alleles↗
PubMed1992

Identifying genes involved in the variability of genetic fatness in the growing chicken.

A precise knowledge of the genome involved in the expression of a quantitative trait could provide a useful tool in breeding programs; molecular genetic methods are capable of yielding this kind of information. An experimental procedure is presented here for identifying genes whose expression is related to weight variability of abdominal adipose tissue in the growing chicken. Quantitative traits are the result of metabolic pathways exhibiting some major regulation stages that are controlled genetically. These steps involve genes that may act as "major genes". With regard to chicken fat metabolism, most fatty acids are synthesized in the liver and incorporated into very low density lipoprotein (VLDL) particles before their secretion into the plasma. Accordingly, the present study focused on the expression of liver genes. The mRNA of lipogenic enzymes (acetyl-coenzyme-A carboxylase, fatty acid synthase, malic enzyme, and delta 9-desaturase) were analyzed. Also studied were apoprotein (apo)A1, apoVLDL-II, and apoB mRNA from 9-wk-old male chickens from two lines selected for high and low abdominal fat pads. Significant differences for apoA1 mRNA levels occurred between fat and lean birds. Moreover, the total quantity of mRNA provided an accurate estimation of the abdominal fat pad (r = .74 with P < .05).

Adipose Tissue↗
PubMed1997

The beta-amyloid precursor protein of Alzheimer's disease enhances neuron viability and modulates neuronal polarity.

beta-Amyloid precursor protein (betaPP) can reside at neuron and glial cell surfaces or undergo proteolytic processing into secreted fragments. Although betaPP has been studied extensively, its precise physiological role is unknown. A line of transgenic knock-out mice selectively deficient in betaPP survive and breed but exhibit motor dysfunction and brain gliosis, consistent with a physiological role for betaPP in neuron development. To elucidate these functions, we cultured hippocampal neurons from wild-type and betaPP-deficient mice and compared their ability to attach, survive, and develop neurites. We found that hippocampal neurons from betaPP-deficient mice had diminished viability and retarded neurite development. We also compared the effects of betaPP secretory products, released from wild-type astrocytes, on process outgrowth from wild-type and betaPP-deficient hippocampal neurons. Outgrowth was enhanced at 1 d in the presence of wild-type astrocytes, as compared with betaPP-deficient astrocytes. However, by 3 d, neurons had shorter axons but more minor processes with more branching when cocultured with wild-type astrocytes, as compared with betaPP-deficient astrocytes. Our data demonstrate that cell-associated neuronal betaPP contributes to neuron viability, axonogenesis, and arborization and that betaPP secretory products modulate axon growth, dendrite branching, and dendrite numbers.

Alzheimer Disease↗