91 research outputs found
Selection for large and small litter size of the first three litters in mice
International audienc
SĂ©lection sur la vitesse de croissance post-sevrage chez le lapin
On a effectuĂ© une expĂ©rience de sĂ©lection massale sur la vitesse de croissance entre le sevrage (30 j) et 77 j dans une souche de lapin. La souche sĂ©lectionnĂ©e se composait de 12 mĂąles et 60 femelles pendant les 4 premiĂšres gĂ©nĂ©rations puis de 8 mĂąles et 40 femelles pendant les 4 suivantes. La souche tĂ©moin se composait aussi de 8 mĂąles et de 40 femelles. On a rĂ©alisĂ© une intensitĂ© de sĂ©lection de 0,95. La vitesse de croissance post-sevrage est amĂ©liorĂ©e de 6,9 g pour 8 gĂ©nĂ©rations, soit un progrĂšs de 0,83 g par gĂ©nĂ©ration. LâhĂ©ritabilitĂ© rĂ©alisĂ©e est Ă©gale Ă 0,23. Pour une augmentation dâun g de la vitesse de croissance post-sevrage, on observe une diminution de 0,10 du nombre de lapins vivants Ă la naissance par portĂ©e. SimultanĂ©ment, le nombre de lapins vivants Ă 77 j produits par femelle mise Ă la reproduction a tendance Ă diminuer. Cette rĂ©duction de la fitness est due principalement Ă une diminution du nombre de femelles ayant fait au moins une portĂ©e avec un lapin vivant Ă 77 j.A selection experiment was made on the growth rate between weaning (30 days) and 77 days in a rabbit strain. There were 12 bucks and 60 does in the selected strain during the first4 generations, then 8 bucks and l,0 does during the next 4 generations. There were 8 bucks and 40 does in the control strain. Selection intensity was 0.95. The response in post-weaning growth rate was 6.9 g after 8 generations, i.e. 0.83 g per generation. The realized heritability was 0.23. The increase in post-weaning growth rate was accompanied b an increase in 77-days body weight (58 g) and by a decrease in litter size at birth (-0.10) At the same time, the number of rabbits alive at 77 days per reproductive doe decreased. The main reason for the decrease of fitness was a decrease in the number of does with at least one rabbit alive at 77 days
Calculation of the efficacy of vaccines against tick infestations on cattle
Articles in International JournalsCattle ticks are responsible for great economic losses in cattle farming worldwide, and their main control method,
chemicals, has been showing problems, whether resulting from the development of resistant strains of ticks or
environmental contamination. Research studies directed toward developing vaccines against ticks are emerging. One
way to evaluate those vaccines is to calculate the percentage of efficacy. The aim of this study was to analyze scientific
publications archived in PubMed that used this method of assessment and discuss the main factors that may affect its
calculation. Thus, 25 articles addressing this subject were selected. The percentage of efficacy was usually calculated
in one of two ways, with one considering the reduced fertility of eggs and the other not. The latter method may
underestimate the vaccine efficacy, and the most complete formula for calculating the efficacy reflects how much the
vaccine actually affects the infestation. In our view, the use of the complete formula for calculating the percentage of
efficacy is broader and more representative of the vaccine effect on the tick population.RESUMO - Carrapatos de bovinos sĂŁo responsĂĄveis por grandes perdas econĂŽmicas para a pecuĂĄria bovina mundial e seu principal
mĂ©todo de controle, o quĂmico, vem apresentando problemas, seja pelo desenvolvimento de amostras de carrapatos
resistentes ou pela contaminação ambiental. Na tentativa de diminuir a utilização dos acaricidas, surgem pesquisas
direcionadas ao desenvolvimento de vacinas contra carrapatos. Uma maneira de avaliar essas vacinas Ă© pelo cĂĄlculo de
percentagem de eficĂĄcia. O objetivo deste trabalho foi analisar as publicaçÔes cientĂficas indexadas no PubMed que
utilizaram este método de avaliação e discutir os principais fatores que podem interferir no seu cålculo. Dessa maneira,
selecionaram-se 25 artigos que tratavam desse assunto. A percentagem de eficĂĄcia apareceu sendo calculada de duas
formas, uma considerando a redução da fertilidade dos ovos e a outra nĂŁo. Essa Ășltima pode subestimar a eficiĂȘncia da
vacina, e a fórmula de cålculo da eficåcia mais completa representa o quanto da infestação a vacina realmente reduziu.
Em nosso entendimento, a utilização da fórmula completa para o cålculo da percentagem de eficåcia é mais abrangente
e representativa do efeito da vacina na população de carrapatos
A Differential Network Approach to Exploring Differences between Biological States: An Application to Prediabetes
Background: Variations in the pattern of molecular associations are observed during disease development. The comprehensive analysis of molecular association patterns and their changes in relation to different physiological conditions can yield insight into the biological basis of disease-specific phenotype variation. Methodology: Here, we introduce a formal statistical method for the differential analysis of molecular associations via network representation. We illustrate our approach with extensive data on lipoprotein subclasses measured by NMR spectroscopy in 4,406 individuals with normal fasting glucose, and 531 subjects with impaired fasting glucose (prediabetes). We estimate the pair-wise association between measures using shrinkage estimates of partial correlations and build the differential network based on this measure of association. We explore the topological properties of the inferred network to gain insight into important metabolic differences between individuals with normal fasting glucose and prediabetes. Conclusions/Significance: Differential networks provide new insights characterizing differences in biological states. Based on conventional statistical methods, few differences in concentration levels of lipoprotein subclasses were found between individuals with normal fasting glucose and individuals with prediabetes. By performing the differential analysis of networks, several characteristic changes in lipoprotein metabolism known to be related to diabetic dyslipidemias were identified. The results demonstrate the applicability of the new approach to identify key molecular changes inaccessible to standard approaches
Transmission-Blocking Vaccines: Focus on Anti-Vector Vaccines against Tick-Borne Diseases
Tick-borne diseases are a potential threat that account for significant morbidity and mortality in human population worldwide. Vaccines are not available to treat several of the tick-borne diseases. With the emergence and resurgence of several tick-borne diseases, emphasis on the development of transmission-blocking vaccines remains increasing. In this review, we provide a snap shot on some of the potential candidates for the development of anti-vector vaccines (a form of transmission-blocking vaccines) against wide range of hard and soft ticks that include Ixodes, Haemaphysalis, Dermacentor, Amblyomma, Rhipicephalus and Ornithodoros species
Deregulation upon DNA damage revealed by joint analysis of context-specific perturbation data
<p>Abstract</p> <p>Background</p> <p>Deregulation between two different cell populations manifests itself in changing gene expression patterns and changing regulatory interactions. Accumulating knowledge about biological networks creates an opportunity to study these changes in their cellular context.</p> <p>Results</p> <p>We analyze re-wiring of regulatory networks based on cell population-specific perturbation data and knowledge about signaling pathways and their target genes. We quantify deregulation by merging regulatory signal from the two cell populations into one score. This joint approach, called JODA, proves advantageous over separate analysis of the cell populations and analysis without incorporation of knowledge. JODA is implemented and freely available in a Bioconductor package 'joda'.</p> <p>Conclusions</p> <p>Using JODA, we show wide-spread re-wiring of gene regulatory networks upon neocarzinostatin-induced DNA damage in Human cells. We recover 645 deregulated genes in thirteen functional clusters performing the rich program of response to damage. We find that the clusters contain many previously characterized neocarzinostatin target genes. We investigate connectivity between those genes, explaining their cooperation in performing the common functions. We review genes with the most extreme deregulation scores, reporting their involvement in response to DNA damage. Finally, we investigate the indirect impact of the ATM pathway on the deregulated genes, and build a hypothetical hierarchy of direct regulation. These results prove that JODA is a step forward to a systems level, mechanistic understanding of changes in gene regulation between different cell populations.</p
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