Совершенствование управления краткосрочными активами предприятия (на примере ОАО «СтанкоГомель»)

Determining which reference genes have the highest stability, and are therefore appropriate for normalising data, is a crucial step in the design of real-time quantitative PCR (qPCR) gene expression studies. This is particularly warranted in non-model and ecologically important species for which appropriate reference genes are lacking, such as the mallard-a key reservoir of many diseases with relevance for human and livestock health. Previous studies assessing gene expression changes as a consequence of infection in mallards have nearly universally used β-actin and/or GAPDH as reference genes without confirming their suitability as normalisers. The use of reference genes at random, without regard for stability of expression across treatment groups, can result in erroneous interpretation of data. Here, eleven putative reference genes for use in gene expression studies of the mallard were evaluated, across six different tissues, using a low pathogenic avian influenza A virus infection model. Tissue type influenced the selection of reference genes, whereby different genes were stable in blood, spleen, lung, gastrointestinal tract and colon. β-actin and GAPDH generally displayed low stability and are therefore inappropriate reference genes in many cases. The use of different algorithms (GeNorm and NormFinder) affected stability rankings, but for both algorithms it was possible to find a combination of two stable reference genes with which to normalise qPCR data in mallards. These results highlight the importance of validating the choice of normalising reference genes before conducting gene expression studies in ducks. The fact that nearly all previous studies of the influence of pathogen infection on mallard gene expression have used a single, non-validated reference gene is problematic. The toolkit of putative reference genes provided here offers a solid foundation for future studies of gene expression in mallards and other waterfowl

A Panel of Stably Expressed Reference Genes for Real-Time qPCR Gene Expression Studies of Mallards (Anas platyrhynchos)

Determining which reference genes have the highest stability, and are therefore appropriate for normalising data, is a crucial step in the design of real-time quantitative PCR (qPCR) gene expression studies. This is particularly warranted in non-model and ecologically important species for which appropriate reference genes are lacking, such as the mallard-a key reservoir of many diseases with relevance for human and livestock health. Previous studies assessing gene expression changes as a consequence of infection in mallards have nearly universally used β-actin and/or GAPDH as reference genes without confirming their suitability as normalisers. The use of reference genes at random, without regard for stability of expression across treatment groups, can result in erroneous interpretation of data. Here, eleven putative reference genes for use in gene expression studies of the mallard were evaluated, across six different tissues, using a low pathogenic avian influenza A virus infection model. Tissue type influenced the selection of reference genes, whereby different genes were stable in blood, spleen, lung, gastrointestinal tract and colon. β-actin and GAPDH generally displayed low stability and are therefore inappropriate reference genes in many cases. The use of different algorithms (GeNorm and NormFinder) affected stability rankings, but for both algorithms it was possible to find a combination of two stable reference genes with which to normalise qPCR data in mallards. These results highlight the importance of validating the choice of normalising reference genes before conducting gene expression studies in ducks. The fact that nearly all previous studies of the influence of pathogen infection on mallard gene expression have used a single, non-validated reference gene is problematic. The toolkit of putative reference genes provided here offers a solid foundation for future studies of gene expression in mallards and other waterfowl

GeNorm stability rankings (M value) of eleven candidate reference genes amongst six mallard tissues.

<p>(A) Blood. (B) Spleen. (C) Liver. (D) GI2 (distal jejunum). (E) GI4 (distal ileum). (F) Colon. Data is plotted from least stable (left) to most stable (right) gene. Genes with an M value below 0.5 (red dashed line) are considered stable.</p

Gene expression papers in Mallard and Pekin ducks.

<p>This summary is limited to those studies assessing mRNA transcriptional changes of genes of interest in response to infection of live animals with a pathogen followed by qPCR profiling of gene expression.</p

NormFinder stability rankings of eleven candidate reference genes amongst six mallard tissues.

<p>(A) Blood. (B) Spleen. (C) Liver. (D) GI2 (distal jejunum). (E) GI4 (distal ileum). (F) Colon. Data is plotted from least stable (left) to most stable (right) gene.</p

The number of RGs required for data normalisation.

<p>Y-axis represents the GeNorm V value and the X-axis is V_i/j where “<i>i</i>” is V calculated for <i>n</i> genes and “<i>j</i>” is <i>n</i> + 1 genes. If the V value for a given comparison of V_i/j falls below 0.15 (red dashed line), then the “<i>i</i>” number of genes is sufficient for normalisation.</p

Selected reference genes per tissue.

<p>Combined stability value for the best combination of genes as calculated in (A) GeNorm and (B) NormFinder. For GeNorm, the number selected was that required to reach a threshold stability V value of lower than 0.15; for NormFinder the recommended combination of the two best genes are provided. Note that stability values are not directly comparable between GeNorm and NormFinder, as each algorithm uses its own stability index.</p

Primers used in this study.

<p>F denotes the forward primer and R the reverse primer. Annealing temperature (Ta) expressed in °C and length in base pairs (bp).</p

Expression levels of each putative RG per tissue.

<p>Expression level expressed in terms of Ct value whereby a lower Ct value represents higher expression, of the eleven putative reference genes (RGs) across six mallard tissues. (A) Blood. (B) Spleen. (C) Lung. (D) GI 2 (distal jejunum). (E) GI 4 (distal ileum). (F) Colon. Uninfected individuals are shown with blue triangles, infected individuals with black circles.</p

Acidithiobacillus ferrivorans SS3 presents little RNA transcript response related to cold stress during growth at 8 A degrees C suggesting it is a eurypsychrophile

Acidithiobacillus ferrivorans is an acidophilic bacterium that represents a substantial proportion of the microbial community in a low temperature mining waste stream. Due to its ability to grow at temperatures below 15 °C, it has previously been classified as ‘psychrotolerant’. Low temperature-adapted microorganisms have strategies to grow at cold temperatures such as the production of cold acclimation proteins, DEAD/DEAH box helicases, and compatible solutes plus increasing their cellular membrane fluidity. However, little is known about At. ferrivorans adaptation strategies employed during culture at its temperature extremes. In this study, we report the transcriptomic response of At. ferrivorans SS3 to culture at 8 °C compared to 20 °C. Analysis revealed 373 differentially expressed genes of which, the majority were of unknown function. Only few changes in transcript counts of genes previously described to be cold adaptation genes were detected. Instead, cells cultured at cold (8 °C) altered the expression of a wide range of genes ascribed to functions in transcription, translation, and energy production. It is, therefore, suggested that a temperature of 8 °C imposed little cold stress on At. ferrivorans, underlining its adaptation to growth in the cold as well as suggesting it should be classified as a ‘eurypsychrophile’