Expression stability of putative reference genes in equine endometrial, testicular, and conceptus tissues

<p>Abstract</p> <p>Background</p> <p>Quantitative RT-PCR data are commonly normalized using a reference gene. A reference gene is a transcript which expression does not differ in the tissue of interest independent of the experimental condition. The objective of this study was to evaluate the stability of mRNA expression levels of putative reference genes in three different types of equine tissue, endometrial, testicular, and conceptus tissue.</p> <p>Findings</p> <p>The expression stability of four (uterine tissue) and six (testicular and conceptus tissue) was assessed using descriptive data analysis and the software programs Normfinder and geNorm. In uterine samples, <it>18S </it>showed the largest degree of variation in expression while <it>GAPDH</it>, <it>B2M</it>, and <it>ACTB </it>were stably expressed. <it>B2M </it>and <it>GAPDH </it>were identified as the most stably expressed genes in testicular samples, while <it>18S </it>showed some extent of regulation between samples. Conceptus tissue overall was characterized by very low variability of the transcripts analyzed with <it>GAPDH</it>, <it>YWHZ</it>, and 18S being the most stably expressed genes.</p> <p>Conclusions</p> <p>In equine endometrium, <it>GAPDH</it>, <it>B2M</it>, and <it>ACTB </it>transcript levels are equally stable, while <it>18S </it>is less stably expressed. In testes and associated structures, <it>B2M </it>and <it>GAPDH </it>are the transcripts showing the least amount of variation, while in conceptus tissue <it>GAPDH</it>, <it>YWHZ</it>, and <it>18S </it>were identified as the most suitable reference genes. Overall, transcripts analyzed in conceptus tissue were characterized by less variation than transcripts analyzed in uterine and testicular tissue.</p

The new principal and the diagnosis of school culture

M.Ed. (Education Management)Taking up the first principalship is a demanding career transition involving emergency professional development, not only for the new principal to move from the role of teacher and administrator, but for him to successfully diagnose a new culture. The degree of success that a new principal -has in discovering, understanding, developing further and managing a new school culture within the first year of his appointment, will determine his overall effectiveness in managing the new school. Against this background, the focus of this research paper will be to identify and define school culture. Included here will be a discussion of what constitutes culture, the process of acculturation, the influence of sub-cultures and the impediment of culture on both management and change. The role of the new principal in managing and where necessary changing existing culture in a school is described in this paper. The problem areas likely to be encountered and the solutions to these problems are also discussed. A strategy is proposed to assist future new principals with the problem of managing existing culture in the school. Divided into three parts, the strategy assist the new principal to read the existing culture of the school. Secondly, it proposes that the new principal follows a collaborative process for the review of and transformation of existing school culture. The final part of the strategy is to revise and establish innovative communication networks to ensure the strategy's overall success

An RNA spiking method demonstrates that 18S rRNA is regulated by progesterone in the mouse uterus.

C1 - Journal Articles Referee

False Susceptibility of Enterococci to Aminoglycosides With Blood-Enriched Mueller-Hinton Agar for Disk Susceptibility Testing

Disk diffusion susceptibility tests for enterococci are frequently modified by adding 5% sheep blood (SB) to Mueller-Hinton agar; the performance standards from the National Committee for Clinical Laboratory Standards sanction this addition. Susceptibility testing of aminoglycoside antibiotics is not recommended for enterococci; in actual practice, however, some laboratories do include aminoglycoside antibiotics routinely, and others may test upon request or in selected situations. In examining 50 clinical isolates of enterococci, SB-enriched Mueller-Hinton agar frequently gave enlarged zone sizes that falsely indicated susceptibility (72% for gentamicin and tobramycin), with the average increase in zone size being 6.3 and 7.6 mm, respectively. Comparison agar dilution MICs demonstrated uniform resistance, with or without added SB. The effect was shown to be caused by heme in concentrations as low as 0.03 micrograms/ml, which, when combined with aminoglycoside antibiotics, caused a synergistic growth inhibition of the enterococci, resulting in larger aminoglycoside antibiotic zones. We postulate that the heme effect is related to a catalytic cleavage of intracellular H2O2 and resultant lipid peroxidation. No other organism or antimicrobial agent tested demonstrated a similar effect, although other investigators have shown a similar phenomenon with the broad-spectrum cephalosporins. Because enterococci grow well and give accurate susceptibility results on Mueller-Hinton agar without SB supplementation and because of the spectrum of definable problems with a number of antimicrobial agents, we recommend that enterococci routinely be tested without SB

Membrane filter contact technique for bacteriological sampling of moist surfaces

We used a membrane filter contact technique to pick up and grow bacteria from artificially contaminated surfaces. We were able to recover individual colony-forming units (CFU) of Staphylococcus aureus from a moist agar surface more efficiently with 3- and 5- micron membrane filters than with Rodac plates, velvet pads, velveteen pads, or smaller-pore membrane filters. The effective transfer of bacteria with the 3- and 5-micron membrane filters was 0.96 +/- 0.04 (standard error of the mean) and 0.99 +/- 0.04, respectively, as compared to 0.49 +/- 0.03 for Rodac plates, 0.09 +/- 0.01 velvet pad imprints, 0.05 +/- 0.01 for velveteen pad imprints, 0.27 +/- 0.02 for velvet pad rinses, 0.005 +/- 0.001 for velveteen pad rinses, 0.39 +/- 0.02 for 0.45-micron filters, and 0.85 +/-0.05 for 1.2 micron filters. In addition, the recovery of S. aureus from contaminated bovine muscle surfaces with the 5-microns membrane filter was similar to that of quantitative dilutions of biopsy material and was significantly higher than the recovery from Rodac plates. The 5-microns membrane filters on a paddle recovered 52 +/- 5 CFU/cm2 from artificially contaminated bovine skeletal muscle, the quantitative dilutions of biopsy recovered 69 +/- 5 CFU/cm2, and the Rodac plate recovered 5 +/- 3 CFU/cm2. Sampling of moist surfaces by the membrane filter contact technique is easy to perform and highly efficient; our data suggest that it could be employed for cultures of clinical surfaces such as surgical wounds or burns.</jats:p