Callus formation and somatic embryogenesis : from leaf cultures of orchardgrass (Dactylis glomerata L.)

The purpose of this study was to demonstrate callus formation and plant regeneration from orchardgrass (Dactylis glomerata L.) leaf tissue cultured in vitro. Vegetative tillers were removed from greenhouse grown plants and the two or three innermost leaves were split longitudinally at the midrib. Beginning at the basal end, six sections 3 mm long were cut from each leaf half and plated on a Schenk and Hildebrandt (SH) medium with 30 μM 3,6-dichloro-o-anisic acid (dicamba). Initially, leaves from 86 plants were cultured and 14 plants produced a callus which regenerated plants via organogenesis. There was a decline in the frequency of leaf sections that produced callus or regenerated plants with increasing distance, both spatial and temporal, from the shoot apical meristem. Somatic embryos were observed on one callus piece. Plants grown from these embryos demonstrated a dramatic increase in embryogenic potential compared to seed grown plants. Somatic embryos formed on callus and directly on the leaf sections. Direct embryos were shown by histology to arise from mesophyll tissue. Somatic embryos, either singly or attached to the callus mass, germinated and grew into plantlets when placed on auxin-free medium. Several factors including leaf characteristics, photoperiod and temperature combinations, auxin, and auxin concentrations were tested for their influence on the leaf culture system. Both the abaxial and adaxial leaf surfaces responded similarly in culture. Photoperiod and temperature combinations were significant for the number of sections that callused and callus fresh weight. In a second experiment using embryogenic genotypes, initial culture temperatures were not significant for the number of somatic embryos produced. Dicamba concentrations of 15 and 30 μM were significantly better than other dicamba concentrations ranging from 0 to 240 μM for callus fresh weight and number of shoots counted. The optimum 2,4-dichlorophenoxyacetic acid (2,4-D) concentration was 10 μM for somatic embryo formation. However, it was not significantly better than 30 μM dicamba. In field observations, there was variation for several agronomic characters within a group of plants regenerated from the same seed grown plant and among groups of plants regenerated from different seed grown plants. Thirteen additional embryogenic genotypes were identified from 200 plants of the cultivar \u27Potomac\u27 and 48 plants from germ plasm accessions grown from seed

The role of change management in successfully implementing a retail enterprise resource planning solution

The focus of this research questions the role of change management in successfully implementing an Enterprise Resource Planning solution in the retail industry. The importance of the study could reveal a change approach more useful and relevant to the retail industry and offer opportunities for further research in this industry.Graduate School of Business LeadershipM.B.A

Depletion of polycistronic transcripts using short interfering RNAs: cDNA synthesis method affects levels of non-targeted genes determined by quantitative PCR.

BACKGROUND: Short interfering RNAs (siRNAs) are often used to deplete viral polycistronic transcripts, such as those encoded by human papillomavirus (HPV). There are conflicting data in the literature concerning how siRNAs targeting one HPV gene can affect levels of other genes in the polycistronic transcripts. We hypothesised that the conflict might be partly explained by the method of cDNA synthesis used prior to transcript quantification. FINDINGS: We treated HPV16-positive cervical keratinocytes with siRNAs targeting the HPV16 E7 gene and used quantitative PCR to compare transcript levels of E7 with those of E6 and E2, viral genes located upstream and downstream of the target site respectively. We compared our findings from cDNA generated using oligo-dT primers alone with those from cDNA generated using a combination of random hexamer and oligo-dT primers. Our data show that when polycistronic transcripts are targeted by siRNAs, there is a period when untranslatable cleaved mRNA upstream of the siRNA binding site remains detectable by PCR, if cDNA is generated using random hexamer primers. Such false indications of mRNA abundance are avoided using oligo-dT primers. The period corresponds to the time taken for siRNA activity and degradation of the cleaved transcripts. Genes downstream of the siRNA binding site are detectable during this interval, regardless of how the cDNA is generated. CONCLUSIONS: These data emphasise the importance of the cDNA synthesis method used when measuring transcript abundance following siRNA depletion of polycistronic transcripts. They provide a partial explanation for erroneous reports suggesting that siRNAs targeting HPV E7 can have gene-specific effects.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

The rectal route of medicine administration for children: Let's get to the bottom of it!

Aims: Research around paediatric rectal drug delivery has previously been based on views of parents and healthcare workers. The aim of this exploratory study was to gauge whether children and young adults in the UK were comfortable with the idea of rectal drug delivery. / Methods: Eleven children from a pre-existing patient and public advisory group were involved in the session. Rectal drug delivery was explained and group participants were asked a series of questions. Responses were discussed in a group and recorded individually. /Results: Of the group, 27% would consider the rectal route, while 64% said it depended on other options available. The primary concern focused on potential for abusive misuse by others. Participants thought this would be overcome if the child could self-administer, although there was also concern about the process of self-administration. / Conclusions: Not all children in the UK are against rectal drug delivery, but education is needed to teach children to self-administer medication in this way