Phenylalanine ammonia-lyase (PAL) gene activity in response to proline and tyrosine in rosemary callus culture

Phenylalanine ammonia-lyase (PAL) catalyzes the biosynthesis of rosmarinic acid (RA), tyrosine and phenylalanine are the precursors of RA, while proline drives metabolite precursors toward Shikimate and phenylpropanoid pathway ending with the production of RA. The aim of this study was to investigate the PAL gene activity in the callus of rosemary (Rosmarinus officinalis) due to exogenous application of L-proline and L-tyrosine. Four different concentrations of L-proline and L-tyrosine (0, 4, 5 and 6 mM, and 0, 0.4, 0.6 and 0.8 gm/L) respectively, were added to the basal Murashige and Skoog (MS) medium. The expression of the PAL gene was investigated and compared with the callus RA production. It was found that RA production increased significantly at low proline application (4 mM), on the other hand, tyrosine application at low concentrations had no effect on RA accumulation, while high tyrosine concentration (0.8 g/L) increased RA accumulation. When comparing PAL gene activity and RA production in callus tissues, it was found that they were correlated. Proline application alone at 4 mM or tyrosine alone at 0.8 g/L enhanced PAL gene activity, and also combining both proline at 4 mM and tyrosine at 0.8 g/L enhanced PAL gene activity and produced the highest RA accumulation in callus tissues [0.047 mg/g freash weight (fw)].Key words: Phenylalanine ammonia-lyase (PAL), gene expression, rosmarinic acid, Rosmarinus officinalis, tyrosine, proline

A programme of studies including assessment of diagnostic accuracy of school hearing screening tests and a cost-effectiveness model of school entry hearing screening programmes

Background Identification of permanent hearing impairment at the earliest possible age is crucial to maximise the development of speech and language. Universal newborn hearing screening identifies the majority of the 1 in 1000 children born with a hearing impairment, but later onset can occur at any time and there is no optimum time for further screening. A universal but non-standardised school entry screening (SES) programme is in place in many parts of the UK but its value is questioned. Objectives To evaluate the diagnostic accuracy of hearing screening tests and the cost-effectiveness of the SES programme in the UK. Design Systematic review, case–control diagnostic accuracy study, comparison of routinely collected data for services with and without a SES programme, parental questionnaires, observation of practical implementation and cost-effectiveness modelling. Setting Second- and third-tier audiology services; community. Participants Children aged 4–6 years and their parents. Main outcome measures Diagnostic accuracy of two hearing screening devices, referral rate and source, yield, age at referral and cost per quality-adjusted life-year. Results The review of diagnostic accuracy studies concluded that research to date demonstrates marked variability in the design, methodological quality and results. The pure-tone screen (PTS) (Amplivox, Eynsham, UK) and HearCheck (HC) screener (Siemens, Frimley, UK) devices had high sensitivity (PTS ≥ 89%, HC ≥ 83%) and specificity (PTS ≥ 78%, HC ≥ 83%) for identifying hearing impairment. The rate of referral for hearing problems was 36% lower with SES (Nottingham) relative to no SES (Cambridge) [rate ratio 0.64, 95% confidence interval (CI) 0.59 to 0.69; p < 0.001]. The yield of confirmed cases did not differ between areas with and without SES (rate ratio 0.82, 95% CI 0.63 to 1.06; p = 0.12). The mean age of referral did not differ between areas with and without SES for all referrals but children with confirmed hearing impairment were older at referral in the site with SES (mean age difference 0.47 years, 95% CI 0.24 to 0.70 years; p < 0.001). Parental responses revealed that the consequences to the family of the referral process are minor. A SES programme is unlikely to be cost-effective and, using base-case assumptions, is dominated by a no screening strategy. A SES programme could be cost-effective if there are fewer referrals associated with SES programmes or if referrals occur more quickly with SES programmes. Conclusions A SES programme using the PTS or HC screener is unlikely to be effective in increasing the identified number of cases with hearing impairment and lowering the average age at identification and is therefore unlikely to represent good value for money. This finding is, however, critically dependent on the results of the observational study comparing Nottingham and Cambridge, which has limitations. The following are suggested: systematic reviews of the accuracy of devices used to measure hearing at school entry; characterisation and measurement of the cost-effectiveness of different approaches to the ad-hoc referral system; examination of programme specificity as opposed to test specificity; further observational comparative studies of different programmes; and opportunistic trials of withdrawal of SES programmes

Role of DNA methylation in head and neck cancer

Head and neck cancer (HNC) is a heterogenous and complex entity including diverse anatomical sites and a variety of tumor types displaying unique characteristics and different etilogies. Both environmental and genetic factors play a role in the development of the disease, but the underlying mechanism is still far from clear. Previous studies suggest that alterations in the genes acting in cellular signal pathways may contribute to head and neck carcinogenesis. In cancer, DNA methylation patterns display specific aberrations even in the early and precancerous stages and may confer susceptibility to further genetic or epigenetic changes. Silencing of the genes by hypermethylation or induction of oncogenes by promoter hypomethylation are frequent mechanisms in different types of cancer and achieve increasing diagnostic and therapeutic importance since the changes are reversible. Therefore, methylation analysis may provide promising clinical applications, including the development of new biomarkers and prediction of the therapeutic response or prognosis. In this review, we aimed to analyze the available information indicating a role for the epigenetic changes in HNC

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Genome polymorphism markers and stress genes expression for identifying turf species

Reactive oxygen species (ROS) are produced in both stressed and unstressed cells. Superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) play an important role in the defense against ROS. Eight different turf grass species were used in order to detect their ability to withstand environmental stress through investigating SOD and PAL gene expression and also the genetic relationship among them using random amplified polymorphic DNA (RAPD) molecular markers. The levels of expression of PAL, SOD genes and mRNA varied with the type of turf; both PAL and SOD gene expressions were low in cold season turf grasses (kentucky blue grass and fine fescue), moderate for bermuda hybrids (tifgreen and tifway) and high in Paspalum vaginatum. Primer 3 (UBC-245) can be used to distinguish between Paspalum species, also between common burmuda (Cynodon dactylon) and burmuda hybrids. It was concluded that hot season genera can withstand environmental stress more than cold season ones since they have more SOD and PAL gene expressions. Also, DNA markers can be used to differentiate between different turf genera which are hard to be differentiated morphologically.Keywords: Turf, superoxide dismutase, phenylalanine ammonia lyase, RAPD markers, oligonucleotide primers, burmuda hybrids.African Journal of Biotechnology, Vol 13(24) 2394-239