Macroarray for studying chloroplast gene expression profiles associated with the initial development of wheat

Item does not contain fulltextOBJECTIVES: Feedback should facilitate learning, but within medical education it often fails to deliver on its promise. To better understand why feedback is challenging, we explored the unique perspectives of doctors who had also trained extensively in sport or music, aiming to: (i) distinguish the elements of the response to feedback that are determined by the individual learner from those determined by the learning culture, and (ii) understand how these elements interact in order to make recommendations for improving feedback in medical education. METHODS: Using a constructivist grounded theory approach, we conducted semi-structured interviews with 27 doctors or medical students who had high-level training and competitive or performance experience in sport (n = 15) or music (n = 12). Data were analysed iteratively using constant comparison. Key themes were identified and their relationships critically examined to derive a conceptual understanding of feedback and its impact. RESULTS: We identified three essential sources of influence on the meaning that feedback assumed: the individual learner; the characteristics of the feedback, and the learning culture. Individual learner traits, such as motivation and orientation toward feedback, appeared stable across learning contexts. Similarly, certain feedback characteristics, including specificity, credibility and actionability, were valued in sport, music and medicine alike. Learning culture influenced feedback in three ways: (i) by defining expectations for teachers and teacher-learner relationships; (ii) by establishing norms for and expectations of feedback, and (iii) by directing teachers' and learners' attention toward certain dimensions of performance. Learning culture therefore neither creates motivated learners nor defines 'good feedback'; rather, it creates the conditions and opportunities that allow good feedback to occur and learners to respond. CONCLUSIONS: An adequate understanding of feedback requires an integrated approach incorporating both the individual and the learning culture. Our research offers a clear direction for medicine's learning culture: normalise feedback; promote trusting teacher-learner relationships; define clear performance goals, and ensure that the goals of learners and teachers align

Expression of the chloroplast genome: modern concepts and experimental approaches

A unique feature of plants is the presence of two extranuclear genomes, chloroplasts and mitochondria. The chloroplast genome is relatively small, 100–120 genes, which encode less than 5 % of all proteins required for plastids to function. The cpDNA expression retains prokaryotic features, cotranscription in the operon, bacteria-like RNA polymerases and promoters, 70S ribosomes etc., also new characters appear such as uncoupling of transcription with translation, phage-type RNA polymerases, RNA editing, and splicing of primary transcripts. The interaction of the nucleus (nuclear genomes) and cytoplasm (plastid and mitochondrial genes) during plant development is necessary for proper development and adaptation to the environment. The aim of this review is to disclose the peculiarities of plastid genome expression. The way the genetic information in chloroplasts is used (transcription, editing, splicing, polyadenylation and translation) is consequently described. Furthermore, the importance of all expression machinery components in plant life is discussed. Modern approaches for RNA pool study are described and critical points of nuclear-cytoplasmic interaction in the functions of chloroplasts are revealed. The information about the most important factors of nuclear-cytoplasmic signaling in higher plants (sigma factors and PPR proteins encoded by the nucleus) are reviewed. Thus, the multilevelness and viability of plastid genome expression regula­tion in plant cells and interdependence of the pro­cesses in different compartments is proved. A summary of the latest studies of the expression of the plastid genome using genetic chips (microarrays, macroarrays) is provided. Original results are presented

The study of organelle DNA variability in alloplasmic barley lines in the NGS era

Alloplasmic lines are a suitable model for studying molecular coevolution and interrelations between genetic systems of plant cells. Whole chloroplast (cp) and mitochondrial (mt) genome sequences were obtained by the MiSeq System (Illumina). Organelle DNA samples were prepared from a set of 12 alloplasmic barley lines with different cytoplasms of Hordeum vulgare ssp. spontaneum and H. vulgare ssp. vulgare, as well as from their paternal varieties. A bioinformatic approach for analysis of NGS data obtained on an organellar DNA mix has been developed and verified. A comparative study of Hordeum organelle genomes' variability and disposition of polymorphic loci was conducted. Eight types of chloroplast DNA and 5 types of mitochondrial DNA were distinguished for the barley sample set examined. These results were compared with the previous data of a restriction fragment length polymorphism (RFLP) study of organelle DNAs for the same material. Formerly established data about a field evaluation of alloplasmic barley lines were revised in the light of information about organelle genomes gained after NGS. Totally 17 polymorphic loci were found at exons of chloroplast genomes. Seven of the SNPs were located in the genes of the Ndh complex. The nonsynonymous changes of nucleotides were detected in the matK, rpoCI, ndhK, ndhG and infA genes. Some of the SNPs detected are very similar in codon position and in the type of amino acid substitution to the places where RNA editing can occur. Thus, these results outline new perspectives for the future study of nuclear-cytoplasmic interactions in alloplasmic lines

Spectrum of Genetic Changes in Patients with Non-Syndromic Hearing Impairment and Extremely High Carrier Frequency of 35delG GJB2 Mutation in Belarus

The genetic nature of sensorineural hearing loss (SNHL) has so far been studied for many ethnic groups in various parts of the world. The single-nucleotide guanine deletion (35delG) of the GJB2 gene coding for connexin 26 was shown to be the main genetic cause of autosomal recessive deafness among Europeans. Here we present the results of the first study of GJB2 and three mitochondrial mutations among two groups of Belarusian inhabitants: native people with normal hearing (757 persons) and 391 young patients with non-syndromic SNHL. We have found an extremely high carrier frequency of 35delG GJB2 mutation in Belarus −5.7%. This point deletion has also been detected in 53% of the patients with SNHL. The 312del14 GJB2 was the second most common mutation in the Belarus patient cohort. Mitochondrial A1555G mt-RNR1 substitution was found in two SNHL patients (0.55%) but none were found in the population cohort. No individuals carried the A7445G mutation of mitochondrial mt-TS1. G7444A as well as T961G substitutions were detected in mitochondrial mt-RNR1 at a rate of about 1% both in the patient and population cohorts. A possible reason for Belarusians having the highest mutation carrier frequency in Europe 35delG is discussed