The influence of fie and met1 mutations and in vitro culture conditions on autonomous endosperm development in unfertilized ovules of Arabidopsis thaliana

In flowering plants, seeds are produced both sexually (double fertilization is required) and asexually via apomixis (meiotic reduction and egg fertilization are omitted). An apomictic-like pattern of endosperm development in planta is followed by fis mutants of sexual Arabidopsis thaliana. In our experiments in planta, autonomous endosperm (AE) developed in met1 mutants. Furthermore we obtained autonomous endosperm formation in vitro not only in unfertilized ovules of fie mutants but also in wild genotypes (Col-0, MET1/MET1, FIE/FIE) and met1 mutants. AE induction and development occurred in all genotypes on the each of the media used and in every trial. The frequency of AE was relatively high (51.2% ovaries) and genotype-dependent. AE induced in vitro represents a more advanced stage of development than AE induced in fie mutants in planta. This was manifested by a high number of nuclei surrounded by cytoplasm and organized in nuclear cytoplasmic domains (NCDs), nodule formation, division into characteristic regions, and cellularization. The high frequency of AE observed in homozygous met1 (met1/met1) mutants probably is due to accumulation of hypomethylation as an effect of the met1 mutation and the in vitro conditions. AE development was most advanced in FIE/fie mutants. We suggest that changes in the methylation of one or several genes in the DNA of Arabidopsis genotypes caused by in vitro conditions resulted in AE induction and/or further AE development

Mouse cytoplasmic dynein intermediate chains: identification of new isoforms, alternative splicing and tissue distribution of transcripts

BACKGROUND: Intracellular transport of cargoes including organelles, vesicles, signalling molecules, protein complexes, and RNAs, is essential for normal function of eukaryotic cells. The cytoplasmic dynein complex is an important motor that moves cargos along microtubule tracks within the cell. In mammals this multiprotein complex includes dynein intermediate chains 1 and 2 which are encoded by two genes, Dync1i1 and Dync1i2. These proteins are involved in dynein cargo binding and dynein complexes with different intermediate chains bind to specific cargoes, although the mechanisms to achieve this are not known. The DYNC1I1 and DYNC1I2 proteins are translated from different splice isoforms, and specific forms of each protein are essential for the function of different dynein complexes in neurons. METHODOLOGY/PRINCIPAL FINDINGS: Here we have undertaken a systematic survey of the dynein intermediate chain splice isoforms in mouse, basing our study on mRNA expression patterns in a range of tissues, and on bioinformatics analysis of mouse, rat and human genomic and cDNA sequences. We found a complex pattern of alternative splicing of both dynein intermediate chain genes, with maximum complexity in the embryonic and adult nervous system. We have found novel transcripts, including some with orthologues in human and rat, and a new promoter and alternative non-coding exon 1 for Dync1i2. CONCLUSIONS/SIGNIFICANCE: These data, including the cloned isoforms will be essential for understanding the role of intermediate chains in the cytoplasmic dynein complex, particularly their role in cargo binding within individual tissues including different brain regions

TDP-43 is a culprit in human neurodegeneration, and not just an innocent bystander

In 2006 the protein TDP-43 was identified as the major ubiquitinated component deposited in the inclusion bodies found in two human neurodegenerative diseases, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The pathogenesis of both disorders is unclear, although they are related by having some overlap of symptoms and now by the shared histopathology of TDP-43 deposition. Now, in 2008, several papers have been published in quick succession describing mutations in the TDP-43 gene, showing they can be a primary cause of amyotrophic lateral sclerosis. There are many precedents in neurodegenerative disease in which rare single-gene mutations have given great insight into understanding disease processes, which is why the TDP-43 mutations are potentially very important

Comparison of efficacy and safety of first-line palliative chemotherapy with EOX and mDCF regimens in patients with locally advanced inoperable or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma : a randomized phase 3 trial

The aim of the study was to compare efficacy and safety of first-line palliative chemotherapy with (EOX) epirubicin/oxaliplatin/capecitabine and (mDCF) docetaxel/cisplatin/5FU/leucovorin regimens for untreated advanced HER2-negative gastric or gastroesophageal junction adenocarcinoma. Fifty-six patients were randomly assigned to mDCF (docetaxel 40 mg/m(2) day 1, leucovorin 400 mg/m(2) day 1, 5FU 400 mg/m(2) bolus day 1, 5FU 1000 mg/m(2)/d days 1 and 2, cisplatin 40 mg/m(2) day 3) or EOX (epirubicin 50 mg/m(2) day 1, oxaliplatin 130 mg/m(2) day 1, capecitabine 1250 mg/m(2)/d days 1–21). The primary endpoint was overall survival. The median overall survival was 9.5 months with EOX and 11.9 months with mDCF (p = 0.135), while median progression-free survival was 6.4 and 6.8 months, respectively (p = 0.440). Two-year survival rate was 22.2 % with mDCF compared to 5.2 % with EOX. Patients in the EOX arm had more frequent reductions in chemotherapy doses (34.5 vs. 3.7 %; p = 0.010) and delays in subsequent chemotherapy cycles (82.8 vs. 63.0 %; p = 0.171). There was no statistically significant difference in the rates of grade 3–4 adverse events (EOX 79.3 vs. mDCF 61.5 %; p = 0.234). As compared with the mDCF, the EOX regimen was associated with more frequent nausea (34.5 vs. 15.4 %), thromboembolic events (13.8 vs. 7.7 %), abdominal pain (13.8 vs. 7.7 %) and grades 3–4 neutropenia (72.4 vs. 50.0 %), but lower incidences of anemia (44.8 vs. 61.5 %), mucositis (6.9 vs. 15.4 %) and peripheral neuropathy (6.9 vs. 15.4 %). In conclusion, the mDCF regimen was associated with a statistically nonsignificant 2.4-month longer median overall survival without an increase in toxicity. This trial is registered at ClinicalTrials.gov, number NCT02445209

Behavioral and Other Phenotypes in a Cytoplasmic Dynein Light Intermediate Chain 1 Mutant Mouse

The cytoplasmic dynein complex is fundamentally important to all eukaryotic cells for transporting a variety of essential cargoes along microtubules within the cell. This complex also plays more specialized roles in neurons. The complex consists of 11 types of protein that interact with each other and with external adaptors, regulators and cargoes. Despite the importance of the cytoplasmic dynein complex, we know comparatively little of the roles of each component protein, and in mammals few mutants exist that allow us to explore the effects of defects in dynein-controlled processes in the context of the whole organism. Here we have taken a genotype-driven approach in mouse (Mus musculus) to analyze the role of one subunit, the dynein light intermediate chain 1 (Dync1li1). We find that, surprisingly, an N235Y point mutation in this protein results in altered neuronal development, as shown from in vivo studies in the developing cortex, and analyses of electrophysiological function. Moreover, mutant mice display increased anxiety, thus linking dynein functions to a behavioral phenotype in mammals for the first time. These results demonstrate the important role that dynein-controlled processes play in the correct development and function of the mammalian nervous system

Fat4-Dchs1 signalling controls cell proliferation in developing vertebrae

The protocadherins Fat4 and Dchs1 act as a receptor-ligand pair to regulate many developmental processes in mice and humans, including development of the vertebrae. Based on conservation of function between Drosophila and mammals, Fat4-Dchs1 signalling has been proposed to regulate planar cell polarity (PCP) and activity of the Hippo effectors Yap and Taz, which regulate cell proliferation, survival and differentiation. There is strong evidence for Fat regulation of PCP in mammals but the link with the Hippo pathway is unclear. In Fat4(−/−) and Dchs1(−/−) mice, many vertebrae are split along the midline and fused across the anterior-posterior axis, suggesting that these defects might arise due to altered cell polarity and/or changes in cell proliferation/differentiation. We show that the somite and sclerotome are specified appropriately, the transcriptional network that drives early chondrogenesis is intact, and that cell polarity within the sclerotome is unperturbed. We find that the key defect in Fat4 and Dchs1 mutant mice is decreased proliferation in the early sclerotome. This results in fewer chondrogenic cells within the developing vertebral body, which fail to condense appropriately along the midline. Analysis of Fat4;Yap and Fat4;Taz double mutants, and expression of their transcriptional target Ctgf, indicates that Fat4-Dchs1 regulates vertebral development independently of Yap and Taz. Thus, we have identified a new pathway crucial for the development of the vertebrae and our data indicate that novel mechanisms of Fat4-Dchs1 signalling have evolved to control cell proliferation within the developing vertebrae

Methods for Developing Students’ Writing Skills in English Lessons of Form 4

Šis diplomdarbs ir rezultāts pētījumam, kas atklāj, kādas metodes ir vispiemērotākās studentu rakstīšanas prasmju attīstīšanai 4. klasē. Tēma tika izvēlēta, pamatojoties uz problēmu, ko autore jau iepriekš ir pamanījusi, proti, ka bērniem līdz 6. klasei ir nopietnas grūtības ar rakstīšanu. Autore izvēlējās divas 4. klases kā pētījuma izlasi, jo šiem skolēniem trūka rakstīšanas pamatprasmes angļu valodā. Atsevišķa gadījuma pētījuma ilga divus mēnešus. Prakses laikā pētījuma autors izmantoja četras dažādas skolēnu rakstīšanas prasmju attīstīšanas metodes, kas tika izvēlētas starp citām, pamatojoties uz teorētiskās literatūras avotiem un skolēnu īpatnībām, īpašībām un vēlmēm. Turklāt katra metode tika izmantota vairākas reizes, lai izdarītu pamatotus secinājumus. Pētījumā tika analizēti visi skolēnu rakstu darbi. Skolotāja prakses noslēgumā skolēni tika anketēti, lai noskaidrotu viņu attieksmi un viedokli par izmantotajām metodēm rakstīšanas prasmju attīstīšanai. Pētījuma rezultāti parādīja, ka vairums skolēniem patika kopēšanas un vizuālās metodes, un viņu darbu analīze uzrādīja, ka šīs divas metodes ir palīdzējušas attīstīt viņu rakstīšanas prasmes. Savukārt diktāts kā metode gandrīz katram 4. klases skolēnam likās sarežģīta un nelietderīga. Kaut arī no iegūtajiem datiem varēja izdarīt kādus secinājumus, tomēr būtu nepieciešams vairāk laika, lai izmēģinātu dažādas metodes un gūtu ticamākus rezultātus.This Diploma Paper is a result of the research discovering what methods are the most applicable for developing students’ writing skills in Form 4. The topic was chosen to explore the problem the author had noticed during her teaching practice that students until Form 6 had severe difficulties in writing. The author selected two Forms 4 as a research sample since these pupils lacked the necessary writing skills in English. The case study lasted for two complete months. During the practice, the researcher used four different methods for developing pupils’ English writing skills which were chosen among the other methods based on the theoretical literature and specific features, characteristics and preferences of the students. Besides, each method was used a couple of times to make valid conclusions. Later, all students’ written works were analysed. Apart from that, in the end of the author’s teaching practice the questionnaire was carried out in order to find out the pupils’ attitude and trustworthy opinions on methods they found helpful for developing their writing skills. The research data showed that most of the students enjoyed the use of copying and visual methods, and the analysis of their works proved that these two methods helped to develop their writing skills. On the contrary, almost every student in Form 4 found a dictation method confusing and unhelpful. Although it was possible to make conclusions based on the collected data, yet more time is necessary for trying out different methods in order to get more reliable results