Polymorphism and Divergence in Two Willow Species, Salix viminalis L. and Salix schwerinii E. Wolf

We investigated species divergence, present and past gene flow, levels of nucleotide polymorphism, and linkage disequilibrium in two willows from the plant genus Salix. Salix belongs together with Populus to the Salicaceae family; however, most population genetic studies of Salicaceae have been performed in Populus, the model genus in forest biology. Here we present a study on two closely related willow species Salix viminalis and S. schwerinii, in which we have resequenced 33 and 32 nuclear gene segments representing parts of 18 nuclear loci in 24 individuals for each species. We used coalescent simulations and estimated the split time to around 600,000 years ago and found that there is currently limited gene flow between the species. Mean intronic nucleotide diversity across gene segments was slightly higher in S. schwerinii (πi = 0.00849) than in S. viminalis (πi = 0.00655). Compared with other angiosperm trees, the two willows harbor intermediate levels of silent polymorphisms. The decay of linkage disequilibrium was slower in S. viminalis compared with S. schwerinii, and we speculate that this is due to different demographic histories as S. viminalis has been partly domesticated in Europe

Fragmentation of tRNA in Phytophthora infestans asexual life cycle stages and during host plant infection

The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host.Results: To identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line.Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs with elevated levels during infection of potato by P. infestans

A calibration method for non-overlapping cameras based on mirrored phase target

A novel calibration method for non-overlapping cameras is proposed in this paper. A LCD screen is used as a phase target to display two groups of orthogonal phase-shifted sinusoidal patterns during the calibration process. Through a mirror reflection, the phase target is captured by the cameras respectively. The relations between each camera and the phase target can be obtained according the proposed algorithm. Then the relation between the cameras can be calculated by treating the phase target as an intermediate value. The proposed method is more flexible than conventional mirror-based approach, because it do not require the common identification points and is robust to out-of-focus images. Both simulation work and experimental results show the proposed calibration method has a good result in calibrating a non-overlapping cameras system

Симптоматические выражения с семантикой проявления радости в хинди и в русском языке

ВУЗЫВЫСШИЕ УЧЕБНЫЕ ЗАВЕДЕНИЯОБРАЗОВАНИЕ МЕДИЦИНСКОЕСТУДЕНТЫ МЕДИЦИНСКИХ УЧЕБНЫХ ЗАВЕДЕНИЙИНОСТРАННЫЕ СТУДЕНТЫРУССКИЙ ЯЗЫКСЕМАНТИКАСИМПТОМАТИЧЕСКИЕ ВЫРАЖЕНИЯХИНДИРАДОСТ

Трансформация культуры чтения в цифровую эпоху как показатель цивилизационных сдвигов

Материалы X Международной научной конференции 25–26 мая 2017 г

Genetic structure and dispersal in plant populations

This thesis focuses on the spatial structure and methods to identify spatial structure in plants. Methods that investigate genetic structure can mainly be divided into equilibrium methods that reveal summed dispersal over many generations, and cluster methods, that reveal more recent dispersal events. Depending on the spatial level, local or global, suitable methods are different. The thesis consists of four papers. The first explores the spatial genetic structure in two epiphytic bryophytes that have different dispersal strategies (Orthotrichum speciosum and O. obtusifolium) using three different approaches based on pairwise kinship coefficients assessed from AFLP data. The spatial kinship structure was detected with both autocorrelation analysis and generalized additive models, but linear regression failed to detect any structure in O. speciosum. In the second paper the spatial genetic structure in marginal populations of the forest tree Quercus robur is investigated at both local and regional scales. At the local scale, dispersal kernels as estimated using maximum likelihood parentage methods showed to be comparable to results acquired in central located populations. At the regional scale the degree of isolation at the margin of the distribution is shown. The third paper compares a number of sibship clustering methods. It was found that the performances of the sibship reconstruction algorithms are strongly dependent on fulfilling the assumptions of the model and that using an overly simple model produced very unreliable results. The amount of information included in the model affected the results; models including all the available information outperformed the models using only a subset of the information. In the last paper we show that the number of clusters as estimated by the software Structurama depends on sample size. At high number of subpopulations, the estimated number of clusters tends to be grossly underestimated when the number of sampled individuals per subpopulation is low

Genetic structure and dispersal in plant populations

This thesis focuses on the spatial structure and methods to identify spatial structure in plants. Methods that investigate genetic structure can mainly be divided into equilibrium methods that reveal summed dispersal over many generations, and cluster methods, that reveal more recent dispersal events. Depending on the spatial level, local or global, suitable methods are different. The thesis consists of four papers. The first explores the spatial genetic structure in two epiphytic bryophytes that have different dispersal strategies (Orthotrichum speciosum and O. obtusifolium) using three different approaches based on pairwise kinship coefficients assessed from AFLP data. The spatial kinship structure was detected with both autocorrelation analysis and generalized additive models, but linear regression failed to detect any structure in O. speciosum. In the second paper the spatial genetic structure in marginal populations of the forest tree Quercus robur is investigated at both local and regional scales. At the local scale, dispersal kernels as estimated using maximum likelihood parentage methods showed to be comparable to results acquired in central located populations. At the regional scale the degree of isolation at the margin of the distribution is shown. The third paper compares a number of sibship clustering methods. It was found that the performances of the sibship reconstruction algorithms are strongly dependent on fulfilling the assumptions of the model and that using an overly simple model produced very unreliable results. The amount of information included in the model affected the results; models including all the available information outperformed the models using only a subset of the information. In the last paper we show that the number of clusters as estimated by the software Structurama depends on sample size. At high number of subpopulations, the estimated number of clusters tends to be grossly underestimated when the number of sampled individuals per subpopulation is low

Measurement of abrasive flow in watercuttingmachines

The content of the following report is the summarized result of three students thesis at Blekinge Institute of Technology in co-operation with Water Jet Sweden AB. This report will give the reader a description of principles how to measure the abrasive mass flow in a waterjet cutting system. The work began with a visit to Water Jet Sweden AB to get a closer look at the problem. When the analysis of the problem was done the criteria were defined in the form of demands and desires. The main task of the criteria was to guide the search for the solution. The work proceeded with an extensive search for abrasive flow meters along with obtaining information about flow measurement in general. When the search for abrasive flow meters resulted in nothing all the efforts were concentrated on finding a principle of measurement that could cope with the criteria. A number of commonly accepted principles for measurement of mass flow was studied and evaluated. Those passing the evaluation were subject to another more extensive review. In this review the only conclusion was that none of the principles could be dismissed without practical testing. Water Jet Sweden AB were asked which principle/principles of measurement they were most interested in. After coming to an agreement two closely related principles of measurement were chosen to undergo practical studies. A number of different abrasive flows were simulated and in some cases a distinct variation of the signal value could be observed. Everyone involved in this project knew from the beginning that it was extensive. Even though no prototype was presented, this work represents a good foundation for future development.Innehållet i följande rapport är det sammanfattade resultatet av tre studenters examensarbete på Blekinge Tekniska Högskola i samarbete med Water Jet Sweden AB. Rapporten åskådliggör vägen fram till en principiell beskrivning av hur man kan gå till väga för att mäta flödet av abrasiv i en vatten–skärningsmaskin. Arbetet inleddes med ett besök på Water Jet Sweden AB för att närmare analysera problemet. När detta väl var klart definierades de kriterier, i form av krav och önskemål, som har till uppgift att styra sökandet efter en lösning i rätt riktning. Arbetet fortskred med en omfattande sökning efter redan färdiga abrasivflödesgivare parallellt med inhämtning av information rörande flödesmätning i allmänhet. Då det tidigare inte gav något resultat övergick ansträngningarna mot att finna en mätprincip som skulle klara de uppställda kriterierna. Ett flertal allmänt vedertagna principer för att mäta massflöde studerades och utvärderades. De som klarade utvärderingen gick vidare till en djupare granskning för att minska antalet ytterliggare. Men det visade sig vara svårt att avfärda någon av de mätprinciper som passerat första granskningen utan att utföra några praktiska försök. Water Jet Sweden AB tillfrågades om vilken/vilka mätprinciper som de ansåg vara mest intressanta att gå vidare med. Efter överenskommelse valdes två närbesläktade mätprinciper ut för praktiska studier. Olika abrasivflöden simulerades varvid en förändring av mätsignalen i vissa fall kunde registreras. Projektet var redan från början erkänt omfattande och även om projektdeltagarna inte lagt fram ett färdigt produktförslag har grunden för ett fortsatt arbete utformats

Major latex protein-like encoding genes contribute to Rhizoctonia solani defense responses in sugar beet

Sugar beets are attacked by several pathogens that cause root damages. Rhizoctonia (Greek for "root killer") is one of them. Rhizoctonia root rot has become an increasing problem for sugar beet production and to decrease yield losses agronomical measures are adopted. Here, two partially resistant and two susceptible sugar beet genotypes were used for transcriptome analysis to discover new defense genes to this fungal disease, information to be implemented in molecular resistance breeding. Among 217 transcripts with increased expression at 2 days post-infection (dpi), three resistance-like genes were found. These genes were not significantly elevated at 5 dpi, a time point when increased expression of three Bet v I/Major latex protein (MLP) homologous genes BvMLP1, BvMLP2 and BvML3 was observed in the partially resistant genotypes. Quantitative RT-PCR analysis on diseased sugar beet seedlings validated the activity of BvMLP1 and BvMLP3 observed in the transcriptome during challenge by R. solani. The three BvMLP genes were cloned and overexpressed in Arabidopsis thaliana to further dissect their individual contribution. Transgenic plants were also compared to T-DNA mutants of orthologous MLP genes. Plants overexpressing BvMLP1 and BvMLP3 showed significantly less infection whereas additive effects were seen on Atmlp1/Atmlp3 double mutants. The data suggest that BvMLP1 and BvMLP3 may contribute to the reduction of the Rhizoctonia root rot disease in sugar beet. Impact on the defense reaction from other differential expressed genes observed in the study is discussed

Dominance of Mating Type A1 and Indication of Epigenetic Effects During Early Stages of Mating in Phytophthora infestans

The potato late blight pathogen Phytophthora infestans has both an asexual and a sexual mode of reproduction. In Scandinavia, the pathogen is reproducing sexually on a regular basis, whereas clonal lineages dominate in other geographical regions. This study aimed at elucidating events or key genes underlying this difference in sexual behavior. First, the transcriptomes of eight strains, known as either clonal or sexual, were compared during early stages of mating. Principal component analysis (PCA) divided the samples in two clusters A and B and a clear grouping of the mating samples together with the A1 mating type parents was observed. Induction of genes encoding DNA adenine N6-methylation (6mA) methyl-transferases clearly showed a bias toward the cluster A. In contrast, the Avrblb2 effector gene family was highly induced in most of the mating samples and was associated with cluster B in the PCA, similarly to genes coding for acetyl-transferases, which play an important role in RXLR modification prior to secretion. Avrblb2 knock-down strains displayed a reduction in virulence and oospore formation, suggesting a role during the mating process. In conclusion, a number of gene candidates important for the reproductive processes were revealed. The results suggest a possible epigenetic influence and involvement of specific RXLR effectors in mating-related processes