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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Ecology and population genetic structure of strains of Teretrius nigrescens (Coleoptera: Histeridae), predator of Prostephanus truncatus (Coleoptera: Bostrichidae) / Bonaventure Omondi Aman Oduor

Oduor, Bonaventure Omondi Aman January 2009 (has links)
The larger grain borer (LGB) Prostephanus truncatus (Horn) is the most important pest of farm stored maize and cassava in Africa. This alien invasive species was introduced into the continent from Mesoamerica in the late 1970s and by 2008 had spread to at least 18 countries. In contrast to indigenous primary storage pests, LGB exists as on-farm and as wild populations, hence, sustainable control must target both environments. Biological control is especially attractive for wild populations to reduce early season grain store infestation, while cultural and chemical methods are useful to protect stored produce directly. Two populations of the predator Teretrius nigrescens Lewis were introduced into several African countries' as a biocontrol agent. It has shown long-term success and cost effective control in warm-humid areas. Control has however not been successful in cool and hot-dry zones. The aim of this study was to investigate the possible underlying genetic and ecological explanations for these observations and the possibility of joint use of molecular markers and ecological parameters in the development of sustainable control strategies. A 28-month baseline monitoring and recovery activity was done in from 2004 in five regions in Kenya along an east-westerly transect. Monitoring and live sample collection was also done in the original outbreak area in eastern Kenya. There was greater LGB flight activity in western Kenya (high potential maize production area) than the low potential areas. Very few T. nigrescens were recovered, solely in the eastern regions. LGB flight activity followed a seasonal pattern mostly related to changes in the relative humidity at 12:00, rainfall and dew point temperature but with a 3 - 4 week lag. A linear predictive model based on these factors predicted 27 % of the observed flight activity. The survival and predation of five strains of T. nigrescens were compared at eight temperature levels between 15 °C and 36 °C at low and high humidity. All the strains of T. nigrescens exerted a significant reduction of LGB population build-up between 21 °C and 33 °C with generally better performance under humid conditions. There was no evidence of T. nigrescens development at 15 °C. At 18 °C, T. nigrescens oviposition and development was observed but the effect on LGB did not differ significantly from the control. The KARI population was the least effective in preventing grain damage at lower temperatures, but performed better than other strains above 30 °C at low humidity conditions. There was no control at 18 °C and 36 °C under both high and low humidity conditions. Since the extent of genetic differentiation in T. nigrescens was unclear from prior studies, several molecular marker techniques were progressively used. The RAPD-PCR did not reveal any genetic diversity between geographical populations. A 1000bp region of the mitochondrial mtCOI gene revealed two distinct clades differing consistently at 26 segregating sites. The two clades can be identified by simple PCR-RFLP procedure using single or double sequential restriction with EcoR1, HincII, RsaI and DdeI digestion. However, the two lineages co-exist among the mid-altitude Central American populations. The internal transcribed spacer regions ITS1 and ITS2 with some neighbouring coding sequences of the ribosomal DNA were cloned and sequenced. The spacer regions were so variable in length and sequence between T. nigrescens and related Histeridae species that direct sequence alignment was not meaningful. Within T. nigrescens, there was intragenomic variability of the spacer regions mostly involving insertions and deletions of variable tandem repeat units predominantly within the ITS regions. The short flanking coding (18S, 5.8S and 21S) regions were conserved across populations and six other Histeridae species. There was no significant secondary structure variation of the ITS regions among populations of T. nigrescens. Twenty-four novel variable microsatellite markers were developed and tested on the Honduras populations. Alleles per locus ranged between two and twelve with observed heterozygosity between 0.048 and 0.646. Six loci deviated significantly from Hardy Weinberg Equilibrium and possibly had null alleles. The success of microsatellite amplification in outgroup species and variability of markers declined with an increase in the phylogenetic distance between the test species and T. nigrescens. Genotyping 432 individuals from 13 geographic populations revealed a comparatively higher genetic diversity in field populations. Partial isolation by distance and time was observed. Population bottlenecks were not detected, but recent expansion was evident in laboratory populations. Although five dominant genetic clusters were identified by Bayesian methods, meaningful hierarchical population structure was observed at between two and nine population groups (p < 0.01; 10,000 iterations). Biological control of the larger grain borer using T. nigrescens seems an important aspect of the sustainable integrated control approach of the pest. Ecological adaptations, appropriate release strategies and genetic diversity are all essential considerations in these efforts and could be responsible for the variable success already observed. There is some genetic differentiation between populations of T. nigrescens but, further studies would be necessary to ascertain the contribution of such diversity to its predatory performance. The effect of laboratory culturing in aggravating genetic drift should be accommodated to avoid loss of diversity during sampling, quarantine, rearing and release of the predator. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2009.
62

Genome-level studies on late maturity alpha amylase and boron tolerance in wheat

M.Carter@murdoch.edu.au, Meredith Diane Carter January 2006 (has links)
Under certain environmental conditions, some varieties of wheat synthesize the enzyme alpha amylase late in grain ripening, even in the absence of rain or sprouting. The resulting grain has a sound appearance but can be unsuitable for end-product applications due to the presence of late maturity alpha amylase (LMA) activity. Reduction of LMA and the development of cultivars tolerant to boron toxic soils are high priority traits in the WA wheat breeding program and the use of molecular markers closely linked to these traits for marker assisted selection (MAS) is highly desirable. The aims of this study were to take a genomics approach to provide detailed structural information for the region on wheat chromosome 7BL in which quantitative trait loci (QTLs) for LMA and boron tolerance (Bo1) have been mapped. Once the structure had been determined, this then laid the foundation for further studies to investigate the function of putative candidate genes identified within this region. The research involved the use of bioinformatic tools and rice/wheat synteny to investigate the structure of this chromosome region, followed by the use of molecular probes to isolate genomic DNA clones (BAC clones) corresponding to this region. A two-step bioinformatics strategy was used, involving (1) alignment of portions of the wheat and rice genomes, to identify rice genomic regions syntenic to wheat group 7L and (2) selection of candidate genes from those regions of the rice genome. The selected candidate genes included an anion transporter, as a candidate gene for boron tolerance, and GAMYB-like genes, as candidate genes for LMA. The GAMYB class of transcription factors identified were of particular interest because of published literature indicating its importance in controlling ƒÑ-amylase levels in cereal grains. The key phenotype of interest in this thesis is LMA and different levels of expression of ƒÑ-amylase are a key feature of this phenotype. Molecular markers and candidate genes were then used to screen two BAC libraries, one derived from the French cultivar, ¡¥Renan¡¦ and the other derived from Aegilops tauschii (the source of the D genome of wheat). About 300 BAC clones corresponding to the chromosome region of interest were obtained. Of these, 8 BAC clones (6 chosen through hybridization to a GAMYB-like probe, and 2 from wheat ESTs anchored to the rice genome) were selected for sequencing, allowing for the development of new microsatellite and single-nucleotide polymorphism (SNP) markers and for the discovery of novel transposable elements that provide a rich source of polymorphism for the development of additional markers. Novel microsatellite and SNP markers that were identified from the BAC clone sequence were mapped on the Cranbrook/Halberd doubled haploid (DH) mapping population. Markers were located to chromosomes 7AL, 7BL and 7DL. New markers derived from the BAC sequence information were used to anchor the BAC clones to the genetic map and develop a framework physical-genetic map. An automated annotation pipeline has been established and was used to annotate selected contigs of the sequenced BAC clones. A new marker assisted selection strategy, termed Multiplex Trait Signature (MuTs) analysis, was developed and tested on 39 wheat cultivars of known LMA phenotype. MuTs provides a graphical genotype of individuals for a particular chromosomal region and is a convenient tool for interrogating genetic similarity in the individuals surveyed. Based on assays of 22 markers (12 spanning the LMA QTL on chromosome 7BL and 10 spanning the LMA QTL on chromosome 3BS) on these 39 wheat cultivars, it was found that the varieties can be grouped according to pedigree and provides a tool for interpreting LMA status for a variety. Validation of the 7BL LMA and boron tolerance (Bo1) QTL regions was achieved using a targeted mapping approach using the doubled haploid population Pastor/RAC891 using published molecular markers and markers developed in this thesis. The main outcome of this study is that the genomic organisation of this region on chromosome 7BL is complex, and that the identification of candidate genes in wheat controlling 1) tolerance of cultivars to boron toxic soils and 2) pathways regulating the expression of LMA, is likely to involve the interplay of a network of regulatory genes.
63

Μοριακοί δείκτες στη σταδιοποίηση της λεμφαδενικής νόσου στον καρκίνο του προστάτη

Τορονίδης, Χαράλαμπος 06 September 2010 (has links)
Η αντιμετώπιση του καρκίνου του προστάτη (αλλά και των υπόλοιπων νεοπλασματικών νοσημάτων) δεν περιλαμβάνει απλώς την ανεύρεση νέων χημειοθεραπευτικών φαρμάκων. Αφορά και την κατοχύρωση ορισμένων δεικτών που μπορούν να μας δώσουν περισσότερες πληροφορίες για την ύπαρξη της νόσου, αλλά και του σταδίου εξέλιξης που βρίσκεται έτσι ώστε να παίρνονται οι πλέον σωστές αποφάσεις για την διαχείριση του ασθενούς. Η βιβλιογραφική αναφορά που ακολουθεί θα ασχοληθεί εκτενώς με αυτά τα ζητήματα (δηλ. τους δείκτες νόσου/σταδίου νόσου του καρκίνου του προστάτη) και ιδιαίτερα με μια υποομάδα αυτών: των μοριακών δεικτών της σταδιοποίησης της λεμφαδενικής νόσου στον καρκίνο του προστάτη. Αφορά μια πολλά υποσχόμενη μερίδα μοριακών δεικτών στην αντιμετώπιση της συγκεκριμένης νόσου που ενδέχεται να επηρεάσει και την προσέγγιση άλλων συμπαγών όγκων. / Use of new molecular markers for staging of lymph node disease in the prostate cancer.
64

Development of gene-linked molecular markers in South African abalone (Haliotis midae) using an in silico mining approach

Rhode, Clint 03 1900 (has links)
Thesis (MSc (Genetics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The South African abalone, Haliotis midae, is the only endemic species of commercial value. Aquaculture remains the only avenue for expanding the industry, since the closure of the fishery. The current focus is on implementing a molecular breeding programme; thus the development of molecular markers for linkage mapping and QTL analysis is a priority. Various markers, mainly anonymous, have been developed for H. midae; however emphasis is being placed on the development of gene-linked type I molecular markers. The present study investigates and demonstrates the use of public sequence collections to develop type I markers for a species with limited genomic resources, via three strategies: Surveying anonymous H. midae microsatellite markers’ flanking regions to find homology to gene sequences in public databases, cross-species marker transfer of anonymous markers from H. rubra and H. discus hannai demonstrating putative gene associations and lastly EST marker mining (SNP and microsatellites) from various Haliotids and testing transfer to the target species. Approximately 17% of H. midae anonymous markers showed significant similarity to genes. The current study also reports higher cross-species transferability from both H. rubra and H. discus hannai to H. midae (39% and 20.5%, respectively) than previously demonstrated and 15 EST-microsatellites and 16 EST-SNPs were successfully mined. Furthermore, the non-random distribution of microsatellites and high nucleotide diversity in the H. midae genome was confirmed. This is a low cost and time effective method for marker development and presents a continuous and dynamic resource that could be used for future marker development and characterisation as sequence information in public databases grow exponentially. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse perlemoen, Haliotis midae, is die enigste van vyf inheemse spesies van kommersiële waarde. Na die noodgedwonge sluiting van die vissery, is akwakultuur die mees praktiese oplossing om die perlemoen industrie uit te brei. Die huidige fokus is gerig op die implementering van ‘n molekulêre teel-program en dus is die ontwikkeling van molekulêre merkers vir genetiese kartering en kwantitatiewe kenmerk lokus analise, van uiterste belang. Tipe II merkers is voorheen vir die perlemoen ontwikkel, maar huidige tendense lê klem op die ontwikkeling van geen-gekoppelde tipe I merkers. Die huidige studie ondersoek die gebruik van publieke databasisse vir die ontwikkeling van tipe I molekulêre merkers vir ‘n spesie met beperkte genomiese bronne. Drie strategieë is geïmplementeer: Eerstens is ‘n opname gemaak van die homologie van perlemoen tipe II merker-vleuelende volgordes met geen volgordes in databasisse. Verder is die oordraagbaarheid van tipe II merkers vanaf H. rubra en H. discus hannai wat assosiasie met gene toon ondersoek. Laastens is ‘n Uitgedrukte Volgorde Merk (UVM) (Expressed Sequence Tag, EST) merker-ontginnings metode vanaf verskeie Haliotis spesies en toetsing van oordraagbaarheid na die teiken spesie uitgevoer. Ongeveer 17% van die tipe II H. midae merkers het geniese assosiasie getoon. ‘n Hoër tussen-spesie oordraagbaarheid vanaf beide H. rubra en H. discus hannai na H. midae (39% en 20.5%, onderskeidelik) word gerapporteer in vergelyking met vorige studies en 15 UVM-mikrosatelliete en 16 UVM-enkel nukleotied polimorfismes (single nucleotide polimorphism, SNP) is ontwikkel. Verder bevestig die studie die nie-lukrake verspreiding van mikrosatelliete en hoë nukleotied diversiteit in die perlemoen genoom. Die gebruik van publieke databasise vir die ontwikkeling en karakterisering van tipe I molekulêre merkers is tyd- en koste-besparend en bied ‘n volgehoue en dinamiese bron vir toekomstige gebruik.
65

Variabilidade genética entre e dentro de subpopulações de ipê-roxo Handroanthus Heptaphyllus (Vell.) Mattos e seu sistema reprodutivo

Mori, Neide Tomita [UNESP] 17 June 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-17Bitstream added on 2014-06-13T19:50:20Z : No. of bitstreams: 1 mori_nt_me_botfca.pdf: 988090 bytes, checksum: 61ea693b25f67c44cb9358042b0c2f9c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Handroanthus heptaphyllus (Vell.) Mattos, sinonímia Tabebuia heptaphylla ( Vell.) Toledo, popularmente conhecida por ipê-roxo, é uma espécie pertencente a família Bignoneaceae, muito apreciada pela sua beleza, madeira de excelente qualidade, além de algumas espécies dessa família possuírem substâncias as quais são usadas como produtos medicinais. A espécie é polinizada por abelhas, pássaros e outros visitantes que podem se alimentar das flores e dos frutos. Atualmente é utilizada em programas de reflorestamento de áreas degradadas, paisagismo e restauração. Ocorre em grande parte do Brasil, desde o Estado da Bahia até o Rio Grande do Sul, Minas Gerais, Mato Grosso do Sul, Santa Catarina e São Paulo, compreendendo as latitudes de 13ºS (BA) a 30ºS (RS). O trabalho teve como objetivos estudar a variabilidade genética entre e dentro das subpopulações de H. heptaphyllus, por meio de marcadores microssatélites e conhecer sobre o seu sistema reprodutivo. Para tanto, foram colhidas sementes de 30 árvores, na região de Botucatu, S.P., sendo grande parte na Fazenda Experimental Lageado pertencente a UNESP - Campus de Botucatu. As sementes foram semeadas no viveiro da UNESP e as folhas das mudas produzidas foram coletadas para a extração de DNA e posteriormente analisadas em géis de poliacrilamida. No total, foram estudados oito locos microssatélites polimórficos, que apresentaram desde seis alelos por loco (loco TAU22) a 14 alelos (locos TAU12, TAU30 e TAU31). A média de heterozigosidade esperada ( e H ˆ ) para as seis subpopulações foi de 0,732, sendo que a heterozigosidade observada ( o H ˆ ) foi de 0,618. Os índices médios de fixação variaram de -0,082 (subpopulação 4) a 0,255 (subpopulação 3), com média de 0,152. Os resultados das subpopulações estudadas mostraram os índices de fixação em níveis aceitáveis, com média de 15,2%, no entanto... / Handroanthus heptaphyllus (Vell.) Mattos, sinonímia Tabebuia heptaphylla (Velloso) Toledo, known as ipê-roxo, belongs to the Family Bignoniaceae. It is a very important Brazilian forest tree species because of its beautiful flowers, excellent wood quality, and medicinal properties. Its flowers are usually visited by animals, like bees, birds, bats, etc, for feeding and for pollination purposes. The species has also been used in programs of reforestation of degraded areas, landscaping, and restoration. The ipê-roxo is widespread throughout Brazil, from Bahia State to Rio Grande do Sul, Minas Gerais, Mato Grosso do Sul, Santa Catarina, and São Paulo States, from 13ºS (BA) to 30ºS (RS) latitudes. The research has as objectives to study the genetic diversity within and between subpopulations of H. heptaphyllus by microsatellite molecular markers and to understand its mating system. We collected seeds of 30 trees, through the Botucatu region, Brazil, mostly from the Lageado Experimental Station, São Paulo State University (UNESP) – Botucatu. The seeds were sown in a nursery and the leaves were collected, to extract the DNA, and analyzed through polyacrilamide gels. In a total of eight polymorphic microsatellite loci were analyzed that varied from six alleles (TAU22 locus) to 14 alleles (TAU12, TAU30, and TAU31 loci). The expected heterozygosity mean ( e H ˆ ) for the six subpopulations was 0.7318, the observed heterozygosity mean ( o H ˆ ) was 0.6183, and the average of fixation index (f) between pairs of the six population varied from -0,082 (subpopulation 4) to 0.255 (subpopulation 3), with an average of 0.152. The results of the studied subpopulations have shown acceptable levels of fixation index, presenting an average of 15.2%, therefore, the subpopulation 4 has shown a higher amount of heterozygous than expected. The total genetic diversity ( IT fˆ ) for the six subpopulations... (Complete abstract click electronic access below)
66

Variabilidade genética e estimativa da taxa de cruzamento do pinhão manso (Jatropha curcas L.) empregando marcadores moleculares / Genetic variability and estimation of outcrossing rate of physic nut (Jatropha curcas L.) using molecular markers

Eduardo de Andrade Bressan 27 January 2012 (has links)
O pinhão manso é uma pequena árvore tropical que adquiriu importância econômica pelo conteúdo de óleo em suas sementes e pela possibilidade de sua utilização para produção de biocombustível. As sementes e o óleo do pinhão manso são tóxicos devido principalmente à presença de ésteres de forbol, o que dificulta a sua utilização direta para o consumo humano e também dos resíduos para a alimentação animal. A falta de programas de melhoramento e cultivares comerciais e problemas com pragas e doenças estão desestimulando o cultivo do pinhão manso pelo mundo. Por se tratar de uma espécie semi-domesticada, a utilização de marcadores moleculares como ITS, PCR-RFLP, microssatélites e TRAP poderia auxiliar nos estudos de diversidade genética, visando o desenvolvimento de variedades adaptadas às necessidades dos agricultores. O objetivo deste estudo foi caracterizar a variabilidade genética de acessos de pinhão manso depositados no Banco de Germoplasma da Universidade Federal de São Carlos, além de possibilitar estudos sobre as relações entre as populações, centros de diversidade e determinar o sistema reprodutivo da espécie. Os resultados são discutidos destacando que a maior parte da diversidade encontra-se entre as populações estudadas. Os resultados derivados dos quatro marcadores utilizados corroboram que o centro de diversidade da espécie possivelmente está na América, com destaque para o México, Brasil e Colômbia. Os resultados apontam também para a diferenciação genética dos acessos atóxicos dos mexicanos quando comparados com os demais acessos tóxicos de pinhão manso. Os marcadores microssatélites desenvolvidos indicam que o pinhão manso apresenta um sistema misto de reprodução, combinando autofecundações, apomixia e cruzamento entre indivíduos aparentados, o que pode explicar a menor diversidade genética encontrada dentro das populações. Devido ao sistema misto de reprodução e aos acasalamentos correlacionados, a coleta de sementes de polinização aberta para fins de melhoramento ou conservação deve ser conduzida em um número de árvores acima de 100, visando garantir uma amostra estruturada / Physic nut (Jatropha curcas L.) is a tropical tree that has acquired economic importance for the content of oil in its seeds and the possibility of its use for biofuel production. However, oil seeds and physic nut are toxic because of the presence of secondary metabolites such as phorbol esters which makes its use directly for human consumption and also its waste for animal feed difficult. The lack of commercial varieties and problems with pests and diseases are making physic nut cultivation in the world unattractive. The use of molecular markers such as ITS, PCR-RFLP, microsatellites and TRAP can help in studies of genetic diversity, aimed at developing varieties adapted to farmers needs. The aim of this study was to characterize the genetic variability of physic nut accessions deposited in the Germplasm Bank of the \'Universidade Federal de São Carlos\', in addition to allowing studies on the relationship among accessions, centers of diversity and reproductive system. Results are discussed highlighting that most diversity is concentrated among populations. The four markers used indicated that the center of diversity of this species is probably in America with emphasis on Mexico, Brazil and Colombia. The microsatellite markers indicate that physic nut has a mixed system of reproduction, combining self-pollinations, apomixis and crossing between related individuals which may explain the small genetic diversity found within populations. Due to the mixed system of reproduction and correlated mating, the collection of open-pollinated seeds for plant breeding or conservation should be conducted in a number of trees above 100 in order to ensure a structured sample
67

Potvrzení výskytu \kur{Beauveria caledonica} v NP Šumava pomocí metod molekulárních markerů / Confirmation of \kur{Beauveria caledonica} occurence in Šumava National park by molecular markers

BINDER, Richard January 2015 (has links)
Biological plant protection against insect pests is an important alternative to chemical protection. One of the most important group used in the biological plant protection against insect pests are the entomopathogenic fungi. Entomopathogenic fungi are microscopic fungi that are able to induce a primary disease to insect pests. It is a very heterogeneous group of species. Worldwide there were isolated and described more than 750 species of entomopathogenic fungi. Genus Beauveria is considered one of the most important genera of entomopathogenic fungi. In the Czech Republic there has been confirmed species B. bassiana, B. brongniartii and now, on the basis of this work, B. caledonica. This study is aimed to confirm the occurrence of B. caledonica in National Park Šumava. To confirm this occurrence, I used analyzes based on the methods of molecular markers. Molecular markers are an indispensable part of science in the field of mycology, for example the strain characterization, population genetics, detection and identification of fungi, phylogenetic studies and evolutionary biology. For this study there were used sequence analysis of ITS, EF1- and LSU regions. The output data of these analyzes were used to create phylogenetic trees. The result of my thesis is taxonomical classification of studied isolates on species level.
68

Detekce skrytých přenašečů dědičné katarakty u psů pomocí PCR / PCR-based detection of hidden carriers of cataracts in dogs

FARKOVÁ, Barbora January 2015 (has links)
The hereditary cataract is one of the most common eye disease in dogs. The expansion of this disease in the Staffordshire bullterrier breed has been so massive that in the Czech Republic was introduced the rule of mandatory testing of at least one of a breeding pair. This is a degenerative disease of the lens causing total blindness of the affected animal within three years. Since some time ago there are no more dogs affected by the disease in the Czech Republic, there are however still hidden carriers which need to be discovered to the complete extinction of the disease in the genome. The goal of this study was to test simple ways of collecting biological samples, try them in practice and to verify whether they are suitable for the DNA isolation and also to test an alternative method of molecular detection of this disease. In total there have been 23 buccal swabs collected from male and female Staffordshire Bullterrier examples. The detection of the hidden carriers of the hereditary cataract was carried out by PCR analysis with specific primers. The obtained amplicons were detected by both gel and chip electrophoresis and by using fragment analysis. This detection of the carriers was based on the presence of two amplicons (heterozygotes). I came to conclusion that to detect hidden carriers it is neccessary to use the fragment analysis because of the difference of only one base in the reference section of DNA. Neither gel nor chip electrophoresis does provide sufficiently high resolution and it is not possible to detect two fragments that differ only by one bp. As the most appropriate sampling method I have chosen the buccal smear by cytological brush followed by isolating the DNA by Chelex with purification of the sample subsequently.
69

Caracterização de seqüências expressas do genoma café potencialmente relacionadas com a resistência a doenças / Caracterization of expressed sequences from coffee genome potentially related with the resistance to diseases

Alvarenga, Samuel Mazzinghy 16 July 2007 (has links)
Made available in DSpace on 2015-03-26T13:42:37Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1133771 bytes, checksum: 640defa7d0749c719bdf5d760421654a (MD5) Previous issue date: 2007-07-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Sequences potentially involved with the coffee resistance were identified, by in silico analyses, using information generated by the Projeto Brasileiro do Genoma Café (PBGC). For that, three strategies were used. Initially, keywords related to the plants resistance mechanism to pathogens were searched in scientific literature and used as drivers for data mining. Using the available tools at the PBGC bioinformatics platform, ESTs (Expressed Sequence Tags) related to each one of these words were identified. The search for similarities between some published sequences and sequences from the PBGC, by using the BLAST program was another strategy. The Electronic Northern, a tool developed by the Laboratório de Genômica e Expressão (LGE), was also used. Those strategies allowed the identification of 14,060 sequences of the PBGC. These sequences were similar to proteins known to be related to de plant disease defense process, for instance chitinase, kinase protein, cytochrome P450, disease resistance protein, pathogenesis related protein, LRR and NBS proteins, hypersensibility induced protein among others. The biological processes with witch these sequences are involved included metabolism, transport, transcription regulation, protein folding, biosynthesis and others. The ontology-based global analysis for molecular function showed that the genes are involved with metabolism, external stimulus response, cellular differentiation, nucleic acid binding, nucleotide binding, defense response, apoptosis and others. Aiming to verify the involvement of these sequences with the coffee tree resistance to leaf rust, 40 primers were designed to amplify the mined sequences. The primers were synthesized using the computational program Primer3 and their stability was tested by the program PrimerSelect. Different PCR conditions were tested. Using optimized reaction and amplification conditions, those 40 primers were tested in 12 resistant and 12 susceptible genotypes to Hemileia vastatrix, fungus that causes coffee leaf rust. Twenty nine of those resulted in unique and sharp bands, and only one of these was polymorphic. The 40 primers permitted to find one molecular marker polymorphic between the resistant and susceptible genotypes. This marker amplifies a region of the DNA which corresponds to a Coffea Arabica ORF for disease resistance protein. / Seqüências potencialmente envolvidas na resistência do cafeeiro a doenças foram identificadas, por meio de análise in silico, a partir das informações geradas pelo Projeto Brasileiro do Genoma Café (PBGC). Para isso foram usadas três estratégias. Inicialmente, palavras-chave correspondentes a termos relacionados aos mecanismos de resistência de plantas a patógenos foram identificadas na literatura e utilizadas como iscas para a mineração dos dados. Com o auxílio de ferramentas disponíveis na plataforma de bioinformática do PBGC, foram identificadas ESTs (Expressed Sequence Tags) relacionadas a cada uma destas palavras. Outra estratégia utilizada foi a busca por similaridades entre algumas seqüências públicas envolvidas com a resistência do cafeeiro a doenças com as seqüências do PBGC, por meio do programa BLAST. Utilizou-se, também, o Electronic Northern, uma ferramenta desenvolvida pelo Laboratório de Genômica e Expressão (LGE). A mineração, usando as três estratégias, identificou 14.060 seqüências do PBGC. Essas seqüências apresentaram similaridade com proteínas conhecidamente relacionadas com o processo de defesa da planta contra doenças como, por exemplo, quitinase, proteína quinase, citocromo P450, proteína de resistência a doenças, proteína relacionada com patogênese, proteínas com domínio LRR e NBS, proteínas induzidas por hipersensibilidade, entre outras. Os processos biológicos com os quais essas seqüências estão envolvidas incluíram metabolismo, transporte, regulação da transcrição, enovelamento de proteínas, biossíntese entre outros. A análise global baseada em ontologia de função molecular das seqüências obtidas mostrou que os genes estão envolvidos com metabolismo, resposta a estímulos externos, diferenciação celular, ligação a ácidos nucléicos, ligação a nucleotídeos, resposta de defesa, apoptose entre outras. Visando verificar o envolvimento destas seqüências com a resistência do cafeeiro à ferrugem foram desenhados 40 primers para amplificar algumas das seqüências mineradas. Os primers foram desenhados com o programa computacional Primer3 e a estabilidade desses foi verificada por meio do programa PrimerSelect. Diferentes concentrações dos componentes da reação de PCR foram analisadas. Utilizando as condições de reação e amplificação otimizadas, os 40 primers foram testados em 12 genótipos resistentes e 12 susceptíveis a Hemileia vastatrix, fungo causador da ferrugem. Vinte e nove destes 40 primers resultaram em bandas únicas e bem definidas, sendo um polimórfico. Este trabalho permitiu obter, até o momento, um marcador molecular polimórfico entre os indivíduos resistentes e susceptíveis. Esse marcador, denominado CARF 005, amplifica uma região do DNA que corresponde a uma ORF parcial de Coffea arabica que codifica uma proteína de resistência a doenças.
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Caracterização citogenética e molecular de três espécies de Gelasine (Iridaceae) ocorrentes no sul do Brasil : Gelasine elongata, G. coerulea e G. uruguaiensis

Focchezatto, Joana January 2015 (has links)
Gelasine Herb. (Tigridieae: Iridaceae) é composto por sete espécies nativas da América do Sul, sendo três delas encontradas no Rio Grande do Sul (Brasil): G. coerulea (Vell.) Ravenna, G. elongata (Graham) Ravenna e G. uruguaiensis Ravenna. São plantas bulbosas de folhas plicadas, flores perfeitas azuis ou roxas e compostas por dois conjuntos de tépalas desiguais. Gelasine elongata e G. coerulea encontram-se na lista de espécies ameaçadas para o RS, sendo a primeira delas ameaçada e a segunda criticamente ameaçada. Apesar de seu atual estado de vulnerabilidade, Gelasine é um gênero ainda pouco estudado, não havendo nenhuma informação quanto à variabilidade e diversidade genética. Os dados citogenéticos são também ainda escassos. Assim, a presente dissertação tem por objetivo caracterizar as três espécies de Gelasine ocorrentes no sul do Brasil quanto a aspectos moleculares, citogenéticos, além de compreender suas relações. Para a caracterização da diversidade genética foram usadas duas populações de G. coerulea e duas de G. elongata; não foi possível a utilização de G. uruguaiensis em função do número restrito de indivíduos. As amostras de DNA foram obtidas a partir de folhas das espécies mencionadas e empregada a técnica de ISSR (Inter Simple Sequence Repeat). Foram testados 44 primers para ISSR, destes, 12 apresentaram um bom padrão de amplificação que em conjunto geraram 91 loci. A quantidade de bandas por primer variou em média de 7,5. Este trabalho resultou em dados inéditos para o gênero Gelasine quanto à variabilidade genética inter e intra-populacional. Os resultados indicam que a variação genética intrapopulacional é muito baixa e que a maior diversidade encontrada para estas espécies ocorreu entre as populações. Não foi verificada correlação significativa com a distância geográfica entre as populações. Tais resultados indicam que o sistema reprodutivo, o método de dispersão de sementes e a presença de descendência clonal oriunda da divisão dos bulbos subterrâneos são fatores de grande influência na diversidade. Para caracterização citogenética das espécies foi empregada coloração convencional e bandeamento CMA/DAPI, e realizadas medidas cromossômicas. Foi também estimado o tamanho do genoma por citometria de fluxo a partir de folhas frescas das três espécies. As análises citogenéticas se mostraram bastante eficientes para a diferenciação das três espécies de Gelasine investigadas. Gelasine coerulea e G. uruguaiensis apresentam o mesmo número cromossômico básico e somático (2n = 2x = 14), não sendo encontrados citótipos poliploides. Ambas têm cariótipos relativamente simétricos, porém se mostram bastante distintas quanto ao tamanho dos cromossomos e seu padrão de bandeamento, com uma grande variação na ocorrência e distribuição de sequências de DNA repetitivo (bandas CMA/DAPI). O conteúdo de DNA também permite a clara diferenciação dessas espécies, tendo G. coerulea 2C = 11,30 pg e G. uruguaiensis 2C = 16,88 pg. Gelasine elongata possui número cromossômico básico diferente das anteriores (2n = 2x = 12) e cariótipo claramente bimodal. Os cromossomos têm menor tamanho, o que, consequentemente reflete no menor tamanho de genoma (2C = 3,45 pg). Além disso, o padrão de bandas CMA/DAPI é notadamente mais simples que das outras duas espécies, onde o maior par de cromossomos (par I) exibe as únicas bandas CMA+ presentes na região da constrição secundária. Os dados obtidos para G. elongata apontam para uma maior semelhança dessa espécie com outras duas do gênero Eleuthenine (2n = 2x = 12), o que reforça os dados filogenéticos existentes, onde G. elongata está separada de G. coerulea e agrupada no mesmo ramo de Eleutherine. Não foi observado heteromorfismo cromossômico para Gelasine elongata e nem para as outras duas espécies investigadas, embora tal situação tenha sido reportada para aquela espécie. Os dados obtidos para Gelasine com o uso dos fluorocromos CMA e DAPI, bem como os demais parâmetros citogenéticos investigados permitiram a clara diferenciação entre as espécies. Associados a uma abordagem filogenética, tais resultados auxiliam a compreensão das relações entre essas espécies e sua evolução. / Gelasine Herb. (Tigridieae: Iridaceae) comprises seven native species from South America, three of them are found in Rio Grande do Sul (Brasil): G. coerulea (Vell.) Ravenna, G. elongata (Graham) Ravenna and G. uruguaiensis Ravenna. These species are bulbous plants with plicate leaves and blue or violet perfect flowers which are composed of two unequal groups of tepals. Gelasine elongata and G. coerulea are included in the list of endangered species from RS, the first one is considered endangered and the latter, critically endangered. Notwithstanding its current vulnerability status, Gelasine is still a poorly studied genus and genetic variability and diversity information concerning its species are lacking. Cytogenetic data are also scarce. Thus the present dissertation aims to characterize the three Gelasine species occurring in Southern Brazil regarding its molecular and cytogenetic aspects in addition to understand their relationships. To characterize their genetic diversity, two populations of G. coerulea and two of G. elongata were used; it was not possible to investigate G. uruguaiensis due to its restricted number of individuals. DNA samples were obtained from leaves of the aforementioned species and ISSR (Inter Simple Sequence Repeat) technique was employed. Fourty-four ISSR primers were tested, 12 of these presented good amplification pattern which generated a total of 97 loci. The number of bands per primer had an average of 7.5. The present study resulted in novelty data for Gelasine concerning its inter and intrapopulation genetic variability. The results indicate a very low intrapopulation genetic variation and most of the diversity found in these species occurred among their populations. No significant correlation was verified between geographical distances of populations. Such results indicate that reproductive system, seed dispersal mechanisms and presence of clonal descendants generated from divisions of subterranean bulbs are factors that greatly influence in diversity. For cytogenetic characterization of the species, conventional staining and CMA/DAPI banding were employed and chromosome measurements were made. Also, genome size was estimated through flow cytometry using fresh leaves from the three species. Cytogenetic analyses were very efficient to differentiate all investigated species of Gelasine. Gelasine coerulea and G. uruguaiensis have the same basic and somatic chromosome number (2n = 2x = 14); polyploid cytotypes were not found. Both species display fairly symmetric karyotypes, however they are very distinct with respect to chromosome sizes and banding patterns, with a great variation in the occurrence and distribution of repetitive DNA sequences (CMA/DAPI bands). DNA content also allows clear differentiation of these species; G. coerulea has 2C = 11,30 pg and G. uruguaiensis has 2C = 16,88 pg. Gelasine elongata has a different base chromosome number than both former species (2n = 2x = 12) and a clearly bimodal karyotype. Its chromosomes are smaller which, consequently, reflects on the smaller genome size (2C = 3,45 pg). Furthermore, its CMA/DAPI band pattern is markedly simpler than the ones from the other two species, where the largest chromosome pair (pair I) contains the only CMA+ bands present in the secondary constriction region. Data obtained from G. elongata points out a larger resemblance between this species and two others belonging to Eleuthenine (2n = 2x = 12), which supports the phylogenetic data where G. elongata is separate from G. coerulea and groups with Eleutherine. Chromosome heteromorphism was not observed in Gelasine elongata nor in the two other investigated species, even though it had been reported for the first one. Data obtained from Gelasine with the use of CMA and DAPI fluorochromes, along with the other cytogenetic parameters investigated, allowed clear differentiation between species. Allied to a phylogenetic approach, these results can bring better understanding to the relations between these species and their evolution.

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