Ribonuklease P (RNaseP) ist eine essentielle Endonuklease, welche die 5'-Flanke von pre-tRNAs entfernt. In nahezu allen bisher untersuchten Organismen und Organellen besteht das Holoenzym aus einer RNA-Untereinheit und einer Protein-Komponente. Nur die Zusammensetzung des Enzyms in den Chloroplasten und Mitochochondrien mehrzelliger Eukaryonten scheint unklar. Eine RNA-Untereinheit konnte hier bis jetzt nicht nachgewiesen werden. Um den Aufbau der RNaseP aus photosynthetischen Organellen zu klären, wurde die RNaseP aus den Cyanellen von Cyanophora paradoxa untersucht. Das Enzym enthält eine RNA, welche im Gegensatz zu bakteriellen RNaseP-RNAs nicht in der Lage ist, die pre-tRNA-Prozessierung unter invitro-Bedingungen durchzuführen, obwohl sie eindeutig dem cy- anobakteriellen Strukturtyp zugeordnet werden kann. Die Cyanellen-RNaseP-RNA aus C.paradoxa kann mit rekombinanten cyanobakteriellen RNaseP-Proteinen zum katalytisch aktiven Holoenzym rekonstituiert werden. Das Einführen der hochkonservierten Nukleotide G22 und G213 in die Cyanellen-RNaseP-RNA führt nicht zu signifikanten Unterschieden im Prozessierungsverhalten des heterologen Holoenzyms. Durch Mutationsanalyse einer cyanobakteriellen RNaseP-RNA an den entsprechenden Positionen wurde gezeigt, dass diese Konsensus-Nukleotide keinen essentiellen Einfluss auf die Katalyse ausüben. Die funktionelle Charakterisierung der RNaseP-RNA aus den Cyanellen von G. nostochinearum bestätigt die Ergebnisse für C.paradoxa. Die RNA besitzt keine Ribozym-Aktivität und kann mit cyanobakteriellen RNaseP-Proteinen zum aktiven Holoenzym rekonstituiert werden. Um zu klären, ob die fehlende Ribozym-Aktivität der Cyanellen-RNaseP-RNAs auf das Fehlen der Fähigkeit zur Substratbindung zurückzuführen ist, wurden zirkular permutierte Cyanellen-RNase P-RNAs mit kovalent verknüpften pre-tRNAs konstruiert. Entsprechende Transkripte weisen keine Ribozymaktivität auf, können aber mit cyanobakteriellem RNaseP-Protein zum aktiven Komplex rekonstituiert werden. Die Reaktion läuft intramolekular, da die Prozessierungsreaktion mit zirkular permutierten Konstrukten nicht durch reife tRNAs gehemmt wird. Zur Identifizierung der Protein-Untereinheit(en) aus Cyanellen-RNaseP wurden polyklonale Antikörper gegen das rekombinate RNaseP-Protein aus dem Cyanobakterium Synechocystis PCC 6803 gewonnen. Immunoblots zeigen spezifische Signale im homologen und im Cyanellen-Extrakt, jedoch keinerlei Bindung des RNase P Proteins aus E. coli. Die hohe Spezifität der Antikörper für ein Cyanellen-RNase P-Protein konnte durch Immunopräzipitations-Experimente bestätigt werden. Da im vollständig sequenzierten Cyanellen-Genom keine zu RNaseP-Proteinen homologe Sequenz identifiziert werden kann, muss das Cyanellen RNaseP-Protein im Kern codiert sein. Um die Proteinkomponente der Cyanellen-RNase P zu klonieren, wurde eine cDNA-Expressionsbank für Cyanophora paradoxa angelegt. Versuche zum Immuno-Screening wurden aufgrund eines schlechten Signal:Hintergrund-Verhältnisses nicht weiter verfolgt. Durch Screening der cDNA-Expressionsbank mit Cyanellen-RNaseP-RNA konnten zwei Cyanophora-Proteine mit hoher Homologie zu eukaryontischen RNA-bindenden Proteinen identifiziert werden. Das Molekulargewicht des C.paradoxa-Holoenzyms wurde durch Ultrazentrifugation im Glyceringradienten zu etwa 280kD bestimmt. RNaseP-Aktivität und RNaseP-RNA-Untereinheit korrelieren im Gradienten mit einem 30kD-Protein, welches im Immunoblot mit cyanobakteriellen RNaseP-Protein-Antikörpern spezifisch erkannt wird. Das Cyanellen-Holoenzym zeigt in wesentlichen Merkmalen eine Übereinstimmung mit eukaryontischer RNaseP. Dennoch scheint die katalytische Aktivität in der RNA-Untereinheit lokalisiert zu sein, da die native, relativ große Cyanellen-Protein-Untereinheit ohne Funktionsverlust gegen sehr viel kleinere cyanobakterielle Protein-Untereinheiten ausgetauscht werden kann. Die Protein-Komponente der Cyanellen RNaseP scheint deshalb trotz ihrer Größenzunahme im Vergleich zu ihren evolutiven, bakteriellen Vorfahren, keine weiteren essentiellen Aufgaben übernommen zu haben. Eukaryontische RNaseP ist aus bis zu zehn Protein-Untereinheiten aufgebaut. Durch Genom-Analyse konnte in Arabidopsis thaliana das potentielle RNaseP-Protein Pop1 identifiziert werden. Mit der experimentell bestätigten Identität dieses Proteins wurde erstmals ein RNaseP-Protein aus A.thaliana eindeutig identifiziert. Durch spezifische Antikörper gegen dieses Protein kann RNaseP-Aktivität aus Weizen-Extrakt präzipitiert werden. / The essential tRNA-processing enzyme ribonucleaseP (RNaseP) is a striking example for evolution of an RNP enzyme. It is a ribonucleoprotein in bacteria, archea, and eukaryotic nuclei. No RNA component is found in mitochondria and chloroplasts of multicellular organisms to date, posing the question of enzyme evolution in these organelles of bacterial descent. The plastids (cyanelles) of some primitive algae, such as Cyanophora paradoxa and Glaucocystis nostochinearum, are intermediates in the evolution from cyanobacteria to chloroplasts and are an ideal model system to study the evolution of structure and function of RNaseP from organelles. C.paradoxa RNaseP has an essential RNA component which conforms to the bacterial consensus except for two highly conserved positions. The naked RNA has no ribozyme activity. Recombinant RNaseP-proteins from different cyanbacteria can form an active chimaeric holoenzyme with the catalytically inactive cyanelle RNaseP-RNA.Restoration of the bacterial consensus does not increase substrate turnover in the corresponding heterologous holoenzyme. Mutational analysis of cyanobacterial RNaseP-RNA ribozyme proved that these two consensus nucleotides have no essential influence on catalysis. The results for C.paradoxa RNaseP-RNA could be confirmed by analysis of G. nostochinearum RNaseP-RNA. This RNA can form an active holoenzyme with cyanobacterial RNaseP proteins, but shows no ribozyme activity either. To establish whether the lack of substrate binding ability is the reason for the missing ribozyme activity of cyanelle RNaseP-RNA, circularly permuted RNaseP-RNAs were designed in which the RNaseP-RNA is covalently linked to pre-tRNA substrates with variable flank lengths. Corresponding transcripts showed no ribozyme activity, but coudl be reconstituted with cyanobacterial protein. Cleavage of these tethered substrates is not inhibited by an excess of mature tRNAs, proving that it is an intramolecular reaction. To facilitate identification of cyanelle RNase P protein(s), polyclonal antibodies were generated against the recombinant cyanobacterial RNaseP-protein from the cyanobacterium Synechocystis PCC6803 Immunoblots show specific signals in homologous and cyanelle extracts, but no binding of E. coli RNase P protein. The high specificity of these antibodies is supported by immunoprecipitation of RNaseP activity from the same preparation. As no sequence similarity to bacterial-type RNaseP proteins can be identified in the cyanelle genome, this RNaseP protein must be encoded in the nucleus or is of a completely new type. With the aim of isolating the cyanelle RNaseP protein subunit, a C.paradoxa cDNA-expression-library was constructed. Due to a poor signal-to-background ratio, immuno-screening experiments were not embarked on. Screening the expression library using labelled cyanelle RNaseP-RNA resulted in cDNAs for two cyanelle proteins showing significant homology to eukaryotic RNA binding proteins. The molecular weight of the cyanelle holoenzyme was determinated to 280kD by ultrazentrifugation in glycerol gradients. RNaseP activity and the RNaseP-RNA subunit correlate with a 30kD-protein, which is specifically recognised in immunoblots by antibodies against cyanobacterial RNaseP protein. Although the overall composition of cyanelle RNaseP seems more similar to the eukaryote- than to the bacterial-type enzymes, the catalytic activity still seems to reside in the RNA subunit as the sizeable protein complement of the native cyanelle RNaseP can be functionally replaced by the much smaller cyanobacterial protein subunit. Therefore it can be concluded that the cyanelle protein subunit has not gained significant additional functions if compared to its bacterial ancestor. Eukaryotic nuclear RNaseP is composed of one RNA and up to ten protein subunits. Genomic analysis of A.thaliana revealed at least five protein subunits similar to those found in humans und yeast. Antibodies against the Pop1p-homolog from A.thaliana specifically recognize a single protein in a variety of plant species and can immunoprecipitate RNaseP activity from a wheat germ preparation. Thus, ATPOP1p is the first known RNaseP-protein of A.thaliana which has been verified by direct experimental evidence. The antibodies specific for this protein will facilitate the purification of RNaseP from wheat extracts.

In dieser Arbeit wird der Bau der (abzählbaren) abelschen p-Gruppen untersucht, durch die Betrachtung der dazugehörigen Quasibasen, die als bestimmte erzeugende Systeme der gegebenen p-Gruppe definiert sind. Die Untersuchung wird insbesondere auf die nichtseparablen p-Gruppen und ihre induktiven Quasibasen bezogen. / We describe (countable) p-groups by their relations relative to a quasibasis. In particular, non-separable p-groups will be examined.

Orientador: Paulo Cezar Ceresini / Resumo: Fungos do gênero Pyricularia apresentam uma ampla gama de plantas hospedeiras, com capacidade de infectar mais de 50 espécies de gramíneas nas quais causam a doença brusone. Há relatos que a espécies forrageira braquiária (Urochloa brizantha) é hospedeira de muitas espécies deste fungo. Muito embora a brusone em braquiária não cause prejuízos à produção de pastagens, a distribuição generalizada desta forrageira no país a torna uma importante fonte de inóculo do patógeno para diversas outras culturas de importância agrícola severamente danificadas pela brusone, em especial o trigo. A brusone do trigo é causada principalmente por Pyricularia graminis-tritici (Pygt), pode ser também ser atribuída a duas outras espécies de Pyricularia, P. pennisetigena (Pp) e P. urashimae (Pu). Dessa forma o objetivo deste estudo foi determinar a suscetibilidade bem como a reação de nove espécies e/ou cultivares do gênero Urochloa aos patógenos Pygt, Pp, Pu e P. grisea (Pg), a única espécie, até então, relatada como patógeno de braquiária no Brasil. De Pygt, foi avaliado também a virulência de sete raças do patógeno em espécies/cultivares de braquiária. Houve variação significativa na patogenicidade e na virulência e agressividade de espécies Pyricularia à diferentes espécies de Urochloa. As cultivares Ipypoã, BRS Tupi e Xaraés foram as mais resistentes às diferentes espécies Pygt, Pg, Pp e Pu do patógenos da brusone. Quando avaliamos a reação de Urochloa às raças B, C e D de P. graminis-tritici ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fungi of the genus Pyricularia have a wide range of host plants, and are capable of infecting more than 50 species of grasses in which they cause blast disease. There are reports that the signal grass forage species (Urochloa brizantha) is host to many species of this fungus. Although the blast disease in signal grass does not cause damage to pasture production, the widespread distribution of this forage in the country makes it an important source of pathogen inoculum for several other crops of agricultural importance severely damaged by blast, especially wheat. The wheat blast is caused mainly by Pyricularia graminis-tritici (Pygt), but it can also be associated with to two other species of Pyricularia, P. pennisetigena (Pp) and P. urashimae (Pu). Therefore, the objective of this study was to determine the susceptibility and the reaction of nine species and / or cultivars of the genus Urochloa to the pathogens Pygt, Pp, Pu and P. grisea (Pg), the only species hitherto reported as a pathogen of Urochloa in Brazil. For Pygt, the virulence of seven pathogen races or virulence groups to Urochloa species / cultivars was also evaluated. There was significant variation in the pathogenicity and virulence and aggressiveness of Pyricularia species to different Urochloa species. When we evaluated the reaction of Urochloa to P. graminis-tritici races B, C and D, the Urochloa species / cultivars tested showed susceptibility. However, resistance was detected for the other Pygt races. The ... (Complete abstract click electronic access below) / Mestre

Este trabalho descreve a síntese eletroquímica, a caracterização eletroquímica e estrutural e as propriedades ópticas dos filmes de poli(p−fenileno) (PPP), poli−3−metiltiofeno (P3MET), polipirrol (PPI) e dos derivados poli−p−fenileno−3−metiltiofeno (CP3MET) e poli−p−fenileno−pirrol (CPPI). Nossa motivação pode ser justificada pelo fato de o PPP e dos derivados serem polímeros conjugados eletroluminescentes na região do azul e importantes candidatos a serem empregados como camadas ativas em dispositivos emissores de luz (LEDs). Os filmes foram eletroquimicamente sintetizados sobre eletrodos de óxido de estanho dopado com flúor (FTO) em um meio não−aquoso de acetonitrila e perclorato de tetrabutilamônio. A resposta eletroquímica dos filmes de PPP, P3MET, PPI, CP3MET e CPPI foi investigada por voltametria cíclica em uma solução livre de monômeros, quando se verificou a formação de filmes eletroativos e estáveis eletroquimicamente. As propriedades ópticas dos filmes foram investigadas por espectroscopia de absorção in situ no UV−VIS, uma técnica amplamente usada para se estudar a estrutura eletrônica da maioria dos polímeros. Os espectros de UV−VIS dos filmes de PPP, P3MET, PPI, CP3MET e CPPI foram obtidos a diferentes potenciais, quando se verificou a ocorrência da transição π− π∗ dos filmes em seu estado neutro e a formação de estados polarônicos e bipolarônicos dos polímeros durante a sua oxidação. A caracterização estrutural dos filmes foi investigada por espectroscopia FT−Raman e FTIR, quando se verificou que o espectro dos filmes de CP3MET e CPPI, preparados por eletrooxidação de co−monômeros, apresentavam apenas as bandas características dos filmes dos homopolímeros, P3MET e PPI / This work describes the e1ectrochemical synthesis, structural and electrochemical characterization, and the optical properties of poly(p−phenylene) (PPP), poly(3−methylthiophene) (P3MET), polypyrrole (PPI) and their derivatives poly(p−phenylene−3−methylthiophene) (CP3MET) and poly(p−phenylene−pyrrole) (CPPI) films. Our motivation cab be justified by the fact that poly(p−phenylene) (PPP) and its derivatives are conjugated polymers that emit in the blue range of energy, and they appoint as potential candidates as active layers in displays (LEDs). The films were electrochemically synthesized on fluorine−tin−oxide glass (FTO) electrodes in a nonaqueous medium contend acetonitrile and TBAClO4. The electrochemical response of the PPP, P3MET, PPI, CP3MET and CPPI films were investigated by cyc1ic voltammetry in a monomer−free solution with the films showing a typical electroactive response. Their optical properties were investigated by in situ UV−VIS absorption spectroscopy, a technique widely used aiming at understanding the electronic structure of most polymers. The UV−VIS spectra of the PPP, P3MET, PPI, CP3MET and CPPI films were obtained at different p−doping states, i.e., at different applied potential allowing us to calculate the π− π∗ transition of the films at their neutral, and polaronic and bipolaronic states. The structural characterization of the films was investigated by FT−Raman and FTIR spectroscopy, where it was verified that the films prepared by the electrooxidation of co−monomers showed only the bands that were typical of those ones observed in the spectra of the homopolymers, P3MET and PPI.

The pyrimidine biosynthetic pathway is essential and similar in all bacteria. The pathway from Pseudomonas is regulated by nucleotides which bind to the upstream region of the pyrBC’ gene complex. Work in our lab mapped the genes and showed that the pyrB and pyrC’ were part of an overlap complex. The Pseudomonas aeruginosa has one circular chromosome. A former Pseudomonas now called Burkholderia cepacia is similar to P. aeruginosa except that it contains three circular chromosomes (CI, CII, CIII) and one large plasmid. The primary chromosome named CI contains the pyrBC’. To our knowledge there has been no report of the activity of ATCase in Pseudomonas and contrasted with that of Burkholderia. Here, we compare the activity of ATCase in P. aeruginosa and B .cepacia. Cells of both organisms were grown in Pseudomonas minimal medium and in Enriched medium. The ATCase was extracted and partially purified from each sample. It is hypothesized that the B. cepacia has greater activity for ATCase than do the Pseudomonas.

"Mycobacterium tuberculosis causes tuberculosis, one of the most life-threatening diseases of all time. It infects the host macrophages and survives in its phagosome. The host phagosome is a very hostile environment where M. tuberculosis copes with high concentration of transition metals (Zn2+, Cu2+), low levels of others (Mn2+, Fe2+) and acidic pH. P-ATPases are membrane proteins that transport various ions against their electrochemical gradients utilizing the energy of ATP hydrolysis. Based on their primary sequences; seven of the twelve mycobacterial ATPases are classified as putative heavy metal transporters and a K+-ATPase, while the substrate of four (CtpE, CtpF, CtpH and CtpI) remains unknown. Consistent with their membrane topology and conserved amino acids, CtpE and CtpF are possibly P2 or P3-ATPases that transport alkali metals or protons. We examined the cellular roles of orthologous CtpE and CtpF in M. smegmatis, a non-pathogenic model organism. We hypothesized that these novel P- ATPases play an important role in transporting alkali metals and/or protons. We analyzed growth fitness of strains carrying mutations of the coding gens of these enzymes, in presence of various metals and different pHs, as well as the gene expression levels under different stress conditions. We observed that the M. smegmatis mutant strains, lacking of CtpF or CtpE, are sensitive to high concentrations (mM) of Mn2+. Furthermore, CtpE mutant is sensitive to alkali pH. Our results indicate that CtpE and CtpF might be an Mn2+ or H+-ATPase that are required for cell’s homeostasis sustainability."

This thesis explores PhD-researcher oral presentations (OPs) in five studies on engagement and clarification strategies in a parallel corpus of 88 OP transcription-essay pairs (n=128228 tokens). Corpus and statistical significance procedures identify features that discriminate among researchers' levels of oral achievement and disciplines: gestural-verbal deixis, audience and impersonal identity projection, code glosses, and transformations of written into oral content. Features analyses include distribution across the levels and disciplines subcorpora, recurrent patterns, discourse functions, and pragmatic appropriacy and grammatical variety. The studies reveal that levels differ in the way that presenters mark stance authorship, anticipate the audience need for help, and vary their strategies grammatically. Disciplinary differences re-present the ways in which disciplines (re)produce knowledge. Hard-fields focus on research methods and outcomes is observed in interaction with images, academic identity projection, and technical terms explanation. Soft-field OPs focus on interpretations is observed in opinions towards existing knowledge and use of folk examples. Language choices also reflect the non-expert character of the audience. This thesis contributes to the study of oral academic genres by demonstrating the importance of multimodal, across modes, non-deficiency analyses; confirming disciplinary differences; and proposing ways of understanding levels of achievement based on pragmatic success rather than grammatical accuracy.

Despite the pervasive presence of linguistic impoliteness in many of Britain's most celebrated situation comedies, there has been little research on the relationship between impoliteness and humour in the sitcom. Likewise, while research has identified entertainment as an outcome of impoliteness, there has been little emphasis on humour. The present research explores the relationship between linguistic impoliteness and humour in 54 episodes of the BAFTA-winning British-Irish sitcoms Father Ted, Black Books and The IT Crowd (Channel4). In order to address earlier stylistic studies' over-reliance on researcher intuition in identifying humour, the study uses audience laughter as confirmation of successful humour uptake. Applying a triangulated impoliteness analysis using the frameworks of Spencer-Oatey (2000), Culpeper (2011) and Leech (2014), the study finds that impoliteness is prevalent in the sitcoms studied, with 151 impolite utterances per hour and an average of 2.5 impolite utterances per minute. Exploring the distribution of impoliteness strategies, the results show a clear preference for impoliteness that attacks freedom and personal qualities. Results also showed that character-led differences in impoliteness contribute to characterisation. Most importantly, the thesis finds a statistically significant relationship between utterances containing impoliteness and audience laughter responses, pointing to a relationship between impoliteness and humour.

The study of metaphor is an interdisciplinary endeavor crossing such fields as cognitive linguistics, psychology, and creativity studies. Two important conclusions on the nature of metaphor have been drawn to date: (1) the ability to use metaphor is a normal human cognitive ability and widespread in language; (2) metaphor is not a unitary construct and varies greatly from the highly familiar and conventional to the creative. Viewing metaphor as lying along a continuum, this thesis narrows the concept of metaphoric competence to creative metaphoric competence, which looks at this ability from a creativity perspective. In this thesis, it is hypothesized that creative metaphoric competence is an underlying competency, which is related to a more general creative competence, and therefore is projected onto both the L1 (Japanese) and L2 (English). In order to test this hypothesis, data from creative metaphor production tasks were collected in both languages. In addition, a number of creativity measurements were also developed with the aim of measuring the multifaceted nature of creativity. Relationships between these variables were investigated. Findings suggest that creative metaphoric competence is an individual difference variable, which could be described as a disposition towards novelty and is related to other measurements of creativity.

Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-08-09T16:27:05Z No. of bitstreams: 1 EduardoBorgesMilhomemDissertacao2016.pdf: 1205417 bytes, checksum: afc9b0c3f5e23392aeca9f6e745e55c0 (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-08-09T16:27:20Z (GMT) No. of bitstreams: 1 EduardoBorgesMilhomemDissertacao2016.pdf: 1205417 bytes, checksum: afc9b0c3f5e23392aeca9f6e745e55c0 (MD5) / Made available in DSpace on 2017-08-09T16:27:20Z (GMT). No. of bitstreams: 1 EduardoBorgesMilhomemDissertacao2016.pdf: 1205417 bytes, checksum: afc9b0c3f5e23392aeca9f6e745e55c0 (MD5) Previous issue date: 2016-09-24 / This paper approaches the legitimacy of the Public Prosecutor's Office to file civil actions in the public interest on tax matters. Regarding such theme, the first subject to be addressed herein shall be the prohibition contained in sole paragraph of Article 1 of the Public Interest Civil Action Act, which prohibits the use of such instrument in claims involving taxes. Such rule, when confronted with the constitutional principle of non-obviation of jurisdiction, in its collective dimension, is deemed as unconstitutional in this paper, because, in such case, a collision of fundamental rights capable of justifying such a restriction of access to the collective action, could not be verified. Along with the legal issue, this research analyzes the precedents of the Supreme Federal Court on the subject, once it was verified that, already in the systematization of general repercussion, the court denied the legitimacy of the Public Prosecutor's Office to file civil actions in the public interest in favor of taxpayers, whereas such actions were admitted when the participation of the Public Prosecutor's Office was in favor of tax authorities. It turns out that after confronting such decision with the specialized doctrine, including previous precedents of the Supreme Federal Court itself, it appears that none of the commands, i.e., the one lacking standing (in the case of actions in favor of taxpayers), and the one with standing (in the case of defense of the tax authorities) should be regarded in a restrictive way, as if worthy of being relativized, because it is necessary to verify, in a concrete case, if there is social interest capable of supporting the legitimacy of the Public Prosecutor's Office. In the case of actions defending taxpayers, such social interest can be demonstrated both by the social dimension inherent to the majority of tax relations and by the broad scope of the claim discussed herein, or even by the taxpayers??? condition. Regarding the demands in favor of tax authorities, although the conclusion is similar, it is more restrictive considering that the legitimacy of the Public Prosecutor's Office shall be characterized only when there is evidence of the existence of primary public interest justifying the actions of the ???parquet???. / O trabalho versa sobre a legitimidade do Minist??rio P??blico para propor a????o civil p??blica em mat??ria tribut??ria. Para avan??ar em tal tem??tica, aborda-se, inicialmente, a veda????o contida no par??grafo ??nico do artigo 1?? da Lei da A????o Civil P??blica, que pro??be a utiliza????o do instrumento em pretens??es que envolvam tributos. Regra esta que, ao ser confrontada com o princ??pio constitucional da inafastabilidade de jurisdi????o em sua dimens??o coletiva, ?? considerada inconstitucional neste estudo. Isso porque n??o se verifica na hip??tese uma colis??o de direitos fundamentais apta a justificar tal restri????o de acesso ao processo coletivo. Al??m da quest??o legal, a presente pesquisa analisa a jurisprud??ncia do Supremo Tribunal Federal sobre o assunto, verificando-se que a corte, j?? na sistem??tica da repercuss??o geral, negou a legitimidade do Minist??rio P??blico para propor a????o civil p??blica em favor do contribuinte ao passo que admitiu tais a????es quando a atua????o do Minist??rio P??blico for em favor do Estado. Ocorre que, ap??s confrontar tais julgados com a doutrina especializada e inclusive com precedentes do pr??prio supremo, constata-se que tais comandos, de ilegitimidade (no caso de a????es em favor do contribuinte) e de legitimidade (no caso de defesa da Fazenda P??blica), n??o devem ser vistos de forma taxativa, merecendo relativiza????es. Isso porque ?? necess??ria uma verifica????o se, no caso concreto, existe interesse social apto a fundamentar a legitimidade do Minist??rio P??blico. No caso das a????es em defesa do contribuinte, esse interesse social pode ser demonstrado tanto pela dimens??o social inata ?? maioria das rela????es tribut??rias, como pelo largo alcance da pretens??o discutida, ou ainda, pela condi????o dos contribuintes. Com rela????o ??s demandas em favor do Patrim??nio P??blico, a conclus??o ?? semelhante, todavia, mais restritiva, tendo em vista que a legitimidade do Minist??rio P??blico ficar?? caracterizada somente quando se evidenciar a exist??ncia de interesse p??blico prim??rio que justifique a atua????o do parquet.