The Guiana Shield is a sub-region of Amazonia, one of the richest areas on earth in terms of species number. It is also one of the most pristine areas and is still largely unexplored. Species number, distribution, boundaries and their evolutionary histories remain at least unclear but most of the time largely unknown. This is the case for most Anurans, a group which is recognized as threatened globally and is disappearing even from pristine tropical forests. Given the pace of forest destruction and the growing concerns about climate change it is urgently necessary to obtain a better estimate of regional biodiversity in Amazonian frogs as well as a better understanding of the origin and distribution of Anuran diversity. Furthermore, given their sensitivity to climatic conditions, amphibians are a good model to investigate the influence of paleoclimatic events on Neotropical diversification which was supposedly the driving force on biotic evolution during Pleistocene in the Guiana Shield. I first test species boundaries in two species Scinax ruber and Rhinella margaritifera. These species are widely distributed, abundant and largely recognized as species complexes. I used an original species delineation method based on the combined use of mitochondrial and nuclear DNA in phylogenetic and phylogeographic analyses. Phylogenetic analyses demonstrated the polyphyly of Scinax ruber and Rhinella margaritifera. These species consist of multiple lineages that may all merit species status. Conflicting signals of mitochondrial and nuclear markers indicated the possibility of ongoing hybridization processes. Phylogeographic analyses added further information in support of the specific status of these lineages. Our results highlight the utility of combining phylogenetic and phylogeographic methods, as well as the use of both mitochondrial and nuclear markers within one study. This approach helped to better understand the evolutionary history of taxonomically complex groups of species. The assessment of the geographic distribution of genetic diversity in tropical amphibian communities can lead to conclusions that differ strongly from prior analyses based on the occurrence of currently recognized species alone. Such studies, therefore, hold the potential to contribute to a more objective assessment of amphibian conservation priorities in tropical areas. Subsequently, I tested if these first results on cryptic species are generalisable, questioning what would potentially be a minimum estimate of the number of cryptic frog species in Amazonia and the Guiana Shield, using mtDNA with multiple complementary approaches. I also combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs. In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contra to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher genetic distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species. Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas. As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised. The Rhinella margaritifera complex is characterisized by the presence of many cryptic species throughout its wide distribution, ranging from Panama to Bolivia and almost entire Amazonia. French Guiana has long been thought to harbor two species of this group, though molecular data analysed in previous chapters indicated as many as five lineages. I tested whether morphological measurements are correlated or not with genetic data using discriminant analysis and if diagnostic characteristics among the previously determined lineages can be used to describe these new species. This is a novel integrative method which can lead to a facilitation of the description of cryptic species that have been detected by phylogenetic and/or phylogeographic studies. These analyses, combined with published data of other Rhinella species, indicated that two of these lineages represent previously unnamed species. Two of the remaining are allocable to R. margaritifera while the status of the fifth is still unclear because so far it is morphologically indistinguishable from R. castaneotica. Determining if codistributed species responded to climate change in an independent or concerted manner is a basic objective of comparative phylogeography. Species boundaries, histories, ecologies and their geographical ranges are still to be explored in the Guiana Shield. According to the refugia hypothesis this region was supposed to host a forest refugium during climatic oscillations of the Pleistocene but the causes and timing for this have been criticized. We investigated patterns of genetic structure within 18 frog species in the eastern Guiana Shield to explore species boundaries and their evolutionary history. We used mtDNA and nuclear DNA and complementary methods to compare the genetic diversity spatially and temporally. With one exception all the species studied diversified repeatedly within the eastern Guiana Shield during the last 4 million years. Instead of one Pleistocene forest refugium the Guiana Shield has probably hosted multiple refugia during late Pliocene and Pleistocene. Most of these Pleistocene refugia were probably situated on the coast of French Guiana, Amapà, Suriname and Guyana. This diversification likely resulted from forest fragmentation. Many species deserve taxonomic revisions and their ranges to be reconsidered. The local endemism of the Anuran fauna of the Guiana Shield is likely to be much higher and some areas consequently deserve more conservation efforts. Specifically I questioned whether major intraspecific diversification started before the Pleistocene and occurred within the Guiana Shield or ex situ. According to ecological characteristics of the species involved I will test different diversification hypotheses. The consequences on the diversity and the endemism of the Guiana Shield will be explored. My results demonstrate that we have been grossly underestimating local biological diversity in the Guiana Shield but also in Amazonia in general. The order of magnitude for potential species richness means that the eastern Guiana Shield hosts one of the richest frog fauna on earth. In most of the species studied high levels of mtDNA differentiation between populations call for a reassessment of the taxonomic status of what is being recognised as single species. Most species display deep divergence between eastern Guiana Shield populations and Amazonian ones. This emphasizes that the local endemism in the Guiana Shield of these zones is higher than previously recognized and must be prioritised elements taken into account in conservation planning. Nevertheless, a few other species appear widely distributed showing that widespread species do exist. This underlines the fact that some species have efficient dispersal abilities and that the frog fauna of the eastern Guiana Shield is a mixture of old Guianan endemic lineages that diversified in situ mostly during late Pliocene and Pleistocene and more recently exchanged lineages with the rest of Amazonia. Recognizing this strong historical component is necessary and timely for local conservation as these zones are likely to be irremediably modified in the near future.

Green algae are quite important primary producers in fresh waters. The genus Chlorella represents one of algae most frequently utilized in algal biotechnologies to produce biomass, using either autotrophic or heterotrophic cultivation systems. It is than exploited as a food supplement for humans or animals. However, particular species within the genus are morphologically indistinguishable and molecular markers should be used to characterize production strains. This work is aimed to molecularly characterize three production strains of Chlorella for patent protection purposes and to specify their phylogenetic and taxonomic position.

We can find a lot of microorganisms living in snow including psychrophilic snow algae from the order Chlamydomonadales (Chlorophyta). They are adapted to the extreme conditions in this habitat and can cause the phenomenon of coloured snow. The species Chlamydomonas nivalis (Bauer) Wille is the most commonly associated with red snow in alpine and polar regions during summer season worldwide. In the field material, we can find red spherical cells without flagella and any morphological characteristics suitable for species determination. Until now, this species has not been isolated into laboratory culture and its life cycle is unclear. Furthermore it has been shown that red coloured snow can be caused by more species which used to be determined as Chlamydomonas nivalis. The aim of this study was to collect samples of red snow from different parts of Europe, to describe the morphological variability of Chlamydomonas nivalis-like snow algae in relation to region of origin, to try to isolate laboratory strain of this species and to describe its position and distribution by phylogenetic analysis of laboratory strains and field samples. Red snow samples were collected from 30 European localities in Slovenian Alps, Romania, Dolomites, Ötztal, Wallis and Sarntal Alps, High Tauern, Ortler massif, in Norway,...

The molecular biology revolution of the 1960s has given rise to an enormous body of literature describing, in great detail, the inner workings of the cell. Over the course of the past 50 years, and countless hours at the bench, biologists have used the implications of basic research to produce vaccines, antibiotics, and other therapies that have improved both the quality and duration of our lives. Despite these incredible advances, basic questions remain unanswered. In even the simplest model organism, hundreds of essential genes have never been studied. Moreover, the central dogma of molecular biology—DNA to RNA to Protein—is understood largely in terms of how the cell functions under ideal conditions. What happens when things go wrong? This study seeks to characterize one of the cell’s contingency plans—a quality control measure for the eukaryotic ribosome. Today, despite the abundance of ribosomes in all cells, we are only beginning to understand the details of how they function, and the mechanisms that monitor their behavior. Recently, inactivated ribosomes were shown to be destroyed by the cell's own quality control measures, potentially preventing them from harming the cell. This system, dubbed 18S Nonfunctional rRNA Decay, is known to utilize a pair of ribosome-binding proteins to carry out its function. Yet the pathway still functions, albeit more slowly, in the absence of these two proteins, suggesting that other components must exist. The work discussed here is largely concerned with identifying these other factors, characterizing their activities, and determining how the 18S Nonfunctional rRNA Decay pathway impacts the health of the cell.

No description available.

Det har forskats mycket på olika signalvägar i det mänskliga genomet, trotts detta finns det många frågetecken som kvarstår. Denna uppsats undersöker några av dem. Syfte: Undersöka förändringar i genuttryck och mRNA-nivåer för hypertrofi- (MRF4) translations- (5.8S & 18S) och proteolysreglerande gener (MuRF1 & GDF-8) efter en 10 veckor lång styrketräningsperiod hos kvinnor och män. Frågeställningar: (1) Finns det en förändring i total mängd RNA före och efter en 10 veckors styrketräningsintervention. (2) Finns det en förändring i uttryck av MRF4, 5.8S, 18S, MuRF1 samt GDF-8 efter en 10 veckors styrketräningsintervention. (3) Finns det en könsskillnad i förändringen av total mängd RNA samt aktivering av MRF4, 5.8S, 18S, MuRF1 och GDF-8 efter en 10 veckors styrketräningsintervention. Metod: Urvalet för analysen bestod av 16 otränade försökspersoner varav 8 var män och 8 var kvinnor. Försökspersonerna utförde unilateral styrketräning av nedre extremiteten under 10 veckor, under 2 av dessa veckor utfördes ocklusionsträning.  Träningsperiodiseringen var vågformig (70-90% av 1RM, 5-12 rep, 3 ggr/vecka). Muskelbiopsier togs i det arbetande benet före träningsperiodens start samt 3-7 dagar efter träningsperiodens avslut. Genuttryck analyserades med qPCR. Resultat: Det fanns ingen signifikant skillnad i förändring mellan män och kvinnors totala RNA eller genuttryck. Total RNA ökade signifikant (p<0,01) med 19,2 %. Kvinnorna hade en signifikant ökning (P<0,05) av RNA på 27,6 % medan männen hade en signifikant ökning (p<0,05) på 14 %. MRF4 hade en signifikant (P>0,05) procentuell ökning i genuttryck med 55,7 % och kvinnor för sig hade en signifikant (P>0,05) ökning på 64 %. GDF-8 ökade signifikant (P>0,05) med 55,5 % medan GAPDH ökade signifikant (P>0,05) för båda könen tillsammans med 70,6 % och för män med 87,8 %. MuRF1 och 5.8S hade inga signifikanta förändringar i genuttryck. Slutsats: Det verkar som att både män och kvinnor får en liknande procentuell förändring av total RNA och mRNA genuttryck 3-7 dagar efter en 10 veckors hypertrofistyrd styrketräningsperiod. För att mäta genuttryck av translationsgenen MRF4 verkar 3-7 dagar efter en 10 veckors styrketräningsperiod vara en tidpunkt då det fortfarande pågår hypertrofi av skelettmuskulaturen.  Av de proteolysreglerande generna GDF-8 och MuRF1 sågs en uppreglering av GDF-8 vilket skulle kunna vara ett tecken på att hypertrofin börjar hämmas. Ett oväntat fynd var att GAPDH visade sig vara olämplig som kontrollgen vid en styrketräningsintervention på 10 veckor och att 18S var väldigt stabil. Detta kan betyda att GAPDH inte skall användas vid längre styrketräningsinterventioner. / There have been much research on signaling pathways in the human genome, but there still remain many questions. This paper examines some of them. Aim: Investigate changes in gene expression and mRNA levels of hypertrophy (MRF4), translation (5.8S & 18S) and proteolysis regulating genes (GDF-8) after a 10-week strength training period in men and women. Research questions: (1) Is there a change in the total amount of RNA before and after a 10-week strength training intervention. (2) Is there a change in the expression of MRF4, 5.8S, 18S, Murf1 and GDF-8 after 10 weeks of strength training. (3) Is there a gender difference in the change of total RNA and the expression of MRF4, 5.8S, Murf1 and GDF-8 after a 10-week long strength training intervention. Method: The sample for analysis consisted of 16 untrained subjects, of whom 8 were men and 8 were women. The subjects performed unilateral resistance training of lower extremities for 10 weeks, during two of these weeks blood flow restriction training were performed. The training was undulating (70-90% of 1RM, 5-12 cord, 3 times / week). Muscle biopsies were taken from the working leg before the start and 3-7 days after the training period. Gene expression was analyzed by qPCR. Results: There was no significant gender difference in total RNA or gene expression. Total RNA was significantly increased (p <0.01) with 19.2 %. The women had a significant increase (P <0.05) of RNA at 27.6 %, while the men had a significant increase (p <0.05) at 14 %. MRF4 had a significant (P> 0.05) percentage increase in gene expression by 55.7 %, and women had a significant (P> 0.05) increase of 64 %. GDF-8 increased significantly (P> 0.05) with 55.5 %, while GAPDH increased significantly (P> 0.05) for both sexes with 70.6 % and for men with 87.8 %. Murf1 and 5.8S had no significant changes in gene expression. Conclusions: It seems that both men and women experience a similar percentage difference of total RNA and mRNA gene expression 3-7 days after a 10 weeks long strength training period. To measure the gene expression of MRF4 3-7 days after a 10-week weight-training period seems to be a time when there still is a anabolic responses in the skeletal muscle. Of the proteolysis regulating genes GDF-8 and Murf1 there was an upregulation of GDF-8, which could be a sign that the inhibition of hypertrophy started. An unexpected finding is that GAPDH was found to be unsuitable as a control gene at a strength training intervention at 10 weeks and rRNA 18S was very stable, which could mean that GAPDH should not be used as control gene in longer strength training studies.

The aim of this diploma thesis was to reveal the taxonomic position and phylogenetic relationships of the dominant planktonic algae in two acid metal-rich lakes (Hromnice Lake and Plešné Lake, Czech Republic) and to compare these isolates with other closely related strains with the focus on the tolerance to various toxic metals (Cr, Al, Cu, Mn, Zn, Hg). The phylogenetic analyses showed that both strains belong to species Coccomyxa simplex. It was the first evidence that specifically this species is capable to become the dominant phytoplankton alga in the extreme environment of acid lakes with increased supply of phosphorus. Based on 18S rDNA analysis, four independent phylogenetic lineages were revealed within the genus Coccomyxa with three of them containing isolates from acid freshwaters. Furthermore, new strains of the recently described species Coccomyxa polymorpha were found growing in various chemical solutions. The toxicity test revealed that Coccomyxa simplex strains isolated from Hromnice and Plešné lakes did not show any peculiar resistance to increased metal concentrations. A significantly strain-specific response was recorded in case of aluminum, however, it was not related to the concentration of this metal in the original habitat. The ability to thrive in extreme habitats is probably...

Cryptococcus neoformans (C. neoformans), um fungo que se encontra disseminado em várias partes do mundo, inclusive no Brasil, é o responsável pela criptococose infecção oportunista mais comum em pacientes com a síndrome da imunodeficiência adquirida (SIDA). O caráter sistêmico da criptococose pode levar esses pacientes a óbito. A finalidade de se obter um diagnóstico laboratorial rápido e acurado de C. neoformans, principalmente para o seguimento dos pacientes HIV nos levou a investigar \"seqüências iniciadoras\" (Si) A, B e C das regiões 18SrDNA, 5,8SrDNA e ITS do Cryptococcus spp. Pela Nested PCR com estas seqüências, sugerimos a melhor delas para o desenvolvimento de um diagnóstico molecular em relação aos métodos usuais. Para tal, foram avaliadas amostras de soro e líquor de 39 pacientes, que já haviam recebido tratamento clínico. Todos os casos foram selecionados em grupos, como segue:7 com criptococose (GIII), 14 HIV positivos (GIV), 18 HIV positivos associados com a criptococose (GV) em relação a 10 controles - indivíduos sadios (GI) e amostras de culturas referência (GII). Os resultados obtidos pela Nested PCR com as \"Sis\" A, B e C foram comparados àqueles obtidos pelos métodos de diagnóstico convencionais. As análises desse estudo mostraram que as \"Sis\" A, B e C detectam C. neoformans com especificidade variada, tanto no soro (SiA 91,66%, SiB-100%, SiC 75%), como no líquor (SiA 83,33%, SiB 100% e SiC 75%) mas não apresentaram falso positivo, quando esses resultados foram comparados aos obtidos das culturas heterólogas (GVI). A SiB, em líquor, apresentou sensibilidade, acurácia, valores preditivo positivo e negativo, e especificidade de 100% para a detecção de C. neoformans da mesma forma que no soro, porém neste o valor preditivo negativo foi 89%, acurácia 94% e a sensibilidade 88%. Em amostras de soro e líquor, os testes Tinta da China e Látex, mostraram resultados falso positivos para o GIV e falso negativos nos grupos GIII e GV. As análises comparativas entre as técnicas mostraram que a ordem de eficiência da sensibilidade para detecção de C. neoformans no soro foi SiB>SiA=Látex>SiC e no líquor foi SiB> SiA>tinta da China>Látex=SiC. No soro, a especificidade entre as técnicas foi SiB>SiA=Látex>SiC e no líquor foi SiB=tinta da China>Látex>SiA>SiC. De acordo com nossos dados, concluímos que, independente da doença associada (HIV) ou se o paciente for tratado, a SiB foi a melhor seqüência para a detecção de C. neoformans, tanto em amostras diretamente de soro, como de líquor para todos os grupos estudados. Tendo em vista os fatos, acreditamos que, a aplicação da técnica da Nested PCR com a \"SiB\", em amostras de líquor e soro, é um método viável e acurado para realizar o diagnóstico molecular do C. neoformans em pacientes HIV. O uso de amostras de soro, para o segmento dos pacientes com SIDA, durante o tratamento, pode ser a forma menos invasiva em relação ao líquor para a detecção do C. neoformans, com vantagens sobre os métodos utilizados / Cryptococcus neoformans (C. neoformans), a fungus that is widespread in many parts of the world, including Brazil, is responsible for cryptococcosis the most common opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). The systemic character of cryptococcosis may be fatal. In order to obtain a rapid and accurate laboratory diagnosis to follow - up of HIV-cryptococcosis patients led us to investigate the sensibility and especificity of three primers (A, B and C) of 18SrDNA, 5,8SrDNA and ITS regions of Cryptococcus spp. Using Nested PCR with those primers we suggest the best among them to be used as a method of molecular diagnosis in relation to the usual techniques. For this purpose, the serum and cerebrospinal fluid (CSF) of 39 patients, who had received medical treatment, were evaluated. All cases were separated in groups, as follows: 7 with cryptococcosis (group III), 14 HIV positive (group IV), 18 HIV positive associated with cryptococcosis (group V) were compared to, 10 healthy subjects (group I) controls, as well as to reference cultures (group II) samples. The results obtained by nested PCR with primers A and B and C were compared to those obtained by conventional diagnostic methods. The analyses of primers A, B and C detected C. neoformans both in serum (SiA 91,6%, SiB-100%, SiC 75%), and in CSF (SiA 83,3%, SiB 100% e SiC 75%). Besides, they were specific for the identification of C. neoformans and showed that there were no false positives when compared with heterologous cultures (group VI) samples. The primer B in CSF showed 100% sensitivity, 100% accuracy and 100% predictive values (positive and negative), and 100% specificity for the detection of C. neoformans, the same that occurs in serum, but in this case, with 88% in sensitivity, 89% predictive value negative and 94% accuracy. In serum and CSF samples the China Ink and the Latex tests showed false positive results for group IV and false negative for III and V groups. The comparative analysis among the techniques (Nested PCR, China Ink, Latex) indicated that the efficiency order of sensitivity for the detection of C. neoformans were PrB> PrA = Latex> PrC in serum and PrB > PrA > China Ink> Latex = PrC in CSF. For the serum and CSF specificities the same techniques were used with the following results: PrB>PrA=Latex>PrC and PrB=China Ink>Latex>PrA>PrC. According to our data we conclude that, whether the patients had been under treatment or not, the Nested PCR by PrB was the best way to detect C. neoformans both in serum and in CSF for all groups. The following up of AIDS patients, throughout the course of therapy was found to be feasible, accurate and less invasive to detect C. neoformans by using serum samples (directly)

This thesis reviews knowledge about diversity of blood parasites of fish. Blood smears of fish used in this study were obtained in Billefjorden (Svalbard archipelago, Arctic). Desseria myoxocephali, the type species of Desseria, is the only one parasite that was found in the smears. A partial 18S rDNA sequence of D. myoxocephali was prepared and phylogenetic analyses were computed. D. myoxocephali forms a lineage together with Dactylosoma ranarum and Babesiosoma stableri within adeleorinid clade.

Cryptococcus neoformans (C. neoformans), um fungo que se encontra disseminado em várias partes do mundo, inclusive no Brasil, é o responsável pela criptococose infecção oportunista mais comum em pacientes com a síndrome da imunodeficiência adquirida (SIDA). O caráter sistêmico da criptococose pode levar esses pacientes a óbito. A finalidade de se obter um diagnóstico laboratorial rápido e acurado de C. neoformans, principalmente para o seguimento dos pacientes HIV nos levou a investigar \"seqüências iniciadoras\" (Si) A, B e C das regiões 18SrDNA, 5,8SrDNA e ITS do Cryptococcus spp. Pela Nested PCR com estas seqüências, sugerimos a melhor delas para o desenvolvimento de um diagnóstico molecular em relação aos métodos usuais. Para tal, foram avaliadas amostras de soro e líquor de 39 pacientes, que já haviam recebido tratamento clínico. Todos os casos foram selecionados em grupos, como segue:7 com criptococose (GIII), 14 HIV positivos (GIV), 18 HIV positivos associados com a criptococose (GV) em relação a 10 controles - indivíduos sadios (GI) e amostras de culturas referência (GII). Os resultados obtidos pela Nested PCR com as \"Sis\" A, B e C foram comparados àqueles obtidos pelos métodos de diagnóstico convencionais. As análises desse estudo mostraram que as \"Sis\" A, B e C detectam C. neoformans com especificidade variada, tanto no soro (SiA 91,66%, SiB-100%, SiC 75%), como no líquor (SiA 83,33%, SiB 100% e SiC 75%) mas não apresentaram falso positivo, quando esses resultados foram comparados aos obtidos das culturas heterólogas (GVI). A SiB, em líquor, apresentou sensibilidade, acurácia, valores preditivo positivo e negativo, e especificidade de 100% para a detecção de C. neoformans da mesma forma que no soro, porém neste o valor preditivo negativo foi 89%, acurácia 94% e a sensibilidade 88%. Em amostras de soro e líquor, os testes Tinta da China e Látex, mostraram resultados falso positivos para o GIV e falso negativos nos grupos GIII e GV. As análises comparativas entre as técnicas mostraram que a ordem de eficiência da sensibilidade para detecção de C. neoformans no soro foi SiB>SiA=Látex>SiC e no líquor foi SiB> SiA>tinta da China>Látex=SiC. No soro, a especificidade entre as técnicas foi SiB>SiA=Látex>SiC e no líquor foi SiB=tinta da China>Látex>SiA>SiC. De acordo com nossos dados, concluímos que, independente da doença associada (HIV) ou se o paciente for tratado, a SiB foi a melhor seqüência para a detecção de C. neoformans, tanto em amostras diretamente de soro, como de líquor para todos os grupos estudados. Tendo em vista os fatos, acreditamos que, a aplicação da técnica da Nested PCR com a \"SiB\", em amostras de líquor e soro, é um método viável e acurado para realizar o diagnóstico molecular do C. neoformans em pacientes HIV. O uso de amostras de soro, para o segmento dos pacientes com SIDA, durante o tratamento, pode ser a forma menos invasiva em relação ao líquor para a detecção do C. neoformans, com vantagens sobre os métodos utilizados / Cryptococcus neoformans (C. neoformans), a fungus that is widespread in many parts of the world, including Brazil, is responsible for cryptococcosis the most common opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). The systemic character of cryptococcosis may be fatal. In order to obtain a rapid and accurate laboratory diagnosis to follow - up of HIV-cryptococcosis patients led us to investigate the sensibility and especificity of three primers (A, B and C) of 18SrDNA, 5,8SrDNA and ITS regions of Cryptococcus spp. Using Nested PCR with those primers we suggest the best among them to be used as a method of molecular diagnosis in relation to the usual techniques. For this purpose, the serum and cerebrospinal fluid (CSF) of 39 patients, who had received medical treatment, were evaluated. All cases were separated in groups, as follows: 7 with cryptococcosis (group III), 14 HIV positive (group IV), 18 HIV positive associated with cryptococcosis (group V) were compared to, 10 healthy subjects (group I) controls, as well as to reference cultures (group II) samples. The results obtained by nested PCR with primers A and B and C were compared to those obtained by conventional diagnostic methods. The analyses of primers A, B and C detected C. neoformans both in serum (SiA 91,6%, SiB-100%, SiC 75%), and in CSF (SiA 83,3%, SiB 100% e SiC 75%). Besides, they were specific for the identification of C. neoformans and showed that there were no false positives when compared with heterologous cultures (group VI) samples. The primer B in CSF showed 100% sensitivity, 100% accuracy and 100% predictive values (positive and negative), and 100% specificity for the detection of C. neoformans, the same that occurs in serum, but in this case, with 88% in sensitivity, 89% predictive value negative and 94% accuracy. In serum and CSF samples the China Ink and the Latex tests showed false positive results for group IV and false negative for III and V groups. The comparative analysis among the techniques (Nested PCR, China Ink, Latex) indicated that the efficiency order of sensitivity for the detection of C. neoformans were PrB> PrA = Latex> PrC in serum and PrB > PrA > China Ink> Latex = PrC in CSF. For the serum and CSF specificities the same techniques were used with the following results: PrB>PrA=Latex>PrC and PrB=China Ink>Latex>PrA>PrC. According to our data we conclude that, whether the patients had been under treatment or not, the Nested PCR by PrB was the best way to detect C. neoformans both in serum and in CSF for all groups. The following up of AIDS patients, throughout the course of therapy was found to be feasible, accurate and less invasive to detect C. neoformans by using serum samples (directly)