• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 97
  • 81
  • 10
  • 6
  • 6
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 247
  • 247
  • 74
  • 55
  • 46
  • 37
  • 36
  • 31
  • 27
  • 26
  • 26
  • 24
  • 22
  • 22
  • 21
  • 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.
171

Age Matters: Community Assembly in the Pig Fecal Microbiome in the First Month of Life

Jurburg, Stephanie D., Bossers, Alex 27 March 2023 (has links)
Despite the wealth of research into strategies for microbiome modulation, studies of microbiome management in pig hosts have found mixed results. A refined understanding of the patterns of microbiome assembly during the host’s early life, when management strategies are most commonly applied, is necessary for the development of successful management practices. Here, we study the development of the pig gut microbial community in a monitoring experiment, sampling the microbiome of pigs in a commercial farm intensively during the first month of life. We found that the community’s taxonomic richness increased linearly with host age. Furthermore, rapid changes across communities occurred in stages, and non-linear patterns in relative abundance were commonly observed among dominant taxa across host age, consistent with primary succession. Our results highlight the importance of understanding the patterns of microbiome assembly during host development, and identify successional stages as windows of opportunity for future research.
172

COMPARATIVE STUDY OF CYANOBACTERIA OF DESERT AND SEMI-DESERT CRUSTS OF TWO DIFFERENT CONTINENTS: AFRICA (ETHIOPIA) AND NORTH AMERICA (USA)

Mesfin, Melaku 02 July 2009 (has links)
No description available.
173

Identification of Rhizobial Symbionts Associated with Lupinus SPP

Beligala, Dilshan Harshajith 24 July 2015 (has links)
No description available.
174

The Kinetics, Biochemical Patterns, and Microbial Ecology in Multiredox (Anoxic, Microaerobic, Aerobic) Activated Sludge Systems Treating BTX Containing Wastewater

Ma, Guihua 08 September 1999 (has links)
BTX biodegradation rates, biochemical expression patterns and microbial ecology were studied under anoxic (denitrifying), anoxic/microaerobic/aerobic, and anoxic/microaerobic conditions in activated sludge sequencing batch reactors. The studies showed that toluene and m-xylene were denitrified via benzoyl-CoA reductase. Although benzene, o-, and p-xylene were recalcitrant under denitrifying conditions, they were biodegraded under microaerobic (< 0.2 mg/L dissolved oxygen) and nitrate or nitrite (NOx)-supplemented microaerobic conditions. The patterns of the specific enzymes associated with BTX biodegradation under microaerobic conditions indicated that the three compounds were metabolized by oxygen-dependent pathways. The expression levels of catechol 1, 2-dioxygenase and catechol 2, 3-dioxygenase under microaerobic conditions were induced to levels as high as under aerobic conditions (> 4 mg/L dissolved oxygen). Benzene, o-, and p-xylene biodegradation rates were twice as fast under NO<sub>x</sub>-supplemented compared to NO<sub>x</sub>-free microaerobic conditions, and the specific biodegradation rates under aerobic and NO<sub>x</sub>-supplemented microaerobic conditions were comparable. 16S rRNA probes targeting representative toluene-degraders were used to investigate the microbial communities in the three sequencing batch reactors by using a dot blot hybridization technique. The hybridization results suggest that multiple redox environments fostered a more diverse microbial community and the activities of the target organisms in the reactors with multiple redox environments were higher than in the single redox reactor. Additionally, facultative toluene-degraders appeared to play a less significant role than the strict anoxic and aerobic toluene-degraders in all three SBRs. / Ph. D.
175

Mineralization of Nitrogen in Liquid Dairy Manure During Storage

Hu, Yihuai 15 July 2019 (has links)
Loss of nitrogen (N) from dairy manure during storage is an issue of economic, environmental, and social concern for farming communities. The lost N 1) decreases the value of manure as a fertilizer and is an economic loss because supplemental inorganic N fertilizer is purchased to meet N needs on farms; 2) produces the potential pollution for water and air systems, thereby damaging the associated ecosystems; 3) causes challenges to human health. Thus, it is vital to manage and use N in an efficient and eco-friendly manner. N mineralization is a pathway in the N cycle, which converts organic N to inorganic N that is more susceptible to loss. The objective of this study was to conduct lab-scale experiments to assess the effects of temperature, manure solids content, using manure seed and autoclave sterilization operation at the start of storage, and storage time on the N mineralization and the associated microbial community during the storage of liquid dairy manure. Manure scrapped from the barn floor of a commercial dairy farm and diluted to make experimental stocks with high (46 to 78 g/L) and low (19 to 36 g/L) total solids (TS), to simulate what is typically transported to the manure storage pit was used. The manure was incubated in the laboratory at three temperatures (10, 20, and 30°C) for two storage periods (60 and 180 days). Manure samples were taken at different storage time for analyses. The results showed that temperature and using sterilization operation at the start of storage had significant effects on N mineralization for both storage periods (p < 0.05). The highest N mineralization rate occurred at 30℃, which rate constant (k) was 0.096 week-1. While, the lowest N mineralization occurred at 10℃, and its corresponding k was 0.013 week-1. The concentrations of mineralized N (Nm) with non-sterilized (R) manure were significantly higher than that with sterilized (R0) manure (p < 0.05). Compared to that with high TS (H) manure, the concentrations of Nm were significantly higher with low TS (L) manure after 180-d storage (p < 0.05). Raw manure augmented with manure seed (MS) had significantly higher Nm than the manure seed only (SO) (p < 0.05). In order to investigate the changes of microbial community in manure, samples were collected on days 0, 30, 90, and 180 for the 180-d storage experiment, and days 0, 30, and 60 for the 60-d storage experiment, and then manure DNA under different condition was successfully extracted from collected samples and used for 16S rRNA sequencing. This study provided a more comprehensive understanding of the impact factors for manure storage, and was expected to clarify the relationship between N mineralization and the associated microbial community. / Master of Science / Loss of nitrogen (N) from dairy manure during storage is rooted in the process of degradation via microbial activities. During storage of dairy manure, up to 60% of N can be lost to the environment (the air, rivers, groundwater, etc.), causing damages such as global warming and water pollution. However, it is challenging to manage and reduce the N lost during manure storage because of lack of comprehensive knowledge of the complex microbial activities in manure storage structures. Thus, the long-term goal of this study is to discern the interactions of the physical, chemical, and microbial processes that affect the N transformation. The generated information will help to mitigate/minimize the loss of nitrogenous gases during storage of dairy manure. The specific objectives included: 1) to evaluate the effects of selected factors (including storage time, temperature, manure solids content, using manure seed and sterilization operation at the beginning of storage) on N mineralization during storage of liquid dairy manure and determine the associated N mineralization rate; 2) to reveal the microbial communities in stored liquid dairy manure under different conditions (listed above). The outcome of this study could be used to refine N mineralization input parameter of manure storage submodules of the process-based models such as Manure DeNitrification-DeComposition model (Manure-DNDC) and Integrated Farm System Model (IFSM) with the goal to improve their accuracy of estimating or accounting for the fate or cycling of N in dairy manure during storage.
176

Mikrobiální společenstva a metagenom průmyslově znečištěných půd: výskyt genů kódujících AEH / Microbial consortia and metagenome of industrially polluted soil: occurrence of genes encoding AEH

Pitkina, Anastasiya January 2015 (has links)
Soils contain highly diverse consortia of bacteria making them very attractive starting points for both culture-dependent and metagenomic discovery efforts. The present diploma thesis analyses the composition of the microbial community from pharmaceutically polluted soil, with the employment of next-generation Illumina sequencing of 16S rDNA region. This analysis revealed high complexity of the soil microbial environment and confirmed that anthropogenic activity (represented by production of beta- lactam antibiotics) influences the variability and abundance of the species, yet without reducing the microbial diversity. In the second part of the thesis, isolation and heterologous expression of a novel gene encoding alpha-amino acid ester hydrolase (AEH) from a cultivable soil microorganism B. cereus is described. AEHs possess industrial potential for biocatalytic synthesis of semi-synthetic beta-lactam antibiotics, which are presently of great clinical importance. Powered by TCPDF (www.tcpdf.org)
177

Caracterização molecular da estrutura genética de populações e espécies camarões palemonídeos Macrobrachium do gênero Macrobrachium /

Guerra, Ana Letícia. January 2011 (has links)
Orientador: Lílian Castiglioni-Ruiz / Banca: Fabiano Gazzi Taddei / Banca: Hermione Elly Melara de Campos Bicudo / Resumo: Os camarões do gênero Macrobrachium pertencem à família Palaemonidae. Habitam as proximidades do litoral e, também, ambientes de água doce. Com mais de cem espécies amplamente distribuídas pelas regiões tropicais e subtropicais do mundo, os palemonídeos possuem hábitos crípticos e noturnos. Particularmente na região noroeste do Estado de São Paulo, podemos encontrar várias espécies com importância econômica e ecológica consideráveis. Entretanto, existem poucos estudos na literatura relacionados ao conhecimento da biologia desses crustáceos. Assim, o presente trabalho objetivou analisar a variabilidade genética intra e interpopulacional, de amostras de duas espécies de camarões palemonídeos do gênero Macrobrachium (M. amazonicum e M. jelskii), coletadas em diferentes localidades, utilizando-se a análise das seqüências dos genes mitocondriais COI e rRNA 16S e, ainda, devido à problemática taxonômica existente entre essas duas espécies, também foi analisada a variabilidade genética interespecífica, utilizando-se os mesmos genes.. O cálculo dos índices de divergência genética intrapopulacionais apresentou valores baixos, refletindo uma provável estruturação genética destas populações. Apenas as populações de MjME e do CAUNESP apresentaram valores de divergência genética mais elevados, sugerindo um desequilíbrio na estruturação genética das mesmas, provavelmente causado por interferência antrópica e situação de cativeiro, respectivamente. Nas comparações interpopulacionais, envolvendo M. amazonicum, as taxas de divergência genética apresentaram uma ampla variação, também com média elevada. Os valores elevados nas comparações envolvendo a população do CAUNESP, permitiram descartar a hipótese da provável origem comum das populações de Macrobrachium, a partir de espécimes trazidos do Pará. Da mesma forma, as comparações... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The genus Macrobrachium (Bate, 1868) belongs to the Palaemonidae family. Their species are widely distributed in lakes, floodplains and rivers in tropical and subtropical regions of South America, having cryptic and nights habits. This genus presents nearly 210 known species with ecological and economic importance. Particulary in the northwestern state of São Paulo, we can find several species with considerable importance. However, there are few studies related to knowledge of the biology of these crustaceans. The aim this work was to analyze the genetic variability interpopulation, and interspecific of two Macrobrachium species (M. amazonicum and M. jelskii), using the mitochondrial gene sequence COI and 16S rRNA. Also, due to taxonomic problems between these two species we analyzed interspecific genetic variability, using the same genes. The intrapopulation rates of genetic divergence values were low, reflecting a probable genetic structure of these populations. Only populations MjME and CAUNESP showed higher divergence values, suggesting changes in their genetic structure of the same, probably caused by human interference and situation of captivity, respectively. In comparisons inferences involving M. amazonicum, rates of genetic divergence showed a wide range, also with high average. High values in comparisons involving the population of CAUNESP, allowed to reject the hypothesis of a probable common origin of populations the Macrobrachium specimens brought from State of Para. Interpopulation comparisons involving M. jelskii also showed high values of divergence, especially for the population collected from the Mendonça dam, whose genetic alteration in population structure was attributed to the frequent introduction of exotic specimens. The values of interspecific genetic divergence in the samples collected in the same geographic location were low for populations Adolfo (0.3%) ...(Complete abstract click electronic access below) / Mestre
178

Diversidade bacteriana do solo sob cultivo de cana-de-açúcar / Soil bacterial diversity under sugarcane field

Morais, Marcio 05 September 2008 (has links)
Os microrganismos representam a forma de vida mais abundante e diversificada do planeta. A atividade agrícola leva a uma redução da biodiversidade do solo e a menor diversidade microbiana pode resultar na diminuição da ciclagem de nutrientes e no crescimento das plantas. Como forma de avaliar alterações na atividade microbiana e na estrutura das comunidades de bactérias do solo, decorrentes do cultivo da cana-de-açúcar, foram conduzidos dois experimentos. O primeiro, no município de Novo Horizonte (SP), com o objetivo de determinar ação da queima da cana-de-açúcar sobre a comunidade de bactérias do solo e o segundo experimento, nos municípios de Pirassununga (SP) e Jaboticabal (SP), com o objetivo de verificar o efeito da adubação nitrogenada sobre a comunidade bacteriana do solo. Amostras de terra foram coletadas nas profundidades 0-10 e 10-20 cm, na linha e entrelinha de plantio. No primeiro experimento foram utilizadas três cultivares de cana-de-açúcar (SP81-3250, SP80-1842 e RB72-454) sob os sistemas de manejo de colheita sem queima (mecanizada) e com queima (manual) prévia a colheita. Nesse experimento foram avaliadas a diversidade metabólica (Biolog) e a estrutura das comunidades bacterianas por meio da PCR-DGGE do gene rRNA 16S. A mudança no manejo de colheita da cana-de-açúcar provocou modificações no metabolismo heterotrófico do solo, alterando a diversidade metabólica. No entanto, não houve mudanças na estrutura das comunidades bacterianas do solo com e sem queima sob a variedade SP801842. Dessa forma, a primeira queima da cana-de-açúcar previamente à colheita alterou a capacidade e a diversidade metabólica microbiana, mas não mudou a estrutura das comunidades de bactérias em relação à área sem queima. No segundo experimento foram avaliadas amostras de terra, de duas áreas experimentais, sob cultivo de cana-de-açúcar (SP813250), com diferentes doses de N (0, 40, 80 e 120 kg de N ha-1) na forma de uréia, aplicadas no sulco de plantio. Para verificar possíveis alterações na comunidade bacteriana desses solos, foram avaliadas a estrutura das comunidades bacterianas por PCR-DGGE e a diversidade de bactérias oxidadoras de amônio (AOB), pelo seqüenciamento de bibliotecas do gene rRNA 16S, utilizando oligonucleotídeos iniciadores específicos. As doses de N alteraram a estrutura das comunidades bacterianas do solo nas duas áreas experimentais, determinadas por PCR-DGGE, entretanto, a adubação nitrogenada não alterou a diversidade de AOB no solo, das duas áreas. A estrutura da comunidade de AOB no solo da USA, sem adubação nitrogenada e com 80 kg de N ha-1 diferiu estatisticamente. Nas duas áreas, as unidades taxonômicas operacionais mais abundantes se relacionam filogeneticamente a Nitrosospira multiformes. / The microorganisms are the most abundant and diverse living creatures on earth. The agricultural practices reduce the soil biodiversity and a lower microbial diversity can result in a nutrient cycling and plant growth reduction. Two sugarcane crops experiments were investigated to evaluate modifications in the microbial activity and soil bacterial communities structure. The first of them was done at municipality of Novo Horizonte, Sao Paulo State (SP), and it has the aim to determine the sugarcane burn effects on soil bacterial community. The second experiment was introduced at municipalities of Pirassununga (SP) and Jaboticabal (SP) with the objective to verify the nitrogen fertilizing effect on soil bacterial community. The soil samples were taken in 0-10 cm and 10-20 cm depth, between and in the planting furrows. We used three sugarcane varieties (SP81-3250, SP80-1842 e RB72-454) in the first experiment under unburned and burned sugarcane pre-harvest. We evaluated metabolic diversity (Biolog) and the bacterial community structure performing PCR-DGGE of 16S rRNA gene in the first experiment. The sugarcane harvest management had modified the soil heterotrophic metabolism by altering its diversity. In spite of that, there is no difference between the burned and unburned soil bacterial communities under the variety SP80-1842. For that reason, the first year pre harvest burn altered the microbial metabolic diversity and capacity but did not change the bacterial community structure when related with unburned area. In the second experiment, soil samples under the SP81-3250 variety were analyzed from two sites. Each site received different levels of urea as nitrogen fertilization (0, 40, 80 e 120 kg de N ha-1) applied at planting furrows. The PCR-DGGE was applied to verify changes in the bacterial communities structure in these soils. The ammonia-oxidizing bacteria (AOB) diversity was evaluated by sequencing of 16S rRNA gene libraries after the amplification with specific primers. The levels of nitrogen fertilization altered the soil bacterial communities structure in both study sites, by PCRDGGE evaluation. However, the nitrogen application did not alter the soil AOB diversity in those two sites. The soil AOB community structure under no nitrogen and 80 kg N ha-1 application was different from the community structure under the other levels of fertilization in one of the two sites. The operational taxonomic unit are phylogenetically related to Nitrosospira multiformes in the two sites.
179

Seleção de estirpes eficientes para fixação biológica de nitgrogênio e promoção de crescimento em plantas da espécie Brachiaria brizantha / Selection of efficient strains for biological nitrogen fixation and growth promotion of Brachiaria brizantha

Silva, Mylenne Calciolari Pinheiro da 24 September 2010 (has links)
A Brachiaria brizantha é considerada uma das forrageiras preferidas entre os agropecuaristas por possuir elevada produção de forragem, tolerância ao calor e ao déficit hídrico, alta resposta à aplicação de fertilizantes, produção em grande massa de raízes e sementes, resistência à cigarrinha das pastagens (exceto as pertencentes ao gênero Mahanarva) e boa competição com plantas invasoras. É considerada a principal fonte de alimento para bovinos, sendo utilizada tanto na cria, recria, como na engorda dos animais. As bactérias fixadoras de nitrogênio ou diazotróficas são procariotos capazes de reduzir o N2 a NH3, forma assimilável pelos organismos, e também podem produzir hormônios vegetais, como ácido-indol-acético, que estimulam o crescimento radicular da planta. Estes micro-organismos apresentam grande importância para a manutenção dos ecossistemas. Sua associação com as raízes de plantas e seu efeito promotor quando associados à Brachiaria brizantha possibilitaria a recuperação de áreas de pastagens que apresentam deficiência de nitrogênio, o que é um mecanismo ainda pouco explorado. Com o objetivo de estudar esta possibilidade, foram escolhidas três áreas (Nova Odessa-SP, São Carlos- SP e Campo Verde-MT), preferencialmente onde o nitrogênio era limitante, constituídas por pastagem de Brachiaria brizantha para a amostragem de solo e raiz. Os três locais demonstraram a ocorrência de diazotróficos, após o isolamento e cultivo das bactérias em meio de cultivo semisólido sem adição de nitrogênio na forma combinada (JNFb). Foram obtidas 110 estirpes bacterianas e, após sorteio aleatório, 72 isolados foram mantidos para realização de testes a fim de se avaliar o potencial biotecnológico das bactérias. Destes, 10 demonstraram atividade da nitrogenase quando submetidos ao método de aumento na concentração de nitrogênio total (Ntotal) em meio de cultura. 57 isolados foram capazes de reduzir o gás acetileno a etileno quando submetidos à técnica de redução de acetileno. As estirpes bacterianas C4 (Pseudomonas sp.) e C7 (Azospirillum sp.), isoladas da rizosfera de Brachiaria brizantha da área de Campo Verde-MT, se destacaram das demais por apresentar atividade da nitrogenase muito superior até a de bactérias diazotróficas que foram incluídas na avaliação como testemunhas positivas. Outros 68 isolados produziram o hormônio vegetal ácido-indol-acético quando cultivados em meio de cultivo LB, na presença de triptofano. A produção variou de 0,39µg/mL a 195 µg/mL de AIA. Todos os 72 isolados foram utilizados em experimento em casa de vegetação para avaliar o efeito de inoculação em B. brizantha quando com eles inoculada. Avaliaram-se a matéria seca da parte aérea e raiz e o teor de nitrogênio total da parte aérea através do método micro-Kjeldhal. Nenhum isolado diferiu significativamente do controle sem inoculação bacteriana que continha a mesma dose de nitrogênio fornecido às plantas. O seqüenciamento parcial do gene 16S rRNA dos 72 isolados permitiu a caracterização de sete grupos genotípicos: Stenotrophomonas sp, Pseudomonas sp., Xanthomonas sp., Bacillus sp., Rhizobium sp, Sphingomonas sp. e Azospirillum sp. O gênero Stenotrophomonas sp. predominou (69%) nas três áreas de estudo. / Brachiaria brizantha is considered one of preferred fodders among farmers for having high forage yield, tolerance to heat and drought, high response to fertilizer application, large production of root mass and seeds, resistance to grassland leafhopper (except those belonging to the genus Mahanarva) and good competition with weeds. It is considered the main source of food for cattle, being used in the raising, breeding, and fattening of animals. The nitrogen fixing bacteria or diazotrophs are prokaryotes able to reduce N2 to NH3, which is assimilated by organisms, and may also produce plant hormones such as indole-acetic acid, which stimulates root growth. These micro-organisms have great importance for the maintenance of ecosystems. Their association with plant roots and their promoting effect when combined with Brachiaria brizantha enable recovery of nitrogen-deficient grazing areas, which is a mechanism still little explored. Therefore, three areas were chosen (Nova Odessa-SP, Sao Carlos-SP and Campo Verde-MT), preferably where nitrogen was limiting, consisting of Brachiaria brizantha from which samples of soil and roots were collected. The three sites showed the occurrence of diazotrophs after the isolation and cultivation of bacteria in semi-solid culture medium with no nitrogen added in the combined form (JNFb). It was obtained 110 bacterial strains and, after the raffle random, 72 were kept isolated for testing in order to assess the biotechnological potential of bacteria. From which, 10 showed nitrogenase activity when subjected to the method of total nitrogen concentration increase (N-total) in the culture medium. 57 isolates were able to reduce acetylene to ethylene when subjected to the acetylene reduction technique. The strains C4 (Pseudomonas sp.) and C7 (Azospirillum sp.), isolated from the rhizosphere of Brachiaria brizantha in the area of Campo Verde-MT, stood out from the others by presenting nitrogenase activity far superior to that of diazotrophs recommended as positive controls. Other 68 isolates produced the plant hormone indole-acetic acid when grown in LB culture medium in the presence of tryptophan. Production ranged from 0.39 g/mL to 195 g/mL of IAA. All 72 isolates were used in an experiment in a greenhouse to evaluate the effect of inoculation on B. brizantha. Evaluations were carried out on dry matter of shoot and root and total nitrogen content of the shoot through the micro-Kjeldahl method. None of the isolates differed significantly from the control without bacterial inoculation which contained the same amount of nitrogen supplied to plants. Partial sequencing of the 16S rRNA of the 72 isolates allowed the characterization of seven genotype groups: Stenotrophomonas sp., Pseudomonas sp., Xanthomonas sp., Bacillus sp., Rhizobium, Sphingomonas sp. and Azospirillum sp. The genus Stenotrophomonas sp. predominated (69%) in the three study areas.
180

Diversidade bacteriana do gene 16S rRNA em carvão pirogênico de Terra Preta Antropogênica da Amazônia Central e Oriental / Bacterial diversity of the 16S rRNA gene in pyrogenic black carbon of Anthropogenic Dark Earth from the Central and Oriental Amazon

Terceti, Mateus de Souza 28 August 2009 (has links)
A Terra Preta Antropogênica (TPA) tem essa denominação porque é encontrada em sítios arqueológicos, onde viveram grupos pré-históricos e é considerada um dos solos mais férteis do mundo. Nela é encontrada grande quantidade de material deixado por grupos indígenas como fragmentos cerâmicos, artefatos líticos, e especialmente carvão pirogênico. Estudos realizados com o carvão pirogênico verificaram que ele aumenta a capacidade de trocas catiônicas nesses solos. Por meio de microscopia de fluorencência, foi observada a presença de microrganismos habitando esse carvão, no entanto, não se sabe quais seriam. Devido à falta de informações sobre a diversidade bacteriana nessas estruturas, este trabalho estudou a diversidade bacteriana em amostras de carvão pirogênico de solos TPA coletadas nos sítios Lagoa Balbina (Amazônia Central- Amazonas) e Mina I (Amazônia Oriental - Pará), através de técnicas moleculares independentes de cultivo. O estudo visou também comparar essa diversidade com a encontrada no solo de onde carvão foi isolado. As estruturas de carvão foram separadas fisicamente dos solos e seu DNA genômico total extraído e usado como molde em reação de PCR utilizando oligonucleotídeos do gene 16S rRNA para o Domínio Bacteria. O produto da PCR foi clonado em vetor e os clones foram sequenciados e comparados com o banco de dados de 16S rRNA do RDPX. Com a construção das bibliotecas de clones do gene 16S rRNA a partir das amostras de carvão pirogênico observou-se que existe maior número de bactérias desconhecidas no carvão pirogênico do que no solo onde ele foi isolado. Acidobacteria foi o filo predominante nas bibliotecas de carvão pirogênico das duas localidades de estudo, assim como na biblioteca do solo do sítio Mina I. Já na biblioteca do solo do sítio Lagoa Balbina houve predominância do filo Firmicutes. Por meio do método de rarefação foi possível constatar uma menor riqueza de UTOs nas comunidades bacterianas presentes nas estruturas de carvão pirogênico quando comparado à riqueza de UTOs das comunidades bacterianas cujo habitat é o solo. Mas quando se compara a riqueza de UTOs entre as estruturas de carvão isoladas das duas localidades, observa-se que a riqueza é maior no sítio Mina I. Os valores obtidos com os índices de diversidade revelaram menor diversidade de UTOs nas bibliotecas obtidas para o carvão pirogênico das duas regiões estudadas se comparado dos valores para as bibliotecas obtidas do solo da mesma região. Os valores obtidos com os métodos não paramétricos revelaram maior riqueza de UTOs para as bibliotecas do carvão do sítio Mina I e solo TPA do sítio Balbina. A análise da PCA revelou que as bibliotecas do sítio Balbina mostraram-se altamente similares. Em adição, a análise com S-Libshuff, verificou que todas as bibliotecas comparadas são significativamente diferentes quanto à composição das comunidades bacterianas. O carvão pirogênico não é uma estrutura inerte, pois é capaz de ser habitado por diferentes bactérias e a sua estrutura da comunidade bacteriana é diferente daquela de onde ele foi segregado / Anthropogenic Dark Earth (ADE) has this denomination because it is found at archeological sites, where prehistoric groups lived, and it is considered one of the most fertile soils of the world. In this soil a great amount of material left by indigenous groups was found as ceramic fragments, lithic workmanships, and especially pyrogenic black carbon. Studies accomplished with the pyrogenic black carbon verified that it increases the capacity of cationic changes in soils. Through fluorescence microscopy, the presence of microorganisms was observed inhabiting that black carbon, however, this community is still unknown,due to the lack of information about the bacterial diversity in those structures.This work studied the bacterial diversity in samples of pyrogenic black carbon of ADE soils, collected at the sites Lagoa Balbina (Central Amazon) and Mina I (Oriental Amazon), through molecular techniques independent of cultivation. The study also sought to compare that diversity with the one of the soil where black carbon was isolated. The structures of black carbon were separate physically from the soils and total genomic DNA was extracted and used as template in a PCR reaction, using primers of the 16S rRNA gene for the Bacteria Domain. The PCR product was used for construction of clone libraries and the clones were sequenced and compared with the 16S rRNA of RDPX database. The 16S rRNA gene clone libraries from the samples of pyrogenic black carbon, it shown that is a larger number of unknown bacteria in the black carbon than in the soil where it was isolated. Acidobacteria was the predominant phylum in the pyrogenic black carbon libraries from the both studied places, as well as in the soil library from Mina I site. However in the library Lagoa Balbina site there was predominance of the phylum Firmicutes. Through the rarefaction method it was possible to verify a smaller richness of OTUs in the bacterial communities presents in the pyrogenic black carbon structures when compared to the OTUs richness of the bacterial soil communities.But, when the OTUs richness is compared among the isolated structures of pyrogenic black carbon of the two places, it is observed that the richness is higher in the Mina I site. The values from diversity indexes revealed smaller diversity of OTUs in the pyrogenic black carbon libraries when compared with the soil libraries for the two studied areas. The obtained values with the nonparametric methods revealed larger OTUs richness in the black carbon library of Mina I site and in the ADE soil library of the Balbina site. The PCA analysis showed that the libraries of the site Balbina site were highly similar. In addition, the analysis with S-Libshuff verified that all of the compared libraries were significantly different in bacterial communities composition. The pyrogenic black carbon is not an inert structure, once it is capable of being inhabited by different bacteria, and its bacterial community structure is different from that one where is was segregated

Page generated in 0.0464 seconds