Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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174 resultados
Resultados da Pesquisa
Item Liquid-liquid equilibria in aqueous two-phase ethanol/salt systems at different temperatures and their application to anthocyanins extraction(Food Science and Technology, 2019-05-16) Sampaio, Fábio Coelho; Caldeira, Ana Clara Rocha; Converti, Attilio; Lima, William James Nogueira; Faria, Janaína Teles deAqueous two-phase systems (ATPS) are formed by mixtures of chemical species that, under certain conditions, separate into two immiscible phases, with water as the major component in global terms and, at lower concentrations, polymers, salts, ionic liquids and alcohols, depending on the system type. Different parameters influence ATPS equilibrium such as temperature, alcohol carbon chain size, salt type, pH, etc. The present work aimed to obtain the binodal curves for ATPS made up of ethanol, sodium citrate/ammonium sulfate and water at different temperatures (15, 25 and 35 °C) as well as to evaluate the potential of the ethanol/ammonium sulfate system in anthocyanins partition. The results showed that the increase in temperature did not alter the biphasic region in the temperature range investigated, not influencing the formation of phases. Nonlinear equations were satisfactorily fitted to binodal curves data, except for sodium citrate-containing ATPS at 15 °C. Higher concentration of the overall mixture resulted in longer tie-line of ammonium sulphate-containing ATPS. Higher values of partition coefficient and recovery yield of Syzygium cumini fruit anthocyanins were obtained at longer tie-lines.Item Cyrtopodium paludicolum germination with two Tulasnella isolates(Acta Botanica Brasilica, 2018-01) Carvalho, Otieres Cirino de; Paiva Neto, Vespasiano Borges de; Padilha, Daly Roxana Castro; Veloso, Tomás Gomes Reis; Bocayuva, Melissa Faust; Soares, Deanna Carla Oliveira; Kasuya, Maria Catarina MegumiSymbiosis between orchid seeds and mycorrhizal fungi has been reported to be a determining factor in the success of germination and protocorm development in vitro. Th e aim of this study was to isolate and identify by molecular analysis the mycorrhizal fungus associated with Cyrtopodium paludicolum, and to evaluate its effi ciency in facilitating seed germination and development. Germination experiments were carried out using a fungus isolated from C. paludicolum (CH01) and Epidendrum secundum (M65), which has been successfully used a number of times in symbiotic germination. Th e experiments were conducted in a completely randomized design with treatments of CH01, M65 as well as under asymbiotic conditions. Th e mycobiont CH01 was successfully isolated from Cyrtopodium paludicolum and identifi ed as Tulasnella sp. Treatments with both fungi reached a higher germination percentage than under asymbiotic conditions, indicating no specifi city in the relationship between Cyrtopodium paludicolum and the fungi. Th e results presented have the potential to advance research into the propagation and conservation of C. paludicolum, a native of the Cerrado biome.Item In vitro culture of Gigaspora decipiens and Glomus clarum in transformed roots of carrot: the influence of temperature and pH(Acta Scientiarum. Agronomy, 2013-07) Kasuya, Catarina Megumi; Costa, Francilina Araújo; Haddad, Lydice Sant'Anna Meira; Oton, Wagner Campos; Costa, Maurício Dutra; Borges, Arnaldo ChaerMonoxenic cultures of arbuscular mycorrhizal fungi (AMF) in transformed roots have been used to better understand the symbiosis with these fungi, but few species have been successfully established in vitro. The object was to establish monoxenic cultures of Gigaspora decipiens and Glomus clarum and to verify the effects of temperature and pH on spore formation. Cultures were established from superficially disinfested spores that were germinated on an agar and water. After germination, the spores were transferred to Petri dishes containing transformed carrot roots. After 4-6 days formed newly formed spores and structures typical. The effects of temperature (22, 25, 28 or 32ºC) and pH (4.0, 4.5, 5.5 or 6.5) on the production of spores were assessed over three months, resulting in sigmoidal growth curves. The spore increased from 22ºC, reaching higher values 28oC and 32oC there was a reduction in the production. The highest spore production of G. decipiens occurred in a pH of 6.5, whereas for G. clarum was pH of 4.0. The cultivation of other species is still necessary to elucidate particular aspects of the symbiosis that so far are unclear, including the effects of environmental factors on the production of spores of different AMF species.Item Screening and characterization of prophages in Desulfovibrio genomes(Scientific Reports, 2018) Crispim, Josicelli Souza; Dias, Roberto Sousa; Vidigal, Pedro Marcus Pereira; Sousa, Maíra Paula de; Silva, Cynthia Canêdo da; Santana, Mateus Ferreira; Paula, Sérgio Oliveira deBacteria of the genus Desulfovibrio belong to the group of Sulphate Reducing Bacteria (SRB). SRB generate significant liabilities in the petroleum industry, mainly due to their ability to microbiologically induce corrosion, biofilm formation and H2S production. Bacteriophages are an alternative control method for SRB, whose information for this group of bacteria however, is scarce. The present study developed a workflow for the identification of complete prophages in Desulfovibrio. Poly-lysogenesis was shown to be common in Desulfovibrio. In the 47 genomes analyzed 53 complete prophages were identified. These were classified within the order Caudovirales, with 69.82% belonging to the Myoviridade family. More than half the prophages identified have genes coding for lysozyme or holin. Four of the analyzed bacterial genomes present prophages with identity above 50% in the same strain, whose comparative analysis demonstrated the existence of colinearity between the sequences. Of the 17 closed bacterial genomes analyzed, 6 have the CRISPR-Cas system classified as inactive. The identification of bacterial poly-lysogeny, the proximity between the complete prophages and the possible inactivity of the CRISPR-Cas in closed bacterial genomes analyzed allowed the choice of poly-lysogenic strains with prophages belonging to the Myoviridae family for the isolation of prophages and testing of related strains for subsequent studies.Item In vitro probiotic potential and anti-cancer activity of newly isolated folate-producing Streptococcus thermophilus strains(Frontiers in Microbiology, 2018-09) Duarte, Vinicius da Silva; Tarrah, Armin; Castilhos, Juliana de; Rossi, Rochele Cassanta; Ziegler, Denize Righetto; Corich, Viviana; Giacomini, AlessioMost probiotic strains commercially available today are lactic acid bacteria. Withinthis functional group, Streptococcus thermophilus is a thermophilic species widely used as starter culture for a huge number of dairy products. Besides being rapid acidifiers, many S. thermophilus strains are able to produce and release folate during growth but, unfortunately, they are seriously impaired during passage through the human gastrointestinal tract. In this work, we studied eight S. thermophilus strains isolated from dairy environments in Italy, which already had shown good technological properties, to evaluate their possible probiotic potential and cytotoxicity against cancer cells in vitro. All strains were also evaluated for some health-related properties such as susceptibility to most common antibiotics, hemolytic activity, resistance to simulated gastrointestinal conditions, bile salts hydrolytic activity, production of folate, adhesion to HT-29 human colorectal adenocarcinoma cells and cytotoxic activity against cancer cells and production of biogenic amines. Results revealed that two fast acidifying S. thermophilus strains were found to possess in vitro probiotic properties along with anticancer activity and production of folate. These properties resulted similar and, in some cases, superior to those of Lactobacillus rhamnosus GG, a well-known commercial probiotic strain. These findings encourage further in vivo studies to evaluate the actual health benefits of these strains on the human host.Item Comparative transcriptomic analysis of Streptococcus thermophilus TH1436 and TH1477 showing different capability in the use of galactose(Frontiers in Microbiology, 2018-08) Duarte, Vinícius da Silva; Giaretta, Sabrina; Treu, Laura; Vendramin, Veronica; Tarrah, Armin; Campanaro, Stefano; Corich, Viviana; Giacomini, AlessioStreptococcus thermophilus is a species widely used in the dairy industry for its capability to rapidly ferment lactose and lower the pH. The capability to use galactose produced from lactose hydrolysis is strain dependent and most of commercial S. thermophilus strains are galactose-negative (Gal − ), although galactose-positive (Gal + ) would be more technologically advantageous because this feature could provide additional metabolic products and prevent galactose accumulation in foods. In this study, a next generation sequencing transcriptome approach was used to compare for the first time a Gal + and a Gal − strain to characterize their whole metabolism and shed light on their different properties, metabolic performance and gene regulation. Transcriptome analysis revealed that all genes of the gal operon were expressed very differently in Gal + and in the Gal − strains. The expression of several genes involved in mixed acid fermentation, PTS sugars transporter and stress response were found enhanced in Gal + . Conversely, genes related to amino acids, proteins metabolism and CRISPR associated proteins were under-expressed. In addition, the strains showed a diverse series of predicted genes controlled by the transcriptional factor catabolite control protein A (CcpA). Overall, transcriptomic analysis suggests that the Gal + strain underwent a metabolic remodeling to cope with the changed environmental conditions.Item A cryptic non-inducible prophage confers phage-immunity on the Streptococcus thermophilus M17PTZA496(Viruses, 2019-01) Duarte, Vinícius da Silva; Giaretta, Sabrina; Campanaro, Stefano; Treu, Laura; Armani, Andrea; Tarrah, Armin; Paula, Sérgio Oliveira de; Giacomini, Alessio; Corich, VivianaStreptococcus thermophilus is considered one of the most important species for the dairy industry. Due to their diffusion in dairy environments, bacteriophages can represent a threat to this widely used bacterial species. Despite the presence of a CRISPR-Cas system in the S. thermophilus genome, some lysogenic strains harbor cryptic prophages that can increase the phage-host resistance defense. This characteristic was identified in the dairy strain S. thermophilus M17PTZA496, which contains two integrated prophages 51.8 and 28.3 Kb long, respectively. In the present study, defense mechanisms, such as a lipoprotein-encoding gene and Siphovirus Gp157, the last associated to the presence of a noncoding viral DNA element, were identified in the prophage M17PTZA496 genome. The ability to overexpress genes involved in these defense mechanisms under specific stressful conditions, such as phage attack, has been demonstrated. Despite the addition of increasing amounts of Mitomycin C, M17PTZA496 was found to be non-inducible. However, the transcriptional activity of the phage terminase large subunit was detected in the presence of the antagonist phage vB_SthS-VA460 and of Mitomycin C. The discovery of an additional immune mechanism, associated with bacteriophage-insensitive strains, is of utmost importance, for technological applications and industrial processes. To our knowledge, this is the first study reporting the capability of a prophage integrated into the S. thermophilus genome expressing different phage defense mechanisms. Bacteriophages are widespread entities that constantly threaten starter cultures in the dairy industry. In cheese and yogurt manufacturing, the lysis of Streptococcus thermophilus cultures by viral attacks can lead to huge economic losses. Nowadays S. thermophilus is considered a well-stablished model organism for the study of natural adaptive immunity (CRISPR-Cas) against phage and plasmids, however, the identification of novel bacteriophage-resistance mechanisms, in this species, is strongly desirable. Here, we demonstrated that the presence of a non-inducible prophage confers phage-immunity to an S. thermophilus strain, by the presence of ltp and a viral noncoding region. S. thermophilus M17PTZA496 arises as an unconventional model to study phage resistance and potentially represents an alternative starter strain for dairy productions.Item Desulfovibrio alaskensis prophages and their possible involvement in the horizontal transfer of genes by outer membrane vesicles(Gene, 2019-06) Crispim, Josicelli Souza; Dias, Roberto Sousa; Laguardia, Clara Nogueira; Araújo, Larissa Cristina; Silva, Jéssica Duarte da; Vidigal, Pedro Marcus Pereira; Sousa, Maíra Paula de; Silva, Cynthia Canêdo da; Santana, Mateus Ferreira; Paula, Sérgio Oliveira de; Sousa, Maíra Paula deDesulfovibrio alaskensis is a Gram-negative bacterial species that belongs to the group of Sulphate Reducing Bacteria (SRB) and presents prophages in genomes, a common characteristic of the genus Desulfovibrio. Genetic material can be transported by outer membrane vesicles, however, no data regarding the production of these vesicles has been reported for D. alaskensis. To verify the expression of D. alaskensis prophages and their involvement with outer membrane vesicles, the DSM16109 strain was used. The DSM16109 strain had three prophages and presented reduced growth after mitomycin C addition when compared to the control culture. This reduction was accompanied by the presence of virus-like particles (VLPs), indicating mitomycin C dependent prophage induction. The increase in the number of cap gene copies and transcriptions of the three prophages was verified in the control sample, however, without the formation of VLPs. Prophage genes were identified in outer membrane vesicles from cultures treated and not treated with mitomycin C. DSM16109 prophages are expressed spontaneously but only in the presence of mitomycin C was it possible to observe VLP formation. Due to the genetic material detection from the prophages within outer membrane vesicles, this property may be related to the horizontal transfer of viral genes.Item Levantamento fitossociológico de plantas daninhas em pastagens no município de Nova Olímpia-MT(Revista Agraria, 2013-11) Mendes, Kassio Ferreira; Inoue, Miriam Hiroko; Iskierski, Daiane; Ben, Ronei; Conciani, Paulo Alberto; Pereira, Rafael Luiz; Dallacort, RivanildoO objetivo do trabalho foi identificar a comunidade infestante de plantas daninhas em áreas de pastagens no município de Nova Olímpia, MT. O levantamento foi realizado nos meses de fevereiro e março de 2012, em que foram analisadas 10 propriedades, tendo cada uma 10 parcelas de 25 m2. Nas parcelas foram realizadas a contagem e identificação das espécies daninhas. Os dados foram analisados por meio de cálculo de densidade, frequência, abundância, densidade relativa, frequência relativa, abundância relativa, índice de valor de importância (IVI) e índice de similaridade. Foram encontradas 31 espécies de plantas daninhas distribuídas em 16 famílias botânicas, sendo, Asteraceae (4), Papilionoideae (4) Poaceae (4) e Malvaceae (3) as mais representativas em números de espécies. As espécies mais ocorrentes foram Sida carpinifolia (IVI = 38,50), Sida spp. (IVI = 36,26), Chenopodium ambrosiodies (IVI = 21,06) e Sida cordifolia (IVI = 19,71). Foi encontrada similaridade expressiva entre as propriedades sendo que as propriedades 6 e 8 se destacaram com índice de similaridade de 78,26%.Item Addressing global ruminant agricultural challenges through understanding the rumen microbiome: past, present, and future(Frontiers in Microbiology, 2019) Mantovani, Hilario C.; Huws, Sharon A.; Creevey, Christopher J.; Oyama, Linda B.; Mizrahi, Itzhak; Denman, Stuart E.; Popova, Milka; Muñoz-Tamayo, Rafael; Forano, Evelyne; Waters, Sinead M.; Hess, Matthias; Tapio, Ilma; Smidt, Hauke; Krizsan, Sophie J.; Yáñez-Ruiz, David R.; Belanche, Alejandro; Guan, Leluo; et alThe rumen is a complex ecosystem composed of anaerobic bacteria, protozoa, fungi, methanogenic archaea and phages. These microbes interact closely to breakdown plant material that cannot be digested by humans, whilst providing metabolic energy to the host and, in the case of archaea, producing methane. Consequently, ruminants produce meat and milk, which are rich in high-quality protein, vitamins and minerals, and therefore contribute to food security. As the world population is predicted to reach approximately 9.7 billion by 2050, an increase in ruminant production to satisfy global protein demand is necessary, despite limited land availability, and whilst ensuring environmental impact is minimized. Although challenging, these goals can be met, but depend on our understanding of the rumen microbiome. Attempts to manipulate the rumen microbiome to benefit global agricultural challenges have been ongoing for decades with limited success, mostly due to the lack of a detailed understanding of this microbiome and our limited ability to culture most of these microbes outside the rumen. The potential to manipulate the rumen microbiome and meet global livestock challenges through animal breeding and introduction of dietary interventions during early life have recently emerged as promising new technologies. Our inability to phenotype ruminants in a high-throughput manner has also hampered progress, although the recent increase in “omic” data may allow further development of mathematical models and rumen microbial gene biomarkers as proxies. Advances in computational tools, high-throughput sequencing technologies and cultivation-independent “omics” approaches continue to revolutionize our understanding of the rumen microbiome. This will ultimately provide the knowledge framework needed to solve current and future ruminant livestock challenges.