ABSTRACT
In the context of a biorefinery, lignocellulosic materials represent an important source of raw material for the bioconversion of cellulose, hemicellulose, and lignin into value-added products, such as xylose for fermentation, oligosaccharides, and bioplastics for packaging. Among the most abundant lignocellulosic materials in Brazil, sugarcane bagasse biomass stands out, as it is rich in cellulose and hemicellulose. In this context, through an experimental design, this study developed a robust enzyme cocktail containing xylanases and accessory enzymes to complete the hydrolysis of xylan from sugarcane bagasse, obtaining a low xylose yield and concentration (9% and 1.8 g/L, respectively, observed in experiment number 16 from the complete hydrolysis of a xylan assay), a fermentable sugar that is important in the production of second-generation ethanol, and a high xylooligosaccharides (XOS) yield and concentration (93.1% and 19.6 g/L, respectively, obtained from a xylooligosaccharides production assay); in general, xylan has prebiotic activities that favor an improvement in intestinal functions, with immunological and antimicrobial actions and other benefits to human health. In addition to completely hydrolyzing the sugarcane bagasse xylan, this enzymatic cocktail has great potential to be applied in other sources of lignocellulosic biomass for the conversion of xylan into xylose and XOS due to its enzymes content, involving both main chain and pendant groups hydrolysis of hemicelluloses.
Subject(s)
Cellulose , Saccharum , Humans , Xylans , Xylose , Hydrolysis , Oligosaccharides , GlucuronatesABSTRACT
: Xanthomonas citri subsp. citri (X. citri) is the causal agent of Asiatic Citrus Canker (ACC), a disease that affects citrus. ACC has no cure, and growers must rely on special agricultural practices to prevent bacterial spreading. Understanding X. citri basic biology is essential to foresee potential genetic targets to control ACC. Traditionally, microbial genetics use gene deletion/disruption to investigate gene function. However, essential genes are difficult to study this way. Techniques based on small-RNAs and antisense-RNAs are powerful for gene characterization, but not yet fully explored in prokaryotes. One alternative is riboswitches, which derive from bacteria, and can control transcription/translation. Riboswitches are non-coding RNAs able to modulate gene expression in the presence of specific ligands. Here we demonstrate that the riboswitch theo/metE decreases parB expression in X. citri in a platform responsive to theophylline. By monitoring cell respiration, we showed that higher concentrations of the ligand interfered with bacterial viability. Therefore, we determined the safe dose of theophylline to be used with X. citri. Finally, in downstream investigations of parB transcription modulation, we show evidence for the fact that ParB is stable, remains functional throughout the cell cycle, and is inherited by the daughter cells upon cell division.
ABSTRACT
The 5S ribosomal DNA (rDNA) sequences are subject of dynamic evolution at chromosomal and molecular levels, evolving through concerted and/or birth-and-death fashion. Among grasshoppers, the chromosomal location for this sequence was established for some species, but little molecular information was obtained to infer evolutionary patterns. Here, we integrated data from chromosomal and nucleotide sequence analysis for 5S rDNA in two Abracris species aiming to identify evolutionary dynamics. For both species, two arrays were identified, a larger sequence (named type-I) that consisted of the entire 5S rDNA gene plus NTS (non-transcribed spacer) and a smaller (named type-II) with truncated 5S rDNA gene plus short NTS that was considered a pseudogene. For type-I sequences, the gene corresponding region contained the internal control region and poly-T motif and the NTS presented partial transposable elements. Between the species, nucleotide differences for type-I were noticed, while type-II was identical, suggesting pseudogenization in a common ancestor. At chromosomal point to view, the type-II was placed in one bivalent, while type-I occurred in multiple copies in distinct chromosomes. In Abracris, the evolution of 5S rDNA was apparently influenced by the chromosomal distribution of clusters (single or multiple location), resulting in a mixed mechanism integrating concerted and birth-and-death evolution depending on the unit.
Subject(s)
Chromosome Mapping/methods , DNA, Ribosomal/genetics , Grasshoppers/genetics , RNA, Ribosomal, 5S/genetics , Animals , Chromosomes/genetics , Evolution, Molecular , Female , Male , Pseudogenes , Sequence Analysis, DNA , Sequence Analysis, ProteinABSTRACT
Supernumerary chromosomes (B chromosomes) occur in approximately 15% of eukaryote species. Although these chromosomes have been extensively studied, knowledge concerning their specific molecular composition is lacking in most cases. The accumulation of repetitive DNAs is one remarkable characteristic of B chromosomes, and the occurrence of distinct types of multigene families, satellite DNAs and some transposable elements have been reported. Here, we describe the organization of repetitive DNAs in the A complement and B chromosome system in the grasshopper species Abracris flavolineata using classical cytogenetic techniques and FISH analysis using probes for five multigene families, telomeric repeats and repetitive C0t-1 DNA fractions. The 18S rRNA and H3 histone multigene families are highly variable and well distributed in A. flavolineata chromosomes, which contrasts with the conservation of U snRNA genes and less variable distribution of 5S rDNA sequences. The H3 histone gene was an extensively distributed with clusters occurring in all chromosomes. Repetitive DNAs were concentrated in C-positive regions, including the pericentromeric region and small chromosomal arms, with some occurrence in C-negative regions, but abundance was low in the B chromosome. Finally, the first demonstration of the U2 snRNA gene in B chromosomes in A. flavolineata may shed light on its possible origin. These results provide new information regarding chromosomal variability for repetitive DNAs in grasshoppers and the specific molecular composition of B chromosomes.
Subject(s)
Chromosomes, Insect , Grasshoppers/genetics , Histones/genetics , Animals , Chromosome Mapping , Cytogenetic Analysis , Female , Grasshoppers/cytology , In Situ Hybridization, Fluorescence , Male , Meiosis , Multigene Family , RNA, Ribosomal, 18S/genetics , RNA, Small Nuclear/genetics , Repetitive Sequences, Nucleic AcidABSTRACT
Dengue is an infectious disease of viral etiology transmitted by the mosquitoes Aedes aegypti, A. albopictus, and A. scutellaris. It can develop either as a benign form or as a severe hemorrhagic form. Previous work showed an association of the hemorrhagic form with human leukocyte antigens (HLA), suggesting a role of genetic factors in disease susceptibility. Nevertheless, data on HLA association with the classical form of the disease is scarce in literature. Sixty-four patients and 667 normal individuals, living in the state of Parana, Southern Brazil, were used as test and control group, respectively. The patients developed the disease during a virus 1 dengue outbreak either in Maringa city in 1995 (47) or in Paranavai city in 1999 (17). The diagnostic was confirmed through serology and/or viral culture. HLA class I and II typing was performed by the classical microlynfocitotoxicity test using monoclonal antisera and fluorobeads. Qui-square statistical analysis confirmed a positive association with HLA-DQ1 (76.6% vs 57.7%; p = 0.005243; pc = 0.026215). HLA-DR1 also presented an increased frequency in the test group, not statistically significant after p correction though (32.8% vs 15.9%; p = 0.005729; pc = 0.080206). In conclusion, genetic factors may play a role on the susceptibility to the classical dengue, virus 1, in the Brazilian population. Further independent studies should be performed in the Brazilian population to confirm these preliminary data.
Subject(s)
Dengue Virus/immunology , Dengue/genetics , Genetic Predisposition to Disease , HLA-DQ Antigens/genetics , Brazil , Case-Control Studies , Dengue/immunology , Female , HLA-DQ Antigens/immunology , Humans , Male , Risk FactorsABSTRACT
Dengue is an infectious disease of viral etiology transmitted by the mosquitoes Aedes aegypti, A. albopictus, and A. scutellaris. It can develop either as a benign form or as a severe hemorrhagic form. Previous work showed an association of the hemorrhagic form with human leukocyte antigens (HLA), suggesting a role of genetic factors in disease susceptibility. Nevertheless, data on HLA association with the classical form of the disease is scarce in literature. Sixty-four patients and 667 normal individuals, living in the state of Paraná, Southern Brazil, were used as test and control group, respectively. The patients developed the disease during a virus 1 dengue outbreak either in Maringá city in 1995 (47) or in Paranavaí city in 1999 (17). The diagnostic was confirmed through serology and/or viral culture. HLA class I and II typing was performed by the classical microlynfocitotoxicity test using monoclonal antisera and fluorobeads. Qui-square statistical analysis confirmed a positive association with HLA-DQ1 (76.6 percent vs 57.7 percent; p = 0.005243; pc = 0.026215). HLA-DR1 also presented an increased frequency in the test group, not statistically significant after p correction though (32.8 percent vs 15.9 percent; p = 0.005729; pc = 0.080206). In conclusion, genetic factors may play a role on the susceptibility to the classical dengue, virus 1, in the Brazilian population. Further independent studies should be performed in the Brazilian population to confirm these preliminary data.
Subject(s)
Humans , Male , Female , Dengue , Dengue Virus , Genetic Predisposition to Disease , HLA Antigens , Brazil , Case-Control Studies , Risk FactorsABSTRACT
A diminuição dos níveis séricos de lipídeos com a sinvastatina é reconhecidamente segura e eficaz, tendo comprovado impacto na redução do risco cardiovascular. O estudo avaliou o uso de um novo inibidor da HMG CoA redutase, a atorvastatina em relação a segurança e eficácia no tratamento da dislipidemia primária e mista. Foram estudados 28 pacientes de forma randomizada e aberta para atorvastatina e sinvastatina por 12 semanas, como parte de um estudo multicêntrico...
Subject(s)
Humans , Hypercholesterolemia/drug therapy , Simvastatin , Anticholesteremic Agents , Drug Evaluation , Randomized Controlled Trials as TopicABSTRACT
Objetivo: Avaliar a prevalência de anticorpos anticardiolipina (aCL) em populaçao selecionada de pacientes com abortamento recorrentes de causa indefinida. Material e métodos: Quarenta e três pacientes com histórico de no mínimo dois abortamentos espontâneos foram estudadas quanto à prevalência de aCL no soro. Presença de causas gineco-obstétricas de abortamentos e evidência de doenças difusas do tecido conjuntivo foram consideradas critérios de exclusao. A quantificaçao de IgG e IgM aCL foi realizada através de ELISA. Vinte soros de doadores de banco de sangue pareados por sexo e idade foram utilizados como controles. Resultados: Nenhuma paciente teve IgM aCL em níveis consideráveis no soro. Três pacientes (6,9 por cento) apresentaram níveis moderados ou altos de IgG aCL. Nenhum dos soros-controles apresentou aCL em níveis relevantes. A diferença de positividade para aCL entre pacientes e controles nao foi estatisticamente significante (p>0,54, teste de Fisher). Conclusoes: A prevalência de níveis significantes de aCL em nossa populaçao-alvo foi baixa. No entanto, o eventual diagnóstico de síndrome antifosfolipídica (SAFp), como confirmado em três de nossas pacientes, pode fazer perspectivas terapêuticas em futuras gestaçoes. Este dado corrobora a utilidade do teste aCL em casos de abortamentos repetidos de origem indefinida
Subject(s)
Humans , Female , Abortion, Spontaneous , Antibodies, Anticardiolipin , Antiphospholipid Syndrome , AutoantibodiesABSTRACT
No presente trabalho, os autores revisam os aspectos atuais relacionados ao tratamento do infarto agudo do miocárdio (IAM), através de uma análise das modalidades farmacológicas empregadas nesta entidade clínica, a partir dos resultados recentes de estudos multicêntricos
Subject(s)
Humans , Myocardial Infarction/therapy , Myocardial Reperfusion/methods , Thrombolytic Therapy , Thrombolytic Therapy/methodsABSTRACT
A terapia antiplaquetária na prevençäo da cardiopatia isquêmica tem sido alvo de numerosos estudos. Neste artigo, os autores fazem uma revisäo do papel da aspirina na prevençäo primária e secundária da cardiopatia isquêmica, documentando o impacto deste agente na reduçäo da morbi-mortalidade cardiovascular
