47 research outputs found
Decolorization and Biodegradation of basic violet dye by fungal- bacterial consortia
The present study was aimed to test the ability of Penicillium citrinum MTCC 8009, Aspergillusterreus MTCC 3006, Bacillus cohnii and their consortia to decolorize basic violet dye. Different parameters such as initial dye concentration, dye to inoculum ratio and period of incubation were studied for the decolourization of the dye. The developed fungal-bacterial consortia exhibited maximum percent decolorization (92%) ability when compared to the treatment of dyes by individual microbes. Percent decolorization of basic violet dye (92%) was more efficient using fungal-bacterial (Penicillium citrinum and Bacillus cohnii) consortia than with individual cultures. Phyto-toxicity results indicated that bacterial-fungal consortia (Penicillium citrinum and Bacillus cohnii) treatment was believed to degrade the dyes to non-toxic intermediates. The FTIR analysis also revealed that decolorization of basic violet dyes was due to its degradation
Regulation of DNA Methylation Patterns by CK2-Mediated Phosphorylation of Dnmt3a
DNA methylation is a central epigenetic modification that is established by de novo DNA methyltransferases. The mechanisms underlying the generation of genomic methylation patterns are still poorly understood. Using mass spectrometry and a phosphospecific Dnmt3a antibody, we demonstrate that CK2 phosphorylates endogenous Dnmt3a at two key residues located near its PWWP domain, thereby downregulating the ability of Dnmt3a to methylate DNA. Genome-wide DNA methylation analysis shows that CK2 primarily modulates CpG methylation of several repeats, most notably of Alu SINEs. This modulation can be directly attributed to CK2-mediated phosphorylation of Dnmt3a. We also find that CK2-mediated phosphorylation is required for localization of Dnmt3a to heterochromatin. By revealing phosphorylation as a mode of regulation of de novo DNA methyltransferase function and by uncovering a mechanism for the regulation of methylation at repetitive elements, our results shed light on the origin of DNA methylation patterns
Statistical Inference of In Vivo Properties of Human DNA Methyltransferases from Double-Stranded Methylation Patterns
DNA methyltransferases establish methylation patterns in cells and transmit these patterns over cell generations, thereby influencing each cell's epigenetic states. Three primary DNA methyltransferases have been identified in mammals: DNMT1, DNMT3A and DNMT3B. Extensive in vitro studies have investigated key properties of these enzymes, namely their substrate specificity and processivity. Here we study these properties in vivo, by applying novel statistical analysis methods to double-stranded DNA methylation patterns collected using hairpin-bisulfite PCR. Our analysis fits a novel Hidden Markov Model (HMM) to the observed data, allowing for potential bisulfite conversion errors, and yields statistical estimates of parameters that quantify enzyme processivity and substrate specificity. We apply this model to methylation patterns established in vivo at three loci in humans: two densely methylated inactive X (Xi)-linked loci ( and ), and an autosomal locus (), where methylation densities are tissue-specific but moderate. We find strong evidence for a high level of processivity of DNMT1 at and , with the mean association tract length being a few hundred base pairs. Regardless of tissue types, methylation patterns at are dominated by DNMT1 maintenance events, similar to the two Xi-linked loci, but are insufficiently informative regarding processivity to draw any conclusions about processivity at that locus. At all three loci we find that DNMT1 shows a strong preference for adding methyl groups to hemi-methylated CpG sites over unmethylated sites. The data at all three loci also suggest low (possibly 0) association of the de novo methyltransferases, the DNMT3s, and are consequently uninformative about processivity or preference of these enzymes. We also extend our HMM to reanalyze published data on mouse DNMT1 activities in vitro. The results suggest shorter association tracts (and hence weaker processivity), and much longer non-association tracts than human DNMT1 in vivo
Persistent activation of interlinked type 2 airway epithelial gene networks in sputum-derived cells from aeroallergen-sensitized symptomatic asthmatics
© 2018 The Author(s). Atopic asthma is a persistent disease characterized by intermittent wheeze and progressive loss of lung function. The disease is thought to be driven primarily by chronic aeroallergen-induced type 2-associated inflammation. However, the vast majority of atopics do not develop asthma despite ongoing aeroallergen exposure, suggesting additional mechanisms operate in conjunction with type 2 immunity to drive asthma pathogenesis. We employed RNA-Seq profiling of sputum-derived cells to identify gene networks operative at baseline in house dust mite-sensitized (HDM S ) subjects with/without wheezing history that are characteristic of the ongoing asthmatic state. The expression of type 2 effectors (IL-5, IL-13) was equivalent in both cohorts of subjects. However, in HDM S -wheezers they were associated with upregulation of two coexpression modules comprising multiple type 2- and epithelial-associated genes. The first module was interlinked by the hubs EGFR, ERBB2, CDH1 and IL-13. The second module was associated with CDHR3 and mucociliary clearance genes. Our findings provide new insight into the molecular mechanisms operative at baseline in the airway mucosa in atopic asthmatics undergoing natural aeroallergen exposure, and suggest that susceptibility to asthma amongst these subjects involves complex interactions between type 2- and epithelial-associated gene networks, which are not operative in equivalently sensitized/exposed atopic non-asthmatics
Evaluation of genotoxic and cytotoxic effects of hydroalcoholic extract of Euphorbia tirucalli (Euphorbiaceae) in cell cultures of human leukocytes
Fagocitose intensificada de Corynebacterium pseudotuberculosis por cĂ©lulas da sĂ©rie monĂłcito-macrĂłfago de caprinos naturalmente infectados pelo vĂrus da artrite encefalite
Kinetics of chemokine secretion in human macrophages infected with various strains of Mycobacterium tuberculosis
tuberculosis is infl uenced by the virulence of the strain, and it is suggested that virulence-associated differences in
chemokine secretion contribute to the failure in containing the infection due to poor granuloma formation. Materials
and Methods: In this study, we used prevalent M tuberculosis clinical strains (S7 and S10) to study the chemokine
secretion profi le in infected THP-1 cells and monocyte-derived macrophages (MDM) and compared this with the
chemokine secretion induced by laboratory strains. Results: This study showed that comparatively lower levels
of IP-10 were induced by clinical strains than by laboratory strains in both differentiated THP-1 and MDMs. The
secretion of MIP-1α was also depressed but only in the THP-1 cells infected with clinical strains. This depressed
chemokine secretion may hinder the movement of Th-1 cells from the periphery into the infection foci to control the
infection. Correlation between IP-10 and IL-12p40 showed a negative relationship in control MDMs, while there was
a positive correlation in all the infected strains, indicating their cooperative role in attracting and activating Th1 cells
for a protective immune response at the site. This relationship was strain dependent, with avirulent H37Ra showing
higher correlation, followed by the clinical strains and the virulent H37Rv. A positive correlation of IP-10 with IFN-Îł
(S7 and H37Ra) and with IL-10 (H37Ra and H37Rv) suggested a defi nitive interplay of these molecules in infection.
Conclusions: The chemokines secretion by infected THP-1 cells and MDMs was strain dependant and the lower
induction by the clinical strain
Kinetics of chemokine secretion in human macrophages infected with various strains of Mycobacterium tuberculosis
Background and Purpose: It has been shown that chemokine secretion upon
infection with Mycobacterium tuberculosis is influenced by the
virulence of the strain, and it is suggested that virulence-associated
differences in chemokine secretion contribute to the failure in
containing the infection due to poor granuloma formation. Materials and
Methods: In this study, we used prevalent M tuberculosis clinical
strains (S7 and S10) to study the chemokine secretion profile in
infected THP-1 cells and monocyte-derived macrophages (MDM) and
compared this with the chemokine secretion induced by laboratory
strains. Results: This study showed that comparatively lower levels of
IP-10 were induced by clinical strains than by laboratory strains in
both differentiated THP-1 and MDMs. The secretion of MIP-1α was
also depressed but only in the THP-1 cells infected with clinical
strains. This depressed chemokine secretion may hinder the movement of
Th-1 cells from the periphery into the infection foci to control the
infection. Correlation between IP-10 and IL-12p40 showed a negative
relationship in control MDMs, while there was a positive correlation in
all the infected strains, indicating their cooperative role in
attracting and activating Th1 cells for a protective immune response at
the site. This relationship was strain dependent, with avirulent H37Ra
showing higher correlation, followed by the clinical strains and the
virulent H37Rv. A positive correlation of IP-10 with IFN-Îł (S7 and
H37Ra) and with IL-10 (H37Ra and H37Rv) suggested a definitive
interplay of these molecules in infection. Conclusions: The chemokines
secretion by infected THP-1 cells and MDMs was strain dependant and the
lower induction by the clinical strains may indicate that the clinical
strains maintain a quiescent nature to mislead the host immune system
for their benefit