The behavior of yeast cells during industrial processes such as the production of beer, wine and bioethanol has been extensively studied. By contrast, our knowledge about yeast physiology during solid state processes, such as bread dough, cheese or cocoa fermentation remains limited. We investigated changes in the transcriptome of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress response. Further analysis shows that genes regulated by the High Osmolarity Glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress, and that a proper induction of the HOG pathway is critical for an optimal fermentation.
Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.
No sample metadata fields
View SamplesTranscriptome of S. cerevisiae in shifts between glucose and maltose media with different re-growth conditions Overall design: Cells are pregrown in maltose, then grown for different durations in glucose and then washed back to maltose
A new protocol for single-cell RNA-seq reveals stochastic gene expression during lag phase in budding yeast.
Subject
View SamplesWhen grown on solid substrates, different microorganisms often form colonies with very specific morphologies. Whereas the pioneers of microbiology often used colony morphology to discriminate between species and strains, the phenomenon has not received much recent attention. In this study, we use a genome-wide assay in the model yeast Saccharomyces cerevisiae to identify all genes that affect colony morphology. We show that several major signaling cascades, including the MAPK, TORC, SNF1 and RIM101 pathways play a role, indicating that morphological changes are a reaction to changing environments. Other genes that affect colony morphology are involved in protein sorting and epigenetic regulation. Interestingly, the screen reveals only few genes that are likely to play a direct role in establishing colony morphology, one notable exception being FLO11, a gene encoding a cell-surface adhesin that has already been implicated in colony morphology, biofilm formation, and invasive and pseudohyphal growth. Using a series of modified promoters to tune FLO11 expression, we confirm the central role of Flo11 and show that differences in FLO11 expression result in distinct colony morphologies. Together, our results provide a first comprehensive looks at the complex genetic network that underlies the diversity in the morphologies of yeast colonies.
Identification of a complex genetic network underlying Saccharomyces cerevisiae colony morphology.
No sample metadata fields
View SamplesIn response to elevated glucocorticoid levels, erythroid progenitors rapidly expand to produce large numbers of young erythrocytes. Previous work demonstrates hematopoietic changes in rodents exposed to various physical and psychological stressors, however, the effects of chronic psychological stress on erythropoiesis has not be delineated. We employed laboratory, clinical and genomic analyses of a murine model of chronic restraint stress (RST) to examine the influence of psychological stress on erythropoiesis. Mice exposed to RST demonstrated markers of early erythroid expansion involving the glucocorticoid receptor. In addition, these RST-exposed mice had increased numbers of circulating reticulocytes and increased erythropoiesis in primary and secondary erythroid tissues. Mice also showed increases in erythroid progenitor populations and elevated expression of the erythroid transcription factor KLF1 in these cells. Together this work describes some of the first evidence of psychological stress affecting erythroid homeostasis through glucocorticoid stimulation and begins to define the transcription factor pathway involved.
Chronic restraint stress upregulates erythropoiesis through glucocorticoid stimulation.
Sex
View SamplesDifferential gene expression in preimplantation embryos has been documented, but few focused studies have been done to compare differential expression in human embryos after embryonic genome activation and specifically how they relate to blastocyst development. We hypothesized that blastocyst stage embryos would differentially express genes in pathways important in cell division, mobilization, and processes important in embryo implantation including endometrial apposition, adhesion, and invasion. We analyzed gene expression in 6 preimplantation human embryos.
Differentially expressed genes in preimplantation human embryos: potential candidate genes for blastocyst formation and implantation.
Specimen part
View SamplesThe ETS1 transcription factor is required for the development and cytokine-induced expansion of ILC2
The ETS1 transcription factor is required for the development and cytokine-induced expansion of ILC2.
Specimen part
View SamplesInverse and erythrodermic psoriasis are rare subtypes of psoriasis. Whereas the former is characterized by shiny erythematous non-scaly plaques in the body folds, the latter has widespread redness with fine scale, covering over 80% of the body-surface area, and can be life-threatening. Both are considered to be clinical subtypes of chronic plaque psoriasis, and often co-exist or evolve from plaque psoriasis (Boyd and Menter, 1989; Omland and Gniadecki, 2015), but the pathogenic mechanisms involved are unknown, and current treatments are frequently unsatisfactory. To assess shared and unique processes between chronic plaque, inverse, and erythrodermic psoriasis we analyzed archived formalin-fixed paraffin-embedded biopsies of clinically and histologically confirmed chronic plaque (n=12), inverse (n=40) and erythrodermic psoriasis cases (n=30) and healthy control skin (n=20) using Affymetrix ST 2.1 Arrays. Compared with healthy skin, psoriatic plaque lesions yielded 2450 differentially expressed genes (DEGs) (FDR, p<0.05), inverse psoriasis lesions yielded 408 DEGs (FDR, p<0.05) and erythrodermic psoriasis lesions yielded 447 DEGs (FDR, p<0.05). In total 294 genes were found to be shared among the three disease subtypes (FDR, p<0.05). While the overlap only accounted for 12% of the DEGs in chronic plaque psoriasis, it accounted for 66% and 72% of DEGs in erythrodermic and inverse psoriasis respectively.
IL-17 Responses Are the Dominant Inflammatory Signal Linking Inverse, Erythrodermic, and Chronic Plaque Psoriasis.
Specimen part, Disease, Disease stage
View SamplesGeneralized pustular psoriasis (GPP) is a rare, debilitating, and often life-threatening inflammatory disease characterized by episodic infiltration of neutrophils into the skin, pustule development, and systemic inflammation, which can manifest in the presence or absence of chronic plaque psoriasis (PV). Current treatments are unsatisfactory thus a better understanding the pathogenesis of GPP is warranted. To assess the pathophysiological differences between GPP and PV we performed a gene expression study on formalin-fixed paraffin-embedded biopsies of GPP (n=30) and PV (n=12) lesions and healthy control (n=20) skin. Compared with healthy skin, GPP lesions yielded 365 and PV 898 differentially expressed genes respectively, with 190 upregulated in both diseases. We detected higher expression of IL-1 and IL-36 cytokines in GPP lesions compared with PV, and this occurred proximal to neutrophils. We show both activated neutrophils and isolated neutrophil proteases can activate IL-36. Diverging from the Th1/Th17 pathophysiology of PV, significantly fewer IL23A, IL17A, IFNG, CXCL9, CXCL10 and MX1 transcripts were detected in GPP lesions. Our data indicate a level of sustained activation of IL-1 and IL-36 in GPP, inducing neutrophil chemokine expression, infiltration and pustule formation, suggesting that the IL-1 and IL-36 inflammatory axes are the main drivers of disease pathology in GPP.
IL-17 Responses Are the Dominant Inflammatory Signal Linking Inverse, Erythrodermic, and Chronic Plaque Psoriasis.
Specimen part
View SamplesThe clinical features of psoriasis, characterized by sharply demarcated scaly erythematous plaques, are typically so distinctive that a diagnosis can easily be made on these grounds alone. However, there is great variability in treatment response between individual patients, and this may reflect heterogeneity of inflammatory networks driving the disease. In this study, whole-genome transcriptional profiling was used to characterize inflammatory and cytokine networks in 62 lesional skin samples obtained from patients with stable chronic plaque psoriasis. We were able to stratify lesions according to their inflammatory gene expression signatures, identifying those associated with strong (37% of patients), moderate (39%) and weak inflammatory infiltrates (24%). Additionally, we identified differences in cytokine signatures with heightened cytokine-response patterns in one sub-group of lesions (IL-13-strong; 50%) and attenuation of these patterns in a second sub-group (IL-13-weak; 50%). These sub-groups correlated with the composition of the inflammatory infiltrate, but were only weakly associated with increased risk allele frequency at some psoriasis susceptibility loci (e.g., REL, TRAF3IP2 and NOS2). Our findings highlight variable points in the inflammatory and cytokine networks known to drive chronic plaque psoriasis. Such heterogeneous aspects may shape clinical course and treatment responses, and can provide avenues for development of personalized treatments.
Heterogeneity of inflammatory and cytokine networks in chronic plaque psoriasis.
Specimen part, Treatment
View SamplesPsoriasis is a chronic inflammatory skin disease characterized by marked proliferation of keratinocytes leading to pronounced epidermal hyperplasia, elongation of rete ridges and hyperkeratosis. The most common form of psoriasis, chronic plaque psoriasis (Psoriasis vulgaris), involves relatively stable occurrence and progression of sharply demarcated lesions, usually on the trunk and extremities, which share a combination of trademark histological features, including tortuous and dilated dermal capillaries, loss of the epidermal granular layer, and accumulation of neutrophils beneath parakeratotic scale. In this study, whole-genome transcriptional profiling was used to characterize gene expression in 4 lesional and uninvolved skin samples obtained from patients with stable chronic plaque psoriasis.Skin mRNA expression was analysed by microarray.
Heterogeneity of inflammatory and cytokine networks in chronic plaque psoriasis.
Specimen part, Subject
View Samples