Spore Germination in Saccharomyces cerevisiae : transfer of wild type spores to rich (YPD) medium
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ABSTRACT: To study the signals and pathways underlying spore germination we examined the global changes in gene expression during this process. We find that the germination process can be divided into two distinct stages. During the first stage, the induced spores respond only to glucose. The transcription program during this stage recapitulates the general transcription response of yeast cells to glucose. Only during the second phase are the cells able to sense and respond to other nutritional components in the environment. Components of the mitotic machinery are involved in spore germination but in a distinct pattern. In contrast to the mitotic cell cycle, growth related events during germination are not coordinated with nuclear events and are separately regulated. Genome-wide expression profiling enables us to follow the progression of spore germination, thus dividing this process into two major stages and to identify germination-specific regulation of components of the mitotic cell cycle machinery. Keywords: Time course
Project description:To study the signals and pathways underlying spore germination we examined the global changes in gene expression during this process. We find that the germination process can be divided into two distinct stages. During the first stage, the induced spores respond only to glucose. The transcription program during this stage recapitulates the general transcription response of yeast cells to glucose. Only during the second phase are the cells able to sense and respond to other nutritional components in the environment. Components of the mitotic machinery are involved in spore germination but in a distinct pattern. In contrast to the mitotic cell cycle, growth related events during germination are not coordinated with nuclear events and are separately regulated. Genome-wide expression profiling enables us to follow the progression of spore germination, thus dividing this process into two major stages and to identify germination-specific regulation of components of the mitotic cell cycle machinery. Keywords: Time course
Project description:The process of Saccharomyces cerevisiae spore germination includes breakage of dormancy, morphological changes and resumption of vegetative growth. We have determined the global transcriptional response during the first two hours of spore germination in response to rich growth medium and glucose alone, and identified possible transcription factors regulating the different transcriptional programs.
Project description:The process of Saccharomyces cerevisiae spore germination includes breakage of dormancy, morphological changes and resumption of vegetative growth. We have determined the global transcriptional response during the first two hours of spore germination in response to rich growth medium and glucose alone, and identified possible transcription factors regulating the different transcriptional programs. Saccharomyces cerevisiae Y55 spores subjected to YPD and glucose 2%. Samples are taken in triplicates (except for glucose 0 min were duplicates were taken) in time course series after glucose and nutrient addition. Total of 18 samples. RNA from dormant spores was used as reference RNA for all microarrays.
Project description:Purpose:To identify the targets of TORC1 during spore germination in budding yeast Results:We obtained the transcriptomes of germinating spores in the presence and absence of rapamycin with and average Read Count = 14,009,863 and an Average Overall alignment: 95.23%. Differentialy expressed genes were identified by comparing the spore germination at various time points in the presence and absence of Rapamycin. Conclusions: Our transcriptomic analyses has revealed a role for TORC1 in regulating the glucose response genes
Project description:To gain insight into spore germination and outgrowth, the transcriptome changes during Bacillus subtilis spore conversion to vegetative cells were analyzed. The transcriptome analysis also allowed us to trace the different functional groups of genes expressed during this conversion. . Our analysis identified 34 abundant mRNA transcripts in the dormant spores, at least 31 of which were rapidly degraded after the phase transition and observed 3152 differentially expressed genes during spore germination and outgrowth.
Project description:Bacillus subtilis forms dormant spores upon nutrient depletion. Under favorable environmental conditions, the spore breaks its dormancy and resumes growth in a process called spore germination and outgrowth. To elucidate the physiological processes that occur during the transition of the dormant spore to an actively growing vegetative cell, we studied this process in a time-dependent manner by a combination of microscopy, analysis of extracellular metabolites and a genome-wide analysis of transcription. The results indicate the presence of abundant levels of late sporulation transcripts in dormant spores. In addition, results suggest the existence of a complex and well-regulated spore outgrowth program, involving the temporal expression of at least 30 % of the B. subtilis genome. Keywords: time course, spore outgrowth
Project description:Heat-treated spores show delayed and slower germination and outgrowth compared to untreated spores presumably due to spore damage repair. This study was performed to identify genes possibly involved in spore damage repair in B. cereus. In this study we compared the transcriptomic profiles of untreated and heat-treated spores during germination and outgrowth in BHI at 30C.
Project description:Description
Bacillus subtilis forms highly resistant, metabolically inactive spores upon nutrient limitation. These endospores pose challenges to the food and medical sectors. Spores reactivate their metabolism upon contact with germinants through germination and outgrowth, and then develop into vegetative cells. However, the mechanism of the activation of the molecular machinery that triggers spore germination and outgrowth is unclear. To gain further insight into spore germination and outgrowth, the transcriptome and proteome changes during Bacillus subtilis spore conversion to vegetative cells were analyzed. The transcriptome analysis also allowed us to trace the different functional groups of genes expressed during this conversion. For each time-point sampled, the change in the spore proteome was quantitatively monitored relative to the reference proteome of 15N metabolically labelled vegetative cells. Of the quantified proteins, 60 percent are common to vegetative cells and spores, indicating that spores have a minimal set of proteins sufficient for the resumption of metabolism upon completion of germination. The shared proteins thus represent the most basic survival kit for spore-based life. Until the phase transition, defined as the completion of germination, we observed no significant change in the proteome or the transcriptome. Our analysis identified 34 abundant mRNA transcripts in the dormant spores, at least 31 of which were rapidly degraded after the phase transition. We observed 3152 differentially expressed genes, and demonstrated with our mass spectrometry analyses the differential expression of 323 proteins. Our data show that 173 proteins from dormant spores, both proteins unique to spores and proteins shared with vegetative cells, are lost after completion of germination. Further analysis is required to functionally interpret the observed protein loss. The observed diverse timing of the synthesis of different protein sets reveals a putative core-strategy of the revival of life starting from the B. subtilis spore.
Project description:Sorbic acid (SA) is widely used as a preservative, but the effect of SA on spore germination and outgrowth has gained limited attention up to now. Therefore, the effect of sorbic acid on germination of spores of B. cereus strain ATCC 14579 was analyzed both at phenotype and transcriptome level. Spore germination and outgrowth was assessed at pH 5.5 without and with 0.75, 1.5 and 3.0mM (final concentrations) undissociated sorbic acid (HSA). This resulted in distinct HSA concentration-dependent phenotypes, varying from delays in germination and outgrowth to complete blockage of germination at 3.0mM HSA. The phenotypes reflecting different stages in the germination process could be confirmed using flow cytometry and could be recognized at transcriptome level by distinct expression profiles. In the absence and presence of 0.75 and 1.5mM HSA, similar cellular ATP levels were found up to the initial stage of outgrowth, suggesting that HSA-induced inhibition of outgrowth is not caused by depletion of ATP. Transcriptome analysis revealed the presence of a limited number of transcripts in dormant spores, outgrowth related expression, and genes specifically associated with sorbic acid stress, including alterations in cell envelope and multi-drug resistance. The potential role of these HSA-stress associated genes in spore outgrowth is discussed.
Project description:Rhizopus delemar is an invasive fungal pathogen, responsible for the frequently fatal disease mucormycosis. Germination, a crucial mechanism by which spores of Rhizopus delemar infect and cause disease, is a key developmental process that transforms the dormant spore state into a vegetative one. Understanding the molecular mechanisms which underpin this transformation may be key to controlling mucormycosis; however, the regulation of germination remains poorly understood. This study describes the transcriptional changes which take place over the course of germination.