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Array-based transcriptional analysis of Clostridium sporogenes during germination, cell outgrowth and vegetative life

ABSTRACT: The members of the genus Clostridium, such as the other spore-forming anaerobic bacteria, have a complex and strictly regulated life-cycle but very little is known about genetic pathways involved at different stages. Clostridium sporogenes, Gram positive bacterium usually involved in food spoilage and frequently isolated from late blowed cheese is genetically indistinguishable from proteolytic Clostridium botulinum and is the non-neurotoxigenic counterpart often used as exemplar for the toxic subtypes. In this work we have performed a microscopy study combined with a custom array-based analysis of C. sporogenes cycle, from dormant spores to early stationary phase. We identified in spores a total of 211 transcripts validating the ipothesis that mRNAs are abundant and strikingly different from those present in growing cells. The spores transcripts included genes responsible of different life-sustaining functions, suggesting the theory of transcripts entrapment or of a basic poly-functional genes activation for future steps. In addition, after three hours from the beginning of the germination process, a 20% of the total up-regulated genes were temporally expressed in germinating spores. The vegetative condition appears to be the more active in terms of gene transcription and protein synthesis and also genes for germination and sporulation factors seem to be expressed at this point. These results suggest that spores are not silent entities and a wider knowledge about genetic pathways involved in Clostridium life cycle could be of help for a better understanding also of pathogenic clostridia types.

ORGANISM(S): Clostridium botulinum A str. ATCC 3502 Clostridium sporogenes

PROVIDER: GSE38619 | GEO | 2012/06/13

SECONDARY ACCESSION(S): PRJNA168434

REPOSITORIES: GEO

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Project description:The members of the genus Clostridium, such as the other spore-forming anaerobic bacteria, have a complex and strictly regulated life-cycle but very little is known about genetic pathways involved at different stages. Clostridium sporogenes, Gram positive bacterium usually involved in food spoilage and frequently isolated from late blowed cheese is genetically indistinguishable from proteolytic Clostridium botulinum and is the non-neurotoxigenic counterpart often used as exemplar for the toxic subtypes. In this work we have performed a microscopy study combined with a custom array-based analysis of C. sporogenes cycle, from dormant spores to early stationary phase. We identified in spores a total of 211 transcripts validating the ipothesis that mRNAs are abundant and strikingly different from those present in growing cells. The spores transcripts included genes responsible of different life-sustaining functions, suggesting the theory of transcripts entrapment or of a basic poly-functional genes activation for future steps. In addition, after three hours from the beginning of the germination process, a 20% of the total up-regulated genes were temporally expressed in germinating spores. The vegetative condition appears to be the more active in terms of gene transcription and protein synthesis and also genes for germination and sporulation factors seem to be expressed at this point. These results suggest that spores are not silent entities and a wider knowledge about genetic pathways involved in Clostridium life cycle could be of help for a better understanding also of pathogenic clostridia types. RNA was isolated from spores, germinating spores (3h), outgrowth/transitional mid-log vegetative cells and early stationary cells of Clostridium sporogenes UC9000 previously isolated from milk. There were 3 biological replicates (independent cultures) for each condition. Probes corresponding to 3400 genomic CDSs of C. botulinum A ATCC 3502 were synthesized in three replicates randomly distributed on the chip.

Project description:Spermatophyte pollen tubes and root hairs have been used as single-cell-type model systems toward understanding the molecular processes underlying polar growth of plant cells. Horsetail (Equisetum arvense L.) is a perennial herb species in Equisetopsida, which creates separately growing spring and summer stems in its life cycle. The mature chlorophyllous spores produced from spring stems can germinate without dormancy. Here we report the cellular features and protein expression patterns in five stages of horsetail spore germination (mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Using 2-DE combined with mass spectrometry, 80 proteins were found to be differentially expressed upon spore germination. Among them, proteins involved in photosynthesis, protein turnover, and energy supply were over-represented. Thirteen proteins appeared as isoforms on the gels, indicating the potential importance of post-translational modification. In addition, the dynamic changes of ascorbate peroxidase, peroxiredoxin, and dehydroascorbate reductase implied that reactive oxygen species homeostasis is critical in regulating cell division and tip-growth. The time course of germination and diverse expression patterns of proteins in photosynthesis, energy supply, lipid and amino acid metabolism indicated that heterotrophic and autotrophic metabolism were necessary in light-dependent germination of the spores. Twenty-six proteins were involved in protein synthesis, folding, and degradation, indicating that protein turnover is vital to spore germination and rhizoid tip-growth. Furthermore, the altered abundance of small G protein Ran1, 14-3-3 protein, actin, and Caffeoyl-CoA O-methyltransferase revealed that signaling transduction, vesicle trafficking, cytoskeleton dynamics, and cell wall modulation were critical to cell division and polar growth. These findings provide up-to-date evidences for understanding fern spore asymmetric division and rhizoid polar growth.

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.

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Array-based transcriptional analysis of Clostridium sporogenes during germination, cell outgrowth and vegetative life

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