Project description:Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here, we operated two laboratory-scale sequence batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal (EBPR). Reactors formed two distinct biofilms, a floccular biofilm, consisting of small, loose, microbial aggregates, and a granular biofilm, forming larger, dense, spherical aggregates. Using metaproteomic methods we investigated the proteomic differences between these two biofilm communities, identifying a total of 2022 unique proteins. Both biofilms contained proteins that were indicative of core EBPR metabolisms and cellular function. To understand the proteomic differences between floccular and granular biofilm communities, we compared protein abundances that were statistically enriched in both biofilm states (alpha level = 0.05). Floccular biofilms were enriched with pathogenic secretion systems suggesting a previously unrecognized, highly competitive, mixed microbial community. Comparatively, granular biofilms revealed a high stress environment with evidence of nutrient starvation, phage predation pressure, extracellular polymeric substance (EPS) synthesis, and increased cell lysis. Granular biofilms enriched outermembrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement core EBPR metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter–enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability.
Project description:As a species mostly planted in tropical and subtropical regions, rice is sensitive to chilling temperature, especially at reproductive stage. However, the effect of low temperature on seed development has not been well characterized. The transcriptome of two rice cultivars Zhonghua11 and Hanfeng were analyzed to characterize the gene regulatory networks of rice seed during low temperature treatment. Whole plants of two rice cultivars Zhonghua11 (low temperature sensitive) and Hanfeng (low temperature tolerance) were treated at 14°C for 2 days during seed development stage. The plants without treatment serve as controls. Rice seeds were harvested for RNA extraction.
Project description:Banana is an important tropical fruit with high value. One main specie (cultivar Cavendish) is susceptible to low temperature, another close relative specie (Dajiao), considerably higher cold tolerance than Cavendish. Our previous global proteomics results suggested that some membrane proteins be likely involved in cold tolerance of Dajiao via antioxidation mechanism. To further investigate early cold stress response of Dajiao, we applied comparative membrane proteomics analysis for both cold-sensitive Cavendish and cold-tolerant Dajiao subjected to 10 °C for 0, 3 and 6 h.
Project description:Transcriptional profiling of the digestive gland tissue of female mussel Mytilus galloprovincialis exposed to copper along with a temperature gradient Background: Global warming is a major factor that may affect biological organization, especially in marine ecosystems and in coastal areas that are particularly subject to anthropogenic pollution. We evaluated the effects of simultaneous changes in temperature and copper concentrations on lysosomal membrane stability of the blue mussel Mytilus galloprovincialis (Lam.). Temperature and copper exerted additive effects on lysosomal membrane stability, exacerbating the toxic effects of metal cations present in non-physiological concentrations. Mussel lysosomal membrane stability was positively related toscope for growth, indicating possible effects of increasing temperature on mussel populations in metal-polluted areas. To clarify the molecular response to environmental stressors, we used a cDNA microarray with 1,700 sequences to measure the relative transcript abundances in the gills of mussels exposed to copper (40µg/L) and a temperature gradient (16°C, 20°C, and 24°C). In animals exposed only to heat stress, hierarchical clustering of the microarray data revealed three main clusters, which were largely dominated by down-regulation of translation-related differentially expressed genes, drastic up-regulation of folding protein-related genes, and genes involved in chitin metabolism. The response of mussels exposed to copper at 24° C was characterized by an opposite pattern of the genes involved in translation, most of which were up-regulated, as well asthe down-regulation of genes encoding heat shock proteins and microtubule-based movement proteins. Our data provide novel information on the transcriptomic modulations in mussels facing temperature increases and high copper concentrations; these data highlight the risk of marine life exposed to toxic chemicals in the presence of temperature increases due to climate change. Digestive gland tissue from individual animals in different experimental conditions were analyzed in a complete loop design. Dual color competitive hybridizations (Control “16°C” vs “20°C” vs “24°C” vs “16°C+Cu”, “20°C” vs “24°C” vs “20°C+Cu”, “24°C” vs “24°C+Cu”, “16°C+Cu” vs”20°C+Cu” vs “24°C+Cu”; “20°C+Cu” vs “24°C+Cu”) including label swap. Single individuals. Four biological replicates. One replicate per array.
Project description:Environmental stress is detrimental to cell viability and requires an adequate reprogramming of cellular activities to maximize cell survival. We present a global analysis of the response of Escherichia coli to acute heat and osmotic stress. We combine deep sequencing of total mRNA and ribosome-protected fragments to provide a genome-wide map of the stress response at transcriptional and translational level. For each type of stress, we observe a unique subset of genes that shape the stress-specific response. Upon temperature upshift, mRNAs with reduced folding stability up- and downstream of the start codon, and thus with more accessible initiation regions, are translationally favoured. Conversely, osmotic upshift causes a global reduction of highly-translated transcripts with high copy numbers, allowing reallocation of translation resources to undegraded and newly synthesised mRNAs Comparing global transcriptional and translational control by mRNA-Seq and Ribosome Profiling (mRNA-Seq of ribosome protected fragments – RPF)