Project description:We used gene expression accompanied by physical characteristics and gill Na+/K+-ATPase activity to analyze physiological differences associated with two life history variations of juvenile fall Chinook Salmon in the Snake River basin. Subyearlings originating in the Snake River typically migrate seaward as subyearlings, whereas many subyearlings from the Clearwater River delay seaward migration during summer and complete seaward migration the following spring as yearlings. We examined gill Na+/K+-ATPase activity and gene expression of subyearlings at different times during rearing and seaward emigration. Natural-origin Snake River subyearlings rearing under an increasing photoperiod and seasonally increasing temperatures showed a typical increasing pattern of parr to smolt gill Na+/K+-ATPase activity development, which then declined into autumn. In contrast, Clearwater River subyearlings that had experienced cooler temperatures showed no pattern of increasing gill Na+/K+-ATPase activities and were not different from parr. Liver transcription of genes involved in DNA repair and binding, the cell cycle, metabolism (steroid, fatty acid and other metabolic pathways) iron homeostasis, heme and oxygen binding, the immune response, and male sexual development were enriched amongst genes differentially expressed between Snake River parr versus smolts. Gene expression results confirmed that Clearwater River subyearlings were parr-like in their physiological status. By autumn, subyearlings had low gill Na+/K+-ATPase activities despite their large size and external smolt characteristics. We suggest that environmental factors like temperature and photoperiod influence subyearling physiological status in each river that ultimately dictates juvenile life history pathways.
Project description:We used gene expression accompanied by physical characteristics and gill Na+/K+-ATPase activity to analyze physiological differences associated with two life history variations of juvenile fall Chinook Salmon in the Snake River basin. Subyearlings originating in the Snake River typically migrate seaward as subyearlings, whereas many subyearlings from the Clearwater River delay seaward migration during summer and complete seaward migration the following spring as yearlings. We examined gill Na+/K+-ATPase activity and gene expression of subyearlings at different times during rearing and seaward emigration. Natural-origin Snake River subyearlings rearing under an increasing photoperiod and seasonally increasing temperatures showed a typical increasing pattern of parr to smolt gill Na+/K+-ATPase activity development, which then declined into autumn. In contrast, Clearwater River subyearlings that had experienced cooler temperatures showed no pattern of increasing gill Na+/K+-ATPase activities and were not different from parr. Liver transcription of genes involved in DNA repair and binding, the cell cycle, metabolism (steroid, fatty acid and other metabolic pathways) iron homeostasis, heme and oxygen binding, the immune response, and male sexual development were enriched amongst genes differentially expressed between Snake River parr versus smolts. Gene expression results confirmed that Clearwater River subyearlings were parr-like in their physiological status. By autumn, subyearlings had low gill Na+/K+-ATPase activities despite their large size and external smolt characteristics. We suggest that environmental factors like temperature and photoperiod influence subyearling physiological status in each river that ultimately dictates juvenile life history pathways. Non-migrating and migrating natural subyearling fall Chinook salmon were collected from the Snake River. Non-migrating natural subyearling fall Chinook salmon were collected from the Clearwater River. Twelve fish were collected at each of four different time points for a total of 48 fish. Total RNA was extracted from the liver of each fish. Equal amounts of RNA from three fish were pooled to create four pools of RNA per time point. Each RNA pool was hybridized to an array for a total of 16 arrays with four arrays per time point.
Project description:Transcriptional profiling of Rhodopseudomonas palustris (R. palustris) comparing cbbT1 over-expressing strain with cbbT2 over-expressing strain. Goal was to discriminate the molecular mechanisms between transketolase I (cbbT1) and transketolase II (cbbT2). R.palustris is a purple non-sulfur anoxygenic phototrophic bacterium and transketolase (cbbT1 and cbbT2) is a key enzyme involved in the CBB cycle. Here, we investogated the functions of transketolase isoforms I (cbbT1) and II (cbbT2) in R. palustris through transcriptional profiling and other functional assays.
Project description:Throughout prehistory, human groups inhabited the Scheldt basin in northern Belgium, though few prehistoric human remains have been found there compared to the Meuse basin, where many caves contain human remains from various prehistoric phases. The limited preservation in the Scheldt basin is due to the region's high soil acidity, decalcification, and dryness, which degrade bones. The oldest known human bone is a clavicle dated to around 5790 years ago. Until recently, little effort had been made to identify human remains in the Scheldt basin. However, a recent survey identified four additional sites with prehistoric human remains. The paper aims to document these findings and explore their radiocarbon dates to better understand the region’s occupation history. The scarcity of remains before the Neolithic is attributed to taphonomic factors, and the lack of Late Neolithic remains might indicate a population decline, though flint mines and Meuse basin burials suggest otherwise. Another possibility is a shift in burial practices, with collective burials in megaliths or caves becoming common in western Europe during this time, unsuitable for the wet floodplains of the Scheldt basin. Most of the human bones discovered in the Scheldt basin were found in secondary contexts, likely displaced by fluvial activity. The bones were retrieved from former river channels and gullies, complicating interpretations of whether they originated from primary graves or were part of secondary burial practices. The absence of defleshing marks suggests the bones were not part of secondary burial rites, pointing instead to the erosion of primary graves from earlier settlements. The presence of settlement debris, including pottery and stone tools, supports this theory
Project description:Transcriptional profiling of Rhodopseudomonas palustris (R. palustris) comparing cbbT1 over-expressing strain with cbbT2 over-expressing strain. Goal was to discriminate the molecular mechanisms between transketolase I (cbbT1) and transketolase II (cbbT2). R.palustris is a purple non-sulfur anoxygenic phototrophic bacterium and transketolase (cbbT1 and cbbT2) is a key enzyme involved in the CBB cycle. Here, we investogated the functions of transketolase isoforms I (cbbT1) and II (cbbT2) in R. palustris through transcriptional profiling and other functional assays. Four-condition experiment, cbbT1 over-expressing cells, cbbT2 over-expressing cells, Negative control strain with empty plasmid, Wild type strain.
Project description:The purple sulfur bacterium Allochromatium vinosum DSM 180T is one of the best studied sulfur-oxidizing anoxygenic phototrophic bacteria and has been developed into a model organism for laboratory-based studies of oxidative sulfur metabolism. Here, we took advantage of the organism’s high metabolic versatility and performed whole-genome transcriptional profiling to investigate the response of A. vinosum cells upon exposure to sulfide, thiosulfate, elemental sulfur or sulfite as compared to photoorganoheterotrophic growth on malate. Differential expression (at least twofold) of 1149 genes was observed, corresponding to 30% of the A. vinosum genome. A total of 549 genes were identified for which relative transcription increased at least twofold during growth on one of the different sulfur sources while relative transcription of 599 genes decreased. A significant number of genes that were strongly induced have documented sulfur-metabolism-related functions. Among these are the dsr genes including dsrAB for dissimilatory sulfite reductase and the sgp genes for the proteins of the sulfur globule envelope thus confirming former results. In addition we were able to identify new genes encoding proteins with appropriate subcellular localization and properties to participate in oxidative dissimilatory sulfur metabolism. Two of these were chosen for inactivation and phenotypic analyses of the respective mutant strains. This approach verified the importance of the encoded proteins for the oxidation of sulfide and thereby also documented the suitability of comparative transcriptomics for the identification of new sulfur-related genes in anoxygenic phototrophic sulfur bacteria.
Project description:The purple sulfur bacterium Allochromatium vinosum DSM 180T is one of the best studied sulfur-oxidizing anoxygenic phototrophic bacteria and has been developed into a model organism for laboratory-based studies of oxidative sulfur metabolism. Here, we took advantage of the organism’s high metabolic versatility and performed whole-genome transcriptional profiling to investigate the response of A. vinosum cells upon exposure to sulfide, thiosulfate, elemental sulfur or sulfite as compared to photoorganoheterotrophic growth on malate. Differential expression (at least twofold) of 1149 genes was observed, corresponding to 30% of the A. vinosum genome. A total of 549 genes were identified for which relative transcription increased at least twofold during growth on one of the different sulfur sources while relative transcription of 599 genes decreased. A significant number of genes that were strongly induced have documented sulfur-metabolism-related functions. Among these are the dsr genes including dsrAB for dissimilatory sulfite reductase and the sgp genes for the proteins of the sulfur globule envelope thus confirming former results. In addition we were able to identify new genes encoding proteins with appropriate subcellular localization and properties to participate in oxidative dissimilatory sulfur metabolism. Two of these were chosen for inactivation and phenotypic analyses of the respective mutant strains. This approach verified the importance of the encoded proteins for the oxidation of sulfide and thereby also documented the suitability of comparative transcriptomics for the identification of new sulfur-related genes in anoxygenic phototrophic sulfur bacteria.