Heat induced changes in protein expression profiles of Norway spruce (Picea abies) ecotypes from different elevations

Although tree species typically exhibit low genetic differentiation between populations, ecotypes adapted to different environmental conditions can vary in their capacity to withstand and recover from environmental stresses like heat stress. Two month old seedlings of a Picea abies ecotype adapted to high elevation showed lower level of thermotolerance and higher level of tolerance to oxidative stress relative to a low elevation ecotype. Protein expression patterns following exposure to severe heat stress of the two ecotypes were compared by means of 2-DE. Several proteins exhibiting ecotype and tissue specific expression were identified by MS/MS. Among them, small heat shock proteins of the HSP 20 family and proteins involved in protection from oxidative stress displayed qualitative and quantitative differences in expression between the ecotypes correlated with the observed phenotypic differences. On the basis of these results, it can be speculated that the observed interpopulation polymorphism of protein regulation in response to heat stress could underlie their different capacities to withstand and recover from heat stress. These local adaptations are potentially relevant for the species adaptation to the conditions predicted by the current models for climate change

Life history shapes variation in egg composition in the blue tit Cyanistes caeruleus

Maternal investment directly shapes early developmental conditions and therefore has long-term fitness consequences for the offspring. In oviparous species prenatal maternal investment is fixed at the time of laying. To ensure the best survival chances for most of their offspring, females must equip their eggs with the resources required to perform well under various circumstances, yet the actual mechanisms remain unknown. Here we describe the blue tit egg albumen and yolk proteomes and evaluate their potential to mediate maternal effects. We show that variation in egg composition (proteins, lipids, carotenoids) primarily depends on laying order and female age. Egg proteomic profiles are mainly driven by laying order, and investment in the egg proteome is functionally biased among eggs. Our results suggest that maternal effects on egg composition result from both passive and active (partly compensatory) mechanisms, and that variation in egg composition creates diverse biochemical environments for embryonic development

Protein polymorphism between two Picea abies ecotypes as revealed by two-dimensional gel electrophoresis and tandem mass spectrometry

In species with high gene flow and consequent low interpopulation differentiation over wide geographic ranges, differential gene expression along ecological gradients often reveals adaptive significance. We investigated potential differences in protein expression between Picea abies ecotypes adapted to contrasting altitude conditions. Protein expression patterns were compared between needles and roots of 2-month-old P. abies seedlings by means of 2-dimensional electrophoresis. Proteins exhibiting differential expression between the 2 ecotypes were analyzed by tandem mass spectrometry. A total of 19 proteins exhibited qualitative or quantitative polymorphism between the 2 populations. These proteins exhibited organ-specific expression, and the level of interpopulation protein polymorphism was organ dependent. Among differentially expressed proteins, we identified proteins involved in photosynthesis, photorespiration, root tracheary element differentiation, and transmitochondrial membrane transport. Our results show that P. abies seedlings from locally adapted ecotypes exhibit consistent differences in protein expression. The expression polymorphism of some of these proteins has potential adaptive significance

NOX1 Supports the Metabolic Remodeling of HepG2 Cells

<div><p>NADPH oxidases are important sources of reactive oxygen species (ROS) which act as signaling molecules in the regulation of protein expression, cell proliferation, differentiation, migration and cell death. The NOX1 subunit is over-expressed in several cancers and NOX1 derived ROS have been repeatedly linked with tumorigenesis and tumor progression although underlying pathways are ill defined. We engineered NOX1-depleted HepG2 hepatoblastoma cells and employed differential display 2DE experiments in order to investigate changes in NOX1-dependent protein expression profiles. A total of 17 protein functions were identified to be dysregulated in NOX1-depleted cells. The proteomic results support a connection between NOX1 and the Warburg effect and a role for NOX in the regulation of glucose and glutamine metabolism as well as of lipid, protein and nucleotide synthesis in hepatic tumor cells. Metabolic remodeling is a common feature of tumor cells and understanding the underlying mechanisms is essential for the development of new cancer treatments. Our results reveal a manifold involvement of NOX1 in the metabolic remodeling of hepatoblastoma cells towards a sustained production of building blocks required to maintain a high proliferative rate, thus rendering NOX1 a potential target for cancer therapy.</p></div

NOX1 and ROS levels are decreased in HepG2 cells expressing shNOX1.

<p>NOX1 levels were determined by Western blot analysis in HepG2 cells stably expressing shRNA against NOX1 or a control shRNA. The image exemplifies a representative NOX1 Western blot. Relative protein expression is expressed as ratio between the Western blot intensity and total protein content of the sample determined from the PonceauS staining (left). Differences between groups were assessed using Welsch t-test (N_shCtr = 8, N_shNOX1 = 7). The dependence of the abundance of the dysregulated proteins upon NOX1 protein levels was tested in a mixed effect model with spot ID as random factor. ROS production was measured using CM-H2DCFDA assay (right). Differences in ROS levels between NOX1 reduced HepG2 cells and control cells were tested in a mixed effect model with cell type nested in replicates (N = 3).</p

NOX1 regulates glycogen content in HepG2 cells.

<p>Glycogen levels were assessed in HepG2 transiently transfected with two shRNAs against NOX1 or with control shRNA. NOX1 reduced HepG2 cells produce more glycogen than shCtr expressing cells (right). Differences in glycogen levels were tested in a linear mixed effect model with cell line as predictor and replicate (N = 4) as random factor (one-tailed post-hoc z test). NOX1 depletion was confirmed be Western blot analysis (left).</p

Abundance of differentially expressed proteins depends upon NOX1 relative expression (plotted are 95% CI).

<p>Abundance of differentially expressed proteins depends upon NOX1 relative expression (plotted are 95% CI).</p

Overview of the metabolic pathways regulated by NOX1.

<p>Proteins differentially expressed in control vs. NOX1 reduced HepG2 cells are involved in glucose, glutamine, nucleotide and lipid metabolism. α-KG—α-ketoglutarate, OAA—oxaloacetic acid, PEP—phosphoenolpyruvate, TAG—triacylglycerol, TCA cycle—tricarboxylic acid cycle.</p

2DE map displaying proteins differentially expressed in control vs. NOX1 reduced HepG2 cells.

<p>Empty arrows denote up-regulated protein functions, filled arrows denote down-regulated protein functions. White arrows denote differentially regulated but un-identified protein spots.</p