Project description:Floral nectar proteins (nectarins) are mainly enzymes and play important roles in inhibiting microbial growth in nectar and tailoring nectar chemistry before or after secretory. Nectar proteomes are usually small, but only very few plant species have had their nectar proteomes thoroughly investigated. Nectarins from Nicotiana tabacum (NT) were separated using two-dimensional gel electrophoresis, and then analyzed using mass spectrometry. Glycoproteins were isolated from raw NT nectar, separated by SDS-PAGE, and identified by mass spectrometry. All eight identified nectarins and four invertase genes’ expression were analysed by qPCR. Sugars composition, total sugar concentration, protein content, polyphenol content and hydrogen peroxide content were compared at different time intervals in extracted nectar and nectar in situ after secretion. Totally, eight nectarins were detected in NT nectar in which only two are glycoproteins, beta-xylosidase and a protein with unknown function. All of the eight nectarin genes expression was not nectary-specific and not synchronous along with the nectary development. After secretion, NT nectar in flower tube changed from sucrose–rich to hexose-rich type even though no free invertase or its activity was detected in NT nectar. No sugar composition changes observed in extracted nectar after incubating at 30 ℃ up to 48 hours in plastic tubes. Our results indicate that nectar post-secretory changes could be a complex process and tissue closely contact with nectar might function in it.
Project description:Floral nectar plays important roles in the interaction between animal-pollinated plants and pollinators. Growing empirical evidence shows that most of the proteins secreted in nectar (nectarins) are enzymes that can tailor nectar chemistry for their animal mutualists or reduce the growth of microorganisms in nectar. However, to date, the function of many nectarins remains unknown, and very few plant species have had their nectar proteome thoroughly investigated. Mucuna sempervirens (Fabaceae) is a perennial woody vine native to China. Nectarins from this species were separated using two-dimensional gel electrophoresis, and analyzed using mass spectrometry. A L-gulonolactone oxidase like protein (MsGulLO) was detected. MsGulLO has high similarity to L-gulonolactone oxidase 5 (AtGulLO5) in Arabidopsis thaliana, which was suggested to be involved in the pathway of ascorbate biosynthesis; however both MsGulLO and AtGulLO5 are divergent from animal L-gulonolactone oxidases. MsGulLO is suggested to function in hydrogen peroxide generation in nectar but not in plant ascorbate biosynthesis.
Project description:Mutations in the acid β-glucocerebrosidase (GBA1) gene, responsible for the lysosomal storage disorder Gaucher’s disease (GD), are the strongest genetic risk factor for Parkinson’s disease (PD) known to date. To elucidate the mechanisms underlying neurodegeneration in these patients, we generated induced pluripotent stem cells from subjects with GD and PD harboring GBA1 mutations and differentiated them to midbrain dopaminergic neurons. Highly enriched neurons showed a reduction of glucocerebrosidase activity and protein levels, increased glucosylceramide and α-synuclein levels and autophagic/lysosomal defects. Quantitative proteomics profiling revealed an increase of the neuronal calcium-binding protein 2 (NECAB2) in diseased neurons. We found dysregulation of calcium homeostasis and increased vulnerability to stress responses involving elevation of cytosolic calcium in mutant neurons. Importantly, correction of the mutations rescued such pathological phenotypes. Our findings provide evidence for a link between GBA1 mutations and complex changes in autophagic/lysosomal system and intracellular calcium homeostasis, which underlie vulnerability to neurodegeneration.
Project description:Mammals differ more than hundred fold in maximum lifespan, which can be altered in either direction during evolution, but the molecular basis for natural changes in longevity is not understood. Divergent evolution of mammals also led to extensive changes in gene expression within and between lineages. To understand the relationship between lifespan and variation in gene expression, we carried out RNA-seq-based gene expression analyses of liver, kidney and brain of 33 diverse species of mammals. Our analysis uncovered parallel evolution of gene expression and lifespan, as well as the associated life history traits, and identified the processes and pathways involved. These findings provide direct insights into how Nature reversibly adjusts lifespan and other traits during adaptive radiation of lineages. RNA-seq gene expression profiling in normal liver, kidney and brain of 33 mammalian species.
Project description:Spatial regulation analysis across multiple condition comparisons revealed distinct patterns of gene expression. We combined these transcriptome data with spatial CNS data to produce the spatio-transcripto map of the ganglia chain. The Hirudo Medicinalis set of transcripts generated here provides a resource for gene discovery and gene regulation within the nervous system. In addition, the strategy for de novo assembly of transcriptome data presented here may be helpful in other similar transcriptome studies. Examination of 3 different ganglia in 3 different leeches.
Project description:Many long-lived species of animals require the function of adult stem cells throughout their lives. However, the transcriptomes of stem cells in invertebrates and vertebrates have not been compared, and consequently ancestral regulatory circuits that control stem cell populations remain poorly defined. In this study, we have used data from high-throughput RNA sequencing (RNA-Seq) to compare the transcriptomes of pluripotent adult stem cells from planarians with the transcriptomes of human and mouse pluripotent embryonic stem cells. From a stringently-defined set of 4,432 orthologs shared between planarians, mice and humans, we identified 123 conserved genes that are ≥ 5-fold differentially expressed in stem cells from all three species. Guided by this gene set, we used RNAi screening in adult planarians to discover novel stem cell regulators, which we found to affect the stem cell-associated functions of tissue homeostasis, regeneration, and stem cell maintenance. Examples of genes that disrupted these processes included the orthologs of TBL3, PSD12, TTC27, and RACK1. From these analyses, we concluded that by comparing stem cell transcriptomes from diverse species, it is possible to uncover conserved factors that function in stem cell biology. These results provide insights into which genes composed the ancestral circuitry underlying the control of stem cell self-renewal and pluripotency. Three planarian tissues were analyzed: stem cells, stem cell progeny, and differentiated tissues. For the manuscript: Labbe, RM, et. al., 2012, Stem Cells