Project description:BackgroundHoney bees are the principal commercial pollinators. Along with other arthropods, they are increasingly under threat from anthropogenic factors such as the incursion of invasive honey bee subspecies, pathogens and parasites. Better tools are needed to identify bee subspecies. Genomic data for economic and ecologically important organisms is increasing, but in its basic form its practical application to address ecological problems is limited.ResultsWe introduce HBeeID a means to identify honey bees. The tool utilizes a knowledge-based network and diagnostic SNPs identified by discriminant analysis of principle components and hierarchical agglomerative clustering. Tests of HBeeID showed that it identifies African, Americas-Africanized, Asian, and European honey bees with a high degree of certainty even when samples lack the full 272 SNPs of HBeeID. Its prediction capacity decreases with highly admixed samples.ConclusionHBeeID is a high-resolution genomic, SNP based tool, that can be used to identify honey bees and screen species that are invasive. Its flexible design allows for future improvements via sample data additions from other localities.
Project description:It is already well known that the immune cells called macrophages are involved in the mechanisms of heart failure (HF). Macrophages are divised into several subtypes based on behavior.Some subsets are highly inflammatory, while some support tissue repair. Recent studies have suggested that the classical M1/M2 classification is not suitable for some pathological processes of the heart. Single cell sequencing (scSeq) is an ideal tool to clarify the macrophage heterogeneity in HF. It provided a higher resolution of cellular differences and a better understanding of individual cell function. In this study, we aimed to identify a macrophage subset that linked with heart failure, and furtherly screen the target and investigate the mechanism.
Project description:Purpose: The gene molecular network involved in teleost fish sex determination and differentiation is highly variable among species and even in some cases among populations of the same species. The objectives of the present study were to identify the period of gonadal sex differentiation in tambaqui juveniles, as well as the genes and pathways potentially involved in this process. Methods: Histological analysis of juveniles was carried out to establish a timeline of the gonadal differentiation in tambaqui. Based on that knowledge, ten juveniles were selected before the first evidence of histological sex differentiation and total RNA was extracted from their trunks and used for RNA-Sequencing and a subsequent de novo transcriptome assembly. Principal Component Analysis (PCA) of the whole transcriptome data was used to cluster samples into two distinct groups: putative males and putative females. Differential gene expression, functional annotation and gene enrichment were used to identify genes and pathways related to sex differentiation in tambaqui to which was applied the Mann-Whitney non-parametric t test (p <0.05) confirming the statistical significance of the expression dimorphism between the groups. Results: The first sign of histological sex differentiation in tambaqui was the formation of the ovarian cavity detected in individuals measuring about 40 mm in total length. Before the differentiation period, components of the Wnt / β-catenin pathway, fox and fst genes (p <0.05) suggest female sex development in the putative females, whereas antagonistic pathways (gsk3b, wt1 and fgfr2), sox9 and genes for androgen synthesis (p <0.05) are indicative of a male-like differentiation. Conclusions: Tambaqui juveniles prior to the morphological ovarian differentiation present the Wnt / β-catenin pathway exerting putative role on the sex differentiation target, either upregulated in female-like individuals, or antagonized in male-like individuals. Thus, the present work provides a molecular basis for future studies on the application of tambaqui monosex cultivation.
Project description:The development of single-cell RNA-Sequencing (scRNA-Seq) has allowed high resolution analysis of cell type diversity and transcriptional networks controlling cell fate specification. To identify the transcriptional networks governing human retinal development, we performed scRNA-Seq over retinal organoid and in vivo retinal development, across 20 timepoints. Using both pseudotemporal and cross-species analyses, we examined the conservation of gene expression across retinal progenitor maturation and specification of all seven major retinal cell types. Furthermore, we examined gene expression differences between developing macula and periphery and between two distinct populations of horizontal cells. We also identify both shared and species-specific patterns of gene expression during human and mouse retinal development. Finally, we identify an unexpected role for ATOH7 expression in regulation of photoreceptor specification during late retinogenesis. These results provide a roadmap to future studies of human retinal development, and may help guide the design of cell-based therapies for treating retinal dystrophies.
Project description:The development of single-cell RNA-Sequencing (scRNA-Seq) has allowed high resolution analysis of cell type diversity and transcriptional networks controlling cell fate specification. To identify the transcriptional networks governing human retinal development, we performed scRNA-Seq over retinal organoid and in vivo retinal development, across 20 timepoints. Using both pseudotemporal and cross-species analyses, we examined the conservation of gene expression across retinal progenitor maturation and specification of all seven major retinal cell types. Furthermore, we examined gene expression differences between developing macula and periphery and between two distinct populations of horizontal cells. We also identify both shared and species-specific patterns of gene expression during human and mouse retinal development. Finally, we identify an unexpected role for ATOH7 expression in regulation of photoreceptor specification during late retinogenesis. These results provide a roadmap to future studies of human retinal development, and may help guide the design of cell-based therapies for treating retinal dystrophies.
Project description:The aim of this study is to identify a set of eye-specific genes across Drosophila species. Species are used as replicates to remove biological noise and identify a core set of conserved eye-developmental genes. We analyze this conserved core using the motif discovery tool i-cisTarget, and identify master regulators of retinal determination, including the Zinc Finger transcription factor Glass.
Project description:The full complement of molecular pathways contributing to Parkinson’s disease (PD) pathogenesis remains unknown. Here, to address this issue, we began by using a high-resolution variant of functional magnetic resonance imaging (fMRI) to pinpoint brainstem regions differentially affected by, and resistant to, the disease. Then, relying on the imaging information as a guide, we profiled gene expression levels of postmortem brain samples and used a factorial statistical model to identify a disease related decrease in the expression of the polyamine enzyme spermidine/spermine N1-acetyltransferase 1 (SAT1). Next, a series of studies were performed to confirm the pathogenic relevance of this finding. First, to test for a causal link between polyamines and α-synuclein toxicity, we investigated a yeast model expressing α-synuclein. Polyamines were found to enhance the toxicity of α-synuclein, and an unbiased genome-wide screen for modifiers of α-synuclein toxicity identified Tpo4, a member of a family of proteins responsible for polyamine transport. Second, to test for a causal link between SAT1 activity and PD histopathology we investigated a mouse model expressing α-synuclein. DENSPM (N1, N11-diethylnorspermine), a polyamine analog that increases SAT1 activity, was found to reduce PD histopathology, while Berenil (diminazene aceturate), a pharmacological agent that reduces SAT1 activity, worsened the histopathology. Third, we genotyped PD patients and controls and isolated a rare but novel variant in the SAT1 gene, although the functional significance of this genetic variant was not identified. Taken together, the results suggest that the polyamine pathway contributes to PD pathogenesis. Imaging-guided microarray In principle, gene expression profiling techniques like microarray are well suited to identify molecular pathways contributing to the pathogenesis of complex diseases. In practice, however, microarray applied to diseases of the brain present a number of analytic challenges. By identifying regions within the same brain structure that are differentially targeted by and resistant to a disease, imaging-guided microarray is an approach designed to address these limitations. Specifically, guided by the spatial information generated from high resolution functional imaging, a 2x2 factorial analysis-of-variance can be designed, including both within and between group factors, and this “double subtraction” model is effective in improving signal-to-noise in a microarray experiment. Relying on imaging findings, we harvested the DMNV from 6 postmortem brains with evidence of PD and from 5 control brains. The postmortem PD cases were evaluated for pathological changes (Lewy body-containing neurons and Lewy neurites evidenced with antibodies directed against α-synuclein aggregates) that matched the pattern proposed by Braak. We relied on the imaging results to identify a neighboring medullary region relatively unaffected by the disease to be used as a within-brain control. We decided on the inferior olivary nucleus (ION), because it is histologically identifiable, and harvested the ION from each of the 6 PD cases and 5 controls. Microarray techniques were used to generate gene expression profiles for each of the 22 tissue samples. A repeated-measures 2x2 factorial ANOVA model constructed for the imaging study was applied to the expression dataset, in which expression levels from two regions of the medulla (DMNV vs. ION) were included as the first within group factor, diagnosis (PD vs. controls) was the between group factor, and age and sex were included as covariates. Based on current literature, one of the top hits (SAT1) was investigated further to determine if it played a role in PD pathogenesis.
Project description:Competition is a major determinant of plant community structure consisting of both species-specific and general interactions, either of which may influence competitive competency and plant abundance and size. In certain cases, competitive competency could arise from altered gene expression and plant function when an individual is confronted with new competitors. We explored competition at the molecular level by hybridizing transcripts from Centaurea maculosa (spotted knapweed), one of North America's most invasive exotic plant species, to an Arabidopsis microarray chip. Centaurea was grown in competition with Festuca idahoensis (Idaho fescue), a native grass species that generally has weak competitive effects against Centaurea; Gaillardia aristata (Indian blanketflower), a native herbaceous species that tends to be a much stronger competitor against Centaurea; or alone (control). The expression of some genes was found to be relatively uninfluenced by the type of plant neighbor, whereas other patterns of gene expression appeared to be more neighbor specific. To our knowledge, these results are the first to identify genes in an invasive plant that are induced or repressed by plant neighbors and provide a new avenue of insight into the molecular aspects of plant competitive ability. Keywords: treated vs.untreated
Project description:Echinacea, native to the Canadian prairies and the prairie states of the United States, has a long tradition as a folk medicine for the Native Americans. Currently, Echinacea are among the top 10 selling herbal medicines in the U.S. and Europe, due to increasing popularity for the treatment of common cold and ability to stimulate the immune system. However, the genetic relationships within the species of this genus are unclear, which makes difficult the authentication of the species used for the medicinal industry. We report the construction of a novel Subtracted Diversity Array (SDA) for Echinacea species and demonstrate the potential of this array for isolating highly polymorphic sequences.