Project description:Animal-algal photosymbioses are a unique group of symbiotic relationships in which animals harbor photosynthetic algae within their cells and tissues. Both marine and freshwater sponges host algal endosymbionts. In previous work, we demonstrated that freshwater sponges can acquire these endosymbionts horizontally through algal infection and that potentially conserved evolutionary pathways may lead to the establishment of the endosymbioses including those involved in endocytosis, ion transport, vesicle-mediated transport, innate immunity, redox regulation, and metabolic processes. Here, we show that algal symbionts can be transferred vertically from algal-bearing overwintering gemmules to adult sponges, and that their proliferation is enhanced by light. Sponges grown under light conditions harbored higher algal loads than those in the dark; however, algae were still able to proliferate and persist in sponges reared in the dark, occupying similar spatial locations to those grown in light. RNA-Seq analysis of algal-bearing sponges across developmental stages in light and dark conditions revealed genetic regulatory pathways involved in the transmission and establishment of the endosymbiosis. Differential expression analysis indicated that the endocytosis and SNARE pathways regulate the internalization and transport of algae at the earliest stage of hatching under light conditions and later in development under dark conditions, potentially contributing to the recruitment of endosymbiotic algae. In sponges hatched in the dark, genes involved in vesicle acidification are regulated, alongside changes in the expression of genes in the pentose phosphate pathway - a key metabolic route involved in redox homeostasis and circadian rhythm regulation via NADPH metabolism, is observed. E. muelleri serves as a versatile model system, supported by robust genomic and transcriptomic resources, for studying host-symbiont interactions. It offers a unique opportunity to investigate the molecular signaling and environmental factors that shape symbiosis in a system where the host can exist with or without algal endosymbionts, symbionts can be acquired either horizontally or vertically, and proliferation of the algae can occur with or without photosynthesis.
Project description:In order to understand how Phormidium mats establish, and the role of associated taxa in their development, we collected biofilms over a 19-day growth period during a nitrate-induced bloom event in the Wai-iti River for proteogenomics analysis. At the onset of a late summer bloom, cobbles from the Wai-iti River (Nelson, New Zealand) were removed, cleared of incipient growth with sterile sponges, and placed back into the river. Clearing was gentle as seeding from the pre-existing rock surface is important for bloom establishment [24]. Five pre-cleared cobbles were collected at each of 3 time points to capture the first 3, 6 and 9 days of growth (Table S1). Additional cobbles that contemporaneously developed biofilms were collected at days 12 and 19.
Project description:This study was designed to measure expressional profile induced by temporal treatment with Scutellaria baicalensis in HepG2 cells. Time-dependent expression of genes by treatment of Scutellaria baicalensis was measured on HepG2 cells. Total RNA was isolated and was subject to single channnel microarray.
