Project description:The Lucinidae is a large family of marine bivalves. They occur in diverse habitats from shallow-water seagrass sediments to deep-sea hydrothermal vents. All members of this family so far investigated host intracellular sulfur-oxidizing symbionts that belong to the Gammaproteobacteria. We recently discovered the capability for nitrogen fixation in draft genomes of the symbionts of Loripes lucinalis from the Bay of Fetovaia, Elba, Italy. With proteomics, we investigated whether the genes for nitrogen fixation are expressed by the symbionts.
Project description:To determine the optimal RNA-Seq approach for animal host-bacterial symbiont analysis, we compared transcriptome bias, depth and coverage achieved by two different mRNA capture and sequencing strategies applied to the marine demosponge Amphimedon queenslandica holobiont, for which genomes of the animal host and three most abundant bacterial symbionts are available.
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:Many pathogens and symbionts contain multipartite genomes, but how they are stably maintained is poorly understood. The plant pathogen, Agrobacterium tumefaciens, contains four replicons. Recent work indicates that their replication origins cluster at cell poles in a manner that depends on their ParB-family centromeric proteins. Here, we provide evidence that centromeric clustering is mediated by interactions between these centromeric proteins. We further show that the disruption of centromere clustering results in the loss of replicons. Our data establish the role of centromeric clustering in multipartite genome maintenance.
Project description:The goal of this study was to use heterologous microarray hybridization to determine genomic content shared among different vesicomyid symbionts. These symbionts are closely related and can be thought of as different strains of bacteria, facilitating the use of heterologous microarray hybridization to determine genomic content. Keywords: comparative genomic hybridization
Project description:The goal of this study was to use heterologous microarray hybridization to determine genomic content shared among different vesicomyid symbionts. These symbionts are closely related and can be thought of as different strains of bacteria, facilitating the use of heterologous microarray hybridization to determine genomic content. Keywords: comparative genomic hybridization Microarrays were built off the Ruthia magnifica genome and two replicate hybridizations to this organism were used as a baseline for comparisons. Genomic DNA from two other vesicomyid symbionts (Calyptogena kilmeri and C. pacifica symbionts) was also hybridized to the array with three biological replicates for each sample.
