We previously discovered that a diffusible signal (Rosette Inducing Factor 1; RIF-1) from the prey bacterium Algoriphagus machipongonensis (Phylum Bacteroidetes) regulates multicellular development in S. rosetta. we have identified and characterized the structure of the signaling molecule, which is a novel sulfonolipid. 

We previously discovered that a diffusible signal (Rosette Inducing Factor 1; RIF-1) from the prey bacterium Algoriphagus machipongonensis (Phylum Bacteroidetes) regulates multicellular development in S. rosetta. we have identified and characterized the structure of the signaling molecule, which is a novel sulfonolipid. 

Bacterial sphinogolipids as signaling molecules

We study a unique example of a eukaryotic-bacterial interaction in which diffusible signals from the prey bacteria Algoriphagus trigger the transition from single cells to colony development in the choanoflagellate Salpingoeca rosetta. Our goal is to elucidate the nature and function of the microbial signals that elicit morphogenic responses in choanoflagellates and how these signals impact the cell biology of other members of the microbial community. In collaboration with Christine Beemelmans (Max Plank Institute, Leibniz) and Dominic Campopiano (University of Edinburgh) and funded by the Victoria S. and Bradley L. Geist Foundation (PI: Alegado) and NSF IOS01558169 (PI: Alegado)


A CLOSE-UP IMAGE OF THE TUBEWORM HYDROIDES ELEGANS WITH ITS FEATHER-LIKE TENTACLES EXTENDED FROM ITS TUBE. THE TENTACLES BOTH COLLECT MICROSCOPIC FOOD PARTICLES FROM THE WATER AND SERVE AS THE PLACE FOR GAS EXCHANGE FOR THE WORM, PASSING CARBON DIOXIDE FROM THE WORM AND GAINING DISSOLVED OXYGEN FROM THE WATER. (CREDIT: BRIAN NEDVED)

A CLOSE-UP IMAGE OF THE TUBEWORM HYDROIDES ELEGANS WITH ITS FEATHER-LIKE TENTACLES EXTENDED FROM ITS TUBE. THE TENTACLES BOTH COLLECT MICROSCOPIC FOOD PARTICLES FROM THE WATER AND SERVE AS THE PLACE FOR GAS EXCHANGE FOR THE WORM, PASSING CARBON DIOXIDE FROM THE WORM AND GAINING DISSOLVED OXYGEN FROM THE WATER. (CREDIT: BRIAN NEDVED)

Bacterial basis of larval settlement

This effort will focus on questions relating to both bacterial cues that induce larvae to stop swimming, attach to a surface and undergo metamorphosis and larval response mechanisms, e.g., where on the larva does a bacterial “product” act to stimulate settlement, how is that signal perceived by a larva, and how does that stimulation result in the dramatic developmental events of metamorphosis? In collaboration with Mike Hadfield (Pacific Bioscience Research Center), Brian Nedved (PBRC), and Shugeng Cao (UH Hilo) and funded by the Gordon and Betty Moore Foundation. 


Progression of liver disease may be due, in part, to dysbiosis of the gut microbiota and production of deleterious co-metabolites

Progression of liver disease may be due, in part, to dysbiosis of the gut microbiota and production of deleterious co-metabolites

Gut microbiota mediated bile acid alterations in hepatic carcinogenesis

Uncovering the molecular mechanisms that link metabolic disruptions in gut microbial host co-metabolism to metabolic disorders and liver cancer. Deciphering the complex metabolic interactions in the gut-liver-brain axis. Collaborating with Wei Jia (UH Cancer Research Center) and funded by the National Cancer Institute (PI: Jia; co-PI; Alegado)


Photo Credit: Kiana Frank

Photo Credit: Kiana Frank

Diversity and Dynamics of Coastal Marine Microbes

Characterization of large-scale 16S rRNA gene libraries from stations in Heʻeia Coastal Oceans Observing System located in Heʻeia Fishpond. We are investigating the drivers of this diversity with a specific focus on microbial responses to disturbance and stressors including storm events. In collaboration with Paepae o Heʻeia, Margaret McManus, Kathleen Ruttenberg, Kiana Frank and Brian Glazer at UH Mānoa (Na Kilo Honua o Heʻeia). Funded by NOAA Sea Grant (PI: Alegado) and the USGS State Water Resources Resource Institute Program (PI: Alegado)

 


Microbial Responses to Land-based Sources of Pollution

Land-based sources of pollution (LBSP) drive coastal algal blooms, leading negative ecological and economic impacts, and are often exacerbated by declines in grazers or loss of habitat. Our goal is to identify areas vulnerable to blooms using American Samoa as comparison for on-going studies of the Main Hawaiian Islands. We selected coastal sites spanning a human use gradient ranging from pristine (no residents within the watershed, little LBSP, few obstructions to water movement and sparse run-off) to heavily impacted (downstream of dense residential areas with substantial sediment loads and slowed water movement) – pre-conditions for an algal bloom. Sampling surface water for inorganic nutrients, ∂15N, and planktonic microbial community,  tissues of indicator algae and characterization of the benthic community. In collaboration with Celia Smith (UH Manoa, Botany) and funded by the USGS Water Resources Resource Institute Program.


Overlapping historical records and climate proxies can extend climate reconstruction in Hawaiʻi beyond 150 years.

Overlapping historical records and climate proxies can extend climate reconstruction in Hawaiʻi beyond 150 years.

Kilo Lani: Observations of Climate Patterns in Historical Hawaiʻi

Our long-term goal is to use indigenous-based historical records to reconstruct Hawaiian regional climate beyond conventional instrument records. We employ 2 complementary strategies to develop a deeper understanding of how climate modes, such as ENSO, affected regional climates in Hawai’i: introducing additional historical observations through Hawaiian language newspapers and developing climate indicators specific to Hawai’i using introduced and native tree species.  This project is a collaboration with Axel Timmermann (Oceanography/Interactional Pacific Research Center) and Puakea Nogelmeier (Kawaihuelani Center for Hawaiian Language). Funded by the NOAA Joint Institute for Marine and Atmospheric Research and the USGS Pacific Island Climate Science Center (PI: Alegado)