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Marine Chemical Ecology

Head of the Lab: Dr. Daniel Sher

@ the University of Haifa

2

Chemically mediated communication, eavesdropping, deceit and death in the sea

The Marine Chemical Ecology lab is looking for advanced students (MSc/PhD). For more details click here

Dr. Daniel Sher  Daniel Chemical ecology and microbial oceanography +972-4-8240731 dsher@univ.haifa.ac.il
Dr. Dikla Aharonovich  Dikla Marine microbial interactions, at the physiological, biochemical and genomic levels +972-4-8288961 daharon1@univ.haifa.ac.il
Dr. Dalit Roth-Rosenberg  Dalit Molecular and genetics markers for identification of senescence and death in marine microbial communities dalitros@gmail.com 
Ashraf Al-Ashhab  Ashraf Microbial and functional diversity of different water bodies ashraf.ashhab@gmail.com
Sofi Marman  Sophie Cyanobacterial toxins in fresh water sofimarman@gmail.com
Michal Grossowicz  Michal Modeling marine phytoplanktonic populations  mgrossow@campus.haifa.ac.il
Moran Paz  Moran Characterization of a hemolytic toxin from Hydra
moran_paz1@walla.com
Assaf Rotshtein   Assaf Studying mortality aspects via modeling approach in Prochlorococcus asaforly@gmail.com
Nurit Zorn  Nurit BSc project student nurit_zoran@hotmail.com
       
Alumni      
Dr. Hanit Ben-Ari   Hemolytic toxin expression from the coral Stylophora pistillata  
Eddie Fadeev   Physiological and genetic characterization of marine Alteromonas spp.  
Dr. Tamar Rahamim   The combination of aquatic ecological zooplankton ecology questions; The ecological role of cnidarian toxins  
Eliezra Glazer   Actinoporin-like genes in Hydra  

Our lab studies marine chemical ecology - the way aquatic organisms communicate through chemistry, the chemicals that mediate these interactions, and the way these interactions and chemicals affect entire ecosystems. This is a fascinating field of research that combines ecology, limnology/oceanography, biochemistry, molecular and cellular biology, physics and computational biology. In addition, studying these interactions often brings with it the discovery of novel chemical compounds which have biotechnological, pharmacological or medical uses - antibiotics, for example, are often synthesized by microorganisms in order to fight other microbes. Some of the questions we are interested in are: Do marine bacteria communicate using chemical signals? What are the roles of venom in jellyfish, sea anemones, coral and hydra? How do marine invertebrates protect themselves against pathogens? Can understanding such interactions help us model marine communities and predict how they will change in a changing world?

Here are some specific projects we are working on:

How do bacteria interact in the dilute open ocean?

Every drop of seawater contains around one million microorganisms (bacteria, small algae and other organisms such as ciliates and diatoms), which form the base of the marine food chain. Interactions between marine microbes such as symbiosis and competition determine the structure of the microbial community, and also directly affect global processes such as cloud formation, ocean acidification and greenhouse gas dynamics.

In our lab we study interactions between Prochlorococcus, a tiny single-celled microbe, which is the most abundant photosynthetic organism on Earth, and co-occurring bacteria, which make their living by consuming and respiring organic molecules. We study how growing Prochlorococcus and heterotrophic bacteria together ("co-culture") affects the physiology of each organism, as well as the regulation of the various genes in their genomes. We plan to use these data to construct mathematical models, which describe and interpret how the lives of these organisms are intertwined. Understanding and modeling the simple laboratory co-culture will give us insight and tools for interpreting the relationships between large and complex communities of these organisms in the ocean, and their impact on the global carbon cycle.

What is the chemical landscape of cnidarians?

Cnidarians such as hydra, sea anemones, corals and jellyfish are simple, mostly sessile animals that depend on bioactive chemicals for survival. Cnidarians utilize sophisticated stinging cells (nematocytes) to inject paralyzing venom into their prey, predators or competitors. In addition to the nematocyte venom, we and others have recently shown that cnidarians produce toxins in other tissues, and that these toxins are used for many biological roles: protection from pathogenic bacteria, digestion of prey and, potentially, regulation of development.

We hypothesize that, in cnidarians, bioactive compounds secreted both as localized point sources (nematocyte discharges) and across extensive body surfaces combine to create complex "chemical landscapes". These landscapes may affect the surrounding community on scales from microns to, in the case of coral reefs, hundreds of kilometers. As a first step towards describing such landscapes in detail and understanding their ecological importance, we are systematically determining the components of the nematocyte-derived venom and body-derived chemical armament of the model cnidarian Hydra magnipapillata, and are characterizing the spatial and temporal distribution (production, storage and secretion) of these components in Hydra. We are using a combination of column chromatography, high-throughput bioassays, advanced proteomics and recombinant in-vitro expression to link between specific proteins or peptides and biological activity. We plan to combine this detailed knowledge of the chemical armament of hydra with fluid dynamic models to predict the potential fluxes of bioactive materials into the environment, and their effect on the surrounding ecosystem.

research10        research09

2015

Rachamim T, Morgenstern D, Aharonovich D, Brekhman V, Lotan T, Sher D (2015). The dynamically-evolving nematocyst content of an Anthozoan, a Scyphozoan and a Hydrozoan. Mol Biol Evol (2015) 32 (3): 740-753 

Berube PM , Biller SJ, Kent AG , Berta-Thompson JW , Roggensack SE , Roache-Johnson KH , Ackerman M, Moore LR , Meisel JD , Sher D, Thompson LR , Campbell L, Martiny AC , Chisholm SW (2015) Physiology and evolution of nitrate acquisition inProchlorococcus. ISME, 9:1195–1207;doi:10.1038/ismej.2014.211

2014

Glasser E, Rahamim T, Aharonovich D, Sher D (2014) Hydra actinoporin-like toxin-1, an unusual hemolysin from the nematocyst venom of Hydra magnipapillata which belongs to an extended gene family. Toxicon, doi: 10.1016/j.toxicon.2014.04.004.

Nir O, Gruber DF, Shemesh E, Glasser E, Tchernov D (2014) Seasonal Mesophotic Coral Bleaching of Stylophora pistillata in the Northern Red Sea. PLoS ONE 9(1): e84968. doi:10.1371/journal.pone.0084968

2013

Nesher N, Shapira E, Sher D, Moran Y, Tsveyer L, Turchetti-Maia AL, Horowitz M, Hochner B, Zlotkin E (2013) AdE-1, a new inotropic Na(+) channel toxin from Aiptasia diaphana, is similar to, yet distinct from, known anemone Na(+) channel toxins. Biochem J, 451(1):81-90

2012

Rachamim T, Sher D. (2012) What Hydra can teach us about chemical ecology -how a simple, soft organism survives in a hostile aqueous environment. Int J Dev Biol, 56(6-8):605-11

Transcriptome of Anemonia viridis – please contact us directly

The big MED4 experiment

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Prof. Michael Follows' visit 

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Med cruise Nov. 2013

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At Dor fish farm

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Lab trip to Weizmann Institute, Jaffa, and Florentin

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