Ramses Long

Participant: PROMISE AGEP Research Symposium


Ramses Long

Department: Biology

Institution: University of Maryland, Baltimore County (UMBC)



Determining Wavelength Absorptions of Mantis Shrimp Opsins

The stomatopod crustacean, Squilla Empusa, has six types of opsins despite possessing only one main class of photoreceptor. Previous immunohistochemical staining experiments from this lab has shown that Opsins 5 and 6 are the most abundant and are present throughout the retina. We also know that the peak absorbance of all photoreceptors is 517 nm. The first goal of this project is to characterize the wavelengths of absorption for Opsins 5 and 6 to determine how they contribute to that peak value of 517 nm. We hypothesize that both opsins are spectrally similar, but may have different structural properties based on different amino acid substitutions in intracellular loops 2 and 3 (ICL2 and ICL3), both being key sites for facilitating G-protein binding. The varying structures may lead to functional differences between the opsins. We plan on determining an absorption spectrum of Opsins 5 and 6 using a Baculovirus expression system. We inserted the Opsin 6 into a Baculovirus and infected the larvae of cabbage looper (trichoplusia ni) with it. After isolating the protein from the larvae, we will determine their spectral properties through absorption spectroscopy.



I am pursuing a Master’s Degree in Applied Molecular Biology at UMBC to help me clarify my research goals and career aspirations. I was introduced to the field of biological research in the Summer of 2015 when I began working in Dr. Ostrand-Rosenberg’s tumor immunology lab as an undergraduate researcher. The experience was eye-opening. I delved into the emerging field of tumor immunology which is essentially the use of medications to strengthen people’s immune systems to fight cancer as opposed to more traditional cancer treatments that involve radiation, surgery, or chemotherapy. The promise of using my problem-solving skills to contribute a small part of knowledge to the world of biological research brought me to this postbaccalaureate program after I graduated in May of 2017. When I joined this program, I started working under Dr. Thomas Cronin and Dr. Phylis Robinson to observe the properties of Squilla Empusa Opsins.



Stomatopod crustaceans (mantis shrimps) have the most complex system of vision because of the broad range of wavelengths of light they can see, and the amount of photoreceptors they have. Stomatopod crustaceans can have up to 16 different photoreceptors, compared to two in humans (rods and cones). The variety of photoreceptors makes this a great model organism for studying vision.

Photoreceptors are the cells in the eyes that allow them to recognize light. The structures in photoreceptors that allow them to recognize light are called opsins. Opsins are G Protein Coupled Receptors (GPCRs) that initiate the signal transduction pathway that allows for the sensation of light.

In this project, we studied the opsins of Squilla Empusa, a type of stomatopod crustacean that has only one type of photoreceptor. All its photoreceptors absorb maximally at 517 nm. This corresponds to a greenish color on the electromagnetic spectrum. This would lead one to believe that there is only one type of opsin for the one type of photoreceptor. However, previous research has shown squilla empusa has six different opsins, with Opsins 5 and 6 (SE5 and SE6) being expressed the most throughout all photoreceptors.3

The goal of this project is to characterize the wavelengths that Opsins 5 and 6 absorb so we can have a better understanding of how opsins and photoreceptors in squilla empusa work together to create that 517 nm peak absorbance.



  1. “Frontline Science: Myeloid-derived suppressor cells (MDSCs) facilitate maternal-fetal tolerance in mice.” This is published in the Journal of Leucocyte Biology.
  2. “Frontline Science: High fat diet and leptin promote tumor progression by inducing myeloid-derived suppressor cells” This is published in the Journal of Leucocyte Biology.

Poster Presentations:

The Impact of Myeloid-Derived Suppressor Cells on Obesity and the Association with Cancer

·       Summer Undergraduate Research Fest 2015, Catonsville, Maryland.

Reducing 30-Day Readmissions at Tufts Medical Center

·       Tufts Sacker School Building Diversity in Biomedical Sciences (BDBS) Program Poster Presentation 2016, Boston, Massachusetts. Poster Presentation.


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