Photographing the Invisible

Fall 2016 | Efrain Rivera-Serrano

The cell is a remarkable biological structure that serves as the basis of life as we know it. In eukaryotes, which are mostly (but not exclusively) multicellular organisms such as animals, plants and fungi, the intracellular compartments of the cell are highly organized – akin to a factory and its multiple departments and offices. Importantly, not all ‘cells’ are the same; and they can vary drastically in their form, arrangement, morphology, movement, mitotic (cell division) rate, and even the abundance of specific organelles depending on the tissue they reside in and their specific functions. The development of fluorescence microscopy in the 20th century opened an inexhaustible number of doors for how biologists study the fundamentals of cell biology, and provided an extremely useful tool for the visualization of what is happening inside the cell under certain conditions.

In my research, I use fluorescence microscopy to address an overall biological question, how do different cardiac (heart) cells respond to a viral infection? A variety of viruses can infect the heart to cause a disease collectively known as myocarditis. In the disease, the virus attacks the heart muscle, leading to inflammation of the heart tissue and disruption of the electrical impulses that set the rhythm of the heartbeat. As well as weakening the heart, this can also cause heartbeat irregularities and in worst cases, heart failure.

Visualizing whether a virus is inside a cell has been made possible by fluorescence microscopy. Not only does this technique allow me to see the internal structures of each cell type, fluorescence microscopy also allows me to conceptualize the battleground that takes place inside a cell after a virus has entered. One of the main reasons viruses are so efficient at infecting and spreading throughout the body is because they are able to take control of the infected cell’s own machinery and replicate themselves to make hundreds and thousands of virus copies. To study this, I am also using fluorescence microscopy to see exactly what happens when this invasion and takeover occurs. A greater understanding these processes will ultimately lead to the design of medication that can help protect and treat myocarditis.

Throughout the evolution of biological research, microscopy continues to function as a fundamental tool for scientists of many different fields, and the constant advancements in microscopy sciences has allowed the progress of research in ways that were unimaginable half a century ago.

Below are some examples of my photography work:

The building blocks of a heart

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Photo credit: Efrain Rivera-Serrano

The mammalian heart is chiefly composed of two specific cell types, both of which are essential for proper organ function. Cardiac myocytes, shown here in green, constitute the muscle portion of the heart and execute the organ’s ‘beating’ functions, which are necessary for the distribution of oxygenated blood throughout the body. These cells are largely non-replenishable, meaning that right now your heart will contain pretty much the same cardiac myocytes that you were born with. In contrast, cardiac fibroblasts, shown here in red, are readily replenishable. Unlike myocytes, cardiac fibroblasts ensure the heart functions properly and physiological homeostasis is maintained by secreting a wide variety of soluble signals and proteins.

From a mouse heart

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Photo credit: Efrain Rivera-Serrano

Two individual fibroblasts isolated from a mouse heart. The cell cytoskeleton is responsible for a myriad of cellular processes including maintaining cellular structure, facilitating cell movement, transporting molecules across the surrounding cell membrane, controlling cell division, and many other key aspects. In these two cells, both the microtubule network (green) and intermediate filaments (yellow/red) can be observed; in some cases originating from places near the nucleus (blue).

Viral infection

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Photo credit: Efrain Rivera-Serrano

A culture of mammalian cells, some of which are expressing a viral protein (green). Eukaryotic cells, which are complex and have distinct internal compartments, possess discrete structures (red) inside the nucleus (blue), the control center of the cell. In this image, it is possible to see that the presence of a virus (green cells) has caused the structures in the nucleus (red) to become more filament-like and stringy.

The spread of a virus

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Photo credit: Efrain Rivera-Serrano

The heart is responsible for receiving and distributing blood throughout the animal body. By doing so the heart provides a vital supply of oxygen and nutrients to tissues and organs. Exposed to vast volumes of blood, cardiac cells are extremely vulnerable to harmful blood-borne pathogens, and any microscopic threat, such as a virus, that gains access to the heart therefore has the potential to cause damage to the heart’s tissue. In this image, a culture of cardiac fibroblasts have been infected with a virus to study how the infection took place. The cytoskeletal framework of the cell (magenta), the cell’s energy- generating mitochondria (red), and the central control system of the cell, the nuclei (blue), of each cardiac fibroblast can be seen. The cell in the center has been infected with a virus, and clearly visible are the inclusion bodies of the virus (green), which are the sites of viral replication.


Efrain Rivera-Serrano is a PhD student in the Department of Molecular Biomedical Sciences at NC State University, funded by the National Institutes of Health. He received his undergraduate degree from the Pontifical Catholic University of Puerto Rico and his Master’s degree from NC State University. Rivera-Serrano’s published work can be found in PLOS One and the Journal of Virology. His current research focuses on exploring the molecular mechanisms of viral infection of heart cells to identify new targets for future medications to combat heart infection.