Introduction to the Anthology

Imagine yourself standing inside a huge factory, surrounded by intricate machines of all shapes and sizes. Your initial awe at the vast array of moving parts soon turns to curiosity as you try to understand just what each machine does, how it works in harmony with the others, and what might happen if a single part were to fail. If you were to shrink this factory to miniscule proportions—smaller than even the eye could see—you could be looking at a single cell, and your awe and curiosity would be what drives discovery in the field of cell biology.

Because cells are so tiny, generally spanning between 1 and 100 microns (1 micron = 1 millionth of a meter), it is easy to forget how important they are.  Obvious reminders arise from diseases such as cancer or infections, when the functioning of the mini-factories goes awry. Yet knowledge of cellular function can be applied to everything from bioweapons to new medical technology to an understanding of why a doctor might not want to prescribe antibiotic medications for a certain disease. Progress in biotechnology and medicine becomes so much more compelling with a clear grasp of cell biology!

Cell biologists study the structure, activities, and diseases of all kinds of cells. Because cells come in many shapes and sizes, it may seem as though a nerve cell and a skin cell, a plant cell and an animal cell, a bacterium and a fungal cell could not have very much in common. In truth, cells share many similar features, so experiments conducted using one kind of cell can often be applied to questions about other kinds of cells.

At the most basic level, all cells can be placed into one of two categories:  prokaryotes or eukaryotes. Eukaryotic cells are the familiar cells that make up the human body, as well as other animals, fungi and plants. Eukaryotic cells contain a nucleus, which houses their chromosomes, and a variety of organelles. These organelles allow the cell to produce energy, to metabolize food, to destroy unneeded molecules, to excrete waste products, to move, and to synthesize proteins and other molecules. The first section of this anthology explores these cellular structures and their functions. Through the eyes of leading researchers and scientists, you will discover how cells maintain their borders with the outside, how cells "talk", and how some of the organelles function. This section will also take a close look at what defines a eukaryotic cell:  the nucleus.

For all their complexity, the development of eukaryotic cells is believed to be completely dependent on their more primitive ancestors, the prokaryotes. Prokaryotic cells, such as bacteria, are smaller and simpler than eukaryotic cells. They lack a nucleus and the complex organelles of eukaryotes. So how can it be that the mighty eukaryotic cell could not exist without prokaryotes? The second section examines the differences between the two classes of cells and peers deep into the past to discover how eukaryotic cells may have evolved through the capture of prokaryotic cells as slaves.

As if to make up for this historical injustice, prokaryotes have come to be incredibly important for both human health and human disease. For example, bacteria that live in the human gut are critical to the digestion process. These friendly bacteria help break down sugars and fats that would otherwise be lost and in turn receive a constant supply of nutrients and a safe place to live. This symbiotic relationship between friendly bacteria and human beings isn't generally a topic of great interest—until the media reports on a new outbreak of foodborne-illness. It turns out that friendly bacteria can easily become dangerously infective pathogens! You will see why in the third section. Bacteria cause other diseases and make deadly weapons as well. Who can forget anthrax, or the Black Plague? These are the other issues that the third section will explore.

A discussion of cells would not be complete without a look at one of their main enemies—the virus. Viruses measure between 20 and 250 nanometers (1 nanometer = 1 billionth of a meter) and contain their genetic information inside a geometrically-precise protein shell, called a capsid. In order to replicate itself, a virus must find a way inside a host cell and take over the cell's machinery. Viruses are usually specific for a certain host, such as humans, birds, or bacteria. Viruses are well known for causing diseases, including influenza, the common cold, herpes, AIDS, smallpox and Ebola.

However, viruses are not without their usefulness. In 1915, Félix d'Herelle, a British-Canadian microbiologist, discovered viruses that can only infect and kill bacteria, called bacteriophages. Bacteriophages are harmless to other kinds of cells. The idea of using phages to cure bacterial infections in humans has been around since that time, but the ease and efficacy of antibiotic medications supplanted research on phage treatments in the United States. However, a recent increase in the number of antibiotic-resistant, incurable bacterial infections has prompted scientists and physicians to revisit this treatment. A second area in which viruses may prove to be a useful is the treatment of genetic diseases and cancer. These treatments require the patient to be infected with viruses that can deliver corrected genes to cells whose genes are faulty, or that can kill cancer cells without harming normal cells.

The final section of the anthology will explore these topics. You will see how the tiny virus uses the cell's own molecules against it to gain entry through the plasma membrane and how it steals resources to replicate hundreds of times once inside. This section will also highlight some emerging medical treatments that use viruses. Although viral therapy is only used in clinical trials today, it has the potential to dramatically change medical treatments in the future.

The field of cell biology grows so rapidly each year that it would not be possible to capture each detail in one anthology. This collection will serve as a useful overview of cell biology, with special attention paid to practical and medical applications. Enjoy the journey of discovery!

Jillian Lokere