Cross-section of the Developing Zebrafish Heart

There are a multitude of signals that elegantly orchestrate the proper development of the heart. In this image of a 3-day-old zebrafish heart, the signal that is localized to the developing atrio-ventricular valve and smooth muscle is labeled in green using green fluorescent protein (GFP). This particular signal is important for the formation of the cardiac valves, which will allow blood to pass from the … Continue reading Cross-section of the Developing Zebrafish Heart

heart bright

Zebrafish Heart – 3 Days Old

Here is the developing zebrafish heart at 3 days post-fertilization. Unlike mammals, which have four chambers, the zebrafish heart consists of only two: a single ventricle (left) and a single atrium (right). Despite the difference in the number of chambers, the heart is the first organ to form in both mammals and zebrafish. Can you guess why? The developing embryo needs nutrients and as its … Continue reading Zebrafish Heart – 3 Days Old


Expanding the Antibiotic Arsenal: A New Drug of Last Resort

Prior to the discovery of antibiotics, bacterial infections were the leading cause of death worldwide. Now, treating infections is often a routine procedure – simply requiring a doctor’s visit and a prescribed antibiotic. However, this simple routine has become marred by the emergence of antibiotic resistance. The misuse and overuse of antibiotics is fueling the rise of resistant bacteria. In response to antibiotic exposure, bacteria have evolved … Continue reading Expanding the Antibiotic Arsenal: A New Drug of Last Resort

Spreading of Homo sapiens [Image: created by NordNordWest, release into the public domain]

When did the Americas encounter the first human?

It is widely believed that humans first arrived in the Americas around 13,000 to 15,000 years ago. Discoveries at archeological sites such as Mesa Verde in Chile and Meadowcroft, PA have long supported this view. At a dig in Southern California, possible traces of human activity from over 130,000 years ago have been discovered. Researchers at the site recovered the partial skeleton of a mastodon, an … Continue reading When did the Americas encounter the first human?

oak wood

Oak Wood Cross Section

Cross section of oak wood, showing every reason that made an oak tall and strong. The large pores are vessels that are responsible for transporting (more accurately, pumping/pushing) water from the root system to the tip of the tree. The densely packed purple dots are stained lignin in the cells walls. During early wood development, once lignin is deposited in the cell wall, these cells … Continue reading Oak Wood Cross Section