Tag: Immune System

Medicines from the sea

Only within the last several decades have scientists begun to mine the rich marine medicines and nutrients available in the seas. The bodies of some ocean animals, in fact, could hold the keys to new treatments for human diseases such as cancer, Alzheimer’s disease, and AIDS. These creatures have survived changing environments for millions of years.

Ocean animals tend to be simpler in structure than humans. An advantage for medical researchers is that ocean animals’ cell structure and growth are easier to observe and understand than typical laboratory animals.

For instance, consider the recent research on squids and human brains. A single squid’s nerve fibers are large enough to be easily studied. Neurobiologists have been using them for awhile to investigate two human brain abnormalities: Alzheimer and Lou Gehrigs diseases. Or, let’s look at the work on cyanobacteria and AIDS. Single-cell cyanobacteria are neither plants nor animals. They evolved 3.5 billion years ago, the first photosynthesizing organisms on earth. Somehow, they managed to survive our planets poisonous environment and used the sun’s energy to produce oxygen, creating our present life-sustaining atmosphere. Researchers are currently testing cyanobacteria to see it they contain a substance that could help defeat AIDS once and tor all.

The horseshoe crab is also useful in biomedical research. Its optic nerves helped researchers understand human vision. Now scientists are intensively studying its large, bacteria-killing amoebocyte cells.

Among the ocean’s many coral reefs-often compared to rain forests on land-are life forms such as sea squirts and sponges, which defend themselves with powerful toxins. Researchers have discovered a variety of uses, therapeutic and experimental, for these exotic chemicals.

Our understanding of how human cells fight disease came from ocean observations. In 1883, Russian-born scientist Elie Metchnikoff noticed that free-floating cells in a starfish would swarm toward a foreign object in the starfish’s body and clump around it. His observation, and a quarter of a century of hard research, led to our present knowledge of the immune system’s cellular functions when infection is present.

Sharks – The adaptable old-timer

“Biologically, the species is the accumulation of the experiments of all its successful individuals since the beginning”

H.G. Wells (1866-1946), British author. A Modern Utopia Ch 3, Sct 4 (1905; repr in The Works of H. G. Wells, Vol 9, 1925).

Sharks are cartilaginous fish (i.e., having a skeleton wholly or largely composed of cartilage). They vary greatly in size, behavior, and in the way they reproduce. They are found at all depths in all the oceans of the world except the Antarctic. However, they are most abundant in tropical and subtropical waters. A few species of shark inhabit freshwater lakes and rivers, and some migrate regularly from salt to freshwater.

Sharks are remarkably successful animals, with few parasites or diseases and almost no enemies except other sharks, As predators and scavengers, sharks play a major role in the ecosystems of the world’s oceans.

Paleontologists believe that sharks evolved from some primitive, heavily armored, sluggish placoderm that became extinct about 350 million years ago, at the end of the Devonian era. This is approximately when the first shark-like creatures appeared. Sharks almost identical to those living today evolved about 160 million years ago, during the Jurassic period (same time period as represented in the movie, Jurassic Park). This species has survived unchanged for 160 million years in contrast, we poor Homo sapiens have been around for less than million years.

Well-attuned to most of the water of the world, sharks appear to dominate the depths. Swimmers, water skiers, snorkels, scuba divers, and spear fishermen are invading their habitats in every-increasing numbers. Sharks have responded with predictable reflex reactions: They have attacked. The resulting notoriety has given sharks a bad reputation. The mass media have embellished the image, and now most people react with alarm to the word “shark.” However, the facts don’t support this dread of sharks. Of the 100 or so unprovoked attacks that occur worldwide every year, fewer than 35 are fatal.