5 Potentially Immortal Animals

Hydra viridissima; Credit: Frank Fox

With Google now venturing into the oh so Vanilla Sky business of life extension via Calico, it seemed like a good time to explore the age old dream of immortality. It seems that while we humans have struggled in vain to attain the seemingly impossible goal of biological immortality, other creatures make it look quite easy. Of course when scientists speak of  "biological immortality",  they mean organisms that do not experience the cellular senescence associated with aging, and so their mortality rate doesn't increase after maturity. Most of the organisms on this list could still be easily dispatched by any number of means, including the ever popular pot of boiling water. It's also prudent to mention that while they might not show the classic signs of aging, scientists are not quick to call anything immortal without a lot of research, hence the "potentially" in the title of this post.

Functions of the Rough and Smooth Endoplasmic Reticulum

Smooth and rough endoplasic reticulum; Credit: Wikimedia

The endoplasmic reticulum is a network of flattened sacs and tubules that perform various functions in our cells. This network is divided into two regions that differ in both, function and structure. These regions are called, the rough endoplasmic reticulum and the smooth endoplasmic reticulum.

Protist Pathogens in Humans

Plasmodium gallinaceum (Malaria) in mosquito gut; Credit: Wikimedia

Protists are a biologically diverse group of eukaryotic organisms. They are generally considered to be single celled and lack any of the specialized tissues associated with more complex groups of organisms, but these are their only defining features – without looking genetically. Their metabolism can be phototroph or organotroph, and the way they reproduce varies wildly depending on the specific species.

They might be difficult to define, but their role as pathogens is more certain. Some species will act as pathogens to plants, others to animals, but perhaps the most well-known are those in the Plasmodium genus, which can cause malaria in humans.

The Economic Importance of the Common Protist

Paramecium bursaria, Credit: Protist Information Server

Protists are a varied set of organisms that have little in common with each other. This variety makes classifying them extremely difficult without genetic sequencing, but also means they have a range of different roles, and potential benefits. When a group of organisms have a distinct benefit to humans there is normally a distinct economic implication – an example of this is the value of livestock to farmers. The value associated to protists may not be as common, or well-known, but they do exist.

Fermantation and Anaerobic Respiration

Ethanol Fermentation; Credit: Davidcarmack

Oxygen plays a vital role in aerobic respiration, but isn’t always readily available in every environment, or situation – conditions that lack the presence of oxygen can be described as ‘anaerobic’. In these conditions only a few types of organism can thrive:

Facultative anaerobes – are organisms that can respire aerobically if oxygen is present, but also have the ability to switch to ‘fermentation’ to meet their energy requirements.
Obligate anaerobes – can only survive in the absence of oxygen. The organisms die if oxygen is introduced into their environment.

To fully explain ‘anaerobic respiration’ and ‘fermentation’ it’s first important to understand what oxygen actually does in aerobic respiration.

Golden Eagle Catches Deer On Camera

Golden Eagle capturing young sika deer; Credit: Linda Kerley

Linda Kerley of the Zoological Society of London, runs a camera trap project in Russia, where they hope to snap pictures of endangered tigers. What researchers found on a recent trip however was far more rare. Dr. Kerley was initially puzzled when she found deer remains near the trap. The surrounding snow showed no tracks from a large predator like a tiger or bear.

Toxoplasma Makes Mice Lose Fear of Cats

A mouse infected with the Toxoplasma parasite loses its fear of cats; Credit: Wendy Ingram

The Toxoplasma protozoan parasite is not only a hazard for pregnant women, few are aware of how it also affects the behavior of mice. Infected mice actually seem to lose their fear of cats, which is not only beneficial to felines, whom receive an easy meal, but allows the parasite to complete its life cycle within the cat's gut.

The mind altering effects appear to be permanent and persist long after the mouse has recovered from the initial onset of toxoplasmosis. This appears to be true even when the parasites cysts are not present in the brain, indicating that a permanent change has been made. Wendy Ingram at the University of California, Berkeley speculates that the section of the brain responsible for smell has been damaged, meaning mice can no longer sense cat urine.

The research is particularly interesting because it's believed that up to one-third of the world's population has been exposed to the Toxoplasma parasite. A healthy immune system will keep the dormant cysts under control for most, but immunocompromised individuals may have health concerns. There is even reason to believe that chronic infection is linked to schizophrenia and suicidal behavior.

Sources:
PLOS ONE
Eisenlab.org