Today’s New Reason To Believe

Posted by Fazale ‘Fuz’ Rana, Ph.D.

I always know when our water purification system isn’t working right. All it takes is a gulp of water from the kitchen tap. The intense salty taste followed by spewed water in the sink is a telltale sign that the system isn’t properly washing the column with the liquid from the brine tank.

Salty water is not good to drink—and it’s distasteful for life. Living organisms can tolerate only so much salt. In fact, because of its antimicrobial effects salt is used to cure and preserve meat. High salt in the milieu kills by drawing water out of the microbial cells through the process of osmosis.

New research indicates that salt may have acted as a preservative of sorts on Mars, preventing life from taking hold early in its history.

Astrobiologists focus a lot of attention on detecting life (and/or the remains of ancient life) on Mars. Many scientists argue that if life exists on Mars, particularly if it’s distinct from Earth life, then it validates the evolutionary paradigm. Unique Martian life-forms would seemingly imply that life had arisen twice, once on Earth and once on Mars.

Evidence for ancient life on Mars carries implications for the origin of life on Earth. As Hugh Ross and I discuss in Origins of Life life’s first appearance on Earth is enigmatic within the evolutionary paradigm. Instead of life emerging gradually over a vast period of time (several hundred million years), it appears suddenly as soon as the Earth can sustain it. And the first life on Earth is remarkably complex, metabolically speaking. This makes little sense from an evolutionary perspective, prompting some origin-of-life researchers to speculate that perhaps life originated on Mars very early in its history and was transported to Earth on Martian meteors. Accordingly, life’s first appearance on Earth about 3.8 billion years ago was not an origination event, but the arrival of life from Mars. If it was transported to Earth, it would seem as if it appeared suddenly in the geological record.

Support for this idea comes from the discovery that ancient Mars was a warm, wet planet. But just because Mars once harbored liquid water on its surface doesn’t necessarily mean that life existed on the Red Planet. Liquid water is only one requirement for life. The temperature, pH, and salinity of the water impact habitability.

Recently a team of astrobiologists from Harvard University determined that the salinity of the water on early Mars, as far back as 4 billion years ago, would have rendered the planet uninhabitable. The water on early Mars appears to have been much saltier than Earth’s sea water. In fact, the water on Mars must have been saltier than bodies of water that harbor halophiles, salt-loving microbes that thrive in high saline environments.

Previous work has demonstrated that high salt levels interfere with the assembly of RNA molecules on mineral surfaces, a central idea in the RNA World hypothesis for the origin of life. Large quantities of salt also frustrate the assembly of fatty acids into primitive cell membranes. These are two key stages in most origin-of-life pathways.

The idea that life existed or originated on Mars early in its history has just been spewed into the sink. The water is way too salty.

Posted by Dr. Fazale Rana

Nanobacteria Inorganic Material, Not Life

Common wisdom would say that someone who is less than six feet tall would never make it as a professional basketball player. Size matters in the NBA.

Size also matters to biochemists. Conventional wisdom places the lower bound on life at about 1 micron (give or take a few hundred nanometers). In 1999, the National Academy of Sciences sponsored a workshop on the minimal size requirements for life and concluded that life can’t exist if it’s less than 200 to 300 nanometers in size. This lower limit stems from the fact that the simplest conceivable living organism requires about 250 to 400 different proteins plus the genes and ribosomes needed to make them.

Some scientists, however, have challenged the prevailing view on these minimum size limits. They claim that they have evidence for bacteria well under 100 nanometers in size, so-called nanobacteria. Maybe size isn’t as important as biochemists think. There have been basketball players under six feet tall, like Calvin Murphy who had a successful career in the NBA even though he is only 5’ 9”. In fact, Murphy was elected to the Basketball Hall of Fame.

Even though nanobacteria are diminutive, they may make a big impact in a number of scientific arenas. Some biomedical researchers have implicated these putative nano-microbes in gallbladder and kidney stone formation, rheumatoid arthritis, some forms of cancer, and even Alzheimer’s disease. Some microbiologists claim to have detected nanobacteria in geological samples and have suggested that they may play a key role in some geochemical cycles. NASA scientists claimed that nanobacteria left behind fossil remains in the Martian meteorites ALH84001, opening up the possibility that life originated on Mars.

If nanobacteria exist then what are they? There is much debate about the identity of nanobacteria. Some claim that they are organisms that push the bounds of what we currently think is possible for life. Proponents of this view point out that before the discovery of extremophiles, few would have thought that life could exist, let alone thrive, under the extreme conditions of high temperatures and pressures, high concentrations of salt, or under highly acidic or alkaline conditions. Could it be that nanobacteria challenge our current understanding about the size requirements for life?

Some think that nanobacteria represent a transitional form of sorts. They speculate that these organisms are some type of primitive self-replicating system that connects contemporary life to more primitive life-forms.

Others think that nanobacteria represent a completely novel form of life—life as we don’t know it.

New work published in the Proceedings of the National Academy of Sciences sheds light on the identity of nanobacteria and has broad-reaching implications for such considerations as pathogenesis (origin of disease), the definition of life, the origin of life, and the possibility of life on Mars.

Evidence for Nanobacteria

Support for the existence of nanobacteria comes primarily from biomedical work and includes: 1) the ability to cultivate slow-growing cultures in growth media after inoculation from human serum; 2) the ability to raise antibodies to nanobacterial antigens; 3) bacteria-like appearance of nanobacteria when visualized with electron microscopy (such as uniform size, vesicular shapes that appear to be delineated by a membrane, structures that appear to capture cell division, and aggregation into colonies); and 4) the recovery of 16srRNA gene sequences associated with nanobacteria. In fact, a biotech company Nanobac Pharmaceuticals has recently been launched to commercialize diagnostic and treatment protocols for pathogenic nanobacteria.

An Early Challenge to Nanobacteria

In the midst of all the excitement about nanobacteria, some researchers have expressed skepticism about their bio-authenticity. For example a study published in 2000 argued that nanobacteria are actually inorganic deposits of hydroxyapatite. (See here for further discussion.) The results of this work, however, have been largely ignored.

A More Recent Challenge to Nanobacteria

A new study, just published, takes up where the older work left off. This new research affirms that nanobacteia are inorganic in nature, not biological entities. The researchers demonstrated, however, that instead of being hydroxyapatite, nanobacteria are calcium carbonate precipitates. These workers were able to grow nanobacteria-like particles from calcium carbonate that had uniform size and shapes, and appeared to be bound by a membrane with some appearing to undergo a cell-division process. These precipitates also aggregated into colony-like structures. The formation of these precipitates did require the presence of human serum. Presumably the proteins in the human serum controlled the morphology of the calcium carbonate deposits. It turns out that the response of the nanobacteria-like precipitates to antibodies seems to originate from human serum protein contaminants associated with the calcium carbonate.

Other results which favor the inorganic interpretation of nanobacteria include: 1) the failure to detect any DNA associated with the nanobacteria-like material; 2) the ability to generate growth after filtering the serum-inoculated growth medium through 0.1 micron pores; and 3) the ability to generate growth after irradiation with gamma-rays.

Implications

The implications of this latest work are profound. If nanobacteria are inorganic then:

• Nanobacteria do not cause disease.
• It appears that life can’t exist below about 250 to 300 nanometers in size. This means that life requires a significant level of complexity to even exist (250 to 400 different proteins plus the genes and ribosomes needed to make them).
• Nanobacteria are not a primitive self-replicating entity.
• The evidence for ancient life on Mars is negated.

The long and the short of it (no pun intended; well, actually, it was intended), nanobacteria are not life’s version of Calvin Murphy.

David H. Rogstad, Ph.D.

A couple of months ago I discussed an upgrade to the Arecibo Radio Telescope that would make it more effective for searching for intelligent life in outer space (SETI). That article included references to cases made, from a secular and a theistic point of view, for the improbability of finding intelligent life “out there.” These approaches call attention to the vast number of conditions that must be met for life to survive in any environment and the difficulty in meeting those conditions all at the same time. The authors’ conclusion is that Earth, which has supported advanced life over an extended period of time, may be unique in the observable universe. This idea is often referred to as the Rare Earth Hypothesis.

Andrew Watson of the University of East Anglia in the UK reports, in the February 1, 2008 issue of Astrobiology, on a mathematical study he performed that lends further support for the idea that intelligent life in the universe is rare. While he approaches the problem from a naturalistic perspective, his arguments have broad application. He begins by noting that advanced life has appeared late in Earth’s history, approximately 4 billion years after primitive life first appeared. And due to the increase of the Sun’s luminosity, Earth can support this life another billion years at most—a short time compared with the time since its origin.

On the ground of some general principles entailed in the stochastic (statistical, involving random variables) model used for his study, Watson then argues that the timing of the appearance of intelligent life will be governed by the necessity of life passing at least four very difficult evolutionary steps. The four stages he chose correspond to major steps apparent in the fossil record, including the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life-forms, and intelligent life with an established language.

Watson argues that each step is independent of the other and can only take place after the previous steps in the sequence have occurred. He estimates the probability of each step occurring as 10 percent or less, so the chance of intelligent life emerging in an Earth-like environment is low, less than 0.01 percent over the four billion years of life’s history. On this ground he concludes that even with Earth-like conditions, there is still a very low probability that intelligent life will develop.

If we multiply this percentage by the extremely small probability for finding an Earth-like environment, then the likelihood for finding intelligent life anywhere else in the observable universe is virtually zero. This study argues against a random chance scenario, but fits well with the RTB creation model, where we expect that the appearance of life requires the direct hand of a creator who has placed it in this universe for a purpose.