Shufflebrain

WE RETURN TO THE IMPERFECT but comfortable realm of experience. In chapters 5 and 6, we sought out predictions in hologramic theory. Now we shift emphasis to explanations, to the use of hologramic theory for making rational sense of certain equivocal and seemingly unbelievable observations. And we start with the behavior of bacteria.

Bacilli, rod-shaped bacteria, propel themselves through fluid with whip-like appendages called flagella. flagellar motion depends on a contractile protein hooked to the base of each microbial appendage. An individual flagellum rotates, in the process executing wave motion. Locomotion of a bacillus, therefore, is an algebraic function of the phase and amplitude spectra collectively generated by its flagella. We might even regard the overt behavior of a bacillus as a direct consequence of periodic activity--the phase and amplitude spectra--reflecting the rhythm of its contractile proteins. Thus if a hologramic mind exists in the bacillus, it shows up literally and figuratively right at the surface of the cell.

But is there really a mind in a creature so primitive? We can describe a stretching and recoiling spring with tensor transformation. But our intuitions would balk, and rightfully, if we tried to endow the back porch door with hologramic mind. Thus before we apply hologramic theory to the bacillus, we need evidence only experiments and observations can supply.

Single cells of many sorts can be attracted or repelled by various chemicals. The reaction is called chemotaxis. In the 1880s, when bacteria was still a very young science, a German botanist named Wilhelm Pfeffer made an incredible observation in the common intestinal bacillus, Escherichia coli (E. coli)-- more recently of food-poisoning fame. Other scientists had previously found that meat extract entices E. coli whereas alcohol repels them: the bacteria would swim up into a capillary tube containing chicken soup or hamburger juice but would avoid one with ethanol. What would happen, Pfeffer wondered if he present his E. coli with a mixture of attractants and repellants? He found if concentrated enough, meat juice would attract E. coli even though the concentration of ethanol was enough, by itself, to have driven the bacteria away.

Did Pfeffer's observations mean that bacteria make decisions? Naturally, the critics laughed. But in comparatively recent times biochemists have begun to rethink Pfeffer's question. And in rigorously quantified experiments with chemically pure stimulants, two University of Wisconsin investigators, J. Adler and W-W Tso came the conclusion, "apparently, bacteria have a 'data processing' system." Courageous words, even within the quotations marks. For in a living organism, 'data processing' translates into what we ordinarily call thinking.

Adler and Tso established to important points. First, the relative--not absolute--concentrations of attractant versus repellent determines whether E. coli will move toward or away from a mixture. Second, the organisms do not respond to the mere presence of stimulants but instead follow, or flee, a concentration gradient. And it was the consideration of concentration gradient that led biochemist D. E. Koshland to establish memory in bacteria.

Koshland became intrigued by the fact that a creature only 2 micrometers long (.000039 inches) could follow a concentration gradient at all. The cell would have to analyze changes on the order of about one part in ten thousand--the rough equivalent of distinguishing a teaspoon of Beaujolais in a bathtub of gin, a "formidable analytical problem," Koshland wrote.

Did the cell analyze concentration variations along its length? To Koshland's quantitative instincts, 2 micrometers seemed far too short a length for that. Suppose, instead, the bacterium analyzes over time, instead of space (length)? What if the cell could remember the past concentration long enough to compare it with the present concentration? Koshland and company knew just the experiment for testing between the two alternative explanations.

When a bacillus is not responding to a chemical stimulus, it tumbles randomly through the medium. (Its flagella crank randomly.) In the presence of a stimulus, though, the bacterium checks the tumbling action and swims in an orderly fashion. What would happen, Koshland wondered, if he tricked them? What if he placed the organism in chemical stimulus (no gradient though) and then quickly diluted the medium? If the bacteria indeed analyzes head-to-tail, they should go right on tumbling because there'd be no gradient, just a diluted broth. But if bacteria remember a past concentration, diluting the medium should fool them into thinking they were in a gradient. Then they'd stop tumbling.

"The latter was precisely what occurred," Koshland wrote.[1] The bacterial relied on memory of the past concentration to program their behavior in the present.