Living Wonders at a Glance
Here is an assortment of recently-reported biological marvels at the cellular level. Researchers into creation and evolution explanations may wish to delve into these more deeply.
- Clock Conductor: The brain is a “time machine,” reports EurekAlert on research at Duke University about the human biological clock. Each structure in the brain has a resonant frequency of oscillations, like the ticking of a clock. How do they get coordinated? Think of the tune-up at the beginning of a concert, says Catalin Buhusi of Duke: “It’s like a conductor who listens to the orchestra, which is composed of individual musicians. Then, with the beat of his baton, the conductor synchronizes the orchestra so that listeners hear a coordinated sound.”
- Molecular Scissors: MicroRNAs (miRNA) have been implicated in recent years with the regulation of genes (09/08/2005), including silencing genes that need to be slowed down or stopped. EurekAlert reported on work by Wistar Institute that detected a “molecular scissors”action involving three independent parts: “The two enzymes in the complex are like two scissors working together in a concerted fashion, connected and coordinated by the third member of the complex,” said Ramin Shiekhattar. The activity apparently occurs without any expenditure of ATP energy.
- Nerve Code: Scientists at Howard Hughes Medical Institute were surprised at an unexpected discovery: neuron development follows a code – “an organized relationship between Hox proteins, their chromosomal organization, and the differentiation and connectivity of motor neuron pools.” The discovery of a combinatorial code, which governs three levels of motor neuron organization, “shows how the nervous system can generate the huge diversity of neurons necessary for a complex task like locomotion.” Song and Pfaff of the Salk Institute reported on this surprising find in Cell, titling their article, “Hox Genes: The Instructors Working at Motor Pools.”
- Sprinting Motor: Like a sprinter crouching at the block before sprinting, kinesin stores up energy before its 7.8 nanometer leaps, reported Fisher and Kim in PNAS last month. And like a strong sprinter, it’s not a pushover: “sideways lurching is not supported.”
- Give Me Iron, or Give Me Death: Taylor et al., writing in PNAS, studied the structure of a yeast enzyme named Fet3p essential to oxidizing both iron and copper. The regulation of these metal ions is essential; Taylor et al. said, “Loss of the Fe(II) oxidation catalyzed by these proteins results in a spectrum of pathological states, including death.”
- Gecko Rain Dance: Geckos have a billion spatula-shaped structures at the ends of the hairs on their feet that allow them to “adhere to nearly all surface topographies.” Huber et al. in PNAS explored the capillary action on a single spatula and found that “humidity contributes significantly to gecko adhesion on a nanoscopic level.” They were interested in learning about gecko feet “for the development of artificial biomimetic attachment systems.”
- Packaging into the Cell: Some cargoes get wrapped in membrane and are delivered right through the cell exterior; this is called clathrin-mediated endocytosis. Kaksonen, Toret and Drubin at UC Berkeley found that “four protein modules that cooperate to drive coat formation, membrane invagination, actin-meshwork assembly, and vesicle scission during clathrin/actin-mediated endocytosis.” The clathrin itself (an interesting three-pronged protein that forms geodesic structures around the vesicle) “facilitates the initiation of endocytic-site assembly but is not needed for membrane invagination or vesicle formation.” The work was reported in Cell; see also EurekAlert summary.
- Not Just a Recycle Bin: The proteasome is getting more respect. This “large multiprotein complex” is critical to the degradation of proteins tagged for recycling. Baker and Grant reported in Cell that the proteasome was found involved in gene activation, adding to a “growing body of evidence indicating that the proteasome has nonproteolytic functions.”
- Sharper Image: Peter Moore in Science was glad about the “ribosomal coup” performed by Schuwirth et al. in the same issue, who imaged the bacterial ribosome at 3.5 angstrom resolution. This molecular machine, the protein assembly factory, has moving parts. Moore said, “The two subunits of the ribosome not only communicate during protein synthesis, they also engage in coordinated, relative motions.”
- Bacterial Centipedes: Did you know that bacteria can walk? They project little feet called pili that adhere to surfaces; as the bacteria retract them, they pull the bacteria along in a crawling motion. Researchers at UC Berkeley reporting in Science found a signaling molecule that they watched traveling from one end of the bacterium to the other when the organism needed to change directions. They figured that this enzyme, FrzS, constituted a chemosensory system that hops onto the intracellular highway and orchestrates the formation of the pili.
- Mr. Peabody Gains Respect: Little specks called P-bodies near the nucleus never had so much limelight. Jean Marx, writing in Science, told how scientists used to think they were just trash cans for used messenger RNAs (mRNA), a dead-end job. Now, it appears that these “tiny speckles at the heart of the cell’s machinery” are active, critical players in the regulation of protein synthesis. They act like routers, holding onto mRNA transcripts while deciding which get used or recycled. Are they important? When they go awry, cancer and autoimmune diseases can result.
- Bees Under the Floodlights: Humans can distinguish red, yellow and other colors under different lighting conditions, an ability called color constancy. Bees have this talent, too. To prove that weird lighting in a natural setting doesn’t throw them off, two London scientists put bumblebees in a specially-lit chamber. All the flowers had black backgrounds, and four colored lights could alter the ambience. They found that “bees can generate color-constant behavior by encoding empirically significant contrast relationships between statistically dependent, but visually distinct, stimulus elements of scenes” – spoken like a scientist, but the bees get the applause.
These 12 brief glimpses at recent science literature hint at the stream of discoveries being made that uncover more and more complexity and coordinated design. Most of these papers don’t even mention evolution; none of them try to account for the origin of the complex structures they studied. On the contrary, if the reports had been written by members of the intelligent design movement, no one would be able to tell the difference. Both groups would express astonishment – but for different reasons.