"microbe" - читать интересную книгу автора (Slonczewski Joan)

can bring samples back to the station. That's why we're sending me."
"Us," he corrected.
"All right, enough already," said Skyhook. "Why don't we review our data one
last time?"
"Very well." A third sentient voice boomed out of the hexagonal panel in the
dome directly overhead. It was the explorer station herself, Quantum. Quantum
was considered female, the others male; Andra could never tell why, although
sentients would laugh at any human who could not tell the difference. "Here are
some microbial cells extracted from the soil by the last probe," said Quantum.
The planet's image dissolved. In its place appeared the highly magnified shapes
of the microbes. The cells were round and somewhat flattened, rather like red
blood cells. But if one looked closer, one could see that each flattened cell
was actually pinched in straight through like a bagel.
"The toroid cell shape has never been observed on other planets," said Quantum.
"Otherwise, the cell's structure is simple. No nuclear membranes surround the
chromosomes; so, these cells are like bacteria, prokaryotes."
Skyhook said, "The chromosome might be circular, too, as in bacteria."
"Who knows?" said Pelt. "On Urulan, all the chromosomes are branched. It took us
decades to do genetics there."
"We just don't know yet," said Quantum. "All we know is, the cells contain DNA."

"The usual double helix?" asked Skyhook. The double helix is a ladder of DNA
nucleotide pairs, always adenine with thymine or guanine with cytosine, for the
four different "letters" of the DNA code. When a cell divides to make two cells,
the entire helix unzips, then fills in a complementary strand for each daughter
cell.
"The nanoservos failed before they could tell for sure. But it does have all
four nucleotides."
Andra watched the magnified microbes as their images grew, their ring shapes
filling out like bagel dough rising. "I'll bet their chromosomes run right
around the hole."
At her shoulder Skyhook's eyespeaker laughed. "That would be a neat trick."
Quantum added, "We identified fifteen amino acids in its proteins, including the
usual six." All living things have evolved to use six amino acids in common, the
ones that form during the birth of planets. "But three of the others are
toxic--"
"Look," exclaimed Andra. "The cell is starting to divide." One of the bulging
toroids had begun to pucker in, all along its circumference. The puckered line
deepened into a furrow all the way around the cell. Along the inside of the
"hole," a second furrow deepened, eventually to meet the furrow from the outer
rim.
"So that's how the cell divides," said Skyhook. "Not by pinching in across the
hole; instead it slices through."
"The better to toast it."
At that Pelt's pseudopod made a rude gesture. "Pinching the hole in wouldn't
make sense, if your chromosome encircles the hole; you'd pinch off half of it."
Andra squinted and leaned forward on her elbows. "I say--that cell has three
division furrows."
"The daughter cells are dividing again already?" Skyhook suggested.
"No, it's a third furrow in the same generation. All three furrows are meeting