[ Pobierz całość w formacie PDF ]
Margo thought,we could do cross-comparison studies. But the CDC had demanded that all traces of
the original fibers be de-stroyed. They d even insisted on incinerating her handbag, which she d once
used to transport some of the fibers.
That was another thing. If all the remaining fibers had been destroyed, how had Greg Kawakita obtained
some of his own? How had he managed to grow them? And above all else:why?
And then there was the mystery of the flask at his lab markedACTIVATED 7-DEHYDROCHOLE.
The missing piece was obviouslysterol: she d looked it up, and had to laugh at her own stupidity. Of
course she knew at once why it sounded so familiar it was the most common form of vitamin D3. Once
she had that figured out, it didn t take long to see that the organic chem equipment in Kawakita s lab had
been a little setup hastily improvised for synthesizing vitamin D. But why?
The solution turned yellow, and she marked the level: ex-actly the same, as she knew it would be.
Frock, putting away some equipment on the far side of the lab, took no notice. She hesitated a moment,
deciding what to do next. Then she moved to the stereozoom, where she carefully teased yet another
small fiber from their rapidly dwindling sample.
Frock rumbled over as she manipulated the microscope stage. It s seven o clock,Margo, he said
gently. Forgive me, but I think you ve been working too hard. May I suggest we break for the evening?
Margosmiled. I m almost done, Dr. Frock. I d like to do one last thing, then I ll call it a day.
Ah. And what might that be?
I thought I d just freeze-fracture a specimen and get a ten-angstromSEM image.
Frock frowned. Toward what end?
Margostared at the specimen, a tiny dot on the glass stage. I m not really sure. When we first studied
this plant, we knew it carried a reovirus of some kind. A virus that coded for both human and animal
proteins. I wanted to see if this virus might be the source of the drug.
A low rumble shook Frock s capacious front, finally erupt-ing as a chuckle. Margo,I would say it is
definitely time for a break, he said. This is wild speculation.
Perhaps, Margo said. But I d prefer to call it a hunch.
Frock looked at her a moment, then sighed deeply. As you wish, he said. But I, for one, need my
rest. I ll be at Morristown Memorial tomorrow, enduring that annual battery of tests they seem to force
on you in retirement. See you Wednes-day morning, my dear.
Margosaid good-bye, watching as Frock wheeled himself out into the corridor. She was beginning to
realize that the famous scientist did not enjoy being crossed. When she d been his graduate student, timid
and compliant, he d always been utterly charming, the soul of gentility. But now that Frock was emeritus
and she was a curator in her own right, expressing her own ideas, he sometimes seemed less than
pleased with the new assertiveness.
She brushed the tiny sample into a specimen well and car-ried it to the freeze-fracture machine. Inside
the machine, it would be encased in a small plastic block, frozen to nearly absolute zero, and cleaved in
two. Then the scanning electron microscope would make an extremely high-resolution picture of the
fractured surface. Frock was right, of course: under normal circumstances, a procedure such as this
would have no bearing on their research. She d called it a hunch, but in reality it was for lack of anything
else to try.
Soon, a green light appeared on the cryogenic machine. Handling the block with an electronic cradle,
Margo moved it onto the cleaving stage. The diamond cleaver descended with a smooth motion, there
was a faint click, and the block sep-arated. Placing one of the halves in theSEM, she carefully adjusted
the mount, scanning controls, and electron beam. In a few minutes, a crisp black and white image
appeared on the adjoining screen.
Staring at it,Margo felt her blood run cold.
As expected, she could make out small hexagonal particles: the reovirus that Kawakita s extrapolation
program had orig-inally detected in the plant fibers eighteen months earlier. But here, it existed in an
unbelievably high concentration: the plantorganelles were literally packed with it. And surrounding the
particles were largevacuoles that held some kind of crystal-lized secretion that could only come from
the reovirus itself.
She breathed out slowly. The high concentrations, the crys-tallized secretions, could mean only one
thing: this plant,Liliceae mbwunensis, was only a carrier. Thevirus made the drug. And the reason they
couldn t find traces of the drug was because the drug was encapsulated inside thevacuoles.
Well then,she thought. The answer was simple. Isolate the reovirus, grow it in a medium, and see what
drug it produces.
Kawakita must have thought of this.
[ Pobierz całość w formacie PDF ]