Vitals. Greg Bear

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      ‘Mitochondria used to live free, a few billion years ago. Then they invaded primitive host cells, became parasites. Eventually, the hosts – our one-celled ancestors – found that the invaders had a talent. They were eight times better at converting sugar molecules into ATP. We formed a symbiotic partnership. The mitochondria became essential. Now, we can’t live without them.’

      ‘And mitochondria tell us when to grow old and die?’

      ‘They have a big say.’

      He pinched and tugged his earlobe. ‘Explain.’

      ‘The mitochondria turn state’s evidence. Kind of a fifth column. They monitor our stress levels, track our physical and mental health, and pass that information on to tiny bacteria hiding in our tissues.’

      ‘We have germs in our tissues?’ Montoya asked, frowning. ‘Doesn’t the immune system clean them out?’

      ‘Some bacteria burrow deep and hide out for years. They trigger diseases like atherosclerosis – clogging the arteries.’

      ‘So what if I just spend my life relaxing? No stress.’

      ‘Everything we do causes different kinds of stress,’ I said. ‘You can’t stay healthy without some stress. But if we fail at our job, if we’re unlucky in love, if we get sick, if we’re feeling angry or frustrated or sad, our bodies fill with stress hormones. Bacteria and viruses mount challenges to our immune system, and the immune system is more likely to fail. But even if the immune system doesn’t fail, over time, for some reason, we don’t recover as quickly. We accumulate genetic errors in our cells. We deteriorate. We get weaker. The mitochondrial network reads these signs and reports to the deep-tissue bacteria, and the whole conspiracy tattles to the bugs in our gut. The bugs, in turn, tell the mitochondria to work less efficiently. That’s the ultimate cause of aging. Together, they act as judge, jury, and ultimately, executioner.’

      ‘That’s a lot to swallow all at once,’ Montoya said. ‘I’m skeptical about bacteria communicating and cooperating. Don’t they just grow and eat randomly?’

      ‘What kind of toothbrush do you use?’ I asked.

      Montoya shook his head, puzzled. ‘Does it matter?’

      ‘Just tell me.’

      ‘A Sonodyne. I’ve got a big investment in the company.’

      ‘It uses high-frequency vibrating bristles, right?’

      ‘Yeah.’

      ‘There are over five hundred different kinds of bacteria in our mouths,’ I said. ‘Not all of them cause cavities. Some repel or destroy their disease-causing cousins. A healthy mouth is more like the Amazon jungle than a Listerine commercial.’

      Montoya puffed into his palm and sniffed the result. ‘Do I offend?’ he asked, smiling.

      I smiled back. ‘Not at all. But some of them stick to each other and cement themselves to your teeth. After a while, they build up layers of bacterial architecture on your enamel. Dentists call it plaque. It’s a community of cooperating bacteria of many different kinds – a biofilm. The Sonodyne vibrates the biofilm until it falls apart – breaks the cement the bacteria use to fasten to the teeth. In essence, you’re demolishing their houses and shaking them up so bad they can’t even talk.’

      ‘Look, Ma, no cavities,’ Montoya said.

      ‘Other bacterial communities colonize your skin, your mucus membranes, and, of course, your gut, where they perform essential digestive services.’ I could sense myself overstepping the bounds of what my angel might want to hear. ‘There are so many bacteria in your intestines that even people who are starving excrete feces – made up mostly of bacteria.’

      ‘Wow,’ Montoya said. ‘Gossip in the big germ city. But if we’re so important to them, why try to bring us down?’

      ‘A herd of antelopes sheds the old and tired to make way for the young and fit. Lions prune the herd like a rosebush. The lions may act like killers, but actually they’re partners with a big investment in the health of the herd. Bacteria are more than just important partners – they’re the most successful predators of all. We’re their herd. Aging and death is one way to keep the herd fresh and healthy.’

      ‘So, how do bacteria cause aging?’ Montoya asked, leaning forward and moving his tongue over his lips.

      ‘Bacteria in our gut produce quantities of a tiny protein I call hades.’ Now I was really sweating. ‘Our tissues open special receptors, coded for in genes I believe once came from mitochondrial chromosomes. Hades creeps in. It winds up a molecular clock days or weeks after we’re born. With each tick of the clock, the bacteria increase the amount of hades they import into our tissues. Hades alters the way mitochondria work – jams them up, makes them convert ATP with less efficiency. We accumulate the resulting oxidants and free radicals, byproducts of respiration that damage our DNA. Our cells can’t repair the damage. We start to lose our youthful resilience. We grow old.’

      Montoya held up his hand and rubbed a few small, liver-colored patches on the back. ‘Age spots,’ he said. ‘And I’m not that old. So what’s in it for the bacteria?’

      ‘There’s a pot of gold waiting for them. Eventually, we get so weak, so full of genetic errors, that disease or cancer finishes us off. Then, the bacteria have an orgy. They feast like retainers eating a dead king.’

      ‘Jesus,’ Montoya said, and clenched his hand into a fist.

      ‘That’s the work I’ll be publishing in a few months, communication between E. coli and mitochondria in human intestinal cells. I’m leaving out the news about hades for now.’

      ‘We could just kill all our bacteria. Wipe them out with radiation or something. Live in a sterile environment.’

      ‘They tried that in the nineteen twenties, and it didn’t work,’ I said. ‘The fact is, we’re designed to die. The molecular clock also acts like a deadman switch. Without bacteria, we go on aging anyway – only faster. A certain amount of hades may serve double duty – if we’re active and productive, it may even reset the timer on the clock. It may also help repair genetic damage. Without hades, old viruses in our DNA start popping up and antagonizing our immune system. We become more prone to cancer or autoimmune disease.’

      ‘Like a time bomb,’ Montoya said. ‘Awful. I assume you’ve found a way to defuse it?’

      ‘I’m close. The solution isn’t simple, but it involves training bacteria to pump in just the right amount of hades, at the right times – not too much, and not too little. And we have to jam the tattletale signals from our mitochondria. I’m pretty sure I can fool our bacterial partners into turning back our clocks. We live longer – maybe a lot longer.’

      Montoya flexed his fingers and compressed his lips with something like satisfaction. ‘Why go against the wisdom of nature?’ he asked softly, fixing me with a limpid stare. ‘Why live longer than the “judges” want us to?’

      ‘We’re big kids now. We made fire. We made antibiotics. Did the bacteria give us permission to go to the moon? We’re ready to take charge and СКАЧАТЬ