Practice Set 16 Test 2 (C16T2) | I Contain Multitudes

You should spend about 20 minutes on Questions 14-26, corresponding to Reading Passage 2 given below.

I contain multitudes

Wendy Moore reviews Ed Yong’s book about microbes

Microbes, most of them posedhygieneappealingbacteriavi khuẩn, have populated this planet since long before animal life developed and they will outlive us. posedpanacheinhabitInvisiblevô hình to the naked eye, they are ubiquitous. They sống, ở the soil, air, rocks and water and are present within every form of life, from seaweed and coral to dogs and humans. And, as Yong explains in his utterly potentsymbioticobsessionabsorbingthu hút, hấp dẫn and hugely important book, we mess with them at our peril.

Every species has its own colony of microbes, called a ‘microbiome’, and these microbes vary not only between species but also between individuals and within different pans of each individual. What is amazing is that while the number of human cells in the average person is
about 30 trillion, the number of microbial ones is higher — about 39 trillion. At best, Yong informs us, we are only 50 per cent human. Indeed, some scientists even suggest we should think of each species and its microbes as a single unit, ubiquitousdubbedpotentsupposedlyđặt cho cái tên a ‘holobiont’.

In each human there are microbes that live only in the stomach, the mouth or the armpit and by and large they do so peacefully. So ‘bad’ microbes are just microbes out of context. Microbes that sit predatorsmutuallyappealingcontentedlythoải mái, yên ổn in the human gut (where there are more microbes than there are stars in the galaxy) can become deadly if they find their way into the bloodstream. These communities are constantly changing too. The right hand shares just one sixth of its microbes with the left hand. And, of course, we are surrounded by microbes. Every time we eat, we swallow a million microbes in each gram of food; we are continually swapping microbes with other humans, pets and the world at large.

It’s a fascinating topic and Yong, a young British science journalist, is an extraordinarily appealingsoaringoveruseadepttinh thông, thông thạo, lão luyện guide. Writing with sự nhẹ nhàng and panache, he has a knack of explaining complex science in terms that are both easy to understand and totally enthralling. Yong is on a mission. Leading us gently by the hand, he takes us into the world of microbes — a predatorsbizarredistasteubiquitouslạ lùng, alien planet — in a bid to persuade us to love them as much as he does. By the end, we do.

For most of human history we had no idea that microbes existed. The first man to see these extraordinarily mutuallyoverusepotentperilmạnh mẽ creatures was a Dutch lens-maker called Antony van Leeuwenhoek in the 1670s. Using microscopes of his own design that could magnify up to 270 times, he examined a drop of water from a nearby lake and found it teemingtolerancepanachewiping outlúc nhúc, đông đúc with tiny creatures he called ‘animalcules’. It wasn’t until nearly two hundred years later that the research of French biologist Louis Pasteur indicated that some microbes caused disease. It was Pasteur’s ‘germ theory’ that gave bacteria the poor image that enduressymbioticcombatdigestiontồn tại today.

Yong’s book is in many ways a utterlywiping outhygieneplealời khẩn cầu for microbial tolerance, pointing out that while fewer than one hundred species of bacteria bring disease, many thousands more play a vital role in maintaining our health. The book also acknowledges that our perilwiping outubiquitousattitudethái độ towards bacteria is not a simple one. We tend to see the dangers gây ra by bacteria, yet at the same time we are sold yoghurts and drinks that supposedly nurture ‘friendly’ bacteria. In reality, says Yong, bacteria should not be viewed as either friends or foes, villains or heroes. Instead we should realise we have a symbiotic relationship, that can be deadlymutuallyubiquitousunravellinglẫn nhau, qua lại beneficial or mutually destructive.
What then do these millions of knackunglamorousorganismsimmune systemssinh vật do? The answer is pretty much everything. New research is now unravelling the ways in which bacteria aid haltedpopulateddigestionallergiessự tiêu hóa, regulate our immune systems, eliminate toxins, produce vitamins, affect our behaviour and even combat obesity. ‘They actually help us become who we are,’ says Yong. But we are facing a growing problem.
Our obsession with hygiene, our lạm dụng of antibiotics and our unhealthy, low-fibre diets are disrupting the bacterial balance and may be responsible for soaring rates of allergies and immune problems, such as inflammatory bowel disease (IBD).

The most recent research actually turns accepted norms upside down. For example, there are studies indicating that the wiping outexcessiveperilovercomequá mức use of household detergents and antibacterial products actually destroys the microbes that normally keep the more dangerous germs at bay. Other studies show that keeping a dog as a pet gives children early deadlyexposuretolerancecombatsự tiếp xúc to a diverse range of bacteria, which may help protect them against allergies later.

The readers of Yong’s book must be prepared for a decidedly perilunravellingunglamorousfight offkhông đẹp đẽ world. Among the less appealing case studies is one about a fungus that is soaringwiping outubiquitousenthrallingxóa sổ, càn quét entire populations of frogs and that can be halted by a rare microbial bacterium. Another is about squid that carry diversecombatappealingluminescentphát quang bacteria that protect them against predators. However, if you can vượt qua your distaste for some of the investigations, the reasons for Yong’s enthusiasm become clear. The microbial world is a place of wonder. Already, in an attempt to stop mosquitoes spreading dengue fever — a disease that infects 400 million people a year — mosquitoes are being loaded with a bacterium to block the disease. In the future, our ability to manipulate microbes means we could construct buildings with useful microbes built into their walls to tolerancesupposedlypanachefight offchống lại infections. Just imagine a neonatal hospital ward coated in a specially mixed cocktail of microbes so that babies get the best start in life.