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Remember that these cells are relatively large compared to bacteria and so diffusion doesn't occur very quickly over this length scale.
要知道这些细胞相对细菌而言,还是比较大的,扩散作用在这种尺度上,发生得不是那么快
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When they do that they can actually engulf the bacteria in a process called phagocytosis and break them down into antigens.
免疫细胞确实是将细菌整个吞进了肚内,这一过程称为吞噬作用,并将细菌分解成小抗原
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You sneeze because you've got all these germs inside you and your body wants to get the germs out, so you sneeze.
你打喷嚏，因为细菌在你体内,你的身体想把他们赶出去，所以你打喷嚏。
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So look, why am I justified in believing in germs, various kinds of viruses that I can't see, or bacteria or what have you, that I can't see?
所以,我为什么相信微生物,相信各种肉眼无法看到的病毒,细菌等诸如此类我看不到的东西确实存在
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So, not just a spectrum of viruses, but there's viruses and bacteria and parasites and other microorganisms that can cause disease.
所以,不是只有病毒,还有病毒,细菌,寄生虫,和其它各种微生物都能导致疾病
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So, you're familiar with some of these bacteria like salmonella, or the micro bacterium that causes tuberculosis are shown here.
所以 你们很熟悉像沙门氏菌这样的细菌,或者像这儿的引起结核的小细菌
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Get a gene, put it in a plasmid, get that plasmid expressed in a host, could even be a bacterial host,right?
把一个基因导入一个质粒,让质粒在宿主中表达,这个宿主甚至可以是细菌,对吧
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Bacterial cells are small, one to two microns in diameter and this shows a picture of a common bacterium called E. Coli.
细菌细胞很小,直径只有一到两个微米,这张图片是一种常见细菌,大肠杆菌
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Movement down a concentration gradient occurs fairly rapidly over short distances like a micron or so, like the size of a bacterium.
顺浓度梯度扩散在一微米左右的短距离内,相当迅速,一微米相当于一个细菌的大小
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The bacterium doesn't have a nucleus, and in fact, they don't have very well formed organelles in general.
细菌没有细胞核,实际上,细菌没有完善的细胞器
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So, I have a bacteria infection, stimulates my immune system, I start making antibodies that bind to an antigen specific to that bacteria.
所以 如果我被细菌感染了,我的免疫系统被激活,开始制造抗体,这些抗体结合到细菌特异性的抗原上
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Because bacteria are outside of cells and when antibodies bind to them they can neutralize them.
因为细菌生存在细胞外,抗体结合细菌并中和掉它们
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It's much larger than a bacterium, it's ten to 30 microns let's say instead of one to two microns, so almost ten times bigger.
人类细胞比细菌大得多,有十到三十微米那么大而不是一两微米,几乎大了十倍
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The study of immunology is the study of mechanisms that your body uses to protect itself from mainly from foreign pathogens like viruses and bacteria.
免疫学研究身体,采用何种机制来保护自身,免受外源病原体如病毒和细菌的伤害
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The innate immune system composed of neutrophils and macrophages; these are cells that are crawling around your body all the time ready to eat bacteria.
它由嗜中性粒细胞和巨噬细胞构成,这些细胞不断在周身蠕行,准备吞噬细菌
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Hopefully each one of those cells is containing one or more of the plasmids that you're interested in and those are being copied as well.
如果顺利的话每个细菌里都含有,一个或更多我们所感兴趣的质粒,而它们也正在被复制
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From this person--this perspective, a person is just a germ's way of making other germs.
从这个角度看，这个人，人来只是细菌繁殖的方式。
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Won't help me against other bacteria, but only against the one that I've got.
但对其他细菌却不起作用,只能抵抗我感染到的这种细菌
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Why don't bacteria need a distinct nucleus and that's necessary in a human cell?
为什么细菌不需要单独的细胞核,而对人类细胞则为必需
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They're fully functional organisms that can reproduce on their own, and they can start growing outside of any cell and that's what they do, they live extracellularly.
细菌可是麻雀虽小五脏俱全,它们能够凭借自身繁殖,可以在任意一个细胞外开始增殖,它们就是这样做的,在细胞外生长繁殖
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Well, you could think about the cell wall of a bacterium as its skeleton, it's what protects it from mechanical forces that are out in the world.
你可能认为细菌的细胞壁,就像骨骼一样,使其免受,外界机械力的伤害
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Antibiotics are chemicals, usually small organic molecules that will kill micro-organisms like bacteria.
抗生素是一类化学物质,它们通常是小分子有机物,能够杀死细菌这样的微生物
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If you're a bacterium your whole life is about swimming to nutrients and running away from things that would kill you.
假如你是一个细菌,你的一生将会在追逐养分,和逃避敌害中度过
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One way is to allow these bacteria to grow on a plate that is loaded with antibiotics like Ampicillin.
一种方法,是让这些细菌,在有大量抗生素如氨苄青霉素,的培养基上生长
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So you could use sort of negative selection in order to find the ones that you want.
这样你就可以用某种负向选择,去找到你想要的细菌
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If your gene goes in, you've interrupted the gene for antibiotic resistance and those new organisms aren't going to be resistant to antibiotic anymore.
如果基因进入了质粒,原本对抗生素有抗性的基因就被打断了,那些新细菌就不再对抗生素有抗性
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This is a bacterium that's normally present in humans; it colonizes all of our intestinal systems.
这种细菌在人体中很常见,栖居在我们所有人的肠道系统中
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What are some of the differences between a bacterial cell and a human cell?
人类细胞和细菌细胞,有哪些不同之处呢
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Cells that I took from a human and cells that are in a bacterium.
人类细胞,和细菌细胞
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In this particular example here we're exposing these plasmids to bacterial cells.
我举一个特别的例子,我们把这些质粒暴露给细菌
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