评论
打印
The largest-known bacterium is changing researchers' ideas about what is possible for bacteria, Earth's most ancient life form.
已知的最大细菌正在改变研究人员有关细菌（地球上最古老的生命形式）可能性的看法。
The organism was discovered on the Caribbean island of Guadeloupe and is big enough to be seen with the human eye.
这种生物是在加勒比海的瓜德罗普岛上发现的，它大到可以用肉眼看到。
Scientists said recently that the bacterium, called Thiomargarita magnifica, is unusual for its size -- up to about two centimeters long.
科学家最近表示，这种名为华丽硫珠菌的细菌的大小不同寻常——大约有两厘米长。
It is also notable because its structure is unlike other bacteria.
值得注意的是，它的结构与其他细菌不同。
The DNA, an organism's genetic information, is not free-moving inside the cell like in most bacteria.
这种细菌的DNA（即生物体的遗传信息）不像大多数细菌那样在细胞内自由移动。
Instead, the DNA is contained within many small membrane-bound sacs.
相反，这种细菌的DNA包含在许多膜结合的小囊中。
Membrane-bound structures in cells are called organelles.
细胞中的膜结合结构叫作细胞器。
Jean-Marie Volland was a co-leader of the study that appeared in the publication Science.
让-玛丽·沃兰德是这项研究的联合负责人，该研究发表在《科学》杂志上。
Volland said of the bacteria, "It is thousands of times larger than regular-sized bacteria.
沃兰德在谈到这种细菌时说：“它比普通大小的细菌大数千倍。
Discovering this bacterium is like encountering a human being as tall as Mount Everest.”
发现这种细菌就像遇到一个和珠穆朗玛峰一样高的人。”
Researchers have found the bacterium in several places in Guadeloupe, a French island group in the Caribbean.
研究人员在瓜德罗普岛的一些地方发现了这种细菌，瓜德罗普岛是位于加勒比海的一个法国群岛。
Study co-leader Olivier Gros first discovered the bacterium in the sulfur-rich seawater of a Guadeloupe swamp - land that is wet and partly covered with water.
研究的共同负责人奥利维尔·格罗斯首先在瓜德罗普沼泽的富硫海水中发现了这种细菌，瓜德罗普沼泽是一片潮湿的土地，有一部分被水覆盖。
Gros described finding long white materials attached to a leaf of a mangrove tree.
格罗斯描述说，他在一棵红树的叶子上发现了长长的白色物质。
He brought the materials back to the lab to study.
他把该物质带回实验室研究。
"Big surprise for me to have so huge a bacterium living in the mangroves of Guadeloupe," he said.
他说：“瓜德罗普岛的红树林里竟然有如此巨大的细菌，这让我大吃一惊。”
A normal bacteria measures one to five micrometers long.
正常的细菌有1到5微米长。
A micrometer is one millionth of a meter.
1微米是百万分之一米。
This species averages 10,000 micrometers or one cm long.
这个物种的平均长度为1万微米（即1厘米）长。
Some Thiomargarita magnifica are double that length.
一些华丽硫珠菌的长度是这个长度的两倍。
Volland said the bacterium is bigger “than what we thought was the maximum possible size for a single bacterium."
沃兰德说，这种细菌比我们所认为的单个细菌可能的最大尺寸还要大。
He added, "They are about the same size and shape of an eyelash."
他还说，“它们的大小和形状和睫毛差不多。”
The largest-known bacterium until now had a maximum length of around 750 micrometers.
到目前为止，已知的最大细菌最长约为750微米。
Bacteria are single-celled organisms that live nearly everywhere on Earth.
细菌是单细胞生物，地球上几乎所有地方都有细菌。
Bacteria are thought to have been the first organisms and remain very simple in structure billions of years later.
细菌被认为是地球上最早出现的生物，数十亿年后，它们的结构仍然非常简单。
The bodies of humans are filled with bacteria.
人类的身体里充满了细菌。
Only a small number of these cause disease.
其中只有一小部分会导致疾病。
Caribbean mangrove swamps are filled with organic material.
加勒比海红树林沼泽充满了有机物。
Microbes break down this material and produce sulfur.
微生物分解这种物质并产生硫。
The sulfur-rich environment offers an energy source for bacteria like Thiomargarita magnifica.
富含硫的环境为诸如华丽硫珠菌之类的细菌提供了能源来源。
The researchers named its DNA-holding organelles "pepins" after a French word for small seeds inside fruits.
研究人员将其携带DNA的细胞器命名为“pepins”，这是一个法语单词，意思是水果中的小种子。
"Aside from two exceptions, there were no other bacteria known to keep their DNA inside a membrane-bound organelle.
沃兰德说：“除了两个例外，没有其他已知的细菌将它们的DNA保存在膜结合的细胞器内。
That is, in fact, a characteristic of more complex cells which have a membrane-bound nucleus, such as human cells, or animal and plant cells," Volland said.
事实上，这是具有膜结合细胞核的更复杂细胞（如人类细胞或动植物细胞）的特征。”
A genome map showed that Thiomargarita magnifica has lost some genes needed for cell division and has more than the usual number of copies of genes responsible for cell lengthening.
基因图谱显示，华丽硫珠菌已经失去了一些细胞分裂所需的基因，拥有了比通常数量更多的负责细胞变长的基因副本。
"The genome is also very big and contains three times the average number of genes that are usually found in bacteria. Half of those genes, we have no idea what are they for," Volland said.
沃兰德说：“这种细菌的基因组也非常大，包含的基因数量是通常在细菌中发现的平均基因数量的三倍。其中一半的基因，我们不知道它们是用来干什么的。”
This bacterium shows how life on Earth still has surprises awaiting discovery, he said.
他说，这种细菌说明了地球上的生命仍然有许多惊喜等待发现。
"Life is fascinating, very diverse and very complex," Volland added.
沃兰德还说：“生命是迷人的、非常多样化的和非常复杂的。”
"It's important to stay curious and have an open mind."
“保持好奇和开放的心态很重要。”
I’m John Russell.
约翰·拉塞尔为您播报。
译文为可可英语翻译，未经授权请勿转载！
