VOA慢速英语 | Health Report沙门氏菌可杀死癌细胞
摘要: 沙门氏菌是一种常见食源性致病菌,通常引起食物中毒或伤寒,但经基因改造后可在实验中特异性靶向并杀死癌细胞,而不伤害健康组织。
- 沙门氏菌通常被视为有害细菌,可导致发热、腹痛和呕吐等食物中毒症状。
- 科学家通过基因工程改造沙门氏菌,使其无法在健康组织中存活,但能富集于肿瘤并杀死癌细胞。
- 该方法已在小鼠实验中验证,尚处于临床前研究阶段,尚未用于人体治疗。
- 未来可能作为辅助疗法,与化疗或放疗联合使用,而非独立抗癌手段。
- 相关研究成果已发表于医学期刊《mBio》。
小白老师说:前面推送的VOA慢速英语Health Report健康报道很受大家的欢迎,所以今天继续。大家更喜欢什么内容,可以发信息给我。另外,听力原文后面给出的译文来自于网络,我看了一下,翻得很烂的那种,大家凑合看吧,好歹能帮助扫清一下生词。
From VOA Learning English, this is the Health and Lifestyle Report.
Not many people consider a bacterium that makes millions of people sick a friend. But scientist Roy Curtiss does.
“Yeah, I’m always looking for new uses for a bug that most people think is an enemy – it’s my friend. And I would like to make it your friend too.”
Roy Curtiss is a microbiologist at the Biodesign Institute at Arizona State University in Tempe, Arizona. He uses the word ‘bug,’ a common expression for a germ or virus, when talking about Salmonella bacteria.
Mr. Curtiss studies Salmonella and thinks it “gets a bad rap.” In other words, many people only have bad thoughts when they hear the word, “Salmonella.”
What is Salmonella?
Salmonella is the most common bacteria to harm, or contaminate, food. It is found in undercooked meats, eggs and milk. Salmonella can cause a higher than normal body temperature and pain in the abdomen. The person may feel sick, throwing up whatever is in the stomach.
One form of Salmonella is also responsible for the disease typhoid.
So, it is only natural that a bacterium that makes people sick is given a bad rap. The question is, “When does a food-borne bacterium become your friend?” The answer: when it helps to kill cancer cells.
“The enemy of my enemy is my friend.”
Millions of people are sickened each year by Salmonella. But a genetically-engineered version of the bacteria may someday be used as a weapon against cancer. As the old saying goes, “The enemy of my enemy is my friend.”
Researchers in the United States and Germany have turned Salmonella into a weapon against cancerous tumors. Roy Curtiss says the bacteria can make the cancer cells disappear.
The experiment
And here is the experiment. First, the researchers changed the genes of the Salmonella to die in healthy tissues but kill cancer cells. They put human cancer cells into mice. Then, he says, they put the genetically-modified Salmonella bacteria into the animals.
“We genetically modify the Salmonella so that it is unable to survive in healthy tissues, but has a preferential homing (attraction) to tumors, which [are] a very nutrient-rich environment where they grow like crazy and, in so doing, kill the cancer cells within the tumor.”
A report describing the work was published in the medical journal mBio.
Roy Curtiss says it will be a while before the genetically-modified version of Salmonella is tested on human beings. He wants to make more changes to the bacteria to increase their cancer-killing power.
Salmonella would not be a stand-alone treatment for fighting cancer. Instead, Mr. Curtiss hopes the genetically-modified bacteria will be used in addition to more traditional therapies, such as chemotherapy and radiation.
I’m Anna Matteo.
很多人都不会把让成千上万的人生病的细菌当做朋友,但是科学家Roy Curtiss却会这样做。
“是的,我总是寻找大家经常认为是敌人的细菌的一些新用途,它是我的朋友。我也想让大家能和它做朋友。”
Roy Curtiss是亚利桑那州一家生物设计研究所的微生物学家。在我们讨论沙门氏菌的时候他用“虫子”这个常见的字眼来表示细菌和病毒。
Curtiss专门研究沙门氏菌,并认为人们给它扣了一个“坏名声”。换言之,很数人听到沙门氏菌的时候想到的都是坏的方面。
什么是沙门氏菌?
沙门氏菌是对食物来讲最常见的细菌或者污染物,存在于一些未煮熟的肉类,鸡蛋和牛奶中。沙门氏菌可以引起身体发热和腹部疼痛。患者可能会感到恶心和呕吐。
其中一种沙门氏菌种还会造成伤寒病。
因此人们才会很自然的认为这种细菌能够给人类带来疾病,从而背上了坏名声。问题是:"何时食源性细菌才能成为你的朋友?"答案:当它可以帮助人类杀死癌细胞的时候。
“敌人的敌人是朋友。”
每年有数百万的人因沙门氏菌生病,但是经过基因转换工程后的沙门氏菌在未来的某一天可以被用来作为消灭癌症的武器。就像一句古话所说:“我敌人的敌人,就是我的朋友。”
美国和德国的研究人员已经把沙门氏菌转化称了对抗肿瘤癌症的武器。Roy Curtiss称这种细菌可以使癌细胞消失。
实验
这是一个实验。首先,研究人员改变了沙门氏菌的内部基因转而去杀死癌细胞。研究人员向老鼠体内注射了人类癌细胞。然后他说,他们将转换过基因的沙门氏菌注射到动物体内。
我们对沙门氏菌进行了基因修改使其无法在健康组织中正常生存,但是肿瘤对于这些基因来讲是一个很好的生存条件,这是一个富有营养的环境他们可以疯狂的生长,然后就可以发挥修改过基因的沙门氏菌的作用来杀死癌细胞。
一份报告称这一研究发表在了医学杂志mBio上。
Roy Curtiss说在人类身上进行修改过的沙门氏菌基因实验还需要等一段时间。他希望能够对细菌进行更多修改来增强其抗癌作用。
沙门氏菌不会是对抗癌症的唯一疗法。相反,Curtiss先生希望修改过的细菌基因研究将会更广泛地应用到传统疗法当中,例如化疗和放射疗法。
我是Anna Matteo。
常见问题
沙门氏菌真的能用来治疗癌症吗?
目前仅在动物实验中证实经基因改造的沙门氏菌可靶向肿瘤并杀死癌细胞,尚未进入人体临床应用阶段。
为什么沙门氏菌能攻击癌细胞而不伤害正常细胞?
研究人员对其进行了基因改造,使其无法在健康组织中生存,但能在营养丰富的肿瘤微环境中增殖并发挥抗癌作用。
这种疗法会取代化疗或放疗吗?
不会。研究者Roy Curtiss表示,该方法旨在作为传统疗法(如化疗和放疗)的补充,而非替代。
沙门氏菌原本会导致什么疾病?
沙门氏菌可引起食物中毒,症状包括发热、腹痛、呕吐;某些血清型(如伤寒沙门氏菌)还会导致伤寒。
参考资料
Genetically Engineered Salmonella as a Cancer Therapeutic
研究由亚利桑那州立大学Biodesign研究所的Roy Curtiss团队开展,成果发表于期刊mBio。