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2016年3月26日 星期六

Bilophila wadsworthia - the harmful anaerobic rod

Bilophila wadsworthia. Source: Lu-Shu Yeh
Our main character today is Bilophila wadsworthia, a Gram-negative anaerobic bacilli.

The word "bilophila" can be split into two parts, bilo- and -phila. The first part of the word "bilo" is originated from bile and that's what it means. It is usually written as "bili-".

The suffix "-phila" is originated from Greek philos, meaning "like".

So the word "bilophila" means "like bile".

Does this anaerobic rod like bile? Yes. Scientists found that the growth of Bilophila wadsworthia can be stimulated by 20% of bile salt and 1% of pyruvate.

According to a paper published in 1997, this anaerobic rod is the third most common anaerobe recovered from clinical material obtained from patients with perforated and gangrenous appendicitis. It is also related to inflammatory bowel disease, including Crohn‘s disease and ulcerative colitis. So it is better for us if we don't have too much of it in our bowels.

Although there is no way to eliminate it from our intestines, studies for intestinal microbiome suggest that eating less fat and more fiber will keep its number low.

References:

Bennion RS. 1990. The bacteriology of gangrenous and perforated appendicitis--revisited. Ann Surg. 211(2):165-71.

 David L.A. et. al. 2014. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 505: 559-563

2016年1月31日 星期日

沃氏嗜膽菌(Bilophila wadsworthia)

今天我們要來介紹給大家認識的是:沃氏嗜膽菌(Bilophila wadsworthia)。
沃氏嗜膽菌。圖:老葉

沃氏嗜膽菌的屬名Bilophila是由字首bilo-與字尾-phila拼起來的:

字首bilo是從拉丁文的bilis變化而來的,意思是膽汁(bile)(請參考第十一課(二)),放在字首寫作bili-;

字尾-phila是由希臘文的philos而來的,意思是喜歡。(請參考第十六課(一))同樣可以表示「喜歡、受吸引」的字尾還有-phil, -phile, -philic, -tropin, -tropism等。

所以Bilophila就是「喜歡膽汁」的意思,不過,這隻菌真的喜歡膽汁嗎?

這隻菌最早是在1988年被鑑定出來,當時是從發生壞疽或穿孔性闌尾炎(gangrenous or perforated appendicitis)的組織中找到它;鑑定了以後發現,這種菌的生長可以被20%的牛膽鹽以及1%的丙酮酸(pyruvate)所刺激。所以,它真的喜歡膽汁呢!

後來的許多研究發現,這種菌會製造硫化氫(H2S),造成腸組織出現發炎的現象。這隻菌也跟炎症性腸病(Inflammatory bowel disease,包括克隆氏症 Crohn‘s disease 與潰瘍性結腸炎ulcerative colitis)的發生有關。也就是說,我們的腸子裡,最好不要有這隻菌的出現呢!

那麼,到底什麼樣的飲食會讓這隻菌出現在我們的腸子裡呢?研究發現,愛吃高脂肪食物的人、以及吃葷的人,他們的腸子裡常常可以找到沃氏嗜膽菌喔!所以還是多吃蔬菜水果對身體比較好呢!

參考文獻:

Bennion RS. 1990. The bacteriology of gangrenous and perforated appendicitis--revisited. Ann Surg. 211(2):165-71.

David L.A. et. al. 2014. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 505: 559-563