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主题:【原创】【整理】致高尔夫、南方系,并安慰忘情兄 -- 巅峰背影

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家园 又想当然了, BT菌是土壤里的细菌

没有人类折腾, 不会天然到草上, 菜上的。


本帖一共被 1 帖 引用 (帖内工具实现)
家园 多谢老兄正本清源
家园 想当然?1911年发现Bt菌,是在面粉的虫子里

地中海粉螟,产卵于幼虫的食物里,幼虫从一出生就生活在面粉堆里,它们从哪里吃到的Bt菌呢?它们吃得到,人吃得到吗?

以下是若干文献,说明Bt菌在自然界植物以及植物制品上的广泛分布:

[URL=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC182704/]The Phylloplane as a Source of Bacillus thuringiensis Variants

[/URL]

《叶面是Bt菌变种的来源》

在针叶和落叶林的叶面上分离到Bt菌。这些Bt菌对毛虫有毒性。

Novel variants of Bacillus thuringiensis were isolated from the phylloplane of deciduous and conifer trees as well as of other plants. These isolates displayed a range of toxicity towards Trichoplusia ni. Immunoblot and toxin protein analysis indicate that these strains included representatives of the three principal B. thuringiensis pathotypes active against larvae of the orders Lepidoptera, Diptera, and Coleoptera. We propose that B. thuringiensis be considered part of the common leaf microflora of many plants.

[URL=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC195596/]

Distribution, Frequency, and Diversity of Bacillus thuringiensis in an Animal Feed Mill[/URL]

《Bt菌在一个动物饲料磨坊里的分布,频率和多样性》

在一个动物饲料磨坊里分离到Bt菌。其中一些产生delta-toxin

Bacillus thuringiensis was isolated from 36 of 50 residue samples obtained from an animal feed mill (a stored-product environment). Of 710 selected colonies having Bacillus cereus-B. thuringiensis morphology isolated from the samples, 477 were classified as B. thuringiensis because of production of parasporal δ-endotoxin crystals. There was a diverse population of B. thuringiensis, as revealed by differentiation of the isolates into 36 subgroups by using (i) their spectra of toxicity to the lepidopterans Heliothis virescens, Pieris brassicae, and Spodoptera littoralis and the dipteran Aedes aegypti and (ii) their parasporal crystal morphology. A total of 55% of the isolates were not toxic to any of these insects at the concentrations used in the bioassays; 40% of all isolates were toxic to one or more of the Lepidoptera; and 20, 1, and 1% of the isolates were toxic to only P. brassicae, H. virescens, and S. littoralis, respectively. The most frequent toxicity was toxicity to P. brassicae (36% of all isolates); 18% of the isolates were toxic to A. aegypti (5% exclusively), 10% were toxic to H. virescens, and 4% were toxic to S. littoralis. Toxicity to P. brassicae was more often linked with toxicity to H. virescens than with toxicity to S. littoralis. The frequency of toxicity was significantly greater in isolates that produced bipyramidal crystals than in isolates that produced irregular pointed, irregular spherical, rectangular, or spherical crystals.

[URL=http://www.ots.ac.cr/tropiweb/attachments/volumes/vol54-2/04-RODRIGUEZ-Bacillus.pdf]

Bacillus thuringiensis in caterpillars and associated materials collected from protected tropical forests in northwestern Costa Rica

[/URL]

《哥斯达黎加西北部热带保育森林里的毛虫和相关物体上采集到的Bt菌》

在哥斯达黎加的森林里的叶片,毛虫肠和粪便中分离到Bt菌

Abstract. Bacillus thuringiensis (Bt) synthesizes crystalline inclusions that are toxic to caterpillars (Lepidoptera)

and other orders of invertebrates. Materials associated with 37 caterpillars from 16 species, collected while feeding

on 15 different species of host plants in dry, cloud and rain forests located in the rea de Conservación

Guanacaste in northwestern Costa Rica, were examined for the presence of Bt. From a total of 101 derived

samples, 25 Bt isolates were cultured: 56% from host plant leaves, 8% from caterpillar guts and 36% from caterpillar

fecal pellets. Bt was isolated from at least one sample in 38% of the systems constituted by the food plant,

gut and fecal pellets corresponding to a single caterpillar. Four different morphologies of crystalline inclusions

were observed, with bipyramidal and irregular crystal morphologies being the most prevalent. Rev. Biol. Trop.

54(2): 265-271. Epub 2006 Jun 01.

Natural Isolates ofBacillus thuringiensis:Worldwide Distribution, Characterization, and Activity against Insect Pest

《Bt菌的自然分离株: 世界范围内的分布,定性,以及对昆虫害虫的活性》

来自于80个国家的5303个自然样品里分离到的Bt菌,45%来自于储存的产品,25%来自于土壤。抗昆虫活性物含量最高的样品是磨菇和储藏的产品……

Abstract

Bacillus thuringiensiswas isolated from natural samples collected from 80 countries. The majority, 45% of the 5303 isolates, originated from stored products, with 25% originating from soil. The materials richest in isolates active in insects were mushroom compost and stored products. The proportion with bipyramidal-shaped crystals was 46%, while among the range of other shapes 14% were spherical and 4% rectangular. The largest proportion of isolates, 45%, was found in the United Kingdom with the majority originating from stored mills, which import produce from all over the world; 22% came from North America. Using single-dose assays, 44% of the isolates killed less than 25% of larvae of all four Lepidoptera tested,Heliothis virescens, Pieris brassicae, Spodoptera littoralis,andAgrotis ypsilon.Among isolates killing more than 25% of the larvae, every combination of activities of the 16 possible against these 4 insects was found, in proportions ranging from 0.6 to 14.5%, suggesting considerable diversity of insect activity. The 44% of strains with little or no activity to Lepidoptera (<25% mortality) included strains selectively active against Diptera and Coleoptera. An analysis of activity using one representative species from each of the three orders of insectsH. virescens, Aedes aegypti,andPhaedon cochleariaeshowed 48.8% of strains to be inactive (<25% mortality) in all three, with 1.2 to 14.6% active in the other 7 possible combinations. For an analysis of geographical origins of insect activity, 3 species (P. cochleariae, S. littoralis,andH. virescens) were chosen with susceptibility to different δ-endotoxins. With one exception, activity did not appear to be correlated with origin, indicating a relatively ubiquitous distribution of the selected activities and ofB. thuringiensisin general. The worldwide spread and evolution of this insect pathogen and its different types are discussed in relation to geographical origin and source materials, as well as possible interaction with other bacteria.

Isolation, distribution and toxicity of Bacillus thuringiensis from warehouses in China

《来自于中国仓库的Bt菌的分离,分布与毒性》

在413个来自于谷仓,加工工厂和饲料厂的粉尘和死虫样品中,有122个样品里分离到了Bt菌。其中在存放米糠和麻袋装米的仓库的粉尘里分离到的样品最多。

Using acetate selection to screen dust samples and cadavers of insect, Bacillus thuringiensis was isolated from 122 of 413 samples obtained from various warehouses, processing facilities and animal feed mills. Abundance of B. thuringiensis in the settled dust samples of different origins was different. Among them, B. thuringiensis were most abundant in the settled dust samples from warehouses storing rice bran and gunny-bag, in which 46 and 50% of samples contained B. thuringiensis, respectively. The B. thuringiensis in samples from mountainous region and hilly country were more abundant than that from lowland areas, in which 41 and 20% of samples contained B. thuringiensis, respectively. These B. thuringiensis isolates belonged to serotypes H3, H4, H5, H7, H8, H10, H23 and H27. Among them, serotypes H4 and H5 were most abundant and amounted to 36 and 24% of isolates, respectively. The B. thuringiensis from different types of warehouses and regions was different in terms of H-serotype. There is rich diversity of toxicity to insects in B. thuringiensis isolates from warehouses; 58 and 71% of the isolates were toxic to larvae of Plodia interpunctella and Spodoptera exigua, respectively, causing more than 60% mortality. Most isolates were not toxic to Phaedon brassicae and Culexpipiens fatigans; only one isolate was highly toxic, causing more than 90% mortality to both species.


本帖一共被 1 帖 引用 (帖内工具实现)
家园 我把回复弄到科技探索去了,发了个主贴

这里已经看不出发贴的层次,再说对楼主的主题也是严重的歪楼。欢迎去新帖继续讨论:

王二狗:Bt菌在自然界里的存在,是否仅仅限于土壤

家园 俺补充了一点

链接出处

家园 回复了个,补充了一点,从大力丸的角度

链接出处

家园 小龙虾也是蛋白质哦

链接出处

家园 你看明白我说什么再回复好不好
家园 哎!如此没有耐心,且不喜欢插科打诨,不好玩

你看了我回复啥,再回复好不好?

家园 我粗略看了一下,没啥好评价的

我挑了一个最明显的问题,那个问题跟你这里所嘲笑的方舟子不知什么是内毒素,基本是一个水平。

剩下的我就不评价了,我大学毕业很多年了,对大专辩论会早没兴趣了。

家园 谢谢抬举,俺和方舟子位列一个集团。拱手中,呵呵

如果说不客气点嘛,你根本没看懂我那篇主要在说啥。

家园 你的态度很严谨,研究很认真,花上

不过提两点:1,转基因植物里,据我所知是不用cyt蛋白的,都是用cry蛋白。所以仅仅从肠道受体这个方面考虑,的确cry蛋白在人体里不会像在昆虫肠道里那样先结合受体再破坏细胞膜,也就是说特异性的毒性要低很多。

至于cry在没有受体介导的情况下,能不能结合细胞膜,结合细胞膜之后的毒性是否还比较强,这个我就不清楚了。

不过这的确说明仅仅因为人体内没有受体就说cry蛋白绝对安全,这是不谨慎的。胃功能障碍的食用者如果大量食入cry蛋白,很难说会出现什么情形。

2,Bt感染虫子之后,首先是肠壁细胞膜功能被毒蛋白破坏,在细胞膜上会有孔洞形成,这个穿孔和肠穿孔完全不是一回事,这你说得很对。

不过虫子的肠壁因为细胞大量坏死,最终的确要穿孔的,这能不能叫“肠穿孔”我不确定,因为就像你说的,肠穿孔是医学上一个特有概念。不过最后虫子的肠壁最终的确要破裂,然后细菌和芽孢会从破裂的地方进入虫体,造成败血症(我不知道这个词用得对不对,英文里是这么说的,septicemia)。这是虫子死亡的直接原因。

别的,除了对方的个人评价,都同意你。本来是准备完全同意的,后来想到,对方个人呢,除了道听途说的一些信息外,我对他这个人没啥研究,所以还是暂不同意比较合适

家园 我水平差嘛
家园 这个就见仁见智,各自保留看法吧
家园 方的一些说法很令人生疑

作为一个曾经的科学工作者,他如此信誓旦旦地为转基因打包票,比真正做转基因安全性研究的人还信心百倍,不由得人不怀疑他的立场是否真正公正。一个合格的研究人员在做陈述时,是不会忘记说研究的前提条件的。

加拿大有研究人员发现bt毒素引起新生儿肠道综合症引起穿肠。

外链出处

且不说是否这两者有直接因果关系,单就婴儿血液里发现bt毒素这一点,就足以让人震惊的了。不是说煮熟了就失活了么?不是说在胃酸里会完全分解么?不是说人没有受体么?怎么还会有带活性的毒素存在呢?怎么会进入婴儿血液造成穿肠呢?

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