WordNet

straightforward in means or manner or behavior or language or action; "a direct question"; "a direct response"; "a direct approach"
having no intervening persons, agents, conditions; "in direct sunlight"; "in direct contact with the voters"; "direct exposure to the disease"; "a direct link"; "the direct cause of the accident"; "direct vote" (同)unmediated
in precisely the same words used by a writer or speaker; "a direct quotation"; "repeated their dialog verbatim" (同)verbatim
(of a current) flowing in one direction only; "direct current"
be in charge of
being an immediate result or consequence; "a direct result of the accident"
command with authority; "He directed the children to do their homework"
direct in spatial dimensions; proceeding without deviation or interruption; straight and short; "a direct route"; "a direct flight"; "a direct hit"
give directions to; point somebody into a certain direction; "I directed them towards the town hall"
guide the actors in (plays and films)
lacking compromising or mitigating elements; exact; "the direct opposite"
moving from west to east on the celestial sphere; or--for planets--around the sun in the same direction as the Earth
similar in nature or effect or relation to another quantity; "a term is in direct proportion to another term if it increases (or decreases) as the other increases (or decreases)"
manageable by a supervising agent; "a directed program of study"
(often used in combination) having a specified direction; "a positively directed vector"; "goal-directed"
an event capable of causing a mutation

PrepTutorEJDIC

『まっすぐな』,一直線の(straight),直進する / (列車などが途中駅に寄らずに)直行 / 直系の / 『直接の』,じかの / 『率直な』,単刀直入の / 全くの,絶対の / 原典どおりの / 『まっすぐに』,直行で / 〈事〉‘を'『指揮する』,監督する / 《文》〈人〉‘に'『命令する』,指図する / 〈人〉‘に'(…への)『道を教える』《+『名』〈人〉+『to』+『名』》 / (…に)〈目・注意・努力など〉‘を'『向ける』《+『名』+『to』(『at, toward』)+『名』(do『ing』)》 / 〈音楽・演劇・映画など〉‘を'『指揮する』,演出する,監督する / (…に)〈手紙など〉‘を'あてる《+『名』+『to』+『名』》

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/13 21:29:01」(JST)

wiki en

[Wiki en表示]

Directed mutagenesis, also known as directed mutation, is a hypothesis proposing that organisms can respond to environmental stresses through directing mutations to certain genes or areas of the genome.

History

The Russian ichthyologist Lev Berg proposed directed mass mutations as the main mechanism for evolution in his anti-Darwinian book Nomogenesis; or, Evolution Determined by Law (1922).^[1] Early studies of "directed mutation" were performed by German geneticists. Richard Goldschmidt in 1929 due to his experiments on drosophila through exposure to elevated temperatures had claimed to have produced evidence for directed mutation. Viktor Jollos (1887-1941) in the 1930s had also carried out experiments on drosophila and written that his results had confirmed Goldschmidt's work which was evidence for direct mutation in contrast to natural selection. However later American geneticists were unable to replicate these experiments.^[2]^[3]

Recent studies

The hypothesis of directed mutagenesis was first proposed in 1988 ^[4] by John Cairns, of Harvard University^[5] who was studying Escherichia coli that lacked the ability to metabolize lactose. He grew these bacteria in media in which lactose was the only source of energy. In doing so, he found that the rate at which the bacteria evolved the ability to metabolize lactose was many orders of magnitude higher than would be expected if the mutations were truly random. This inspired him to propose that the mutations that had occurred had been directed at those genes involved in lactose utilization.^[6]

Later support for this hypothesis came from Susan Rosenberg, then at the University of Alberta, who found that an enzyme involved in DNA recombinational repair, recBCD, was necessary for the directed mutagenesis observed by Cairns and colleagues in 1989.

The directed mutagenesis hypothesis was challenged in 2002, when John Roth and colleagues showed that the phenomenon was due to general hypermutability due to selected gene amplification, and was thus a standard Darwinian process. Later research published in 2006 by Jeffrey D. Stumpf, Anthony R. Poteete, and Patricia L. Foster, however, concluded that amplification could not account for the adaptive mutation and that "mutants that appear during the first few days of lactose selection are true revertants that arise in a single step".

References

^ Levit, Georgy S.; Olsson, Lennart (2006). "Evolution on Rails: Mechanisms and Levels of Orthogenesis". In Wissemann, Volker. Annals of the History and Philosophy of Biology 11. Universitätsverlag Göttingen. pp. 112–3. ISBN 978-3-938616-85-7.
^ Harwood, Jonathan (15 February 1993). "3. Genetics and the Evolutionary Process". Styles of Scientific Thought: The German Genetics Community, 1900–1933. University of Chicago Press. pp. 121–4. ISBN 978-0-226-31882-0.
^ Popov, Igor. "The Problem of Constraints on Variation from Darwin to the Present" (PDF).
^ Cairns J, Overbaugh J, Miller S (September 1988). "The origin of mutants". Nature 335 (6186): 142–5. doi:10.1038/335142a0. PMID 3045565.
^ "John Cairns". Harvard Catalyst Profile.
^ Symonds, N (21 September 1991). "A fitter theory of evolution?: Biologists have always denied that organisms can adapt their genes to suit a new environment. But some startling discoveries about bacteria are making them think again". New Scientist (1787). pp. 30–.
Concar, D (21 September 1991). "A fitter theory of evolution?". New Scientist (1787). p. 30.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 常染色体優性多発性嚢胞腎の遺伝学および嚢胞成長のメカニズム genetics of autosomal dominant polycystic kidney disease and mechanisms of cyst growth
2. インスリン様成長因子 Iの生理学 physiology of insulin like growth factor i
3. 受血者指定供血プログラム directed designated blood donation programs
4. 小児におけるショックの初期マネージメント initial management of shock in children
5. 成人における重症敗血症および敗血症性ショックの評価およびマネージメント evaluation and management of severe sepsis and septic shock in adults

English Journal

Rhizobium etli asparaginase II: An alternative for acute lymphoblastic leukemia (ALL) treatment.

Huerta-Saquero A, Evangelista-Martínez Z, Moreno-Enriquez A, Perez-Rueda E.SourceDepartamento de Microbiología Molecular; Instituto de Biotecnología; Universidad Nacional Autónoma de México; Cuernavaca Morelos, México.
Bioengineered.Bioengineered.2013 Jan 1;4(1). [Epub ahead of print]
Bacterial l-asparaginase has been a universal component of therapies for childhood acute lymphoblastic leukemia since the 1970s. Two principal enzymes derived from Escherichia coli and Erwinia chrysanthemi are the only options clinically approved to date. We recently reported a study of recombinant
PMID 22895060

Species-specific differences in the inhibition of human and zebrafish 11β-hydroxysteroid dehydrogenase 2 by thiram and organotins.

Meyer A, Strajhar P, Murer C, Da Cunha T, Odermatt A.SourceSwiss Center for Applied Human Toxicology and Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland.
Toxicology.Toxicology.2012 Nov 15;301(1-3):72-8. Epub 2012 Jul 11.
Dithiocarbamates and organotins can inhibit enzymes by interacting with functionally essential sulfhydryl groups. Both classes of chemicals were shown to inhibit human 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2), which converts active cortisol into inactive cortisone and has a role in renal and
PMID 22796344

Japanese Journal

Improving the thermal stability of avian myeloblastosis virus reverse transcriptase α-subunit by site-directed mutagenesis.

Konishi Atsushi,Yasukawa Kiyoshi,Inouye Kuniyo
Biotechnology letters 34(7), 1209-1215, 2012-07
… A highly stable AMV RT α-subunit is therefore generated by the same mutation strategy as applied to MMLV RT and that positive charges are introduced into RT at positions that have been implicated to interact with T/P by site-directed mutagenesis. …
NAID 120004247144

A possibility of a protein-bound water molecule as the ionizable group responsible for pKe at the alkaline side in human matrix metalloproteinase 7 activity