Formation of New Species

Formation of New Species tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh vực kin...

New application of firefly luciferase ) it can catalyze the enantioselective thioester formation of 2-arylpropanoic acid Dai-Ichiro Kato 1 , Keisuke Teruya 1 , Hiromitsu Yoshida 1 , Masahiro Takeo 1 , Seiji Negoro 1 and Hiromichi Ohta 2 1 Graduate School of Engineering, University of Hyogo, Japan 2 Department of Biosciences and Informatics, Keio University, Japan Firefly luciferase is a well-known enzyme that concerns in the bioluminescence reaction. It catalyzes the oxida- tion of firefly luciferin with molecular oxygen in the presence of ATP and Mg 2+ , resulting in luminescence [1–3]. The stereoselectivity of this bioluminescent reac- tion was investigated in detail by Seliger et al. [4], who found that the d-form is the specific substrate for the light emission reaction whereas the l-form is not used for the light-producing reaction. The bioluminescence reaction of firefly luciferase is composed of two reac- tion steps. The first step is the activation of the carb- oxyl group to form luciferyladenylate and the second is the light emission reaction via the oxidation of this intermediate. The substrate activation mechanism in the initial step is commonly observed in adenylate- forming enzymes, such as aminoacyl-tRNA synthetases, Keywords acyl-CoA synthetase; enantiomer; firefly luciferase; kinetic resolution; nonsteroidal anti-inflamatory drugs Correspondence D I. Kato, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2201, Japan Fax: +81 79 267 4891 Tel: +81 79 267 4969 E-mail: kato@eng.u-hyogo.ac.jp (Received 22 February 2007, revised 4 June 2007, accepted 5 June 2007) doi:10.1111/j.1742-4658.2007.05921.x We introduce a new application of firefly luciferase (EC 1.13.12.7). The firefly luciferases belong to a large superfamily that includes rat liver long- chain acyl-CoA synthetase (LACS1). LACS1 is the enzyme that is involved in the deracemization process of 2-arylpropanoic acid and catalyzes the enantioselective thioester formation of R-acids. Based on the similarity of the reaction mechanisms and the sequences between firefly luciferase and LACS1, we predicted that firefly luciferase also has thioesterification activ- ity toward 2-arylpropanoic acid. From an investigation using three kinds of luciferases from North American firefly and Japanese fireflies, we have confirmed that these luciferases exhibit an enantioselective thioester forma- tion activity and the R-form is transformed to a thioester in preference to the S-form in the presence of ATP, Mg 2+ , and CoASH. The enantiomeric excesses of unreacted recovered acid and thioester were determined by chi- ral phase HPLC analysis and the resulting 2-arylpropanoyl-CoAs were identified by high resolution mass spectroscopy. The K m and k cat values of thermostable luciferase from Luciola lateralis (LUC-H) toward ketoprofen were determined as 0.22 mm and 0.11 s )1 , respectively. The affinity of keto- profen was almost the same of d-luciferin. In addition, the calculated E-value toward ketoprofen was approximately 20. These results suggest that LUC-H could catalyze the kinetic resolution of 2-arylpropanoic acid efficiently and would be a new option for the preparation of optically act- ive 2-substituted carboxylic acids. Abbreviations ACS, acyl-CoA synthetase; ee, enantiomeric excess; fenoprofen, 2-(3-phenoxyphenyl)propanoic acid; flurbiprofen, Formation of New Species Formation of New Species Bởi: OpenStaxCollege Although all life on earth shares various genetic similarities, only certain organisms combine genetic information by sexual reproduction and have offspring that can then successfully reproduce Scientists call such organisms members of the same biological species Species and the Ability to Reproduce A species is a group of individual organisms that interbreed and produce fertile, viable offspring According to this definition, one species is distinguished from another when, in nature, it is not possible for matings between individuals from each species to produce fertile offspring Members of the same species share both external and internal characteristics, which develop from their DNA The closer relationship two organisms share, the more DNA they have in common, just like people and their families People’s DNA is likely to be more like their father or mother’s DNA than their cousin or grandparent’s DNA Organisms of the same species have the highest level of DNA alignment and therefore share characteristics and behaviors that lead to successful reproduction Species’ appearance can be misleading in suggesting an ability or inability to mate For example, even though domestic dogs (Canis lupus familiaris) display phenotypic differences, such as size, build, and coat, most dogs can interbreed and produce viable puppies that can mature and sexually reproduce ([link]) 1/14 Formation of New Species The (a) poodle and (b) cocker spaniel can reproduce to produce a breed known as (c) the cockapoo (credit a: modification of work by Sally Eller, Tom Reese; credit b: modification of work by Jeremy McWilliams; credit c: modification of work by Kathleen Conklin) In other cases, individuals may appear similar although they are not members of the same species For example, even though bald eagles (Haliaeetus leucocephalus) and African fish eagles (Haliaeetus vocifer) are both birds and eagles, each belongs to a separate species group ([link]) If humans were to artificially intervene and fertilize the egg of a bald eagle with the sperm of an African fish eagle and a chick did hatch, that offspring, called a hybrid (a cross between two species), would probably be infertile—unable to successfully reproduce after it reached maturity Different species may have different genes that are active in development; therefore, it may not be possible to develop a viable offspring with two different sets of directions Thus, even though hybridization may take place, the two species still remain separate The (a) African fish eagle is similar in appearance to the (b) bald eagle, but the two birds are members of different species (credit a: modification of work by Nigel Wedge; credit b: modification of work by U.S Fish and Wildlife Service) Populations of species share a gene pool: a collection of all the variants of genes in the species Again, the basis to any changes in a group or population of organisms must be genetic for this is the only way to share and pass on traits When variations occur within a species, they can only be passed to the next generation along two main pathways: asexual reproduction or sexual reproduction The change will be passed on asexually simply if the reproducing cell possesses the changed trait For the changed trait to be passed on by sexual reproduction, a gamete, such as a sperm or egg cell, must possess the changed trait In other words, sexually-reproducing organisms can experience several genetic changes in their body cells, but if these changes not occur in a sperm or egg cell, the changed trait will never reach the next generation Only heritable traits can evolve Therefore, reproduction plays a paramount role for genetic change to take root in a population or species In short, organisms must be able to reproduce with each other to pass new traits to offspring 2/14 Formation of New Species Speciation The biological definition of species, which works for sexually reproducing organisms, is a group of actually or potentially interbreeding individuals There are exceptions to this rule Many species are similar enough that hybrid offspring are possible and may often occur in nature, but for the majority of species this rule generally holds In fact, the presence in nature of hybrids between similar species suggests that they may have descended from a single interbreeding species, and the speciation process may not yet be completed Given the extraordinary diversity of life on the planet there must be mechanisms for speciation: the formation of two species from one original species Darwin envisioned this process as a branching event and diagrammed the process in the only illustration found in On the Origin of Species ([link]a) Compare this illustration to the diagram of elephant evolution ([link]b), which shows that as one species changes over time, it branches to form more than one new species, repeatedly, as long as the population survives or until ...The structure of the O-chain of the lipopolysaccharide of a prototypal diarrheagenic strain of Hafnia alvei that has characteristics of a new species under the genus Escherichia Reine Eserstam 1 , Thushari P. Rajaguru 1,2 , Per-Erik Jansson 1 , Andrej Weintraub 3 and M. John Albert 4 1 Clinical Research Center, Analytical unit, Karolinska Institute, Huddinge Hospital, Huddinge, Sweden; 2 Department of Chemistry, University of Peradeniya, Peradeniya, Sri Lanka; 3 Karolinska Institute, Department of Microbiology, Pathology and Immunology, Division of Clinical Bacteriology, Huddinge University Hospital, Sweden; 4 Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait The structure of the O-polysaccharide of the lipopolysac- charide from a diarrheal strain isolated in Bangladesh was studied with sugar, and methylation analysis, NMR spectroscopy, mass spectrometry and partial acid hydrolysis. The strain was first designated as Hafnia alvei, but later found to be a possible new species in the genus Escherichia. Two different polysaccharides were detected, a major and a minor one. The structure of the major polysaccharide is gi- ven below, while the structure of the minor one was not investigated. The structure of the repeating unit was estab- lished as →6)-β- D -Galf-(1→3)-β- D -GalpNAc-(1→3)-β- D -Galp-(1→ α-NeuAc ↑ 6 2 The structure does not resemble any of the previously investigated lipopolysaccharide O-chains from Escherichia coli or H. alvei, but could fit in either group based on types of sugar residues and acidity. Phenotypic microbiological studies cannot definitely assign it to either species of the two genera. Genetic hybridization studies indicate that the Bangladeshi isolates may require a new species designation under the genus Escherichia. Keywords: lipopolysaccharide; Escherichia; Hafnia alvei; diarrhea; neuraminic acid. Hafnia alvei is a Gram negative bacterium and a member of the family Enterobacteriaceae. There are reports of associ- ation of H. alvei with diarrhoea in Canada [1] and Finland [2], but the mechanism of diarrhoea caused by this organism in these locations remains unknown [3]. However, some isolates of a bacterium typed as H. alvei from patients with diarrhoea in Bangladesh produced diarrhoea in rabbits by attaching and effacing (AE) lesions in the intestinal mucosa that are characteristic of the lesions produced by entero- pathogenic Escherichia coli [4]. Like enteropathogenic E. coli,theseH. alvei isolates possess a homologous patho- genicity island in the chromosome locus for enterocyte effacement (LEE), which is responsible for producing attaching and effacing lesions [5]. LEE encodes a type III secretory system [6]. Secretion of the virulence factors leads to effacement of the microvillus structure and reorganiza- tion of the actin cytoskeleton to form a pedestal-like structure, the attaching and effacing lesion [7]. AE lesion formation is critical in mediating diarrhoea production in the host, but its exact role in disease is not known. Recent results from conventional biochemical analyses, testing of susceptibility to cephalothin, lysis by a Hafnia-specific phage, and amplification of the outer membrane protein gene phoE with species-specific primers support the identi- fication of these isolates as 1313 ᭧ 2000 The Society for the Study of Evolution. All rights reserved. Evolution, 54(4), 2000, pp. 1313–1325 REPRODUCTIVE CHARACTER DISPLACEMENT AND SPECIATION IN PERIODICAL CICADAS, WITH DESCRIPTION OF A NEW SPECIES, 13-YEAR MAGICICADA NEOTREDECIM D AVID C. M ARSHALL 1,2 AND J OHN R. C OOLEY 2,3 Department of Biology and Museum of Zoology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, Michigan 48109-1079 1 Email: dmarshal@umich.edu Abstract. Acoustic mate-attracting signals of related sympatric, synchronic species are always distinguishable, but those of related allopatric species sometimes are not, thus suggesting that such signals may evolve to ‘‘reinforce’’ premating species isolation when similar species become sympatric. This hypothesis predicts divergences restricted to regions of sympatry in partially overlapping species, but such ‘‘reproductive character displacement’’ has rarely been confirmed. We report such a case in the acoustic signals of a previously unrecognized 13-year periodical cicada species, Magicicada neotredecim, described here as a new species (see Appendix). Where M. neotredecim overlaps M. tredecim in the central United States, the dominant male call pitch (frequency) of M. neotredecim increases from approximately 1.4 kHz to 1.7 kHz, whereas that of M. tredecim remains comparatively stable. The average preferences of female M. neotredecim for call pitch show a similar geographic pattern, changing with the call pitch of conspecific males. Magicicada neotredecim differs from 13-year M. tredecim in abdomen coloration, mitochondrial DNA, and call pitch, but is not consistently distinguishable from 17-year M. septendecim; thus, like other Magicicada species, M. neotredecim appears most closely related to a geographically adjacent counterpart with the alternative life cycle. Speciation in Magicicada may be facilitated by life-cycle changes that create temporal isolation, and reinforcement could play arole by fostering divergence in premating signals prior to speciation. We presenttwo theories ofMagicicada speciation by life-cycle evolution: ‘‘nurse-brood facilitation’’ and ‘‘life-cycle canalization.’’ Key words. Allochronic isolation, life-cycle evolution, Magicicada, reinforcement, reproductive character displace- ment, reproductive isolation, speciation. Received March 23, 1999. Accepted January 11, 2000. Periodical cicadas (Magicicada spp.) live underground as juveniles for either 13 or 17 years, after which they emerge for a brief adult life of approximately three weeks (Williams and Simon 1995). In northern and plains states, three mor- phologically and behaviorally distinct species coexist and emerge together once every 17 years (Fig. 1). These species are reproductively isolated in part by distinctive male acous- tic signals and female responses (Alexander and Moore 1958, 1962). In the Midwest and South, three similar 13-year spe- cies have been described. Each species appears most closely related to another with the alternative life cycle; some of these species pairs can be distinguished only by life-cycle length (Table 1). This pattern suggests that speciation in Mag- icicada may involve a combination of geographic isolation and life-cycle changes that create temporal isolation (Alex- ander and Moore 1962; Lloyd and Dybas 1966; Lloyd and White 1976). Speciation involving allochronic isolation has been proposed for other organisms (e.g., field crickets: Al- exander and Bigelow 1960; Alexander 1968; green lace- wings: Darwin and the Nature of Species David N. Stamos Darwin and the Nature of Species i SUNY series in Philosophy and Biology David Edward Shaner, editor Darwin and the Nature of Species David N. Stamos State University of New York Press Published by State University of New York Press, Albany ©2007 State University of New York All rights reserved Printed in the United States of America No part of this book may be used or reproduced in any manner whatsoever without written permission. No part of this book may be stored in a retrieval system or transmitted in any form or by any means including electronic, electrostatic, magnetic tape, mechanical, photocopying, recording, or otherwise without the prior permission in writing of the publisher. For information, address State University of New York Press, 194 Washington Avenue, Suite 305, Albany, NY 12210-2384 Production by Michael Haggett Marketing by Susan M. Petrie Library of Congress Cataloging-in-Publication Data Stamos, David N., 1957- Darwin and the nature of species / David N. Stamos. p. cm. – (SUNY series in philosophy and biology) Includes bibliographical references (p. ) and index. ISBN-13: 978-0-7914-6937-8 (hardcover : alk. paper) ISBN-10: 0-7914-6937-9 (hardcover : alk. paper ISBN-13: 978-0-7914-6938-5 (pbk. : alk paper) ISBN-10: 0-7914-6938-7 (pbk. : alk. paper) 1. Species–Philosophy. 2. Darwin, Charles, 1809-1882. I. Title. II. Series. QH83.S748 2007 578'.012–dc22 2005036225 10987654321 In memory of my mentor and friend the late Robert H. Haynes, who enjoyed to the last what he called “the opiate of Darwinism.” This page intentionally left blank. Contents  Preface ix Acknowledgments xix 1. A History of Nominalist Interpretation 1 2. Taxon, Category, and Laws of Nature 21 3. The Horizontal/Vertical Distinction and the Language Analogy 37 4. Common Descent and Natural Classification 65 5. Natural Selection and the Unity of Science 81 6. Not Sterility, Fertility, or Niches 107 7. The Varieties Problem 131 8. Darwin’s Strategy 153 9. Concept Change in Scientific Revolutions 187 10. Darwin and the New Historiography 207 Notes 231 References 249 Index 267 vii This page intentionally left blank. Preface  Looking back, I think it was more difficult to see what the problems were than to solve them. —Charles Darwin (letter to Charles Lyell, September 30, 1859) The year 1859 marks the beginning of an enormous earthquake, an earth- quake that shook the world and continues to shake it to this very day. The earthquake and the consequent tremors were not caused by the gradual shift and strain of conflicting ideas, but by a sudden impact, the [...]... spi-b525 The Formation of the Solar System This page intentionally left blank 2 9in x 6in ch01 FA1 August 30, 2007 10:17 spi-b525 The Formation of the Solar System 9in x 6in ch01 Chapter 1 Theories Come and Theories Go It’s all kinds of old defunct theories, all sorts of old defunct beliefs, and things like that It’s not that they actually live on in us; they are simply lodged there and we cannot get rid of. .. understand it The mathematical model of the bigbang is plain enough and many physicists and astronomers, including myself, can deal with that but I doubt that there are many people xv fm FA1 August 30, 2007 10:19 spi-b525 The Formation of the Solar System 9in x 6in The Formation of the Solar System on this Earth that really understand it My own test of whether or not I understand something is whether... like the Solar System has proved to be a very difficult exercise 6 FA1 August 30, 2007 10:17 spi-b525 The Formation of the Solar System 9in x 6in ch01 Theories Come and Theories Go 1.3 New Theories for Old The history of science is peppered with ideas that have held sway, that were eventually found to be flawed and were then replaced by some new ideas The lesson to be learnt from this is that no theory... Although by no stretch of the imagination could one envisage any practical outcome from the deflection of a beam of light passing the Sun, at least it was possible to do the experiment to show that the prediction was true There are other areas of science where there 5 FA1 August 30, 2007 10:17 spi-b525 The Formation of the Solar System 9in x 6in ch01 The Formation of the Solar System is limited opportunity... 30, 2007 10:19 spi-b525 The Formation of the Solar System 9in x 6in The Formation of the Solar System some of them were superficially attractive they all failed because they contravened some important scientific principle; it is a basic requirement of any theory that every aspect of it must be consistent with the science that we know If a theory explains many things in the Solar System but is in conflict... Hydrogen Bomb The Colliding Planets xi FA1 August 30, 2007 10:19 spi-b525 The Formation of the Solar System 9in x 6in fm The Formation of the Solar System 34.6 The Collision 34.7 Summary and Comments 244 246 Chapter 35 Behold the Wandering Moon 247 35.1 35.2 35.3 35.4 35.5 247 248 252 253 255 Orphans of the Storm A Lopsided Moon The Lopsided Moon — An Answer and a Question Collision to the Rescue A... struggling to find ways of just producing the Sun, planets and satellites, let alone all the other bodies of the Solar System Part of the problem has been that scientists have tended to concentrate on parts of the system rather than looking at it as a whole It is as though one was trying to understand the structure and workings of a car by studying just the wheels, the transmission system or the seats It is... is the length of the shortest sprint race in the Olympics For longer distances the kilometre (km), for example, one thousand metres is a better unit, i.e the distance from London to Edinburgh is 658 km Time has a variety of units, although for the scientist the basic unit is the second 9 FA1 August 30, 2007 10:17 spi-b525 The Formation of ... population or species In short, organisms must be able to reproduce with each other to pass new traits to offspring 2/14 Formation of New Species Speciation The biological definition of species, which... 3/14 Formation of New Species Biologists think of speciation events as the splitting of one ancestral species into two descendant species There is no reason why there might not be more than two species. .. the formation of a new lake A storm causes several large trees to fall down 12/14 Formation of New Species A mutation causes a new trait to develop An injury causes an organism to seek out a new