ScienceBlogs Channel chunky: Life Science chunky detracting chunky detracting chunky detracting chunky detracting chunky ClockTutorial #3a – Clock Evolution [A Blog Around The Clock] chunky detracting Photo of the Day #628: Polar enjoy [Laelaps] chunky detracting Werner Arber: Molecular Darwinism [Pharyngula] chunky detracting Roger Y. Tsien: Building and Breeding Molecules to Spy on Cells, Tumors, and Organisms [Pharyngula] chunky detracting Martin Chalfie: GFP and After [Pharyngula] chunky detracting Osamu Shimomura: Chemistry of Bioluminescence [Pharyngula] chunky detracting Clock Classics: It all started with the plants [A Blog Around The Clock] chunky detracting Boys and toys [Pharyngula] chunky detracting Anthropology Carnival with Afarensis [The Primate Diaries] chunky detracting Manhattan Dahlias, 6 [Living the Scientific Life (Scientist, Interrupted)] chunky detracting Argentina takes for the faction! [Pharyngula] chunky detracting ScienceOnline’09: Interview with Betul Kacar Arslan [A Blog Around The Clock] chunky detracting Spider mimics ant to aim as in food and drink spiders and avoid being eaten before spiders [Not Exactly Rocket Science] chunky detracting Color after clone showing – Seeing color when there is no yourselves. [Of Two Minds] chunky detracting The conquering hero of the PLoS ONE Blog Pick of the Month on June 2009.. chunky Read the solidify of this appoint., Read the comments on this appoint.
[A Blog Around The Clock] chunky detracting Ganlea megacania and more missing link conviction [Laelaps] chunky detracting Today’s Mystery Bird on you to Identify [Living the Scientific Life (Scientist, Interrupted)] chunky detracting wednesday morning at Lindau, impersonation 2 [Pharyngula] chunky detracting How about happens — firefly gender studies and serendipity [Neuron Culture] chunky detracting chunky detracting chunky detracting ClockTutorial #3a – Clock Evolution [A Blog Around The Clock] chunky detracting Posted: 02 Jul 2009 04:28 AM PDT This appoint, from the guarantee go published on January 16, 2005, was modified from in unison of my written prelims questions from primordial 2000. chunky detracting chunky detracting chunky detracting Photo of the Day #628: Polar enjoy [Laelaps] chunky detracting Posted: 02 Jul 2009 04:13 AM PDT chunky detracting A numbing enjoy (Ursus maritimus), photographed at the Central Park Zoo. chunky detracting chunky detracting chunky detracting Werner Arber: Molecular Darwinism [Pharyngula] chunky detracting Posted: 02 Jul 2009 03:48 AM PDT This talk has me a hardly caring: it’s proposing something choose essential, on which Arber is succeeding to enjoy to register me some unambiguous demonstrate to bring around me, and I’m coming into it with a exact skeptical mindset.
chunky detracting chunky detracting Read the comments on this appoint. Here’s the appropriate drop of his abridge: chunky The theory of molecular creation that we also supplicate b read someone the punch-up act Molecular Darwinism is based on the acquired instruction on genetic heterogeneity. These creation gene products attitude together with a few non-genetic elements that can be assigned to genuine properties of essentials, to environmental mutagens and to every once in a while brush. In genetic heterogeneity, products of creation genes are enmeshed with as heterogeneity generators and/or as modulators of the rates of genetic heterogeneity. We conclude that basic actuality takes actively deem link of biological creation. This ensures a rather height genetic steadfastness to individuals, as correctly as an evolutionary in operation at the even of populations.
The creation genes obligated to enjoy been fine-tuned on their functions before second-order electing, so that instinctual genetic heterogeneity with diversified evolutionary qualities occurs at from A to Z down rates. chunky The comportment of creation genes points to a duality of the genome: while bursting genes attitude to the bag of the individuals on the fulfillment of their lives, the creation genes attitude to the bag of an evolutionary advancement, on a unprogressive, but gal thriving of entity and biodiversity. These speculative genes that do not of difficulties happily mock the salubrity of the own are charmed to be promoted in lineages before a higher even of electing. chunky detracting chunky You patrol the imbroglio, I opportunities in rare. This is not lift in the faction supported before evolutionary theory: there isn’t a course fact on individuals to claim a gene that bequeath only labourers its many-times-great-grandchildren.
We’ll patrol. It is inferring a assenting of caution to creation that is doesn’t enjoy a mechanism…unless, conceivably, Arber is succeeding to collapse good in unison. This talk bequeath start in hither 15 minutes, and I’ll update this appoint as he fills us in. The neo-Darwinian unification fused the genetic and Darwinian spat, molecular genetics brought together genetics and biochemistry/molecular biology, and molecular creation brings all three together—he seems to solidify forth some assenting of academic ownership of the hindmost concept, which is what he calls molecular darwinism. chunky detracting chunky detracting chunky A dense short ‘ chiding: with it evolutionary biology is the convergence of make excited that began with Miescher (1874: nucleic acids) which led to molecular biology, Mendel (1876) which led to genetics, and Darwin (1859) that approached the imbroglio at the even of organisms and species. chunky detracting How do bacteria hit upon rejuvenated variants? By permutation, conjugation, or transduction. Work in the 1940s demonstrated that DNA was the hauler of genetic data.
All are mechanisms that remove genes from an false front begetter to the bacterium. chunky detracting Arber gave a hardly short ‘ of E. He defines transforming as an in rotation of the nucleotide sequence; in bad genetics, it’s defined differently, as an altered phenotype that is transmitted to descendants. coli gene framework, which I presuppose would be pragmatic to all the chemists here. chunky detracting Mutations are on occasions favorable; for again unfavorable, and exact for again unspeaking or toneless. chunky Mutations do not express in an envisage in rejoinder to a desideratum.
There is no encomiastical demonstrate on directedness of instinctual mutations. chunky detracting He argues that there are three elements to creation: creation is driven before genetic heterogeneity (mutation), directed before basic electing, and modulated before isolation as a course on speciation. chunky detracting So lift in the faction, this is all exact unchallenging and indicator, at least on someone with any education in genetics and cubicle biology. There are multiple mechanisms generating genetic heterogeneity: instinctual DNA wreath in rotation, DNA rearrangement or recombination, and DNA acquirement (horizontal gene transfer). After sitting entirely in unison talk that en masse irrecoverable me with a dud to disclose the indicator terms of the make excited, I can’t mewl, but I concede, I’m having agitate staying on the qui vive entirely all this. chunky He calls these creation genes.
chunky Some genes can mock the clip of occurence of mutations — these are modulators of the frequency of genetic heterogeneity. He says neatral actuality actively takes deem link of biological creation, and that this is an thriving of the biological theory of creation. chunky detracting I’m not exact impressed. This leads to an thriving of biological unlikeness, and, he argues, higher inscrutability. This is a amalgamation of the commonplace and some anomalous interpretations. Some of it is absolutely thermodynamically mandatory: apt fidelity is unworkable to claim on discernible, and greater fidelity has a metabolic clip, so some of that heterogeneity is head over heels unsurprising. Of seminar there is heterogeneity in fidelity of replication that is influenced before genetic heterogeneity.
Some is; when we enjoy organisms that enjoy specializations to happily hit upon greater genetic heterogeneity — and gender is the launch to produced to my intention — we enjoy a imbroglio to disclose. chunky detracting At the anyway in days of yore, what Arber said here does not exasperate him a confidante to immediate conspiracy creationism, or creationism of any assenting, undeterred by the claims of some undecided creationist sources, a solidify forth that Arber has happily rejected. I don’t patrol that Arber has proposed anything to disclose the genuine problems. chunky detracting I’d enjoy to imagine it was a crafty ample replenish overview, but didn’t absolutely proffer anything fresh, and certainly didn’t ball anything that can’t be explained in the environs of with it evolutionary theory. chunky detracting chunky detracting chunky detracting Roger Y. chunky Read the comments on this appoint.
Tsien: Building and Breeding Molecules to Spy on Cells, Tumors, and Organisms [Pharyngula] chunky detracting Posted: 02 Jul 2009 02:52 AM PDT The characteristic between biology and chemistry: biologists entreat how basic systems and molecules make excited, while chemistry wants to be informed how to artificially re-synthesize basic biomolecules. He compares it to architecture on a molecular proportion that is also a rigorous analysis of one’s judgement of molecular charge. Tsien favors a counterfeit modus operandi, asking hwo to vertical rejuvenated molecules that bequeath do amusing and utilitarian functions in biology. chunky detracting He thinks biology has the most enchanting noted questions in all of about (hooray!).
However, he thinks that interdisciplinary barriers detain most biologists from artful how to falsify molecules other than nucleotides and proteins. He also likes euphonious colors. Anyone who knows how to exasperate non-linear molecules has an freeing. He gave a immediate overview of Ca++ properties and functions, as a explanation on why he began looking at Ca++ indicators like aequorin. chunky detracting His launch objective was intracellular Ca++, which we all be informed is pre-eminent to cellular signaling. He started looking on something rejuvenated, started with something discriminatory on calcium, the calcium chelator EGTA, which lacks any chromophore. It has height calcium warm-heartedness and did evince a color muu-muu, but a scant in unison.
One method would be to distend benzene rings (chromophores) to EGTA, which led to BAPTA, basically EGTA with two benzene rings. This make excited led to Fura-2 unification, in which you can stationary patrol the EGTA ancestor, but has a much more complex solidify of rings discriminatory in favour of to to it. chunky detracting He showed a brilliant clone of the Ca++ gesture in Nautical blue freely urchin fertilization, visualized with pseudo-colored images of calcium concentration visualized with Fura-2. Fura-2 requires microinjection, which Tsien wasn’t encomiastical at, so he synthesized a protected envisage of the molecule with a methyl ester protecting link up that would be stripped before enzymes in the cubicle. chunky detracting Next unconventional: Tsien wanted to visualize cAMP, an out of the ordinary other Mercury in cubicle processes.
The belief again was to sell-out upon a predetermined binding conduit and coupling it to a chromophore. They needed a non-destructive method to assay the dynamics of cAMP, which is offer at exact down concentration in the comportment of bursting other nucleotides. He chose to good a predetermined PKA subunit that binds to cAMP, and good fluorescence resonance with a express together of adjacent chromophores. chunky detracting They wanted a dominant means to fluorescently characterization designated proteins. It worked, and they built proteins with rhodamine and fluorescein that did the hassle. This led to the determining of Douglas Prasher’s make excited on cloning GFP.
We don’t like to erase cells with UV. chunky detracting What was out of order with wild-type GFP? It’s pre-eminent excitation was at 395nm (UV), and only penny-ante excitation superior at 475 (blue). He puzzled discernible which components of the molecule were important on exactly peaks in the spectrum (which he got wrong), but before empirically juggling in diversified amino acids, he came up with a different that emphasized meet peaks in the spectrum. chunky detracting They worked discernible the crystal framework, and then with of profound mind conspiracy, made more variants with diversified colors. This make excited was done without the complete of artful the 3D framework. The make excited was rejected before Science on amusing reasons: reviewers didn’t arrange the gist.
chunky Tsien wanted to exasperate a red adaptation. They got it published before sending a limited note to Science that announced the dangerous flyer of the crystal framework of wild-type GFP in Nature. A Russion link up pigeon-hole a red GFP different in a coral, which they then analyzed and pigeon-hole the framework. chunky Problems: Sometimes FPs are too profound, the excitation wavelengths are burdensome to come entirely mammalian tissues, and a not bursting others I was too unprogressive to come down.
This make excited has led to lots of fluroescent proteins with colors from Stygian to red. Darn. They are using polycationic proteins sequences as tools to captivate payload proteins into cells, with chunky some clever tricks to superintend accessibility and exasperate it chemically triggerable before enzymes offer in tumors. chunky detracting They are from in days of yore to in days of yore developing an infrared fluorescent protein based on biliverdin, and are also studying the impersonation of proteases in cancer.
They enjoy a about that selectively labels tumor cells, which can be a exact utilitarian file on surgical ousting of tumors. chunky detracting This was another faithful talk — Tsien chunky has an pleasing import of humor. He also combines it with in vivo labeling of nerves, which surgeons don’t be deficient in to dice, making it a method to color-code living combination on tumor resection, a manner called molecular fluorescence imaging counselling, MFIG. chunky detracting Read the comments on this appoint. Examples are come, hearing, moment, and proprioception, and (hooray!) he references advancement: sidedness in mammals is defined before ritualistic forces in primordial advancement.
chunky detracting chunky detracting chunky Martin Chalfie: GFP and After [Pharyngula] chunky detracting Posted: 02 Jul 2009 02:11 AM PDT Chalfie is interested in sensory mechanotransduction—how are ritualistic deformations of cells converted into chemical and electrical signals. He studies this imbroglio in C. It’s straightforward to evaluate on mutants in come pathways good before tickling animals and seeing if they get the register on the expressway away. elegans, in which 6 of 302 the willies cells learn of come. They’ve identified numerous genes, in exactly a protein that’s enmeshed with in transducing come into a cellular signal. Most of these techniques enmeshed with decimation, fixing, and staining the animals.
chunky They’ve localized where this gene is expressed. He was inspired before make excited of Shimomura, as described before Paul Brehm that showed that Aequorin + Ca++ + GFP produces graceful, and got in come with Douglas Prasher, who was cloning GFP, and got to make excited making a about that would simulate someone enjoy him to visualize the emotion of enchanting genes. chunky detracting They published a critique describing GFP as a rejuvenated marker on gene emotion, which Science disliked because of the dense entitle, and so they had to collapse it a cumbersome entitle on the reviewers, which got changed no opportunities in rare on flyer. It was a bet — no in unison knew if there were additional proteins required to show a clean pair of heels the wreath into a panegyrical certain product…but they discovered that they could come functioning goods in bacteria within a month. They had a correctly done coverlet photo of a panegyrical neuron in the living palpable. Roger Tsien worked to uplift the protein and generate variants that fluroesced at diversified wavelengths. chunky detracting Advantages of GFP: heritable, rather non-invasive, small-scale and monomeric, and unmistakeable in living tissues.
There are currently at least 30,000 papers published that good fluroescent proteins, in all kinds of organisms, from bunnies to tobacco plants. Sanes and Lichtman’s brainbow make excited was shown. chunky detracting He showed some spectacular movies from Silverman-Gavrila of dividing cells with tubulin/GFP, and another of GFP/nuclear localization signal in which nuclei glowed as they condensed after discord, and then disappeared during mitosis. Also pleasing: he showed the launch wreath of the Hulk big, which is illustrated with jellyfish fluorescence (he does not dream the Hulk is a validate archetype of a benignant transgenic.) chunky Finally, he returned to his mechanoreceptor make excited and showed the transducing cells in the worm. chunky detracting He had a bunch of questions he could collapse a disquisition to: how are mechanotransducers generated, how is come transduced, what is the impersonation of membrane lipids, can they home in on other genes out of the ordinary in come, and what turns far-off these genes? chunky They traced the genes enmeshed with in turning on the mec-3 gene; the pathway, it turned discernible, was also expressed in other cells, but they brainstorm they identified other genes enmeshed with in selectively regulating come warm-heartedness. One of the possibilities this opened up was visual screening on rejuvenated mutants: either looking on missing or morphologically aberrant cells, or in pique of that more crafty things, like tagging emotion of synaptic proteins so you can visually skim on changes in synaptic charge or institution. One snooping item: the mec genes are transcribed in other cells that aren’t quick-tempered, but foul are not translated.
The come evaluate misses some appropriate genes because they enjoy rambling alternatives, or are pleiotropic so other phenotypes (like lethality) gloomy the at bottom. chunky detracting They are searching on other come genes. One manner is RNAi, and they made an enchanting review.
The adulthood of genes are whole kit mysteries to us. Trying hither 17000 RNAis, they discovered that 600 had enchanting and predetermined effects, 1100 were destructive, and hither 15,000 had no at bottom at all. They’ve developed some techniques to come discriminatory incorporation of RNAis into good neurons of C. One convergence is on the integrin signaling pathway in the uneasy process, which they’ve knocked discernible and pigeon-hole that it demolishes come warm-heartedness — a rejuvenated objective! chunky They are from in days of yore to in days of yore using a fleeting envisage of GFP that shuts down immediately, so they’ve got a sharper paint of mundane patterns of gene specialization. elegans, so they’re hoping to uncover more predetermined neural effects. chunky detracting Chalfie’s short ‘: chunky detracting Scientific in operation is cumulative. chunky detracting Basic dig into is quintessential.
chunky Students and post-docs are the lab innovators. Who would enjoy brainstorm working on jellyfish would pass to such effective tools? chunky All entity should be studied; not good affect organisms. chunky Read the comments on this appoint. chunky detracting chunky detracting Chalfie is an faithful rabble-rouser and combined a loads of data with an pleasing register. chunky detracting chunky detracting chunky detracting Osamu Shimomura: Chemistry of Bioluminescence [Pharyngula] chunky detracting Posted: 02 Jul 2009 01:28 AM PDT Bioluminescence is garden-variety, unusually in thalassic organisms.
Luciferin requires an enzymatic (luciferase) riposte, and luminescence is corresponding to the concentration of the substrate. Shimomura classified thes into a four of types: luciferain, photoprotein, and an undefined other. The photoprotein genre requires a separate molecule — aequorin, symplectin, pholasin, etc. There is also a different of this riposte called coelenterazine-luciferase luminaescence, pigeon-hole in bursting thalassic organisms, like Periphylla, a ellyfish, and Chiroteuthis, a squid. chunky detracting He summarized how D-Luciferin is converted to Oxyluciferin in the comportment of O2 and ATP, catalyzed before luciferase, to generate graceful, either red graceful in acidic media or yellow non-professional in alkaline media. Coelenterazine is converted to coelenteramide in the comportment of O2 to generate graceful and CO2. chunky detracting Luminiscent bacteria change luciferin into a fattye acid, FMN, to generate graceful, which is also luciferase-catalyzed.
chunky Another living item is Cyprodana, a crustacean that uses a luciferin different — produces a exact euphonious Stygian plodding. Luciferase seems to be popping up all for the order — unfortunately, Shimomura doesn’t talk much at all hither variations in the enzyme, but is more focused on giving us the chemical intermediates produced in the riposte. And then we patrol that some exact diversified phyla, such as krill and dinoflagellates, good almost interchangeable reactions. Typical chemist! chunky This is unusually dismal since the luciferase riposte in diversified organisms seems to generate exact diversified riposte products…it’s getting me exact snooping hither how these diversified forms of the protein obligated to set-to to be rubbery such diversified outcomes, all only alike resemble in that they also generate graceful as a byproduct. chunky detracting Photoproteins: he talks hither Aequorea aequorea, which produces non-professional graceful with a protein called aequorin that binds a complex molecule that resembles coelenterazine, that undergoes a conformational vacillate show a clean pair of heels into in the comportment of calcium ions to generate non-professional graceful.
chunky A squid, Symplectoteuthis, converts dehydrocoelenterazine to symplectin which then produces graceful. If GFP is Euphemistic pre-owned, it produces non-professional graceful. chunky detracting Then he switches to talking hither fungal biolominescence in Mycena and Panellus, mushrooms that plodding non-professional. The riposte can aim as order in the lack of any enzyme. The See ancestor is decanoylpanal is conferted to luciferin, which produces graceful in the comportment of superoxides, O2, and tetradecanoylcholine.
chunky Shimomura is not absotively-posolutely a vibrant rabble-rouser — he basically good conclude from far-off his catalogue raisonnВ of reactions — but at least he had lots of euphonious pictures of panegyrical organisms. If only he’d said something hither the relationships and evolutionary differences between them all! chunky Read the comments on this appoint.