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Thread: Alga Of The Year 2014

  1. #1
    Daihonmei MikeM's Avatar
    Join Date
    Dec 2003
    Orlando, Florida

    Alga Of The Year 2014

    This is just too much fun not to share with folks. It may not have much to do with koi directly, but we do spend a lot of time talking about greenwater algae without knowing much about them. And, in any event, if it makes you smile, it's a good thing.

    Phycologists of the Botanical Society of Germany have selected Chlamydomonas reinhardtii as Alga Of The Year for 2014. That's right, there is an alga (singular of algae) being especially honored this year, at least by German phycologists (scientists who study algae).

    So, what is so great about C. reinhardtii? Well, it is a unicellular green alga that can be found throughout the world. There are undoubtedly some in the koi ponds of virtually everyone reading this post. It has become much appreciated by algae researchers and the German botanical society praise it for crossing into the field of medicine, with medical scientists finding it to be an ideal organism for studying a variety of biological questions. (Just how this little alga is proving helpful in regard to the study of several human diseases is quite unclear to me, but it is the subject used in a lot of studies. I've been reading a good deal about unicellular algae lately, but I've shied away from the medical literature.) The German phycologists particularly laud C. reinhardtii for having "a specific diurnal behavior, which is triggered by an endogenous clock". (I believe they are referring to its ability to grow using photosynthesis during the day, and using chemical energy sources to continue growing during the night in certain conditions.) Its intriguing features include its method of light perception using a primitive visual system and the transfer of the information to motile cilia, allowing it to move toward a desired light intensity. And, this tiny alga can protect itself from bursting by discharging excessive water. Plus, if you like microscope slide photos, it is a pretty green dot. …If you like green dots.

    So, you see, this little alga has within its single cell the beginnings of what you might think of as an eye, a kidney and locomotion. Quite the talented cell.

    I've said before that the koi addiction can lead one down bizarre paths, and I certainly go down my full share. I wonder what causes a whole group of people to so devote themselves to the study of algae that they seriously pursue selection of an Alga Of The Year? Humans are truly strange creatures.


    If you are interested in learning more about this alga, Wikipedia is a decent starting point:

    Chlamydomonas reinhardtii is a single-cell green alga about 10 micrometres in diameter that swims with two flagella. It has a cell wall made of hydroxyproline-rich glycoproteins, a large cup-shaped chloroplast, a large pyrenoid, and an "eyespot" that senses light.

    Although widely distributed worldwide in soil and fresh water, C. reinhardtii is used primarily as a model organism in biology in a wide range of subfields. When illuminated, C. reinhardtii can grow in media lacking organic carbon and chemical energy sources, and can also grow in the dark when supplied with these. C. reinhardtii is also of interest in the biopharmaceuticals field and the biofuel field, as a source of hydrogen.

    The C. reinhardtii wild-type laboratory strain c137 (mt+) originates from an isolate made near Amherst, Massachusetts, in 1945 by Gilbert M. Smith.[1][2]

    The species has been spelled several different ways because of different transliterations of the name from Russian: reinhardi, reinhardii, and reinhardtii all refer to the same species, C. reinhardtii Dangeard.[3]

    Model organism[edit]
    Cross section of a Chlamydomonas reinhardtii algae cell, a 3D representationChlamydomonas is used as a model organism for research on fundamental questions in cell and molecular biology such as:

    How do cells move?
    How do cells respond to light?
    How do cells recognize one another?
    How do cells generate regular, repeatable flagellar waveforms?
    How do cells regulate their proteome to control flagellar length?
    How do cells respond to changes in mineral nutrition? (nitrogen, sulfur, etc.)
    There are many known mutants of C. reinhardtii. These mutants are useful tools for studying a variety of biological processes, including flagellar motility, photosynthesis, and protein synthesis. Since Chlamydomonas species are normally haploid, the effects of mutations are seen immediately without further crosses.

    In 2007, the complete nuclear genome sequence of C. reinhardtii was published.[4]

    Channelrhodopsin-1 and Channelrhodopsin-2, proteins that function as light-gated cation channels, were originally isolated from C. reinhardtii.[5][6] These proteins and others like them are increasingly widely used in the field of optogenetics.[citation needed]

    Reproduction[edit]Vegetative cells of the reinhardtii species are haploid with 17 small chromosomes. Under nitrogen starvation, haploid gametes develop. There are two mating types, identical in appearance and known as mt(+) and mt(-), which can fuse to form a diploid zygote. The zygote is not flagellated, and it serves as a dormant form of the species in the soil. In the light, the zygote undergoes meiosis and releases four flagellated haploid cells that resume the vegetative lifecycle.

    Under ideal growth conditions, cells may sometimes undergo two or three rounds of mitosis before the daughter cells are released from the old cell wall into the medium. Thus, a single growth step may result in 4 or 8 daughter cells per mother cell.

    The cell cycle of this unicellular green algae can be synchronized by alternating periods of light and dark. The growth phase is dependent on light, whereas, after a point designated as the transition or commitment point, processes are light-independent.[7]

    Genetics[edit]The attractiveness of the alga as a model organism has recently increased with the release of several genomic resources to the public domain. The Chlre3 draft of the Chlamydomonas nuclear genome sequence prepared by Joint Genome Institute of the U.S. Dept of Energy comprises 1557 scaffolds totaling 120 Mb. Roughly half of the genome is contained in 24 scaffolds all at least 1.6 Mb in length. The current assembly of the nuclear genome is available online.[8]

    The ~15.8 Kb mitochondrial genome (database accession: NC_ 001638) is available online at the NCBI database.[9] The complete >200 Kb chloroplast genome is available online.[10]

    In addition to genomic sequence data, there is a large supply of expression sequence data available as cDNA libraries and expressed sequence tags (ESTs). Seven cDNA libraries are available online.[11] A BAC library can be purchased from the Clemson University Genomics Institute.[12] There are also two databases of >50 000[13] and >160 000[14] ESTs available online.

    Evolution[edit]Chlamydomonas has been used to study different aspects of evolutionary biology and ecology. It is an organism of choice for many selection experiments because (1) it has a short generation time, (2) it is both a heterotroph and a facultative autotroph, (3) it can reproduce both sexually and asexually, and (4) there is a wealth of genetic information already available.

    Some examples (nonexhaustive) of evolutionary work done with Chlamydomonas include the evolution of sexual reproduction,[15] the fitness effect of mutations,[16] and the effect of adaptation to different levels of CO2.[17]

    DNA transformation techniques[edit]Gene transformation occurs mainly by homologous recombination in the chloroplast and heterologous recombination in the nucleus. The C. reinhardtii chloroplast genome can be transformed using microprojectile particle bombardment or glass bead agitation, however this last method is far less efficient. The nuclear genome has been transformed with both glass bead agitation and electroporation. The biolistic procedure appears to be the most efficient way of introducing DNA into the chloroplast genome. This is probably because the chloroplast occupies over half of the volume of the cell providing the microprojectile with a large target. Electroporation has been shown to be the most efficient way of introducing DNA into the nuclear genome with maximum transformation frequencies two orders of magnitude higher than obtained using glass bead method.[citation needed]

    Production of biopharmaceuticals[edit]Genetically engineered Chlamydomonas reinhardtii has been used to produce a mammalian serum amyloid protein, a human antibody protein, human Vascular endothelial growth factor, a potential therapeutic Human Papillomavirus 16 vaccine,[18] a potential malaria vaccine,[19] and a complex designer drug that could be used to treat cancer.[20]

    Clean source of hydrogen production[edit]Main article: Biological hydrogen production (Algae)
    In 1939, the German researcher Hans Gaffron (1902–1979), who was at that time attached to the University of Chicago, discovered the hydrogen metabolism of unicellular green algae. Chlamydomonas reinhardtii and some other green algae can, under specified circumstances, stop producing oxygen and convert instead to the production of hydrogen. This reaction by hydrogenase, an enzyme active only in the absence of oxygen, is short-lived. Over the next thirty years, Gaffron and his team worked out the basic mechanics of this photosynthetic hydrogen production by algae.[21]

    To increase the production of hydrogen, several tracks are being followed by the researchers.

    The first track is decoupling hydrogenase from photosynthesis. This way, oxygen accumulation can no longer inhibit the production of hydrogen. And, if one goes one step further by changing the structure of the enzyme hydrogenase, it becomes possible to render hydrogenase insensitive to oxygen. This makes a continuous production of hydrogen possible. In this case, the flux of electrons needed for this production no longer comes from the production of sugars but is drawn from the breakdown of its own stock of starch.[22]
    A second track is to interrupt temporarily, through genetic manipulation of hydrogenase, the photosynthesis process. This inhibits oxygen's reaching a level where it is able to stop the production of hydrogen.[23]
    The third track, mainly investigated by researchers in the 1950s, is chemical or mechanical methods of removal of O2 produced by the photosynthetic activity of the algal cells. These have included the addition of O2 scavengers, the use of added reductants, and purging the cultures with inert gases.[24] However, these methods are not inherently scalable, and may not be applicable to applied systems. New research has appeared on the subject of removing oxygen from algae cultures, and may eliminate scaling problems.
    A fourth track has been investigated, namely using copper salts to decouple hydrogenase action from oxygen production.[25]

  2. #2
    Join Date
    Jan 2014
    Dear Mike,

    LOL , You have me now obsessing about not having age in my setup


  3. #3
    Sansai almostgeorgia's Avatar
    Join Date
    Aug 2008
    Amelia Island, FL
    Mike, you appear to have raised your interest (and deep knowledge) of algae past the 'savant' level and into outright obsession! Alga of the year. What next?

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