The sex-inducer of the spherical green alga Volvox carteri is one of the most potent biological effector molecules known: it is released into the medium by sexual males and triggers the switch to the sexual cleavage program in the reproductive cells of vegetatively grown males and females even at concentrations as low as 10 (-16) M. In an adult Volvox alga, all cells are embedded in an extensive extracellular matrix (ECM), which constitutes >99% of the volume of the spheroid. There exist no cytoplasmic connections between the cells in an adult alga, so any signal transduction between different cells or from the organisms environment to a reproductive cell must involve the ECM. Recently, a small cysteine-rich extracellular protein, VCRP, was identified in Volvox and shown to be quickly synthesized by somatic cells in response to the sex-inducer. Due to its characteristics, VCRP was speculated to be an extracellular second messenger from somatic cells to reproductive cells. Here a related ...

The Volvox carteri genome was first sequenced in 2010.[6] It had generated interest as a model system to examine the evolution of multicellularity and genomic complexity associated with such a phenomenon. The number of chromosomes that composes the nuclear genome of V. carteri is unestablished; some sources indicate the identification of up to 19 distinct linkage groups, while others find just 14.[5][6] A number of genome characteristics have been defined, however. The nuclear genome is 138 Mbp long and 18% coding, with a GC content of 56%.[5] A number of papers investigating the evolution of complexity and multicellularity compare the V. carteri genome to a related member of the Volvocine algae family, Chlamydomonas reinhardtii. Relative to the other species in the family, these two organisms are as far apart evolutionarily as possible; C. reinhardtii is simpler and unicellular. Though sequencing both of their genomes has given us insights into their evolutionary history, interest in an ...

The Volvox carteri genome was first sequenced in 2010.[6] It had generated interest as a model system to examine the evolution of multicellularity and genomic complexity associated with such a phenomenon. The number of chromosomes that composes the nuclear genome of V. carteri is unestablished; some sources indicate the identification of up to 19 distinct linkage groups, while others find just 14.[5][6] A number of genome characteristics have been defined, however. The nuclear genome is 138 Mbp long and 18% coding, with a GC content of 56%.[5] A number of papers investigating the evolution of complexity and multicellularity compare the V. carteri genome to a related member of the Volvocine algae family, Chlamydomonas reinhardtii. Relative to the other species in the family, these two organisms are as far apart evolutionarily as possible; C. reinhardtii is simpler and unicellular. Though sequencing both of their genomes has given us insights into their evolutionary history, interest in an ...

The extracellular matrix (ECM) of Volvox is modified during development or in response to external stimuli, like the sex-inducing pheromone. It has recently been demonstrated that a number of genes triggered by the sex-inducing pheromone are also inducible by wounding. By differential screening of a cDNA library, a novel gene was identified that is transcribed in response to the pheromone. Its gene product was characterized as an ECM glycoprotein with a striking feature: it exhibits a hydroxyproline content of 68% and therefore is an extreme member of the family of hydroxyproline-rich glycoproteins (HRGPs). HRGPs are known as constituents of higher plant ECMs and seem to function as structural barriers in defense responses. The Volvox HRGP is also found to be inducible by wounding. This indicates that the wound response scenarios of higher plants and multicellular green algae may be evolutionary related ...

Figure 2 from van Gestel and Tarnita, 2017. Relationship between life stages in hypothesized life cycles of solitary ancestors and group formation in derived group life cycles. (Upper) Simplified depiction of hypothesized ancestral solitary life cycles of the green alga Volvox carteri, the cellular slime mold Dictyostelium discoideum, and the wasp Polistes metricus. Life cycles here consist of a life stage expressed under good conditions (black) and a life stage expressed under adverse conditions (green). For the latter life stage, we show an environmental signal that might trigger it and some phenotypic consequences. (Lower) Simplified depiction of group life cycles of: V. carteri, D. discoideum, and P. metricus. Developmental program underlying life stages in solitary ancestor is co-opted for group formation (shown in green): differentiation of somatic cells (V. carteri), fruiting body formation (D. discoideum), and appearance of foundress phenotype (P. metricus). ...

TY - JOUR. T1 - Planarian D-amino acid oxidase is involved in ovarian development during sexual induction. AU - Maezawa, Takanobu. AU - Tanaka, Hiroyuki. AU - Nakagawa, Haruka. AU - Ono, Mizuki. AU - Aoki, Manabu. AU - Matsumoto, Midori. AU - Ishida, Tetsuo. AU - Horiike, Kihachiro. AU - Kobayashi, Kazuya. N1 - Funding Information: We are grateful to Dr. P. A. Newmark (University of Illinois) for generously providing the L4440 vector used in our RNAi analysis, and Dr. Yuni Nakauchi and Mr. Ryo Sasaki (Yamagata University) for their invaluable assistance collecting B. brunnea. We also thank the members of our laboratory for their valuable comments. This work was supported in part by a Grant-in-Aid for Scientific Research in Innovative Areas (Regulatory Mechanism of Gamete Stem Cells; K.K., # 20116007 ), a Grant-in-Aid for Scientific Research (B) (K.K., # 22370026 ), a Grant-in-Aid for Scientific Research (C) (T.M., # 22603010 ), a Grant-in-Aid for Scientific Research (C) (H.T., #24590351), The ...

The 5th International Volvox Conference brought together international scientists working on volvocine algae together at the University of Tokyo to expand and strengthen the Volvocales research community.

Filamentous bacteria are the oldest and simplest known multicellular life forms. By using computer simulations and experiments that address cell division in a filamentous context, we investigate some of the ecological factors that can lead to the emergence of a multicellular life cycle in filamentous life forms. The model predicts that if cell division and death rates are dependent on the density of cells in a population, a predictable cycle between short and long filament lengths is produced. During exponential growth, there will be a predominance of multicellular filaments, while at carrying capacity, the population converges to a predominance of short filaments and single cells. Model predictions are experimentally tested and confirmed in cultures of heterotrophic and phototrophic bacterial species. Furthermore, by developing a formulation of generation time in bacterial populations, it is shown that changes in generation time can alter length distributions. The theory predicts that given the same

Cheats arise in the authors experimental populations and bring about collapse of the mats. The mats fail when cheats prosper: cheats obtain an abundance of oxygen, but contribute no glue to keep the mat from disintegrating - the mats eventually break and fall to the bottom where they are starved of oxygen.. Paul Rainey, who led the study at the New Zealand Institute for Advanced Study and the Max Planck Institute for Evolutionary Biology, explains: Simple cooperating groups - like the mats that interest us - stand as one possible origin of multicellular life, but no sooner do the mats arise, than they fail: the same process that ensures their success - natural selection - , ensures their demise.. But even more problematic is that groups, once extant, must have some means of reproducing themselves, else they are of little evolutionary consequence.. Pondering this problem led Rainey to an ingenious solution. What if cheats could act as seeds - a germ line - for the next set of mats: while ...

View Notes - bild2_3 from BILD 2 at UCSD. BILD 2: Multicellular Life LECTURE #3 [Website: http:/www.biology.ucsd.edu/classes/bild2.WI11.1] Instructor: Darwin K. Berg [email protected] Figure 48-7

Unit 9.2: The Evolution of Multicellular Life Lesson Objectives Describe important events of the late Precambrian. Give an overview of evolution during the Paleozoic Era. Explain why the Mesozoic Era is

Volvox colony. Light micrograph of a colony of the freshwater green alga Volvox sp. The colony is a hollow sphere made up from thousands of cells connected by cytoplasmic threads and arranged in a single layer. Each cell has two flagella, which point outwards, and are used for locomotion. The green spheres within the colony are daughter colonies, which are produced asexually. - Stock Image C010/5437

View Notes - L19 2009 Multicellular signalling from BIO G 1101 at Cornell. MULTICELLULARITY: CELL SIGNALING Lecture 19 9 October 2009 Multicellularity: Cell diversification acellular slime molds

The evolutionary path from unicellular life to multicellularity is varied, but all lead to complex organisms. In the beginning there were single cells. Today, many millions of years later, most plants, animals, fungi, and algae are composed of multiple cells that work collaboratively as a single being. Despite the various ways these organisms achieved multicellularity, their conglomeration of cells operate cooperatively to consume energy, survive, and reproduce. But how did multicellularity evolve? Did it evolve once or multiple times? How did cells make the transition from life as a solo cell to associating and cooperating with other cells such that they work as a single, cohesive unit?. Karl Niklas (Cornell University, Ithaca, NY), a plant evolutionary biologist, is interested in how plants have changed over the past few million years, in particular their size, shape, structure, and reproduction. As the first article in a series of Centennial Review papers celebrating 100 years of the American ...

One of the key major transitions of evolution involved the emergence of multicellular life forms from single-cell systems [1,2]. The standard view is that groups of cooperating cells are able to take advantage of division of labour in order to better exploit external resources, avoid predators or improve given adaptive traits [3,4]. Yet, the transition multicellularity (MC) encapsulated in this picture involves an increase in overall complexity [5] and thus increasing costs for coordinated cooperating behaviour. The main problem is then to understand what makes the trade-off between these two sides balance out.. Available phylogenetic techniques have shed light on how and when the roots of MC got established [6-9]. Particularly, comparative analyses of different clades of multicellular organisms have proven to be very useful in delineating of the genetic toolkit required for multicellular existence [10]. These studies show that cell-cell communication and adhesion genes were co-opted from ...

Over the past 3.8 billion years, the maximum size of life has increased by approximately 18 orders of magnitude. Much of this increase is associated with two major evolutionary innovations: the evolution of eukaryotes from prokaryotic cells approximately 1.9 billion years ago (Ga), and multicellular life diversifying from unicellular ancestors approximately 0.6 Ga. However, the quantitative relationship between organismal size and structural complexity remains poorly documented. We assessed this relationship using a comprehensive dataset that includes organismal size and level of biological complexity for 11 172 extant genera. We find that the distributions of sizes within complexity levels are unimodal, whereas the aggregate distribution is multimodal. Moreover, both the mean size and the range of size occupied increases with each additional level of complexity. Increases in size range are non-symmetric: the maximum organismal size increases more than the minimum. The majority of the observed ...

Multicellularity has emerged and continues to emerge in a variety of lineages and under diverse environmental conditions. In order to attain individuality and integration, multicellular organisms must exhibit spatial cell differentiation, which in turn allows cell aggregates to robustly generate traits and behaviors at the multicellular level. Nevertheless, the mechanisms that may lead to the development of cellular differentiation and patterning in emerging multicellular organisms remain unclear. We briefly review two conceptual frameworks that have addressed this issue: the cooperation-defection framework and the dynamical patterning modules (DPMs) framework. Then, situating ourselves in the DPM formalism first put forward by S. A. Newman and collaborators, we state a hypothesis for cell differentiation and arrangement in cellular masses of emerging multicellular organisms. Our hypothesis is based on the role of the generic cell-to-cell communication and adhesion patterning mechanisms, which are two

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Genomic study reveals that co-option of genes for cell cycle regulation helped unicellular organisms evolve toward multicellularity

Bosch, Thomas (2012) Rethinking the origin of multicellularity: Where do epithelia come from? (Comment on DOI 10.1002/bies.201100187) Bioessays, 34 (10). pp. 826-827. Full text not available from this repository ...

Channelrhodopsins, the directly light‐gated ion channels from green algae, provide a powerful tool for basic research in neuroscience as well as potential applications for treating neurological diseases and disorders

A xine-lib update is available for Gentoo Linux - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Gentoo Linux Security Advisory GLSA 200408-18 - - - -...

The latter constitute the focus of our current research. A large fraction of the genome is transcribed into RNAs that, despite lacking protein-coding potential, perform important regulatory functions. Like proteins, RNA molecules can fold into complex tertiary structures with elaborate surfaces and cavities that mediate highly specific molecular interactions and even catalyze biochemical reactions; like DNA, RNA can form Watson-Crick base pairs with other RNAs or with DNA itself (Figure 2). In other words, RNA is fluent in two languages: the elaborate three-dimensional discourse of proteins and the linear genetic code of DNA. Thus, it seems fitting that RNAs may act as a molecular bridge-an epigenetic translator-between chromatin-regulating proteins and the genome sequence. Understanding how noncoding RNAs affect the epigenetic states of cells and organisms will provide us with unprecedented access to the regulatory circuitry that makes multicellular life possible. ...

What is cancer? Its not an invader, its spawned from our own bodies. And it bears striking resemblance to early multicellular life from 1 billion years ago. This has led astrobiologists and cosmologists Paul Davies and Charlie Lineweaver to suggest that cancer is driven by primitive genes that gov...

Programmed cell death is an intricately controlled and irreducibly complex process, without which no multicellular life could live.

Using an artificial selection paradigm, researchers watch as unicellular yeast evolve into snowflake-like clusters with distinct multicellular characteristics.

A new security update has been released for Gentoo Linux - Streamripper: Multiple remote buffer overflows. Here the announcement:...

The new taxon corresponds to H13 in Figure 4 above, and the sequenced haplotype of Trichoplax adhaerens to H1. As the authors point out, these are two of the most distantly related haplotypes. Still, the depth of the divergences within Group A, at least based on 16S sequences, suggests that there are likely to be several other placozoan taxa yet to be described.. Just as in the volvocine algae, placozoan taxonomy has until recently been based on morphology. And just as in the volvocine algae, morphology is clearly insufficient to parse deep divergences within this group, though for different reasons. With cheap whole genome sequencing, I expect well see more species, and maybe even higher taxa, described in the next few years.. There is an immense amount we dont know about the placozoa: what are their relationships to other animals, how do they have sex, what is their basic ecology…The landscape of placozoan biology is largely unexplored, and there are likely to be wonders as yet ...

Nozaki, H. (1988). Morphology, sexual reproduction and taxonomy of Volvox carteri f. kawasakiensis f. nov. (Chlorophyta) from Japan. Phycologia 27((2)): 209-220.. Created: 13 March 2006 by M.D. Guiry. Verified by: 19 May 2010 by Wendy Guiry. Accesses: This record has been accessed by users 590 times since it was created.. Verification of data ...

Next-day shipping cDNA ORF clones derived from VOLCADRAFT_97368 hypothetical protein available at GenScript, starting from $99.00.

Multicellularity arose multiple times in the evolutionary history of eukaryotes, and simple multicellularity may have a deep history tracing back to the Paleoproterozoic. However, complex multicellular organisms with cellular and tissue differentiation did not appear in the fossil record until the Mesoproterozoic, and it is not until the Ediacaran Period (635-541 Ma) when diverse assemblages of complex multicellular eukaryotes evolved. In the intervening Tonian Period (ca. 1000-720 Ma), the fossil record of multicellular organisms is poorly documented. To address this knowledge gap, we investigated Chuaria and associated carbonaceous compression fossils from the Tonian Liulaobei Formation in North China. These fossils have been variously interpreted as unicellular or multicellular organisms. Our analysis using backscattered-electron scanning electron microscopy (BSE-SEM) revealed direct evidence for simple multicellularity in some of these fossils and suggests that Chuaria may have had a ...

By Tim Stephens. Optogenetics techniques, which allow scientists to map and control nerve cells using light stimulation, are being used to study neural circuits in the brain with unprecedented precision. This revolutionary technology relies on light-sensitive proteins such as channelrhodopsins, and researchers at UC Santa Cruz have now determined the molecular mechanism involved in the light-induced activation of one of these proteins.. Little was known about the functional mechanism of these proteins even though they are widely used in optogenetics, Kliger said.. The researchers used fast laser spectroscopy to study the function of Channelrhodopsin-2, which is found in a type of marine algae and is widely used in optogenetics experiments. Channelrhodopsins are ion channels that control the flow of ions across cell membranes. There are many kinds of ion channels that serve different purposes in different types of cells. Nerve signals involve ion flow across the membranes of nerve cells, and ...

The introduction of two microbial opsin-based tools, channelrhodopsin-2 (ChR2) and halorhodopsin (NpHR), to neuroscience has generated interest in fast, multimodal, cell type-specific neural circuit control. Here we describe a cation-conducting channelrhodopsin (VChR1) from Volvox carteri that can drive spiking at 589 nm, with excitation maximum red-shifted approximately 70 nm compared with ChR2. These results demonstrate fast photostimulation with yellow light, thereby defining a functionally distinct third category of microbial rhodopsin proteins ...

With contributions from a team of leading experts, this volume provides a comprehensive survey of recent achievements in our scientific understanding of evolution. The questions it asks concern the beginnings of the universe, the origin of life and the chances of its arising at all, the role of

Optical silencing of activity provides a way to test the necessity of neurons in behaviour. Two light-gated anion channels, GtACR1 and GtACR2, have recently been shown to potently inhibit activity in cultured mammalian neurons and in Drosophila. Here, we test the usefulness of these channels in larval zebrafish, using spontaneous coiling behaviour as the assay. When the GtACRs were expressed in spinal neurons of embryonic zebrafish and actuated with blue or green light, spontaneous movement was inhibited. In GtACR1-expressing fish, only 3 μW/mm2 of light was sufficient to have an effect; GtACR2, which is poorly trafficked, required slightly stronger illumination. No inhibition was seen in non-expressing siblings. After light offset, the movement of GtACR-expressing fish increased, which suggested that termination of light-induced neural inhibition may lead to activation. Consistent with this, two-photon imaging of spinal neurons showed that blue light inhibited spontaneous activity in spinal neurons of

The invention, in some aspects relates to compositions and methods for altering cell activity and function and the introduction and use of light-activated ion channels.

Volvox colony. Micrograph of a colony of the freshwater alga Volvox sp. The colony is a hollow sphere made up from thousands of cells connected by cytoplasmic threads and arranged in a single layer. Each cell has two flagella, which point outwards, and ar. - Stock Video Clip K005/1075

One of the most amazing events in biology is the development of a fertilized egg into a complex, mature organism with diverse cell types, tissues, and organs. The field of developmental biology seeks to understand the mechanisms controlling this remarkable process. To do so, developmental biologists use techniques developed in the areas of genetics, molecular biology, biochemistry, and cell biology and ideas derived from the study of gene expression, cell motility, signal transduction and others. As many human diseases such as cancer are really diseases of normal development gone awry, there is also overlap between developmental biology and areas such as cancer biology. Within our department, labs study developmental processes in several model systems, including the cellular amoeba Dictyostelium, the alga Volvox, the plant Arabidopsis, the roundworm C. elegans, as well as prostate and nervous system development in the mouse. ...

Metamorphosis is broadly defined as a more or less radical morphological change between two multicellular life stages within an organism life phase, often marking the transition from pre-reproductive to reproductive stages. It involves structural re-organization and major physiological changes, generally under the control of endogenous and exogenous factors, often resulting in changes in habitat use. This concept has been applied to the crustose-to-erect thallus (hereafter CET ) transition of some red algae and this study evaluates the tenability of such hypothesis. In contrast to the metamorphosis of some invertebrates, the CET transition of red algae does not involve radical morphological changes nor complete morphological remodeling; it may be restricted to only one of the two life phases in species with alternation of generations and often involves only slight microhabitat changes. On the other hand, the CET transition may separate pre- and reproductive stages, the onset of the morphological ...

In our recently published paper1, we showed that mouse stem cells self-organize into blastocyst-like structures, that we termed blastoids. Because blastoids can be generated in large numbers, can be finely manipulated, and implant in utero, they are a powerful tool to investigate the principles of pre- and post-implantation development. Here is the backstory of our[…] ...

Broad perspective Successful division was an essential criterion for establishing the cell as the basic unit of life on earth. Later, cell-cell adhesion made possible the evolution of multicellular life forms. These two fundamental cellular processes co-function throughout the life of an organism, during development, wound healing and tissue regeneration. In epithelial tissues this results[…] ...

It is time for students of the evolutionary process, especially those who have been misquoted and used by the creationists, to state clearly that evolution is a fact, not theory, and that what is at issue within biology are questions of details of the process and the relative importance of different mechanisms of evolution. It is a fact that the earth with liquid water, is more than 3.6 billion years old. It is a fact that cellular life has been around for at least half of that period and that organized multicellular life is at least 800 million years old. It is a fact that major life forms now on earth were not at all represented in the past. There were no birds or mammals 250 million years ago. It is a fact that major life forms of the past are no longer living. There used to be dinosaurs and Pithecanthropus, and there are none now. It is a fact that all living forms come from previous living forms. Therefore, all present forms of life arose from ancestral forms that were different. Birds ...

There are good reasons for any species to think darkly of its own extinction. […]. Simple, single-celled life appeared early in Earths history. A few hundred million whirls around the newborn Sun were all it took to cool our planet and give it oceans, liquid laboratories that run trillions of chemical experiments per second. Somewhere in those primordial seas, energy flashed through a chemical cocktail, transforming it into a replicator, a combination of molecules that could send versions of itself into the future.. For a long time, the descendants of that replicator stayed single-celled. They also stayed busy, preparing the planet for the emergence of land animals, by filling its atmosphere with breathable oxygen, and sheathing it in the ozone layer that protects us from ultraviolet light. Multicellular life didnt begin to thrive until 600 million years ago, but thrive it did. In the space of two hundred million years, life leapt onto land, greened the continents, and lit the fuse on the ...

Whether a worm, a human, or a blue whale, all multicellular life begins as a single-celled egg. From this solitary cell emerges the galaxy of…. ...

Gabon fossils are earliest traces of multicellular life… or are they? These unassuming fossils may be some of the earliest known examples of complex life on Earth, composed of many cells (like animals and plants) rather than just one (like bacteria). They were uncovered in Gabon by a Abderrazak El Albani from the University of Poitiers, and theyre around 2.1 billion years old. They have been preserved in remarkable detail for their age. They are centimetres in length, and El Albani thinks that theyre probably some of the oldest multi-cellular organisms so far discovered. If hes right, theyre half a billion years older than the previous record-holders.. Leading a team of 21 scientists, El Albani has painstakingly analysed the fossils. Their three-dimensional structure came with radial slits, scalloped margins and a complicated folded centre. To the team, these complex patterns tell us that the fossils were not simply rock formations. Instead, they were the remnants of once-living things ...

High density energy storage The conversion of solar energy into chemical energy is the reason for complex multicellular life on Earth. The photophysical reactions of photosynthesis serve as paradigms for artificial systems. The capture of sunlight in photosynthetic reactions at short (fs-ns) times is extremely efficient - and indeed sets benchmarks for all solar catalyst.

Why Everyone Seems to Have Cancer http://www.nytimes.com/2014/01/05/sunday-review/why-everyone-seems-to-have-cancer.html?nl=todaysheadlines&emc=edit_th_20140105&_r=0 Jillian Tamaki By GEORGE JOHNSON Published: January 4, 2014 EVERY New Year when the government publishes its Report to the Nation on the Status of Cancer, it is followed by a familiar lament. We are losing the war against cancer. Graphic Graphic Declining Lethality Half a century ago, the story goes, a person was far more likely to die from heart disease. Now cancer is on the verge of overtaking it as the No. 1 cause of death. Troubling as this sounds, the comparison is unfair. Cancer is, by far, the harder problem - a condition deeply ingrained in the nature of evolution and multicellular life. Given that obstacle, cancer researchers are fighting and even winning smaller battles: reducing the death toll from childhood cancers and preventing - and sometimes curing - cancers that strike people in their prime. But when it comes to ...

The GNOME Structured File Library is an I/O library that can read and write common file types and handle structured formats that provide file-system-in-a-file semantics ...

The GNOME Structured File Library is an I/O library that can read and write common file types and handle structured formats that provide file-system-in-a-file semantics ...

The unicellular ancestor of animals may have harbored some of the molecular tools that its many-celled descendants use to coordinate and direct cell differentiation and function, scientists show.. 0 Comments. ...

Plasmid pFUGW-GtACR1_C102A-EYFP from Dr. John Spudichs lab contains the insert Anion channelrhodopsin GtACR1 step-function mutant C102A and is published in eNeuro. 2018 Jul 10;5(3). pii: eN-MNT-0174-18. doi: 10.1523/ENEURO.0174-18.2018. eCollection 2018 May-Jun. This plasmid is available through Addgene.