Author
Manfred Sumper
Other affiliations: Max Planck Society, University of Würzburg
Bio: Manfred Sumper is an academic researcher from University of Regensburg. The author has contributed to research in topics: Volvox carteri & Volvox. The author has an hindex of 52, co-authored 111 publications receiving 10435 citations. Previous affiliations of Manfred Sumper include Max Planck Society & University of Würzburg.
Topics: Volvox carteri, Volvox, Glycoprotein, Peptide sequence, Fatty acid
Papers published on a yearly basis
Papers
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TL;DR: A set of polycationic peptides isolated from diatom cell walls were shown to generate networks of silica nanospheres within seconds when added to a solution of silicic acid.
Abstract: Diatom cell walls are regarded as a paradigm for controlled production of nanostructured silica, but the mechanisms allowing biosilicification to proceed at ambient temperature at high rates have remained enigmatic. A set of polycationic peptides (called silaffins) isolated from diatom cell walls were shown to generate networks of silica nanospheres within seconds when added to a solution of silicic acid. Silaffins contain covalently modified lysine-lysine elements. The first lysine bears a polyamine consisting of 6 to 11 repeats of the N-methyl-propylamine unit. The second lysine was identified as epsilon-N,N-dimethyl-lysine. These modifications drastically influence the silica-precipitating activity of silaffins.
1,306 citations
TL;DR: Time-resolved analysis of silica morphogenesis in vitro detected a plastic silaffin-silica phase, which may represent a building material for diatom biosilica.
Abstract: Silaffins are uniquely modified peptides that have been implicated in the biogenesis of diatom biosilica. A method that avoids the harsh anhydrous hydrogen fluoride treatment commonly used to dissolve biosilica allows the extraction of silaffins in their native state. The native silaffins carry further posttranslational modifications in addition to their polyamine moieties. Each serine residue was phosphorylated, and this high level of phosphorylation is essential for biological activity. The zwitterionic structure of native silaffins enables the formation of supramolecular assemblies. Time-resolved analysis of silica morphogenesis in vitro detected a plastic silaffin-silica phase, which may represent a building material for diatom biosilica.
734 citations
TL;DR: The chemical structure of long-chain polyamines (up to 20 repeated units), which represent the main organic constituent of diatom biosilica, are described, which are the longest polyamine chains found in nature and induce rapid silica precipitation from a silicic acid solution.
Abstract: Biomineralizing organisms use organic molecules to generate species-specific mineral patterns. Here, we describe the chemical structure of long-chain polyamines (up to 20 repeated units), which represent the main organic constituent of diatom biosilica. These substances are the longest polyamine chains found in nature and induce rapid silica precipitation from a silicic acid solution. Each diatom is equipped with a species-specific set of polyamines and silica-precipitating proteins, which are termed silaffins. Different morphologies of precipitating silica can be generated by polyamines of different chain lengths as well as by a synergistic action of long-chain polyamines and silaffins.
629 citations
TL;DR: In recent years, insight into the molecules and mechanism that allow diatoms to perform silica morphogenesis under ambient conditions has been gained as mentioned in this paper, which is among the most remarkable examples of biological nanofabrication.
Abstract: The stunning silica structures formed by diatoms are among the most remarkable examples of biological nanofabrication. In recent years, insight into the molecules and mechanism that allow diatoms to perform silica morphogenesis under ambient conditions has been gained.
393 citations
TL;DR: In this article, it was shown that diatom biosilica is a composite material containing zwitterionic proteins (silaffins) and long-chain polyamines in addition to silica.
Abstract: Diatoms are eukaryotic, unicellular algae that are ubiquitously present in almost any water habitat on earth Diatoms dominate phytoplankton populations and algal blooms in the oceans They are responsible for about 25 % of the world's net primary production Apart from this ecological significance, diatoms are mainly known for the intricate geometries and spectacular patterns of their silica-based cell walls These patterns are species specific They are precisely reproduced in each generation documenting a genetic control of this biomineralization process Biogenesis of the diatom cell wall is considered to be a paradigm for the controlled production of nanostructured silica Biochemical studies demonstrated that diatom biosilica is a composite material containing zwitterionic proteins (silaffins) and long-chain polyamines in addition to silica Functional studies indicate a crucial role of these organic components in guiding silica precipitation as well as in the formation of species-specific nanopatterns These activities can be explained by molecular self-assembly and phase-separation processes Moreover, diatom cell walls also exhibit very exciting properties from the physical point of view: they are extremely stable and they may act as photonic crystals
387 citations
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TL;DR: This review covers the literature published in 2014 for marine natural products, with 1116 citations referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms.
4,649 citations
TL;DR: The rates of reduction of the metal ions by Neem leaf extract are much faster than those observed by us in earlier studies using microorganisms such as fungi, highlighting the possibility that nanoparticle biological synthesis methodologies will achieve rates of synthesis comparable to those of chemical methods.
2,339 citations
TL;DR: This review is focused on current approaches emerging at the intersection of materials research, nanosciences, and molecular biotechnology, which is closely associated with both the physical and chemical properties of organic and inorganic nanoparticles.
Abstract: Based on fundamental chemistry, biotechnology and materials science have developed over the past three decades into today's powerful disciplines which allow the engineering of advanced technical devices and the industrial production of active substances for pharmaceutical and biomedical applications. This review is focused on current approaches emerging at the intersection of materials research, nanosciences, and molecular biotechnology. This novel and highly interdisciplinary field of chemistry is closely associated with both the physical and chemical properties of organic and inorganic nanoparticles, as well as to the various aspects of molecular cloning, recombinant DNA and protein technology, and immunology. Evolutionary optimized biomolecules such as nucleic acids, proteins, and supramolecular complexes of these components, are utilized in the production of nanostructured and mesoscopic architectures from organic and inorganic materials. The highly developed instruments and techniques of today's materials research are used for basic and applied studies of fundamental biological processes.
2,268 citations
University of Washington1, University of Wisconsin–Milwaukee2, École Normale Supérieure3, University of British Columbia4, University of Wisconsin-Madison5, Princeton University6, Martek Biosciences Corporation7, University of California, Santa Barbara8, University of Melbourne9, University of California, San Diego10, Sandia National Laboratories11, University of California, Santa Cruz12, University of Regensburg13, Oak Ridge National Laboratory14, University of Hull15, Joint Genome Institute16, Academy of Sciences of the Czech Republic17, University of Massachusetts Medical School18, Woods Hole Oceanographic Institution19, Alfred Wegener Institute for Polar and Marine Research20, San Francisco State University21, University of California, Berkeley22
TL;DR: The 34 million-base-pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand base-pair mitochondrial genomes were reported in this article.
Abstract: Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, use of a range of nitrogenous compounds, and a complete urea cycle, all attributes that allow diatoms to prosper in aquatic environments.
1,945 citations
TL;DR: Different methods for the immobilization of enzymes are critically reviewed, with emphasis on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).
Abstract: Immobilization is often the key to optimizing the operational performance of an enzyme in industrial processes, particularly for use in non-aqueous media. Different methods for the immobilization of enzymes are critically reviewed. The methods are divided into three main categories, viz. (i) binding to a prefabricated support (carrier), (ii) entrapment in organic or inorganic polymer matrices, and (iii) cross-linking of enzyme molecules. Emphasis is placed on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).
1,857 citations