The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Thorsten Burmester - One of the best experts on this subject based on the ideXlab platform.

  • globin e is a myoglobin related Respiratory Protein highly expressed in lungfish oocytes
    Scientific Reports, 2019
    Co-Authors: Julia Lüdemann, Igor Schneider, Kellen Matos Verissimo, Kimberley Dreger, Thorsten Burmester
    Abstract:

    Globins are a classical model system for the studies of Protein evolution and function. Recent studies have shown that - besides the well-known haemoglobin and myoglobin - additional globin-types occur in vertebrates that serve different functions. Globin E (GbE) was originally identified as an eye-specific Protein of birds that is distantly related to myoglobin. GbE is also present in turtles and the coelacanth but appeared to have been lost in other vertebrates. Here, we show that GbE additionally occurs in lungfish, the closest living relatives of the tetrapods. Each lungfish species harbours multiple (≥5) GbE gene copies. Surprisingly, GbE is exclusively and highly expressed in oocytes, with mRNA levels that exceed that of myoglobin in the heart. Thus, GbE is the first known oocyte-specific globin in vertebrates. No GbE transcripts were found in the ovary or egg transcriptomes of other vertebrates, suggesting a lungfish-specific function. Spectroscopic analysis and kinetic studies of recombinant GbE1 of the South American lungfish Lepidosiren paradoxa revealed a typical pentacoordinate globin with myoglobin-like O2-binding kinetics, indicating similar functions. Our findings suggest that the multiple copies of GbE evolved to enhance O2-supply in the developing embryo of lungfish, analogous to the embryonic and fetal haemoglobins of other vertebrates. In evolution, GbE must have changed its expression site from oocytes to eyes, or vice versa.

  • Diversity, evolution, and function of myriapod hemocyanins.
    BMC evolutionary biology, 2018
    Co-Authors: Samantha Scherbaum, Christian Pick, Nadja Hellmann, Rosa Fernández, Thorsten Burmester
    Abstract:

    Hemocyanin transports O2 in the hemolymph of many arthropod species. Such Respiratory Proteins have long been considered unnecessary in Myriapoda. As a result, the presence of hemocyanin in Myriapoda has long been overlooked. We analyzed transcriptome and genome sequences from all major myriapod taxa – Chilopoda, Diplopoda, Symphyla, and Pauropoda – with the aim of identifying hemocyanin-like Proteins. We investigated the genomes and transcriptomes of 56 myriapod species and identified 46 novel full-length hemocyanin subunit sequences in 20 species of Chilopoda, Diplopoda, and Symphyla, but not Pauropoda. We found in Cleidogona sp. (Diplopoda, Chordeumatida) a hemocyanin-like sequence with mutated copper-binding centers, which cannot bind O2. An RNA-seq approach showed markedly different hemocyanin mRNA levels from ~ 6 to 25,000 reads per kilobase per million reads. To evaluate the contribution of hemocyanin to O2 transport, we specifically studied the hemocyanin of the centipede Scolopendra dehaani. This species harbors two distinct hemocyanin subunits with low expression levels. We showed cooperative O2 binding in the S. dehaani hemolymph, indicating that hemocyanin supports O2 transport even at low concentration. Further, we demonstrated that hemocyanin is > 1500-fold more highly expressed in the fertilized egg than in the adult. Hemocyanin was most likely the Respiratory Protein in the myriapod stem-lineage, but multiple taxa may have independently lost hemocyanin and thus the ability of efficient O2 transport. In myriapods, hemocyanin is much more widespread than initially appreciated. Some myriapods express hemocyanin only at low levels, which are, nevertheless, sufficient for O2 supply. Notably, also in myriapods, a non-Respiratory Protein similar to insect storage hexamerins evolved from the hemocyanin.

  • Distribution and hypoxia‐regulation of haemocyanin in springtails (Collembola)
    Insect molecular biology, 2017
    Co-Authors: S. Flachsbarth, M. Kruse, Thorsten Burmester
    Abstract:

    Haemocyanin is the copper-containing Respiratory Protein present in many arthropods. In the hexapods, Respiratory Proteins had long been considered unnecessary as sufficient O2 was thought to be obtained via the trachea. Nevertheless, many ametabolous and hemimetabolous hexapod species actually possess haemocyanin. Here we investigated the occurrence of haemocyanin in Collembola (springtails). Haemocyanin was found in 22 collembolan species of the suborders Symphypleona, Tomoceroidea and Entomobryomorpha, demonstrating its widespread occurrence. No haemocyanin was identified in 16 species of these taxa, and it appears to be absent in Poduromorpha. The presence of haemocyanin does not correlate with either the phylogenetic history or lifestyle of the investigated species. We further investigated the function of haemocyanin in Folsomia candida (Entomobryomorpha) by applying different hypoxia regimes. Whereas short-term (1 h) and mild (10% O2 ) hypoxia led to a decrease in haemocyanin mRNA, strong hypoxia (24 h, 1.5% O2 ) resulted in a ∼4300-fold increase in haemocyanin expression. Hypoxia induction of haemocyanin could not be demonstrated in evolutionarily more advanced Hexapoda, where it is restricted to the embryo. The results indicate (1) an important role of haemocyanin in the oxygen supply of F. candida, which may be adaptive in the potentially hypoxic environment in the soil, and (2) a change in haemocyanin function in hexapod evolution.

  • Unusual Diversity of Myoglobin Genes in the Lungfish
    Molecular Biology and Evolution, 2016
    Co-Authors: Jonas Koch, Julia Lüdemann, Rieke Spies, Chris T. Amemiya, Thorsten Burmester
    Abstract:

    Myoglobin is a Respiratory Protein that serves as a model system in a variety of biological fields. Its main function is to deliver and store O2 in the heart and skeletal muscles, but myoglobin is also instrumental in homeostasis of nitric oxide (NO) and detoxification of reactive oxygen species (ROS). Almost every vertebrate harbors a single myoglobin gene; only some cyprinid fishes have two recently duplicated myoglobin genes. Here we show that the West African lungfish Protopterus annectens has at least seven distinct myoglobin genes (PanMb1-7), which diverged early in the evolution of lungfish and showed an enhanced evolutionary rate. These myoglobins are lungfish specific, and no other globin gene was found amplified. The myoglobins are differentially expressed in various lungfish tissues, and the brain is the main site of myoglobin expression. The typical myoglobin-containing tissues, the skeletal muscle and the heart, have much lower myoglobin mRNA levels. Muscle and heart express distinct myoglobins (PanMb1 and PanMb3, respectively). In cell culture, lungfish myoglobins improved cellular survival under hypoxia albeit with different efficiencies and reduced the production of reactive oxygen species. Only Mb2 and Mb6 enhanced the energy status of the cells. The unexpected diversity of myoglobin hints to a functional diversification of this gene: some myoglobins may have adapted to the O2 requirements of the specific tissue and help the lungfish to survive hypoxic periods; other myoglobins may have taken over the roles of neuroglobin and cytoglobin, which appear to be missing in the West African lungfish.

  • Identification and characterisation of hemocyanin of the fish louse Argulus (Crustacea: Branchiura)
    Journal of Comparative Physiology B, 2016
    Co-Authors: Pauline Pinnow, Christian Pick, Andrej Fabrizius, Thorsten Burmester
    Abstract:

    Hemocyanin transports oxygen in the hemolymph of many arthropod species. Within the crustaceans, this copper-containing Protein was thought to be restricted to Malacostraca, while other crustacean classes were assumed to employ hemoglobin or lack any Respiratory Protein. Only recently it has become evident that hemocyanins also occur in Remipedia and Ostracoda. Here we report for the first time the identification and characterisation of hemocyanin in the fish louse Argulus , which belongs to the class of Branchiura. This finding indicates that hemocyanin was the principal oxygen carrier in the stem lineage of the pancrustaceans, but has been lost independently multiple times in crustacean taxa. We obtained the full-length cDNA sequences of two hemocyanin subunits of Argulus foliaceus by a combination of RT-PCR, RACE and Illumina sequencing of the transcriptome. In addition, one full-length and one partial cDNA sequence were derived from the transcriptome data of Argulus siamensis. Western blot analysis confirmed the presence of at least two hemocyanin subunits in A. foliaceus , which are expressed at the mRNA level at a 1:3.5 ratio. The addition to the branchiuran hemocyanin subunits to a multiple sequence alignment of arthropod, hemocyanins improved the phylogenetic resolution within the pancrustacean hemocyanins. Malacostracan, ostracod and branchiuran hemocyanins are distinct from the hexapod and remipede hemocyanins, reinforcing the hypothesis of a close relationship of Remipedia and Hexapoda. Notably, the ostracod hemocyanins are paraphyletic with respect to the branchiuran hemocyanins, indicating ancient divergence and differential loss of distinct subunit types.

Bernhard Lieb - One of the best experts on this subject based on the ideXlab platform.

  • Hemocyanin genes as indicators of habitat shifts in Panpulmonata
    Molecular phylogenetics and evolution, 2018
    Co-Authors: Gabriela Giannina Schäfer, Veronika Pedrini-martha, Raimund Schnegg, Reinhard Dallinger, Daniel J. Jackson, Bernhard Lieb
    Abstract:

    Hemocyanin is the primary Respiratory Protein for the majority of the Mollusca and therefore directly interfaces with the physiological requirements of each species and the environments to which they are adapted. Hemocyanin is therefore likely to have been evolutionarily imprinted by significant habitat shifts. In the gastropod clade Panpulmonata (>30,000 species) major realm transitions have occurred multiple times independently and may have contributed to the diversification of this group. Yet, little is known about the adaptive changes linked to these habitat shifts. In order to gain deeper insight into the evolution of panpulmonate hemocyanins and to infer possible impacts associated with those scenarios, we have assembled and analysed hemocyanin isoforms from 4 panpulmonate species: (i) Helix pomatia, (ii) Cantareus aspersus (both Helicidae, Stylommatophora), (iii) Arion vulgaris (Arionidae, Stylommatophora) and (iv) Lymnaea stagnalis (Lymnaeidae, Hygrophila). Additionally, we describe a new hemocyanin isoform within the genome of the euopisthobranch Aplysia californica. Using these newly acquired hemocyanin data, we performed a phylogenetic analysis that reveals independent duplication events of hemocyanin within lineages that correlate with significant habitat shifts.

  • A new haemocyanin in cuttlefish (Sepia officinalis) eggs: sequence analysis and relevance during ontogeny
    EvoDevo, 2014
    Co-Authors: Anne Thonig, Bernhard Lieb, Michael Oellermann, Felix Christopher Mark
    Abstract:

    Haemocyanin is the Respiratory Protein of most of the Mollusca. In cephalopods and gastropods at least two distinct isoforms are differentially expressed. However, their physiological purpose is unknown. For the common cuttlefish Sepia officinalis, three isoforms are known so far, whereas for only two of them the complete mRNA sequences are available. In this study, we sequenced the complete mRNA of the third haemocyanin isoform and measured the relative expression of all three isoforms during embryogenesis to reveal a potential ontogenetic relevance. The cDNA of isoform 3 clearly correlates to the known Sepia officinalis haemocyanin subunits consisting of eight functional units and an internal duplicated functional unit d. Our molecular phylogenetic analyses reveal the third isoform representing a potentially ancestral haemocyanin isoform, and the analyses of the expression of haemocyanin type 3 reveal that haemocyanin type 3 only can be observed within eggs and during early development. Isoforms 1 and 2 are absent at these stages. After hatching, isoform 3 is downregulated, and isoform 1 and 2 are upregulated. Our study clearly shows an embryonic relevance of the third isoform, which will be further discussed in the light of the changes in the physiological function of haemocyanin during ontogeny. Taken together with the fact that it could also be the isoform closest related to the common ancestor of cuttlefish haemocyanin, the phylogeny of cuttlefish haemocyanin may be recapitulated during its ontogeny.

  • A new haemocyanin in cuttlefish (Sepia officinalis) eggs: sequence analysis and relevance during ontogeny
    EvoDevo, 2014
    Co-Authors: Anne Thonig, Bernhard Lieb, Michael Oellermann, Felix Christopher Mark
    Abstract:

    Background Haemocyanin is the Respiratory Protein of most of the Mollusca. In cephalopods and gastropods at least two distinct isoforms are differentially expressed. However, their physiological purpose is unknown. For the common cuttlefish Sepia officinalis, three isoforms are known so far, whereas for only two of them the complete mRNA sequences are available. In this study, we sequenced the complete mRNA of the third haemocyanin isoform and measured the relative expression of all three isoforms during embryogenesis to reveal a potential ontogenetic relevance. Results The cDNA of isoform 3 clearly correlates to the known Sepia officinalis haemocyanin subunits consisting of eight functional units and an internal duplicated functional unit d. Our molecular phylogenetic analyses reveal the third isoform representing a potentially ancestral haemocyanin isoform, and the analyses of the expression of haemocyanin type 3 reveal that haemocyanin type 3 only can be observed within eggs and during early development. Isoforms 1 and 2 are absent at these stages. After hatching, isoform 3 is downregulated, and isoform 1 and 2 are upregulated. Conclusions Our study clearly shows an embryonic relevance of the third isoform, which will be further discussed in the light of the changes in the physiological function of haemocyanin during ontogeny. Taken together with the fact that it could also be the isoform closest related to the common ancestor of cuttlefish haemocyanin, the phylogeny of cuttlefish haemocyanin may be recapitulated during its ontogeny.

  • Hemocyanin in mollusks--a molecular survey and new data on hemocyanin genes in Solenogastres and Caudofoveata.
    Molecular phylogenetics and evolution, 2008
    Co-Authors: Bernhard Lieb, Christiane Todt
    Abstract:

    The most common Respiratory Protein of mollusks is the blue, copper-containing hemocyanin (van Holde and Miller, 1995). It is not bound to hemocytes but suspended in the hemolymph. Its molecular mass ranges from 3500 10 to 8000 10 Da (dalton) or even more (Herskovits, 1988). These differences in molecular weight are due to the fact that the basic decamers that constitute the barrel-shaped Protein may aggregate to didecamers or multidecameric elongated particles (Herskovits, 1988). In cephalopods and chitons (Polyplacophora), there are exclusively decamers, whereas in protobranch bivalves and gastropods the predominantly observed aggregation state is didecamers (Herskovits, 1988; van Holde andMiller, 1995; Lieb andMarkl, 2004; Bergmann et al., 2006, 2007; Gatsogiannis et al., 2007). A typical hemocyanin monomer is composed of eight globular functional units (FU), which are arranged like pearls on a string and termed FU-a to FU-h. An exception are cephalopod hemocyanins that contain only seven FUs. According to molecular clock calculations, the single FUs evolved within the early Precambrian, thus they were present already before the extant molluscan classes derived (Lieb et al., 2000; Lieb and Markl, 2004). Further analyses of hemocyanin-genes from cephalopods, gastropods, a protobranch bivalve, and polyplacophorans (the latter is unpublished data) showed that all hemocyanin genes possess highly conserved phase 1 linker-introns, which separate the individual FU-exons from each other [(FU-a-intron-FU-b-intron-FU-c-intron-FU-d-intron...) Lieb et al., 2001; Altenhein et al., 2002; Bergmann et al., 2006, 2007]. Since these introns are present in all molluscan hemocyanin genes, they seem to be ancient and probably at first used to border a sin-

  • cdna sequence Protein structure and evolution of the single hemocyanin from aplysia californica an opisthobranch gastropod
    Journal of Molecular Evolution, 2004
    Co-Authors: Bernhard Lieb, Wolfgang Gebauer, Valesca Boisguerin, Jurgen Markl
    Abstract:

    By Protein immunobiochemistry and cDNA sequencing, we have found only a single hemocyanin polypeptide in an opisthobranch gastropod, the sea hare Aplysia californica, which contrasts with previously studied prosobranch gastropods, which express two distinct isoforms of this extracellular Respiratory Protein. We have cloned and sequenced the cDNA encoding the complete polypeptide of Aplysia californica hemocyanin (AcH). The cDNA comprises 11,433 bp, encompassing a 5′UTR of 77 bp, a 3′UTR of 1057 bp, and an open reading frame for a signal peptide of 20 amino acids plus a polypeptide of 3412 amino acids (Mr ca. 387 kDa). This polypeptide is the subunit of the cylindrical native hemocyanin (Mr ca. 8 MDa). It comprises eight different functional units (FUs: a, b, c, d, e, f, g, h) that have been identified immunobiochemically after limited proteolysis of AcH purified from the hemolymph. Each FU shows a highly conserved copper-A and copper-B site for reversible oxygen binding. FU AcH-h carries a specific C-terminal extension of ca. 100 amino acids that include two cysteines that may be utilized for disulfide bridge formation. Potential N-glycosylation sites are present in six FUs but lacking in AcH-b and AcH-c. On the basis of multiple sequence alignments, phylogenetic trees and a statistically firm molecular clock were calculated. The latter suggests that the last common ancestor of Haliotis and Aplysia lived 373 ± 47 million years ago, in convincing agreement with fossil records from the early Devonian. However, the gene duplication yielding the two distinct hemocyanin isoforms found today in Haliotis tuberculata occurred 343 ± 43 million years ago.

Thomas Hankeln - One of the best experts on this subject based on the ideXlab platform.

  • oxygen supply from the bird s eye perspective globin e is a Respiratory Protein in the chicken retina
    Journal of Biological Chemistry, 2011
    Co-Authors: Miriam Blank, Laurent Kiger, Michael C Marden, Thomas Hankeln, Frank Gerlach, Anke Thielebein, Thorsten Burmester
    Abstract:

    The visual process in the vertebrate eye requires high amounts of metabolic energy and thus oxygen. Oxygen supply of the avian retina is a challenging task because birds have large eyes, thick retinae, and high metabolic rates but neither deep retinal nor superficial capillaries. Respiratory Proteins such as myoglobin may enhance oxygen supply to certain tissues, and thus the mammalian retina harbors high amounts of neuroglobin. Globin E (GbE) was recently identified as an eye-specific globin of chicken (Gallus gallus). Orthologous GbE genes were found in zebra finch and turkey genomes but appear to be absent in non-avian vertebrate classes. Analyses of globin phylogeny and gene synteny showed an ancient origin of GbE but did not help to assign it to any specific globin type. We show that the photoreceptor cells of the chicken retina have a high level of GbE Protein, which accumulates to ∼10 μM in the total eye. Quantitative real-time RT-PCR revealed an ∼50,000-fold higher level of GbE mRNA in the eye than in the brain. Spectroscopic analysis and ligand binding kinetics of recombinant chicken GbE reveal a penta-coordinated globin with an oxygen affinity of P(50) = 5.8 torrs at 25 °C and 15 torrs at 41 °C. Together these data suggest that GbE helps to sustain oxygen supply to the avian retina.

  • neuroglobin mrna expression after transient global brain ischemia and prolonged hypoxia in cell culture
    Brain Research, 2006
    Co-Authors: Rainald Schmidtkastner, Mark Haberkamp, Christoph Schmitz, Thomas Hankeln, Thorsten Burmester
    Abstract:

    Abstract Neuroglobin is a nerve-specific Respiratory Protein that has been proposed to play an important role in the protection of brain neurons from ischemic and hypoxic injuries. Here, we investigated the regulation of neuroglobin expression after transient global ischemia in the rat brain using mRNA in situ hybridization and under hypoxic stress in cultured neuronal cell lines (PC12, HN33) by quantitative RT-PCR. While neuroglobin mRNA expression was significantly enhanced in cell culture after severe prolonged hypoxia (0–1% O2 for 24 h), we did not find any significant increases in neuroglobin mRNA levels in the rat brain after transient global ischemia. Vegf and Glut1 mRNAs showed increases in the hippocampus as expected. Therefore, it is unlikely that neuroglobin is instrumental in the acute response of neurons to hypoxic or ischemic insults, for which the mammalian brain is not adapted.

  • divergent distribution in vascular and avascular mammalian retinae links neuroglobin to cellular respiration
    Journal of Biological Chemistry, 2005
    Co-Authors: Anke Bentmann, Stefan Reuss, Marc Schmidt, Uwe Wolfrum, Thomas Hankeln, Thorsten Burmester
    Abstract:

    The visual function of the vertebrate retina relies on sufficient supply with oxygen. Neuroglobin is a Respiratory Protein thought to play an essential role in oxygen homeostasis of neuronal cells. For further understanding of its function, we compared the distribution of neuroglobin and mitochondria in both vascular and avascular mammalian retinae. In the vascular retinae of mouse and rat, oxygen is supplied by the outer choroidal, deep retinal, and inner capillaries. We show that in this type of retina, mitochondria are concentrated in the inner segments of photoreceptor cells, the outer and the inner plexiform layers, and the ganglion cell layer. These are the same regions in which oxygen consumption takes place and in which neuroglobin is present at high levels. In the avascular retina of guinea pig the deep retinal and inner capillaries are absent. Therefore, only the inner segments of the photoreceptors adjacent to choroidal capillaries display an oxidative metabolism. We demonstrate that in the retina of guinea pigs both neuroglobin and mitochondria are restricted to this layer. Our results clearly demonstrate an association of neuroglobin and mitochondria, thus supporting the hypothesis that neuroglobin is a Respiratory Protein that supplies oxygen to the Respiratory chain.

  • zebrafish reveals different and conserved features of vertebrate neuroglobin gene structure expression pattern and ligand binding
    Journal of Biological Chemistry, 2004
    Co-Authors: Christine Fuchs, Anja Roesner, Marc Schmidt, Valeska Heib, Mark Haberkamp, Djemel Hamdane, Laurent Kiger, Michael C Marden, Thomas Hankeln, Thorsten Burmester
    Abstract:

    Abstract Neuroglobin has been identified as a Respiratory Protein that is primarily expressed in the mammalian nervous system. Here we present the first detailed analysis of neuroglobin from a non-mammalian vertebrate, the zebrafish Danio rerio. The zebrafish neuroglobin gene reveals a mammalian-type exon-intron pattern in the coding region (B12.2, E11.0, and G7.0), plus an additional 5′-non-coding exon. Similar to the mammalian neuroglobin, the zebrafish Protein displays a hexacoordinate deoxy-binding scheme. Flash photolysis kinetics show the competitive binding on the millisecond timescale of external ligands and the distal histidine, resulting in an oxygen affinity of 1 torr. Western blotting, immune staining, and mRNA in situ hybridization demonstrate neuroglobin expression in the fish central nervous system and the retina but also in the gills. Neurons containing neuroglobin have a widespread distribution in the brain but are also present in the olfactory system. In the fish retina, neuroglobin is mainly present in the inner segments of the photoreceptor cells. In the gills, the chloride cells were identified to express neuroglobin. Neuroglobin appears to be associated with mitochondria-rich cell types and thus oxygen consumption rates, suggesting a myoglobin-like function of this Protein in facilitated oxygen diffusion.

  • neuroglobin a Respiratory Protein of the nervous system
    Physiology, 2004
    Co-Authors: Thorsten Burmester, Thomas Hankeln
    Abstract:

    Nerve tissues exhibit some of the highest oxygen consumption rates found in the body. Neuroglobin, a heme Protein distantly related to hemoglobin, is thought to enhance the supply of oxygen to the neurons, the eye, and some endocrine tissues. Neuroglobin may promote neuronal survival under hypoxic conditions as they occur, for example, in stroke.

Heinz Decker - One of the best experts on this subject based on the ideXlab platform.

  • Jumping on the Edge—First Evidence for a 2 × 6-meric Hemocyanin in Springtails
    Biomolecules, 2019
    Co-Authors: Juliane Schmidt, Heinz Decker, Michael Thomas Marx
    Abstract:

    Hemocyanins are Respiratory dioxygen carrier Proteins found in many arthropods including ancient terrestrial species such as spiders and scorpions as well as marine horseshoe crabs. As hemocyanins are highly conserved in this lineage, it is possible to observe an evolutionary descent through its subunits and their overall structure. Unfortunately, little is known about the structure and function of hexapod hemocyanins. Using recent springtail taxa (Collembola) as models for basal hexapods, and the help of electron microscopy, light scattering, SDS PAGE, and Western blot, we could demonstrate for the first time the presence of 2 × 6-meric hemocyanins in the hemolymph of hexapods. The quaternary structure is composed of at least two different subunits and looks nearly identical to the hemocyanin found in decapod crustaceans. In addition, homology modeling and western blotting suggest a close structural relationship between collembolan and crustacean hemocyanin. Such a Respiratory Protein was possibly helpful in the early terrestrialization process of ancient Collembola. In addition, physiological adaptations to hypoxic or temporarily anoxic conditions could be a possible explanation for the presence of this Respiratory Protein. Nevertheless, it has to be concluded that the primary benefit of hemocyanin for springtails remains unclear.

  • a Respiratory hemocyanin from an insect
    Proceedings of the National Academy of Sciences of the United States of America, 2004
    Co-Authors: Silke Hagnerholler, Heinz Decker, Axel Schoen, Wolfgang Erker, James H Marden, Rainer Rupprecht, Thorsten Burmester
    Abstract:

    Insects possess an elaborate tracheal system that enables transport of gaseous oxygen from the atmosphere directly to the inner organs. Therefore, the presence of specialized oxygen-transport Proteins in the circulatory system of insects has been considered generally unnecessary. Here, we show for the first time, to our knowledge, the presence of an ancestral and functional hemocyanin (Hc) in an insect. In the hemolymph of nymphs and adults of the stonefly Perla marginata, a hexameric Hc was identified, which consists of two distinct subunit types of 659 and 655 amino acids. P. marginata Hc displays cooperative oxygen binding with a moderately high oxygen affinity [(half-saturation pressure, P50 ≈8 torr (1 torr = 133 Pa)]. No evidence was found for the presence of Hcs in the more evolutionarily advanced holometabolan insects, suggesting that this type of Respiratory Protein was lost later in insect evolution. However, our results demonstrate that, in contrast to the accepted paradigm, certain basal insects have retained an ancestral blood-based mechanism of gas exchange.

  • Small-angle X-ray Scattering-based Three-dimensional Reconstruction of the Immunogen KLH1 Reveals Different Oxygen-dependent Conformations
    The Journal of biological chemistry, 2003
    Co-Authors: Hermann Hartmann, André Bongers, Heinz Decker
    Abstract:

    For decades the Respiratory Protein keyhole limpet hemocyanin (KLH1) from the marine gastropod Megathura crenulata has been used widely as a potent immunostimulant, useful hapten carrier, and valuable agent in the treatment of bladder carcinoma. Although much information on the immunological properties of KLH1 is available, biochemical and structural data are still incomplete. Small-angle x-ray scattering revealed the existence of two conformations, an oxy state being slightly more compact than the deoxy state. Based on small-angle scattering curves, a newly developed Monte Carlo algorithm delivered a surface representation of Proteins. The massive changes of the surfaces of reconstructed didecameric KLH1 molecules are explained as a twist of the two non-covalently associated decameric half-molecules. Upon oxygenation, the KLH1 molecule becomes longer and skinnier. This study provides the first real evidence how a molluscan hemocyanin changes conformation during an allosteric transition.

  • Small-angle neutron scattering reveals an oxygen-dependent conformational change of the immunogen keyhole limpet hemocyanin type 1 (KLH1)
    European Biophysics Journal, 2001
    Co-Authors: Hermann Hartmann, André Bongers, Heinz Decker
    Abstract:

    The Respiratory Protein of the keyhole limpet, Megathura crenulata , the hemocyanin (KLH), commonly used as an immunogen, binds oxygen cooperatively, which implies the existence of different conformations. For the first time, two different conformations of KLH1 were detected upon oxygenation, a deoxy and an oxy state, using small-angle neutron scattering. Rearrangements in the quaternary structure of KLH1 were predicted from the different radii of gyration and the shifts of the minima and maxima in the scattering curves. Upon oxygenation, KLH1 becomes smaller and more compact. Model reconstruction of KLH1 indicates a hollow cylinder with two rings located close to both ends, which move slightly together upon oxygenation.

  • SPIDER HEMOCYANIN BINDS ECDYSONE AND 20-OH-ECDYSONE
    The Journal of biological chemistry, 1999
    Co-Authors: Elmar Jaenicke, Roman Föll, Heinz Decker
    Abstract:

    Abstract Fluorescence quenching studies and binding experiments with [3H]ecdysone reveal that the Respiratory Protein, hemocyanin, of the tarantula Eurypelma californicum binds ecdysone. The binding constant for ecdysone ranges between 0.5 and 5 mm, indicating a low affinity binding. However, it is comparable with those found for the ecdysone binding to hexamerins from insects. Based on a comparison of sequences and x-ray structures of arthropodan hemocyanins, we propose an evolutionary conserved hydrophobic pocket in domain 1 of the hemocyanin subunit that may bind ecdysone.

Felix Christopher Mark - One of the best experts on this subject based on the ideXlab platform.

  • A new haemocyanin in cuttlefish (Sepia officinalis) eggs: sequence analysis and relevance during ontogeny
    EvoDevo, 2014
    Co-Authors: Anne Thonig, Bernhard Lieb, Michael Oellermann, Felix Christopher Mark
    Abstract:

    Haemocyanin is the Respiratory Protein of most of the Mollusca. In cephalopods and gastropods at least two distinct isoforms are differentially expressed. However, their physiological purpose is unknown. For the common cuttlefish Sepia officinalis, three isoforms are known so far, whereas for only two of them the complete mRNA sequences are available. In this study, we sequenced the complete mRNA of the third haemocyanin isoform and measured the relative expression of all three isoforms during embryogenesis to reveal a potential ontogenetic relevance. The cDNA of isoform 3 clearly correlates to the known Sepia officinalis haemocyanin subunits consisting of eight functional units and an internal duplicated functional unit d. Our molecular phylogenetic analyses reveal the third isoform representing a potentially ancestral haemocyanin isoform, and the analyses of the expression of haemocyanin type 3 reveal that haemocyanin type 3 only can be observed within eggs and during early development. Isoforms 1 and 2 are absent at these stages. After hatching, isoform 3 is downregulated, and isoform 1 and 2 are upregulated. Our study clearly shows an embryonic relevance of the third isoform, which will be further discussed in the light of the changes in the physiological function of haemocyanin during ontogeny. Taken together with the fact that it could also be the isoform closest related to the common ancestor of cuttlefish haemocyanin, the phylogeny of cuttlefish haemocyanin may be recapitulated during its ontogeny.

  • A new haemocyanin in cuttlefish (Sepia officinalis) eggs: sequence analysis and relevance during ontogeny
    EvoDevo, 2014
    Co-Authors: Anne Thonig, Bernhard Lieb, Michael Oellermann, Felix Christopher Mark
    Abstract:

    Background Haemocyanin is the Respiratory Protein of most of the Mollusca. In cephalopods and gastropods at least two distinct isoforms are differentially expressed. However, their physiological purpose is unknown. For the common cuttlefish Sepia officinalis, three isoforms are known so far, whereas for only two of them the complete mRNA sequences are available. In this study, we sequenced the complete mRNA of the third haemocyanin isoform and measured the relative expression of all three isoforms during embryogenesis to reveal a potential ontogenetic relevance. Results The cDNA of isoform 3 clearly correlates to the known Sepia officinalis haemocyanin subunits consisting of eight functional units and an internal duplicated functional unit d. Our molecular phylogenetic analyses reveal the third isoform representing a potentially ancestral haemocyanin isoform, and the analyses of the expression of haemocyanin type 3 reveal that haemocyanin type 3 only can be observed within eggs and during early development. Isoforms 1 and 2 are absent at these stages. After hatching, isoform 3 is downregulated, and isoform 1 and 2 are upregulated. Conclusions Our study clearly shows an embryonic relevance of the third isoform, which will be further discussed in the light of the changes in the physiological function of haemocyanin during ontogeny. Taken together with the fact that it could also be the isoform closest related to the common ancestor of cuttlefish haemocyanin, the phylogeny of cuttlefish haemocyanin may be recapitulated during its ontogeny.