Articoli di riviste: "Intracellular biomineralization"

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Lemloh, Marie Louise. "Biomineralization in Ciliates". Key Engineering Materials 672 (gennaio 2016): 40–46. http://dx.doi.org/10.4028/www.scientific.net/kem.672.40.

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From a biomineralization point of view, the protist world is far less investigated than its metazoan counterpart. However, eukaryotic single-celled organisms offer a very unique access to discover biomineralization mechanisms in vivo. With respect to intracellular mechanisms involved in ion enrichment, mineral transport or vesicle formation ciliates represent a good model system. One important group of protists, the ciliates, is very common and numerous studies have been performed on their ecology, cell biology, morphology or genetics. Ciliates are also known for their formation of diverse mineralized intracellular and extracellular structures. However, only limited numbers of detailed studies on the kind of minerals, their properties or their formation mechanisms have been reported so far. This article reviews older and more recent literature on biomineralization in ciliates.

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Song, Zhiyong, Long Liu, Xiaoyu Wang, Yongqiang Deng, Qinggong Nian, Guangchuan Wang, Shunya Zhu et al. "Intracellular delivery of biomineralized monoclonal antibodies to combat viral infection". Chemical Communications 52, n. 9 (2016): 1879–82. http://dx.doi.org/10.1039/c5cc09252c.

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Conventional therapeutic monoclonal antibodies (mAbs) are invalid for intracellular viruses but by using in situ biomineralization treatment, they can be successfully delivered into cells to inhibit intracellular viral replication.

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Uebe, René, Birgit Voigt, Thomas Schweder, Dirk Albrecht, Emanuel Katzmann, Claus Lang, Lars Böttger, Berthold Matzanke e Dirk Schüler. "Deletion of a fur-Like Gene Affects Iron Homeostasis and Magnetosome Formation in Magnetospirillum gryphiswaldense". Journal of Bacteriology 192, n. 16 (18 giugno 2010): 4192–204. http://dx.doi.org/10.1128/jb.00319-10.

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ABSTRACT Magnetotactic bacteria synthesize specific organelles, the magnetosomes, which are membrane-enveloped crystals of the magnetic mineral magnetite (Fe3O4). The biomineralization of magnetite involves the uptake and intracellular accumulation of large amounts of iron. However, it is not clear how iron uptake and biomineralization are regulated and balanced with the biochemical iron requirement and intracellular homeostasis. In this study, we identified and analyzed a homologue of the ferric uptake regulator Fur in Magnetospirillum gryphiswaldense, which was able to complement a fur mutant of Escherichia coli. A fur deletion mutant of M. gryphiswaldense biomineralized fewer and slightly smaller magnetite crystals than did the wild type. Although the total cellular iron accumulation of the mutant was decreased due to reduced magnetite biomineralization, it exhibited an increased level of free intracellular iron, which was bound mostly to a ferritin-like metabolite that was found significantly increased in Mössbauer spectra of the mutant. Compared to that of the wild type, growth of the fur mutant was impaired in the presence of paraquat and under aerobic conditions. Using a Fur titration assay and proteomic analysis, we identified constituents of the Fur regulon. Whereas the expression of most known magnetosome genes was unaffected in the fur mutant, we identified 14 proteins whose expression was altered between the mutant and the wild type, including five proteins whose genes constitute putative iron uptake systems. Our data demonstrate that Fur is a regulator involved in global iron homeostasis, which also affects magnetite biomineralization, probably by balancing the competing demands for biochemical iron supply and magnetite biomineralization.

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Sun, Bin, Junbing Jiang, Jiali Tao e Zuozhen Han. "Biomineralization of Carbonates Induced by Mucilaginibacter gossypii HFF1: Significant Role of Biochemical Parameters". Minerals 12, n. 5 (12 maggio 2022): 614. http://dx.doi.org/10.3390/min12050614.

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Although the precipitation of carbonate minerals induced by various bacteria is widely studied, the changes in the biochemical parameters, and their significant role in the biomineralization processes, still need further exploration. In this study, Mucilaginibacter gossypii HFF1 was isolated, identified, and used to induce carbonate minerals at various Mg/Ca ratios. The biochemical parameters were determined in order to explore the biomineralization mechanisms, including cell concentration, pH, ammonia, carbonic anhydrase activity, and alkaline phosphatase activity. The characteristics of extracellular minerals and intracellular inclusions were both analyzed. In addition, the amino acid composition of the extracellular polymeric substance was also tested. Results show that the biochemical parameters provide an alkaline environment for precipitation, due to the combined effect of ammonia, carbonic anhydrase, and alkaline phosphatase. Biotic minerals are characterized by preferred orientation, specific shape, and better crystalline and better thermal stability, indicating their biogenesis. Most of the amino acids in the extracellular polymeric substance are negatived charged, and facilitate the binding of magnesium and calcium ions. The particles with weak crystalline structure in the EPS prove that it acts as a nucleation site. Intracellular analyses prove the presence of the intracellular amorphous inclusions. Our results suggest that the changes in the biochemical parameters caused by bacteria are beneficial to biomineralization, and play a necessary role in its process. This offers new insight into understanding the biomineralization mechanism of the bacteria HFF1.

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Benzerara, K., F. Skouri-Panet, J. Li, C. Ferard, M. Gugger, T. Laurent, E. Couradeau et al. "Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria". Proceedings of the National Academy of Sciences 111, n. 30 (9 luglio 2014): 10933–38. http://dx.doi.org/10.1073/pnas.1403510111.

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Li, Jinhua, Isabel Margaret Oliver, Nithavong Cam, Thomas Boudier, Marine Blondeau, Eric Leroy, Julie Cosmidis et al. "Biomineralization Patterns of Intracellular Carbonatogenesis in Cyanobacteria: Molecular Hypotheses". Minerals 6, n. 1 (3 febbraio 2016): 10. http://dx.doi.org/10.3390/min6010010.

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Xie, Beibei, Huichao Zhao, Yuan-Fu Ding, Ziyi Wang, Yan Wang, Cheng Gao e Ruibing Wang. "Drug-free tumor therapy via spermine-responsive intracellular biomineralization". Journal of Controlled Release 357 (maggio 2023): 572–79. http://dx.doi.org/10.1016/j.jconrel.2023.04.018.

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Martignier, Agathe, Montserrat Filella, Kilian Pollok, Michael Melkonian, Michael Bensimon, François Barja, Falko Langenhorst, Jean-Michel Jaquet e Daniel Ariztegui. "Marine and freshwater micropearls: biomineralization producing strontium-rich amorphous calcium carbonate inclusions is widespread in the genus <i>Tetraselmis</i> (Chlorophyta)". Biogeosciences 15, n. 21 (7 novembre 2018): 6591–605. http://dx.doi.org/10.5194/bg-15-6591-2018.

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Abstract. Unicellular algae play important roles in the biogeochemical cycles of numerous elements, particularly through the biomineralization capacity of certain species (e.g., coccolithophores greatly contributing to the “organic carbon pump” of the oceans), and unidentified actors of these cycles are still being discovered. This is the case of the unicellular alga Tetraselmis cordiformis (Chlorophyta) that was recently discovered to form intracellular mineral inclusions, called micropearls, which had been previously overlooked. These intracellular inclusions of hydrated amorphous calcium carbonates (ACCs) were first described in Lake Geneva (Switzerland) and are the result of a novel biomineralization process. The genus Tetraselmis includes more than 30 species that have been widely studied since the description of the type species in 1878. The present study shows that many other Tetraselmis species share this biomineralization capacity: 10 species out of the 12 tested contained micropearls, including T. chui, T. convolutae, T. levis, T. subcordiformis, T. suecica and T. tetrathele. Our results indicate that micropearls are not randomly distributed inside the Tetraselmis cells but are located preferentially under the plasma membrane and seem to form a definite pattern, which differs among species. In Tetraselmis cells, the biomineralization process seems to systematically start with a rod-shaped nucleus and results in an enrichment of the micropearls in Sr over Ca (the Sr∕Ca ratio is more than 200 times higher in the micropearls than in the surrounding water or growth medium). This concentrating capacity varies among species and may be of interest for possible bioremediation techniques regarding radioactive 90Sr water pollution. The Tetraselmis species forming micropearls live in various habitats, indicating that this novel biomineralization process takes place in different environments (marine, brackish and freshwater) and is therefore a widespread phenomenon.

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Martignier, A., M. Pacton, M. Filella, J. M. Jaquet, F. Barja, K. Pollok, F. Langenhorst et al. "Intracellular amorphous carbonates uncover a new biomineralization process in eukaryotes". Geobiology 15, n. 2 (30 settembre 2016): 240–53. http://dx.doi.org/10.1111/gbi.12213.

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Han, Zuozhen, Xiao Gao, Hui Zhao, Maurice Tucker, Yanhong Zhao, Zhenpeng Bi, Juntong Pan, Guangzhen Wu e Huaxiao Yan. "Extracellular and Intracellular Biomineralization Induced by Bacillus licheniformis DB1-9 at Different Mg/Ca Molar Ratios". Minerals 8, n. 12 (11 dicembre 2018): 585. http://dx.doi.org/10.3390/min8120585.

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Biomineralization has become a research hotspot and attracted widespread attention in the field of carbonate sedimentology. In this study, precipitation of carbonate minerals was induced by Bacillus licheniformis DB1-9 bacteria, (identity confirmed with its phylogenetic tree), to further explore the biomineralization mechanisms. During experiments, lasting up to 24 days with varying Mg/Ca molar ratios and regular monitoring of conditions, ammonia and carbonic anhydrase are released by the bacteria, resulting in a pH increase. Carbonic anhydrase could have promoted carbon dioxide hydration to produce bicarbonate and carbonate ions, and so promoted supersaturation to facilitate the precipitation of carbonate minerals. These include rhombohedral, dumbbell-shaped, and elongated calcite crystals; aragonite appears in the form of mineral aggregates. In addition, spheroidal and fusiform minerals are precipitated. FTIR results show there are organic functional groups, such as C–O–C and C=O, as well as the characteristic peaks of calcite and aragonite; these indicate that there is a close relationship between the bacteria and the minerals. Ultrathin slices of the bacteria analyzed by HRTEM, SAED, EDS, and STEM show that precipitate within the extracellular polymeric substances (EPS) has a poor crystal structure, and intracellular granular areas have no crystal structure. Fluorescence intensity and STEM results show that calcium ions can be transported from the outside to the inside of the cells. This study provides further insights to our understanding of biomineralization mechanisms induced by microorganisms.

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Li, Jinhua, Nicolas Menguy, Christophe Gatel, Victor Boureau, Etienne Snoeck, Gilles Patriarche, Eric Leroy e Yongxin Pan. "Crystal growth of bullet-shaped magnetite in magnetotactic bacteria of the Nitrospirae phylum". Journal of The Royal Society Interface 12, n. 103 (febbraio 2015): 20141288. http://dx.doi.org/10.1098/rsif.2014.1288.

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Magnetotactic bacteria (MTB) are known to produce single-domain magnetite or greigite crystals within intracellular membrane organelles and to navigate along the Earth's magnetic field lines. MTB have been suggested as being one of the most ancient biomineralizing metabolisms on the Earth and they represent a fundamental model of intracellular biomineralization. Moreover, the determination of their specific crystallographic signature (e.g. structure and morphology) is essential for palaeoenvironmental and ancient-life studies. Yet, the mechanisms of MTB biomineralization remain poorly understood, although this process has been extensively studied in several cultured MTB strains in the Proteobacteria phylum. Here, we show a comprehensive transmission electron microscopy (TEM) study of magnetic and structural properties down to atomic scales on bullet-shaped magnetites produced by the uncultured strain MYR-1 belonging to the Nitrospirae phylum, a deeply branching phylogenetic MTB group. We observed a multiple-step crystal growth of MYR-1 magnetite: initial isotropic growth forming cubo-octahedral particles (less than approx. 40 nm), subsequent anisotropic growth and a systematic final elongation along [001] direction. During the crystal growth, one major {111} face is well developed and preserved at the larger basal end of the crystal. The basal {111} face appears to be terminated by a tetrahedral–octahedral-mixed iron surface, suggesting dimensional advantages for binding protein(s), which may template the crystallization of magnetite. This study offers new insights for understanding magnetite biomineralization within the Nitrospirae phylum.

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Yan, Huaxiao, Daniel Cosmos Owusu, Zuozhen Han, Hui Zhao, Bei Ji, Yanyang Zhao, Maurice E. Tucker e Yanhong Zhao. "Extracellular, Surface, and Intracellular Biomineralization of Bacillus subtilis Daniel-1 Bacteria". Geomicrobiology Journal 38, n. 8 (20 giugno 2021): 698–708. http://dx.doi.org/10.1080/01490451.2021.1937406.

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Nam, Onyou, Iwane Suzuki, Yoshihiro Shiraiwa e EonSeon Jin. "Association of Phosphatidylinositol-Specific Phospholipase C with Calcium-Induced Biomineralization in the Coccolithophore Emiliania huxleyi". Microorganisms 8, n. 9 (10 settembre 2020): 1389. http://dx.doi.org/10.3390/microorganisms8091389.

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Biomineralization by calcifying microalgae is a precisely controlled intracellular calcification process that produces delicate calcite scales (or coccoliths) in the coccolithophore Emiliania huxleyi (Haptophycea). Despite its importance in biogeochemical cycles and the marine environment globally, the underlying molecular mechanism of intracellular coccolith formation, which requires calcium, bicarbonate, and coccolith-polysaccharides, remains unclear. In E. huxleyi CCMP 371, we demonstrated that reducing the calcium concentration from 10 (ambient seawater) to 0.1 mM strongly restricted coccolith production, which was then recovered by adding 10 mM calcium, irrespective of inorganic phosphate conditions, indicating that coccolith production could be finely controlled by the calcium supply. Using this strain, we investigated the expression of differentially expressed genes (DEGs) to observe the cellular events induced by changes in calcium concentrations. Intriguingly, DEG analysis revealed that the phosphatidylinositol-specific phospholipase C (PI-PLC) gene was upregulated and coccolith production by cells was blocked by the PI-PLC inhibitor U73122 under conditions closely associated with calcium-induced calcification. These findings imply that PI-PLC plays an important role in the biomineralization process of the coccolithophore E. huxleyi.

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Han, Yu, Bin Sun, Huaxiao Yan, Maurice E. Tucker, Yanhong Zhao, Jingxuan Zhou, Yifan Zhao e Hui Zhao. "Biomineralization of Carbonate Minerals Induced by The Moderate Halophile Staphylococcus Warneri YXY2". Crystals 10, n. 2 (22 gennaio 2020): 58. http://dx.doi.org/10.3390/cryst10020058.

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Although biomineralization of minerals induced by microorganisms has been widely reported, the mechanisms of biomineralization and the characteristics of the biominerals precipitated needs to be studied further. In this study, Staphylococcus warneri YXY2, a moderate halophile, was used to induce the precipitation of carbonate minerals at various Mg/Ca molar ratios. To investigate the biomineralization mechanism, the growth curve, pH changes, ammonia test, the concentration of bicarbonate and carbonate ions, and the activity of carbonic anhydrase (CA) and alkaline phosphatase (ALP) were determined. X-ray powder diffraction (XRD), scanning electron microscopy - energy disperse spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and stable carbon isotope analyses were used to characterize the minerals. The obtained biotic minerals were calcite, vaterite, Mg-rich calcite, and aragonite crystals. The crystallinity of aragonite decreased with increasing Mg/Ca ratios. The preferred orientation, diverse morphologies, organic substances, and more negative stable carbon isotope values proved the biogenesis of these carbonate minerals. The presence of Mg in the biotic aragonite crystals was likely related to the acidic amino acids which also facilitated the nucleation of minerals on/in the extracellular polymeric substances (EPS). Mg2+ and Ca2+ ions were able to enter into the YXY2 bacteria to induce intracellular biomineralization. Dynamics simulation using Material Studio software proved that different adsorption energies of Glutamic acid (Glu) adsorbed onto different crystal planes of aragonite led to the preferred orientation of aragonite. This study helps to deepen our understanding of biomineralization mechanisms and may be helpful to distinguish biotic minerals from abiotic minerals.

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Zhao, Yanyang, Zuozhen Han, Huaxiao Yan, Hui Zhao, Maurice E. Tucker, Mei Han, Guangzhou Mao e Junxiao Yin. "Intracellular and Extracellular Biomineralization Induced by Klebsiella pneumoniae LH1 Isolated from Dolomites". Geomicrobiology Journal 37, n. 3 (23 novembre 2019): 262–78. http://dx.doi.org/10.1080/01490451.2019.1695023.

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Zhu, Xiaohui, Adam P. Hitchcock, Dennis A. Bazylinski, Peter Denes, John Joseph, Ulysses Lins, Stefano Marchesini, Hung-Wei Shiu, Tolek Tyliszczak e David A. Shapiro. "Measuring spectroscopy and magnetism of extracted and intracellular magnetosomes using soft X-ray ptychography". Proceedings of the National Academy of Sciences 113, n. 51 (7 dicembre 2016): E8219—E8227. http://dx.doi.org/10.1073/pnas.1610260114.

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Characterizing the chemistry and magnetism of magnetotactic bacteria (MTB) is an important aspect of understanding the biomineralization mechanism and function of the chains of magnetosomes (Fe3O4nanoparticles) found in such species. Images and X-ray absorption spectra (XAS) of magnetosomes extracted from, and magnetosomes in, wholeMagnetovibrio blakemoreistrain MV-1 cells have been recorded using soft X-ray ptychography at the Fe 2p edge. A spatial resolution of 7 nm is demonstrated. Precursor-like and immature magnetosome phases in a whole MV-1 cell were visualized, and their Fe 2p spectra were measured. Based on these results, a model for the pathway of magnetosome biomineralization for MV-1 is proposed. Fe 2p X-ray magnetic circular dichroism (XMCD) spectra have been derived from ptychography image sequences recorded using left and right circular polarization. The shape of the XAS and XMCD signals in the ptychographic absorption spectra of both sample types is identical to the shape and signals measured with conventional bright-field scanning transmission X-ray microscope. A weaker and inverted XMCD signal was observed in the ptychographic phase spectra of the extracted magnetosomes. The XMCD ptychographic phase spectrum of the intracellular magnetosomes differed from the ptychographic phase spectrum of the extracted magnetosomes. These results demonstrate that spectro-ptychography offers a superior means of characterizing the chemical and magnetic properties of MTB at the individual magnetosome level.

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Sun, Bingbing, e Hong Shen. "Controlling Surface-Induced Nanocomposites by Lipoplexes for Enhanced Gene Transfer". Journal of Nanomaterials 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/784836.

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Surface-induced biomineralization represents a flexible approach to immobilizing DNA onto biomaterial surfaces for surface-mediated DNA delivery. Immobilized naked DNA is uniformly embedded in thin films of nanocomposites, which limits the internalization of DNA to some cell types, such as neuronal cells. In this study, DNA molecules were initially complexed with liposomes to form lipoplexes. Subsequently, these lipoplexes were immobilized onto a cell culture compatible surface through surface-induced biomineralization. Under all the conditions we examined, lipoplexes were efficiently immobilized onto the surface and formed lipoplex-nanocomposites. We have shown that the size of liposomes and the composition of mineralizing solutions have significant effects on the morphology and topology of nanocomposites and thus the organization and the intracellular levels of DNA. The transgene expression mediated by lipoplex-nanocomposites was greatly enhanced in neuronal cells compared to the immobilized naked DNA.

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Butler, Clive S., Charles M. Debieux, Elizabeth J. Dridge, Peter Splatt e Matthew Wright. "Biomineralization of selenium by the selenate-respiring bacterium Thauera selenatis". Biochemical Society Transactions 40, n. 6 (21 novembre 2012): 1239–43. http://dx.doi.org/10.1042/bst20120087.

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Bacterial anaerobic respiration using selenium oxyanions as the sole electron acceptor primarily result in the precipitation of selenium biominerals observed as either intracellular or extracellular selenium deposits. Although a better understanding of the enzymology of bacterial selenate reduction is emerging, the processes by which the selenium nanospheres are constructed, and in some cases secreted, has remained poorly studied. Thauera selenatis is a Gram-negative betaproteobacterium that is capable of respiring selenate due to the presence of a periplasmic selenate reductase (SerABC). SerABC is a molybdoenzyme that catalyses the reduction of selenate to selenite by accepting electrons from the Q-pool via a dihaem c-type cytochrome (cytc4). The product selenite is presumed to be reduced in the cytoplasm, forming intracellular selenium nanospheres that are ultimately secreted into the surrounding medium. The secretion of the selenium nanospheres is accompanied by the export of a ~95 kDa protein SefA (selenium factor A). SefA has no cleavable signal peptide, suggesting that it is also exported directly for the cytoplasmic compartment. It has been suggested that SefA functions to stabilize the formation of the selenium nanospheres before secretion, possibly providing reaction sites for selenium nanosphere creation or providing a shell to prevent subsequent selenium aggregation. The present paper draws on our current knowledge of selenate respiration and selenium biomineralization in T. selenatis and other analogous systems, and extends the application of nanoparticle tracking analysis to determine the size distribution profile of the selenium nanospheres secreted.

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Yan, Xin, Qi Zhang, Xinyue Ma, Yewen Zhong, Hengni Tang e Sui Mai. "The mechanism of biomineralization: Progress in mineralization from intracellular generation to extracellular deposition". Japanese Dental Science Review 59 (dicembre 2023): 181–90. http://dx.doi.org/10.1016/j.jdsr.2023.06.005.

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Schwaner, Caroline, Sarah Farhat, John Haley, Emmanuelle Pales Espinosa e Bassem Allam. "Proteomic and Transcriptomic Responses Enable Clams to Correct the pH of Calcifying Fluids and Sustain Biomineralization in Acidified Environments". International Journal of Molecular Sciences 23, n. 24 (16 dicembre 2022): 16066. http://dx.doi.org/10.3390/ijms232416066.

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Seawater pH and carbonate saturation are predicted to decrease dramatically by the end of the century. This process, designated ocean acidification (OA), threatens economically and ecologically important marine calcifiers, including the northern quahog (Mercenaria mercenaria). While many studies have demonstrated the adverse impacts of OA on bivalves, much less is known about mechanisms of resilience and adaptive strategies. Here, we examined clam responses to OA by evaluating cellular (hemocyte activities) and molecular (high-throughput proteomics, RNASeq) changes in hemolymph and extrapallial fluid (EPF—the site of biomineralization located between the mantle and the shell) in M. mercenaria continuously exposed to acidified (pH ~7.3; pCO2 ~2700 ppm) and normal conditions (pH ~8.1; pCO2 ~600 ppm) for one year. The extracellular pH of EPF and hemolymph (~7.5) was significantly higher than that of the external acidified seawater (~7.3). Under OA conditions, granulocytes (a sub-population of hemocytes important for biomineralization) were able to increase intracellular pH (by 54% in EPF and 79% in hemolymph) and calcium content (by 56% in hemolymph). The increased pH of EPF and hemolymph from clams exposed to high pCO2 was associated with the overexpression of genes (at both the mRNA and protein levels) related to biomineralization, acid–base balance, and calcium homeostasis, suggesting that clams can use corrective mechanisms to mitigate the negative impact of OA.

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Balfourier, Alice, Nathalie Luciani, Guillaume Wang, Gerald Lelong, Ovidiu Ersen, Abdelali Khelfa, Damien Alloyeau, Florence Gazeau e Florent Carn. "Unexpected intracellular biodegradation and recrystallization of gold nanoparticles". Proceedings of the National Academy of Sciences 117, n. 1 (18 dicembre 2019): 103–13. http://dx.doi.org/10.1073/pnas.1911734116.

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Gold nanoparticles are used in an expanding spectrum of biomedical applications. However, little is known about their long-term fate in the organism as it is generally admitted that the inertness of gold nanoparticles prevents their biodegradation. In this work, the biotransformations of gold nanoparticles captured by primary fibroblasts were monitored during up to 6 mo. The combination of electron microscopy imaging and transcriptomics study reveals an unexpected 2-step process of biotransformation. First, there is the degradation of gold nanoparticles, with faster disappearance of the smallest size. This degradation is mediated by NADPH oxidase that produces highly oxidizing reactive oxygen species in the lysosome combined with a cell-protective expression of the nuclear factor, erythroid 2. Second, a gold recrystallization process generates biomineralized nanostructures consisting of 2.5-nm crystalline particles self-assembled into nanoleaves. Metallothioneins are strongly suspected to participate in buildings blocks biomineralization that self-assembles in a process that could be affected by a chelating agent. These degradation products are similar to aurosomes structures revealed 50 y ago in vivo after gold salt therapy. Overall, we bring to light steps in the lifecycle of gold nanoparticles in which cellular pathways are partially shared with ionic gold, revealing a common gold metabolism.

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Mayorova, Tatiana D. "Differentiation of Crystal Cells, Gravity-Sensing Cells in the Placozoan Trichoplax adhaerens". Journal of Marine Science and Engineering 9, n. 11 (6 novembre 2021): 1229. http://dx.doi.org/10.3390/jmse9111229.

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Trichoplax adhaerens are simple animals with no nervous system, muscles or body axis. Nevertheless, Trichoplax demonstrate complex behaviors, including responses to the direction of the gravity vector. They have only six somatic cell types, and one of them, crystal cells, has been implicated in gravity reception. Multiple crystal cells are scattered near the rim of the pancake-shaped animal; each contains a cup-shaped nucleus and an intracellular crystal, which aligns its position according to the gravity force. Little is known about the development of any cell type in Trichoplax, which, in the laboratory, propagate exclusively by binary fission. Electron and light microscopy were used to investigate the stages by which crystal cells develop their mature phenotypes and distributions. Nascent crystal cells, identified by their possession of a small crystal, were located farther from the rim than mature crystal cells, indicating that crystal cells undergo displacement during maturation. They were elongated in shape and their nucleus was rounded. The crystal develops inside a vacuole flanked by multiple mitochondria, which, perhaps, supply molecules needed for the biomineralization process underlying crystal formation. This research sheds light on the development of unique cells with internal biomineralization and poses questions for further research.

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Monteil, Caroline L., Karim Benzerara, Nicolas Menguy, Cécile C. Bidaud, Emmanuel Michot-Achdjian, Romain Bolzoni, François P. Mathon et al. "Intracellular amorphous Ca-carbonate and magnetite biomineralization by a magnetotactic bacterium affiliated to the Alphaproteobacteria". ISME Journal 15, n. 1 (24 agosto 2020): 1–18. http://dx.doi.org/10.1038/s41396-020-00747-3.

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Romero-Núñez, Araceli, Gonzalo González, Abel Moreno e Mayra Cuéllar-Cruz. "Biomineralization and biosynthesis of nanocrystalline materials and selective uptake of toxic metals controlled by five types of Candida species". CrystEngComm 21, n. 15 (2019): 2585–95. http://dx.doi.org/10.1039/c8ce02197j.

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Fischer, Anna, Manuel Schmitz, Barbara Aichmayer, Peter Fratzl e Damien Faivre. "Structural purity of magnetite nanoparticles in magnetotactic bacteria". Journal of The Royal Society Interface 8, n. 60 (19 gennaio 2011): 1011–18. http://dx.doi.org/10.1098/rsif.2010.0576.

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Magnetosome biomineralization and chain formation in magnetotactic bacteria are two processes that are highly controlled at the cellular level in order to form cellular magnetic dipoles. However, even if the magnetosome chains are well characterized, controversial results about the microstructure of magnetosomes were obtained and its possible influence in the formation of the magnetic dipole is to be specified. For the first time, the microstructure of intracellular magnetosomes was investigated using high-resolution synchrotron X-ray diffraction. Significant differences in the lattice parameter were found between intracellular magnetosomes from cultured magnetotactic bacteria and isolated ones. Through comparison with abiotic control materials of similar size, we show that this difference can be associated with different oxidation states and that the biogenic nanomagnetite is stoichiometric, i.e. structurally pure whereas isolated magnetosomes are slightly oxidized. The hierarchical structuring of the magnetosome chain thus starts with the formation of structurally pure magnetite nanoparticles that in turn might influence the magnetic property of the magnetosome chains.

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Picone, Giovanna, Concettina Cappadone, Alice Pasini, Joseph Lovecchio, Marilisa Cortesi, Giovanna Farruggia, Marco Lombardo et al. "Analysis of Intracellular Magnesium and Mineral Depositions during Osteogenic Commitment of 3D Cultured Saos2 Cells". International Journal of Molecular Sciences 21, n. 7 (30 marzo 2020): 2368. http://dx.doi.org/10.3390/ijms21072368.

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In this study, we explore the behaviour of intracellular magnesium during bone phenotype modulation in a 3D cell model built to mimic osteogenesis. In addition, we measured the amount of magnesium in the mineral depositions generated during osteogenic induction. A two-fold increase of intracellular magnesium content was found, both at three and seven days from the induction of differentiation. By X-ray microscopy, we characterized the morphology and chemical composition of the mineral depositions secreted by 3D cultured differentiated cells finding a marked co-localization of Mg with P at seven days of differentiation. This is the first experimental evidence on the presence of Mg in the mineral depositions generated during biomineralization, suggesting that Mg incorporation occurs during the bone forming process. In conclusion, this study on the one hand attests to an evident involvement of Mg in the process of cell differentiation, and, on the other hand, indicates that its multifaceted role needs further investigation.

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Tanaka, Masayoshi, Atsushi Arakaki, Sarah S. Staniland e Tadashi Matsunaga. "Simultaneously Discrete Biomineralization of Magnetite and Tellurium Nanocrystals in Magnetotactic Bacteria". Applied and Environmental Microbiology 76, n. 16 (25 giugno 2010): 5526–32. http://dx.doi.org/10.1128/aem.00589-10.

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ABSTRACT Magnetotactic bacteria synthesize intracellular magnetosomes comprising membrane-enveloped magnetite crystals within the cell which can be manipulated by a magnetic field. Here, we report the first example of tellurium uptake and crystallization within a magnetotactic bacterial strain, Magnetospirillum magneticum AMB-1. These bacteria independently crystallize tellurium and magnetite within the cell. This is also highly significant as tellurite (TeO3 2−), an oxyanion of tellurium, is harmful to both prokaryotes and eukaryotes. Additionally, due to its increasing use in high-technology products, tellurium is very precious and commercially desirable. The use of microorganisms to recover such molecules from polluted water has been considered as a promising bioremediation technique. However, cell recovery is a bottleneck in the development of this approach. Recently, using the magnetic property of magnetotactic bacteria and a cell surface modification technology, the magnetic recovery of Cd2+ adsorbed onto the cell surface was reported. Crystallization within the cell enables approximately 70 times more bioaccumulation of the pollutant per cell than cell surface adsorption, while utilizing successful recovery with a magnetic field. This fascinating dual crystallization of magnetite and tellurium by magnetotactic bacteria presents an ideal system for both bioremediation and magnetic recovery of tellurite.

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Chang, William W., Ann-Sophie Matt, Marcus Schewe, Marianne Musinszki, Sandra Grüssel, Jonas Brandenburg, David Garfield, Markus Bleich, Thomas Baukrowitz e Marian Y. Hu. "An otopetrin family proton channel promotes cellular acid efflux critical for biomineralization in a marine calcifier". Proceedings of the National Academy of Sciences 118, n. 30 (22 luglio 2021): e2101378118. http://dx.doi.org/10.1073/pnas.2101378118.

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Otopetrins comprise a family of proton-selective channels that are critically important for the mineralization of otoliths and statoconia in vertebrates but whose underlying cellular mechanisms remain largely unknown. Here, we demonstrate that otopetrins are critically involved in the calcification process by providing an exit route for protons liberated by the formation of CaCO3. Using the sea urchin larva, we examined the otopetrin ortholog otop2l, which is exclusively expressed in the calcifying primary mesenchymal cells (PMCs) that generate the calcitic larval skeleton. otop2l expression is stimulated during skeletogenesis, and knockdown of otop2l impairs spicule formation. Intracellular pH measurements demonstrated Zn2+-sensitive H+ fluxes in PMCs that regulate intracellular pH in a Na+/HCO3−-independent manner, while Otop2l knockdown reduced membrane proton permeability. Furthermore, Otop2l displays unique features, including strong activation by high extracellular pH (>8.0) and check-valve–like outwardly rectifying H+ flux properties, making it into a cellular proton extrusion machine adapted to oceanic living conditions. Our results provide evidence that otopetrin family proton channels are a central component of the cellular pH regulatory machinery in biomineralizing cells. Their ubiquitous occurrence in calcifying systems across the animal kingdom suggest a conserved physiological function by mediating pH at the site of mineralization. This important role of otopetrin family proton channels has strong implications for our view on the cellular mechanisms of biomineralization and their response to changes in oceanic pH.

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Pei, Di, Zhiming Liu, Wenjian Wu e Biru Hu. "Transcriptome analyses reveal the utilization of nitrogen sources and related metabolic mechanisms of Sporosarcina pasteurii". PLOS ONE 16, n. 2 (9 febbraio 2021): e0246818. http://dx.doi.org/10.1371/journal.pone.0246818.

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In recent years, Sporosarcina pasteurii (S. pasteurii) has become one of the most popular bacteria in microbially induced calcium carbonate precipitation (MICP). Various applications have been developed based on the efficient urease that can induce the precipitation of calcium carbonate. However, the metabolic mechanism related to biomineralization of S. pasteurii has not been clearly elucidated. The process of bacterial culture and biomineralization consumes a large amount of urea or ammonium salts, which are usually used as agricultural fertilizers, not to mention probable environmental pollutions caused by the excessive use of these raw materials. Therefore, it is urgent to reveal the mechanism of nitrogen utilization and metabolism of S. pasteurii. In this paper, we compared the growth and gene expression of S. pasteurii under three different culture conditions through transcriptome analyses. GO and KEGG analyses revealed that both ammonium and urea were direct nitrogen sources of S. pasteurii, and the bacteria could not grow normally in the absence of ammonium or urea. To the best of our knowledge, this paper is the first one to reveal the nitrogen utilization mechanism of S. pasteurii through transcriptome methods. Furthermore, the presence of ammonium might promote the synthesis of intracellular ATP and enhance the motility of the bacteria. There should be an ATP synthesis mechanism associated with urea hydrolysis catalyzed by urease in S. pasteurii.

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Han, Zuozhen, Wenwen Yu, Hui Zhao, Yanhong Zhao, Maurice Tucker e Huaxiao Yan. "The Significant Roles of Mg/Ca Ratio, Cl− and SO42− in Carbonate Mineral Precipitation by the Halophile Staphylococcus epidermis Y2". Minerals 8, n. 12 (14 dicembre 2018): 594. http://dx.doi.org/10.3390/min8120594.

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Carbonate precipitation induced by microorganisms has become a hot topic in the field of carbonate sedimentology, although the effects of magnesium on biomineral formation have rarely been studied. In experiments described here, magnesium sulfate and magnesium chloride were used to investigate the significant role played by Mg2+ on carbonate precipitation. In this study, Staphylococcus epidermidis Y2 was isolated and identified by 16S ribosomal DNA (rDNA) homology comparison and ammonia, pH, carbonic anhydrase, carbonate, and bicarbonate ions were monitored during laboratory experiments. The mineral phase, morphology, and elemental composition of precipitates were analyzed by XRD and SEM-EDS. Ultrathin slices of bacteria were analyzed by HRTEM-SAED and STEM. The results show that this bacterium releases ammonia and carbonic anhydrase to increase pH, and raise supersaturation via the large number of carbonate and bicarbonate ions that are released through carbon dioxide hydration catalyzed by carbonic anhydrase. The crystal cell density of monohydrocalcite is lower in a magnesium chloride medium, compared to one of magnesium sulfate. Crystals grow in the mode of a spiral staircase in a magnesium sulfate medium, but in a concentric circular pattern in a magnesium chloride medium. There was no obvious intracellular biomineralization taking place. The results presented here contribute to our understanding of the mechanisms of biomineralization, and to the role of Mg2+ in crystal form.

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Bonny, Sandy M., e Brian Jones. "Barite (BaSO4) biomineralization at Flybye Springs, a cold sulphur spring system in Canada's Northwest Territories". Canadian Journal of Earth Sciences 44, n. 6 (29 giugno 2007): 835–56. http://dx.doi.org/10.1139/e06-126.

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The Flybye Springs, Northwest Territories, consist of 10 active vents and numerous small seeps that discharge sulphide- and barium-rich spring waters at an average temperature 8.5 °C. Oxidation of sulphide to sulphate drives precipitation of stellate and platy barite microcrystals in the proximal flow paths. Downstream, and in vent- and tributary-fed ponds, barite is precipitated among streamer and mat forming colonies of sulphur-tolerant microbes, including Thiothrix, Beggiatoa, Thioploca, Chromatium, Oscillatoria, fungi (dominantly Penicillium), and unicellular sulphate reducing bacteria. These microbes mediate barite saturation by adjusting redox gradients and via passive adsorption of barium ions to cell surfaces and extracellular polymeric substances. Passive biomineralization produces barite laminae in floating microbial mats, nanometric coatings, and micrometric encrustations around microbial cells and filaments, and local permineralization of Thiothrix, Beggiatoa, and Oscillatoria outer cell walls. Intracellular barium enrichment and (or) metabolic sulphur oxidation may be important to "active biomineralization" that produces nanometric barite globules on the tips of fungal hyphae, barite-filled cell cavities in Beggiatoa and Thiothrix, and baritized sulphur globules. Degradation of biomineralized cells generates detrital "microfossils," including barite tunnels, layered cylinders, solid cylindrical grains and chains of barite beads. The diversity of inorganic and biomineralized barite in the Flybye Springs flow path highlights the influence of ambient chemistry, microbial metabolism, and cellular structure on barite solubility and on the taphonomy of microfossils preserved in barite.

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Reichinger, Daniela, Manuel Reithofer, Mariam Hohagen, Mirjana Drinic, Joshua Tobias, Ursula Wiedermann, Freddy Kleitz, Beatrice Jahn-Schmid e Christian F. W. Becker. "A Biomimetic, Silaffin R5-Based Antigen Delivery Platform". Pharmaceutics 15, n. 1 (29 dicembre 2022): 121. http://dx.doi.org/10.3390/pharmaceutics15010121.

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Nature offers a wide range of evolutionary optimized materials that combine unique properties with intrinsic biocompatibility and that can be exploited as biomimetic materials. The R5 and RRIL peptides employed here are derived from silaffin proteins that play a crucial role in the biomineralization of marine diatom silica shells and are also able to form silica materials in vitro. Here, we demonstrate the application of biomimetic silica particles as a vaccine delivery and adjuvant platform by linking the precipitating peptides R5 and the RRIL motif to a variety of peptide antigens. The resulting antigen-loaded silica particles combine the advantages of biomaterial-based vaccines with the proven intracellular uptake of silica particles. These particles induce NETosis in human neutrophils as well as IL-6 and TNF-α secretion in murine bone marrow-derived dendritic cells.

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Pan, Zhao, Tucker, Zhou, Jiang, Wang, Zhao, Sun, Han e Yan. "Biomineralization of Monohydrocalcite Induced by the Halophile Halomonas smyrnensis WMS‐3". Minerals 9, n. 10 (15 ottobre 2019): 632. http://dx.doi.org/10.3390/min9100632.

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The halophilic bacterium Halomonas smyrnensis from a modern salt lake used in experiments to induce biomineralization has resulted in the precipitation of monohydrocalcite and other carbonate minerals. In this study, a Halomonas smyrnensis WMS‐3 (GenBank:MH425323) strain was identified based on 16S rDNA homology comparison, and then cultured in mediums with 3% NaCl concentration to induce monohydrocalcite at different Mg/Ca molar ratios of 0, 2, 5, 7, and 9. The growth curve of WMS‐3 bacteria, pH values, NH4+ concentration, HCO3− and CO32− concentration, carbonic anhydrase (CA) activity, and the changes in Ca2+ and Mg2+ ion concentration were determined to further explore the extracellular biomineralization mechanism. Moreover, the nucleation mechanism of monohydrocalcite on extracellular polymeric substances (EPS) was analyzed through studying ultrathin slices of the WMS‐3 strain by High resolution transmission electron microscopy (HRTEM), Selected area election diffraction (SAED), Scanning transmission electron microscopy (STEM), and elemental mapping, besides this, amino acids in the EPS were also analyzed. The results show that pH increased to about 9.0 under the influence of ammonia and CA activity. The precipitation ratio (%, the ratio of the mass/volume concentration) of the Ca2+ ion was 64.32%, 62.20%, 60.22%, 59.57%, and 54.42% at Mg/Ca molar ratios of 0, 2, 5, 7, and 9, respectively, on the 21st day of the experiments, and 6.69%, 7.10%, 7.74%, 8.09% for the Mg2+ ion concentration at Mg/Ca molar ratios 2, 5, 7, and 9, respectively. The obtained minerals were calcite, Mg‐rich calcite, aragonite, and hydromagnesite, in addition to the monohydrocalcite, as identified by X-ray diffraction (XRD) analyses. Monohydrocalcite had higher crystallinity when the Mg/Ca ratio increased from 7 to 9; thus, the stability of monohydrocalcite increased, also proven by the thermogravimetry (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC) analyses. The C=O and C–O–C organic functional groups present in/on the minerals analyzed by Fourier transform infrared spectroscopy (FTIR), the various morphologies and the existence of P and S determined by scanning electron microscope-energy dispersive spectrometer (SEM‐EDS), the relatively more negative stable carbon isotope values (−16.91‰ to −17.91‰) analyzed by a carbon isotope laser spectrometer, plus the typical surface chemistry by XPS, all support the biogenesis of these mineral precipitates. Moreover, Ca2+ ions were able to enter the bacterial cell to induce intracellular biomineralization. This study is useful to understand the mechanism of biomineralization further and may provide theoretical reference concerning the formation of monohydrocalcite in nature.

34

Gorobets, Svitlana, Oksana Gorobets e Svitlana Kovalova. "Bioinformatic Analysis of the Genetic Mechanism of Biomineralization of Biogenic Magnetic Nanoparticles in Bacteria Capable of Tumor-Specific Accumulation". Innovative Biosystems and Bioengineering 6, n. 2 (5 settembre 2022): 48–55. http://dx.doi.org/10.20535/ibb.2022.6.2.260183.

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Background. Current methods of targeted cancer therapy are not always effective enough and can lead to side effects, such as an increased risk of autoimmune diseases. It is known that some bacteria are capable of specific accumulation in malignant tumors, and therefore can be used as an alternative means of targeted drug delivery. However, the genetic mechanism of tumor-specific accumulation of bacteria is not fully understood and needs to be studied in more detail. Objective. This work aims to identify, by methods of comparative genomics methods, magnetically controlled bacteria among those for which tumor-specific accumulation has already been experimentally shown. Methods. To identify magnetically controlled bacterial strains, i.e., bacteria that biomineralize biogenic magnetic nanoparticles (BMN), the method of comparative genomics was used, namely: pairwise alignment of proteomes with amino acid sequences of Mam-proteins of required for biomineralization of BMN in magnetotactic bacteria Magnetospirillum gryphiswaldense MSR-1. Sequence alignments were performed in the BLAST program of the US National Center for Biotechnology Information (NCBI). Results. The conducted bioinformatic analysis showed that strains of bacteria in which the ability to accumulate specifically in tumors has been experimentally proven are potential producers of BMN of different types. Among them there are potential producers of intracellular crystalline BMN, potential producers of intracellular amorphous BMN, and extracellular crystalline BMN Conclusions. It is expedient to use bacteria-producing BMN as gene vectors and systems of targeted drug delivery to tumors that biomineralize BMN.

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Martignier, Agathe, Montserrat Filella, Jean-Michel Jaquet, Mathieu Coster e Daniel Ariztegui. "First Observation of Unicellular Organisms Concentrating Arsenic in ACC Intracellular Inclusions in Lake Waters". Geosciences 12, n. 1 (8 gennaio 2022): 32. http://dx.doi.org/10.3390/geosciences12010032.

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In unicellular organisms, intracellular inclusions of amorphous calcium carbonate (ACC) were initially described in cyanobacteria and, later, in unicellular eukaryotes from Lake Geneva (Switzerland/France). Inclusions in unicellular eukaryotes, named micropearls, consist of hydrated ACCs, frequently enriched in Sr or Ba, and displaying internal oscillatory zonations, due to variations in the Ba:Ca or Sr:Ca ratios. An analysis of our database, consisting of 1597 micropearl analyses from Lake Geneva and 34 from Lake Titicaca (Bolivia/Peru), showed that a certain number of Sr- and Ba-enriched micropearls from these lakes contain As in amounts measurable by EDXS. A Q-mode statistical analysis confirmed the existence of five chemically distinct morpho-chemical groups of As-bearing micropearls, among which was a new category identified in Lake Geneva, where As is often associated with Mg. This new type of micropearl is possibly produced in a small (7–12 μm size) bi-flagellated organism. Micropearls from Lake Titicaca, which contain Sr, were found in an organism very similar to Tetraselmis cordiformis, which was observed earlier in Lake Geneva. Lake Titicaca micropearls contain larger As amounts, which can be explained by the high As concentration in the water of this lake. The ubiquity of this observed biomineralization process points to the need for a better understanding of the role of amorphous or crystalline calcium carbonates in As cycling in surface waters.

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Zhao, Yanyang, Huaxiao Yan, Jingxuan Zhou, Maurice E. Tucker, Mei Han, Hui Zhao, Guangzhou Mao, Yifan Zhao e Zuozhen Han. "Bio-Precipitation of Calcium and Magnesium Ions through Extracellular and Intracellular Process Induced by Bacillus Licheniformis SRB2". Minerals 9, n. 9 (30 agosto 2019): 526. http://dx.doi.org/10.3390/min9090526.

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Removal of calcium and magnesium ions through biomineralization induced by bacteria has been proven to be an effective and environmentally friendly method to improve water quality, but the process and mechanism are far from fully understood. In this study, a newly isolated probiotic Bacillus licheniformis SRB2 (GenBank: KM884945.1) was used to induce the bio-precipitation of calcium and magnesium at various Mg/Ca molar ratios (0, 6, 8, 10, and 12) in medium with 30 g L−1 sodium chloride. Due to the increasing pH and HCO3− and CO32− concentrations caused by NH3 and carbonic anhydrase, about 98% Ca2+ and 50% Mg2+ were precipitated in 12 days. The pathways of bio-precipitation include extracellular and intracellular processes. Biominerals with more negative δ13C values (−16‰ to −18‰) were formed including calcite, vaterite, monohydrocalcite, and nesquehonite with preferred orientation. The nucleation on extracellular polymeric substances was controlled by the negatively charged amino acids and organic functional groups. The intracellular amorphous inclusions containing calcium and magnesium also contributed to the bio-precipitation. This study reveals the process and mechanism of microbial desalination for the removal of calcium and magnesium, and provides some references to explain the formation of the nesquehonite and other carbonate minerals in a natural and ancient earth surface environment.

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Han, Zuozhen, Yanyang Zhao, Huaxiao Yan, Hui Zhao, Mei Han, Bin Sun, Ruirui Meng et al. "The Characterization of Intracellular and Extracellular Biomineralization Induced by Synechocystis sp. PCC6803 Cultured under Low Mg/Ca Ratios Conditions". Geomicrobiology Journal 34, n. 4 (3 ottobre 2016): 362–73. http://dx.doi.org/10.1080/01490451.2016.1197986.

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Faivre, Damien, Lars H Böttger, Berthold F Matzanke e Dirk Schüler. "Intracellular Magnetite Biomineralization in Bacteria Proceeds by a Distinct Pathway Involving Membrane-Bound Ferritin and an Iron(II) Species". Angewandte Chemie International Edition 46, n. 44 (12 novembre 2007): 8495–99. http://dx.doi.org/10.1002/anie.200700927.

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Amor, Matthieu, Vincent Busigny, Mickaël Durand-Dubief, Mickaël Tharaud, Georges Ona-Nguema, Alexandre Gélabert, Edouard Alphandéry et al. "Chemical signature of magnetotactic bacteria". Proceedings of the National Academy of Sciences 112, n. 6 (26 gennaio 2015): 1699–703. http://dx.doi.org/10.1073/pnas.1414112112.

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There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.

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Hartmann, Carolin, Martin Elsner, Reinhard Niessner e Natalia P. Ivleva. "Nondestructive Chemical Analysis of the Iron-Containing Protein Ferritin Using Raman Microspectroscopy". Applied Spectroscopy 74, n. 2 (7 febbraio 2019): 193–203. http://dx.doi.org/10.1177/0003702818823203.

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Ferritin is a ubiquitous intracellular iron storage protein of animals, plants, and bacteria. The cavity of this protein acts like a reaction chamber for natural formation and storage of nano-sized particles via biomineralization. Knowledge of the chemical composition and structure of the iron core is highly warranted in the fields of nano technologies as well as biomolecules and medicine. Here, we show that Raman microspectroscopy (RM) is a suitable nondestructive approach for an analysis of proteins containing such nano-sized iron oxides. Our approach addresses: (1) synthesis of suitable reference materials, i.e., ferrihydrite, maghemite and magnetite nanoparticles; (2) optimization of parameters for Raman spectroscopic analysis; (3) comparison of Raman spectra from ferritin with apoferritin and our reference minerals; and (4) validation of Raman analysis by X-ray diffraction and Mössbauer spectroscopy as two independent complementary approaches. Our results reveal that the iron core of natural ferritin is composed of the iron(III) hydroxide ferrihydrite (Fe2O3 ∙ 0.5 H2O).

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Lin, Wei, Joseph L. Kirschvink, Greig A. Paterson, Dennis A. Bazylinski e Yongxin Pan. "On the origin of microbial magnetoreception". National Science Review 7, n. 2 (21 maggio 2019): 472–79. http://dx.doi.org/10.1093/nsr/nwz065.

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Abstract A broad range of organisms, from prokaryotes to higher animals, have the ability to sense and utilize Earth's geomagnetic field—a behavior known as magnetoreception. Although our knowledge of the physiological mechanisms of magnetoreception has increased substantially over recent decades, the origin of this behavior remains a fundamental question in evolutionary biology. Despite this, there is growing evidence that magnetic iron mineral biosynthesis by prokaryotes may represent the earliest form of biogenic magnetic sensors on Earth. Here, we integrate new data from microbiology, geology and nanotechnology, and propose that initial biomineralization of intracellular iron nanoparticles in early life evolved as a mechanism for mitigating the toxicity of reactive oxygen species (ROS), as ultraviolet radiation and free-iron-generated ROS would have been a major environmental challenge for life on early Earth. This iron-based system could have later been co-opted as a magnetic sensor for magnetoreception in microorganisms, suggesting an origin of microbial magnetoreception as the result of the evolutionary process of exaptation.

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Mann, H., e W. S. Fyfe. "Metal uptake and Fe-, Ti-oxide biomineralization by acidophilic microorganisms in mine-waste environments, Elliot Lake, Canada". Canadian Journal of Earth Sciences 26, n. 12 (1 dicembre 1989): 2731–35. http://dx.doi.org/10.1139/e89-234.

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Acidic effluent containing enhanced concentrations of toxic heavy metals discharges from a cumulative total of 104 ha of mine-tailings waste in Canada. Communities of acidophilic microorganisms, specifically the unicellular alga Euglena sp. and bacteria, thrive in many of the hostile, low-pH effluent environments, which are otherwise devoid of life. The micro organisms concentrate aqueous dissolved metals onto cell walls and at intracellular sites, during the life cycle, and strongly bind metals during early diagenesis. A sequence is observed in which amorphous Fe and Ti concentrated at cell walls are progressively transformed to microcrystalline aggregates of goethite, ferrihydrite, maghemite, magnetite, haematite, lepidocrocite, and ilmenite. The bioprecipitated Ti- and Fe-oxides and oxyhydroxides act as scavengers for heavy metals such as Cu, Pb, Zn, Ni, Cd, and Th. Acidophilic microorganisms play a central role in the toxic-metal budget of mine-tailings waste by efficiently sequestering aqueous metals and by promoting nucleation of oxide minerals whose inorganic formation is kinetically inhibited, thereby retarding toxic-metal dispersion into the natural environment.

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Ma, Yong, Fangfang Guo, Yunpeng Zhang, Xiuyu Sun, Tong Wen e Wei Jiang. "OxyR-Like Improves Cell Hydrogen Peroxide Tolerance by Participating in Monocyte Chemotaxis and Oxidative Phosphorylation Regulation in Magnetospirillum Gryphiswaldense MSR-1". Journal of Biomedical Nanotechnology 17, n. 12 (1 dicembre 2021): 2466–76. http://dx.doi.org/10.1166/jbn.2021.3205.

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The formation of magnetosomes inside magnetotactic bacteria is a complex process strictly controlled by the intracellular metabolic regulatory system. A series of transcriptional regulators are involved in the biosynthesis of the magnetosome, including OxyR-Like protein, which is indispensable for the maturation of magnetosomes in Magnetospirillum Gryphiswaldense MSR-1. In this study, a new function of the OxyR-Like protein that helps cells resist reactive oxygen species (ROS) was identified. A comparison of expression profile data between wild-type MSR-1 and an oxyR-Like defective mutant demonstrated that seven genes encoding chemotaxis proteins were down-regulated in the latter. On the contrary, the expression levels of numerous genes encoding proteins that are critical for cellular aerobic respiration were up-regulated. Thus, OxyR-Like enhanced the resistance of cells to ROS by increasing their environmental perception and maintaining their oxidative phosphorylation at a reasonable level to avoid the excessive production of endogenous ROS. These results increase our knowledge of the OxyR-Like regulatory network and establish a relationship between the antioxidant metabolic pathway and magnetosome biomineralization in MSR-1.

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Reiprich, Sebastian, Elif Akova, Attila Aszódi e Veronika Schönitzer. "Hyaluronan Synthases’ Expression and Activity Are Induced by Fluid Shear Stress in Bone Marrow-Derived Mesenchymal Stem Cells". International Journal of Molecular Sciences 22, n. 6 (18 marzo 2021): 3123. http://dx.doi.org/10.3390/ijms22063123.

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During biomineralization, the cells generating the biominerals must be able to sense the external physical stimuli exerted by the growing mineralized tissue and change their intracellular protein composition according to these stimuli. In molluscan shell, the myosin-chitin synthases have been suggested to be the link for this communication between cells and the biomaterial. Hyaluronan synthases (HAS) belong to the same enzyme family as chitin synthases. Their product hyaluronan (HA) occurs in the bone and is supposed to have a regulatory function during bone regeneration. We hypothesize that HASes’ expression and activity are controlled by fluid-induced mechanotransduction as it is known for molluscan chitin synthases. In this study, bone marrow-derived human mesenchymal stem cells (hMSCs) were exposed to fluid shear stress of 10 Pa. The RNA transcriptome was analyzed by RNA sequencing (RNAseq). HA concentrations in the supernatants were measured by ELISA. The cellular structure of hMSCs and HAS2-overexpressing hMSCs was investigated after treatment with shear stress using confocal microscopy. Fluid shear stress upregulated the expression of genes that encode proteins belonging to the HA biosynthesis and bone mineralization pathways. The HAS activity appeared to be induced. Knowledge about the regulation mechanism governing HAS expression, trafficking, enzymatic activation and quality of the HA product in hMSCs is essential to understand the biological role of HA in the bone microenvironment.

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Raimann, Adalbert, Christine Haberler, Janina Patsch, Diana-Alexandra Ertl, Kambis Sadeghi, Michael Freilinger, Susanna Lang, Maria Schmook, Barbara Plecko e Gabriele Haeusler. "Lethal Encephalopathy in an Infant with Hypophosphatasia despite Enzyme Replacement Therapy". Hormone Research in Paediatrics 94, n. 9-10 (2021): 390–98. http://dx.doi.org/10.1159/000520341.

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Hypophosphatasia (HPP) is an inborn error of metabolism caused by loss-of-function mutations in the biomineralization-associated alkaline phosphatase gene, encoding tissue-nonspecific alkaline phosphatase (TNSALP). Symptoms include skeletal hypomineralization and extra-skeletal manifestations such as pyridoxine (B6)-responsive seizures due to impaired cerebral B6 passage. Since the introduction of enzyme replacement therapy (ERT), skeletal manifestations and B6-responsive seizures were reported to improve significantly. Nevertheless, there is an increasing evidence of B6-independent neurological manifestation of HPP including HPP-associated encephalopathy. Here, we present for the first time the brain alterations of an infant with neonatal HPP who died of neurological complications at the age of 5 months despite early initiation of ERT. CSF analysis showed normal concentrations of biogenic amines reflecting sufficient intracellular B6 availability. Postmortem histopathology revealed severe, localized affection of the cerebral cortex including cortical lesions in layers 2 and 3 in direct proximity to TNSALP-expressing neurons and hippocampal sclerosis. Our findings confirm that TNSALP deficiency may lead to a severe encephalopathy. We hypothesize that HPP-associated encephalopathy resistant to currently available ERT may develop in addition and probably independently of typical B6-responsive seizures in some patients. Prospective, controlled studies with close neurological follow-up including brain imaging are needed to identify patients at risk for severe neurological symptoms despite ERT.

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Allemand, D., É. Tambutté, JP Girard e J. Jaubert. "Organic matrix synthesis in the scleractinian coral stylophora pistillata: role in biomineralization and potential target of the organotin tributyltin". Journal of Experimental Biology 201, n. 13 (1 luglio 1998): 2001–9. http://dx.doi.org/10.1242/jeb.201.13.2001.

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The kinetics of organic matrix biosynthesis and incorporation into scleractinian coral skeleton was studied using microcolonies of Stylophora pistillata. [14C]Aspartic acid was used to label the organic matrix since this acidic amino acid can represent up to 50 mol % of organic matrix proteins. External aspartate was rapidly incorporated into tissue protein without any detectable lag phase, suggesting either a small intracellular pool of aspartic acid or a pool with a fast turn-over rate. The incorporation of 14C-labelled macromolecules into the skeleton was linear over time, after an initial delay of 20 min. Rates of calcification, measured by the incorporation of 45Ca into the skeleton, and of organic matrix biosynthesis and incorporation into the skeleton were constant. Inhibition of calcification by the Ca2+ channel inhibitor verapamil reduced the incorporation of organic matrix proteins into the skeleton. Similarly, organic matrix incorporation into the skeleton, but not protein synthesis for incorporation into the tissue compartment, was dependent on the state of polymerization of both actin and tubulin, as shown by the sensitivity of this process to cytochalasin B and colchicin. These drugs may inhibit exocytosis of organic matrix proteins into the subcalicoblastic space. Finally, inhibition of protein synthesis by emetin or cycloheximide and inhibition of N-glycosylation by tunicamycin reduced both the incorporation of macromolecules into the skeleton and the rate of calcification. This suggests that organic matrix biosynthesis and its migration towards the site of calcification may be a prerequisite step in the calcification process. On the basis of these results, we investigated the effects of tributyltin (TBT), a component of antifouling painting known to interfere with biomineralization processes. Our results have shown that this xenobiotic significantly inhibits protein synthesis and the subsequent incorporation of protein into coral skeleton. This effect was correlated with a reduction in the rate of calcification. Protein synthesis was shown to be the parameter most sensitive to TBT (IC50=0.2 micromol l-1), followed by aspartic acid uptake by coral tissue (IC50=0.6 micromol l-1), skeletogenesis (IC50=3 micromol l-1) and Ca2+ uptake by coral tissue (IC50=20 micromol l-1). These results suggest that the mode of action of TBT on calcification may be the inhibition of organic matrix biosynthesis.

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Hollergschwandtner, Elena, Thomas Schwaha, Josef Neumüller, Ulrich Kaindl, Daniela Gruber, Margret Eckhard, Michael Stöger-Pollach e Siegfried Reipert. "Novel mesostructured inclusions in the epidermal lining of Artemia franciscana ovisacs show optical activity". PeerJ 5 (27 ottobre 2017): e3923. http://dx.doi.org/10.7717/peerj.3923.

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Background Biomineralization, e.g., in sea urchins or mollusks, includes the assembly of mesoscopic superstructures from inorganic crystalline components and biopolymers. The resulting mesocrystals inspire biophysicists and material scientists alike, because of their extraordinary physical properties. Current efforts to replicate mesocrystal synthesis in vitro require understanding the principles of their self-assembly in vivo. One question, not addressed so far, is whether intracellular crystals of proteins can assemble with biopolymers into functional mesocrystal-like structures. During our electron microscopy studies into Artemia franciscana (Crustacea: Branchiopoda), we found initial evidence of such proteinaceous mesostructures. Results EM preparations with high-pressure freezing and accelerated freeze substitution revealed an extraordinary intracellular source of mesostructured inclusions in both the cyto-and nucleoplasm of the epidermal lining of ovisacs of A. franciscana. Confocal reflection microscopy not only confirmed our finding; it also revealed reflective, light dispersing activity of these flake-like structures, their positioning and orientation with respect to the ovisac inside. Both the striation of alternating electron dense and electron-lucent components and the sharp edges of the flakes indicate self-assembly of material of yet unknown origin under supposed participation of crystallization. However, selected area electron diffraction could not verify the status of crystallization. Energy dispersive X-ray analysis measured a marked increase in nitrogen within the flake-like inclusion, and the almost complete absence of elements that are typically involved in inorganic crystallization. This rise in nitrogen could possibility be related to higher package density of proteins, achieved by mesostructure assembly. Conclusions The ovisac lining of A. franciscana is endowed with numerous mesostructured inclusions that have not been previously reported. We hypothesize that their self-assembly was from proteinaceous polycrystalline units and carbohydrates. These mesostructured flakes displayed active optical properties, as an umbrella-like, reflective cover of the ovisac, which suggests a functional role in the reproduction of A. franciscana. In turn, studies into ovisac mesostructured inclusions could help to optimizing rearing Artemia as feed for fish farming. We propose Artemia ovisacs as an in vivo model system for studying mesostructure formation.

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Xu, Hengchao, Xiaotong Peng, Shijie Bai, Kaiwen Ta, Shouye Yang, Shuangquan Liu, Ho Bin Jang e Zixiao Guo. "Precipitation of calcium carbonate mineral induced by viral lysis of cyanobacteria: evidence from laboratory experiments". Biogeosciences 16, n. 4 (28 febbraio 2019): 949–60. http://dx.doi.org/10.5194/bg-16-949-2019.

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Abstract. Viruses have been acknowledged as being important components of the marine system for the past 2 decades, but their role in the functioning of the geochemical cycle has not been thoroughly elucidated to date. Virus-induced rupturing of cyanobacteria is theoretically capable of releasing intracellular bicarbonate and inducing the homogeneous nucleation of calcium carbonate; however, experiment-based support for virus-induced calcification is lacking. In this laboratory study, both water carbonate chemistry and precipitates were monitored during the viral infection and lysis of host cells. Our results show that viral lysis of cyanobacteria can influence the carbonate equilibrium system remarkably and promotes the formation and precipitation of carbonate minerals. Amorphous calcium carbonate (ACC) and aragonite were evident in the lysate, compared with the Mg(OH)2 (brucite in this paper) precipitate in noninfected cultures, implying that a different precipitation process had occurred. Based on the carbonate chemistry change and microstructure of the precipitation, we propose that viral lysis of cyanobacteria can construct a calcification environment where carbonate is the dominant inorganic carbon species. Numerous virus particles available in lysate may coprecipitate with the calcium carbonate. The experimental results presented in this study demonstrate both the pathway and the outcome with respect to how viruses influence the mineralization of carbonate minerals. It is suggested that viral calcification offers new perspectives on mechanisms of CaCO3 biomineralization and may play a crucial role within the Earth system.

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Richter, Michael, Michael Kube, Dennis A. Bazylinski, Thierry Lombardot, Frank Oliver Glöckner, Richard Reinhardt e Dirk Schüler. "Comparative Genome Analysis of Four Magnetotactic Bacteria Reveals a Complex Set of Group-Specific Genes Implicated in Magnetosome Biomineralization and Function". Journal of Bacteriology 189, n. 13 (20 aprile 2007): 4899–910. http://dx.doi.org/10.1128/jb.00119-07.

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ABSTRACT Magnetotactic bacteria (MTB) are a heterogeneous group of aquatic prokaryotes with a unique intracellular organelle, the magnetosome, which orients the cell along magnetic field lines. Magnetotaxis is a complex phenotype, which depends on the coordinate synthesis of magnetosomes and the ability to swim and orient along the direction caused by the interaction with the Earth's magnetic field. Although a number of putative magnetotaxis genes were recently identified within a conserved genomic magnetosome island (MAI) of several MTB, their functions have remained mostly unknown, and it was speculated that additional genes located outside the MAI might be involved in magnetosome formation and magnetotaxis. In order to identify genes specifically associated with the magnetotactic phenotype, we conducted comparisons between four sequenced magnetotactic Alphaproteobacteria including the nearly complete genome of Magnetospirillum gryphiswaldense strain MSR-1, the complete genome of Magnetospirillum magneticum strain AMB-1, the complete genome of the magnetic coccus MC-1, and the comparative-ready preliminary genome assembly of Magnetospirillum magnetotacticum strain MS-1 against an in-house database comprising 426 complete bacterial and archaeal genome sequences. A magnetobacterial core genome of about 891 genes was found shared by all four MTB. In addition to a set of approximately 152 genus-specific genes shared by the three Magnetospirillum strains, we identified 28 genes as group specific, i.e., which occur in all four analyzed MTB but exhibit no (MTB-specific genes) or only remote (MTB-related genes) similarity to any genes from nonmagnetotactic organisms and which besides various novel genes include nearly all mam and mms genes previously shown to control magnetosome formation. The MTB-specific and MTB-related genes to a large extent display synteny, partially encode previously unrecognized magnetosome membrane proteins, and are either located within (18 genes) or outside (10 genes) the MAI of M. gryphiswaldense. These genes, which represent less than 1% of the 4,268 open reading frames of the MSR-1 genome, as yet are mostly of unknown functions but are likely to be specifically involved in magnetotaxis and, thus, represent prime targets for future experimental analysis.

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Arivalagan, Jaison, Amudha Ganapathy, Kalimuthu Kalishwaralal, Yinghua Chen e Anne George. "Insights into the Structure and Function of TRIP-1, a Newly Identified Member in Calcified Tissues". Biomolecules 13, n. 3 (22 febbraio 2023): 412. http://dx.doi.org/10.3390/biom13030412.

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Eukaryotic initiation factor subunit I (EIF3i), also called as p36 or TRIP-1, is a component of the translation initiation complex and acts as a modulator of TGF-β signaling. We demonstrated earlier that this intracellular protein is not only exported to the extracellular matrix via exosomes but also binds calcium phosphate and promotes hydroxyapatite nucleation. To assess other functional roles of TRIP-1, we first examined their phylogeny and showed that it is highly conserved in eukaryotes. Comparing human EIF3i sequence with that of 63 other eukaryotic species showed that more than 50% of its sequence is conserved, suggesting the preservation of its important functional role (translation initiation) during evolution. TRIP-1 contains WD40 domains and predicting its function based on this structural motif is difficult as it is present in a vast array of proteins with a wide variety of functions. Therefore, bioinformatics analysis was performed to identify putative regulatory functions for TRIP-1 by examining the structural domains and post-translational modifications and establishing an interactive network using known interacting partners such as type I collagen. Insight into the function of TRIP-1 was also determined by examining structurally similar proteins such as Wdr5 and GPSß, which contain a ß-propeller structure which has been implicated in the calcification process. Further, proteomic analysis of matrix vesicles isolated from TRIP-1-overexpressing preosteoblastic MC3T3-E1 cells demonstrated the expression of several key biomineralization-related proteins, thereby confirming its role in the calcification process. Finally, we demonstrated that the proteomic signature in TRIP1-OE MVs facilitated osteogenic differentiation of stem cells. Overall, we demonstrated by bioinformatics that TRIP-1 has a unique structure and proteomic analysis suggested that the unique osteogenic cargo within the matrix vesicles facilitates matrix mineralization.

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