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Silicate, cell wall

David H Jewson, David M Harwood
The earliest known diatom fossils with well-preserved siliceous frustules are from Lower Cretaceous neritic marine deposits in Antarctica. In this study, we analyzed the cell wall structure to establish whether their cell and life cycles were similar to modern forms. At least two filamentous species (Basilicostephanus ornatus and Archepyrgus melosiroides) had girdle band structures that functioned during cell division in a similar way to present day Aulacoseira species. Also, size analyses of cell diameter indicated that the cyclic process of size decline and size restoration used to time modern diatom life cycles was present in five species from the Lower Cretaceous (B...
February 7, 2017: Journal of Phycology
Chen Yang, Xiaoya Wang, Bing Ma, Haibo Zhu, Zhiguang Huan, Nan Ma, Chengtie Wu, Jiang Chang
Silicate bioactive materials have received significant attention for application in bone regeneration due to their excellent physicochemical properties and outstanding osteogenic bioactivity, and different methods have been developed to prepare porous silicate bioactive ceramics scaffolds for bone tissue engineering applications. Among all these methods, 3D-printing technique is obviously the most efficient way to control the porous structure. However, 3D printed bioceramic porous scaffolds need high temperature sintering which will cause volume shrinkage and reduce the controllability of the pore structure accuracy...
January 24, 2017: ACS Applied Materials & Interfaces
Huanping Lu, Zhian Li, Jingtao Wu, Yong Shen, Yingwen Li, Bi Zou, Yetao Tang, Ping Zhuang
A pot experiment was conducted to investigate the effects of calcium silicate (CS) on the subcellular distribution and chemical forms of cadmium (Cd) in grain amaranths (Amaranthus hypochondriacus L. Cv. 'K112') grown in a Cd contaminated soil. Results showed that the dry weight and the photosynthetic pigments contents in grain amaranths increased significantly with the increasing doses of CS treatments, with the highest value found for the treatment of CS3 (1.65 g/kg). Compared with the control, application of CS4 (3...
January 11, 2017: Scientific Reports
Janine Kaden, Stephan I Brückner, Susanne Machill, Christoph Krafft, Andreas Pöppl, Eike Brunner
Iron incorporation into diatom biosilica was investigated for the species Stephanopyxis turris. It is known that several "foreign" elements (e.g., germanium, titanium, aluminum, zinc, iron) can be incorporated into the siliceous cell walls of diatoms in addition to silicon dioxide (SiO2). In order to examine the amount and form of iron incorporation, the iron content in the growth medium was varied during cultivation. Fe:Si ratios of isolated cell walls were measured by ICP-OES. SEM studies were performed to examine of a possible influence of excess iron during diatom growth upon cell wall formation...
February 2017: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
Yuka Shirokawa, Masakazu Shimada
In cytoplasmic inheritance, structural states of a parent cell could be transmitted to offspring cells via two mechanisms. The first is referred to as the hangover of parent structure, where the structure itself remains and faithfully transmits within offspring cells; the second is structural inheritance, wherein the parent structure functions as a template for development of new offspring structure. We estimated to what extent the parent structure affects the development of offspring structure by structural inheritance, using a clone of the diatom Cyclotella meneghiniana The cell has two siliceous valves (a cell wall part at both cell poles): one is inherited from the parent and the other is newly formed...
November 16, 2016: Proceedings. Biological Sciences
Dimitrios Tziafas, Konstantinos Kodonas, Christos Gogos, Christina Tziafa, Seraphim Papadimitriou
OBJECTIVE: The present study aims to investigate whether reparative dentinogenesis could be guided at central pulpal sites or at a distance from the amputated pulp of miniature pig teeth, by using set calcium silicate-based carriers containing human recombinant bioactive molecules. DESIGN: Pulp exposures were performed in 72 permanent teeth of 4 healthy miniature swine. The teeth were capped with pre-manufactured implants of set calcium silicate-based material containing BMP-7, TGFβ1 or WnT-1, for 3 weeks...
January 2017: Archives of Oral Biology
Santosh Kumar, Yonat Milstein, Yaniv Brami, Michael Elbaum, Rivka Elbaum
Grasses take up silicic acid from soil and deposit it in their leaves as solid silica. This mineral, comprising 1-10% of the grass dry weight, improves plants' tolerance to various stresses. The mechanisms promoting stress tolerance are mostly unknown, and even the mineralization process is poorly understood. To study leaf mineralization in sorghum (Sorghum bicolor), we followed silica deposition in epidermal silica cells by in situ charring and air-scanning electron microscopy. Our findings were correlated to the viability of silica cells tested by fluorescein diacetate staining...
January 2017: New Phytologist
A Nazmi, R Hauck, A Davis, M Hildebrand, L B Corbeil, R A Gallardo
Diatoms are single cell eukaryotic microalgae; their surface possesses a porous nanostructured silica cell wall or frustule. Diatomaceous earth (DE) or diatomite is a natural siliceous sediment of diatoms. Since silica has been proved to have adjuvant capabilities, we propose that diatoms and DE may provide an inexpensive and abundant source of adjuvant readily available to use in livestock vaccines.In a first experiment, the safety of diatoms used as an adjuvant for in-ovo vaccination was investigated. In a second experiment, we assessed the humoral immune response after one in-ovo vaccination with inactivated Newcastle Disease Virus (NDV) and DE as adjuvant followed by 2 subcutaneous boosters on d 21 and 29 of age...
July 18, 2016: Poultry Science
Colleen A Durkin, Julie A Koester, Sara J Bender, E Virginia Armbrust
Diatoms are highly productive single-celled algae that form an intricately patterned silica cell wall after every cell division. They take up and utilize silicic acid from seawater via silicon transporter (SIT) proteins. This study examined the evolution of the SIT gene family to identify potential genetic adaptations that enable diatoms to thrive in the modern ocean. By searching for sequence homologs in available databases, the diversity of organisms found to encode SITs increased substantially and included all major diatom lineages and other algal protists...
October 2016: Journal of Phycology
Michael J Knight, Laura Senior, Bethany Nancolas, Sarah Ratcliffe, Paul Curnow
Diatoms are an important group of eukaryotic algae with a curious evolutionary innovation: they sheath themselves in a cell wall made largely of silica. The cellular machinery responsible for silicification includes a family of membrane permeases that recognize and actively transport the soluble precursor of biosilica, silicic acid. However, the molecular basis of silicic acid transport remains obscure. Here, we identify experimentally tractable diatom silicic acid transporter (SIT) homologues and study their structure and function in vitro, enabled by the development of a new fluorescence method for studying substrate transport kinetics...
2016: Nature Communications
Maike Joester, Stephan Seifert, Franziska Emmerling, Janina Kneipp
The process of silicification in plants and the biochemical effects of silica in plant tissues are largely unknown. To study the molecular changes occurring in growing cells that are exposed to higher than normal concentration of silicic acid, Raman spectra of germinating pollen grains of three species (Pinus nigra, Picea omorika, and Camellia japonica) were analyzed in a multivariate classification approach that takes into account the variation of biochemical composition due to species, plant tissue structure, and germination condition...
May 13, 2016: Journal of Biophotonics
Kazumasa Yamada, Chikako Nagasato, Taizo Motomura, Mutsuo Ichinomiya, Akira Kuwata, Mitsunobu Kamiya, Kaori Ohki, Shinya Yoshikawa
The parmalean algae possess a siliceous wall and represent the sister lineage of diatoms; they are thought to be a key group for understanding the evolution of diatoms. Diatoms possess well-characterized and unique mitotic structures, but the mitotic apparatus of Parmales is still unknown. We observed the microtubule (MT) array during interphase and mitosis in Triparma laevis using TEM. The interphase cells had four or five centrioles (∼80 nm in length), from which MTs emanated toward the cytoplasm. In prophase, the bundle of MTs arose at an extranuclear site...
January 2017: Protoplasma
Karen Grace V Bondoc, Jan Heuschele, Jeroen Gillard, Wim Vyverman, Georg Pohnert
Diatoms are highly abundant unicellular algae that often dominate pelagic as well as benthic primary production in the oceans and inland waters. Being strictly dependent on silica to build their biomineralized cell walls, marine diatoms precipitate 240 × 10(12) mol Si per year, which makes them the major sink in the global Si cycle. Dissolved silicic acid (dSi) availability frequently limits diatom productivity and influences species composition of communities. We show that benthic diatoms selectively perceive and behaviourally react to gradients of dSi...
2016: Nature Communications
Heather M McNair, Mark A Brzezinski, Jeffrey W Krause
Diatoms require silicic acid to construct ornately detailed cell walls called frustules. The growth and geographic distribution of diatoms is often controlled by the availability of silicic acid. Analytical methods exist to assess diatom community biogenic silica (bSiO2) production, but partitioning production among taxa has been largely qualitative. We present a method for the quantitative analysis of taxa-specific silica production through labeling diatoms with the fluorescent dye PDMPO [2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole]...
October 1, 2015: Limnology and Oceanography, Methods
Rohinee N Paranjpye, William B Nilsson, Martin Liermann, Elizabeth D Hilborn, Barbara J George, Quanlin Li, Brian D Bill, Vera L Trainer, Mark S Strom, Paul A Sandifer
Populations of Vibrio parahaemolyticus in the environment can be influenced by numerous factors. We assessed the correlation of total (tl+) and potentially virulent (tdh+) V. parahaemolyticus in water with three harmful algal bloom (HAB) genera (Pseudo-nitzschia, Alexandrium and Dinophysis), the abundance of diatoms and dinoflagellates, chlorophyll-a and temperature, salinity and macronutrients at five sites in Washington State from 2008-2009. The variability in V. parahaemolyticus density was explained predominantly by strong seasonal trends where maximum densities occurred in June, 2 months prior to the highest seasonal water temperature...
December 2015: FEMS Microbiology Ecology
Vijaya K R Vulavala, Rivka Elbaum, Uri Yermiyahu, Edna Fogelman, Akhilesh Kumar, Idit Ginzberg
A silicon transporter homolog was upregulated by Si fertilization and drought in potato roots and leaves. High Si in tuber skin resulted in anatomical and compositional changes suggesting delayed skin maturation. Silicon (Si) fertilization has beneficial effects on plant resistance to biotic and abiotic stresses. Potatoes, low Si accumulators, are susceptible to yield loss due to suboptimal growth conditions; thus Si fertilization may contribute to crop improvement. The effect of Si fertilization on transcript levels of putative transporters, Si uptake and tuber quality was studied in potatoes grown in a glasshouse and fertilized with sodium silicate, under normal and drought-stress conditions...
January 2016: Planta
Peter Irwin, Ly Nguyen, Yiping He, George Paoli, Andrew Gehring, Chin-Yi Chen
BACKGROUND: The disruption of the bacterial cell wall plays an important part in achieving quantitative extraction of DNA from Eubacteria essential for accurate analyses of genetic material recovered from environmental samples. RESULTS: In this work we have tested a dozen commercial bacterial genomic DNA extraction methodologies on an average of 7.70 × 10(6) (±9.05%), 4.77 × 10(8) (±31.0%), and 5.93 × 10(8) (±4.69%) colony forming units (CFU) associated with 3 cultures (n = 3) each of Brochothrix thermosphacta (Bt; Gram-positive), Shigella sonnei (Ss; Gram-negative), and Escherichia coli O79 (Ec; Gram-negative)...
2014: BMC Microbiology
Jun Zhang, Surajit Karmakar, Meihua Yu, Neena Mitter, Jin Zou, Chengzhong Yu
C. Yu and co-workers demonstrate silica vesicles with fine control over the entrance size in the siliceous walls (<3.9-34 nm). On page 5068, the entrance size is shown to be crucial for the loading and releasing of biomolecules. Silica vesicles with an optimal entrance size exhibit high loading capacity, sustained release, and superior delivery efficiency of therapeutical proteins into cells, showing promising potential for biological and biomedical applications.
December 2014: Small
Natsumi Kido, Ryusuke Yokoyama, Tsuyoshi Yamamoto, Jun Furukawa, Hiroaki Iwai, Shinobu Satoh, Kazuhiko Nishitani
Poales [represented by rice (Oryza sativa L.)] in angiosperms and Equisetum (horsetails) in Pteridophytes are two major groups of heavy silicon (Si) accumulators. In rice, Si is polymerized preferentially in the epidermal cell wall, forming Si-cuticle double layers and Si-cellulose double layers beneath the cuticle. This Si layer is thought to exert various beneficial effects on the growth and development of land plants. Although the recent discovery of the influx and efflux transporters of silicic acid has shed some light on the molecular mechanisms of Si uptake and transport in rice, the mechanism underlying the final incorporation of polymerized Si into the cell wall remains elusive...
February 2015: Plant & Cell Physiology
Roshan P Shrestha, Mark Hildebrand
The utilization of silicon by diatoms has both global and small-scale implications, from oceanic primary productivity to nanotechnological applications of their silica cell walls. The sensing and transport of silicic acid are key aspects of understanding diatom silicon utilization. At low silicic acid concentrations (<30 μM), transport mainly occurs through silicic acid transport proteins (SITs), and at higher concentrations it occurs through diffusion. Previous analyses of the SITs were done either in heterologous systems or without a distinction between individual SITs...
January 2015: Eukaryotic Cell
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