To see the other types of publications on this topic, follow the link: Nostoc.
Dissertations / Theses on the topic 'Nostoc'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Nostoc.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ehling-Schulz, Monika. "Physiological and protein-biochemical analysis of UV-A and UV-B tolerance of the terrestrial cyanobacterium Nostoc commune." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960206582.
Full text
2
Lozada, Borjas Carlos Martin. "Estudio comparativo de la actividad antioxidante de los polisacáridos extracelulares de Nostoc sphaericum y Nostoc commune." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/7587.
Full textAbstract:
Publicación a texto completo no autorizada por el autorCompara la actividad antioxidante in vitro de los polisacáridos extracelulares de las cianobacterias Nostoc sphaericum y Nostoc commune recolectados en la laguna de Patococha, región Ancash; así como, la comparación de sus actividades. El tamizaje fitoquímico se realizó mediante los reactivos de Molish, antrona, ninhidrina, tricloruro férrico, gelatina, Shinoda, Fehling, Lieberman Bouchardat, Dragendorff, Mayer, Rosenheim, hidroxilamina, vainillin sulfúrico, Bertrand, Sonenheim y Bornträger. La actividad antioxidante de los polisacáridos se determinó por neutralización de los radicales: 1,1-difenil-2-picril-hidrazilo (DPPH) y ácido 2,2’-azinobis (3- etilbenzotiazolin)-6-sulfónico (ABTS). La comparación de las actividades antioxidantes de los polisacáridos extracelulares se realizó mediante análisis estadísticos ANOVA y T-student, utilizando el paquete IBM SPSS 24.0. En los extractos se evidenciaron presencia de carbohidratos, azúcares reductores, esteroides o triterpenos, alcaloides, catequinas y antocianinas, saponinas y antraquinonas en ambas cianobacterias. En la evaluación de la actividad antioxidante, los polisacáridos extracelulares de Nostoc sphaericum presentaron un IC50=2,068 mg/mL y un IC50=4,398 mg/mL en el ensayo de DPPH y ABTS, respectivamente, mientras que los polisacáridos extracelulares de Nostoc commune presentaron un IC50=2,482 mg/mL y un IC50=17,837 mg/mL en el ensayo de DPPH y ABTS, respectivamente. El análisis estadístico reveló que no existe diferencia significativa entre actividad antioxidante de polisacáridos extraceulares del Nostoc sphaericum y Nostoc commune medidos por el método de DPPH; sin embargo, sí existe diferencia significativa entre actividad antioxidante de los polisacáridos extracelulares de dichas especies medido por el método de ABTS. Se concluye que los polisacáridos extracelulares de Nostoc sphaericum presentaron una mayor actividad antioxidante que los polisacáridos extracelulares de Nostoc commune.
Tesis
3
Waters, Margaret Fiona. "Enzymes of RNA metabolism in Nostoc sp. MAC." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329409.
Full text
4
Jordan, Brian Robert. "Carbohydrate-Interacting Proteins from Two Nostoc (Cyanobacteria) Species." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/11177.
Full textAbstract:
Cyanobacteria of the Nostoc genus are known for the thick, mucilaginous carbohydrate coatings that they produce. In this work, two examples of cyanobacterial glycobiology are considered, each of which involves a cyanobacterium of the Nostoc genus.
The first portion of this work details attempts to obtain amino acid sequence information from the enzymes (glycosyltransferases) that are responsible for producing the extracellular polysaccharide (EPS) of Nostoc commune DRH1, ultimately to allow the transfer of this capacity to another organism. Two artificial substrates were synthesized for use in a capillary electrophoresis-based enzyme assay, which was used to look for glycosyltransferase activity in Nostoc commune DRH1 cell extracts. Glucuronosyltransferase activity was detected in association with Nostoc commune membrane material. The active enzyme displayed a divalent cation metal dependence (Mg+2) that is typical of glycosyltransferase enzymes purified from other organisms. Because the enzyme responsible for this activity held the potential to be EPS-related, its purification was attempted.
The capillary electrophoresis-based enzyme assay and a 32P-labeled affinity tag were utilized to follow the glucuronosyltransferase enzyme through successive purification steps. The active enzyme was extracted from Nostoc commune membrane material using Triton X-100, and then purified by anion exchange chromatography. The active detergent extract was extremely unstable, and consequently, other purification techniques tested were unsuccessful in enriching activity. Affinity-labeling experiments indicated that the active enzyme was forming protein aggregates during these procedures, which were not amenable to in-gel protease digestion and peptide analysis by tandem mass spectrometry.
The second portion of this work describes an investigation of an Anabaena (Nostoc) PCC 7120 soluble cell extract. Upon separation by sodium dodecyl sulfate ¡V polyacrylamide gel electrophoresis (SDS-PAGE) and subsequent periodic acid-Schiff (PAS) staining of the resulting gel, the components of this cellular fraction produce a ladder-like pattern, which suggests that the extract may contain glycosylated protein. Analyses of several samples that were taken from within the PAS-staining region of such a gel revealed surface layer homology (SLH) domain-containing proteins, likely candidates to be covalently attached to or non-covalently interacting with carbohydrate.
Various protein sequence analyses indicated that the detected SLH domain containing proteins belong to a family of (putative) cyanobacterial porins. Proteins in this family possess features that include a N-terminal signal sequence, a single SLH domain motif, followed by a coiled-coil region, and a C-terminal region that is homologous to the b-barrel-forming region of bacterial porins. All of these features were identified in the detected Anabaena (Nostoc) PCC 7120 SLH domain-containing proteins. Smith degradation was performed on a sample that was electroeluted from the PAS-staining region of a preparative-scale SDS-PAGE gel of the soluble cell extract. Subsequent analyses of the resulting sample by SDS-PAGE and mass spectrometry indicated that at least two SLH domain-containing proteins, encoded by all4499 and alr4550, were non-covalently interacting with the PAS-staining material. Following degradation, the PAS-staining material was still of sufficient size to detected by gel electrophoresis, and it continued to migrate in the absence of an interacting protein component. Protease digestion of a similarly prepared sample, and then subsequent analysis by SDS-PAGE and mass spectrometry, revealed that the region between amino acid residues #504 and #536, in the protein encoded by the alr4550 open reading frame, was interacting with the PAS-staining material. Monosaccharide composition analyses of this material revealed more carbohydrate constituents than are found in cyanobacterial primary (peptidoglycan) cell wall polymer alone, indicating that it contained a significant secondary cell wall polymer component as well.Ph. D.
5
Lennihan, Robert. "Ecology of Nostoc in a high arctic oasis /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/5184.
Full text
6
Špakaitė, Ina. "Morphology, ecology and phylogeny of cyanobacteria belonging to genera Nostoc and Desmonostoc in Lithuania." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140915_151715-83237.
Full textAbstract:
The aim of the study was to investigate the morphology, ecology and phylogeny of cyanobacteria belonging to genera Nostoc and Desmonostoc in Lithuania. The detailed research of freshwater and terrestrial Nostoc and Desmonostoc species provided new data on taxonomy, biology and ecology of these cyanobacteria and the overall diversity of algae in Lithuania. 20 Nostoc species and two intraspecific taxa, and 18 taxa to the Nostoc genus level were identified. Twelve Nostoc species and intraspecific taxa, Desmonostoc genus including two taxa were recorded for the first time in Lithuania. A check list was compiled of all identified species with original morphological and ecological data as well as pictures. An applied research by different types of Nostoc and Desmonostoc species samples was valuable in morphological analysis – suitability for identification and stability of diagnostic morphological features in species was identified. The highest diversity of Nostoc and Desmonostoc species were recorded in lentic ecosystems and 14 species were found in terrestrial habitats. A wide genetic and morphological diversity of Nostoc and Desmonostoc species was identified while performing fingerprint TGGE and morphological analyses of cyanobacterial natural populations. The morphological and phylogenetic analyses of Nostoc and Desmonostoc strains showed morphological and phylogenetic heterogenity of Nostoc species and differences of the same types between Desmonostoc and Nostoc species.Darbo tikslas – atlikti Lietuvos Nostoc ir Desmonostoc genčių melsvabakterių morfologijos, ekologijos ir filogenijos tyrimus. Pirmą kartą Lietuvoje atlikti išsamūs gėlųjų vandenų ir sausumos Nostoc ir Desmonostoc genčių melsvabakterių tyrimai papildo žinias apie dumblių rūšių įvairovę Lietuvoje bei suteikia naujos informacijos apie šių melsvabakterių taksonomiją, biologiją ir ekologiją. Identifikuota 22 Nostoc genties rūšys ir vidurūšiniai taksonai, 18 Nostoc taksonų identifikuota iki genties rango. Pirmą kartą Lietuvoje identifikuota 12 Nostoc genties rūšių ir vidurūšinių taksonų, dvi Desmonostoc genties rūšys. Rūšių konspekte pateikiami originalūs rūšių aprašymai su nuotraukomis ir ekologijos duomenys. Nostoc ir Desmonostoc genčių rūšių morfologinėje analizėje taikytas skirtingo tipo pavyzdžių tyrimas pasitvirtino – įvertintas rūšių diagnostinių morfologinių požymių stabilumas ir identifikacinis tinkamumas. Didžiausia Nostoc ir Desmonostoc genčių rūšių įvairovė identifikuota lentinėse ekosistemose, o sausumos buveinėse konstatuota 14 rūšių. Melsvabakterių gamtinių populiacijų molekulinių žymenų TGGE ir morfologinės analizių metu nustatyta gana didelė Nostoc ir Desmonostoc genčių rūšių genetinė ir morfologinė įvairovė. Nostoc ir Desmonostoc genčių padermių morfologinė ir filogenetinė analizės atskleidė Nostoc genties rūšių morfologinį ir filogenetinį heterogeniškumą bei Desmonostoc ir Nostoc genčių rūšių tokių tipų tarpusavio skirtumus.
7
Lichtl, Rixa Regina. "The hydrogen production capability of free-living Nostoc filagelliforme." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362742.
Full text
8
Ow, Saw Yen. "High throughput quantitative proteomics development : A tool to achieve system-wide understanding of N2 fixing cyanobacteria nostoc Sp.PCC 7120 and nostoc punctiforme ATCC 29133." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500186.
Full text
9
Wright, Deborah J. "Molecular Biology of Desiccation Tolerance in the Cyanobacterium Nostoc commune." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9714.
Full textAbstract:
The molecular biology of desiccation tolerance was investigated in the cyanobacteria with emphasis on Nostoc commune. Analysis of DNA from 41 samples of desiccated Nostoc spp. of varied age and global distribution led to the amplification of 43 independent tRNALEU(UAA) group 1 intron sequences. Phylogenetic analysis of the entire data set made it possible to define the form species Nostoc commune.
The synthase (spsA) and phosphatase (sppA) genes required for the synthesis of sucrose were isolated from cyanobacterium Synechocystis sp. strain PCC 6803 and overexpressed in E. coli in two different vector constructions. Transformants had a marked increased capacity for desiccation tolerance. Sucrose synthesis was confirmed through thin layer chromatography (TLC) analysis of cell extracts from transformants.
Long-term stability of DNA in desiccated Nostoc samples was demonstrated by the ability to amplify selected gene loci from samples stored dry for decades. Successful amplification in some samples was possible only after treatment with phenacylthiazolium bromide, a reagent that disrupts covalent cross-links; indicating that the DNA was modified by cross-links that occurred between reducing sugars and the primary amines on the DNA.
Abundant superoxide dismutase was released following rehydration of desiccated field material N. commune CHEN after 13 years in the dry state. sodF mRNA was present in the dry material but was turned over within 15 min of rehydration. mRNA levels then rose and appeared to reach steady state levels after 3 hours and remained abundant after 24 hours of rehydration.Master of Science
10
Cardona, Tanai. "The heterocysts of nostoc punctiforme from proteomics to energy transfer /." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-108413.
Full text
11
Heekin, Jonathan. "THE EFFECT OF NACL ON AKINETE DIFFERENTIATION IN THE CYANOBACTERIUM NOSTOC PUNCTIFORME." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1584.
Full textAbstract:
Nostoc punctiforme is a nitrogen-fixing, symbiotic/free-living cyanobacterium. There has been a great deal of research conducted on the genomic nature of N. punctiforme as it pertains to its ecologically important role in the nitrogen cycle in varied environments around the world. My study concentrated on the dormant cell type known as the akinete. Increasing concentrations of NaCl were used to follow the growth phases from germination to akinete formation (lag phase-logarithmic growth phase-stationary phase). I found that increased salt concentrations caused N. punctiforme to form akinetes faster when compared to the control. Germination rates were not greatly increased or shortened by salt concentrations at or below 40 mM NaCl. Damage to cells due to NaCl was observed between 105 mM and 500 mM. Physiological studies, such as this one, enable better quantifiable field research since the organism’s limitations under laboratory conditions are known. This research allows researcher to more accurately plan and pick study sites, develop field studies and gives a solid basis for comparison to the natural environment.
12
Thorsteinsson, Marc V. "Partial structural characterization of the cytoplasmic hemoglobin of Nostoc commune UTEX 584 expressed in Escherichia coli /." This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06232009-063505/.
Full text
13
Becker, Julia E. "Biosynthesis of Cyclic Peptides and Depsipeptides in NOSTOC SP ATCC 53789." Thesis, University of Hawaii at Manoa, 2002. http://hdl.handle.net/10125/6940.
Full textAbstract:
The cyanobacterium Nostoc sp. ATCC53789 produces two interesting families of natural products: the cryptophycins and the nostocyclopeptides. The structures of the cryptophycins, a class of tumor-selective cytotoxins, suggest the involvement of both peptide synthetases and polyketide synthases in their biosynthesis. The nostocyclopeptides are cyclic heptapeptides that feature the unnatural amino acid (2S, 4S)-4-methylproline and an unusual imine linkage between two of the amino acid residues. To identify the biosynthetic gene clusters for these peptides, a cosmid library was generated. Peptide synthetase adenylation domains from Nostoc sp. ATCC53789 were amplified by PCR, using degenerated primers based on core conserved sequences within these domains, and used to screen the library. The library was also screened with a probe derived from nosE, a gene involved in 4-methylproline biosynthesis in Nostoc sp. GSV 224. The nosE probe identified three overlapping cosmids, which when sequenced were found to contain genes consistent with nostocyclopeptide biosynthesis. The putative nostocyclopeptide gene cluster includes two peptide synthetase genes, the second of which terminates in a domain with homology to reductases. The cluster also contains genes that appear to be involved in the biosynthesis of 4-methylproline.xiii, 49 leaves
14
Onek, Leonzio Angole. "Calcium mediated regulation and calmodulin in the cyanobacterium Nostoc PCC 6720." Thesis, Lancaster University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316571.
Full text
15
Chapman, Karen Elizabeth. "Construction and characterisation of 'cyaC' mutants in the cyanobacterium 'Nostoc punctiforme'." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424019.
Full text
16
Mehner, Christian Michael. "Bioactive peptides from the cyanobacterial strains Tychonema sp. and Nostoc insulare." München Verl. Dr. Hut, 2008. http://d-nb.info/992163552/04.
Full text
17
Gonzalez, Alfonso Jr. "A trio of sigma factors control hormogonium development in Nostoc punctiforme." Scholarly Commons, 2019. https://scholarlycommons.pacific.edu/uop_etds/3621.
Full textAbstract:
Cyanobacteria are prokaryotes capable of oxygenic photosynthesis, and for many species, nitrogen fixation, giving cyanobacteria an important role in global carbon and nitrogen cycles. Furthermore, multicellular filamentous cyanobacteria are developmentally complex, capable of differentiation into different cell types, including cells capable of nitrogen fixation and cells for motility, making them an ideal platform for studying development, as well as for practical use in biotechnology. Understanding how developmental programmes are activated require an understanding of the role of alternative sigma factors, which are required for transcriptional activation in bacteria. In order to investigate the gene regulatory network and to determine the role of alternative sigma factors in hormogonium development, real time PCR and Next Generation RNA-seq were used to measure expression levels of genes involved in hormogonium development and to further characterise the nature of the hormogonium developmental programme in the filamentous cyanobacterium Nostoc punctiforme. The results support a model where a hierarchal sigma factor cascade activates hormogonium development, in which expression of sigJ activates expression of the sigma factors sigC and sigF, as well as a wide range of other genes, including those involved in the type IV pilus (T4P), chemotaxis-like systems, and cell architecture. SigC and SigF have more limited roles: cell division genes are dependent on SigC and pilA expression was stringently SigF-dependent. Interestingly, SigC was also found to enhance expression of sigJ during hormogonium development, implying a potential positive feedback loop between sigJ and sigC.
18
Thorsteinsson, Marc Victor. "Partial structural characterization of the cytoplasmic hemoglobin of Nostoc commune UTEX 584 expressed in Escherichia coli." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/43454.
Full text
19
Paulsrud, Per. "The Nostoc Symbiont of Lichens : Diversity, Specificity and Cellular Modifications." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5136-5/.
Full text
20
Beesley, Clare Elizabeth. "The analysis of heterocyst-specific sequences from the cyanobacterium nostoc PCC 6720." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239072.
Full text
21
Temple, Stephen James. "The isolation of heterocyst specific sequences from the cyanobacterium Nostoc PCC 6720." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305698.
Full text
22
Agervald, Åsa. "Maturation and Regulation of Cyanobacterial Hydrogenases." Doctoral thesis, Uppsala universitet, Mikrobiell Kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-110871.
Full textAbstract:
Accelerated global warming plus an increasing need for energy is an equation not easily solved, thus new forms of sustainable energy production are urgently requested. In this context hydrogen production based on a cyanobacterial system offers an environmentally friendly alternative for energy capture and conversion. Cyanobacteria can produce hydrogen gas from sun light and water through the combination of photosystems and hydrogenases, and are suitable to cultivate in large scale. In the present thesis the maturation process of [NiFe]-hydrogenases is investigated with special focus on transcription of the accessory genes encoding proteins needed for assembly of the large and possibly also for the small hydrogenase subunit. The cyanobacteria used are two N2-fixing, filamentous, heterocystous strains; Nostoc sp. strain PCC 7120 and Nostoc punctiforme PCC 73102. For a biotechnological exploration of hydrogen production tools for regulatory purposes are important. The transcription factor CalA (cyanobacterial AbrB like) (Alr0946 in the genome) in Nostoc sp. strain PCC 7120 was found to be involved in hydrogen metabolism by regulating the transcription of the maturation protein HypC. Further the bidirectional hydrogenase activity was down-regulated in the presence of elevated levels of CalA, a result important to take into account when optimizing cyanobacteria for hydrogen production. CalA regulates at least 25 proteins in Nostoc sp. strain PCC 7120 and one of the down-regulated proteins was superoxide dismutase, FeSOD. The characterization of FeSOD shows that it has a specific and important function in the oxidative stress tolerance of Nostoc sp. stain PCC 7120. Since CalA is involved in regulation of both the hydrogen metabolism as well as stress responses these findings indicate that Alr0946 is an important transcription factor in Nostoc sp. strain PCC 7120 active on a global level in the cell. This thesis adds more knowledge concerning maturation and regulation of cyanobacterial hydrogenases which might be useful for future large scale hydrogen.
23
Chávez, Hidalgo Lourdes Pilar. "Composición química y actividad antioxidante in vitro del extracto acuoso de Nostoc sphaericum (Cushuro), laguna Cushurococha-Junín." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2014. https://hdl.handle.net/20.500.12672/3897.
Full textAbstract:
Objetivo: Determinar la composición química y actividad antioxidante in vitro del extracto acuoso liofilizado de Nostoc sphaericum (Cushuro) de la laguna Cushurococha, Junín. Materiales y métodos: Estudio de enfoque cuantitativo; con diseño, descriptivo, observacional, transversal, la muestra biológica fue el extracto acuoso liofilizado de Nostoc sphaericum (Cushuro) que se recolectó de la laguna Cushurococha en el departamento de Junín. Se utilizaron los métodos Lowry, Antrona, Folin-Ciocalteu, el ensayo de captación de ABTS.+. Resultados: La cantidad, por muestra liofilizada, de proteínas solubles fue de 15.1mg/g, carbohidratos totales 949ug/g, polifenoles totales 2.98mg EAG/g; así también, el porcentaje de inhibición del radical ABTS.+ a una concentración de 0.15mg/mL de muestra liofilizada fue de 52%, un valor de IC50 entre 10-15 ug/mL y una capacidad antioxidante equivalente a trolox (TEAC-ABTS) igual a 0.384 ugEq. Trolox/ mg extracto de muestra seca. Conclusiones: El extracto acuoso liofilizado de Nostoc sphaericum constituye una buena fuente natural de antioxidantes.Tesis
24
Hill, Donna René. "Morphological, biochemical and molecular characterization of desiccation-tolerance in cyanobacterium Nostoc commune var. Vauch." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40154.
Full textAbstract:
Filaments of the desiccation-tolerant cyanobacterium Nostoc commune are embedded within, and distributed throughout, a dense glycan sheath. Analysis of the glycan of field materials and of pure cultures of N. commune DRH1 through light and electron microscopy, immunogold-labelling and staining with dyes, revealed changes in the pattern of differentiation in glycan micro-structure, as well as localized shifts in pH, upon rehydration of desiccated field material. A Ca/Si rich external (pellicular) layer of the glycan acts as a physical barrier on the surface of N. commune colonies. A purified fraction (> 12 kDa) of an aqueous extract of the glycan from desiccated field material contained glucose, N -acetylglucosamine, glucosamine, mannose and galactosamine with ratios of 3.1 : 1.4 : 1 : 0.1 : 0.06, respectively. Ethanol extracts of N. commune contained trehalose and sucrose and the levels of both became undetectable following cell rehydration. Elemental analysis of glycan extracts showed a flux in the concentrations of salts in the glycan matrix following rehydration of desiccated colonies. Intracellular cyanobacterial trehalase was identified using immunoblotting and its synthesis was detected upon rehydration of desiccated field cultures. Water-stress proteins (Wsp; molecular masses of 33, 37, and 39 kDa are the most abundant proteins in glycan), a water soluble UV-AlB-absorbing pigment, the lipid-soluble UV-protective pigment scytonernim, as well as two unidentified cyanobacterial glycoproteins (75 kDa and 110 kDa), were found within the glycan matrix. No evidence was found for either glycosylation, phosphorylation or acylation of Wsp polypeptides. NH2-terminal sequence analysis of the three proteins of Wsp were identical: Ala-Leu-Tyr-Gly-Tyr-Thr-Ile-Gly-Glu-Gln-X-Ile-Gln- Asn-Pro-Ser-Asn-Pro-Ser-Asn-Gly-Lys-Gln. An unidentified 68-kDa protein, the second most abundant protein in aqueous extracts of the glycan, was isolated and its N-terminal sequenced was determined: Ala-Phe-lle-Phe-Gly-Thr-Ile-Ser-Pro-Asn-Asn-Leu-Ser-Gly- Thr-Ser-Gly-Asn-Ser-Gly-Ile-Val-Gly-Ser-Ala. Gene bank searches with these sequences, and an internal sequence ofWsp (Glu-Ala-Arg-Val-Thr-Gly-Pro-Thr-Thr-Pro-Ile-Asp), identified homologies with various carbohydrate-modifying enzymes. Purified Wsp polypeptides associate with 1,4-β-D-xylanxylanohydrolase activity that was inhibited specifically by Wsp antiserum. In the absence of salt, Wsp polypeptides, and the water-soluble UV -A/B-absorbing pigments, form multimeric complexes through strong ionic interactions. The role of the glycan, and the protein and pigments that reside within it, in the desiccation tolerance of N. commune is discussed with respect to structure/function relationships.Ph. D.
25
Jaki, Birgit. "Biological screening of cyanobacteria and phytochemical investigation of Nostoc commune and Tolypothrix byssoidea /." Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13582.
Full text
26
Soler, Campmajó David. "Estudis cinètics i estructurals de la trans inteïna Npu DnaE de "Nostoc punctiforme"." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/285784.
Full textAbstract:
Les inteïnes són dominis proteics que mitjançant un procés de tall i unió s’autoescindeixen de la cadena polipeptídica precursora i catalitzen la unió de les seqüències flanquejants (exteïnes) mitjançant un enllaç peptídic. Actualment, la trans inteïna Npu DnaE és una de les que més s’utilitza en diferents aplicacions biotecnològiques. En aquest treball s’ha estudiat i comparat la termoestabilitat que presenta la inteïna Npu DnaE formant una única cadena polipeptídica, quan es troba partida en dos fragments associats i del fragment IN aïllat. Per altra banda, s’ha estudiat com afecta a l’activitat de la inteïna les substitucions de Cys1 i Cys+1 per una Ser. Finalment, s’ha estudiat i complementat el coneixement del procés associatiu dels fragments IN i IC a partir de tres variants de Npu DnaE amb diferents llargades del fragment IC, utilitzant ressonància magnètica nuclear.Inteins are protein domains that self-excise from a polypeptide chain precursor and catalyze the ligation of the flanking sequences (exteins) with a peptide bond. Currently, Npu DnaE is one of the best split inteins that is used in different biotechnological applications. In this work we have studied the thermal stability of this intein when it is forming a single polypeptide chain, when it is split into two fragments associated and when the IN fragment is isolated. Furthermore, we studied how the activity of the intein is altered when substituting Cys+1 and Cys1 by Ser. Finally, we have studied and complemented what is known about the associative process between IN and IC fragments. To accomplish this, we have studied by nuclear magnetic ressonance, three variants of Npu DnaE with different lengths of IC fragment.
27
Zhang, Ruojing. "The Investigation of Biophysical and Biological Function of PRPS from Nostoc PCC 7120." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1617630241200474.
Full text
28
Nascimento, Antônio Galvão do. "Métodos de purificação e efeitos da qualidade espectral da luz em Nostoc spp." Universidade Federal de Viçosa, 1998. http://www.locus.ufv.br/handle/123456789/10625.
Full textAbstract:
Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-06-09T17:59:24Z
No. of bitstreams: 1
resumo.pdf: 15291 bytes, checksum: ac7143b5fd5af7ee0507b1862b2f419a (MD5)Made available in DSpace on 2017-06-09T17:59:24Z (GMT). No. of bitstreams: 1 resumo.pdf: 15291 bytes, checksum: ac7143b5fd5af7ee0507b1862b2f419a (MD5) Previous issue date: 1998-09-10
Conselho Nacional de Desenvolvimento Científico e Tecnológico
A partir de um conjunto de 39 cianobactérias, foram purificados 14 isolados através de quatro métodos. Organismos que apresentam motilidade foram purificados por repicagens sucessivas ou por fragmentação de filamentos compostos por células vegetativas acoplado a repicagens sucessivas. Organismos sem motilidade puderam ser purificados por fragmentação de agregados de acinetos acoplada à esterilização com hipoclorito de sódio (comercial) ou por fragmentação de agregados de filamentos vegetativos envolvidos por bainhas rígidas acoplada à esterilização com hipoclorito comercial. Foram escolhidos os isolados Nostoc sp1(F16), Nostoc sp2(F40) e Nostoc piscinale (F108) para realizar determinações de concentração de ficobiliproteínas, caracteres morfológicos e o crescimento, sob luz verde e luz vermelha. Foi observada a ocorrência de adaptação cromática complementar somente em F16. F108 apresentou concentrações muito maiores de ficocianina (Pc) relativa a ficoeritrina (Pe) e F40 apresentou aproximadamente 50 % de ficocianina e 50 % de ficoeritrina em ambos os tipos de luz. A incubação em meio líquido, sob condições de agitação promoveu a formação de grumos de filamentos em F16 e F108, mas não em F40. Houve uma maior diferenciação de hormogônios em F16 e F108 sob luz vermelha, comparada à ocorrida sob luz verde e, devido a isso, ocorreu uma desagregação progressiva dos grumos nestes isolados sob luz vermelha, o que não foi observado sob luz verde. Em F40, não foram observados hormogônios em nenhum dos dois tipos de luz. Durante o crescimento de F16 e F108, foram observadas fases de interrupção de crescimento intermediárias a fases distintas de crescimento e F40 apresentou apenas uma única fase de crescimento. Propõe-se como hipótese que a diferenciação de hormogônios em F16 e F108 ocorra em fases específicas da curva de crescimento e que o fator determinante para a ocorrência de diferenciação destes filamentos seja a filtração seletiva da luz pelas camadas externas de células do grumo. Foi observada uma interação entre os efeitos da composição de ficobiliproteínas e da arquitetura das colônias sobre o incremento em biomassa. Em F16 e F108, a maior desagregação dos grumos sob luz vermelha, possivelmente seja a explicação do maior incremento de biomassa neste tipo de luz. Em F108, este maior incremento sob luz vermelha pode ser devido à maior concentração de Pc relativa a Pe. Em F40, o maior incremento de biomassa sob luz verde pode ser explicada pelas concentrações semelhantes de Pe e Pc em ambos os tipos de luz.
Among 39 isolates, 14 cyanobacteria were purified by four methods. Organisms with gliding motility were purified by sucessive transfers or by fragmentation of filaments composed of vegetative cells combined with sucessive transfers. Organisms without motility were purified by fragmentation of the akinete aggregates combined with sterilization with sodium hipoclorite or by fragmentation of aggregates of vegetative filaments surrounded by firm sheaths combined with esterilization with comercial hipoclorithe. The isolates Nostoc sp1(F16), Nostoc sp2 (F40) and Nostoc piscinale (F108) were chosen to make the determinations of phycobiliprotein concentration , morphological characters and growth, under green and red light. Complementary chromatic adaptation was observed only in F16. F108 showed much higher concentrations of phycocyanin relative to phycoerytrin, and F40 showed aproximately 50 % of phycocyanin and 50 % of phycoerytrin under the two kinds of light. Incubation in liquid medium, with agitation, promoted the formation of aggregates of filaments in F16 and F108, but not in F40 . A higher hormogonium differentiation was observed in F16 and F108 under red light than under green light and, consequently, a progressive desaggregation of the aggregates occurred in these isolates under red light, which xiiwas not observed under green light. Hormogonia were not observed in F40 under either light. The growth of F16 and F108 showed a interruption of the growth between two distinct growth periods and F40 showed only one growth period. It is proposed as a hypothesis that the hormogonium differentiation in F16 and F108 occurs at specific phases of the growth and that the determining factor of this differentiation is the selective filtration of light by the outer layers of cells of the aggregate. An interaction between the effects of the phycobiliprotein composition and the colony architecture on biomass increment was observed. In F16 and F108, the higher desaggregation of the aggregates under red light possibly is the reason for the higher biomass increment under this light regime. In F108, another reason for the higher biomass increment under red light may be the higher concentration of Pc relative to Pe. In F40, the higher biomass increment under green light may be explained by similar concentrations of Pe and Pc at the two light regimes.
29
Falch, Beatrix S. "Phytochemical and biological investigations of cyanobacteria, in particular of Fischerella ambigua and Nostoc sphaericum /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10882.
Full text
30
Kimani, Duane. "Biodiesel and Hydrogen Production : A Study of Nostoc sp. in Pulp and Paper Wastewater." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-125085.
Full textAbstract:
The modernized world is over-consuming low-cost energy sources that strongly contributes to environmental stress. As a consequence, the interest for environmentally friendly alternatives has increased immensely. One such alternative is utilizing the diazotrophic nature of the heterocystous filamentous cyanobacteria Nostoc sp. as feedstock for biodiesel and hydrogen production using pulp and paper wastewater – a phosphorous and nitrogen deficient medium. In this work, biodiesel and hydrogen production was studied with respect to three main aspects: biodiesel quality properties, lipid content and hydrogen production coupled with a preliminary study investigating the luminous effects on the biomass and biodiesel quality properties when exposed to low (50 μEm-2s-1), medium (150 μEm-2s-1) and high light (300 μEm-2s- 1). The preliminary study showed that an increase of light intensity was associated with parabolic results for biomass following the 10-day cultivation period, with the medium light intensity showing an average dried weight of at the most 203% greater than the two other light intensities. When analysing the FAME- composition, similar results were demonstrated for the fatty acid constituents preferred for biofuel applications, C18:1 and C18:2 fatty acids, where the low, medium and high light showed an accumulative 34.65, 43.1 and 31.6 dwt % respectively. The strain could be of interest as feedstock for biodiesel when cultivated in pulp and paper wastewater, due to the positive results pertaining to the lipid content and biodiesel quality properties. Following the 10-day cultivation period the lipid content obtained was 35.9 dwt %. The biodiesel quality properties were tested to assess the strains suitability for biodiesel and were tested to ensure its accordance to the standards on commercial biodiesel quality; European Standard for Biodiesel as heating oil (EN 14213) and European Biodiesel Standard (EN 14214). The critical parameters tested were the regulated (iodine value, cetane number, density, viscosity, pour point, cold filter plugging point, oxidative stability) and unregulated (FAME-composition) fuel properties. Results obtained showed values within the regulated values set by the different standards. However, due to a high saturated fatty acid content, the strain showed inadequate low temperature flow properties (cloud point, pour point and the cold filter plugging point). This study shows that this strain has a low potential for hydrogen production, with a hydrogen production of 0.13 nmol/mg dry wt/h following the 10-day cultivation period. This low hydrogen production could be attributed to the among other things the current growth phase of the cyanobacteria. Chemical analyses were conducted for revealing the total nitrogen, total phosphorus and chemical oxygen demand (COD) content. Following the 10-day cultivation period, the samples showed a 22% decrease in phosphorous concentration, 11% decrease in COD concentration and 51% increase of nitrogen concentration. The probable causes for this increase is the Nostoc’s diazotrophic nature and the ammonium excretion nitrogen fixation entails, as well as the nitrogen release following the final algal growth phase – the death phase. In conclusion, the results showed great potential, however, further studies are recommended investigating the changes that occurs during cultivation period to further assess the strains potential as well as assessing the continuity of the results with a greater initial cellular concentration. Nonetheless, due to the positive results obtained regarding the nutrient uptake, biodiesel and hydrogen production, this study shows potential for further optimization for the use of Nostoc grown in pulp and paper wastewater for wastewater treatment, biodiesel and/or hydrogen production.
31
Llavero, Pasquina Marcel. "Engineered light controlled cell development for enhanced hydrogen production in Nostoc punctiforme ATCC 29133." Thesis, Uppsala universitet, Mikrobiell kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-294854.
Full textAbstract:
The aim of this thesis is to enhance heterocyst-based hydrogen production inNostoc punctiforme ATCC 29133. We envision to do so by finely regulatingthe ratio of heterocyst in order to optimize the filament energy balance. Wehereby report the development of an optogenetic synthetic switch basedon the native PcpeC promoter. The optogenetic switch featured a 24-folddynamic range when measuring reporter sfGFP fluorescence. Such a geneticgate was conceived to artificially drive the expression of hetR, the masterregulator of heterocyst development. We achieved to induce enhancedheterocyst differentiation in the presence of ammonia only by changing thechromatic properties of the light source. Thus, the natural cell developmentregulation was substituted by effectively introducing a full person-drivencontrol over the process.
32
Ran, Liang. "Proteomic profiles and gene expressions in the symbiotically competent cyanobacterium Nostoc sp. PCC 73102 /." Stockholm : Department of Botany, Stockholm university, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6827.
Full text
33
Liu, Xuejun, and 劉學軍. "An eco-physiological study of the edible terrestrial cyanobacterium Nostoc flagelliforme: towards successfulartificial cultivation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29514836.
Full text
34
Sines, Brian James. "Isolation and partial characterization of a water stress protein of the desiccation-tolerant cyanobacterium Nostoc commune UTEX 584 expressed in Escherichia coli." Thesis, Virginia Tech, 1996. http://hdl.handle.net/10919/46434.
Full textAbstract:
A desiccation-tolerant cyanobacterium Nostoc commune accumulates a novel group of water stress proteins (Wsp) in response to cycles of repeated drying and rehydration. Antibodies, specific for Wsp, were used to screen a lambdafix II library of N. commune UTEX 584 Bam H1 DNA fragments and an 8.5-kb fragment, containing a gene cluster that synthesized a 59-kDa cross-reactive protein. The cloned fragment comprised five ORF’s. The ORF’s 59, 24, 22, 36, and 70, each potentially encode products of molecular weights of 59, 24, 22, 36, and 70-kDa, respectively. The 59 and 24 ORF products were found to be expressed in E. coli. The 59-kDa product of this fragment gives the strongest cross-reaction with the Wsp antiserum. The 59-kDa protein was partially purified. The 24-kDa product was successfully purified to homogeneity and partially characterized.
This study used E. coli strain DH10B transformed with the pTrc 99A plasmid. The pTre 99A contains the 8.5-kb gene cluster fragment of interest. The products of ORF 24 and 59 were isolated using an initial 40-60 % ammonium sulfate precipitation of a clarified E. coli cell lysate. The clarified cell lysate was then subjected to streptomycin sulfate precipitation. The cell lysate was then dialyzed extensively. The cell lysate was then applied to a Mono Q HR 5/5 anion exchange column using a 2 M KCl gradient elution procedure. The Mono Q column yielded a fraction containing both ORF products which eluted with approximately 400 mM KCl. This fraction was then applied to a Superose 12 HR 10/30 gel filtration column. The eluent fraction containing the ORF 24 product was then reapplied to the Superose 12 to yield the final fraction containing only the ORF 24 product. The final fraction of ORF 24 was purified to homogeneity as determined by SDS-PAGE analysis. Approximately 750 μg of ORF 24 was isolated. This preparation was used for characterization studies.
Characterization studies of ORF 24 consisted of an amino-terminal sequence analysis, an estimation of the molecular weight using gel filtration chromatography and SDS-PAGE analysis, and an analysis of enzymatic activity as suggested by amino acid sequence homologies. The amino-terminal sequence of ORF 24 is P V E Q R S H D. The molecular weight of ORF 24 using gel-filtration chromatography and SDS-PAGE analysis is 26-kDa and 23-kDa, respectively. From gene sequence analysis, the molecular weight of ORF 24 is known to be 24,340-Da. These data indicate that ORF 24 is a monomer. ORF 24 was found to have amino acid sequence homologies with a pectate lyase (E 4.2.2.2) periplasmic precursor from Erwinia caratovora subspecies and a dextransucrase (EC 2.4.1.5) precursor from Streptoccocus mutans GS-5. However, pectate lyase activity was not detected in cellular extracts over a 24 hour period. In addition, ORF 24 was not found to interact with 10 % substrate solutions of N-acetylglucosamine, pectin, UTEX 584 sheath material, DRH1 sheath material, sucrose, or glucose using thin layer chromatography. These studies indicate that the enzymatic activities proposed from amino acid sequence homologies have not been detected. The suggestion that ORF 24 is a water stress protein with a protective function on a structural level with regards to desiccation-tolerance requires further study.Master of Science
35
Holmqvist, Marie. "The Cyanobacterial Uptake Hydrogenase : Regulation, Maturation and Function." Doctoral thesis, Uppsala universitet, Mikrobiell Kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-129223.
Full textAbstract:
With accellerating global warming and pollution problems a change of energy regime is necessary. Solar energy offers a clean and unlimited energy source of enormous potential. Due to it’s intermittenet nature solar energy must be stored - ideally in the chemical bond of a carrier molecule. Hydrogen gas, H2, an energy carrier with water as only emission when used in a fuel cell, is considered to be the choise for the future. In this context cyanobacteria show promising potential as future H2 factories since they can produce H2 from solar energy and water. The main enzymes directly involved in cyanobacterial hydrogen metabolism are nitrogenases and hydrogenases. Cyanobacterial hydrogenases are either uptake hydrogenases or bidirectional hydrogenases and their maturation requires assistance of six maturation proteins and two hydrogenase specific proteases. In this thesis the transcriptional regulation, maturation and function of the cyanobacterial uptake hydrogenases were investigated in the filamentous, heterocyst forming strains Nostoc punctiforme ATCC 29133 and Nostoc sp. strain PCC 7120. Five genes, encoding proteins putatively involved in the maturation of the uptake hydrogenase were identified upstream the known maturation genes. Two transcription factors, CalA and CalB, were found interacting with the stretch of DNA forming the upstream regions of the uptake hydrogenase structural genes and the novel maturation genes. The expression of the uptake hydrogenase were heterocysts specific and the specificity mapped to a short promoter region starting -57 bp upstream the transcription start point. In addition, the function of the uptake hydrogenase was inserted in a metabolic context. Among the proteases, a conserved region was discovered possibly involved in determining the hydrogenase specificity. This thesis has given valuable information about the transcriptional regulation, maturation and function of the uptake hydrogenase in filamentous, heterocystous cyanobacteria and identified new targets for bioengineering of mutant strains with higher H2 production rates.
36
Sosa, Taco Celina Olenka. "Calidad nutricional y la aceptabilidad del producto obtenido por deshidratación osmótica del nostoc sphaericum (cushuro)." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2021. https://hdl.handle.net/20.500.12672/16456.
Full textAbstract:
Determina la calidad nutricional y la aceptabilidad
del producto obtenido por deshidratación osmótica del Nostoc sphaericum (cushuro).
El trabajo es de tipo tecnológico por el desarrollo de un nuevo producto.
La materia prima principal fue el Nostoc sphaericum (cushuro)
fue sometido a la inmersión de soluciones de sacarosa de 45°Brix, 50°Brix y 55°Brix
respectivamente, después de cada 24 horas se realizaron mediciones de peso y la
medición de grados brix de la solución por 10 días. Las pruebas de aceptabilidad fueron
realizadas por medio de un test de cinco puntos y evaluando atributos de color, olor y
sabor, fueron realizados a 95 estudiantes universitarios. Las soluciones de
45°Brix, 50°Brix y 55°Brix encuentran el equilibrio al octavo día de inmersión. El cushuro
deshidratado osmóticamente en base seca por cada 100g tiene 20.33g de proteínas, 5g
de grasas, 1581mg de calcio, 121mg de hierro. En cuanto al análisis de aceptabilidad
hubo diferencias significativas para cada atributo, siendo el más aceptado el de 50°Brix.
Concluye que los parámetros de deshidratación osmótica para el nostoc sphaericum
(cushuro) es 50°Brix en la solución osmótica, temperatura ambiente ,8 días de inmersión
y 8 horas de secado con aire caliente a 45°C.
37
Salem, Hassan Samy. "Phylogenetic Analysis of the Symbiotic Nostoc Cyanobacteria as Assessed by the Nitrogen Fixation (Nifd) Gene." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1282030524.
Full text
38
Alvarenga, Danillo Oliveira de. "Análise genômica e funcional da cianobactéria Nostoc sp. CENA67 e caracterização da sua comunidade microbiana associada." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-02022016-150801/.
Full textAbstract:
Nostoc é um gênero cianobacteriano com distribuição ubíqua que tem importância em diversos ecossistemas. Contudo, poucos genomas estão atualmente disponíveis para esse gênero. Enquanto Nostoc spp. são as cianobactérias mais comumente relatadas em relações simbióticas com fungos, animais, plantas e outros organismos, associações com outros micro organismos não receberam atenção similar. Como consequência das fortes interações entre cianobactérias e heterótrofos, culturas não axênicas são geralmente obtidas no isolamento dessas bactérias, o que proporciona uma oportunidade interessante para o desenvolvimento tanto de estudos genômicos quanto metagenômicos. Este trabalho teve como objetivo investigar as características genômicas e funcionais da linhagem Nostoc sp. CENA67, isolada de terra preta antropogênica, bem como estudar sua comunidade associada. Para esse fim, células de uma cultura não axênica de Nostoc sp. CENA67 foram sequenciadas com as plataformas MiSeq e Ion PGM e analisados com ferramentas genômicas e metagenômicas. A linhagem CENA67 de fato pertence à família Nostocaceae e possui algumas características em comum com cianobactérias do gênero Nostoc, porém diverge em certos aspectos morfológicos e filogenéticos do grupo típico de Nostoc, sugerindo que seja representante de um novo táxon. Além disso, seu genoma apresenta diferenças em relação aos genomas atualmente disponíveis para cianobactérias relacionadas ao gênero. A mineração desse genoma revelou 31 agrupamentos gênicos hipoteticamente relacionados à síntese de metabólitos secundários, a maioria dos quais não mostrou similaridade significativa com agrupamentos conhecidos. A análise de um agrupamento gênico de microviridina desvendou uma maior diversidade de genes para precursores dessa molécula do que se acreditava anteriormente, sugerindo que um número considerável de variantes ainda está a ser descoberta. A análise taxonômica da comunidade associada confirmou a dominância de cianobactérias na cultura, mas também revelou a presença de grande número de gêneros microbianos que normalmente são capazes de fixar nitrogênio atmosférico e estabelecer simbiose com plantas, incluindo Mesorhizobium, Sinorhizobium e Starkeya, entre outros. Rascunhos genômicos foram obtidos para Bradyrhizobium diazoefficiens, Bradyrhizobium japonicum, Burkholderia lata e Hyphomicrobium nitrativorans. Todavia, genes para fixação de nitrogênio não foram detectados nesses genomas, apesar de serem encontrados no genoma da cianobactéria e no metagenoma da comunidade, o que sugere que algumas populações podem estar sob pressão de seleção para a perda da capacidade de fixação de nitrogênio, provavelmente devido a este nutriente estar sendo fornecido pelo organismo mais abundante nesta comunidade, a cianobactéria. A análise funcional indicou vias exclusivas tanto à cianobactéria quanto à comunidade associada, e sugeriu a complementariedade de certos metabolismos. Os resultados possibilitam o aumento do conhecimento sobre a diversidade molecular e química do filo Cyanobacteria e levantam possíveis interações com micro organismos simbiontesNostoc is a cyanobacterial genus with ubiquitous distribution that is important in several ecosystems. However, few genomes are currently available for this genus. While Nostoc spp. are the most commonly reported cyanobacteria in symbiotic relationship with fungi, animals, plants, and other organisms, associations with other microorganisms have not received similar attention. As a consequence of tight interactions between cyanobacteria and heterotrophs, non-axenic cultures are usually achieved in the isolation of these bacteria, which provides an interesting opportunity for carrying out both genomic as metagenomic studies. This work aimed to investigate the genomic and functional characteristics of the strain Nostoc sp. CENA67, isolated from anthropogenic dark earth, and to study its associated community. For this purpose, cells from a non-axenic culture of Nostoc sp. CENA67 were sequenced with the platforms MiSeq and Ion PGM and analyzed with genomic and metagenomic tools. The strain CENA67 indeed belongs to the family Nostocaceae and presents some characteristics in common with cyanobacteria of the genus Nostoc, but diverges in certain morphological and phylogenetic aspects of the typical Nostoc group, suggesting that it is a representative of a new taxon. In addition, its genome presents differences in relation to the genomes currently available for cyanobacteria related to this genus. Genome mining revealed 31 gene clusters hypothetically related to the synthesis of secondary metabolites, most of which did not show significant similarity to known clusters. The analysis of a microviridin gene cluster unveiled a larger diversity of precursor genes for this molecule than was previously believed, suggesting that a considerable number of variants is still to be found. The taxonomic analysis of the associated community confirmed the dominance of cyanobacteria in the culture, but also revealed the presence of a great number of microbial genera that are usually capable of fixing atmospheric nitrogen and establishing symbiosis with plants, including Mesorhizobium, Sinorhizobium, and Starkeya, among others. Genomic drafts were obtained for Bradyrhizobium diazoefficiens, Bradyrhizobium japonicum, Burkholderia lata, and Hyphomicrobium nitrativorans. Nevertheless, genes for nitrogen fixation were not detected in these genomes, despite being found in the cyanobacterial genome and the community metagenome, suggesting that some populations might be under selection pressure for the loss of the ability to fix nitrogen, probably due to this nutrient being provided for the most abundant organism in this culture, the cyanobacterium. Functional analysis indicated pathways exclusive both to the cyanobacterium as to the associated community, and suggested the complementarity of certain metabolisms. The results allow the increase of the knowledge about the molecular and chemical diversity of the phylum Cyanobacteria and raise possible interactions with symbiotic microorganisms
39
Riley, Kelsey Wynne. "Evidence that a partner-switching regulatory system modulates hormogonium motility in the filamentous cyanobacterium Nostoc punctiforme." Scholarly Commons, 2018. https://scholarlycommons.pacific.edu/uop_etds/3135.
Full textAbstract:
Partner-switching regulatory systems (PSRSs) are utilized by many different bacteria to regulate a wide array of cellular responses, from stress response to expression of virulence factors. The filamentous cyanobacterium Nostoc punctiforme can transiently differentiate motile filaments, called hormogonia, in response to various changes in the environment. Hormogonia utilize a Type IV pilus (T4P) complex in conjunction with a secreted polysaccharide for gliding motility along solid surfaces. This study identified three genes, designated hmpU, hmpW, and hmpV, encoding the protein components of a PSRS involved in regulation of hormogonium motility in N. punctiforme. Although mutant strains with in-frame deletions in hmpU, hmpW, and hmpV differentiated morphologically distinct hormogonium-like filaments, further phenotypic analysis demonstrated significant distinctions among the strains. The ∆hmpW strain contained a higher percentage of motile filaments that moved faster than the wild-type strain, while the ∆hmpU and ∆hmpV strains consisted of fewer motile filaments that moved at a slower rate compared to wild type. Immunoblotting and immunofluorescence of PilA, the major component of the pilus in the T4P system, showed that although all mutant strains appeared to express similar levels of PilA protein, the ∆hmpU and ∆hmpV strains displayed reduced extracellular PilA. Lectin blotting and staining with fluorescently-labeled UEA lectin demonstrated a decrease in extracellular hormogonium polysaccharide in the ∆hmpU and ∆hmpV strains, consistent with the current understanding that the polysaccharide is secreted via the T4P system. Epistasis analysis demonstrated that the ∆hmpW, ∆hmpV double-deletion mutant strain displayed reduced spreading in plate motility assays, similar to the ∆hmpV single mutant. Together, these results support a model in which the HmpU phosphatase and HmpW serine kinase control the phosphorylation state of the HmpV protein, modulating its activity on a downstream target to ultimately promote activation of the T4P motor complex and enhance hormogonium motility.
40
Vaz, Marcelo Gomes Marçal Vieira. "Diferenciação celular em Nostoc spp: efeito da intensidade luminosa e do padrão de sobreposição dos filamentos." Universidade Federal de Viçosa, 2010. http://locus.ufv.br/handle/123456789/5321.
Full textAbstract:
Made available in DSpace on 2015-03-26T13:51:49Z (GMT). No. of bitstreams: 1
texto completo.pdf: 1357885 bytes, checksum: 94cbad5284c486e24d0ad442975d1eda (MD5)
Previous issue date: 2010-06-25Conselho Nacional de Desenvolvimento Científico e Tecnológico
In Nostoc isolates, the vegetative cells multiplication and differentiation of some of them in heterocyst is the life cycle phase in which biomass production occurs. In other phase, many environmental changes can trigger hormogonium differentiation, a transient and a non-growth state. The use of cyanobacteria strains in biotechnological processes have been studied for many years, however, the production of biomass is influenced, and can be limited, by the fact that the colonies growth intensify the selfshading. Consequently, changes in light intensity and quality received by cells can occur. The aims of this work were: 1) to characterize biomass and pigments production by Nostoc isolates in response to changes in light intensity; 2) to analyze the effect of pre-cultivation and exposure in different light intensities in the same parameters and in cellular differentiation processes; 3) and to relate, for isolate Nostoc CCLFM XXI, growth phases to predominant cellular differentiation processes. The greater biomass production was achieved at 20, 45 and 75 μmoles m-2 s-1, respectively in Nostoc CCLFM I, VIII and XXI. In Nostoc CCLFM I, only phycoerithrin content changed with light intensity, been maximum at 15 μmoles m-2 s-1, decreasing with increasing light intensities. Pigment contents, in Nostoc CCLFM VIII did not vary with light intensities. In Nostoc CCLFM XXI phycocyanin and alophycocyanin contents varied with light intensity, reaching a maximum at 45 μmoles m-2 s-1, been constant up to 105 μmoles m-2 s-1. Biomass pre-cultivated at 15 μmoles m-2 s-1, when exposed to lower light intensities led to an intense akinetes differentiation in Nostoc CCLFM VIII and XXI, fact that did not occur in Nostoc CCLFM I. When biomass pre-cultivated at 75 μmoles m-2 s-1 were exposed to lower light intensities, filaments with smaller cells than vegetative ones were observed, indicating probably, the occurrence of hormogonium differentiation in Nostoc CCLFM I and VIII. When cultivated at 15 μmoles m-2 s-1, Isolate XXI showed intense akinetes differentiation, and when cultivated at 60 μmoles m-2 s-1 it showed distinct cellular differentiation patterns in phases in which biomass production was not observed. Hormogonia were observed only in the early non-growth phase, while akinetes were observed in middle and late non-growth phases. Therefore, there is relation between light intensity and patterns of cellular differentiation. In lowest light intensities the akinetes differentiation predominates over other differentiation process. However, in higher intensity hormogonia and akinetes were observed, with hormogonia associated with the first non-growth phase and akinetes with middle and late nongrowth phase, indicating a sequence in which cellular differentiation occur, probably related with light energy available to photosynthesis.
Em isolados do gênero Nostoc, a multiplicação das células vegetativas e a diferenciação de algumas células em heterócitos em intervalos regulares é a etapa do ciclo de vida em que ocorre a produção de biomassa. Em outra etapa do ciclo de vida, vários fatores do ambiente podem induzir a diferenciação de hormogônios, filamentos nos quais não ocorre produção de biomassa. A aplicação biotecnológica de cianobactérias pode ser limitada pela intensificação do auto-sombreamento durante o crescimento destas em foto-biorreatores. Em conseqüência, pode ocorrer diminuição na intensidade e alteração da qualidade espectral da luz que atinge as células. Os objetivos deste trabalho foram: 1) caracterizar a produção de biomassa e de pigmentos por isolados do gênero Nostoc cultivados em diferentes intensidades luminosas; 2) analisar o efeito do pré-cultivo e subseqüente exposição a diferentes intensidades luminosas sobre os mesmos parâmetros e sobre os processos de diferenciação celular e 3) caracterizar durante o cultivo de Nostoc CCLFM XXI em duas intensidades luminosas, a relação das fases de crescimento com os processos de diferenciação celular predominantes. As maiores produções de biomassa foram obtidas a 20, 45 e 75 μmoles m-2 s-1, respectivamente em Nostoc CCLFM I, VIII e XXI. Em Nostoc CCLFM I, apenas a concentração de ficoeritrina variou com a intensidade luminosa, apresentando-se máxima a 15 μmoles m-2 s-1, e diminuindo com aumentos na intensidade luminosa. As concentrações de pigmentos em Nostoc CCLFM VIII não variaram com a intensidade luminosa. As concentrações de ficocianina e aloficocianina, em Nostoc CCLFM XXI, variaram com a intensidade luminosa, atingindo um máximo à 45 μmoles m-2 s-1, e mantendo-se constantes nas maiores intensidades. O pré-cultivo a 15 μmoles m-2 s-1 e exposição às baixas intensidades luminosas levou, em Nostoc CCLFM VIII e XXI a uma intensa diferenciação de acinetos, o que não ocorreu para Nostoc CCLFM I. Quando o pré-cultivo foi realizado a 75 μmoles m-2 s-1, observou-se, em Nostoc CCLFM I e VIII, filamentos com células menores que as células vegetativas, indicativo de diferenciação de hormogônios. Nostoc CCLFM XXI quando cultivado a 15 μmoles m-2 s-1 apresentou intenso padrão de diferenciação de acinetos, ao passo que o cultivo a 60 μmoles m-2 s-1 apresentou distintos padrões de diferenciação celular nas faixas de parada de produção de biomassa. Nas fases iniciais de cultivo houve predominância de hormogônios, e de acinetos nas fases intermediária e final da curva. Desta forma, há uma relação entre intensidade luminosa e diferenciação celular, sendo que as mais baixas levam à diferenciação de acineto. No entanto, em maiores intensidades, observase tanto diferenciação de hormogônios quanto de acinetos, sendo os primeiros observados na primeira parada de produção de biomassa e os acinetos nas faixas mais tardias de parada, indicando uma sequência na ocorrência destes processos relacionada à disponibilidade de energia luminosa adequada à fotossíntese.
41
Oliveira, Cristiane Alves de. "Caracterização da produção de pigmentos e da atividade antioxidante de Nostoc spp. sob diferentes intensidades luminosas." Universidade Federal de Viçosa, 2012. http://locus.ufv.br/handle/123456789/5353.
Full textAbstract:
Made available in DSpace on 2015-03-26T13:51:56Z (GMT). No. of bitstreams: 1
texto completo.pdf: 1647302 bytes, checksum: 907782aa4c5aca00a3a2aaadedd6d8f0 (MD5)
Previous issue date: 2012-07-06Fundação de Amparo a Pesquisa do Estado de Minas Gerais
Cyanobacteria used for centuries as a food has antioxidant mechanisms highly developed and production capacity higher than any other agricultural system, presenting a great potential as a source of natural antioxidant compounds, and various other compounds. One of the factors that interfere with the metabolism of photosynthetic organisms is the level of incident light, yet for cyanobacteria are not well understood the relations between luminosity, bioactive compounds and antioxidant activity. Under this approach, the objective of this study was to determine the influence of different light intensities on antioxidant activity of cyanobacteria of the genus Nostoc spp., and on the levels of some of the main antioxidant compounds found in their cells: the pigments phycobiliproteins (phycocyanin, allophycocyanin and phycoerythrin), carotenoids and chlorophyll, and phenolic compounds. The antioxidant activity was determined by the percentage of inhibition of the radical 2,2-diphenyl-1-picryl hydrazyl (DPPH ) and phenols were determined using the Folin-Cicalteau. The data from this study demonstrated that significant variations can occur for the pigment and antioxidant activity between narrow bands of light intensity, thus, a precise definition of the intensity applied through response curves previously constructed is necessary in according to biotechnological interest in question. The lowest intensities were more advantageous in terms of yield pigments, antioxidant potential and phenolic compounds. The decreased level of chlorophyll and phycobiliproteins in higher irradiances were observed, probably being prevention against photo-oxidative damage caused by free radical generation. However, for carotenoids was observed in some instances increase the content of higher irradiances, which could reflect their function as heat sinks of the light energy absorbed in excess and as antioxidant agents of the photosynthetic apparatus. The phycobiliproteins was the major contributor to total antioxidant status at lower intensities, while for higher intensities are the carotenoids. However, not always the behaviors observed were similar between the biocompostos contents and antioxidant activity, since this relationship may prove to be quite complex, requiring a qualitative and quantitative determination of many compounds that may have antioxidant properties and use of highly purified extracts. In addition, the methodology used to determine the antioxidant activity could also be a source of variation, generating inconsistent results between the content of bioactive compounds and antioxidant activity.
As cianobactérias, utilizadas há séculos como alimento, possuem mecanismos antioxidantes altamente desenvolvidos e produtividade superior a qualquer outro sistema agrícola, apresentando, portanto grande potencial como fonte de compostos antioxidantes naturais, além de vários outros biocompostos. Um dos fatores que mais interferem no metabolismo dos organismos fotossintetizantes é o nível de luz incidente, todavia para cianobactérias não são bem comprendidas as relações entre luminosidade, compostos bioativos e atividade antioxidante. Sob este enfoque, o objetivo deste trabalho foi determinar a influência de diferentes intensidades luminosas sobre a atividade antioxidante de cianobactérias do gênero Nostoc spp., e sobre os níveis de alguns dos principais compostos antioxidantes presentes em suas células: os pigmentos ficobiliproteínas (ficocianina, aloficocianina e ficoeritrina), carotenóides e clorofila a, além de compostos fenólicos. A atividade antioxidante foi determinada pelo percentual de inibição do radical 2,2-difenil-1-picril hidrazil (DPPH ) e os fenóis foram determinados pelo método Folin-Cicalteau. Os dados deste trabalho mostraram que variações significativas podem ocorrer para os teores de pigmentos e atividade antioxidante entre faixas de intensidade luminosas estreitas; assim, uma definição precisa da intensidade aplicada, através de curvas de resposta previamente construídas é necessária de acordo com o interesse biotecnológico em questão. As menores intensidades se mostraram mais vantajosas em termos de rendimento de pigmentos, potencial antioxidante e conteúdo de compostos fenólicos. A diminuição do teor de clorofila a e ficobiliproteínas em maiores irradiâncias foram observadas, sendo provavelmente uma estratégia de prevenção contra o dano foto-oxidativo ocasionado pela geração de radicais livres. No entanto, para carotenóides, observou-se em alguns momentos aumento do conteúdo em maiores irradiâncias, o que poderia refletir suas funções como dissipadores da energia luminosa absorvida em excesso e como agentes antioxidantes do aparato fotossintético. As ficobiliproteínas foram as maiores contribuintes para totalidade da defesa antioxidante nas menores intensidades, enquanto que para as maiores intensidades foram os carotenóides. No entanto, nem sempre foram observados comportamentos semelhantes entre os teores de biocompostos e a atividade antioxidante, já que esta relação pode se mostrar bastante complexa, sendo necessária uma determinação quali e quantitativa dos inúmeros compostos que podem apresentar propriedades antioxidantes e utilização de extratos altamente purificados. Além disso, a própria metodologia utilizada para a determinação da atividade antioxidante também poderia ser uma fonte de variação, gerando resultados inconsistentes entre o teor de compostos bioativos e atividade antioxidante.
42
Angeloni, Stephen V. "Characterization of the nifUHD cluster and a new myoglobin-like gene from Nostoc commune UTEX 584." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/37418.
Full textAbstract:
Sequence analysis of the entire 3.5 kb HindIII genomic DNA fragment previously isolated from Nostoc commune UTEX 584 (Defrancesco and Potts 1988), determined the exact locations of the nifU, nifH, and nifD genes and identified two potential stem loop structures, a direct repeat, and an ORF that codes for a protein with a predicted amino acid sequence similar to that of myoglobin from Paramecium caudatum.
The N. commune UTEX 584 myoglobin-like protein has a predicted length of 118 amino acids and molecular mass of 12,906 Da. A PCR copy of the gene (glbN) was cloned for overexpression of the protein. The recombinant protein was purified and used for spectral analysis and for the production of polyclonal antisera.
Treatment of the recombinant protein with dithionite and CO resulted in spectral shifts characteristic of hemoproteins that bind oxygen. While some of the spectral characteristics are unique to the protein, in general the spectra were more like those of globins than cytochromes. Based on these characteristics and the sequence similarity to the P. caudatum mnyoglobin, we proposed the name cyanoglobin, with the gene designation glbN and the protein designation GlbN.
Western analysis of GlbN expression was performed on N. commune UTEX 584 and two species of Anabaena (Anabaena sp. PCC 7120 and Anabaena variabilis). In N. commune UTEX 584 a protein with a molecular mass similar to that predicted for GlbN was detected. This protein was produced in increased amounts under the same growth conditions that resulted in increased production of nitrogenase reductase (the nifH gene product). No proteins of similar size to GlbN were detected in Anabaena sp. PCC 7120 or A. variabilis.
A possible function of GlbN may be for oxygen storage, transport, or protection of the nitrogenase system. These functions as well as those of the direct repeat and the potential stem loop structures and their relationship to nitrogen fixation or other physiological processes in N. commune UTEX 584 require further analysis.Ph. D.
43
Thorsteinsson, Marc Victor III. "Structural and Functional Characterization of Cyanoglobin: A Peripheral Membrane Hemoglobin in Nostoc commune UTEX 584 (Cyanobacteria)." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/29827.
Full textAbstract:
Investigations of the nitrogen fixing (nif) genes in the cyanobacterium Nostoc commune UTEX 584 revealed a gene encoding a hemoprotein, named cyanoglobin. The cyanoglobin gene was isolated and subcloned into Escherichia coli previously. Cyanoglobin possesses a high oxygen affinity. The study presented here investigated the functional role of cyanoglobin, and encompassed the determination of the kinetic basis for the high oxygen affinity of cyanoglobin through kinetic studies utilizing stopped-flow spectrophotometry and flash photolysis. In addition, studies of cyanoglobin, in the presence of a variety of ligands, employed as structural probes of the distal pocket architecture, are presented. These data are interpreted in terms of structural models of cyanoglobin produced by homology modelling and hemoglobins with known crystal structures. Cyanoglobin coordinated oxygen and a variety of ligands with high rates of association, which explained the high oxygen affinity of cyanoglobin. Cyanoglobin possessed high rates of autoxidation and hemin loss. The ligand binding behavior of cyanoglobin was more similar to leghemoglobin than to sperm whale myoglobin. The ligand binding behavior of cyanoglobin is explained in terms of a highly reactive, and solvent exposed, heme-iron. The 5' region of glbN interacted with NtcA, the global regulator of nitrogen metabolism in cyanobacteria, which may provide an indication of the nitrogen deprivation signal required for cyanoglobin expression in vivo. Finally, the isolation and N-terminal sequencing of a potential cyanoglobin homolog in Anabaena sp. strain PCC 7120 is presented. Collectively, the data obtained in this study may support the model of cyanoglobin function described by Hill, et al., that cyanoglobin sequesters oxygen, and presents it to, or is a part of, a terminal cytochrome oxidase complex in Nostoc commune UTEX 584 under microaerobic conditions, when nitrogen fixation, and thus ATP demand, is maximal.Ph. D.
44
Joardar, Vinita. "Molecular analysis of genes involved in carbohydrate metabolism in the desiccation-tolerant cyanobacterium Nostoc commune UTEX 584." Diss., Virginia Tech, 1995. http://hdl.handle.net/10919/40311.
Full textAbstract:
Synthesis of water stress proteins (Wsp) is induced upon repeated desiccation and rehydration of immobilized cells of the desiccation-tolerant cyanobacterium Nostoc commune UTEX 584 (Nostoc 584). The Wsp polypeptides synthesized and secreted by field material of N. commune have been extensively characterized and shown to exist as three isoforms with molecular masses of 33, 37 and 39 kDa. In order to understand the role of Wsp in the mechanism of tolerance to water stress an attempt was made to isolate the gene(s) that encodes Wsp in Nostoc 584. A polyclonal antibody raised against a mixture of the isoforms was used to screen expression libraries (phage and plasmid) of Nostoc 584 genomic DNA fragments. This work presents the analysis of clones, isolated from the expression libraries, which cross react with Wsp antiserum. Sequencing of the DNA from one of the cross reacting clones revealed an incomplete open reading frame (ORFA) that showed strong similarity to two fructose bisphosphate aldolases, CfxA and CfxB, from the photosynthetic purple non-sulfur bacterium, Rhodobacter sphaeroides. A promoter region present upstream of ORFA is recognized by RNA polymerase from E. coli. Further upstream of the promoter lies trnK encoding lysyl-tRNA, identified by evident similarity to the corresponding gene from the chloroplast of the liverwort, Marchantia polymorpha. The remainder of the aldolase gene (fba) was isolated using the colony hybridization technique. Sequence analysis of DNA from the second cross reactive clone revealed six ORFs (ORFs 1 through 6).The products of ORFI and ORF2 are overproduced in this clone. The polypeptide encoded by ORFI shows very strong cross-reactivity with the polyclonal Wsp antibody, whereas ORF2 does not. Database searches using the deduced amino acid sequences of the six ORFs have provided clues to the possible identities of these ORFs. ORF6 shows correspondence with a protein, in Arabidopsis thaliana, which is induced in response to cold, abscissic acid and water stress. The common feature shared by ORFs 1 to 5 is that the highest similarities are observed with enzymes involved in carbohydrate metabolism. ORFs 1 through 5 may possibly represent a novel cluster of genes that form all or part of an operon involved in the metabolism of carbohydrates in Nostoc 584. Fructose bisphosphate aldolase (EC 4.1.2.13) is a key enzyme in carbohydrate metabolism, playing a role in glycolysis as well in the Calvin cycle of carbon dioxide fixation. The potential roles played by aldolase and the products of ORFs 1 through 5 in overall carbon metabolism of Nostoc commune UTEX 584 are discussed.Ph. D.
45
Wase, Nishikant V. "Proteomic and metabolomic analysis of the effects of UV-A radiation on the cyanobacterium nostoc punctiforme ATCC 29133." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557618.
Full textAbstract:
Over the last two decades, thinning of the ozone layer has raised serious concerns throughout the world, since it allows penetration of harmful ultraviolet radiation (UV-R) onto the Earth. Ultraviolet radiation (UV-R, 280-400 nm) has both direct and indirect effects on living organism. Both UV-A and UV-B have deleterious effect on living organisms. Numerous studies were undertaken in the past that have attempted to elucidate the biological effect of UV-B on photosynthetic organisms such as higher plants and microbes such as green algae and cyanobacteria, but there is only very limited knowledge about the effect of UV-A radiation on photosynthetic organisms. In the context of climate change and ozone depletion, it is clearly beneficial to understand the physiological and underlying molecular mechanism of UV-A response of cyanobacteria. This thesis primarily serves to generate understanding of response of cyanobacterium at the proteome and metabolome level in response to UV-A radiation. During this PhD project, a cyanobacterium was selected as an organism of choice because it has a geological past that can traced back to the Precambrian era, long before the production of the present ozone layer. Because of their geological past, cyanobacteria were thought to be well equipped in sustaining UV-R. In the present study, the filamentous cyanobacterium Nostoc punctiforme ATCC 29133 was used as a model organism to understand the effect of UV-A radiation on the physiology and the underlying molecular response. In order to assess the effects that environmental UV-A perturbation has on regulatory networks and pathways of N. punctiforme, a quantitative proteomics investigation was performed using soluble proteome sample. A total of 572 unique proteins were found in both studies constituting 8.41 % of the total proteome. Effect of short-term exposure (4h, 12h, 24h) and long-term exposure (20 days) was elucidated with the recent and powerful mass spectrometry based approach using iTRAQ (isobaric tag for relative and absolute quantification) methodology. Approximately, 32 and 61 proteins were found significantly changed in abundance during short-term and long-term exposure respectively. Abundance of some of the metabolically important proteins (13) were assessed using pSRM (pseudo selected reaction monitoring) and a strong correlation with the iTRAQ dataset was observed. Further, using HPLC, it was observed that UV-A has strong effect on photosynthetic accessory pigments (UV-A treatment period 4, 8, 12, 24 hours, 3, 5, and 7 days). An initial increase in carotenoids, ~-carotene, astaxanthin, and zeaxanthin was observed which later on decreased. An induction of scytonemin production during an acclimatization phase (4 hrs) was also observed. Using GC-MS, 62 compounds of known chemical structures were identified. Statistically significant elevated levels of glycine, alanine, tyrosine, proline, malate and succinic acid was observed (treatment interval periods 1, 3, 5, 7, 9, and 11 days), indicating a possible role of these metabolites during UV-A stress. Under prolonged exposure, UV-A not only substantially retarded the growth of N. punctiforme but a lowered abundance of photosynthetic apparatus and phycobilisomes was also observed. A number of targets (3 proteins) that are believed to have a strong role in the UV-sensing and signal transduction were also identified. Additionally, it was observed that long-term exposure causes the induction of increased protein scaffolding, redox rebalancing, and DNA repairing. In contrast, short-term exposure causes an immediate response from both the primary photosynthetic machineries, and also the secondary pigmentation apparatus. Additiona"y increased abundance of heat shock proteins was observed in both short-term and long-term treatment condition. Fina"y, a comparison of iTRAQ and pSRM data reaffirms the caveat regarding underestimation of quantitative measurements using iTRAQ. As a thesis closure, a comprehensive proteomics and metabolomics characterization of effect of UV-A stress in a model cyanobacterium N. puncfiforme ATCC 29133 is presented. The compilations of established analytical tools used to infer both qualitative and quantitative biological observations can also be adapted to other systems. Suggestions for future work are made.
46
Howell, Larry Daniel II. "Characterization of IphP from Nostoc commune UTEX 584 and a Dual Specificity Protein Phosphatase from Anabaena PCC 7120." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30344.
Full textAbstract:
Protein phosphorylation is utilized universally as a mechanism of signal transduction. However, the use of tyrosine phosphorylation by bacteria has been a matter of dispute. Conventional wisdom dictated that "prokaryotic phosphorylation" was typified by phosphorylation of histidine and aspartate residues of proteins, while "eukaryotic phosphorylation" was characterized by modification of serine, threonine, or tyrosine residues. Increasing numbers of reports have emerged challenging the traditional view of "prokaryotic" and "eukaryotic" phosphorlyation. One of the strongest links unifying prokaryotic and eukaryotic protein phosphorylation to date is IphP, a genomically-encoded dual-specificity protein phosphatase from the cyanobacterium Nostoc commune UTEX 584 bearing the active-site signature sequence of eukaryotic tyrosine-specific and dual-specificity protein phosphatases.
The catalytic properties and substrate specificity of IphP were examined in detail. The enzyme was able to discriminate among a variety of exogenous peptides and proteins. Kinetic studies revealed that IphP favors protein / peptide substrates over low molecular weight compounds.
Heparin effected IphP activity in a substrate-dependent manner. Enzyme activity toward casein (P-Ser) and MAP kinase (P-Thr/P-Tyr) was stimulated in the presence of the polyanion, whereas activity was inhibited by heparin toward other protein substrates. Both stimulation and inhibition by heparin were dose-dependent. The ability to stimulate IphP activity toward select substrates was attributed to the ability of heparin to recruit the enzyme and substrate to the same microenvironment.
To facilitate future genetic studies examining the role of tyrosine phosphorylation in cyanobacteria, we searched for evidence of protein tyrosine phosphorylation in Anabaena PCC 7120. In a collaborative effort with the laboratory of Dr. Potts, tyrosine phosphorylated proteins were identified in Anabaena utilizing several approaches, including comparative labelling with alpha- vs gamma-32P-ATP, phosphoamino acid analysis, and selective hydrolysis with a tyrosine specific protein phosphatase. Together, these data unequivocally demonstrate the presence of tyrosine-phosphorylated proteins in Anabaena PCC 7120.
Extracts of Anabaena PCC 7120 were examined for protein tyrosine phosphatase activity. An apparent PTP activity was detected, partially purified, and characterized. The protein phosphatase was ~38kDa by SDS-PAGE and sucrose density gradient centrifugation and displayed dual-specificity protein phosphatase (DSP) activity in vitro. The enzyme was localized to the periplasm and was thus assigned the title PAD, for Periplasmic Anabaena DSP. Periplasmic phosphoproteins of ~120 and 55 kDa that had been radiolabelled in vitro were dephosphorylated by partially purified PAD. PAD activity varied in vivo ~5-fold in a rhthymic, seemingly diurnal manner. Periplasmic proteins, including the 55kDa protein, were labelled in vivo and the degree of radiolabel incorporated into these proteins varied inversely with PAD activity.Ph. D.
47
Rivera, Carcamo Maria. "Optimization of Western Blot for detection of cellspecific localization of DNA binding protein fromstarved cells (Dps) in Nostoc punctiforme." Thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198683.
Full textAbstract:
Cyanobacteria belong to the oldest organisms of our planet. They use photosynthesis to produce ATP and gain biomass from carbon dioxide. The cyanobacteria Nostoc punctiforme is a filamentous bacterium that consists of two different types of cells, vegetative cells and heterocysts. The type of cell it differentiates into depends on the media they grow in. In an ammonium-rich medium, the N.punctiforme consists of vegetative cells that differentiate into heterocysts when in the medium is changed to a low-concentration ammonium medium. The ammonium-binding nitrogenase in the heterocysts does not work in an oxidative environment. During oxidative stress, N.punctiforme produces Dps (DNA binding protein from starved cells) which protects DNA. In the heterocysts the nitrogenase produces hydrogen as a side product. The hypothesis is that Dps is cell specific. In order to study this protein, a fusion of the promotor of Dps and GFP (Green Flourescent Protein) was constructed. To detect GFP, optimization of a Western Blot (WB) for GFP was performed. Protein samples were analyzed in strains of N.punctiforme. In strain 12A, the production of GFP was visualized but the band was not specific. Several attempts of optimization of the WB procedure were performed, but none of them showed clear specific protein detection in the N.punctiforme strains. Further optimization of the WB protocol is needed.
48
Faulhaber, Katharina [Verfasser], and Iris [Akademischer Betreuer] Maldener. "Detaillierte Charakterisierung von AmiC2, einem Schlüsselenzym für die intrafilamentöse Kommunikation in Nostoc punctiforme ATCC29133 / Katharina Faulhaber ; Betreuer: Iris Maldener." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/1199470228/34.
Full text
49
Huamaní, Zavaleta Wendy Nicole, and Carhuancho Jesus Isaias Marx Bejarano. "Efecto hepatoprotector del consumo de Nostoc commune (cushuro) frente al daño inducido por dietas ricas en sacarosa en ratones." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2022. https://hdl.handle.net/20.500.12672/17916.
Full textAbstract:
Evalua el efecto hepatoprotector del consumo de Nostoc commune (cushuro) frente al daño inducido por dietas ricas en sacarosa en ratones. Diseño de tipo experimental. Se emplearon 28 ratones macho con peso promedio de 30 ± 6,2 g y pulverizado de cushuro. Los animales fueron distribuidos en cuatro grupos recibiendo las siguientes dietas durante 50 días: Grupo I: dieta A (sacarosa 10%), grupo II: dieta B (sacarosa 36,5%), grupo III: dieta C (sacarosa 36,5% + cushuro 1%) y grupo IV: dieta D (sacarosa 36,5% + cushuro 3%). Posteriormente se extrajo el hígado y se realizó los análisis bioquímicos e histológicos. El estadístico ANOVA se aplicó para los datos simétricos y para los asimétricos, Kruskall-Wallis. En los grupos III y IV se observó que los niveles de triglicéridos (p<0.05) disminuyeron y también se observó una mejor conservación a nivel histológico. El consumo de Nostoc commune (cushuro) presenta efecto hepatoprotector expresado en la disminución de triglicéridos y la conservación a nivel histológico frente al daño inducido por dietas ricas en sacarosa en ratones.
50
Baltodano, Torres Celia Candy. "Evaluación de una crema dermocosmética con potencial actividad antioxidante y efecto humectante a base del extracto de Nostoc sphaericum “cushuro”." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/7750.
Full textAbstract:
Publicación a texto completo no autorizada por el autorElabora y evalúa la capacidad antioxidante y humectante de una crema dermocosmética a base del extracto liofilizado del Nostoc sphaericum “cushuro”. En primera instancia se realiza un tamizaje fitoquímico cualitativo para determinar los metabolitos que contiene la muestra en estudio, dando como positivo las pruebas de Dragendorf, Mayer, Bertrand, Sonenhei (alcaloides), saponinas y shinoda (flavonoides), a su vez da negativo para la prueba de tricloruro (fenoles); sin embargo, para determinar la actividad antioxidante de la crema, se realiza el método de DPPH, dándonos un IC50= 138.18mg/mL para la crema base, IC50= 25.37 mg/mL para la crema de concentración de 0.25%, IC50= 20.05 mg/mL para la crema de 0.5% y IC50= 19.95 mg/mL para la crema de 1%; con lo cual, estos valores nos indica que la crema de mayor concentración es la que tiene mayor actividad antioxidante. Se evalúa la estabilidad de la crema así como también el efecto humectante de la crema al 1%,sobre personas con piel seca utilizando el equipo DermAnalyzer, el cual indica el grado de humectación que la piel se encuentra, se utiliza tres cremas (crema base, crema comercial y crema del extracto liofilizado), de los cuales, la piel expuesta a la crema base mantiene su condición de piel seca, mientras que la crema en estudio, arroja valores positivos de humectación, similares al de la crema comercial.
Tesis