Podcasts about mastigocladus

The most asexual episode…that will blow you away with the most F-bombs! Oscillatoria, and all cyanobacteria, are slimy, scummy, invisible…they do not need to be handsome, they are their own partners, and they are EVERYWHERE! You cannot escape them, they will even tear themselves apart in order to hitch a ride on your muddy sneaker….follow you home..and terrorize you with their overt photosynthetic efficiency…and existence…and capabilities to survive for over 3.5 billion years without ever getting laid! However dreadful their lives may seem…they're more successful than our own :) ====================== Send us suggestions and comments to darwinsdeviations@gmail.com Intro/outro sampled from "Sequence (Mystery and Terror) 3" by Francisco Sánchez (@fanchisanchez) at pixabay.com Sound effects obtained from https://www.zapsplat.com Image Credit (Episode image is heavily edited, the image owner reserves all rights to their image, and is not affiliated with our podcast) SOURCES: Wikipedia: Prokaryote Wikipedia: Cyanobacteria Microbe Wiki: Oscillatoria Oscillatoria: Occurrence, Thallus Structure and Reproduction Oscillatoria – Classification , Occurrence , Structure and Reproduction AlgaeBase: Oscillatoria Vaucher ex Gomont, 1892 Nuernberg, Dennis & Mariscal, Vicente & Parker, Jamie & Mastroianni, Giulia & Flores, Enrique & Mullineaux, Conrad. (2014). Branching and intercellular communication in the Section V cyanobacterium Mastigocladus laminosus, a complex multicellular prokaryote. Molecular microbiology. 91. 10.1111/mmi.12506. Rani, V. & Ulagalanthaperumal, Elaya Perumal & Sonaimuthu, Palanivel. (2016). Morphology and taxonomy of Oscillatoria princeps Vaucher ex gomont (OSCILLATORIALES, OSCILLATORIACEAE). Indian Journal of Education and Information Management. 5. 1-5. Muhlsteinova, Radka & Hauer, Tomáš & Ley, Paul & Pietrasiak, Nicole. (2018). Seeking the true Oscillatoria: A quest for a reliable phylogenetic and taxonomic reference point. Preslia. 90. 10.23855/preslia.2018.151. Brahamsha, B. and D. Bhaya. “Motility in Unicellular and Filamentous Cyanobacteria.” (2013). Ridley, Christian & Faulkner, D & Haygood, Margo. (2005). Investigation of Oscillatoria spongeliae-Dominated Bacterial Communities in Four Dictyoceratid Sponges. Applied and environmental microbiology. 71. 7366-75. 10.1128/AEM.71.11.7366-7375.2005.

Mit Hilfe von spektroskopischen Messmethoden (Absorption, Circulardichroismus, Fluoreszenz) wurde die Entfaltung von Phycocyanin untersucht. Dabei diente der Chromophor als natürliche Sonde, zusätzlich wurde die Sekundärstruktur gemessen. Im ersten Teil der Arbeit wurden die Bedingungen der Untersuchungen festgelegt. Anschließend erfolgte die Entfaltung in steady-state Messungen mittels Harnstofftitration. Als drittes wurde die Kinetik der Entfaltung in 8 M Harnstoff untersucht. Daraus entwickelete sich eine Entfaltungsmodell, sowohl für das integrale Phycocyanin, wie auch für die Untereinheiten.

Die α-Untereinheit des Phycoerythrocyanins ist ein Chromoprotein, das eine Rolle bei der Photosynthese von Mastigocladus laminosus, einem Cyanobakterium, spielt. Dieses Protein besitzt einen seltenen Gallenfarbstoff als Chromophor, der nie in freier Form gefunden werden konnte. Daneben ist das Chromoprotein zu einer ausgeprägten reversiblen Photochemie fähig, die der Photochemie des Phytochroms ähnelt. Es konnte ein Rekonstitutionssystem etabliert werden, mit dessen Hilfe die Chromophorbindung aufgeklärt werden konnte. Für die korrekte Bindung des Chromophors ist dabei neben dem Apoprotein und einem Gallenfarbstoff ein neuartiges Enzym, eine sog. Lyase-Isomerase notwendig. Anhand von Rekonstitutionen mit chemisch modifizierten Chromophoren konnte mit Hilfe molekularbiologischer, spektroskopischer und chromatographischer Methoden auch ein Modell für den Mechanismus der Photochemie des Chromoproteins entwickelt werden.

Three building blocks of the antenna complexes of the cyanobacterium Westiellopsis prolifica were studied: PEC(X), which is similar to the α-subunit of phycoerythrocyanin (PEC), trimers of PEC and monomers derived from these by deaggregation with KSCN. The fit of the fluorescence decay curve of PEC(X) requires at least four exponentials, although it supposedly contains only one chromophore. The coherent anti-Stokes Raman scattering (CARS) spectra indicate that the heterogeneity observed is due to geometrical isomers, which are in part generated by photoinduced processes. A similar heterogeneity in chromophore structure and properties is also found in the monomers, where four exponentials are needed to fit the fluorescence decay curve. As in trimers, there is a long-lived, low-amplitude component, which can be assigned to impurities and/or oxidation products. The energy transfer time between the two phyocyanobilin chromophores in the β-subunit is about 500 ps; the lifetime of the fluorescing β-chromophore is 1.5 ns. The phycoviolobilin chromophore in the α-subunit adopts different geometries characterized by fluorescence lifetimes of about 240 and 800 ps. No evidence was found for energy transfer between the α-chromophore and the β-chromophores. This energy transfer occurs in trimers on a time scale of less than 20 ps; the energy transfer time between the two different types of β-chromophore is about 250 ps and the lifetime of the terminal emitter is about 1.5 ns. The excited state kinetics are therefore similar to those of PEC trimers from Mastigocladus laminosus, as are the CARS spectra, indicating a similar chromophore—protein arrangement. In comparison with phycocyanin, the ordering of the excited states of chromophores β84 and β155 may be changed. Although PEC trimers of Westiellopsis prolifica show almost as good a photostability as trimers of Mastigocladus laminosus, monomers are so photolabile that no CARS spectra could be recorded.

The excitation-energy transfer in C-phycocyanin (C-PC) trimers and monomers isolated from phycobilisomes of Mastigocladus laminosus has been studied by polarization femtosecond laser spectroscopy. Excitation with 70-fs pulses at 615 nm gave rise to a 500-fs energy-transfer process that was observed only in trimeric preparations. The rate of the process is in agreement with earlier calculated Förster energy transfer rates between neighbouring α-84 and β-84 chromophores of different monomeric subunits. This process is most clearly seen in the anisotropy decay kinetics. As a result of femtosecond excitation-energy transfer, the anisotropy relaxes from 0.4 to 0.23. The final anisotropy value is in fair agreement with the results of calculations based on the crystal structure and spectroscopic data of C-PC trimers. Our results support the conclusion that Förster energy transfer can occur between excitonically coupled chromophores.

Resonance-enhanced coherent anti-Stokes Raman spectra are recorded for monomers and trimers of phycocyanin from three different cyanobacteria: Westiellopsis prolifica, Mastigocladus laminosus and Spirulina platensis. It is shown that upon aggregation from monomer to trimer the electronic structures of both the α84 and β84 chromophores are changed. The spectra of the trimers originating from S. platensis and M. laminosus are very similar to each other, but distinctly different from the spectrum of W. prolifica.

Two phycoerythrocyanin (PEC) fractions have been obtained from the phycobilisomes of the cyanobac-terium Westiellopsis prolifica ARM 365. They have been characterized by absorption, fluorescence and circular dichroism spectroscopy. One of them is spectroscopically similar to a PEC trimer known from other organisms. Whereas efficient energy transfer from its violin (α-84) to the cyanin (β-84, 155) chromophores is efficient in the trimer (αβ it is impeded after dissociation to the monomer (α,β). A second fraction of PEC which we earlier termed PEC(X) (Maruthi Sai et al., Photochem. Photobiol. 55,119–124, 1992), exhibited the spectral properties similar to that of the α-subunit of PEC from Mastigocladus laminosus. With this highly photoactive fraction, the circular dichroism spectra of the violobilin chromophore in both photoreversible states were obtained.

The photochemical activities of phycoerythrocyanin α-subunits from Mastigocladus laminosus separated by isoelectric focusing were tested by irradiating at 500, 550, 577 and 600 nm. Two types of photoreversible photochromic responses have been characterized by absorption and absorption difference spectroscopy. Type I is the well-known absorption shift from 571 to 506 nm. Type II is a new response characterized by a line-broadening of the 570 nm absorption.

The core linker polypeptide Lc 8.9 was isolated from Mastigocladus laminosus and purified on a preparative scale. A method for the reconstitution of allophycocyanin (AP)—linker complexes from isolated polypeptides was developed. The complex (αAP(βAP)3 Lc 8.9 was reconstituted and compared to (αAPβAP) and (αAPβAP)3 by sucrose density gradient ultracentrifugation, absorption, fluorescence emission and circular dichroism spectroscopy. Differences in the spectra of reconstituted and of directly isolated AP complexes are discussed.

Persistent optical hole burning has been performed in the allophycocyanin band of phycobilisomes of Mastigocladus laminosus. The homogeneous transition line width has been obtained by a careful analysis of the hole-burning data. The dependence of the line width on temperature has been measured in the range 1.5-4.2 K. A lifetime-limited value of 1.08 A 0.21 GHz is obtained as a result of linear back extrapolation to T = 0 K. It corresponds to an energy transfer time of 147 f IS ps from allophycocyanin to the terminal emitters of the phycobilisome core.

The bilin chromophores of the α or β subunit of C-phycocyanin (PC) from Mastigocladus laminosus were modified, and subsequently recombined with the respective complementary unmodified chromophores. The modifications consisted of photobleaching (350 nm) or reversible reduction of the verdin- to rubin-type chromophore(s). Recombination led to heterodimers (αβ)1, but the heterohexameric aggregation state (αβ)3 could not be obtained with the modified chromophores. Autoxidation of the reduced α-84 chromophore in such a hybrid, which occurred on standing under aerobic conditions, induced reaggregation to heterohexamers. Chemical re-oxidation of the reduced chromophores did not produce reaggregation, and it was not promoted by a 22 kDa linker peptide fragment (Gottschalk et al., Photochem. Photobiol., 54 (1991) 283), which in unmodified samples stabilized heterohexameric aggregates. Binding of the mercurial p-chloromercury-benzenesulphonate to the single free cysteine of PC near (approximately 0.4 nm) the β-84 chromophore had only a moderately destabilizing effect on the heterohexamer (αβ)3. It was concluded that the intact chromophore structure is an important factor determining the quaternary structure of biliproteins. The tendency of heterohexamer destabilization is related to the situation in phycoerythrocyanin, where photoisomerization of the violobilin chromophore of the α subunit near the heterodimer—heterodimer contact region is also responsible for aggregate destabilization (Siebzehnrübl et al., Photochem. Photobiol., 46 (1989) 753).

Ultrafast energy-transfer processes in allophycocyanin (APC) trimers from Mastigocladus laminosus have been examined by a femtosecond absorption technique. Isotropic absorption recovery kinetics with τ=440±30 fs were observed in APC trimers at 615 nm. In APC monomers such a fast process was not observed. The anisotropy in both samples was constant and close to 0.4 during the first few picoseconds. The results are consistent with a model of the APC trimer in which the two APC chromophores have different absorption spectra with maxima about 600 and 650 nm. The transfer of energy from the 600 nm chromophore to the 650 nm chromophore occurs in 440 fs and is dominated by the Förster dipole—dipole energy-transfer mechanism.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2347/ http://epub.ub.uni-muenchen.de/2347/1/2347.pdf Schneider, Siegfried; Wokusch, T.; Tiltscher, H.; Fischer, R.; Scheer, Hugo Schneider, Siegfried; Wokusch, T.; Tiltscher, H.; Fischer, R. und Scheer, Hugo (1991): UV-VIS absorption spectra at high pressure of C-phycocyanin and allophycocyanin from Mastigocladus laminosus. In: Zeitschrift für Naturforschung C, Vol. 46c: pp. 717-724.

The α- and β-subunits of C-phycocyanin from Mastigocladus laminosus were prepared according to revised procedures. Both subunits are isolated as dimers, which can be dissociated into monomers with detergent mixtures. The fluorescence decay kinetics are similar for the respective monomers and dimers. In no case could they be fitted by only one (α-subunit) or two exponentials (β-subunit) which are predicted by theory for samples with a unique chromophore—protein arrangement containing one and two chromophores, respectively. It is suggested that there exists a heterogeneity among the chromophores of the subunits, which may persist in the highly aggregated complexes present in cyanobacterial antennas.

Native PEC from the cyanobacterium, Mastigocladus laminosus, and its isolated α-subunit show photoreversibly photochromic reactions with difference-maxima around 502 and 570 nm in the spectral region of the α-84 phycoviolobilin chromophore. (b) Native PEC and its β-subunit show little if any reversible photochemistry in the 600–620 nm region, where the phycocyanobilin chromophores on the β-subunit absorb maximally, (c) Reversible photochemistry is retained in ureadenatured PEC at pH = 7.0 or pH ≤ 3. The difference maxima are shifted to 510 and 600 nm, and the amplitudes are decreased. An irreversible absorbance increase occurs around 670 nm (pH ≤ 3). (d) The amplitude of the reversible photoreaction difference spectrum is maximum in the presence of 4–5 M urea or 1 M KSCN, conditions known to dissociate phycobiliprotein aggregates into monomers. At the same time, the phycocyanobilin chromophore(s) are bleached irreversibly, (e) The amplitude becomes very small in high aggregates, e.g. in phycobilisomes. (f) In a reciprocal manner, the phototransformation of native PEC leads to a reversible shift of its aggregation equilibrium between trimer and monomer. The latter is favored by orange, the former by green light, (g) It is concluded that the phycoviolobilin chromophore of PEC is responsible for reversible photochemistry in PEC, and that there is not only an influence of aggregation state on photochemistry, but also vice versa an effect of the status of the chromophore on aggregation state. This could constitute a primary signal in the putative function as sensory pigment, either directly, or indirectly via the release of other polypeptides, via photodynamic effects, or the like.

We have investigated by picosecond absorption experiments how the size of C-phycocyanin aggregates from Mastigocladus laminosus influences the excitation energy transfer kinetics. Going from C-phycocyanin monomers to trimers the lifetime of the faster energy transfer component decreased from 57 ± 4 to 27 ± 4 ps over most of the wavelength range (580–645 nm) studied. This change was interpreted as the opening of fast transfer channels (α-84 → β-84 and/or β-84 → β-84) between two adjacent monomers in the trimeric unit. The 57 ps lifetime is probably due mainly to the β-155 → β-84 energy transfer step. The intermediate lifetime decreased from about 300 ps in the monomer to 100–120 ps in the trimer. The former is believed to be dominated by the equilibration process α-84 a3 β-84, while the latter probably represents the time required for the excitation energy to reach thermodynamic equilibrium within the trimer. The lifetime of the longest components was about 1 ns in both systems. This indicates that the chromophores in these C-phycocyanin complexes are more exposed to non-radiative processes (like, for instance, isomerization) compared to the chromophores in intact phycobilisomes, where this lifetime typically is about 1.8 ns. The anisotropy relaxation closely followed the isotropic lifetimes in both systems. The anisotropy after the initial fast relaxation, r(∞), was 0.29 ± 0.04 in monomers and decreased to 0.15 ± 0.03 in trimers. Measurements of the steady-state fluorescence excitation anisotropy gave the same results within the experimental error.

Calculations of excitation transfer rates among the chromophores of C-phycocyanin using the Förster inductive resonance transfer mechanism have been carried out using the new coordinates for the position and orientation of the chromophores (Schirmer, T., Bode, W. and Huber, R. (1987) J. Mol. Biol. 196, 677–695). Several of the rate constants are significantly altered from the results of our calculations using the previously published coordinates (Sauer, K., Scheer, H. and Sauer, P. (1987) Photochem. Photobiol. 46, 427–440). In particular, for the (αβ)3-trimers of Mastigocladus laminosus or for the (αβ)3-trimers or the (αβ)6-hexamers of Agmenellum quadruplicatum, the new calculations predict excited state relaxation components with exponential time constants shorter than 1 ps. In fact, some of the interchromophore interactions are so strong that exciton coupling is probably the relevant mechanism of interaction. The largest exciton energy is calculated to be about 56 cm−1, for the interaction between the adjacent α84 and β84 chromophores of neighboring monomer units within the (αβ)3-trimers or (αβ)6-hexamers. An energy transfer model invoking a combination of pairwise exciton formation followed by slower Förster transfer steps is described.

Fri, 1 Jan 1988 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2229/ http://epub.ub.uni-muenchen.de/2229/1/2229.pdf Fischer, R.; Siebzehnrübl, S.; Scheer, Hugo Scheer, Hugo und Schneider, S. (Hrsg.) (1988): C-phycocyanin from Mastigocladus laminosus. Chromophore assignment in higher aggregates by cystein modification. Photosynthetic light-harvesting systems, 12. - 16. Oktober 1987 , Deutschland. Biologie

Excitation energy transfer in C-phycocyanin is modeled using the Forster inductive resonance mechanism. Detailed calculations are carried out using coordinates and orientations of the chromophores derived from X-ray crystallographic studies of C-phycocyanin from two different species (Schirmer et al, J. Mol. Biol. 184, 257–277 (1985) and ibid., 188, 651-677 (1986)). Spectral overlap integrals are estimated from absorption and fluorescence spectra of C-phycocyanin of Mastigocladus laminosus and its separated subunits. Calculations are carried out for the β-subunit, αβ-monomer, (αβ)3-trimer and (αβ)0-hexamer species with the following chromophore assignments: β155 = 's’(sensitizer), β84 =‘f (fluorescer) and α84 =‘m’(intermediate):]:. The calculations show that excitation transfer relaxation occurs to 3=98% within 200 ps in nearly every case; however, the rates increase as much as 10-fold for the higher aggregates. Comparison with experimental data on fluorescence decay and depolarization kinetics from the literature shows qualitative agreement with these calculations. We conclude that Forster transfer is sufficient to account for all of the observed fluorescence properties of C-phycocyanin in aggregation states up to the hexamer and in the absence of linker polypeptides.

Thu, 1 Jan 1987 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2227/ http://epub.ub.uni-muenchen.de/2227/1/2227.pdf Siebzehnrübl, S.; Fischer, R.; Scheer, Hugo Siebzehnrübl, S.; Fischer, R. und Scheer, Hugo (1987): Chromophore assignment in C-phycocyanin from Mastigocladus laminosus. In: Zeitschrift für Naturforschung C, Vol. 42c: pp. 258-262. Biologie

The excited state kinetics of trimeric C-phycocyanin from Mastigocladus laminosus has been measured as a function of the emission and excitation wavelength by the single-photon timing technique with picosecond resolution and simultaneous data analysis. A fast decay component of 22 ps (C-phycocyanin with linker peptides) and 36 ps (C-phycocyanin lacking linker peptides) is attributed to efficient energy transfer from sensitizing to fluorescing chromophores. At long detection wavelengths the fast decay components are found to turn into a rise term. This finding further corroborates the concept of intramolecular energy transfer. Previous reports on the conformational heterogeneity of the chromophores and/or proteins in C-phycocyanin are confirmed. Our data also provide indications for the importance of the uncoloured linker peptides for this heterogeneity.

Tue, 1 Jan 1985 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2163/ http://epub.ub.uni-muenchen.de/2163/1/2163.pdf John, Wolfhart; Fischer, R.; Siebzehnrübl, S.; Scheer, Hugo John, Wolfhart; Fischer, R.; Siebzehnrübl, S. und Scheer, Hugo (1985): C-phycocyanin from Mastigocladus laminosus. Isolation and properties of subunits and small aggregates. In: Michel-Beyerle, Maria E. (Hrsg.), Antennas and reaction centers of photosynthetic bacteria : structure, interactions, and dynamics ; proceedings of an internat. workshop, Feldafing, Bavaria, F.R.G., March 23 - 25, 1985. Springer: Berlin u.a., pp. 17-25. Biologie

Tue, 1 Jan 1985 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2169/ http://epub.ub.uni-muenchen.de/2169/1/2169.pdf Schneider, Siegfried; Geiselhart, P.; Mindl, T.; Dörr, F.; John, Wolfhart; Fischer, R.; Scheer, Hugo Schneider, Siegfried; Geiselhart, P.; Mindl, T.; Dörr, F.; John, Wolfhart; Fischer, R. und Scheer, Hugo (1985): Picosecond time-resolved, polarized fluorescence decay of phycobilisomes and constituent biliproteins isolated from Mastigocladus laminosus. In: Michel-Beyerle, Maria E. (Hrsg.), Antennas and reaction centers of photosynthetic bacteria : structure, interactions, and dynamics ; proceedings of an internat. workshop, Feldafing, Bavaria, F.R.G., March 23 - 25, 1985. Springer: Berl

Sun, 1 Jan 1984 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2911/ http://epub.ub.uni-muenchen.de/2911/1/2911.pdf Hefferle, P.; Geiselhart, P.; Mindl, T.; Schneider, Siegfried; John, Wolfhart; Scheer, Hugo Hefferle, P.; Geiselhart, P.; Mindl, T.; Schneider, Siegfried; John, Wolfhart und Scheer, Hugo (1984): Time-resolved polarized fluorescence of C-phycocyanin and its subunits from Mastigocladus laminosus. In: Zeitschrift für Naturforschung C, Vol. 39c: pp. 606-616.