Total Syntheses

Mayer, H.; Isler, O.

doi:10.1007/978-3-0348-5831-1_6

Cited by 38 publications

(14 citation statements)

References 299 publications

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“…The β‐carotene can be obtained from natural sources like vegetables, fruits, microalgae and the fungus Blakeslea (Dufosse et al. 2005) or produced by total syntheses (Mayer and Isler 1971). In terms of isomers composition, synthetic β‐carotene contains only the all‐ trans isomer (Fig.…”

Section: Applicationsmentioning

confidence: 99%

Dunaliellabiotechnology: methods and applications

Tafreshi

Shariati

2009

Journal of Applied Microbiology

276

134

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Summary The microalga Dunaliella salina is the best commercial source of natural β‐carotene. Additionally, different species of Dunaliella can accumulate significant amounts of valuable fine chemicals such as carotenoids, glycerol, lipids, vitamins, minerals and proteins. They also have a large potential for biotechnological processes such as expressing of foreign proteins and treatment of wastewater. In this review, we discussed several biotechnological aspects of the mass cultivation of D. salina like strain selection, carotenoid induction, culture conditions, culture systems and downstream processes. We also discuss several traditional and new applications of the genus.

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Section: Applicationsmentioning

confidence: 99%

Dunaliellabiotechnology: methods and applications

Tafreshi

Shariati

2009

Journal of Applied Microbiology

276

134

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“…(Fig. 1) was prepared by conventional Wittig reaction between (␤-ionylideneethyl) triphenylphosphorane (26) and ethyl 3-methyl-4-oxobutanoate; the latter was obtained by catalytic reduction of ethyl 3-methyl-4-oxocrotonate (Fluka Chemical Co.). Diisobutylaluminum hydride reduction of the resulting isomeric mixture of ethyl 13,14-dihydroretinoate gave analog I, which was further purified by HPLC (8).…”

mentioning

confidence: 99%

Spectral Tuning in Bacteriorhodopsin in the Absence of Counterion and Coplanarization Effects

Yan

Spudich

Mazur

et al. 1995

Journal of Biological Chemistry

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The basis for wavelength regulation in bacteriorhodopsin (BR) and retinylidene proteins in general has been studied for decades but is still only partially understood. Here we report the preparation and spectroscopic characterization of BR analogs aimed at investigating the existence of spectral tuning mechanisms other than the two widely accepted mechanisms, weakened counterion interactions and ring/chain coplanarization. We synthesized two novel retinal analogs containing a saturated 13-14 bond, which interrupts the interaction of the protein counterions with the chromophore conjugation system. Furthermore, one of the analogs has a planar polyene system so that the contribution to the red shift of BR by retinal ring/chain coplanarization is also absent. We incorporated these analogs into bacterioopsin and discovered a sizable amount of red shift, which can be accounted for by interactions between the polar or polarizable groups of the protein and the retinal polyene chain. Our results suggest that the wavelength regulation in BR is achieved by synergistic chromophore/protein interactions including ring/ chain coplanarization, excited state stabilization by polar or polarizable protein side chains located along the polyene chain, and weakened counterion interactions near the Schiff base positive charge. Bacterioopsin (BO)1 tunes the absorption maximum ( max ) of a retinal protonated Schiff base (PSB) from 440 nm in methanol to 568 nm in bacteriorhodopsin (BR). The mechanism of wavelength regulation in BR and in retinylidene proteins in general has been a subject of intensive investigation. Nakanishi et al.(1) introduced the term opsin shift (OS) to refer to the energy difference (in cm Ϫ1

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“…2. Double Wittig reactions have been used extensively in carotenoid synthesis (14). Lithiation of 4-methylpyridine with BuLi followed by reaction with ClPPh2 and subsequent oxidation with 02 gave the phosphine oxide 3 (mp, 212'C; 70% yield).…”

Section: Methodsmentioning

confidence: 99%

Molecular devices: Caroviologens as an approach to molecular wires—synthesis and incorporation into vesicle membranes

Arrhenius

Blanchard‐Desce

Dvolaïtzky

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

124

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Molecular wires, which would allow electron flow to take place between different components, are important elements in the design of molecular devices. An approach to such species would be molecules possessing an electron-conducting conjugated chain, terminal electroactive polar groups, and a length sufficient to span a lipid membrane. To this end, bispyridinium polyenes of different lengths have been synthesized and their incorporation into the bilayer membrane of sodium dihexadecyl phosphate vesicles has been studied. Since they combine the features of carotenoids and of viologens, they may be termed caroviologens. Vesicles containing the caroviologen whose length approximately corresponds to the thickness of the sodium dihexadecyl phosphate bilayer display temperature-dependent changes of its absorption spectrum reflecting the gel --liquidcrystal phase transition of the membrane. The data agree with a structural model in which the caroviologens of sufficient length span the bilayer membrane, the pyridinium sites being close to the negatively charged outer and inner surfaces of the sodium dihexadecyl phosphate vesicles and the polyene chain crossing the lipidic interior of the membrane. These membranes may now be tested in processes in which the caroviologen would function as a continuous, transmembrane electron channel-i.e., as a molecular wire. Various further developments may be envisaged along these lines.Molecular devices may be defined as structurally organized and functionally integrated chemical systems built into supramolecular architectures. The development of such devices requires the design of molecular components performing a given function (e.g., photoactive, electroactive, ionoactive, thermoactive, or chemoactive) and suitable for assembly into an organized array. A major requirement is that these components and the devices that they build up should perform their function(s) at the molecular and supramolecular (1) levels, as distinct from the level of the bulk material.

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Total Syntheses

Cited by 38 publications

References 299 publications

Dunaliellabiotechnology: methods and applications

Dunaliellabiotechnology: methods and applications

Spectral Tuning in Bacteriorhodopsin in the Absence of Counterion and Coplanarization Effects

Molecular devices: Caroviologens as an approach to molecular wires—synthesis and incorporation into vesicle membranes

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