Raman Spectroscopic Insights into the Chemical Gradients within the Wound Plug of the Green Alga <i>Caulerpa taxifolia</i>

Weissflog, Ina; Grosser, Katharina; Bräutigam, Maximilian; Dietzek, Benjamin; Pohnert, Georg; Popp, Juergen

doi:10.1002/cbic.201300013

Cited by 9 publications

(12 citation statements)

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“…The Raman images of cells show that the distribution of lipids and proteins vary during cell division cycles. Because of these capabilities, recent reports reveal the distribution of secondary metabolites—pigment in plants [25] and green macroalgae [26]—using FT-Raman microspectroscopy. Since secondary metabolites such as antibiotics generally have diverse and distinctive chemical structures, we postulated that Raman imaging has the potential to distinguish antibiotics from other biomolecules in living cells without labeling or extraction.…”

Section: Introductionmentioning

confidence: 99%

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

et al. 2014

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The study of spatial distribution of secondary metabolites within microbial cells facilitates the screening of candidate strains from marine environments for functional metabolites and allows for the subsequent assessment of the production of metabolites, such as antibiotics. This paper demonstrates the first application of Raman microspectroscopy for in situ detection of the antifungal antibiotic amphotericin B (AmB) produced by actinomycetes—Streptomyces nodosus. Raman spectra measured from hyphae of S. nodosus show the specific Raman bands, caused by resonance enhancement, corresponding to the polyene chain of AmB. In addition, Raman microspectroscopy enabled us to monitor the time-dependent change of AmB production corresponding to the growth of mycelia. The Raman images of S. nodosus reveal the heterogeneous distribution of AmB within the mycelia and individual hyphae. Moreover, the molecular association state of AmB in the mycelia was directly identified by observed Raman spectral shifts. These findings suggest that Raman microspectroscopy could be used for in situ monitoring of antibiotic production directly in marine microorganisms with a method that is non-destructive and does not require labeling.

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Section: Introductionmentioning

confidence: 99%

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

et al. 2014

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“…In wound plugs of both species, compared with intact algal tissue, new bands appeared between 1500 and 1700 cm -1 (Figure 3(E)), as did a band at 1186 cm -1 (Figures 4(A) and 4(B)). In C. taxifolia, these signals appeared at 1556, 1582 and 1610 cm -1 (Weissflog et al 2013), while corresponding bands in the wound plug of C. prolifera were found at 1556, 1572 and 1627 cm -1 . These signals cannot be assigned to specific chemical structures but can be considered as characteristics of the wound plug of the algae.…”

Section: Resultsmentioning

confidence: 94%

“…Around 2187 cm -1 , bands of the carbon triple bond stretching vibration could be observed in both species (Figure 3(D)). These are characteristic of caulerpenyne and caulerpenyne derivatives, which are involved in protein crosslinking (Figure 1) (Weissflog et al 2013). …”

Section: Resultsmentioning

confidence: 99%

“…The comparative study presented here follows up a first report on the wound plug formation of C. taxifolia (Weissflog et al 2013). In this previous study, it has been reported that the region around the wound site of C. taxifolia consists of four chemically distinct zones.…”

Section: Introductionmentioning

confidence: 86%

“…A possible chemical difference between the wound plugs of both Caulerpa species is difficult to prove by common analytical methods, as the material is insoluble and the constituents are of high molecular weight (Adolph et al 2005). Therefore, we reverted to Raman spectroscopy to obtain chemical information about different parts of the wound plug without destruction of the sample (Weissflog et al 2013). This spectroscopic method requires minimum sample preparation, and no disruption of the wound plug occurs due to stress during measurements (Walter et al 2010, Grosser et al 2012.…”

Section: Introductionmentioning

confidence: 99%

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Wound plug chemistry and morphology of two species of Caulerpa – a comparative Raman microscopy study

Grosser¹,

Weissflog²,

Dietzek³

et al. 2014

Botanica Marina

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Caulerpa spp. form a polymer wound plug that seals their giant cells after mechanical injury, in order to prevent fatal loss of cell material. Initial mass spectrometry and Raman spectroscopy investigations revealed the involvement of the secondary metabolite caulerpenyne in wound sealing polymer formation. In this work, we introduce a comparative Raman spectroscopic study of the wound plug formation in the invasive Caulerpa taxifolia (Valh) Agardh, 1817 and the non-invasive Caulerpa prolifera J.V. Lamour. In both species, the enzymatic transformation of the main secondary metabolite caulerpenyne plays a key role in wound plug formation. An accumulation of caulerpenyne is observed at the inner border of the wound plugs. Furthermore, caulerpenyne and products resulting from its enzymatic transformation and co-polymerization with proteins are found within the wound plug. However, there are significant differences in the chemistry of the wound plugs between the species. The Raman spectra reveal a zonation of the wound plug of C. taxifolia into four chemically distinguishable regions, while that of C. prolifera consists of only three regions with specific chemical composition. These results explain differences in the morphology of the wound plug in both species.

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Functionalized Bis‐enol Acetates as Specific Molecular Probes for Esterases

et al. 2013

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Esterases and lipases are hydrolytic enzymes with a characteristic a/b-hydrolase fold and a catalytic Ser/His/Asp triad at the active site. [1] Both enzyme classes make or break ester bonds, but whereas esterases act on water-soluble substrates, lipases hydrolyze ester bonds of hydrophobic lipids at the water/lipid interface. [2] These enzymes have fundamental importance in metabolic and regulative processes, and have been considered as attractive targets for, for example, anti-inflammatory [3] or anti-obesity drugs. [4] Besides their central role in metabolism, lipases and esterases are also very important in industrial applications, and have been widely used in organic synthesis. [5] There is substantial interest in the specific identification and monitoring of esterases or lipases in biological samples, and the first approaches towards activity-based proteomics of these enzymes have been introduced.[6] Most successful was the development of alkylphosphonic acid esters that react irreversibly with the nucleophilic serine in the active site of lipases and esterases. [7] If such reagents are equipped with fluorescent reporter tags, the irreversible binding to the serin of the catalytic triad offers the opportunity for specific labeling. [6,8] Some specificity was reached by variation in the polarity of the alkylphosphonic acid esters, but the selectivity was rather poor. [9] Fluorescently labeled p-nitrophenol esters of alkylphosphonates with two selector groups of different polarity and stereochemistry were more suitable to discriminate lipolytic and esterolytic activities, [8] and a versatile library of alkylphosphonic acid esters is available for the investigation of lipolytic enzymes. [10] Here we follow a general novel approach for esterase labeling by exploiting nature's inventory for the in situ generation of protein reactive groups, thereby applying current concepts of activity-based protein profiling [11] towards the ester hydrolytic enzymes.The introduced probe design is inspired by the natural product caulerpenyne (1), a compound that mediates rapid wound closure in the siphonous green alga Caulerpa taxifolia. [12] This alga consists of one giant cell that can reach several meters in length. It therefore needs to seal wounds within seconds to avoid leakage of the cytoplasm and cell death. [13] Wound-sealing polymer formation is initiated by transformation of the 1,4bis-enol acetate structural unit of 1 by alga esterases into the reactive conjugated 1,4-bis-aldehyde oxytoxin 2 (2), which directly undergoes covalent reaction with proteins to form adducts or polymers (Scheme 1). [12] We reasoned that this esterase-mediated release of a highly protein-reactive metabolite might be exploited for the development of selective esterasereactive probes. As only the acetyl-functionalized part of the metabolite is involved in the covalent reactions of polymerization we decided to replace the dienyne terminus with a linker for flexible functionalization (Scheme 1).In analogy to the total synthesis of 1 by Commeir...

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Raman Spectroscopic Insights into the Chemical Gradients within the Wound Plug of the Green Alga Caulerpa taxifolia

Cited by 9 publications

References 27 publications

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

Wound plug chemistry and morphology of two species of Caulerpa – a comparative Raman microscopy study

Functionalized Bis‐enol Acetates as Specific Molecular Probes for Esterases

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