Naturally Occurring Organohalogen Compounds

Gribble, Gordon W.

doi:10.1021/ar9701777

Cited by 589 publications

(274 citation statements)

References 107 publications

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“…214 The diterpenes discussed in this section are all brominated and the Br-substitution is restricted to C 15 , while C 16 is oxygenated. Another feature of these derivatives is the presence of a double bond at C 9 (11) , with only one exception, compound 314, which has this functional group at C 7 . 212 4.3.4.…”

Section: Halogenated Diterpenesmentioning

confidence: 99%

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

et al. 2013

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Section: Halogenated Diterpenesmentioning

confidence: 99%

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

et al. 2013

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“…Chlorinated organic compounds have natural and anthropogenic sources and are represented in nearly every organic chemical class [1]. Much fundamental interest is directed at the underlying reaction chemistry of the C-Cl bond [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE) Reductive Dehalogenation

et al. 2014

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Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (bio)chemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE) dehalogenation was investigated. Selective biotransformation reactions (i) of tetrachloroethene (PCE) to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii) of TCE to cis-1,2-dichloroethene (cis-DCE) in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were −19.0‰ ± 0.9‰ (PCE) and −12.2‰ ± 1.0‰ (TCE) (95% confidence intervals). Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (−5.0‰ ± 0.1‰) and TCE (−3.6‰ ± 0.2‰). In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by −16.3‰ ± 1.4‰ (standard error)) than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average OPEN ACCESSMolecules 2014, 19 6451 isotope effect of −2.4‰ ± 0.3‰ and the product chloride an isotope effect of −6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals). A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect). These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition). This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I) or single electron transfer as reductive dehalogenation mechanisms.

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“…Halogenated compounds are found in a small number of taxonomically widespread flowering plants, as well as in bacteria, fungi, and marine algae, 22 and halogenase genes have been cloned from bacteria and have been shown to be functional in transgenic alkaloid-producing Catharanthus roseus …”

Section: Disclosure Of Conflicts Of Interestmentioning

confidence: 99%

A mutation affecting the synthesis of 4-chloroindole-3-acetic acid

Ross

Tivendale

Davidson

et al. 2012

Plant Signaling & Behavior

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Evidence for the IPyA pathway in pea seeds comes from metabolism experiments with labeled compounds, the isolation of genes, and the effects of a mutation in one of those genes.2 Pea seeds are an excellent system for studying the metabolism of potential auxin intermediates. They are large, and labeled compounds can be injected into the seeds either in situ or after they are excised and placed in vitro. Typically, potential intermediates are injected at the liquid endosperm stage, and their subsequent metabolism determined by mass spectrometry. Additional compounds are injected into separate seeds as controls. For example, to test whether the tryptamine pathway operates in pea seeds, (see Fig. 1) labeled tryptamine was injected. Labeled tryptophan was injected into separate control seeds.3 Label was detected in IAA in the latter but not the former case, indicating that tryptamine is not an intermediate between tryptophan and IAA in this system. The lack of conversion of tryptamine to IAA cannot be attributed to wounding caused by the injection, because tryptophan was converted to IAA. Metabolism experiments also ruled out the indole-3-acetamide pathway (see Fig. 1), 2 while a fourth tryptophan-dependent pathway, via indole-3-acetaldoxime (see Fig. 1), is thought not to operate outside the Brassicaceae. When it became clear that the tryptamine pathway does not operate in pea seeds 3 (although it can operate in roots 5 ), we decided to investigate the IPyA pathway. We cloned three aminotransferase genes from pea and showed that two of the encoded enzymes convert tryptophan to IPyA, which is then converted in some way to IAA.2 In pea seeds IAA is the most abundant auxin traditionally, schemes depicting auxin biosynthesis in plants have been notoriously complex. they have involved up to four possible pathways by which the amino acid tryptophan might be converted to the main active auxin, indole-3-acetic acid (iaa), while another pathway was suggested to bypass tryptophan altogether. it was also postulated that different plants use different pathways, further adding to the complexity. in 2011, however, it was suggested that one of the four tryptophan-dependent pathways, via indole-3-pyruvic acid (iPya), is the main pathway in Arabidopsis thaliana, 1 although concurrent operation of one or more other pathways has not been excluded. We recently showed that, for seeds of Pisum sativum (pea), it is possible to go one step further.2 our new evidence indicates that the iPya pathway is the only tryptophan-dependent iaa synthesis pathway operating in pea seeds. We also demonstrated that the main auxin in developing pea seeds, 4-chloroindole-3-acetic acid (4-Cl-iaa), which accumulates to levels far exceeding those of iaa, is synthesized via a chlorinated version of the iPya pathway.

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Naturally Occurring Organohalogen Compounds

Cited by 589 publications

References 107 publications

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE) Reductive Dehalogenation

A mutation affecting the synthesis of 4-chloroindole-3-acetic acid

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