Publications by authors named "Tim Harig"

4 Publications

  • Page 1 of 1

Identification and composition of clasper scent gland components of the butterfly Heliconius erato and its relation to mimicry.

Chembiochem 2021 Sep 21. Epub 2021 Sep 21.

University of Cambridge Central Science Library: University of Cambridge, Department of Zoology, UNITED KINGDOM.

The butterfly Heliconius erato occurs in various mimetic morphs. The male clasper scent gland releases an anti-aphrodisiac pheromone and additionally contains a complex mixture of up to 350 components, varying between individuals. In 114 samples of five different mimicry groups and their hybrids 750 different compounds were detected by gas chromatography/mass spectrometry (GC/MS). Many unknown components occurred, which were identified using their mass spectra, gas chromatography/infrared spectroscopy (GC/IR)-analyses, derivatization and synthesis. Key compounds proved to be various esters of 3-oxohexan-1-ol and (Z)-3-hexen-1-ol with (S)-2,3-dihydrofarnesoic acid, accompanied by a large variety of other esters with longer terpene acids, fatty acids and various alcohols. In addition, linear terpenes with up to seven uniformly connected isoprene units occur, e. g. farnesylfarnesol. A large number of the compounds have not been reported before from nature. A discriminant analyses of principal components of the gland contents showed that the iridescent mimicry group differs strongly from the other, mostly also separated, mimicry groups. Comparison with data from other species indicated that Heliconius recruits different biosynthetic pathways in a species-specific manner for semiochemical formation.
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http://dx.doi.org/10.1002/cbic.202100372DOI Listing
September 2021

Bacterial-induced pH shifts link individual cell physiology to macroscale collective behavior.

Proc Natl Acad Sci U S A 2021 Apr;118(14)

Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel;

Bacteria have evolved a diverse array of signaling pathways that enable them to quickly respond to environmental changes. Understanding how these pathways reflect environmental conditions and produce an orchestrated response is an ongoing challenge. Herein, we present a role for collective modifications of environmental pH carried out by microbial colonies living on a surface. We show that by collectively adjusting the local pH value, spp., specifically, regulate their swarming motility. Moreover, we show that such pH-dependent regulation can converge with the carbon repression pathway to down-regulate flagellin expression and inhibit swarming in the presence of glucose. Interestingly, our results demonstrate that the observed glucose-dependent swarming repression is not mediated by the glucose molecule per se, as commonly thought to occur in carbon repression pathways, but rather is governed by a decrease in pH due to glucose metabolism. In fact, modification of the environmental pH by neighboring bacterial species could override this glucose-dependent repression and induce swarming of spp. away from a glucose-rich area. Our results suggest that bacteria can use local pH modulations to reflect nutrient availability and link individual bacterial physiology to macroscale collective behavior.
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http://dx.doi.org/10.1073/pnas.2014346118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040824PMC
April 2021

Extending the Salinilactone Family.

Chembiochem 2020 06 10;21(11):1629-1632. Epub 2020 Mar 10.

Institut für Organische Chemie, TU Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.

Five new members of the salinilactone family, salinilactones D-H, are reported. These bicyclic lactones are produced by Salinispora bacteria and display extended or shortened alkyl side chains relative to the recently reported salinilactones A-C. They were identified by GC/MS, gas chromatographic retention index, and comparison with synthetic samples. We further investigated the occurrence of salinilactones across six newly proposed Salinispora species to gain insight into how compound production varies among taxa. The growth-inhibiting effect of this compound family on multiple biological systems including non-Salinispora actinomycetes was analyzed. Additionally, we found strong evidence for significant cytotoxicity of the title compounds.
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http://dx.doi.org/10.1002/cbic.201900764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317194PMC
June 2020

Nitrogen-Containing Volatiles from Marine Salinispora pacifica and Roseobacter-Group Bacteria.

J Nat Prod 2017 12 1;80(12):3289-3295. Epub 2017 Dec 1.

Institute of Organic Chemistry, Technische Universität Braunschweig , Hagenring 30, 38106 Braunschweig, Germany.

Bacteria can produce a wide variety of volatile compounds. Many of these volatiles carry oxygen, while nitrogen-containing volatiles are less frequently observed. We report here on the identification and synthesis of new nitrogen-containing volatiles from Salinispora pacifica CNS863 and explore the occurrence in another bacterial lineage, exemplified by Roseobacter-group bacteria. Several compound classes not reported before from bacteria were identified, such as dialkyl ureas and oxalamides. Sulfinamides have not been reported before as natural products. The actinomycete S. pacifica CNS863 produces, for example, sulfinamides N-isobutyl- and N-isopentylmethanesulfinamide (5, 6), urea N,N'-diisobutylurea (16), and oxalamide N,N'-diisobutyloxalamide (17). In addition, new imines such as (E)-1-(furan-2-yl)-N-(2-methylbutyl)methanimine (8) and (E)-2-((isobutylimino)methyl)phenol (13) were identified together with several other imines, acetamides, and formamides. Some of these compounds including the sulfinamides were also released by the Roseobacter-group bacteria Roseovarius pelophilus G5II, Pseudoruegeria sp. SK021, and Phaeobacter gallaeciensis BS107, although generally fewer compounds were detected. These nitrogen-containing volatiles seem to originate from biogenic amines derived from the amino acids valine, leucine, and isoleucine.
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http://dx.doi.org/10.1021/acs.jnatprod.7b00789DOI Listing
December 2017
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