Heidy Herrera - Academia.edu (original) (raw)

Papers by Heidy Herrera

<p>Mass spectra of (A) natural (7<i>Z</i>,10<i>Z</i>)-7,10-hexadeca... more <p>Mass spectra of (A) natural (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal, (B) D₁₁-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal from glands treated with D₁₁-linoleic acid, (C) D₃-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal from glands treated with D₃-stearic acid.</p

<p>Gas chromatograms of hexane extracts of (A) a pheromone gland treated with DMSO only and... more <p>Gas chromatograms of hexane extracts of (A) a pheromone gland treated with DMSO only and (B) a pheromone gland treated with a solution of D₁₁-linoleic acid in DMSO. Z7,Z10-16:Ald = (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal.</p

<p>Methyl esters of fatty acids identified in a methylated chloroform extract of the pherom... more <p>Methyl esters of fatty acids identified in a methylated chloroform extract of the pheromone gland of <i>Chilecomadia valdiviana</i>.</p

<p>Mass spectra of (A) unlabeled methyl (7<i>Z</i>,10<i>Z</i>)-7,10... more <p>Mass spectra of (A) unlabeled methyl (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienoate from methylated pheromone gland extracts, (B) methyl D₁₁-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienoate from pheromone glands treated with D₁₁-linoleic acid.</p

<p>Titers of unlabeled and labeled Z7,Z10-16:Ald in pheromone glands of <i>Chilecomad... more <p>Titers of unlabeled and labeled Z7,Z10-16:Ald in pheromone glands of <i>Chilecomadia valdiviana</i> females, which were treated with isotope-labeled fatty acids.</p

<p>(A) Total ion chromatogram (TIC) of a hexane extract of a pheromone gland treated with D... more <p>(A) Total ion chromatogram (TIC) of a hexane extract of a pheromone gland treated with D₃-stearic acid. Z7,Z10-16:Ald = (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal, Z7-16:Ald = (<i>Z</i>)-7-hexadecenal, Z9-16:Ald = (<i>Z</i>)-9-hexadecenal. (B) Mass chromatograms show the elution of the isotope-labeled pheromone compound (<i>m/z</i> 239, 196, and 182) slightly earlier than the non-labeled compound (<i>m/z</i> 236, 193, and 179).</p

<p>The linoleic acid may be of dietary origin or may be synthesized from stearic acid (dash... more <p>The linoleic acid may be of dietary origin or may be synthesized from stearic acid (dashed arrow).</p

Journal of Chemical Ecology, 2017

Field experiments were carried out to study responses of male moths of the carpenterworm, Chileco... more Field experiments were carried out to study responses of male moths of the carpenterworm, Chilecomadia valdiviana (Lepidoptera: Cossidae), a pest of tree and fruit crops in Chile, to five compounds previously identified from the pheromone glands of females. Previously, attraction of m a l es t o th e m aj or co m p o n en t , (7 Z , 10 Z)-7 ,1 0hexadecadienal, was clearly demonstrated while the role of the minor components was uncertain due to the use of an experimental design that left large portions of the design space unexplored. We used mixture designs to study the potential contributions to trap catch of the four minor pheromone components produced by C. valdiviana. After systematically exploring the design space described by the five pheromone components, we concluded that the major pheromone component alone is responsible for attraction of male moths in this species. The need for appropriate experimental designs to address the problem of assessing responses to mixtures of semiochemicals in chemical ecology is described. We present an analysis of mixture designs and response surface modeling and an explanation of why this approach is superior to commonly used, but statistically inappropriate, designs.

Journal of Chemical Ecology, 2020

Leucoptera sinuella is a leaf-miner moth present in several regions in the world, which has been ... more Leucoptera sinuella is a leaf-miner moth present in several regions in the world, which has been recently introduced into Chile. The larvae feed exclusively on the leaves of poplar and willow trees, and the damage caused by the feeding behavior poses a threat to the wood-producing industry. Besides, L. sinuella larvae invade nearby orchards for pupation, causing rejections in Chilean fresh fruit for export. Here we report the identification of the female-produced sex pheromone of L. sinuella as a first step towards the development of pheromone-based methods for pest management of this species. First, we analyzed hexane extracts of the abdominal glands of virgin females by gas chromatography coupled with mass spectrometry and identified the major compound in these extracts to be 3,7-dimethylpentadecane, while minor compounds in the extracts proved to be 3,7dimethyltetradecane and 7-methylpentadecane. Structure assignments were carried out by comparison of retention times and mass spectra of the natural products with those of authentic reference samples. Second, we conducted field tests, which showed that traps baited with synthetic 3,7-dimethylpentadecane were significantly attractive to males in a dose-dependent response. Our results also showed that a mixture of 3,7-dimethylpentadecane, 3,7-dimethyltetradecane, and 7-methylpentadecane in proportions similar to those found in gland extracts was the most attractive lure.

Journal of the Chilean Chemical Society, 2018

The main pheromone component of Chilecomadia valdiviana has recently been reported to be (7Z,10Z)... more The main pheromone component of Chilecomadia valdiviana has recently been reported to be (7Z,10Z)-7,10-hexadecadienal. The synthesis of a structural analog, (5Z,8Z)-5,8-tetradecadienyl formate is reported. The pheromone analog was not attractive to male C. valdiviana in the field, nor did it antagonize attraction of males to the pheromone compound.

PLOS ONE, 2019

The main pheromone compound of Chilecomadia valdiviana (Lepidoptera: Cossidae) has been recently ... more The main pheromone compound of Chilecomadia valdiviana (Lepidoptera: Cossidae) has been recently identified as (7Z,10Z)-7,10-hexadecadienal. The biosynthesis of this pheromone compound showing attributes of both Type I and Type II lepidopteran pheromones was studied by the topical application of isotope-labeled fatty acids to the pheromone gland and subsequent analysis of the gland contents (pheromone compounds and fatty acyl compounds) by gas chromatography-mass spectrometry. The deuterium label of D 11-linoleic acid was incorporated into the pheromone compound and its putative acyl precursor (7Z,10Z)-7,10-hexadecadienoate, demonstrating that the pheromone compound is biosynthesized from linoleic acid by chain-shortening and further functional group transformation. Furthermore, the deuterium label of D 3-stearic acid was also incorporated into the pheromone compound, which indicates that the pheromone can be synthesized de novo by C. valdiviana, as is the case for Type I lepidopteran pheromone compounds.

Journal of Chemical Ecology, 2016

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larv... more Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larval stages feed on the wood of economically important fruit tree species such as apple, pear, olive, cherry, and avocado, and also on eucalyptus. This causes weakening and, in case of severe infestation, death of the tree. We report identification of the sex pheromone produced by females of this species. Hexane extracts of the abdominal glands of virgin females were analyzed by gas chromatography (GC) with electroantennographic detection, GC coupled with mass spectrometry, and GC coupled to infrared spectroscopy. The major pheromone component was identified as (7Z,10Z)-7,10-hexadecadienal (Z7,Z10-16:Ald), and minor components present in the extracts were (Z)-7-hexadecenal and (Z)-9-hexadecenal, hexadecanal, and (9Z,12Z)-9,12-octadecadienal. Structural assignments were carried out by comparison of analytical data of the natural products and their dimethyl disulfide adducts with those of authentic reference samples. In field tests, traps baited with Z7,Z10-16:Ald captured significantly more males than control traps.

Insects, 2021

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is a native xylophagous pest in apple ... more Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is a native xylophagous pest in apple orchards in Chile. A series of experiments evaluated the efficacy of trap type, sex pheromone (Z7,Z10-16:Ald) dose, and trap location in the apple tree canopy on trap catch of male adults. Bucket traps (6 L), with and without roof and cross vane spacers, together with bucket traps (20 L) without roof and spacers, showed higher catches among the four types of traps evaluated. In a second experiment, the UNI-trap and Delta trap showed higher catches than Multipher, wing, and bucket traps (6 L). Male catches were not affected by height when tested at 0, 1.5, and 3 m in the canopy. A 300 µg dose of Z7,Z10-16:Ald showed higher catch than the control treatment. This dose allowed monitoring of male flight of C. valdiviana for at least five weeks in apple orchards in Chile. Based on relative trap costs, we propose the use of 6 L bucket traps for male mass trapping, while Delta traps can be used ...

Molecules, 2016

An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dih... more An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dihydroxy-6-oxo-5α-cholan-24-oate (11), methyl 3α-hydroxy-6-oxo-7-oxa-5α-cholan-24-oate (15) and methyl 3α-hydroxy-6-oxa-7-oxo-5α-cholan-24-oate (16), from hyodeoxycholic acid (4) maintaining the native side chain is described. In the alternative procedure, the di-oxidized product 6, obtained in the oxidation of methyl hyodeoxycholate 5, was converted almost quantitatively into the target monoketone 7 by stereoselective reduction with NaBH 4 , increasing the overall yield of this synthetic route to 96.8%. The complete 1 Hand 13 C-NMR assignments for all compounds synthesized in this work have been made by 1D and 2D heteronuclear correlation gs-HSQC and gs-HMBC techniques. Thus, it was possible to update the spectroscopic information of 1 H-NMR and to accomplish a complete assignment of all 13 C-NMR signals for analogues 5-16, which were previously reported only in partial form.

<p>Mass spectra of (A) natural (7<i>Z</i>,10<i>Z</i>)-7,10-hexadeca... more <p>Mass spectra of (A) natural (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal, (B) D₁₁-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal from glands treated with D₁₁-linoleic acid, (C) D₃-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal from glands treated with D₃-stearic acid.</p

<p>Gas chromatograms of hexane extracts of (A) a pheromone gland treated with DMSO only and... more <p>Gas chromatograms of hexane extracts of (A) a pheromone gland treated with DMSO only and (B) a pheromone gland treated with a solution of D₁₁-linoleic acid in DMSO. Z7,Z10-16:Ald = (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal.</p

<p>Methyl esters of fatty acids identified in a methylated chloroform extract of the pherom... more <p>Methyl esters of fatty acids identified in a methylated chloroform extract of the pheromone gland of <i>Chilecomadia valdiviana</i>.</p

<p>Mass spectra of (A) unlabeled methyl (7<i>Z</i>,10<i>Z</i>)-7,10... more <p>Mass spectra of (A) unlabeled methyl (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienoate from methylated pheromone gland extracts, (B) methyl D₁₁-(7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienoate from pheromone glands treated with D₁₁-linoleic acid.</p

<p>Titers of unlabeled and labeled Z7,Z10-16:Ald in pheromone glands of <i>Chilecomad... more <p>Titers of unlabeled and labeled Z7,Z10-16:Ald in pheromone glands of <i>Chilecomadia valdiviana</i> females, which were treated with isotope-labeled fatty acids.</p

<p>(A) Total ion chromatogram (TIC) of a hexane extract of a pheromone gland treated with D... more <p>(A) Total ion chromatogram (TIC) of a hexane extract of a pheromone gland treated with D₃-stearic acid. Z7,Z10-16:Ald = (7<i>Z</i>,10<i>Z</i>)-7,10-hexadecadienal, Z7-16:Ald = (<i>Z</i>)-7-hexadecenal, Z9-16:Ald = (<i>Z</i>)-9-hexadecenal. (B) Mass chromatograms show the elution of the isotope-labeled pheromone compound (<i>m/z</i> 239, 196, and 182) slightly earlier than the non-labeled compound (<i>m/z</i> 236, 193, and 179).</p

<p>The linoleic acid may be of dietary origin or may be synthesized from stearic acid (dash... more <p>The linoleic acid may be of dietary origin or may be synthesized from stearic acid (dashed arrow).</p

Journal of Chemical Ecology, 2017

Field experiments were carried out to study responses of male moths of the carpenterworm, Chileco... more Field experiments were carried out to study responses of male moths of the carpenterworm, Chilecomadia valdiviana (Lepidoptera: Cossidae), a pest of tree and fruit crops in Chile, to five compounds previously identified from the pheromone glands of females. Previously, attraction of m a l es t o th e m aj or co m p o n en t , (7 Z , 10 Z)-7 ,1 0hexadecadienal, was clearly demonstrated while the role of the minor components was uncertain due to the use of an experimental design that left large portions of the design space unexplored. We used mixture designs to study the potential contributions to trap catch of the four minor pheromone components produced by C. valdiviana. After systematically exploring the design space described by the five pheromone components, we concluded that the major pheromone component alone is responsible for attraction of male moths in this species. The need for appropriate experimental designs to address the problem of assessing responses to mixtures of semiochemicals in chemical ecology is described. We present an analysis of mixture designs and response surface modeling and an explanation of why this approach is superior to commonly used, but statistically inappropriate, designs.

Journal of Chemical Ecology, 2020

Leucoptera sinuella is a leaf-miner moth present in several regions in the world, which has been ... more Leucoptera sinuella is a leaf-miner moth present in several regions in the world, which has been recently introduced into Chile. The larvae feed exclusively on the leaves of poplar and willow trees, and the damage caused by the feeding behavior poses a threat to the wood-producing industry. Besides, L. sinuella larvae invade nearby orchards for pupation, causing rejections in Chilean fresh fruit for export. Here we report the identification of the female-produced sex pheromone of L. sinuella as a first step towards the development of pheromone-based methods for pest management of this species. First, we analyzed hexane extracts of the abdominal glands of virgin females by gas chromatography coupled with mass spectrometry and identified the major compound in these extracts to be 3,7-dimethylpentadecane, while minor compounds in the extracts proved to be 3,7dimethyltetradecane and 7-methylpentadecane. Structure assignments were carried out by comparison of retention times and mass spectra of the natural products with those of authentic reference samples. Second, we conducted field tests, which showed that traps baited with synthetic 3,7-dimethylpentadecane were significantly attractive to males in a dose-dependent response. Our results also showed that a mixture of 3,7-dimethylpentadecane, 3,7-dimethyltetradecane, and 7-methylpentadecane in proportions similar to those found in gland extracts was the most attractive lure.

Journal of the Chilean Chemical Society, 2018

The main pheromone component of Chilecomadia valdiviana has recently been reported to be (7Z,10Z)... more The main pheromone component of Chilecomadia valdiviana has recently been reported to be (7Z,10Z)-7,10-hexadecadienal. The synthesis of a structural analog, (5Z,8Z)-5,8-tetradecadienyl formate is reported. The pheromone analog was not attractive to male C. valdiviana in the field, nor did it antagonize attraction of males to the pheromone compound.

PLOS ONE, 2019

The main pheromone compound of Chilecomadia valdiviana (Lepidoptera: Cossidae) has been recently ... more The main pheromone compound of Chilecomadia valdiviana (Lepidoptera: Cossidae) has been recently identified as (7Z,10Z)-7,10-hexadecadienal. The biosynthesis of this pheromone compound showing attributes of both Type I and Type II lepidopteran pheromones was studied by the topical application of isotope-labeled fatty acids to the pheromone gland and subsequent analysis of the gland contents (pheromone compounds and fatty acyl compounds) by gas chromatography-mass spectrometry. The deuterium label of D 11-linoleic acid was incorporated into the pheromone compound and its putative acyl precursor (7Z,10Z)-7,10-hexadecadienoate, demonstrating that the pheromone compound is biosynthesized from linoleic acid by chain-shortening and further functional group transformation. Furthermore, the deuterium label of D 3-stearic acid was also incorporated into the pheromone compound, which indicates that the pheromone can be synthesized de novo by C. valdiviana, as is the case for Type I lepidopteran pheromone compounds.

Journal of Chemical Ecology, 2016

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larv... more Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larval stages feed on the wood of economically important fruit tree species such as apple, pear, olive, cherry, and avocado, and also on eucalyptus. This causes weakening and, in case of severe infestation, death of the tree. We report identification of the sex pheromone produced by females of this species. Hexane extracts of the abdominal glands of virgin females were analyzed by gas chromatography (GC) with electroantennographic detection, GC coupled with mass spectrometry, and GC coupled to infrared spectroscopy. The major pheromone component was identified as (7Z,10Z)-7,10-hexadecadienal (Z7,Z10-16:Ald), and minor components present in the extracts were (Z)-7-hexadecenal and (Z)-9-hexadecenal, hexadecanal, and (9Z,12Z)-9,12-octadecadienal. Structural assignments were carried out by comparison of analytical data of the natural products and their dimethyl disulfide adducts with those of authentic reference samples. In field tests, traps baited with Z7,Z10-16:Ald captured significantly more males than control traps.

Insects, 2021

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is a native xylophagous pest in apple ... more Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is a native xylophagous pest in apple orchards in Chile. A series of experiments evaluated the efficacy of trap type, sex pheromone (Z7,Z10-16:Ald) dose, and trap location in the apple tree canopy on trap catch of male adults. Bucket traps (6 L), with and without roof and cross vane spacers, together with bucket traps (20 L) without roof and spacers, showed higher catches among the four types of traps evaluated. In a second experiment, the UNI-trap and Delta trap showed higher catches than Multipher, wing, and bucket traps (6 L). Male catches were not affected by height when tested at 0, 1.5, and 3 m in the canopy. A 300 µg dose of Z7,Z10-16:Ald showed higher catch than the control treatment. This dose allowed monitoring of male flight of C. valdiviana for at least five weeks in apple orchards in Chile. Based on relative trap costs, we propose the use of 6 L bucket traps for male mass trapping, while Delta traps can be used ...

Molecules, 2016

An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dih... more An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dihydroxy-6-oxo-5α-cholan-24-oate (11), methyl 3α-hydroxy-6-oxo-7-oxa-5α-cholan-24-oate (15) and methyl 3α-hydroxy-6-oxa-7-oxo-5α-cholan-24-oate (16), from hyodeoxycholic acid (4) maintaining the native side chain is described. In the alternative procedure, the di-oxidized product 6, obtained in the oxidation of methyl hyodeoxycholate 5, was converted almost quantitatively into the target monoketone 7 by stereoselective reduction with NaBH 4 , increasing the overall yield of this synthetic route to 96.8%. The complete 1 Hand 13 C-NMR assignments for all compounds synthesized in this work have been made by 1D and 2D heteronuclear correlation gs-HSQC and gs-HMBC techniques. Thus, it was possible to update the spectroscopic information of 1 H-NMR and to accomplish a complete assignment of all 13 C-NMR signals for analogues 5-16, which were previously reported only in partial form.