scholarly journals Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

2012 ◽  
Vol 8 ◽  
pp. 1246-1255 ◽  
Author(s):  
Nicole Zimmermann ◽  
Robert Hilgraf ◽  
Lutz Lehmann ◽  
Daniel Ibarra ◽  
Wittko Francke
Keyword(s):  
Mass Spectrometry ◽  
Stereoselective Synthesis ◽  
Minor Component ◽  
Parasitoid Wasp ◽  
The Other ◽  
Enantiomerically Pure ◽  
Enantioselective Gas Chromatography ◽  
A Minor ◽  
Stereogenic Center ◽  
Reference Samples

Starting from the enantiomers of limonene, all eight stereoisomers of trans-fused dihydronepetalactones were synthesized. Key compounds were pure stereoisomers of 1-acetoxymethyl-2-methyl-5-(2-hydroxy-1-methylethyl)-1-cyclopentene. The stereogenic center of limonene was retained at position 4a of the target compounds and used to stereoselectively control the introduction of the other chiral centers during the synthesis. Basically, this approach could also be used for the synthesis of enantiomerically pure trans-fused iridomyrmecins. Using synthetic reference samples, the combination of enantioselective gas chromatography and mass spectrometry revealed that volatiles released by the endohyperparasitoid wasp Alloxysta victrix contain the enantiomerically pure trans-fused (4R,4aR,7R,7aS)-dihydronepetalactone as a minor component, showing an unusual (R)-configured stereogenic center at position 7.

scholarly journals Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part II: Iridomyrmecins

2012 ◽  
Vol 8 ◽  
pp. 1256-1264 ◽  
Author(s):  
Robert Hilgraf ◽  
Nicole Zimmermann ◽  
Lutz Lehmann ◽  
Armin Tröger ◽  
Wittko Francke
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Stereoselective Synthesis ◽  
Minor Component ◽  
Parasitoid Wasp ◽  
Enantioselective Gas Chromatography ◽  
A Minor

Following our earlier approach to the synthesis of dihydronepetalactones, all eight stereoisomers of trans-fused iridomyrmecins were synthesized starting from the enantiomers of limonene. Combined gas chromatography and mass spectrometry including enantioselective gas chromatography revealed that volatiles released by the endohyperparasitoid wasp Alloxysta victrix contain (4S,4aR,7S,7aR)-iridomyrmecin of 95–97% ee and stereochemically pure (4S,4aS,7R,7aS)-iridomyrmecin as a minor component.

scholarly journals Murine B-cell subpopulations responsive to T-dependent and T-independent antigens.

1976 ◽  
Vol 144 (2) ◽  
pp. 382-397 ◽  
Author(s):  
G K Lewis ◽  
R Ranken ◽  
D E Nitecki ◽  
J W Goodman
Keyword(s):  
B Cells ◽  
B Cell ◽  
Minor Component ◽  
Memory Cell ◽  
Keyhole Limpet Hemocyanin ◽  
The Other ◽  
Other Hand ◽  
Cell Mitogen ◽  
A Minor

Strain A/J mice made secondary indirect plaque-forming cell (PFC) responses to azobenzenearsonate (ABA) conjugates of giant keyhole limpet hemocyanin (KLH), a thymic-dependent antigen, but not to conjugates of Ficoll, a T-independent antigen. ABA-Ficoll was also unable to elicit a response in animals primed with ABA-KLH, which have an expanded anti-ABA memory cell pool. On the other hand, ABA-Ficoll rendered mice unresponsive to ABA-KLH when administered before priming or boosting with the T-dependent immunogen. Hence, the T-independent antigen was able to tolerize but unable to trigger B-memory cells responsive to the T-dependent antigen. A/J mice immunized with dinitrophenyl conjugates of Ficoll or bovine IgG (BGG) made vigorous IgM and IgG PFC responses. PFC responses to ABA-KLH and 2,4-dinitrophenyl (DNP)-BGG were abrogated by depleting mice of C3 with cobra venom factor, whereas the IgM and IgG PFC responses to DNP-Ficoll were unaffected. B lymphocytes were fractionated on the basis of receptors for C3 and the subpopulations were assayed for in vitro PFC responses to DNP-Ficoll. Very little response was obtained from complement receptor lymphocyte [CRL(+)] B cells, whereas CRL(-) cells were more responsive than unfractionated B cells. Both populations responded to a polyclonal B-cell mitogen (lipopolysaccharide). On the other hand, the in vitro PFC response to a T-dependent antigen (sheep erythrocytes) correlated with the presence of CRL(+) B cells in the cultures. However, a minor component of this response, sensitive to anti-Thy-1 serum, was made by CRL(-) B cells, indicating the existence of subpopulations of T-dependent B cells with different signalling requirements. The results suggest that most B cells responsive to T-dependent antigens possess receptors for C3 and that C3 plays an obligatory role in the response of these cells. A distinct subpopulation of B cells which lack C3 receptors respond to T-independent antigens. The precursors of PFC for the ABA epitope reside largely or exclusively in the CRL(+) compartment in A/J mice, whereas precursors for the DNP determinant are found in both compartments.

Stereoselective syntheses of isomers of 3,7-dimethylnonadecane, a sex pheromone of the alfalfa blotch leafminer (Agromyza frontella (Rondani))

1991 ◽  
Vol 69 (7) ◽  
pp. 1100-1106 ◽  
Author(s):  
David Miller ◽  
François Bilodeau ◽  
Robert H. Burnell
Keyword(s):  
Optical Properties ◽  
Sex Pheromone ◽  
Key Words ◽  
Stereoselective Synthesis ◽  
Starting Material ◽  
The Other ◽  
Stereogenic Center ◽  
Stereoselective Syntheses ◽  
Alfalfa Blotch Leafminer ◽  
Agromyza Frontella

Two related stereoselective syntheses of 3,7-dimethylnonadecane, a sex pheromone of the alfalfa leafminer, are described to show that pulegone can serve as a useful starting material for the preparation of chiral aliphatic isoprenoid compounds. The schemes are designed to place the stereogenic center of pulegone at C.3 in one synthesis and at C.7 in the other so that the optical properties of the products can be compared with one another and with the values calculated using Brewster's rules. Key words: chiral hydrocarbons, stereoselective synthesis, pheromone, Agromyza frontella.

Interferences appearing in fluorometrically measured liquid-chromatographic profiles of creatine kinase isoenzymes in serum.

1980 ◽  
Vol 26 (6) ◽  
pp. 707-711 ◽  
Author(s):  
T D Schlabach ◽  
J A Fulton ◽  
P B Mockridge ◽  
E C Toren
Keyword(s):  
Creatine Kinase ◽  
High Performance ◽  
Minor Component ◽  
The Other ◽  
Present Evidence ◽  
Human Sera ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Measured Liquid ◽  
Chromatographic Profiles

Abstract We observed nonenzymic peaks when serum isoenzymes of lactate dehydrogenase (EC 1.1.1.27; LD) and creatine kinase (EC 2.7.3.2.; CK) were separated by “high-performance” liquid chromatography and detected by continuously monitoring the column effluent for enzyme activity. Such background peaks were particularly apparent in CK isoenzyme profiles obtained from human sera. We observed two nonenzymic peaks with fluorescence detection, one in the CK-MB region, the other in the CK-BB region. Serum albumin was a major component in the artifactual CK-MB peak, with lipoprotein as a minor component. We present evidence that the material responsible for the other peak fluoresced quite strongly and is mostly pre-albumin.

scholarly journals Mass Spectrometry–Based Detection of Hemoglobin E Mutation by Allele-Specific Base Extension Reaction

2007 ◽  
Vol 53 (12) ◽  
pp. 2205-2209 ◽  
Author(s):  
Jason CH Tsang ◽  
Pimlak Charoenkwan ◽  
Katherine CK Chow ◽  
Yongjie Jin ◽  
Chanane Wanapirak ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Prenatal Diagnosis ◽  
Annealing Temperature ◽  
The Other ◽  
Detection Sensitivity ◽  
Hemoglobin E ◽  
Noninvasive Prenatal Diagnosis ◽  
Base Extension ◽  
Allele Specific ◽  
A Minor

Abstract Background: The specific detection of a minor population of mutant DNA molecules requires methods of high specificity and sensitivity. While the single-allele base extension reaction (SABER) was shown to be useful for the detection of certain beta-thalassemia mutations, we encountered problems with false positivity during development of SABER for the noninvasive prenatal diagnosis of the hemoglobin E (HbE) disease. Systematic optimization resulted in an alternative protocol, the allele-specific base extension reaction (ASBER). Methods: An artificial model was established by mixing genomic DNA of HbE carriers and normal individuals. Effects of terminator concentration and annealing temperature on the nonspecificity of SABER were then studied. The use of a single relevant terminator and the other 3 types of dideoxynucleotide as competing terminators were also compared in the development of the ASBER protocol. Thirteen cases of HbE-susceptible pregnancies were tested to compare the SABER and the ASBER protocols. Results: Decreasing the single relevant terminator concentration and increasing the annealing temperature in SABER were found to improve specificity. The use of the other 3 types of dideoxynucleotide as competing terminators was shown to offer better detection sensitivity than a single terminator in ASBER. Genotyping results were all correctly determined by ASBER, except one false-negative detection (sensitivity: 80%, specificity: 100%). Conclusions: An alternative mass spectrometry–based protocol for noninvasive prenatal diagnosis, ASBER, has been successfully developed to allow the detection of a minor DNA population with a point mutation.

scholarly journals Two subsets of human T lymphocytes expressing gamma/delta antigen receptor are identifiable by monoclonal antibodies directed to two distinct molecular forms of the receptor.

1988 ◽  
Vol 168 (2) ◽  
pp. 491-505 ◽  
Author(s):  
C Bottino ◽  
G Tambussi ◽  
S Ferrini ◽  
E Ciccone ◽  
P Varese ◽  
...  
Keyword(s):  
Target Cell ◽  
Peripheral Blood ◽  
Minor Component ◽  
The Other ◽  
Molecular Forms ◽  
Gamma Delta ◽  
Gamma Receptor ◽  
Other Hand ◽  
Reducing Conditions ◽  
A Minor

Two mAbs directed to the TCR-gamma/delta were analyzed for their pattern of reactivity with CD3+WT31- cell populations or clones. In normal individuals, the BB3 mAb reacted with approximately 2/3 of peripheral blood CD3+WT31- lymphocytes, whereas delta-TCS-1 stained approximately 1/3 of such cells. In addition, the sum of the percentages of BB3+ and delta-TCS-1+ cells approximated the percentages of peripheral blood CD3+WT31- lymphocytes in seven normal donors tested. Also, in peripheral blood-derived polyclonal CD3+WT31- populations, cultured in IL-2, cells reacting with one or another mAb accounted for the whole cell population. On the other hand, only delta-TCS-1-reactive cells, but not BB3+ cells, could be detected in unfractionated as well as in CD4-8-thymocyte populations. Analysis of peripheral blood-derived CD3+WT31- clones showed that 70% of 72 clones analyzed reacted with BB3 mAb, but not with delta-TCS-1 mAb. On the other hand, delta-TCS-1 mAb stained the remaining BB3- clones. Five clones expressing medium-low amounts of CD8 antigen were BB3- delta-TCS-1+. Both types of clones lysed the Fc gamma receptor-bearing P815 target cell in the presence of anti-CD3 mAb (but not of mAb directed against HLA-DR, CD7 molecules, or TCR-alpha/beta). In this cytolytic assay, BB3 mAb induced target cell lysis only by BB3+ clones, whereas delta-TCS-1 mAb was effective only with delta-TCS-1+ clones. The CD3-associated surface molecules expressed by BB3+ or delta-TCS-1+ clones were analyzed after cell surface iodination and immunoprecipitation with the corresponding anti-TCR mAb or with anti-CD3 mAb (in digitonin-containing buffer). In SDS-PAGE, molecules immunoprecipitated from 13 BB3+ clones displayed, under nonreducing conditions, a molecular weight of 80 kD (in some cases, a minor 38-kD band could be detected). Under reducing conditions, two major components of 44 and 41 kD (and a minor component of 38 kD) were detected. On the other hand, TCR molecules immunoprecipitated from 11 different delta-TCS-1+ clones appeared as a diffuse band of 41-44 kD, both under reducing and nonreducing conditions (under non-reducing condition, an additional 38-kD band was present). Therefore, BB3+ cells express a disulphide-linked form of TCR-gamma/delta whereas delta-TCS-1+ cells express a non-disulphide-linked form.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Mate attraction, chemical defense, and competition avoidance in the parasitoid wasp Leptopilina pacifica

Chemoecology ◽  
2020 ◽  
Author(s):  
Lea C. Böttinger ◽  
Frederic Hüftlein ◽  
Johannes Stökl
Keyword(s):  
Sex Pheromone ◽  
Defensive Secretion ◽  
Minor Component ◽  
Parasitoid Wasp ◽  
Primary Component ◽  
Sister Species ◽  
Wasp Species ◽  
Competition Avoidance ◽  
Species Specific ◽  
A Minor

AbstractA major hypothesis for the evolution of chemical signals is that pheromones arise from non-communicative precursor compounds. However, data supporting this hypothesis are rare, primarily because the original functions of the antecedent compounds often have been lost. A notable exception, however, is the parasitoid wasp species Leptopilina heterotoma, whose compound (−)-iridomyrmecin is used as a defensive secretion, a cue for females to avoid competition with con- and hetero-specific females, and as the primary component of the females’ sex pheromone. To better understand the evolution of sex pheromones from defensive compounds, we examined the chemical ecology of L. pacifica, the sister species of L. heterotoma. Here, we show that L. pacifica also produces a defensive secretion containing a species-specific mixture of mostly iridoid compounds. However, the composition of the secretion is more complex than in L. heterotoma, and iridomyrmecin is only a minor component. Moreover, in contrast to L. heterotoma, conspecific female competitors were not avoided by female subjects, and a role of the iridoids in the female sex pheromone of L. pacifica can be excluded, as only the females’ cuticular hydrocarbons (CHCs) resulted in the elicitation of courtship by males. Although closely related, the two sister species show substantial differences in the use of the defensive secretion for communicative purposes. Variation in pheromone usage in this genus still presents a conundrum, highlighting the need for additional studies to understand the selective forces shaping the evolution of pheromone composition.

The isolation and identification of makisterone A from the yew, Taxus cuspidata

1977 ◽  
Vol 55 (7) ◽  
pp. 1129-1134 ◽  
Author(s):  
Brenton Garth Burns ◽  
Michael Wilson Gilgan
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Trimethylsilyl Ether ◽  
Minor Component ◽  
Reversed Phase ◽  
Taxus Cuspidata ◽  
Isolation And Identification ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Magnetic Resonance Spectrometry ◽  
A Minor

The ecdysteroids were extracted from yew, Taxus cuspidata, needles and twigs and recovered from the aqueous extract by reversed phase adsorption. Purification of the ecdysteroids was achieved by a single solvent partition and a dry column chromatogram followed by fractionation on an adsorptive Porasil A (60) column. Makisterone A was a minor component identified by melting point, liquid chromatography, gas chromatography of the trimethylsilyl ether, mass spectrometry, and nuclear magnetic resonance spectrometry. A second minor component was isolated but not identified.

scholarly journals Halogens in Eclogite Facies Minerals from the Western Gneiss Region, Norway

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 760
Author(s):  
Lewis Hughes ◽  
Simon Cuthbert ◽  
Alex Quas-Cohen ◽  
Lorraine Ruzié-Hamilton ◽  
Alison Pawley ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fluid Inclusions ◽  
Secondary Ion Mass Spectrometry ◽  
Noble Gas ◽  
Minor Component ◽  
Fluid Composition ◽  
Alternative Source ◽  
Western Gneiss Region ◽  
A Minor ◽  
Multi Phase

Ultra-high-pressure (UHP) eclogites and ultramafites and associated fluid inclusions from the Western Gneiss Region, Norwegian Caledonides, have been analysed for F, Cl, Br and I using electron-probe micro-analysis, time-of-flight secondary ion mass spectrometry and neutron-irradiated noble gas mass spectrometry. Textures of multi-phase and fluid inclusions in the cores of silicate grains indicate formation during growth of the host crystal at UHP. Halogens are predominantly hosted by fluid inclusions with a minor component from mineral inclusions such as biotite, phengite, amphibole and apatite. The reconstructed fluid composition contains between 11.3 and 12.1 wt% Cl, 870 and 8900 ppm Br and 6 and 169 ppm I. F/Cl ratios indicate efficient fractionation of F from Cl by hydrous mineral crystallisation. Heavy halogen ratios are higher than modern seawater by up to two orders of magnitude for Br/Cl and up to three orders of magnitude for I/Cl. No correlation exists between Cl and Br or I, while Br and I show good correlation, suggesting that Cl behaved differently to Br and I during subduction. Evolution to higher Br/Cl ratios is similar to trends defined by eclogitic hydration reactions and seawater evaporation, indicating preferential removal of Cl from the fluid during UHP metamorphism. This study, by analogy, offers a field model for an alternative source (continental crust) and mechanism (metasomatism by partial melts or supercritical fluids) by which halogens may be transferred to and stored in the sub-continental lithospheric mantle during transient subduction of a continental margin.

Interferences appearing in fluorometrically measured liquid-chromatographic profiles of creatine kinase isoenzymes in serum.

1980 ◽  
Vol 26 (6) ◽  
pp. 707-711
Author(s):  
T D Schlabach ◽  
J A Fulton ◽  
P B Mockridge ◽  
E C Toren
Keyword(s):  
Creatine Kinase ◽  
High Performance ◽  
Minor Component ◽  
The Other ◽  
Present Evidence ◽  
Human Sera ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Measured Liquid ◽  
Chromatographic Profiles

Abstract We observed nonenzymic peaks when serum isoenzymes of lactate dehydrogenase (EC 1.1.1.27; LD) and creatine kinase (EC 2.7.3.2.; CK) were separated by “high-performance” liquid chromatography and detected by continuously monitoring the column effluent for enzyme activity. Such background peaks were particularly apparent in CK isoenzyme profiles obtained from human sera. We observed two nonenzymic peaks with fluorescence detection, one in the CK-MB region, the other in the CK-BB region. Serum albumin was a major component in the artifactual CK-MB peak, with lipoprotein as a minor component. We present evidence that the material responsible for the other peak fluoresced quite strongly and is mostly pre-albumin.

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