Cembrene A and a congeneric ketone isolated from the paracloacal glands of the Chinese alligator (Alligator sinensis).

A diterpene hydrocarbon and diterpene ketone isolated from the paracloacal gland secretions of the Chinese alligator (alligator sinensis) were examined by GC-MS and 1H-NMR, 13C-NMR, and IR spectroscopy, and identified as 4,8,12-trimethyl-1-(1-methylethenyl)-3,7,11-cyclotetradecatrien e (cembrene A, 1) and its congeneric ketone, 4,8,12-trimethyl-1-(1-methylethenyl)-3,7-cyclotetradecadien- 10-one (2), respectively. This is the first report of cembrene A from a vertebrate; the ketone has not been described previously.

Lipids from the paracloacal glands of the chinese alligator (Alligator sinensis).

Lipids from the paracloacal glands of adult Chinese alligators (Alligator sinensis) were analyzed by gas chromatography/mass spectrometry. Acetates, aliphatic alcohols, free fatty acids and waxes consisting primarily of hexadecanoates were indicated in the secretions of males and females. Cholesterol, a diterpene hydrocarbon, and a diterpene ketone were detected in secretions of males but not in those of females. Lipids identified in the paracloacal secretions ofA. sinensis are compared with those reported from the American alligator and other crocodilians.

Mandibular gland secretions of the male beewolvesPhilanthus crabroniformis, P. barbatus, andP. pulcher (Hymenoptera: Sphecidae).

The composition of the territorial marking pheromones from mandibular glands of males of the beewolvesPhilanthus crabroniformis, P. barbatus, andP. pulcher have been determined. The structures of the components were elucidated by gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy. The major compound ofP. crabroniformis is isopropyl tetradecanoate, with somewhat lesser amounts of 2-tridecanone, 3-methyl-3-butenyl tetradecanoate, and 92∶8 (Z)∶(E)-11-eicosen-1-ol. The major compounds ofP. barbatus are ethyl tetradecanoate and hexadecanal, which are present in approximately a 60∶40 ratio. These two compounds comprise over 95% of the neutral lipids. Also present in lesser amounts are ethyl dodecanoate, tetradecanal, hexadecan-1-ol, a Δ (x) -octadecen-1-ol, and octadecan-1-ol. The major compounds ofP. pulcher are ethyl (Z)-7-hexadecenoate and geranylgeraniol acetate, which comprise nearly 90% of the neutral lipid fraction, with smaller amounts of tetradecanal, pentadecanal, and ethyl hexadecanoate; trace amounts of Δ (x) hexadecenal, hexadecanal, and octadecanal are also present.

Major antitermitic components of the heartwood of southern catalpa.

The heartwood of southern catalpa,Catalpa bignonioides Walt., is resistant to attack by the eastern subterranean termiteReticulitermes flavipes (Kollar), but extraction with a ternary solvent mixture of acetone-hexanewater (54∶44∶2) by volume removed the antitermitic characteristics from the heartwood. Four compounds comprised approximately 98% of the antitermitic fraction of the extract: the sesquiterpene alcohol, catalponol (67%); its epimer, epicatalponol (5%); a structurally related ketone, catalponone (1%); and the phthalide, catalpalactone (25%). Pure compounds were isolated by semipreparative scale reversed-phase HPLC and identified by GC-MS and UV spectroscopy. The structure of catalponol was further confirmed by the formation of derivatives. Bioassays indicated that catalponol had the greatest toxicity in cellulose pad tests, but in tests using vacuum impregnation of these compounds into termite-susceptible wood blocks at levels approximating those found in catalpa heartwood, catalpalactone exhibited the highest antitermitic activity.

Chemistry of male mandibular gland secretions ofPhilanthus triangulum.

Males of the European and African beewolf,Philanthus triangulum, possess a sex specific mandibular gland secretion that is used for marking plant stems in mating territories. The secretion is composed of 90% (Z)-11-eicosen-1-ol plus small amounts of 10-nonadecen-2-one, nonadecenal, octadecanoic and octadecenoic acids, and eicosenal. The chemistry of this secretion differs markedly from the secretions of North AmericanPhilanthus, which consist of a larger number of components that possess different chemical functionalities and are more volatile. We postulate that the chemical differences betweenP. triangulum and its New World relatives reflect phylogenetic differences plus a possible reduced necessity for species isolating mechanisms inP. triangulum.

Chemistry of male mandibular gland secretions ofPhilanthus basilaris cresson andPhilanthus bicinctus (Mickel) (Hymenoptera: Sphecidae).

Detailed chemical characterizations are provided for the species-specific mixtures of marking pheromones utilized by the male beewolvesPhilanthus basilaris andP. bicinctus. Successful analysis of these complex mixtures of 2-ketones, fatty acids, ethyl esters, and aldehydes was facilitated by the treatment of the crude extracts with 1,1-dimethylhydrazine and direct analysis of the resulting hydrazones, methyl esters, and starting ethyl esters by GC-MS.

Mass spectral determination of aldehydes, ketones, and carboxylic acids using 1,1-dimethylhydrazine.

Analyses of nanogram to milligram quantities of aliphatic aldehydes, fatty acids, and unhindered aliphatic ketones such as those typically found in pheromonal blends have been effected by treating these mixtures with 1,1-dimethylhydrazine. The aldehydes and ketones formN,N-dimethylhydrazones, while the fatty acids form methyl esters. Structural elucidation of the reaction products was achieved using EI and CI gas chromatography-mass spectrometry.

Volatiles from mandibular glands of male beewolves (Hymenoptera: Sphecidae,Philanthus) and their possible roles.

Observations of wasp behavior indicate that male beewolves,Philanthus basilaris andP. bicinctus apply a "marking pheromone" to the leaves and stems of plants within their territories. We now provide direct evidence for the presence of volatile chemicals in the paired mandibular glands of the males, provide preliminary identification of these volatiles, and show that all of the volatile chemicals in the mandibular glands are present on freshly marked plant surfaces but are absent from unmarked plants. Pyrazines, which have been reported in other species of aculeate wasps including the EuropeanPhilanthus triangulum, were not found inP. basilaris orP. bicinctus.

Antigen-specific soluble helper activity for murine major histocompatibility complex-encoded molecules. I. Kinetics of factor production after skin transplantation and genetic mapping of the H-2 region specificity.

Antigen-specific soluble helper molecules are produced during major histocompatibility complex-disparate allograft priming. Genetic mapping studies with appropriate recombinant and mutant lines of mice have defined the antigen specificities of the soluble helper molecules described here as being directed against the H-2Dd molecules. The production of antigen-specific helper molecules is a relatively early event after H-2Dd-region allograft priming. A later phase of factor production near the time of graft rejection also contains nonspecific helper factors and IL-2.

Cuticular hydrocarbons ofReticulitermes virginicus (Banks) and their role as potential species- and caste-recognition cues.

The cuticular hydrocarbon components of four castes ofReticulitermes virginicus (Banks) have been identified and quantitated. Components identified includen-alkanes; 2-, 3-, 11-, 13-, and 15-methyl-alkanes; 11,15-dimethylalkanes, (Z)-9-alkenes; (Z,Z)-7,9-dienes; and (E/Z)-6,9-dienes ranging in carbon number from C21 to C40. All caste forms ofR.virginicus contained the same components, but showed caste-specific proportions. Comparison of these hydrocarbons with those of the sympatric termiteR. flavipes (Kollar) suggest that cuticular hydrocarbons might serve as species- and caste-recognition cues. A bioassay was developed to test this species-recognition hypothesis, with the experimental results supporting the hypothesis.

Venom chemistry of ants in the genusMonomorium.

A comparative analysis of the venomous alkaloids produced by ant species in the subgenusMonomorium of the genusMonomorium has been undertaken. All species produce mixtures of unsymmetricaltrans-2,5-dialkylpyrrolidines, but the proportions of the constituents may vary considerably between species. All alkaloids contain both C6 and C9 side chains which are present as C9-saturated. C6-monounsaturated, and both C6-and C9-monounsaturated dialkylpyrrolidines. The structure of 2-(1-hex-5-enyl)-5-(1-non-8-enyl)pyrrolidine, a previously undescribed alkaloid, was proved by unambiguous synthesis after the location of the double bonds was established by the methoxymercuration-demercuration followed by mass spectrometry. The possible chemotaxonomic significance of the mixtures of venomous alkaloids produced by these species ofMonomorium is discussed.

Chemical mimicry as an integrating mechanism: cuticular hydrocarbons of a termitophile and its host.

The staphylinid beetle Trichopsenius frosti Seevers has the same cuticular hydrocarbons as those of its host termite Reticulitermes flavipes (Kollar) and it biosynthesizes them. These cuticular hydrocarbons probably serve as the primary mechanism by which Trichopsenius frosti integrates itself into the termite colony.

Sampling and analysis of pesticides in the environment.

Environmental monitoring is now recognized as essential in areas of pesticide use in order to assess the impact of these pesticides on the environment. During the last two decades, advances in instrumentation in terms of detection limits and specificity, along with the growing expertise of residue chemists, have made reports of pesticide residue levels in the parts per billion range commonplace. Using this technical ability and carefully assessing the significance of the data obtained, pesticides can be used in a more efficacious manner with less possible damage to the environment.