Cephalic Extracts Research Articles

Male meliponine bees (Scaptotrigona aff. depilis) produce alarm pheromones to which workers respond with fight and males with flight.

In highly social hymenopteran societies, males mainly serve reproductive purposes. Semiochemicals enable the different hymenopteran sexes and castes to communicate with each other and to coordinate important functions within colonies. I hereby show that sexual dimorphism in meliponine bees incorporates the alarm and defence communication system. I chemically analysed the mandibular glands of Scaptotrigona aff. depilis using GCMS methods and conducted behavioural experiments in both males and female workers using cephalic and mandibular gland extracts. In addition, behaviour studies with male cephalic extracts were also conducted in Scaptotrigona bipunctata and Partamona cupira. Males and female worker bees showed differences in the content of the mandibular glands, which are responsible for alarm communication in meliponines. Males never attacked but usually fled when confronted with the mandibular gland extract content of other conspecific males or females. Interestingly, however, meliponine males were still able to raise alarm and to induce substantial amounts of aggression at nest entrances, which is different from the much better known and studied honey bees. Potential reasons are briefly discussed.

Stingless Bees: Chemical Differences and Potential Functions in Nannotrigona testaceicornis and Plebeia droryana Males and Workers

Cuticular wax, abdominal and cephalic extracts of foraging workers and males of Nannotrigona testaceicornis and Plebeia droryana, from the "Aretuzina" farm in São Simão, SP, Brazil, were analyzed by GC-MS. The principal constituents were hydrocarbons, terpenes, aldehydes, esters, steroids, alcohols, and fatty acids. Interspecific differences for both cuticular wax and cephalic extracts were found. The composition of cuticular wax and cephalic extracts was similar at the intraspecific level, with minor component differences between males and workers. Abdominal extracts differentiated sexes (male and worker) at the intraspecific and interspecific levels. The main chemical components in abdominal extracts of N. testaceicornis workers and males were geranylgeranyl acetate and (Z)-9-nonacosene, respectively. The principal components of abdominal extracts from P. droryana workers and males were tetradecanal and unsaturated fatty acids (linoleic and linolenic acids), respectively. A secondary alcohol, (S)-2-nonanol, was detected in Plebeia droryana males only, but not in workers. Preliminary field experiments showed that (S)-(+)-2-heptanol and (S)-(+)-2-heptanol/(S)-(+)-2-nonanol (1:1) attracted workers of P. droryana, N. testaceicornis,and Frieseomelitta silvestrii. However, males did not respond suggesting that these compounds do not function as alarm or recruitment pheromones. In addition, racemic mixtures were inactive.

Mandibular gland secretions of meliponine worker bees: further evidence for their role in interspecific and intraspecific defence and aggression and against their role in food source signalling

Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location. We studied Trigona spinipes and Scaptotrigona aff. depilis ('postica'), two sympatric species to which this hypothesis was applied. Using extracts of carefully dissected glands instead of crude cephalic extracts we analysed the substances contained in the mandibular glands of worker bees. Major components of the extracts were 2-heptanol (both species), nonanal (T. spinipes), benzaldehyde and 2-tridecanone (S. aff. depilis). The effect of mandibular gland extracts and of individual components thereof on the behaviour of worker bees near their nest and at highly profitable food sources was consistent. Independent of the amount of mandibular gland extract applied, the bees overwhelmingly reacted with defensive behaviour and were never attracted to feeders scented with mandibular gland extract or any of the synthetic chemicals tested. Both bee species are capable of using mandibular gland secretions for intra- and interspecific communication of defence and aggression and share 2-heptanol as a major pheromone compound. While confirming the role of the mandibular glands in nest defence, our experiments provide strong evidence against their role in food source signalling.

Reporter Expression, Induced by a Growth Hormone Promoter-Driven Cre Recombinase (rGHp-Cre) Transgene, Questions the Developmental Relationship between Somatotropes and Lactotropes in the Adult Mouse Pituitary Gland

This report describes the development and validation of the rGHp-Cre transgenic mouse that allows for selective Cre-mediated recombination of loxP-modified alleles in the GH-producing cells of the anterior pituitary. Initial screening of the rGHp-Cre parental line showed Cre mRNA was specifically expressed in the anterior pituitary gland of adult Cre+/- mice and cephalic extracts of e17 Cre+/- fetuses. Heterozygote rGHp-Cre transgenic mice were crossbred with Z/AP reporter mice to generate Cre+/-,Z/AP+/- offspring. In this model system, the GH promoter-driven, Cre-mediated recombination of the Z/AP reporter leads to human placental alkaline phosphatase (hPLAP) expression that serves to mark cells that currently produce GH, in addition to cells that would have differentiated from GH cells but currently do not express the GH gene. Double immunocytochemistry of adult male and female Cre+/-,Z/AP+/- pituitary cells revealed the majority (approximately 99%) of GH-producing cells of the anterior pituitary also expressed hPLAP, whereas ACTH-, TSH-, and LH-producing cells were negative for hPLAP, confirming previous reports that corticotropes, thyrotropes, and gonadotropes develop independently of the somatotrope lineage. A small subset (approximately 10%) of the prolactin-producing cells was positive for hPLAP, consistent with previous reports showing lactotropes can arise from somatotropes during pituitary development. However, the fact that 90% of prolactin-producing cells were negative for hPLAP suggests that the majority of lactotropes in the adult mouse pituitary gland develop independently of the somatotrope lineage. In addition to developmental studies, the rGHp-Cre transgenic mouse will provide a versatile tool to study the role of a variety of genes in somatotrope function and neoplastic transformation.

Inhibitors of Platelet Aggregation from Diverse Haematophagous and Predaceous Hirudinea from around the World.

IntroductionHaematophages, animals evolved to a blood sucking lifestyle as their exclusive mode of feeding secrete compounds capable of arresting haemostasis in the host. Since the discovery and subsequent characterisation and engineering of hirudin, attention is being focused on the potential anticoagulant and platelet aggregation inhibitors from an array of different species of leech from both the Rhynchobdellid and Arhynchobdellid orders. The purpose of this study was to survey the presence of inhibitors of platelet aggregation in cephalic extracts prepared from phylogenetically diverse proboscis-bearing and jawed blood-sucking leeches compared to those which are predaceous in nature.MethodsCephalic extracts from specimens of each species were prepared by homogenising in tris buffer the anterior one-third region of the bodies containing the salivary glands. In the case of the giant leech, Haementeria ghilianii, paired anterior salivary glands were excised through the oesophagus. The posterior musculature served as control material. Homogenates were double centrifuged and supernatants micro-filtered. Individual extracts or imidazole buffer as control were pre-incubated 1:4 with platelet rich plasma for 5 minutes prior to testing for inhibition of platelet aggregation. Inducers of aggregation were: ADP (5 and 10 μM/ml), Collagen (COL) (4μg/ml), Thrombin (THR) (0.2 U/ml), Ristocetin (RIS) (1.5 mg/ml) and Adrenaline (ADR) (1 μM). Maximal aggregation responses were measured over 10 minutes. All extracts were kept on ice and tested within 1 hour of preparation.ResultsThe species of leeches examined and maximal aggregation responses (%) after 10 minutes are shown in table 1.Maximal Responses (%) to Aggregation Inducers in Haematophagous and Predaceous LeechesSpeciesSourceADPCOLTHRRISADRHaematophagusHaementeria ghilianiiBrazil<10<10<10<10<10Oothuizobdell garouiSouth Africa<10<10<102015Placobdella parasiticaCanada1010<101520Hirudinaria manillensisChina<10<10<10<10<10Macrobdella decoraNorth America<10<10<10<10<10Hirudinaria javanicaIndonesia<10<10<10<10<10Poecilobdella granuloseIndia<10<10<10<10<10Myxobdella AfricanaKenya1520<102025Hirudo medicinalisTurkey<10<10<10<10<10PredaceousHaemopis sanguisugaUK100100100100100Helobdella stagnalisUK909095100100Erpobdella octoculataUK1009595100100Glossiphonia complanataUK100100100100100None of the extracts induced the spontaneous aggregation of platelets suspended in autologous plasma. Posterior musculatures did not inhibit platelet aggregation.ConclusionCephalic extracts from all the haematophagous leeches examined in this study contain inhibitors of platelet aggregation. Our findings suggest that anti-haemostatic properties in Hirudinea appear to have evolved in response to biological adaptations rather than in keeping with phylogenetic affinities. Further work is required to define the precise nature of such mechanisms. These new anti-platelet properties in different species could have further potential therapeutic applications.

Identification of Queen Sex Pheromone Components of the Bumblebee Bombus terrestris

We investigated the origin and chemical composition of the queen sex pheromone of the primitively eusocial bumblebee, Bombus terrestris (Apidae). Physiologically and behaviorally active compounds were identified by coupled gas chromatography electro-antennography (GC-EAD), gas chromatography-mass spectrometry (GC-MS), and laboratory behavioral tests. In the behavioral assays, virgin queens frozen previously at -20 degrees C were highly attractive to males. Dummies impregnated with surface and cephalic extracts obtained from virgin queens that had been frozen at -50 degrees C were more attractive to males than odorless dummies. Male mating behavior was stimulated by components of cephalic secretions that are smeared onto the cuticle surface by the queen. Overall, 21 compounds present in surface and cephalic extracts evoked electroantennographic responses in male antennae. These included saturated and unsaturated fatty acids, ethyl- and methyl esters of the fatty acids, heptacosene, 2-nonanone, and geranyl geraniol. A blend of synthetic versions of these compounds elicited typical male mating behavior. Since solvent-impregnated dummies were approached by the males, but did not release copulatory behavior, visual cues may be important in the initial step of stimulating male mating behavior. Close-range olfactory signals are more important for releasing male mating behavior as well as for species recognition. In further behavioral assays, the attractiveness of a frozen virgin queen decreased as the storage time at -20 degrees C increased from 2 hr to 1 d. Therefore, the chemical composition of the sex pheromone may change during freezing as behaviorally active compounds may decompose.

Pollination by Sexual Mimicry in Mormolyca ringens: A Floral Chemistry that Remarkably Matches the Pheromones of Virgin Queens of Scaptotrigona sp.

The chemical composition of some volatile (2-heptanol) and nonvolatile constituents (a homologous 9-alkene/alkane series) of Mormolyca ringens flowers and Scaptotrigona sp. queen waxes (homologous 9-alkene/alkane series) and cephalic extracts (homologous series of 2-alkanols, including 2-heptanol) involved with the pseudocopulation or sexual mimicry in Orchidaceae pollination is compared. The similarity in chemical composition of flowers and insects is assigned to the chemically induced copulatory activity in Scaptotrigona males.

Anti-Haemostatic Properties of Diverse Haematophagous Hirudinea from around the World Could Have New Therapeutic Potentials.

The purpose of this study was to survey the anti-haemostatic nature of cephalic extracts prepared from phylogenetically diverse rhyncobdellid (proboscis-bearing) and arhynchobdellid (jawed) leeches and to evaluate the significance in the context of their evolutionary development. Cephalic extracts from specimens of each species were prepared by homogenising in tris buffer the anterior one-third region of the bodies containing the salivary glands. In the case of the giant leech Haementeria ghilianii, paired anterior salivary glands were removed by excision through the oesophagus. The posterior musculature served as control material. Homogenates were double-centrifuged and supernatants micro-filtered. Individual extracts (or imidazole buffer as control) were pre-incubated 1:4 with pooled normal citrated plasma for 5 minutes prior to testing for inhibition of coagulation or with platelet rich plasma prior to assessing their effect on platelet aggregation. All extracts were kept on ice and tested within 1 hour of preparation. Coagulation screening tests using Dade-Behring reagents on a Sysmex CA-1500 coagulometer included PT, APTT, thrombin clotting time, atroxin clotting time, euglobulin clot lysis and anti-Xa assay. Collagen (2μg/ml) and ADP (5μM) were used as inducers of platelet aggregation. The species of leeches examined and their country of origin were:Proboscid LeechesSourceSub-FamilyHaementeria ghilianiiBrazilHaementeriinaeOosthuizobdella garouiSouth AfricaHaementeriinaePlacobdella parasiticaCanadaGlossiphoniinaeJawed LeechesMacrobdella decoraN. AmericaMacrobdellinaeHirudinaria manillensisChinaHirudinariinaeHirudinaria javanicaIndonesiaHirudinariinaePoecilobdella granulosaIndiaHirudinariinaeMyxobdella africanaKenyaPraodbellinaeOur findings indicate that cephalic extracts from all the species examined contain anti-thrombin properties. However, only the giant leech H. ghilianii appears to possess fibrin(ogen)olytic activity. No evidence of a plasminogen activator was detected in any of the extracts. Platelet aggregation responses induced by both agonists were completely inhibited in the presence of all cephalic extracts. No such inhibition was detectable in the posterior musculature control material. Anti-Factor Xa activity was present in extracts from H. ghilianii. Our findings suggest that anti-haemostatic properties in Hirudinea appear to have evolved in response to biological adaptations rather than in keeping with phylogenetic affinities but further work is required to define the precise nature of such mechanisms in related species The different anti-haemostatic properties in these extracts may offer new therapeutic potentials.

Chemical Characters of Two Related Species of Giant Honeybees (Apis dorsata and A. laboriosa): Possible Ecological Significance

The Himalyan honeybee, Apis laboriosa, is sometimes considered to be a form of the rock honeybee, A. dorsata, rather than a separate species. Analyses of potential exocrine compounds produced by both forms revealed that the cephalic and abdominal natural products of these two honeybees shared no common denominators. The sting shaft of workers of A. dorsata is the source of a large series of esters dominated by 1-acetoxy-2-decene. Other major constituents include isopentyl acetate, accompanied by isopentyl propionate, farnesyl acetate, and several other esters. On the other hand, nothing but presumed structural lipids (e.g., ethyl palmitoleate) were identified from sting shafts of workers of A. laboriosa. By contrast, cephalic (including mandibular glands) extracts from workers of A. laboriosa contained γ-octanoic lactone, whereas comparable extracts of A. dorsata workers contained only structural lipids. The major qualitative differences in the chemical characters between A. laboriosa and A. dorsata are consistent with the designation of these two forms as distinct species.

3-methyl-4-phenylpyrrole from the ants Anochetus kempfi and Anochetus mayri.

The cephalic extracts of the ant Anochetus kempfi were found to contain 2,5-dimethyl-3-isoamylpyrazine (1) and 3-methyl-4-phenylpyrrole (2). The structures of these compounds were established from their spectral data and by comparison with synthetic samples. This is the first report of a phenylpyrrole found in an insect and only the third report of a pyrrole from ants.

Phenylalkenals in ponerine(Leptogenys sp.) and myrmicine (Pogonomyrmex sp.) ants

Cephalic extracts of two unrelated species of ants,Leptogenys processionalis andPogonomyrmex rugosus, have been found to contain 2-phenylpropenal and 2-phenyl-2-butenal, while two other species related to the first,L. chinensis andL. kitteli, lacked either.L. kitteli also produced a tetrasubstituted pyrazine found previously only in two New Zealand ants in the genusMesoponera. The chemical reactivity of the phenylalkenals suggests their function in repelling attack by predators.

Exocrine secretions of bees X. 3,7-Dimethyldeca-2,6-dien-1,10-diol: A sex-specific compound fromNomada annulata (Hymenoptera: Anthophoridae)

3,7-Dimethyldeca-2,6-dien-1,10-diol was isolated from male cephalic extracts of the cleptoparasitic or "cuckoo" bee,Nomada annulata. The compound is absent in female head extracts. This diol, previously known only from a male danaid butterfly, is a new bee natural product and is not found in the volatile exocrine secretions of the host bee,Andrena macra. The role of this compound in this parasite-host system, including the chemical basis ofNomada-Andrena associations, is discussed.

Structure and synthesis of tetrasubstituted pyrazines in ants in the genus [formula omitted

The structures of twelve new pyrazines present in Mesoponera species have been elucidated using mass spectrometry and confirmed by synthesis. Ants in the genus Mesoponera are found in the Old World tropics with the exception of two sibling species that occur In New Zealand. M. castanea is found mainly in the North Island whereas M. castaneicolor , characterized by the presence of alate queens, is widely distributed on both islands. In a recent communication we described the poison gland constituents of these ants as a series of simple aliphatic primary and secondary amines ranging from isoamylnonylamine to heptylnonylamine, along with their corresponding formamides, acetamides and isovaleramides. Exclusively in the cephalic extracts, we also noted a series of compounds whose mass spectra in no way resembled the aforementioned substances, and whose nature awaited the accumulation of sufficient extract to allow accurate mass measurement of several ions in one of the peaks. With this data in hand, we have now been able to deduce their structures solely from their mass spectra as an interesting new series of tetrasubstituted pyrazines. Synthesis of several of the compounds confirms our assignments.

Formic acid in caustic cephalic secretions of stingless bee,Oxytrigona (Hymenoptera: Apidae)

The cephalic extracts of two species in the stingless bee genusOxytrigona were analyzed. Extracts made in diethyl ether, and then derivatized with diphenyldiazomethane, revealed large quantities of formic acid, potentially a major defensive secretion of this stingless bee group. We additionally identify several hydrocarbons, aldehydes, ketones, and acetates. Novel diketones identified by others were detected in both species.

Chemistry and functions of exocrine secretions of the antsTapinoma melanocephalum and T. erraticum

Volatile constituents produced by ant workers belonging to the speciesTapinoma melanocephalum andT. erraticum have been analyzed by gas chromatography-mass spectrometry. The pygidial (=anal) gland secretion ofT. melanocephalum is fortified with 6-methyl-5-hepten-2-one and actinidine (the mass spectrum of which is corrected in this paper). An unidentified compound was detected in cephalic extracts. The pygidial gland secretion ofT. erraticum was also dominated by 6-methyl-5-hepten-2-one, in addition to two isomers of iridodial, and iridomyrmecin. The sternal glands contained iridodial and C15-C20 hydrocarbons. Workers ofT. melanocephalum effectively utilize their pygidial gland secretions as an alarm-defense system during aggressive encounters with workers ofSolenopsis geminata. 6-Methyl-5-hepten-2-one is active as a releaser of alarm behavior, and actinidine is repellent to workers ofT. melanocephalum. Cephalic extracts possessed attractant and arrestant properties for workers of this species.

Volatile compounds from ponerine ants in the genusMesoponera

Volatile constituents have been characterized from two species of ponerine ants in the genusMesoponera. 2,5-Dimethyl-3-isopentyl-pyrazine has been identified from cephalic extracts ofM. castanea andM. castaneicolor, by gas chromatography-mass spectrometry. Combined gasters and thoraces of both species are also characterized by the presence of nonanal, nonanoic acid, isovaleric acid, phenylacetic acid, and undecanal, as well as a series of aliphatic amines and amides.N-Isoamylnonylamine was a major constituent that was accompanied byN-isoamylnonenylamine,N,N-diisoamylnonylamine,N-acetyl nonylamine,N-formyl isoamylnonylamine,N-isovaleroyl nonylamine, and several other secondary and tertiary amines. The possible significance of the amines and amides as idiosyncratic natural products ofMesoponera species is discussed.