Venom and Dufour's gland secretions in an Australian species of Camponotus

Constituents of the venom (1) and Dufour's gland (25) have been characterized in an Australian representative of the highly evolved ant subfamily Formicinae. The venom reservoir of this ant, Camponotus intrepidus, contains formic acid, identified as the benzyl ester. The Dufour's gland contains a major hydrocarbon and a minor fatty acid fraction. Hydrocarbons include the normal alkanes, C₁₀ to C₁₇ (82 per cent); two series of monomethylalkanes, C₁₂, C₁₃, C₁₄, C₁₆, and C₁₇, the 3-methyl derivatives comprise approximately 16 per cent, and the 5-methylalkanes 2 per cent of the total; there are trace proportions of the n-alkenes, C₁₂, C₁₃, and C₁₅. The minor fatty acids, myristic, pentadecanoic, palmitic, and stearic are present in the ratio 2 : 2 : 12 : 11.     

Chemical congruence of the complex odoriferous secretions from Dufour's gland in three species of ants of the genus Formica

Forty-six volatile compounds were identified in the secretions from Dufour's gland of worker ants of the species Formica nigricans, F. rufa, and F. polyctena using combined gas chromatography-mass spectrometry and capillary gas chromatography. In both methods the natural volatile material has been driven off excised glands using a precolumn technique.The composition of the secretions from the three species are very similar but there are also some distinct differences, especially between F. nigricans on the one hand and F. rufa and F. polyctena on the other. Straight-chain, saturated hydrocarbons are the quantitatively dominating compounds, with undecane as the largest individual component, followed by tridecane, pentadecane, and heptadecane. Straight-chain, monounsaturated hydrocarbons and methyl-branched, saturated hydrocarbons are also present and a few straight-chain, doubly unsaturated hydrocarbons are present in trace amounts.In the region of lower volatility two isoprenoids identified as all-trans-geranylgeraniol and the corresponding acetate all-trans-geranylgeranyl acetate, have been found together with octadecyl acetate. The relative amounts between these compounds are the main difference between the secretions from the three species. Octadecyl acetate is thus present only in trace amounts in the secretion of F. nigricans.In addition to the compounds mentioned a few aliphatic acetates and alcohols present in small amounts have been identified.The secretions are thought to have many functions which are reflected in their complex composition. This is discussed in comparison with results from other formicine ants. The species specificity in the composition of the secretion from Dufour's gland and the taxonomic value of this specificity are also discussed.     

Dufour's gland secretion of Myrmica rubra: Chemical,electrophysiological, and ethological studies

The major volatile compounds of the Dufour's gland secretion of the ant Myrmica rubra have been identified as acetaldehyde, ethanol, acetone, and butanone, in the approximate ratios of 35:3:40:25, with a total content of 12 ng per gland. Ethological tests have shown that three effects recognized earlier for the Dufour's gland can be attributed to these components. Acetaldehyde synergized by ethanol produces an attractive effect on foraging workers. Acetone induces an increased linear speed, and changes in sinuosity of movement are induced by ethanol synergized by butanone. Ethanol, butanone, or mixtures of all four induce the deposition of Dufour's secretion on the foraging area.     

The volatile components of the mandibular gland secretion of workers of the ants Myrmica lobicornis and Myrmica sulcinodis

The mandibular glands of workers of M. lobicornis produce a mixture of 3-alkanones and 3-alkanols in the C₆–C₁₀ carbon chain length range, in addition to nanogram amounts of acetone, ethanal and 2-methylpropanal. Ethological studies have shown that the three major constituents, 3-octanol, 3-octanone and 3-decanol, are also the major pheromonally active components. When presented together they stimulate an alarm response in the workers similar to that induced by a worker's crushed head.In M. sulcinodis the mandibular gland secretion is composed of a mixture of the same ketones and alcohols, but in different proportions.     

Multiplex real-time PCR detection of P. falciparum, P. vivax and P. malariae in human blood samples

Two duplex real-time PCR assays were developed to diagnose three human parasites: Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae. TaqMan duplex real-time PCR was evaluated in 263 blood samples of suspected malaria patients by comparing results against those obtained with microscopy and nested PCR. Compared with nested PCR, duplex real-time PCR assays showed 100% sensitivity and specificity. Duplex real-time PCR detected all mixtures of P. falciparum and P. vivax DNA, except at threshold detection limits for both parasites in which P. vivax was not amplified. Threshold detection limits of real-time PCR were 3.1, 0.3 and 0.8 parasites per microlitre of blood for P. falciparum, P. vivax and P. malariae, respectively. Duplex real-time PCR allows the detection of malarial cases, including mixed species infection, it simplifies analysis and reduces cost. Thus, this protocol may prove invaluable for use in the diagnosis of human infection, trial treatments and epidemiologic studies in which high-throughput analyses are often required.     

The comparative susceptibilities of Pieris brassicae and P. rapae to a granulosis virus from P. brassicae

A comparison was made of the dosage-mortality responses of larvae of Pieris brassicae and P. rapae to infection by P. brassicae granulosis virus (GV). Bioassays with first, second, third, and fourth-instar larvae of both species revealed a marked difference in susceptibility between instars and between species. Median lethal dosages (LD₅₀s) for P. rapae larvae ranged from five capsules for the first instar to 662 capsules for the fourth instar. With P. brassicae, this range extended from 66 capsules to 2.3 × 10⁷ capsules. The time-mortality responses of the two species were similar when fed virus dosages equivalent to an LD₉₀. Median lethal times (LT₅₀s) ranged from 5 days for first-instar larvae to 7–8 days for fourth-instar larvae. A comparison between a long-established laboratory stock of P. brassicae and a stock recently acquired from the field showed no significant difference in their susceptibility to GV. The implications of the pronounced species differences in susceptibility to GV infection are discussed in relation to the potential field control of P. rapae and P. brassicae.     

Coumarins from Pterocaulon balansae and P. lanatum

Analysis of the petrol-diethyl ether extracts of Pterocaulon balansae and P. lanatum aerial parts afforded, besides puberulin, scopoletin-[2′     

Strongyloides ratti: Dissociation of the rat's protective immunity into systemic and intestinal components

Analysis of the early stages of a challenge infection with Strongyloides ratti has shown that protection is expressed against the developing third-stage larval worms (L₃) and prevents the maturation to adulthood of most larvae. Challenge after an immunizing infection that was restricted to the parenteral L₃ migratory phase showed that some 10–40% of overall protection could be ascribed to systemic antilarval immunity. Some larvae were trapped in the skin at the site of injection whereas others failed to migrate to the head and lung of immune rats. Larvae arriving in the intestine at Days 3, 4, and 5 did not persist beyond Day 7 and 8. Studies using [⁷⁵Se]methionine-labeled L₃ showed a significant increase in fecal label in rats immunized by a complete infection. This loss did not occur to the same extent in rats immunized only with parenteral larvae. Significant rejection of worms transplanted to the intestine also indicated intestinal protection. The possible existence of large numbers of worms in a state of “arrested development” was excluded by their failure to appear after cortisone treatment and the absence of worm accumulation in radiolabeling studies. It is concluded that at least two responses operate against larval S. ratti, one is systemic and the other operates in the intestine against larvae in a manner that resembles the “rapid expulsion” rejection of Trichinella spiralis in immune rats.     

Flavonol tetraglycosides from the leaves of Prunus cerasus and P. Avium

Four new flavonol glycosides have been identified from fresh leaves and fruits of sweet and sour cherries (Prunus avium and P. cerasus) as minor flavonoids: quercetin 3-O-rutinosyl-7,3′-O-bisglucoside; two quercetin 3-O-rutinosyl-4′-di-O-glucosides; kaempferol 3-O-rutinosyl-4′-di-O-glucoside.     

Valyl tRNA's of Anacystis nidulans

Anacystis nidulans was found to contain three tRNA^val isoacceptors which could be charged also in heterologous systems with aminoacyl synth     

Bound forms of alkaloids in Papaver somniferum and P. Bracteatum

The polysaccharide fraction of the pericarp and seed of Papaver somniferum were shown to contain bound forms of morphine which were derived from radioactive morphine fed to living plants. Bound forms of codeine, thebaine and some unidentified alkaloid-like compounds were also detected in the pericarp and bound thebaine occurred in the pericarp of Papaver bracteatum. The complexity and molecular weight of the bound alkaloids seemed to increase during ripening, and it is suggested that these substances represent transitional forms in the metabolism and transiocation of morphine from latex to seed.     

Individual foraging components of harvester ants: movement patterns and seed patch fidelity

Summary We investigated individual foraging components of the western harvester ant,Pogonomyrmex occidentalis, in the native seed background of a shrub-steppe environment. Our study identified factors affecting foraging movements and seed selection by individual ants. Some assumptions and predictions of central-place foraging theory and a correlated random walk were evaluated for individual foragers. Results showed that ant size was only weakly correlated with the seed sizes harvested; seed size was a more important constraint than a predictor of seed selection. Individual ants spent more time in localized search behavior than traveling between search areas and nests.P. occidentalis foragers encountered seeds randomly with respect to time, and handled a mean of 1.7 seeds/trip. A correlation of increased search effort with greater travel distances was consistent with central-place foraging theory but, contrary to it, search and travel effort were not associated with energetic reward.Individual ants exhibited fidelity in both search site and native seed species. Spatial analyses of foraging movements showed a highly oriented travel path while running, and an area-restricted path while searching. Searching ants moved in a manner consistent with a correlated random walk. The deterministic component of patch fidelity and the stochastic component of search may override energetic foraging decisions in individualP. occidentalis ants.     

The complex toxic components of the Russell's viper venom

Russell's viper venom has been fractionated on CM-cellulose, CM-Sephadex and Sephadex gel filtration and disc electrophoresis to obtain 4 toxins one of which is a glycoprotein with 2 subunits, one with 4 cationic subunits one of the subunits being dialysable, one with 3 cationic subunits and a dialysable low molecular weight minor toxin. The specific subunits of individual toxins were found to be necessary for their biological activities.     

The Paxillus involutus (Boletales, Paxillaceae) complex in Europe: Genetic diversity and morphological description of the new species Paxillus cuprinus, typification of P. involutus s.s., and synthesis of species boundaries

Paxillus involutus is a model species for ecological or physiological studies of ectomycorrhizal agaricomycetes. Three to six groups or species linked to it have been ecologically and morphologically distinguished. Phylogenetic studies have revealed the existence of four species in Europe: Paxillus ammoniavirescens, Paxillus obscurisporus, P. involutus, and a fourth as yet not described species. We studied 47 collections from 24 French and Italian locations, supplemented with GenBank data, in order to genetically and taxonomically delineate these species. Phylogenetic analyses of three nuclear DNA regions (rDNA internal transcribed spacer (ITS), tef1-α, and gpd) confirmed the four European species. Morphology, culture, and ecology features allowed us to delineate species boundaries and to describe the fourth species we named Paxillus cuprinus since it turns coppery with age. As there is no existing original herbarium specimen for P. involutus, one of our collections was chosen as the epitype. The low genetic diversity found in P. cuprinus correlates with stable morphological traits (basidiome colour, ovoid–amygdaliform spores with an apical constriction) and with ecological preferences (association with Betulaceae in open and temperate areas). In contrast, P. ammoniavirescens is characterized by a high genetic diversity and a high variation of its morphological and ecological features.     

Serological evidence confirming the assignment of phaseolus aureus and P. mungo to the genus vigna

Endopeptidase activity was detected in extracts of cotyledons of 11 species of Vigna and Phaseolus Antibodies against the purified protease isolated from the cotyledons of 5-day-old P.aureus seedlings inhibited the activity of that enzyme in crude extracts of cotyledons. A similar inhibition was obtained with P. mungo, P. adenanthus and 4 species of Vigna, while there was no inhibition of endopeptidase activity in extracts of cotyledons of 4 species of Phaseolus. Immunodiffusion tests proved that the protease of Vigna is distinct from that of Phaseolus. The evidence supports the reassignment of P. aureus and P. mungo to the genus Vigna and indicates that the names Vigna radiata and Vigna mungo are more appropriate than P. aureus and P. mungo for green gram and black gram respectively.     

Enzymic reduction of codeinone in vitro cell-free systems from Papaver somniferum and P. Bracteatum

Cell-free extracts have been prepared from Papaver somniferum which catalyze the reduction of codeinone-[16-³H] to codeine. The methodology for examining this conversion has pointed to conditions for exploring the preparation of suitable enzyme extracts. P. bracteatum also yielded a cell-free system which reduced codeinone to codeine, both of which are foreign to this species.     

Comparative study of the mandibular gland secretion of four species of Myrmica ants

The mandibular glands of the two species of ant, Myrmica ruginodis and Myrmica sabuleti contain a similar mixture of compounds, but the proportions are different. M. sabuleti produces ethanol, propanone, methylpropanal, 3-hexanone, 3-hexanol, 3-heptanone, 3-heptanol, 3-octanone, 3-octanol, 6-methyl-3-octanone, 6-methyl-3-octanol and 3-decanone. With the exception of 3-decanone these compounds were also found in M. ruginodis. These compounds were also found in M. rubra and M. scabrinodis.In both species now studied, the mandibular gland contents attract the workers and cause a large increase in their linear speed. In M. sabuleti these behavioural activities are due to 3-octanone and 3-octanol: the attraction of these two compounds in a synthetic mixture is exactly like that of an isolated mandibular gland; the compounds act in synergy to cause an increase in the ants' linear speed. Workers of M. ruginodis specifically respond to a mixture of ethanol, 3-octanone and 3-octanol: the alcohol only moderates the ethological action of the ketone, which is a true attractant and causes a very large increase in the ants' velocity; ethanol also attracts workers, acting in this respect in synergy with 3-octanone.These chemical and behavioural results are combined with those previously reported (Cammaerts-Tricot, 1973; Morganet al., 1978) to explain the responses of M. rubra, M. ruginodis, M. sabuleti and M. scabrinodis workers to isolated mandibular glands from each of these four species.