Regional variation in cuticular hydrocarbon composition in the common house cricket,Acheta domesticus

• 1.1. The hydrocarbon composition of different cuticular regions (pronotum, legs, abdominal tergites and sternites, pleural membrane) was determined for adult female crickets (Acheta domesticus).
• 2.2. Hydrocarbon groups included n-alkanes, 2-methylalkanes, long-chain internally branched monomethyl- and dimethyalkanes, n-alkenes, 2-methylalkenes and alkadienes.
• 3.3. Saturated hydrocarbons were more abundant than unsaturated hydrocarbons and branched saturates more abundant than n-alkanes in all regions of the cuticle examined.
• 4.4. Except for a higher percentage of n-alkanes in the pleural membrane (soft cuticle), little difference was noted in compositional patterns or relative amounts of individual molecules from the different cuticular regions.

     

Characterization and discrimination of three Rhopalosiphum species (Homoptera: aphididae) using cuticular hydrocarbons and cuticular surface patterns

• 1.1. Cuticular hydrocarbons of two clones of Rhopalosiphum maidis, two of R. padi, one of R. insertum, and one of Schizaphis graminum were identified as n-alkanes, monomethylalkanes and dimethylalkanes.
• 2.2. No qualitative differences in hydrocarbon content were apparent among the six aphid populations studied; however, hydrocarbon profiles were discriminatory.
• 3.3. Discriminant analysis of the proportions of the cuticular hydrocarbons selected 29 hydrocarbon components that provided discrimination among populations except for the two R. padi clones which were indistinguishable.
• 4.4. Scanning electron micrographs showed very clear differences in the cuticular surface patterns among the three Rhopalosiphum species.

     

The compositoin of cuticular hydrocarbons of the cereal aphids Sitobion avenae F. (Homoptera,Aphididae)

• 1.1. The cuticular hydrocarbons of the cereal aphids, Sitobion avenae F. were studyed by capillary column chromatography and mass spectrometry.
• 2.2. n-Alkanes, 2-, 3-, 4-, 5-, 6-, 10-, 11-, 12- and 13-monomethylalkanes, 7,11-, 11,15-, 13,17- and 5,11-dimethylalkanes were found in cuticular lipids.
• 3.3. The results obtained are significantly different from these of pea aphid, where only n-alkanes were found.
• 4.4. The n-alkanes of cereal aphids range from 23 to 35 carbon atoms with the predominance of odd over even members.
• 5.5. These are terminally branched hydrocarbons 2-methyl and 3-methyl-alkanes rarely found together in cuticular lipids of insects.

     

Cuticular hydrocarbons of adult Blaps mucronata latereille (coleoptera: tenebrionidae)

• 1.1. The cuticular hydrocarbon mixture of Blaps mucronata comprises n-alkanes (C₂₃ to C₂₉, 41%), 3-methylalkanes (C₂₄ to C₃₂, 29%) and internally branches monomethylalkanes (C₂₄ to C₃₆, 11%) and dimethylalkanes (C₃₂ to C₃₇, 15%).
• 2.2. B. mucronata is distinguished from six other tenebrionid species by the qualitative and quantitative characteristics of its hydrocarbon mixture.

     

Characterization of Colorado potato beetle lipophorin: A hydrocarbon-rich diacylgycerol-poor lipophorin

• 1.1. The lipid composition of lipophorin from the Colorado potato beetle, Leptinotarsa decemlineata Say, was analyzed.
• 2.2. This insect lipophorin contains 44% lipid and is characterized by large amounts of hydrocarbons and small amounts of diacylglycerol.
• 3.3. This is the first observation of a diacylglycerol-poor insect lipophorin in haemolymph.
• 4.4. Since the main energy source for flight in the Colorado potato beetle is proline, the low diacylglycerol content in lipophorin must be related to its peculiar flight metabolism.
• 5.5. This lipophorin, however, can still take up appreciable amounts of diacylglycerol from the locust fat body. Hydrocarbon uptake by this lipophorin was also demonstrated.
• 6.6. The main function of this lipophorin therefore seems to be transport of hydrocarbons from oenocytes to the cuticle.

     

Cuticular hydrocarbons,social organization and ovarian development in a polistine wasp: Polistes dominulus christ

• 1.1. The cuticular hydrocarbons of the wasp, Polistes dominulus, are linear branched, saturated alkanes, mainly monomethylalkanes.
• 2.2. The foundress can be distinguished from her offspring by differences in the relative proportions of some alkanes and monomethylalkanes, which were the same in all the foundresses studied here. The ovarian state is linked to the cuticular spectrum since these constituents were present in similar proportions in a foundress and in a descendant with comparably developed ovaries.
• 3.3. In some, but not all cases, it was possible to discriminate between descendants originating from different foundresses on the basis of other hydrocarbons belonging to all the chemical families present.
• 4.4. No correlations were observed between the descendants' behavioural profiles and the cuticular hydrocarbon spectra.

     

Comparative analysis of cuticular hydrocarbons in the Drosophila virilis species group

• 1.1. Chemical structures were determined for the cuticular alkanes, alkenes, and certain of the alkadienes for 11 D. virilis group species.
• 2.2. Male-specific hydrocarbons occurred in five species: these were 9-heneicosene in D. americana and D. novamexicana, 10-heneicosene in D. virilis, 5,13- and 5,15-pentacosadienes in D. kanekoi, and 9-pentacosene in one strain of D. lummei.
• 3.3. Hydrocarbon profiles of newly emerged flies always differed from mature files.
• 4.4. Relationships among the species, with respect to hydrocarbon profiles, were investigated by cluster analysis.

     

Respiratory gas concentrations in the microhabitats of some florida arthropods

• 1.1. The concentrations (dry gas %) of oxygen and carbon dioxide were measured in a variety of microhabitats of arthropods in Florida: at the ends of the burrows of three spider species (Sphodros abboti, Geolycosa micanopy, Cyclocosmia torreya) and a tiger beetle (Megacephala carolina) larva, within ant (Solenopsis invicta) mounds, within stumps inhabited by termites (Reticulitermes flavipes), and within and under decaying hardwood logs.
• 2.2. Hypoxia and hypercarbia occurred in all microhabitats, with the ratio of oxygen decrement to carbon dioxide increment close to one. Changes for both gases were minor in the spider burrows, under decaying logs, and within ant mounds (<2.3% for O₂ and 1.1% for CO₂) and are probably physiologically unimportant to their inhabitants.
• 3.3. In contrast, %O₂ fell to as low as 12–14%, and CO₂ rose to as high as 6–8%, in the burrows of tiger beetle larvae, within decaying logs, and inside decaying stumps inhabited by termites.
• 4.4. Such changes, particularly for CO₂ may present a challenge to organisms living in these microenvironments.
• 5.5. Approximately 20–25% of the changes in the concentrations of respiratory gases in the burrows of tiger beetle larvae are attributable to the metabolism of the larva, the remainder being due to diffusional exchanges with the soil.

     

Cuticular hydrocarbons of Drosophila virilis: Comparison by age and sex

The cuticular hydrocarbons of Drosophila virilis were isolated and identified by TLC, GC, HPLC, GC-MS and ozonolysis-GC techniques. The major classes of hydrocarbons in both sexes were 2-methylalkanes, (Z)-11- and (Z)-13-alkenes, and a mixture of n-(Z,Z)-alkadienes. The key isolation step for the alkadienes was high pressure liquid chromatography on a silver nitrate impregnated silica column. The silver nitrate-silica column afforded separation of the alkadienes based primarily on number of carbons between the double bonds. The most abundant alkadienes had double bonds separated by six methylene units, but alkadienes with 2, 8, 10 and 12 methylenes between double bonds were also present.The cuticular hydrocarbons of adult D. virilis changed dramatically in quantity and composition between eclosion and 8 days of age:

• 1.1. The quantity of total hydrocarbons of flies of both sexes increased by 3-fold between the ages of 0 and 4 days. Between 4 and 8 days of age, the quantity on females remained unchanged, but on males there was an additional 2-fold increase in quantity of total hydrocarbons.
• 2.2. With increased age the average chain length of the hydrocarbons decreased.
• 3.3. (Z)-10-Heneicosene, exclusively from male flies, was absent at eclosion, started to appear at about 4 days of age, and amounted to over half of the total hydrocarbons on 8-day-old male flies.
• 4.4. Although no differences in (Z)-11-pentacosene between sexes were observed at 4 days old, (Z)-11-pentacosene on 8-day-old females was nearly 3 times more abundant than on 8-day-old males.

     

Water relations and thermal sensitivity of several cockroach species (Dictyoptera: Blattidae and blaberidae)

• 1.1. Per cent total body water content (%TBW), cuticular permeability (CP), rate of water loss, critical thermal maxima (CTMax), and upper lethal limits (ULL) were determined for Pacific beetle, Diploptera punctata (Eschscholtz), Surinam, Pycnoscelus surinamensis (L.), and Turkestan, Blaita lateralis (Walker), cockroaches.
• 2.2. Initial body mass ranged from 153.16 to 464.96 mg, for D. punctata and P. surinamensis cockroaches, respectively. Mean %TBW was 57.8 for P. surinamensis and 67.7 for B. lateralis.
• 3.3. Mean cuticular permeability was not related to initial mass and ranged from 20.9 to 38.7 μg/cm²/hr/mmHg for D. punctata and P. surinamensis, respectively.
• 4.4. Cumulative mass loss and %TBW lost increased linearly with desiccation time.
• 5.5. CTMax ranged from 43.2°C for D. punctata to 44.3°C for P. surinamensis. There were significant, but small differences in CTMax among the three species.
• 6.6. ULL were 2.2 to approximately 4°C greater than CTMax. The greatest ULL was 48.1°C for B. lateralis and the lowest ULL was 45.0°C for D. punctata.

     

The influence of aerial exposure on gas exchange and cardiac activity in the shore crab,Carcinus maenas (L.)

• 1.1. The cardiovascular physiology of adult Carcinus maenas (L.) emerging into air has been investigated at three different air temperatures.
• 2.2. Transition from seawater to air or vice versa triggered transient increases in cardiac and locomotor activity.
• 3.3. However, crabs became inactive 5–10 min after emerging from seawater (15°C) into air at the same temperature (15°C) or at lower temperatures (12–13°C) and heart rate fell.
• 4.4. At higher air temperatures (18–20°C) heart rate rose but to a lesser extent than predicted from aquatic Q₁₀ heart-rate values.
• 5.5. Crabs were again quiescent in aerial conditions.
• 6.6. Mean arterial oxygen tension (Pa_o2) was ~ 74 mmHg in submerged crabs but fell to ~ 38 mmHg in air while mean arterial carbon dioxide tension (Pa_o2) increased from 1 to 4 mmHg resulting in respiratory acidosis.
• 7.7. A model of gill function is proposed to explain the development of internal hypoxia in air.
• 8.8. The results are discussed in relation to the distribution of adult and juvenile C. maenas in situ.

     

The dufour gland substances of the workers of Formica fusca and Formica lemani (hymenoptera: formicidae)

• 1.1. The Dufour gland secretions of Formica fusca consist mainly of saturated straight and branched chain hydrocarbons (C₉–C₁₉), one unsaturated hydrocarbon (C₁₃) and two sesquiterpenoids, farnesene and homofarnesene.
• 2.2. In F. lemani, the Dufour gland contains branched, saturated and unsaturated hydrocarbons (C₉–C₁₉) and two farnesenes.
• 3.3. The two species were distinguished chiefly by the presence of a relatively large proportion of farnesene in F. fusca, with very little homofarnesene and by contrast, little farnesene but much more homofarnesene in F. lemani.
• 4.4. The contents of the Dufour gland can be used as a chemotaxonomic clue to distinguish between the species.

     

IDentification of a microsomal retinoic acid synthase as a microsomal cytochrome P-450-linked monooxygenase system

• 1.1. To characterize an enzyme which metabolizes retinal in liver microsomes, several properties of the enzymatic reaction from retinal to retinoic acid were investigated using rabbit liver microsomes.
• 2.2. The maximum pH of the reaction in the liver microsomes was 7.6.
• 3.3. The K_m and V_max values for all-trans, 9-cis and 13-cis-retinals were determined.
• 4.4. The reaction proceeded in the presence of NADPH and molecular oxygen.
• 5.5. The incorporation of one atom of molecular oxygen into retinal was confirmed by using oxygen-18, showing that the reaction comprised monooxygenation, not dehydrogenation.
• 6.6. The monooxygenase activity was inhibited by carbon monoxide, phenylisocyanide and antiNADPH-cytochrome P-450 reductase IgG, but not by anti-cytochrome b₅ IgG.
• 7.7. The enzymatic activity inhibited by carbon monoxide was photoreversibly restored by light of a wavelength of around 450 nm.
• 8.8. The retinal-induced spectra of liver microsomes with three isomeric retinals were type I spectra.
• 9.9. The microsomal monooxygenase activity induced by phenobarbital or ethanol were more effective than that by 3-methylcholanthrene, clotrimazole or β-naphthoflavone.
• 10.10. These results showed that the monooxygenase reaction from retinal to retinoic acid in liver microsomes is catalyzed by a cytochrome P-450-linked monooxygenase system.

     

The occurrence of brassicasterol and epibrassicasterol in the chromophycota

• 1.1. Sterols were identified from eight isolates of five species in the Chromophycota that were cultured axenically and harvested in the stationary phase.
• 2.2. Analyses were performed on four strains from the Prymnesiophyceae, two strains from the Cryptophyceae and one from the Bacillariophyceae. Most strains examined contained only one major sterol, 24-methyl-22-dehydrocholesterol.
• 3.3. Analysis by capillary GC, HPLC, and in one instance NMR, showed that the two strains provisionally identified as Isochrysis contained brassicasterol (24β-methyl-22-dehydrocholesterol); whereas, all other species examined contained primarily epibrassicasterol (24α-methyl-22-dehydrocholesterol).
• 4.4. Stigmasterol (24α-ethyl-22-dehydrocholesterol) accompanied epibrassicasterol in Pleurochrysis carterae.
• 5.5. Analyses of C-24 alkyl isomers in these algae may provide useful information concerning their taxonomic placement.
• 6.6. The occurrence of both isomers of 24-methyl-22-dehydrocholesterol in oysters is explained by the occurrence of both isomers among algae which are probably dietary sources for oysters.

     

Partial purification of rat liver cytoplasmic acetyl-CoA synthetase; Characterization of some properties

• 1.1. Rat liver cytoplasmic acetyl-CoA synthetase was partially purified (purification factor = 23, yield = 30%).
• 2.2. The apparent K_ms for acetate, coenzyme A, ATP and MgCl₂ were determined and found to be 52.5 μM, 50.5 μM, 570 μM and 1.5 mM, respectively.
• 3.3. The partially-purified enzyme showed a low affinity for short-chain carbon substrates other than acetate.
• 4.4. The properties of the partially-purified enzyme were compared with those of enzymes from other sources.

     

A simple and reliable method for the purification of Pseudomonas aeruginosa phospholipase C produced in a high phosphate medium containing choline

• 1.1. Pseudomonas aeruginosa phospholipase C from culture supernatants of bacteria grown in high-P_i basal salt medium with choline, as the sole carbon and nitrogen source, was purified by precipitation with 70% saturation ammonium sulfate in the presence of celite.
• 2.2. The PLC activity was eluted of this mixture by the use of a reverse gradient of 70-0% ammonium sulfate.
• 3.3. The peak containing the PLC activity revealed a single protein after SDS-PAGE.
• 4.4. The method could also be applied to purify PLC produced in a low-P_i complex medium. The resultant preparation was not homogeneous.
• 5.5. The molecular weight for both PLC preparations was about 70 kDa.
• 6.6. Both PLC used phosphatydilcholine and sphingomyelin as substrates, displayed hemolytic activity an exhibited an apparent K_M of 25 mM for p-nitrophenylphosphorylcholine.
• 7.7. They were not inhibited by 1% sodium deoxycholate but were 30% inhibited by 1% Triton X-100.
• 8.8. 2% sodium dodecylsulfate and 1% tetradecyltrimethylammonium bromide inhibited the PLC from the HP_l-BSM plus choline but not the enzyme from the LP_l-CM.

     

Thermal properties for digestive enzymes of a sub-antarctic beetle,hydromedion sparsutum (coleoptera,perimylopidae) compared to those in two thermophilic insects

• 1.1. Proteolytic, lipolytic, amylolytic and cellulolytic activities were studied in adults of the phytophagous beetle, Hydromedion sparsutum, indigenous to the sub-Antarctic island of South Georgia.
• 2.2. Gastric enzyme activities were measured at experimental temperatures of 5–40°C and results were compared with those obtained from two thermophilic insects, Gryllus bimaculatus and Tenebrio molitor.
• 3.3. Protease and lipase activities in Hydromedion were 10–15 times lower than in Gryllus and Tenebrio.
• 4.4. In the temperature range of 5–15°C, α-amylase activity from Hydromedion was only slightly lower than that from Gryllus.
• 5.5. Hydromedion gut homogenates exhibited a distinct cellulolytic activity, even at a low temperature of 5°C.
• 6.6. Cellulolytic activity in the digestive tract of Hydromedion was confirmed by the evolution of ¹⁴CO₂ after consumption of labelled cellulose.
• 7.7. The thermal properties of digestive enzymes agree well with the role of Hydromedion as primary decomposer in its ecosystem.

     

Comparative analysis of dufour's gland secretions of two carpenter bees (xylocopinae: anthophoridae) with different nesting habits

• 1.1. The chemistry and function of Dufour's gland secretions of two carpenter bees were studied.
• 2.2. Dufour's gland of Proxylocopa olivieri, a ground nesting bee, produces long chain hydrocarbons that are utilized to line its brood cells and are mixed with its bee bread.
• 3.3. Dufour's gland secretion of Xylocopa sulcatipes, on the other hand, is dominated by ethyl eicosanoate and ethyl docosanoate accompanied by the corresponding methyl esters and high boiling hydrocarbons.
• 4.4. This wood nesting bee apparently does not use Dufour's gland secretion to line its nest.
• 5.5. The relationship between the respective chemistry and function of Dufour's gland secretion and the nesting ecology of the two bees is discussed.

     

Entomopathogenic fungal infection (Deuteromycotina: Hyphomycetes) affects water relations of the german cockroach,Blattella germanica (L.) (Dictyoptera: Blattellidae)

• 1.1. The total body water, lipid content, and cuticular permeability of fungus infected and uninfected German cockroaches, Blattella germanica, were examined.
• 2.2. Infected adult cockroaches weighed less and had significantly more body water than did uninfected specimens of the same size.
• 3.3. Uninfected medium-size nymphs weighed significantly more than infected nymphs, but there was no difference in body size between infected and uninfected small nymphs.
• 4.4. Cuticular permeability and lipid content of infected and uninfected cockroaches was not significantly different.
• 5.5. Sequestering of water by the fungal cells is discussed as a possible factor in the pathology of this fungal parasite.

     

Metabolic rates of Calathus melanocephalus (L.) (coleoptera,carabidae) from alpine and lowland habitats (jeløy and finse,norway and drenthe,the netherlands)

• 1.1. Metabolic rates (ml O₂/mg/hr) of three geographically separated populations of the carabid beetle Calathus melanocephalus L. (Finse and Je 10y, Norway and Drenthe, The Netherlands) were measured and compared by ANCOVA.
• 2.2. No significant relationship (P > 0.05) between metabolic rates and body weight or sex of the animals were found.
• 3.3. Individuals mostly acclimated to low temperatures by increased metabolic rates and in the opposite direction to higher temperatures. Individuals collected in early summer also showed higher metabolic rates than those caught later in the autumn.
• 4.4. Contradicting the theory of metabolic cold adaptation, beetles from The Netherlands had the highest metabolic rates, beetles from Finse intermediate rates and beetles from Jeløy the lowest rates.
• 5.5. No significant relation were found between geographical origin of the beetles and their respective chill-coma temperature.