Trimethyl Alkanes Research Articles

Desiccation Resistance and Micro-Climate Adaptation: Cuticular Hydrocarbon Signatures of Different Argentine Ant Supercolonies Across California

Cuticular hydrocarbons (CHCs), the dominant fraction of the insects' epicuticle and the primary barrier to desiccation, form the basis for a wide range of chemical signaling systems. In eusocial insects, CHCs are key mediators of nestmate recognition, and colony identity appears to be maintained through a uniform CHC profile. In the unicolonial Argentine ant Linepithema humile, an unparalleled invasive expansion has led to vast supercolonies whose nestmates can still recognize each other across thousands of miles. CHC profiles are expected to display considerable variation as they adapt to fundamentally differing environmental conditions across the Argentine ant's expanded range, yet this variation would largely conflict with the vastlyextended nestmate recognition based on CHC uniformity. To shed light on these seemingly contradictory selective pressures, we attempt to decipher which CHC classes enable adaptation to such a wide array of environmental conditions and contrast them with the overall CHC profile uniformity postulated to maintain nestmate recognition. n-Alkanes and n-alkenes showed the largest adaptability to environmental conditions most closely associated with desiccation, pointing at their function for water-proofing. Trimethyl alkanes, on the other hand, were reduced in environments associated with higher desiccation stress. However, CHC patterns correlated with environmental conditions were largely overriden when taking overall CHC variation across the expanded range of L. humile into account, resulting in conserved colony-specific CHC signatures. This delivers intriguing insights into the hierarchy of CHC functionality integrating both adaptation to a wide array of different climatic conditions and the maintenance of a universally accepted chemical profile.

Pavement Ant Workers (Tetramorium caespitum) Assess Cues Coded in Cuticular Hydrocarbons to Recognize Conspecific and Heterospecific Non-Nestmate Ants

Most ants live in closed societies from which non-members are excluded through fighting or ritualized displays to protect colony resources. Nestmate recognition is the process by which ants discriminate nestmate from non-nestmate ants. Ants use cues coded in mixtures of long-chain hydrocarbon compounds on the cuticle as nestmate recognition cues. Pavement ants (Tetramorium caespitum) form conspicuous wars between neighboring colonies that are organized after workers meet and make the decision to fight after assessing nestmate recognition cues. These wars involve thousands of individuals. Fighting is ritualized and few ants die in the process. We identified 24 cuticular hydrocarbon compounds, above 1% in relative abundance, in the profile of pavement ants with chain lengths ranging from 15 to 31 carbon atoms. Cuticular lipids contained, in order of abundance: mono-methyl alkanes (45–56%), n-alkanes (range: 16–40% relative abundance), and alkenes (10–20%), with small or trace amounts of di-methyl, tri-methyl alkanes and fatty acids. Results from behavioral tests show that pavement ants assess information in cuticular hydrocarbon profiles to recognize both conspecific and heterospecfic (Pogonomyrmex occidentalis and Camponotus modoc) non-nestmate ants and that the relative abundance of methyl-branched alkanes and alkenes codes for nestmate status, at least for conspecific interactions. Our data add to a growing body of knowledge about how ants use cuticular hydrocarbon based nestmate recognition cues to prevent the intrusion of non-nestmates in to colony space.

Cuticular hydrocarbons in queens, workers and drones of the Indian honeybee Apis cerana indica (Fab.)

AbstractCuticular hydrocarbons (CHCs) have evolved as a communication cues and they play a significant role in the life of social insect. Although the primary function is to prevent desiccation, CHCs are also used in recognition of individuals and insect gregariousness. In this paper we examined the CHCs composition of queens, workers and drones of Apis cerana indica. CHCs analysis by Gas Chromatography – Mass Spectrometry revealed 45 different molecules. In drones, 21–37 carbon chain length hydrocarbons comprising of a complex mixture of alkanes, alkenes, mono-, di-, tri-methyl alkanes and alkadienes were detected. Alkanes of drones resemble those found in workers except pentacosane and triacontane which was not detected in the latter. Workers showed pentacosane, heptacosane, 11-Methyl-heptacosane, 13-Methyl-heptacosane, nonacosane, nonacosene, 13-Methyl-nonacosane and 15-Methyl-nonacosane as major CHCs. Workers had an equal number of straight alkanes and alkenes but differing in their proportions and also containing fewer branched hydrocarbons with chain lengths ranging from 21–37 carbons. Further, workers had significantly higher concentration of nonacosene, pentatriacontene, heptatriacontene as compared to drones. In queens much simpler and straight chain hydrocarbons with carbon chain ranging from 21–37 were detected. Several branched hydrocarbons as compared to drones and workers were absent. Queens had a higher concentration of alkanes than workers and drones.

Analisis Aspek Molekuler Biomarka Alkana Bercabang Core Badak 1/208 Muara Badak, Kutai Kartanegara, Kalimantan Timur

Study compound biomarka branched alkanes on core 1/208 Rhinos have done to contribute to the activities of oil exploration wells 1/208 Muara Badak Badak, East Kalimantan's Kutai Kartanegara-through core biomarka profile branched alkanes. Core samples extracted by alternately with solvent mixture of toluene-methanol (3: 1) and chloroform-methanol (3: 1). Then fractionated by Column Chromatography and Thin Layer Chromatography to obtain aliphatic hydrocarbon fraction. Fractions obtained were identified using Gas Chromatography-Mass Spectrometry.The content biomarka aliphatichydrocarbon fraction were identified, among others, iso and anteiso alkanes, mono and trimethyl alkanes. Compounds iso and anteiso alkanes, and alkyl alkane other, providing information that the source of organic material core samples I and II is derived from microorganisms prokaryotic or biogenic precursor derived from cyanobacteria (marine microorganisms) and homologous monomethyl alkanes found in core samples II closer homologous series monomethyl alkanes found in sediments and oil and Precambrian Proterozoic era, so it can be said that the core sample II core samples older than I.

Octane enhancement by the selective separation of branched and linear paraffins in naphthas using a PVDC-PVC carbon molecular sieve

Silicalite-1 samples and PVDC based Carbon Molecular Sieve (CMS-IMP12) material were compared in the separation of linear and multi-branched paraffins present in a real feedstock by fixed bed adsorption experiments. The CMS-IMP12 material was obtained from the pyrolysis of a poly-(vinylidene choride-co-vinyl chloride) (PVDC-PVC) polymer commercially known as Saran™. Material balances of the breakthrough experiments showed higher adsorption capacities for the CMS-IMP12 (5.4–8.8g/100g-adsorbent) than for silicalite-1 (1.2–3.4g/100g-adsorbent) at the temperature range studied (175–325°C). Additionally, the octane number increment for the CMS-IMP12 was at least 4 units higher for the same amount of recovered non-adsorbed fraction (1.5g/100g-adsorbent). In order to simplify the description of the hydrocarbon mixture, the alkanes were classified according to their degree of branching as: linear, monomethyl, dimethyl (non-gem), dimethyl (gem) and trimethyl alkanes. Similarly, cycloalkanes as: non-branched (cyclopentane and cyclohexane), monomethyl, dimethyl (non-gem), dimethyl (gem) and trimethyl cycloalkanes, where gem refers to the relationship between two methyl groups that are attached to the same carbon atom. The CMS-IMP12 was able to separate gem-dimethylalkanes, gem-dimethylcycloalkanes and trimethylalkanes, while silicalite-1 was less selective.

Learning and discrimination of cuticular hydrocarbons in a social insect

Social insect cuticular hydrocarbon (CHC) mixtures are among the most complex chemical cues known and are important in nest-mate, caste and species recognition. Despite our growing knowledge of the nature of these cues, we have very little insight into how social insects actually perceive and discriminate among these chemicals. In this study, we use the newly developed technique of differential olfactory conditioning to pure, custom-designed synthetic colony odours to analyse signal discrimination in Argentine ants, Linepithema humile. Our results show that tri-methyl alkanes are more easily learned than single-methyl or straight-chain alkanes. In addition, we reveal that Argentine ants can discriminate between hydrocarbons with different branching patterns and the same chain length, but not always between hydrocarbons with the same branching patterns but different chain length. Our data thus show that biochemical characteristics influence those compounds that ants can discriminate between, and which thus potentially play a role in chemical signalling and nest-mate recognition.

Cuticular Hydrocarbons Provide Reliable Cues of Fertility in the Ant Gnamptogenys striatula

In ca. 150 species of queenless ants, a specialized queen caste is rare or absent, and mated workers take over the role of the queen in some or all of the colonies. Previously, it has been shown that reproduction in queenless ants is regulated by a combination of dominance behavior and chemical fertility signaling. It is unknown, however, whether chemical signals alone can sufficiently regulate reproduction. To investigate this possibility, we studied reproductive regulation in the facultatively queenless ant Gnamptogenys striatula, a species where dominance behavior is rare or absent. Active egg layers and infertile workers showed qualitative and quantitative differences in their cuticular hydrocarbon profile. Five long-chain methyl alkanes, 3,13- and 3,15-dimethyl pentriacontane, 3,13- and 3,15-dimethyl heptentriacontane, and 3,11,15-trimethyl heptentriacontane occurred only on the cuticles of virgin and mated egg layers. Pronounced quantitative differences were found in a further 27 alkenes; alkanes; and mono-, di-, and trimethyl alkanes. Workers that had recently stopped laying eggs had profiles similar to infertile workers, and mating status did not affect this chemical pattern. We conclude that the cuticular hydrocarbon profiles of G. striatula workers provide reliable information about their current fertility. In the interest of colony productivity, this allows reproduction to be regulated without the use of aggression.

Stage-specific surface chemicals of Plodia interpunctella: 2-acyl-1,3-cyclohexanediones from larval mandibular glands serve as cuticular lipids

Cuticular lipid compositions of all life stages of the stored product moth Plodia interpunctella have been determined. Eggs and adults of P. interpunctella have cuticular lipids consisting solely of hydrocarbons. The composition of eggs and adult females is qualitatively nearly identical with ca. 86 hydrocarbons (11 n-alkanes, 39 monomethyl alkanes, 19 dimethyl alkanes, 11 trimethyl alkanes and 6 monoenes) except females lack the 2-methyl alkanes found in eggs. Adult males have a hydrocarbon composition qualitatively nearly identical to females with the exception that they lack the monoenes. Larval and pupal cuticular lipids are dominated by a mixture of ca. 20 previously described 2-acyl-1,3-cyclohexanediones, with only minute amounts of n-alkanes on the larvae and pupae. The 2-acyl-1,3-cyclohexanediones are continuously secreted onto their silk webbing and food particles by the paired mandibular glands found in all larvae. Extracts from dissected mandibular glands have a qualitatively identical composition to larval cuticular extracts. The pupal stage (which does not have mandibular glands) is enclosed in a silk cocoon also coated with 2-acyl-1,3-cyclohexanediones laid down while the wandering stage larvae spin the cocoon. The 2-acyl-1,3-cyclohexanediones have physical properties which closely mimic those of cuticular hydrocarbons, including melting point and boiling point range and hydrophobicity. This is the first report of an insect with a life stage that does not use conventional cuticular lipids for conservation of water.

Hydrocarbons in adult Chrysomela vigintipunctata (Scopoli) (Coleoptera: Chrysomelidae)

The hydrocarbon composition of the willow leaf beetle Chrysomela vigintipunctata (Scopoli) (Coleoptera: Chrysomelidae) is presented in this paper. Surface and internal hydrocarbons, total hydrocarbons of fed and starved insects, of the excrement and of the diet have been examined and compared. Normal chain-, terminally branched monomethyl-, internally branched monomethyl-, dimethyl-, trimethyl alkanes and only four alkenes have been identified in the insect. The chain-lengths varied in the interval C 19 to C 43. Odd chain alkanes dominate. Surface hydrocarbons are characterised by the presence of longer-chain (C 38,C 39 and C 41) dimethyl- and trimethyl-alkanes. Dimethyl- and trimethyl alkanes with an unusually great number of methylene groups between the branch points have been detected. The excrement and the willow leaves have much simpler HC pattern: n-alkanes, terminally branched alkanes and alkenes. Based on the similarity between the HC pattern of the excrement and willow leaves it is assumed that the dietary HC are eliminated with the excrement.

BIODEGRADATION OF JET FUEL A1 RECOVERED FROM POLLUTED SOIL

ABSTRACT The purpose of this work is to study the biodegradation of Jet Fuel A1 (Jet Al). The samples were recovered from a polluted ground. The first step was to characterize all remaining compounds by gas chromatography/flame ionized detection (GC/FID). The lineal hydrocarbons detected were split from nonane to tetradecane. The branched hydrocarbons found were mono-, di- and trimethyl alkanes. Degradation of Jet A1 was carried out by the local ground microorganisms and also in the laboratory by using a trade product called Putidoil. Several degradation accelerators were employed. In most samples, degradation levels were up to 90%.

Cuticular Hydrocarbons of the Host-Specific Ectoparasitoid Cephalonomia stephanoderis (Hymenoptera: Bethylidae) and Its Host the Coffee Berry Borer (Coleoptera: Scolytidae)

Cuticular hydrocarbons have been identified from larvae and adults of the bethylid wasp Cephalonomia stephanoderis Betrem and larval, prepupal, pupal, and adult stages of its host, the scolytid beetle Hypothenemus hampei (Ferrari). Larval, male and female wasps have the same cuticular hydrocarbons, but in different relative abundances. The major components of adults are n-alkanes (C21−C33), monomethyl alkanes (3-, 5-, 7-, 9-, 10-, 11-, 12-, 13-, 14-, 15-, 16-, and 17-methyl), and Z-(10)-monomethyl alkenes (with the methyl branch at C14−C19). Minor components include a series of 3,X-; 4,X-; 5,X-; 6,X-; 7,X-, and 8,X- dimethyl alkanes (with X at C14−C19) and a series of 3,9,13- and 3,11,15-trimethyl alkanes. Male C. stephanoderis are characterized by high proportions of n-alkanes and lower proportions of the monomethyl alkanes and methylbranched alkenes. Female wasps are characterized by lower proportions of n-alkanes and higher proportions of the monomethyl alkanes and methylbranched alkenes. Larval C. stephanoderis are characterized by high proportions of the methylbranched components and lower proportions of the n-alkanes and the n- and methylbranched alkenes. Host scolytid beetle cuticular hydrocarbons are totally saturated. Major components of all stages and sexes include n-alkanes (C22 − C31), monomethyl alkanes (3-, 4-, 5-, 13-, 14-, 15-, 16- and 17-methyl), a series of dimethyl alkanes (3,7-; 3,9-; 3,15-; 3,17-; and 3,19-), and a series of trimethyl alkanes (3,7,13-; 3,9,13-; and 3,11,15-). Minor components are a series of 4,14- and 4,16-dimethyl alkanes and 5,17- and 5,19-dimethyl alkanes. All immature beetle stages had similar hydrocarbon compositions, which differed moderately from those of the adults. As with the adult wasps, relative compositions of male and female beetles differed. Males were characterized by a greater proportion of n-alkanes and lesser proportions of monomethyl alkanes and trimethyl alkanes. Females had lesser proportions of n-alkanes and greater proportions of monomethyl alkanes and trimethyl alkanes. The cuticular profiles of the parasitoid and host are compared and discussed in terms of both intraspecific and interspecific semiochemical interactions.

Role of cuticular hydrocarbons of aphid parasitoids in their relationship to aphid-attending ants

Lysiphlebus cardui, the dominant aphidiid parasitoid of the black bean aphid,Aphis fabae cirsiiacanthoidis (Afc), on creeping thistle, is able to forage in ant-attended aphid colonies without being attacked by ants. Several behavioral observations and experimental studies led to the hypothesis thatL. cardui mimics the cuticular hydrocarbon profile of its host aphid. Chemical analysis of the cuticular extracts revealed that bothL. cardui and Afc exclusively possess saturated hydrocarbons:n-alkanes, monomethyl (MMA), dimethyl (DMA), and trimethyl alkanes (TMA). Comparison of the hydrocarbon profiles of parasitoid and aphid showed great qualitative resemblance between parasitoid and host:L. cardui possesses almost all host-specific compounds in addition to species-specific hydrocarbons of mainly higher molecular weight (>C30). However, there is a lesser quantitative correspondence between parasitoid and host aphid. Furthermore, we analyzed the cuticular hydrocarbon profile of another parasitoid of Afc,Trioxys angelicae. This aphidiid species is vigorously attacked and finally killed by honeydewcollecting ants when encountered in aphid colonies. Its cuticular hydrocarbon profile is characterized by the presence of large amounts of (Z)-11-alkenes of chain lenghts C27, C29, C31, and C33, in addition to alkanes and presumably trienes. The role of the unsaturated hydrocarbons onT. angelicae as recognition cues for aphid-attending ants is discussed.

Occurrence and origin of mono-, di-, and trimethylalkanes in modern and Holocene cyanobacterial mats from Abu Dhabi, United Arab Emirates

n-Alkanes, highly branched isoprenoids, monomethylalkanes (MMAs), dimethylalkanes (DMAs), and trimethylalkanes (TMAs) are the most abundant components in the hydrocarbon fractions of extracts of four modern and two Holocene cyanobacterial mats (t̃1500 and 5110 ± 170 y bp) collected in Abu Dhabi (United Arab Emirates). The homologous families of MMAs, DMAs, and TMAs were identified by comparison of mass spectral and relative retention time data with published data. DMAs were also identified by synthesis of authentic standards, 3,9-dimethyltricosane, 5,9-dimethyltricosane, and 11,15-dimethylheptacosane. MMAs, DMAs, and TMAs of the cyanobacterial mats can be separated into two groups on the basis of their distribution patterns and structures. MMAs and DMAs in the C16-C22 range are characterized by methyl substituents mainly located at C-6 (or ω6) and C-7 (or ω7) and are derived from cyanobacteria. They are relatively abundant components in the modern cyanobacterial mats, but with increasing age of the mats they become much less abundant. On the contrary MMAs, DMAs, and TMAs in the C24-C45 range are exclusively found in the Holocene cyanobacterial mats. Their longest chains mainly contain an odd number of carbon atoms and they always carry the methyl substituents at odd numbered carbon atoms. The similarity in composition of this very specific group of branched alkanes with that encountered in insect epicuticular waxes suggests that these sedimentary hydrocarbons originate from insects, which probably grazed on the cyanobacterial mats.