Sex Pheromone and Trail Pheromone of the Sand Termite <Emphasis Type="Italic">Psammotermes hybostoma</Emphasis>

Within the complex network of chemical signals used by termites, trail pheromones and sex pheromones are among the best known. Numerous recent papers map the chemical identity and glandular origin of these pheromones in nearly all major isopteran taxa. In this study, we aimed to describe the sex pheromone and the trail pheromone of a poorly known sand termite, Psammotermes hybostoma. We identified (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol (dodecatrienol) as the sex pheromone released by tergal and sternal glands of female imagos and, at the same time, as the trail pheromone secreted from the sternal gland of workers. We conclude that chemical communication in Psammotermes does not differ from that of most other Rhinotermitidae, such as Reticulitermes, despite the presence of a diterpene as a major component of the trail pheromone of Prorhinotermes to which Psammotermes is presumed to be phylogenetically close. Our findings underline once again the conservative nature of chemical communication in termites, with dodecatrienol being a frequent component of pheromonal signals in trail following and sex attraction and, at the same time, a tight evolutionary relationship between the trail following of working castes and the sex attraction of imagos.     

Improvement of tribological properties of stainless steel by alloying its surface layer with rare earth elements using high intensity pulsed plasma beams

Austenitic stainless steels are widely used in numerous industrial applications due to their excellent corrosion resistance. However some applications are limited in cases when due to low hardness and poor tribological properties of stainless steel wear is responsible for the durability of a given engineering component.In the present work we have undertaken an attempt to improve the wear resistance of AISI 316L steel by alloying its near surface region with rare earth elements—REE using high intensity pulsed plasma beams in so called deposition by pulse erosion (DPE) mode. Power density of pulses was 10⁶–10⁷ W/cm² with the pulse duration in μs range. Heating and cooling processes were of non-equilibrium type. The near surface layer—thickness in μm range—was melted and simultaneously doped with cerium and lanthanum. Various parameters of the process were set up to get level of doping between 0.3 and 2.8 at.% REE.An improvement of tribological properties—linear wear and scratch resistance—with increasing REE concentration as compared to the initial material was observed.     

Oxidation and adsorption of arsenic species by means of hybrid polymer containing manganese oxides

The aim of this work was a comprehensive study of the oxidative and sorptive properties of a hybrid polymer containing manganese oxide toward As(III) and As(V). A poly(styrene‐divinylbenzene) copolymer containing oxidative functional groups (? SO₂NBrNa) was used as the supporting material for MnO₂. The inorganic component was deposited as a result of the oxidation reaction of Mn(II) with oxidative groups of the host polymer. The surface of the polymer matrix was evenly covered with a thin layer of manganese oxide. The obtained product (R/S/Mn) exhibited high oxidative capacity over a wide pH range (2–12); however, under acidic and neutral conditions, the reaction ran significantly faster. The studied material shows some sorption properties but its sorption capacity is much lower than its oxidation capacity. The treatment, in a column regime, of the arsenic solution containing 1 mg As(III) dm^?3 and coexisting ions in concentrations similar to those in natural waters, confirmed the excellent oxidation capacity of the obtained product. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39489.     

Characterization of equine cDNA sequences for alphaS1-, beta- and kappa-casein

Here we report the entire cDNA sequences for equine alphaS1-, beta- and kappa-casein. Based on interspecies comparison, nine exons were found in equine beta-casein and five in kappa-casein. In equine alphaS1-casein cDNA the exon 5 was missing, which resulted in the total of 18 exons instead of 19 theoretically possible exons in alphaS1-casein cDNA. Comparison of DNA sequences representing exon 5 in other species with corresponding equine genomic region confirmed the presence of cryptic exon in horse genomic DNA. Equine alphaS1-casein mRNA was present in three forms in the lactating mammary gland and we showed that the two shorter forms were produced by skipping either the exon 8 or exon 15. In horse, as in some other mammals, beta- and kappa-casein are considerably more conserved (sequence identity 53% to 59% and 57% to 67%, respectively) than alphaS1-casein which appears as the most variable casein among species (sequence identity 40% to 54%). Interestingly, horse caseins resemble human much more than bovine caseins which may also explain the high dietetic value of mares' milk.     

Females of the Bumblebee Parasite, <Emphasis Type="Italic">Aphomia sociella</Emphasis>, Excite Males Using a Courtship Pheromone

Aphomia sociella (Lepidoptera: Pyralidae: Galleriinae) is a parasitic moth of bumblebees. Behavioral experiments show that A. sociella females emit semiochemicals that influence male pre-mating behavior and serve as a courtship pheromone. GC/EAD and two-dimensional GC/MS (GCxGC-TOFMS) analyses of extracts of females revealed three antennally active compounds. Comparative GC and GCxGC-TOFMS analyses of extracts and synthetic standards confirmed the identity of the antennally active compounds as hexan-1-ol (1), 6,10,14-trimethylpentadecan-2-one (2), and 6,10,14-trimethylpentadecan-2-ol (3). In laboratory bioassays, alcohol 3 and, at higher doses, ketone 2 initiated male courtship behavior associated with ultrasonic production. Hexan-1-ol (1) and ketone 2 enhanced the activity of alcohol 3. These data suggest that hexan-1-ol, 6,10,14-trimethylpentadecan-2-ol, and 6,10,14-trimethylpentadecan-2-one constitute the female-produced courtship pheromone of A. sociella.     

Chemistry and Anatomy of the Frontal Gland in Soldiers of the Sand Termite Psammotermes hybostoma

A great diversity of defensive chemicals has been described in termite soldiers equipped with a unique defensive organ, the frontal gland. Along with the functional diversity of these compounds, reflecting the evolutionary history of particular lineages and their defensive strategies, a considerable degree of chemical variability often occurs among species and populations. Thus, the chemistry of termite defense may provide information on the phylogeny and geographic dispersal of species and populations. In this paper, we report on the anatomy of the frontal gland and on the diversity of soldier defensive chemicals in the sand termite, Psammotermes hybostoma, from nine colonies and five different localities in Egypt. Using gas chromatography-mass spectrometry, a total of 30 sesquiterpene hydrocarbons, or their oxygenated derivatives, were detected, and the chemical identity of most of them identified. In addition, a ketone, an ester, and a diterpene were identified in some colonies. Within colonies, the chemical composition was stable and did not differ among soldier size categories. However, there were pronounced quantitative and qualitative differences in frontal gland chemicals among colonies and geographic locations. The findings are discussed in a broader comparison with other termite taxa.     

A multi-element mapping approach for size-segregated atmospheric particles using laser ablation ICP-MS combined with image analysis

This is a first attempt to measure the elemental mass loading in size-segregated aerosol particles using a laser ablation ICP-MS mapping approach in combination with image analysis software. For optimal mapping of impaction spots on foils the laser ablation ICP-MS parameters resolution, sensitivity and analysis time were critically balanced, depending on the size of the particles and the mass loading. It was shown that size-segregated particles originating from industry-influenced or urban areas could be visualized (shades of gray or “pseudocolours” representing mass loading) and digitally analyzed by comparison with a commercially available air particulate SRM (NIST 2783). Actual results for industry-influenced and urban aerosol particles show distribution profiles that are similar to these obtained with a conventional wet-chemical leaching approach (with ICP-OES or ICP-MS analysis). Also the mass loadings were in the same range although with whole-spot laser ablation ICP-MS analysis even elemental concentrations in nanoparticles could be measured whereas the leaching approach had insufficient sensitivity to measure these particles. Contrary to the use of single line or crater laser ablation ICP-MS as sometimes practiced in the literature it was found essential to map whole impaction spots due to artifacts generated by cascade impactor sampling, leading to distorted impaction spots (presence of halos or satellites).     

Protein incorporation within Ti scaffold for bone ingrowth using Sol-gel SiO<Subscript>2</Subscript> as a slow release carrier

Porous titanium structures hold considerable promise as scaffolds for bone ingrowth in load bearing locations provided they are made osteoinductive by incorporation of bone growth factors. The purpose of the present research was to incorporate soybean trypsin inhibitor (STI) imitating growth factor into a porous Ti scaffold using sol-gel silica as a slow-release protein carrier. Alcohol-free TMOS-based sols (of pH 2 or 5) with dissolved STI were injected into Ti wire scaffolds yielding SiO₂ coating on the wire struts and SiO₂ beads entrapped in-between the wires. The formation of well-polymerized nanoporous SiO₂ was confirmed by FTIR, solid-state NMR, N₂ adsorption/desorption isotherms and BET analysis. In-vitro dissolution of silica and STI release in phosphate buffered saline (PBS) at 37 °C were measured by ICP-AES and Bradford assay, respectively. The biochemical activity of released STI protein was assessed by enzymatic assay. STI release was found to follow an attractive pattern of rapid release during the first 5 days followed by steady slow release for over one month. Despite certain conformational changes induced by the encapsulation procedure (detected by Circular Dichroism), the released STI retained most of its biological activity, especially when silica sol was prepared at the high protein-friendly pH = 5.     

Electrochemical reduction of trinitrotoluene on core-shell tin-carbon electrodes

In this work, we studied the electrochemical process of 2,4,6-trinitrotoluene (TNT) reduction on a new type of electrodes based on a core-shell tin-carbon Sn(C) structure. The Sn(C) composite was prepared from the precursor tetramethyl-tin Sn(CH₃)₄, and the product contained a core of submicron-sized tin particles uniformly enveloped with carbon shells. Cyclic voltammograms of Sn(C) electrodes in aqueous sodium chloride solutions containing TNT show three well-pronounced reduction waves in the potential range of −0.50 to −0.80 V (vs. an Ag/AgCl/Cl⁻ reference electrode) that correspond to the multistep process of TNT reduction. Electrodes containing Sn(C) particles annealed at 800 °C under argon develop higher voltammetric currents of TNT reduction (comparing to the as-prepared tin-carbon material) due to stabilization of the carbon shell. It is suggested that the reduction of TNT on core-shell tin-carbon electrodes is an electrochemically irreversible process. A partial oxidation of the TNT reduction products occurred at around −0.20 V. The electrochemical response of TNT reduction shows that it is not controlled by the diffusion of the active species to/from the electrodes but rather by interfacial charge transfer and possible adsorption phenomena. The tin-carbon electrodes demonstrate significantly stable behavior for TNT reduction in NaCl solutions and provide sufficient reproducibility with no surface fouling through prolonged voltammetric cycling. It is presumed that tin nanoparticles, which constitute the core, are electrochemically inactive towards TNT reduction, but Sn or SnO₂ formed on the electrodes during TNT reduction may participate in this reaction as catalysts or carbon-modifying agents. The nitro-groups of TNT can be reduced irreversibly (via two possible paths) by three six-electron transfers, to 2,4,6-triaminotoluene, as follows from mass-spectrometric studies. The tin-carbon electrodes described herein may serve as amperometric sensors for the detection of trace TNT.