Although cuticular hydrocarbons (CHCs) have received much attention from biologists because of their important role in insect communication, few studies have addressed the chemical ecology of clonal species of eusocial insects. In this study we investigated whether and how differences in CHCs relate to the genetics and reproductive dynamics of the parthenogenetic ant Cerapachys biroi. We collected individuals of different ages and subcastes from several colonies belonging to four clonal lineages, and analyzed their cuticular chemical signature. CHCs varied according to colonies and clonal lineages in two independent data sets, and correlations were found between genetic and chemical distances between colonies. This supports the results of previous research showing that C. biroi workers discriminate between nestmates and non-nestmates, especially when they belong to different clonal lineages. In C. biroi, the production of individuals of a morphological subcaste specialized in reproduction is inversely proportional to colony-level fertility. As chemical signatures usually correlate with fertility and reproductive activity in social Hymenoptera, we asked whether CHCs could function as fertility-signaling primer pheromones determining larval subcaste fate in C. biroi. Interestingly, and contrary to findings for several other ant species, fertility and reproductive activity showed no correlation with chemical signatures, suggesting the absence of fertility related CHCs. This implies that other cues are responsible for subcaste differentiation in this species. 相似文献
In the course of our studies on structured reverse lyotropic liquid crystals (LLC) as oleogels, a system was designed with the desired physical and rheology properties for cosmetic and pharmaceutical applications. The aqueous phase was partially replaced by glycerol to minimize bacteriological problems and obtain specific rheology characteristics. The constructed phase diagrams are based on ternary mixtures of glycerol monooleate (GMO), decane, water, and glycerol. The main lyotropic mesophase obtained in this study was reverse hexagonal derived from dilution line 8:2 (72 wt% GMO and 18 wt% decane) and 10 wt% water; or water:glycerol (wt ratios 3:1 and 1:1) mixture. It was found that heat‐cool fluctuation caused formation of new pseudo‐equilibrium structures with mesomorphic transformations to more fluid and less ordered mesostructures. Replacing up to 50 wt% of the water by glycerol significantly increases the gel phase region in the phase diagram, meaning more structural compositional options. The structural parameters were determined using cross‐polarized light microscopy (CPLM), differential scanning calorimeter (DSC), powder X‐ray diffraction (PXRD), and small angle X‐ray scattering (SAXS). Rheological measurements revealed viscoelastic properties of lyotropic liquid crystals with a decrease in the elasticity (G′), plasticity (G″), and complex viscosity (η*), as a function of increasing the glycerol content. 相似文献
A pressurized melt gyration process has been used for the first time to generate poly(ε‐caprolactone) (PCL) fibers. Gyration speed, working pressure, and melt temperature are varied and these parameters influence the fiber diameter and the temperature enabled changing the surface morphology of the fibers. Two types of nonwoven PCL fiber constructs are prepared. First, Ag‐doped PCL is studied for antibacterial activity using Gram‐negative Escherichia coli and Pseudomonas aeruginosa microorganisms. The melt temperature used to make these constructs significantly influences antibacterial activity. Neat PCL nonwoven scaffolds are also prepared and their potential for application in muscular tissue engineering is studied with myoblast cells. Results show significant cell attachment, growth, and proliferation of cells on the scaffolds.
The electrochemical reduction of some N-acylamino-, N-amino-, N-benzyl- and N-phenacyl-substituted pyridinium and triazolium ions is investigated in acetonitrile by voltammetric methods and potentiostatic electrolyses. The acylaminopyridinium ions 1 and the arylaminopyridinium ions 3 are cathodically cleaved into the pyridine derivative and the carboxylic amide or the aromatic amine. In the case of the 1-benzyl-4-acylaminotriazolium ions 5 the reductive formation of hydrogen from the acidic N-acylamino group is preferred and the corresponding ylide is formed, which reacts at more negative potential by splitting off the benzyl group. The reduction of the N-phenacylpyridinium ion 7d occurs with splitting off the phenacyl radical, which dimerizes to 1,2-dibenzoylethane in a good yield. In the case of N-benzyl- and N-p-cyanobenzylpyridinium ions the cathodic dimerization to the corresponding bisdihydropyridines was found, whereas the electrolysis of the N-nitrobenzylpyridinium ions occurs with cleavage of the N-substituent-bond, which is initiated by the primary formation of the nitrophenyl anion radical. It follows from electrogenerated chemiluminescence experiments that the cleavage of the cations 1 and 5 occurs with the uptake of one electron. 相似文献
Photochemistry of Substituted Cycloheptatrienes. XV. About the Characterization of the Electronic Transitions in 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienes The absorption spectra of the title compounds are discussed in dependence on polarity of the solvent and its ability to form hydrogen bonds. The results suggest a hybridization of the N-atom of the dimethylamino group between sp3 and sp2 in the ground state. Contrary to this, the nitrogen has sp2-hybridization in the short wavelength (SE) fluorescing state. In a second fluorescence state the geometry of the seven-membered ring should change. Therefore the viscosity of the solvents influences both the position and the quantum yield of this long wavelength emission (LE). The influence of polarity and viscosity of the solvents is described by multiple regression. The temperature dependence of fluorescence quantum yields is discussed, as well. 相似文献
Cassava starch has poor paste stability during prolonged cooking. The starch was modified by heat moisture treatment. A premoistured starch (18–24% moisture) was subjected to heat treatment for 3–16h to bring about paste stability. Different types of heat treatments like moist pressure heating, dry heating and microwave heating was tried. The optimum heat treatment to bring about the paste stability was found to be 18–21% premoistured starch, which was heated at 110°C per 16h. The modified starch granules were intact and had comparatively increased sedimentation volume, oil binding capacity, amylase susceptibility, and decreaced crystallinity, water binding capacity, solubility and paste translucency. The freeze - thaw stability was excellent with modified cassava starch. “Pie filling and Halwa” (an Indian sweetmeat) made from modified cassava starch had good organoleptic properites. 相似文献