Ontogenetic, histological, semiochemical and ethological research of Pachyiulus hungaricus (Karsch, 1881) (Diplopoda, Julida, Julidae)

U ovoj tezi predstavljeni su rezultati istraţivanja razliĉitih aspekata biologije diplopode Pachyiulus hungaricus (Karsch, 1881): kasnog perioda postembrionalnog razvića, histološke graĊe odbrambenih ţlezda, sastava i antimikrobnog dejstva odbrambenog sekreta i reproduktivnog ponašanja. Euanamorfno razviće je prouĉavano kroz stadijume VII-XII, odnosno, kroz period kasne postembriogeneze. Definisanje stadijuma izvedeno je na osnovu broja nizova ocela, dok vrednosti analiziranih morfoloških osobina imaju dopunski informacioni znaĉaj. Adultne jedinke sa funkcionalnim gonopodama i funkcionalnim vulvama uoĉene su na stadijumu XI. Histološka graĊa odbrambenih ţlezda je analizirana kod adultnih jedinki. Komponente odbrambenog sekreta su lokalizovane u sekretornim granulama, koje se, na osnovu odreĊenih morfoloških osobina mogu svrstati u nekoliko tipova. Rezultati ultrastrukturne analize ukazuju da se sekret kanalima doprema u lumen rezervoara, što odgovara merokrinom tipu sekrecije. Dominantna jedinjenja u sekretu P. hungaricus su hinoni, dok su nehinonska jedinjenja u vidu pentil i heksil estara zasićenih i nezasićenih masnih kiselina dugog niza. Sekret je ispoljio inhibitorno dejstvo na rast gljiva i bakterija, kao i baktericidno i fungicidno dejstvo. S obzirom da u privlaĉenju partnera mogu da deluju i hemijski stimulusi, prouĉavan je aspekat reproduktivnog ponašanja, prekopulatorno ponašanje. Opisano je nekoliko sekvenci ponašanja u testu nazvanom „arena za parenje“, a zatim u testovima izbora muţjaka i izbora ţenki. Nekoliko morfoloških osobina jedinki koje su se parile i onih koje nisu imale uspeha u parenju, analizirano je metodama tradicionalne i geometrijske morfometrije. Rezultati su pokazali da je osobina oblika nogu podloţna prekopulatornoj seksualnoj selekciji.In this thesis, the results of research on various aspects of biology of diplopod Pachyiulus hungaricus (Karsch, 1881) are presented: late period of postembryonic development, histological structure of defensive glands, composition and antimicrobial effect of defensive secretion and reproductive behaviour. Stadia VII-XII, which belong to the late period of euanamorphic development, were included in the analysis. Counting rows of ocelli was the primary method for differentiating between stadia, while the other analysed morphological traits are of supplementary informational significance. Adults possess functional gonopods and functional vulvae at the stadium XI. Histological structure of defensive glands was investigated in adults. Components of defensive secretion are localized in secretory granules, which could be classified into several types, based on their morphology. Results of ultrastructural analysis indicate that ducts transport the secretion into reservoir lumen, which corresponds to the merocrine secretion mode. Dominant compounds in the secretion of P. hungaricus are quinones, and nonquinonic compounds are pentyl and hexyl esters of long-chain fatty acids. The secretion had inhibitory effect on the growth of tested bacteria and fungi, as well as bactericidal and fungicidal effect. Considering that chemical stimuli could be important in the mate attraction, we studied the aspect of reproductive behaviour, precopulatory behaviour. Several sequences of the behaviour were described during mating arena test and then in male and female choice tests. Also, several morphological traits of mated and nonmated individuals were analysed using traditional and geometric morphometrics. The results indicate that the leg shape is subjected to precopulatory sexual selection

Chemical Defence in a Millipede: Evaluation and Characterization of Antimicrobial Activity of the Defensive Secretion from Pachyiulus hungaricus (Karsch, 1881) (Diplopoda, Julida, Julidae)

The chemical defence of the millipede Pachyiulus hungaricus is reported in the present paper, in which a chemical characterization is given and antimicrobial activity is determined. In total, independently of sex, 44 compounds were identified. All compounds belong to two groups: quinones and pentyl and hexyl esters of long-chain fatty acids. The relative abundances of quinones and non-quinones were 94.7% vs. 5.3% (males) and 87.3% vs. 12.7% (females), respectively. The two dominant quinones in both sexes were 2-methyl-1,4,-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone. Antibacterial and antifungal activity of the defensive secretion was evaluated in vitro against seven bacterial strains and eight fungal species. With the aid of a dilution technique, the antimicrobial potential of the secretion and high sensitivity of all tested strains were confirmed. The lowest minimum concentrations of these compounds (0.20-0.25 mg/mL) were sufficient for inhibition of Aeromonas hydrophila, Listeria monocytogenes and Methicillin resistant Staphylococcus aureus (MRSA). The growth of eight tested fungal species was inhibited by slightly lower concentrations of the secretion, with Fusarium equisetias the most sensitive fungus and Aspergillus flavus as the most resistant. Values of MIC and MFC in the employed microdilution assay ranged from 0.10 to above 0.35 mg/m L. The given extract contains antimicrobial components potentially useful as therapeutic agents in the pharmaceutical and agricultural industries

Ontogenetic, histological, semiochemical and ethological research of Pachyiulus hungaricus (Karsch, 1881) (Diplopoda, Julida, Julidae)

U ovoj tezi predstavljeni su rezultati istraţivanja razliĉitih aspekata biologije diplopode Pachyiulus hungaricus (Karsch, 1881): kasnog perioda postembrionalnog razvića, histološke graĊe odbrambenih ţlezda, sastava i antimikrobnog dejstva odbrambenog sekreta i reproduktivnog ponašanja. Euanamorfno razviće je prouĉavano kroz stadijume VII-XII, odnosno, kroz period kasne postembriogeneze. Definisanje stadijuma izvedeno je na osnovu broja nizova ocela, dok vrednosti analiziranih morfoloških osobina imaju dopunski informacioni znaĉaj. Adultne jedinke sa funkcionalnim gonopodama i funkcionalnim vulvama uoĉene su na stadijumu XI. Histološka graĊa odbrambenih ţlezda je analizirana kod adultnih jedinki. Komponente odbrambenog sekreta su lokalizovane u sekretornim granulama, koje se, na osnovu odreĊenih morfoloških osobina mogu svrstati u nekoliko tipova. Rezultati ultrastrukturne analize ukazuju da se sekret kanalima doprema u lumen rezervoara, što odgovara merokrinom tipu sekrecije. Dominantna jedinjenja u sekretu P. hungaricus su hinoni, dok su nehinonska jedinjenja u vidu pentil i heksil estara zasićenih i nezasićenih masnih kiselina dugog niza. Sekret je ispoljio inhibitorno dejstvo na rast gljiva i bakterija, kao i baktericidno i fungicidno dejstvo. S obzirom da u privlaĉenju partnera mogu da deluju i hemijski stimulusi, prouĉavan je aspekat reproduktivnog ponašanja, prekopulatorno ponašanje. Opisano je nekoliko sekvenci ponašanja u testu nazvanom „arena za parenje“, a zatim u testovima izbora muţjaka i izbora ţenki. Nekoliko morfoloških osobina jedinki koje su se parile i onih koje nisu imale uspeha u parenju, analizirano je metodama tradicionalne i geometrijske morfometrije. Rezultati su pokazali da je osobina oblika nogu podloţna prekopulatornoj seksualnoj selekciji.In this thesis, the results of research on various aspects of biology of diplopod Pachyiulus hungaricus (Karsch, 1881) are presented: late period of postembryonic development, histological structure of defensive glands, composition and antimicrobial effect of defensive secretion and reproductive behaviour. Stadia VII-XII, which belong to the late period of euanamorphic development, were included in the analysis. Counting rows of ocelli was the primary method for differentiating between stadia, while the other analysed morphological traits are of supplementary informational significance. Adults possess functional gonopods and functional vulvae at the stadium XI. Histological structure of defensive glands was investigated in adults. Components of defensive secretion are localized in secretory granules, which could be classified into several types, based on their morphology. Results of ultrastructural analysis indicate that ducts transport the secretion into reservoir lumen, which corresponds to the merocrine secretion mode. Dominant compounds in the secretion of P. hungaricus are quinones, and nonquinonic compounds are pentyl and hexyl esters of long-chain fatty acids. The secretion had inhibitory effect on the growth of tested bacteria and fungi, as well as bactericidal and fungicidal effect. Considering that chemical stimuli could be important in the mate attraction, we studied the aspect of reproductive behaviour, precopulatory behaviour. Several sequences of the behaviour were described during mating arena test and then in male and female choice tests. Also, several morphological traits of mated and nonmated individuals were analysed using traditional and geometric morphometrics. The results indicate that the leg shape is subjected to precopulatory sexual selection

Fly ash as the potential raw mixture component for portland cement clinker synthesis

This paper presents the results of investigation of properties of fly ash from four major thermal power plants in Serbia. Chemical, mineralogical and thermal characterization of fly ash has been performed in order to determine the possibility of its use as the raw material for the construction material industry, primarily the cement industry. Thermal properties of the raw mixtures for Portland cement clinker production based on fly ash were also investigated. The conclusion was reached that the use of fly ash as a component of the raw mixture components for the production of cement clinker not only enables substitution of natural raw materials, but could also have a positive influence on reduction of the sintering temperature of Portland cement clinker

Investigation of fly ash properties with purpose of its utilization as a secondary raw material for portland cement clinker production

In this paper the results of the investigated properties of fly ash from four thermal power plants in Serbia are presented. The physical, chemical, mineralogical and thermal characterization of fly ash was carried out, in order to determine the possibility to utilize this material in the building materials industry, foremost in the cement industry. It was determined that, although there are differences concerning the physical, chemical, and mineralogical characteristics of the investigated samples, they are very similar concerning their thermal characteristics. It was concluded that using fly ash as one of the raw components in the mixture for Portland cement clinker synthesis, not only enables the substitution of natural resources, but it might have a positive effect on the lowering of the sintering temperature

Sexual size and shape dimorphism in Brachydesmus troglobius Daday, 1889 (Diplopoda, Polydesmida)

Volume: 930Start Page: 75-8

Preliminary cytotoxicity testing of newly synthesised SBA-15 material

Material SBA-15 with all of its particles in the form of regular spheres was synthesised by template method using Pluronic P123 (non-ionic triblock copolymer) as a surfactant and tetraethoxysilane (TEOS, 98%) as a source of silica. The synthesis of spherical SBA-15 was carried out in acidic conditions according to method proposed by Zhao et al. Instead of expensive commercial cetyltrimethylammonium bromide as a co-surfactant, a spent HCl solution obtained after the chemical treatment of clay in an aqueous solution of HCl was used. The mixture was aged at a higher temperature. After that, the spherical SBA-15 was made by drying at room temperature after washing with distilled water and then calcining in flowing air to decompose the triblock copolymer. The continual presence of spheres of diameters around 2 μm in the entire SBA-15 was confirmed by scanning electron microscopy. The Energy-dispersive X-ray spectroscopy confirmed that the spheres consisted only of SiO2 in composition. In addition, X-ray diffraction and Fourier-transform infrared spectroscopy methods were used to characterise SBA-15 material. To assess the cytotoxic effects of newly synthesised SBA-15 material, HEK 293 cells were treated with particles and extracts obtained from particles incubated 24 hours at 37 °C in serum-free DMEM medium and DMEM with 10% serum. Cells were treated with concentrations of 100, 250, and 500 µg/mL for 72 hours. All treatments reduced cell viability in a concentration dependent manner (p<0.001). Cytotoxicity was more pronounced in particle treatment, indicating that mechanical damage was induced in cells, whereas the extraction process influences the level of toxicity since the sera-free medium had the mildest effect. To acquire safe particles for human use, additional synthesis optimisation is required

Multifaceted activity of millipede secretions: Antioxidant, antineurodegenerative, and anti-Fusarium effects of the defensive secretions of Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) (Diplopoda: Julida).

Members of the millipede order Julida rely on dominantly quinonic defensive secretions with several minor, non-quinonic components. The free radical-scavenging activities of ethanol, methanol, hexane, and dichloromethane extracts of defensive secretions emitted by Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) were investigated using the ABTS, DPPH, and total reducing power (TRP) tests. The obtained extracts were also tested for inhibition of acetylcholinesterase and tyrosinase activity. Finally, the antifungal potential of both julid extracts was evaluated against seven Fusarium species. Secretions of both species showed activity against free radicals, acetylcholinesterase, tyrosinase, and all of the selected fungal species. The secretions of P. hungaricus exhibited a more potent antioxidative effect than did those of M. unilineatum, while there were no significant differences of antiacetylcholinesterase activity between the tested extracts. Only the hexane extract of M. unilineatum showed an effect on tyrosinase activity stronger than that of P. hungaricus. Fusarium sporotrichioides, F. graminearum, and F. verticillioides were the fungi most resistant to secretions of both julids. The Fusarium species most susceptible to the secretion of P. hungaricus was F. avenaceum, while the concentrations of M. unilienatum extracts needed to inhibit and completely suppress fungal growth were lowest in the case of their action on F. lateritium. Our data support previous findings that julid defensive secretions possess an antimicrobial potential and reveal their antioxidative and antineurodegenrative properties. Bearing in mind the chemical complexity of the tested defensive secretions, we presume that they can also exhibit other biological activities

Hydrogen storage properties of MgH2 mechanically milled with alpha and beta SiC

To understand the influence of various crystallographic phases on hydrogen storage properties, ball milling of MgH2 with hexagonal (alpha) and cubic (beta) SiC have been performed. Structural characterization of all samples has been done by X-ray diffraction (XRD) analysis, particle size analysis and scanning electron microscopy (SEM). Investigation of hydrogen desorption properties of prepared nanocomposites has been done using temperature programmed desorption (TPD) technique. Despite the results of structural and morphological characterization of obtained nanocomposites are very similar, TPD spectra show significant differences regarding existence of intermediate temperature peak. In the sample milled with hexagonal SiC this peak originates both from H-2 and H2O, while in the sample milled with cubic phase it only comes from H2O. Both samples exhibit low temperature H-2 peak at 385 K. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved