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PubMed2004

The relationship between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say).

The chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A. obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A. obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre(-1) air. An attempt to correlate the insecticidal activity to the monoterpenoid's structure is presented, and the difference in sensitivity between male and female individuals is also explored.

Animals↗
PubMed1995

Cellular adaptation to chronic cadmium exposure: intracellular localization of metallothionein protein in human trophoblast cells (JAr).

Trophoblast cells are the first embryonic cells that modulate the transfer of a variety of compounds (oxygen, amino acids, xenobiotics, metals) from the maternal to the fetal circulation in the human placenta. Human placental exposure to the toxic metal, cadmium (Cd) results in a decrease in the production of human chorionic gonadotropin (hCG), a decrease in the maternal to fetal transport of zinc (Zn), and trophoblastic necrosis. Thus, the ability of trophoblast cells to adapt to exposure to the toxic metal Cd has been considered crucial. In this study, the expression and intracellular localization of metallothionein (MT), a small molecular weight, metal binding protein, was examined in trophoblast cells (JAr) grown in normal media and in cells exposed chronically (6 months) to 2 microM CdCl2. Conventional and confocal fluorescence microscopy were used to examine the intracellular localization of MT protein in control cells and cells grown chronically in Cd. In unexposed trophoblast cells, MT protein was primarily perinuclear with low level, punctate expression in the cytosol. Following both chronic and 24 hour exposure to Cd, MT protein levels were increased (at least 3-fold in both chronic and acute exposures) and the protein was now concentrated inside the nucleus with a lacy, cytoskeletal pattern of expression in the cytosol. To determine if the nuclear accumulation of MT protein was dependent on new protein synthesis, control cells were exposed to CdCl2 (2 microM) and cycloheximide (2 micrograms/. ml) for 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadmium↗
PubMed1988

Class separation of mutagenic polycyclic organic material in grilled and smoked foods.

A method for class separation of mutagenic polycyclic organic material in grilled and smoked foods is described. The procedure involves an initial extraction with acetone, removal of fat and proteins by precipitation at -55 degrees C, and an acid-base extraction. Further fractionation was carried out by gel filtration and silica gel chromatography. In four samples of grilled sausages, 80%-90% of the extracted mutagenicity (TA98 + S9) was contained in the basic fractions. Flame-grilled sausages showed higher mutagenicity than charcoal-grilled ones. In a smoked fish sample, the mutagenicity was low and evenly distributed between the basic and the neutral/acidic fractions. A few samples showed a weak direct-acting mutagenicity in the neutral/acidic fractions. The presence of nitrite in grilled sausages did not influence the mutagenicity markedly. Gas chromatography-selected ion monitoring was used to successfully identify a number of polycyclic aromatic hydrocarbons (PAHs) and tentatively identify several nitro-PAHs and oxygenated compounds. However, the identification of mutagens in the basic fractions was complicated by peak tailing and the presence of co-eluting material.

Animals↗
PubMed1992

Photon emission of phagocytes in relation to stress and disease.

Phagocytes, the first-line cells of the body's defence mechanisms against invading pathogens, kill microorganisms by means of lysosomal degradative enzymes and highly toxic reactive oxygen intermediates. The reactive oxygen compounds are produced, in a process called the 'respiratory burst', by the NADPH oxidase complex in plasma membranes, and by myeloperoxidase in phagolysosomes after degranulation. These processes generate electronically excited states which, on relaxation, emit photons, giving rise to phagocyte chemiluminescence (CL). This paper describes the conditions for the measurement of CL, and reviews the activity of phagocytes from individuals undergoing stress or disease. The capability of phagocytes to emit photons reflects remarkably well the pathophysiological state of the host. In many cases even the magnitude of the stress, the presence of a pathogen in the body, or the activity of the disease can be estimated. Physiological changes, e.g. in the reproductive cycle, can also be predicted.

Arthritis↗
PubMedDate not supplied

Etiologic factors and pathologic alterations in selenium-vitamin E deficiency and excess in animals and humans.

The etiology of selenium-vitamin E (Se-E) deficiency diseases may be complex. Many of the syndromes involve combined deficiency of selenium and vitamin E. Selenium moves into the animal and human food chain from soil and plants, which may contain inadequate amounts of the nutrient in many areas of the world. Vitamin E may be in low concentration in many animal feeds unless supplements are added. Some syndromes, such as steatitis in cats, result from an increased requirement of vitamin E in diets that contain large amounts of polyunsaturated fatty acids, and these diseases will only respond to vitamin E administration. Deficiency syndromes in animals owing to pure Se deficiency are infrequent and have been produced mainly by laboratory studies utilizing extreme deficiency conditions. Other factors that may affect the occurrence of these deficiency diseases are concurrent dietary deficiency of S-containing amino acids, bioavailability of different forms of dietary Se, intake of compounds that antagonize Se (e.g., silver salts), and exposure to various prooxidant substances (e.g., iron compounds, oxygen, ozone, and various drugs).

Animals↗
PubMed2002

Antimelanogenic activity of hydrocoumarins in cultured normal human melanocytes by stimulating intracellular glutathione synthesis.

The antimelanogenic activity of six hydrocoumarins and alpha-tocopherol (alpha-Toc) in normal human melanocytes was evaluated in both cell culture systems and cell homogenates. The inhibitory effects of hydrocoumarins depended upon their substituent groups. alpha-Toc and some of the hydrocoumarins inhibited melanogenesis in cultured normal human melanocytes, although they did not influence melanin synthesis in enzyme solution prepared as cell homogenates. In addition, alpha-Toc and the hydrocoumarins stimulated intracellular glutathione (GSH) synthesis. In particular, 7-allyl-6-hydroxy-4,4,5,8-tetramethylhydrocoumarin strongly inhibited melanogenesis and intracellular GSH synthesis in normal human melanocytes, more so than alpha-Toc. Furthermore, hydrocoumarins exhibited higher scavenging and quenching activities against with tert-butyl peroxyl radicals and singlet oxygen species. These results suggest that 7-allyl-6-hydroxy-4,4,5,8-tetramethyl hydrocoumarin would be useful as an antimelanogenic agent for the prevention or improvement of skin pigmentation induced by reactive oxygen compounds and free radicals, and may inhibit melanogenesis, including tyrosinase transfer and melanosome differentiation, by interrupting melanization by increasing the intracellular GSH content.

Antioxidants↗
PubMed2005

Methyl tert-butyl ether and tert-butyl alcohol degradation by Fusarium solani.

Fusarium solani degraded methyl tert-butyl ether (MTBE) and other oxygenated compounds from gasoline including tert-butyl alcohol (TBA). The maximum degradation rate of MTBE was 16 mg protein h and 46 mg/g protein h for TBA. The culture transformed 77% of the total carbon to 14CO2. The estimated yield for MTBE was 0.18 g dry wt/g MTBE.

Biodegradation, Environmental↗
PubMed2005

Mandibular gland secretion of Melipona beecheii: chemistry and behavior.

The mandibular gland secretion of Melipona beecheii contains a rich mixture of terpenoid and oxygenated compounds and unsaturated and saturated hydrocarbons. However, it differs markedly from the 11 other Brazilian species examined in previous studies, both by the absence of 2-heptanol and the presence of rose oxides. The most abundant compound was geranyl hexanoate, whereas the most volatile compounds were cis- and trans-rose oxide and geraniol. The complete blend and five individual components found in the gland secretion were tested by electroantennography (EAG) and behavioral assays. The complete mandibular gland extract and geraniol elicited the strongest EAG responses, whereas these and farnesyl acetate induced the strongest attack response from workers. The role of the rose oxides remains to be elucidated, as they do not appear to play a major role as an alarm pheromone of this species.

Animal Communication↗
PubMed2006

The mandibular gland secretions of the leaf-cutting ants Atta sexdens sexdens and Atta opaciceps exhibit intercaste and intercolony variations.

The mandibular gland secretions of worker castes from wild colonies of the leaf-cutting ants Atta sexdens sexdens and Atta opaciceps were analyzed quantitatively by gas chromatography-mass spectrometry. The secretions comprised a complex mixture of volatile, mainly oxygenated compounds, and their profiles exhibited considerable qualitative and quantitative variations among species and castes. The known alarm pheromone 4-methyl-3-heptanone was common to both species. The elevated relative proportions of this ketone found in the secretions of gardeners and generalists suggest that such castes are primarily responsible for the production and release of the alarm pheromone. Quantitative variations (but no qualitative differences) in the profiles of secretions of soldiers from different colonies of A. sexdens sexdens were detected, supporting the view that intraspecific colony recognition is mediated through mandibular gland secretions. Subsequent laboratory assays showed that, among the compounds identified by GC-MS, 4-methyl-3-heptanone elicited a strong alarm response in workers of A. sexdens sexdens and A. opaciceps.

Animals↗
PubMed1990

Synthesis of sweet-tasting methylthio derivatives of D-fructose and sucrose.

1,6-Di-S-methyl-1,6-dithio-D-fructofuranose and its bis(S-oxide) and bis(S,S-dioxide) are described. On examination for sweetness, the oxygenated compounds were neutral but the parent compound was 15-20 times sweeter than sucrose, and 1',6'-di-S-methyl-1',6'-dithiosucrose was slightly less sweet than sucrose.

Carbohydrate Sequence↗
PubMed1986

A priori predictions of the rotational constants for protonated formaldehyde and protonated methanol.

Protonated formaldehyde and protonated methanol are candidate interstellar molecules and models for classes of protonated oxygen compounds. Ab initio molecular orbital theory has been used to compute rotational constants to guide spectroscopic searches both in the laboratory and in space. The ab initio results are empirically corrected to account for systematic deficiencies in the theory and zero-point vibrational effects; they are expected to be accurate to approximately +/-2%. For H2COH+ the resultant constants are (in GHz) A = 194.3, B = 34.28, and C = 29.14; for H3COH2+ A = 103.7, B = 21.18, and C = 20.30.

Astronomical Phenomena↗
PubMed1994

Rapid identification of some coumarin derivatives in deterpenated citrus peel oil by gas chromatography.

Generally on the gas chromatogram of a volatile essential oil, terpenes, oxygenated compounds and sesquiterpenes appear. With temperature programming, it was shown that some non-volatiles are present with the volatiles. They are simple coumarin (2H-1-benzopyran-2-one) derivatives such as citropten (5,7-dimethoxycoumarin) and furocoumarins (psoralen, 7H-furo[3,2-g][1]benzopyran-7-one) such as bergapten (5-methoxypsoralen), some of which are phototoxic. Terpeneless oils are used in perfumes and cosmetics, so it is important to be able to establish rapidly if they contain phototoxic compounds.

5-Methoxypsoralen↗
PubMed1993

Mutagenic peroxides in diethyl ether.

Concentration of water-saturated commercial samples of diethyl ether by a stream of nitrogen yielded an aqueous residue mutagenic in S. typhimurium strains TA100 and TA102, but not TA1535. Reverse phase high-performance liquid chromatography resolved the mixture into 4 UV absorbing peaks, each of which was positive for peroxide and mutagenic in strain TA100 and TA102. One of these was identified as H2O2 based on HPLC retention time and sensitivity to decomposition by catalase, and another as 1-ethoxyethylhydroperoxide, based on its 1H-NMR spectrum. The mutagenic peroxides appeared to be stable in water between pH 3 and 6, but unstable above pH 7; they were less stable in methanol, acetonitrile, and least stable in chloroform, in which they partially decomposed after 24 h at 20 degrees C. Generalization of the results suggests that adverse effects observed in vitro and in vivo with chemicals containing ether linkages that actually have been caused by contaminant peroxides and reactive oxygen compounds.

Chromatography, High Pressure Liquid↗
PubMed1983

A laboratory model for interstellar chemical evolution.

The chemistry in a supersonic plasma source flow was studied as a laboratory model for interstellar chemical evolution. It is important to match the similarity parameters for cosmic and laboratory conditions, which connect the temporal and spatial scales of the two cases. The apparatus simulated the conditions in a molecular cloud with respect to molecular-ionic reaction fraction, temperature, and non-equilibrium kinetics. The plasma flow was found to be cold enough, by the radical expansion, to produce polyatomic molecules. From the simple atomic plasma as reactant, cyanopolyyne and unsaturated hydrocarbons were synthesized in the present experiment. These molecules are also inherent in molecular clouds. The reaction mechanism is discussed.

Computer Simulation↗
PubMed1986

Cellular (thrombocytes, granulocytes) effects of proteinase inhibitors--gabexylate, gabexate mesilate (FOY) and aprotinin.

Because of the involvement of proteinases in the activation mechanism of thrombocytes and granulocytes, the effect of proteinase inhibitors was tested. To document cell activation we used thrombocyte and granulocyte aggregation. Chemiluminescence and superoxide production were used as parameters for the release of activated oxygen compounds, and lysozyme as a marker of lysosomal enzyme release. FOY and aprotinin inhibited all but not arachidonic acid thrombocyte aggregation. Only aprotinin diminished granulocyte responses to various stimuli, while FOY was without effect at concentration less than 100 microM.

Aprotinin↗
PubMed1996

Glutathione plays a role in the chick intestinal calcium absorption.

DL-buthionine-S,R-sulfoximine (BSO) administration to vitamin D-deficient chicks treated with cholecalciferol produces a rapid decrease in the Ca2+ transfer from lumen-to-plasma and in the intestinal glutathione content. This response was reversed by addition of glutathione monoester to the intestinal sac. Variables related to the Ca2+ homeostasis such as plasma Ca and P, and intestinal calbindin D28k were not modified by BSO given to vitamin D-deficient chicks treated with cholecalciferol. Intestinal alkaline phosphatase activity, on the contrary, was highly reduced by BSO in vitamin D-deficient chicks treated with vitamin D3. This effect showed time and dose-dependency. Although the mechanism/s of action of BSO on the intestinal Ca absorption is unknown, it is quite possible that thiol groups of protein involved in the Ca2+ transport are affected by the GSH depletion and/or by block of the antioxidant ability of vitamin D3. Thus, reactive oxygen compounds would be increased and, therefore, the Ca2+ movement from lumen to plasma decreases.

Alkaline Phosphatase↗
PubMed1989

Oxidative damage in the guinea pig hippocampal slice.

Free radicals and active oxygen compounds are implicated in brain ischemia and head trauma. Previous studies have shown that free radicals, generated by radiation and through the Fenton reaction, produce both synaptic and postsynaptic damage in the hippocampal brain slice. To evaluate the contribution of oxidation to the observed damage, the actions of the oxidants, chloramine-T and N-chlorosuccinimide (NCS), were studied on electrophysiological responses in the hippocampal slice isolated from the brains of guinea pigs. Electrical stimulation of afferents to neurons of the CA1 region of hippocampus evoked a population postsynaptic potential (population PSP) in the dendritic layer and a population spike in the cell body layer. Chloramine-T (25-500 microM) and NCS (750-4000 microM) decreased the population spike in a dose-dependent manner (ED50 congruent to 125 microM and 1100 microM, respectively). Input/output curves revealed that both the population PSP were significantly reduced with both oxidants; but, the ability of the population PSP to produce a population spike was not impaired. These studies suggest that oxidation reactions can account for the synaptic component of the damage produced by free radicals but can not account for the postsynaptic effects.

Animals↗
PubMed1992

The sexually differentiated metabolism of [6,7-3H]17 beta-oestradiol in rats: male-specific 15 alpha- and male-selective 16 alpha-hydroxylation and female-selective catechol formation.

The oxygenated-metabolite profiles of exogenous 17 beta-oestradiol (E2) in adult male and female Wistar rats have been characterized and major sex-dependent biotransformations observed which correlate with the regioselectivities of known sexually differentiated hepatic P450. [6,7-3H]E2 (27 micrograms/kg) was given i.v. The metabolites of E2 were rapidly and extensively excreted in bile (46 and 78% of the dose over 1 and 6 h, respectively). Female rats metabolized E2 by one major pathway: oxidation to oestrone (E1) followed by C-2 hydroxylation and O-methylation; the principal aglycones (0-1 h bile collections) were E1 (14%), 2-hydroxyE1 (2-OHE1) (42%) and 2-methoxyE1 (24%). Male rats metabolized E2 principally by two parallel composite pathways of E1 hydroxylation which yielded a complex mixture of mono- and di-oxygenated compounds: 15 alpha-OHE1 (33%), 2,15 alpha-diOHE1 (7%), and 2-methoxy-15 alpha OHE1 (14%); 16 alpha-OHE1 (13%), 2,16 alpha-diOHE1 (4%) and 2-methoxy-16 alpha-OHE1 (2%). 15 alpha-Hydroxylation was unique to males. The balance of aromatic and alkyl hydroxylation in males was dose-dependent: at 3 mg/kg, 15 alpha-hydroxylation was decreased approx. 50% in favour of 2-hydroxylation whilst 16 alpha-hydroxylation was largely unaffected. The male-specific 15 alpha-hydroxylation and male-predominant 16 alpha-hydroxylation of E1 derived from E2 in vivo may be ascribable to the male-specific isoforms P450IIC13 and P450IIC11, respectively.

Animals↗