Volatile organic compounds as signals in a plant-herbivore system: electrophysiological responses in olfactory sensilla of the moth Cactoblastis cactorum

The morphological sensillum types on the antennae of male and female Cactoblastis cactorum were visualized by scanning electron microscopy. Electrophysiological recordings were performed for the first time on single olfactory sensilla of C. cactorum. The male sensilla trichodea house a receptor cell responding to the putative pheromone component (9Z,12E)-tetradecadienyl acetate. The sensilla trichodea of the females were much shorter than those of the males and contained specialized receptor cells responding to certain terpenoids, the most frequent being the nerolidol-sensitive cell. The sensilla auricillica and sensilla basiconica of both sexes contained cells responding less specifically to terpenoid compounds as well as to green leaf volatiles. Cells of the sensilla coeloconica responded to aliphatic aldehydes and acids. Eight volatile organic compounds emitted by Opuntia stricta, a host plant of C. cactorum, were identified using gas chromatography-mass spectrometry, beta-caryophyllene being the major compound. Five compounds identified by gas chromatography in the headspace of O. stricta elicited responses in olfactory receptor cells of C. cactorum, nonanal being the most active compound and therefore a candidate attractant of C. cactorum.     

Protective properties of artichoke (Cynara scolymus) against oxidative stress induced in cultured endothelial cells and monocytes

It is currently believed that oxidative stress and inflammation play a significant role in atherogenesis. Artichoke extract exhibits hypolipemic properties and contains numerous active substances with antioxidant properties in vitro. We have studied the influence of aqueous and ethanolic extracts from artichoke on intracellular oxidative stress stimulated by inflammatory mediators (TNFalpha and LPS) and ox-LDL in endothelial cells and monocytes. Oxidative stress which reflects the intracellular production of reactive oxygen species (ROS) was followed by measuring the oxidation of 2', 7'-dichlorofluorescin (DCFH) to 2', 7'-dichlorofluorescein (DCF). Agueous and ethanolic extracts from artichoke were found to inhibit basal and stimulated ROS production in endothelial cells and monocytes in dose dependent manner. In endothelial cells, the ethanolic extract (50 microg/ml) reduced ox-LDL-induced intracellular ROS production by 60% (p<0,001) while aqueous extract (50 microg/ml) by 43% (p<0,01). The ethanolic extract (50 microg/ml) reduced ox-LDL-induced intracellular ROS production in monocytes by 76% (p<0,01). Effective concentrations (25-100 microg/ml) were well below the cytotoxic levels of the extracts which started at 1 mg/ml as assessed by LDH leakage and trypan blue exclusion. Penetration of some active substances into the cells was necessary for inhibition to take place as juged from the effect of preincubation time. These results demonstrate that artichoke extracts have marked protective properties against oxidative stress induced by inflammatory mediators and ox-LDL in cultured endothelial cells and monocytes.     

DNA-adducts and atherosclerosis: a study of accidental and sudden death males in the Czech Republic

Atherosclerosis and carcinogenesis may share some common mechanisms of the genotoxic action of exogenous compounds, such as polycyclic aromatic hydrocarbons (PAHs). The main objective of this study was to test the hypothesis that "bulky" aromatic DNA-adducts in smooth muscle cells (SMCs) of thoracic aortas taken at autopsy from sudden and accidental death male subjects, aged between 30 and 60 years (N=133), are associated with the stage of atherosclerosis. The subjects with severe atherosclerotic damage were treated as "Cases" (N=66). The subjects meeting diagnostic criteria for slight and moderate total atherosclerotic body damage were treated as "Controls" (N=67). An additional objective of the study was to evaluate the effect of known atherogenic risk factors and possible modifiers of atherosclerotic changes, such as age, smoking, plasma lipid and antioxidant vitamin levels and some genetic susceptibility markers, e.g. polymorphisms of GSTM1, GSTT1, NAT2, CYP1A1 or apolipoprotein E (APO E) genes. We found significantly higher DNA-adduct levels in "Cases" as compared with "Controls" (2.11+/-1.07 adducts/10(8) nucleotides versus 1.49+/-0.55 adducts/10(8) nucleotides, P<0.001). "Cases" were significantly older and had elevated heart weight and plasma cholesterol levels and a higher frequency of overweight subjects as compared with "Controls". No significant differences in DNA-adduct levels between smokers and non-smokers within either group were detected. Multivariate logistic regression revealed that the "bulky" aromatic DNA-adducts, which are the most likely related to environmental exposure to genotoxic chemicals, remain a statistically significant predictor of the stage of atherosclerosis (OR=3.76, 95% CI=1.54-9.18, P=0.004) even after adjustment for age, smoking, obesity, heart weight and genetic susceptibility markers (GSTT1 and CYP1A1-MspI polymorphisms) that were also significant predictors. The fact that the "bulky" aromatic DNA-adduct levels predict the progression of atherosclerosis independently of smoking indicates that the formation of atherosclerotic plaques may also be initiated by environmental exposures other than tobacco smoke.     

Acrylonitrile exposure: the effect on p53 and p21(WAF1) protein levels in the blood plasma of occupationally exposed workers and in vitro in human diploid lung fibroblasts

Acrylonitrile (ACN) is a compound widely used in the synthesis of a variety of organic products. It has been found that ACN is carcinogenic in rats, and some epidemiological studies also suggest a possible carcinogenic effect of ACN in humans. The aim of the present study was to assess the effect of ACN exposure on the expression of p53 and p21(WAF1) proteins in vitro as well as in vivo. In vitro ACN exposure of human lung fibroblasts resulted in the induction of both p53 and p21(WAF1) proteins. To evaluate the effect of ACN on the levels of p53 and p21(WAF1) proteins in the blood plasma of ACN-exposed workers, samples from 49 subjects (average age 44 years, 88% males, 12% females) exposed to ACN in the petrochemical industry (ACN concentration ranged from 0.05 to 0.3mg/m(3)) were analyzed. Subjects living in the same area (N=24, average age 43 years, 92% males, 8% females), but not working in the petrochemical industry were used as controls. No significant differences in either p53, or p21(WAF1) levels between the exposed and control groups were found. The expression of p53 was significantly higher in exposed non-smokers as compared with smokers (P=0.02). No effect of GSTM1 and GSTT1 genotypes on the expression of either protein was observed. Subjects with an EPHX high activity genotype had significantly higher p21(WAF1) expression as compared with genotypes with low or medium EPHX activity. We conclude that plasma levels of both proteins are not relevant biomarkers for occupational ACN exposure.     

Isolation and characterization of Saccharomyces cerevisiae mutants with a different degree of resistance to killer toxins K1 and K2

Killer toxin K1 of Saccharomyces cerevisiae kills sensitive cells of the same species by disturbing the ion gradient across the plasma membrane after binding to the receptor at cell wall beta-1,6-glucan. Killer protein K2 is assumed to act by a similar mechanism. To identify the putative plasma membrane receptors for both toxins we mutagenized three sensitive S. cerevisiae strains and searched for clones with killer-resistant spheroplasts. The well diffusion assay identified three phenotypically different groups of clones: clones resistant simultaneously to both toxins, clones with lowered sensitivity to only K1 toxin and those with strongly lowered sensitivity to K2 and partially lowered sensitivity to K1 toxin. These phenotypes are controlled by recessive mutations that belong to at least four different complementation groups. This indicates certain differences at the level of interaction of K1 and K2 toxin with sensitive cells.     

Prevalence of URAT1 allelic variants in the Roma population

ABSTRACT

The Roma represents a transnational ethnic group, with a current European population of 8–10 million. The evolutionary process that had the greatest impact on the gene pool of the Roma population is called the founder effect. Renal hypouricemia (RHUC) is a rare heterogenous inherited disorder characterized by impaired renal urate reabsorption. The affected individuals are predisposed to recurrent episodes of exercise-induced nonmyoglobinuric acute kidney injury and nephrolithiasis. To date, more than 150 patients with a loss-of-function mutation for the SLC22A12 (URAT1) gene have been found, most of whom are Asians. However, RHUC 1 patients have been described in a variety of ethnic groups (e.g., Arab Israelis, Iraqi Jews, Caucasians, and Roma) and in geographically noncontiguous countries. This study confirms our previous findings regarding the high frequency of SLC22A12 variants observed. Frequencies of the c.1245_1253del and c.1400C>T variants were found to be 1.92% and 5.56%, respectively, in a subgroup of the Roma population from five regions in three countries: Slovakia, Czech Republic, and Spain. Our findings suggested that the common dysfunction allelic variants of URAT1 exist in the general Roma population and thus renal hypouricemia should be kept in differential diagnostic algorithm on Roma patients with defect in renal tubular urate transport. This leads to confirm that the genetic drift in the Roma have increased the prevalence of hereditary disorders caused by very rare variants in major population.     

A large DNA repeat of the dispersion pattern common to wheat and rye genomes

A Hind III-generated fragment of wheat embryo nuclear DNA has been cloned and sequenced. The cloned fragment corresponds to a 1241 bp long, moderately repeated (60 000 copies/genome) segment of the genomic DNA. The repeat is AT-rich (67%), contains an open reading frame for 151 amino acids and several nucleotide blocks resembling the consensus domain of autonomously replicating sequences. Southern blot hybridization analyses indicate that the repeat is scattered through the wheat genome. A sequence homologous to this repeat occurs also in rye embryo nuclear DNA where it shows the same dispersion pattern as that observed for the wheat repeat.     

Growth of Bacteriophage φ105 and Its Deoxyribonucleic Acid in Radiation-Sensitive Mutants of Bacillus subtilis

Growth of phage phi105 and its deoxyribonucleic acid (DNA) was studied in radiation-sensitive mutants of Bacillus subtilis. The recA gene is required for optimal prophage induction with mitomycin C and for infectivity of prophage DNA. rec B gene is required for marker rescue from mature DNA. The importance of bacterial genes for phage DNA activity seems to depend on phage DNA structure.     

The effect of cytokinin- and auxin-like substances on the anatomy and ultrastructure of vascular bundles in wheat

6-benzylaminopurine (BAP), β-indolylbutyric acid (IBA), phenylacetic acid (PAA) and a triazine herbicide (TH) affected the development of vascular bundles both in coleoptiles and the last intemodium below the ear of wheat plants. These substances were applied before the conductive tissues in the organs investigated were fully differentiated, the degree of their effect being dependent not only on the concentration, but also on the developmental stage of the plants and on cultivation conditions. In coleoptiles the area of vascular bundles was increased especially in the dark. In the stalk, BAP, PAA, IBA and IBA + TH increased the area of phloem. BAP also stimulated the activity of parenchymatous cells of xylem. TH had the same effect only on xylem, which became evident by an increase in vascular bundle area, but not in that of phloem. These anatomical aberrations were confirmed by cytological analysis which revealed that the stimulatory effect of the substances investigated consisted in activation both of companion cells of phloem and parenchymatous cells of xylem, whose function is analogous. As a result, both types of cells contained numerous organelles characteristic of meristematic cells, which suggests protein synthesis and an active transport of substances.