Population structure of a parasitic plant and its perennial host. (1/27)

Characterization of host and parasite population genetic structure and estimation of gene flow among populations are essential for the understanding of parasite local adaptation and coevolutionary interactions between hosts and parasites. We examined two aspects of population structure in a parasitic plant, the greater dodder (Cuscuta europaea) and its host plant, the stinging nettle (Urtica dioica), using allozyme data from 12 host and eight parasite populations. First, we examined whether hosts exposed to parasitism in the past contain higher levels of genetic variation. Second, we examined whether host and parasite populations differ in terms of population structure and if their population structures are correlated. There was no evidence that host populations differed in terms of gene diversity or heterozygosity according to their history of parasitism. Host populations were genetically more differentiated (F(ST) = 0.032) than parasite populations (F(ST) = 0.009). Based on these F(ST) values, gene flow was high for both host and parasite. Such high levels of gene flow could counteract selection for local adaptation of the parasite. We found no significant correlation between geographic and genetic distance (estimated as pairwise F(ST)), either for the host or for the parasite. Furthermore, host and parasite genetic distance matrices were uncorrelated, suggesting that sites with genetically similar host populations are unlikely to have genetically similar parasite populations.  (+info)

Antioxidant properties of some medicinal plants: Prangos ferulacea (Apiaceae), Sedum sempervivoides (Crassulaceae), Malva neglecta (Malvaceae), Cruciata taurica (Rubiaceae), Rosa pimpinellifolia (Rosaceae), Galium verum subsp. verum (Rubiaceae), Urtica dioica (Urticaceae). (2/27)

Antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, reducing powers and the amount of total phenolic compounds of aqueous and/or methanolic extracts of some medicinal plants used in Eastern Turkey were studied. These plants are Prangos ferulacea (CASIR), Sedum sempervivoides (HOROZ LELESI), Malva neglecta (EBEMGUMECI), Cruciata taurica (SARILIK OTU), Rosa pimpinellifolia (KOYUN GOZU), Galium verum subsp. verum (MADAVUR OTU), Urtica dioica (ISIRGAN). The highest peroxidation inhibitions were shown by aqueous extracts of C. taurica and R. pimpinellifolia (IC(50): 0.00022 mg/l and IC(50): 23 mg/l, respectively). However, the highest DPPH radical scavenging activity, reducing power and the amount of phenolic compounds were shown by R. pimpinellifolia. The lowest antioxidant properties were shown by aqueous extract of M. neglecta.  (+info)

Aqueous extract of Urtica dioica makes significant inhibition on adenosine deaminase activity in prostate tissue from patients with prostate cancer. (3/27)

AIM: Investigation of possible effects of aqueous extract of Urtica dioica leaves on adenosine deaminase activity in prostate tissue from patients with prostate cancer. METHODS: Ten prostate tissues from patients with pathologically proven localized prostate cancer (Gleason scores 4 to 7) were used in the study. In the tissues, ADA activities with and without preincubation with different amounts of Urtica dioica extracts were performed. RESULTS: Aqueous extract of Urtica dioica results in significant inhibition on adenosine deaminase (ADA) activity of prostate tissue. CONCLUSION: ADA inhibition by Urtica dioica extract might be one of the mechanisms in the observed beneficial effect of Urtica dioica in prostate cancer.  (+info)

The role of urtica dioica (urticaceae) in the prevention of oxidative stress caused by tourniquet application in rats. (4/27)

Tourniquets are used in extremity surgery and provide a relatively bloodless field, thereby minimizing blood loss and helping identify the vital structures. However, they may cause an ischemia-reperfusion injury with potentially harmful local and systemic consequences. Many therapeutic effects such as diuretic, natriuretic, hypotensive, anti-rheumatic, anti-prostatic, and in-vitro anti-oxidant effects of the Urtica dioica (UD) have been determined. In the present study, we aimed to investigate the potential role of UD plant for prevention of oxidative stress in muscle tissues generated by tourniquet application in rats. Wistar rats were used in this study. The UD extract or 1.15% KCl aqueous solution, in which UD leaf samples were homogenized, was given to each group of eight rats once a day for 5 days through an intraesophageal canule. No treatment was applied to untreated group. Tourniquets were applied to the left posterior limb of rats for 1 or 2 h followed by a reperfusion period of 1 h. After the ischemia and reperfusion, the rats were killed with a high dose of anesthetic drug, and malonyldialdehyde (MDA) levels were measured in their tibialis anterior muscles. Basal MDA levels were obtained from tibialis anterior muscles of 8 control rats, which were not exposed to ischemia. MDA levels were lower in the UD-treated rats than those in untreated and KCl-treated rats after either 1 or 2 h of ischemia and 1 h reperfusion. These results indicate that UD has a potential antioxidant effect on ischemic muscle tissues.  (+info)

Carbohydrate-binding agents cause deletions of highly conserved glycosylation sites in HIV GP120: a new therapeutic concept to hit the achilles heel of HIV. (5/27)

Mannose-binding proteins derived from several plants (i.e. Hippeastrum hybrid and Galanthus nivalis agglutinin) or prokaryotes (i.e. cyanovirin-N) inhibit human immunodeficiency virus (HIV) replication and select for drug-resistant viruses that show profound deletion of N-glycosylation sites in the GP120 envelope (Balzarini, J., Van Laethem, K., Hatse, S., Vermeire, K., De Clercq, E., Peumans, W., Van Damme, E., Vandamme, A.-M., Bolmstedt, A., and Schols, D. (2004) J. Virol. 78, 10617-10627; Balzarini, J., Van Laethem, K., Hatse, S., Froeyen, M., Van Damme, E., Bolmstedt, A., Peumans, W., De Clercq, E., and Schols, D. (2005) Mol. Pharmacol. 67, 1556-1565). Here we demonstrated that the N-acetylglucosamine-binding protein from Urtica dioica (UDA) prevents HIV entry and eventually selects for viruses in which conserved N-glycosylation sites in GP120 were deleted. In contrast to the mannose-binding proteins, which have a 50-100-fold decreased antiviral activity against the UDA-exposed mutant viruses, UDA has decreased anti-HIV activity to a very limited extent, even against those mutant virus strains that lack at least 9 of 22 ( approximately 40%) glycosylation sites in their GP120 envelope. Therefore, UDA represents the prototype of a new conceptual class of carbohydrate-binding agents with an unusually specific and targeted drug resistance profile. It forces HIV to escape drug pressure by deleting the indispensable glycans on its GP120, thereby obligatorily exposing previously hidden immunogenic epitopes on its envelope.  (+info)

Sugar-binding proteins potently inhibit dendritic cell human immunodeficiency virus type 1 (HIV-1) infection and dendritic-cell-directed HIV-1 transfer. (6/27)

Both endocytic uptake and viral fusion can lead to human immunodeficiency virus type 1 (HIV-1) transfer to CD4+ lymphocytes, either through directional regurgitation (infectious transfer in trans [I-IT]) or through de novo viral production in dendritic cells (DCs) resulting in a second-phase transfer to CD4+ lymphocytes (infectious second-phase transfer [I-SPT]). We have evaluated in immature monocyte-derived DCs both pathways of transfer with regard to their susceptibilities to being blocked by potential microbicidal compounds, including cyanovirin (CNV); the plant lectins Hippeastrum hybrid agglutinin, Galanthus nivalis agglutinin, Urtica dioica agglutinin, and Cymbidium hybrid agglutinin; and the glycan mannan. I-IT was a relatively inefficient means of viral transfer compared to I-SPT at both high and low levels of the viral inoculum. CNV was able to completely block I-IT at 15 microg/ml. All other compounds except mannan could inhibit I-IT by at least 90% when used at doses of 15 microg/ml. In contrast, efficient inhibition of I-SPT was remarkably harder to achieve, as 50% effective concentration levels for plant lectins and CNV to suppress this mode of HIV-1 transfer increased significantly. Thus, our findings indicate that I-SPT may be more elusive to targeting by antiviral drugs and stress the need for drugs affecting the pronounced inhibition of the infection of DCs by HIV-1.  (+info)

Hepatoprotective effects of Nigella sativa L and Urtica dioica L on lipid peroxidation, antioxidant enzyme systems and liver enzymes in carbon tetrachloride-treated rats. (7/27)

AIM: To investigate the effects of Nigella sativa L (NS) and Urtica dioica L (UD) on lipid peroxidation, antioxidant enzyme systems and liver enzymes in CCl(4)-treated rats. METHODS: Fifty-six healthy male Wistar albino rats were used in this study. The rats were randomly allotted into one of the four experimental groups: A (CCl(4)-only treated), B (CCl(4)+UD treated), C (CCl(4)+NS treated) and D (CCl(4)+UD+NS treated), each containing 14 animals. All groups received CCl(4) (0.8 mL/kg of body weight, sc, twice a week for 60 d). In addition, B, C and D groups also received daily i.p. injections of 0.2 mL/kg NS or/and 2 mL/kg UD oils for 60 d. Group A, on the other hand, received only 2 mL/kg normal saline solution for 60 d. Blood samples for the biochemical analysis were taken by cardiac puncture from randomly chosen-seven rats in each treatment group at beginning and on the 60th d of the experiment. RESULTS: The CCl(4) treatment for 60 d increased the lipid peroxidation and liver enzymes, and also decreased the antioxidant enzyme levels. NS or UD treatment (alone or combination) for 60 d decreased the elevated lipid peroxidation and liver enzyme levels and also increased the reduced antioxidant enzyme levels. The weight of rats decreased in group A, and increased in groups B, C and D. CONCLUSION: NS and UD decrease the lipid per-oxidation and liver enzymes, and increase the anti-oxidant defense system activity in the CCl4-treated rats.  (+info)

Spatial distribution of Aglais urticae (L.) and its host plant Urtica dioica (L.) in an agricultural landscape: implications for Bt maize risk assessment and post-market monitoring. (8/27)

Over the past decades, genes of Bacillus thuringiensis var. kurstaki (Berliner) (Bt) coding for protein toxins have been engineered into maize for protection against the European Corn Borer (Ostrinia nubilalis (Hbn.)). However, these transgenic plants may have an impact on non-target organisms. In particular, a potential hazard was identified for non-target lepidopteran larvae, if they consume Bt maize pollen on their host plants. Risk can be defined as a function of the effect of an event (hazard) and the likelihood of this event occurring. Although data on toxicity (hazard) are available from many lab and field studies, knowledge about the environmental exposure of European lepidopteran larvae is incomplete at the population level. Therefore we studied the distribution of small tortoiseshell caterpillars (Aglais urticae (L.)) and its host plant in an agricultural landscape in Germany, to estimate the potential population exposure to maize pollen. The results showed that larvae of the small tortoiseshell developed primarily on freshly sprouted nettle stands (Urtica dioica (L.)) in field margins, rather than adjacent to hedges and groves. However, the main distribution was at margins of cereal (non-maize) fields, where 70% of all larvae were found. This may be due the fact that cereals covered 54% of the survey area, while maize only covered 6.1%. On the other hand, maize fields seem so show higher food plant densities than cereal crops. The results must be interpreted carefully, as the data basis of the present study is very small, and the situation can vary between years due to crop rotation or other changes in agricultural practices. Therefore it is still questionable whether the small tortoiseshell is significantly exposed to maize pollen. For a conclusive risk assessment, more replications and surveys of larger areas in different intensively managed agricultural landscapes over several years are needed.  (+info)

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