Isolating barriers between interbreeding sympatric or parapatric interfertile species are maintained by processes that occur within their hybrid zones. Although the effects of intrinsic selection on hybrid fitness are well known, less is understood about extrinsic fitness variation. At Tiryal Dag, northeast Turkey, Rhododendron x sochadzeae (R. ponticum x caucasicum) forms large populations in which neither segregation nor backcrossing occur, in habitats intermediate between those of its parents. Using single-copy species-specific random amplified polymorphic DNA and inter simple sequence repeat markers, it was determined that most or all R. x sochadzeae plants are F1s, and that there are many separate genets present. Hand pollination and germination experiments showed that R. x sochadzeae plants can produce viable seed of F2s or backcrosses in either direction. Furthermore, adult backcrosses have been observed in habitats atypical for R. x sochadzeae. From this, all non-F1 hybrid derivatives appear to be eliminated in the hybrid zone at Tiryal Dag as a result of postgermination selection. This absence of post-F1 hybrid derivatives apparently prevents introgression. This type of hybrid population is here termed an F1-dominated hybrid zone (F1DZ), and also occurs in Encelia. The observed dominance of F1s within a narrow habitat range is best explained by habitat-mediated superiority of F1s over all other genotype classes. Therefore, habitat-mediated selection against the second hybrid generation might be preventing interspecific gene flow in R. x sochadzeae. F1DZ formation is postulated to require the formation of F1s in quantity, habitat-mediated superiority in F1s, and highly specific habitat conditions.
In order to find new acetylcholinesterase inhibitors from natural sources which have therapeutic potential in the treatment of Alzheimer's disease, the chloroform : methanol (1 : 1) extracts of five Lycopodium species ( L. clavatum L., L. selago L., L. annotinum L., L. alpinum L., and L. complanatum ssp. chamaecyparissus A. (Br.) Döll.), growing in Turkey (Lycopodiaceae), were screened in vitro by the Ellman spectrophotometric method at 1 mg/ml concentration. Among these extracts, only the extract of L. clavatum was found to be active (49.85 %). Bioassay-guided fractionation of the chloroform extract of L. clavatum led to the isolation of alpha-onocerin (IC 50 = 5.2 microM), a well-known triterpenoid, as the responsible compound for the activity.
Changes in land use/land cover have important consequences on the management of natural resources including soil and water quality, global climatic systems and biodiversity. This study analysed the spatial and temporal pattern of land use/land cover change in the Camili forest planning unit that includes the Camili Biosphere Reserve Area within the Caucasian hotspot, in the northeast corner of Turkey. To assess the patterns during a 33-year period, the necessary data were obtained from forest stand maps and evaluated with Geographic Information Systems and FRAGSTATS. Results showed that the total forested areas increased from 19 946Á5 ha (78Á6% of the study area) in 1972 to 20 797Á3 ha (81Á9 per cent) in 2005 with a slight net increase of 851 ha. Softwood cover types (411Á8 ha) completely transitioned to other cover types over 33-year period. In terms of spatial configuration, the total number of forest fragments increased from 172 to 608, and mean size of forest patch (MPS) decreased from 147Á7 ha to 41Á8 ha during the period. Nearly 84 per cent of the patches in 1972 and 93 per cent of them in 2005 generally seem to concentrate into 0-100 ha patch size class, indicating more fragmented landscape over time that might create a risk for the maintenance of biodiversity of the area. There were apparent trends in the temporal structure of forest landscape, some of which may issue from mismanagement of the area, social conflict, and illegal utilization of forest resources due to ineffective forest protection measurements. The study revealed that it is important to understand both spatial and temporal changes of land use/land cover and their effects on landscape pattern to disclose the implications for land use planning and management.
Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 lg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform extract was active against HSV (16-8 lg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16-4 lg/ml and 32-4 lg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS) and identified lycopodine as the major alkaloid.
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