Random Amplified Polymorphic DNA Analysis in Section \u3cem\u3ePnigma\u3c/em\u3e of the Genus \u3cem\u3eBromus\u3c/em\u3e L.

The section Pnigma consists of about 60 species. It was shown that Eurasian species of the section with the same ploidy level have similar nuclear DNA contents (Tuna et al., 2001). A linear correlation between nuclear DNA content and ploidy level was also found (Tuna et al., 2001). Furthermore, karyotypes of Eurasian species are similar (Tuna et al., 2004a) but differ from the North American species (Tuna et al., 2004b). Yet, the genetic relationship among species within the section is poorly known (Armstrong, 1991). The objective of this study was to assess the phylogenetic relationships among species of section Pnigma by using the RAPD technique

Identification of a Male-Specific Amplified Fragment Length Polymorphism (AFLP) and a Sequence Characterized Amplified Region (SCAR) Marker in Eucommia ulmoides Oliv.

Eucommia ulmoides Oliv. is a dioecious species. Currently, there is no method to identify the sex during the juvenile stage that lasts a relatively long time. This study aimed to develop a sex specific Amplified Fragment Length Polymorphism (AFLP) marker for Eucommia ulmoides Oliv. Of a total of 64 AFLP primer combinations screened, primer combination E-ACA/M-CTT produced a 350 bp male-specific marker. This 350 bp AFLP marker was converted into a 247 bp Sequence Characterized Amplified Region (SCAR) marker. Results suggest that the SCAR marker can be utilized for early sexual identification in Eucommia ulmoides Oliv., and it will greatly facilitate future breeding programs

Screening of desert plants for use against bacterial pathogens in fish

The antibacterial activity of aqueous extracts of 104 desert plant species was studied on the fol- lowing fish bacterial pathogens: Aeromonas hydrophila, Photobacterium damselae subspecies piscicida, Streptococcus iniae, and Vibrio alginolyticus. Seventeen plant species had antibacte- rial activity, as identified by disk diffusion assay. The pathogen P. damselae was sensitive to all 17 active extracts except Peganum harmala and a high inhibitory effect (14-19.5 mm) was pro- duced by Anchusa strigosa, Hammada scoparia, Achillea fragrantissima, Pulicaria crispa and Loranthus acaciae. The pathogens A. hydrophila and V. alginolyticus were inhibited by H. sco- paria, L. acaciae, and P. harmala (7-20.5 mm). The pathogen S. iniae was inhibited by Ochradenus baccatus and Reseda stenostachya (10.5 mm). The benefits of using desert plants as an alternative to conventional antibiotics are discussed

Population genetic structure and the conservation of isolated populations of Acacia raddiana in the Negev Desert

There is much concern over the high mortality of many populations of Acacia raddiana, a keystone tree species in the Negev desert of Israel. We used random amplified polymorphic DNA (RAPD) to assess patterns of genetic variation within and among 12 populations of A. raddiana from the Arava (Syrian-African Rift) valley and western Negev. A high level of genetic polymorphism was recorded within populations. An analysis of molecular variance (AMOVA) showed that about 59.4% of total genetic variance occurred among populations, which is considerably greater population differentiation than that recorded for other outbreeding species. Cluster and principal coordinates analyses and AMOVA indicate that the western Negev and Arava valley populations are highly differentiated. We suggest that there may have been two invasions of A. raddiana into Israel: one across the northern Sinai/Gaza Strip area into the western Negev, with some plants reaching the Dead Sea and a second invasion across the southern part of the Sinai peninsula, or even from Saudi Arabia, up to the Arava valley. From the conservation point of view, each population should be conserved separately because they are genetically highly differentiated and loss of any one population would lead to a dramatic loss of genetic variation. The mixing of genetically distinct populations may give rise to outbreeding depression (particularly because of GXE interactions). An obvious first step to the maintenance of this species' genetic diversity is the separate management of the western Negev and Arava valley populations because of their different evolutionary histories. © 2002 Elsevier Science Ltd. All rights reserved.Articl

Water status of isolated Negev desert populations of <I>Acacia raddiana </I>with different mortality levels

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Direct effect of CD on glutathione s-transferase and glutathione reductase from <em>Calystegia sepium</em>.

Interactions between heavy metals, glutathione, glutathione S-transferase (GST), and glutathione reductase (GR) are being investigated by many working groups, but evaluation of the direct effect of Cd2+ on these enzymes in vitro is lacking. We report here the effect of cadmium (10, 50, 100, 250 mu M CdSO4) on partially purified enzymes from Calystegia sepium. Plants were grown under normal field conditions without metals and the enzymes were extracted by Tris buffer and partially purified by ammonium sulphate fractionation and gel filtration. Glutathione S-transferase activity was measured with different substrates, i. e., 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrobenzylchloride (NBC), and the herbicide Fluorodifen. GST activity was significantly lower in leaf compared to stem, flower, and rhizome and the inhibitory effect of Cd was obtained with NBC and Fluorodifen substrates at 250 mu M. There was no effect of Cd on GR activity up to 250 mu M