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Abstract: Amplified fragment length polymorphism (AFLP) markers were used to assess genetic relations of 32 Thymus populations belonging to seven species of genus Thymus, section Serpyllum, from Serbia. The collected species belong to three subsections: (1) Alternantes Klokov (Th. pulegioides L.), (2) Isolepides (Borbás) Halácsy (Th. glabrescens Willd., Th. marschallianus Willd., Th. pannonicus All.), and (3) Pseudomarginati (Braun ex Borbás) Jalas (Th. balcanus Borbás, Th. moesiacus Velen., Th. praecox Opiz). Analysis of molecular variance (AMOVA) revealed that most of the genetic diversity was attributable to differences among individuals within populations, while the remaining variability was almost equally distributed among species and among populations within species. The pairwise AMOVA analyses further showed that species differentiation was significant in all cases, except between Th. marschallianus and Th. pannonicus. All the individuals belonging to Th. pulegioides (subsection Alternantes) formed a well-supported clade, the most divergent from all other species in this study. This genetic differentiation of Th. pulegioides is supported by its morphological features because it is the only analyzed taxon having hairs only on the stem edges, and can easily be recognized by this character. According to our results, the subsection Isolepides is polyphyletic. Th. glabrescens is clearly separated from the other two species of this subsection (Th. marschallianus, Th. pannonicus). Although morphologically distinguishable by leaf indumentum, individuals belonging to Th. marschallianus and Th. pannonicus could not be differentiated at the molecular level. The species belonging to subsection Pseudomarginati formed a monophyletic clade, although not supported by high bootstrap value. The clade is further divided into three well-supported clades representing distinct species (Th. balcanus, Th. praecox and Th. moesiacus). In our study, the AFLP markers demonstrated that they could be suitable for studying complex genetic relationships, including frequent interspecies hybridization events, although strict reticulate evolutionary history could not be determined. All the population genetic parameters in the section Serpyllum suggest that the reproductive incompatibility between the species is very weak, which indicates a strong reticulating system, especially in the case when two or more species occur sympatrically. [Copyright &y& Elsevier]

Abstract: GC/MS was used to identify compounds of essential oils from seven Ocimum taxa (O. americanum L., O. basilicum L., O. campechianum Mill., O. x citriodorum Vis., O. kilimandscharicum Baker ex Gürke and three botanical varieties and cultivars of Ocimum basilicum L.: ‘Genovese’, var. difforme and var. purpurascens). Preliminary screening of their antibacterial activity was done against a number of common pathogens (Enterococcus faecalis, Enterococus faecium, Escherichia coli 0157:H7, Listeria monocytogenes, Listeria ivanovii, Proteus vulgaris, Staphylococcus aureus, Staphylococcus epidermis) using the filter paper disc agar diffusion technique, while further analyses were done by modification of the disc diffusion method. A broad variation in the antibacterial properties of investigated essential oils was observed. E. coli 0157:H7 was inhibited by O. basilicum ‘Genovese’ essential oil, while Ocimum americanum and Ocimum x citriodorum essential oils were the most effective against Enterococcus faecalis, Enterococcus faecium, P. vulgaris, S. aureus and S. epidermis. [Copyright &y& Elsevier]