Micropropagation of four Gentiana species (G. lutea, G. cruciata, G. purpurea and G. acaulis)

The growth of axillary shoots was initiated on nodal stem segments, excised from aseptically grown seedlings of Gentiana acaulis L., G. cruciata L., G. lutea L. and G. purpurea L. In later subcultures, a basal callus tissue developed on the shoots, giving rise to de novo formed buds. Optimum benzyladenine and indoleacetic acid combinations for shoot development were established. They were slightly different in the four species. From 35-70% of shoots rooted spontaneously, except in G. lutea, in which adventitious roots were induced by applying naphthaleneacetic acid. It was conduded that the four Gentiana species were amenable to propagation in vitro. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evaluation of agronomic traits in tissue culture – derived progeny of bird's-foot trefoil

Two newly selected Lotus corniculatus cultivars (Bokor and Zora), introduced recently as pasture legumes, were studied with respect to their in vitro regeneration capacity and field performance of R₁ regenerates. Multiple buds were induced in callus tissues derived from apical buds, petioles, leaf and cotyledon explants. The rooted regenerates, acclimated in a greenhouse, were fertile. Seeds from the R₁ generation were sown in the field and the plants found to be superior to controls in stem height and green mass production.     

Endogenous Methyl Salicylate in Pathogen-Inoculated Tobacco Plants

The tobacco (Nicotiana tabacum) cultivar Xanthi-nc (genotype NN) produces high levels of salicylic acid (SA) after inoculation with the tobacco mosaic virus (TMV). Gaseous methyl salicylate (MeSA), a major volatile produced in TMV-inoculated tobacco plants, was recently shown to be an airborne defense signal. Using an assay developed to measure the MeSA present in tissue, we have shown that in TMV-inoculated tobacco plants the level of MeSA increases dramatically, paralleling increases in SA. MeSA accumulation was also observed in upper, noninoculated leaves. In TMV-inoculated tobacco shifted from 32 to 24°C, the MeSA concentration increased from nondetectable levels to 2318 ng/g fresh weight 12 h after the temperature shift, but subsequently decreased with the onset of the hypersensitive response. Similar results were observed in plants inoculated with Pseudomonas syringae pathovar phaseolicola, in which MeSA levels were highest just before the hypersensitive response-induced tissue desiccation. Transgenic NahG plants unable to accumulate SA also did not accumulate MeSA after TMV inoculation, and did not show increased resistance to TMV following MeSA treatment. Based on the spatial and temporal kinetics of its accumulation, we conclude that tissue MeSA may play a role similar to that of volatile MeSA in the pathogen-induced defense response.     

Adaptive significance of amylase polymorphism in Drosophila

Laboratory populations of D. busckii flies were kept for one generation on media containing different carbohydrate sources (maltose and rice, potato or maize starch). The flies maintained on standard potato medium served as a control. Progeny were analyzed for -amylase activity and Amy-electromorph frequencies.Spectrophotometrically assayed amylase activity was highest in the flies cultured on potato starch medium and lowest in specimens kept on maltose. Carbohydrate source in some substrates affected both frequencies of Amy-alleles and Amy-genotypes. Phenotypic differences at a biochemical level, i.e. in -amylase activity, might be connected to Amy-structural gene polymorphism in the examined Drosophila species.     

Organic aggregates formed by benthopleustophyte brown alga Acinetospora crinita (Acinetosporaceae,Ectocarpales)

This work presents the elemental, polysaccharide, and fatty acid compositions of benthic aggregates formed by the filamentous brown alga Acinetospora crinita, which are widely spread on the rocky bottoms of the Mediterranean Sea. The aggregates can be characterized as mineralized centers in which regeneration of nutrients and recycling of dissolved organic matter actively occur and favor the development of an abundant phytoplankton community. Analyses of the stable isotopes of C and N display their marine origin and could provide evidence of the processes that occur inside/outside of the aggregates. The monosaccharide compositions of Adriatic and Tyrrhenian mucilages produced by brown alga A. crinita were quite similar. In particular, the Adriatic sample compositions resembled the average composition of the Tyrrhenian high molecular weight exopolymers, and the observed differences could be ascribed to different degradation stages. The fatty acid patterns found for the aggregates were similar to those observed in the isolated A. crinita algae with variable contributions from embedded diatom species. The bacterial contribution to the fatty acid pool was quite low, most likely due to the known poor conditions for their heterotrophic growth.     

Circulating tumor cell isolation,culture, and downstream molecular analysis

Circulating tumor cells (CTCs) are a major contributor of cancer metastases and hold a promising prognostic significance in cancer detection. Performing functional and molecular characterization of CTCs provides an in-depth knowledge about this lethal disease. Researchers are making efforts to design devices and develop assays for enumeration of CTCs with a high capture and detection efficiency from whole blood of cancer patients. The existing and on-going research on CTC isolation methods has revealed cell characteristics which are helpful in cancer monitoring and designing of targeted cancer treatments. In this review paper, a brief summary of existing CTC isolation methods is presented. We also discuss methods of detaching CTC from functionalized surfaces (functional assays/devices) and their further use for ex-vivo culturing that aid in studies regarding molecular properties that encourage metastatic seeding. In the clinical applications section, we discuss a number of cases that CTCs can play a key role for monitoring metastases, drug treatment response, and heterogeneity profiling regarding biomarkers and gene expression studies that bring treatment design further towards personalized medicine.     

Sublethal effects of NeemAzal- T/S botanical insecticide on Dutch and Serbian populations of Encarsia formosa (Hymenoptera: Aphelinidae)

Sublethal effects of an azadirachtin-based botanical insecticide (commercial product NeemAzal-T/S) on behaviour, life history traits and population growth of one commercial (Dutch strain, D) and two Serbian populations (Bujanovac, B; Negotin, N) of Encarsia formosa Gahan were evaluated in laboratory bioassays. In a two-choice test, parasitoids from all tested populations preferred to parasitise the untreated whitefly nymphs over those treated with 50, 25, 12.5, 6.25 and 3.12?mg/l of azadirachtin. All concentrations caused significant deterrent effects after 24?h, and the following deterrence indices were calculated: 9.7–60.9% (B), 5.5–57.5% (N) and 12.9–63.5% (D). The longevity of adults exposed for 48?h to residues of the botanical insecticide (applied at LC₅₀) was shorter (1.5–1.7 days) than that of control wasps. Both daily and total parasitism were significantly reduced (by 41.7, 48.3 and 60.1% for N, D and B, respectively) compared to control, as well as adult emergence in the F₁ generation. The instantaneous rate of increase (r_i) of surviving adults was also significantly reduced (by 13.2, 19. 3 and 20.5%, for populations N, B, and D, respectively). Adults from all tested populations, emerged from pupae treated with the botanical insecticide applied at LC₅₀, showed reduced parasitism, adult emergence, and r_i levels, but the reduction was significant only for adult emergence of B and r_i of B and N. Juvenile development of the parasitoid in treated pupae was significantly extended, compared to control. The implications of these results on integrated control of the greenhouse whitefly are discussed.     

Rocky-shore unconformities marking the base of Badenian (Middle Miocene) transgressions on Mt. Medvednica basement (North Croatian Basin,Central Paratethys)

Badenian (Middle Miocene) transgressive deepening-upward successions located in the NE part of Mt. Medvednica (North Croatian Basin, Pannonian Basin System) unconformably overlie Mesozoic basement. Triassic and Upper Cretaceous limestone pebbles, cobbles, and boulders of the Badenian basal conglomerates display abundant in situ bivalve borings of Gastrochaenolites and sponge borings of Entobia. This Gastrochaenolites-Entobia ichnoassemblage is related to the Entobia subichnofacies of the Trypanites ichnofacies, characterizing littoral rocky-shore environments (wave-cut platforms and marine transgressive surfaces with a low or null rate of sedimentation). Gastrochaenolites torpedo, Gastrochaenolites lapidicus, and Entobia recorded in Badenian basal conglomerates (compared with modern Northern Adriatic rocky-shore environments), enabled more precise palaeoenvironmental interpretations. The occurrence of G. torpedo (produced by lithophaginid bivalves) on all sides of individual limestone lithoclasts in the Gornje Ore?je basal conglomerate, coupled with truncation of the formation (possibly indicating multiphase colonization), reflect gravel transport, roll-over, overturning and erosion by wave action in high-energy rocky-shore settings. Gornje Psarjevo-2 basal conglomerate boulders were probably not subjected to significant movement and abrasion, as suggested by good preservation of both G. lapidicus (potentially produced by gastrochaenid bivalves), associated G. torpedo, as well as abundant shallow Entobia borings. The Badenian Gastrochaenolites-Entobia ichnoassemblage also could be the result of a composite development. However, direct cross-cutting relationships between G. torpedo and G. lapidicus and/or Entobia were rarely observed. In addition, Badenian boring tracemakers might have coexisted at the same water depth. Northeast Mt. Medvednica Badenian successions probably formed during different Central Paratethys transgressive pulses (NN5 and NN6 Zones). However, exact timing of Badenian transgressions, stratigraphic correlations and tectono-eustatic implications are unresolved, due to sparsely integrated biostratigraphic and high-precision geochronological studies of Early–Middle Miocene North Croatian Basin deposits and due to the absence of a uniform biostratigraphic zonation and regional chronostratigraphic division of Central Paratethys.     

Adaptive significance of amylase polymorphism in Drosophila I. The geographical pattern of allozyme polymorphism at the amylase locus in Drosophila subobscura

Allelic variation at the Amy locus was studied in eight natural populations from the central and northern range of D. subobscura, and the geographical pattern of Amy polymorphism over the range of this species was described. Even though regional and local differences in gene frequencies were found, in general the same alleles occur at high, intermediate and low frequencies, in nearly all populations. There are no significant differences in allele frequencies, but there is significant difference in the degree of heterozygosity among groups of populations from the northern, central and southern range. An analysis of population subdivision indicates that heterogeneity within populations is higher than between populations. Genetic distance values indicate that there is a variable degree of geographical differentiation between local populations. Variability within and between continental and insular populations is also discussed.     

Induction of somatic embryogenesis and embryo development in Rumex acetosella L.

Axillary buds of the dioecious plant Rumex acetosella L. were isolated and cultured in vitro. The callus tissue which developed at the basal parts of the explants displayed a high capacity for shoot formation. This morphogenetic pattern was predominant on Murashige and Skoog (MS) medium supplemented with 2% sucrose, 2.2 mgl^-1 benzylaminopurine and 0.17 mgl^-1 indole-3-acetic acid. Somatic embryogenesis was induced when the osmolality of the medium was increased by adding 6% sucrose instead of 2%, or hexitols in addition to 2% sucrose. Most of the embryogenic calli were formed on the basal parts of leaf laminae and bracts. Development and maturation was strongly promoted by transferring the tissue to a solid or liquid medium lacking benzylaminopurine and indole-3-acetic acid and supplemented with 10 mgl^-1 gibberellic acid. The embryos germinated and developed into normal rosette plants when transferred to vermiculite moistened with hormone-free, half-strength MS salt solution. The histology of successive embryogenic stages is presented.