Showing papers in "Journal of Biological Research in 2013"

Fish dietary patterns in the eutrophic Lake Volvi (East Mediterranean)

Abstract: Fish trophic ecology, food preferences, diet composition and diet overlap between coexisting species have been an issue of research for years (e.g. Hynes, 1950; Men delson, 1975; Wootton, 1999). Knowledge of fish diet is important, among others, in defining the role of fish species in a system, their interand intra-specific relationships and their functioning within food webs (Pauly et al., 1998; Stergiou & Karpouzi, 2002), while it has been used for monitoring and management purposes (Zambrano et al., 2006). Furthermore, fish trophic ecology (trophic guilds, feeding habits) has been incorporated, among other metrics, in evalu ating systems for the assessment of the ecological quality of the surface water ecosystems according to the European Water Framework Directive 2000/60/ EC (European Commission, 2000). Fish feeding ecology and food preferences have been described for several marine and freshwater spe cies (see Froese & Pauly, 2012). Especially for the Mediterranean region, such data is of major significance, due to the particulate importance of Mediterranean systems as biodiversity hotspots (Griffiths et al., 2004) and their recognized differences from other temperate systems (Alvarez Cobelas et al., 2005). Fish communities in Greek lakes are characteri zed by the dominance of omnivorous cyprinids (Bobori & Economidis, 2006; Economou et al., 2007) and the rarity of piscivorous species. However, despite their wide dispersal, data concerning their diet composition are limited with most of them referring to a spe cific species from one lake (e.g. Iliadou, 1991; Po li tou et al., 1993; Kleanthidis & Sinis, 2001; Chrisafi et al., 2007; Gkenas et al., 2012). The present study is the first effort to comprise information on the diet preferences of the most commercial fish species in Lake Volvi. The objectives we Journal of Biological Research-Thessaloniki 19: 139 – 149, 2013 J. Biol. Res.-Thessalon. is available online at http://www.jbr.gr Indexed in: WoS (Web of Science, ISI Thomson), SCOPUS, CAS (Chemical Abstracts Service) and DOAJ (Directory of Open Access Journals)

Quantitative analysis of nucleolar chromatin distribution in the complex convoluted nucleoli of Didinium nasutum (Ciliophora)

Abstract: We have earlier shown that the typical Didinium nasutum nucleolus is a complex convoluted branched domain, comprising a dense fibrillar component located at the periphery of the nucleolus and a granular component located in the central part. Here our main interest was to study quantitatively the spatial distribution of nucleolar chromatin structures in these convoluted nucleoli. There are no \"classical\" fibrillar centers in D.nasutum nucleoli. The spatial distribution of nucleolar chromatin bodies, which play the role of nucleolar organizers in the macronucleus of D.nasutum, was studied using 3D reconstructions based on serial ultrathin sections. The relative number of nucleolar chromatin bodies was determined in macronuclei of recently fed, starved D.nasutum cells and in resting cysts. This parameter is shown to correlate with the activity of the nucleolus. However, the relative number of nucleolar chromatin bodies in different regions of the same convoluted nucleolus is approximately the same. This finding suggests equal activity in different parts of the nucleolar domain and indicates the existence of some molecular mechanism enabling it to synchronize this activity in D. nasutum nucleoli. Our data show that D. nasutum nucleoli display bipartite structure. All nucleolar chromatin bodies are shown to be located outside of nucleoli, at the periphery of the fibrillar component.

Fulvia fragilis (Forsskal in Niebuhr, 1775) (Bivalvia: Cardiidae), first record of an alien mollusk in the Gulf of Thessaloniki (inner Thermaikos gulf, North Aegean Sea, Greece).

Abstract: Fulvia fragilis (Forsskal in Niebuhr, 1775) is a medium to large pelecypod bivalve (up to 75 mm), that belongs to the family Cardiidae and the subfamily Laevicardi i nae (Keen, 1937; Schneider, 1995). The species has a fragile and light almost circular shell with a sculpture of 41 ribs (34-52). The colour of the shell is whitish to yellow externally, with a purple stain only on the umbo and internally white with purple at the posterior third and sometimes at the umbonal cavity (www. ciesm.org/atlas). The species is native to the Indian Ocean and East African coasts, the Persian Gulf and the Red Sea (Vidal, 1994). Fulvia fragilis, progressively following the patterns of Lessepsian migration initially, spread in the Eastern Mediterranean Sea penetrating through the Suez Canal. The first confirmed record of its presence in the Suez Canal is that of Bavay as early as 1898 and the first confirmed Mediterranean record was made in Israel (Barash & Damin, 1973). The bivalve spread along the Eastern Mediterranean coast successively to Southern Turkey (Lindner, 1988) and Tunisia (Passamonti, 1996). Findings in these areas were made in locations visited only by small boats, so dispersal via shipping must be excluded. Stable populations of the bivalve are reported in the Western Mediterranean Sea, on the Spanish coast (Go fas & Zenetos, 2003; Zenetos et al., 2004a) and in par ticular in the Delta of Ebro River (Lopez Soriano et al., 2009). The authors do not relate the appearan ce of the species directly to accidental transportation Journal of Biological Research-Thessaloniki 20: 228 – 232, 2013 J. Biol. Res.-Thessalon. is available online at http://www.jbr.gr Indexed in: WoS (Web of Science, ISI Thomson), SCOPUS, CAS (Chemical Abstracts Service) and DOAJ (Directory of Open Access Journals)

First report of Botanophila turcica (Diptera: Anthomyiidae) on safflower Carthamus tinctorius L. in Greece.

Abstract: Saffron thistle Carthamus lanatus L. (Compositae) is a winter annual weed growing in southern Europe from the southern Iberian to the southern Balkan pe nin sulas (Tutin et al., 1976). It has spread invasively to other parts of the world and became particularly trou blesome in dry pastures and cereal crop areas of southern Australia (Aeschlimann, 1997 and referen ces therein). A close relative of saffron thistle is the cul tivated safflower Carthamus tinctorius L., a crop cul tivated worldwide in the winter or spring in semia rid regions as a source of oil for both human consumption and industrial uses. In Greece, safflower is cultivated for biodiesel production (Panoutsou et al., 2008). The anthomyiid genus Botanophila Lioy includes 70 species recorded from Europe (Michelsen, 2011). Bo tanophila turcica belongs to a subgroup of Bota no phi la known as rosette-crown flies, because their larvae attack young, overwintering rosettes of thistles, knapweeds and other Compositae. Botanophila turcica appears to be widespread in the Mediterranean a rea as the second author has seen it at France, Spain, Greece and Turkey. Till now, B. turcica was reported to infest saffron thi stle but no relevant report on safflower has been evident.

Initial evidence on auto-regulation of prhK operon and its potential working model for the regulation of hrp regulon in Ralstonia solanacearum

Abstract: Type iii secretion system (T3ss) is conserved in ma ny plant and animal bacterial pathogens and this syringe-like protein-secretion system is essential for their virulence and host specificity. Bacteria use T3ss to inject bacterial proteins, so-called type iii effectors into host cytoplasm to subvert host defense signaling and facilitate bacterial colonization in host (hueck, 1998; galán & Collmer, 1999; galán & Wolf-Watz, 2006; Zhou & Chai, 2008; Lewis et al., 2009). in bacterial plant pathogens, the T3ss is encoded by a cluster of approximately 20 hrp (hypersensitive response and pathogenicity) genes that are organized into se ve ral operons (arnold et al., 2003; Valls et al., 2006). Ralstonia solanacearum is a causative agent of ba cte rial wilt disease in almost 200 crop and ornamental plant species; it is soil-borne, gram-negative, and has been studied as a model plant vascular pathogen (Ya buuchi et al., 1995; schell, 2000; Denny, 2006). The construction of T3ss in R. solanacearum is strongly influenced by the growth environment. its expression is repressed in nutrient-rich condition, well induced in nutrient-poor condition and greatly enhanced when stimulated with plant signals (arlat et al., 1992; genin et al., 1992; Mukaihara et al., 2004; Yoshimochi et al., 2009b). T3ss is positively controlled by hrpB, which belongs to the araC-family transcriptional regulator. hrpB might directly bind to hrpII box, a conserved Dna motif in the promoters of most of its target ge Journal of Biological Research-Thessaloniki 20: 305 – 311, 2013 J. Biol. Res.-Thessalon. is available online at http://www.jbr.gr indexed in: Wos (Web of science, isi Thomson), sCOPUs, Cas (Chemical abstracts service) and DOaJ (Directory of Open access Journals)