Genetic diversity and pathogenicity of Pseudomonas syringae pv. aptata isolated from sugar beet

Pseudomonas syringae pv. aptata is the causal agent of bacterial leaf spot disease of sugar beet (Beta vulgaris). During 2013, 250 samples were collected from leaf lesions with typical symptoms of bacterial leaf spot in commercial fields of sugar beet in Serbia, and 104 isolates of P. syringae pv. aptata were obtained. Identification and characterization was performed using biochemical, molecular and pathogenicity tests. Identification included LOPAT tests and positive reactions using primers Papt2F and Papt1R specific for P. syringae pv. aptata. Repetitive (rep) sequence‐based PCR typing with ERIC, REP and BOX primers revealed high genetic variability among isolates and distinguished 25 groups of different fingerprinting profiles. Pulse‐field gel electrophoresis (PFGE) and multilocus sequence analysis (MLSA) of representative isolates showed higher genetic variability than in rep‐PCR analysis and distinguished three and four major genetic clusters, respectively. A pathogenicity test performed with 25 representative isolates on four cultivars of sugar beet confirmed the occurrence of leaf spot disease and showed correlation between the most aggressive isolates and the genetic clusters obtained in MLSA. All these findings point to the existence of several lines of P. syringae pv. aptata infection in Serbia that are genetically and pathologically different.     

Effects of cage fish farming on phytoplankton community structure,biomass and primary production in an aquaculture area in the middle Adriatic Sea

In this study, we investigated the physical, chemical and biological parameters of the water column at two stations under different trophic conditions during a 1‐year period (from September 2005 to September 2006) in an aquaculture area. The investigation was performed monthly at a station inside the fish farm in Maslinova Bay (middle Adriatic Sea, Croatia) and at a control station located in the Hvar Channel in the vicinity of the farm. The results showed that the concentrations of dissolved nutrients were slightly enhanced at the farm station in comparison with the control station, although those differences were not statistically significant, nor were the differences in oxygen saturation recorded during the investigation period. As opposed to the chemical parameters, considerably higher deviations were recorded for biological parameters as demonstrated by a significant increase in phytoplankton biomass and primary production (measured in situ) at the farm station, particularly during the summer season. Phytoplankton community structure analysis showed that the phytoplankton composition at the farm was mostly determined by seasonal changes rather than by the influence of fish farming. In Maslinova Bay, no causal links were identified between increased biomass and the appearance of toxic species.     

Influence of cytokinins on in vitro morphogenesis in root cultures of Centaurium erythraea—Valuable medicinal plant

The purpose of this work was to acquire more information on the capacity of in vitro grown Centaurium erythraea Gillib. normal and hairy root cultures to simultaneously regenerate adventitious buds and to evaluate the variations induced on regeneration response by treatments with six cytokinins. Explants from normal and hairy root cultures were cultured on half-strength MS medium (1/2 MS) with kinetin (KIN), N⁶-benzylaminopurine (BA), 6-γ,γ-dimethylallylaminopurine (2IP), N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), 1-Phenyl-3-(1,2,3-thiadiazol-5-yl)urea (TDZ) and 6-[4-Hydroxy-3-methyl-but-2-enylamino]purine (ZEA), used alone in six different concentrations. The average number of adventitious buds per explant was promoted by all of cytokinin treatments. Urea-type cytokinins, TDZ and CPPU were more effective for the induction the morphogenesis of adventitious buds than adenine-type cytokinins. We found that the 1.0 μM CPPU induced the largest number (25.6, 18.2, respectively) of adventitious buds in normal and hairy root culture. TDZ-supplemented media induced highest number of adventitious buds (24.2) from normal root explant, but from hairy root explant average number of buds is lower (20.5). Regenerated shoots were excised and placed on 1/2 MS medium without hormone. The rooted plantlets were successfully acclimatized in greenhouse conditions.     

Eighty-year review of the evolution of landscape ecology: from a spatial planning perspective

Landscape Ecology - Sustainable spatial development requires the establishment of a balance between rational land use and the protection of nature, ecosystems and biodiversity on various spatial...     

Editorial

Skadar Lake, a large, shallow, subtropical lake on the Albanian frontier in south-western Yugoslavia, supports a commercial fishery which annually yields nearly a thousand metric tons. Examination of catch statistics plus documentation of increasing effort during 1947 through 1973 reveals a declining catch per unit of effort. Water quality has not changed since 1952. However, changes in gear, effort, and exploitation have apparently caused major shifts in species composition and size of the catch. Rapid technological changes in gear coupled with potential environmental degradation may lead to decreased stocks and over-exploitation. Only by instituting a comprehensive management programme, within the context of international cooperation and sound ecological information, can a high sustained yield be maintained and over-exploitation of commercially important fish stocks in Skadar Lake be presented.     

Veterinary public health in a problem-based learning curriculum at the Western University of Health Sciences

As detailed in the Association of Schools of Public Health / Association of American Veterinary Medical Colleges 2007 Joint Symposium on Veterinary Public Health, veterinary public health (VPH) can no longer be viewed as a unique sub-specialty of veterinary medicine. Rather, its practice pervades nearly every aspect of the veterinary profession, regardless of whether the practitioner is engaged in small-animal, large-animal, research, corporate, or military practice. In congruence with the practice of VPH, the teaching of VPH should also pervade nearly every aspect of veterinary education. Accordingly, at Western University of Health Sciences, College of Veterinary Medicine (WU-CVM), public health is not simply taught as an individual course but, rather, is interwoven into almost every aspect of the curriculum, continually emphasizing the relevance of this discipline to the practice of veterinary medicine. This article outlines the teaching philosophy of WU-CVM, provides an overview of the curriculum, and describes the integral nature of public health throughout all four years of the educational program.     

Preliminary assay on the antioxidative activity of Maydis stigma extracts

Antioxidative effects of Maydis stigma methanolic extracts were studied on the level of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured spectrophotometrically by the TBA-test. The most significant inhibition of lipid peroxidation was observed when methanolic extracts of fully developed, mature corn silk were applied. The same test, performed after fractionation of the most active extract, showed that most of the activity was concentrated in fractions with moderate lipophilicity, containing phenolic acids, flavonoid aglyca and resembling monosides.     

Pathogene Mikroorganismen als Begleiter und Mortalitätsfaktoren des SchwammspinnersLymantria dispar L. und des amerikanischen WebebärenHyphantria cunea Drury

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Die Nahrungswahl und das Auftreten der Pflanzenschädlinge

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