Inhibition of Vibrio spp. by 2‐Hydroxyethyl‐11‐hydroxyhexadec‐9‐enoate of Marine Cyanobacterium Leptolyngbya sp. LT19

Seven marine cyanobacteria were isolated from two regions of the Gulf of Thailand and evaluated by the agar diffusion method for antibacterial activity. Inhibitory compound was purified from the crude methanol extract and its structure was elucidated based on extensive spectroscopic analysis, including IR, 1D and 2D NMR spectra as well as mass spectrometry. A novel antimicrobial compound produced by the marine cyanobacterium Leptolyngbya sp. LT19 was identified to be a 2‐hydroxyethyl‐11‐hydroxyhexadec‐9‐enoate which has so far never been reported in microorganisms. Biological assays revealed that this novel compound exhibited antibacterial activities against the Gram‐negative, persistent shrimp pathogens, Vibrio harveyi and V. parahaemolyticus with minimal inhibitory concentration of 250–1000 and 350–1000 μg mL^?1 respectively.     

Studies on phenology and harmfulness of Aceria carvi Nal. (Acari: Eriophyidae) on caraway, Carum carvi L., in the Czech Republic

Caraway (Carum carvi L.) belongs to the traditional crops which have been grown in Bohemia since the end of the 19th century. Depressaria daucella (Denis and Schiffermüller) and Aceria carvi Nal. are two main pests of caraway in the Czech Republic. The latter becomes a serious problem in major caraway-growing areas. So far, no effective method for its control is known. The aim of this paper is to describe the phenology of symptoms of A. carvi infestation and damage caused by this pest. Our observation revealed that although A. carvi overwinters hidden within leaves of young caraway plants, the first symptoms are usually not visible before the start of flowering. Though the initial density of the pest is low, the mite population multiplies during the season when the pest attacks plant tissues and causes development of galls on leaves and flowers. Comparison of healthy plants and plants infested by A. carvi showed that infested plants had significantly more umbels but produced far fewer seeds, and the yield of caraway was thus substantially decreased. Recommendations for crop management methods to suppress the pest are given.Electronic Supplementary Material Supplementary material is available for this article at     

Distribution and abundance of small rodents in Croatian forests

The relative abundance and the population development of small rodents were investigated on 17 sites in Croatian forests from September 1999 through June 2003. Common snap traps were set for two or three nights along transect lines in different forest types. In 27,598 trap–nights, 2,151 specimens were trapped. Small rodents were present in up to 45% of the traps in pedunculate oak forests dominated by Quercus robur L. In common beech forests with a predominance of Fagus sylvatica L., the percentage of occupied traps reached 59%. At most sites the following species were dominant:Clethrionomys glareolus Schr., Apodemus agrarius Pall. and A. flavicollis Melch. Additionally, in a forest community of Carpino betuli-Quercetum roboris typicum R., the absolute number of small rodents was calculated by means of the standard minimum method. The minimum rodent density was observed in April 2003 with 11.63 n/ha (number of specimens per hectare). The maximum was reached in March 2001 with 82.03 n/ha. Near the same site, the absolute number of the small rodent population was estimated using the Y method in spring 2001 as approximately 101.34 n/ha. In general, the abundance of small rodents was dependent on the forest seed crop.     

Larssoniella duplicati n.sp. (Microsporidia, Unikaryonidae), a newly described pathogen infecting the double-spined spruce bark beetle, Ips duplicatus (Coleoptera, Scolytidae) in the Czech Republic

Larssoniella duplicati n.sp. infects the midgut muscularis, the Malpighian tubules, and the ovaries of adult Ips duplicatus (Sahlb.) in the Czech Republic. The microsporidian attacks up to 50% of the population. Oval spores of two sizes, 3–3.5×1.5–2 and 2–2.5×1.5 μm have the polar filament coiled in 6/7 coils, representing primary and environmental spores, respectively. In early sporogony the young spores produce long electron dense threads and tubules of secretions, which remain fixed around the spore and avoid their free release during dissection of infected hosts. The microsporidian was not found in associated bark beetles such as Ips typographus (L.), or I. amitinus (Eichh.) and others.     

Predictive value of a model of the flight activity of Adoxophyes orana (Lep.: Tortricidae)

In 1992–2002, the flight activity of Adoxophyes orana (AO) was investigated using pheromone traps placed in apple orchards in five localities in Central and Eastern Bohemia. The cumulative catches of AO were plotted against time expressed as the sum of day-degrees (D°) above 8°C and approximated by a Richards’ function. This model was constructed using the numbers of AO males caught by pheromone traps from 1992–1998 at all the localities. The flight of the overwintering generation of AO began when 200 D° had accumulated, culminated at 300 D° and ceased at 430 D°, irrespective of locality. The high predictive ability of the model was validated using data from one locality for 2001–2003. It was impossible to construct a similar model to predict the flight activity of the summer generation because its dependence on D° varied greatly between localities and years.     

Relation between combustion heat and chemical wood composition during white and brown rot

Summary The results of respective investigations indicate that during white rot the combustion heat of wood (Q_exp (J/g)) remained virtually unchanged and at the greatest extent of decomposition it was in the range also found in non-rotten wood. During brown rot the combustion heat of wood samples increased, beginning at a weight loss of 20–30%. The difference between Q_exp and the weighted mean of combustion heat values of isolated chemical wood components (Q_cal) were neglectable. If Q_exp values measured for each sample were taken as 100%, then Q_cal averaged from 101.1–105.6% and from 97.4–108.2% during white and brown rot, respectively. The Q_cal calculation error is expressed as coefficient k; it varies depending on the accuracy and selectivity of the separation methods used.     

A 2D quantum walk simulation of two-particle dynamics

Multidimensional quantum walks can exhibit highly nontrivial topological structure, providing a powerful tool for simulating quantum information and transport systems. We present a flexible implementation of a two-dimensional (2D) optical quantum walk on a lattice, demonstrating a scalable quantum walk on a nontrivial graph structure. We realized a coherent quantum walk over 12 steps and 169 positions by using an optical fiber network. With our broad spectrum of quantum coins, we were able to simulate the creation of entanglement in bipartite systems with conditioned interactions. Introducing dynamic control allowed for the investigation of effects such as strong nonlinearities or two-particle scattering. Our results illustrate the potential of quantum walks as a route for simulating and understanding complex quantum systems.     

Chemical analysis of three herbal extracts and observation of their activity against adults of Acanthoscelides obtectus and Leptinotarsa decemlineata using a video tracking system

Journal of Plant Diseases and Protection - Ethanol extracts of Rosmarinus officinalis, Lavandula angus-tifolia and Ruta graveolens were tested against adults of Acanthoscelides obtectus and...     

Spatial delineation of organic carbon-rich Colluvial soils in Chernozem regions by Terrain analysis and fuzzy classification

Colluvial soils are considered to be the direct result of accelerated soil erosion, resulting in accumulation of humus-rich soil material in terrain depressions and base parts of slopes. The organic carbon concentration in these soils and their depth make them an important organic carbon storage. Mapping the Colluvial soils, therefore, represents an important contribution in total carbon stock estimation. A method of delineating Colluvial soils is proposed by applying a combination of high resolution digital elevation model analysis and detailed field survey. Two models based on fuzzy classification of soil units were created using different topographic derivatives as the only input parameters to predict the Colluvial soil area on a morphologically diverse study site in the Southern Moravia, Czech Republic. The model that considers only the derivatives with a strong relationship to Colluvial soil occurrence reached 71% accuracy in Colluvial area delineation, while the model combining six commonly used derivatives showed less favorable results. The main advantage of the method lies in a low demand of input soil data and its relatively high accuracy.