Characterization of the essential oil volatiles of Satureja thymbra and Satureja parnassica: influence of harvesting time and antimicrobial activity

Seasonal variation in chemical composition of essential oils obtained from Satureja parnassica subsp. parnassica Heldr. & Sart ex Boiss. and Satureja thymbra L. was determined by GC and GC-MS analysis. The in vitro antibacterial activities of these essential oils were evaluated at two different initial levels against two common foodborne bacteria. Their minimum inhibitory concentration (MIC) and noninhibitory concentration (NIC) values were determined via an innovative automated technique, which was applied on a Malthus apparatus combining the conductance measurements with the common dilution method. The essential oil concentration fluctuated greatly during the period examined and established that the Satureja oils obtained during the flowering period were the most potent, exhibiting the lowest MIC values and retaining remarkable bactericidal properties. Thus, they represent an inexpensive source of natural antibacterial substances that exhibit potential for use in food systems to prevent the growth of foodborne bacteria and to extend the shelf life of the processed food.     

Behaviour of European sea bass,Dicentrarchus labrax L., in cages – impact of early life rearing conditions and management

European sea bass, Dicentrarchus labrax L., groups reared under different conditions during larval stages (mesocosm and intensive rearing) were monitored during on‐growing in sea cages until marketable size (350–400 g). Four caged groups were followed for a period of 17 months each at a pilot scale farm, where vertical distribution behaviour was monitored. This was performed while fish were under calm conditions, during feeding and when stress events occurred. Also during two specific periods: (i) spawning and (ii) high water temperature. Clear differences in the behavioural pattern of swimming depth, displacement and used space between the groups were observed. The individuals from the mesocosm rearing were more sensitive to human presence, showing stronger reactions (speed of displacement and vertical distribution). Most pronounced differences were observed during the ‘extreme’ warm period and the reproductive season. Within the seasons, European sea bass responded during feeding and stress showing a tendency to move deeper compared to calm conditions. The increased displacements were longer during feeding and stress.     

Accurate multiplex polony sequencing of an evolved bacterial genome

We describe a DNA sequencing technology in which a commonly available, inexpensive epifluorescence microscope is converted to rapid nonelectrophoretic DNA sequencing automation. We apply this technology to resequence an evolved strain of Escherichia coli at less than one error per million consensus bases. A cell-free, mate-paired library provided single DNA molecules that were amplified in parallel to 1-micrometer beads by emulsion polymerase chain reaction. Millions of beads were immobilized in a polyacrylamide gel and subjected to automated cycles of sequencing by ligation and four-color imaging. Cost per base was roughly one-ninth as much as that of conventional sequencing. Our protocols were implemented with off-the-shelf instrumentation and reagents.     

Contact-dependent demyelination by Mycobacterium leprae in the absence of immune cells

Demyelination results in severe disability in many neurodegenerative diseases and nervous system infections, and it is typically mediated by inflammatory responses. Mycobacterium leprae, the causative organism of leprosy, induced rapid demyelination by a contact-dependent mechanism in the absence of immune cells in an in vitro nerve tissue culture model and in Rag1-knockout (Rag1-/-) mice, which lack mature B and T lymphocytes. Myelinated Schwann cells were resistant to M. leprae invasion but undergo demyelination upon bacterial attachment, whereas nonmyelinated Schwann cells harbor intracellular M. leprae in large numbers. During M. leprae-induced demyelination, Schwann cells proliferate significantly both in vitro and in vivo and generate a more nonmyelinated phenotype, thereby securing the intracellular niche for M. leprae.     

Attention but not awareness modulates the BOLD signal in the human V1 during binocular suppression

Although recent psychophysical studies indicate that visual awareness and top-down attention are two distinct processes, it is not clear how they are neurally dissociated in the visual system. Using a two-by-two factorial functional magnetic resonance imaging design with binocular suppression, we found that the visibility or invisibility of a visual target led to only nonsignificant blood oxygenation level-dependent (BOLD) effects in the human primary visual cortex (V1). Directing attention toward and away from the target had much larger and robust effects across all study participants. The difference in the lower-level limit of BOLD activation between attention and awareness illustrates dissociated neural correlates of the two processes. Our results agree with previously reported V1 BOLD effects on attention, while they invite a reconsideration of the functional role of V1 in visual awareness.     

Perceptual deficits and the activity of the color-opponent and broad-band pathways at isoluminance

The deficits in texture, motion, and depth perception incurred in monkeys at isoluminance were compared with the responses of neurons of the color-opponent and broad-band systems in the lateral geniculate nucleus. Texture perception, assumed to be carried by the color-opponent system, and motion and depth perception, ascribed to the broad-band pathway, were all found to be compromised but not abolished at isoluminance. Correspondingly, both the color-opponent and the broad-band systems were affected at isoluminance, but the activity of the neurons in neither system was abolished. These results suggest that impairment of visual capacities at isoluminance cannot be uniquely attributed to either of these systems and that isoluminant stimuli are inappropriate for the psychophysical isolation of these pathways.     

INFLUENCE OF SODIUM CHLORIDE AND CALCIUM FOLIAR SPRAY ON HYDROPONICALLY GROWN PARSLEY IN NUTRIENT FILM TECHNIQUE SYSTEM

The effects of salinity [30 or 90 mM sodium chloride (NaCl)] and calcium (Ca) foliar application on plant growth were investigated in hydroponically-grown parsley (Petroselinum crispum Mill). Increasing salinity reduced fresh weight and leaf number. Calcium alleviated the negative impacts of 30 mM NaCl on plant biomass and leaf fresh weight but not in case of 90 mM. Plant height, leaf and root dry weight and root length did not differ among treatments. Total phenols increased with calcium application, chlorophyll b reduced by salinity, while total carotenoids increased with salinity and/or Ca application. Salinity reduced nutrient uptake [nitrate (NO₃), potassium (K), phosphorus (P) and Ca] and elemental content in leaves and roots. Calcium application reduced P but increased Ca content in plant tissues. Increments of Na uptake in nutrient solution resulted in higher Na content in leaves and roots regardless Ca application. These findings suggest that calcium treatment may alleviate the negative impacts of salinity.     

Spinosad resistance development in wild olive fruit fly Bactrocera oleae (Diptera: Tephritidae) populations in California

BACKGROUND: Among target pests of the insecticide spinosad is the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae). In Cyprus, spinosad has been sporadically used since its registration in 2002, whereas in Greece its use has been very limited since its registration in 2004, particularly in biological olive cultivars in Crete. By contrast, in California it has been the only insecticide used against the olive fruit fly since its registration in 2004. This study aimed at examining the resistance status of the olive fruit fly to spinosad. RESULTS: Populations from California, Greece and Cyprus, plus a laboratory population, were tested. Bioassays were performed by oral or topical application of different concentrations of the insecticide. Cypriot populations demonstrated no resistance as compared with that of the laboratory population. Among the Greek populations, only one from Crete demonstrated a fourfold increase in resistance, whereas five populations from California demonstrated a 9–13‐fold increase. CONCLUSION: The observed resistance increase was associated with spinosad applications in the respective areas. These values are relatively low and do not yet pose a serious control problem in the field. However, the observed variation documents that spinosad tolerance has increased in areas where the insecticide has been more extensively used. Copyright © 2010 Society of Chemical Industry     

Incidence and characterisation of resistance to neonicotinoid insecticides and pymetrozine in the greenhouse whitefly,Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae)

BACKGROUND: Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms. Copyright © 2010 Society of Chemical Industry