The hydrographic features of anguillid spawning areas: potential signposts for migrating eels.

Catadromous anguillid eels (Genus Anguilla) migrate from their freshwater or estuarine habitats to marine spawning areas. Evidence from satellite tagging studies indicates that tropical and temperate eel species exhibit pronounced diel vertical migrations between 150 to 300 m nighttime depths to 600 to 800 m during the day. Collections of eggs and larvae of Japanese eels (A. japonica) show they may spawn at these upper nighttime migration depths. How anguillid eels navigate through the ocean and find their spawning areas remains unknown, so this study describes the salinity, temperature and geostrophic currents between 0 and 800 m depths within two confirmed and three hypothetical anguillid spawning areas during likely spawning seasons. Within all four ocean gyres many eels would encounter subducted 'Subtropical Underwater' during their nighttime ascents that could provide odor plumes as signposts. Four spawning areas are located near the western margins of where subducted water masses form cores of elevated salinities (~35.0 to 36.8) around 150 m depths, while one is found near the center of subduction. Low salinity surface waters and fronts are present in some of the areas above the high-salinity cores. Spawning may occur at temperatures between 16 to 24°C where the thermocline locally deepens. At spawning depths, weak westward currents (~0 to 0.1 m s-1) prevail, and eastward surface countercurrents are present. Anguillid eels possess acute sensory capabilities to detect these hydrographic features as potential signposts guiding them to where they spawn.

Does mycorrhization influence herbivore-induced volatile emission in Medicago truncatula?

Symbiosis with mycorrhizal fungi substantially impacts secondary metabolism and defensive traits of colonised plants. In the present study, we investigated the influence of mycorrhization (Glomus intraradices) on inducible indirect defences against herbivores using the model legume Medicago truncatula. Volatile emission by mycorrhizal and non-mycorrhizal plants was measured in reaction to damage inflicted by Spodoptera spp. and compared to the basal levels of volatile emission by plants of two different cultivars. Emitted volatiles were recorded using closed-loop stripping and gas chromatography/mass spectrometry. The documented volatile patterns were evaluated using multidimensional scaling to visualise patterns and stepwise linear discriminant analysis to distinguish volatile blends of plants with distinct physiological status and genetic background. Volatile blends emitted by different cultivars of M. truncatula prove to be clearly distinct, whereas mycorrhization only slightly influenced herbivore-induced volatile emissions. Still, the observed differences were sufficient to create classification rules to distinguish mycorrhizal and non-mycorrhizal plants by the volatiles emitted. Moreover, the effect of mycorrhization turned out to be opposed in the two cultivars examined. Root symbionts thus seem to alter indirect inducible defences of M. truncatula against insect herbivores. The impact of this effect strongly depends on the genetic background of the plant and, hence, in part explains the highly contradictory results on tripartite interactions gathered to date.

Microbial oligosaccharides differentially induce volatiles and signalling components in Medicago truncatula.

Plants perceive biotic stimuli by recognising a multitude of different signalling compounds originating from the interacting organisms. Some of these substances represent pathogen-associated molecular patterns, which act as general elicitors of defence reactions. But also beneficial microorganisms like rhizobia take advantage of compounds structurally related to certain elicitors, i.e. Nod-factors, to communicate their presence to the host plant. In a bioassay-based study we aimed to determine to what extent distinct oligosaccharidic signals are able to elicit overlapping responses, including the emission of volatile organic compounds which is mainly considered a typical mode of inducible indirect defence against herbivores. The model legume Medicago truncatula Gaertn. was challenged with pathogen elicitors (beta-(1,3)-beta-(1,6)-glucans and N,N',N'',N'''-tetraacetylchitotetraose) and two Nod-factors, with one of them being able to induce a nodulation response in M. truncatula. Single oligosaccharidic elicitors caused the emission of volatile organic compounds, mainly sesquiterpenoids. The volatile blends detected were quite characteristic for the applied compounds, which could be pinpointed by multivariate statistical methods. As potential mediators of this response, the levels of jasmonic acid and salicylic acid were determined. Strikingly, neither of these phytohormones exhibited changing levels correlating with enhanced volatile emission. All stimuli tested caused an overproduction of reactive oxygen species, whereas nitric oxide accumulation was only effected by elicitors that were equally able to induce volatile emission. Thus, all signalling compounds tested elicited distinct reaction patterns. However, similarities between defence reactions induced by herbivory and pathogen-derived elicitors could be ascertained; but also Nod-factors were able to trigger defence-related reactions.

Changes in the pattern of substance abuse after the onset of psychosis.

OBJECTIVE: The aim of this study was to examine early signs of psychosis in patients suffering from both drug dependence and schizophrenia, compared to a control group of drug-addicted patients without a comorbid psychotic disorder, and to assess whether the presence of these signs was related to changes in the pattern of substance abuse. METHOD: In a rehabilitation hospital for young addicts, 32 patients with a comorbid diagnosis of schizophrenia and 30 patients without the diagnosis of a psychotic disorder, were assessed using the Interview for the Retrospective Assessment of the Onset of Schizophrenia. Information relating to 64 signs of early psychosis was collected from every patient. From the 64 signs, five groups of symptoms were defined: non-specific and precursor symptoms; non-specific and depressive symptoms; negative symptoms; positive symptoms; and impaired social adjustment. The semiquantitative pattern of substance abuse for each 1-year interval over the previous 10 years was investigated using the categories of chapter F1 of ICD-10 and including an additional category "biological drugs". The relationship between the pattern of substance abuse and the presence of early signs was assessed using anova and non-parametric statistical methods. RESULTS: The results indicate that the defined pathological symptomatology greatly influences the pattern of consumption of psychoactive substances in both the psychosis group and the control group. The group factor exerted the greatest influence within the categories "biological drugs" and "other stimulants", where the "psychosis and addiction group" consumed significantly more than the control group. CONCLUSIONS: There is a subgroup of non-psychotic addicted patients whose pattern of psychoactive substance abuse is similar to that found in addicted patients suffering from schizophrenia. It may be helpful to systematically identify this subgroup with regard to possible therapeutic implications, particularly with regard to possible pharmacological treatment options.

Isospin violation in e+ e- -->BB.

The ratio of the B+ B- and B0B0 production rates in e+ e- annihilation is computed as a function of the B meson velocity and BB*pi coupling constant, using a nonrelativistic effective field theory.

Improved Syntheses and Some Selective Transformations of 2,2,4,4-Tetrachloro-8-oxabicyclo[3.2.1]oct-6-en-3-ones.

The methyl- and alkenyl-substituted furans 1b-h react with pentachloroacetone (2) and sodium 2,2,2-trifluoroethoxide solution to form the title compounds 3b-h in good yield. With the furans 1i-m bearing an oxygen or a sulfur heteroatom in the side chain, moderate yields are obtained. Dechlorination of the [4+3] cycloadducts 3 with the Zn-Cu couple leads to the corresponding oxabicyclic ketones 4. On catalytic hydrogenation of the tetrachlorooxabicyclooctenones 3a-c hydrogenolysis of the exo-carbon-chlorine bonds occurs, leading to the endo-2,endo-4-dichloro-8-oxabicyclooctan-3-ones 8a-c. With lithium aluminum hydride and Grignard reagents, 8a and 3a form the endo-3-alcohols 12a-c and 13, respectively, the latter with uncertain configuration at C-3, in a highly stereoselective manner. The ether bridge in the dechlorinated oxabicyclooctenones 4b, 4f, and 4g can be cleaved by means of trimethylsilyl triflate/triethylamine to produce the tropones 5b, 5f, and 5g. Hydrogenation of 1,5-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (4c), followed by Wolff-Kishner reduction, affords 1,5-dimethyl-8-oxabicyclo[3.2.1]octane (7). m-Chloroperbenzoic acid epoxidizes the alkenyl side chain of the tetrachlorinated oxabicycles 3d, 3e, 3g, and 3h in a site-selective reaction. In contrast, from the dehalogenated oxabicyclic ketone 4g the bis(epoxide) 14 is obtained.