Production of enniatins A,A1, B,B1, B4, J1 by Fusarium tricinctum in solid corn culture: Structural analysis and effects on mitochondrial respiration

Enniatins (ENs) are secondary fungal metabolites with hexadepsipeptidic chemical structure and they possess a number of potent biological activities that can contaminate several kind of food and foodstuffs increasing the exposure risk for consumers. ENs are produced by several Fusariun strains including Fusarium subglutinans, Fusarium proliferatum and Fusarium tricinctum. Production of a mixture of ENs was performed by culturing F. tricinctum ITEM 9496 on white corn as substrate. The solid culture components were dried and subsequently extracted with water/methanol (50/50 v/v, 0.5% NaCl), homogenised, filtered, extracted by ethyl acetate and analysed by liquid chromatography with diode array detection (LC-DAD). The crude extract was first separated by low pressure liquid chromatography (LPLC) and then further purified by liquid chromatography (LC), resulting in six compounds with a purity higher than 95% as calculated by ¹H NMR, and with a yield of 30–300 mg per compound. The chemical structures of the ENs were determined by liquid chromatography coupled to mass spectrometry (LC–MS) and nuclear magnetic resonance (NMR). The biological activity of the resulting ENs was determined using a mitochondrial respiration test. We discovered that all the ENs studied induced an increase in the mitochondrial respiration resulting in uncoupling of the oxidative phosphorylation. This effect was most likely due to flux of K⁺ ions into the mitochondrial matrix. The order of potency of the ENs derivatives was: A₁ > B₁ > B > A > B₄ > J₁. These results suggest a correlation between the chemical structures and bioactivity and confirm the severe risks for human associated with consumption of enniatins.     

Magnetic Anomalies and Electronic Structure of Ce<Subscript>2</Subscript>Cu<Subscript>2</Subscript>Mg and Ce<Subscript>2</Subscript>Pd<Subscript>2</Subscript>Mg

The intermetallic compounds RE ₂Cu₂Mg and RE ₂Pd₂Mg (RE=La, Ce) were prepared and characterized by magnetic susceptibility and heat-capacity measurements. They crystallize with an ordered U₃Si₂ type structure (space group P4/mbm) and the cerium compounds contain stable trivalent cerium ions, which undergo antiferromagnetic ordering at ∼7.5 and ∼4 K, respectively. In high magnetic fields Ce₂Cu₂Mg exhibits spin reorientation with critical field strength of 40 kOe at 5 K. The data are compared to the non-magnetic isotypic compounds La₂ T ₂Mg (T=Cu, Ni, Pd) and to the already reported intermediate valent Ce₂Ni₂Mg.     

Thermal conductivity of highly crystallized polyethylene

We report thermal conductivity (κ) of low-density, high-density and ultra-high density polyethylene (PE) with different crystallinity and microstructures. PE was crystallized under high-pressure and high-temperature conditions which produce extended chain crystals. By applying a two-phase model, we estimate κ of 100% crystallized PE as a function of pressure and temperature. The increased crystallinity and lamellar thickness (fold length) reduce the thermal resistance, which is reflected not only in the absolute value of κ but also in more pronounced pressure and temperature dependencies approaching those of polycrystalline low-molecular weight materials. The results suggest that it is crucial to increase the lamellar thickness to significantly improve κ of PE with randomly oriented lamellae.     

Sorption Equilibrium in Relation to the Spatial Distribution of Molecules – Application to Desorption of Potato

ABSTRACT

An analysis of desarption isotherms for potato shows the following probable qualities in the water-potato sysarn. in the natural staa the walcr is bound rather strongly due to loss of rotational degrees of freedom in the sorbed molecules, which is caused by small molecular voids in the cellulose structure. This strucmre therefore is formcd as a uniformly cross bound state of the OH-groups. This slate prevails up to a cenin temperature, above which a reaction sas in. whcre OH bonds are successively braken, giving passibility for a panial rotation of sorbed molecules. in the range of lower moisture conlcnt the cellulose strucmre is changed into n crystalline slate a in wood, although the dcgrcc of crystallinity is lower, which is thc     

Non-Destructive Determination of the Structure and Composition of Glazes by Raman Spectroscopy

The utility of Raman spectroscopy as a non-destructive technique for the characterization of glassy (alumino)silicates (modern or ancient glazes and glasses) is demonstrated. The addition of fluxing ions breaks the Si–O linkages and the degree of (de)polymerization determines the relative intensity of the Si–O bending and stretching modes and hence the degree of polymerization could be classified. The analysis can be used to predict the processing temperature of glasses. Bending ( Q ^{' n} ) and stretching ( Qⁿ ) spectral components assigned to isolated ( Q ⁰ or SiO₄), and more or less connected SiO₄ vibrational units with one, two three/four bridging oxygen allow more precise analysis. The method is applied to reference modern porcelain glazes and selected ancient ceramic glazes and glasses, representative of the different production technologies used in the Asian, Islamic, and European worlds from Roman Empire to 19th century.     

Simulation of sea surface wave influence on small target detection with airborne laser depth sounding.

A theoretical model for simulation of airborne depth-sounding lidar is presented with the purpose of analyzing the influence from water surface waves on the ability to detect 1-m(3) targets placed on the sea bottom. Although water clarity is the main limitation, sea surface waves can significantly affect the detectability. The detection probability for a target at a 9-m depth can be above 90% at 1-m/s wind and below 80% at 6-m/s wind for the same water clarity. The simulation model contains both numerical and analytical components. Simulated data are compared with measured data and give realistic results for bottom depths between 3 and 10 m.     

High-end opto ASICs for DVD, data communication receivers and optical distance measurement

The designs with integrated photodiodes and low-noise amplifiers, presented in this paper, reach from DVD pickup units via high-speed glass and plastic fibre receivers to optical distance measurement. Furthermore, new developments in the fields of highly-parallel high-speed receivers for free-space optical interconnect and optical distance measurements are shown.     

A survey of multiple contractions

The AGM theory of belief contraction is extended tomultiple contraction, i.e. to contraction by a set of sentences rather than by a single sentence. There are two major variants: Inpackage contraction all the sentences must be removed from the belief set, whereas inchoice contraction it is sufficient that at least one of them is removed. Constructions of both types of multiple contraction are offered and axiomatically characterized. Neither package nor choice contraction can in general be reduced to contractions by single sentences; in the finite case choice contraction allows for reduction.     

Plastic displacement distributions of the Gaussian white noise excited elasto-plastic oscillator

Slepian model process approximate reasoning is used to obtain representative net and absolute yield displacement processes for the symmetric elasto-plastic oscillator of one degree of freedom excited by stationary Gaussian white noise. Yieldings occur in clumps with yield increments of alternating sign. Distributions are obtained in closed analytical form for the first yielding in a clump, the subsequent yieldings, and the accumulated net and absolute yielding from the entire clump. Moreover distributions of clump durations as well as interclump durations are obtained. All distribution parameters are theoretically calculated, that is, no parameters are obtained from estimation using simulated data. Extensive comparisons with simulated histograms show excellent fits. Also comparisons with published predictions from diffusion theory (Fokker-Planck equation based on the stochastic averaging method) show interesting features and good agreement. Finally an approximate general formula is given for the distribution of the time to the first passage of any given level of net or absolute yielding. This formula is a generalization of a corresponding formula valid for any compound Poisson process of finite second moments.     

Cognitive predictors of incident Alzheimer's disease: A prospective longitudinal study.

The present study examined whether cognitive variables measured at baseline could predict incident cases of Alzheimer's disease (AD) after a 3-year follow-up period. Twenty-six incident AD adults and 179 very old (M?=?83.5 years) adults without dementia participated in a population-based study. Cognitive performance was indexed by the Mini-Mental State Examination (MMSE) and multiple indices of memory and visuospatial and verbal performance. A logistic regression analysis that controlled for age, gender, and education indicated that MMSE scores were reliable indicators of who would develop AD. In addition, recall of organizable words, recognition of faces, and letter fluency were reliable predictors of subsequent dementia status after differences in MMSE performance were partialed out. Thus, although the MMSE is useful in predicting dementia, there is an additional advantage of assessing specific indices of cognitive functioning. Further, supportive episodic memory tasks may be more salient predictors of incident AD than tasks that offer less supportive encoding or retrieval conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)