Enzymatic modification of trilinolein: Incorporation of n-3 polyunsaturated fatty acids

Two immobilized lipases, IM60 fromMucor miehei and SP435 fromCandida antarctica, were used as biocatalysts for the modification of trilinolein with n-3 polyunsaturated fatty acids (PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), by using their ethyl esters as acyl donors (EEPA and EDHA, respectively). Transesterification (ester-ester interchange) reactions were carried out in organic solvent. The products were analyzed according to their equivalent carbon number and polarity by reverse-phase high-performance liquid chromatography, and the fatty acid profiles were determined by gas-liquid chromatography. Modified triacylglycerol products contained 1 or 2 molecules of n-3 PUFA. With EEPA as the acyl donor, the total EPA product yields with IM60 and SP435 as biocatalysts were 79.6 and 81.4%, respectively. However, with EDHA as the acyl donor and IM60 and SP435 as biocatalysts, the total DHA product yields were 70.5 and 79.7%, respectively. Effects of reaction parameters, such as type of solvent, enzyme load, time course, and molar ratio of substrates on the n-3 PUFA incorporation, were followed with SP435 as the biocatalyst. High yields were obtained, even in the absence of organic solvent. These lipids do hold promise for specialty nutrition and other therapeutic uses.     

In-situ sampling and separation of RNA from individual mammalian cells

In this investigation RNA was directly sampled and separated at the single-cell level (without extraction) by capillary electrophoresis (CE). Laser-induced fluorescence (LIF) was employed to detect ethidium bromide-labeled RNA molecules under native conditions. Hydroxypropylmethylcellulose was used as a matrix for molecular sieving. Additives to the polymer solution included poly(vinylpyrrolidone) to eliminate the electroosmotic flow and mannitol to enhance the separation. Peak identities were confirmed as RNA by enzymatic treatment with RNase I. The individual Chinese Hamster Ovary (CHO-K1) cells were injected into a capillary and the cells were lysed online with sodium dodecyl sulfate (SDS) solutions before running electrophoresis. Low molecular mass (LMM) RNAs as well as larger fragments (tentatively identified as 18S and 28S ribosomal RNA by comparison with the literature) were detected with this system, which corresponds to a detected amount of approximately equals 10-20 pg of RNA/cell. A Proteinase K study showed that proteins incorporated with RNA molecules were eliminated by SDS treatment and thus did not influence the migration of RNA. Experiments were also performed with this technique to detect nucleic acid damage. Changes in the peak pattern were detected in the cells treated with hydrogen peroxide, which meant that strand breaks occurred in DNA and RNA. It was found that 60 mM caused the most severe damage to the nucleic acids.     

Children's understanding of the knowledge prerequisites of drawing and pretending.

Many young children will claim that someone is pretending to be something even when the person does not know what that something is. To examine whether children's failure to take knowledge prerequisites into account is part of a more fundamental problem in recognizing how mental representations constrain external ones, the authors asked children whether an artist who did not know what something was, yet whose drawing bore resemblance to it, was drawing it. The same questions were asked regarding pretending. Children performed similarly on pretending and drawing questions, and performance on both questions improved when the protagonists' point of view was emphasized. Performance for drawing improved somewhat when alternative goals were stated. Further, cross-sectional data indicated that understanding how knowledge relates to producing external representations increases gradually from age 4 to age 8, suggesting that experiential factors may be crucial to this understanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ethnopsychologies: Cultural variations in theories of mind.

A set of basic beliefs about others' minds and behavior, referred to as folk psychology or theory of mind, is often discussed as if it were the same the world over. Yet, certainly variation in folk psychology exists. This article compares several aspects of European American theory of mind with other cultural models, as suggested by experiments and ethnographies, with the purpose of illuminating the degree to which there is variation. After summarizing 4 types of variation, the author explores possible sources of variability, implications for the mindreading process, potential universals, and directions for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The rapid separation of aflatoxins on silica gel coated glass cylinders

A chromatographic method is described for the separation of aflatoxins on silica gel coated glass cylinders prepared with a chloroformacetone slurry. This can be done in 35–40 min compared with more than 2 hr for thin layer chromatography (TLC). This method is more rapid, economical and its sensitivity is comparable to TLC. University of Georgia College of Agriculture Experiment Stations, Journal Series Paper Number 643, College Station, Athens, Ga.     

Mechanisms for induction of acquired host immunity by neutrophil peptide defensins

Human neutrophil peptide (HNP) defensins were studied to determine their potential effects on adaptive mucosal immunity. Intranasal delivery of HNPs plus ovalbumin (OVA) enhanced OVA-specific serum IgG antibody (Ab) responses. However, OVA-specific IgA Abs were not induced in mucosal secretions or in serum. CD4(+) T cells of intranasally immunized mice displayed higher OVA-specific proliferative responses and elevated production of interferon gamma, interleukin (IL) 5, IL-6, and IL-10 when compared with control groups receiving OVA alone. In vitro, HNPs also enhanced both proliferative responses and T helper (Th) cytokine secretion profiles of CD3epsilon-stimulated spleen- and Peyer's patch-derived naive CD4(+) T cells. HNPs modulated the expression of costimulatory molecules by lipopolysaccharide- or CD3epsilon-stimulated splenic and Peyer's patch B or T cell populations, respectively. These studies show that defensins enhance systemic IgG, but not IgA, Ab responses through help provided by CD4(+) Th1- and Th2-type cytokines and foster B and T cell interactions to link innate immunity with the adaptive immune system.     

The corrosion of materials in spallation neutron sources

Efforts to measure the real-time corrosion rates of alloy 718 during 800 MeV proton radiation at currents up to 1 mA are reported. Specially designed corrosion probes, which incorporate ceramic seals, were mounted in a water manifold that allowed samples to be directly exposed to the proton beam at the Los Alamos Neutron Science Center. The water system that supplied the manifold provided a means for controlling water chemistry, measuring dissolved hydrogen concentration, and measuring the effects of water radiolysis and water quality on corrosion rate. Real-time corrosion rate measurements during proton irradiation showed an exponential increase in corrosion rate with proton-beam current. These results are discussed within the context of water radiolysis at the diffusion boundary layer/beam-spot interface. However, additional factors that may influence these parameters, such as oxide spallation and charge build-up in the passive film, are not ruled out. Scott Lillard earned his Ph.D. in materials science and engineering from Johns Hopkins University in 1992. He is currently a technical staff member at the Materials Corrosion and Environmental Effects Laboratory, Los Alamos National Laboratory. Darryl P. Butt earned his Ph.D. in ceramic science from Pennsylvania State University in 1991. He is currently a technical staff member at the Non-Proliferation and International Security Division, Los Alamos National Laboratory.     

Electrophoretic profiling of both RNA and protein from a single 250-pL sample

A novel approach is described that uses capillary electrophoresis (CE) to electrophoretically sample and separate both protein and RNA from a single injected plug of cell lysate. A 250-pL sample of lysate from Chinese hamster ovary cells (9.6 x 10(7) cells/mL) was hydrodynamically injected into a capillary containing a Tris-based aqueous buffer. This was followed by selective electrokinetic ejection of RNA from the lysate into water, yielding an effective cell concentration of RNA of 3000 cells/mL. The cellular components (e.g., proteins) retained in the capillary were separated and then detected with laser-induced fluorescence (LIF) using 275-nm excitation. The ejected/diluted sample was subsequently injected into a separate CE-LIF system, which utilized an entangled polymer sieving matrix and 543-nm excitation for the detection of ethidium bromide-labeled nucleic acids (i.e., RNA). Virtually no sample preparation is required other than simple washing and lysing of the cells isolated from culture. This combined approach can be easily modified for the detection of any analyte through adjustment of CE-HF conditions. In addition, it provides an effective method for desalting cellular RNA samples having complex matrixes, which results in improved RNA injection efficiency and a 7600-fold effective signal enhancement over total lysate injection.