Production of aflatoxins on amaranth seeds by Aspergillus spp.

Five varieties of amaranth seeds, cooked and uncooked, were inoculated with toxigenic strains of Aspergillus spp. and the levels of aflatoxins were quantitated. Cooking seeds prior to inoculation increased the level of aflatoxins; aflatoxin levels were the same in all the amaranth varieties inoculated. Aflatoxin level was much lower on amaranth than on rice, corn or winged bean.     

Room temperature electroabsorption in a GexSi1-x PIN photodiode

We present room temperature electroabsorption measurements in a Ge _0.2Si_0.8 pin photodiode. The results appear to be very similar to those reported earlier on Ge_xSi_1-x/Si multiple quantum wells     

Plasma somatotropin and prolactin concentrations in young dairy sires before and after a 24-hour fast

To examine the efficacy of plasma concentrations of bST or prolactin as predictors of expected daughter performance, blood samples were collected from young Holstein sires. Blood samples were collected at 15-min intervals via jugular cannulas from 1000 until 1600 h (d 1), beginning 4 h after morning hay feeding. Bulls were not fed again until after collection of blood samples on d 2. Samples were collected at 15-min intervals from 1000 until 1300 h on d 2. Peak values and frequency of hormonal secretory patterns of each bull were characterized by an iterative process in which values greater than 2 SD from the mean were flagged as peaks and excluded from the subsequent calculation of SD and mean. The process continued until an iteration in which no new peaks were flagged. Imposition of a 24-h fast did not alter mean basal bST or prolactin concentrations, but reduced mean peak and overall concentrations of both hormones. The number of bST peaks on d 1 was inversely related to both USDA and Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and both USDA and Northeast Artificial Insemination Sire Comparison sire PD for milk yield, but was positively correlated on d 2 with USDA Pedigree Index for milk yield. Mean peak bST on d 2 was correlated with Northeast Artificial Insemination Sire Comparison Estimated Breeding Value for fat yield and sire USDA PD for fat yield. Prolactin peak frequency on d 1 was negatively related to Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and sire PD for fat yield. Difference between mean prolactin on d 1 and 2 was negatively related to Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and Estimated Breeding Value for fat yield. Endocrine parameters in young sires may be related to genetic merit for production parameters.     

Neurotransmitter activation of inwardly rectifying potassium current in dissociated hippocampal CA3 neurons: interactions among multiple receptors

We characterized potassium current activated by G-protein-coupled receptors in acutely dissociated hippocampal CA3 neurons. Agonists for serotonin, adenosine, and somatostatin receptors reliably activated a potassium-selective conductance that was inwardly rectifying and that was blocked by 1 mM external Ba2+. The conductance had identical properties to that activated by GABAB receptors in the same cells. In one-half of the CA3 neurons that were tested, the metabotropic glutamate agonist 1S,3R-ACPD also activated inwardly rectifying Ba2+-sensitive potassium current. Activation of the current by serotonin and adenosine agonists occurred with a time constant of 200-700 msec after a lag of 50-100 msec; on removal of agonist the current deactivated with a time constant of 1-2 sec after a lag of 200-400 msec. These kinetics are similar to GABAB-activated current and consistent with a direct action of G-protein on the channels. For somatostatin, both activation and deactivation were approximately fourfold slower, probably limited by agonist binding and unbinding. The half-maximally effective agonist concentrations were approximately 75 nM for somatostatin, approximately 100 nM for serotonin, and approximately 400 nM for 2-chloroadenosine. Dose-response relationships had Hill coefficients of 1.2-1.9, suggesting cooperativity in the receptor-to-channel coupling mechanism. At saturating concentrations of agonists, the combined application of baclofen and either somatostatin, serotonin, or 2-chloroadenosine produced effects that were subadditive and often completely occlusive. However, at subsaturating concentrations the effects of baclofen and 2-chloroadenosine were supra-additive. Thus, low levels of different transmitters can act synergistically in activating inwardly rectifying potassium current.     

Inhibitory effect of ginsenosides from ginseng leaves and flowers on the LPS-stimulated IL-12 production in bone marrow-derived dendritic cells

Ginseng leaves and flowers have been known to be rich in various ginsenosides. The aim of present study is to screen the effect of 34 ginsenosides from ginseng leaves and flowers on interlukin (IL)-12 production in bone marrow-derived dendritic cells induced by lipopolysaccharide (LPS). Noticeably, floralginsenoside Kc (5), floralginsenoside J (26), and ginsenoside I (33) exhibited particularly inhibitory effect on LPS-induced IL-12 production with IC₅₀ values of 16.3, 25.8, and 6.7 μM, respectively. In addition, floralginsenoside Kc (5) suppressed significantly LPS-stimulated IL-6 and tumor necrosis factor-α (TNF-α) production. These results warrant further studies concerning potential of saponin extracts of Panax ginseng leaves and flowers for medicinal foods.     

Function of cryopreserved human effector cells in antibody-dependent, cell-mediated cytotoxicity

Cells active in an ADCC model were studied for their ability to withstand cryopreservation. For this model, we used the [3H]proline microcytotoxicity assay with fibroblast target cells and a serum containing lymphocyte-dependent antibody reactive with the alloantigens on those target cells. Human blood effector cells active in this system can be successfully cryopreserved with minor dimunition in function with standard techniques and concentrations between 9 and 12% DMSO.