8,424 research outputs found
Effects of phytoestrogen on sexual development
Phytoestrogen is an estrogenic compound that occurs naturally in plants. The most common sources of phytoestrogen are soybean products, which contain high levels of isoflavones. This compound, which has structural similarity with estrogen, can act as an estrogen receptor agonist or antagonist. Animal studies provide evidence of the significant effects of phytoestrogen on sexual development, including altered pubertal timing, impaired estrous cycling and ovarian function, and altered hypothalamus and pituitary functions. Although human studies examining the effects of phytoestrogen on sexual development are extremely limited, the results of some studies agree with those of the animal studies. In this paper, we review the possible mechanism of phytoestrogen action and the evidence showing the effects of phytoestrogen on sexual development in animal and human studies
Growth of superconducting MgB2 thin films via postannealing techniques
We report the effect of annealing on the superconductivity of MgB2 thin films
as functions of the postannealing temperature in the range from 700 C to 950 C
and of the postannealing time in the range from 30 min to 120 min. On annealing
at 900 C for 30 min, we obtained the best-quality MgB2 films with a transition
temperature of 39 K and a critical current density of ~ 10^7 A/cm^2. Using the
scanning electron microscopy, we also investigated the film growth mechanism.
The samples annealed at higher temperatures showed the larger grain sizes,
well-aligned crystal structures with preferential orientations along the
c-axis, and smooth surface morphologies. However, a longer annealing time
prevented the alignment of grains and reduced the superconductivity, indicating
a strong interfacial reaction between the substrate and the MgB2 film.Comment: 7 pages, 4 figures include
Galatheoid squat lobsters (Crustacea: Decapoda: Anomura) from Korean waters
Abstract Ten species of Galatheoidea (squat lobsters), belonging to two families, were collected in the Korean exclusive economic zone: Galathea balssi Miyake and Baba, 1964, Galathea orientalis Stimpson, 1858, Galathea pubescens Stimpson, 1858, and Galathea rubromaculata Miyake and Baba, 1967 belonging to Galatheidae; Bathymunida brevirostris Yokoya, 1933, Cervimunida princeps Benedict, 1902, Munida caesura Macpherson and Baba, 1993, Munida japonica Stimpson, 1858, Munida pherusa Macpherson and Baba, 1993, and Paramunida scabra (Henderson, 1885) belonging to Munididae. The present study comprises the morphological description of these ten species, including drawings and color photographs, a brief review of their regional records, and a key for their identification. Although all species are common in Japanese waters, G. balssi, G. rubromaculata, B. brevirostris, C. princeps, M. caesura, and M. pherusa are new to Korean marine fauna
Ginsenoside Compound K Induces Ros-Mediated Apoptosis and Autophagic Inhibition in Human Neuroblastoma Cells In Vitro and In Vivo
Autophagy can result in cellular adaptation, as well as cell survival or cell death. Modulation of autophagy is increasingly regarded as a promising cancer therapeutic approach. Ginsenoside compound K (CK), an active metabolite of ginsenosides isolated from Panax ginseng C.A. Meyer, has been identified to inhibit growth of cancer cell lines. However, the molecular mechanisms of CK effects on autophagy and neuroblastoma cell death have not yet been investigated. In the present study, CK inhibited neuroblastoma cell proliferation in vitro and in vivo. Treatment by CK also induced the accumulation of sub-G1 population, and caspase-dependent apoptosis in neuroblastoma cells. In addition, CK promotes autophagosome accumulation by inducing early-stage autophagy but inhibits autophagic flux by blocking of autophagosome and lysosome fusion, the step of late-stage autophagy. This effect of CK appears to be mediated through the induction of intracellular reactive oxygen species (ROS) and mitochondria membrane potential loss. Moreover, chloroquine, an autophagy flux inhibitor, further promoted CK-induced apoptosis, mitochondrial ROS induction, and mitochondria damage. Interestingly, those promoted phenomena were rescued by co-treatment with a ROS scavenging agent and an autophagy inducer. Taken together, our findings suggest that ginsenoside CK induced ROS-mediated apoptosis and autophagic flux inhibition, and the combination of CK with chloroquine, a pharmacological inhibitor of autophagy, may be a novel therapeutic potential for the treatment of neuroblastoma
Heterologous expression of a tannic acid-inducible laccase3 of Cryphonectria parasitica in Saccharomyces cerevisiae
<p>Abstract</p> <p>Background</p> <p>A tannic acid-inducible and mycoviral-regulated laccase3 (<it>lac</it>3) from the chestnut blight fungus <it>Cryphonectria parasitica </it>has recently been identified, but further characterization was hampered because of the precipitation of protein products by tannic acid supplementation. The present study investigated the heterologous expression of the functional laccase3 using a yeast <it>Saccharomyces cerevisiae</it>.</p> <p>Results</p> <p>Laccase activity in the culture broth of transformants measured using a laccase-specific substrate suggested that the <it>lac</it>3 gene was successfully expressed and the corresponding protein product secreted into the culture media. In addition, activity staining and Western blot analysis of a native gel revealed that the enzyme activity co-existed with the protein product specific to anti-laccase3 antibody, confirming that the cloned <it>lac</it>3 gene is responsible for the laccase activity. When transformants were grown on plates containing tannic acid-supplemented media, brown coloration was observed around transformed cells, indicating the oxidation of tannic acid. However, the enzymatic activity was measurable only in the selective ura<sup>- </sup>media and was negligible in nonselective nutrient-rich culture conditions. This was in part because of the increased plasmid instability in the nonselective media. Moreover, the protein product of <it>lac</it>3 appears to be sensitive to the cultured nonselective nutrient-rich broth, because a rapid decline in enzymatic activity was observed when the cultured broth of ura<sup>- </sup>media was mixed with that of nonselective nutrient-rich broth. In addition, constitutive expression of the <it>lac</it>3 gene resulted in a reduced cell number of the <it>lac</it>3 transformants compared to that of vector-only transformed control. However, the presence of recombinant vector without <it>lac</it>3 induction did not affect the growth of transformants.</p> <p>Conclusions</p> <p>The results suggest that expression of the <it>lac</it>3 gene has an inhibitory effect on the growth of transformed <it>S. cerevisiae </it>and that the controlled expression of <it>lac</it>3 is appropriate for the possible application of recombinant yeast to the treatment of phenolic compounds.</p
TCTAP A-165 Comparison in Cardiac Remodeling Between Surgical Treatment and Device Closure of Atrial Septal Defect
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