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11.
Amelia P. Guevara Carolyn Vargas Hiromu Sakurai Yasuhiro Fujiwara Keiji Hashimoto Takashi Maoka Mutzuo Kozuka Yoshohiro Ito Harukuni Tokuda Hoyoku Nishino 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》1999,440(2):1270
In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(α-
-rhamnosyloxy)benzyl carbamate (1) together with seven known compounds, 4(α-
-rhamnosyloxy)-benzyl isothiocyanate (2), niazimicin (3), niazirin (4), β-sitosterol (5), glycerol-1-(9-octadecanoate) (6), 3-O-(6′-O-oleoyl-β-
-glucopyranosyl)-β-sitosterol (7), and β-sitosterol-3-O-β-
-glucopyranoside (8). Four of the isolates (2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein–Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin (3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin (3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis. 相似文献
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Juan Felipe Escobar Juan Jairo Vaca-González Johana Maria Guevara Jose Félix Vega Yoshie Adriana Hata Diego Alexander Garzón-Alvarado 《Bioelectromagnetics》2020,41(1):41-51
Magnetic fields (MFs) have been used as an external stimulus to increase cell proliferation in chondrocytes and extracellular matrix (ECM) synthesis of articular cartilage. However, previously published studies have not shown that MFs are homogeneous through cell culture systems. In addition, variables such as stimulation times and MF intensities have not been standardized to obtain the best cellular proliferative rate or an increase in molecular synthesis of ECM. In this work, a stimulation device, which produces homogeneous MFs to stimulate cell culture surfaces was designed and manufactured using a computational model. Furthermore, an in vitro culture of primary rat chondrocytes was established and stimulated with two MF schemes to measure both proliferation and ECM synthesis. The best proliferation rate was obtained with an MF of 2 mT applied for 3 h, every 6 h for 8 days. In addition, the increase in the synthesis of glycosaminoglycans was statistically significant when cells were stimulated with an MF of 2 mT applied for 5 h, every 6 h for 8 days. These findings suggest that a stimulation with MFs is a promising tool that could be used to improve in vitro treatments such as autologous chondrocyte implantation, either to increase cell proliferation or stimulate molecular synthesis. Bioelectromagnetics. 2020;41:41–51 © 2019 Bioelectromagnetics Society 相似文献
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Enrique Sáez-Laguna María-ángeles Guevara Luis-Manuel Díaz David Sánchez-Gómez Carmen Collada Ismael Aranda María-Teresa Cervera 《PloS one》2014,9(8)
There is an increasing interest in understanding the role of epigenetic variability in forest species and how it may contribute to their rapid adaptation to changing environments. In this study we have conducted a genome-wide analysis of cytosine methylation pattern in Pinus pinea, a species characterized by very low levels of genetic variation and a remarkable degree of phenotypic plasticity. DNA methylation profiles of different vegetatively propagated trees from representative natural Spanish populations of P. pinea were analyzed with the Methylation Sensitive Amplified Polymorphism (MSAP) technique. A high degree of cytosine methylation was detected (64.36% of all scored DNA fragments). Furthermore, high levels of epigenetic variation were observed among the studied individuals. This high epigenetic variation found in P. pinea contrasted with the lack of genetic variation based on Amplified Fragment Length Polymorphism (AFLP) data. In this manner, variable epigenetic markers clearly discriminate individuals and differentiates two well represented populations while the lack of genetic variation revealed with the AFLP markers fail to differentiate at both, individual or population levels. In addition, the use of different replicated trees allowed identifying common polymorphic methylation sensitive MSAP markers among replicates of a given propagated tree. This set of MSAPs allowed discrimination of the 70% of the analyzed trees. 相似文献
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Because of the magnitude of land use currently occurring in tropical regions, the local loss of animal species due to habitat fragmentation has been widely studied, particularly in the case of vertebrates. Many invertebrate groups and the ichneumonid wasps in particular, however, have been poorly studied in this context, despite the fact that they are one of the most species-rich groups and play an important role as regulators of other insect populations. Here, we recorded the taxonomic composition of ichneumonid parasitoids and assessed their species richness, abundance, similarity, and dominance in the Los Tuxtlas tropical rain forest, Mexico. We compared two forest types: a continuous forest (640 ha) and a forest fragment (19 ha). We sampled ichneumonids using four malaise traps in both forest types during the dry (September–October) and rainy (March–April) seasons. A total of 104 individuals of Ichneumonidae belonging to 11 subfamilies, 18 genera, and 42 species were collected in the continuous forest and 11 subfamilies, 15 genera, and 24 species were collected in the forest fragment. Species richness, abundance, and diversity of ichneumonids were greater in the continuous forest than in the forest fragment. We did not detect differences between seasons. Species rank/abundance curves showed that the ichneumonid community between the forest types was different. Species similarity between forest types was low. The most dominant species in continuous forest was Neotheronia sp., whereas in the forest fragment, it was Orthocentrus sp. Changes in the ichneumonid wasp community may compromise important tropical ecosystem processes. 相似文献
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Krogh-Madsen T Schaffer P Skriver AD Taylor LK Pelzmann B Koidl B Guevara MR 《American journal of physiology. Heart and circulatory physiology》2005,289(1):H398-H413
We recorded transmembrane potential in whole cell recording mode from small clusters (2-4 cells) of spontaneously beating 7-day embryonic chick ventricular cells after 1-3 days in culture and investigated effects of the blockers D-600, diltiazem, almokalant, and Ba2+. Electrical activity in small clusters is very different from that in reaggregates of several hundred embryonic chick ventricular cells, e.g., TTX-sensitive fast upstrokes in reaggregates vs. TTX-insensitive slow upstrokes in small clusters (maximum upstroke velocity approximately 100 V/s vs. approximately 10 V/s). On the basis of our voltage- and current-clamp results and data from the literature, we formulated a Hodgkin-Huxley-type ionic model for the electrical activity in these small clusters. The model contains a Ca2+ current (ICa), three K+ currents (IKs, IKr, and IK1), a background current, and a seal-leak current. ICa generates the slow upstroke, whereas IKs, IKr, and IK1 contribute to repolarization. All the currents contribute to spontaneous diastolic depolarization, e.g., removal of the seal-leak current increases the interbeat interval from 392 to 535 ms. The model replicates the spontaneous activity in the clusters as well as the experimental results of application of blockers. Bifurcation analysis and simulations with the model predict that annihilation and single-pulse triggering should occur with partial block of ICa. Embryonic chick ventricular cells have been used as an experimental model to investigate various aspects of spontaneous beating of cardiac cells, e.g., mutual synchronization, regularity of beating, and spontaneous initiation and termination of reentrant rhythms; our model allows investigation of these topics through numerical simulation. 相似文献
19.
Early development and Juvenile Culture Technique of Speckled Flounder,Paralichthys woolmani (Jordan & Williams, 1897) under ambient seawater 下载免费PDF全文
M. Bohórquez‐Cruz S. Rodríguez S. Sonnenholzner W. Argüello‐Guevara 《Zeitschrift fur angewandte Ichthyologie》2018,34(3):610-616
The speckled flounder Paralichthys woolmani is a flatfish species found in Ecuadorian coastal waters, consumed by local coastal communities and likely an excellent candidate for aquaculture production in indoor facilities. This study describes the early development and culture technique of P. woolmani under experimental conditions. Broodstocks were obtained from the wild and kept under laboratory conditions for this study. A total of four effective spontaneous spawns were registered at water temperature of 24.1°C, resulting in 1.3 million eggs and 129.2 thousand newly hatched larvae. Larval pelagic life lasted 28 days post hatch. Survival at benthic juvenile stage ranged 0.3%–46.9%. Pseudoalbinism was present in all juvenile batches. However, different pigmentation patterns in juveniles were recovered with addition of semi‐moist diet. There was no presence of ectoparasites or abnormal eye migration. At 370 days post hatch, flatfish reached 294.6 ± 86.9 g of body weight. These results can be of practical use for optimizing culture conditions to increase the yield of P. woolmani in captivity. 相似文献