273 research outputs found

    Asexual reproduction strategies in the moon jellyfish Aurelia (Cnidaria: Scyphozoa)

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    The genus Aurelia is one of the major contributors to jellyfish blooms in coastal waters, possibly due to its adaptive reproduction strategies. Different Aurelia lineages have adapted their reproduction modes to varying environmental conditions in their respective habitats. To understand the successful adaptation strategies, three strains of Aurelia coerulea and two strains of Aurelia solida polyps from different geographical areas were exposed to a range of temperatures and two food regimes, and the effects on reproduction rates were assessed. Asexual reproduction was significantly affected by the changes in these factors. The highest reproduction rate under sufficient food conditions was observed in the United States strain and the lowest was observed in the Israel strain, regardless of temperature, indicating the differences in the blooming potential. Six asexual reproduction modes were observed, of which lateral budding, lateral budding by means of stolons, and reproduction from parts of stolons were the main modes used by all Aurelia strains, except Aurelia solidaISR, for which reproduction by stolons was the main mode. The capability to switch reproductive strategies in response to environmental cues depending on the lineage predetermines the highly frequent blooming events of Aurelia.Fil: Wang, Fanghan. Chinese Academy of Sciences; República de ChinaFil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Xu, Shengnan. Chinese Academy of Sciences; República de ChinaFil: Ma, Yuanqing. Shandong Marine Resource And Environment Research Institute; ChinaFil: Sun, Tingting. Chinese Academy of Sciences; República de ChinaFil: Wang, Lei. Chinese Academy of Sciences; República de ChinaFil: Zhao, Jianmin. Chinese Academy of Sciences; República de ChinaFil: Dong, Zhijun. Chinese Academy of Sciences; República de Chin

    Effects of Chitosan on Body Weight Gain, Growth Hormone and Intestinal Morphology in Weaned Pigs

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    The study was conducted to determine the effects of chitosan on the concentrations of GH and IGF-I in serum and small intestinal morphological structure of piglets, in order to evaluate the regulating action of chitosan on weaned pig growth through endocrine and intestinal morphological approaches. A total of 180 weaned pigs (35 d of age; 11.56±1.61 kg of body weight) were selected and assigned randomly to 5 dietary treatments, including 1 basal diet (control) and 4 diets with chitosan supplementation (100, 500, 1,000 and 2,000 mg/kg, respectively). Each treatment contained six replicate pens with six pigs per pen. The experiment lasted for 28 d. The results showed that the average body weight gain (BWG) of pigs was improved quadratically by dietary chitosan during the former 14 d and the later 14 d after weaned (p<0.05). Furthermore, dietary supplementation of chitosan tended to quadratically increase the concentration of serum GH on d 14 (p = 0.082) and 28 (p = 0.087). Diets supplemented with increasing levels of chitosan increased quadratically the villus height of jejunum and ileum on d 14 (p = 0.089, p<0.01) and 28 (p = 0.074, p<0.01), meanwhile, chitosan increased quadratically the ratio of villus height to crypt depth in duodenum, jejunum and ileum on d 14 (p<0.05, p = 0.055, p<0.01) and 28 (p<0.01, p<0.01, p<0.01), however, it decreased quadratically crypt depth in ileum on d 14 (p<0.05) and that in duodenum, jejunum and ileum on d 28 (p<0.01, p<0.05, p<0.05). In conclusion, these results indicated that chitosan could quadratically improve growth in weaned pigs, and the underlying mechanism may due to the increase of the serum GH concentration and improvement of the small intestines morphological structure

    The Motion of An Inv Nodal Cilium: a Realistic Model Revealing Dynein-Driven Ciliary Motion with Microtubule Mislocalization

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    Background/Aims: Nodal cilia that rotate in the ventral node play an important role in establishing left-right asymmetry during embryogenesis; however, inv mutant cilia present abnormal movement and induce laterality defects. The mechanism of their motility, which is regulated by dynein activation and microtubule arrangement, has not been fully understood. This study analyzed the dynein-triggered ciliary motion in the abnormal ultrastructure of the inv mutant, aiming to quantitatively evaluate the influence of microtubule mislocalization on the movement of the cilium. Methods: We established a realistic 3-D model of an inv mutant cilium with an ultrastructure based on tomographic datasets generated by ultra-high voltage electron microscopy. The time-variant activation of the axonemal dynein force was simulated by pairs of point loads and embedded at dynein-mounted positions between adjacent microtubule doublets in this mathematical model. Utilizing the finite element method and deformable grid, the motility of the mutant cilium that is induced by various dynein activation hypotheses was investigated and compared to experimental observation. Results: The results indicate that for the inv mutant, simulations of the ciliary movement with the engagement of dyneins based on the distance-controlled pattern in the partially activation scenario are broadly consistent with the observation; the shortening of the microtubules induces smaller movement amplitudes, while the angles of the mislocalized microtubules affect the pattern of the ciliary movement, and during the ciliary movement, the microtubules swing and twist in the mutant ciliary body. Conclusion: More generally, this study implies that dynein engagement is sensitive to subtle geometric changes in the axoneme, and thus, this geometry greatly influences the integrity of a well-formed ciliary rotation

    Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

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    We transplanted kidneys from α1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GalT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GalT-KO pigs to humans. © 2005 Nature Publishing Group

    Evaluating the Cellular Targets of Anti-4-1BB Agonist Antibody during Immunotherapy of a Pre-Established Tumor in Mice

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    Manipulation of the immune system represents a promising avenue for cancer therapy. Rational advances in immunotherapy of cancer will require an understanding of the precise correlates of protection. Agonistic antibodies against the tumor necrosis factor receptor family member 4-1BB are emerging as a promising tool in cancer therapy, with evidence that these antibodies expand both T cells as well as innate immune cells. Depletion studies have suggested that several cell types can play a role in these immunotherapeutic regimens, but do not reveal which cells must directly receive the 4-1BB signals for effective therapy.We show that re-activated memory T cells are superior to resting memory T cells in control of an 8-day pre-established E.G7 tumor in mice. We find that ex vivo activation of the memory T cells allows the activated effectors to continue to divide and enter the tumor, regardless of antigen-specificity; however, only antigen-specific reactivated memory T cells show any efficacy in tumor control. When agonistic anti-4-1BB antibody is combined with this optimized adoptive T cell therapy, 80% of mice survive and are fully protected from tumor rechallenge. Using 4-1BB-deficient mice and mixed bone marrow chimeras, we find that it is sufficient to have 4-1BB only on the endogenous host alphabeta T cells or only on the transferred T cells for the effects of anti-4-1BB to be realized. Conversely, although multiple immune cell types express 4-1BB and both T cells and APC expand during anti-4-1BB therapy, 4-1BB on cells other than alphabeta T cells is neither necessary nor sufficient for the effect of anti-4-1BB in this adoptive immunotherapy model.This study establishes alphabeta T cells rather than innate immune cells as the critical target in anti-4-1BB therapy of a pre-established tumor. The study also demonstrates that ex vivo activation of memory T cells prior to infusion allows antigen-specific tumor control without the need for reactivation of the memory T cells in the tumor
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