18 research outputs found
Troglomorphic pseudoscorpions (Arachnida: Pseudoscorpiones) of northern Arizona, with the description of two new short-range endemic species
This study reports on the pseudoscorpion fauna of the subterranean ecosystems of northern Arizona, U.S.A. Our work resulted in the descriptions of two new species, Hesperochernes bradybaughi sp. nov. and Tuberochernes cohni sp. nov. (Chernetidae) and the range expansion of one species, Larca cavicola (Muchmore 1981) (Larcidae). All of these species were cave-adapted and found within caves on Grand Canyon-Parashant National Monument in northwestern Arizona. Based upon this work, the genus Archeolarca Hoff and Clawson is newly synonymized with Larca Chamberlin, and the following species are transferred from Archeolarca to Larca, forming the new combinations L. aalbui (Muchmore 1984), L. cavicola (Muchmore 1981), L. guadalupensis (Muchmore 1981) and L. welbourni (Muchmore 1981). Despite intensive sampling on the monument, the two new species were detected in only one cave. This cave supports the greatest diversity of troglomorphic arthropod species on the monument—all of which are short-range endemics occurring in only one cave. Maintaining the management recommendations provided by Peck and Wynne (2013) for this cave should aid in the long-term persistence of these new pseudoscorpion species, as well as the other troglomorphic arthropods
Localization, Dynamics, and Function of Survivin Revealed by Expression of Functional SurvivinDsRed Fusion Proteins in the Living Cell
Survivin, a member of the inhibitor of apoptosis protein family, has attracted growing attention due to its expression in various tumors and its potential application in tumor therapy. However, its subcellular localization and function have remained controversial: Recent studies revealed that survivin is localized at the mitotic spindle, binds caspases, and could thus protect cells from apoptosis. The cell cycle-dependent expression of survivin and its antiapoptotic function led to the hypothesis that survivin connects the cell cycle with apoptosis, thus providing a death switch for the termination of defective mitosis. In other studies, survivin was detected at kinetochores, cleavage furrow, and midbody, localizations being characteristic for chromosomal passenger proteins. These proteins are involved in cytokinesis as inferred from the observation that RNA interference and expression of mutant proteins led to cytokinesis defects without an increase in apoptosis. To remedy these discrepancies, we analyzed the localizations of a survivinDsRed fusion protein in HeLa cells by using confocal laser scanning microscopy and time-lapse video imaging. SurvivinDsRed was excluded from the interphase nucleus and was detected in centrosomes and at kinetochores. It dissociated from chromosomes at the anaphase/telophase transition and accumulated at the ends of polar microtubuli where it was immediately condensed to the midbody. Overexpression of both survivinDsRed and of a phosphorylation-defective mutant conferred resistance against apoptosis-inducing reagents, but only the overexpressed mutant protein caused an aberrant cytokinesis. These data characterize in detail the dynamics of survivin in vertebrate cells and confirm that survivin represents a chromosomal passenger protein
T-2 toxin-induced apoptosis involving Fas, p53, Bcl-xL, Bcl-2, Bax and caspase-3 signaling pathways in human chondrocytes*
Objective: To investigate the effects of T-2 toxin on expressions of Fas, p53, Bcl-xL, Bcl-2, Bax and caspase-3 on human chondrocytes. Methods: Human chondrocytes were treated with T-2 toxin (1~20 ng/ml) for 5 d. Fas, p53 and other apoptosis-related proteins such as Bax, Bcl-2, Bcl-xL, caspase-3 were determined by Western blot analysis and their mRNA expressions were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Results: Increases in Fas, p53 and the pro-apoptotic factor Bax protein and mRNA expressions and a decrease of the anti-apoptotic factor Bcl-xL were observed in a dose-dependent manner after exposures to 1~20 ng/ml T-2 toxin, while the expression of the anti-apoptotic factor Bcl-2 was unchanged. Meanwhile, T-2 toxin could also up-regulate the expressions of both pro-caspase-3 and caspase-3 in a dose-dependent manner. Conclusion: These data suggest a possible underlying molecular mechanism for T-2 toxin to induce the apoptosis signaling pathway in human chondrocytes by regulation of apoptosis-related proteins