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81.
Abstract. The trophosome of adults of Riftia pachyptila (Vestimentifera) was reinvestigated using 3-dimensional ultrastructural reconstruction and quantitative morphological analysis. The symbionts make up 24.1%, the symbiont-containing cells (bacteriocytes) are 70.5% of the trophosome's volume. The trophosome is composed of lobules that have a central axial blood vessel surrounded by a myoepithelium containing bacteriocytes, in turn surrounded by an apolar tissue of bacteriocytes. Part of the splanchnic peritoneum lining the trunk coelom encases the bacteriocytes and forms a ramifying network of peripheral blood vessels. Based on the morphology and ultrastructure of the adult, we hypothesize a mesodermal rather than endodermal origin of trophosome and its constitute bacteriocytes. Some of the central bacteriocytes are part of the myoepithelium surrounding the axial blood vessel and act as stem cells for a proliferating tissue produced in the center and ultimately degraded at the periphery of each lobule. Similarly, the rod-shaped symbionts in the center act as stem cells and exhibit a simple cell cycle. Differentiation into cocci takes place in the median and peripheral zone. Lysis of cocci occurs in the degenerative zone. 相似文献
82.
Deep-sea vestimentiferan tubeworms, which live in symbiosis with bacteria, exhibit different life strategies according to
their habitat. At unstable and relatively short-lived hydrothermal vents, they grow extremely fast, whereas their close relatives
at stable and long-persisting cold seeps grow slowly and live up to 300 years. Growth and age differences are thought to occur
because of ecological and physiological adaptations. However, the underlying mechanisms of cell proliferation and death, which
are closely linked to homeostasis, growth, and longevity, are unknown. Here, we show by immunohistochemical and ultrastructural
cell cycle analyses that cell proliferation activities of the two species studied are higher than in any other characterized
invertebrate, being only comparable with tumor and wound-healing processes. The slow growth in Lamellibrachia luymesi from cold seeps results from balanced activities of proliferation and apoptosis in the epidermis. In contrast, Riftia pachyptila from hydrothermal vents grows fast because apoptosis is down-regulated in this tissue. The symbiont-housing organ, the trophosome,
exhibits a complex cell cycle and terminal differentiation pattern in both species, and growth is regulated by proliferation.
These mechanisms have similarities to the up- and down-regulation of proliferation or apoptosis in various types of tumor,
although they occur in healthy animals in this study, thus providing significant insights into the underlying mechanisms of
growth and longevity.
Financial support was provided by the Austrian Science Foundation (FWF; grants to M.B.), a DOC scholarship from the Austrian
Academy of Science (to B.P.), and grants from the US National Science Foundation (to C.R. Fisher). 相似文献
83.
Jennifer D. Lewis Laura A. Sullivan Jennifer A. Byrne Werner de Riese Robert K. Bright 《Cancer immunology, immunotherapy : CII》2009,58(8):1337-1349
Tumor protein D52 (TPD52) is involved in cellular transformation, proliferation and metastasis. TPD52 over expression has been demonstrated in several cancers including prostate, breast, and ovarian carcinomas. Murine TPD52 (mD52) has been shown to induce anchorage independent growth in vitro and metastasis in vivo, and mirrors the function and normal tissue expression patterns of the human orthologue of TPD52. We believe TPD52 represents a self, non-mutated tumor associated antigen (TAA) important for maintaining a transformed and metastatic cellular phenotype. The transgenic adeno-carcinoma of the mouse prostate (TRAMP) model was employed to study mD52 as a vaccine antigen. Naïve mice were immunized with either recombinant mD52 protein or plasmid DNA encoding the full-length cDNA of mD52. Following immunization, mice were challenged with a subcutaneous, tumorigenic dose of mD52 positive, autochthonous TRAMP-C1 tumor cells. Sixty percent of mice were tumor free 85 days post challenge with TRAMP-C1 when immunized with mD52 as a DNA-based vaccine admixed with soluble granulocyte-macrophage colony stimulating factor (GM-CSF). Survivors of the initial tumor challenge rejected a second tumor challenge given in the opposite flank approximately 150 days after the first challenge, and remained tumor free for more than an additional 100 days. The T cell cytokine secretion patterns from tumor challenge survivors indicated that a TH1-type cellular immune response was involved in tumor protection. These data suggest that mD52 vaccination induced a memory, cellular immune response that resulted in protection from murine prostate tumors that naturally over express mD52 protein. 相似文献
84.
To demonstrate pathological changes due to white spot virus infection in Fenneropenaeus indicus, a batch of hatchery bred quarantined animals was experimentally infected with the virus. Organs such as gills, foregut, mid-gut, hindgut, nerve, eye, heart, ovary and integument were examined by light and electron microscopy. Histopathological analyses revealed changes hitherto not reported in F. indicus such as lesions to the internal folding of gut resulted in syncytial mass sloughed off into lumen, thickening of hepatopancreatic connective tissue with vacuolization of tubules and necrosis of rectal pads in hindgut. Virus replication was seen in the crystalline tract region of the compound eye and eosinophilic granules infiltrated from its base. In the gill arch, dilation and disintegration of median blood vessel was observed. In the nervous tissues, encapsulation and subsequent atrophy of hypertrophied nuclei of the neurosecretory cells were found. Transmission electron microscopy showed viral replication and morphogenesis in cells of infected tissue. De novo formed vesicles covered the capsid forming a bilayered envelop opened at one end inside the virogenic stroma. Circular vesicles containing nuclear material was found fused with the envelop. Subsequent thickening of the envelop resulted in the fully formed virus. In this study, a correlation was observed between the stages of viral multiplication and the corresponding pathological changes in the cells during the WSV infection. Accordingly, gill and foregut tissues were found highly infected during the onset of clinical signs itself, and are proposed to be used as the tissues for routine disease diagnosis. 相似文献
85.
E Bright D 《ZooKeys》2010,(56):45-48
A new genus of Scolytidae (Coleoptera), Stevewoodia, from St. Lucia in the Lesser Antilles, is herein named and described. The type species, Stevewoodia minutumsp. n. is also named. The genus is named in honor of the late Steven L. Wood for his many contributions to the systematics of the Scolytidae. 相似文献
86.
V. J. Rejish Kumar Cini Achuthan N. J. Manju Rosamma Philip I. S. Bright Singh 《World journal of microbiology & biotechnology》2009,25(3):407-414
Two distinct nitrifying bacterial consortia, namely an ammonia oxidizing non-penaeid culture (AMONPCU-1) and an ammonia oxidizing
penaeid culture (AMOPCU-1), have been mass produced in a nitrifying bacterial consortia production unit (NBCPU). The consortia,
maintained at 4°C were activated and cultured in a 2 l fermentor initially. At this stage the net biomass (0.105 and 0.112 g/l),
maximum specific growth rate (0.112 and 0.105/h) and yield coefficients (1.315 and 2.08) were calculated respectively, for
AMONPCU-1 and AMOPCU-1 on attaining stationary growth phase. Subsequently on mass production in a 200 l NBCPU under optimized
culture conditions, the total amounts of NH4
+–N removed by AMONPCU-1 and AMOPCU-1 were 1.948 and 1.242 g/l within 160 and 270 days, respectively. Total alkalinity reduction
of 11.7–14.4 and 7.5–9.1 g/l were observed which led to the consumption of 78 and 62 g Na2CO3. The yield coefficient and biomass of AMONPCU-1 were 0.67 and 125.3 g/l and those of AMOPCU-1 were 1.23 and 165 g/l. The
higher yield coefficient and growth rate of AMOPCU-1 suggest better energy conversion efficiency and higher CO2 fixation potential. Both of the consortia were dominated by Nitrosomonas-like organisms. The consortia may find application in the establishment of nitrification within marine and brackish water
culture systems. 相似文献
87.
88.
Martinus AM van Boekel Erik R Vossenaar Frank HJ van den Hoogen Walther J van Venrooij 《Arthritis research & therapy》2001,3(2):1-7
This review focuses on the mechanisms of stress response in the synovial tissue of rheumatoid arthritis. The major stress factors, such as heat stress, shear stress, proinflammatory cytokines and oxidative stress, are discussed and reviewed, focusing on their potential to induce a stress response in the synovial tissue. Several pathways of stress signalling molecules are found to be activated in the synovial membrane of rheumatoid arthritis; of these the most important examples are heat shock proteins, mitogen-activated protein kinases, stress-activated protein kinases and molecules involved in the oxidative stress pathways. The expression of these pathways in vitro and in vivo as well as the consequences of stress signalling in the rheumatoid synovium are discussed. Stress signalling is part of a cellular response to potentially harmful stimuli and thus is essentially involved in the process of synovitis. Stress signalling pathways are therefore new and promising targets of future anti-rheumatic therapies. 相似文献
89.
Paul M Kulesa Jessica M Teddy Miranda Smith Richard Alexander Cameron HJ Cooper Rusty Lansford Rebecca McLennan 《BMC developmental biology》2010,10(1):101
Background
Tracing cell dynamics in the embryo becomes tremendously difficult when cell trajectories cross in space and time and tissue density obscure individual cell borders. Here, we used the chick neural crest (NC) as a model to test multicolor cell labeling and multispectral confocal imaging strategies to overcome these roadblocks. 相似文献90.
A community of organisms dominated by gnathostomulids has been discovered at the East Flower Garden Brine Seep. This discovery clearly demonstrates that specialized communities of micro-metazoans exist in and below sulfide-dependent chemoclines. The term thiobios should be retained to describe these communities. 相似文献