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Provides information on a study of Ifremeria nautilei from the North Fiji Basin concentrating on an (ultra)structural survey of the bacterial symbiosis to scrutinize important details previously not sufficiency documented. Methodology used to conduct the study; Results of the study; Discussion on the results.

Examines the ultrastructure and anaerobic respiration of the mitochondria in the oligochaete, Tubificoides benedii after hypoxia and exposure to sulfide levels. Utilization of succinate as keyproduct of anaerobic metabolism; Increase of succinate levels under hypoxic and hypoxic-sulfidic conditions; Occurrence of mitochondrial anaerobiosis.

Intermediate filament polypeptides (IFPs) are prominent components of cytoplasmic aggregates, which are pathognomonic for multiple diseases. Recent observations in cultured cells suggest that they are dynamic and subject to regulated turnover. The emerging concept is that multiple factors contribute to motility and turnover of IFP-containing aggregates. To understand their relative contribution, quantitative tools are needed. The current study addresses this need using epithelial cells producing mutant keratin IFPs that have been identified as the cause of the hereditary blister-forming skin disease epidermolysis bullosa simplex. Digital image analysis of individual granules allowed mapping of their complete life cycle, with information on multiple characteristics at any given time-point. The deduced signet features revealed rapid granule fusion and directed transport from the periphery towards the cell centre, and a limited, ~ 30 min lifetime with a slow, continuous growth phase followed by fast disassembly. As paradigmatic proof-of-principle, we demonstrate that inhibition of myosin II selectively reduces granule movement, linking keratin granule motility to retrograde cortical acto-myosin flow. The newly developed methods and established parameters will help in the characterization of known and the identification of novel regulators of IFP-containing aggregates. [ABSTRACT FROM AUTHOR]

Keratins are wide used markers for malignant epithelial cells, but their primary function is stabilization of epithelial tissues. Nevertheless, during metastasis, epithelia cells change from sessile cells into migrating cells. Consequently the stable keratin filament network connected to desmosomes has to undergo significant alterations which are required in a moving cell. Here we describe the involvement of keratins in the migration processes, which is typical for malignant cells. We want to answer the question how an altered keratin network of a migrating cell is built up, where this process takes place and how it is regulated. Using time lapse video microscopy of cells expressing fluorescently labelled keratins, we could show the formation of the new keratin network in the emerging lamellipodia of migrating cells. Close to the leading edge of lamellipodia, in direct proximity to focal contacts, the birth of keratin filament precursors (KFPs) could be observed as newly appearing fluorescent granules that subsequently elongate. During this elongation period, the KFPs moved retrograde along actin fibers and merged with the existing keratin network which was located further backwards in the lamellipodium. To further examine the origin of keratin protein forming KFPs, we fused photoactivable GFP (paGFP) to keratin. By examination of living cells expressing this protein, we could follow the dissociation of soluble keratin-paGFP from existing perinuclear filaments and the subsequent incorporation of keratin-paGFP in newly forming GFPs. We propose that these processes are part of a continuous turnover cycle of the keratin network, which enables the fast organization of the keratin network in the lamellipodia of migrating epithelial cells. [ABSTRACT FROM AUTHOR]