Senescent cells play important roles in both physiological and pathological processes, including cancer and aging. In all cases, however, senescent cells comprise only a small fraction of tissues. Senescent phenotypes have been studied largely in relatively homogeneous populations of cultured cells. In vivo, senescent cells are generally identified by a small number of markers, but whether and ...

Senescent cell accumulation in aging tissues is linked to age-associated diseases and declining function, prompting efforts to eliminate them. Mass spectrometry analysis revealed that DPP4 (dipeptidyl peptidase 4) was selectively expressed on the surface of senescent, but not proliferating, human diploid fibroblasts. Importantly, the differential presence of DPP4 allowed flow cytometry-mediated...

The Mediterranean seagrass Posidonia oceanica (L.) Delile has been used for trace element (TE) biomonitoring since decades ago. However, present informations for this bioindicator are limited mainly to plant TE levels, while virtually nothing is known about their fluxes through P. oceanica meadows. We therefore contaminated seagrass bed portions in situ at two experimental TE levels with a mix ...

In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short-lived nitrogen (N) catabolite serving urease-mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels...

H. Oskar Schmidt Zentralinstitut für Genetik und Kulturpflanzenforschung der AdW der DDR, 4325 Gatersleben Z. Naturforsch. 43c, 149-154 (1988); received March 11/September 7, 1987 Senescence, Chloroplast, Gerontoplast, Thylakoid Membrane Proteins, Electronmicroscopy, Photosynthesis In the course of yellowing (senescence) the leaves of Vicia faba L. lose 95% of their chlorophyll. Gerontoplasts d...

Extending the carotenoid pathway to astaxanthin in plants is of scientific and industrial interest. However, expression of a microbial β-carotene ketolase (BKT) that catalyses the formation of ketocarotenoids in transgenic plants typically results in low levels of astaxanthin. The low efficiency of BKTs in ketolating zeaxanthin to astaxanthin is proposed to be the major limitation for astaxanth...

Fourteen strains of aquatic hyphomycete species that are common on decaying leaves in running waters were grown in liquid culture and analyzed for total ergosterol contents. Media included an aqueous extract from senescent alder leaves, a malt extract broth, and a glucose-mineral salt solution. Concentrations of ergosterol in fungal mycelium ranged from 2.3 to 11.5 mg/g of dry mass. The overall...

Seagrasses abound in the dynamic environment of shallow marine waters. From the often high annual biomass production it can be deduced that seagrass meadows have high requirements for inorganic nutrients, although the nutrient demands will be met to some extent by internal recycling. A series of processes lead to nutrient losses from the seagrass bed. Export of leaves and leaf fragments with cu...

Insect galls may be study models to test the distribution of pectins and arabinogalactan-proteins (AGPs) and their related functions during plant cell cycles. These molecules are herein histochemically and immunocitochemically investigated in the kidney-shaped gall induced by Baccharopelma dracunculifoliae (Psyllidae) on leaves of Baccharis dracunculifolia DC. (Asteraceae) on developmental basi...