Reconstruction of sedimentary environments in Holocene coastal deposits of the southwest Netherlands; the Poortvliet boring,a case study of palaeoenvironmental diatom research

Diatoms are valuable indicators of palaeosedimentary environments in coastal wetlands. In this paper, the utilization of diatoms in coastal reconstructions will be demonstrated in a case study, the Poortvliet boring (southwest Netherlands). Diatoms supply valuable information about palaeosalinity gradients and palaeotide levels in addition to the existing geological data set, obtained from sediment cores.The ecological data of taxa are usually gathered from diatom studies in recent coastal environments. The study of the Poortvliet boring shows that information can also be obtained from the past (the past as key to the past) by comparing the trends of the relative abundances of species of which the ecology is well-known to those of which the ecology is unknown. It is argued both on recent and fossil data that Cymatosira belgica and Rhaphoneis minutissima have a tychoplanktonic life form.     

The binding of zinc in root cells of crop plants by phytic acid

Appreciable quantities of Zn are bound as Zn phytate (myo-inositol kis-hexaphosphate) within small vacuoles of cortical cells in the elongation zone of root tips of zinc tolerant Deschampsia caespitosa. These Zn/P-containing globular deposits have now been shown to occur in the roots of soybean, lucerne, lupins, tomato, rapeseed, cabbage, radish, wheat and maize. The globules are most frequent in the endodermis and pericycle but may also occur in the stele and inner cortex. The X-ray data again confirmed the presence of phytate with a relatively stable proportion of Zn and a species-dependent, variable, proportion of K, Mg and Ca to P.Analysis of soybean plants by atomic absorption spectroscopy showed that the Zn concentration in the shoots doubled in response to an increase in Zn supply from 1 to 100 M while the concentration of Zn in the root symplast was approximately 22 times greater than in the shoot, suggesting restricted transport to the shoot. It is suggested that the genetic expression of the capacity to bind heavy metals by means of phytate in endodermal cells may provide a strategy for keeping the above-ground content of heavy metals low. It may be possible to incorporate the trait into transformed roots that can be utilized for the treatment of industrial wastes.     

Palaeofloristic assemblages and palaeoecology of the Lower Oligocene Bembridge Marls, Hamstead Ledge, Isle of Wight

A sequence of nine, plant-macrofossil-bearing horizons has been recognized in the Lower Oligocene from the Isle of Wight, England. The plant fossils are contained in finely laminated, olive-brown to black silty-clays and clays. Some horizons exhibit rhythmic alternation of sediment couplets; others show evidence of bioturbation and rootlet penetration. These horizons are included within a sequence of finely laminated greenish grey silty-clays and clays, largely devoid of plant macrofossil material. The plant-bearing horizons contain abundant fruits, seeds, fern sporangia, Azolla megaspores, and rare leaves. The nearest living relatives of the fossils all inhabit an aquatic or marginal aquatic environment. The associated fossil fauna includes lake bottom and lake margin species. The palynoflora of the plant-bearing and immediately underlying horizons includes large numbers of planktonic algae and limited representatives of a forest vegetation. It shows a strong relationship between the occurrences of Sparganiaceaepollenites pollen and of Typha macrofossils. Palaeoecological interpretations of this plant-fossil-bearing sequence are discussed with particular reference to modern environments.
One new genus and three new species are described. Emendations are presented for four other species. Stratiotes leaf margin teeth are described.     

Localization of Possible Calcium-Binding Sites in the Cilia of Paramecium caudatum

SYNOPSIS. Electron-dense deposits indicating possible Ca-binding sites were found at the ciliary base of Paramecium caudatum fixed in a glutaraldehyde solution containing 5 mM CaCl₂. The deposits appeared mainly at the inner surface of the ciliary membrane above the "ciliary necklace" region, although they could also occur in the space between the outer and the central microtubules. In some cases a ring of exactly 9 deposits was found in a ciliary cross section of a cilium.     

Prion protein with Y145STOP mutation induces mitochondria-mediated apoptosis and PrP-containing deposits in vitro

A pathogenic truncation of an amber mutation at codon 145 (Y145STOP) in Gerstmann-Straussler-Scheinker disease (GSS) was investigated through the real-time imaging in living cells, by utilizing GFP-PrP constructs. GFP-PrP(1-144) exhibited an aberrant localization to mitochondria in mouse neuroblastoma neuro2a (N2a) and HpL3-4 cells, a hippocampal cell line established from prnp gene-ablated mice, whereas full-length GFP-PrP did not. The aberrant mitochondrial localization was also confirmed by Western blot analysis. Since GFP-PrP(1-121), as previously reported, and full-length GFP-PrP do not exhibit such mitochondrial localization, the mitochondrial localization of GFP-PrP(1-144) requires not only PrP residues 121-144 (in human sequence) but also COOH-terminal truncation in the current experimental condition. Subsequently, the GFP-PrP(1-144) induced a change in the mitochondrial innermembrane potential (DeltaPsi(m)), release of cytochrome c from the intermembrane space into the cytosol, and DNA fragmentation in these cells. Non-fluorescent PrP(1-144) also induced the DNA fragmentation in N2a and HpL3-4 cells after the proteasomal inhibition. These data may provide clues as to the molecular mechanism of the neurotoxic property of Y145STOP mutation. Furthermore, immunoelectron microscopy revealed numerous electron-dense deposits in mitochondria clusters of GFP-PrP(1-144)-transfected N2a cells, whereas no deposit was detected in the cells transfected with full-length GFP-PrP. Co-localization of GFP/PrP-immunogold particles with porin-immunogold particles as a mitochondrial marker was observed in such electron-dense vesicular foci, resembling those found in autophagic vacuoles forming secondary lysosomes. Whether such electron-dense deposits may serve as a seed for the growth of amyloid plaques, a characteristic feature of GSS with Y145STOP, awaits further investigations.     

The effect of single and concomitant pathogen infections on condition and fecundity of the wild rabbit (Oryctolagus cuniculus)

We assessed the effect of two pathogens (myxoma virus and Eimeria stiedae) and five macroparasites (gastrointestinal helminth species) of the wild rabbit (Oryctolagus cuniculus) upon total host body mass and abdominal fat level. Additionally, we assessed the effects of these organisms on the number of foetuses in adult females during the peak breeding period. Both mass of abdominal fat and total body mass of the rabbit were negatively associated with myxoma virus infection and increasing helminth species richness. Total body mass was also negatively associated with the protozoan parasite E. steidae. No relationship was found between any of the parasites/pathogens and the number of foetuses in adult females, although only relatively small sample sizes were available for this section of the analysis. Increasing host body mass was positively associated with number of foetuses and we propose that mass reduction caused by the pathogen and parasite species could also have the consequence of reducing foetal number.     

Amyloid Peptide Channels

At least 16 distinct clinical syndromes including Alzheimer’s disease (AD), Parkinson’s disease (PD), rheumatoid arthritis, type II diabetes mellitus (DM), and spongiform encephelopathies (prion diseases), are characterized by the deposition of amorphous, Congo red-staining deposits known as amyloid. These “misfolded” proteins adopt β-sheet structures and aggregate spontaneously into similar extended fibrils despite their widely divergent primary sequences. Many, if not all, of these peptides are capable of forming ion-permeable channels in vitro and possibly in vivo. Common channel properties include irreversible, spontaneous insertion into membranes, relatively large, heterogeneous single-channel conductances, inhibition of channel formation by Congo red, and blockade of inserted channels by Zn²⁺. Physiologic effects of amyloid, including Ca²⁺ dysregulation, membrane depolarization, mitochondrial dysfunction, inhibition of long-term potentiation (LTP), and cytotoxicity, suggest that channel formation in plasma and intracellular membranes may play a key role in the pathophysiology of the amyloidoses.     

Presence of esterase inPinaceae pollen

General esterases, like wall heterologous enzymes, may be implicated in allergenic mechanisms. We cytochemically examined the presence of these enzymes, bearing in mind thatPinus spp. is often considered a possible cause of allergies. Positive esterase results in fungus spores were found on the strip of a volumetric sampler. Data are reported here, together with the hypothesis of a possible esterase-allergenic link regarding fungus spores.     

Redistribution of phosphate deposits in the algaScenedesmus quadricauda deprived of exogenous phosphate—an ultra-cytochemical study

Summary The green algaScenedesmus quadricauda (Turp.) Bréb. was cultivated in the presence or absence of orthophosphate and synchronized daughter or mother cells were cytochemically stained. Forin situ capturing of water soluble phosphates Ca²⁺ and Mg²⁺ ions were added to the ice-cold glutaraldehyde fixative to form a polymeric metal-phosphate complex which was equivalent to the energy-rich condensed polyphosphates in staining by alkaline lead acetate. The X-ray microanalysis of the extensive stained deposits proved the presence of phosphorus. In orthophosphate-supplied daughter cells cytoplasmic vacuoles contained round stained bodies; a layer of phosphate-containing paracrystals encompassing some starch grains and a fine stained layer delineating the chloroplast envelope were also observed. In the equivalent mother cells only the material inside theloculi of stacked thylakoids was stained. In orthophosphate starved daughter cells filamentous phosphate-containing paracrystals filled extensive cytoplasmic vacuoles. A stained layer covered the chloroplast envelope and continuous stained layers appeared inside theloculi of stacked thylakoids. Mother cells that develop from these daughter cells were filled with starch grains and showed only peripheral stained deposits. The results are compared with the biochemical evidence of phosphate turnover in algal cells.Abbreviations ADP adenosine diphosphate - ATP adenosine triphosphate - ATPase adenosine triphosphatase - EDAX energy dispersive analysis of X-rays - Pi orthophosphate - PPi pyrophosphate - PP polyphosphate - PhAR photosynthetic active radiation - TCA trichloroacetic acid     

Synthesis and evaluation of styrylpyran fluorophores for noninvasive detection of cerebral β-amyloid deposits

The development of amyloid-specific fluorophores allows the visualization of cerebral β-amyloid deposits using optical imaging technology. In the present study, a series of smart styrylpyran fluorophores with compact donor–acceptor architecture were designed and evaluated for noninvasive detection of cerebral β-amyloid deposits. Spectral behavior of the fluorophores changed significantly (optical turn-on) upon binding to β-amyloid aggregates. Computational studies were conducted to correlate the experimental K_d values with calculated binding energies, speculating the relationship between fluorophore structure and β-amyloid affinity. In vivo studies demonstrated that PAD-2 could discriminate APP/PS1 transgenic mice from wild type controls, with specific labeling of cerebral β-amyloid deposits confirmed by ex vivo observation. Collectively, these styrylpyran fluorophores could provide a new scaffold for the development of optical imaging probes targeting cerebral β-amyloid deposits.