Ray Newsam

University of Kent, Canterbury, ENG, United Kingdom

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Publications (9)18.37 Total impact

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    ABSTRACT: Mammalian cells cultured in vitro are able to recover from cold stress. However, the mechanisms activated during cold stress and recovery are still being determined. We here report the effects of hypothermia on cellular architecture, cell cycle progression, mRNA stability, protein synthesis and degradation in three mammalian cell lines. The cellular structures examined were, in general, well maintained during mild hypothermia (27-32 degrees C) but became increasingly disrupted at low temperatures (4-10 degrees C). The degradation rates of all mRNAs and proteins examined were much reduced at 27 degrees C, and overall protein synthesis rates were gradually reduced with temperature down to 20 degrees C. Proteins involved in a range of cellular activities were either upregulated or downregulated at 32 and 27 degrees C during cold stress and recovery. Many of these proteins were molecular chaperones, but they did not include the inducible heat shock protein Hsp72. Further detailed investigation of specific proteins revealed that the responses to cold stress and recovery are at least partially controlled by modulation of p53, Grp75 and eIF3i levels. Furthermore, under conditions of severe cold stress (4 degrees C), lipid-containing structures were observed that appeared to be in the process of being secreted from the cell that were not observed at less severe cold stress temperatures. Our findings shed light on the mechanisms involved and activated in mammalian cells upon cold stress and recovery.
    FEBS Journal 12/2008; 276(1):286-302. · 4.25 Impact Factor
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    ABSTRACT: Synergistic interactions between bacteria and arbuscular mycorrhizal fungi (AMF) occur under natural soil conditions; however, in polluted soils there is little information regarding these relationships. Microscopy was used to study the interaction between the hyphae of an AM fungus (Glomus claroideum BEG134 from an As/Cu polluted soil) and bacteria in polluted soil cultures. BacLightTM staining showed viable bacteria mainly in the runner hyphae of the fungus associated with plants (Holcus lanatus L.) growing in polluted soils. Transmission electron microscopy revealed that a morphologically different bacterial population was intimately associated with the extraradical mycelium (ERM). Bacteria were embedded in the mucilaginous outer layer, encrusted at the outer layer, between hyphal wall layers, and inside hyphae. Crystals, comprising precipitated metal, were observed outside the ERM. The ecological relevance of this bacteria–AMF interaction is discussed.
    Agrociencia 02/2008; 42(1):1-10. · 0.31 Impact Factor
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    ABSTRACT: The ultrastructural detail of spore development in Scutellospora heterogama is described. Although the main ontogenetic events are similar to those described from light microscopy, the complexity of wall layering is greater when examined at an ultrastructural level. The basic concept of a rigid spore wall enclosing two inner, flexible walls still holds true, but there are additional zones within these three walls distinguishable using electron microscopy, including an inner layer that is involved in the formation of the germination shield. The spore wall has three layers rather than the two reported previously. An outer, thin ornamented layer and an inner, thicker layer are both derived from the hyphal wall and present at all stages of development. These layers differentiate into the outer spore layer visible at the light microscope level. A third inner layer unique to the spore develops during spore swelling and rapidly expands before contracting back to form the second wall layer visible by light microscopy. The two inner flexible walls also are more complex than light microscopy suggests. The close association with the inner flexible walls with germination shield formation consolidates the preferred use of the term 'germinal walls' for these structures. A thin electron-dense layer separates the two germinal walls and is the region in which the germination shield forms. The inner germinal wall develops at least two sub-layers, one of which has an appearance similar to that of the expanding layer of the outer spore wall. An electron-dense layer is formed on the inner surface of the inner germinal wall as the germination shield develops, and this forms the wall surrounding the germination shield as well as the germination tube. At maturity, the outer germinal wall develops a thin, striate layer within its substructure.
    Mycorrhiza 08/2007; 17(5):395-403. · 2.96 Impact Factor
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    ABSTRACT: Accumulation and elimination of polycyclic aromatic hydrocarbons (PAHs) were studied in the fungus Fusarium solani. When the fungus was grown on a synthetic medium containing benzo[a]pyrene, hyphae of F. solani contained numerous lipid vesicles which could be stained by the lipid-specific dyes: Sudan III and Rhodamine B. The fluorescence produced by Rhodamine B and PAH benzo[a]pyrene were at the same locations in the fungal hyphae, indicating that F. solani stored PAH in pre-existing lipid vesicles. A passive temperature-independent process is involved in the benzo[a]pyrene uptake and storage. Sodium azide, a cytochrome c oxidation inhibitor, and the two cytoskeleton inhibitors colchicine and cytochalasin did not prevent the transport and accumulation of PAH in lipid vesicles of F. solani hyphae. F. solani degraded a large range of PAHs at different rates. PAH intracellular storage in lipid vesicles was not necessarily accompanied by degradation and was common to numerous other fungi.
    Environmental Pollution 02/2005; 133(2):283-91. · 3.73 Impact Factor
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    ABSTRACT: The Chinese hamster ovary (CHO) cell line has great commercial importance in the production of recombinant human proteins, especially those for therapeutic use. Much attention has been paid to CHO cell population physiology in order to define factors affecting product fidelity and yield. Such studies have revealed that recombinant proteins, including human interferon-gamma (IFN-gamma), can be heterogeneous both in glycosylation and in proteolytic processing. The type of heterogeneity observed depends on the growth physiology of the cell population, although the relationship between them is complex. In this article we report results of a cytological study of the CHO320 line which expresses recombinant human IFN-gamma. When grown in suspension culture, this cell line exhibited three types of heterogeneity: (1) heterogeneity of the production of IFN-gamma within the cell population, (2) heterogeneity of the number of nuclei and mitotic spindles in dividing cells, and (3) heterogeneity of cellular environment. The last of these arises from cell aggregates which form in suspension culture: Some cells are exposed to the culture medium; others are fully enclosed within the mass with little or no direct access to the medium. Thus, live cells producing IFN-gamma are heterogeneous in their environment, with variable access to O(2) and nutrients. Within the aggregates, it appears that live cells proliferate on a dead cell mass. The layer of live cells can be several cells deep. Specific cell-cell attachments are observed between the living cells in these aggregates. Two proteins, known to be required for the formation of certain types of intercellular junctions, spectrin and vinculin, have been localized to the regions of cell-cell contact. The aggregation of the cells appears to be an active process requiring protein synthesis. (c) 1995 John Wiley & Sons, Inc.
    Biotechnology and Bioengineering 04/1995; 46(2):147-58. · 4.16 Impact Factor
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    ABSTRACT: Quantitative and reproducible information concerning the development of the extraradical mycelium of arbuscular mycorrhizal fungi (AMF) is lacking due to the difficulties in extracting, identifying and estimating hyphal lengths. In this study, using a rhizobox growth system, the lengths of hyphae of AMF estimated using an image analysis system were not significantly different from data obtained by a trained observer using a modified grid-line intersect method. The assessment of lengths of hyphae on membrane filters or slides was, however, much quicker using image analysis, and allowed the complete sample to be quantified, unlike the grid-line method where a limited number of fields of view are assessed. The image analysis procedure is objective, observer-independent and less laborious than the manual method of assessment. Of the four different methods of sample preparation compared, membrane filter methods were found to be the most appropriate for quantitative sampling from three non-soil substrates. Glomus monosporum (UKC M3) produced twice as much extraradical mycelium and hyphal length per centimetre of colonised root than G. geosporum (BEG 11) on both leek and linseed in a durite sand at final harvest (63 days). Both AMF also produced more hyphal length per centimetre of colonised root on linseed than on leek. The spatial distribution of both AMF, however, was similar in durite sand and no correlation with levels of NaHCO3-extractable phosphorus was noted. In a third experiment, with G. manihotis (UKC INDO-1) colonising a tropical forage legume, Pueraria phaseoloides, in two other growth substrates, a different pattern of development of the extra-radical mycelium was observed. Because of a higher content of particulate matter, which collected on the membrane filters, the extraction technique had to be modified to give optimal performance of the image analysis system.
    Mycorrhiza 01/1994; 5(2):105-113. · 2.96 Impact Factor
  • Ray Newsam
    Mycologist 01/1991; 5(1):3-4.
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    ABSTRACT: Synergistic interactions between bacteria and arbuscular mycorrhizal fungi (AMF) occur under natural soil conditions; however, in polluted soils there is little information regarding these relationships. Microscopy was used to study the interaction between the hyphae of an AM fungus (Glomus claroideum BEG134 from an As/Cu polluted soil) and bacteria in polluted soil cultures. BacLight staining showed viable bacteria mainly in the runner hyphae of the fungus associated with plants (Holcus lanatus L.) growing in polluted soils. Transmission electron microscopy revealed that a morphologically different bacterial population was intimately associated with the extraradical mycelium (ERM). Bacteria were embedded in the mucilaginous outer layer, encrusted at the outer layer, between hyphal wall layers, and inside hyphae. Crystals, comprising precipitated metal, were observed outside the ERM. The ecological relevance of this bacteria-AMF interaction is discussed.
    Agrociencia, ISSN 1405-3195, Vol. 42, Nº. 1, 2008, pags. 1-10.
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    [Show abstract] [Hide abstract]
    ABSTRACT: Synergistic interactions between bacteria and arbuscular mycorrhizal fungi (AMF) occur under natural soil conditions; however, in polluted soils there is little information regarding these relationships. Microscopy was used to study the interaction between the hyphae of an AM fungus (Glomus claroideum BEG134 from an As/Cu polluted soil) and bacteria in polluted soil cultures. BacLight™ staining showed viable bacteria mainly in the runner hyphae of the fungus associated with plants (Holcus lanatus L.) growing in polluted soils. Transmission electron microscopy revealed that a morphologically different bacterial population was intimately associated with the extraradical mycelium (ERM). Bacteria were embedded in the mucilaginous outer layer, encrusted at the outer layer, between hyphal wall layers, and inside hyphae. Crystals, comprising precipitated metal, were observed outside the ERM. The ecological relevance of this bacteria-AMF interaction is discussed.