Joanne Marrison - Academia.edu (original) (raw)

Papers by Joanne Marrison

Dalton Transactions

New Ru complexes are described that have the potential to interact with DNA in the three ways sho... more New Ru complexes are described that have the potential to interact with DNA in the three ways shown and this may be the reason why some of these complexes have such high antiproliferative activity.

BackgroundAn emerging problem in the treatment of breast cancer is the increasing incidence of me... more BackgroundAn emerging problem in the treatment of breast cancer is the increasing incidence of metastases to the brain. Metastatic brain tumours are incurable and can cause epileptic seizures and cognitive impairment, so better understanding of this niche, and the cellular mechanisms, is urgently required. Microglia are the resident brain macrophage population, becoming “activated” by neuronal injury, eliciting an inflammatory response. Microglia promote proliferation, angiogenesis and invasion in brain tumours and metastases. However, the mechanisms underlying microglial involvement appear complex and better models are required to improve understanding of function.MethodsHere, we sought to address this need by developing a model to study metastatic breast cancer cell-microglial interactions using intravital imaging combined with ex vivo electrophysiology. We implanted an optical window on the parietal bone to facilitate observation of cellular behaviour in situ in the outer cortex ...

Chemical Science

Drug-like, donor–acceptor diphenylacetylenes cause efficient cell death upon photoactivation and ... more Drug-like, donor–acceptor diphenylacetylenes cause efficient cell death upon photoactivation and hence have potential phototherapeutic applications.

Tumor stem cells and malignant multicellular networks have been separately implicated in the ther... more Tumor stem cells and malignant multicellular networks have been separately implicated in the therapeutic resistance of Glioblastoma Multiforme (GBM), the most aggressive type of brain cancer in adults. We show that small molecule inhibition of RHO-associated serine/threonine kinase (ROCKi) significantly promoted the outgrowth of neurite-like cell projections in cultures of heterogeneous patient-derived GBM stem-like cells. These projections formed de novo-induced cellular network (iNet) webs, which regressed after withdrawal of ROCKi. Connected cells within the iNet web exhibited long range calcium signal transmission, and significant lysosomal and mitochondrial trafficking. In contrast to their less-connected vehicle control counterparts, iNet cells remained viable and proliferative after high-dose radiation. These findings demonstrate a link between ROCKi-regulated cell projection dynamics and the formation of radiation-resistant multicellular networks. Our study identifies means ...

Plant Physiology, 1993

We report the visualization of peroxisomes in tobacco (Nicotiana tabacum) leaves using fluorescen... more We report the visualization of peroxisomes in tobacco (Nicotiana tabacum) leaves using fluorescently labeled antibodies to glycolate oxidase. In transgenic tobacco leaves the expression of isocitrate lyase was also visualized. In dual probing experiments both enzymes were shown to be present together in all peroxisomes in transgenic tobacco leaves.

Journal of Experimental Botany, Nov 1, 1991

ABSTRACT The three-dimensional quantitative leaf anatomy in developing young (9-22 d) first leave... more ABSTRACT The three-dimensional quantitative leaf anatomy in developing young (9-22 d) first leaves of wild type Arabidopsis thaliana cv. Landsberg erecta from mitosis through cell and leaf expansion to the cessation of lamina growth has been studied. The domains of cell division, the relative proportion of the cell types present during development and the production of intercellular space in the developing leaf have been determined by image analysis of entire leaves sectioned in three planes. Mitotic activity occurs throughout the youngest leaves prior to unfolding and cell expansion is initiated firstly at the leaf tip with a persistent zone of mitotic cells at the leaf base resulting in a gradient of development along the leaf axis, which persists in the older leaves. Major anatomical changes which occur during the development are, a rapid increase in mesophyll volume, an increase in the vein network, and expansion of the intercellular spaces. The pattern of cell expansion results in a 10-fold variation in mesophyll cell size in mature leaves. In the youngest leaves the plan area of mesophyll cells varies between 100-mu-m2 and 400-mu-m2 whereas in mature leaves mesophyll cells range in plan area from 800-mu-m2 to 9500-mu-m2. The volumes of mesophyll tissue and airspace under unit leaf area increase 3-fold and 35-fold, respectively, during leaf expansion. The volume proportions of tissue types mesophyll:airspace:epidermal:vascular in the mature leaf are 61:26:12:1, respectively. This study provides comparative information for future identification and analysis of leaf development mutants of Arabidopsis thaliana.

Plant physiology, 1996

The coordination of the synthesis of chlorophyll (Chl) and light-harvesting Chl proteins was dete... more The coordination of the synthesis of chlorophyll (Chl) and light-harvesting Chl proteins was determined by observing the sequence of appearance of the specific mRNAs for the nuclear genes CHLH, Por, and Lhcb1*2 (AB180). CHLH encodes a magnesium protoporphyrin chelatase subunit that is involved in the first committed step in Chl biosynthesis; Por encodes protochlorophyllide oxidoreductase, which catalyzes the penultimate and only light-dependent step in Chl biosynthesis; and Lhcb1*2 encodes light-harvesting Chl a/b binding protein of the type-1 light-harvesting complex of photosystem II. Using digoxigenin-labeled antisense and sense RNA probes and a highly sensitive in situ hybridization technique, we have visualized the first appearance of the specific mRNAs in postmitotic mesophyll cells of developing 7-d-old wheat leaves (Triticum aestivum cv Maris dove). The transcripts for CHLH and POR are detectable in the youngest (18 h postmitotic) leaf tissue containing dividing cells; light...

Plant physiology, 1999

Acclimation of leaves to high light (HL; 650 micromol m(-2) s(-1)) was investigated in the long-l... more Acclimation of leaves to high light (HL; 650 micromol m(-2) s(-1)) was investigated in the long-lived epiphytic bromeliad Guzmania monostachia and compared with plants maintained under low light (LL; 50 micromol m(-2) s(-1)). Despite a 60% decrease in total chlorophyll in HL-grown plants, the chlorophyll a/b ratio remained stable. Additionally, chloroplasts from HL-grown plants had a much lower thylakoid content and reduced granal stacking. Immunofluorescent labeling techniques were used to quantify the level of photosynthetic polypeptides. HL-grown plants had 30% to 40% of the content observed in LL-grown plants for the light-harvesting complex associated with photosystems I and II, the 33-kD photosystem II polypeptide, and Rubisco. These results were verified using conventional biochemical techniques, which revealed a comparable 60% decrease in Rubisco and total soluble protein. When expressed on a chlorophyll basis, the amount of protein and Rubisco was constant for HL- and LL-gr...

The Plant journal : for cell and molecular biology, 2000

A new method is described for fluorescent imaging of mature Arabidopsis embryos that enables thei... more A new method is described for fluorescent imaging of mature Arabidopsis embryos that enables their cellular architecture to be visualized without the need for histological sectioning. Mature embryos are stained with aniline blue and cleared with chloral hydrate to allow high-resolution confocal imaging of individual cells within the embryo prior to germination. The technique allows the collection of longitudinal optical sections throughout the cotyledon, hypocotyl and root of wild-type Arabidopsis C24 embryos. Every cell within the mature embryo can be visualized with sufficient clarity and resolution to allow three-dimensional analysis of cellular architecture. Optical sectioning of mutant gnom, short-root and scarecrow embryos, and through root meristems disrupted as a consequence of targeted misexpression of diphtheria toxin, demonstrate the potential of this technique for visualizing the cellular organization of mutant and perturbed embryonic phenotypes.

The Plant Journal, 1992

This paper describes the first localization of immunofluorescence of topoisomerase II in developi... more This paper describes the first localization of immunofluorescence of topoisomerase II in developing chloroplasts. In order to investigate the relationship between topoisomerase II and chloroplast DNA (ctDNA) replication during chloroplast development the 7-day-old wheat leaf was used. Topoisomerase II was immunolabelled and fluorescein tagged and the ctDNA simultaneously stained with 4,6-diamidino-2phenylindole (DAPI) in the same sections. Topoisomerase II was detected at every stage of chloroplast development and maximal levels of topoisomerase II were found in chloroplasts at the time of ctDNA replication. Topoisomerase II was localized around the plastid periphery, exactly mirroring the position of the ctDNA. After chloroplast division both topoisomerase II and ctDNA are seen to be restricted to small discrete areas within the plastid, but at different sites. These findings strongly suggest a role fortopoisomerase II in ctDNA decatenation prior to chloroplast division.

The Plant Journal, 1994

ABSTRACT We have developed and optimized methods for the in situ hybridization to mRNA and rRNA t... more ABSTRACT We have developed and optimized methods for the in situ hybridization to mRNA and rRNA to enable the specific localization of transcripts within the leaf cell to cytoplasmic or to organelle compartments. Polyethylene glycol embedded leaf tissue was probed using digoxigenin labelled RNA probes and the hybridization products visualized using anti-digoxigenin alkaline phosphatase, nitroblue tetrazolium chloride and 5-bromo-4-chloro-3-indolyl phosphate. The specificity and discrimination of the technique is illustrated by the discrete localization of three transcripts: (a) the chloroplast encoded Rubisco large subunit mRNA; (b) the nuclear encoded 25S ribosomal RNA; and (c) a nuclear encoded transcript bearing strong homology to the cs gene putatively responsible for the chelation of magnesium by protoporphyrin. Each transcript is shown to have a precise intracellular distribution as follows: a is confined to the chloroplast, b is confined to the cytoplasmic compartment and c is within the cytoplasmic compartment, with enhanced localization round the chloroplast. We also describe the expansion of the method to visualize a specific mRNA and its related protein within the same cell or same organelle in the same section. This is achieved using sequential probing and employing two indicator fluorochromes with different emissions to facilitate simultaneous specific recognition of endogenous transcripts and proteins. The application of these techniques is discussed.

The Plant Journal, 1996

Using scanning light microscopy software to detect and measure immunofluorescence in leaf section... more Using scanning light microscopy software to detect and measure immunofluorescence in leaf sections Rubisco concentration in situ in chloroplasts has been accurately determined throughout development. The fluorescence measurements were calibrated by comparison with values for Rubisco accumulation obtained from rocket immuno-electrophoresis profiles of soluble protein from isolated cells and from chloroplasts using a purified sample of Rubisco as the standard. It has been shown that in situ immunofluorescence can be used for cytoquantitation of proteins within individual chloroplasts to a sensitivity of 1fg and also for the comparison of the protein levels in adjacent chloroplasts and cells. Several important applications of this new technique are discussed.

PLANT PHYSIOLOGY, 1996

We have isolated and sequenced a cDNA from Arabidopsis thaliana cv C24 that encodes a putative Mg... more We have isolated and sequenced a cDNA from Arabidopsis thaliana cv C24 that encodes a putative Mg chelatase subunit. The deduced amino acid sequence shows a very high level of identity to a gene previously characterized from Antirrhinum majus (olive) and also high similarity to bchH, a bacterial gene involved in the Mg chelatase reaction of bacteriochlorophyll biosynthesis. We suggest that this gene be called CHL H. Northern blot analyses were used to investigate the expression of CHL H, another putative Mg chelatase gene, ch-42, and ferrochelatase. The CHL H transcript was observed to undergo a dramatic diurnal variation, rising almost to its maximum level by the end of the dark period, then increasing slightly at the onset of the light and declining steadily to a minimum by the end of the light period; in contrast, transcripts for ch-42 and ferrochelatase remained constant. A model is proposed in which the CHL H protein plays a role in regulating the levels of chlorophyll during t...

FEBS Letters, 1989

Western blotting of total cell extracts from the young developing wheat leaf with an antibody to ... more Western blotting of total cell extracts from the young developing wheat leaf with an antibody to yeast topoisomerase II locates two proteins of molecular mass 96-101 kDa which also appear on blots of chloroplast proteins. The maximal levels of both proteins are present in chloroplasts in which chloroplast DNA replication is occurring prior to chloroplast division. Topoisomerase; Chloroplast DNA; Chloroplast development; Western blotting; (Mesophyll cell)

Plant …, 1996

Castor Bean lsocitrate Lyase Lacking the Putative ... Peroxisomal Targeting Signal -1 ARM 1s lmpo... more Castor Bean lsocitrate Lyase Lacking the Putative ... Peroxisomal Targeting Signal -1 ARM 1s lmported into Plant ... Peroxisomes Both in Vitro and in Vivo' ... Xiaoping Gao, Joanne 1. Marrison, Martin R. Pool, Rache1 M. Leech, and Alison Baker* Department of ...

Imaging & Microscopy, 2006

This 7 th International European Light Microscopy Initiative (ELMI) course on Advanced Light Micr... more This 7 th International European Light Microscopy Initiative (ELMI) course on Advanced Light Microscopy will be held in the historic city of York in the UK. York is set in the centre of the Vale of York surrounded by the Yorkshire Dales, Moors and Wolds. This walled city is one of the premier tourist attractions in the UK, with its medieval guild halls and hostelries offering many visitor attractions, including the Jorvik Viking Centre, the National Railway Museum, York Minster, York Castle Museum, Clifford's Tower and the Merchant Adventurers' Hall.

Cellular Microbiology, 2012

, together with the peripheral membrane protein SHERP (small hydrophilic endoplasmic reticulum-as... more , together with the peripheral membrane protein SHERP (small hydrophilic endoplasmic reticulum-associated protein), are essential for parasite differentiation (metacyclogenesis) in the sand fly vector. HASPB is a 'nonclassically' secreted protein, requiring N-terminal acylation for trafficking to and exposure on the plasma membrane. Here, we use live cell imaging methods to further explore this pathway to the membrane and flagellum. Unlike HASPB trafficking in transfected mammalian cells, we find no evidence for a phosphorylation-regulated recycling pathway in metacyclic parasites. Once at the plasma membrane, HASPB18-GFP (green fluorescent protein) can undergo bidirectional movement within the inner leaflet of the membrane and on the flagellum. Transfer of fluorescent protein between the flagellum and the plasma membrane is compromised, however, suggesting the presence of a diffusion barrier at the base of the Leishmania flagellum. Full-length HASPB is released from the metacyclic parasite surface on to macrophages during phagocytosis but while expression is maintained in intracellular amastigotes, HASPB cannot be detected on the external surface in these cells. Thus HASPB may be a dual function protein that is shed by the infective metacyclic but retained internally once Leishmania are taken up by macrophages.

Ultramicroscopy, 2014

In-resin fluorescence Correlative light and electron microscopy Integrated light and electron mic... more In-resin fluorescence Correlative light and electron microscopy Integrated light and electron microscopy a b s t r a c t Fluorescence microscopy of GFP-tagged proteins is a fundamental tool in cell biology, but without seeing the structure of the surrounding cellular space, functional information can be lost. Here we present a protocol that preserves GFP and mCherry fluorescence in mammalian cells embedded in resin with electron contrast to reveal cellular ultrastructure. Ultrathin in-resin fluorescence (IRF) sections were imaged simultaneously for fluorescence and electron signals in an integrated light and scanning electron microscope. We show, for the first time, that GFP is stable and active in resin sections in vacuo. We applied our protocol to study the subcellular localisation of diacylglycerol (DAG), a modulator of membrane morphology and membrane dynamics in nuclear envelope assembly. We show that DAG is localised to the nuclear envelope, nucleoplasmic reticulum and curved tips of the Golgi apparatus. With these developments, we demonstrate that integrated imaging is maturing into a powerful tool for accurate molecular localisation to structure.

Molecular and Biochemical Parasitology, 2010

Here we validate a new method for immobilising the protozoan parasites Trypanosoma brucei and Lei... more Here we validate a new method for immobilising the protozoan parasites Trypanosoma brucei and Leishmania major parasites while maintaining a high level of viability.

Journal of Microscopy, 2009

Biofilms are an important element of the natural ecosystems but can be detrimental in health care... more Biofilms are an important element of the natural ecosystems but can be detrimental in health care and industrial settings. To improve our ability to combat biofilms, we need to understand the processes that facilitate their formation and dispersal. One approach that has proven to be invaluable is to image biofilms as they grow. Here we describe tools and protocols to visualize biofilms with multiphoton laser scanning microscopy, compare this with single photon laser scanning confocal microscopy and highlight best working procedures. Furthermore, we describe how with multiphoton laser scanning microscopy the laser can be used to manipulate the biofilm, specifically to achieve localized bleaching, killing or ablation within the biofilm biomass. These applications open novel ways to study the dynamics of biofilm formation, regeneration and dispersal.