The effect of membrane active agents on human leukaemia cells

This Thesis investigates the effect of membrane-active agents, such as synthetic ether lipids (SEL), local anaesthetics and polyunsaturated fatty acids (PUFAs) on human leukaemia cells. The two cell lines used were human acute myeloblastic leukaemia (HL60) cells and human myelogenous leukaemia (K562) cells. SEL, local anaesthetics and PUFAs were found to be cytotoxic to both cell lines at certain concentrations. The SEL ET-18-OCH(_3) was found to be cytotoxic to both cell lines but the HL60 cells were found to be the more sensitive cell line. HL60 cells were found to be so sensitive to the action of the local anaesthetic dibucaine that a subtoxic concentration that killed ≤10% was not determined. However, in K562 cells the combination of a subtoxic dibucaine concentration together with a range of ET-I8-OCH(_3) concentrations increased the cytotoxicity over that of ether lipid alone. PUFAs were shown to incorporate into plasma membrane phospholipids at concentrations as low as 1 μM after an incubation of 48 hours. PUFAs were shown to be cytotoxic, but the addition of vitamin E reduced the cytotoxicity of arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid in HL60 cells, and of docosahexaenoic acid in K562 cells. This implied that lipid peroxidation was involved in PUFA cytotoxicity. This was, however, not confirmed. PUFA in combination with ET-I8-OCH3 resulted in a slight decrease in cytotoxicity. PUFA combined with dibucaine did not alter cytotoxicity. Cells were also treated with a combination of PUFA and 1-β-D- arabinofliranosylcytosine (ara-C), which is an agent known to induce cell differentiation. Onset of differentiation was determined by following haemoglobin accumulation in K562 cells. PUFA on their own were found to promote accumulation of haemoglobin. The greatest accumulation of haemoglobin was observed with K562 cells treated with PUFA and ara-C

Genetic diversity and virulence variability in Diplodia mutila isolates from symptomatic grapevines in New Zealand: Virulence and genetic diversity of Diplodia mutila

Genetic diversity and virulence variability of Diplodia mutila isolates recovered from grapevines in New Zealand were investigated. The universally primed PCR (UP-PCR) and vegetative compatibility group (VCG) methods were used to investigate the genetic diversity. Pathogenicity tests with ‘Sauvignon Blanc’ detached shoots and potted vines were used to determine the virulence diversity. UP-PCR analysis determined eight genetic groups of D. mutila with 70% of the population within one group. Phylogenetic analysis also determined that New Zealand isolates were more closely related to Australian isolates than Californian isolates. Vegetative compatibility grouping analysis placed the isolates into three VCG groups, with 57% of isolates belonging to all three VCGs. Vegetative compatibility reactions were observed among isolates, but this was not correlated with the genetic clustering. Virulence assays proved that all isolates tested were pathogenic on grapevine stems. Differences in necrotic lesions lengths caused by D. mutila isolates were identified, indicating different virulence levels among isolates, however, no relationship was found between the genetic groups and the virulence. The results of the study indicated movement of D. mutila isolates between nurseries, vineyards, and other sources in New Zealand. This information will inform control strategies to limit the further spread of this pathogen into vineyards in the same region or new regions

Understanding Trichoderma bio-inoculants in the root ecosystem of Pinus radiata

Oral presentation on understanding Trichoderma bio-inoculants in the root ecosystem of Pinus radiat

Propagule and soil type affects the pathogenicity of Ilyonectria and Dactylonectria spp., the causal agents of black foot disease of grapevines

Black foot disease of grapevines is a significant economic issue for the viticulture industry worldwide. The disease is mainly associated with soil borne pathogen species within the genera Dactylonectria and Ilyonectria. The aim of this study was to determine the pathogenicity of different pathogen propagules, including chlamydospores, conidia and mycelium, to grapevine rootstocks grown in soil. A combination of nine isolates belonging to Dactylonectria and Ilyonectria genera, representative of the fungal species associated with black foot disease in New Zealand were used to inoculate grapevines in a field experiment. In the second experiment, the pathogenicity of the different propagules was assessed in different soil types, clay loam, silt loam and sandy loam soils. In the field experiment, chlamydospores and conidia resulted in higher disease incidence and severity at 0 cm above the grapevine stem base compared with mycelium. At 5 cm above the stem base, chlamydospores caused the greatest disease incidence compared with the other two propagules. Propagule type had no effect on shoot and root dry weights. In the pot experiment, soil type affected disease incidence and severity, with clay loam soil resulting in significantly greater disease incidence and severity than silt loam or sandy loam soils. Disease severity at 0 cm above the stem base was significantly higher with conidial inoculations compared with chlamydospore inoculations irrespective of soil type. Root dry weights were also affected with heavier roots from plants grown in sandy loam compared with silt loam and clay loam soils, however, shoot dry weight was greater in clay loam and sandy loam compared with silt loam soils. The results of the study confirmed that all propagule types were able to infect grapevine rootstocks when planted in inoculated soil and showed that although the pathogens were capable of infecting the rootstocks in all soil types, disease level was higher in the heavier clay loam soil. It is therefore recommended that growers either avoid planting in such soils or apply strategies to improve drainage and soil aeration

Use of Coniothyrium minitans transformed with the hygromycin B resistance gene to study survival and infection of Sclerotinia sclerotiorum sclerotia in soil

A Coniothyrium minitans strain (T3) co-transformed with the genes for β-glucuronidase (uidA) and hygromycin phosphotransferase (hph), the latter providing resistance to the antibiotic hygromycin B, was used to investigate the survival and infection of sclerotia of Sclerotinia sclerotiorum by C. minitans over time in four different soils. Infection of sclerotia was rapid in all cases, with the behaviour of transformant T3 and wild type parent A69 being similar. Differences were seen between the soils in the rate of infection of sclerotia by C. minitans and in their indigenous fungal populations. Amendment of agar with hygromycin B enabled the quantification of C. minitans in soil by dilution plating where there was a high background of other microorganisms. In Lincoln soil from New Zealand, which had a natural but low population of C. minitans the hygromycin B resistance marker allowed the umambiguous discrimination of the applied transformed isolate from the indigenous hygromycin B sensitive one. In this soil, although the indigenous C. minitans population was detected from sclerotia, none were recovered on the dilution plates, indicating the increased sensitivity of C. minitans detection from soil using sclerotial baiting. C. minitans was a very efficient parasite, being able to infect a large proportion of sclerotia within a relatively short time from an initially low soil population. The addition of hygromycin B to agar also allowed the detection of C. minitans from decaying sclerotia by inhibiting secondary fungal colonisers. This is the first report to show that fungi colonising sclerotia already infected by C. minitans mask the detection of C. minitans from sclerotia rather than displacing the original parasite

Grapevines escaping trunk diseases in New Zealand vineyards have a distinct microbiome structure

Grapevine trunk diseases (GTDs) are a substantial challenge to viticulture, especially with a lack of available control measures. The lack of approved fungicides necessitates the exploration of alternative controls. One promising approach is the investigation of disease escape plants, which remain healthy under high disease pressure, likely due to their microbiome function. This study explored the microbiome of grapevines with the disease escape phenotype. DNA metabarcoding of the ribosomal internal transcribed spacer 1 (ITS1) and 16S ribosomal RNA gene was applied to trunk tissues of GTD escape and adjacent diseased vines. Our findings showed that the GTD escape vines had a significantly different microbiome compared with diseased vines. The GTD escape vines consistently harbored a higher relative abundance of the bacterial taxa Pseudomonas and Hymenobacter. Among fungi, Aureobasidium and Rhodotorula were differentially associated with GTD escape vines, while the GTD pathogen, Eutypa, was associated with the diseased vines. This is the first report of the link between the GTD escape phenotype and the grapevine microbiome

A new set of international Leptosphaeria maculans isolates as a resource for elucidation of the basis and evolution of blackleg disease on Brassica napus

© 2023 The Authors. Plant Pathology published by John Wiley & Sons Ltd on behalf of British Society for Plant Pathology. This is an open access article under the terms of the Creative Commons Attribution-Non Commercial-No Derivs License. https://creativecommons.org/licenses/by-nc-nd/4.0/A collection of isolates of the fungi Leptosphaeria maculans and L. biglobosa, which cause blackleg disease on Brassica napus (canola/oilseed rape) and other Brassicaceae species, was assembled to represent the global diversity of these pathogens and a resource for international research. The collection consists of 226 isolates (205 L. maculans and 21 L. biglobosa) from 11 countries. The genomes of all 205 L. maculans isolates were sequenced, and the distribution and identity of avirulence gene alleles were determined based on genotypic information and phenotypic reactions on B. napus lines that hosted specific resistance genes. Whilst the frequencies of some avirulence alleles were consistent across each of the regions, others differed dramatically, potentially reflecting the canola/oilseed rape cultivars grown in those countries. Analyses of the single-nucleotide polymorphism (SNP) diversity within these L. maculans isolates revealed geographical separation of the populations. This "open access" resource provides a standardized set of isolates that can be used to define the basis for how these fungal pathogens cause disease, and as a tool for discovery of new resistance traits in Brassica species.Peer reviewe

Impacts of the Covid-19 pandemic on air quality in Wales: March to October 2020

The report covers the WAQF's activity in 2020 and important policy developments since the last report was published in 2020. As usual we review the latest trends in air pollution measurements and implications for policy compliance as well as maps of Air Quality for NO2, O3, PM10 and PM2.5 in 2020. The area of special interest this year looks at the Landmark Second Inquest Rules that Air Pollution Contributed to the Death in London of 9-Year Old, Ella Adoo-Kissi-Debrah. The health chapter provides a review of Air Quality and Public Health in 2020

Arolwg o'r canu i deulu Mostyn, ynghyd â golygiad o'r cerddi o'r cyfnod c.1675-1692

Bu teulu Mostyn yn gefnogol i’r traddodiad barddol yn eu pum llys ar draws gogledd Cymru am ganrifoedd, a chlodforir eu nawdd yng nghanu beirdd y cyfnod. Daeth penllanw’r nawdd barddol yn yr 16g, yn arbennig drwy’r cysylltiad agos rhwng y teulu ac Eisteddfodau Caerwys 1523 a 1567/8. Erbyn cyfnod y Rhyfel Cartref, fodd bynnag, roedd y canu wedi dirwyn i ben ar aelwydydd y teulu. Mae’r rhagymadrodd yn astudiaeth o hanes teulu Mostyn o’r pum llys hyd at 1847, a cheir dyfyniadau o rai o’r cerddi a ganwyd ar eu haelwydydd dros y canrifoedd. Ond ar ddiddordeb Tomas Mostyn (m.1692) mewn casgliadau llenyddol a nawdd barddol yn chwarter olaf yr 17g. y mae prif sylw’r traethawd hwn a chyflwynir golygiad o’r cerddi a ganwyd iddo ef a’i deulu fel tystiolaeth o’i waith yn atgyfodi’r traddodiad barddol ar aelwyd y teulu unwaith eto. Rhoddir sylw hefyd yn y rhagymadrodd i gefndir ei wraig, Bridget Savage, a dylanwad y ffydd Babyddol ar dynged ei theulu. Ceir gwybodaeth hefyd am gysylltiad y teulu â’r drefn farddol hyd at y 19g. i gloi’r rhagymadrodd