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Search Results: 1 - 10 of 6110 matches for " Ian Goodhead "
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ApiAP2 Factors as Candidate Regulators of Stochastic Commitment to Merozoite Production in Theileria annulata
Marta Pieszko?,William Weir?,Ian Goodhead,Jane Kinnaird?,Brian Shiels
PLOS Neglected Tropical Diseases , 2015, DOI: 10.1371/journal.pntd.0003933
Abstract: Background Differentiation of one life-cycle stage to the next is critical for survival and transmission of apicomplexan parasites. A number of studies have shown that stage differentiation is a stochastic process and is associated with a point that commits the cell to a change over in the pattern of gene expression. Studies on differentiation to merozoite production (merogony) in T. annulata postulated that commitment involves a concentration threshold of DNA binding proteins and an auto-regulatory loop. Principal Findings In this study ApiAP2 DNA binding proteins that show changes in expression level during merogony of T. annulata have been identified. DNA motifs bound by orthologous domains in Plasmodium were found to be enriched in upstream regions of stage-regulated T. annulata genes and validated as targets for the T. annulata AP2 domains by electrophoretic mobility shift assay (EMSA). Two findings were of particular note: the gene in T. annulata encoding the orthologue of the ApiAP2 domain in the AP2-G factor that commits Plasmodium to gametocyte production, has an expression profile indicating involvement in transmission of T. annulata to the tick vector; genes encoding related domains that bind, or are predicted to bind, sequence motifs of the type 5'-(A)CACAC(A) are implicated in differential regulation of gene expression, with one gene (TA11145) likely to be preferentially up-regulated via auto-regulation as the cell progresses to merogony. Conclusions We postulate that the Theileria factor possessing the AP2 domain orthologous to that of Plasmodium AP2-G may regulate gametocytogenesis in a similar manner to AP2-G. In addition, paralogous ApiAP2 factors that recognise 5'-(A)CACAC(A) type motifs could operate in a competitive manner to promote reversible progression towards the point that commits the cell to undergo merogony. Factors possessing AP2 domains that bind (or are predicted to bind) this motif are present in the vector-borne genera Theileria, Babesia and Plasmodium, and other Apicomplexa; leading to the proposal that the mechanisms that control stage differentiation will show a degree of conservation.
A Novel Linear Plasmid Mediates Flagellar Variation in Salmonella Typhi
Stephen Baker ,Jonathan Hardy,Kenneth E Sanderson,Michael Quail,Ian Goodhead,Robert A Kingsley,Julian Parkhill,Bruce Stocker ?,Gordon Dougan
PLOS Pathogens , 2007, DOI: 10.1371/journal.ppat.0030059
Abstract: Unlike the majority of Salmonella enterica serovars, Salmonella Typhi (S. Typhi), the etiological agent of human typhoid, is monophasic. S. Typhi normally harbours only the phase 1 flagellin gene (fliC), which encodes the H:d antigen. However, some S. Typhi strains found in Indonesia express an additional flagellin antigen termed H:z66. Molecular analysis of H:z66+ S. Typhi revealed that the H:z66 flagellin structural gene (fljBz66) is encoded on a linear plasmid that we have named pBSSB1. The DNA sequence of pBSSB1 was determined to be just over 27 kbp, and was predicted to encode 33 coding sequences. To our knowledge, pBSSB1 is the first non-bacteriophage–related linear plasmid to be described in the Enterobacteriaceae.
Adsorption of Acetic Acid, Cadmium ions, Lead ions and Iodine Using Activated Carbon from Waste Wood and Rice Husks
TO Goodhead, KK Dagde
Journal of Applied Sciences and Environmental Management , 2011,
Abstract: This paper presents the performance evaluation of locally prepared activated carbon from rice husk and saw dust. The raw materials were carbonized at different temperatures (600-800oC) using sodium hydroxide (NaOH) as the activating agent. The study includes moisture content determination of the raw materials used in the activation and carbonization processes. The effects of variations in carbonization temperature and concentration of activating agent on various performance indices for good quality absorbent were investigated. The percentage yield of the activated carbon from the raw materials as well as iodine number and adsorption of heavy metals from aqueous solutions were also determined. The experimental data which make a comparative assessment of activated carbon obtained from rice husk and saw dust were also presented. Preliminary examination of the raw materials showed that rice husk and saw dust had a moisture content of 14.6% and 5.8% respectively. Increase in carbonization temperature decreases yield of the active carbon. The highest yield of about 48% was obtained from rice husk at 600oC, with moisture content of 26%. The rice husk at 800oC gave a yield of 47.2% with moisture content of 26.5%. Whilst the yield of the saw dust was 44% at 600oC and 40% at 800oC with moisture content of 17% and 19% respectively. A detailed study of mass transfer processes indicated that activated carbon from these materials show good performance.
A Comprehensive Genetic Analysis of Candidate Genes Regulating Response to Trypanosoma congolense Infection in Mice
Ian Goodhead,Alan Archibald,Peris Amwayi,Andy Brass,John Gibson,Neil Hall,Margaret A. Hughes,Moses Limo,Fuad Iraqi,Stephen J. Kemp,Harry A. Noyes
PLOS Neglected Tropical Diseases , 2010, DOI: 10.1371/journal.pntd.0000880
Abstract: Background African trypanosomes are protozoan parasites that cause “sleeping sickness” in humans and a similar disease in livestock. Trypanosomes also infect laboratory mice and three major quantitative trait loci (QTL) that regulate survival time after infection with T. congolense have been identified in two independent crosses between susceptible A/J and BALB/c mice, and the resistant C57BL/6. These were designated Tir1, Tir2 and Tir3 for Trypanosoma infection response, and range in size from 0.9–12 cM. Principal Findings Mapping loci regulating survival time after T. congolense infection in an additional cross revealed that susceptible C3H/HeJ mice have alleles that reduce survival time after infection at Tir1 and Tir3 QTL, but not at Tir2. Next-generation resequencing of a 6.2 Mbp region of mouse chromosome 17, which includes Tir1, identified 1,632 common single nucleotide polymorphisms (SNP) including a probably damaging non-synonymous SNP in Pram1 (PML-RAR alpha-regulated adaptor molecule 1), which was the most plausible candidate QTL gene in Tir1. Genome-wide comparative genomic hybridisation identified 12 loci with copy number variants (CNV) that correlate with differential gene expression, including Cd244 (natural killer cell receptor 2B4), which lies close to the peak of Tir3c and has gene expression that correlates with CNV and phenotype, making it a strong candidate QTL gene at this locus. Conclusions By systematically combining next-generation DNA capture and sequencing, array-based comparative genomic hybridisation (aCGH), gene expression data and SNP annotation we have developed a strategy that can generate a short list of polymorphisms in candidate QTL genes that can be functionally tested.
Identification of a Mutation Associated with Fatal Foal Immunodeficiency Syndrome in the Fell and Dales Pony
Laura Y. Fox-Clipsham,Stuart D. Carter,Ian Goodhead,Neil Hall,Derek C. Knottenbelt,Paul D. F. May,William E. Ollier,June E. Swinburne
PLOS Genetics , 2011, DOI: 10.1371/journal.pgen.1002133
Abstract: The Fell and Dales are rare native UK pony breeds at risk due to falling numbers, in-breeding, and inherited disease. Specifically, the lethal Mendelian recessive disease Foal Immunodeficiency Syndrome (FIS), which manifests as B-lymphocyte immunodeficiency and progressive anemia, is a substantial threat. A significant percentage (~10%) of the Fell ponies born each year dies from FIS, compromising the long-term survival of this breed. Moreover, the likely spread of FIS into other breeds is of major concern. Indeed, FIS was identified in the Dales pony, a related breed, during the course of this work. Using a stepwise approach comprising linkage and homozygosity mapping followed by haplotype analysis, we mapped the mutation using 14 FIS–affected, 17 obligate carriers, and 10 adults of unknown carrier status to a ~1 Mb region (29.8 – 30.8 Mb) on chromosome (ECA) 26. A subsequent genome-wide association study identified two SNPs on ECA26 that showed genome-wide significance after Bonferroni correction for multiple testing: BIEC2-692674 at 29.804 Mb and BIEC2-693138 at 32.19 Mb. The associated region spanned 2.6 Mb from ~29.6 Mb to 32.2 Mb on ECA26. Re-sequencing of this region identified a mutation in the sodium/myo-inositol cotransporter gene (SLC5A3); this causes a P446L substitution in the protein. This gene plays a crucial role in the regulatory response to osmotic stress that is essential in many tissues including lymphoid tissues and during early embryonic development. We propose that the amino acid substitution we identify here alters the function of SLC5A3, leading to erythropoiesis failure and compromise of the immune system. FIS is of significant biological interest as it is unique and is caused by a gene not previously associated with a mammalian disease. Having identified the associated gene, we are now able to eradicate FIS from equine populations by informed selective breeding.
Multiple eyelid apocrine hidrocystoma in a domestic short-haired cat : clinical communication
A. Sivagurunathan,A. D. Goodhead,E. C. Du Plessis
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v81i1.100
Abstract: A 12-year-old domestic short-haired cat was referred for evaluation of periocular masses. The tail had similar masses and was amputated previously by the referring veterinarian. On examination, multiple pigmented nodules, 3-15 mm in diameter, were found in the periocular skin, primarily involving the palpebral eyelid margin. A wedge excisional biopsy revealed small cuboidal cells forming multiple tubular and cystic structures indicative of apocrine cystadenomas, similar to apocrine hidrocystomas described in humans. The nodules were lanced followed by liquid nitrogen cryofreezing.
Telomeric Expression Sites Are Highly Conserved in Trypanosoma brucei
Christiane Hertz-Fowler, Luisa M. Figueiredo, Michael A. Quail, Marion Becker, Andrew Jackson, Nathalie Bason, Karen Brooks, Carol Churcher, Samah Fahkro, Ian Goodhead, Paul Heath, Magdalena Kartvelishvili, Karen Mungall, David Harris, Heidi Hauser, Mandy Sanders, David Saunders, Kathy Seeger, Sarah Sharp, Jesse E. Taylor, Danielle Walker, Brian White, Rosanna Young, George A. M. Cross, Gloria Rudenko, J. David Barry, Edward J. Louis, Matthew Berriman
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003527
Abstract: Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs) of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs). The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs) were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology.
Commodity Currency: An Alternative Route to Currency Union  [PDF]
Ian McFarlane
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.32019
Abstract: Proposals have been made for a common currency for East Asia, but the countries preparing to participate need to be in a state of economic convergence. We show that at least six countries of East Asia already satisfy this condition. There also needs to be a mechanism by which the new currency relates to other reserve currencies. We demonstrate that a numéraire could be defined solely from the actual worldwide consumption of food and energy per capita, linked to fiat currencies via world market prices. We show that real resource prices are stable in real terms, and likely to remain so. Furthermore, the link from energy prices to food commodity prices is permanent, arising from energy inputs in agriculture, food processing and distribution. Calibration of currency value using a yardstick such as our SI numéraire offers an unbiased measure of the consistently stable cost of subsistence in the face of volatile currency exchange rates. This has the advantage that the participating countries need only agree to currency governance based on a common standards institution, a much less onerous form of agreement than would be required in the creation of a common central bank.
Agricultural Commodity Markets: Reference Point for the Real Value of a Currency  [PDF]
Ian McFarlane
Modern Economy (ME) , 2014, DOI: 10.4236/me.2014.55050
Abstract:

Using monthly time-series data 1999-2013, the paper shows that markets for agricultural commodities provide a yardstick for real purchasing power, and thus a reference point for the real value of fiat currencies. The daily need for each adult to consume about 2800 food calories is universal; data from FAO food balance sheets confirm that the world basket of food consumed daily is non-volatile in comparison to the volatility of currency exchange rates, and so the replacement cost of food consumed provides a consistent indicator of economic value. Food commodities are storable for short periods, but ultimately perishable, and this exerts continual pressure for markets to clear in the short term; moreover, food calories can be obtained from a very large range of foodstuffs, and so most households are able to use arbitrage to select a near optimal weighting of quantities purchased. The paper proposes an original method to enable a standard of value to be established, definable in physical units on the basis of actual worldwide consumption of food goods, with an illustration of the method.

The diagnosis and management of snakebite in dogs - a southern African perspective : review article
A.L. Leisewitz,R.S. Blaylock,F. Kettner,A. Goodhead
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v75i1.441
Abstract: Cases of snakebite envenomation are frequently presented to veterinary practitioners in southernAfrica. Despite this, no published guidelines exist onhowthis medical emergency should be managed. Southern African snake venoms can be classified into 3 main types based on the main mechanism of venom action and clinical presentation. A polyvalent antivenom is manufactured in South Africa and contains antibodies against the most important southern African snake venoms. The cytotoxic venoms are represented mainly by the puff-adder (Bitis arietans), Mozambique spitting cobra (Naja mossabica), black-necked spitting cobra (Naja nigricollis) (in the Western Cape and Namibia) and the stiletto snake (Atractaspis bibronii). These venoms may cause dramatic local swelling, high morbidity and low mortality and infrequently require the use of antivenom for survival (the only cytotoxic venoms used to prepare the antivenom are the puff-adder and Mozambique spitting cobra). The neurotoxic venoms (represented chiefly by the non-spitting cobras and mambas) cause high mortality due to rapid onset of paresis and require antivenom and mechanical ventilatory support which is life-saving. The boomslang (Dispholidus typus) and the vine snake (coagulopathic venom) rarely bite humans but dogs may be bitten more frequently. These venoms cause a consumption coagulopathy and successful treatment of boomslang bites requires the use of snake species-specific monovalent antivenom. There is no antivenom available for treating vine snake (Thelotornis capensis), berg adder (Bitis atropos), night adder (Causus spp.), stiletto snake and other lesser adder bites. There are some important differences between the way snakebites are managed in humans and dogs.
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