• Bile UPLC-MS fingerprinting and bile acid fluxes during human liver transplantation

      Legido-Quigley, Cristina; McDermott, Lindsay C.; Vilca-Melendez, Hector; Murphy, Gerard M.; Heaton, Nigel; Lindon, John C.; Nicholson, Jeremy K.; Holmes, Elaine (Wiley, 2011-07-06)
      Bile flow restoration is a crucial step in the recovery process post transplantation of the liver. Here, metabolic trajectories based on changes in bile secretion – a known marker of functionality – have been utilised as an approach for discovering bile fluxes during transplantation. A total of ten liver transplants were monitored and from these 68 bile samples from both donors and recipients were collected and analysed using ultra‐performance LC‐MS in combination with multivariate statistical analysis. Based on the principal component scores constructed from the total bile fingerprint, differentiation of the bile acid concentrations before and after transplantation was detected. A trend was also observed, by constructing metabolic trajectories, whereby the post‐transplant profiles approached the position of pre‐transplant profiles within 30–60 min of the restoration of bile secretion function. The ten major conjugated bile acid salts were measured and a significant increase in concentrations of taurocholic acid and taurochenodeoxycholic acid were seen after transplantation. In addition, the ratios of secondary bile acids detected in gall bladder and hepatic bile were measured before and after transplantation. This study suggests that bile acid ratios in the donor liver at the pre‐transplant and post‐transplant stage may be important and that profiling of secreted bile after transplantation may aid clinical assessment and progress post‐transplantation.
    • Bovine milk fat globule epidermal growth factor Ⅷ activates PI3K/Akt signaling pathway and attenuates sarcopenia in rat model induced by D-galactose

      Li, He; Wang, Rongchun; Wang, Lifeng; Li, Lin; Ma, Ying; Zhou, Shaobo; Jiangsu Normal University; Harbin Institute of Technology; Northeast Agriculture University; University of Bedfordshire (Elsevier, 2020-12-17)
      To develop a more effective and safer treatment for sarcopenia, this research investigated the anti-sarcopenia mechanism of Milk Fat Globule Epidermal Growth Factor Ⅷ (MFG-E8) from the liver function and metabolism in sarcopenic model rat. After 4 weeks nutritional intervention experiment, MFG-E8 can significantly increase the gastrocnemius mass in rat. The mechanism of MFG-E8 in improving sarcopenia was related to its promotional capacity to the activities of superoxide dismutase (SOD) activity in serum, Glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in liver. Meanwhile, MFG-E8 could also down-regulate obesity-related indicators, such as triglyceride (TG) and Non-esterified fatty acid (NEFA). The analysis of liver and gastrocnemius histopathology found that MFG-E8 could reduce the accumulation of fatty vesicles, improve liver function, thereby alleviating gastrocnemius tissue inflammation. In vitro experiments, myoblasts obtained from gastrocnemius tissue showed that MFG-E8 could reduce mitochondrial autophagy and inhibit cell apoptosis. In addition, MFG-E8 could up-regulate the phosphorylation level of PI3K via activating PI3K/Akt signaling pathway in gastrocnemius tissue, and promote the formation of muscle fibers, thereby increasing muscle mass. Moreover, MFG-E8 could also promote the formation of neuromuscular junctions by up-regulating the mRNA and protein expression of MusK in gastrocnemius.
    • BU08073 a buprenorphine analogue with partial agonist activity at μ-receptors in vitro but long-lasting opioid antagonist activity in vivo in mice

      Khroyan, Taline V.; Wu, J.; Polgar, Willma E.; Cami-Kobeci, Gerta; Fotaki, N.; Husbands, Stephen M.; Toll, Lawrence; (John Wiley and Sons Inc., 2014-11-05)
      Background and Purpose Buprenorphine is a potent analgesic with high affinity at μ, δ and κ and moderate affinity at nociceptin opioid (NOP) receptors. Nevertheless, NOP receptor activation modulates the in vivo activity of buprenorphine. Structure activity studies were conducted to design buprenorphine analogues with high affinity at each of these receptors and to characterize them in in vitro and in vivo assays. Experimental Approach Compounds were tested for binding affinity and functional activity using [35S]GTPγS binding at each receptor and a whole‐cell fluorescent assay at μ receptors. BU08073 was evaluated for antinociceptive agonist and antagonist activity and for its effects on anxiety in mice. Key Results BU08073 bound with high affinity to all opioid receptors. It had virtually no efficacy at δ, κ and NOP receptors, whereas at μ receptors, BU08073 has similar efficacy as buprenorphine in both functional assays. Alone, BU08073 has anxiogenic activity and produces very little antinociception. However, BU08073 blocks morphine and U50,488‐mediated antinociception. This blockade was not evident at 1 h post‐treatment, but is present at 6 h and remains for up to 3–6 days. Conclusions and Implications These studies provide structural requirements for synthesis of ‘universal’ opioid ligands. BU08073 had high affinity for all the opioid receptors, with moderate efficacy at μ receptors and reduced efficacy at NOP receptors, a profile suggesting potential analgesic activity. However, in vivo, BU08073 had long‐lasting antagonist activity, indicating that its pharmacokinetics determined both the time course of its effects and what receptor‐mediated effects were observed.
    • BU10038 as a safe opioid analgesic with fewer side-effects after systemic and intrathecal administration in primates

      Kiguchi, Norikazu; Ding, Huiping; Cami-Kobeci, Gerta; Sukhtankar, Devki D.; Czoty, Paul W.; DeLoid, Heather B.; Hsu, Fang-Chi; Toll, Lawrence; Husbands, Stephen M.; Ko, Mei-Chuan; et al. (Elsevier Ltd, 2019-03-01)
      Background: The marked increase in mis-use of prescription opioids has greatly affected our society. One potential solution is to develop improved analgesics which have agonist action at both mu opioid peptide (MOP) and nociceptin/orphanin FQ peptide (NOP) receptors. BU10038 is a recently identified bifunctional MOP/NOP partial agonist. The aim of this study was to determine the functional profile of systemic or spinal delivery of BU10038 in primates after acute and chronic administration. Methods: A series of behavioural and physiological assays have been established specifically to reflect the therapeutic (analgesia) and side-effects (abuse potential, respiratory depression, itch, physical dependence, and tolerance) of opioid analgesics in rhesus monkeys. Results: After systemic administration, BU10038 (0.001–0.01 mg kg−1) dose-dependently produced long-lasting antinociceptive and antihypersensitive effects. Unlike the MOP agonist oxycodone, BU10038 lacked reinforcing effects (i.e. little or no abuse liability), and BU10038 did not compromise the physiological functions of primates including respiration, cardiovascular activities, and body temperature at antinociceptive doses and a 10–30-fold higher dose (0.01–0.1 mg kg−1). After intrathecal administration, BU10038 (3 μg) exerted morphine-comparable antinociception and antihypersensitivity without itch scratching responses. Unlike morphine, BU10038 did not cause the development of physical dependence and tolerance after repeated and chronic administration. Conclusions: These in vivo findings demonstrate the translational potential of bifunctional MOP/NOP receptor agonists such as BU10038 as a safe, non-addictive analgesic with fewer side-effects in primates. This study strongly supports that bifunctional MOP/NOP agonists may provide improved analgesics and an alternative solution for the ongoing prescription opioid crisis.
    • The cAMP pathway is important for controlling the morphological switch to the pathogenic yeast form of Paracoccidioides brasiliensis.

      Chen, Daliang; Janganan, Thamarai K.; Chen, Gongyou; Marques, Everaldo R.; Kress, Marcia R.; Goldman, Gustavo H.; Walmsley, Adrian R.; Borges-Walmsley, Maria Ines; University of Durham; Universidade de Sao Paulo (Wiley, 2007-08-30)
      Paracoccidioides brasiliensis is a human pathogenic fungus that switches from a saprobic mycelium to a pathogenic yeast. Consistent with the morphological transition being regulated by the cAMP-signalling pathway, there is an increase in cellular cAMP levels both transiently at the onset (< 24 h) and progressively in the later stages (> 120 h) of the transition to the yeast form, and this transition can be modulated by exogenous cAMP. We have cloned the cyr1 gene encoding adenylate cyclase (AC) and established that its transcript levels correlate with cAMP levels. In addition, we have cloned the genes encoding three Galpha (Gpa1-3), Gbeta (Gpb1) and Ggamma (Gpg1) G proteins. Gpa1 and Gpb1 interact with one another and the N-terminus of AC, but neither Gpa2 nor Gpa3 interacted with Gpb1 or AC. The interaction of Gpa1 with Gpb1 was blocked by GTP, but its interaction with AC was independent of bound nucleotide. The transcript levels for gpa1, gpb1 and gpg1 were similar in mycelium, but there was a transient excess of gpb1 during the transition, and an excess of gpa1 in yeast. We have interpreted our findings in terms of a novel signalling mechanism in which the activity of AC is differentially modulated by Gpa1 and Gpb1 to maintain the signal over the 10 days needed for the morphological switch.
    • Cellular mechanisms governing glucose-dependent insulinotropic polypeptide secretion.

      Reimann, Frank; Diakogiannaki, Eleftheria; Moss, Catherine E.; Gribble, Fiona M.; Wellcome Trust; University of Cambridge (Elsevier, 2020-11-19)
      Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone secreted from the upper small intestine, which plays an important physiological role in the control of glucose metabolism through its incretin action to enhance glucose-dependent insulin secretion. GIP has also been implicated in postprandial lipid homeostasis. GIP is secreted from enteroendocrine K-cells residing in the intestinal epithelium. K-cells sense a variety of components found in the gut lumen following food consumption, resulting in an increase in plasma GIP signal dependent on the nature and quantity of ingested nutrients. We review the evidence for an important role of sodium-coupled glucose uptake through SGLT1 for carbohydrate sensing, of free-fatty acid receptors FFAR1/FFAR4 and the monoacyl-glycerol sensing receptor GPR119 for lipid detection, of the calcium-sensing receptor CASR and GPR142 for protein sensing, and additional modulation by neurotransmitters such as somatostatin and galanin. These pathways have been identified through combinations of in vivo, in vitro and molecular approaches.
    • Changes of synovial fluid protein concentrations in supra-patellar bursitis patients after the injection of different molecular weights of hyaluronic acid

      Chen, Carl P.C.; Hsu, Chin Chin; Pei, Yu-Cheng; Chen, Ruoli; Zhou, Shaobo; Shen, Hsuan-Chen; Lin, Shih-Cherng; Tsai, Wen-Chung; ; Chang Gung University; et al. (Elsevier, 2014-01-30)
      Knee pain is commonly seen in orthopedic and rehabilitation outpatient clinical settings, and in the aging population. Bursitis of the knee joint, especially when the volume of the synovial fluid is large enough, can compress and distend the nearby soft tissues, causing pain in the knee joint. Out of all the bursae surrounding the knee joint, supra-patellar bursitis is most often associated with knee pain. Treatment strategies in managing supra-patellar bursitis include the aspiration of joint synovial fluid and then followed by steroid injection into the bursa. When supra-patellar bursitis is caused by degenerative disorders, the concept of viscosupplementation treatment may be effective by injecting hyaluronic acid into the bursa. However, the rheology or the changes in the concentrations of proteins (biomarkers) that are related to the development of bursitis in the synovial fluid is virtually unexplored. Therefore, this study aimed to identify the concentration changes in the synovial fluid total protein amount and individual proteins associated with supra-patellar bursitis using the Bradford protein assay and western immunoglobulin methods. A total of 20 patients were divided into two groups with 10 patients in each group. One group received the high molecular weight hyaluronic acid product of Synvisc Hylan G-F 20 and the other group received the low molecular weight hyaluronic acid product of Hya-Joint Synovial Fluid Supplement once per week injection into the bursa for a total of 3. weeks. Significant decreases in the synovial fluid total protein concentrations were observed after the second dosage of high molecular weight hyaluronic acid injections. Apolipoprotein A-I, interleukin 1 beta, alpha 1 antitrypsin, and matrix metalloproteinase 1 proteins revealed a trend of decreasing western immunoblotting band densities after hyaluronic acid injections. The decreases in apolipoprotein A-I and interleukin 1 beta protein band densities were significant in the high molecular weight hyaluronic acid injection group. Transthyretin, complement 5, and matrilin 3 proteins revealed a trend of increasing western immunoblotting band densities after hyaluronic acid injections. Transthyretin revealed significant increases in protein band densities in both the high and low molecular weight hyaluronic acid injection groups. This study may provide the rationale for targeting several biomarkers associated with lipid transport, inflammation, and anti-aging as possible disease modifying therapies for the treatment of supra-patellar bursitis and even degenerative joint disorders. © 2014 Elsevier B.V.
    • Characterisation of hepcidin response to holotransferrin treatment in CHO TRVb-1 cells

      Mehta, Kosha; Greenwell, Pamela; Renshaw, Derek; Busbridge, Mark; Garcia, Mitla; Farnaud, Sébastien; Patel, Vinood B.; University of Westminster; Coventry University; Imperial College Healthcare NHS Trust; et al. (Elsevier, 2015-08-28)
      Iron overload coupled with low hepcidin levels are characteristics of hereditary haemochromatosis. To understand the role of transferrin receptor (TFR) and intracellular iron in hepcidin secretion, Chinese hamster ovary transferrin receptor variant (CHO TRVb-1) cells were used that express iron-response-element-depleted human TFRC mRNA (TFRC∆IRE). Results showed that CHO TRVb-1 cells expressed higher basal levels of cell-surface TFR1 than HepG2 cells (2.2-fold; p < 0.01) and following 5 g/L holotransferrin treatment maintained constitutive over-expression at 24h and 48 h, contrasting the HepG2 cells where the receptor levels significantly declined. Despite this, the intracellular iron content was neither higher than HepG2 cells nor increased over time under basal or holotransferrin-treated conditions. Interestingly, hepcidin secretion in CHO TRVb-1 cells exceeded basal levels at all time-points (p < 0.02) and matched levels in HepG2 cells following treatment. While TFRC mRNA expression showed expected elevation (2h, p < 0.03; 4h; p < 0.05), slc40a1 mRNA expression was also elevated (2 h, p < 0.05; 4 h, p < 0.03), unlike the HepG2 cells. In conclusion, the CHO TRVb-1 cells prevented cellular iron-overload by elevating slc40a1 expression, thereby highlighting its significance in the absence of iron-regulated TFRC mRNA. Furthermore, hepcidin response to holotransferrin treatment was similar to HepG2 cells and resembled the human physiological response.
    • Characterization of a two-component signal transduction system that controls arsenite oxidation in the chemolithoautotroph NT-26

      Sardiwal, Sunita; Santini, Joanne M.; Osborne, Thomas H.; Djordjevic, Snezana; University College London (Wiley, 2010-10-07)
      NT-26 is a chemolithoautotrophic arsenite oxidizer. Understanding the mechanisms of arsenite signalling, tolerance and oxidation by NT-26 will have significant implications for its use in bioremediation and arsenite sensing. We have identified the histidine kinase (AroS) and the cognate response regulator (AroR) involved in the arsenite-dependent transcriptional regulation of the arsenite oxidase aroBA operon. AroS contains a single periplasmic sensory domain that is linked through transmembrane helices to the HAMP domain that transmits the signal to the kinase core of the protein. AroR belongs to a family of AAA+ transcription regulators that interact with DNA through a helix-turn-helix domain. The presence of the AAA+ domain as well as the RNA polymerase σ(54) -interaction sequence motif suggests that this protein regulates transcription through interaction with RNA polymerase in a σ(54) -dependent fashion. The kinase core of AroS and the receiver domain of AroR were heterologously expressed and purified and their autophosphorylation and transphosphorylation activities were confirmed. Using site-directed mutagenesis, we have identified the phosphorylation sites on both proteins. Mutational analysis in NT-26 confirmed that both proteins are essential for arsenite oxidation and the AroS mutant affected growth with arsenite, also implicating it in the regulation of arsenite tolerance. Lastly, arsenite sensing does not appear to involve thiol chemistry.
    • Characterization of Colletotrichum gloeosporioides, as the main causal agent of citrus anthracnose, and C. karstii as species preferentially associated with lemon twig dieback in Portugal

      Ramos, Ana Paula; Talhinhas, Pedro; Sreenivasaprasad, Surapareddy; Oliveira, Helena (Springer Netherlands, 2016-09-13)
      In the last two decades significant losses in citrus production in Portugal related to anthracnose symptoms have been recorded. These symptoms were attributed to Colletotrichum gloeosporioides, but preliminary population diversity evidence suggested that other Colletotrichum species could be involved in the disease. In this work, a field survey of the main citrus growing areas in Portugal was conducted and the pathogenicity of a group of Colletotrichum spp. isolates was studied along with morphological and genetic variability characterization [including Inter-Simple Sequence Repeats (ISSR) profiles and DNA sequence data of rDNA-ITS and β-tubulin 2 gene regions]. Colletotrichum karstii (from the C. boninense species complex) and C. gloeosporioides were identified from symptoms on leaves, branches, flowers and fruits of several citrus cultivars. However, C. acutatum, the species most commonly associated with citrus anthracnose in the Americas, was never detected. While C. gloeosporioides was isolated at higher frequency overall (87 %), C. karstii was more frequent in branches and leaves of lemon in specific geographic locations. Only C. gloeosporioides was detected in flowers. Colletotrichum karstii and C. gloeosporioides were pathogenic to sweet orange flowers and fruits and to leaves of sweet orange, mandarin and lemon, while reference C. acutatum citrus isolates were pathogenic to Key lime flowers and leaves.
    • Characterization of hepcidin response to holotransferrin in novel recombinant TfR1 HepG2 cells

      Mehta, Kosha; Busbridge, Mark; Renshaw, Derek; Evans, Robert W.; Farnaud, Sébastien; Patel, Vinood B.; University of Westminster; Imperial College Healthcare NHS Trust; Coventry University; Brunel University; et al. (Elsevier, 2016-06-30)
      Hepcidin is the key regulator of systemic iron homeostasis. The iron-sensing mechanisms and the role of intracellular iron in modulating hepatic hepcidin secretion are unclear. Therefore, we created a novel cell line, recombinant-TfR1 HepG2, expressing iron-response-element-independent TFRC mRNA to promote cellular iron-overload and examined the effect of excess holotransferrin (5g/L) on cell-surface TfR1, iron content, hepcidin secretion and mRNA expressions of TFRC, HAMP, SLC40A1, HFE and TFR2. Results showed that the recombinant cells exceeded levels of cell-surface TfR1 in wild-type cells under basal (2.8-fold; p<0.03) and holotransferrin-supplemented conditions for 24h and 48h (4.4- and 7.5-fold, respectively; p<0.01). Also, these cells showed higher intracellular iron content than wild-type cells under basal (3-fold; p<0.03) and holotransferrin-supplemented conditions (6.6-fold at 4h; p<0.01). However, hepcidin secretion was not higher than wild-type cells. Moreover, holotransferrin treatment to recombinant cells did not elevate HAMP responses compared to untreated or wild-type cells. In conclusion, increased intracellular iron content in recombinant cells did not increase hepcidin responses compared to wild-type cells, resembling hemochromatosis. Furthermore, TFR2 expression altered within 4h of treatment, while HFE expression altered later at 24h and 48h, suggesting that TFR2 may function prior to HFE in HAMP regulation.
    • Characterization of Linaria KNOX genes suggests a role in petal-spur development

      Box, Mathew S.; Dodsworth, Steven; Rudall, Paula J.; Bateman, Richard M.; Glover, Beverley J. (Wiley, 2011-07-25)
      Spurs are tubular outgrowths of perianth organs that have evolved iteratively among angiosperms. They typically contain nectar and often strongly influence pollinator specificity, potentially mediating reproductive isolation. The identification of Antirrhinum majus mutants with ectopic petal spurs suggested that petal-spur development is dependent on the expression of KNOTTED 1-like homeobox (KNOX) genes, which are better known for their role in maintaining the shoot apical meristem. Here, we tested the role of KNOX genes in petal spur development by isolating orthologs of the A. majus KNOX genes Hirzina (AmHirz) and Invaginata (AmIna) from Linaria vulgaris, a related species that differs from A. majus in possessing long, narrow petal spurs. We name these genes LvHirz and LvIna, respectively. Using quantitative reverse-transcription PCR, we show that LvHirz is expressed at high levels in the developing petals and demonstrate that the expression of petal associated KNOX genes is sufficient to induce sac-like outgrowths on petals in a heterologous host. We propose a model in which KNOX gene expression during early petal-spur development promotes and maintains further morphogenetic potential of the petal, as previously described for KNOX gene function in compound leaf development. These data indicate that petal spurs could have evolved by changes in regulatory gene expression that cause rapid and potentially saltational phenotypic modifications. Given the morphological similarity of spur ontogeny in distantly related taxa, changes in KNOX gene expression patterns could be a shared feature of spur development in angiosperms.
    • Characterization of the spore surface and exosporium proteins of Clostridium sporogenes; implications for Clostridium botulinum group I strains.

      Janganan, Thamarai K.; Mullin, Nic; Tzokov, Svetomir B.; Stringer, Sandra; Fagan, Robert P.; Hobbs, Jamie K.; Moir, Anne; Bullough, Per A.; Institute of Food Research; University of Sheffield (Elsevier, 2016-06-06)
      Clostridium sporogenes is a non-pathogenic close relative and surrogate for Group I (proteolytic) neurotoxin-producing Clostridium botulinum strains. The exosporium, the sac-like outermost layer of spores of these species, is likely to contribute to adhesion, dissemination, and virulence. A paracrystalline array, hairy nap, and several appendages were detected in the exosporium of C. sporogenes strain NCIMB 701792 by EM and AFM. The protein composition of purified exosporium was explored by LC-MS/MS of tryptic peptides from major individual SDS-PAGE-separated protein bands, and from bulk exosporium. Two high molecular weight protein bands both contained the same protein with a collagen-like repeat domain, the probable constituent of the hairy nap, as well as cysteine-rich proteins CsxA and CsxB. A third cysteine-rich protein (CsxC) was also identified. These three proteins are also encoded in C. botulinum Prevot 594, and homologues (75-100% amino acid identity) are encoded in many other Group I strains. This work provides the first insight into the likely composition and organization of the exosporium of Group I C. botulinum spores.
    • cis-(Benzenethiolato)bis(tert-butyl isocyanide)carbonyl(cyclopentadienyl)molybdenum(II), [Mo(C6H5S)(C5H9N)(2)-(C5H5)(CO)]

      McDermott, Lindsay C.; Muir, K.W.; Petillon, F.Y.; PoderGuillou, S.; Schollhammer, P. (Wiley, 1996-01-15)
    • Cleavage of mer tyrosine kinase (MerTK) from the cell surface contributes to the regulation of retinal phagocytosis

      Law, Ah-Lai; Parinot, Celia; Chatagnon, Jonathan; Gravez, Basile; Sahel, Jose-Alain; Bhattacharya, Shomi S.; Nandrot, Emeline F.; ; Sorbonne Universite; University College London; et al. (American Society for Biochemistry and Molecular Biology Inc., 2014-12-23)
      Background: The MerTK receptor is necessary for retinal phagocytosis and its daily rhythm. Results: MerTK is cleaved from the apical cell surface in vitro and in vivo, reducing the phagocytic capacity of RPE cells. Conclusion: MerTK cleavage might help control the duration of the daily phagocytic peak. Significance: Our data show that extracellular cleavage of MerTK partly regulates retinal phagocytosis.
    • The climatic challenge: which plants will people use in the next century?

      Borrell, J.S.; Dodsworth, Steven; Forest, Felix; Pérez-Escobar, Oscar Alejandro; Lee, M.A.; Mattana, E.; Stevenson, P.C.; Howes, M.-J.R.; Pritchard, Hugh W.; Ballesteros, D.; et al. (Elsevier, 2019-08-30)
      More than 31,000 useful plant species have been documented to fulfil needs and services for humans or the animals and environment we depend on. Despite this diversity, humans currently satisfy most requirements with surprisingly few plant species; for example, just three crops – rice, wheat and maize – comprise more than 50% of plant derived calories. Here, we synthesize the projected impact of global climatic change on useful plants across the spectrum of plant domestication. We illustrate the demographic, spatial, ecophysiological, chemical, functional, evolutionary and cultural traits that are likely to characterise useful plants and their resilience in the next century. Using this framework, we consider a range of possible pathways for future human use of plants. These are centred on two trade-offs: i) diversification versus specialization in the range of species we utilize, and ii) substitutionof the species towards those better suited to future climate versus facilitating adaptation in our existing suite of dominant useful plants. In the coming century, major challenges to agriculture and biodiversity will be dominated by increased climatic variation, shifting species ranges, disruption to biotic interactions, nutrient limitation and emerging pests and pathogens. These challenges must be mitigated, whilst enhancing sustainable production to meet the needs of a growing population and a more resource intensive standard of living. With the continued erosion of biodiversity, our future ability to choose among these pathways and trade-offs is likely to be diminished.
    • Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species

      Osborne, Thomas H.; Heath, Matthew D.; Martin, Andrew C.R.; Pankowski, Jaroslaw A.; Hudson-Edwards, Karen A.; Santini, Joanne M.; University College London; Birkbeck, University of London (Royal Society of Chemistry, 2012-10-31)
      Polaromonas sp. str. GM1 is an aerobic, psychrotolerant, heterotrophic member of the Betaproteobacteria and is the only isolate capable of oxidising arsenite at temperatures below 10 °C. Sequencing of the aio gene cluster in GM1 revealed the presence of the aioB and aioA genes, which encode the arsenite oxidase but the regulatory genes typically found upstream of aioB in other members of the Proteobacteria were absent. The GM1 Aio was purified to homogeneity and was found to be a heterodimer. The enzyme contained Mo and Fe as cofactors and had, using the artificial electron acceptor 2,6-dichlorophenolindophenol, a Km for arsenite of 111.70 ± 0.88 μM and a Vmax of 12.16 ± 0.30 U mg(-1), which is the highest reported specific activity for any known Aio. The temperature-activity profiles of the arsenite oxidases from GM1 and the mesophilic betaproteobacterium Alcaligenes faecalis were compared and showed that the GM1 Aio was more active at low temperatures than that of A. faecalis. A homology model of the GM1 Aio was made using the X-ray crystal structure of the Aio from A. faecalis as the template. Structural changes that account for cold adaptation were identified and it was found that these resulted in increased enzyme flexibility and a reduction in the hydrophobicity of the core.
    • Combination of Sanger and target-enrichment markers supports revised generic delimitation in the problematic ‘Urera clade’ of the nettle family (Urticaceae)

      Wells, Tom; Maurin, Olivier; Dodsworth, Steven; Friis, Ib; Cowan, Robyn S.; Epitawalage, Niroshini; Brewer, Grace E.; Forest, Felix; Baker, William; Monro, Alexandre; et al. (Elsevier, 2020-11-05)
      Urera Gaudich, s.l. is a pantropical genus comprising c. 35 species of trees, shrubs, and vines. It has a long history of taxonomic uncertainty, and is repeatedly recovered as polyphyletic within a poorly resolved complex of genera in the Urticeae tribe of the nettle family (Urticaceae). To provide generic delimitations concordant with evolutionary history, we use increased taxonomic and genomic sampling to investigate phylogenetic relationships among Urera and associated genera. A cost-effective two-tier genome-sampling approach provides good phylogenetic resolution by using (i) a taxon-dense sample of Sanger sequence data from two barcoding regions to recover clades of putative generic rank, and (ii) a genome-dense sample of target-enrichment data for a subset of representative species from each well-supported clade to resolve relationships among them. The results confirm the polyphyly of Urera s.l. with respect to the morphologically distinct genera Obetia, Poikilospermum and Touchardia. Afrotropic members of Urera s.l. are recovered in a clade sister to the xerophytic African shrubs Obetia; and Hawaiian ones with Touchardia, also from Hawaii. Combined with distinctive morphological differences between Neotropical and African members of Urera s.l., these results lead us to resurrect the previously synonymised name Scepocarpus Wedd. for the latter. The new species epiphet Touchardia oahuensis T.Wells &amp; A.K. Monro is offered as a replacement name for Touchardia glabra non H.St.John, and subgenera are created within Urera s.s. to account for the two morphologically distinct Neotropical clades. This new classification minimises taxonomic and nomenclatural disruption, while more accurately reflecting evolutionary relationships within the group.
    • Comparison of two reef sites on the north coast of Jamaica over a 15-year period

      Crabbe, M. James C.; University of Oxford; University of Bedfordshire (Scientific Research Publishing, 2016-03-12)
      This paper compares two reef sites near Discovery Bay, Jamaica, Dairy Bull and Dancing Lady, from 2000 to 2015. At Dairy Bull reef, with low macroalgal cover (8% in 2002 falling to 1% in 2015) and significant number of Diadema antillarum urchins (c. 5 m−2), live coral cover increased from 13% ± 5% in 2006 after the bleaching event in 2005, to 31% ± 7% in 2008, while live Acropora cervicornis increased from 2% ± 2% in 2006 to 28% ± 5% in 2015. Coral cover levels were at least maintained until 2015, owing mostly to a slight increase in A. cervicornis. Dancing Lady reef however was dominated by macroalgae throughout this period (cover of c. 76% ± 7%), with no D. antillarum and showed little decrease in the already low (6% ± 1%) coral cover in 2005. Growth rates for Siderastrea siderea were similar for both sites (7 mm∙yr−1), while growth rates of A. cervicornis and A. palmata were 120.0 ± 30 mm∙yr−1 and 71.0 ± 29 mm∙yr−1 respectively at Dairy Bull in 2015. At Dancing Lady reef, A. cervicornis colonies which were present from 2003 to 2005 had disappeared in 2006, possibly as a result of the mass bleaching event. It appears that A. cervicornis was the most impacted species during the 2005 bleaching event, but was also the species that recovered fastest after its decline at Dairy Bull.
    • Comparison study of oral iron preparations using a human intestinal model

      Zariwala, Mohammed Gulrez; Somavarapu, Satyanarayana; Farnaud, Sébastien; Renshaw, Derek; University of Westminster; University College London; University of Bedfordshire (Österreichischer Apothekerverlag, 2013-06-21)
      Iron deficiency and related iron deficiency anaemia (IDA) are the most prevalent nutritional disorders worldwide. The standard treatment involves supplementation with solid or liquid iron supplement preparations, usually based on a ferrous salt such as ferrous sulphate, ferrous fumarate, or ferrous gluconate. In the present study, we compared iron uptake and absorption from various solid and liquid iron supplement preparations currently available in the United Kingdom using the well-characterised human epithelial adenocarcinoma cell line Caco-2. Intracellular ferritin protein formation by the Caco-2 cell was considered an indicator of cellular iron uptake and absorption. We investigated the effects of formulation ingredients at a defined pH on iron uptake and absorption, and designed a novel two-stage dissolution-absorption protocol that mimicked physiological conditions. Our experiments revealed wide variations in the rate of dissolution between the various solid iron preparations. Conventional-release ferrous iron tablets dissolved rapidly (48 ± 4 mins to 64 ± 4 mins), whereas modified-released tablets and capsules took significantly longer to undergo complete dissolution (274 ± 8 to 256 ± 8 mins). Among the solid iron preparations, ferrous sulphate conventional-release tablets demonstrated the highest iron absorption, whereas modified-release ferrous preparations demonstrated uniformly low iron absorption, as compared to the control (P < 0.05). Taken together, our results demonstrate that there are wide-ranging variations in dissolution times and iron uptake from oral iron preparations, with the physical characteristics of the preparation as well as the form of iron playing a key role.