13 research outputs found
A time-course analysis of four full-scale anaerobic digesters in relation to the dynamics of change of their microbial communities
No full textThis study describes the microbial community richness, -dynamics, and -organization of four full-scale anaerobic digesters during a time-course study of 45 days. The microbial community was analyzed using a Bacteria- and Archaea-targeting 16S rRNA gene-based Terminal-Restriction Fragment Length Polymorphism approach. Clustering analysis separated meso- and thermophilic reactors for both archaeal and bacterial communities. Regardless of the operating temperature, each installation possessed a distinct community profile. For both microbial domains, about 8 dominant terminal-restriction fragments could be observed, with a minimum of 4 and a maximum of 14. The bacterial community organization (a coefficient which describes the specific degree of evenness) showed a factor 2 more variation in the mesophilic reactors, compared with the thermophilic ones. The archaeal community structure of the mesophilic UASB reactor was found to be more stable. The community composition was highly dynamic for Bacteria and Archaea, with a rate of change between 20-50% per 15 days. This study illustrated that microbial communities in full-scale anaerobic digesters are unique to the installation and that community properties are dynamic. Converging complex microbial processes such as anaerobic digestion which rely on a multitude of microbial teams apparently can be highly dynamic
Biochemical composition and quality assessment of native macroalgae collected along the Flemish coast: Public Output report of the EnAlgae project, Oostende, December 2015
No full textLithium transport in crown ether polymers
No full textA series of 12-, 13-, and 14-membered crown ether rings bearing polymerisable side-chains has been synthesised. The crown ethers were attached to a methacrylate or acrylate polymerisable group either via a short link (Ring-CH(_2)-O-Polymer) or via a spacer group. Both hydrocarbon and ethylene oxide spacer groups were used, giving structures of the form (Ring-CH(_2)-O-(CH(_2))(_6)-O-Polymer) and (Ring-CH(_2)-O-((CH(_2)CH(_2))(_2)O)-Polymer). The ethylene oxide chain can potentially bind to a Li(^+) dopant ion. The relative Li(+) binding affinity of 12-, 13-, and 14-membered mono- and disubstituted crown ethers has been assessed by variable temperature (^13)c and (^7)Li NMR. The crown ether bearing monomers were polymerised using standard free-radical polymerisation methods to yield amorphous materials whose glass transition temperature (T(_g)) was controlled principally by the nature of the spacer group. On doping with lithium triflate (LiCF(_3)SO(_3)), the polymers exhibit high ionic conductivity. The conductivity was primarily dependent on polymer T(_g), but was also found to be higher for 12-crown-4 based systems than for 13-crown-4 and 14-crown-4 based analogues. This behaviour was consistent with the results of the NMR studies, which showed that Li(^+) exchange occurs more readily between 12-crown-4 rings than 13- or 14-crown-4 rings. The NMR studies also showed that 12-crown-4 systems have a higher tendency to form 2:1 (ring : Li(^+)) complexes. Within a polymer matrix, the presence of 2:1 complexes allows Li(^+) migration via an association-disassociation mechanism, avoiding the high energy intermediate state of a free or weakly bound Li(^+) ion. The greater encapsulation provided by 2:1 complexation may also aid in ion pair separation
Nucleophilic substitution and cyclisation reactions of some polyfluoro-heteroaromatic and polyfluoroaromatic compounds
No full textThis thesis describes the reactions of some highly fluorinated aromatic and heteroaromatic compounds, in particular derivatives of naphthalene, quinoline and isoquinoline. Chapter 1 provides a general introduction to the preparation, reactions and applications of fluorine containing organic materials. Chapter 2 describes the reactions of some quinoline- and isoquinoline- thiolates with dimethyl acetylenedicarboxylate in an attempt to form six membered heterocycles. Chapter 3 describes nucleophilic substitution reactions of heptafluoro- quinoline and -isoquinoline with sulphur and oxygen nucleophiles. The sulphur nucleophiles are found to attack the 6- site in the isoquinoline and the 4- site in the quinoline. The oxygen nucleophiles attack the 1- site in the isoquinoline and 2- and 4- sites in the quinoline. Chapter 4 describes competition experiments of heptafluoro-quinoline and -isoquinoline with nucleophiles. Relative rates of attack at the 1- position and 6- position in the isoquinoline are determined for a variety of nucleophiles. The relative rates of two nucleophiles are determined for 4- attack in the quinoline. The relative reactivities of the two heterocycles are determined for two different nucleophiles. Chapter 5 describes the pyrolysis of heptafluoro-2-naphtiiyl propynoate which yield two difluoro-butenone derivatives. These decarbonylate under further pyrolysis to yield a 1,1-difluorocyclopropene. All the products were identified by X-ray crystallography. Chapter 6 gives experimental details for Chapter 2 to Chapter 5
<em>In vitro</em> experiment on spawning induction of <em>L. conchilega </em>and substrate preference during settlement of the larva
No full textGlycation modulates glutamatergic signaling and exacerbates Parkinson’s disease-like phenotypes
No full textFunding Information: This study was supported by Fundação para a Ciência e Tecnologia (FCT) PTDC/NEU-OSD/5644/2014, by iNOVA4Health UIDB/04462/2020 and UIDP/04462/2020, a program financially supported by FCT/Ministério da Ciência, Tecnologia e Ensino Superior, through national funds; and by Sociedade Portuguesa de Diabetologia. The authors were supported by: A.C. (FCT, PD/BD/136863/2018; ProRegeM – PhD programme, mechanisms of disease and regenerative medicine); B.F.G. (PTDC/NEU-OSD/5644/2014); L.S. (SFRH/BD/143286/2019). T.F.O. is supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - EXC 2067/1- 390729940, and by SFB1286 (B8). Funding Information: We would like to thank the vivarium and behavioral facilities at Instituto de Medicina Molecular?Jo?o Lobo Antunes for all the support. We also thank Prof. Rosalina Fonseca, Prof. S?lvia V. Conde, Dr Rita Machado de Oliveira, Dr Nat?lia Madeira, Dr Liliana Lopes, Dr Tatiana Burrinha, and Dr Catarina Perdig?o for fruitful discussions. We thank Dr Manuela Correia for all the laboratory support. We are deeply thankful to Prof. Jos? Ramalho for kindly allowing the use of equipment for protein analysis. This study was supported by Funda??o para a Ci?ncia e Tecnologia (FCT) PTDC/NEU-OSD/5644/2014, by iNOVA4Health UIDB/04462/2020 and UIDP/04462/2020, a program financially supported by FCT/Minist?rio da Ci?ncia, Tecnologia e Ensino Superior, through national funds; and by Sociedade Portuguesa de Diabetologia. The authors were supported by: A.C. (FCT, PD/BD/136863/2018; ProRegeM ? PhD programme, mechanisms of disease and regenerative medicine); B.F.G. (PTDC/NEU-OSD/5644/2014); L.S. (SFRH/BD/143286/2019). T.F.O. is supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany?s Excellence Strategy - EXC 2067/1- 390729940, and by SFB1286 (B8). Publisher Copyright: © 2022, The Author(s).Alpha-synuclein (aSyn) is a central player in the pathogenesis of synucleinopathies due to its accumulation in typical protein aggregates in the brain. However, it is still unclear how it contributes to neurodegeneration. Type-2 diabetes mellitus is a risk factor for Parkinson’s disease (PD). Interestingly, a common molecular alteration among these disorders is the age-associated increase in protein glycation. We hypothesized that glycation-induced neuronal dysfunction is a contributing factor in synucleinopathies. Here, we dissected the impact of methylglyoxal (MGO, a glycating agent) in mice overexpressing aSyn in the brain. We found that MGO-glycation potentiates motor, cognitive, olfactory, and colonic dysfunction in aSyn transgenic (Thy1-aSyn) mice that received a single dose of MGO via intracerebroventricular injection. aSyn accumulates in the midbrain, striatum, and prefrontal cortex, and protein glycation is increased in the cerebellum and midbrain. SWATH mass spectrometry analysis, used to quantify changes in the brain proteome, revealed that MGO mainly increase glutamatergic-associated proteins in the midbrain (NMDA, AMPA, glutaminase, VGLUT and EAAT1), but not in the prefrontal cortex, where it mainly affects the electron transport chain. The glycated proteins in the midbrain of MGO-injected Thy1-aSyn mice strongly correlate with PD and dopaminergic pathways. Overall, we demonstrated that MGO-induced glycation accelerates PD-like sensorimotor and cognitive alterations and suggest that the increase of glutamatergic signaling may underly these events. Our study sheds new light into the enhanced vulnerability of the midbrain in PD-related synaptic dysfunction and suggests that glycation suppressors and anti-glutamatergic drugs may hold promise as disease-modifying therapies for synucleinopathies.publishersversionpublishe
Organic thionitroso compounds
No full textA series of novel N-substituted phthalimide-2-sulplienamides was prepared. The N-aryl analogues were shown to be efficient precursors to thionitrosoarenes. Extension of the methodology to heteroaroraatic and acyl derivatives was unsuccessful, with the exception of 3-thionitroso- pyridine, the first known thionitrosoheteroarene. Thionitrosoarenes are shown to be versatile dienophiles and enophiles. Reactions with various substituted dienes proceeded with high stereoselectivity and some regioselectivity to afford 3,6-dihydro- 1,2-thiazines. Cycloadditions of thionitrosoarenes generated independently from imidosulphurous chloride precursors showed similar selectivities. The mechanism of cycloaddition is discussed in the light of molecular orbital calculations
Synthetic ionophores for cations
No full textA series of 14-crown-4 derivatives bearing amide substituents have been prepared in order to develop ionophores selective for lithium. Complexation with lithium ions was monitored using (^13)C and IR spectroscopy and liquid membrane electrodes prepared and evaluated using a fixed interference method. The highest selectivities with respect to sodium ions were obtained for di-n-butylamide-oNPOE and a di-n-benzylamide-oNPOE derivatives; log(^POT)(_ Li,Na) = -2.92 and -2.93 respectively. A series of amide and amide-ester N-functionalised coronands based upon [12]-N202 , [15]-N203 and [18]-N204 parent macrocycles has been prepared. Complexation of certain alkali and alkaline-earth cations was monitored by (^13)C NMR and IR specteoscopy, enthalpies of complexation measured in methanolic solution using micro-calorimetry and stability constants measured in aqueous media by potentiometric methods. Strong complexation of Ca2+ in aqueous media was observed with good selectivity over Na+ and K+. Lower free energies of binding for Ha cations were displayed by the tertiary amide derivative (of [12]N(_2)O(_2)), than by its secondary analogue, despite displaying higher enthalpies of complexation. Thus the lower free energies result from significantly lower entropies of complexation. Two sets of oxa-amide and oxa-ester tripodal ligands have been prepared and solvent membranes fabricated. The effects of the nature of the plasticiser, bis (butylpentyl)adipate (BBPA) verses o -nitrophenyl octyl ether (oNPOE), the ligand structure and the ionic strength of the analyte solution on the electrode response to la and Ila cations were studied. The performance of the oxa-amides was superior to that of the oxa-esters particularly at higher ionic strengths, however super-Nernstian responses were observed with the more charge-dense ions in the presence of chloride and/or with the less polar plasticiser BBPA. Measurements of intracellular sodium concentration could be effected with a sensor based upon bis (N,N',N"-tributyl)-4,4',4"-propylidintris(3-oxabutanamide) and oNPOE for which -log KPOT = 2.64 and -log KPOT =3.0, whilst bis (N,N',N"-tributyl)Na,K Na,Mg-2,2',2"-phenylmethylidintris(3-oxabutamide) and oNPOE functioned as a calcium sensor, displaying excellent selectivity over Mg. -log KPOT= 4.3.Ca,MgAdditionally a triamide based upon a cyclohexane triol skeleton was prepared, a membrane fabricated and its performance assessed as a sodium sensor
Yttrium macrocycles and their use in the treatment of cancer
No full textSix macrocyclic ligands have been synthesized for binding yttrium(III). Of the six, 1,4,7,10-tetraazacyclododecane-1,4,7,10- tetraacetic acid (DOTA) forms the most stable yttrium(III) complex in aqueous solution, log K(ML) = 24.9 and half life ~ 2 weeks at pH 1.0. In addition to an acid-dependent dissociative mechanism, release of Y(^3+) from Y(DOTA) may, it is tentatively suggested, be promoted by metal ions. DOTA also demonstrates rapid uptake of Y(^3+) (98% labelling efficiency at 310 K with [DOTA] = 10(^-5) M and [Y(^3+)1 ~ 10(^-9) M, pH 5.5 [0.1 M ammonium acetate]). Accordingly, an aminobutyl C-functionalised derivative of DOTA has been made and coupled to a monoclonal antibody. Once labelled with (^90)Y(^3+) a long range β- emitter, the conjugate can be used to selectively deliver a sterilising dose of radiation to a tumour. Preliminary experiments have indicated that the radiolabelled MoAb conjugate remains relatively inert in vivo. Tumour regression studies are in progress
