Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 364
Filter
1.
Rheumatol Adv Pract ; 8(3): rkae090, 2024.
Article in English | MEDLINE | ID: mdl-39165399

ABSTRACT

Objectives: Rituximab is used for remission induction and the prevention of relapse in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). This study evaluated the incidence of safety events and compared time to first serious adverse event (SAE) between a rituximab cohort and a cohort treated with non-rituximab therapies in a real-life setting. Methods: Rituximab surveillance study in vasculitis was a retrospective observational study of patients with AAV who received rituximab (MabThera) or other treatments between 2003 and 2017 at a specialist vasculitis clinic. The primary endpoint was time to first SAE. Results: 392 patients were enrolled: 247 in the rituximab and 145 in the control cohorts with a total follow up of 2217 person-years (mean study duration 5.7 years). Mean age was 61 years, 77% had granulomatosis with polyangiitis (GPA). There were differences in baseline characteristics (disease duration and prior immunosuppressive use) between groups. 134/247 patients (54%) in the rituximab and 58/145 (40%) of controls experienced at least one SAE. Time to first SAE was shorter in the rituximab group (hazard ratio (HR) 1.55, 95% CI 1.07-2.26, P = 0.022). Predictors of first SAE were higher vasculitis damage index and the presence of chronic pulmonary or kidney disease. The risk of serious infection was higher in the rituximab group (relative risk (RR) 2.12, 95% CI 1.31-3.43). Conclusion: Over 40% of patients with AAV experienced at least one SAE. Although shorter time to first SAE and higher risk of infection were observed in the rituximab group, baseline imbalances necessitate a careful interpretation of these results.

2.
ACS Appl Opt Mater ; 2(8): 1653-1666, 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39206344

ABSTRACT

The present work reports on the ultrafast nonlinear optical (NLO) properties of a series of D-π-Α and D-A push-pull carbazole-based dyes and establishes a correlation between these properties and their efficiency for potential photonic and optoelectronic applications such as multiphoton lithography (MPL). The ultrafast NLO properties of the studied dyes are determined by two distinct experimental techniques, Z-scan and pump-probe optical Kerr effect (OKE), employing 246 fs laser pulses at 515 nm. The results indicate that chemical functionalization of the carbazole moiety with various strong electron-donating and/or electron-withdrawing groups, such as benzene, styrene, 4-bromostyrene, nitrobenzene, trimethyl isocyanurate, methyl, and indane-1,3-dione, can result in a controlled and significant enhancement of the NLO absorptive and refractive responses. In the context of potential applications, the efficiency of carbazole-based organic materials as photoinitiators (PIs) for MPL applications is demonstrated. The fabricated woodpile microstructure using chemically functionalized carbazole as a PI demonstrates improvements in both feature size and MPL efficiency compared to that using unfunctionalized carbazole as a PI. This is attributed to the efficient charge transfer resulting from chemical functionalization, which leads to a substantial increase (approximately 1 order of magnitude) in the values of the imaginary part of the second-order hyperpolarizability (Imγ) and the two-photon absorption cross section (σ). The achieved feature size of 280 nm is comparable to that obtained with other widely used PIs in MPL applications. Additionally, owing to the strong NLO properties of the studied functionalized carbazole, they could also be promising candidates for further applications in photonics and optoelectronics.

3.
Bioorg Med Chem Lett ; 110: 129889, 2024 Sep 15.
Article in English | MEDLINE | ID: mdl-39004318

ABSTRACT

Studies have shown that disrupting the formation of the ligand-RET-GFRα complex could be an effective way of treating pain and itch. Compared to traditional high-throughput screens, DNA encoded libraries (DELs) have distinguished themselves as a powerful technology for hit identification in recent years. The present work demonstrates the use of DEL technology identifying compound 16 as the first GFRa2/GFRa3 small molecule inhibitor (0.1/0.2 µM respectively) selective over RET. This molecule represents an opportunity to advance the development of small-molecule inhibitors targeting the GFRα-RET interface for the treatment of pain and itch.


Subject(s)
DNA , Glial Cell Line-Derived Neurotrophic Factor Receptors , Small Molecule Libraries , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Small Molecule Libraries/chemical synthesis , Humans , DNA/chemistry , DNA/metabolism , Glial Cell Line-Derived Neurotrophic Factor Receptors/metabolism , Glial Cell Line-Derived Neurotrophic Factor Receptors/antagonists & inhibitors , Drug Discovery , Structure-Activity Relationship , Molecular Structure , Dose-Response Relationship, Drug
4.
Sci Data ; 11(1): 708, 2024 Jun 28.
Article in English | MEDLINE | ID: mdl-38942791

ABSTRACT

The order Orthoptera includes insects such as grasshoppers, katydids, and crickets, among which there are important species for ecosystem stability and pollination, as well as research organisms in different fields such as neurobiology, ecology, and evolution. Crickets, with more than 2,400 described species, are emerging as novel model research organisms, for their diversity, worldwide distribution, regeneration capacity, and their characteristic acoustic communication. Here we report the assembly and annotation of the first New World cricket, that of Gryllus longicercus Weissman & Gray 2019. The genome assembly, generated by combining 44.54 Gb of long reads from PacBio and 120.44 Gb of short Illumina reads, has a length of 1.85 Gb. The genome annotation yielded 19,715 transcripts from 14,789 gene models.


Subject(s)
Genome, Insect , Gryllidae , Molecular Sequence Annotation , Gryllidae/genetics , Animals
5.
ACS Infect Dis ; 10(6): 2002-2017, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38753953

ABSTRACT

Leishmaniasis is a neglected tropical disease; there is currently no vaccine and treatment is reliant upon a handful of drugs suffering from multiple issues including toxicity and resistance. There is a critical need for development of new fit-for-purpose therapeutics, with reduced toxicity and targeting new mechanisms to overcome resistance. One enzyme meriting investigation as a potential drug target in Leishmania is M17 leucyl-aminopeptidase (LAP). Here, we aimed to chemically validate LAP as a drug target in L. major through identification of potent and selective inhibitors. Using RapidFire mass spectrometry, the compounds DDD00057570 and DDD00097924 were identified as selective inhibitors of recombinant Leishmania major LAP activity. Both compounds inhibited in vitro growth of L. major and L. donovani intracellular amastigotes, and overexpression of LmLAP in L. major led to reduced susceptibility to DDD00057570 and DDD00097924, suggesting that these compounds specifically target LmLAP. Thermal proteome profiling revealed that these inhibitors thermally stabilized two M17 LAPs, indicating that these compounds selectively bind to enzymes of this class. Additionally, the selectivity of the inhibitors to act on LmLAP and not against the human ortholog was demonstrated, despite the high sequence similarities LAPs of this family share. Collectively, these data confirm LmLAP as a promising therapeutic target for Leishmania spp. that can be selectively inhibited by drug-like small molecules.


Subject(s)
Antiprotozoal Agents , Leishmania major , Leishmania major/enzymology , Leishmania major/drug effects , Leishmania major/genetics , Antiprotozoal Agents/pharmacology , Antiprotozoal Agents/chemistry , Protozoan Proteins/metabolism , Protozoan Proteins/antagonists & inhibitors , Protozoan Proteins/genetics , Protozoan Proteins/chemistry , Animals , Humans , Leishmania donovani/enzymology , Leishmania donovani/drug effects , Leishmania donovani/genetics
7.
ChemMedChem ; 19(13): e202400025, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38581280

ABSTRACT

Identification and assessment of novel targets is essential to combat drug resistance in the treatment of HIV/AIDS. HIV Capsid (HIV-CA), the protein playing a major role in both the early and late stages of the viral life cycle, has emerged as an important target. We have applied an NMR fragment screening platform and identified molecules that bind to the N-terminal domain (NTD) of HIV-CA at a site close to the interface with the C-terminal domain (CTD). Using X-ray crystallography, we have been able to obtain crystal structures to identify the binding mode of these compounds. This allowed for rapid progression of the initial, weak binding, fragment starting points to compounds 37 and 38, which have 19F-pKi values of 5.3 and 5.4 respectively.


Subject(s)
Anti-HIV Agents , Crystallography, X-Ray , Anti-HIV Agents/chemistry , Anti-HIV Agents/pharmacology , Anti-HIV Agents/chemical synthesis , Binding Sites , Drug Discovery , HIV-1/drug effects , Protein Binding , Capsid Proteins/metabolism , Capsid Proteins/chemistry , Capsid Proteins/antagonists & inhibitors , Humans , Molecular Structure , Models, Molecular , Magnetic Resonance Spectroscopy , Structure-Activity Relationship
8.
PLoS Negl Trop Dis ; 18(2): e0011956, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38359089

ABSTRACT

BACKGROUND: Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and leads to ~10,000 deaths each year. Nifurtimox and benznidazole are the only two drugs available but have significant adverse effects and limited efficacy. New chemotherapeutic agents are urgently required. Here we identified inhibitors of the acidic M17 leucyl-aminopeptidase from T. cruzi (LAPTc) that show promise as novel starting points for Chagas disease drug discovery. METHODOLOGY/PRINCIPAL FINDINGS: A RapidFire-MS screen with a protease-focused compound library identified novel LAPTc inhibitors. Twenty-eight hits were progressed to the dose-response studies, from which 12 molecules inhibited LAPTc with IC50 < 34 µM. Of these, compound 4 was the most potent hit and mode of inhibition studies indicate that compound 4 is a competitive LAPTc inhibitor, with Ki 0.27 µM. Compound 4 is selective with respect to human LAP3, showing a selectivity index of >500. Compound 4 exhibited sub-micromolar activity against intracellular T. cruzi amastigotes, and while the selectivity-window against the host cells was narrow, no toxicity was observed for un-infected HepG2 cells. In silico modelling of the LAPTc-compound 4 interaction is consistent with the competitive mode of inhibition. Molecular dynamics simulations reproduce the experimental binding strength (-8.95 kcal/mol), and indicate a binding mode based mainly on hydrophobic interactions with active site residues without metal cation coordination. CONCLUSIONS/SIGNIFICANCE: Our data indicates that these new LAPTc inhibitors should be considered for further development as antiparasitic agents for the treatment of Chagas disease.


Subject(s)
Chagas Disease , Trypanocidal Agents , Trypanosoma cruzi , Humans , Leucyl Aminopeptidase/chemistry , Leucyl Aminopeptidase/pharmacology , Leucyl Aminopeptidase/therapeutic use , Chagas Disease/drug therapy , Drug Discovery , Antiparasitic Agents/therapeutic use , Trypanocidal Agents/therapeutic use
9.
CNS Neurol Disord Drug Targets ; 23(4): 476-487, 2024.
Article in English | MEDLINE | ID: mdl-36999711

ABSTRACT

Currently, available therapeutics for the treatment of Parkinson's disease (PD) fail to provide sustained and predictable relief from motor symptoms without significant risk of adverse events (AEs). While dopaminergic agents, particularly levodopa, may initially provide strong motor control, this efficacy can vary with disease progression. Patients may suffer from motor fluctuations, including sudden and unpredictable drop-offs in efficacy. Dopamine agonists (DAs) are often prescribed during early-stage PD with the expectation they will delay the development of levodopa-associated complications, but currently available DAs are less effective than levodopa for the treatment of motor symptoms. Furthermore, both levodopa and DAs are associated with a significant risk of AEs, many of which can be linked to strong, repeated stimulation of D2/D3 dopamine receptors. Targeting D1/D5 dopamine receptors has been hypothesized to produce strong motor benefits with a reduced risk of D2/D3-related AEs, but the development of D1-selective agonists has been previously hindered by intolerable cardiovascular AEs and poor pharmacokinetic properties. There is therefore an unmet need in PD treatment for therapeutics that provide sustained and predictable efficacy, with strong relief from motor symptoms and reduced risk of AEs. Partial agonism at D1/D5 has shown promise for providing relief from motor symptoms, potentially without the AEs associated with D2/D3-selective DAs and full D1/D5-selective DAs. Tavapadon is a novel oral partial agonist that is highly selective at D1/D5 receptors and could meet these criteria. This review summarizes currently available evidence of tavapadon's therapeutic potential for the treatment of early through advanced PD.


Subject(s)
Dopamine Agonists , Parkinson Disease , Humans , Dopamine Agonists/therapeutic use , Parkinson Disease/drug therapy , Levodopa/therapeutic use , Dopamine Agents/therapeutic use , Receptors, Dopamine D2 , Receptors, Dopamine D1 , Antiparkinson Agents/therapeutic use
10.
PLoS Negl Trop Dis ; 17(12): e0011799, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38150490

ABSTRACT

There is a need for novel chemical matter for phenotypic and target-based screens to find starting points for drug discovery programmes in neglected infectious diseases and non-hormonal contraceptives that disproportionately affect Low- and Middle-Income Countries (LMICs). In some disease areas multiple screens of corporate and other libraries have been carried out, giving rise to some valuable starting points and leading to preclinical candidates. Whilst in other disease areas, little screening has been carried out. Much screening against pathogens has been conducted phenotypically as there are few robustly validated protein targets. However, many of the active compound series identified share the same molecular targets. To address the need for new chemical material, in this article we describe the design of a new library, designed for screening in drug discovery programmes for neglected infectious diseases. The compounds have been selected from the Enamine REAL (REadily AccessibLe) library, a virtual library which contains approximately 4.5 billion molecules. The molecules theoretically can be synthesized quickly using commercially available intermediates and building blocks. The vast majority of these have not been prepared before, so this is a source of novel compounds. In this paper we describe the design of a diverse library of 30,000 compounds from this collection (graphical abstract). The new library will be made available to laboratories working in neglected infectious diseases, subject to a review process. The project has been supported by the Bill & Melinda Gates Foundation and the Wellcome Trust (Wellcome).


Subject(s)
Communicable Diseases , Global Health , Humans , Small Molecule Libraries/chemistry , Drug Discovery , Communicable Diseases/diagnosis
11.
Front Immunol ; 14: 1241474, 2023.
Article in English | MEDLINE | ID: mdl-37638026

ABSTRACT

B cells are key pathogenic drivers of chronic inflammation in rheumatoid arthritis (RA). There is limited understanding of the relationship between synovial B cell subsets and pathogenic antibody secreting cells (ASCs). This knowledge is crucial for the development of more targeted B-cell depleting therapies. While CD11c+ double-negative 2 (DN2) B cells have been suggested as an ASC precursor in lupus, to date there is no proven link between the two subsets in RA. We have used both single-cell gene expression and BCR sequencing to study synovial B cells from patients with established RA, in addition to flow cytometry of circulating B cells. To better understand the differentiation patterns within the diseased tissue, a combination of RNA-based trajectory inference and clonal lineage analysis of BCR relationships were used. Both forms of analysis indicated that DN2 B cells serve as a major precursors to synovial ASCs. This study advances our understanding of B cells in RA and reveals the origin of pathogenic ASCs in the RA synovium. Given the significant role of DN2 B cells as a progenitor to pathogenic B cells in RA, it is important to conduct additional research to investigate the origins of DN2 B cells in RA and explore their potential as therapeutic targets in place of the less specific pan-B cells depletion therapies currently in use.


Subject(s)
Arthritis, Rheumatoid , B-Lymphocyte Subsets , Humans , Plasma Cells , B-Lymphocytes , Antibody-Producing Cells
12.
Br J Nurs ; 32(15): S12-S18, 2023 Aug 17.
Article in English | MEDLINE | ID: mdl-37596073

ABSTRACT

This article explores the impact of combining tissue viability and lymphoedema techniques on optimising time to healing. AIM: To investigate the healing rates observed in patients who presented to wound and lymphoedema specialist clinics, located in the south eastern region of England, with venous/lymphovenous ulceration of the lower limb during the COVID-19 pandemic in 2020-2022 (30 months in all). METHODOLOGY: A retrospective analysis of patient outcomes. RESULTS: 1041 patients were referred to the service, with a healing rate of 88.5% over 78 days. DISCUSSION: When comparing 2013-2019 healing rates/time to healing vs 2020-2022 there was a decrease of 1.5% in the rate of healing and a mean reduction in time to healing of 40 days. CONCLUSION: Despite the pandemic the service was able to maintain previous levels of outcomes and observed a decrease in the mean time to healing.


Subject(s)
COVID-19 , Lymphedema , Varicose Ulcer , Humans , Pandemics , Retrospective Studies , England/epidemiology , Lower Extremity
13.
Clin Park Relat Disord ; 9: 100212, 2023.
Article in English | MEDLINE | ID: mdl-37497384

ABSTRACT

Dopamine agonists (DAs) have demonstrated efficacy for the treatment of Parkinson's disease (PD) but are limited by adverse effects (AEs). DAs can vary considerably in their receptor subtype selectivity and affinity, chemical composition, receptor occupancy, and intrinsic activity on the receptor. Most currently approved DAs for PD treatment primarily target D2/D3 (D2-like) dopamine receptors. However, selective activation of D1/D5 (D1-like) dopamine receptors may enable robust activation of motor function while avoiding AEs related to D2/D3 receptor agonism. Full D1/D5 receptor-selective agonists have been explored in small, early-phase clinical studies, and although their efficacy for motor symptoms was robust, challenges with pharmacokinetics, bioavailability, cardiovascular AEs, and dyskinesia rates similar to levodopa prevented clinical advancement. Generally, repeated dopaminergic stimulation with full DAs is associated with frontostriatal dysfunction and sensitization that may induce plastic changes in the motor system, and neuroadaptations that produce long-term motor and nonmotor complications, respectively. Recent preclinical and clinical studies suggest that a D1/D5 receptor-selective partial agonist may hold promise for providing sustained, predictable, and robust motor control, while reducing risk for motor complications (e.g., levodopa-induced dyskinesia) and nonmotor AEs (e.g., impulse control disorders and excessive daytime sleepiness). Clinical trials are ongoing to evaluate this hypothesis. The potential emerging availability of novel dopamine receptor agonists with selective dopamine receptor pharmacology suggests that the older terminology "dopamine agonist" may need revision to distinguish older-generation D2/D3-selective agonists from D1/D5-selective agonists with distinct efficacy and tolerability characteristics.

14.
J Pers Med ; 13(7)2023 Jun 21.
Article in English | MEDLINE | ID: mdl-37511639

ABSTRACT

BACKGROUND: It is critical to understand the wide-ranging clinical and non-clinical effects of genome sequencing (GS) for parents in the NICU context. We assessed parents' experiences with GS as a first-line diagnostic tool for infants with suspected genetic conditions in the NICU. METHODS: Parents of newborns (N = 62) suspected of having a genetic condition were recruited across five hospitals in the southeast United States as part of the SouthSeq study. Semi-structured interviews (N = 78) were conducted after parents received their child's sequencing result (positive, negative, or variants of unknown significance). Thematic analysis was performed on all interviews. RESULTS: Key themes included that (1) GS in infancy is important for reproductive decision making, preparing for the child's future care, ending the diagnostic odyssey, and sharing results with care providers; (2) the timing of disclosure was acceptable for most parents, although many reported the NICU environment was overwhelming; and (3) parents deny that receiving GS results during infancy exacerbated parent-infant bonding, and reported variable impact on their feelings of guilt. CONCLUSION: Parents reported that GS during the neonatal period was useful because it provided a "backbone" for their child's care. Parents did not consistently endorse negative impacts like interference with parent-infant bonding.

16.
Biol Psychiatry Glob Open Sci ; 3(3): 340-350, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37519466

ABSTRACT

The phenotype of schizophrenia, regardless of etiology, represents the most studied psychotic disorder with respect to neurobiology and distinct phases of illness. The early phase of illness represents a unique opportunity to provide effective and individualized interventions that can alter illness trajectories. Developmental age and illness stage, including temporal variation in neurobiology, can be targeted to develop phase-specific clinical assessment, biomarkers, and interventions. We review an earlier model whereby an initial glutamate signaling deficit progresses through different phases of allostatic adaptation, moving from potentially reversible functional abnormalities associated with early psychosis and working memory dysfunction, and ending with difficult-to-reverse structural changes after chronic illness. We integrate this model with evidence of dopaminergic abnormalities, including cortical D1 dysfunction, which develop during adolescence. We discuss how this model and a focus on a potential critical window of intervention in the early stages of schizophrenia impact the approach to research design and clinical care. This impact includes stage-specific considerations for symptom assessment as well as genetic, cognitive, and neurophysiological biomarkers. We examine how phase-specific biomarkers of illness phase and brain development can be incorporated into current strategies for large-scale research and clinical programs implementing coordinated specialty care. We highlight working memory and D1 dysfunction as early treatment targets that can substantially affect functional outcome.

17.
Biomolecules ; 13(5)2023 05 12.
Article in English | MEDLINE | ID: mdl-37238699

ABSTRACT

Current pharmacotherapy has limited efficacy and/or intolerable side effects in late-stage Parkinson's disease (LsPD) patients whose daily life depends primarily on caregivers and palliative care. Clinical metrics inadequately gauge efficacy in LsPD patients. We explored if a D1/5 dopamine agonist would have efficacy in LsPD using a double-blind placebo-controlled crossover phase Ia/b study comparing the D1/5 agonist PF-06412562 to levodopa/carbidopa in six LsPD patients. Caregiver assessment was the primary efficacy measure because caregivers were with patients throughout the study, and standard clinical metrics inadequately gauge efficacy in LsPD. Assessments included standard quantitative scales of motor function (MDS-UPDRS-III), alertness (Glasgow Coma and Stanford Sleepiness Scales), and cognition (Severe Impairment and Frontal Assessment Batteries) at baseline (Day 1) and thrice daily during drug testing (Days 2-3). Clinicians and caregivers completed the clinical impression of change questionnaires, and caregivers participated in a qualitative exit interview. Blinded triangulation of quantitative and qualitative data was used to integrate findings. Neither traditional scales nor clinician impression of change detected consistent differences between treatments in the five participants who completed the study. Conversely, the overall caregiver data strongly favored PF-06412562 over levodopa in four of five patients. The most meaningful improvements converged on motor, alertness, and functional engagement. These data suggest for the first time that there can be useful pharmacological intervention in LsPD patients using D1/5 agonists and also that caregiver perspectives with mixed method analyses may overcome limitations using methods common in early-stage patients. The results encourage future clinical studies and understanding of the most efficacious signaling properties of a D1 agonist for this population.


Subject(s)
Parkinson Disease , Humans , Parkinson Disease/drug therapy , Levodopa/therapeutic use , Levodopa/adverse effects , Dopamine Agonists/therapeutic use , Antiparkinson Agents/therapeutic use , Dopamine
18.
ACS Omega ; 8(14): 12787-12804, 2023 Apr 11.
Article in English | MEDLINE | ID: mdl-37065080

ABSTRACT

There is an urgent need for the development of new therapeutics with novel modes of action to target Gram-negative bacterial infections, due to resistance to current drugs. Previously, FabA, an enzyme in the bacterial type II fatty acid biosynthesis pathway, was identified as a potential drug target in Pseudomonas aeruginosa, a Gram-negative bacteria of significant clinical concern. A chemical starting point was also identified. There is a cysteine, Cys15, in the active site of FabA, adjacent to where this compound binds. This paper describes the preparation of analogues containing an electrophilic warhead with the aim of covalent inhibition of the target. A wide variety of analogues were successfully prepared. Unfortunately, these analogues did not increase inhibition, which may be due to a loop within the enzyme partially occluding access to the cysteine.

19.
Food Res Int ; 165: 112472, 2023 03.
Article in English | MEDLINE | ID: mdl-36869485

ABSTRACT

Chloroplasts are abundant organelles in a diverse range of plant materials; they are predominantly composed of multicomponent thylakoid membranes which are lipid and protein rich. Intact or unravelled thylakoid membranes should, in principle, have interfacial activity, but little has been published on their activity in oil-in-water systems, and nothing on their performance on an oil continuous system. In this work different physical methods were used to produce a range of chloroplast/thylakoid suspensions with varying degrees of membrane integrity. Transmission electron microscopy revealed that pressure homogenisation led to the greatest extent of membrane and organelle disruption compared to less energy intensive preparation methods The ability of the derived materials to modulate the flow behaviour of a chocolate model system (65% (w/w) sugar/ sunflower oil (natural amphiphiles removed) suspension) was investigated by acquiring rheological parameters. All chloroplast/thylakoid preparations reduced yield stress, apparent viscosity, tangent flow point and cross over point in a concentration-dependent fashion, although not as significantly as polyglycerol polyricinoleate applied at a commercially relevant concentration in the same chocolate model system. Confocal laser scanning microscopy confirmed presence of the alternative flow enhancer material at the sugar surfaces. This research reveals that low-energy processing methods that do not extensively disrupt thylakoid membranes are applicable to generating materials with marked capacity to affect the flow behaviour of a chocolate model system. In conclusion, chloroplast/thylakoid materials hold strong potential as natural alternatives to synthetic rheology modifiers for lipid-based systems such as PGPR.


Subject(s)
Cacao , Thylakoids , Chloroplasts , Ricinoleic Acids , Sugars
20.
Chem Phys Lipids ; 252: 105291, 2023 05.
Article in English | MEDLINE | ID: mdl-36918051

ABSTRACT

Galactolipids are the main lipids from plant photosynthetic membranes and they can be digested by pancreatic lipase related protein 2 (PLRP2), an enzyme found in the pancreatic secretion in many animal species. Here, we used transmission Fourier-transform infrared spectroscopy (FTIR) to monitor continuously the hydrolysis of galactolipids by PLRP2, in situ and in real time. The method was first developed with a model substrate, a synthetic monogalactosyl diacylglycerol with 8-carbon acyl chains (C8-MGDG), in the form of mixed micelles with a bile salt, sodium taurodeoxycholate (NaTDC). The concentrations of the residual substrate and reaction products (monogalactosylmonoglyceride, MGMG; monogalactosylglycerol, MGG; octanoic acid) were estimated from the carbonyl and carboxylate vibration bands after calibration with reference standards. The results were confirmed by thin layer chromatography analysis (TLC) and specific staining of galactosylated compounds with thymol and sulfuric acid. The method was then applied to the lipolysis of more complex substrates, a natural extract of MGDG with long acyl chains, micellized with NaTDC, and intact chloroplasts isolated from spinach leaves. After a calibration performed with α-linolenic acid, the main fatty acid (FA) found in plant galactolipids, FTIR allowed quantitative measurement of chloroplast lipolysis by PLRP2. A full release of FA from membrane galactolipids was observed, that was not dependent on the presence of bile salts. Nevertheless, the evolution of amide vibration band in FTIR spectra suggested the interaction of membrane proteins with NaTDC and lipolysis products.


Subject(s)
Galactolipids , Micelles , Animals , Galactolipids/chemistry , Galactolipids/metabolism , Spinacia oleracea/chemistry , Spinacia oleracea/metabolism , Fatty Acids/metabolism , Spectrophotometry, Infrared , Chloroplasts/metabolism , Digestion
SELECTION OF CITATIONS
SEARCH DETAIL