Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 23
Filter
Add more filters










Publication year range
1.
BMJ Open ; 13(10): e071852, 2023 10 06.
Article in English | MEDLINE | ID: mdl-37802621

ABSTRACT

OBJECTIVE: To evaluate the impact of mobile vaccination units on COVID-19 vaccine uptake of the first dose, the percentage of vaccinated people among the total eligible population. We further investigate whether such an effect differed by deprivation, ethnicity and age. DESIGN: Synthetic control analysis. SETTING: The population registered with general practices (GPs) in nine local authority areas in Cheshire and Merseyside in Northwest England, UK. INTERVENTION: Mobile vaccination units that visited 37 sites on 54 occasions between 12 April 2021 and 28 June 2021. We defined intervention neighbourhoods as having their population weighted centroid located within 1 km of mobile vaccination sites (338 006 individuals). A weighted combination of neighbourhoods that had not received the intervention (1 495 582 individuals) was used to construct a synthetic control group. OUTCOME: The weekly number of first-dose vaccines received among people aged 18 years and over as a proportion of the population. RESULTS: The introduction of a mobile vaccination unit into a neighbourhood increased the number of first vaccinations conducted in the neighbourhood by 25% (95% CI 21% to 28%) within 3 weeks after the first visit to a neighbourhood, compared with the synthetic control group. Interaction analyses showed smaller or no effect among older age groups, Asian and black ethnic groups, and the most socioeconomically deprived populations. CONCLUSIONS: Mobile vaccination units are effective interventions for increasing vaccination uptake, at least in the short term. While mobile units can be geographically targeted to reduce inequalities, we found evidence that they may increase inequalities in vaccine uptake within targeted areas, as the intervention was less effective among groups that tended to have lower vaccination uptake. Mobile vaccination units should be used in combination with activities to maximise outreach with black and Asian communities and socioeconomically disadvantaged groups.


Subject(s)
COVID-19 , Vaccines , Humans , Adolescent , Adult , Aged , COVID-19 Vaccines , COVID-19/epidemiology , COVID-19/prevention & control , Vaccination , England
2.
Sci Med Footb ; 6(5): 547-548, 2022 12 01.
Article in English | MEDLINE | ID: mdl-36513595

Subject(s)
Soccer , Female , Humans
3.
J Agric Food Chem ; 69(44): 13164-13172, 2021 Nov 10.
Article in English | MEDLINE | ID: mdl-34709813

ABSTRACT

Copper-sulfhydryl complexes in wine can be disrupted by addition of brine to release free hydrogen sulfide (H2S), and the resulting "brine-releasable H2S" is reported to correlate with formation of H2S during bottle storage. However, both the mechanism of the brine-release assay and factors affecting the stability of copper sulfhydryls under brine-release conditions are not well understood. By varying brine composition and concentration, it is shown that release of copper-complexed H2S requires the presence of a halide (Cl- and Br-) and is not due to a general "salting-out" effect. Release of copper-complexed H2S by the brine dilution assay is highly temperature-dependent. When H2S and Cu(II) are added to a model wine, brine-releasable H2S decreases markedly (∼10-fold) after a 20 min incubation period prior to performing the brine-release assay. In commercial wines, the fraction of added H2S recovered through the brine-release assay was correlated with the initial glutathione (GSH) concentration (r2 = 0.58) but not with initial Cu. Negligible additional release of H2S from organopolysulfanes was observed following addition of a disulfide-reducing agent (tris(2-carboxyethyl)phosphine). As previous studies have reported a correlation between H2S formed under brine-release conditions and normal storage, these results suggest that the susceptibility of a wine to form latent copper-sulfhydryl precursors of H2S following copper addition is dependent on the concentration of sulfhydryls like GSH.


Subject(s)
Hydrogen Sulfide , Wine , Copper , Glutathione , Salts , Wine/analysis
4.
Am J Hum Genet ; 107(6): 1129-1148, 2020 12 03.
Article in English | MEDLINE | ID: mdl-33186545

ABSTRACT

The endosomal sorting complexes required for transport (ESCRTs) are essential for multiple membrane modeling and membrane-independent cellular processes. Here we describe six unrelated individuals with de novo missense variants affecting the ATPase domain of VPS4A, a critical enzyme regulating ESCRT function. Probands had structural brain abnormalities, severe neurodevelopmental delay, cataracts, growth impairment, and anemia. In cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A. Proband-derived fibroblasts had enlarged endosomal structures with abnormal accumulation of the ESCRT protein IST1 on the limiting membrane. VPS4A function was also required for normal endosomal morphology and IST1 localization in iPSC-derived human neurons. Mutations affected other ESCRT-dependent cellular processes, including regulation of centrosome number, primary cilium morphology, nuclear membrane morphology, chromosome segregation, mitotic spindle formation, and cell cycle progression. We thus characterize a distinct multisystem disorder caused by mutations affecting VPS4A and demonstrate that its normal function is required for multiple human developmental and cellular processes.


Subject(s)
ATPases Associated with Diverse Cellular Activities/genetics , Endosomal Sorting Complexes Required for Transport/genetics , Mutation, Missense , Neurodevelopmental Disorders/genetics , Vacuolar Proton-Translocating ATPases/genetics , Alleles , Animals , Brain/abnormalities , Cell Cycle , Centrosome/metabolism , Endosomes/metabolism , Fibroblasts/metabolism , Genomics , HEK293 Cells , HeLa Cells , Humans , Mice , Neurons/metabolism , Protein Domains , Protein Transport , Spindle Apparatus/metabolism
5.
Cell Mol Life Sci ; 77(13): 2641-2658, 2020 Jul.
Article in English | MEDLINE | ID: mdl-31587092

ABSTRACT

Mutations in the gene encoding the microtubule severing ATPase spastin are the most frequent cause of hereditary spastic paraplegia, a genetic condition characterised by length-dependent axonal degeneration. Here, we show that HeLa cells lacking spastin and embryonic fibroblasts from a spastin knock-in mouse model become highly polarised and develop cellular protrusions. In HeLa cells, this phenotype was rescued by wild-type spastin, but not by forms unable to sever microtubules or interact with endosomal ESCRT-III proteins. Cells lacking the spastin-interacting ESCRT-III-associated proteins IST1 or CHMP1B also developed protrusions. The protrusion phenotype required protrudin, a RAB-interacting protein that interacts with spastin and localises to ER-endosome contact sites, where it promotes KIF5-dependent endosomal motility to protrusions. Consistent with this, the protrusion phenotype in cells lacking spastin also required KIF5. Lack or mutation of spastin resulted in functional consequences for receptor traffic of a pathway implicated in HSP, as Bone Morphogenetic Protein receptor distribution became polarised. Our results, therefore, identify a novel role for ESCRT-III proteins and spastin in regulating polarised membrane traffic.


Subject(s)
Cell Surface Extensions/metabolism , Endosomal Sorting Complexes Required for Transport/metabolism , Spastin/metabolism , Animals , Bone Morphogenetic Protein Receptors/metabolism , Cell Membrane/metabolism , Cell Polarity , Cell Surface Extensions/ultrastructure , Cells, Cultured , Fibroblasts/cytology , Fibroblasts/metabolism , Gene Knock-In Techniques , HeLa Cells , Humans , Kinesins/physiology , Mice , Protein Transport , Spastic Paraplegia, Hereditary/genetics , Spastin/genetics , Vesicular Transport Proteins/physiology
6.
Front Neurosci ; 13: 1179, 2019.
Article in English | MEDLINE | ID: mdl-31787869

ABSTRACT

The hereditary spastic paraplegias (HSPs) are genetic motor neuron diseases characterized by progressive degeneration of corticospinal tract axons. Mutations in SPAST, encoding the microtubule-severing ATPase spastin, are the most common causes of HSP. The broad SPAST mutational spectrum indicates a haploinsufficiency pathogenic mechanism in most cases. Most missense mutations cluster in the ATPase domain, where they disrupt the protein's ability to sever microtubules. However, several putative missense mutations in the protein's microtubule interacting and trafficking (MIT) domain have also been described, but the pathogenicity of these mutations has not been verified with functional studies. Spastin promotes endosomal tubule fission, and defects in this lead to lysosomal enzyme mistrafficking and downstream lysosomal abnormalities. We investigated the function of three disease-associated spastin MIT mutants and found that none was able to promote normal endosomal tubule fission, lysosomal enzyme receptor trafficking, or lysosomal morphology. One of the mutations affected recruitment of spastin to endosomes, a property that requires the canonical function of the MIT domain in binding endosomal sorting complex required for transport (ESCRT)-III proteins. However, the other mutants did not affect spastin's endosomal recruitment, raising the possibility of pathologically important non-canonical roles for the MIT domain. In conclusion, we demonstrate that spastin MIT mutants cause functional abnormalities related to the pathogenesis of HSP. These mutations do not directly affect spastin's microtubule-severing capacity, and so we identify a new molecular pathological mechanism by which spastin mutations may cause disease.

7.
Development ; 145(17)2018 09 12.
Article in English | MEDLINE | ID: mdl-30082270

ABSTRACT

Functional analyses of genes responsible for neurodegenerative disorders have unveiled crucial links between neurodegenerative processes and key developmental signalling pathways. Mutations in SPG4-encoding spastin cause hereditary spastic paraplegia (HSP). Spastin is involved in diverse cellular processes that couple microtubule severing to membrane remodelling. Two main spastin isoforms are synthesised from alternative translational start sites (M1 and M87). However, their specific roles in neuronal development and homeostasis remain largely unknown. To selectively unravel their neuronal function, we blocked spastin synthesis from each initiation codon during zebrafish development and performed rescue analyses. The knockdown of each isoform led to different motor neuron and locomotion defects, which were not rescued by the selective expression of the other isoform. Notably, both morphant neuronal phenotypes were observed in a CRISPR/Cas9 spastin mutant. We next showed that M1 spastin, together with HSP proteins atlastin 1 and NIPA1, drives motor axon targeting by repressing BMP signalling, whereas M87 spastin acts downstream of neuropilin 1 to control motor neuron migration. Our data therefore suggest that defective BMP and neuropilin 1 signalling may contribute to the motor phenotype in a vertebrate model of spastin depletion.


Subject(s)
Bone Morphogenetic Proteins/metabolism , Motor Neurons/cytology , Neuropilin-1/metabolism , Spastin/genetics , Zebrafish Proteins/genetics , Zebrafish/embryology , Animals , Axons/metabolism , COS Cells , CRISPR-Cas Systems/genetics , Cell Line , Cell Movement/genetics , Chlorocebus aethiops , GTP-Binding Proteins/metabolism , Gene Knockout Techniques , Humans , Membrane Proteins/metabolism , Protein Isoforms/genetics , Spastic Paraplegia, Hereditary/genetics , Spastin/biosynthesis , Zebrafish Proteins/biosynthesis
8.
Brain ; 141(5): 1286-1299, 2018 05 01.
Article in English | MEDLINE | ID: mdl-29481671

ABSTRACT

Many genetic neurological disorders exhibit variable expression within affected families, often exemplified by variations in disease age at onset. Epistatic effects (i.e. effects of modifier genes on the disease gene) may underlie this variation, but the mechanistic basis for such epistatic interactions is rarely understood. Here we report a novel epistatic interaction between SPAST and the contiguous gene DPY30, which modifies age at onset in hereditary spastic paraplegia, a genetic axonopathy. We found that patients with hereditary spastic paraplegia caused by genomic deletions of SPAST that extended into DPY30 had a significantly younger age at onset. We show that, like spastin, the protein encoded by SPAST, the DPY30 protein controls endosomal tubule fission, traffic of mannose 6-phosphate receptors from endosomes to the Golgi, and lysosomal ultrastructural morphology. We propose that additive effects on this pathway explain the reduced age at onset of hereditary spastic paraplegia in patients who are haploinsufficient for both genes.


Subject(s)
Epistasis, Genetic/genetics , Mutation/genetics , Nuclear Proteins/genetics , Spastic Paraplegia, Hereditary/genetics , Spastin/genetics , Adult , Age of Onset , CD8 Antigens/genetics , CD8 Antigens/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Female , Guanine Nucleotide Exchange Factors/genetics , Guanine Nucleotide Exchange Factors/metabolism , HeLa Cells/metabolism , HeLa Cells/ultrastructure , Humans , Lysosomal-Associated Membrane Protein 1/metabolism , Lysosomal-Associated Membrane Protein 1/ultrastructure , Lysosomes/metabolism , Lysosomes/ultrastructure , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Middle Aged , Nuclear Proteins/metabolism , Nuclear Proteins/ultrastructure , Protein Transport/genetics , Transcription Factors/genetics , Transcription Factors/metabolism
9.
J Agric Food Chem ; 65(48): 10542-10549, 2017 Dec 06.
Article in English | MEDLINE | ID: mdl-29129055

ABSTRACT

The level of hydrogen sulfide (H2S) can increase during abiotic storage of wines, and potential latent sources of H2S are still under investigation. We demonstrate that elemental sulfur (S0) residues on grapes not only can produce H2S during fermentation but also can form precursors capable of generating additional H2S after bottle storage for 3 months. H2S could be released from S0-derived precursors by addition of a reducing agent (TCEP), but not by addition of strong brine to induce release of H2S from metal sulfide complexes. The size of the TCEP-releasable pool varied among yeast strains. Using the TCEP assay, multiple polar S0-derived precursors were detected following normal-phase preparative chromatography. Using reversed-phase liquid chromatography and high-resolution mass spectrometry, we detected an increase in the levels of diglutathione trisulfane (GSSSG) and glutathione disulfide (GSSG) in S0-fermented red wine and an increase in the levels of glutathione S-sulfonate (GSSO3-) and tetrathionate (S4O62-) in S0-fermented white wine as compared to controls. GSSSG, but not S4O62-, was shown to evolve H2S in the presence of TCEP. Pathways for the formation of GSSSG, GSSG, GSSO3-, and S4O62- from S0 are proposed.


Subject(s)
Hydrogen Sulfide/metabolism , Wine/analysis , Yeasts/metabolism , Hydrogen Sulfide/chemistry , Sulfur/analysis , Sulfur/metabolism , Vitis/chemistry , Vitis/microbiology , Wine/microbiology
10.
J Cell Biol ; 216(5): 1337-1355, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28389476

ABSTRACT

Contacts between endosomes and the endoplasmic reticulum (ER) promote endosomal tubule fission, but the mechanisms involved and consequences of tubule fission failure are incompletely understood. We found that interaction between the microtubule-severing enzyme spastin and the ESCRT protein IST1 at ER-endosome contacts drives endosomal tubule fission. Failure of fission caused defective sorting of mannose 6-phosphate receptor, with consequently disrupted lysosomal enzyme trafficking and abnormal lysosomal morphology, including in mouse primary neurons and human stem cell-derived neurons. Consistent with a role for ER-mediated endosomal tubule fission in lysosome function, similar lysosomal abnormalities were seen in cellular models lacking the WASH complex component strumpellin or the ER morphogen REEP1. Mutations in spastin, strumpellin, or REEP1 cause hereditary spastic paraplegia (HSP), a disease characterized by axonal degeneration. Our results implicate failure of the ER-endosome contact process in axonopathy and suggest that coupling of ER-mediated endosomal tubule fission to lysosome function links different classes of HSP proteins, previously considered functionally distinct, into a unifying pathway for axonal degeneration.


Subject(s)
Endoplasmic Reticulum/metabolism , Endosomes/metabolism , Lysosomes/metabolism , Spastic Paraplegia, Hereditary/metabolism , Adult , Animals , Cells, Cultured , Female , HeLa Cells , Humans , Male , Mice , Middle Aged
11.
PLoS One ; 11(3): e0152413, 2016.
Article in English | MEDLINE | ID: mdl-27019090

ABSTRACT

The hereditary spastic paraplegias (HSPs) are genetic conditions in which there is progressive axonal degeneration in the corticospinal tract. Autosomal dominant mutations, including nonsense, frameshift and missense changes, in the gene encoding the microtubule severing ATPase spastin are the most common cause of HSP in North America and northern Europe. In this study we report quantitative gait analysis using a motorized treadmill system, carried out on mice knocked-in for a disease-associated mutation affecting a critical residue in the Walker A motif of the spastin ATPase domain. At 4 months and at one year of age homozygous mutant mice had a number of abnormal gait parameters, including in stride length and stride duration, compared to heterozygous and wild-type littermates. Gait parameters in heterozygous animals did not differ from wild-type littermates. We conclude that quantitative gait analysis using the DigiGait system sensitively detects motor abnormalities in a hereditary spastic paraplegia model, and would be a useful method for analyzing the effects of pharmacological treatments for HSP.


Subject(s)
Adenosine Triphosphatases/genetics , Gait/physiology , Spastic Paraplegia, Hereditary/physiopathology , Adenosine Triphosphatases/chemistry , Adenosine Triphosphatases/metabolism , Analysis of Variance , Animals , Axons/pathology , Cells, Cultured , Disease Models, Animal , Female , Gene Knock-In Techniques , Genotype , Heterozygote , Homozygote , Male , Mice , Mice, Inbred C57BL , Microscopy, Fluorescence , Mutation , Neurons/cytology , Neurons/metabolism , Neurons/pathology , Phenotype , Spastic Paraplegia, Hereditary/genetics , Spastin
12.
Article in English | MEDLINE | ID: mdl-26737881

ABSTRACT

The effect of miniaturizing the electrode lead for Deep Brain Stimulation (DBS) therapy was investigated in this work. A direct comparison was made between a miniature lead (0.65 mm diameter) and a lead of standard size (1.3 mm). Acute in vivo implantation in two cat brains was performed to evaluate surgical trauma and confirm capacity to target thalamic nuclei. Insertion into a homogeneous gel model of neural tissue was used to compare insertion forces while visualizing the process. The standard size cannula, used first to guide lead insertion, required substantially higher insertion force compared with the miniature version and produced a significantly larger region of tissue disruption. The characteristic hemorrhage and edema extended 119-352 µm from the implanted track surface of the miniature lead and cannula, while these extended 311-571 µm for the standard size lead and cannula. A miniature DBS implant can reduce the extent of trauma and could potentially help improve neural function preservation after functional neurosurgery.


Subject(s)
Deep Brain Stimulation/methods , Electrodes, Implanted , Animals , Brain/pathology , Brain/surgery , Cats , Geniculate Bodies/pathology , Microelectrodes , Neurosurgical Procedures
13.
Arthroscopy ; 30(1): 42-6, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24384272

ABSTRACT

PURPOSE: The purpose was to assess ultrasound-guided injections through patient satisfaction in a comparative internally controlled study of fluoroscopic versus ultrasound technique and to quantitate the reliability of the ultrasound method. In addition, the reliability of the ultrasound method was quantitated. METHODS: This study consisted of the first 50 consecutive patients to undergo ultrasound-guided intra-articular injection of the hip (by a nurse practitioner) and who had previously undergone fluoroscopy-guided intra-articular injections by our center's fellowship-trained musculoskeletal radiologists. The patients rated the ultrasound and fluoroscopic experiences on a scale from 1 to 10 for convenience and pain; in addition, they indicated their preference between the 2 techniques. Success of the injection was documented among a total of 206 consecutive patients who underwent ultrasound-guided injections during the period of the controlled study. RESULTS: For convenience, ultrasound injection had a mean rating of 9.8 whereas fluoroscopic injection had a mean rating of 3.1. For pain, ultrasound had a mean rating of 3 and fluoroscopy had a mean rating of 5.6. These differences were statistically significant (P < .01) in favor of ultrasound. For preference, 49 of 50 patients in the control study (98%) stated that they would prefer the ultrasound injection, whereas 1 was uncertain. The injection was successful in 202 of the first 206 patients (98%) to undergo ultrasound injection, whereas 4 patients required a second pass for successful injection. CONCLUSIONS: In this study in-office ultrasound-guided injections of the hip were more convenient and less painful than fluoroscopy-guided hospital-based injections and were preferred by patients who have undergone both. Furthermore, the ultrasound-guided injections were performed by a recently trained physician extender in contrast to the fluoroscopic method, which was performed by experienced fellowship-trained musculoskeletal radiologists. The procedure is highly successful in the hands of a properly trained clinician. LEVEL OF EVIDENCE: Level II, prospective comparative study.


Subject(s)
Hip Joint/diagnostic imaging , Injections, Intra-Articular/methods , Patient Preference/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Fluoroscopy , Humans , Prospective Studies , Reproducibility of Results , Surveys and Questionnaires , Ultrasonography
14.
J Cell Biol ; 202(3): 527-43, 2013 Aug 05.
Article in English | MEDLINE | ID: mdl-23897888

ABSTRACT

Mechanisms coordinating endosomal degradation and recycling are poorly understood, as are the cellular roles of microtubule (MT) severing. We show that cells lacking the MT-severing protein spastin had increased tubulation of and defective receptor sorting through endosomal tubular recycling compartments. Spastin required the ability to sever MTs and to interact with ESCRT-III (a complex controlling cargo degradation) proteins to regulate endosomal tubulation. Cells lacking IST1 (increased sodium tolerance 1), an endosomal sorting complex required for transport (ESCRT) component to which spastin binds, also had increased endosomal tubulation. Our results suggest that inclusion of IST1 into the ESCRT complex allows recruitment of spastin to promote fission of recycling tubules from the endosome. Thus, we reveal a novel cellular role for MT severing and identify a mechanism by which endosomal recycling can be coordinated with the degradative machinery. Spastin is mutated in the axonopathy hereditary spastic paraplegia. Zebrafish spinal motor axons depleted of spastin or IST1 also had abnormal endosomal tubulation, so we propose this phenotype is important for axonal degeneration.


Subject(s)
Adenosine Triphosphatases/metabolism , Endosomal Sorting Complexes Required for Transport/metabolism , Endosomes/metabolism , Microtubules/metabolism , Oncogene Proteins/metabolism , Adenosine Triphosphatases/chemistry , Animals , Cells, Cultured , Endosomal Sorting Complexes Required for Transport/chemistry , HeLa Cells , Humans , Oncogene Proteins/chemistry , Spastin , Zebrafish
15.
Soc Sci Res ; 42(5): 1191-206, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23859725

ABSTRACT

While sexual attitudes have liberalized in the past half century, research is mixed as to whether attitudes have become less gendered over time. Recent studies on college students' sexual and romantic relationships suggest that a sexual double standard continues to organize sexuality on many campuses. Data from the Online College Social Life Survey shed light on students' evaluation of casual sex, or "hooking up." In addition to exploring gendered attitudinal patterns, we use gender structure theory to explore how individual characteristics and normative expectations of campus group affiliations shape attitudes. While three quarters of students do not hold different standards for men and women's hooking up, attitudes are more conservative than liberal, with almost half of students losing respect for men and women who hook up "a lot." However, men are more likely to hold a traditional double standard, while women are more likely to espouse egalitarian conservative attitudes. Individual characteristics, including age, religion, race, social class and sexual orientation are frequently related to sexual attitudes, as are number of hook ups, fraternity/sorority affiliation and varsity athletic participation.

16.
J Clin Invest ; 122(2): 538-44, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22232211

ABSTRACT

Hereditary spastic paraplegias (HSPs) are a group of genetically heterogeneous neurodegenerative conditions. They are characterized by progressive spastic paralysis of the legs as a result of selective, length-dependent degeneration of the axons of the corticospinal tract. Mutations in 3 genes encoding proteins that work together to shape the ER into sheets and tubules - receptor accessory protein 1 (REEP1), atlastin-1 (ATL1), and spastin (SPAST) - have been found to underlie many cases of HSP in Northern Europe and North America. Applying Sanger and exome sequencing, we have now identified 3 mutations in reticulon 2 (RTN2), which encodes a member of the reticulon family of prototypic ER-shaping proteins, in families with spastic paraplegia 12 (SPG12). These autosomal dominant mutations included a complete deletion of RTN2 and a frameshift mutation predicted to produce a highly truncated protein. Wild-type reticulon 2, but not the truncated protein potentially encoded by the frameshift allele, localized to the ER. RTN2 interacted with spastin, and this interaction required a hydrophobic region in spastin that is involved in ER localization and that is predicted to form a curvature-inducing/sensing hairpin loop domain. Our results directly implicate a reticulon protein in axonopathy, show that this protein participates in a network of interactions among HSP proteins involved in ER shaping, and further support the hypothesis that abnormal ER morphogenesis is a pathogenic mechanism in HSP.


Subject(s)
Endoplasmic Reticulum/ultrastructure , Membrane Proteins/genetics , Muscle Proteins/genetics , Mutation , Nerve Tissue Proteins/genetics , Spastic Paraplegia, Hereditary/genetics , Spastic Paraplegia, Hereditary/pathology , Adenosine Triphosphatases/genetics , Adenosine Triphosphatases/metabolism , DNA Mutational Analysis , Endoplasmic Reticulum/metabolism , HEK293 Cells , HeLa Cells , Humans , Membrane Proteins/metabolism , Muscle Proteins/metabolism , Nerve Tissue Proteins/metabolism , Spastic Paraplegia, Hereditary/physiopathology , Spastin
17.
Biochim Biophys Acta ; 1823(1): 192-7, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21888932

ABSTRACT

In 1999, mutations in the gene encoding the microtubule severing AAA ATPase spastin were identified as a major cause of a genetic neurodegenerative condition termed hereditary spastic paraplegia (HSP). This finding stimulated intense study of the spastin protein and over the last decade, a combination of cell biological, in vivo, in vitro and structural studies have provided important mechanistic insights into the cellular functions of the protein, as well as elucidating cell biological pathways that might be involved in axonal maintenance and degeneration. Roles for spastin have emerged in shaping the endoplasmic reticulum and the abscission stage of cytokinesis, in which spastin appears to couple membrane modelling to microtubule regulation by severing.


Subject(s)
Adenosine Triphosphatases/metabolism , Cell Membrane/metabolism , Microtubules/metabolism , Adenosine Triphosphatases/chemistry , Adenosine Triphosphatases/genetics , Animals , Axons/enzymology , Axons/pathology , Endosomal Sorting Complexes Required for Transport/metabolism , Endosomes/metabolism , Humans , Mutation , Protein Structure, Tertiary , Spastic Paraplegia, Hereditary/enzymology , Spastic Paraplegia, Hereditary/genetics , Spastin
18.
Anal Chim Acta ; 703(1): 52-7, 2011 Oct 03.
Article in English | MEDLINE | ID: mdl-21843674

ABSTRACT

Rapid, inexpensive, and convenient methods for quantifying elemental sulfur (S(0)) with low or sub-µgg(-1) limits of detection would be useful for a range of applications where S(0) can act as a precursor for noxious off-aromas, e.g., S(0) in pesticide residues on winegrapes or as a contaminant in drywall. However, existing quantification methods rely on toxic reagents, expensive and cumbersome equipment, or demonstrate poor selectivity. We have developed and optimized an inexpensive, rapid method (∼15 min per sample) for quantifying S(0) in complex matrices. Following dispersion of the sample in PEG-400 and buffering, S(0) is quantitatively reduced to H(2)S in situ by dithiothreitol and simultaneously quantified by commercially available colorimetric H(2)S detection tubes. By employing multiple tubes, the method demonstrated linearity from 0.03 to 100 µg S(0) g(-1) for a 5 g sample (R(2)=0.994, mean CV=6.4%), and the methodological detection limit was 0.01 µg S(0) g(-1). Interferences from sulfite or sulfate were not observed. Mean recovery of an S(0) containing sulfur fungicide in grape macerate was 84.7% with a mean CV of 10.4%. Mean recovery of S(0) in a colloidal sulfur preparation from a drywall matrix was 106.6% with a mean CV of 6.9%. Comparable methodological detection limits, sensitivity, and recoveries were achieved in grape juice, grape macerate and with 1g drywall samples, indicating that the methodology should be robust across a range of complex matrices.

19.
Nucleic Acids Res ; 39(12): 5215-31, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21385827

ABSTRACT

Here, we report that the untreated rabbit reticulocyte lysate contains over 300 different endogenous microRNAs together with the major components of the RNA-induced silencing complex and thus can be used as a model in vitro system to study the effects of microRNAs on gene expression. By using this system, we were able to show that microRNA hybridization to its target resulted in a very rapid and strong inhibition of expression that was exerted exclusively at the level of translation initiation with no involvement of transcript degradation or deadenylation. Moreover, we demonstrate that the magnitude of microRNA-induced repression can only be recapitulated in the context of a competitive translating environment. By using a wide spectrum of competitor cellular and viral RNAs, we could further show that competition was not exerted at the level of general components of the translational machinery, but relied exclusively on the presence of the poly(A) tail with virtually no involvement of the cap structure.


Subject(s)
Gene Expression Regulation , MicroRNAs/metabolism , Peptide Chain Initiation, Translational , Poly A/metabolism , RNA, Messenger/metabolism , Animals , MicroRNAs/analysis , MicroRNAs/antagonists & inhibitors , Micrococcal Nuclease , Oligonucleotides , Protein Biosynthesis , RNA, Messenger/chemistry , RNA, Small Interfering/metabolism , RNA-Induced Silencing Complex/analysis , RNA-Induced Silencing Complex/metabolism , Rabbits , Reticulocytes/enzymology , Reticulocytes/metabolism
20.
Methods ; 51(1): 165-9, 2010 May.
Article in English | MEDLINE | ID: mdl-20188836

ABSTRACT

The tethered function assay is a method designed to address the role of an RNA-binding protein upon the metabolism of a reporter RNA. The basis of this assay is to artificially tether a test protein to a reporter mRNA by employing an unrelated bacteriophage MS2 or lambda N RNA-protein interaction, and to assess the effects of the test protein on the reporter RNA. In this chapter, we first discuss the principles and validity of the tethered function approach, drawing on appropriate examples from several cell types and of many proteins that regulate RNA in a variety of processes, including RNA processing (splicing, polyadenylation/deadenylation, decay), localisation and protein synthesis. Secondly, we will focus on the use of this approach to monitor translational activation and repression in Xenopus oocytes, giving a detailed protocol, and discussing possible optimizations we have explored.


Subject(s)
Gene Expression Regulation, Developmental , Oocytes/cytology , Protein Biosynthesis , Xenopus/metabolism , 3' Untranslated Regions , Animals , Genes, Reporter , Models, Genetic , Mutation , Oocytes/metabolism , Open Reading Frames , Protein Binding , RNA/metabolism , RNA, Messenger/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...