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 (r 2 = 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.
Sensory ethnographers deploy methods such as drawing, video and photography in order to examine the more ineffable and non-representational aspects of practices. Usually, these studies are conducted ...by individual researchers who deal only with their own material. What happens when a team of ethnographers explores questions of a sensory or non-representational nature? How do they share their findings not only with their audiences, but also with each other? Team ethnography is becoming increasingly common across the social sciences and humanities, yet to date there has been little attention paid to the important work of communicating findings within a group. To explore this further, we conducted a methodological ‘proof of concept’ study, observing and documenting people learning to make omelettes. We found that sensory methods have a role not only in studying practices but crucially, in also facilitating a form of immersion into the ethnographic practices and imaginations of others within the team. In the end, we suggest that experiments with sensory methods, such as through proof of concept methodological studies, are useful for thinking about how teams of social scientists work together, whether their research deals with sensory topics or not.
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 (S4O6 2–) in S0-fermented white wine as compared to controls. GSSSG, but not S4O6 2–, was shown to evolve H2S in the presence of TCEP. Pathways for the formation of GSSSG, GSSG, GSSO3 –, and S4O6 2– from S0 are proposed.
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.
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
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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.
A successful start to school correlates with positive later educational outcomes, both social and academic. Transitioning experience differs according to social context and this study was conducted ...in the UAE. Expatriate teachers, UAE national parents and expatriate parents were asked to complete a questionnaire of 20 child behaviours indicating the degree of agreement that each would indicate a successful transition. Differences according to role (teacher/parent) or culture (UAE national/expatriate) were found. The experience of transitioning is a highly context dependent phenomenon and each context warrants investigation to ensure as positive a start to school as possible for each child.
Objective
The aim of this analysis is to understand why young adult students in the US South marry in college or shortly afterwards.
Background
While the median age at first marriage in the United ...States has risen and marriage delay has become culturally normative, a substantial minority of young adults marry in their late teens or early 20's, particularly in the US South. Young adult college students who marry negotiate conflicting imperatives of marriage and educational attainment, and how these are negotiated or resolved sheds light on the social, cultural, and economic forces that inform family formation.
Method
This study draws from in‐depth interviews conducted with 45 18–23‐year‐old engaged or married college students in Mississippi.
Results
Entering college, most participants had expected to marry close to median ages, with marriage perceived as a hindrance to educational achievement. This marriage timeline was negotiated downwards with the influence of four interrelated factors: personal orientation to marriage; a marriage‐oriented culture, being in the “right” relationship; and social and financial supports for marriage.
Conclusion
The norm of marriage delay that these young adults embraced became perceived as inapplicable given evidence that marriage would not compromise college completion or financial stability. There were also social and cultural pressures toward marriage. “Why wait?” captures participants' sense of few barriers but clear incentives to marriage. Incentives were sometimes financial but also social, as marriage enabled students to establish themselves as more mature than peers.
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.
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.
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