Effect of ATG12-ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion.

In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12-ATG5-ATG16L1 or E3-like complex (E3 for short) acts as a ubiquitin-like E3 enzyme, promoting LC3/GABARAP proteins anchoring to the AP membrane. Their role in the AP expansion process is still unclear, in part because there are no studies comparing six LC3/GABARAP family member roles under the same conditions, and also because the full human E3 was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through the formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulatory mechanism would allow vesicle incorporation and phagophore growth when E3 is present.

Role of defects in the mechanical properties of graphene-copper heterostructures.

Through molecular dynamics simulations of tensile tests, the role that vacancies and Stone-Wales defects play in the mechanical properties of sandwich-like heterostructures, composed by graphene and two symmetric copper layers at nanoscale, is studied. The dependence on the armchair and zigzag chiralities of the graphene layer is also investigated. During elastic deformation, defects negatively affect the mechanical response. However, defective systems can show an improvement of the plastic properties. Vacancies have a stronger impact compared to Stone-Wales defects. Elasticity, toughness, and ductility are enhanced along the zigzag chirality, while stiffness is improved along the armchair direction. The Poisson's ratio was calculated for all graphene-copper heterostructures. At a critical strain it becomes negative along the thickness direction, preserving the auxetic property at higher strains. In general, the behavior is governed by the graphene response. Our findings can be useful to understand the strengthening mechanism induced by this two-dimensional material in metals like copper and for the design of similar systems.

Management of odonto-stomatological emergencies during the COVID-19 alarm state in dental clinics in the Autonomous Community of Madrid (CAM), Spain: An observational study.

BACKGROUND: Odontology practice has been severely compromised by the pandemic caused by COVID-19 and Spain is one of the countries with higher incidence. Our aim with this study is to find out the number of cases and type of odonto-stomatological emergencies (OSE) treated in four dental clinics of the Madrid capital area and region (CAM) in the period covered between March 17th and 4th of May. MATERIAL AND METHODS: We search the cases in the demographic/epidemiological databases of the CAM regional government and the Illustrious Official College of Dentists and Stomatologists of the First Region (Madrid). RESULTS: We found that the most prevalent pathology was acute apical periodontitis whereas odontogenic abscess showed the lowest frequency. Prosthetic-orthodontic OSE represented 14% of cases. CONCLUSIONS: In this period of time, the most prevalent pathology acute apical periodontitis, odontogenic abscess reported the lowest frequency and prosthetic-orthodontic treatments were the third in number of cases. Most of OSE were resolved, without referring the patient to a hospital emergency department.

Lipid Geometry and Bilayer Curvature Modulate LC3/GABARAP-Mediated Model Autophagosomal Elongation.

Autophagy, an important catabolic pathway involved in a broad spectrum of human diseases, implies the formation of double-membrane-bound structures called autophagosomes (AP), which engulf material to be degraded in lytic compartments. How APs form, especially how the membrane expands and eventually closes upon itself, is an area of intense research. Ubiquitin-like ATG8 has been related to both membrane expansion and membrane fusion, but the underlying molecular mechanisms are poorly understood. Here, we used two minimal reconstituted systems (enzymatic and chemical conjugation) to compare the ability of human ATG8 homologs (LC3, GABARAP, and GATE-16) to mediate membrane fusion. We found that both enzymatically and chemically lipidated forms of GATE-16 and GABARAP proteins promote extensive membrane tethering and fusion, whereas lipidated LC3 does so to a much lesser extent. Moreover, we characterize the GATE-16/GABARAP-mediated membrane fusion as a phenomenon of full membrane fusion, independently demonstrating vesicle aggregation, intervesicular lipid mixing, and intervesicular mixing of aqueous content, in the absence of vesicular content leakage. Multiple fusion events give rise to large vesicles, as seen by cryo-electron microscopy observations. We also show that both vesicle diameter and selected curvature-inducing lipids (cardiolipin, diacylglycerol, and lyso-phosphatidylcholine) can modulate the fusion process, smaller vesicle diameters and negative intrinsic curvature lipids (cardiolipin, diacylglycerol) facilitating fusion. These results strongly support the hypothesis of a highly bent structural fusion intermediate (stalk) during AP biogenesis and add to the growing body of evidence that identifies lipids as important regulators of autophagy.

Fluorescent polyene ceramide analogues as membrane probes.

Three ceramide analogues have been synthesized, with sphingosine-like chains containing five conjugated double bonds. Pentaene I has an N-palmitoyl acyl chain, while the other two pentaenes contain also a doxyl radical, respectively, at C5 (Penta5dox) and at C16 (Penta16dox) positions of the N-acyl chain. Pentaene I maximum excitation and emission wavelengths in a phospholipid bilayer are 353 and 478 nm, respectively. Pentaene I does not segregate from the other lipids in the way natural ceramide does, but rather mixes with them in a selective way according to the lipid phases involved. Fluorescence confocal microscopy studies show that when lipid domains in different physical states coexist, Pentaene I emission is higher in gel than in fluid domains, and in liquid-ordered than in liquid-disordered areas. Electron paramagnetic resonance of the pentaene doxyl probes confirms that these molecules are sensitive to the physical state of the bilayer. Calorimetric and fluorescence quenching experiments suggest that the lipids under study orient themselves in lipid bilayers with their polar moieties located at the lipid-water interface. The doxyl radical in the N-acyl chain quenches the fluorescence of the pentaene group when in close proximity. Because of this property, Penta16dox can detect gel-fluid transitions in phospholipids. The availability of probes for lipids in the gel phase is important in view of novel evidence for the existence of gel microdomains in cell membranes.

A Study on the Knowledge, Perception, and Use of Breast Cancer Screening Methods and Quality of Care Among Women from Central Mexico.

Studies on health behaviors have observed several barriers to breast cancer screening, including lack of breast cancer knowledge, distrust of health care providers, and long waiting times to be screened or to receive screening results. We conducted a nested case-control study among a subsample of 200 women 21 years of age and older [100 patients (cases)], who had been diagnosed with breast cancer, and 100 controls, who were screened and found to be free of breast cancer), all residing in the Toluca metropolitan area in central Mexico. We examined how knowledge of breast cancer screening guidelines, perceptions of screening methods, and quality of health care influenced the use of breast cancer screening among study participants. Our study found that the most important factor associated with the decision to have breast cancer screenings was having a positive perception of the quality of care provided by the local health care centers, such as having competent clinic personnel, sufficient screening equipment, and reasonable waiting times to receive screening and to receive the screening results. Therefore, individual health care centers need to focus on the patients' perception of the services received by optimizing the care provided and, in so doing, increase the rates of early diagnosis and reduce the rate of mortality from breast cancer as well as its associated treatment costs.

Evolution of HIV-related stigma in Spain between 2008 and 2012.

To analyze the temporal evolution of HIV-related stigma in Spain between 2008 and 2012. We interviewed a representative sample of the Spanish population (N = 1619) through computer-assisted telephone interviews. The survey measures diverse facets of stigma and other-related variables. We compared the data of the 2012 survey with the result of the survey carried out in 2008. The degree of discomfort concerning people with HIV decreased significantly in 2012. Avoidance intention, negative feelings, the number of people who agreed with the implementation of harsh discriminatory policies, and the number of people who blame people with HIV were also lower in 2012. However, there are still misconceptions about HIV transmission. Attitudes of the Spanish population toward people with HIV have improved in the last four years. However, some attitudes and beliefs still need to be changed.

The importance of alpha/beta (alpha/13) interferon receptors and signaling pathways for the treatment of cervical intraepithelial neoplasias.

INTRODUCTION: Immunotherapies have been effective in treating various forms of cancer, including cervical intraepithelial neoplasias (CINs) predominantly caused by human papilloma virus (HPV). DEVELOPMENT: To establish persistent infections in stratified epithelia, HPV induces proliferative lesions. Viral gene products are able to change gene expression and cellular proteins. Interferons (IFNs) are inducible glycoproteins that have immunomodulatory, antiviral, antiproliferative, and antiangiogenic effects. In particular, interferon-alpha (IFN-alpha) has been shown to inhibit the development and progression of cervical cancer. In this review, actions of interferons alpha/beta (alpha/beta), including their receptors and signaling pathways, are described, as well as their clinical importance in the immune response against cervical lesions. CONCLUSION: The interaction of IFN-alpha/beta with its receptor results in a series of phosphorylation events. These mechanisms can be ineffective in IFN response, then it can also compromise the therapeutic effects of immunotherapy.

An evaluation of immune system cell infiltrate in the cervical stroma of patients with grade III cervical intraepithelial neoplasia after treatment with intralesional alpha-2B interferon.

The aim of this study was to characterize infiltrating immune cells in cervical stroma biopsy samples from patients diagnosed with cervical intraepithelial neoplasias (CINs) who were treated with IFN-alpha 2b. The authors studied 13 volunteers who were diagnosed with Cervical intraepithelial neoplasia CIN II or III and who received intra-lesional treatment with IFN-alpha 2b. They collected pre- and post-treatment biopsies from each patient. They also examined the slides under a common optical microscope with a X400 lens for biopsy sample sections that were labeled with immunohistochemistry for T lymphocyte, B lymphocyte, natural killer cell, macrophage, iNOS, and perforin markers. The presence of immune response cells in the lesion was observed after treatment with intralesional IFN-alpha 2b in patients with CIN II/III changes, a reduction in CD4+ and CD8+ T lymphocyte infiltration in the women who responded well to treatment. However, there was a significant increase in these markers in samples from women who did not respond to treatment. Nonetheless, immunotherapy with IFN-alpha 2b administered intralesionally in patients with CIN II/III yields favorable results in patients who do not smoke.

Vesicle-vesicle fusion promoted by the Atg8-family autophagy protein LC3C: relevance of the N-terminal region.

Among the MAP1LC3/LC3 subfamily of Atg8 proteins, LC3B and LC3C constitute the most and least studied members, respectively, LC3B being generally considered as an autophagosomal marker and a canonical representative of the LC3 subfamily. In several recent studies, LC3C has emerged as an important modulator in various processes of cell homeostasis. Our own research data demonstrate that LC3C induces higher levels of tethering and of intervesicular lipid mixing than LC3B. LC3C contains a peculiar N-terminal region, different from the other Atg8-family protein members. Using a series of mutants, we have shown that the N-terminal region of LC3C is responsible for the enhanced vesicle tethering, membrane perturbation and vesicle-vesicle fusion activities of LC3C as compared to LC3B.Abbreviations: ATG: autophagy related; GABARAP: gamma-aminobutyric acid receptor associated protein; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; PC: phosphatidyl choline; PE: phosphatidylethanolamine; PEmal: maleimide-derivatized PE; PtdIns: phosphatidylinositol.

Ceramide regulation of autophagy: A biophysical approach.

Specific membrane lipids play unique roles in (macro)autophagy. Those include phosphatidylethanolamine, to which LC3/GABARAP autophagy proteins become covalently bound in the process, or cardiolipin, an important effector in mitochondrial autophagy (or mitophagy). Ceramide (Cer), or N-acyl sphingosine, is one of the simplest sphingolipids, known as a stress signal in the apoptotic pathway. Moreover, Cer is increasingly being recognized as an autophagy activator, although its mechanism of action is unclear. In the present review, the proposed Cer roles in autophagy are summarized, together with some biophysical properties of Cer in membranes. Possible pathways for Cer activation of autophagy are discussed, including specific protein binding of the lipid, and Cer-dependent perturbation of bilayer properties. Cer generation of lateral inhomogeneities (domain formation) is given special attention. Recent biophysical results, including fluorescence and atomic force microscopy data, show Cer-promoted enhanced binding of LC3/GABARAP to lipid bilayers. These observations could be interpreted in terms of the putative formation of Cer-rich nanodomains.

The N-terminal region of the ATG8 autophagy protein LC3C is essential for its membrane fusion properties.

Autophagy is a catabolic process in which a double-membrane organelle, the autophagosome (AP), engulfs cellular components that will be degraded in the lysosomes. ATG8 protein family members participate at various stages of AP formation. The present study compares the capacity to induce lipid-vesicle tethering and fusion of two ATG8 family members, LC3B and LC3C, with model membranes. LC3B is the most thoroughly studied ATG8 protein. It is generally considered as an autophagosomal marker and a canonical representative of the LC3 subfamily. LC3C is less studied, but recent data have reported its implication in various processes, crucial to cellular homeostasis. The results in this paper show that LC3C induces higher levels of tethering and of intervesicular lipid mixing than LC3B. As the N-terminus of LC3C is different from that of the other family members, various mutants of the N-terminal region of both LC3B and LC3C were designed, and their activities compared. It was concluded that the N-terminal region of LC3C was responsible for the enhanced vesicle tethering, membrane perturbation and vesicle-vesicle fusion activities of LC3C as compared to LC3B. The results suggest a specialized function of LC3C in the AP expansion process.

Biological and chemical characterization in relation to the yield of radish (Raphanus sativus L.) nourished with humus from plant residues.

The increase in prices of fertilizers, energy and other materials necessary for the industry triggered a global economic crisis. Reason that was investigated on the biological and chemical characteristics in relation to the yield of radish nourished with humus from plant residue. The objective was to determine the appropriate dose of humus to obtain greater yield and its relationship with the chemical and biological characteristics of the radish. It is based on applied methodology with an experimental approach; Therefore, the Completely Random Block Design model was used, which consisted of 3 blocks and 5 treatments that were T1 with 0, T2 with 4, T3 with 6, T4 with 8 and T5 with 10 t/ha of humus and They applied 15 days after sowing. The physical characteristics of the radish were evaluated and processed using analysis of variance and Duncan. Concentration of elements in leaves and stomatal density were also analyzed. It was determined that T5 stood out in total plant length with 28.95 cm, plant weight with 76.87 g, equatorial diameter with 4,404 cm and commercial yield with 20,296 t/ha. Nitrogen consumption in relation to yield with 247.44 kg/ha. Stomatal density 459 stomata/mm2 and profitability with 150% and nutrient concentration in leaves highlighted T4 with N, K, Ca, Mg, Mo and Zn. It concludes that T5 stood out with 20,296 t/ha, which differed by 26.04% in relation to the control (T1) with 15,011 t/ha. Therefore, this dose added nutrients to the soil that improved the availability for plant absorption and this influenced the concentration of nutrients in leaves such as N, P and Fe and stomatal density with 459 stomata/mm2, which had a response in good development, strengthening against environmental stress and therefore greater performance.

Definition of unconformities based on radiometric tool.

The concentrations of U-238, Th-232, and K-40 measured with a portable gamma-ray spectrometer in cutting samples of two exploratory wells allowed the radiometric characterization of Cretaceous Rancheria sub-basin rocks and the definition of twelve (12) zones according to paleo-redox facies. The Th/Ua (authigenic uranium) and Th/U ratio greater than 7 (seven) indicates paleo-redox conditions related to oxygenation changes and detrital material input during deposition and terrestrial freshwater environment. However, the Lagunitas, Aguas Blancas, La Luna, and Molino formations characterize by facies from sub-oxic (dioxic) to anoxic redox. In the Aguas Blancas and Molino Formations, pyrite and the high uranium measurements determine an anoxic and euxinic environment. The high values of both + uranium and authigenic uranium in the La Luna and Molino formations relate to the conservation of organic matter, which is an essential factor in the generation of hydrocarbons. The abrupt changes of both K/U and Th/U identify potential sequential or genetic limit surfaces (e.g., maximum flooding surfaces), limiting such zones. Based on radiometric behavior, this research permitted identifying eight Cretaceous to Miocene unconformities in the area, three of them reported here for the first time.

Analysis of the biological and chemical characteristics of cabbage (Brassica oleracea var. Capitata L.) Fed with compost based on sugarcane residues.

The pandemic and the geopolitical conflict between Russia and Ukraine are events that have caused economic instability in Peru. Reason that was investigated on the analysis of the biological and chemical characteristics of cabbage fed with compost based on sugarcane residues. The objective was to analyze the physical, chemical and biological characteristics of cabbage from the adequate dose of compost based on sugarcane residues and distance between plants. It is based on the methodology applied with an experimental approach, for which the Completely Random Block Design with a 4x 2 factorial arrangement was used, which consisted of 3 blocks and 8 treatments that were the combination: F1 with 0, F2 with 8, T3 with 10 and F4 with 12 t/ha and spacing (D1) with 0.30 m between plants and 0.60 m between rows and (D2) with 0.35 m between plants and 0.60 m between rows. The physical characteristics of cabbage were evaluated and processed by analysis of variance, nutrient concentrations in leaves and stomatal density were analyzed. The results determined that T7 stood out in plant height with 41.88 cm, yield with 26.76 tn/ha and T6 in root length with 20.22 cm. In chemical analysis of leaves T1 stood out in nitrogen, phosphorus, potassium and T4 in calcium, magnesium and sulfur. In T7 stomata density with 977 stomata/mm2. It concludes that at an adequate dose and greater distance that T7 stands out in the concentration of nutrients that are within normal values and high density of stomata; Therefore, these characteristics influenced the optimal biochemical reactions, which obtained good development and yield that differed at 51.39% and 32.17% with respect to the controls T1 and T5.

Model systems of precursor cellular membranes: long-chain alcohols stabilize spontaneously formed oleic acid vesicles.

Oleic acid vesicles have been used as model systems to study the properties of membranes that could be the evolutionary precursors of more complex, stable, and impermeable phospholipid biomembranes. Pure fatty acid vesicles in general show high sensitivity to ionic strength and pH variation, but there is growing evidence that this lack of stability can be counterbalanced through mixtures with other amphiphilic or surfactant compounds. Here, we present a systematic experimental analysis of the oleic acid system and explore the spontaneous formation of vesicles under different conditions, as well as the effects that alcohols and alkanes may have in the process. Our results support the hypothesis that alcohols (in particular 10- to 14-C-atom alcohols) contribute to the stability of oleic acid vesicles under a wider range of experimental conditions. Moreover, studies of mixed oleic-acid-alkane and oleic-acid-alcohol systems using infrared spectroscopy and Langmuir trough measurements indicate that precisely those alcohols that increased vesicle stability also decreased the mobility of oleic acid polar headgroups, as well as the area/molecule of lipid.

LC3 subfamily in cardiolipin-mediated mitophagy: a comparison of the LC3A, LC3B and LC3C homologs.

Externalization of the phospholipid cardiolipin (CL) to the outer mitochondrial membrane has been proposed to act as a mitophagy trigger. CL would act as a signal for binding the LC3 macroautophagy/autophagy proteins. As yet, the behavior of the LC3-subfamily members has not been directly compared in a detailed way. In the present contribution, an analysis of LC3A, LC3B and LC3C interaction with CL-containing model membranes, and of their ability to translocate to mitochondria, is described. Binding of LC3A to CL was stronger than that of LC3B; both proteins showed a similar ability to colocalize with mitochondria upon induction of CL externalization in SH-SY5Y cells. Besides, the double silencing of LC3A and LC3B proteins was seen to decrease CCCP-induced mitophagy. Residues 14 and 18 located in the N-terminal region of LC3A were shown to be important for its recognition of damaged mitochondria during rotenone- or CCCP-induced mitophagy. Moreover, the in vitro results suggested a possible role of LC3A, but not of LC3B, in oxidized-CL recognition as a counterweight to excessive apoptosis activation. In the case of LC3C, even if this protein showed a stronger CL binding than LC3B or LC3A, the interaction was less specific, and colocalization of LC3C with mitochondria was not rotenone dependent. These results suggest that, at variance with LC3A, LC3C does not participate in cargo recognition during CL-mediated-mitophagy. The data support the notion that the various LC3-subfamily members might play different roles during autophagy initiation, identifying LC3A as a novel stakeholder in CL-mediated mitophagy. Abbreviations: ACTB/ß-actin: actin beta; Atg8: autophagy-related 8; CL: cardiolipin; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; DMSO: dimethyl sulfoxide; DOPE: 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine; DTT: DL-dithiothreitol; FKBP8: FKBP prolyl isomerase 8; GABARAP: GABA type A receptor associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GABARAPL2: GABA type A receptor associated protein like 2; GFP: green fluorescent protein; IMM: inner mitochondrial membrane; LUV/LUVs: large unilamellar vesicle/s; MAP1LC3A/LC3A: microtubule associated protein 1 light chain 3 alpha; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAP1LC3C/LC3C: microtubule associated protein 1 light chain 3 gamma; NME4/NDPK-D/Nm23-H4: NME/NM23 nucleoside diphosphate kinase 4; O/A: oligomycin A + antimycin A; OMM: outer mitochondrial membrane; PA: phosphatidic acid; PC: phosphatidylcholine; PG: phosphatidylglycerol; PINK1: PTEN induced putative kinase 1; PtdIns4P: phosphatidylinositol-4-phosphate; Rho-PE: lissamine rhodamine phosphatidylethanolamine; SUV/SUVs: small unilamellar vesicle/s.

Ceramide enhances binding of LC3/GABARAP autophagy proteins to cardiolipin-containing membranes.

Macroautophagy, or autophagy, is a process in which cell macromolecules, or even organelles, are engulfed in a double-membrane vesicle, the autophagosome, and directed to a lysosome. Among autophagy-related proteins, LC3/GABARAP constitute a protein family derived from yeast Atg8. They play important roles in autophagosome formation, binding future cargo organelles and promoting autophagosome growth. The involvement of specific lipids in this process is poorly understood. The present study explores the interaction of LC3/GABARAP proteins with phospholipid monolayers and bilayers based on phosphatidylcholine or on sphingomyelin. Cardiolipin is found to be essential for the protein interaction with such bilayers, as measured through gradient centrifugation experiments, while ceramide markedly increases binding. Giant unilamellar vesicles examined under confocal fluorescence microscopy reveal that ceramide segregates laterally into very rigid domains, while GABARAP binds only the more fluid regions, suggesting that the enhancing role of ceramide is exerted by the minority of ceramide molecules dispersed in the fluid phase. Although in further autophagy steps the LC3/GABARAP proteins are covalently bound to a phospholipid, this is not the case in our system, thus it is proposed that the observed ceramide effects would correspond to very early stages in the process, such as cargo recognition.

Autophagy protein LC3C binding to phospholipid and interaction with lipid membranes.

Autophagy is a process in which parts of the eukaryotic cell are selectively degraded in the lysosome. The materials to be catabolized are first surrounded by a double-membrane structure, the autophagosome. Autophagosome generation is a complex event, in which many proteins are involved. Among the latter, yeast Atg8 or its mammalian orthologues are essential in autophagosome membrane elongation, shaping and closure. A subfamily of the human Atg8 orthologues is formed by the proteins LC3A, LC3B, and LC3C. Previous studies suggest that, at variance with the other two, LC3C does not participate in cardiolipin-mediated mitophagy. The present study was devoted to exploring the binding of LC3C to lipid vesicles, bilayers and monolayers, and the ensuing protein-dependent perturbing effects, in the absence of the mitochondrial lipid cardiolipin. All Atg8 orthologues are covalently bound to a phospholipid prior to their involvement in autophagosome elongation. In our case, a mutant in the C-terminal amino acid, LC3C G126C, together with the use of a maleimide-derivatized phosphatidyl ethanolamine, ensured LC3C lipidation, up to 100% under certain conditions. Ultracentrifugation, surface pressure measurements, spectroscopic and cryo-electron microscopic techniques revealed that lipidated LC3C induced vesicle aggregation (5-fold faster in sonicated than in large unilamellar vesicles) and inter-vesicular lipid mixing (up to 82%), including inner-monolayer lipid mixing (up to 32%), consistent with in vitro partial vesicle fusion. LC3C was also able to cause the release of 80-90% vesicular aqueous contents. The data support the idea that LC3C would be able to help in autophagosome elongation/fusion in autophagy phenomena.

Perception and Knowledge of Mercury by Occupationally Exposed Health Care Personnel.

Thermometers and baumanometers frequently contain mercury, a toxic heavy metal. Inadequate management of this substance can constitute an occupational hazard by exposing health care professionals to health risks including memory loss, psychosomatic symptoms, fatigue, and other signs of cognitive dysfunction as reported in several studies. PURPOSE: To assess Mexico's health care professionals' health and mercury-related knowledge and risk perception and to explore the measurement properties of a questionnaire assessing that level of knowledge. MATERIALS AND METHODS: Mixed methodology. A quantitative, cross-sectional study was conducted to measure health care professionals' knowledge of mercury and to validate an instrument using a Rasch analysis in 160 professionals. A qualitative study involving in-depth interviews was conducted to identify participants' risk perception for mercury exposure. RESULTS: The total knowledge of mercury was 19.0 ± 2.0 on a scale of 0 to 28 points. The scores for medical specialists were significantly (P < .001) higher, ranging between 20.0 ± 2.05 and 23.0 ± 1.63. In general, the level of risk perception for mercury exposure was low. The questionnaire presented a reasonable fit to the Rasch model (good item fit with a Bonferroni-adjusted P = .000714). The response categories of three items were collapsed, and two pairs of items were bundled into two super items. CONCLUSION: The levels of the knowledge of the health and safety risks and risk perception for mercury exposure in the Mexican health care professionals evaluated were low. Health care professionals should receive comprehensive training in the safe use and health risks of mercury.