Using MetaboAnalyst to introduce undergraduates to lipidomic analysis and lipid remodeling in barley roots.

Lipidomics is a discipline that focuses on the identification and quantification of lipids. Although a part of the larger omics field, lipidomics requires specific approaches for the analysis and biological interpretation of datasets. This article presents a series of activities for introducing undergraduate microbiology students to lipidomic analysis through tools from the web-based platform MetaboAnalyst. The students perform a complete lipidomic workflow, which includes experiment design, data processing, data normalization, and statistical analysis of molecular phospholipid species obtained from barley roots exposed to Fusarium macroconidia. The input data are provided by the teacher, but students also learn about the methods through which they were originally obtained (untargeted liquid chromatography coupled with mass spectrometry). The ultimate aim is for students to understand the biological significance of phosphatidylcholine acyl editing. The chosen methodology allows users who are not proficient in statistics to make a comprehensive analysis of quantitative lipidomic datasets. We strongly believe that virtual activities based on the analysis of such datasets should be incorporated more often into undergraduate courses, in order to improve students' data-handling skills for omics sciences.

Recovery from chilling modulates the acyl-editing of phosphatidic acid molecular species in barley roots (Hordeum vulgare L.).

In plants, lipid metabolism and remodelling are key mechanisms for survival under temperature stress. The present study attempted to compare the lipid profile in barley roots both under chilling stress treatment and in the subsequent recovery to stress. Lipids were obtained through a single-extraction method with a polar solvent mixture, followed by mass spectrometry analysis. The results indicate that lipid metabolism was significantly affected by chilling. Most of the glycerolipids analysed returned to control values during short- and long-term recovery, whereas several representative phosphatidic acid (PA) molecular species were edited during long-term recovery. Most of the PA molecular species that increased in the long-term had the same acyl chains as the phosphatidylcholine (PC) species that decreased. C34:2 and C36:4 underwent the most remarkable changes. Given that the mechanisms underlying the acyl-editing of PC in barley roots remain elusive, we also evaluated the contribution of lysophosphatidylcholine acyltransferases (HvLPCAT) and phospholipase A (HvPLA). In line with the aforementioned results, the expression of the HvLPCAT and HvPLA genes was up-regulated during recovery from chilling. The differential acyl-editing of PA during recovery, which involves the remodelling of PC, might therefore be a regulatory mechanism of cold tolerance in barley.

Using fluorescent lipids contributes to the active learning of principles underlying lipid signaling.

The concepts of phospholipase activity is often taught in undergraduate biology and biochemistry classes and reinforced in laboratory exercises. However, very rarely does the design of these exercises allow students to directly gain experience in the use of modern instruments such as digital imaging systems and fluorescence spectrophotometers. The laboratory exercise described here involves the use of fluorescent lipids to evaluate phospholipase activity. Students use thin layer chromatography (TLC) to understand how lipids change under different conditions (i.e. abiotic and biotic stress). They explore strategies to separate, visualize and quantify lipids by TLC, digital imaging, and fluorometry. They also have increased opportunities for hands-on practise with experimental design, liposome sample preparation, and implementation of instrumentation commonly used by experienced researchers; all while learning and applying fundamental concepts about lipids. © 2018 International Union of Biochemistry and Molecular Biology, 47(1):100-105, 2018.

Differential phosphatidic acid metabolism in barley leaves and roots induced by chilling temperature.

Phosphatidic acid (PA) is an important bioactive lipid that mediates chilling responses in barley. Modifications in the lipid composition of cellular membranes during chilling are essential to maintain their integrity and fluidity. First, we investigated the molecular species of PA present in leaves and roots by ESI-MS/MS, to evaluate the modifications that occur in response to chilling. We demonstrated that PA pools in leaves differ from PA fatty acid composition in roots. Compared with plants grown at 25 °C, the short-term and long-term chilling for 3 h and 36 h at 4 °C not produced significant changes in PA molecular species. The endogenous DAG and PA phosphorylation by in vitro DAG and PA kinase activities showed higher activity in leaves compared with that in root, and they showed contrasting responses to chilling. Similarly, PA removal by phosphatidate phosphohydrolase was tested, showing that this activity was specifically increased in response to chilling in roots. The findings presented here may be helpful to understand how the PA signal is modulated between tissues, and may serve to highlight the importance of knowing the basal PA pools in different plant organs.

Lipid signalling mediated by PLD/PA modulates proline and H2O2 levels in barley seedlings exposed to short- and long-term chilling stress.

Phospholipase D (PLD) hydrolyses phospholipids to yield phosphatidic acid (PA) and a head group, and is involved in responses to a variety of environmental stresses, including chilling and freezing stress. Barley responses to chilling stress (induced by incubating seedlings at 4 °C) are dynamic and the duration of stress, either short (0-180 min) or long-term (24-36 h) had a significant impact on the response. We investigated the roles of PLD/PA in responses of barley (Hordeum vulgare) seedlings to short and long-term chilling stress, based on regulation of proline and reactive oxygen species (ROS) levels. Short-term chilling stress caused rapid and transient increases in PLD activity, proline level, and ROS levels in young leaves. PLD has the ability to catalyse the transphosphatidylation reaction leading to formation of phosphatidylalcohol (preferentially, to PA). Pre-treatment of seedlings with 1-butanol significantly increased proline synthesis but decreased ROS (H2O2) formation. These observations suggest that PLD is a negative regulator of proline synthesis, whereas PA/PLD promote ROS signals. Exogenous PA pre-treatment reduced the proline synthesis but enhanced H2O2 formation. Effects of long-term chilling stress on barley seedlings differed from those of short-term chilling stress. E.g., PLD activity was significantly reduced in young leaves and roots, whereas proline synthesis and ROS signals were increased in roots. Exogenous ROS application enhanced proline level while exogenous proline application reduced ROS level and modulated some effects of long-term chilling stress. Our findings suggest that PLD contributes to signalling pathways in responses to short-term chilling stress in barley seedling, through regulation of the balance between proline and ROS levels. In contrast, reduced PLD activity in the response to long-term chilling stress did not affect proline level. Increased ROS levels may reflect an antioxidant system that is affected by chilling stress and positively compensated by changes in proline level. Implications of our findings are discussed in regard to adaptation strategies of barley seedlings to low temperatures.

Suicidio en el adulto mayor / Suicide in old people

Se realiza un estudio en el Centro de Medicina Legal Provincial de Guantánamo, con el propósito de caracterizar los suicidios ocurridos en el adulto mayor en la provincia de Guantánamo en los años 2010-2011. El total de casos estudiados es de 95, de los cuales 24 cumplen los criterios para la investigación. Se recogen los datos contenidos en las autopsias realizadas y los libros estadísticos del Centro de Medicina Legal Provincial. Se estudian las variables: grupos de edades, estado civil, escolaridad y tipos de suicidios según sexo. Predomina el suicidio en el sexo masculino, entre 60 y 69 años, solteros, de escolaridad primaria y como método más usado el ahorcamiento. Se recomienda realizar una intervención profiláctico-educativa con ancianos y familiares, acorde con los datos obtenidos, para trabajar sobre las causas evitables de muertes violentas con vistas a poder prevenirlas (AU)

A study is done in the Legal Medicinal Center of Guantanamo, in order to characterize the suicides in old people, Guantánamo from 2010 to 2011. The total number of cases 95, of which 24 were known about the criteria for research. The data were collected on the autopsies and statisticals books. Variables were studied: age groups, marital status, education and suicide rates by sex. Suicide predominated in males, between 60 and 69 years old, single, primary school and as most used method, the hanging. It is recommended, prophylactic-educational intervention with elderly relatives, according to the data obtained, to work on avoidable causes of violent deaths to prevent overlooking (AU)

Estado cognitivo-afectivo en ancianos de la Casa de Abuelos Provincial de Guantánamo / Cognitive-affective condition in old people at Grandparents´s home, Guantanamo city

Se realiza un trabajo descriptivo en la primera Casa de Abuelos Provincial de Guantánamo con el propósito de caracterizar el estado cognitivo-afectivo de los ancianos durante el año 2010. El universo está constituido por la totalidad de los ancianos seminternos. Se estudian las siguientes variables: causas de ingresos, factores macrosociales y microsociales de riesgo, estado cognitivo y afectivo. El dato primario proviene de las historias clínicas y entrevistas realizadas. Se obtuvo como resultados que la principal causa de ingreso fue el hecho de no tener familiares que los atiendan adecuadamente, siendo este también un riesgo microsocial que repercute negativamente. La pérdida de roles sociales es el riesgo macrosocial. La mayor parte de los ancianos no presenta deterioro cognitivo pero sí tiene algún grado de depresión, aunque por lo general ligero (AU)

A descriptive research is performed on the first grandparents´s home Guantanamo, city in order to characterize the cognitive-affective condition of old people in 2010. The universe consisted of all grandparents. The following variables were studied: causes of income, macro and micro social factors of risk, cognitive and affective condition . The primary data came from the medical records and interviews. Such analysis indicated that the main cause of admission was the fact that the family had not adequately care, and this is also a risk that adversely affected micro. The loss of social roles is the macro risk. Most of the old people not presented, cognitive impairment but some degree of depression, although generally light (AU)