Estrategias didácticas para la enseñanza de la biología molecular y la biotecnología, en estudiantes de educación media

El proyecto tuvo como objetivo contribuir a la formación científica, desarrollo de habilidades y destrezas experimentales en estudiantes de educación media, mediante la realización de módulos experimentales en biología molecular y en biotecnología. Los estudiantes, a través de la metodología científica, resolvieron la situación problema de aislar, clonar y expresar un gen de interés industrial en una levadura. Para ello, manipularon y caracterizaron, citológica y bioquímicamente, los microorganismos empleados en el proyecto. Luego, aislaron, amplificaron y secuenciaron el gen que codifica por la enzima alfa-acetolactato descarboxilasa, a partir de un plásmido bacteriano. Posteriormente, clonaron el gen en un vector de expresión dual y, realizaron ensayos de transformación genética en levadura y, evaluaron la actividad enzimática, mediante ensayo in vitro

Cuantificación de papilas fungiformes en pacientes sanos

Objective: The study aims to quantify the density and the diameter of fungiform papillae (FP) in healthy patients of different age ranges.  Material and Methods: A dental chart of all participants was created, and subsequently informed consent was obtained from those who met the inclusion criteria (n = 16, 7 women and 9 men, from 8 to 57 years of age). Blue food-dye was applied to the back of their tongues, followed by a 12mm diameter metal ring that was placed in the anterior tongue dorsal surface, and photographs were taken3. The density of FP in the ring and the diameter of the largest FP within the circle were determined. Quantification and measurement were carried out in Photoshop digital program4. Data were analyzed descriptively using the STATA v12.0 program. The association between variables was determined by Student's t-test and Pearson's correlation, with a significance level of 5%.Results: The average FP density was 15 ± 7 PF / cm2, and the average of the largest FP diameter was 0.74 ± 0.1mm. The age of the patients was negatively correlated with the FP density (R = -0.56, p = 0.02) and positively with the mean of the largest FP diameter (R = 0.56, p = 0.02). There was no significant association found between density and the mean number of the largest diameter of PF with the sex of the participants.Conclusion: The density and the largest diameter of FP are negatively and positively correlated with the age of the patients, respectively. Objetivo: El objetivo del estudio es cuantificar la densidad y el diámetro mayor de papilas fungiformes en pacientes sanos de distintos rangos etarios. Materiales y métodos: Se realizó una ficha clínica a los participantes, posteriormente, se hizo toma de consentimiento informado a las personas que cumplieran con requisitos de inclusión y exclusión. Se aplicó colorante azul de comida en el dorso lingual, luego, se ubicó un aro metálico de 12mm de diámetro en el sector anterior de la cara dorsal de la lengua y se tomaron fotografías3. Posteriormente, se determinó densidad de papilas fungiformes (PF) en el aro y el diámetro mayor de cada PF dentro del círculo. Cuantificación y medición se realizó en programa digital Photoshop, siguiendo criterios previamente descritos4. Con el programa STATA v12.0 se analizaron los datos descriptivamente. La asociación entre variables se determinó mediante test t de Student y correlación de Pearson, con un nivel de significación del 5%. Resultados: El promedio de densidad de PF fue de 15 ± 7 PF/cm² y el promedio del diámetro mayor de PF fue de 0,74 ± 0,1mm. La edad de los pacientes se correlacionó negativamente con la densidad de PF (R=-0,56 p=0,02) y positivamente con el promedio del diámetro mayor de PF (R=0,56,p=0.02). No se encontró asociación significativa entre densidad y promedio del diámetro mayor de PF con el sexo de los participantes. Conclusión: La densidad y el diámetro mayor de PF se correlacionan de forma negativa y positiva con la edad de los pacientes, respectivamente

Patterns and variability in electrophoretic polypeptide profiles of human saliva in a healthy population

Electrophoretic polypeptide profiles of normal human saliva differ markedly between different reports. Since both methodological variations and polymorphism may explain these differences, in this study we aimed to establish whether or not the salivary electrophoretic polypeptide profiles of subjects from a healthy population share discrete molecular features. To this end, parotid, submandibular/sublingual and whole salivas were collected separately from each of 40 young and 34 elderly clinically healthy adults and processed for SDS-polyacrylamide gel electrophoresis and Coomassie blue staining. Each type of glandular saliva displayed a different group of invariant (i.e. present in every subject) electrophoretic polypeptide bands while whole saliva showed a profile that reflected mostly the combined contribution of the major salivary glands. Some minor variant (i.e. absent in some subjects) bands were identified in each type of saliva. Regarding those interindividual variations, no age

Prevalence of Candida albicans and carriage of Candida non-albicans in the saliva of preschool children, according to their caries status

Objective: This study was conducted to establish associations among the Candida carriage rate, the diversity of Candida species carried and the different caries status of preschool children. Materials and methods: Sixty-one children between 2 and 5 years of age were examined by a single expert examiner and were divided into three groups, the caries-free, moderate caries and severe caries groups, according to the criteria of the International Caries Detection and Assessment System II (ICDAS). Saliva samples were obtained from the members of each group and were plated on Sabouraud agar plates to assess the Candida carriage rates. CHROMagar Candida medium was used for the preliminary screening. Biochemical testing or PCR/sequencing was conducted to identify the different Candida species in the samples. The differences observed were considered significant if the p value was <0.05. Results: The Candida carriage rate and the number of species of this fungus carried were higher in the group with the highest level of caries severity (p < 0.05). Whereas Candida albicans was the most predominant Candida species in the saliva of all of the children, C. dubliniensis was identified only in the most caries-affected group in addition to other rare species of Candida non-albicans. Conclusions: A high salivary Candida carriage rate and the presence of specific species of this fungus (such as C. albicans and C. dubliniensis) appear to be related to the severity of caries experienced by preschool children

Direct molecular analysis of FMR-1 gene mutation in patients with fragile Xq syndrome and their families Análisis molecular directo de mutaciones en el gen FMR-1 en pacientes con Síndrome de Xq frágil y sus familias

Background: The unequivocal diagnosis of fragile Xq syndrome is based in the direct analysis of the underlying FMR-1 gene mutation, that consists in an increased number of trinucleotide CGG repetitions. Aim: To study families with fragile Xq syndrome, using the Southern technique for the analysis of the mutation. Subjects and methods: Fifteen individuals, pertaining to 6 families with fragile Xq syndrome, were studied. Clinical, cytogenetic and molecular analysis using Southern technique, were done. Results: Five male individuals had a clinically evident syndrome, confirmed by cytogenetic analysis that showed fragility in 10 to 29% of studied cells. One subject with a clinical picture suggesting fragile Xq had a normal cytogenetic study. The other studied subjects were the mothers of the five subjects with the syndrome, that must be carriers, and four brothers. Molecular analysis showed that seven subjects (5 males) had a complete mutation, five (4 females) were carriers of a pre muta

Molecular alterations of parotid saliva in infantile chronic recurrent parotitis

Infantile chronic recurrent parotitis (ICRP) is an insidious disease whose etiopathogenesis remains an enigma. Alterations in the physical appearance of parotid saliva from ICRP patients have been frequently reported. However, sialochemical studies in regard to ICRP are very rare. The aim of this study was to determine whether saliva of ICRP patients presents major physicochemical and biochemical alterations compared with saliva from paired healthy controls. Parotid, whole, and submandibular/sublingual saliva was collected at an asymptomatic stage from 33 ICRP patients (5-16 y old, both sexes) and from 33 sex- and age-matched healthy controls. Saliva was analyzed for protein concentration, mode of protein diffusion on cellulose membranes, unidimensional sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis protein profiles and zymographic profiles of metalloproteinase 2 (MMP-2) and metalloproteinase 9 (MMP-9). Parotid saliva of ICRP patients showed an increased protein concen

Evaluation of the effectiveness of a chamomile (Matricaria chamomilla) and linseed (Linum usitatissimum) saliva substitute in the relief of xerostomia in elders

© 2016 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd Objective: The aim of this study was to determine the efficacy of a chamomile (Matricaria chamomilla) and linseed (Linum usitatissimum) saliva substitute in the relief of xerostomia in older participants. Background: In elders, xerostomia is a permanent and progressive condition that significantly affects their quality of life. The treatment for progressive xerostomia is currently restricted to palliative measures, and saliva substitutes are indicated. A lack of evidence on the effectiveness of the saliva substitutes in the relief of symptoms of xerostomia has been reported. Materials and methods: Seventy-four elderly participants presenting xerostomia of diverse origin were selected. Herbal saliva substitute and carboxymethyl cellulose conventional saliva substitute were tested using a double-blind, randomised, cross-sectional clinical trial. Results: Every participant of the study exhi

Diversity, frequency and antifungal resistance of Candida species in patients with type 2 diabetes mellitus

Objective: To determine number, species of Candida and Candida resistance to antifungal therapy according to the metabolic control state and the associated salivary changes in patients with type 2 diabetes mellitus (DM2). Materials and methods: Samples of non-stimulated saliva were collected from 52 patients with DM2. Salivary pH was measured and cultured on Sabouraud glucose agar and the values of CFU/ml were calculated. The species were presumptively identified using CHROMagar Candida® plates, and identification was confirmed by polymerase chain reaction (PCR). C. albicans isolates were cultured on SGA tetracycline agar with nystatin and fluconazole diffusion disks to measure susceptibility. Results: Sixty six percent of the yeasts isolated were Candida albicans, followed by C. glabrata (20.7%). In patients with decompensated DM2, there was an inverse association between HbA1c value and salivary pH. At higher levels of salivary acidification, a greater diversity and quantity of yeasts of the genus Candida were observed. With nystatin, higher inhibition was observed at lower pH. Conclusions: The antifungal therapies could be more effective if it consider, qualitative salivary characteristics as pH, that could determine the susceptibility of species of Candida to at least to nystatin, which is the most used antifungal for treatment to oral candidiasis in patients with DM2