Biparental inheritance of plastidial and mitochondrial DNA and hybrid variegation in Pelargonium

Plastidial (pt) and mitochondrial (mt) genes usually show maternal inheritance. Non-Mendelian, biparental inheritance of plastids was first described by Baur (Z Indukt Abstamm Vererbungslehre 1:330–351, 1909) for crosses between Pelargonium cultivars. We have analyzed the inheritance of pt and mtDNA by examining the progeny from reciprocal crosses of Pelargoniumzonale and P. inquinans using nucleotide sequence polymorphisms of selected pt and mt genes. Sequence analysis of the progeny revealed biparental inheritance of both pt and mtDNA. Hybrid plants exhibited variegation: our data demonstrate that the inquinans chloroplasts, but not the zonale chloroplasts bleach out, presumably due to incompatibility of the former with the hybrid nuclear genome. Different distribution of maternal and paternal sequences could be observed in different sectors of the same leaf, in different leaves of the same plant, and in different plants indicating random segregation and sorting-out of maternal and paternal plastids and mitochondria in the hybrids. The substantial transmission of both maternal and paternal mitochondria to the progeny turns Pelargonium into a particular interesting subject for studies on the inheritance, segregation and recombination of mt genes

Flipped classroom – A student perspective of an innovative teaching method during the times of pandemic

Background: Flipped Classroom is a blended form of learning in which the traditional didactic lectures are replaced by active classroom learning experience. Flipping the lectures outside the classroom and using the classroom for active interaction and projects has been the need of the hour. It is an innovative way of learning anatomy. Methods: The study was done at Department of Anatomy, ESIC Medical College, KK Nagar, Chennai. After obtaining ethical committee approval and Consent for participating in the study, Pre-test questionnaire was shared through Google forms. The lecture PowerPoint about anatomy of larynx was shared with the students. Next day, during the scheduled class, the students were asked to present anatomy of larynx using different types of models. Post-test questionnaires were also shared, and the students were asked to submit feedback forms at the end of the session. The students were assessed by a group of subject experts who assessed the student’s anatomical knowledge, innovation with which they prepared the model, presentation, correctness of presentation and clinical application. Results: Out of the 126 first year MBBS undergraduates, 100 students actively participated in the study. 41% of students agreed and 47% of students strongly agreed that flipped classroom was an enjoyable way of learning. 51% of students strongly agreed that they were able to go through the lecture prior to the presentation. Conclusions: Flipped classroom enhanced student learning through knowledge applications. Flipped classroom helped teachers to review and understand how much their students have read, retained, and applied the knowledge which was catered to them. There was largely a positive response for flipped classroom though flipped classroom cannot replace a regular classroom. Flipped classroom can be cumbersome as it involves extensive planning and coordination. It can be used to promote interest in the subject. Flipped classroom enhanced peer assisted learning. Resumen: Antecedentes: El Flipped Classroom es una forma mixta de aprendizaje en la que las clases didácticas tradicionales se sustituyen por una experiencia de aprendizaje activo en el aula. La necesidad de trasladar las clases fuera del aula y utilizar el aula para la interacción activa y los proyectos ha sido la necesidad del momento. Es una forma innovadora de aprender anatomía. Métodos: El estudio se llevó a cabo en el Departamento de Anatomía, ESIC Medical College, KK Nagar, Chennai. Después de obtener la aprobación del comité ético y el consentimiento para participar en el estudio, se compartió el cuestionario previo a la prueba a través del formulario de Google. Se compartió con los estudiantes el PowerPoint de la conferencia sobre la anatomía de la laringe. Al día siguiente, durante la clase programada, se pidió a los estudiantes que presentaran la anatomía de la laringe utilizando diferentes tipos de modelos. También se compartieron los cuestionarios posteriores a la prueba y se pidió a los alumnos que presentaran formularios de opinión al final de la sesión. Los alumnos fueron evaluados por un grupo de expertos en la materia que valoraron los conocimientos anatómicos del alumno, la innovación con la que prepararon el modelo, la presentación, la corrección de la exposición y la aplicación clínica. Resultados: De los 126 estudiantes de primer año de la MBBS, 100 alumnos participaron activamente en el estudio. El 41% de los estudiantes estaba de acuerdo y el 47% estaba muy de acuerdo en que el flipped classroom era una forma agradable de aprender. El 51% de los estudiantes estuvo muy de acuerdo en que pudieron repasar la clase antes de la presentación. Conclusiones: El flipped classroom mejoró el aprendizaje de los estudiantes mediante la aplicación de conocimientos. El flipped classroom ayudó a los profesores a revisar y comprender cuánto han leído, retenido y aplicado sus alumnos los conocimientos que les fueron impartidos. La respuesta a la flipped classroom fue mayoritariamente positiva, aunque la flipped classroom no puede sustituir a una clase normal. La clase invertida puede ser engorrosa, ya que implica una amplia planificación y coordinación. Puede utilizarse para fomentar el interés por la asignatura. La clase invertida mejora el aprendizaje asistido por los compañeros

FTIR and Thermal Studies on Nylon-66 and 30% Glass Fibre Reinforced Nylon-66

The present study deals with the characterization of the polymeric materials viz., nylon-66 and 30% glass fibre reinforced nylon-66 (GF Nylon-66) by employing FTIR and thermal measurements. The complete vibrational band assignment made available for nylon-66 and GF nylon-66 using FTIR spectra confirm their chemical structure. FTIR spectroscopy provides detailed information on polymer structure through the characteristic vibrational energies of the various groups present in the molecule. The thermal behavior of nylon-66 and GF nylon-66 essential for proper processing and fabrication was studied from TGA and DTA thermograms. The thermal stability of the polymers was studied from TGA and the activation energy for the degradation of the polymeric materials was calculated using Murray-White plot and Coats-Redfern plot. The polymer with high activation energy is more thermally stable. GF nylon-66 is found to be more thermally stable than nylon-66. The major thermal transitions such as crystalline melting temperature (Tm) and degradation temperature (Td) of the polymers were detected from DTA curves. The melting behaviour of the polymer depends upon the specimen history and in particular upon the temperature of crystallization. The melting behaviour also depends upon the rate at which the specimen is heated. The various factors such as molar mass and degree of chain branching govern the value of Tm in different polymers

Contrasting patterns of pollen and seed flow influence the spatial genetic structure of sweet vernal grass (<i>Anthoxanthum odoratum</i>) populations

The spatial genetic structure of plant populations is determined by a combination of gene flow, genetic drift, and natural selection. Gene flow in most plants can result from either seed or pollen dispersal, but detailed investigations of pollen and seed flow among populations that have diverged following local adaptation are lacking. In this study, we compared pollen and seed flow among 10 populations of sweet vernal grass (Anthoxanthum odoratum) on the Park Grass Experiment. Overall, estimates of genetic differentiation that were based on chloroplast DNA (cpDNA) and, which therefore resulted primarily from seed flow, were lower (average FST = 0.058) than previously published estimates that were based on nuclear DNA (average FST = 0.095). Unlike nuclear DNA, cpDNA showed no pattern of isolation by adaptation; cpDNA differentiation was, however, inversely correlated with the number of additions (nutrients and lime) that each plot had received. We suggest that natural selection is restricting pollen flow among plots, whereas nutrient additions are increasing seed flow and genetic diversity by facilitating the successful germination and growth of immigrant seeds. This study highlights the importance of considering all potential gene flow mechanisms when investigating determinants of spatial genetic structure, and cautions against the widespread assumption that pollen flow is more important than seed flow for population connectivity in wind-pollinated species

Under the rug: Abandoning persistent misconceptions that obfuscate organelle evolution

The advent and advance of next generation sequencing over the past two decades made it possible to accumulate large quantities of sequence reads that could be used to assemble complete or nearly complete organelle genomes (plastome or mitogenome). The result has been an explosive increase in the availability of organelle genome sequences with over 4000 different species of green plants currently available on GenBank. During the same time period, plant molecular biologists greatly enhanced the understanding of the structure, repair, replication, recombination, transcription and translation, and inheritance of organelle DNA. Unfortunately many plant evolutionary biologists are unaware of or have overlooked this knowledge, resulting in misrepresentation of several phenomena that are critical for phylogenetic and evolutionary studies using organelle genomes. We believe that confronting these misconceptions about organelle genome organization, composition, and inheritance will improve our understanding of the evolutionary processes that underly organelle evolution. Here we discuss four misconceptions that can limit evolutionary biology studies and lead to inaccurate phylogenies and incorrect structure of the organellar DNA used to infer organelle evolution