Hermaphrodite

Résumé

A hermaphrodite (hərˈmæfrəˌdaɪt) is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are of different sexes, either male or female but not both, are gonochoric, which is the opposite of hermaphroditic. The individuals of many taxonomic groups of animals, primarily invertebrates, are hermaphrodites, capable of producing viable gametes of both sexes. In the great majority of tunicates, mollusks, and earthworms, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. Hermaphroditism is also found in some fish species, but is rare or absent in other vertebrate groups. Most hermaphroditic species exhibit some degree of self-fertilization. The distribution of self-fertilization rates among animals is similar to that of plants, suggesting that similar pressures are operating to direct the evolution of selfing in animals and plants. A rough estimate of

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https://en.wikipedia.org/wiki/Hermaphrodite

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The theoretical part of this course covers classical genetics and contemporary genomics. Because bioinformatics has become important for genomic research, the course also includes practical applications to genomic analyses using Python, including group projects.

Understanding process and role of biomineralization (minerals formed by living organisms) in context of Earth's evolution,global chemical cycles, climatic changes and remediation.

Le but du cours est de fournir un aperçu général de la biologie des cellules et des organismes. Nous en discuterons dans le contexte de la vie des cellules et des organismes, en mettant l'accent sur les principes de réglementation que vous rencontrerez dans vos études de biologie.

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We introduce a new and simple microfluidic sorting device based on adjustable filter structures that can be easily tuned by external pressure for a specific size-dependent C. elegans worm sorting experiment. A single device can be used for selecting and sorting of all worm stages and single-sex populations on a microfluidic chip, in particular for sorting male and age-matched hermaphrodite C. elegans worms.

2016

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Like other animals, C. elegans nematodes have the ability to socially interact and to communicate through exchange and sensing of small soluble signaling compounds that help them cope with complex environmental conditions. For the time being, worm biocommunication assays are being performed mainly on agar plates; however, microfluidic assays may provide significant advantages compared to traditional methods, such as control of signaling molecule concentrations and gradients or confinement of distinct worm populations in different microcompartments. Here, we propose a microfluidic device for studying signaling via diffusive secreted compounds between two specific C. elegans populations over prolonged durations. In particular, we designed a microfluidic assay to investigate the biological process of maleinduced demise, i.e. lifespan shortening and accelerated age-related phenotype alterations, in C. elegans hermaphrodites in the presence of a physically separated male population. For this purpose, male and hermaphrodite worm populations were confined in adjacent microchambers on the chip, whereas molecules secreted by males could be exchanged between both populations by periodically activating the controlled fluidic transfer of mu l-volume aliquots of male-conditioned medium. For male-conditioned hermaphrodites, we observed a reduction of 4 days in mean lifespan compared to the non-conditioned on-chip culture. We also observed an enhanced muscle decline, as expressed by a faster decrease in the thrashing frequency and the appearance of vacuolar-like structures indicative of accelerated aging. The chip was placed in an incubator at 20 degrees C for accurate control of the lifespan assay conditions. An on-demand bacteria feeding protocol was applied, and the worms were observed during long-term on-chip culture over the whole worm lifespan.

Royal Soc Chemistry2016

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Fluctuations and deterioration in environmental conditions potentially have a phenotypic impact that extends over generations. Transgenerational epigenetics is the defined term for such intergenerational transient inheritance without an alteration in the DNA sequence. The model organism Caenorhabditis elegans is exceptionally valuable to address transgenerational epigenetics due to its short lifespan, well-mapped genome and hermaphrodite behavior. While the majority of the transgenerational epigenetics on the nematodes focuses on generations-wide heritage, short-term and in-depth analysis of this phenomenon in a well-controlled manner has been lacking. Here, we present a novel microfluidic platform to observe mother-to-progeny heritable transmission in C. elegans at high imaging resolution, under significant automation, and enabling parallelized studies. After approximately 24 hours of culture of L4 larvae under various concentrations and application periods of doxycycline, we investigated if mitochondria! stress was transferred from the mother nematodes to the early progenies. Automated and custom phenotyping algorithms revealed that a minimum doxycycline concentration of 30 mu g/mL and a drug exposure time of 15 hours applied to the mothers could induce mitochondria! stress in first embryo progenies indeed, while this inheritance was not clearly observed later in Ll progenies. We believe that our new device could find further usage in transgenerational epigenetic studies modeled on C. elegans.

2019

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