Abnormal ovipositor in a Drosophila melanogaster female

While collecting virgin females from a wild stock, we found a female with an abnormal ovipositor (Figures 1, abnormal; Figure 2, normal). The stock was obtained from wild D. melanogaster flies collected at the Font Groga site, near Barcelona, in autumn 2012 (Canals et al., 2013). Unfortunately, it was not possible to cross this female, and we did not have any information on her parents because she appeared in a mass culture [...]

Displaced genital arch in a Drosophila melanogaster male

Drosophila melanogaster mutant ebony (e) is characterized by its pigmentation defects in the adult cuticle (Bridges and Morgan, 1923); eyegone (eyg) has been described as having head and eyes much smaller than normal (Ives, 1942); and the vestigial (vg) locus seems to be only involved in wing development (Bridges and Morgan, 1919). While analyzing the F1 offspring from the parental cross between the D. melanogaster strains e eyg and vg, a particular fly was observed. It was a male, with no extended wings and normal color (although slightly darker because it was heterozygote for e). Interestingly, its genital arch was displaced from its normal position. It was not located in the ventral tip of the abdomen, instead it was displaced almost 90 degrees towards the end of the abdomen (Figures 1 and 2). The abdominal area where the genital arch should be was covered with a thin tegument (Figures 3 and 4). Sex combs were properly located. The animal died by accident nine days after emerging and left no progeny (he was caught in the culture medium) [...]

Les Planàries d'aigües dolces a Catalunya i les illes Balears. I. Clau sistemàtica i distribució geogràfica

The geographical distribution of freshwater planarians in Catalonia and the Balearic Islands has been studied from old and new records. Up to now, seven species have been found in Catalonia throughout the 44 localities studied, whereas only three species are present in the 13 localities studied in the Balearic Islands. The species and the geographical pattern found are similar to the published European records. The criteria for a correct diagnosis of planarian species are assessed especially when dealing with complex groups like the subgenera Schmidtea and the old «gonocephala» group. We stress the need to study the karyotypes to diagnose correctly some of the present species and to discover new races and species hidden under a similar external appearance. Taking into account these considerations a key is provided to assist clasification of these organisms. Finally, a pledge is made to stimulate the flow of sound information to add in a future work

Reactive oxygen species rescue regeneration after silencing the MAPK-ERK signaling pathway in Schmidtea mediterranea

Despite extensive research on molecular pathways controlling the process of regeneration in model organisms, little is known about the actual initiation signals necessary to induce regeneration. Recently, the activation of ERK signaling has been shown to be required to initiate regeneration in planarians. However, how ERK signaling is activated remains unknown. Reactive Oxygen Species (ROS) are well-known early signals necessary for regeneration in several models, including planarians. Still, the probable interplay between ROS and MAPK/ERK has not yet been described. Here, by interfering with major mediators (ROS, EGFR and MAPK/ERK), we were able to identify wound-induced ROS, and specifically H2O2, as upstream cues in the activation of regeneration. Our data demonstrate new relationships between regeneration-related ROS production and MAPK/ERK activation at the earliest regeneration stages, as well as the involvement of the EGFR-signaling pathway. Our results suggest that (1) ROS and/or H2O2 have the potential to rescue regeneration after MEK-inhibition, either by H2O2-treatment or light therapy, (2) ROS and/or H2O2 are required for the activation of MAPK/ERK signaling pathway, (3) the EGFR pathway can mediate ROS production and the activation of MAPK/ERK during planarian regeneration

CREB-binding protein (CBP) gene family regulates planarian survival and stem cell differentiation

In developmental biology, the regulation of stem cell plasticity and differentiation remains an open question. CBP(CREB-binding protein)/p300 is a conserved gene family that functions as a transcriptional co-activator and plays important roles in a wide range of cellular processes, including cell death, the DNA damage response, and tumorigenesis. The acetyl transferase activity of CBPs is particularly important, as histone and non-histone acetylation results in changes in chromatin architecture and protein activity that affect gene expression. Many studies have described the conserved functions of CBP/p300 in stem cell proliferation and differentiation. The planarian Schmidtea mediterranea is an excellent model for the in vivo study of the molecular mechanisms underlying stem cell differentiation during regeneration. However, how this process is regulated genetically and epigenetically is not well-understood yet. We identified 5 distinct Smed-cbp genes in S. mediterranea that show different expression patterns. Functional analyses revealed that Smed-cbp-2 appears to be essential for stem cell maintenance. On the other hand, the silencing of Smed-cbp-3 resulted in the growth of blastemas that were apparently normal, but remained largely unpigmented and undifferentiated. Smed-cbp-3 silencing also affected the differentiation of several cell lineages including neural, epidermal, digestive, and excretory cell types. Finally, we analysed the predicted interactomes of CBP-2 and CBP-3 as an initial step to better understand their functions in planarian stem cell biology. Our results indicate that planarian cbp genes play key roles in stem cell maintenance and differentiation

A hands-on genetics teaching approach at university level.

Teaching general Genetics is a cornerstone of a large number of university degrees. Being a scientific topic, laboratory classes are an essential element in student-centered learning. Here, we present our experience in implementing new material for teaching hands-on genetics, a subject of interest for other academic professionals in the field of Genetics. Our students carry out a genetic analysis of the su (sense ulls) mutation of Drosophila melanogaster, which produces a drastic eye reduction. The complete strain description can be found in Mestres et al. (2016a). The aim of the course is to give students the appropriate genetics tools to answer the three following questions: 1) Is the su mutation dominant or recessive? 2) In which chromosome is su located? 3) Can we identify in which gene the su mutation is

Descritpion of a double mutant strain of Drosophila melanogaster useful for genetic laboratory courses.

Many years ago, individuals showing drastically reduced eyes arose in our laboratory e (ebony) strain (Bridges and Morgan, 1923). We selected those flies presenting both traits and constituted a new double mutant strain e su (e, ebony; su, 'sense ulls', eyes drastically reduced). Both mutations were linked and located in the chromosome III. We used this strain in linkage analyses with our undergraduate students. [...

Smed-egfr-4 is required for planarian eye regeneration

ABSTRACT Planarians are remarkable organisms that can regenerate their entire body from a tiny portion thereof. This capability is made possible by the persistence throughout the lifespan of these animals of a population of pluripotent stem cells known as neoblasts. Planarian neoblasts include both pluripotent stem cells and specialized lineage-committed progenitors that give rise to all mature cell types during regeneration and homeostatic cell turnover. However, little is known about the mechanisms that regulate neoblast differentiation. A recent study demonstrated that Smed-egfr-1, a homologue of the epidermal growth factor receptor (EGFR) family, is required for final differentiation, but not specification, of gut progenitor cells into mature cells. Given the expression by planarians of several EGFR homologues, it has been proposed that these homologues may have diverged functionally to regulate the differentiation of distinct cell types in these animals. In this study, we investigated the role of Smed-egfr-4 in eye regeneration. Compared with controls, animals in which this gene was silenced by RNA interference (RNAi) regenerated smaller eyes. Moreover, the numbers of both mature eye cell types, photoreceptor neurons and cells of the pigment cup, were significantly reduced in Smed-egfr-4(RNAi) animals. By contrast, these animals exhibited an increase in the numbers of eye progenitor cells expressing the specific markers Smed-ovo and Smed-sp6-9. These results suggest that Smed-egfr-4 is required not for the specification of eye progenitor cells but for their final differentiation, and support the view that in planarians the EGFR pathway might play a general role in regulating the differentiation of lineage-committed progenitors

Smed-egfr-4 is required for planarian eye regeneration

ABSTRACT Planarians are remarkable organisms that can regenerate their entire body from a tiny portion thereof. This capability is made possible by the persistence throughout the lifespan of these animals of a population of pluripotent stem cells known as neoblasts. Planarian neoblasts include both pluripotent stem cells and specialized lineage-committed progenitors that give rise to all mature cell types during regeneration and homeostatic cell turnover. However, little is known about the mechanisms that regulate neoblast differentiation. A recent study demonstrated that Smed-egfr-1, a homologue of the epidermal growth factor receptor (EGFR) family, is required for final differentiation, but not specification, of gut progenitor cells into mature cells. Given the expression by planarians of several EGFR homologues, it has been proposed that these homologues may have diverged functionally to regulate the differentiation of distinct cell types in these animals. In this study, we investigated the role of Smed-egfr-4 in eye regeneration. Compared with controls, animals in which this gene was silenced by RNA interference (RNAi) regenerated smaller eyes. Moreover, the numbers of both mature eye cell types, photoreceptor neurons and cells of the pigment cup, were significantly reduced in Smed-egfr-4(RNAi) animals. By contrast, these animals exhibited an increase in the numbers of eye progenitor cells expressing the specific markers Smed-ovo and Smed-sp6-9. These results suggest that Smed-egfr-4 is required not for the specification of eye progenitor cells but for their final differentiation, and support the view that in planarians the EGFR pathway might play a general role in regulating the differentiation of lineage-committed progenitors

Les Planàries d'aigües dolces a Catalunya i les illes Balears. I. Clau sistemàtica i distribució geogràfica

The geographical distribution of freshwater planarians in Catalonia and the Balearic Islands has been studied from old and new records. Up to now, seven species have been found in Catalonia throughout the 44 localities studied, whereas only three species are present in the 13 localities studied in the Balearic Islands. The species and the geographical pattern found are similar to the published European records. The criteria for a correct diagnosis of planarian species are assessed especially when dealing with complex groups like the subgenera Schmidtea and the old «gonocephala» group. We stress the need to study the karyotypes to diagnose correctly some of the present species and to discover new races and species hidden under a similar external appearance. Taking into account these considerations a key is provided to assist clasification of these organisms. Finally, a pledge is made to stimulate the flow of sound information to add in a future work