In Vivo Tracking and 3D Mapping of Cell Death in Regeneration and Cancer Using Trypan Blue.

Tracking cell death in vivo can enable a better understanding of the biological mechanisms underlying tissue homeostasis and disease. Unfortunately, existing cell death labeling methods lack compatibility with in vivo applications or suffer from low sensitivity, poor tissue penetration, and limited temporal resolution. Here, we fluorescently labeled dead cells in vivo with Trypan Blue (TBlue) to detect single scattered dead cells or to generate whole-mount three-dimensional maps of large areas of necrotic tissue during organ regeneration.

Whole-Mount Histochemical Protocols in Zebrafish for a Hands-On Developmental Biology Practical Course in Ecuador.

Research-based education at the undergraduate level is ideal for fostering the training of future scientists. In an undergraduate Developmental Biology course, this learning strategy requires the availability of model species and enough research reagents, not only for technique training but also for the development of student original projects. This might be challenging in most countries, where resources are limited.

Direct development or endotrophic tadpole? Morphological aspects of the early ontogeny of the plump toad Osornophryne occidentalis (Anura: Bufonidae).

Andean Toads of the genus Osornophryne are suspected to have direct development on the basis of clutch and egg features. In this work, we describe the morphology of Osornophryne occidentalis embryos from a nest collected in the field. Several traits are similar to those reported in brachycephaloid Eleutherodactylus coqui and other direct-developing lineages.

Visual Signaling in the Semi-Fossorial Lizard (Gymnophthalmidae).

It has been suggested that gymnophthalmids, like most semi-fossorial lacertoids, rely more in chemical cues to communicate, in comparison to other groups, like Iguanids, on which communication is mostly based on visual signaling. We present the first description of visual signaling in the Andean lizard (Gymnophthalmidae) and a complete ethogram based on ex situ observations (34 different types of behaviors including positions and simple movements). Through the design of conspecific stimulus experiments, we were able to recognize leg-waving as a visual signal, as it is only displayed in presence of conspecifics or in presence of a mirror and was one of first and most frequent displays in this context.

Adaptive cell invasion maintains lateral line organ homeostasis in response to environmental changes.

Mammalian inner ear and fish lateral line sensory hair cells (HCs) detect fluid motion to transduce environmental signals. Actively maintained ionic homeostasis of the mammalian inner ear endolymph is essential for HC function. In contrast, fish lateral line HCs are exposed to the fluctuating ionic composition of the aqueous environment.

A polymorphism in oocyte pigmentation in natural populations of the glass frog (Centrolenidae).

The adaptive role of amphibian oocyte melanic pigmentation and its molecular control are still elusive. Here we present evidence of a polymorphism in egg pigmentation in the emerald glass frog . In Ecuadorian natural populations of this species, females can lay dark brown or pale eggs that develop into normal pigmented tadpoles and adults.

scRNA-Seq reveals distinct stem cell populations that drive hair cell regeneration after loss of Fgf and Notch signaling.

Loss of sensory hair cells leads to deafness and balance deficiencies. In contrast to mammalian hair cells, zebrafish ear and lateral line hair cells regenerate from poorly characterized support cells. Equally ill-defined is the gene regulatory network underlying the progression of support cells to differentiated hair cells.

Embryonic Development in the Peppermint Shrimp, Lysmata boggessi (Caridea: Lysmatidae).

There are a limited number of model species for decapod experimental embryology. To improve our understanding of developmental pattern evolution in the Decapoda, here we describe the early embryonic development of the caridean shrimp Lysmata boggessi, from immediately after fertilization to the hatching of the zoea larva, using fluorescence microscopy and whole-mount nuclear staining with 4',6-diamidino-2-phenylindole. Lysmata boggessi follows the standard caridean pattern of early development, with early holoblastic cleavage that will later become superficial, to form a blastoderm.

Regeneration of Sensory Hair Cells Requires Localized Interactions between the Notch and Wnt Pathways.

In vertebrates, mechano-electrical transduction of sound is accomplished by sensory hair cells. Whereas mammalian hair cells are not replaced when lost, in fish they constantly renew and regenerate after injury. In vivo tracking and cell fate analyses of all dividing cells during lateral line hair cell regeneration revealed that support and hair cell progenitors localize to distinct tissue compartments.

Gene-expression analysis of hair cell regeneration in the zebrafish lateral line.

Deafness caused by the terminal loss of inner ear hair cells is one of the most common sensory diseases. However, nonmammalian animals (e.g.

Embryogenesis and laboratory maintenance of the foam-nesting túngara frogs, genus Engystomops (= Physalaemus).

The vast majority of embryological research on amphibians focuses on just a single genus of frogs, Xenopus. To attain a more comprehensive understanding of amphibian development, experimentation on non-model frogs will be essential. Here, we report on the early development, rearing, and embryological analysis of túngara frogs (genus Engystomops, also called Physalaemus).

A comparative analysis of frog early development.

The current understanding of Xenopus laevis development provides a comparative background for the analysis of frog developmental modes. Our analysis of development in various frogs reveals that the mode of gastrulation is associated with developmental rate and is unrelated to egg size. In the gastrula of the rapidly developing embryos of the foam-nesting frogs Engystomops coloradorum and Engystomops randi, archenteron and notochord elongation overlapped with involution at the blastopore lip, as in X.