Breeding Annual, or Peat-Spawning Killies

Breeding Annual, or Peat-Spawning Killies

About peat

Peat, peat moss, garden peat, German peat, Canadian peat... what do they all mean?

Gas filling of the swimming bladder of south American annual fish larvae

The authors suggest that exercise is required to fill the swim bladder. Fry do not "take a gulp of air" to fill it as previously thought.

Incubation Times For Annual Killies

A table of incubation times for annual killifish. This table will tell you how long killifish egs take to hatch.

How moist is "moist peat" supposed to be?

The dampness of the peat can be critical in some species, here's an informal guide so you can refer to the dampness of peat in a way other killifans will know what you're talking about.

GABA metabolism is crucial for long-term survival of anoxia in annual killifish embryos

In most vertebrates, a lack of oxygen quickly leads to irreparable damages to vital organs, such as the brain and heart. However, there are some vertebrates that have evolved mechanisms to survive periods of no oxygen (anoxia). The annual killifish (Austrofundulus limnaeus) survives in ephemeral ponds in the coastal deserts of Venezuela and their embryos have the remarkable ability to tolerate anoxia for months. When exposed to anoxia, embryos of A. limnaeus respond by producing significant amounts of γ-aminobutyric acid (GABA). This study aims to understand the role of GABA in supporting the metabolic response to anoxia. To explore this, we investigated four developmentally distinct stages of A. limnaeus embryos that vary in their anoxia tolerance. We measured GABA and lactate concentrations across development in response to anoxia and aerobic recovery. We then inhibited enzymes responsible for the production and degradation of GABA and observed GABA and lactate concentrations, as well as embryo mortality. Here, we show for the first time that GABA metabolism affects anoxia tolerance in A. limnaeus embryos. Inhibition of enzymes responsible for GABA production (glutamate decarboxylase) and degradation (GABA-transaminase and succinic acid semialdehyde dehydrogenase) led to increased mortality, supporting a role for GABA as an intermediate product and not a metabolic end-product. We propose multiple roles for GABA during anoxia and aerobic recovery in A. limnaeus embryos, serving as a neurotransmitter, an energy source, and an anti-oxidant.

gaba: GABA metabolism is crucial for long-term survival of anoxia in annual killifish embryos

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