Impaired wound healing is associated with aging and has significant effects on human health on an individual level, but also on the whole health-care sector. Deficient angiogenesis appears to be involved in the process, but the underlying biology is still poorly understood. This is at least partially being explained by complexity and costs in using mammalian aging models. To understand aging-related vascular biology of impaired wound healing, we used zebrafish and turquoise killifish fin regeneration models. The regeneration of caudal fin after resection was significantly reduced in old individuals in both species. Age-related changes in angiogenesis, vascular density and expression levels of angiogenesis biomarker VEGF-A were observed. Furthermore, the anti-angiogenic drug vascular endothelial growth factor receptor blocking inhibitor SU5416 reduced regeneration, indicating a key role for angiogenesis in the regeneration of aging caudal fin despite aging-related changes in vasculature. Taken together, our data indicate that these fish fin regeneration models are suitable for studying aging-related decline in wound healing and associated alterations in aging vasculature.

• Keywords
• Aging, Angiogenesis, Danio rerio, Fin, Nothobranchius furzeri, Regeneration, Turquoise killifish, VEGF, Wound healing, Zebrafish,
• MeSH
• Zebrafish * metabolism   MeSH
• Fundulidae * MeSH
• Wound Healing MeSH
• Humans MeSH
• Zebrafish Proteins MeSH
• Mammals metabolism   MeSH
• Aged MeSH
• Vascular Endothelial Growth Factor A metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Aged MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Zebrafish Proteins MeSH
• Vascular Endothelial Growth Factor A MeSH

Antagonistic interactions between hosts and parasites may drive the evolution of novel host defenses, or new parasite strategies. Host immunity is therefore one of the fastest evolving traits. But where do the novel immune traits come from? Here, we test for phylogenetic conservation in a rapidly evolving immune trait-peritoneal fibrosis. Peritoneal fibrosis is a costly defense against a specialist tapeworm, Schistocephalus solidus (Cestoda), expressed in some freshwater populations of threespine stickleback fish (Gasterosteus aculeatus, Perciformes). We asked whether stickleback fibrosis is a derived species-specific trait or an ancestral immune response that was widely distributed across ray-finned fish (Actinopterygii) only to be employed by threespine stickleback against the specialist parasite. We combined literature review on peritoneal fibrosis with a comparative experiment using either parasite-specific, or nonspecific, immune challenge in deliberately selected species across fish tree of life. We show that ray-finned fish are broadly, but not universally, able to induce peritoneal fibrosis when challenged with a generic stimulus (Alum adjuvant). The experimental species were, however, largely indifferent to the tapeworm antigen homogenate. Peritoneal fibrosis, thus, appears to be a common and deeply conserved fish immune response that was co-opted by stickleback to adapt to a new selective challenge.

• Keywords
• Actinopterygii, comparative experiment, immunity, peritoneal fibrosis, stickleback, vaccination,
• MeSH
• Cestoda * MeSH
• Cestode Infections * MeSH
• Phylogeny MeSH
• Fish Diseases * MeSH
• Immunity, Innate MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Embryo-environment interactions are of paramount importance during the development of all organisms, and impacts during this period can echo far into later stages of ontogeny. African annual fish of the genus Nothobranchius live in temporary pools and their eggs survive the dry season in the dry bottom substrate of the pools by entering a facultative developmental arrest termed diapause. Uniquely among animals, the embryos (encased in eggs) may enter diapause at three different developmental stages. Such a system allows for the potential to employ different regulation mechanisms for each diapause. We sampled multiple Nothobranchius embryo banks across the progressing season, species, and populations. We present important baseline field data and examine the role of environmental regulation in the embryonic development of this unique system. We describe the course of embryo development in the wild and find it to be very different from the typical development under laboratory conditions. Development across the embryo banks was synchronized within and across the sampled populations with all embryos entering diapause I during the rainy season and diapause II during the dry season. Asynchrony occurred at transient phases of the habitat, during the process of habitat desiccation, and at the end of the dry season. Our findings reveal the significance of environmental conditions in the serial character of the annual fish diapauses.

• Keywords
• bet‐hedging, dormancy, egg bank, facultative, phenotypic plasticity,
• Publication type
• Journal Article MeSH

Dietary alteration is one of the most universally effective aging interventions, making its standardization a fundamental need for model organisms in aging. In this dietetic study we address the current lack of standardized formulated diet for turquoise killifish Nothobranchius furzeri - a promising model organism. We first demonstrated that N. furzeri can be fully weaned at the onset of puberty onto a commercially available pelleted diet as the sole nutrition when kept in social tanks. We then compared nine somatic and six reproductive parameters between fish fed a typical laboratory diet - frozen chironomid larvae (bloodworms) and fish weaned from bloodworms to BioMar pellets. Both dietary groups had comparable somatic and reproductive performance. There was no difference between diet groups in adult body size, specific growth rate, condition or extent of hepatocellular vacuolation. Fish fed a pelleted diet had higher juvenile body mass and more visceral fat. Pellet-fed males had lower liver mass and possessed a lipid type of hepatocellular vacuolation instead of the prevailing glycogen-like vacuolation in the bloodworm-fed group. No considerable effect was found on reproductive parameters. The negligible differences between dietary groups and good acceptance of pellets indicate their suitability as a useful starting point for the development of standardized diet for Nothobranchius furzeri.

• MeSH
• Animal Husbandry standards   MeSH
• Diet standards   veterinary   MeSH
• Fundulidae physiology   MeSH
• Animal Feed standards   MeSH
• Models, Animal * MeSH
• Body Composition MeSH
• Aging * MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The turquoise killifish, Nothobranchius furzeri, is a promising vertebrate model in ageing research and an emerging model organism in genomics, regenerative medicine, developmental biology and ecotoxicology. Its lifestyle is adapted to the ephemeral nature of shallow pools on the African savannah. Its rapid and short active life commences when rains fill the pool: fish hatch, grow rapidly and mature in as few as two weeks, and then reproduce daily until the pool dries out. Its embryos then become inactive, encased in the dry sediment and protected from the harsh environment until the rains return. This invertebrate-like life cycle (short active phase and long developmental arrest) combined with a vertebrate body plan provide the ideal attributes for a laboratory animal.

• Keywords
• Ageing, Natural History, Nothobranchius furzeri, Senescence, The Natural History of Model Organisms, Turquoise killifish, ecology, evolutionary biology,
• MeSH
• Cyprinodontiformes genetics   growth & development   physiology   MeSH
• Diet MeSH
• Ecosystem * MeSH
• Embryo, Nonmammalian physiology   MeSH
• Models, Animal MeSH
• Pigmentation MeSH
• Sexual Behavior, Animal MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Senescence in wild populations was long considered negligible but current evidence suggests that it is widespread in natural populations of mammals and birds, affecting the survival and reproductive output of older individuals. In contrast, little is known about reproductive senescence in species with asymptotic growth that can keep increasing their reproductive output as they grow older and larger. Using a cross-sectional study, we tested age-related decline in fecundity and relative allocation to reproduction in five wild populations of an annual killifish, Nothobranchius furzeri (Cyprinodontiformes). We did not detect any decline in absolute female egg production over their short lifespan in the wild. Relative fecundity (egg production controlled for female body mass) tended to decrease with age. This effect was driven primarily by a single population that survived 17 weeks, almost twice as long as the median persistence of the other four study populations. There was no decrease in relative ovary mass while in males, relative testes mass actually increased with age. Intra-population variation in relative ovary mass increased in older females suggesting heterogeneity in individual trajectories of female reproductive allocation. Overall, we demonstrate that annual killifish do not experience significant age-related decline in reproductive functions during their very short lifespan in the wild despite the marked deterioration of gonad tissue detected in captivity.

• Keywords
• Gene by environment interaction, Plasticity, Population heterogeneity, Reproductive ageing, Turquoise killifish,
• MeSH
• Cyprinodontiformes physiology   MeSH
• Animals, Wild MeSH
• Longevity physiology   MeSH
• Gonads physiology   MeSH
• Reproduction physiology   MeSH
• Aging MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

The natural history of model organisms is often overlooked despite its importance to correctly interpret the outcome of laboratory studies. Ageing is particularly understudied in natural populations. To address this gap, we present lifetime demographic data from wild populations of an annual species, the turquoise killifish, Nothobranchius furzeri, a model species in ageing research, and two other species of coexisting annual killifishes. Annual killifish hatch synchronously, have non-overlapping generations, and reproduce daily after reaching sexual maturity. Data from 13 isolated savanna pools in southern Mozambique demonstrate that the pools supporting killifish populations desiccated 1-4 months after their filling, though some pools persisted longer. Declines in population size over the season were stronger than predicted, because they exceeded the effect of steady habitat shrinking on population density that, contrary to the prediction, decreased. Populations of N. furzeri also became more female-biased with progressing season suggesting that males had lower survival. Nothobranchius community composition did not significantly vary across the season. Our data clearly demonstrate that natural populations of N. furzeri and its congeners suffer strong mortality throughout their lives, with apparent selective disappearance (condition-dependent mortality) at the individual level. This represents selective force that can shape the evolution of lifespan, and its variation across populations, beyond the effects of the gradient in habitat persistence.

• MeSH
• Cyprinodontiformes * genetics   physiology   MeSH
• Longevity MeSH
• Ecosystem MeSH
• Population Density MeSH
• Longitudinal Studies MeSH
• Sex Ratio MeSH
• Population Dynamics MeSH
• Seasons MeSH
• Sympatry MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Antipredator strategies increase the chances of survival of prey species but are subject to trade-offs and always come at a cost, one specific category being the "missed opportunity." Some animals that can modulate the timing of life-cycle events can also desynchronize this timing with the occurrence of a predator. In an unpredictable environment, such a modification may result in a mismatch with prevailing conditions, consequently leading to reproductive failure. In eastern Africa, temporary pools existing only during the rainy season are inhabited by annual fish of the genus Nothobranchius. We examined (i) the capability of multiple Nothobranchius populations and species to cease hatching when exposed to chemical cues from native fish predators and adult conspecifics and (ii) the ability of N. furzeri to modulate their growth rate in the presence of a gape-limited fish predator. As the tested Nothobranchius spp. originate from regions with extreme environmental fluctuations where the cost of a missed opportunity can be serious, we predicted an inability to cease hatching as well as lack of growth acceleration as both the predator's gape limitation and the environment select for the same adaptation. Our results showed no biologically relevant influence of kairomone on hatching and no influence on growth rate. This suggests that, in an unpredictable environment, the costs of a missed opportunity are substantial enough to prevent the evolution of some antipredator defense strategies.

• Keywords
• Clarias, diapause, embryo, olfactory cue, tilapia,
• Publication type
• Journal Article MeSH

The assembly of local communities from regional species pools is shaped by historical aspects of distribution, environmental conditions, and biotic interactions. We studied local community assembly patterns in African annual killifishes of the genus Nothobranchius (Cyprinodontiformes), investigating data from 168 communities across the entire range of regionally co-existing species. Nothobranchius are small fishes associated with annually desiccating pools. We detected a nested pattern of local communities in one region (Southern Mozambique, with Nothobranchius furzeri as the core and dominant species), but no nestedness was found in the second region (Central Mozambique, with Nothobranchius orthonotus being the dominant species). A checkerboard pattern of local Nothobranchius community assembly was demonstrated in both regions. Multivariate environmental niche modeling revealed moderate differences in environmental niche occupancy between three monophyletic clades that largely co-occurred geographically and greater differences between strictly allopatric species within the clades. Most variation among species was observed along an altitudinal gradient; N. furzeri and Nothobranchius kadleci were absent from coastal plains, Nothobranchius pienaari, Nothobranchius rachovii, and Nothobranchius krysanovi were associated with lower altitude and N. orthonotus was intermediate and geographically most widespread species. We discuss implications for ecological and evolutionary research in this taxon.

• Keywords
• Africa, altitudinal gradient, checkerboard pattern, dispersal, ephemeral pools, temporary water body,
• Publication type
• Journal Article MeSH

The evolution of life history is shaped by life expectancy. Life-history traits coevolve, and optimal states for particular traits are constrained by trade-offs with other life-history traits. Life histories contrast among species, but may also diverge intraspecifically, at the level of populations. We studied the evolution of female reproductive allocation strategy, using natural populations of two sympatric species of African annual fishes, Nothobranchius furzeri and Nothobranchius orthonotus. These species inhabit pools in the Mozambican savanna that are formed in the rainy season and persist for only 2-10 months. Using 207 female N. furzeri from 11 populations and 243 female N. orthonotus from 14 populations, we tested the effects of genetic background (intraspecific lineage) and life expectancy (position on the aridity gradient determining maximum duration of their temporary habitat) on female fecundity traits. First, we found that variation in female body mass was small within populations, but varied considerably among populations. Second, we found that fecundity was largely defined by female body mass and that females spawned most of their eggs in the morning. Third, we found that the trade-off between egg size and egg number varied among lineages of N. furzeri and this outcome has been confirmed by data from two separate years. Overall, we demonstrate that local conditions were important determinants for Nothobranchius growth and fecundity and that eggs size in arid region was less limited by female fecundity than in humid region.

• Keywords
• Annual killifish, egg size, interpopulation variation, intrapopulation variability, life expectancy, reproductive allocation,
• Publication type
• Journal Article MeSH