Search

Many marine species have a pelagic larval phase that undergo dispersal among habitats. Studies on marine larval dispersal have revealed a large variation in the spatial scale of dispersal and self‐recruitment. However, few studies have investigated the influence of types of coastline (e.g., bay vs. open coast) on marine larval dispersal. Bays or lagoons generally enhance the retention of larvae, while larvae are more likely to be flushed by strong currents in open coasts. To examine associations between larval dispersal, coastline type, and hydrodynamics, we compared fin‐scale dispersal patterns, self‐recruitment, and local retention (LR) of two anemonefishes (Amphiprion frenatus and Amphiprion perideraion) between a semi‐enclosed bay and an open coast in the Philippines combining genetic parentage analysis and biophysical dispersal modeling. Contrary to our expectations, parentage analysis revealed lower estimates of self‐recruitment in the semi‐closed bay (0%) than in the open coast (14–15%). The result was consistent with dispersal simulations predicting lower LR and self‐recruitment in the semi‐closed bay (0.4% and 19%) compared to the open coast (2.9% and 38%). Dispersal modeling also showed that cross‐shore currents toward offshore were much stronger around the semi‐closed bay and were negatively correlated with LR and self‐recruitment. These results suggest that stronger cross‐shore currents around the semi‐closed bay transport anemonefish larvae to the offshore and mainly contributed to the lower self‐recruitment. Our results highlight importance of hydrodynamics on larval dispersal and difficulty in predicting self‐recruitment from coastline type alone. [ABSTRACT FROM AUTHOR]

For endemic benthos inhabiting hydrothermal vent fields, larval recruitment is critical for population maintenance and colonization via migration among separated sites. The vent‐endemic limpet, Lepetodrilus nux, is abundant at deep‐sea hydrothermal vents in the Okinawa Trough, a back‐arc basin in the northwestern Pacific; nonetheless, it is endangered due to deep‐sea mining. This species is associated with many other vent species and is an important successor in these vent ecosystems. However, limpet genetic diversity and connectivity among local populations have not yet been examined. We conducted a population genetics study of L. nux at five hydrothermal vent fields (maximum geographic distance, ~545 km; depths ~700 m to ~1650 m) using 14 polymorphic microsatellite loci previously developed. Genetic diversity has been maintained among these populations. Meanwhile, fine population genetic structure was detected between distant populations, even within this back‐arc basin, reflecting geographic distances between vent fields. There was a significant, positive correlation between genetic differentiation and geographic distance, but no correlation with depth. Contrary to dispersal patterns predicted by an ocean circulation model, genetic migration is not necessarily unidirectional, based on relative migration rates. While ocean circulation contributes to dispersal of L. nux among vent fields in the Okinawa Trough, genetic connectivity may be maintained by complex, bidirectional dispersal processes over multiple generations. [ABSTRACT FROM AUTHOR]

In this era of global climate change, understanding fundamental mechanisms of coral community maintenance and persistence in temperate non-reefal areas is a high marine conservation priority. To identify mechanisms of community maintenance and persistence via larval supply, we monitored coral settlement over 12 years and investigated the genetic population structure of two major acroporid species at Kushimoto, Wakayama Prefecture, Japan (33°N). Between 8 and 30 artificial settlement panel pairs were deployed from May or June to September, October, or November of each year. Recruits on settlement panel pairs were scarce, especially those of acroporids (0 or < 1 recruit per panel pair in most years). As coral cover in the Kushimoto area remained relatively high over a decade, such low recruitment may be sufficient for persistence of acroporid communities in this region. In addition, genetic analysis using 8 or 10 microsatellite markers demonstrated differences in genetic structure between populations of Acropora hyacinthus, which is a long-term resident species in this area, and A. muricata, a recently arrived species. Acropora hyacinthus displayed higher numbers of multilocus genotypes (41 of 43 samples collected) whereas only one multilocus genotype in 30 samples was seen in A. muricata. This difference may reflect both the length of time since population establishment and morphology. Consequently, acroporid communities in the Kushimoto area are likely maintained by survival and growth of existing colonies and/or fragmentation, indicating that conservation of established corals should be the first priority to ensure persistence of coral assemblages in such temperate non-reefal areas., Author(s): Masako Nakamura [sup.1] , Keiichi Nomura [sup.2] , Isao Hirabayashi [sup.2] , Yuichi Nakajima [sup.3] , Takumi Nakajima [sup.4] , Satoshi Mitarai [sup.3] , Hiroyuki Yokochi [sup.1] Author Affiliations: [...]

Exosomes are the master transporters of genes, RNAs, microRNAs, proteins, and lipids. They have applications in major diseases, including cancer, cardiovascular diseases, neurological disorders, and diabetes mellitus. Delivery of the exosomes to recipient cells is governed by the functional heterogenicity of the tissues. Engineered exosomes are promising tools in tissue regeneration. In addition to their role as intracellular communication cargos, exosomes are increasingly primed as standard biomarkers in the progression of diseases, thereby solving the diagnostic dilemma. Futuristic empowerment of exosomes with OMICS strategy can undoubtedly be a bio-tool in translational medicine. This review discusses the advent transformation of exosomes in regenerative medicine and limitations that are caveats to broader applications in clinical use.