Mudskipper genomes provide insights into the terrestrial adaptation of amphibious fishes

Mudskippers are amphibious fishes that have developed morphological and physiological adaptations to match their unique lifestyles. Here we perform whole-genome sequencing of four representative mudskippers to elucidate the molecular mechanisms underlying these adaptations. We discover an expansion of innate immune system genes in the mudskippers that may provide defence against terrestrial pathogens. Several genes of the ammonia excretion pathway in the gills have experienced positive selection, suggesting their important roles in mudskippers’ tolerance to environmental ammonia. Some vision-related genes are differentially lost or mutated, illustrating genomic changes associated with aerial vision. Transcriptomic analyses of mudskippers exposed to air highlight regulatory pathways that are up- or down-regulated in response to hypoxia. The present study provides a valuable resource for understanding the molecular mechanisms underlying water-to-land transition of vertebrates

Examining the Optimization of Urban Design -- Analysis of Urbanization-Related Tactics for Enhancing Livable Street Spaces

In the context of rapid urbanization, the detailed planning of urban design lacks an integrated consideration of old and new spaces and humanized design, revealing a number of aspects that need to be improved. The living street environment, which is most intimately connected to people’s daily activities, typically lacks convenience and comfort, a humanized design, street dynamics, and a natural and humanistic appearance. In order to better understand the direction of improving the living street space in the context of urbanization, this paper discusses the research background, the concepts related to street space, analyzes the research methods, specific cases, and current problems, and through the literature research and quantitative research, puts forward ideas on the optimization strategies of living street space, and attempts to summarize the generally applicable direction of street space optimization

Cardiac performance of Chinese black sleeper (Bostrichthys sinensis) at early stages of development under hypoxic conditions

Cardiac performance of the Chinese black sleeper (Bostrichthys sinensis) was examined at early stages of development (the heartbeat, blood circulation and newly hatched larval stages) under different hypoxic oxygen concentrations. Exposure of the embryos at 25 degrees C to 0.2 mg/l dissolved oxygen (DO) indicated periodic heartbeat at both the heartbeat stage and the blood circulation stage, but it started sooner after exposure at the blood circulation stage than at the heartbeat stage. With the appearance of the gill slits, the tolerance of the newly hatched larvae to hypoxia was improved. The larvae did not display periodic heartbeat at 0.2 mg/L DO, but periodic heartbeat occurred at 0.1 mg/L DO and 0.02 mg/L DO after 23.3 +/- 6.2 minutes and 13.2 +/- 3.4 minutes of exposure. With exposure of the embryos to hypoxia, the occurrence of periodic heartbeat of excised embryos was earlier than that of whole egg embryos at both the blood circulation and heartbeat stages. These results indicated that the tolerance of embryos to hypoxia decreased with the progress of embryogenesis and suggested that the perivitelline liquid can protect the embryos by conserving oxygen. In this study, we also found that a breakdance performance (an arrhythmic heart beat) occurred in the newly hatched larvae at 0.02 mg/l DO. The breakdance performance lasted about 10 minutes, and then the heartbeat became normal.National Natural Science Foundation of China [40476056

Hypoxic tolerance of Chinese black sleeper Bostrichthys sinensis embryos at heartbeat stage

Tolerance of hypoxia in Chinese black sleeper (Bostrichtlyssinensis) embryos at heartbeat stage was examined at different oxygen concentrations. Embryonic response to hypoxic conditions was expressed in terms of the intensity, of variation in heartbeat rate (17). Exposure of the embryos at 25 degrees C to 0.5, 1.0 and 1.5 mg/l dissolved oxygen (DO), caused bradycardia, which was developed within the first 10 mill of hypoxia, followed by a plateau, and lasted until termination of the hypoxia. The V values were significantly affected by DO concentrations (P 0.05)

Rates of oxygen consumption and tolerance of hypoxia and desiccation in Chinese black sleeper (Bostrichthys sinensis) and mudskipper (Boleophthalmus pectinirostris) embryos

The rates of oxygen consumption, tolerance of hypoxia and desiccation of the Chinese black sleeper (Bostrichthys sinensis) and mudskipper (Boleophthalmus pectinirostris) embryos were investigated. The pattern of oxygen consumption of the Chinese black sleeper embryos was similar to that of the mudskipper ones. The lowest rates of oxygen consumption [(1.65 +/- 0.66) nmol/(ind. center dot h)] of the Chinese black sleeper embryos 16 h after fertilization and the lowest rates of oxygen consumption [(0.79 +/- 0.08) nmol/(ind. center dot h)] of the mudskipper embryos 6 h after fertilization were recorded, respectively. Then the rates of oxygen consumption of these two species embryos increased gradually until hatching [8.26 +/- 1.70) nmol/(ind. center dot h) in the Chinese black sleeper, (2.69 +/- 0.23) nmol/(ind. center dot h) in mudskipper]. After exposure to hypoxia water (0.16 mg/dm(3)), bradycardia of the embryos occurred in both the Chinese black sleeper and the mudskipper. However, the Chinese black sleeper embryos survived approximately 45 min longer than the mudskipper ones. After exposure to desiccation at a relative humidity of 58%, bradycardia of the embryos was observed in both the Chinese black sleeper and the mudskipper, and the Chinese black sleeper embryos lived approximately 9 min longer than the mudskipper ones

Immune Response of Turbot to Polyriboinosinic-polyribocytidilic Acid: the Transcription of Mx, Hepcidin, and IgM

Polyriboinosinic-polyribocytidilic acid (poly I:C) was administered to turbot, Scophthalmus maximus, via injection, oral route, and immersion. Samples of liver, spleen, and head kidney were individually collected at different time intervals (0, 24, 48, 72, 96, and 120 h) after poly I:C treatments. Transcription levels of Mx, hepcidin, and IgM in the organs of turbot were detected using RT-PCR. It was found that Mx mRNA was significantly induced in the liver, head kidney, and spleen 48-h postinjection with poly I:C, and the effects of immersion and oral route on Mx transcription were analogous to that of injection method. Meanwhile, the hepcidin mRNA was significantly induced in the spleen but not in the liver and head kidney 48-h postinjection. No significant increase of IgM mRNA was found in the liver and spleen after poly I:C challenge. The results indicated that the antivirus state resulted from the Mx expression and could be induced with poly I:C via injection, immersion, and oral methods. The influence of poly I:C on IgM and hepcidin transcription suggested that both innate and adaptive immunity could be modulated through interferon-inducible signaling pathways.Emarked Fund for Modern Agro-industry Technology Research System [nycytx-50]; Qingdao Key Laboratory for Marine Fish Breeding and Biolog