China is on the track tackling Enteromorpha spp forming green tide

Green tide management is supposed to be a long term fight rather than an episode during the 29th Olympic Games for China, since it has been gaining in scale and frequency during the past 3 decades in both marine and estuary environment all over the world. A number of rapid-responding studies including oceanographic comprehensive surveys along the coastline have been conducted during the bloom and post-bloom periods in 2008 by Chinese marine scientists. The preliminary results are as below: (1) phylogenetic analysis indicates that the bloom forming alga forms a clade with representatives of the green seaweed Enteromorpha linza, though, the alga has been identified as E. proliera by means of morphological; (2) the present data suggest that the bloom was originated from south of Yellow Sea, but not the severely affected area near Qingdao City; (3) pathways of reproduction for E. prolifera have approved to be multifarious, including sexual, asexual and vegetative propagation; (4) somatic cells may act as a propagule bank, which is supposed to be a very dangerous transmitting way for its marked movability, adaptability and viability; (5) pyrolysis of the alga showed that three stages appeared during the process, which are dehydration (18–20^o^C), main devolatilization (200–450^o^C) and residual decomposition (450–750^o^C), and activation energy of the alga was determined at 237.23 KJ•mol^-1^. Although the scarce knowlegde on E. prolifera not yet allow a fully understanding of the green tide, some of the results suggests possible directions in further green tide research and management

Population genetic structure and demographic history of small yellow croaker, Larimichthys polyactis (Bleeker, 1877), from coastal waters of China

Small yellow croaker, Larimichthys polyactis (Bleeker, 1877), a commercially important benthopelagic fish, is widely distributed in the Bohai, Yellow and East China Seas. To evaluate the population genetic structure and demographic history of L. polyactis, we sequenced the complete mitochondrial deoxyribonucleic acid (mtDNA) control region (798 to 801 bp) in 127 individuals sampled from seven localities throughout its distribution region in China. A total of 136 polymorphic sites were detected, which defined 125 haplotypes. High haplotype diversity (1.000 ± 0.013 to 1.000 ± 0.034) and moderate nucleotide diversity (0.0112 ± 0.0061 to 0.0141 ± 0.0075) were detected in the species. The neighbor-joining tree of haplotypes was assigned into two closely related clades, but did not appear to have any geographic genealogic structure. Hierarchical molecular variance analysis (AMOVA), pair wise FST comparisons and the nearest-neighbor statistic (Snn) showed no significant genetic differences among populations in the Bohai, Yellow and East China Seas. The demographic history of L. polyactis was examined by using neutrality tests and mismatch distribution analysis, which revealed that the species had undergone a Pleistocene population expansion. The results based on the complete mtDNA control region sequences analysis indicate that within its distribution range, L. polyactis constituted a panmictic mtDNA gene pool. Factors such as dispersal capacity, ocean currents and insufficient evolution time could be responsible for the lack of population genetic differentiation in L. polyactis.Keywords: Larimichthys polyactis, mitochondrial control region, population genetic structure, demographi

Isolation and Characterization of New 24 Microsatellite DNA Markers for Golden Cuttlefish (Sepia esculenta)

Twenty-four microsatellite DNA markers were isolated and characterized for golden cuttlefish (Sepia esculenta) from a (GT)13—enriched genomic library. Loci were tested in 48 individuals from Jiaozhou bay of China. The numbers of alleles per locus ranged from two to 25 with an average of 10.3. The observed and expected heterozygosities ranged from 0.063 to 0.896 and from 0.137 to 0.953, with averages of 0.519 and 0.633, respectively. Six loci significantly deviated from Hardy-Weinberg equilibrium after Bonferroni’s correction and no significant linkage disequilibrium between loci pairs was detected. These microsatellite markers would be useful for analyzing the population genetic structure to make conservation and management decisions for S. esculenta

Mitochondrial Homeostasis Regulating Mitochondrial Number and Morphology Is a Distinguishing Feature of Skeletal Muscle Fiber Types in Marine Teleosts

Fishes’ skeletal muscles are crucial for swimming and are differentiated into slow-twitch muscles (SM) and fast-twitch muscles (FM) based on physiological and metabolic properties. Consequently, mitochondrial characteristics (number and morphology) adapt to each fiber type’s specific functional needs. However, the mechanisms governing mitochondrial adaptation to the specific bioenergetic requirements of each fiber type in teleosts remain unclear. To address this knowledge gap, we investigated the mitochondrial differences and mitochondrial homeostasis status (including biogenesis, autophagy, fission, and fusion) between SM and FM in teleosts using Takifugu rubripes as a representative model. Our findings reveal that SM mitochondria are more numerous and larger compared to FM. To adapt to the increased mitochondrial number and size, SM exhibit elevated mitochondrial biogenesis and dynamics (fission/fusion), yet show no differences in mitochondrial autophagy. Our study provides insights into the adaptive mechanisms shaping mitochondrial characteristics in teleost muscles. The abundance and elongation of mitochondria in SM are maintained through elevated mitochondrial biogenesis, fusion, and fission, suggesting an adaptive response to fulfill the bioenergetic demands of SM that rely extensively on OXPHOS in teleosts. Our findings enhance our understanding of mitochondrial adaptations in diverse muscle types among teleosts and shed light on the evolutionary strategies of bioenergetics in fishes