Inference of potential genetic risks associated with large-scale releases of red sea bream in Kanagawa prefecture, Japan based on nuclear and mitochondrial DNA analysis

Since 1978, millions of hatchery-reared red sea bream (Pagrus major) juveniles have been released in Sagami Bay and Tokyo Bay in Kanagawa Prefecture, Japan. The stock enhancement program has contributed to total catch; however, no information regarding the genetic interactions with wild counterparts is available. Here, we combined 15 microsatellite loci and mitochondrial D-loop sequencing to characterize the genetic resources of red sea bream in Sagami Bay and Tokyo Bay and to elucidate the potential harmful genetic effects associated with fish releases. Both types of markers evidenced higher levels of genetic diversity in wild samples (SB and TB) compared with offspring before stocking (H07 and H08) as well as a hatchery-released sample recaptured in Sagami Bay (HR). Microsatellite F (ST) estimates and Bayesian clustering analysis found significant genetic differences among samples (F (ST) = 0.013-0.054), except for the two wild samples (F (ST) = 0.002) and HR vs. H07 (F (ST) = 0.007). On the other hand, mitochondrial-based Dcurrency sign (ST) suggested haplotypic similarity between SB, H07, and HR. The low effective number of females contributing to the offspring over multiple generations may be responsible for the lack of haplotypic differentiation. Moreover, the putative hatchery origin to three fish (8 %) without deformity in the inter-nostril epidermis was inferred for the first time. Our results showed the usefulness of combining nuclear and mitochondrial markers to elucidate genetic interactions between hatchery-released and wild red sea bream and warned about potential harmful genetic effects should interbreeding takes place

Comparison of behavioural development between Japanese flounder (Paralichthys olivaceus) and spotted halibut (Verasper variegatus) during early life stages

Behavioural development was compared between two flatfish species (Japanese flounder and spotted halibut) from hatching to settlement (juvenile stage) in order to speculate on the ecology of their early life stages and to provide fundamental knowledge for improving seedling production techniques for stock enhancement. Fish were cultured under identical rearing conditions (500-L tank maintained at 17.8 ± 0.4°C, 34 ppt, 10L : 14D light regime and an initial stocking density of 20 larvae L－1). Behavioural observations were conducted at about 4-day intervals from hatching to the juvenile stage. Fish were sampled randomly from the rearing tank, and one fish was transferred into a 250-ml observation container. Behaviour was video-recorded for 5 min without food and for an additional 5 min with live feed (rotifer or Artemia). All behavioural data were sorted according to eight developmental stages and compared among developmental stages and between species. The average standard length of the spotted halibut was significantly greater than that of the Japanese flounder in all developmental stages, while the development of Japanese flounder was faster than that of the spotted halibut. For Japanese flounder, feeding, swimming and Ohm-posture (typical shivering behaviour observed during early life stages in flatfishes) frequency were highest before metamorphosis (mean ± SD; 1.0 ± 2.0 attacks min－1, 24.0 ± 9.6 actions min－1, 1.1 ± 1.1 counts min－1, respectively). Spotted halibut expressed feeding behaviour frequently from the beginning of metamorphosis (3.6 ± 5.2 attacks min－1), had relatively low swimming activity during all developmental stages, and showed a peak of Ohm-posture frequency during the flexion stage (2.6 ± 1.0 counts min－1).The definitive version is available at www.blackwell-synergy.co

Serum Kisspeptin Levels in Korean Girls with Central Precocious Puberty

Central precocious puberty (CPP) is caused by premature activation of hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Kisspeptin and G-protein coupled receptor-54 system is the essential gatekeeper of the reproductive system, playing a key role in the activation of the gonadotropic axis at puberty. We aimed to determine whether serum kisspeptin may function as a marker for CPP by investigating serum kisspeptin levels in Korean girls with CPP and their prepubertal controls. Serum kisspeptin levels of Korean girls with CPP (n = 30) and age-matched healthy prepubertal controls (n = 30) were measured with a competitive enzyme immunoassay. Serum kisspeptin levels were significantly higher in CPP group than in control group (4.61 ± 1.78 vs 2.15 ± 1.52 pM/L, P < 0.001). Serum kisspeptin was positively correlated with peak luteinizing hormone (LH), peak/basal LH ratio and peak LH/follicular-stimulating hormone (FSH) ratio during GnRH stimulation test. CPP is supposed to be triggered by premature increase of kisspeptin. Serum kisspeptin may be used as a marker of CPP. Further studies on KISS1 gene polymorphisms leading to higher risk of premature increase of kisspeptin and upstream regulator of kisspeptin are also needed

Transcriptional profiling of Epstein–Barr virus (EBV) genes and host cellular genes in nasal NK/T-cell lymphoma and chronic active EBV infection

Nasal NK/T-cell lymphoma is an aggressive subtype of non-Hodgkin lymphoma (NHL) that is closely associated with Epstein–Barr virus (EBV). The clonal expansion of EBV-infected NK or T cells is also seen in patients with chronic active EBV (CAEBV) infection, suggesting that two diseases might share a partially similar mechanism by which EBV affects host cellular gene expression. To understand the pathogenesis of EBV-associated NK/T-cell lymphoproliferative disorders (LPD) and design new therapies, we employed a novel EBV DNA microarray to compare patterns of EBV expression in six cell lines established from EBV-associated NK/T-cell LPD. We found that expression of BZLF1, which encodes the immediate-early gene product Zta, was expressed in SNK/T cells and the expression levels were preferentially high in cell lines from CAEBV infection. We also analyzsd the gene expression patterns of host cellular genes using a human oligonucleotide DNA microarray. We identified a subset of pathogenically and clinically relevant host cellular genes, including TNFRSF10D, CDK2, HSPCA, IL12A as a common molecular biological properties of EBV-associated NK/T-cell LPD and a subset of genes, such as PDCD4 as a putative contributor for disease progression. This study describes a novel approach from the aspects of viral and host gene expression, which could identify novel therapeutic targets in EBV-associated NK/T-cell LPD

Data from: Effects of large-scale releases on the genetic structure of red sea bream (Pagrus major, Temminck et Schlegel) populations in Japan

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Effects of large-scale releases on the genetic integrity of red sea bream (Pagrus major, Temminck et Schlegel)

Large-scale hatchery releases are carried out for many marine fish species worldwide; nevertheless, the long-term effects of this practice on the genetic structure of natural populations remains unclear. The lack of knowledge is especially evident when independent stock enhancement programs are conducted simultaneously on the same species at different geographical locations, as occurs with red sea bream (Pagrus major, Temminck et Schlegel) in Japan. In this study, we examined the putative effects of intensive offspring releases on the genetic structure of red sea bream populations along the Japanese archipelago by genotyping 848 fish at fifteen microsatellite loci. Our results suggests weak but consistent patterns of genetic divergence (FST = 0.002, p < 0.001). Red sea bream in Japan appeared spatially structured with several patches of distinct allelic composition, which corresponded to areas receiving an important influx of fish of hatchery origin, either released intentionally or from unintentional escapees from aquaculture operations. In addition to impacts upon local populations inhabiting semi-enclosed embayments, large-scale releases (either intentionally or from unintentional escapes) appeared also to have perturbed genetic structure in open areas. Hence, results of the present study suggest that independent large-scale marine stock enhancement programs conducted simultaneously on one species at different geographical locations may compromise native genetic structure and lead to patchy patterns in population genetic structure

Development of a culture protocol for Rhodomonas sp. Hf-1 strain through laboratory trials

Rhodomonas sp. Hf-1 is a marine microalgal strain with a high nutritional value. In order to produce this microalga effectively and inexpensively in a hatchery, its production protocol was reexamined through several culture trials. Firstly, it was found that the Hf-1 strain required nitrogen, phosphorus, iron, manganese and vitamin B-12. The optimal nitrogen source was urea. Based on these results, a new medium, MU-SW, was formulated from agricultural fertilizers. Secondly, MU-SW medium was verified at production scale, in which satisfactory growth of the Hf-1 strain was obtained. The cell density reached approximately 3.0x10(6)cellsml(-1), and five harvest cycles at 4-day intervals could be achieved. The high unsaturated fatty acid content of the harvested cells fluctuated in the following ranges: C18:2n-6, 19.8-25.2%; C18:3n-6, 8.7-15.2%; C20:4n-6, 2.0-4.6%; C20:5n-3, 8.2-11.3% and C22:6n-3, 5.6-7.3%. This study provides the baseline conditions for introducing the Hf-1 strain into an aquaculture food chain