Determination of maturity in male hawksbill turtle <Emphasis Type="Italic">Eretmochelys imbricata</Emphasis> in captivity based on tail elongation and plasma testosterone level

To determine the sexual maturity of fourteen male wild-caught hawksbill turtles [straight carapace length (SCL) range 63–79 cm] held in captivity, we investigated their hormone levels in blood and morphological characteristics. Male turtles were divided into two groups: five individuals showing mating behavior (group A) and nine individuals not showing mating behavior (group B). Then, seasonal changes of plasma testosterone of both groups were studied. We also tried to determine male maturity based on tail elongation (TE) index, i.e., the ratio of tail length (TL) to SCL. Plasma testosterone level of group A gradually increased during premating and then sharply declined to low levels between mating and postmating seasons. In contrast, that of group B remained low during the experimental periods. The distinct seasonal changes of plasma testosterone levels of groups A and B correlated with their maturity. Furthermore, males were clearly divided into mature and immature based on TE values >0.35 and <0.33, respectively, corresponding to results based on plasma testosterone levels. Our results indicate that TE can be used more conveniently and accurately to determine maturity of male hawksbill turtles in captivity.     

Characteristics of a self-assembled fibrillar gel prepared from red stingray collagen

A translucent collagen gel was formed from a transparent acidic solution of red stingray collagen by adjusting to physiological ionic strength and pH in phosphate buffer and then incubating at 25–37°C. During fibril formation from red stingray collagen, the turbidity increased when the NaCl concentration was increased at constant pH and the rate of fibril formation was accelerated by higher pH or lower NaCl concentration. The T _m of red stingray collagen fibrillar gel was estimated as 44.3 ± 3.5°C, which was higher than that of the collagen solution, 33.2°C. In addition, red stingray collagen gel maintained its shape without melting and was suitable for culture of mouse stromal cells at 37°C.     

DNA polymorphism in the chicken growth hormone gene: Association with egg production

Restriction fragment length polymorphic markers in the chicken growth hormone (GH) gene were tested for their association with egg production traits. Alleles of GH were determined in 3 non‐inbred strains from different genetic bases. The frequency of PS1 (+) allele in the three strains was very low in contrast to the layer strain previously reported. Results of the present study indicate that the frequency of PS (+) is related to egg production and that the PS1 (+) allele may be used as a genetic marker for selection in egg production.     

Molecular cloning of two types of spiggin cDNA in the three-spined stickleback, Gasterosteus aculeatus

Two types of spiggin cDNAs were isolated from the three-spined stickleback. Northern blot analysis revealed that glue protein is composed of multiple spiggin molecules, and that their synthesis in kidney is strongly up-regulated by androgens.     

Cytotoxic constituents in the holdfast of cultivated Laminaria japonica

ABSTRACT:     Four steroidal ketones were isolated from the holdfast of cultivated Laminaria japonica . The structures were characterized as ergosta-4,24(28)-diene-3-one (1), ergosta-4,24(28)-diene-3,6-dione (2), stigmasta-4,24(28)-diene-3-one (3) and stigmasta-4,24(28)-diene-3,6-dione (4), by spectral data. Compounds 2 and 4 were shown to be cytotoxic against the MCF-7 human breast cancer cell, and the growth of MCF-7 was inhibited by 96% and 79%, respectively, at 10 µg/mL. It is the first report on the isolation of cytotoxic steroidal ketones from the kelp in the genus of Laminaria.     

Response changes with growth in the gustatory receptors of young yellowtails (Seriola quinqueradiata)

SUMMARY: Laboratory-hatched juvenile yellowtails (mean fork length, 9.3 cm) were reared for 2 months in two groups on different kinds of food, mysid and squid in one group and fish in the other, and the gustatory neural responses to seven chemicals (adenosine-5'-monophosphate, alanine, arginine, betaine, proline, tryptophan, and valine) were recorded in fish before and after the 2-month rearing period. Large variances in the responses to some chemicals were noticed in the juveniles before the rearing experiment. Mann–Whitney U -tests on the neural responses indicated significant changes in the magnitude of the responses to valine and some other chemicals relative to that for proline or tryptophan between the pre- and the two post-rearing groups. No significant differences in the response magnitude for the seven chemicals were observed for the two post-rearing groups suggesting that the response changes during the 2-month rearing might have been intrinsic and not due to specific food items in the diet. The dose–response relationship for some chemicals was also examined in the juveniles before and after the 2-month rearing. A slight lowering of threshold was noticed for alanine and valine after the rearing. Data on the responses of wild yellowtails were in support of the changing responsiveness of gustatory receptors during development of juvenile yellowtails.     

Correction to: Precocious maturation in male tiger pufferfish Takifugu rubripes: genetics and endocrinology

Fisheries Science - A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01505-w     

The original papers appeared in the Journal of Japanese Forestry Society vol. 86, no. 3 in Japanese with English abstracts

Abstracts from the Journal of Japanese Forestry Society

The original papers appeared in the Journal of Japanese Forestry Society vol. 86, no. 3 in Japanese with English abstracts     

alpha-Glucosidase inhibitory profile of catechins and theaflavins

To clarify the postprandial glucose suppression effect of flavonoids, the inhibitory effects of catechins and theaflavins against alpha-glucosidase (AGH) were examined in this study. It was initially demonstrated that theaflavins and catechins preferentially inhibited maltase rather than sucrase in an immobilized AGH inhibitory assay system. For the maltase inhibitory effects of theaflavins, the effects were observed in descending order of potency of theaflavin (TF)-3-O-gallate (Gal) > TF-3,3'-di-O-Gal > TF-3'-O-Gal > TF. This suggests that the AGH inhibition induced by theaflavins is closely associated with the presence of a free hydroxyl group at the 3'-position of TF as well as the esterification of TF with a mono-Gal group. In addition, the R-configuration at the 3'-position of TF-3-O-Gal showed a higher inhibitory activity than the S-configuration. As a result of a single oral administration of maltose (2 g/kg) in rats, a significant reduction in blood glucose level was observed at a dose of 10 mg/kg of TF-3-O-Gal, demonstrating for the first time that TF-3-O-Gal can suppress glucose production from maltose through inhibition of AGH in the gut.     

Pericardial mesothelioma in a neonatal calf

We encountered an extremely rare tumor, a pericardial mesothelioma, in a neonatal calf. The patient calf showed severe abdominal distention, and died immediately after birth. The thoracic cavity was contained a huge heart with a large amount of pericardial fluid. A number of granular and cobblestone-like nodules were dispersed over the epicardium and pericardium. The nodules consisted of papillary proliferations of neoplastic cells, and the neoplasm occasionally showed mesenchymal proliferations. Immunohistochemistry revealed that they had the characteristics of mesothelial cells (cytokeratin-and vimentin-positive), and the neoplasm was diagnosed as mesothelioma.