Ultrastructure of thyroid C cells in sheep treated with vitamin D3.

Ultrastructural observation was performed in C cells of sheep injected intramuscularly with a dose of 2 million IU of vitamin D3 daily for 10 days, 20 days and 30 days, respectively. After treatment with vitamin D3, hyperplasia and hypertrophy of C cells were noticed mainly at the periphery of the thyroid follicles. Most of hypertrophied C cells degranulated conspicuously and contained many prosecretory granules near the well developed Golgi apparatus which were in the actively secreting and packaging phase of their secretory cycle. The other C cells had prominent lamellar arrays of rough-endoplasmic reticulum and aggregations of free ribosomes in the cytoplasm which were interpreted to be in the actively synthesizing phase of their secretory cycle. Atrophic C cells which contained degenerative organelles in the cytoplasm were occasionally observed among the hypertrophied C cells. The present ultrastructural findings clarified that C cells synthesize and secrete calcitonin continuously due to prolonged hypercalcemia induced by long-term administration of excessive doses of vitamin D3 in sheep.     

Optimal periods of night‐time lighting in the sea cage culture of Pacific bluefin tuna,Thunnus orientalis,juvenile (Temminck and Schlegel)

We have previously reported that night‐time lighting prevents the mass death of Pacific bluefin tuna (PBT) juvenile due to collision and/or contact with the walls of sea cages, immediately after transfer to the cages, and that night‐time lighting does not negatively impact fish stress levels. However, the period of night‐time lighting should be limited to minimize negative impacts on the surrounding environment and aid management. Therefore, we investigated the optimal period of night‐time lighting by evaluating the whole‐body cortisol and glucose levels as stress parameters, growth performance and survival of PBT juvenile in four cages with different periods of night‐time lighting (i.e. unlit, 4‐day, 8‐day and 12‐day lighting). The results showed that almost all fish were died 1 day after transfer to the unlit cage. In comparison, the other groups (4‐day, 8‐day and 12‐day lighting) had high survival rates (92.5–96.0%) without significant difference. However, in the 4‐day‐lighting group, an obvious stress response was recorded on day 5, and growth performance was significantly lower. In the 8‐day‐lighting group, whole‐body cortisol levels were slightly elevated on day 9; however, significantly elevation was not recorded on day 12. These results indicate that the recommended lighting period of night‐time lighting in sea cages is 8–12 days.     

Screening of Dried Plant Seed Extracts for Adiponectin Production Activity and Tumor Necrosis Factor-Alpha Inhibitory Activity on 3T3-L1 Adipocytes

To search for dried plant seeds with potent anti-diabetes activity, we conducted a large scale screening for inhibitory activity on tumor necrosis factor-alpha and facilitating activity on adiponectin production in vitro. These activities in 3T3-L1 adipocytes were screened from ethanol extracts of 20 kinds of dried plant seed marketed in Japan. komatsuna (Brassica rapa var. perviridis), common bean (Phaseolus vulgaris L.), qing geng cai (Brassica rapa var. chinensis), green soybean (Glycine max), spinach (Spinacia oleracea L.) and sugar snap pea (Pisum sativum L.) markedly enhanced adiponectin production (11.3 ~ 12.7 ng/ml) but Japanese radish (Raphanus sativus), edible burdock (Arctium lappa L.), bitter melon (Momordica charantia) and broccoli (Brassica oleracea var. italica) did not (0.9 ~ 2.7 ng/ml). All adiponectin-production-enhancing seeds except spinach (2.7 pg/ml) and okra (Abelmoschus esculentus) (6.6 pg/ml) effectively decreased tumor necrosis factor-alpha levels (0.0 pg/ml). We further examined the effects on free radical scavenging activities in the dried seed extracts. Although scavenging activity correlated well with total phenolic content of samples, no correlation was observed with adiponectin production. These results point to the potential of dried seed extracts as a means to modify the activity of tumor necrosis factor-alpha for the adiponectin production.     

Persistence of fish populations in the upper Paraná River: effects of water regulation by dams

Abstract –  River–floodplain systems present intense temporal variations in physical, chemical and biological factors. These variations are closely related to alterations in water levels, which have been attributed to the flood pulse. As several species are strictly related to the flood pulse to fulfil their life cycle, the pulse may be seen as a dispersal mechanism of species onto a floodplain. In this study, we determine how dam construction influenced the persistence of Prochilodus lineatus population, a large migratory fish species from the upper Paraná River floodplain. Data used were collected in two distinct periods, from April 1992 to March 1993 and from January 1999 to December 2001. Fish were collected using seining nets in six (monthly in the first period) and seven (quarterly in the second period) isolated lagoons. The fraction of occupied lagoons was high in the first period (higher than 0.65), when flood was intense. However, in the second period, when the flood pulse did not happen or was short, the fraction of occupied lagoons sharply decreased over time (from 0.85 to 0.22). For the first period, no model fitted to data, but for the second period, a negative linear model (named drought-dependent model) presented good fit ( r ² = 0.97). Therefore, it is possible to infer that long and intense flood pulses are important to maintain the persistence of P. lineatus populations in the floodplain. The artificial control of water levels prompted by dams disrupts this dynamic, reducing persistence to critical levels.     

Uterine NK cells produce epidermal growth factor in the murine pregnant uterus.

Uterine natural killer (uNK) cells belong to the large granular lymphocytes in the murine pregnant uterus and play essential roles in pregnancy success. We defined whether uNK cells can produce epidermal growth factor (EGF) important for implantation and embryo growth. The uNK cells were immunohistochemically positive for anti-EGF antibody especially during days 6 to 9 and at day 15 of pregnancy. Immunoreaction for EGF receptor was observed on the stromal cells in the metrial gland and trophoblasts in the placental labyrinth. EGF secretion (72.1 +/- 2.25 ng/10(40 cells) was noted in cultured uNK cells isolated from the metrial gland at day 15 of pregnancy. Treatment of anti-asialo-GM I antibody raised the level of EGF (129 +/- 21.5 ng/10(4) cells). These results suggest uNK cell can produce and release EGF for placental development.     

Effect of vitamin B2 on somatic cell counts in milk of clinical Staphylococcus aureus mastitis.

Effects of intravenous injection of Vitamin B2 (VB2) on the nitroblue tetrazolium (NBT) reductivity of peripheral blood neutrophils and the somatic cell counts (SCC) in quarter milk of Staphylococcus aureus mastitis were investigated. The NBT reductivities of neutrophils were enhanced at 2 days after single injection of VB2 (5.0 and 2.5 mg/kg), and were also enhanced at 4 days after initial injection of continuous 3 days of VB2 (2.5 mg/kg). The SCC in quarter milk were significantly decreased at 3, 7 and 14 days after initial injection of continuous 3 days of VB2 (2.5 mg/kg), however, S. aureus in the infected quarter was not cured bacteriologically by VB2 injection.     

Comparison of extractive components in muscle and liver of three Loliginidae squids with those of one Ommastrephidae species

Extractive components were determined for the mantle muscle and liver of three species of Loliginidae squid, Sepioteuthis lessoniana, Loligo bleekeri, and L. edulis, and one species of Ommastrephidae, Todarodes pacificus, as a control. Total free amino acid levels and the major free amino acids in muscle, taurine, proline, glycine, alanine, and arginine, were significantly higher in Loliginidae squids than in T. pacificus. The main nucleotide was adenosine 5′-monophosphate, which did not differ significantly between species. Malate was the organic acid found in muscle in highest concentrations. The muscle of these species contained a large amount of trimethylamine oxide. A large amount of glycine betaine was also detected in the muscle, but showed no large species difference. From these results, the muscle of Loliginidae species is considered to have a much sweeter taste than that of T. pacificus. Compared with muscle, squid liver was characteristic with high contents of taurine, glutamate, bitter amino acids, succinate, propionate, trimethylamine, and glycine betaine, and with low contents of sweet amino acids, arginine, nucleotides, malate, and trimethylamine oxide. These results suggest that squid liver is characterized by a complicated taste containing umami, bitterness, sourness, fishy flavor, and less sweetness.