Observation of three‐dimensional flow structures and effluent transport around fish cages using a towed ADCP and free‐fall multi‐parameter profiler

A field campaign was conducted around salmon cages, using a combination of a towed ADCP and a free‐fall multi‐parameter profiler, in order to investigate flow structures and the possible distribution of effluent materials. Two transect observations showed that hydrographic conditions changed dramatically within 5 days, from highly stratified open water conditions to weak stratification. Three‐dimensional observation revealed that flow was blocked behind the cages and that the blockage was reduced as the distance from the cages increased. The flow speed was positively correlated with the intensity of the backscattering signal. The R² value was high immediately behind the cages and decreased with distance from the cages. The flow time series behind the cages exhibited a k^–2 power law spectrum that was consistent with a typical internal wave spectrum. This suggests that eddies shed from the cages were highly influenced by stratification. We estimated the rate of kinetic energy dissipation, , from YODA Profiler data based on the Thorpe scale approach. We also estimated the eddy diffusivity coefficient, . Both and followed a lognormal probability density function. The mean was consistent with a one‐dimensional diffusion model assessed from the R² values of flow speed and backscatter intensity.     

Positional strategy of trunk muscles among aquatic,semi-aquatic and terrestrial species in Urodela

Clarification of the trunk structure in Urodela is important in understanding the locomotive evolution of basal tetrapods. The components of the muscular trunk wall among Urodela using different modes of locomotion were compared. Since the whole trunk may be used for swimming and the effect of limbs may be small in the more aquatic species, they showed smaller differences in the trunk muscles among anterior, middle and posterior sections of the trunk. By contrast, in the more terrestrial species, the dorsal and abdominal muscles are larger in the middle section than those in the anterior and posterior sections. High compressive stresses occur in the supporting limbs and their insertion at the trunk on the ventral side, and spread from the forelimbs along the back to the supporting hindlimbs on the dorsal side. Tensile stresses occur in the middle ventral part. The components of the trunk muscles among the three sections may reflect differences in stresses occurring in the trunk of the more terrestrial species. The findings also suggest that in the middle section, larger dorsal muscles for stiffening the back to maintain posture and larger abdominal muscles are responsible for balancing the body weight while it is supported by the limbs in the more terrestrial species.     

Effects of silvopastoral areas on milk production at dual-purpose cattle farms at the semi-humid old agricultural frontier in central Nicaragua

In extensive cattle production systems, the composition of grazing areas may significantly influence productivity. In dual-purpose cattle production systems in the lowland tropics, pasture lands with trees, so-called silvopastoral areas, are considered as being important, particularly to facilitate the management of crossbred European native cattle. The aim of the study was to quantify the effects of silvopastoral areas on production at dual-purpose cattle farms in the semi-humid lowlands of central Nicaragua. The relationships between seasonal milk production and herd data, and the proportions of land use types were examined for 74 farms by stepwise regression analysis.     

HIV-1 integrase and neuraminidase inhibitors from Alpinia zerumbet

AIDS and influenza are viral pandemics and remain one of the leading causes of human deaths worldwide. The increasing resistance of these diseases to synthetic drugs demands the search for novel compounds from plant-based sources. In this regard, the leaves and rhizomes of Alpinia zerumbet, a traditionally important economic plant in Okinawa, were investigated for activity against HIV-1 integrase (IN) and neuraminidase (NA). The aqueous extracts of leaves and rhizomes had IN inhibitory activity with IC(50) values of 30 and 188 μg/mL, whereas against NA they showed 50% inhibition at concentrations of 43 and 57 μg/mL, respectively. 5,6-Dehydrokawain (DK), dihydro-5,6-dehydrokawain (DDK), and 8(17),12-labdadiene-15,16-dial (labdadiene) were isolated from the rhizomes and were tested for enzyme inhibitions. DK and DDK strongly inhibited IN with IC(50) of 4.4 and 3.6 μg/mL, respectively. Against NA, DK, DDK, and labdadiene exhibited mixed type of inhibition with respective IC(50) values of 25.5, 24.6, and 36.6 μM and K(i) values ranging from 0.3 to 2.8 μM. It was found that DDK is a slow and time-dependent reversible inhibitor of NA, probably with a methoxy group as its functionally active site. These results suggest that alpinia could be used as a source of bioactive compounds against IN and NA and that DK and DDK may have possibilities in the design of drugs against these viral diseases.     

Regulation of muscular glutamate metabolism by high‐protein diet in broiler chicks

The major taste active component, glutamate (Glu), improves the taste of meat. In this study, we investigated the effect of a short‐term high‐protein (HCP) diet on the intramuscular free Glu content to improve the taste of meat. Furthermore, we elucidated how the muscle free Glu content was controlled by the HCP diet. Chicks (14 days old) were fed the control diet or HCP diet for 10 days. Plasma and muscle free amino acid concentrations, and activity and messenger RNA (mRNA) expression of muscle enzymes related to Glu metabolism were determined. Muscle free Glu content was increased (P < 0.01) by 51%. Activity and mRNA expression of glutaminase (GA), which is one of the major Glu‐related enzymes, were significantly decreased (P < 0.05) in the HCP group because of feedback inhibition. The mRNA expression of lysine α‐ketoglutarate reductase (LKR), which is the enzyme involved in lysine (Lys) degradation and Glu production, was significantly increased (P < 0.001) in the HCP group. These results suggest that short‐term dietary HCP feeding is an effective treatment for improving the taste of meat. Furthermore, our results suggest that the free Glu content in muscle is regulated by GA and LKR.     

Post-molt processes of cuticle formation and calcification in the Japanese mitten crab <Emphasis Type="Italic">Eriocheir japonicus</Emphasis>

This study examines the following in the Japanese mitten crab: (1) the structure of the exoskeleton with special reference to its calcification; (2) the progression of post-molt cuticle formation and calcification. In the crab, the structure and calcification state of the exoskeleton at the molt and during the inter-molt stage were similar to those of other crustaceans. During the inter-molt, the exoskeleton consisted of four cuticle layers; the outermost epicuticle, the exocuticle, the endocuticle and the innermost membrane layer. Intense calcification was observed in the exo- and endocuticle. At the molt, the synthesis of the epi- and exocuticle was already complete, and the addition of the endocuticle began after the molt. Calcification of the exocuticle initiated soon after the molt, but there was a delay between endocuticle matrix synthesis and calcification. Histology showed that the process of calcification was similar to that in other crustaceans. However, calcium concentrations within the exoskeleton continued to increase and never reached the levels of the inter-molt stage at the end of the experiment. This suggests that the Japanese mitten crab is relatively slow to calcify compared to other crustaceans.     

Subcutaneous Soft Tissue Sarcoma with Rhabdoid Features in a Dog

A nine-year-old male beagle dog had a white spherical mass in the subcutis of the left lumbar region. Microscopically, spindle to oval cells diffusely proliferated in the fibrous and myxoid stroma. Many neoplastic cells showed rhabdoid features or vacuolated cytoplasm. Immunohistochemically, the neoplastic cells were positive for vimentin and S100 and partly positive for neuron-specific enolase and glial fibrillary acidic protein but were negative for von Willebrand factor, desmin and α-smooth muscle actin. Ultrastructurally, the neoplastic cells had abundant cytoplasmic processes and desmosome-like structures. Cytoplasmic inclusions of rhabdoid-featured cells in HE sections were composed of aggregates of intermediate filaments, and cytoplasmic vacuoles were identified as an invagination of cytoplasm. Although malignant peripheral nerve sheath tumor was suggested according to these results, the present case was diagnosed as a soft tissue sarcoma with rhabdoid features due to a lack of identification of the basal lamina under electron microscopy.     

Maturity and reproduction of goneplacid crab <Emphasis Type="Italic">Carcinoplax vestita</Emphasis> (Decapoda,Brachyura) in Tokyo Bay

ABSTRACT:     Sexual maturity, morphological sexual dimorphism, and reproduction of the goneplacid crab Carcinoplax vestita were investigated in Tokyo Bay, Japan, from November 2002 to October 2003. The puberty molt in males was evidenced by changes in the relative size of the chelipeds and merus of the walking legs, and was estimated to occur at a size range of 13.20–18.85 mm carapace length. Post-pubertal females were identified by the relative size of the abdomen and puberty was estimated to occur at a size range of 12.81–15.46 mm carapace length. Sexual dimorphism in C. vestita was observed in all features that showed secondary sexual characteristics. Monthly changes of gonad index in males, and of seminal receptacle index and occurrence of sperm plugs in females were synchronized, and indicated that mating was intense in spring. Ovaries began developing in March. Ovigerous females were found in all months except December, but were clearly more abundant between August and October. Fecundity ranged from 7800 to 57 000 mature oocytes per female per batch and was highly correlated with body size. The results suggest that some females may spawn more than one batch per year.     

Patterns of stable carbon and nitrogen isotopes in the baleen of common minke whale Balaenoptera acutorostrata from the western North Pacific

ABSTRACT:   Stable carbon and nitrogen isotope ratios were determined in the baleen plates of 17 common minke whales Balaenoptera acutorostrata from the north-western Pacific Ocean off Japan, as well as prey species (krill Euphausia pacifica , Japanese anchovy Engraulis japonicus and Pacific saury Cololabis saira ) collected in the stomach contents, to investigate the trophic relationship between the minke whales and their prey. A few δ¹⁵N-depleted peaks occurred along the length of baleen plates for 10 males irrespective of stomach content (anchovies and sauries). Similar δ¹⁵N-depleted peaks were also found for one female and two immature individuals. It was likely that these δ¹⁵N-depleted peaks formed in early summer. The stable nitrogen isotope ratio (δ¹⁵N) values in Pacific saury (9.3 ± 1.4‰) did not differ significantly from that in Japanese anchovy (8.8 ± 0.9‰). In contrast, δ¹⁵N in krill (7.2 ± 0.5‰ in July and 8.0 ± 0.2‰ in September) were significantly lower than in the Pacific saury. Thus, these peaks may reflect the dietary change from krill to fishes in the feeding migration of the whales. Growth rate of the baleen plate was estimated to be 129 mm/y, and it appeared that a dietary record of about 1.4 years remained in the baleen plate. For two immature whales, the maximum value of δ¹⁵N occurred at the tip of baleen. This δ¹⁵N enrichment may possibly be useful for discriminating weanlings and older whales.