Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: a report of six cases

Simultaneous removal of bilateral thyroid tumors was performed while preserving the parathyroid gland in six dogs. At least one external parathyroid gland was identified in all dogs. In five cases, the external parathyroid gland and its blood supply were preserved intact. In one dog, the vessels supplying the external parathyroid gland had been invaded by the tumor, and the gland was thus removed and reimplanted into the sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate and vitamin D₃. Local tumor recurrence was not observed in any of the cases. The mean survival time was 920 days. We found that the external parathyroid gland could be identified and preserved in most dogs undergoing total thyroidectomy.     

The infectivity and pathogenicity of a group 2 bovine coronavirus in pups

Canine respiratory coronavirus (CRCoV), which is more closely related to the bovine coronavirus (BCoV), has recently been detected in dogs. In this study, we examined whether BCoV was capable of infecting and exhibiting pathogenicity in dogs. Three 1-month-old pups were oronasally given field isolates of BCoV, and were kept together with 2 control animals. As a result, increases in BCoV-neutralizing antibody titers were confirmed in all pups in the challenged and control groups. Moreover, the virus gene was also detected in oral and rectal swabs by RT-PCR. These results indicate that BCoV infects dogs, and easily infects other dogs that are kept together. However, no clinical symptoms such as respiratory symptoms and diarrhea were observed.     

Spatial distribution analysis of the North Pacific spiny dogfish,Squalus suckleyi,in the North Pacific using generalized additive models

The North Pacific spiny dogfish (SPD), Squalus suckleyi, is a commercially exploited shark species that plays an important role in the ecosystem. To elucidate the distribution of the SPD in the North Pacific and to evaluate the effects of sea surface temperature (SST) and prey availability on its distribution, we estimated the probability of SPD presence using a generalized additive model with a binomial error distribution from SPD presence/absence data on 14,824 operations in fishery‐independent gillnet surveys between 1972 and 2011. The habitat model was structured in the east and west to reflect differences in the North Pacific oceanic environments. In the east, a higher probability of SPD presence was identified along the coast from the eastern Gulf of Alaska to Queen Charlotte Sound. In the west, it was identified around northern Japan. The estimated distribution was continuous between the two areas, whereas the probability of SPD presence was relatively low. Although the probability of SPD presence was higher at SSTs between 6°C and 12°C, the SST at the peak probability of SPD presence differed between the west and east. The prey species, Japanese sardine, Sardinops melanostictus, and walleye pollock, Gadus chalcogrammus, in the west and boreal clubhook squid, Onychoteuthis borealijaponica, in the east significantly affected the probability of SPD presence, which was higher if the prey species co‐existed with SPD. Therefore, SPD might adapt their distribution to that of available prey species. SPD stock assessment and management in these two important areas are required for its sustainable utilization.     

<Emphasis Type="Italic">Neoheterobothrium hirame</Emphasis> (Monogenea) alters the feeding behavior of juvenile olive flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

We monitored feeding behavior and survival of starved juvenile olive flounder experimentally infected with the gill monogenean Neoheterobothrium hirame. Infected flounder increased amount of the time spent in the water column by 117% when trying to capture live mysids, Neomysis sp. They also showed different feeding patterns from those of uninfected fish and made fewer attacks towards prey during one feeding attempt. Although the average numbers of mysids captured by individuals were similar between infected and uninfected fish, heavily infected fish tended to catch less prey. These results indicate that N. hirame reduces the feeding efficiency of the host for capturing live prey and possibly makes them more vulnerable to predation during feeding. We could not detect any obvious difference in survival rates between uninfected, lightly and heavily infected fish during 3 months of starvation. There was no evidence that starvation makes fish more susceptible to N. hirame. The present study provides first experimental evidence that N. hirame affects feeding behavior of juvenile olive flounder and supports the idea that this parasite indirectly reducing the host’s survival and may be responsible for the recent reduction of the flounder population in Japan.     

Age estimation by DNA methylation in the Antarctic minke whale

Fisheries Science - Determining the age of wild animals is very important in the study of their ecology and for stock assessment and management. In baleen whales, the most common approach for age...     

A single gene transfer of gibberellin biosynthesis gene cluster increases gibberellin production in a Fusarium fujikuroi strain with gibberellin low producibility

Fusarium fujikuroi, the causative agent of bakanae disease in rice, produces many kinds of secondary metabolites. Recently, two phylogenetic subgroups (F and G groups) of Japanese F. fujikuroi have been identified and found to have differences in their gibberellin (GA) and fumonisin production. G-group F. fujikuroi produces large amounts of GA, but is a fumonisin nonproducer. F-group produces large amounts of fumonisin, but is a GA low or nonproducer. We investigated the cause of low GA production in the F-group. Genetic mapping suggests that low GA production in the F-group strain Gfc0825009 is due to a GA gene cluster for GA biosynthesis. Analysis of the nucleotide and amino acid sequences of the genes in the GA gene cluster showed >98.4% homology between the F-group strain Gfc0825009 and the G-group strain Gfc0801001. Following a 7-day culture under low nitrogen conditions, we found that expression of P450-1, P450-4, and P450-2 in the cluster increased in the G-group strain and not in the F-group strain. We hypothesized that complementation by GA genes in the G-group strain would be required to increase GA production in the F-group strain. However, we found that this occurred with a single gene complementation of DES, P450-1, P450-4, or P450-2. Simultaneous increase in the expression of P450-1, P450-4, and P450-2 were detected in the complementary transformants. Moreover, the same phenomenon was observed by reintegration of its own P450-1. Our results suggest the presence of unknown regulatory mechanisms of the GA gene cluster in F. fujikuroi.     

Nitrification, ammonia-oxidizing communities, and N2O and CH4 fluxes in an imperfectly drained agricultural field fertilized with coated urea with and without dicyandiamide

Agricultural soil is a major source of nitrous oxide (N₂O), and the application of nitrogen and soil drainage are important factors affecting N₂O emissions. This study tested the use of polymer-coated urea (PCU) and polymer-coated urea with the nitrification inhibitor dicyandiamide (PCUD) as potential mitigation options for N₂O emissions in an imperfectly drained, upland converted paddy field. Fluxes of N₂O and methane (CH₄), ammonia oxidation potential, and ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) abundances were monitored after the application of PCU, PCUD, and urea to upland soil. The results showed that urea application increased the ammonia oxidation potential and AOB and AOA abundances; however, the increase rate of AOB (4.6 times) was much greater than that of AOA (1.8 times). These results suggested that both AOB and AOA contributed to ammonia oxidation after fertilizer application, but the response of AOB was greater than AOA. Although PCU and PCUD had lower ammonia oxidation potential compared to urea treatment, they were not effective in reducing N₂O emissions. Large episodic N₂O emissions (up to 1.59 kg N ha^?1 day^?1) were observed following heavy rainfall 2 months after basal fertilizer application. The episodic N₂O emissions accounted for 55–80 % of total N₂O emissions over the entire monitoring period. The episodic N₂O emissions following heavy rainfall would be a major source of N₂O in poorly drained agricultural fields. Cumulative CH₄ emissions ranged from ?0.017 to ?0.07 kg CH₄ ha^?1, and fertilizer and nitrification inhibitor application did not affect CH₄ oxidation.     

Reproductive biology of male skipjack tuna <Emphasis Type="Italic">Katsuwonus pelamis</Emphasis> (Linnaeus) in the tropical western and central Pacific Ocean

The reproductive biology of male skipjack tuna Katsuwonus pelamis was examined from May 2005 to December 2007 in the tropical western and central Pacific Ocean. Testis maturity was classified into five stages (i.e., immature, early maturation, mid maturation, late maturation, and regression) on the basis of morphological changes in the germinal epithelium. The testis duct system (TS), which was characterized by lobules that lack spermatocysts, store only sperm, and form an anastomosing network, was located under the main sperm duct. The TS was observed at all stages of maturity except the immature stage, and first appeared in individuals with a fork length (FL) of 38–40 cm. The estimated minimum size at first maturity was 35.5 cm FL and the size at 0.5 maturity was 40.7 cm in FL. It was difficult to clearly differentiate the testis maturity stage based solely on the gonad index (GI) class because each GI class contained mature fish. Monthly changes in testis height index and GI did not follow a seasonal cycle. Mature individuals dominated throughout the year. These results imply that male skipjack tuna in this area showed evidence of spawning activity throughout the year without a clear seasonal pattern.     

Biological features of canine cancer-associated fibroblasts and their influence on cancer cell invasion

Cancer-associated fibroblasts (CAFs) play an essential role in tumor invasion and metastasis. In dogs, the biological features of CAFs have not been well characterized. The purpose of this study was to investigate differences in the biological activities of canine CAFs and normal fibroblasts (NFs), and their influence on the migration and invasion of cancer cells. Canine CAFs and NFs were harvested from surgically-resected malignant epithelial tumor tissues and skin tissues of dogs. A wound-healing assay was conducted to compare the migratory and invasive abilities of canine CAFs and NFs. The results of this study showed that canine CAFs have a greater migratory and invasive ability than NFs. To observe the indirect and direct interactions between fibroblasts and cancer cells, Boyden chamber assay and 3D co-culture with collagen gel were conducted. The number of migrated and infiltrated cancer cells co-cultured with canine CAFs was greater than that with NFs. In the 3D co-culture, cancer cells showed noteworthy proliferation on the surface of gels containing canine CAFs and invasion into the gel. On the other hand, no infiltration of cancer cells into the gel containing NFs was observed. It was suggested that canine CAFs activate migration and invasion of cancer cells and promote the infiltration of cancer cells into collagen gels.