Insulin/insulin-like growth factor-like activity in the aqueous extracts of the rotifer Brachionus plicatilis

Insulin/insulin-like growth factor (IGF)-like signaling plays important roles in the aging processes of various animals. However, little is known about this signaling in rotifers, which have been used as a model animal in aging studies. Here we report that the aqueous extracts of the rotifer Brachionus plicatilis show activity similar to that of insulin/IGFs. Rotifers were cultured under four different feeding regimens (fed, starved for about ten days, or re-fed for 30 and 120 min after starvation), and then their aqueous extracts were added to culture media of rat L6 myoblasts. Treatment with these extracts increased the phosphorylation levels of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and two Akt substrates of approximately 48 and 60 kDa, and these phosphorylations were diminished when cells were preincubated with specific inhibitors of their upstream kinases (MAPK/ERK kinase and phosphoinositide 3-kinase, respectively). Furthermore, the extracts from fed rotifers provoked higher phosphorylation levels of MAPK/ERK and Akt substrates than the extract from starved rotifers, suggesting that the production of substance(s) with insulin/IGF-like activity is stimulated upon feeding in the rotifer.     

A preliminary study to understand the transport process for the eggs and larvae of Japanese Pacific walleye pollock Theragra chalcogramma using particle-tracking experiments based on a high-resolution ocean model

We developed a realistic 1/50° high-resolution ocean model capable of resolving submesoscale variability, and performed particle-tracking experiments based on this ocean model to identify elements that significantly affect the transport of the eggs and larvae of the Japanese Pacific walleye pollock Theragra chalcogramma into Funka Bay. The high-resolution model reproduced representative features of the oceanographic conditions of the main spawning area and season. A comparison of particle-tracking experiments performed under the passive transport condition based on high-resolution (1/50°) and low-resolution (1/10°) ocean models showed that high-resolution modeling is essential in order to realistically simulate the transport process. In this regard, however, the vertical motion of particles cannot be explained by the passive transport condition, as it leads to unrealistically deep sinking of particles in the simulation. Turning our attention to feasible non-passive transport conditions, we then incorporated the buoyancy motion of particles and conducted additional experiments that mainly differed in the particle density adopted. We clarified that buoyancy is an important factor in the retention of particles near the sea surface, and that the ratio of the particles that remain in Funka Bay to the number of particles released is sensitive to the vertical motions/positions of the particles, implying that it is necessary to model this vertical motion more accurately by incorporating more realistic biological processes or a statistical distribution into the particle-tracking model.     

Recent studies on biological control of plant diseases in Japan

Microorganisms play an enormously important role in plant disease control. Research on biological control of plant pathogens has received major impetus and attracted many researchers during the past few decades due to the increased public concern on hazards associated with the use of synthetic pesticides. From research on utilizing specific antagonistic microorganisms, many effective biological control agents (BCAs) have been found and are increasingly implemented in integrated pest management strategies to control plant diseases. Here current research results on biological control against plant diseases carried out in Japan are reviewed by focusing on major categories of BCAs: fungi, bacteria and actinomycetes and attenuated viruses.     

Bacterial leaf spot and blight of crucifer plants (Brassicaceae) caused by Pseudomonas syringae pv. maculicola and P. cannabina pv. alisalensis

Bacterial leaf spot and blight diseases caused by Pseudomonas syringae pv. maculicola (Psm) and P. cannabina pv. alisalensis (Pcal) are becoming a significant concern for producers of crucifer crops worldwide. Since Psm was first described in 1911, many have reported on its diverse phenotypic, genetic and pathogenic characteristics. Japanese isolates of Psm are also heterogeneous and differ in their host preferences. Pcal was first described in 2002 and has quickly spread globally. Recent work demonstrated that some isolates that had been identified as Psm are actually Pcal. Pcal was also shown to be split into two groups, A and B, based on bacteriological properties, genetic traits and pathogenicity. Group A of Pcal consists mostly of isolates from Japanese radish and radish, isolated before 1990s, that are more aggressive on radish leaves but less aggressive on other Brassica plants compared with group B. Group B of Pcal consists of recent isolates from various crucifer plants including the pathotype of Pcal. In this review, we suggest that group A of Pcal may have existed since the 1950s and survived as a relatively minor pathogen on radish or Japanese radish, whereas group B emerged in the late 1990s, causing global epidemics because of its stronger virulence on various Brassica crops. We also suggest that emergence of a new group of a pathogenic bacterium may cause a re-emergence or new epidemics of a disease that previously was of minor importance.     

Geographical variation in spawning histories of age-1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July

Fisheries Science - We examine geographical differences in percentages of age-1 Pacific saury Cololabis saira with previous spawning experience collected from 143°E to 165°W during June...     

Tracheal stenosis following endotracheal intubation in a dog

A 2-month-old intact female Rottweiler was presented for investigation of coughing and respiratory distress 9 d after an exploratory laparotomy for intestinal foreign body removal. Tracheal stenosis was suspected by radiography and confirmed with computed tomography (CT) and tracheoscopy. After 1 wk of medical management, clinical signs had resolved and the severity of the tracheal narrowing was markedly improved, as confirmed by radiography and tracheoscopy. Tracheal stenosis is a considerable complication of endotracheal intubation in veterinary medicine and may be medically managed, depending on the severity of the tracheal injury.Key clinical message:To our knowledge, this is the first clinical case report of tracheal stenosis resulting from endotracheal intubation in a dog and its resolution after medical management.     

rasH2 mouse: reproducibility and stability of carcinogenicity due to a standardized production and monitoring system

The rasH2 mouse was developed as a model for carcinogenicity studies in regulatory science. Its phenotype is stable during high-volume production and over successive generations. To produce rasH2 mice, three strains of mice (C57BL/6J-TgrasH2, C57BL/6J, and BALB/cByJ) were maintained individually. Since the homozygous c-HRAS genotype is lethal, hemizygous transgenic mice were maintained by crossing with inbred C57BL/6J mice. After breeding, male B6-transgenic mice were mated with female BALB/cByJ mice to obtain transgenic mice. Pups that were rasH2-Tg (tg/wt) or rasH2-Wt (wt/wt) were confirmed by genotyping. Frozen embryos were preserved by the Central Institute for Experimental Animals (CIEA) and sent to two facilities, CLEA Japan and Taconic Biosciences, where the mice were produced. Production colonies are created in both facilities and supplied to customers worldwide. To prevent genetic drift, the colonies were renewed for up to 10 generations, and renewals were carried out four times every five years from 2005 to 2021. To ensure the uniformity and maintenance of the phenotype of rasH2 mice, the carcinogen susceptibilities were monitored in every renewal of colonies by CIEA based on a standard protocol of the short-term carcinogenicity study using the positive control compound N-methyl-N-nitrosourea (MNU). Furthermore, simple carcinogenicity monitoring targeting the forestomach, the organ most sensitive to MNU, was performed approximately once a year. Based on the optimally designed production and monitoring systems, the quality of rasH2 mice with reproducibility and stability of carcinogenicity is maintained and supplied globally.     

Constituents from aerial parts of Wedelia paludosa.

Tetrachyrin (1), 3alpha-tigloyloxykaur-16-en-19-oic acid (2) and 3alpha-cinnamoyloxykaur-16-en-19-oic acid (3) have been isolated from the ethanol extract of Wedelia paludosa aerial parts.