Molecular characterization of the equine herpesvirus 1 strains RacL11 and Kentucky D

The pathogenicities of RacL11 and Kentucky D strains of equine herpesvirus 1 in the hamster infection model are different from those of Ab4p and the Japanese isolates. Virus genome restriction fragment length polymorphism analysis and sequence comparison of an intergenic region, glycoproteins and tegument genes showed higher conservation but with some strain-specific differences. These results indicate that point nucleotide differences in RacL11 and Kentucky D might be responsible for their pathogenicity in rodent models.     

cDNA cloning and complete primary structures of myosin heavy chains from brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso fast skeletal muscles

ABSTRACT:   The complete cDNA sequences encoding predominant types of myosin heavy chain (MYH) in the fast skeletal muscle were determined for brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso , which are used as materials for preparing high-quality surimi-based products. The cDNA consisted of 5973 and 5987 bp, respectively, and both encompassed an open reading frame encoding a polypeptide of 1936 amino acid residues. Brushtooth and wanieso lizardfish MYH showed the amino acid sequence identity of 92–93% to white croaker MYH, which was higher than that of 90% to walleye pollack MYH. The putative binding sites for ATP, actin, and regulatory and essential light chains in the subfragment-1 region of brushtooth lizardfish MYH exhibited a high identity with white croaker counterparts as well as the sequences of subfragment-2 and light meromyosin. In contrast, phylogenetic tree, constructed by the neighbor-joining method based on mitochondrial 16S rRNA gene, revealed that the two lizardfish species formed a cluster with walleye pollack, which was paraphyletic with white croaker. Therefore, a good reputation for lizardfish and white croaker to have a high thermal-gel forming ability seemed to be reflected by MYH rather than biological similarity as revealed by the mitochondrial 16S rRNA gene.     

Improvement in recruitment of Japanese sardine with delays of the spring phytoplankton bloom in the Sea of Japan

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS‐Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations from January 1998 to December 2015. Because relationships between SSChl a and in situ chlorophyll a concentrations were significantly different among periods based on the satellite combinations used, maximum and minimum SSChl a concentrations of 1 year were relativized as 1 and 0, respectively. Spatio‐temporal variation of relativized SSChl a concentrations was determined by using empirical orthogonal function (EOF) analysis. Scores in the first EOF mode denoted the basin‐scale variations of SSChl a concentrations in the Sea of Japan, and the major peak from the end of February to the end of May displayed the spring bloom. The logarithm of recruitment per spawner (LNRPS) for sardine was positively affected by delays in the start and end dates of the spring phytoplankton bloom. The delay of the date of the lowest sea surface temperature contributed to the delay of the end of the spring bloom during the period 1998–2015 and elevated the LNRPS during the period 1982–2015. Sardine spawns in the southern Sea of Japan from April to May, hence, delays of the spring bloom prolonged its overlap with sardine larval periods, and thus improved the recruitment of Japanese sardine in the Sea of Japan.     

Evaluation of cytokine messenger RNA expression in peripheral blood mononuclear cells from dogs with canine demodicosis

Using RT-PCR and semi-quantitative PCR, mRNA expression for canine interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-5, IL-10, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta in peripheral blood mononuclear cells (PBMCs) was examined in dogs with or without demodicosis. mRNA expression for IFN-gamma as well as TNF-alpha in dogs with demodicosis (localized (LD) and generalized (GD)) was slightly lower than those in dogs without demodicosis (healthy controls). Expression of IL-5 mRNA in dogs with demodicosis was higher than that in control dogs, but there were no significant differences in IL-4 and IL-10 mRNA expression levels among the three groups. On the other hand, expression levels of TGF-beta mRNA in dogs with GD were higher than those in control dogs and dogs with LD. The expression levels of IL-5 and TGF-beta mRNA decreased in all three dogs with GD which showed resolution of the clinical signs. Taken together, these results suggest that the Th2-like response in PBMCs from dogs with demodicosis is up-regulated, and that subsequent increased expression of IL-5 and TGF-beta mRNA in dogs with GD is reversible after treatment. Therefore, these cytokines, particularly IL-5, might be a useful clinical index of the clinical course in demodicosis. Also, increased TGF-beta mRNA expression might be a key factor for revealing the difference in the mechanism of onset between LD and GD.     

Accessory corpora lutea formation in pregnant Hokkaido sika deer (Cervus nippon yesoensis) investigated by examination of ovarian dynamics and steroid hormone concentrations

Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation.     

Seasonal changes in proteolytic enzymes of yellowtail Seriola quinqueradiata (Temminck & Schlegel; Carangidae) fed extruded diets containing different protein and energy levels

Seasonal variations in pepsin, trypsin and chymotrypsin activities and protein digestibility were studied in yellowtails (Seriola quinqueradiata) reared for 1 year with extruded diets containing different levels of protein. Trypsin and chymotrypsin storage levels in the digestive tissues of starved fish were affected by seasonal changes in water temperature. Actual digestion activities of trypsin and chymotrypsin were low at lower water temperatures, but pepsin activity in the stomach tissue was not affected by low temperatures. On the other hand, trypsin and chymotrypsin activities in the intestinal contents were higher during lower water temperature months, while pepsin activity in the stomach contents was low at lower water temperatures. Apparent protein digestibility (APD) did not differ among the dietary treatments in the higher water temperature months, while in colder months it was higher in fish fed diet 1 than in fish fed diets 2 and 3. The APD values reflected pepsin activity in the stomach contents in all sampling months. Therefore, lower APD in colder months seems to be attributed to lower protease activity in the gastric digesta, implying that enhanced pepsin secretion from the stomach tissue might improve protein digestibility and growth performance in yellowtails during winter.     

Architecture of succinate dehydrogenase and reactive oxygen species generation

The structure of Escherichia coli succinate dehydrogenase (SQR), analogous to the mitochondrial respiratory complex II, has been determined, revealing the electron transport pathway from the electron donor, succinate, to the terminal electron acceptor, ubiquinone. It was found that the SQR redox centers are arranged in a manner that aids the prevention of reactive oxygen species (ROS) formation at the flavin adenine dinucleotide. This is likely to be the main reason SQR is expressed during aerobic respiration rather than the related enzyme fumarate reductase, which produces high levels of ROS. Furthermore, symptoms of genetic disorders associated with mitochondrial SQR mutations may be a result of ROS formation resulting from impaired electron transport in the enzyme.