Blood parameters and electrocardiogram in squeezed fish simulating the effect of net damage and recovery

ABSTRACT:   In the present study, rubber bands were tied around the girth of rainbow trout Oncorhynchus mykiss to simulate and assess the physiological damage and survival rates of fish that encounter gill nets. Physiological condition was assessed by analysis of blood lactate, pH, oxygen partial pressure and plasma potassium concentration before and after release from binding. Twenty-four hours after release, half of the test fish had died. Although the binding forces used to hamper fish did not differ significantly, blood lactate levels in the dead fish rose to 10-fold higher than those in the survivors. Consequently, the pH level fell in the group that died, whereas in the surviving group it fell only slightly and soon recovered. Potassium concentration increased after release from binding in fish that died, and the P o ₂ levels in these fish continued to drop until just before death. It was concluded that when fish get entangled in fishing nets, blood lactate accumulates because of physical fatigue and the elevated lactate levels lead to metabolic acidosis. Finally, fatal metabolic conditions could cause higher mortality rates, even in escapees.     

A Model Analysis of Transport of Sulfur Oxides in China and Outflow to the Sea

A numerical analysis of modeled long-range transport of sulfur oxides in the continental areas of East Asia with some verification was introduced. Although several modeling studies on acidic deposition in East Asia have been done, only few cases have verified in wide areas. In this study, the model calculation has been compared with the monthly averaged sulfur concentration in precipitation observed at 69 locations widely covering China from July 1992 through January 1993. Additionally, the atmosphericSO₂ ⁹⁰Sr concentration along the east coast of the continent was also compared with the observation in May 1993, and found to be reasonably consistent. Basing on these comparisons, the budget of sulfur oxides in China, especially about the outflow from the east coast to the sea areas was examined considering the seasonal variation of distribution of wet deposition and the pathways of atmospheric sulfur oxides. The seasonal variation of these indices was found to have large difference between the north and the south of 35°N. The outflow from the east coast increased remarkably in winter due to the decrease of deposition in the inland areas along the transport pathways.     

Pathogenic diversity of Phytophthora sojae and breeding strategies to develop Phytophthora-resistant soybeans

Phytophthora stem and root rot, caused by Phytophthora sojae, is one of the most destructive diseases of soybean [Glycine max (L.) Merr.], and the incidence of this disease has been increasing in several soybean-producing areas around the world. This presents serious limitations for soybean production, with yield losses from 4 to 100%. The most effective method to reduce damage would be to grow Phytophthora-resistant soybean cultivars, and two types of host resistance have been described. Race-specific resistance conditioned by single dominant Rps (“resistance to Phytophthora sojae”) genes and quantitatively inherited partial resistance conferred by multiple genes could both provide protection from the pathogen. Molecular markers linked to Rps genes or quantitative trait loci (QTLs) underlying partial resistance have been identified on several molecular linkage groups corresponding to chromosomes. These markers can be used to screen for Phytophthora-resistant plants rapidly and efficiently, and to combine multiple resistance genes in the same background. This paper reviews what is currently known about pathogenic races of P. sojae in the USA and Japan, selection of sources of Rps genes or minor genes providing partial resistance, and the current state and future scope of breeding Phytophthora-resistant soybean cultivars.     

Epigenetic modulation on cat‐cow interspecies somatic cell nuclear transfer embryos by treatment with trichostatin A

This study aimed to determine the acetylation at lysine 9/18/23 of histone H3 (H3K9ac/H3K18ac/H3K23ac; H3K9/18/23 ac) and the di‐methylation at lysine 9 of histone H3 (H3K9me2) during early embryogenesis among trichostatin A (TSA)‐treated interspecies somatic cell nuclear transfer (iSCNT) cat‐cow (TSA‐iSCNT) embryos, TSA‐untreated iSCNT cat‐cow control (control) embryos and bovine in vitro fertilization (IVF) embryos, because TSA‐iSCNT embryos can develop to blastocysts. Compared to the control embryos, higher expressions of H3K9/18/23 ac were observed in TSA‐iSCNT embryos and IVF embryos at most following stages (2 h post‐fusion / post‐insemination (PF/PI) to eight‐cell stage). At 6 h PF/PI the expression of H3K9/23 ac in TSA‐iSCNT embryos and IVF embryos were lower than those in control embryos, and the expression of H3K18ac was no difference among the three groups. The expression of H3K9/23 ac increased in TSA‐iSCNT embryos and IVF embryos at pronuclear (PN) stages. The expression of H3K9me2 in TSA‐iSCNT embryos resembled that of IVF embryos at 2 h PF/PI to PN stages, and these expression levels were greater than those of control embryos. These results suggest that treatment of iSCNT embryos with TSA modifies the patterns of histone modification at certain lysine residues in a manner that is comparable with that seen in IVF during early embryogenesis.     

Interval mapping of growth quantitative trait loci in Japanese Black beef cattle using microsatellite DNA markers and half-sib regression analysis

A confirmatory scan for the regions of bovine chromosome 1 segregating the quantitative trait loci (QTL) influencing birthweight, weaning weight, yearling weight, and preweaning and postweaning average daily gains was performed by genotyping half‐sib progeny of four Japanese Black sires using microsatellite DNA markers. Data were analyzed by generating an F‐statistic every 1 cM on a linkage map by the regression of phenotype on the probabilities of inheriting an allele from the sire after adjusting for the fixed effects of sire, sex, parity and season of birth as well as age as a covariate. Permutation tests at chromosome‐wide significance thresholds were carried out over 10 000 iterations. A significant QTL for birthweight at 114 cM was detected in the sire 2 family. This identification of a birthweight QTL in Japanese Black cattle may be useful for the implementation of marker‐assisted selection.     

Intrafollicular Concentrations of Steroid Hormones and PGF2α in Relation to Follicular Development in the Mares during the Breeding Season

The concentrations of androstenedione, estradiol-17β, progesterone and PGF_2α contained in the follicular fluid produced by the follicles in collected ovaries of mares that have had estrous phase during the breeding season were measured and analyzed the relation between the growth stage of follicles and the hormone levels in the follicular fluid. An ultrasonographic diagnostic instrument was used to measure the diameter of the follicles in order to categorize the follicles into three groups the following: 8 small follicles (from 1.0 to less than1.5 cm), 8 medium follicles (from 1.5 to less than 3.0 cm), and 8 large follicles (from 3.0 to 5.0 cm), respectively. The analysis of the follicular fluid in ovaries of estrous mares showed that the concentrations of androstenedione were significantly higher in the medium or large follicles than in the small follicles and the concentrations of estradiol-17β were significantly higher in larger follicles than in the small or medium follicles (P<0.05). The concentrations of progesterone and PGF_2α, on the other hand, did not significantly vary regardless of follicluar size. In the follicles within the mare ovaries that have had estrous stage, the concentrations of the hormones related the ovulation, namely androstenedione and estradiol-17β, were higher with larger follicles.     

A BOLD-fMRI study of cerebral activation induced by injection of algesic chemical substances into the anesthetized rat forepaw

This study was performed to examine whether the brain activities induced by noxious algesic chemical substances in anesthetized animals could be detected by blood oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI). Multislice gradient echo images of the primary somatosensory cortex were obtained using a 7.05 T superconducting system and a one-turned surface coil centered over the primary somatosensory cortex of the 1.0%-isoflurane-anesthetized rat. The Z-score t-map of BOLD signals and its time-course analysis revealed that subcutaneous injection of formalin into the left forepaw immediately induced an early response in the contralateral primary sensory cortex lasting for a few minutes, followed by a late response until 20 min after stimulation. In contrast, injection of capsaicin into the left forepaw evoked only the early response. Furthermore, pretreatment with morphine completely abolished these responses induced by the chemical algesic substances. Thus BOLD-fMRI is a useful method to analyze the brain activities of painful stimulation in anesthetized animals.     

Comparison of the growth of age-1 Pacific saury <Emphasis Type="Italic">Cololabis saira</Emphasis> in the Western and the Central North Pacific

The growth of age-1 Pacific saury Cololabis saira was compared based on an analysis of the body-length frequency distributions, radius of the annual ring (otolith hyaline zones; ROH), and growth patterns in otolith increments. Fish were sampled at various locations between off the Japanese coast (144°E) and in the Central Pacific (160°W) in June and July 2006, and the measurements were compared among the stations ranging over six longitudinal areas, each with a longitudinal area of 10°. The mode of body-length frequency distributions of age-1 fish was larger in fish sampled west of 160°E (size class modes of 32.0–32.5 and 31.5–32.0 cm, respectively, in each 10° longitude area) than in those sampled east of 170°E (28.5–29.0 or 29.0–29.5 cm in 3 areas). The ROH was also larger in the former group (west of 160°E) than in the latter group (east of 170°E), but hatch periods of these two groups and age in days when the hyaline zones form in August or September did not differ based on the analysis of otolith growth increments. The growth difference occurred in the period between when the fish started their northward migration and when the hyaline zone was formed. These results indicate that the habitats of the two groups were separate until at least June or July of their second year of life.     

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...