Factor analysis of risk-taking behavior in forest work

In this study, the data obtained by a questionnaire survey were analyzed to examine the difference with the type of occupation, consistency in each situation, the inductive and restraint factors of the risk-taking behavior in the forest work to elucidate the risk-taking behavior in forest work. The results showed that (1) the Kyushu Forest Cooperative Association’s staff members underestimate the risk, but have a strong recognition of “law observance,” (2) the supervisor or instructor has low consciousness of risk, (3) as the inductive factor of behavior, one’s own benefit in the daily situation is given the highest priority, but risk is the most important factor in situations concerning forest work and forest machine operation and handling, irrespective of the accuracy of the risk evaluation, (4) as the restraint factor of behavior, although there is a difference in the risk evaluation whether large or small, risk is given priority by all workers, and (5) the dare probability of each risk-taking behavior is highly correlated with the risk evaluation of the behavior. Among others, low consciousness of the supervisor or instructor concerning safety management is pointed out as a main factor in worker’s accidents, and reconsideration of the relationship between the supervisor or instructor and workers is necessary.     

Natural foods utilized by Nile tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, in fertilizer-based fish ponds in Lao PDR identified through stable isotope analysis

Nile tilapia, Oreochromis niloticus, is one of the most popular freshwater aquaculture species in developing countries. Although formulated feed provides higher fish yield, it is expensive. Therefore, fertilizer-based fish culture using natural food sources is generally implemented in developing countries. The aim of this study was to identify the major natural foods contributing to tilapia growth in fertilizer-based fish ponds. The stomach contents of tilapia in a fertilizer-based fish pond in Lao PDR were analyzed to estimate their feeding behaviors; stable isotope ratios of carbon and nitrogen in the potential food organisms and suspended solids were measured and compared with the ratios in the fish muscle tissues. Further, the feed efficiency of chironomid larvae was compared with that of chlorella and formulated feed in a laboratory feeding experiment. Consequently, chironomid larvae were identified as the main contributors to tilapia growth in the fertilizer-based fish pond. In conclusion, benthic larvae of insects belonging to the family Chironomidae are confirmed to be a natural food source for tilapia in the fertilizer-based fish pond.     

Hepatoprotective and antioxidant effects of dietary Angelica sinensis extract against carbon tetrachloride‐induced hepatic injury in Jian Carp (Cyprinus carpio var. Jian)

The present study aimed to evaluate the hepatoprotective effects of Angelica sinensis extract (ASE) against carbon tetrachloride (CCl₄)‐induced hepatotoxicity in Jian carp (Cyprinus carpio var.Jian). Fish were fed diets containing four doses of ASE (0%, 0.1%, 0.5% and 1.0%) for 60 days, and then given an intraperitoneal injection of 30% CCl₄ in olive oil at a volume of 0.05 mL/10 g body weight. At 72 h post injection, blood and liver samples were collected for biochemical analysis, comet assay, histopathological examination and CYP3A mRNA expression. Results showed that the increases of glutamate pyruvate transaminase (GPT) and glutamate oxalate transaminase (GOT) induced by CCl₄ were significantly inhibited by pre‐treating the fish with 0.1%, 0.5% and 1.0% ASE in the diets. The elevation of lactate dehydrogenase (LDH) and the reductions of the total protein (TP) and albumin (Alb) in the serum induced by CCl₄ were also inhibited by pre‐treatments with 0.5 and 1.0% ASE. In the liver tissue, pre‐treatment with 1.0% ASE significantly inhibited the malondialdehyde (MDA) formation and the reductions of the total antioxidant capacity (T‐AOC), superoxide dismutase (SOD), glutathione (GSH) and CYP3A mRNA expression induced by CCl₄. Comet assay showed that tail moment, olive tail moment, tail length and tail DNA% were positively changed in fish pretreated with 0.5 and 1.0% ASE. CCl₄‐induced histological changes were obviously reduced by 0.5% and 1.0% ASE. Overall results prove the hepatoprotective effect of ASE in a dose‐dependent manner and support the use of ASE (1.0%) as a hepatoprotective and antioxidant agent in fish.     

MiFish metabarcoding: a high-throughput approach for simultaneous detection of multiple fish species from environmental DNA and other samples

Fisheries Science - We reviewed the current methodology and practices of the DNA metabarcoding approach using a universal PCR primer pair MiFish, which co-amplifies a short fragment of fish DNA...     

Suitability of Japanese codling as a raw material for surimi-based products revealed by primary sequence analysis of myosin heavy chain and thermal gel properties

Fisheries Science - Complementary DNA encoding a part of myosin heavy chain was cloned from fast skeletal muscle of Japanese codling Physiculus japonicus. Japanese codling, a frequent catch off the...     

Swimming angle and target strength of larval Japanese anchovy (<Emphasis Type="Italic">Engraulis japonicus</Emphasis>)

The swimming angle of larval Japanese anchovy (Engraulis japonicus) was measured in a tank, and target strength (TS) was calculated using a theoretical scattering model. The mean swimming angle was 12.8° (SD ±22.1). Increased speeds of flow led to increased mean swimming angles. The mean swimming angle at flow of 5 cm s⁻¹ was higher than at other speeds. TS values were estimated using a distorted-wave Born approximation model for two cases. Average values were 1–3 cm s⁻¹ (11.5° ± 22.1) and 5 cm s⁻¹ (16.6° ± 21.7) for cases 1 and 2, respectively. For case 1, TS ranged from −92.0 to −74.7 dB with a mean of −79.4 dB at 120 kHz. For case 2, TS ranged from −92.2 to −75.2 dB with a mean of −79.9 dB. The mean TS in case 2 was lower than that in case 1, with the maximum difference being 1.0 dB at 120 kHz (standard length 22.0 mm). However, there were no significant differences between the regression lines of cases 1 and 2. Thus, changes in flow speed altered the swimming angle of larval Japanese anchovy, but had little influence on TS.     

Measurements of density contrast and sound-speed contrast for target strength estimation of Neocalanus copepods (Neocalanus cristatus and Neocalanus plumchrus) in the North Pacific Ocean

The mass density and sound-speed contrasts against surrounding seawater (g and h, respectively) of Neocalanus copepods (N. cristatus and N. plumchrus) were measured in 2006 and 2007 to compute the theoretical target strength (TS). The values of g ranged from 0.997 to 1.009 in N. cristatus and from 0.995 to 1.009 in N. plumchrus. There were no correlations between prosome length (PL) and g. The values of h ranged from 1.006 to 1.021 in N. cristatus and from 1.013 to 1.025 in N. plumchrus and varied with changes in temperature. TS was estimated with the theoretical sound scattering model using the values of g and h based on the temperature, salinity, and depth of the location where the specimens were collected. Regressions of the tilt-averaged TS versus PL were obtained at 38, 120, and 200 kHz. The averaged TS of N. cristatus and N. plumchrus at 120 kHz, which is widely used as a high frequency, ranged from −110.0 to −103.1 dB and from −121.4 to −109.7 dB, respectively. There was a positive correlation between frequency and averaged TS: the higher the frequency, the higher the value of averaged TS. The TS at 120 and 38 kHz varied from 14.8 to 16.4 dB in N. cristatus and from 17.9 to 18.7 dB in N. plumchrus, respectively; that at 200 and 120 kHz varied from 2.9 to 5.5 dB in N. cristatus and from 5.3 to 6.5 dB in N. plumchrus, respectively.     

Sat-BSA: an NGS-based method using local de novo assembly of long reads for rapid identification of genomic structural variations associated with agronomic traits

Advances in next generation sequencing (NGS)-based methodologies have accelerated the identifications of simple genetic variants such as point mutations and small insertions/deletions (InDels). Structural variants (SVs) including large InDels and rearrangements provide vital sources of genetic diversity for plant breeding. However, their analysis remains a challenge due to their complex nature. Consequently, novel NGS-based approaches are needed to rapidly and accurately identify SVs. Here, we present an NGS-based bulked-segregant analysis (BSA) technique called Sat-BSA (SVs associated with traits) for identifying SVs controlling traits of interest in crops. Sat-BSA targets allele frequencies at all SNP positions to first identify candidate genomic regions associated with a trait, which is then reconstructed by long reads-based local de novo assembly. Finally, the association between SVs, RNA-seq-based gene expression patterns and trait is evaluated for multiple cultivars to narrow down the candidate genes. We applied Sat-BSA to segregating F₂ progeny obtained from crosses between turnip cultivars with different tuber colors and successfully isolated two genes harboring SVs that are responsible for tuber phenotypes. The current study demonstrates the utility of Sat-BSA for the identification of SVs associated with traits of interest in species with large and heterozygous genomes.