A size-structured model for a stock-recovery program for an exploited endemic fisheries resource

The size of harvests temporarily decreases following stock-recovery programs for overexploited resources. The process of stock recovery is quite uncertain, because of unknown life-history parameters, changes in environmental conditions, and human impact. To project future stock recovery, we considered a size-structured matrix model of a stock-recovery program, in which the minimum body size in the first harvest is increased. We applied some common concepts, including yield per recruitment, spawning per recruitment, and reproductive value, to a size-structured matrix model that incorporated economic discounting. The size-structured model predicted the following characteristics in stock-recovery processes: several years must pass for the harvest to increase, and the time-lag between the inception of the management program and the increase in the catch is caused by intergenerational momentum in demography. We also investigated the effects on the recovery process of temporal environmental fluctuations. We applied our model to a stock-recovery program of the corbiculid Seta clam (Corbicula sandai) in Lake Biwa, Japan.     

Anti-Mycobacterial Nucleoside Antibiotics from a Marine-Derived Streptomyces sp. TPU1236A

Five new nucleoside antibiotics, named streptcytosines A–E (1–5), and six known compounds, de-amosaminyl-cytosamine (6), plicacetin (7), bamicetin (8), amicetin (9), collismycin B (10), and SF2738 C (11), were isolated from a culture broth of Streptomyces sp. TPU1236A collected in Okinawa, Japan. The structures of new compounds were elucidated on the basis of their spectroscopic data (HRFABMS, IR, UV, and 2D NMR experiments including ¹H-¹H COSY, HMQC, HMBC, and NOESY spectra). Streptcytosine A (1) belonged to the amicetin group antibiotics, and streptcytosines B–E (2–5) were derivatives of de-amosaminyl-cytosamine (6), 2,3,6-trideoxyglucopyranosyl cytosine. Compound 1 inhibited the growth of Mycobacterium smegmatis (MIC = 32 µg/mL), while compounds 2–5 were not active at 50 µg/disc. Bamicetin (8) and amicetin (9) showed the MICs of 16 and 8 µg/mL, respectively.     

Chlorantraniliprole application differentially affects adult emergence of Sympetrum dragonflies in rice paddy fields

Paddy and Water Environment - Rice paddy fields are important habitat for many dragonfly species. In Japan, populations of dragonflies inhabiting rice paddies, in particular Sympetrum (Odonata:...     

Evaluating the impact of COVID-19 on ex-vessel prices using time-series analysis

The spread of coronavirus disease 2019 (COVID-19) and subsequent lockdown measures have impacted economies and industries worldwide. The fisheries industry witnessed a sharp decline in demand and a slump in fish prices due to its dependence on the food service industry. It is important to quantitatively assess those fish species affected most and the extent of the pandemic’s impact on them, to take specific countermeasures. We propose a time-series analysis as an alternative to the current practice of using ad hoc year-on-year comparisons. Although the pandemic makes it difficult to construct a counterfactual approach due to the lack of an appropriate control group, we use time-series forecasting to simulate normal conditions using pre-pandemic data. In Tokyo, the unit price of fish species that were negatively impacted by the food services industry dropped by 12.65% to 14.64%, and by 26.08% to 28.22% after the declaration of a state of emergency. Seasonality, short weekly cycles, and short-term market trends are factors that affect the price of fish. Species-specific impact estimates related to the COVID-19 pandemic can allow policymakers to implement recovery measures in a more targeted and effective manner. The results of our analysis can increase fishers’ and policymakers’ awareness of the usefulness of economic analyses and incentivize them to release data to establish a system to accumulate and analyze data strategically for urgent and appropriate interventions in the fisheries industry.

     

Fish meal vs. corn gluten meal as a protein source for dry cat food.

To compare the effects of two dietary protein sources, fish meal (FM) and corn gluten meal (CGM), fecal moisture content, nitrogen balance and urinary excretion were examined in adult cats. The dietary protein source did not cause a significant difference in daily food intake, water intake, urine volume, dry matter digestibility or urinary nitrogen excretion, but fecal moisture content was lower (P<0.02) in the CGM group. The HCl-insoluble fraction of urinary sediment tended to be higher in the CGM group (P<0.10), although urinary pH was similar in the two groups. These results suggest that CGM is comparable with FM in respect to nutritional value and the urine acidifying effect, but FM may be preferable to CGM for the prevention of constipation and struvite urolithiasis in cats.     

Identification of a novel cytotoxic protein, Cry45Aa, from Bacillus thuringiensis A1470 and its selective cytotoxic activity against various mammalian cell lines

Parasporal inclusion proteins produced by Bacillus thuringiensis strain A1470 exhibit strong cytotoxicity against human leukemic T cells when activated by protease treatment. One of the cytotoxic proteins was separated by anion exchange chromatography and gel filtration chromatography and designated Cry45Aa. Its gene was then expressed in recombinant Escherichia coli, in which the Cry45Aa precursor was accumulated in an inclusion body. It was solubilized in sodium carbonate buffer and processed with proteinase K, and cytotoxic activities of the protein against various mammalian cell lines were evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assay. The protein exhibited high cytotoxic activity against CACO-2, Sawano, MOLT-4, TCS, and HL60 cells and moderate activity against U-937 DE-4, PC12, and HepG2 cells. On the other hand, the EC50 values against Jurkat, K562, HeLa, A549, Vero, COS-7, NIH3T3, CHO, and four normal tissue cells (human primary hepatocyte cells, UtSMC, MRC-5, and normal T cells) were >2 microg/mL.     

Applicability of Aegilops tauschii drought tolerance traits to breeding of hexaploid wheat

Few genes are available to develop drought-tolerant bread wheat (Triticum aestivum L.) cultivars. One way to enhance bread wheat’s genetic diversity would be to take advantage of the diversity of wild species by creating synthetic hexaploid wheat (SW) with the genomic constitution of bread wheat. In this study, we compared the expression of traits encoded at different ploidy levels and evaluated the applicability of Aegilops tauschii drought-related traits using 33 Ae. tauschii accessions along with their corresponding SW lines under well-watered and drought conditions. We found wide variation in Ae. tauschii, and even wider variation in the SW lines. Some SW lines were more drought-tolerant than the standard cultivar Cham 6. Aegilops tauschii from some regions gave better performing SW lines. The traits of Ae. tauschii were not significantly correlated with their corresponding SW lines, indicating that the traits expressed in wild diploid relatives of wheat may not predict the traits that will be expressed in SW lines derived from them. We suggest that, regardless of the adaptability and performance of the Ae. tauschii under drought, production of SW could probably result in genotypes with enhanced trait expression due to gene interactions, and that the traits of the synthetic should be evaluated in hexaploid level.     

Resetting central and peripheral circadian oscillators in transgenic rats

In multicellular organisms, circadian oscillators are organized into multitissue systems which function as biological clocks that regulate the activities of the organism in relation to environmental cycles and provide an internal temporal framework. To investigate the organization of a mammalian circadian system, we constructed a transgenic rat line in which luciferase is rhythmically expressed under the control of the mouse Per1 promoter. Light emission from cultured suprachiasmatic nuclei (SCN) of these rats was invariably and robustly rhythmic and persisted for up to 32 days in vitro. Liver, lung, and skeletal muscle also expressed circadian rhythms, which damped after two to seven cycles in vitro. In response to advances and delays of the environmental light cycle, the circadian rhythm of light emission from the SCN shifted more rapidly than did the rhythm of locomotor behavior or the rhythms in peripheral tissues. We hypothesize that a self-sustained circadian pacemaker in the SCN entrains circadian oscillators in the periphery to maintain adaptive phase control, which is temporarily lost following large, abrupt shifts in the environmental light cycle.