Genetic comparison between torafugu <Emphasis Type="Italic">Takifugu rubripes</Emphasis> and its closely related species karasu <Emphasis Type="Italic">Takifugu chinensis</Emphasis>

Abstract:   Sequence analyses of mitochondrial (mt) and nuclear genes were performed for genetic comparison between two Takifugu pufferfish species: torafugu T. rubripes and karasu T.  chinensis . With a sequence coverage of 20% in mtDNA, 640, 308, 344, 522 and 697 bp encoding mt 16S ribosomal RNA (rRNA), adenosine triphosphatase 6 ( ATPase 6 ), nicotinamide adenine dinucleotide dehydrogenase subunit 4 ( ND4 ), ND5 and cytochrome b (cyt b ), respectively, among 24 wild torafugu, 24 wild karasu and six hybrid-like samples, 15% of the torafugu identified by external color patterns showed nucleotide sequences consistent with karasu. Meanwhile, sequences of 60% karasu were consistent with those registered for torafugu (AJ421455). As for the hybrid-like samples, two possessed karasu-specific sequences in some base positions while torafugu-specific sequences in others. The remaining hybrid-like samples possessed torafugu-specific sequences. On the other hand, the mt control region did not show such type of consistency. Analysis of nuclear melanocortin receptor genes ( MC1R , MC4R ) among 54 samples showed 99–100% inter- and intraspecific sequence identity. Partial nuclear 18S  rRNA, complete internal transcribed spacer 1 ( ITS1 ), partial 5.8S  rRNA and ITS2 genes showed similar levels of identity, indicating a very low level of variation in their respective gene fragments between the two Takifugu species.     

Establishment of an Invasive Prostate Cancer Model in Transgenic Rats by Intermittent Testosterone Administration

We have established a transgenic rat for adenocarcinoma of the prostate (TRAP) model that features uniform adenocarcinoma development in prostatic lobes at high incidence within a short experimental period. However, no invasive carcinomas with reactive stroma characteristics similar to those in man were observed. We therefore have focused on a new model for invasive carcinoma of the prostate using TRAP rats. In experiment 1, male TRAP rats in groups 1 and 2 were treated with orchiectomy at day 0 of the experiment. Rats in groups 1–3 underwent testosterone propionate (TP) implantation from weeks 1 to 4 and from weeks 6 to 16. Rats in groups 1 and 3 were given 3,2’-dimethyl-4-aminobiphenyl (DMAB) after TP implantation. The rats of group 4 served as controls. In experiment 2, the rats were divided into three groups, none of which received DMAB or orchiectomy, treated with TP continuously or with the treatment withdrawn once or twice. In experiment 1, invasive adenocarcinomas with abundant collagenous stroma were found in the dorsolateral and anterior prostate, some of which showed perineural space invasion at week 16. The number of invasive carcinoma foci was most frequent in group 3. In experiment 2, invasive adenocarcinoma development in the lateral prostates was correlated with the number of TP administration/withdrawal cycles. In conclusion, our newly established rat model for invasive adenocarcinoma of the prostate could serve as a useful preclinical model for evaluating the in vivo efficacy of preventive and therapeutic agents targeting of the tumor microenvironment.     

Changes in metabolite concentrations in the abdominal muscle of the kuruma shrimp Marsupenaeus japonicus in response to different salinities

Invertebrates change the metabolite concentrations in their bodies to adapt to environmental salinity. The kuruma shrimp Marsupenaeus japonicus is one such invertebrate. It lives in coastal areas and is also known to change free amino acid concentrations depending on environmental salinity. To examine the relationship between the concentrations of metabolites, including amino acids, in the kuruma shrimp with environmental salinity, metabolome analysis was performed on the abdominal muscle of shrimps acclimated at 17, 34 and 40‰ salinity for 24 h. Principal component analysis revealed that the accumulation patterns of metabolites using the 111 metabolites detected in the shrimps exposed to different salinities were depicted in a salinity-dependent manner. The concentrations of alanine and glutamine were increased following exposure to increasing levels of salinity, suggesting that these free amino acids function in intracellular osmoregulation of the kuruma shrimp. Furthermore, the concentration of glycolytic metabolites was significantly decreased at high salinity. The concentrations of most of the metabolites related to the tricarboxylic acid (TCA) cycle also tended to decrease at high salinity. Considering the levels of expression of the genes related to various metabolic pathways, it seems that glycolysis is accelerated at high salinity.

     

不同处理方法和贮藏时间对野生大豆种子萌发的影响

采用人工小刀破皮、低温冷冻和浓硫酸处理研究其对野生大豆种子发芽的影响，实验表明：-6——-10℃低温冷冻处理野生大豆种子1、3、5、7、9d可以一定程度的提高种子的发芽率；用体积分数为0．98的浓硫酸处理种子8—10min，对提高野生大豆种子的发芽率有明显的促进作用，发芽率可高达98％。室内贮藏1—4年的种子其发芽率没有明显差异。     

Changes in rheological properties of grass carp fast skeletal myosin induced by seasonal acclimatization

To elucidate the effects of seasonal temperature acclimatization on thermal gelation of grass carp myosin, myosins from fish in different seasons were prepared and investigated for the changes in dynamic viscoelastic parameters including storage modulus (G′), loss modulus (G″) and damping factor (tan δ) upon heating. Myosins from fish in spring and summer had a temperature region of 38–44°C for the first marked increase of G′ higher than that of myosins from fish in autumn and winter (28–33°C). The measurement temperature-dependent changes in dynamic viscoelastic parameters such as G″ and tan δ were also different among the four myosins. While gel formation was observed with the spring and summer myosins, apparently in two steps, three steps were found in the autumn myosin. Furthermore, the winter myosin exhibited more than three steps for gel formation. These differences in rheological properties among the four myosins were considered to be attributed to the differences in thermodynamic and structural properties of these myosins previously reported.     

Qualitative and quantitative changes of F<Subscript>o</Subscript>F<Subscript>1</Subscript>-ATPase in Japanese flounder and red sea bream associated with rearing temperatures

ABSTRACT:   Fast skeletal muscles of Japanese flounder Paralichthys olivaceus and red sea bream Pagrus major were examined for quantitative and qualitative changes of mitochondrial ATP synthase (F_oF₁-ATPase) in association with rearing temperatures. The specific activities of F_oF₁-ATPase from Japanese flounder reared at 10°C, 15°C and 25°C for 4 weeks were determined to be 81 ± 11, 74 ± 13 and 83 ± 11 nmol/min·mg mitochondrial protein, respectively. The corresponding activity from red sea bream reared at 8°C for 5 weeks was determined to be 65 ± 9 nmol/min·mg mitochondrial protein, which was higher than 33 ± 9 nmol/min·mg mitochondrial protein in fish reared at 23°C. The contents of α- and β-F₁-ATPase in total mitochondrial proteins were not significantly different between fish reared at different temperatures for the two fish species. However, the contents of β-F₁-ATPase in the total fast skeletal muscle extracts, prepared from Japanese flounder reared at 10°C, were 2.1- and 2.9-fold higher than those for fish reared at 15°C and 25°C, respectively. The corresponding content from red seabream reared at 8°C was 2.2-fold higher than that for fish reared at 23°C. Therefore, the changes in F_oF₁-ATPase depending on rearing temperatures were species-specific.     

Differential expression of heat-shock proteins in F2 offspring from F1 hybrids produced between thermally selected and normal rainbow trout strains

Rainbow trout Oncorhynchus mykiss is a cold-water aquaculture species, and a thermally selected strain has been developed by multigenerational high-temperature breeding in Japan. We examined the expression of heat-shock proteins as candidates responsible for thermotolerance in rainbow trout using F2 offspring from F1 hybrids produced between thermally selected and normal strains. From F2 offspring, two groups were selected for western blot analysis, namely, low- and high-thermotolerance groups (times to loss of equilibrium were <30 and ??60?min, respectively). We demonstrated that the expression levels of Hsp70, Hsp60, and Hsp40 in tail fin tissues were significantly higher in the individuals with high thermotolerance than in those with low thermotolerance under non-heat-shock conditions. In particular, Hsp70 was expressed only in the individuals with high thermotolerance. These results suggest that Hsp70 is a major protein responsible for conferring thermotolerance in rainbow trout.     

Population model of Rana japonica crossing agricultural concrete canals: evaluating population conservation by improving the migration routes of frogs

Agricultural canals with deep concrete walls are commonly installed in paddy field areas following land consolidation projects in Japan. Such canals create a critical migration barrier for frogs, as escape is not possible after falling in. Hence, countermeasures that allow migrating frogs to cross agricultural canals, such as lid structures to prevent frogs from falling in or the creation of partial slopes to allow escape, have been developed to conserve endangered frog populations. The objective of this study was to design a method for evaluating the population viability of the endangered Japanese Brown Frog, Rana japonica, following the implementation of countermeasures. Two types of model simulations were examined: (1) a ??basic model,?? based on an age-structured model and (2) a ??crossing model,?? to evaluate migrating frogs crossing canals. Parameters, such as survival rate and fecundity, were estimated from field observation data of age-dependent population fluctuations. Comparison of a basic model simulation with the field observation data suggests model validation. The crossing model simulation, which had an initial population of 1,000 individuals, showed that a crossing proportion of greater than 30?C40% would achieve 95% population viability after 5?years. The simulation also showed that a crossing proportion of over 80% would also achieve 95% population viability after 40?years. These results indicate that frog survival during the migration period is insured, as long as no additional countermeasures are necessary after installation.     

Peripheral lymphocyte subsets as a prognostic indicator of mortality and morbidity in healthy dogs

To evaluate the relationship among immune status and increased morbidity and mortality, peripheral blood lymphocytes (CD3(+), CD4(+), CD8(+) and CD21(+) cells) from 32 healthy dogs over 8 years of age were analyzed. Twenty-five of the 32 dogs were followed-up for 3 years after the analysis; and 14 dogs were found to be diseased, and nine dogs died. There was no notable difference between the ages of the dogs that died compared with the ones that survived. The relative percentage of CD4(+) and the CD4(+):CD8(+) ratio decreased notably in dogs falling ill compared with healthy dogs. The relative percentage of CD3(+) lymphocytes showed a notable decrease in dogs that died within 3 years in comparison with dogs that survived. In a discriminant analysis of morbidity and mortality, most patients were correctly classified as diseased or not and surviving or dead, respectively. These results indicate that the immunophenotypes of peripheral blood lymphocytes in older dogs offer promise as parameters for evaluating mortality and morbidity.