Characterization of the suppressive effects of the biological control strain VAR03-1 of <Emphasis Type="Italic">Rhizobium vitis</Emphasis> on the virulence of tumorigenic <Emphasis Type="Italic">R. vitis</Emphasis>

Rhizobium vitis: strain VAR03-1 is a biological control agent that suppresses grapevine crown gall disease caused by a tumorigenic strain of R. vitis (Ti). Both acetosyringone-induced expression of a virulence gene and the growth of Ti were suppressed in vitro when it was cultivated in the VAR03-1 culture filtrate. These inhibitory effects were reduced by high-temperature treatment or incubation for 72 h. Both activities were detected in the high molecular weight fraction (>?100 kDa) of the filtrate. Our results suggest that the antagonistic effects of VAR03-1 on Ti are mediated by large particle(s) released in the culture media.     

The influence of fig proteases on the inhibition of angiotensin I‐converting and GABA formation in meat

The purposes of this research were to use fig protease for texture tenderizing, and to inhibit angiotensin I‐converting enzyme (ACE) action and γ‐aminobutyric acid (GABA) formation of meat. Liberated peptides by the enzymatic action of fig protease in processing meat and free amino acids were determined and ACE inhibitory activity was assayed. Meat treated with fig protease became tender as indicated by shear force value (SFV) which was half of those of non‐fig treated meat during storage even at 5°C. Liberated peptides, free amino acids and GABA increased while extremely low levels of Glu were detected after storage. The optimal temperature of fig protease against meat was 80°C. However, the activity of fig protease decreased after pre‐heating more than 40°C. High ACE inhibitory activity of a mixture of fig and meat was found around 80°C, and the value corresponded to the amount of liberated peptide. A lot of liberated peptides were found at 60–80°C and pasterization of meat product becomes convenient to produce peptides. Production of ACE inhibitory peptides and GABA can be expected as the healthy functional meat product such as antihypertensive activity and improve brain function.     

A serine proteinase from the sarcoplasmic fraction of red sea bream Pagrus major is possibly derived from blood

Collagen degradation is known to be involved in the post mortem tenderization of fish muscle. A serine proteinase that is assumed to be related to collagen degradation after fish death was purified from the sarcoplasmic fraction of red sea bream Pagrus major by ammonium sulfate fractionation and column chromatography on Sephacryl S-300, Q Sepharose and Phenyl Sepharose CL-4B. The enzyme hydrolyzed gelatin and was obtained as a protein band of approximately 38 kDa upon sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions. The N-terminal amino acid sequence of the enzyme was determined for 32 residues. A protein that had the same N-terminal amino acid sequence as the enzyme for ten residues was purified from the serum of red sea bream and showed the same characteristics as the enzyme. Therefore, it is suggested that the serine proteinase migrates from the blood to muscle and degrades muscle proteins after the death of the fish.     

Insect growth regulators with hydrazide moiety inhibit strigolactone biosynthesis in rice

Strigolactones (SLs) are carotenoid-derived plant hormones involved in several growth and developmental processes. Also, SLs are allelochemicals that induce the seed germination of root parasitic plants and the hyphal branching of arbuscular mycorrhizal fungi. In this study, to identify novel lead chemicals that inhibit SL biosynthesis, we evaluated the effect of agrochemicals on SL biosynthesis. We found that the diacylhydrazine insect growth regulator, chromafenozide, reduced the endogenous level of 4-deoxyorobanchol (4DO), a major SL in rice. Furthermore, treatment with the same class of insect growth regulator, methoxyfenozide, also resulted in the reduction of 4DO levels in rice root exudates. These results suggest that chromafenozide and methoxyfenozide are novel lead inhibitors of SL biosynthesis.     

Living Mulch with White Clover Improves Phosphorus Nutrition of Maize of Early Growth Stage

We examined the effect of a living mulch with white clover on the growth of maize in an Andisol. Maize was grown using a living mulch without fertilizer application, or by conventional cultivation with or without fertilizer application. Although the living mulch did not affect the amount of available phosphate in soil, the phosphorus concentration of maize shoots increased due to the living mulch compared with conventional cultivation without fertilizer application. Arbuscular mycorrhizal (AM) colonization of maize roots was higher with the living mulch than with conventional cultivation. These results suggested that a living mulch with white clover enhanced the phosphorus uptake by maize through AM colonization.     

黄瓜耐冷性遗传分析与连锁标记筛选

黄瓜(Cucumis sativusL.)是典型的冷敏型植物。对黄瓜来说,冷害是生产上制约其丰产、优质的主要逆境因素之一。为了掌握黄瓜耐冷性遗传规律,加快黄瓜耐冷品种的选育,本研究选取黄瓜耐冷型品系0839和低温敏感型品系B52为亲本杂交得到F1和F2,进行苗期低温鉴定和遗传分析。供试亲本的耐冷性主要受一对显性单基因控制。结合BSA(群体分离分析)和SSR分子标记,获得了与黄瓜耐冷性主效基因连锁的SSR标记。通过F2群体分析,鉴定出与耐冷性基因连锁的分子标记SSR07248,该标记与耐冷性基因间的遗传距离为32.6cM。     

Effect of shelter acclimation on the post-release survival of hatchery-reared black-spot tuskfish <Emphasis Type="Italic">Choerodon schoenleinii</Emphasis>: laboratory experiments using the reef-resident predator white-streaked grouper <Emphasis Type="Italic">Epinephelus ongus</Emphasis>

A critical component of many releasing projects is the identification and subsequent implementation of optimal release strategies that can decrease post-release predation mortalities. We performed laboratory experiments to investigate whether acclimation to shelters affects the post-release survival of hatchery-reared black-spot tuskfish Choerodon schoenleinii in the presence of a reef-resident predator, the white-streaked grouper Epinephelus ongus. Tuskfish were exposed to groupers under three different experimental conditions/treatments: (1) acclimation of fish to shelters prior to their exposure to groupers; (2) no acclimation of fish to shelters, but with shelters available during their exposure to groupers; (3) fish not acclimated to shelters and no shelters available during their exposure to groupers. Tuskfish that were acclimated to shelters utilized shelters more frequently than did non-acclimated fish, and the survival rate of acclimated fish was higher than those of fish in the other treatments. These results suggest that pre-release acclimation to shelters improves the post-release survival of hatchery-reared black-spot tuskfish.     

Dietary salmon milt deoxyribonucleic acid prevents hepatosteatosis in mice

With the increased incidence of lifestyle-related diseases, prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing at an unprecedented rate, leading to rising interest in studying the role of functional foods in its prevention. This study demonstrated the efficacy of salmon milt deoxyribonucleic acid (SM DNA) in preventing liver dysfunction in a diet-induced obesity model. Seven-week-old male C57BL/6J mice were fed normal diet (ND), high-fat diet (HFD), and HFD supplemented with 3% SM DNA (HFD?+?SM DNA) for 12 weeks. Increased body weight, fat-to-body weight ratio, and fat accumulation in HFD-fed mice demonstrated successful establishment of an obesity model. The HFD group showed increased alanine aminotransferase (ALT) levels, a marker of liver function, and NAFLD activity score (NAS) based on histological observations showed steatosis and mild inflammation but no fibrosis, indicating NAFLD but no nonalcoholic steatohepatitis. In the HFD?+?SM DNA group, the improved superoxide dismutase activity and NAFLD activity score suggested that SM DNA prevented liver dysfunction while maintaining antioxidant capacity and suppressing intrahepatocyte fat droplet formation. SM DNA attenuated fat accumulation in the liver and improved hepatic function. This study explored the potential of SM DNA as a functional food to prevent NAFLD and other visceral obesity-related diseases.

     

Otolith development and daily increment formation in laboratory-reared larval and juvenile black-spot tuskfish <Emphasis Type="Italic">Choerodon schoenleinii</Emphasis>

Microstructures of lapilli were examined for reared larvae and juveniles of black-spot tuskfish Choerodon schoenleinii. Lapilli of larvae at 1 day after hatching have one diffuse and obscure ring with an otolith radius of 4.3 ± 0.50 μm (mean ± SD, N = 8). The slope and intercept of the regression between the number of days after hatching and increment counts did not differ significantly from one and zero, respectively, indicating that lapillus increments were formed on a daily basis after hatching. There was an ontogenetic shift in the relative values of somatic and otolith growth, which corresponded to the transition from pelagic larvae to settlement stage. Simultaneously, the daily increment width reached the maximum value. These findings suggest that age at maximum value of increment width can be used as an indicator of the planktonic larval duration while settlement mark is not found. Since ontogenetic shift in the relationship between otolith radius and body size was observed, back-calculation of somatic growth in black-spot tuskfish using the otolith radius during the early life stages should be analyzed with caution, and the method requires further validation.     

Molecular mechanism of the S-RNase-based gametophytic self-incompatibility in fruit trees of Rosaceae

Self-incompatibility (SI) is a major obstacle for stable fruit production in fruit trees of Rosaceae. SI of Rosaceae is controlled by the S locus on which at least two genes, pistil S and pollen S, are located. The product of the pistil S gene is a polymorphic and extracellular ribonuclease, called S-RNase, while that of the pollen S gene is a protein containing the F-box motif, SFB (S haplotype-specific F-box protein)/SFBB (S locus F-box brothers). Recent studies suggested that SI of Rosaceae includes two different systems, i.e., Prunus of tribe Amygdaleae exhibits a self-recognition system in which its SFB recognizes self-S-RNase, while tribe Pyreae (Pyrus and Malus) shows a non-self-recognition system in which many SFBB proteins are involved in SI, each recognizing subset of non-self-S-RNases. Further biochemical and biological characterization of the S locus genes, as well as other genes required for SI not located at the S locus, will help our understanding of the molecular mechanisms, origin, and evolution of SI of Rosaceae, and may provide the basis for breeding of self-compatible fruit tree cultivars.