Comparison of low temperature adaptation ability in three native and two hybrid strains of the rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> species complex

The low temperature adaptation ability of five selected strains of the Brachionus plicatilis species complex, i.e., three native strains [ Japanese (NH1L), Australian, German] and two hybrid strains [♀NH1L and ♂Australian (N × A) and ♀NH1L and ♂German (N × G),was investigated in terms of life history traits, reproductive characteristics, and mobility under different thermal conditions (12 and 25 °C). The life history traits of these five strains included a longer lifespan, reproduction period and generation times at 12 °C than at 25 °C, combined with reduced lifetime egg and offspring production. At 12 °C, the intrinsic rate of natural increase was higher in NH1L and N × A strains. Reproductive characteristics determined at 12 °C by batch culture showed active population growth for NH1L and N × G strains, while no resting egg production was observed in all of the strains tested. The ratio of swimming rotifers at 12 °C was monitored every hour for 6 h (short term) and every day for 10 days (long term). In the short-term study there was a 81% ratio of swimming rotifers of the NH1L strain, while other strains exhibited low swimming ratios (<60%). In the long-term study NH1L and two hybrid strains showed a >75% swimming ratio from the initial day of the study. These results suggest that outcrossing of rotifer strains is useful to obtain live food resources for the larviculture of cold water fish.     

Synthesis of benzylaminopyrimidines and their fungicidal activities against wheat brown rust and barley powdery mildew

Members of a new class of fungicide containing benzylaminopyrimidine as a core structure were synthesized and their fungicidal potencies against wheat brown rust, Puccinia recondita, and barley powdery mildew, Erysiphe graminis, were assessed. Among these fungicides, N-(fluoroalkoxy or fluorophenoxybenzyl)-4-pyrimidinamines showed notable preventive activities. The potency of the new pyrimidines was increased when a difluoromethoxy or tetrafluorophenoxy group was introduced at the 4- or 3-position of the phenyl moiety and a methyl or ethyl group was introduced at the benzyl position. Structure–activity relationships are discussed. © 1998 Society of Chemical Industry     

Optimal germination condition by sulfuric acid pretreatment to improve seed germination of Sabina vulgaris Ant.

Understanding the germination traits of plants is important not only for understanding natural regeneration processes but also for developing seedling production techniques for planting. Sabina vulgaris Ant. is a common species used for reforestation in semi-arid areas of the Mu-Us Desert, in Inner Mongolia, China, but its extremely low germination rate, both in situ and in vivo, is a bottleneck for seedling production. Sulfuric acid pretreatment was applied to improve germination, and the germination rate was compared for different soaking time (10, 30, 60, 90, and 120 min), different temperatures (10, 15, 20, 30, and 35°C) and under different lighting conditions (dark and light). Sulfuric acid treatment gave a high germination rate, reaching 60% at 30 days after sowing. However, the non-treated seeds produced no germination. The optimal treatment time in sulfuric acid was 120 min. Germination after sulfuric acid treatment increased at incubation temperatures from 10 to 30°C, but decreased at 35°C. Incubation at 25–30°C gave maximum germination of more than 50%. Light treatment had little effect on germination. Pretreatment with sulfuric acid improved water absorption by the embryo by creating cracks and cavities in the seed coat tissue. These results indicated that S. vulgaris seeds have physical dormancy caused by their hard seed coats, which prevents absorption of water into the embryo. A combination of pretreatment with sulfuric acid and incubation at 25–30°C was most effective in improving the germination of S. vulgaris seeds.     

Effective rainfall seasons for interannual variation in δ13C and tree-ring width in early and late wood of Chinese pine and black locust on the Loess Plateau, China

We studied the importance of effective rainfall for interannual variation in water use efficiency (WUE) and tree-ring growth of Chinese pine (Pinus tabulaeformis Carr.) and black locust (Robinia pseudoacacia L.) by examining correlations of seasonal precipitation with annual values of stable carbon isotope ratio (δ¹³C) and tree-ring width in early and late wood. The correlations with precipitation were examined for each month and for periods of all possible lengths from 2 to 22 months starting from January of the previous year to October of the current year. The period with the highest correlation was adopted as the most effective rainfall season for interannual variations in WUE and tree-ring width. In early wood, precipitation during the dry season (October to May) before the growing season was negatively correlated with δ¹³C in pine trees and positively correlated with ring width in pine and locust trees. In late wood, rainfall during the growing season in the current year was negatively correlated with δ¹³C in pine and locust trees, and positively correlated with ring width in locust trees. Our results demonstrated the differences in the water use strategies of pine and locust trees. The δ¹³C in pines indicated higher WUE and more conservative water use than in locust trees. Precipitation during the dry season affected the interannual variation in WUE and tree-ring growth in pine and locust trees, indicating that rainfall during the dry season is important for carbon gain and tree-ring growth during the following growing season.     

Occurrence of all-<Emphasis Type="Italic">cis</Emphasis>-5,8,11,14,17,20,23-hexacosaheptaenoic acid (26:7n-3) in roughscale sole <Emphasis Type="Italic">Clidoderma asperrimum</Emphasis> flesh lipids

Fatty acid analysis of roughscale sole Clidoderma asperrimum flesh lipids was carried out by gas chromatography. An unidentified peak appeared in the chromatogram in the elution region of ≥C24 fatty acids. After enrichment by solvent partitioning, reversed-phase thin-layer chromatography (TLC), and argentation TLC, the peak component was subjected to structural analyses. The partially hydrogenated products after reaction with hydrazine hydrate gave seven isomers of cis-hexacosenoic acid (26:1). Gas chromatography-mass spectrometry (GC–MS) analyses of their dimethyl disulfide adducts identified the monounsaturates as 5-, 8-, 11-, 14-, 17-, 20-, and 23-26:1. The peak component was assigned to all-cis-5,8,11,14,17,20,23-hexacosaheptaenoic acid (26:7n-3). GC–MS analyses of the 4,4-dimethyloxazoline derivative and methyl ester confirmed this structure. This fatty acid is a rare, very long-chain polyunsaturated fatty acid (VLCPUFA). The concentrations of the acid found in roughscale sole were 0.69 ± 0.34% (N = 5) of total fatty acids in flesh lipids. Roughscale sole appears to be characterized by the occurrence of 26:7n-3, which is lacking in popular sources of methylene-interrupted VLCPUFA, such as vertebrate retina, spermatozoa, and herring.     

Correlation between acoustic emission, water status and xylem embolism in pine wilt disease

The occurrence of cavitation events and embolism during the latent, early stage and the late developmental stages of pine wilt disease was monitored nondestructively by acoustic emission (AE) and high-resolution magnetic resonance microscopy, respectively, and the results were compared with changes in leaf water potential and stem thickness. In the latent stage of the disease, when no embolisms were observed, cavitation events were detected by AE during the daytime in water-stressed Japanese black pine (Pinus thunbergii Parl.) seedlings, indicating that cavitation occurred at the individual tracheid level. In the early stage of the disease, an increase in the frequency of AE events occurred coincidentally with the occurrence of patchy embolisms at the mass tracheid level. The threshold water potential for such mass cavitation was higher than that causing cavitation of individual tracheids during the latent stage of the disease. In the advanced stage of the disease, explosive AE events were observed coincidentally with drastic enlargement of embolized areas and decreases in water potential. The AE events in the latent stage occurred only during the daytime, whereas, in the early and advanced stages of the disease, they also occurred at night. The explosive occurrence of cavitation in the advanced stage was thought to be a case of "runaway embolism."     

Growth characteristics,phytate contents,and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max (L.) Merr.) line

The phytic acid (myo-inositol hexakisphosphate or InsP₆) content of seed crops is important to their nutritional quality. Since it represents 75?±?10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2- and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl₂), starting at 15.7?mmol?L^?1. In tofu made from Tanbakuro, the concentration of MgCl₂ required to achieve the maximum breaking stress was 12.6?mmol?L^?1; however, it was 9.5?mmol?L^?1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3?mmol?L^?1 MgCl₂, but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl₂ concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl₂ concentration than that from high-phytate soybean cultivars.     

Variation of fruiting body productivity in protoplast fusants between compatible monokaryons ofLentinula edodes

Mycelial protoplasts of two compatible monokaryons ofLentinula edodes were prepared, and electro-fusion was undertaken. Sixteen dikaryons isolated after the electrofusion were tested for their fruiting abilities in comparison to the two dikaryons obtained by reciprocal mycelial mating. There were significant differences in fruiting body yield among the fusants, and some of them produced more fruiting bodies than did normally mated dikaryons. Although these dikaryons were divided into five genetically different groups by isozyme analyses and a cluster analysis, we could not find clear differences among the groups in terms of fruiting body yield, mycelial growth rate, or degree of wood decay. It appeared that fruiting body yield correlated positively with the mycelial growth rate but negatively with the degree of wood decay.     

Inhibition of Df-protease associated with allergic diseases by polyphenol.

It was reported that Df-protease from house dust mite (Dermatophagoides farinae) catalyzes the activation of the kallikrein-kinin system in human plasma and is closely associated with mite-induced allergy. Therefore, to prevent the release of kinin by Df-protease, the inhibitory activity of polyphenols including catechins and flavonols was tested in vitro and in vivo. Among them, myricetin and epigallocatechin gallate (EGCg) effectively inhibited the amidase activity of Df-protease with K(i) values of 1 x 10(-)(8) and 6 x 10(-)(4) M, respectively. The kinin release in human plasma was extensively inhibited by the addition of EGCg in comparison with myricetin. Enhancement of vascular permeability in guinea pigs caused by Df-protease was markedly suppressed by EGCg.     

Comparison of physicochemical properties of 7S and 11S globulins from pea, fava bean, cowpea, and French bean with those of soybean--French bean 7S globulin exhibits excellent properties

Legume seeds contain 7S and/or 11S globulins as major storage proteins. The amino acid sequences of them from many legumes are similar to each other in the species but different from each other, meaning that some of these proteins from some crops exhibit excellent functional properties. To demonstrate this, we compared protein chemical and functional properties (thermal stability, surface hydrophobicity, solubility as a function of pH, and emulsifying properties) of these proteins from pea, fava bean, cowpea, and French bean with those of soybean as a control at the same conditions. The comparison clearly indicated that the 7S globulin of French bean exhibited excellent solubility (100%) at pH 4.2-7.0 even at a low ionic strength condition (mu = 0.08) and excellent emulsion stability (a little phase separation after 3 days) at pH 7.6 and mu = 0.08, although the emulsions from most of the other proteins separated in 1 h. These results indicate that our assumption is correct.