Allelic variation of a clubroot resistance gene (Crr1a) in Japanese cultivars of Chinese cabbage (Brassica rapa L.)

Clubroot resistance (CR) is an important trait in Chinese cabbage breeding worldwide. Although Crr1a, the gene responsible for clubroot-resistance, has been cloned and shown to encode the NLR protein, its allelic variation and molecular function remain unknown. Here, we investigated the sequence variation and function of three Crr1a alleles cloned from six CR F₁ cultivars of Chinese cabbage. Gain-of-function analysis revealed that Crr1a^Kinami90_a isolated from the cv. ‘Kinami 90’ conferred clubroot resistance as observed for Crr1a^G004. Because two susceptible alleles commonly lacked 172 amino acids in the C-terminal region, we investigated clubroot resistance in transgenic Arabidopsis harboring the chimeric Crr1a, in which 172 amino acids of the functional alleles were fused to the susceptible alleles. The fusion of the C-terminal region to the susceptible alleles restored resistance, indicating that their susceptibility was caused by the lack of the C-terminus. We developed DNA markers to detect the two functional Crr1a alleles, and demonstrated that the functional Crr1a alleles were frequently found in European fodder turnips, whereas they were rarely introduced into Japanese CR cultivars of Chinese cabbage. These results would contribute to CR breeding via marker-assisted selection and help our understanding of the molecular mechanisms underlying clubroot resistance.     

A new method for evaluating symplastic cadmium absorption in the roots of Solanum melongena using enriched isotopes 113Cd and 114Cd

Radioisotope techniques are well known as methods for evaluating symplastic ion absorption in roots. In the present study, a new method for evaluating symplastic cadmium (Cd) absorption in plant roots was developed using the enriched isotopes ¹¹³Cd and ¹¹⁴Cd. Seedlings of Solanum melongena were exposed to an enriched isotope solution of ¹¹³Cd at 25°C for 30 min. The roots were excised from each seedling and were then immersed in a cold buffer solution without Cd at 2°C for 120 min to suppress the metabolic activity of the roots. Finally, the roots were treated with a cold buffer solution containing enriched stable isotope ¹¹⁴Cd at 2°C for 120 min, whereby the apoplastically bound ¹¹³Cd was desorbed. We tested the validity of our method for evaluating symplastic Cd in roots compared with the conventional method based on differences in the amount of Cd absorbed at 2°C and 25°C using unlabeled Cd. There was no difference in the symplastic Cd content of the roots between the two methods. These results indicate that it is possible to evaluate the symplastic Cd content in roots using the enriched isotopes ¹¹³Cd and ¹¹⁴Cd.     

Effects of Dietary Vitamin C on Blood Chemistry and Nonspecific Immune Response of Juvenile Red Sea Bream,Pagrus major

A trial was conducted to determine the effect of ascorbyl‐2‐monophosphate Na/Ca (AMP‐Na/Ca) on blood chemistry and nonspecific immune response of red sea bream juveniles. Test diets with three levels of AsA (free, 107, and 325 mg/kg diet) were fed to juvenile red sea bream (36.0 ± 1.3 g) two times a day for 3 wk. There were no significant differences in hematocrit, glucose, and blood urea nitrogen. Total cholesterol and triglyceride in plasma of fish fed AsA‐free diet was significantly (P < 0.05) higher than that of fish fed two other diets. There were no significant differences in serum albumin, total bilirubin, and total serum protein. Glutamyl oxaloacetic transaminase in serum of fish fed diets containing 107 and 325 mg of AsA were significantly (P < 0.05) lower than that of fish fed AsA‐free diet. Serum lysozyme activity (LA) of fish fed diets containing 107 and 325 mg of AsA were significantly (P < 0.05) higher than that of fish fed AsA‐free diet. There was no significant difference in mucus LA. The results mentioned above demonstrated that AMP‐Na/Ca is a bioavailable AsA source for red sea bream juveniles. Supplement of more than 107 mg AsA/kg in diets improved blood chemistry and nonspecific immune function of red sea bream juveniles.     

Liquid chromatographic determination of barbaloin (aloin) in foods

A simple and rapid liquid chromatographic method is described for the determination of barbaloin (aloin, 10-D-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthraceno ne) in foods. Barbaloin is extracted with water from foods containing aloe and the extract is cleaned up on a disposable cartridge by using methanol-water (55 + 45) as eluant. The eluted barbaloin is separated by liquid chromatography on a YMC A-302 column with methanol-water (50 + 50) mobile phase, and detected at 293 nm. Recoveries of barbaloin added to foods at the levels of 0.05 and 0.50 mg/g were 94.4-100%. Assay results for commercial food samples indicated that the present method is applicable to a variety of foods supplemented with aloe.     

Can fermented soybean meal and squid by‐product blend be used as fishmeal replacements for Japanese flounder (Paralichthys olivaceus)?

An experiment was carried out to evaluate fermented soybean meal and squid by‐product blend (1:1) (FP) as replacement of fishmeal (FM) for Japanese flounder, Paralichthys olivaceus. Five isocaloric (19 kJ g^?1) diets were prepared by replacing 0 (FP0), 12 (FP12), 24 (FP24), 36 (FP36) and 48% (FP48) FM protein with FP. Triplicate groups of juveniles (mean weight of 3.9 g) were delivered the test diets for 8 weeks in a flow‐through sea water system. The results showed that there were no significant differences (P > 0.05) among the growth rates of fish fed FP0, FP12, FP24 and FP36 diets. Growth and nutrient utilization parameters were significantly reduced in fish fed FP48 diet. Although, whole body proximate composition of fish were not significantly affected by the dietary treatments compared to the control; methionine and phenylalanine contents were significantly decreased in FP48 group. Protein retention was also significantly decreased in the similar group of fish. Dietary treatments did not alter most of the plasma metabolites, while some of the health parameters were improved in the replacement groups. Results suggested that FP is a potential candidate for alternative protein ingredient in aquafeed and can replace 36% FM protein in the diet of Japanese flounder.     

Utilization of monounsaturated fatty acid (18:1n-9, oleic acid) by freshwater prawn Macrobrachium rosenbergii (de Man) juveniles

The utilization of oleic acid as an energy source and the effects of oleic acid levels and/or dietary soy bean lecithin (SBL) on oleic acid utilization, growth and survival, and lipid class and fatty acid compositions of freshwater prawn, Macrobrachium rosenbergii (de Man), juveniles were determined.
Increase in levels of dietary oleic acid from 10 to 80 g kg⁻¹ significantly ( P ≤ 0.05) reduced growth, survival and feed conversion efficiency of M. rosenbergii juveniles during the 40-day feeding period. Inclusion of 20 g kg⁻¹ SBL had no significant effect ( P ≥ 0.05) on growth and survival, nor was there any interactive effect between dietary SBL and oleic acid levels.
Body fatty acid profile of prawns reflected dietary fatty acid quantity. The fatty acid composition of prawns fed diets containing 80 g kg⁻¹ oleic acid had tremendously high proportions of oleic acid. Polar lipids, mostly phosphatidylcholine (PC), constituted the bulk of the extracted total lipids. Prawns fed with SBL had significantly ( P ≥ 0.05) higher PC content.
Oleic acid was metabolized for energy by M. rosenbergii juveniles at the same rate regardless of dietary level of SBL and/or oleic acid. Expired ¹⁴CO₂ accounted for half of the ingested radioactivity 48 h after feeding with labelled diets. No significant difference in the amount of ¹⁴CO₂ expired by prawns fed the labelled test diets was found. Per cent radioactivity ingested and absorbed into the body was also not significantly different in prawns of the different dietary treatments.