This study was conducted to investigate the effects of fishmeal replacement with acid-concentrated soybean meal (ACSBM) on growth performance, blood biochemistry, and ingredient digestibility in juvenile olive flounder Para-lichthys olivaceus. Six experimental diets were formulated to replace fishmeal protein with ACSBM at 0%, 20%, 30%, 40%, 50%, and 60% (designated ACSBM0, ACSBM20, ACSBM30, ACSBM40, ACSBM50, and ACSBM60, respectively). Triplicate groups of fish (initial fish mean weight: 14.3±0.03 g) were fed the experimental diets to apparent satiation (twice daily at 08:00 and 18:00 h). After a 12-week feeding trial, a total of 180 healthy fish were randomly distributed into three Guelph system tanks at a density of 60 fish/tank (initial fish mean weight : 50.6±2.4 g) to test the apparent digestibility coefficients of the ingredients (ACSBM, fishmeal, and soybean meal). Although negative effects were observed with ACSBM40, ACSBM50 and ACSBM60 after 12 weeks of feeding, up to 20% of the fishmeal protein could be successfully replaced with ACSBM without significant growth depression. Hemoglobin and hematocrit values of fish fed the ACSBM50 and ACSBM60 diets were significantly lower than those of fish fed the ACSBM0 diet. Glucose values of fish fed the ACSBM60 diet were significantly higher than those of fish fed the ACSBM0 and ACSBM20 diets. Digestibility of protein in ACSBM and soybean meal was 85.9% and 82.5%, respec -tively. Results indicated that at least 20% of fishmeal protein can be replaced by ACSBM in diets of juvenile olive flounder without supplementation of limiting amino acids. Key words: Olive flounder, Fish meal, Acid-concentrated soybean meal, Digestibility, Replacement
The 26S proteasome, composed of the 20S core and the 19S regulatory complex, plays a central role in ubiquitin-dependent proteolysis by catalyzing degradation of polyubiquitinated proteins. In a search for proteins involved in regulation of the proteasome, we affinity purified the 19S regulatory complex from HeLa cells and identified a novel protein of 43 kDa in size as an associated protein. Immunoprecipitation analyses suggested that this protein specifically interacted with the proteasomal ATPases. Hence the protein was named proteasomal ATPase-associated factor 1 (PAAF1). Immunoaffinity purification of PAAF1 confirmed its interaction with the 19S regulatory complex and further showed that the 19S regulatory complex bound with PAAF1 was not stably associated with the 20S core. Overexpression of PAAF1 in HeLa cells decreased the level of the 20S core associated with the 19S complex in a dose-dependent fashion, suggesting that PAAF1 binding to proteasomal ATPases inhibited the assembly of the 26S proteasome. Proteasomal degradation assays using reporters based on green fluorescent protein revealed that overexpression of PAAF1 inhibited the proteasome activity in vivo. Furthermore, the suppression of PAAF1 expression that is mediated by small inhibitory RNA enhanced the proteasome activity. These results suggest that PAAF1 functions as a negative regulator of the proteasome by controlling the assembly/disassembly of the proteasome.
The removal of fruit cluster leaves was shown to be a valuable method for controlling fruit quality and producing high-grade apples. A chemical defoliant that functions as an activation switch was shown to turn on the genes necessary for fruit cluster leaf defoliation. Elucidating the mechanism involved in leaf defoliation is crucial to our understanding of the use of chemical defoliants in fruit trees. To gain insight into chemical defoliant-mediated leaf defoliation, we first confirmed the occurrence of ethylene production by applying a chemical defoliant on fruit cluster leaves. Then, we used RNA-seq analysis to obtain a series of transcriptome profiles for genes and proteins involved in leaf senescence induction. Within 2 days of applying the chemical defoliant to apple trees, 1-aminocyclopropane carboxylic acid (ACC) oxidase, ACC synthase, a chlorophyll binding protein, and polygalacturonase-related genes were up-regulated at least sixfold. An in vitro enzyme assay showed that lanolin oil activates ACC synthase activity, a key regulatory enzyme in the ethylene pathway. We also showed that chemical defoliant decreased the light saturation point and total chlorophyll content. Then, we used a polygalacturonase activity assay to confirm the effects of chemical defoliant on leaf senescence in vivo. Furthermore, treatment with chemical defoliant resulted in a significant increase in the chromaticity value of a*, whereas L* and b* decreased in the apple fruit. Taken together, we conclude that chemical defoliant could selectively affect fruit cluster leaves, which suggested that it can be used as a selective defoliant.
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