BackgroundFatty acids synthesized in chloroplast are transported to endoplasmic reticulum (ER) for triacylglycerols (TAGs) resembling. The development of chloroplast also requires lipids trafficking from ER to chloroplast. The membrane contact sites (MCSs) between ER and chloroplast has been demonstrated to be involved for the trafficking of lipids and proteins. Lipids trafficking between ER and chloroplast is often accompanied by lipids interconversion. However, it is rarely known how lipids interconversion happens during their trafficking.Methodology/Principal FindingsWe cloned a lipase gene from Brassica napus L., designated as BnCLIP1. Green fluorescence protein (GFP)-tagged BnCLIP1 was shown to locate at the MCSs between ER and chloroplasts in tobacco leaves. Heterogeneous expression of BnCLIP1 in Saccharomyces cerevisiae (pep4) reduced the total amount of fatty acid. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the truncated BnCLIP1 had a substrate preference for C16:0 lipids in Saccharomyces cerevisiae (pep4). To probe the physiological function of BnCLIP1, two Brassica napus lines with different oil-content were introduced to investigate the transcript patterns of BnCLIP1 during seed development. Intriguingly, the transcript level of BnCLIP1 was found to be immediately up-regulated during the natural seed senescence of both lines; the transcription response of BnCLIP1 in the high oil-content seeds was faster than the lower ones, suggesting a potential role of BnCLIP1 in affecting seed oil synthesis via regulating chloroplast integrity. Further researches showed that chemical disruption of leaf chloroplast also activated the transcription of BnCLIP1.Conclusions/SignificanceThe findings of this study show that BnCLIP1 encodes a lipase, localizes at the MCSs and involves in chloroplast development.
The aim of the present study was to detect adulteration of canola oil with other vegetable oils such as sunflower, soybean, and peanut oils and to build models for predicting the content of adulterant oil in canola oil. In this work, 147 adulterated samples were detected by gas chromatography-ion mobility spectrometry (GC-IMS) and chemometric analysis, and two methods of feature extraction, histogram of oriented gradient (HOG) and multiway principal component analysis (MPCA), were combined to pretreat the data set. The results evaluated by canonical discriminant analysis (CDA) algorithm indicated that the HOG-MPCA-CDA model was feasible to discriminate the canola oil adulterated with other oils and to precisely classify different levels of each adulterant oil. Partial least square analysis (PLS) was used to build prediction models for adulterant oil level in canola oil. The model built by PLS was proven to be effective and precise for predicting adulteration with good regression (R2>0.95) and low errors (RMSE ≤ 3.23).
Changes in white shrimp () protein during thermal denaturation were studied using Raman spectroscopy and isotopic H/D exchange. Denaturation of shrimp protein began after heating for 10 min at 50°C. A decrease in the percentage of α-helices accompanied by an increase in the percentage of β-sheets occurred while the total percentage of disordered structures increased. With extension of the exchange time, the relative intensity of the O-D bond increased, accompanied by a higher relative O-D bond intensity for heated shrimp, compared with unheated shrimp. H/D exchange revealed a higher rate of deuteration kinetics in heated shrimp than for unheated shrimp, especially during the first 2 h, consistent with water loss from denatured white shrimp protein. Physical property changes in muscle tissue can be caused by changes in hydrogen bonding and hydrophobicity during thermal processes.
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