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Yang He Xiulian Guo Ran Lu Bei Niu Vijaya Pasapula Pei Hou Feng Cai Ying Xu Fang Chen 《Plant Cell, Tissue and Organ Culture》2009,98(1):11-17
Callus browning is a typical feature of callus cultures derived from the hypocotyl of Jatropha curcas. Brown callus results in decreased regenerative ability, poor growth and even death. In this study, we investigated the effect
of browning on callus morphology and biochemical indices. Light microscopy and scanning electron microscopy showed striking
differences in callus morphology. During browning, chlorophylls and carotenoids concentrations decreased steadily. Polyphenol
oxidase (PPO) and peroxidase (POD) enzymatic activities patterns were similar during callus culture with a higher activity
level at week 3 compared to week 2 or later weeks. Grey relation degree analysis indicated that PPO played a more important
role than POD in enzymatic callus browning. Polyacrylamide gel electrophoresis results showed differences between browning
and non-browning callus. Gas chromatography–mass spectrometry results showed that saturated and unsaturated fatty acid quantities
differed significantly but there was little difference in fatty acid composition between non-browning and browning callus.
Differences in 17, 18.4 and 25 kDa protein concentrations were also observed in browning and non-browning callus using sodium
dodecyl sulfate–polyacrylamide gel electrophoresis. 相似文献
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Browning of chitooligomers and their optimum preservation 总被引:1,自引:0,他引:1
Lintao Zeng Caiqin Qin Weilin Chi Liansheng Wang Zongjun Ku Wei Li 《Carbohydrate polymers》2007,67(4):551-558
Chitooligomers have attracted much interest due to their unique biological activities. However, chitooligomers easily turn brown during shelf life. The factors influencing the browning of chitooligomers were investigated. The results indicated that the browning was attributed to the structure change of chitooligomers. The water-solubility, thermal stability and moisture–adsorption of chitooligomers decreased with the increase of browning. The time, temperature, pH, moisture, oxygen and reductant all had effect on the browning of chitooligomers. The optimal preservation condition for chitooligomers should be at low temperature and humidity, at pH below 4 or above 10, and in absence of oxygen. 相似文献
4.
Adipose tissue is a major metabolic organ, and it has been traditionally classified as either white adipose tissue(WAT) or brown adipose tissue(BAT). WAT and BAT are characterized by different anatomical locations, morphological structures, functions, and regulations. WAT and BAT are both involved in energy balance. WAT is mainly involved in the storage and mobilization of energy in the form of triglycerides, whereas BAT specializes in dissipating energy as heat during cold- or diet-induced thermogenesis. Recently, brownlike adipocytes were discovered in WAT. These brownlike adipocytes that appear in WAT are called beige or brite adipocytes. Interestingly, these beige/brite cells resemble white fat cells in the basal state, but they respond to thermogenic stimuli with increased levels of thermogenic genes and increased respiration rates. In addition, beige/brite cells have a gene expressionpattern distinct from that of either white or brown fat cells. The current epidemic of obesity has increased the interest in studying adipocyte formation(adipogenesis), especially in beige/brite cells. This review summarizes the developmental process of adipose tissues that originate from the mesenchymal stem cells and the features of these three different types of adipocytes. 相似文献
5.
The effect of sugar,amino acid,metal ion,and NaCl on model Maillard reaction under pH control 总被引:3,自引:0,他引:3
Summary. The color intensities was determined of Maillard reaction products (MRPs) prepared by heating each of five sugars (maltose, fructose, glucose, arabinose, and xylose) with each of 12 amino acids (aspartic acid, glutamic acid, alanine, leucine, isoleucine, valine, proline, serine, cysteine, phenylalanine, arginine, and lysine). The remaining percentages of glucose and rate of change of color intensity due to the addition of a metal ion and NaCl were monitored for nine MRPs that had been formed between glucose and each of nine amino acids (aspartic acid, glutamic acid, alanine, valine, serine, cysteine, phenylalanine, arginine, and lysine). Model MRPs were prepared in a block heater at 100°C for 1–12h with the pH value controlled at 6.5. The resulting color intensity of each MRPs formed from the basic amino acids was greater due to the higher reactivity than those from the acidic amino acids. The remaining percentage of glucose in each MRPs from the basic amino acids was lower than those from the acidic amino acids. The MRPs from the nonpolar amino acids showed an intermediate color intensity and remaining percentages of glucose between those formed from the basic and acidic amino acids. Browning tended to be accelerated in the presence of metal ions, especially Fe2+ and Cu2+, although it was affected by the property of the amino acid and heating time as well as by the type of metal ion. On the other hand, browning was greatly inhibited by a high concentration of NaCl. 相似文献
6.
An in vitro propagation protocol has been developed from mature lianas of Bauhinia valii. Browning was the major obstacle in the establishment of cultures. Explants collected during the growing season (April–June)
showed maximum browning; however, browning was minimal during the dormant phase. This problem was circumvented by soaking
the sterilized explants in a solution of antioxidant (50 mg l–1 ascorbic acid+75 mg l–1 citric acid). The explants were thereafter transferred to culture room conditions after an initial incubation in the dark
at 4 °C for 48 h. Shoot proliferation (58%), shoot number (4.5) and shoot length (35 mm) was best in Murashige and Skoog (MS)
medium supplemented with 2.5 μM kinetin + 100 mg l–1 adenine sulfate. Seasonal fluctuations significantly affected the proliferation potential of the explants. March– April was
found to be the best season for shoot initiation. Microshoots were rooted on a half-strength, growth regulator-free, agar-gelled
Murashige and Skoog medium after a dip in half-strength MS liquid medium containing 1-naph-thaleneacetic acid + indole-3-butyric
acid (10 μM). Rooted plantlets were potted and acclimatized under culture room conditions for 4 weeks before transfer to a polyhouse.
Received: 9 March 1998 / Revision received: 14 August 1998 / Accepted: 23 September 1998 相似文献
7.
荔枝果实以10ppm的6-BA、NAA、GA_3 NAA或PVP(1%) NAA处理2min,1℃贮藏8天后再于室温放2天。EPR分析表明果皮的有机自由基(g因子2.0030)比对照低9%—22%,花色素苷含量高5%—46%。离体果皮小圆片经同法浸泡1h或16h,有机自由基反而比对照高。O_2~-的捕获剂Tiron和抗氧化剂PG CA处理果皮小圆片1h,有机自由基降低8%—11%,处理16h则自由基高于对照。邻苯二酚(pH 8.4)和H_2O_2加速果色变褐,有机自由基增高10%—370%。果皮离体后自由基的EPR波谱特征也发生变化,除了一个g因子2.0026—2.0027的主峰外,尚出现另一个小峰。结果表明荔枝果皮褐变的部分原因是有机自由基增高之故。 相似文献
8.
以雷公藤(Tripterygium wilfordii Hook f.)根愈伤组织为材料,以NT为基本培养基,添加不同浓度硫代硫酸钠、抗坏血酸、柠檬酸、硝酸银、聚乙烯吡咯烷酮以及活性炭,探讨抗褐变剂对雷公藤愈伤组织生长、抗褐化和雷公藤内酯醇及总生物碱含量的影响。结果表明:除较低浓度柠檬酸以外,其他抗褐变剂均不同程度抑制雷公藤愈伤组织的生长。培养基中添加不同浓度硫代硫酸钠、抗坏血酸、柠檬酸、聚乙烯吡咯烷酮以及活性炭,雷公藤愈伤组织褐化程度不但没有得到控制,反而使褐化加重。但所有处理中,愈伤组织中内酯醇含量明显升高,其中加入50mg/L柠檬酸处理的内酯醇含量为对照的2.4倍。培养基中加入10~50mg/L硝酸银不仅能抑制雷公藤愈伤组织褐变,内酯醇的含量也随着硝酸银浓度的增加而增加。供试抗褐变剂中除较低浓度硫代硫酸钠以外,其他处理对雷公藤总生物碱的合成起抑制作用。 相似文献
9.
Yan Xiong Feng Yue Zhihao Jia Yun Gao Wen Jin Keping Hu Yong Zhang Dahai Zhu Gongshe Yang Shihuan Kuang 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2018,1863(4):409-419
The thermogenic activities of brown and beige adipocytes can be exploited to reduce energy surplus and counteract obesity. Recent RNA sequencing studies have uncovered a number of long noncoding RNAs (lncRNAs) uniquely expressed in white and brown adipose tissues (WAT and BAT), but whether and how these lncRNAs function in adipogenesis remain largely unknown. Here, we report the identification of a novel brown adipocyte-enriched LncRNA (AK079912), and its nuclear localization, function and regulation. The expression of AK079912 increases during brown preadipocyte differentiation and in response to cold-stimulated browning of white adipocytes. Knockdown of AK079912 inhibits brown preadipocyte differentiation, manifested by reductions in lipid accumulation and down-regulation of adipogenic and BAT-specific genes. Conversely, ectopic expression of AK079912 in white preadipocytes up-regulates the expression of genes involved in thermogenesis. Mechanistically, inhibition of AK079912 reduces mitochondrial copy number and protein levels of mitochondria electron transport chain (ETC) complexes, whereas AK079912 overexpression increases the levels of ETC proteins. Lastly, reporter and pharmacological assays identify Pparγ as an upstream regulator of AK079912. These results provide new insights into the function of non-coding RNAs in brown adipogenesis and regulating browning of white adipocytes. 相似文献
10.
Summary. Glutamine is one of the most abundant free amino acid found in raw food. In this study, the contribution of free glutamine
to nonenzymatic browning and fluorescence was investigated using an aqueous model system with methylglyoxal. The results indicated
that glutamine contributed to the Maillard reaction via two pathways. First, the hydrolysis of the amide bond of glutamine
led to the release of ammonia which was implicated in the formation of brown color and fluorescence. Among other nitrogen
donors tested (asparagine, glutamic acid and urea) our results demonstrated that free glutamine was a major source of ammonia
during heating. When heated at 120 and 180 °C, 100% of ammonia was released from glutamine after 60 and 10 min, respectively.
The second pathway involved a direct Maillard reaction with the α-amino group of glutamine. Both pathways led to a rapid and
complete destruction of glutamine when heated in the model systems. With reference to the Maillard browning (absorbance at
420 nm) glutamine turned out to be the most reactive amine, followed by asparagine, glutamate, ammonia and urea. Maximum fluorescence
(excitation and emission wavelengths at 330 and 450 nm, respectively) was also observed with glutamine followed by urea and
ammonia. Overall this study suggested that free glutamine predominantly contributes to the color and fluorescence formations
of foodstuffs. 相似文献