Resistance index and browning mechanism of apple peel under high temperature stress

Apples are one of the most important economic crops worldwide.Because of global warming and an aggravation of environmental,abnormally high temperatures occur frequently in fruit-growing season and seriously affect normal fruit growth and reduce fruit quality and yield.We took five-year-old Ruixue’(Qinfu 1×Pink Lady;CNA20151469.1) fruits as test materials,and the ambient temperature during fruit development was monitored.The results showed that during the fruit-growing season,especially during the rapid growth stage (July to August),the maximum daily temperature exceeded 30℃ and lasted for more than 40 days.To determine the effects of high temperature stress on the apple fruit resistance,we treated expanding,veraison,and maturity-period fruits at different temperatures.It was found that the fruits of the expanding period showed strong resistance to high temperature stress,whereas during veraison and maturity,fruit resistance to high temperature stress decreased,and the fruit peel browning phenotype appeared.Meanwhile,the content of malonaldehyde (MDA),hydrogen peroxide (H_(2)O_(2)),and superoxide anion (O._(2)^(-)) in the peel gradually increased with increasing temperature.The content of total phenols,flavanol,and flavonoids in the peel decreased substantially at 45℃.Moreover,it was found that polyphenol oxidase gene (MdPPO1) was most sensitive to high temperature stress in apple.Furthermore,transient and stable MdPPO1 overexpression significantly promoted peel browning.The transgenic materials were more sensitive to high temperatures,and browning was more severe compared to non-genetically modified organism (WT).Stable MdPPO1 knockout calli obtained via clustered regularly interspersed short palindromic repeats (CRISPR/Cas9) gene knockout technology reduced the browning phenotype,and the resultant fruits were not sensitive to the effects of high temperature stress.Thus,MdPPO1 expression may be a key factor of high temperature-related changes observed in the browning phenotype that provides a scientific theoretical basis for the selection of high temperature-resistant varieties and apple cultivation and management in the future.

Comparative histology,transcriptome,and metabolite profi ling unravel the browning mechanisms of calli derived from ginkgo(Ginkgo biloba L.)

Gingko biloba accumulates high levels of secondary metabolites of pharmaceutical value.Ginkgo calli develop a typical browning that reduces its regenerative capacity and thus its usefulness.To elucidate the browning mechanism,histological,transcriptomic,and metabolic alterations were compared between green and browning calli derived from immature ginkgo embryos.Histological observations revealed that browning calli had a more loosely arranged cell structure and accumulated more tannins than in green calli.Integrated metabolic and transcriptomic analyses showed that phenylpropanoid metabolism was specifi-cally activated in the browning calli,and 428 diff erentially expressed genes and 63 diff erentially abundant metabolites,including 12 fl avonoid compounds,were identifi ed in the browning calli compared to the green calli.Moreover,the expression of fl avonol synthase(FLS)and UDP-glucuronosyl-transferase(UGT)genes involved in the fl avonoid pathway was more than tenfold higher in browning calli than in green calli,thus promoting biosynthesis of fl avonol,which serves as a substrate to form glycosylated fl avonoids.Flavonoid glycosides constituted the major coloring component of the browning calli and may act in response to multiple stress conditions to delay cell death caused by browning.Our results revealed the cellular and biochemical changes in browning callus cells that accompanied changes in expression of browning-related genes,providing a scientifi c basis for improving ginkgo tissue culturability.

Widely Untargeted Metabolome Profiling Provides Insight into Browning and Nutritional Quality Changes in Short-Term Stored Fresh-Cut Potato(Solanum tuberosum L.)Shreds

Potato(Solanum tuberosum L.)is susceptible to enzymatic browning after fresh processing,resulting in color change and potential alteration in the nutritional quality.In this study,a popular potato cultivar,Feiwuruita,was used to profile the metabolites involved in color and nutritional quality changes in fresh shreds stored at 0 and 4 h at 25°C(designated CK and CK4H,respectively).The shreds turned brown within 4 h of storage.In all,723 metabolites consisting 12 classes of compounds were detected in the samples,largely lipids,phenolic acids,alkaloids,amino acids and derivatives,flavonoids,organic acids,nucleotides and derivatives.Of these,163 metabolites accumulated differentially between CK and CK4H shreds.Polyphenolic compounds(phenolic acids and flavonoids)mostly increased in the shreds after 4 h storage.Conversely,the short-term storage drastically reduced lipid compounds(25 LysoPC and 19 LysoPE),while essential alkaloids and terpenoid compounds that are beneficial to human health increased in accumulation.The findings present global metabolome and nutritional composition changes in short-term stored shreds of Feiwuruita.This study provides important foundation for future studies on browning prevention/reduction and for better utilization of Feiwuruita.

Ginsenoside F1 administration promotes UCP1-dependent fat browning and ameliorates obesity-associated insulin resistance

Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.

AcbHLH144 transcription factor negatively regulates phenolic biosynthesis to modulate pineapple internal browning

Internal browning(IB),a major physiological disorder of pineapples,usually happens in postharvest processes,but the underlying mechanism remains elusive.The bHLH transcription factors are involved in regulating various biological processes,but whether they could regulate tissue browning in fruit during storage remains unknown.Here we showed that the phenolic biosynthesis pathway was activated in pineapples showing IB following 9 days of storage.AcbHLH144 expression was the highest of the 180 transcription factors identified,downregulated in pineapple with IB,and negatively correlated with the major phenolic biosynthetic genes.AcbHLH144 was shown to be localized in the nucleus and its transient overexpression in pineapples and overexpression in Arabidopsis decreased phenolic biosynthesis.The yeast one-hybrid assay and electrophoretic mobility shift assay showed that AcbHLH144 directly bound to the Ac4CL5 promoter and the dual-luciferase reporter assay showed that it inactivated Ac4CL5 transcription.These results strongly suggest AcbHLH144 as a repressor for phenolic biosynthesis.Abscisic acid(ABA)alleviated IB,reduced phenolic accumulation,and downregulated phenolic biosynthetic genes,including Ac4CL5.Transcriptomic analysis showed that AcbHLH144 was the most upregulated of all 39 bHLHs in response to ABA.ABA enhanced AcbHLH144 expression,reduced phenolic contents,and downregulated phenolic biosynthetic genes in pineapples transiently overexpressing AcbHLH144.Moreover,ABA enhanced enzyme activity of GUS driven by the AcbHLH144 promoter.These results showed that AcbHLH144 as a repressor for phenolic biosynthesis could be activated by ABA.Collectively,the work demonstrated that AcbHLH144 negatively regulated phenolic biosynthesis via inactivating Ac4CL5 transcription to modulate pineapple IB.The findings provide novel insight into the role of AcbHLH144 in modulating pineapple IB during postharvest processes.

On the Dramatic Features in Robert Browning's Poems of Dramatic Monologue

This paper explored the three dramatic features intrinsic in Robert Browning's poems of dramatic monologue, namely, the employment of first-person point of view, the use of irony, and the intricate psychological exploration and vivid characterization. Such features are crucial in the successful presentation of various human nature and experience with profundity, making his poems an enduring classic in the English literature.

Polyphenolic Compound and the Degree of Browning in Processing Apple Varieties

Polyphenolic compound in processing apple （Malus domestica Borkh.） varieties and the relationship between polyphenol content and enzymatic browning were studied to provide reference for raw material selection and processing method optimization. The content of polyphenol compound in 10 processing apple varieties （4 cider and 6 juice varieties） were analyzed using the Folin-Ciocalteu method and HPLC. The degree of browning and the activities of polyphenol oxidase were also studied. The content and proportion of the polyphenol varied depending on the variety. Bitter varieties globally showed a higher polyphenol concentration than sweet or acid varieties. Proanthocyanidins, chlorogenic acid, （＋）-catechin, （-）-epicatechin were high-concentrated polyphenols in apple fruits. Phloridzin, the unique polyphenol of apple, was abundant in the bitter variety Frequin rouge fruit. Total polyphenols, proanthocyanidins, （＋）-catechin, and phloridzin had higher correlations with browning. The correlation was low between chlorogenic acid and browning. The polyphenolic profiles were correlated with the apple types. Cider apples contained more polyphenol than juice apple varieties. The content of flavan-3-ol has a close relationship with fruit browning.

Study on the Mechanism of Browning of Pomegranate (Punica granatum L.cv.Ganesh) Peel in Different Storage Conditions

Peel browning of pomegranate fruit is the key problem during storage. The mechanism of it during storage in relation to the technology of the browning control was studied in this paper. The effects of storage temperature, gas component and pH value on peel browning of sweet pomegranate fruit in Lintong, Shaanxi Province, China, were investigated. Change in tannin content was measured and the relationship between the activities of ascorbic acid oxidase （AAO）, polypenoloxidase （PPO）, peroxidase （POD）, catalase （CAT） and peel browning was analysed. The results showed tannin was the basic substance of pomegranate peel browning. The activities of the browning index of peel were correlated positively with AAO, PPO and POD, correlated negatively with CAT activity. Application of intermittent warming for 24 h at （15 ± 0.5）℃ every 5 days for pomegranate fruit storage under the conditions of pH 4.0, （5.0± 0.5）℃ and 5.0% CO2 ＋ 8.0% O2 ＋ 87.0% N2 gas component could delay browning, with the browning index being 0.15 after 120 days of storage. Enzymatic tannin denaturation was the main cause that led to peel browning of pomegranate fruit during storage. The browning control of pomegranate fruit peel was effective using intermittent warming storage with suitable pH, temperature and gas component.

Postharvest Low Temperature Conditioning Reduces Peel Browning and Improves Fruit Quality in Storage and Subsequent Shelf Life of Huangguan Pear

Huangguan pear (Pyrus bretschneideri Rehd cv. Huangguan) is a pear cultivar that rapidly developed in China. However, rapid postharvest browning appearing in fruit peel and core during storage and shelf life pose a challenge for their marketing. The potential for low temperature conditioning (LTC) treatment to inhibit peel browning and improve quality of Huangguan pears in storage and shelf life was investigated. Pears were treated at 8℃ - 9℃ for 1, 3, 6 and 9 d, respectively, physiological indexes, including peel and core browning, core breakdown, malondialdehyde (MDA) content and ethanol content were determined and quality in storage period and shelf life was evaluated in this paper. LTC treatment alleviated peel browning and core browning either in storage or shelf life remarkably;it also delayed the decline of firmness, total soluble solids and titratable acidity in storage to some extent, inhibited ethanol and MDA content both in storage and shelf life effectively and maintained juiciness and crispness of pear fruit in shelf life. These results showed that LTC can serve as an important tool for the regulation of Huangguan pears external and internal quality in storage and shelf life with economic benefits and LTC treatment for 6 d was the optimum condition in the present study.

Contamination and browning in tissue culture of Platanus occidentalis L.

Twigs of 2-3-year-old Platanus occidentalis L. were used as experimental material to find the causes for the contamination and browning in the initial stages of tissue cultures. To compare the degree of browning of explants picked off from different growing seasons, the experimental material was excised from trees on each of the first ten days in January, March, May and July, 2006. The results indicated that the contamination and browning rates of the material cut off in January （14.2% and 30.6%, respectively） and March were somewhat lower than those in July. The pretreatment of soaking the explants in different anti-oxidants and absorbents at the same time could diminish some side effects. The pretreatment of using 10 g·L^-1 vitamin C reduced the contamination and brown- ing rate effectively. An orthogonal experiment showed that the optimal factor and level arrangement is 0.5 mg·L^-1BA, 2.0 g·L^-1 active carbon and 1.5 g·L^-1 PVP which resulted in a browning rate of only 16.5%. In general, sampling period, physical properties and pretreatment of explants are the main factors responsible for the contamination and browning of material in the initial stages of P. occidentalis tissue cultures.

Effects of grape seed extract on meat color and premature browning of meat patties in high-oxygen packaging

This study investigated the effects of grape seed extract(GSE)on fresh and cooked meat color and premature browning(PMB)in ground meat patties(85% beef and 15% pork back fat)packaged under high-oxygen modified atmospheres(HiOx-MAP).The GSE was added to patties at concentrations of 0,0.10,0.25,0.50 and 0.75 g kg^(-1).This study evaluated the surface color,pH,lipid oxidation,and total viable counts(TVC)of raw patties,and the internal color and pH of patties cooked to a temperature of 66 or 71℃ over 10-day storage at 4℃.Compared with the control(0 g kg^(-1) GSE),GSE improved the color stability(P<0.05)and significantly inhibited the lipid and myoglobin oxidation of raw patties from day 5 to 10,but GSE had no effect(P>0.05)on TVC.Patties containing 0.50 and 0.75 g kg^(-1) GSE cooked to 66℃ exhibited greater(P<0.05)interior redness than the control and reduced the PMB of cooked patties in the late storage stage.These results suggested that 0.50 and 0.75 g kg^(-1) GSE can improve fresh meat color and minimize PMB of HiOx-MAP patties.

Phenolic Profiles and Polyphenol Oxidase (PPO) Gene Expression of Red Clover (Trifolium pratense) Selected for Decreased Postharvest Browning

Red clover (Trifolium pratense L.) is a legume forage abundant in phenolic compounds. It tends to brown when cut for hay, due to oxidation of phenolic compounds catalyzed by polyphenol oxidase (PPO), and subsequent binding to proteins. Selecting for a greener hay may provide information about the relationship of browning, PPO, and phenolics to each other. The red clover Kenland cultivar was selected over eight breeding cycles for decreased browning after being cut and dried 48 h in the field. Expression of PPO1 and PPO3, in Kenland and three of the eight cycles, was compared by real-time quantitative PCR. Phenolic compounds in Kenland and Cycle 8, collected 0, 24, and 48 h after cutting, were quantified by high-performance liquid chromatography (HPLC). Visual browning scores decreased 12% between Kenland and Cycle 8 (P = 0.02). PPO1 and PPO3 gene expression were not affected by selection. Clovamide decreased 26% in Cycle 8 relative to Kenland (P = 0.016). Sissotrin decreased 10% in Cycle 8 (P = 0.043). Neither total formononetin nor total biochanin A was affected by selection (P = 0.63 and 0.45, respectively). These results suggest that when selecting clover for decreased postharvest browning, a decrease occurs in a phenolic compound that can bind protein independently of PPO. However, PPO1 and PPO3 gene expression, and the major red clover isoflavones, are minimally affected.

Inhibitive effects of some treatments on the browning rate during the in vitro culture of Acacia karroo Hayne

Acacia karroo Hayne is an arbor species widely distributed in South Africa with the characteristics of fast growth and drought resistance. The species was introduced to China recently. In vitro culture is an effective method to rapidly produce plants and a strategy to minimize somaclonal variation among regenerated plants. Browning, however, is a problem in establishing the in vitro culture system. The present study diminished the problem by selecting explants, using different browning inhibitors and chilling treatment. Results showed that the use of embryos as explants reduced the browning ratio to 46.7%, whilst stem segment explants were browned up to 56.7%. The adventitious buds were successfully induced in the modified tissue culture medium supplemented with 5.0 mg·L^-1 6-BA and 0.1 mg·L^-1 NAA. The proliferation coefficient of adventitious buds is 2.8.

Ginsenoside rg3 reduces body weight by regulating fat content and browning in obese mice

Objective:To determine the effects of ginsenoside rg3 on the body weight of C57BL/6J obese mice and to investigate its underlying weight loss mechanisms with a focus on white fat browning-related factors.Methods:Eight-week-old C57BL/6J male mice were fed a high-fat diet for 12 successive weeks to construct the obese model.C57BL/6J male mice were fed a standard chow diet to construct normal control group.After 8 weeks of intervention with ginsenoside rg3,the food intake,body weight,body fat mass,blood sugar,and lipid profiles of the mice in each group were detected.Hematoxylin and eosin(HE)staining was used to observe the histological morphology of the adipose tissues.Real-time polymerase chain reaction(RT-PCR)and Western blotting(WB)were applied to detect the gene and protein expression levels of peroxisome proliferators-activated receptor gama(PPARg),Peroxisome proliferatoractivated receptor-gamma coactivator-1alpha(PGC-1a),PR domain containing 16(PRDM16),and uncoupling protein 1(UCP-1).Results:Compared to normal control group mice,the body weight,food intake,body fat composition,and blood lipid levels of model group mice increased significantly.After 8 weeks of intervention with ginsenoside rg3,body weight,body fat composition,food intake,and blood lipid profiles decreased.HE staining showed that ginsenoside rg3 can improve white adipocyte hypertrophy to a certain extent.RTPCR and WB demonstrated that ginsenoside rg3 can increase the mRNA and protein expression levels of PPARg,PGC-1a,PRDM16,and UCP-1 in the adipose tissues of obese mice.Conclusion:The weight reduction effect of ginsenoside rg3 may be related to the promotion of white fat browning.

The Effect of Different Chemical Agents on the Prevention of Enzymatic Browning in Banana

This study was conducted to test the concept of fresh cut banana slices with the effects of chemical treatments on the surface appearance and selected quality indexes of banana samples right after cutting and during 2-week of storage at refrigeration conditions(0-4°C).Banana slices were treated with an ascorbic acid,sodium chloride,citric acid,calcium chloride,and sodium carbonate,water(room temperature),and hot water(65°C).Quality attributes,e.g.color,PPO(polyphenol oxidase)activities,surface appearance of the cut bananas were compared.Banana slices immersed in sodium chloride,calcium chloride,citric acid and sodium ascorbate showed visual traces of browning during storage at 4°C.After 14 days of storage,only ascorbic acid treated banana samples showed moderate browning,while all other treatments were severely affected.Browning was more severe for the samples immersed in water for all storage times.The browning measurement(a value)became increasingly positive from first to fourteenth day storage.It was observed that the inactivation of PPO enzyme was achieved for the ascorbic acid treated sample most.Rather than ascorbic acid treatment,cut banana samples showed less PPO enzyme activity for sodium chloride,citric acid,calcium chloride,sodium carbonate,hot water,and water(room temperature)treatments,subsequently.There were no significant changes observed on the different chemical treatments(sodium chloride,citric acid,calcium chloride,and sodium carbonate)except ascorbic acid.In overall,ascorbic acid was found to be the most efficient treatment on the inactivation of PPO enzyme activity among all the treatments.Beside the inactivation of the enzyme,ascorbic acid showed a better success to prevent color degradation of bananas.This study showed that ascorbic acid treatment is an effective chemical agent on the inactivation of browning enzymes.

Effect of Postharvest Heat Treatment on Pear Browning during Storage

The effect of postharvest heat treatment on browning of Huangguan pear was investigated. The results showed that heat treatment improved hardness and soluble solid content of stored pear fruit, postponed the improvement of MDA content and PPO activity in stored pear fruit and alleviated the reduction of SOD activity and the lowering of PG activity. To sum up, heat treatment reduces the occurrence of browning of stored pear fruit through the regulation of the changes in a series of physiological and biochemical indexes of fruit.

Study on the Effect of Enzymolysis Condition on the Browning of Chinese Chestnut Serosity

In this study,with chestnut as a raw material,the effects of enzymolysis time,enzymolysis temperature and enzyme amount on hydrolysis process were investigated. The optimal reaction conditions were obtained by single factor and response surface experiment as follows： enzymolysis time of 75 min,enzymolysis temperature at 58 ℃ and enzyme amount of 7 U/g. Under these conditions,the browning degree of chestnut serosity was 1. 228.

White Fat tissue’s Browning:Gaps in Knowledge and Current Clinical Significance

There are three types of fat tissue in mammals:white fat tissue(WAT),classic brown fat tissue(cBAT),and inducible brown fat tissue(iBAT)or beige fat tissue.The brown fat tissue in the human body is more similar to the induced brown fat tissue in mice.The main function of WAT is to store energy in the form of triacylglycerols and to regulate endocrine function.The main function of cBAT and iBAT is to generate heat and maintain the energy balance of the body.A cold environment and exercise can stimulate the browning of white fat tissue.The browning of white fat tissue is a complex process involving many factors,with PRDM16,PPARγand PGC-1αbeing the core transcription factors related to the process.Previous studies showed that white adipose browning is beneficial for the treatment of obesity,diabetes,fatty liver and other diseases.On the other hand,it can promote the progression of malignant tumors.Under normal conditions,the different types of fat tissue maintain a dynamic balance in the human body.Therefore,obtaining a better understanding of this balance and determining how to intervene at the early stages of metabolic imbalance are necessary.

关于核准Mark Browning担任邓普顿国际股份有限公司北京代表处首席代表的批复

2009年10月10日证监许可[2009]1063号邓普顿国际股份有限公司:你公司报送的关于更换北京代表处首席代表的申请及相关文件收悉。根据《证券法》、《外国证券类机构驻华代表机构管理办法》(证监机构字[1999]26号)等有关规定,

White adipose tissue browning and obesity

Obesity and metabolic disorders are major health concems worldwide. Although a range of therapies have been developed, these pharmaceutical treatments often have adverse side effects or limited efficacy. Therefore, there is a growing need of novel therapeutics to prevent or treat obesity. Obesity is thought to be caused by an imbalance between energy intake and energy consumption. Increasing energy consumption is considered as a potential therapeutic strategy to treat obesity and its related disorders.