Diversity of Sodium Transporter HKT1;5 in Genus Oryza

Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.

Changes in urinary excretion of water and sodium transporters during amiloride and bendroflumethiazide treatment

AIM： To quantify changes in urinary excretion of aquaporin2 water channels （u-AQP2）, the sodium-potassium-chloride co-transporter （u-NKCC2） and the epithelial sodium channels （u-ENaC） during treatment with bendrofumethiazide （BFTZ）, amiloride and placebo.METHODS： In a randomized, double-blinded, placebo-controlled, 3-way crossover study we examined 23 healthy subjects on a standardized diet and fuid intake. The subjects were treated with amiloride 5 mg, BFTZ 1.25 mg or placebo twice a day for 4.5 d before each examination day. On the examination day, glomerular filtration rate was measured by the constant infusion clearance technique with 51Cr-EDTA as reference substance. To estimate the changes in water transport via AQP2 and sodium transport via NKCC2 and ENaC, u-NKCC2, the gamma fraction of ENaC （u-ENaCγ）, and u-AQP2 were measured at baseline and after infusion with 3% hypertonic saline. U-NKCC2, u-ENaCγ, u-AQP2 and plasma concentrations of vasopressin （p-AVP）, renin （PRC）, angiotensin Ⅱ （p-ANG Ⅱ） and aldosterone （p-Aldo） were measured, by radioimmunoassay. Central blood pressure was estimated by applanation tonometry and body fuid volumes were estimated by bio-impedance spectroscopy. General linear model with repeated measures or related samples Friedman’s two-way analysis was used to compare differences. Post hoc Bonferroni correction was used for multiple comparisons of post infusion periods to baseline within each treatment group.RESULTS： At baseline there were no differences in u-NKCC2, u-ENaCγ and u-AQP2. PRC, p-Ang Ⅱ and p-Aldo were increased during active treatments （P 〈 0.001）. After hypertonic saline, u-NKCC2 increased during amiloride （6% ± 34%; P = 0.081） and increased significantly during placebo （17% ± 24%; P = 0.010）. U-AQP2 increased signifcantly during amiloride （31% ± 22%; P 〈 0.001） and placebo （34% ± 27%; P 〈 0.001）, while u-NKCC2 and u-AQP2 did not change signifcantly during BFTZ （-7% ± 28%; P = 0.257 and 5% ± 16%; P = 0.261）. U- ENaCγ increased in all three groups （ P 〈 0.050）. PRC, AngⅡ and p-Aldo decreased to the same extent, while AVP increased, but to a smaller degree during BFTZ （ P = 0.048）. cDBP decreased significantly during BFTZ （P 〈 0.001）, but not during amiloride or placebo. There were no significant differences in body fuid volumes.CONCLUSION： After hypertonic saline, u-NKCC2 and u-AQP2 increased during amiloride, but not during BFTZ. Lower p-AVP during BFTZ potentially caused less stimulation of NKCC2 and AQP2 and subsequent lower reabsorption of water and sodium.

Relationships of CDXs and apical sodium-dependent bile acid transporter in Barrett's esophagus

Barrett's esophagus (BE) is characterized by intestinal metaplasia with the differentiated epithelium replaced by another type of epithelium morphologically similar to normal intestinal epithelium. The metaplasia is preceded by bile and acid reflux into the esophagus. BE is a premalignant condition associated with increased risk of esophageal cancer, especially esophageal adenocarcinoma. The Caudal-related homeodomain transcription factors Caudal-related homeodomain transcription factor CDX1 and CDX2 are expressed exclusively in the small and large intestine, playing important roles in proliferation and differentiation of intestinal epithelial cells. Ectopic expression of CDX1 and CDX2 occurs in BE. The apical sodium-dependent bile acid transporter (ASBT) is expressed primarily in terminal ileum where it is a key factor for intestinal reabsorption of bile salts. In addition to upregulation of CDX1 and CDX2, ASBT expression is up-regulated in BE. Furthermore, both CDX1/CDX2 and ASBT expressions are down-regulated in high-grade esophageal dysplasia. The alteration of the above-mentioned factors calls for attention: what is the relationship between CDXs and ASBT aberrant expression in BE? In this commentary, we discuss this issue on basis of the recent study done by Ma et al .

Role of sodium-glucose co-transporter-2 inhibitors in the management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic liver disease worldwide. NAFLD is considerably more frequent in patients with type 2 diabetes mellitus (T2DM) than in the general population and is also more severe histologically in this group. Sodium-glucose co-transporter-2 (SGLT2) inhibitors, the newest class of antidiabetic agents, appear to represent a promising option for the management of NAFLD in patients with T2DM. In a number of studies, treatment with SGLT2 inhibitors resulted in a reduction in hepatic steatosis and in transaminase levels. However, existing studies are small, their follow-up period was short and none evaluated the effects of SGLT2 inhibitors on liver histology. Accordingly, larger studies are needed to verify these preliminary results and define the role of SGLT2 inhibitors in the treatment of NAFLD in patients with T2DM.

Analgesic effect of intrathecal bumetanide is accompanied by changes in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain

Accumulating evidence has demonstrated that the sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 have a role in the modulation of pain transmission at the spinal level through chloride regulation in the pain pathway and by effecting neuronal excitability and pain sensitization. The present study aimed to investigate the analgesic effect of the speciifc sodium-potassium-chloride co-transporter 1 inhibitor bumetanide, and the change in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain. Results showed that intrathecal bumetanide could decrease cumulative pain scores, and could increase thermal and mechanical pain thresholds in a rat model of incisional pain. Sodium-potassium-chloride co-transporter 1 expression in-creased in neurons from dorsal root ganglion and the deep laminae of the ipsilateral dorsal horn following incision. By contrast, potassium-chloride co-transporter 2 expression decreased in neurons of the deep laminae from the ipsilateral dorsal horn. These ifndings suggest that spinal sodium-potassium-chloride co-transporter 1 expression was up-regulated and spinal potassi-um-chloride co-transporter 2 expression was down-regulated following incision. Intrathecal bumetanide has analgesic effects on incisional pain through inhibition of sodium-potassi-um-chloride co-transporter 1.

UPLC-Q-TOF/MS-Based Serum Metabolomics Reveals Potential Anti-tumor Mechanism of Banxia Xiexin Decoction in Colorectal Cancer Mice

Objective To clarify the potential mechanism of Banxia Xiexin Decoction(BXD)on colorectal cancer(CRC)from the perspective of metabolomics.Methods Forty male C57BL/6 mice were randomly divided into normal control(NC),azoxymethane/dextran sulfate sodium(AOM/DSS)model,low-dose BXD(L-BXD),high-dose BXD(H-BXD)and mesalamine(MS)groups according to a random number table,8 mice in each group.Colorectal cancer model was induced by AOM/DSS.BXD was administered daily at doses of 3.915(L-BXD)and 15.66 g/kg(H-BXD)by gavage for consecutive 21 days,and 100 mg/kg MS was used as positive control.Following the entire modeling cycle,colon length of mice was measured and quantity of colorectal tumors were counted.The spleen and thymus index were determined by calculating the spleen/thymus weight to body weight.Inflammatory cytokine and changes of serum metabolites were analyzed by enzyme-linked immunosorbent assay kits and ultra performance liquid chromatography-quadrupole/time-of-flight mass spectrometry(UPLC-Q/TOF-MS),respectively.Results Notably,BXD supplementation protected against weight loss,mitigated tumor formation,and diminished histologic damage in mice treated with AOM/DSS(P<0.05 or P<0.01).Moreover,BXD suppressed expression of serum inflammatory enzymes,and improved the spleen and thymus index(P<0.05).Compared with the normal group,102 kinds of differential metabolites were screened in the AOM/DSS group,including 48 potential biomarkers,involving 18 main metabolic pathways.Totally 18 potential biomarkers related to CRC were identified,and the anti-CRC mechanism of BXD was closely related to D-glutamine and D-glutamate metabolism,phenylalanine,tyrosine and tryptophan biosynthesis,arginine biosynthesis,nitrogen metabolism and so on.Conclusion BXD exerts partial protective effects on AOM/DSS-induced CRC by reducing inflammation,protecting organism immunity ability,and regulating amino acid metabolism.

阿仑膦酸钠干预去卵巢大鼠骨质疏松的腰椎代谢组学分析

背景:研究报道,阿仑膦酸钠的摄入能显著提高骨质疏松症患者的骨密度。目的:利用色谱-质谱技术分析比对阿仑膦酸钠干预去卵巢大鼠模型前后代谢物变化,进一步探索阿仑膦酸钠治疗骨质疏松症的具体机制及作用靶点。方法:选择雌性SD大鼠36只,随机分为骨质疏松症组、阿仑膦酸钠组及假手术组,前两组采用去卵巢法建立骨质疏松症模型。造模4周后,阿仑膦酸钠组大鼠给予阿仑膦酸钠灌胃;假手术组和骨质疏松症组分别给予等体积生理盐水灌胃。连续灌胃12周后,通过色谱-质谱技术分析腰椎代谢物,得出共同差异代谢物,对其进行京都基因与基因组百科全书通路等生物信息学分析。结果与结论:①3组共得到17种共同显著性差异代谢物;②通过京都基因与基因组百科全书富集分析表明,阿仑膦酸钠可能调节不饱和脂肪酸生物合成、亚油酸代谢等通路保护去卵巢模型大鼠;③结果提示,阿仑膦酸钠可能通过干预不饱和脂肪酸生物合成代谢和亚油酸代谢发挥其抗骨质疏松作用,从而达到预防骨质疏松症的目的。

Expression and function of renal and hepatic organic anion transporters in extrahepatic cholestasis

Obstructive jaundice occurs in patients suffering from cholelithiasis and from neoplasms affecting the pancreas and the common bile duct.The absorption,distribution and elimination of drugs are impaired during this pathology.Prolonged cholestasis may alter both liver and kidney function.Lactam antibiotics,diuretics,non-steroidal anti-inflammatory drugs,several antiviral drugs as well as endogenous compounds are classified as organic anions.The hepatic and renal organic anion transport pathways play a key role in the pharmacokinetics of these compounds.It has been demonstrated that acute extrahepatic cholestasis is associated with increased renal elimination of organic anions.The present work describes the molecular mechanisms involved in the regulation of the expression and function of the renal and hepatic organic anion transporters in extrahepatic cholestasis,such as multidrug resistanceassociated protein 2,organic anion transporting polypeptide 1,organic anion transporter 3,bilitranslocase,bromosulfophthalein/bilirubin binding protein,organic anion transporter 1 and sodium dependent bile salt transporter.The modulation in the expression of renal organic anion transporters constitutes a compensatory mechanism to overcome the hepatic dysfunction in the elimination of organic anions.

Possible mechanism for the regulation of glucose on proliferation, inhibition and apoptosis of colon cancer cells induced by sodium butyrate

AIM： To study the effect of glucose on sodium butyrate- induced proliferation inhibition and apoptosis in HT-29 cell line, and explored its possible mechanisms. METHODS： HT-29 cells were grown in RPMI-1640 medium supplemented with 10% fetal calf serum, and were allowed to adhere for 24 h, and then replaced with experimental medium. Cell survival rates were detected by MTr assay. Apoptosis was detected by TUNEL assay. Glucose transport protein 1 （GLUT1） and monocarboxylate transporter 1 （MCT1） mRNA expression was detected by RT-PCR. RESULTS： Low concentration of glucose induced apoptosis and regulated proliferation in HT-29 cell line, and glucose can obviously inhibit the effect of proliferation inhibition and apoptosis induced by sodium butyrate. Glucose also down-regulated the expression of MCT1mRNA （0.28 ± 0.07 vs 0.19± 0.10, P 〈 0.05）, and decreased the expression of GLUTlmRNA slightly （0.18 ± 0.04 vs 0.13 ± 0.03, P 〈 0.05）. CONCLUSION： Glucose can regulate the effect of proliferation inhibition and apoptosis induced by sodium butyrate and this influence may be associated with the intracellular concentration of glucose and sodium butyrate.

Studies on the Effects of Deltamethrin on Sodium Net Transport Through the in vivo Amphibian Skin

The action of micromolar concentrations of Deltamethrin on sodium net transport through the in vivo skin of the South American toad Bufo arenarum was studied. The effect of pure ethanolic insecticide solutions and commercial formulations when applied on the mucosal surface was assayed. Deltamethrin provoked a concentration-independent inhibition; the highest inhibition was found at the lowest concentrations. At highest concentrations of the insecticide the J Na was not altered

Effect of dietary nonphytate phosphorus on laying performance and small intestinal epithelial phosphate transporter expression in Dwarf pink-shell laying hens

This study examined the effects of various levels of dietary nonphytate phosphorus on laying performance and the expression patterns of phosphorus metabolism related genes in Dwarf pink-shell Jaying hens. A total of 405 28-week-old Dwarf pink-shell laying hens were fed the same corn-soybean basal meals but containing 0.20%, 0.25%, 0.30%, 0.35% or 0.40% nonphytate phosphorus. The results showed that feed intake, egg production, and average egg weights were quadratically correlated with dietary nonphytate phosphorus content （P 〈 0.05）, and the highest egg production, feed intake and average egg weights were achieved when dietary nonphytate phosphorus was at 0.3% （P 〈 0.05）. mRNA expression of intestinal sodium phosphorus co-transporter linearly decreased when dietary nonphytate phosphorus increased, mRNA and protein expression of intestinal calbindin and vitamin D receptor correlated quadratically with dietary nonphytate phosphorus, and the highest expression was found when dietary available phosphorus was at 0.2,5% to 0.3%. In conclusion, the ideal phosphorus requirement for Dwarf pink-shell layer hens is estimated to be 0.3% in a corn-soybean diet. With this level of phosphorus supplementation, calbindin and vitamin D receptor reached their highest expression.

Comparative study of renal sodium transport between ouabain-hypertensive rats and ouabain-nonhypertensive rats

Objective: To compare renal sodium transport, using fractional excretions of lithium(FEii)as a marker of proximal tubule sodium reabsorption, between hypertensive and non-hypertensive ouabaintreated rats and further to elucidate the role of ouabain in pathogenesis of hypertension. Methods:Thirty male Sprague-Dawley rats weighting 180-200 g were randomly divided into normal control group and ouabain treated group. Rats were infused with 1 ml/kg · d normal saline or 27.8 μg/kg · d ouabain intraperitoneally once a day respectively. Systolic blood pressure (SBP), heart rate and body weight were recorded weekly. Rats were sacrificed 6 weeks after treatment. Blood and 24-hour urine sample were collected to measure the serum and urinary concentration of sodium, trace lithium and creatinine. Endogenous creatinine clearance rate (Ccr), fractional excretions of sodium (FENa), fractional excretions of lithium (FELi) and fractional reabsorption of sodium in the postproximal tubules (FDRNa) were calculated.Ouabain levels of plasma and renal tissue, plasma renin activity, angiotensin Ⅱ and aldosterone concentration were determined. Results: 65% of the ouabain-treated rats achieved significantly higher SBP after 4weeks, compared with that of the saline control groups or self baseline (P＜0. 01). But in the other 35%of the ouabain-treated rats, their SBP was similar with control group during the experiment (P＞0. 05).The body weight, heart rate and food intake between the 3 groups were no significant differences (P＞0.05). FELi and FDRNa were significantly lower in ouabain-hypertensive group compared with ouabain-nonhypertensive group and control group(P＜0.01 and P＜0.05). The FELi and FDRNa of ouabain-nonhypertensive groups were similar with control group(P＞0.05). Ccr and FENa were comparable between the 3 groups (P＞0. 05). Plasma and renal tissue ouabain levels, plasma renin activity, angiotensin Ⅱ and aldosterone contents in ouabain-hypertensive rats were comparable with ouabain-nonhypertensive rats. Conclusion: Increase of proximal tubule sodium reabsorption play an important role in the pathogenesis of ouabain-hypertensive rats. The change of renal sodium transport may result from regulation to renal Na+ ,K+-ATPase by ouabain.

Sodium Ion Transport by Erythrocytes in hypertensives and Its Response to Antihypertensive Therapy

The transport of sodium ions by erythrocytes and the plasma level of endogenous digitalis-like compound (EDLC) were assessed in 59 patients with essential hypertension before and after theadminstration of nifedipine and prazosin. 20 normal subjects were studied similarly and served as con-trol. It was found that (1) EH patients had a pronounced defect of both the active and passive trans-port of sodium ions by the erythrocytes; (2) a higher plasma level of EDLC was detected in EH pa-tients as compared with that of the control, but the changes of EDLC and soudium pump were notparallel; (3) after the administration of nifedipine and prazosin, the function of sodium pump wasmarkedly improved and the plasma level of EDLC decreased. In addition, the relationship betweenthe transport of sodium ions by erythrocytes and the pathogenesis of EH, and the effects of anti-hypertensive agents were discussed.

基于多组学联用的活鱼暂养及运输应激研究进展

鱼类长途保活运输技术是我国“南鱼北运”实施的主要方法。鱼类在运输过程中受到如低温、盐度变化、碱性胁迫等环境因素影响,结合多组学联合的研究方法对鱼类运输过程中产生的应激进行多维度的分析。识别差异表达基因、蛋白质及代谢物,进而解析调控网络及生物标志物对应激反应的影响,有助于理解鱼类运输过程中的健康状况,优化暂养及运输条件,提高活鱼品质与存活率。综述了近年来鱼类在运输中产生各类应激的组学研究进展,为精准调控鱼类保活运输中的各项环境指标及深入研究活鱼运输应激的相关机理提供参考。

SGLT-2抑制剂达格列净治疗早期糖尿病肾病的临床效果和安全性分析

目的分析在早期糖尿病肾病治疗中采用钠-葡萄糖协同转运蛋白2(Sodium-dependent Glucose Transporters 2,SGLT-2)抑制剂达格列净的疗效和安全性。方法选取2022年3月—2023年12月北京市第六医院收治的100例早期糖尿病肾病患者为研究对象,以随机数表法分为研究组和对照组,各50例。给予全部患者常规治疗,研究组加用达格列净治疗,对照组加用二甲双胍治疗,对比两组血糖水平、肾功能和不良反应发生情况。结果治疗后,研究组空腹血糖为(5.16±0.77)mmol/L,餐后2 h血糖为(7.11±1.38)mmol/L,糖化血红蛋白为(5.05±0.73)%,低于对照组,差异有统计学意义(t=4.592、5.020、5.093,P均<0.05)。治疗后,研究组尿白蛋白/肌酐比值、肾小球过滤率优于对照组,差异有统计学意义(P均<0.05)。研究组不良反应发生率低于对照组,差异有统计学意义(P<0.05)。结论在早期糖尿病肾病治疗中采用SGLT-2抑制剂达格列净疗效显著,可以有效降低血糖水平,改善肾功能,降低不良反应发生率。

硒胁迫对绿豆及小豆硒的富集及转运影响

通过不同浓度硒酸钠胁迫对不同品种小豆及绿豆形态指标的影响分析,确定最适胁迫浓度,测定该浓度胁迫下不同品种植株根、茎、叶中硒的富集、转运系数差异,来确定硒富集及转运力最强和最弱的绿豆或小豆品种。结果表明,对于绿豆和小豆,硒酸钠胁迫的最适浓度为20 mg/L。在该浓度胁迫下,小豆和绿豆叶子出现不同程度的变黄;小豆的7个品种中,吉红11号植株对硒的富集力最强,叶片及茎部硒的含量最高而根部较低,转运能力最强,京农红8号对硒的富集力较好但叶片部分最低,根部较高,转运能力最弱。而绿豆的7个品种中,冀绿10号叶片、茎部及根部硒的富集和转运能力都最强。苏拉2号除了叶片部分硒的富集稍高于保942-34,茎部和根部硒的富集及转运能力都最弱。综上所述,20 mg/L硒酸钠胁迫下,小豆吉红11号的耐受性最强,京农红8号的耐受性最弱;绿豆冀绿10号的耐受性最强,而苏拉2号的耐受性最弱;小豆各品种对硒的转运系数普遍高于绿豆各品种,但对硒的富集能力低于绿豆。

达格列净对2型糖尿病非增殖期视网膜病变的影响

目的:探讨达格列净对2型糖尿病非增殖期视网膜病变(non-proliferative diabetic retinopathy,NPDR)的影响。方法:选取2021年10月—2023年6月湖南师范大学附属湘东医院收治的88例2型糖尿病NPDR患者。随机将其分为观察组及对照组,各44例。两组均给予常规降糖治疗,观察组加用达格列净治疗。比较两组治疗前后血糖指标及相关指标。分析血管内皮生长因子(vascular endothelial growth factor,VEGF)与血糖波动指标的相关性。结果:治疗后,两组空腹血糖(fasting blood glucose,FBG)、餐后2 h血糖(2 h postprandial blood glucose,2 h PBG)、糖化血红蛋白(glycosylated hemoglobin,HbA1c)、血糖水平标准差(standard deviation of blood glucose,SDBG)、餐后血糖波动幅度(postprandial glucose excursion,PPGE)、最大血糖波动幅度(large amplitude glycemic excursion,LAGE)均下降,观察组SDBG、PPGE、LAGE均低于对照组,差异有统计学意义(P<0.05)。治疗后,两组VEGF、黄斑中心凹厚度均下降,最佳矫正视力(best-corrected visual acuity,BCVA)升高,观察组VEGF、黄斑中心凹厚度均低于对照组,BCVA高于对照组,差异有统计学意义(P<0.05)。Pearson相关性分析结果显示:VEGF与SDBG、PPGE、LAGE均呈正相关(P<0.05)。结论:达格列净能够改善血糖波动,降低VEGF水平,对2型糖尿病NPDR有保护作用。

顶端钠依赖性胆汁酸转运蛋白(ASBT)在肝胆疾病中的作用

顶端钠依赖性胆汁酸转运蛋白(ASBT)是负责胆汁酸肠道重吸收的关键转运体,对维持胆汁酸和胆固醇稳态起重要作用,其表达受到转录因子、核受体和肠道微生物等多种因素的调控。ASBT的表达和功能异常会导致胆汁酸及胆固醇代谢紊乱,引起多种肝胆相关疾病。目前,ASBT作为一种治疗靶点已受到广泛关注。本文阐述了ASBT的生物学特征及表达调控机制,并对ASBT在肝胆疾病中的作用进行了综述,为相关疾病的治疗提供新方向。

射血分数保留的心力衰竭合并心房颤动的诊疗进展

心房颤动(AF)与射血分数保留的心力衰竭(HFpEF)常常并存,HFpEF患者中AF发病率约为40%~60%,二者通过不同的机制相互影响,及时的诊断及治疗对此类患者很有必要。本文旨在探讨AF对HFp EF诊断和预后的影响,以及HFp EF合并AF的最新治疗手段。

六堡茶茶褐素中酚类化合物及蛋白质组分分析

本研究通过甲醇提取茶褐素,将其分为可提取部分(记为FTB)和不可提取部分(记为BTB),采用傅里叶变换红外光谱、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、蛋白质印迹和超高效液相色谱-高分辨质谱方法开展组分分析。结果表明,茶褐素为多羟基的芳香族物质,含有蛋白质、氨基酸和肽等含氮化合物;在蛋白质分子质量63~75 kDa附近具有条带,总体为弥散型的长条且可能被多酚等物质修饰;非靶向代谢组学共鉴定出297种化合物,以差异倍数(fold change,FC)>2或FC<0.5和P<0.05为标准进行筛选,发现BTB与FTB之间有137种化合物存在显著差异,主要为酚类化合物(37种);通过主成分分析和正交偏最小二乘判别分析获得了FTB与BTB的5种酚类化合物(儿茶素、2,3-二羟基苯甲酸、没食子酸、4-羟基香豆素和咖啡酸),它们不仅可以区分FTB和BTB,还有可能是茶褐素的主要不可提取酚类。本研究解析了六堡茶茶褐素的多酚谱及其特征性多酚,提出了蛋白质-多酚复合物的推论,有助于丰富黑茶茶褐素中蛋白质的相关研究,推动黑茶茶褐素的物质组成及功能活性的进一步研究。