Stem cell-like memory T cells:Role in viral infections and autoimmunity

Stem cell-like memory T(TSCM)cells possess stem cell properties including multipotency and self-renewal and are being recognized as emerging players in various human diseases.Advanced technologies such as multiparametric flowcytometry and single cell sequencing have enabled their identification and molecular characterization.In case of chronic viral diseases such as human immunodeficiency virus-1,CD4+T_(SCM) cells,serve as major reservoirs of the latent virus.However,during immune activation and functional exhaustion of effector T cells,these cells also possess the potential to replenish the pool of functional effector cells to curtail the infection.More recently,these cells are speculated to play important role in protective immunity following acute viral infections such as coronavirus disease 2019 and might be amenable for therapeutics by ex vivo expansion.Similarly,studies are also investigating their pathological role in driving autoimmune responses.However,there are several gaps in the understanding of the role of T_(SCM) cells in viral and autoimmune diseases to make them potential therapeutic targets.In this minireview,we have attempted an updated compilation of the dyadic role of these complex T_(SCM) cells during such human diseases along with their biology and transcriptional programs.

Use of priming strategies to advance the clinical application of mesenchymal stromal/stem cell-based therapy

Mesenchymal stromal/stem cells(MSCs)have garnered significant attention in the field of regenerative medicine due to their remarkable therapeutic potential.MSCs play a pivotal role in maintaining tissue homeostasis and possess diverse functions in tissue repair and recovery in various organs.These cells are charac-terized by easy accessibility,few ethical concerns,and adaptability to in vitro cultures,making them a valuable resource for cell therapy in several clinical conditions.Over the years,it has been shown that the true therapeutic power of MSCs lies not in cell engraftment and replacement but in their ability to produce critical paracrine factors,including cytokines,growth factors,and exosomes(EXOs),which modulate the tissue microenvironment and facilitate repair and regeneration processes.Consequently,MSC-derived products,such as condi-tioned media and EXOs,are now being extensively evaluated for their potential medical applications,offering advantages over the long-term use of whole MSCs.However,the efficacy of MSC-based treatments varies in clinical trials due to both intrinsic differences resulting from the choice of diverse cell sources and non-standardized production methods.To address these concerns and to enhance MSC therapeutic potential,researchers have explored many priming strategies,including exposure to inflammatory molecules,hypoxic conditions,and three-dimensional culture techniques.These approaches have optimized MSC secretion of functional factors,empowering them with enhanced immunomodulatory,angiogenic,and regenerative properties tailored to specific medical conditions.In fact,various priming strategies show promise in the treatment of numerous diseases,from immune-related disorders to acute injuries and cancer.Currently,in order to exploit the full therapeutic potential of MSC therapy,the most important challenge is to optimize the modulation of MSCs to obtain adapted cell therapy for specific clinical disorders.In other words,to unlock the complete potential of MSCs in regenerative medicine,it is crucial to identify the most suitable tissue source and develop in vitro manipulation protocols specific to the type of disease being treated.

Optimization and Characterization of Combined Degumming Process of Typha angustata L. Stem Fibers

Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).

Relationship between Bending Property and Density of Wheat Stem

[ Objective] The aim is to research the relationship between bending property and density of wheat stem. [ Method ] The bending properties such as elastic modulus, bending strength, flexural rigidity, moment of inertia, density and water content of the second base internodes of Zhengmai 9023 and Yumai 25 were determined. [ Result] The results show that during filling stage, there are significant differences in the elastic modulus, moment of inertia, flexural rigidity and density among wheat varieties, while there are no significant differences in the bending strength and water content among wheat varieties. The moment of inertia, flexural strength and flexural rigidity have positive relationship to density but negative relationship to water content. [ Conclusion] The study results provide some references for the research on high yield cultivation and lodging resistance of wheat.

Phenotype-Directed DNA Nanomachine for in Situ Analysis of Stem Cell-like Subpopulation in Breast Cancer

The cancer stem cell hypothesis provides a basis for prediction of the recurrence and risk of metastasis in breast cancer.However,the unique expression pattern of stemness markers and the presence of nonstem-like cancer cells with varied phenotypes have brought great challenges to the characterization of breast cancer stem cells.To address these challenges,a phenotype-directed DNA nanomachine has been designed for high-accuracy labeling and in situ analysis of the stem cell-like subpopulation in breast cancer.The key for the design is to use cell surfaceanchored inputs to activate the nanomachine,which undergoes different branch migration pathways such that the signal strand can only be brought onto the cancer cells having the stem cell-like phenotype.Highly sensitive determination and single-step isolation of the stem cell-like subpopulation were achieved by incorporating functional groups into the signal strand such that the nanomachine was successfully applied in a tumor-bearing mouse model.Overall,the approach provides for a substantial improvement in capability for the analysis of the breast cancer stem cell-like subpopulation,and it is expected that the new approach will advance the use of DNA nanomachines in cancer-related studies.

Structural properties of scaffolds:Crucial parameters towards stem cells differentiation

Tissue engineering is a multidisciplinary field that applies the principles of engineering and life-sciencesfor regeneration of damaged tissues. Stem cells have attracted much interest in tissue engineering as a cell source due to their ability to proliferate in an undifferentiated state for prolonged time and capability of differentiating to different cell types after induction. Scaffolds play an important role in tissue engineering as a substrate that can mimic the native extracellular matrix and the properties of scaffolds have been shown to affect the cell behavior such as the cell attachment, proliferation and differentiation. Here, we focus on the recent reports that investigated the various aspects of scaffolds including the materials used for scaffold fabrication, surface modification of scaffolds, topography and mechanical properties of scaffolds towards stem cells differentiation effect. We will present a more detailed overview on the effect of mechanical properties of scaffolds on stem cells fate.

Intravitreal stem cell paracrine properties as a potential neuroprotective therapy for retinal photoreceptor neurodegenerative diseases

Retinal degenerations are the leading causes of irreversible visual loss worldwide. Many pathologies included under this umbrella involve progressive degeneration and ultimate loss of the photoreceptor cells, with age-related macular degeneration and inherited and ischemic retinal diseases the most relevant. These diseases greatly impact patients' daily lives, with accompanying marked social and economic consequences. However, the currently available treatments only delay the onset or slow progression of visual impairment, and there are no cures for these photoreceptor diseases. Therefore, new therapeutic strategies are being investigated, such as gene therapy, optogenetics, cell replacement, or cell-based neuroprotection. Specifically, stem cells can secrete neurotrophic, immunomodulatory, and anti-angiogenic factors that potentially protect and preserve retinal cells from neurodegeneration. Further, neuroprotection can be used in different types of retinal degenerative diseases and at different disease stages, unlike other potential therapies. This review summarizes stem cell-based paracrine neuroprotective strategies for photoreceptor degeneration, which are under study in clinical trials, and the latest preclinical studies. Effective retinal neuroprotection could be the next frontier in photoreceptor diseases, and the development of novel neuroprotective strategies will address the unmet therapeutic needs.

S100 protein expression during induced Schwann cell-like cell differentiation of rat bone marrow mesenchymal cells in vitro

BACKGROUND： S100 protein can promote axonal growth. Therefore, transplantation of induced bone marrow-derived mesenchymal stem cells （MSCs） that can secrete S100 may provide a beneficial microenvironment for neural regeneration. OBJECTIVE： To explore the changes in S100 expression during rat MSCs differentiation into Schwann ceils in vitro. DESIGN, TIME AND SETTING： This cytology experiment was performed at the Jiangsu Key Laboratory of Neuroregeneration, Nantong University in China, from January 2006 to May 2007. MATERIALS： The rabbit anti-S100 polyclonal antibody was purchased from Dako, Denmark; the mouse anti-rat S100 monoclonal antibody was purchased from Sigma, USA. METHODS： MSCs were cultured from adult Sprague-Dawley rat femur and tibia. Cell proliferation was determined by the MTT method and CD markers, and cell cycle was measured by flow cytometry. MSCs were induced to differentiate into SC cells. SC cells were stained for S100 protein, glial fibrillary acidic protein, and low-affinity nerve growth factor receptor. S100 protein and mRNA levels were evaluated by flow cytometry, Western blot, and reverse transcription-polymerase chain reaction. MAIN OUTCOME MEASURES： S100 protein and mRNA expression. RESULTS： MSCs exhibited high amplification potential over eight passages. Prior to induction, the majority of MSCs were at the G0/G1 phase of the cell cycle. After induction, MSCs displayed morphology changes similar to Schwann cells. Moreover, induction increased S100 mRNA levels. Immunofluorescence showed that MSCs expressed S100 protein, glial fibrillary acidic protein, and low-affinity nerve growth factor receptor at 7 days of induction. Induction also increased S100 protein levels compared with untreated MSCs. CONCLUSION： MSCs are capable of differentiating into Schwann cells-like cells under conditional induction in vitro, with increasing S100 mRNA and protein expression.

Biochemical properties of norepinephrine as a kind of neurotransmitter secreted by bone marrow-derived neural stem cells induced and differentiated in vitro

BACKGROUND： It has been proved by many experimental studies from the aspects of morphology and immunocytochemistry in recent years that bone marrow stromal cells （BMSCs） can in vitro induce and differentiate into the cells possessing the properties of nerve cells. But the functions of BMSCs-derived neural stem cells（NSCs） and the differentiated neuron-like cells are still unclear. OBJECTIVE： To observe whether bone marrow-derived NSCs can secrete norepinephrine （NE） under the condition of in vitro culture, induce and differentiation, and analyze the biochemical properties of BMSCs-derived NSCs. DESIGN： A non-randomized and controlled experimental observation SETTING ： Institute of Neuromedicine of Chinese PLA, Zhujiang Hospital, Southern Medical University MATERIALS： This experiment was carried out in the Institute of Neuromedicine of Chinese PLA, Zhujiang Hospital, Southern Medical University. The bone marrow used in the experiment was collected from 1.5- month-old healthy New Zealand white rabbits. METHODS： This experiment was carried out in the Institute of Neuromedicine of Chinese PLA, Zhujiang Hospital, Southern Medical University. The bone marrow used in the experiment was collected from 1.5 month-old healthy New Zealand white rabbits. BMSCs of rabbits were isolated and performed in vitro culture, induce and differentiation with culture medium of NSCs and differentiation-inducing factor, then identified with immunocytochemical method. Experimental grouping： ①Negative control group： L-02 hepatic cell and RPMI1640 culture medium were used. ② Background culture group： Only culture medium of NSCs as culture solution was added into BMSCs to perform culture, and 0.1 volume fraction of imported fetal bovine serum was supplemented 72 hours later. ③Differentiation inducing factor group： After culture for 72 hours, retinoic acid and glial cell line-derived neurotrophic factors were added in the culture medium of BMSCs and NSCs as corresponding inducing factors. The level of NE in each group was detected on the day of culture and 5, 7, 14 and 20 days after culture with high performance liquid chromatography （HPLC）. The procedure was conducted 3 times in each group.Standard working curve was made according to the corresponding relationship of NE concentration and peak area. The concentration of NE every 1×10^7 cells was calculated according to standard curve and cell counting. MAIN OUTCOME MEASURES ： The level of NE of cultured cells was detected with HPLC; immunocytochemistrical identification of Nestin and neuron specific nuclear protein was performed. RESULTS： ① On the 14^th day after cell culture, BMSCs turned into magnus and round cells which presented Nestin-positive antigen, then changed into neuron-like cells with long processus and presented neuron specific nuclear protein -positive antigen at the 20^th day following culture. ② The ratio of NE concentration and peak area has good linear relationship, and regression equation was Y=1.168 36＋0.000 272 8X,r=-0.998 4. Coefficient variation （CV） was 〈 5% and the recovery rate was 92.39%（ Y referred to concentration and X was peak area）.③NE was well detached within 10 minutes under the condition of this experiment. ④ NE was detected in NSCs and their culture mediums, which were cultured for 7, 14 and 20 days respectively, but no NE in BMSCs, NSCs-free culture medium and L-02 hepatic cell which were as negative control under the HPLC examination. Analysis of variance showed that the level of NE gradually increased following the elongation of culture time （P 〈 0.01 ）. No significant difference in the level of NE existed at the same time between differentiation inducing factor group and basic culture group（P 〉 0.05）. CONCLUSION ： BMSCs of rabbits can proliferate in vitro and express Nestin antigen; They can differentiate into neuron-like cells, express specific neucleoprotein of mature neurons, synthesize and secrete NE as a kind of neurotransmitter.

Different priming strategies improve distinct therapeutic capabilities of mesenchymal stromal/stem cells:Potential implications for their clinical use

Mesenchymal stromal/stem cells(MSCs)have shown significant therapeutic potential,and have therefore been extensively investigated in preclinical studies of regenerative medicine.However,while MSCs have been shown to be safe as a cellular treatment,they have usually been therapeutically ineffective in human diseases.In fact,in many clinical trials it has been shown that MSCs have moderate or poor efficacy.This inefficacy appears to be ascribable primarily to the heterogeneity of MSCs.Recently,specific priming strategies have been used to improve the therapeutic properties of MSCs.In this review,we explore the literature on the principal priming approaches used to enhance the preclinical inefficacy of MSCs.We found that different priming strategies have been used to direct the therapeutic effects of MSCs toward specific pathological processes.Particularly,while hypoxic priming can be used primarily for the treatment of acute diseases,inflammatory cytokines can be used mainly to prime MSCs in order to treat chronic immune-related disorders.The shift in approach from regeneration to inflammation implies,in MSCs,a shift in the production of functional factors that stimulate regenerative or anti-inflammatory pathways.The opportunity to fine-tune the therapeutic properties of MSCs through different priming strategies could conceivably pave the way for optimizing their therapeutic potential.

Phytochemicals Analysis, Antioxidant Capacities and Antimicrobial Properties of Ethyl Acetate Extract of Stem Bark of the Garlic Tree Scorodocarpus borneensis Becc.

The objective of this study was to examine the phytochemical components, antioxidant activity and antibacterial property of ethyl acetate extract of the stem bark of garlic tree （Scorodocarpus borneensis）. The dried stem bark of S. borneensis were collected and homogenized after drying at room temperature （32℃） for 30 d. The stem barks were extracted by macerated method using 95% ethanol and then fractionated with ethyl acetate. The dried ethyl acetate extract was subjected to phytoehemical screening to determine the presence of bioactive components using gas chromatography-mass spectrometry （GC-MS）. Antioxidant activity of the extract in vitro was examined by 2,2-diphenyl-l-picryl-hydrazyl （DPPH） radical scavenging assay. The antibacterial activity against gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli was performed by disc diffusion assay. GCMS results revealed the presence of 14 different phytocompounds, viz, tetratriacontyl trifluoroacetate （41.61%）, 2-pentanone （13.65%）, oxacyclotetradecane-2,11-done （7.87%）, cinnamic acid （7.53%）, 10-octadecanoic acid （6.50%）, 1,2-benzeno dicarboxylix acid （4.99%）, octadecanoic acid （4.51%）, hexadecanoic acid （4.16%）, beta tumerone （3.01%）, 9-octadecenoic acid （1.70%）, tricosanol （1.38%）, hexadecano-phenone （1.36%）, 1-nonadecanol （0.93%） and n-nonadecanol （0.82%）. In vitro antioxidant activity （IC50） was found at 55.524 ppm as high powerful. The results of agar diffusion method showed that the ethyl acetate extracts had an antibacterial activity of 6.687 ± 0.800 mm againts S. aureus at 10% （w/v） and 7.500 ± 0.735 mm against E. coli at 10% （w/v） as moderate category. These findings suggest that S. borneensis stem bark is a valuable sources of bioactive compounds with promising as antioxidant and antibacterial sources.

杂交粳稻茎秆力学性状与理化特征对抗倒伏能力的影响

倒伏严重影响着水稻的产量和品质,为探究田间自然栽培条件下杂交粳稻茎秆力学性状与理化特征对抗倒伏能力的影响,研究选取北方地区生产上主要推广的弯曲穗型杂交粳稻品种辽优2006(LY2006)、辽优5218(LY5218)、辽优5273(LY5273)为供试对象,易倒伏常规粳稻品种农林313(NL313(CK))为对照,测量其农艺性状和微观组织构成等理化指标,并通过弯曲试验及拉伸试验,测定其茎秆最大抗折力、断裂弯矩、抗弯截面系数、单茎自重质量矩、弯曲强度、杨氏弹性模量、惯性矩等力学指标,并研究测量的理化指标及力学指标与倒伏指数之间的相关关系。结果表明:供试对象的倒伏指数和对照之间存在极显著差异(P<0.01),供试对象抗倒伏性显著高于对照。供试对象和对照在株高、基部节间长度、组织构成等理化指标及力学指标间均存在极显著差异(P<0.01),供试对象的株高、单穗鲜质量均大于对照,因此,在相同的栽培条件下,并不是株高越矮、穗越轻,抗倒伏能力就越强。缩短基部节间长度、延长叶鞘长度、提高组织厚度及维管束面积、增加纤维素、木质素及钾元素含量等均能有效提升水稻植株的抗倒伏能力。研究还发现,水稻植株的抗倒伏能力与其茎秆最大抗折力、断裂弯矩、抗弯截面系数、弯曲强度、杨氏弹性模量之间存在极显著正相关(P<0.01),与单茎自重质量矩、惯性矩之间存在极显著负相关(P<0.01),选取其作为水稻植株抗倒伏能力的参考指标是可行的。研究结果可为北方杂交粳稻抗倒伏品种选育、改良及抗倒伏农艺性状调控提供综合的数据支持和理论支撑。

番泻苷B通过Wnt/β-catenin通路抑制视网膜母细胞瘤HXO-Rb44细胞增殖、凋亡和侵袭

目的探究番泻苷B对视网膜母细胞瘤HXO-Rb44细胞增殖、凋亡、侵袭及Wnt/β-catenin信号通路的影响。方法通过采用不同剂量(0、5、10、20μmol/L)番泻苷B处理HXO-Rb44细胞,将细胞随机分为4组:Control组,番泻苷B 5、10、20μmol/L组。MTT法检测细胞活力;克隆形成实验检测克隆形成率;流式细胞仪检测细胞凋亡率;Transwell检测侵袭细胞数;细胞成球实验检测细胞成球直径和细胞成球数目;蛋白质印迹检测cleaved caspase-3、caspase-3、MMP-2、MMP-9、SOX2、OCT4、CD44、Wnt1、β-catenin蛋白表达。结果与Control组比较,番泻苷B 10、20μmol/L组细胞活力、克隆形成率显著降低(P<0.05),细胞凋亡率和cleaved caspase-3/caspase-3表达显著升高(P<0.05),侵袭细胞数和MMP-2、MMP-9蛋白表达显著降低(P<0.05),细胞成球直径、细胞成球数目和SOX2、OCT4、CD44蛋白表达显著降低(P<0.05),Wnt1、β-catenin蛋白表达显著降低(P<0.05)。结论番泻苷B可抑制视网膜母细胞瘤HXO-Rb44细胞增殖、侵袭和干细胞样特性,诱导细胞凋亡,抑制Wnt/β-catenin信号通路的活化。

马铃薯茎叶还田对土壤理化性质及细菌群落结构的影响

【目的】探究马铃薯茎叶还田对土壤理化性质和细菌群落结构的影响。【方法】基于土壤理化分析和Illumina高通量测序技术,对比分析马铃薯茎叶还田(处理组R)与不还田(处理组NR)土壤理化指标和细菌群落结构的差异。【结果】与处理CK相比,马铃薯茎叶还田提高土壤pH及有机质、碱解氮、有效磷、速效钾含量,其中速效钾含量增幅最大,达42.36~141.53 mg/kg。马铃薯茎叶还田显著影响土壤细菌群落结构,在第45、90天时,还田处理土壤中12个细菌类群丰度显著提高,且还田处理较不还田处理土壤细菌群落的物种多样性显著提高。各处理土壤细菌群落的种间互作关系主要发生在酸杆菌门、放线菌门(Actinobacteriota)和变形菌门,且马铃薯茎叶还田处理较不还田处理,土壤细菌群落种间互作强度显著提高。相关性分析表明,Latescibacterota、脱硫菌门(Desulfobacterota)与有效磷含量呈极显著负相关,与碱解氮、有机质含量呈显著正相关;粘球菌门(Myxococcota)、Bdellovibrion⁃ota、髌骨菌门(Patescibacteria)、肠杆菌门(Entotheonellaeota)、芽单胞菌门(Gemmatimonadota)、硝化螺旋菌门(Nitrospirota)、变形菌门(Proteobacteria)与速效钾含量呈显著正相关。【结论】马铃薯茎叶还田处理可以提高土壤养分含量,显著提高土壤细菌群落的物种多样性及群落物种互作强度,土壤速效钾、有效磷、碱解氮及有机质含量等理化指标与土壤细菌群落物种组成存在显著的相关关系。

莲蓬采摘末端执行器设计

针对目前人工收获莲蓬效率低,莲蓬机械化收获设备发展缓慢的问题,对莲蓬采摘末端执行器进行设计。为确定莲蓬茎秆的相关力学参数,以成熟期莲蓬茎秆作为试验材料,使用质构仪对莲蓬茎秆进行剪切力学特性试验。试验表明,剪切速度在500 mm/min以内时,剪切速度、茎秆直径对莲蓬茎秆剪切强度影响不显著。剪切位置对莲蓬茎秆剪切强度影响最大,剪切位置越靠近莲蓬,所需要的剪切力越小。成熟莲蓬的茎秆剪断所需的剪切力为10.29~132.17 N,剪切应力为0.20~2.71 MPa。由此确定莲蓬采摘末端执行器的最佳采摘范围及所需剪切力,并根据试验结果设计莲蓬采摘末端执行器。采摘试验表明,所设计的莲蓬夹持剪切装置的莲蓬剪切成功率为100%,但由于莲蓬从末端执行器滑落,导致整体采摘成功率为92%。

黄芩茎叶葡萄糖醛酸水解酶提取工艺、酶学性质、实际应用研究

目的研究黄芩茎叶葡萄糖醛酸水解酶(sbslGUS)提取工艺、酶学性质、实际应用。方法在单因素试验基础上,以粒度、加水量、提取时间、提取次数为影响因素,酶活性为评价指标,正交试验优化提取工艺。分析底物(黄芩苷)浓度与酶解速度的关系,计算V_(max)、K_(m),考察pH值、温度、金属离子对酶活性的影响,评价pH稳定性、热稳定性。sbslGUS酶解黄芩苷以制备黄芩素,考察pH值、温度、反应时间、底物初始浓度、加酶量对转化率的影响。结果最优提取工艺为粒度40目,加水量10倍,提取时间15 min,提取次数3次。酶解符合酶促反应动力学,K_(m)为0.0063 mol/L,V_(max)为70.42μmol/h,在pH值6.0、温度45℃、金属离子100 mmol/L Cu2+下酶活性最强,sbslGUS在pH值4.0~7.0、温度4~30℃范围内稳定性良好。最优制备工艺为pH值6.0,温度45℃,反应时间12 h以上,底物初始浓度67.2 mmol/L,加酶量1 mL/0.269 mmol黄芩苷,转化率为97.83%。结论sbslGUS酶解效率高,条件温和,可为获取黄芩素提供简便的制备方法,并且拓展了黄芩茎叶应用途径。

火龙果茎多糖组成及抗氧化稳定性分析

目的:以火龙果茎中提取的多糖为研究对象,分析其理化特性和抗氧化活性,并进一步探讨不同储存条件与食品加工方式对其抗氧化稳定性的影响。方法:热水浸提醇沉法制备火龙果茎多糖,分别采用苯酚硫酸法、NaNO_(2)-Al(NO_(3))_(3)-NaOH显色法、福林酚法和离子色谱法分析多糖的总糖、黄酮和酚类含量以及单糖组成,扫描电子显微镜(SEM)观察多糖微观形态,并以抑制羟基自由基能力为抗氧化指标,通过模拟不同食品储存和加工条件,系统地研究火龙果茎多糖的抗氧化稳定性。结果:热水提取法得到的火龙果茎多糖的得率为7.22%,总糖含量为334.63 mg/g,黄酮和酚类残留量分别为5.91 mg/g和5.05 mg/g,进一步分析其主要由葡萄糖、半乳糖、鼠李糖、半乳糖醛酸、阿拉伯糖和甘露糖等组成,单糖摩尔比为5.27:2.77:0.77:0.71:0.32:0.17;在SEM下,火龙果茎多糖呈现紧密、多孔的不规则形状;火龙果茎多糖具有较好的抗氧化活性,随着多糖质量浓度的增加,其抑制羟基自由基的能力增强(P<0.05)。温度、pH、部分金属离子(钙、钾和钠离子)、部分食品添加剂(柠檬酸、苯甲酸钠和葡萄糖)和杀菌方式对火龙果茎多糖抗氧化稳定性的影响较小;光照对火龙果茎多糖抗氧化稳定性影响较大,随着光照时间的延长,火龙果茎多糖对羟基自由基的抑制能力逐渐降低,故耐光性较差;而增加金属铁、铜离子和蔗糖溶液的质量浓度也会显著(P<0.05)降低火龙果茎多糖抗氧化活性。结论:火龙果茎多糖具有良好的抗氧化稳定性,但是在火龙果茎的储存和食品加工中应避免长期光照、直接接触金属铁离子和铜离子以及高浓度的蔗糖溶液。

香蕉茎秆纤维/抗菌纤维混纺纱的制备及其性能

为促进天然香蕉茎秆纤维在纺织服装领域的应用,采用半精纺纺纱工艺,以香蕉茎秆纤维(BF)、优可丝安泰贝抗菌纤维(ATB)和稀土抑菌再生纤维素纤维(XT)为原料,制备了混纺比为50/50、65/35、70/30、85/15的8种BF/抗菌纤维混纺纱和1种BF纯纺纱,表征了纱线的线密度和捻度,探究了混纺比例与纱线力学性能、质量指标、抗菌性能的关系。结果表明,9种纱线实测的线密度和捻度与设计值存在偏差,但其偏差在允差范围内;ATB和XT的加入提高了BF纯纺纱的力学性能与抗菌性能,改善了BF纯纺纱的条干均匀度、毛羽指数、棉结、粗节、细节等质量指标,且香蕉/抗菌纤维混纺纱强度高、毛羽少、手感柔软,适宜开发各类机织和针织面料。

不同干燥方式对西兰花茎和叶品质的影响

为考察和评价西兰花副产物(茎和叶)的加工适应性并对其合理利用提供参考,本研究对采用真空冷冻干燥(vacuum freeze drying,FD)、微波冷冻干燥(microwave freeze drying,MFD)、热泵干燥(heat pump drying,HPD)及热风干燥(hotairdrying,HAD)制备的西兰花茎粉和叶粉的理化性质及营养品质进行研究。结果表明:MFD西兰花茎的色泽同鲜样差异ΔE为8.52±0.02,HAD的ΔE为30.27±0.28,说明MFD保色效果较好;西兰花茎粉的中位粒径范围为31.19~52.09μm,叶粉的中位粒径范围为32.30~40.47μm,叶粉持水力和持油力均低于茎粉,但其膨胀力较茎粉高,FD西兰花茎粉持水力为(11.40±0.46)g/g,MFD西兰花茎粉持油力为(1.40±0.04)g/g;FD和MFD能较好地保持西兰花茎和叶的微观结构,有明显孔洞;FD和MFD处理等量西兰花茎的比能耗分别为7.35、3.26 kW·h/kg,与FD相比,MFD节约了55.65%的能耗。MFD能较好地保存热敏性和易氧化的营养成分,所以具有良好的抗氧化活性,当MFD西兰花叶提取物质量浓度为0.125 mg/100 mL时,其1,1-二苯基-2-三硝基苯肼自由基清除率、2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除率及铁离子总还原能力分别为70.21%、71.11%、(0.31±0.01)mmol/g。综上可知,西兰花茎粉和叶粉理化性质和营养品质良好,可作为开发功能性食品的原料,并且干燥技术的应用能够为西兰花茎和叶的合理利用提供可行参考。

白术多糖对肝癌细胞干样特性、上皮间质转化和Akt/NF-κB磷酸化的影响

目的探讨白术多糖(AMPs)对肝癌细胞的干样特性和上皮间质转化(EMT)以及Akt/NF-κB磷酸化的影响。方法培养肝癌HepG2细胞,随机分为空白对照组,AMPs低、中、高浓度处理组(50、100、200μg/ml),显微下观察细胞成球情况,蛋白印迹(Western blotting)检测AMPs对HepG2细胞生长标记物、干样标记物及Akt/NF-κB通路的表达,实时荧光定量PCR(qPCR)和免疫荧光检测EMT标记物的表达。结果与空白对照组比较,100、200μg/ml浓度的AMPs处理后,HepG2细胞Ki-67、PCNA蛋白表达下调,p21蛋白表达上调(P<0.05);细胞成球数量减少,球体直径明显降低(P<0.05);SOX2、Oct4和Nanog蛋白表达下调(P<0.05);E-cad mRNA表达水平升高,N-cad mRNA表达水平和Vimentin阳性染色细胞数量降低(P<0.05);Akt和p-P65 NF-κB磷酸化水平降低(P<0.05)。50μg/ml AMP组上述指标与空白对照组比较,差异无统计学意义(P>0.05)。结论AMPs可抑制HepG2细胞的活性、干细胞样特性及EMT能力,抑制Akt/NF-κB磷酸化水平可能是其潜在的作用机制。