大叶苦丁茶抗氧化成分及抗氧化性能研究（I）

对冬青科大叶苦丁茶进行了初步的成分分析,同时采用可见分光光度计法测定其活性部位的POV值,并进行抗氧化性能分析,其中所含多酚和黄酮部位的抗氧化性能较强,具有进一步开发及应用的价值。     

大叶苦丁茶抗氧化成分及抗氧化性能研究(Ⅰ)

对冬青科大叶苦丁茶进行了初步的成分分析 ,同时采用可见分光光度计法测定其活性部位的 POV值 ,并进行抗氧化性能分析 ,其中所含多酚和黄酮部位的抗氧化性能较强 ,具有进一步开发及应用的价值。     

在5种食用油中野菊花挥发油的抗氧化能力研究

采用水蒸气蒸馏法提取野菊[Dendranthema indicum (L. ) Des Moul. ]干燥头状花序的挥发油,以常用抗氧化剂二丁基羟基甲苯(BHT)为对照,并以油脂的过氧化值(POV)为指标,对野菊花挥发油在猪油、花生油、葵花籽油、玉米油和大豆油中的抗氧化能力进行了比较分析.结果表明,在供试的5种食用油中,各处理组(50.0 g食用油中野菊花挥发油添加量分别为0.005、0.025、0.050、0.075和0.100 g)的POV值均随贮藏时间(猪油和大豆油为28 d,花生油、葵花籽油和玉米油为35 d)的延长逐渐增大;随挥发油添加量的增加,5种食用油的POV值总体上呈逐渐减小的趋势.在28 d的贮藏期内,仅添加了0.075～0.100 g挥发油的玉米油和大豆油的POV值极显著低于对照(0.010 g BHT)和空白;在贮藏的前中期,仅添加了0.075～0.100 g挥发油的花生油和葵花籽油的POV值极显著低于对照和空白,但在贮藏的中后期花生油和葵花籽油各处理组的POV值则极显著高于对照;添加了挥发油的猪油在28 d的贮藏期内其POV值基本上极显著高于对照但低于空白.说明在玉米油和大豆油中添加适量的野菊花挥发油具有较强抗氧化能力,且抗氧化效果总体上高于BHT;而添加适量的野菊花挥发油也能在一定程度上延缓花生油和葵花籽油的氧化过程,但抗氧化效果低于BHT;而添加适量的野菊花挥发油仅能部分缓解猪油的氧化过程,其抗氧化效果明显低于BHT.研究结果显示,在不同的食用油中野菊花挥发油均有一定的抗氧化作用,但其抗氧化能力有一定的差异,这种差异与食用油种类、野菊花挥发油的添加量及食用油的贮藏时间均有一定的关系.     

桦褐孔菌提取物抗氧化与糖苷酶抑制活性研究

为探索桦褐孔菌(Inonotus obliquus (Fr.) Pila)生物活性与化学成分之间的相关性,本文用乙醇回流提取、梯度萃取得桦褐孔菌的石油醚、乙酸乙酯、正丁醇和水提取物,对其进行黄酮和多酚类化合物的含量测定,并从抗氧化和降血糖两个方面测定了总还原力、清除DPPH自由基、抑制肝脂质过氧化、抑制α-葡萄糖苷酶活性四种体外模型对不同提取物活性的影响.结果显示:乙酸乙酯和正丁醇提取物所含的黄酮和多酚类化合物较多(P<0.01)且抗氧化和降血糖活性较好.因此,桦褐孔菌抗氧化和降血糖活性的大小与其所含黄酮和多酚类化合物量密切相关,本研究结果为桦褐孔菌生物活性成分的深入研究奠定了良好的基础.     

响应面法优化芦荟中抗氧化活性成分的提取工艺

对芦荟中抗氧化活性物质提取工艺及其成分进行研究,通过单因素实验和响应面优化,以提取物对DPPH自由基的清除率为抗氧化的考察指标,得到芦荟中抗氧化活性成分的提取工艺条件:提取温度29 ℃、料液比(g/mL)1:33、提取时间107 s、微波功率500 W,微波辅助水提,此条件下得到的提取物对DPPH自由基的清除率达91.414%.提取物活性成分分析表明:提取物中芦荟甙含量为1.5 mg/g、黄酮为1.13 mg/g、多酚为4.33 mg/g、多糖为126.36 mg/g.     

水酶法提取石榴籽油脂肪酸组成与氧化稳定性分析

通过气相色谱-质谱法分析了水酶法提取的石榴籽油的脂肪酸组成。结果表明:石榴籽油含有丰富的不饱和脂肪酸,总不饱和脂肪酸含量达94%以上。采用Schall烘箱法,以过氧化值(POV)为参考指标,研究了光线、温度及抗氧化剂对石榴籽油氧化稳定性能的影响。结果表明,温度、光线对石榴籽油的氧化过程都有影响,温度的影响更为显著;叔丁基对苯二酚(TBHQ)对石榴籽油具有良好的抗氧化效果,并与抗坏血酸(VC)具有较好的协同增效作用;生育酚(VE)和没食子酸丙酯(PG)对石榴籽油无显著抗氧化作用。     

薏苡根不同极性组分的抗氧化活性分析

目的:提取薏苡根有效成分并比较不同组分的抗氧化活性。方法:利用不同极性的溶剂对薏苡根进行提取,并进行显色反应,通过测定薏苡根的铁还原力,总抗氧化能力和对DPPH自由基清除率的测定,从中比较乙酸乙酯,正丁醇和水三个不同极性部位的体外抗氧化活性。结果:乙酸乙酯部位、水部位、正丁醇部位均含有不同程度的体外抗氧化活性物质,且总抗氧化力和铁还原力与浓度之间有相关性,有较好的量效关系。根据各样品的体外抗氧化活性实验可得出各部位所含抗氧化物质的含量或种类:正丁醇提取物水提取物乙酸乙酯提取物。结论:薏苡根各提取部位均具有一定的抗氧化活性,但抗氧化能力不同,其中正丁醇的抗氧化能力最强。     

青钱柳功能性多糖的研究现状及展望

青钱柳叶是一种古老茶饮,也是国家卫健委认定的新食品原料。青钱柳多糖是其主要活性成分之一,具有降血糖、降血脂、抗氧化、免疫调节等多种功能,在食品、医药和生物医学等领域应用市场潜力巨大。通过综述国内外相关研究文献报道,对青钱柳叶所含功能性多糖的提取工艺、结构特征、药理活性及开发应用的研究现状进行较系统的归纳和分析,并对青钱柳多糖未来研究方向作了展望,拟为开发高活性青钱柳多糖保健食品或药物提供理论依据及研究支撑。     

生姜不同有机溶剂提取物的GC-MS分析

用GC－MS方法从生姜的甲醇、乙酸乙酯和正己烷提取中分别鉴定了35、36和44个成分。 显示三种有机溶剂提取物主要成分均为萜类化合物,但萜类含量各不相同：总萜类及倍半萜类成分的含量随提取溶剂极性增大而增多,单萜类成分则随提取溶剂极性增大而减少;具抗氧化活性的不饱和倍半萜成分随提取溶剂性增大而增多,说明了生姜有机溶剂提取物的抗氧化活性随提取溶剂极性增大而增强的原因。     

桦褐孔菌不同提取成分对小鼠免疫功能比较研究

采用正交水提醇沉淀法提取桦褐孔菌成分,得出其最佳提取方法。采用腹腔巨噬细胞吞噬法、测量小鼠免疫器官质量法和测定老龄大鼠SOD酶的活性,研究其对正常小鼠免疫功能的影响及对老龄大鼠抗氧化能力。与乙醇回流提取法和索氏提取法生理盐水组进行比较,得出桦褐孔菌成分可显著提高正常小鼠腹腔巨噬细胞的吞噬功能。通过比较,水提法得到的桦褐孔菌有效成分提高免疫力的作用最强,也证明了桦褐孔菌多糖能通过提高超氧化物歧化酶活性增强老龄大鼠机体的抗氧化能力。     

水稻病毒激光喇曼光谱的初步探讨

本文初步探讨水稻病毒激光喇曼光谱,分析了谱线与病毒中核酸蛋白质结构的关系。确信应用激光喇曼光谱研究水稻病毒是具有信息量大、高灵敏及高分辨本领的。     

WHAT ARE THE CHROMIDIA OF POLYPHAGUS EUGLENAE?

Zoospores, prosporangia, and asexual sporangia were studied with electron microscopy to determine the ultrastructural identification of “chromidia,” granular masses surrounding nuclei that classical mycologists believed to be extruded chromatin used for lipid synthesis. In the zoospore the nucleus was enclosed by an aggregation of ribosomes. In other developmental stages the behavior of microbodies was identical to that described for “chromidia.” A microbody network with interspersed ER surrounded nuclei in young prosporangia. As the prosporangium matured, lipid globules became associated with the microbodies. When the single, large nucleus migrated into the elongate asexual sporangium, microbodies still surrounded the nucleus; but after the nucleus divided and a multinucleate sporangium formed, microbodies were scattered throughout the cytoplasm. When incubated in the diaminobenzidine medium for the cytochemical detection of catalase, reaction product was found in these microbodylike structures, confirming that “chromidia” described in prosporangia and asexual sporangia by classical mycologists are really microbodies. Rather than giving rise to lipid, these microbodies are probably involved in the metabolism of the lipid globules with which they are associated. The “chromidia” in zoospores are not extruded chromatin as suggested earlier, but correspond in their location around the nucleus to an aggregation of ribosomes.     

ARE RECENT DEFENCES OF THE BRAIN DEATH CONCEPT ADEQUATE?

Brain death is accepted in most countries as death. The rationales to explain why brain death is death are surprisingly problematic. The standard rationale that in brain death there has been loss of integrative unity of the organism has been shown to be false, and a better rationale has not been clearly articulated. Recent expert defences of the brain death concept are examined in this paper, and are suggested to be inadequate. I argue that, ironically, these defences demonstrate the lack of a defensible rationale for why brain death should be accepted as death itself. If brain death is death, a conceptual rationale for brain death being equivalent to death should be clarified, and this should be done urgently.     

MEASURES OF PHENOTYPIC SELECTION ARE BIASED BY PARTIAL INBREEDING

When populations are partially inbred due to the population structure or to a mixed mating system like partial self-fertilization, some individuals will be more inbred than others. This heterogeneity among individuals in the history of inbreeding can greatly complicate the interpretation of measures of quantitative genetic variability when the traits studied exhibit inbreeding depression. Partial inbreeding can also bias measures of phenotypic selection toward the detection of strong directional and stabilizing selection. In this paper, data are presented from several inbreeding experiments conducted on two partially selfing, annual populations of the monkeyflower Mimulus guttatus that show that the means of many of the morphological and phenological traits measured were affected by inbreeding. These findings imply that estimates of heritabilities and additive genetic covariances would not reflect the potential for these populations to respond to selection. Phenotypic selection analyses conducted on naturally occurring plants, involving linear regressions of relative seed production on the traits, revealed significant directional selection on many of the same quantitative traits measured in the inbreeding studies. However, when the same selection analyses were performed on plants with known histories of inbreeding, part of the statistical relationship between relative seed number and the traits was found to be due to the mating system: inbred individuals had both lower seed production and different mean values for the traits than outcrossed individuals. It is also shown, with a hypothetical example, that partial inbreeding can bias measures of stabilizing selection toward the detection of strong stabilizing selection. Partial inbreeding therefore tends to make directional and stabilizing selection appear stronger than it is, and it may be that natural selection in the wild is actually weaker than many studies of partially inbred species suggest.     

TWO TYPES OF SENSORY PANELS OR ARE THERE MORE?

The purpose of this article is to discuss the issues associated with selecting assessors for sensory panels. It develops the argument that although there are many variations in the detail of how assessors are selected, all panels can be considered as either (1) selecting respondents to measure ingredient concentrations via perceptions or (2) selecting respondents to represent the response that would be obtained from a wider consumer population. The validity of the data collected, i.e., the extent to which the data collected measures what was originally intended, depends on the detail of how assessors were selected as well as a number of other factors.     

ARE PARALLEL MORPHOLOGIES OF CAVE ORGANISMS THE RESULT OF SIMILAR SELECTION PRESSURES?

The amphipod Gammarus minus is present in both caves and springs, with cave populations showing elaborated (size and antennae) and reduced (eye) characters relative to spring populations. Earlier studies have shown that cave populations resulted from independent invasions of hydrologically isolated subterranean drainages and that there is genetic variation for both elaborated and reduced characters. In this study we tested the hypothesis that a similar pattern of selection on isolated cave populations is responsible for the parallel evolution of cave morphologies. We used variation in mating success and fecundity to test for the presence of directional selection on eye, antennal, and body size characters in a set of cave and spring populations during a series of seasonal cross-sectional samplings. We found significant directional selection for smaller eyes in caves and larger eyes in springs, which supports the hypothesis that selection is responsible for reduced eye size in cave populations. We also found selection for larger body and antennal size in cave populations, which is consistent with the hypothesis that parallel patterns of selection in caves are responsible for the elaboration of body and antennal size. However, we found selection for larger body and antennal size in spring populations that is not consistent with the observed divergence of spring and cave populations. We suggest that unmeasured components of viability selection could be more important in springs than in caves and may act against the selection for larger size found in spring populations.     

ARE POPULATIONS ISLANDS? ANALYSIS OF CHLOROPLAST DNA VARIATION IN AQUILEGIA

The degree to which conspecific populations are interconnected via ongoing gene flow remains an important focus of evolutionary biology. One major difficulty in distinguishing ongoing gene flow from historical subdivision is that either process can generate similar estimates of apparent gene flow. Thus, gene flow estimates themselves are insufficient to distinguish between these alternatives. However, genetic data coupled with additional information about demography and distribution do allow a distinction to be made. Here we address the specific question, does gene flow link populations of Aquilegia? In a survey of a 525 B.P. chloroplast DNA fragment sampled from 251 individual plants from 18 populations of three taxa, five haplotypes were identified. No significant relationship between geographic distance and apparent gene flow between population pairs existed. Further, the estimated level of gene flow was entirely compatible with a historical subdivision of Aquilegia populations during the late Pleistocene or early Holocene. Therefore, these patterns of variation are due not to ongoing gene flow, but rather to historical association among populations. Thus Aquilegia populations may be considered as distinct evolutionary entities with regard to seed-mediated processes. As a result, comparative analysis of ecological traits undergoing potentially rapid evolution (e.g., life histories, mating systems, inbreeding depression) should be possible in these taxa.     

GENETIC COVARIANCE OF FITNESS CORRELATES: WHAT GENETIC CORRELATIONS ARE MADE OF AND WHY IT MATTERS

The genetic variance-covariance matrix, G, is determined in part by functional architecture, the pathways by which variation in genotype influences phenotype. I develop a simple architectural model for G for two traits under directional selection constrained by their dependence on a common limiting resource. I assume that genetic variance is maintained by mutation-selection balance. The relative numbers of loci that play a role in acquiring versus allocating a limiting resource play a crucial role in determining genetic covariance. If many loci are involved in acquiring a resource, genetic covariance may be either negative or positive at equilibrium, depending on the fitness function and the input of mutational variance. The form of G does not necessarily reveal the constraint on resource acquisition inherent in the system, and therefore studies estimating G do not test for the existence of life-history tradeoffs. Characters may evolve in patterns that are unpredictable from G. Experiments are suggested that would indicate if this model could explain observations of positive genetic covariance.     

BUBBLESTREAM WHISTLES ARE NOT REPRESENTATIVE OF A BOTTLENOSE DOLPHIN'S VOCAL REPERTOIRE

Whistling bottlenose dolphins sometimes identify themselves with a concurrent bubblestream, and some researchers use these bubblestream whistles as their sole whistle sample. However, bubblestream whistles are not known to be representative of the entire repertoire. Bubblestreams and whistles were recorded from three captive female dolphins and their newborn calves. Bubblestreams were rare (0.13/min), with calves producing ten times as many as adults. Overall, 79% of bubblestreams were associated with whistles, but only 1 % of whistles were associated with bubblestreams. Bubblestream whistles were not independent: 49% occurred within 1 sec of another bubblestream, and 72% of these had the same contour as other bubblestream whistles in the bout. Bubblestream use was context-dependent: adults were more likely to bubblestream when caring for a calf ( P < 0.001), and calves were more likely to bubblestream when other calves were present ( P < 0.001). Bubblestreams were not associated with all whistle types. Bubblestream whistles were not evenly distributed across the clusters of a hierarchical cluster analysis of contour parameters using 300 randomly selected non-bubblestream whistles and 92 independent bubblestream whistles (10 clusters, P = 0.003). In conclusion, bubblestreams are rare visual cues that dolphins produce in association with certain whistles in certain contexts and are not representative of the dolphin's repertoire.     

OUR BRAINS ARE NOT US

Many neuroscientists have claimed that our minds are just a function of and thus reducible to our brains. I challenge neuroreductionism by arguing that the mind emerges from and is shaped by interaction among the brain, body, and environment. The mind is not located in the brain but is distributed among these three entities. I then explore the implications of the distributed mind for neuroethics.