Localization of heart poisons in the monarch butterfly

The cardiac glycosides that monarch butterflies sequester from milkweed plants during the larval stage differ remarkably in their emetic potency and are concentrated to different degrees in the various parts of the body as well as in the two sexes (Fig. 1). The very high concentrations of these compounds in the wings probably facilitate learned taste rejection in predators and account for the relatively high frequency of Danaid butterflies with beak-marked wings in natural populations. The cardiac glycosides in the abdomen have a much higher emetic potency than those in the rest of the body. Consequently, naive, extremely hungry, or forgetful birds which capture and peck off the wings but eat the abdomen discard the least emetic glycosides and ingest the most emetic, and thus again experience emesis. The nonrandom distribution of cardenolides in the wings, abdomen, and thorax, together with the fact that monarch males not only contain lower concentrations of cardiac glycosides than females but also contain cardenolides that are overall less emetic than those in females, is interpreted as evidence that these poisons are incorporated at a physiological cost. This cost, balanced against the benefits of protection from predation, provides a selective basis for the occurrence of both emetic and nonemetic individuals in natural populations. Since birds can discriminate emetic from nonemetic monarchs on the basis of taste, it is not necessary to invoke theories of kind of group selection to explain the evolution of this kind of unpalatability.     

Variation in cardiac glycoside content of monarch butterflies from natural populations in eastern North America

A new spectrophotometric assay has been used to determine the gross concentration of cardiac glycoside in individual monarch butterflies. Adults sampled during the fall migration in four areas of eastern North America exhibited a wide variation in cardiac glycoside concentration. The correlation between spectrophotometrically measured concentrations and emetic dose determinations supports the existence of a broad palatability spectrum in wild monarch butterflies. The cardiac gylcoside concentration is greater in females than in males and is independent of the dry weight of the butterflies; contrary to prediction, both the concentration mean and variance decrease southward. The defensive advantage of incorporating cardiac glycosides may be balanced by detrimental effects on individual viability.     

竹笋适口性形成及其主要影响因素研究综述

竹笋是中国传统森林蔬菜，也是大宗出口农产品。适口性体现了竹笋经济价值和市场潜力，是高品质竹笋评价的重要指标，但竹笋适口性形成基础及提升技术研发相对薄弱，一定程度上限制了竹笋品质改良技术研发及生产应用。本研究综述了竹笋适口性评价的主要指标，总结了当前竹笋适口性的主要研究成果，并对未来研究提出展望。目前竹笋适口性的研究主要集中于:①竹笋适口性的种间差异；②环境因子对竹笋适口性的影响；③经营措施对竹笋适口性的影响。主要结论为:糖、酸、酚类、纤维类以及氨基酸类物质是竹笋适口性评价的主要指标，适口性的形成不仅取决于竹种自身遗传因素，同时也受到气候因素和土壤质地等的影响。通过覆盖栽培、施肥、林分结构调控和选择适宜的采笋时间等途径可以改良竹笋适口性，但其效应存在明显的种间差异。未来竹笋适口性的研究应该集中于构建适口性综合评价指标与方法，探究多因素互作对竹笋适口性的影响，从生态、生理、生化、分子等多学科层面揭示竹笋适口性形成机制。筛选适口性好、产量高、生态适应性强的优良笋用竹进行规模化栽培，并从栽培环境选择、土壤养分精准补充、笋芽萌发环境控制、竹笋器官处理等途径研发竹笋适口性改良技术。参66     

Carac glycosides and distastefulness: some observations on the palatability spectrum of butterflies

The monarch butterfly Danaus plexippus sequesters cardiac gylcosides from northern species of Asclepias formerly reported to lack these noxious compounds. Thus, a new explanation must be sought as to why the monarchs reared on these northern asclepiads are palatable to avian predators.     

肉果秤锤树化学成分的预试及生物碱含量的测定

利用植物中的有机成分与专属试剂发生显色反应的原理,采用试管和滤纸片预试法对肉果秤锤树技叶中一些常见种类的化学成分进行预试.结果表明,秤锤树枝叶中可能含有生物碱、有机酸类、酚类、还原糖、多糖、甙类、甾体及三萜类、强心甙、蒽醌、挥发油等有机成分.并采用索氏提取法,以咖啡因为对照对肉果秤锤树枝和叶中总生物碱进行了含量测定.     

裂盖马鞍菌化学成分初步研究

以新疆特色食用菌裂盖马鞍菌为材料,用系统化学预试法对裂盖马鞍菌中的化学成分进行了初步研究。结果表明:裂盖马鞍菌中含有氨基酸、蛋白质、糖及其甙类、生物碱、甾醇、香豆素、强心苷等各类化学物质,是一种具有开发价值的食药用菌。     

The effects of enriched carbon dioxide atmospheres on plant--insect herbivore interactions

Little is known about the effects of enriched CO(2) atmospheres, which may exist in the next century, on natural plant-insect herbivore interactions. Larvae of a specialist insect herbivore, Junonia coenia (Lepidoptera: Nymphalidae), were reared on one of its host plants, Plantago lanceolata (Plantaginaceae), grown in either current low (350 parts per million) or high (700 ppm) CO(2) environments. Those larvae raised on high-CO(2) foliage grew more slowly and experienced greater mortality, especially in early instars, than those raised on low-CO(2) foliage. Poor larval performance on high-CO(2) foliage was probably due to the reduced foliar water and nitrogen concentrations of those plants and not to changes in the concentration of the defensive compounds, iridoid glycosides. Adult pupal weight and female fecundity were not affected by the CO(2) environment of the host plant. These results indicate that interactions between plants and herbivorous insects will be modified under the predicted CO(2) conditions of the 21st century.     

恒温和波动温度下西花蓟马的实验种群生命表

【目的】对西花蓟马（Frankliniella occidentalis）实验种群生命表的研究大多在恒温条件下进行,研究结果可用于田间自然条件下种群发生的预测。然而,西花蓟马在自然界中接触的不是恒温,而是昼夜波动的温度。论文旨在比较恒温和昼夜波动温度下西花蓟马实验种群的生命表参数,探讨用恒温构建的西花蓟马生命表结果来预测自然条件下蓟马种群发生动态的准确性。【方法】分别在恒温（26℃）和均温相同的昼夜波动温度（20-32℃）条件下,构建西花蓟马实验种群在菜豆豆荚上的年龄-阶段特异生命表,比较2种温度条件下西花蓟马的生活史和种群参数。因为卵的孵化率随着成虫年龄变化,所以根据孵化卵的数量来计算年龄-特异繁殖率,以准确揭示西花蓟马的生物学特性。用bootstrap方法来计算种群生长参数的平均数和标准误;用U检验（Mann-Whitney test）（Sigmaplot 12.0）估计恒温和波动温度下西花蓟马种群参数、发育历期和繁殖力间的差异。【结果】恒温和波动温度对西花蓟马的成虫前期发育历期、总产卵前期、成虫前期存活率以及生命表参数等有明显影响（P<0.05）,而对成虫寿命和繁殖力等影响不显著。西花蓟马成虫前期发育历期在恒温（11.86 d）下显著长于在波动温度（11.36 d）下。总产卵前期在恒温与波动温度下分别为12.50和11.37 d,达到显著差异水平。成虫前期在恒温下存活率（0.48）显著高于波动温度下存活率（0.44）。西花蓟马成虫寿命在恒温（雌虫13.56 d,雄虫10.15 d）和波动温度（雌虫11.37 d,雄虫9.71 d）下无显著差异。西花蓟马繁殖力在恒温（35.38卵/雌）和波动温度（34.74卵/雌）下无显著差异。内禀增长率（r）、周限增长率（λ）和净增殖率（R0）在恒温下分别为0.121/d、1.129/d和7.538,在波动温度下分别为0.127/d、1.135/d和8.831。西花蓟马在波动温度下的种群增长要比在恒温下快。【结论】与自然的昼夜波动温度条件相比,恒温可能过高或过低的估计了许多生命表参数,从而影响种群动态监测结果及其在害虫综合治理中的应用。     

杠柳根皮化学成分及杀虫活性的初步研究

采用试管预试和圆形滤纸层析预试法,对杠柳根皮的化学成分进行了初步研究.结果表明,杠柳根皮中含有氨基酸、糖及其苷类、有机酸、皂苷、生物碱、酚类、强心苷类、内酯、香豆素及其苷类、甾醇、三萜类、挥发油、油脂等多种化学成分,其中生物碱类为首次检测到.同时对杠柳根皮的甲醇粗提物,经石油醚、乙酸乙酯、正丁醇及水等不同极性溶剂进行萃取浓缩,选用麦二叉蚜、粘虫为测试对象,对其萃取物进行杀虫活性初步测定,结果表明杠柳根皮的正丁醇提取物对麦二叉蚜有较强的触杀活性,对粘虫有一定胃毒活性.     

笼养和地面平养方式下卢氏鸡胃肠道生长发育规律比较

研究卢氏鸡在笼养和地面平养方式下胃肠道的生长发育情况.选用1日龄健康卢氏鸡公雏240只,随机分成2个处理组,每组120只,设6个重复,其中一个处理组笼养,另一个处理组地面平养.测定肝脏、腺胃、肌胃、胆囊、胰腺、十二指肠、空肠、回肠的质量,计算相对体质量,以及小肠总长度、十二指肠、空肠、回肠长度和相对小肠总长长度指数.结果表明:① 21和42日龄时,笼养组胰腺、十二指肠、空肠、回肠的质量和相对体质量指数都比地面平养组的高,但两组间无显著性差异(P＞0.05);②21和42日龄时,地面平养组肝脏、腺胃、肌胃、胆囊的质量和相对体质量指数都比笼养组高,两组之间差异不显著(P＞0.05);③ 21日龄和42日龄时,笼养组十二指肠、空肠、回肠相对小肠总长长度指数都比地面平养组的高,但两组间无显著性差异(P＞0.05).     

农牧交错区植被特征及多样性对干扰的响应研究

对不同干扰梯度下的植被特征、土壤含水量、重要值和多样性等指标进行比较分析。结果表明:随着干扰程度的加大,多年生植物的种类不断减少,植物适口性以中度干扰为最高;植被的盖度、高度及密度均是中度干扰>重度干扰>轻度干扰,生物量调查结果是重度干扰>中度干扰>轻度干扰;中度干扰和重度干扰的主要优势种重要值分布相对均匀,而轻度干扰下只是极少数几个物种有较高的重要值;多样性结果显示:中度干扰>轻度干扰>重度干扰,表明进行围封的同时进行适当的放牧干扰,才更有利于研究区植被朝多样化方向发展。综合以上分析,中度干扰(半封育措施)显然是农牧交错区植被恢复的最好方式。     

Diet-induced head allometry among foliage-chewing insects and its importance for graminivores

Individuals of the grass-feeding caterpillar of Pseudaletia unipuncta, reared from hatching on hard grass, had head masses twice as great as those of caterpillars fed soft artificial diet, even though the larvae reached the same body mass. Larvae reared on soft wheat seedlings had intermediate head masses. Thus muscular effort increases muscular development in an insect, which in turn has a dramatic morphogenetic effect on head size. Size differences in the head capsules, with the correlated differences in mandibular power, have a direct effect on the ability of the insects to ingest hard foods rapidly: larger heads are adaptive for dealing with hard grasses.     

大叶胡颓子根和茎化学成分预试的对比研究

采用化学成分系统预试法及纯化水、石油醚及95％乙醇三种提取方法,通过多种指示剂和显色剂的沉淀反应或颜色反应,对大叶胡颓子根、茎可能含有的化学成分进行了初步对比研究。结果表明,大叶胡颓子根、茎中均含有三萜类（或甾体）、糖及苷类、有机酸、蛋白质、氨基酸、皂苷、甾体和强心苷等化学成分;根中无法确定是否存在黄酮,而茎的黄酮反应明显;根中未检测到葸醌、香豆素与萜类内酯,而茎的反应比较明显。说明大叶胡颓子根与茎含有多种药理活性成分,但在成分类型及含量上存在着差异。     

拟南芥山奈酚糖苷对UV-B辐射的响应

以拟南芥(Arabidopsis thaliana)为材料,通过施加低强度(40μw·cm-2)和相对长时间(7 d)的UV-B辐射,研究拟南芥幼苗和成苗中三种山奈酚糖苷即山奈酚-3-O-鼠李葡萄糖基-7-O-鼠李糖苷(K1)、山奈酚-3-O-葡萄糖基-7-O-鼠李糖苷(K2)、山奈酚-3-O-鼠李糖基-7-O-鼠李糖苷(K3)含量及合成途径关键酶编码基因表达水平对UV-B辐射的响应.结果表明,拟南芥幼苗三种山奈酚糖苷含量均为成苗的10倍左右.经过7 d的UV-B辐射处理,拟南芥幼苗中山奈酚糖苷积累水平、合成途径关键酶编码基因chs和fls1的相对表达量均显著高于对照植株,山奈酚糖苷表现为响应UV-B辐射而积累.在拟南芥成苗和幼苗中三种山奈酚糖苷组合模式应对UV-B辐射的变化并不一致,这与其在防御机制中的不同角色有关     

猎物种类对东亚小花蝽生长发育繁殖的影响

 【目的】寻找东亚小花蝽Orius sauteri规模化饲养的饲料来源。【方法】用腐食酪螨、朱砂叶螨和桃蚜在17.5、22.5、27.5℃,RH70%下饲养东亚小花蝽,并组建生命表。【结果】腐食酪螨饲养的东亚小花蝽若虫70%-80%能发育为成虫,与桃蚜饲养没有显著差异,但显著高于朱砂叶螨饲养的（低于50%）;在17.5℃下,该猎物饲养的东亚小花蝽没有产卵,净生殖率Ro为0,用朱砂叶螨和桃蚜饲养时其净生殖率Ro分别为1.18和1.09;在22.5℃时用腐食酪螨、朱砂叶螨和桃蚜饲养的东亚小花蝽的净生殖率Ro分别为12.86、15.93和6.11,三种猎物均可完成小花蝽的世代增殖;在27.5℃时用腐食酪螨、朱砂叶螨和桃蚜饲养的东亚小花蝽的净生殖率Ro分别为0.88、3.02和21.70,腐食酪螨饲养的东亚小花蝽的内禀增长率为负数。【结论】腐食酪螨可以作为东亚小花蝽若虫阶段的规模化饲养的饲料。     

Sources of human psychological differences: the Minnesota Study of Twins Reared Apart

Since 1979, a continuing study of monozygotic and dizygotic twins, separated in infancy and reared apart, has subjected more than 100 sets of reared-apart twins or triplets to a week of intensive psychological and physiological assessment. Like the prior, smaller studies of monozygotic twins reared apart, about 70% of the variance in IQ was found to be associated with genetic variation. On multiple measures of personality and temperament, occupational and leisure-time interests, and social attitudes, monozygotic twins reared apart are about as similar as are monozygotic twins reared together. These findings extend and support those from numerous other twin, family, and adoption studies. It is a plausible hypothesis that genetic differences affect psychological differences largely indirectly, by influencing the effective environment of the developing child. This evidence for the strong heritability of most psychological traits, sensibly construed, does not detract from the value or importance of parenting, education, and other propaedeutic interventions.     

槲皮素糖苷类化合物的合成及其对α-葡萄糖苷酶的抑制活性

以芦丁为原料合成了6个槲皮素糖苷类化合物,并经MS,~1H NMR及~(13)C NMR确证其结构。以阿卡波糖为阳性对照测试目标产物对α-葡萄糖苷酶的抑制活性,发现当该类化合物中糖基上的羟基被苯甲酰化后能增强其对α-葡萄糖苷酶的抑制活性,其中V-b和V-c的IC50各为19.4μmol/L,21.5μmol/L,而未被苯甲酰化的化合物VI-b和VI-c的抑制活性相对较低。这将为该类化合物在降糖活性方面的深入研究提供参考。     

Sodium current-induced release of calcium from cardiac sarcoplasmic reticulum

The role of sodium-calcium exchange at the sarcolemma in the release of calcium from cardiac sarcoplasmic reticulum was investigated in voltage-clamped, isolated cardiac myocytes. In the absence of calcium entry through voltage-dependent calcium channels, membrane depolarization elicited release of calcium from ryanodine-sensitive internal stores. This process was dependent on sodium entry through tetrodotoxin-sensitive sodium channels. Calcium release under these conditions was also dependent on extracellular calcium concentration, suggesting a calcium-induced trigger release mechanism that involves calcium entry into the cell by sodium-calcium exchange. This sodium current-induced calcium release mechanism may explain, in part, the positive inotropic effects of cardiac glycosides and the negative inotropic effects of a variety of antiarrhythmic drugs that interact with cardiac sodium channels. In response to a transient rise of intracellular sodium, sodium-calcium exchange may promote calcium entry into cardiac cells and trigger sarcoplasmic calcium release during physiologic action potentials.     

紫色甘薯引进筛选与开发利用

对供试18个紫色甘薯品种的主要农艺性状观察、营养品质鉴定以及加工品质和适应性进行系统分析和比较.结果显示:薯形美观,食味品质和适口性好的4个品种--福薯9号、F22-158、58009和济薯18,适合作为紫色优质食用薯开发;产量高、烘干率与出粉率适中、加工品质好的伟祥1号和济薯18适合作紫色地瓜干加工用原料薯开发;其他...     

上海和韩国粳稻品种米质特性比较

利用6个上海粳稻品种和9个韩国粳稻品种进行了品质特性比较分析。结果表明,上海和韩国品种间的粒宽、长宽比、穗着粒密度、直链淀粉含量、蛋白质含量和碱消值均呈显著的差异,上海水稻品种比韩国水稻品种粒型较细长,穗着粒密度高,直链淀粉含量、蛋白质含量和碱消值高,但食味值和淀粉谱特性则相反,韩国水稻品种的食味值和淀粉谱特性中的最高粘度值、最终粘度值和下降粘度值显著高于上海水稻品种。水稻品质特性间相关分析结果表明,食味值与直链淀粉含量,蛋白质含量和穗着粒密度呈极显著负相关,而与最高粘度值和下降粘度值呈显著的正相关。直链淀粉含量和蛋白质含量与最高粘度值、最低粘度值和最终粘度值均呈极显著的负相关。由此认为,通过育种手段降低直链淀粉含量和蛋白质含量,改进穗型和粒型结构,并在栽培措施上降低氮肥施用量是提高上海水稻品质的有效途径。