带3蛋白转运吡啶二羧酸根离子的动力学研究

利用ＤＰＡ使Ｔｂ３＋的荧先强度显著增强的原理进行带３蛋白活性的测定,方法简便、灵敏、重复性好,而且能够进行连续荧光扫描测量．应用连续荧光扫描法测定了带３蛋白介导的ＤＰＡ与Ｃｌ－交换的动力学特征参数．结果表明,带３蛋白介导的ＤＰＡ与Ｃｌ－的交换对ＤＩＤＳ非常敏感,受ＤＩＤＳ的强烈抑制,抑制程度大于９０％;ＤＰＡ由内向外转运的米氏常Ｋｍ＝２８．１—３１．２ｍｍｏｌ／Ｌ;带３蛋白的天然底物Ｃｌ－从内侧竞争性抑制ＤＰＡ向外转运,抑制常数ｋｉ＝６０．４±６．９ｍｍｏｌ／Ｌ;膜内侧ＤＰＡ与外侧Ｃｌ－交换的活化能,在４—２５℃范围内为５．８±０．５ｋＣａｌ／ｍｏｌ２５—３７℃范围内为１９．８±１．５ｋＣａｌ／ｍｏｌ;膜内侧ＤＰＡ与外侧Ｃｌ－交换受转运介质ｐＨ（膜内外对称改变）的显著影响,ｐＨ＜７．４时,交换速度显著升高．本实验证明ＤＰＡ确是经带３蛋白而转运的,但转运机制可能与无机离子转运有所不同。     

有氧运动对高胆固醇血症大鼠肝脏低密度脂蛋白受体活性调节…

本文研究了实验性在醇血症大鼠肝脏低密度脂蛋白受体（ＬＤＬ－Ｒ）活性变化及有氧运动时ＬＤＬ－Ｒ活性调节的影响,发现,高脂（ＨＣ）组肝组织匀浆ＬＤＬ－ＲＩ自古以来生较正常对照（ＮＣ）组降低３７％（Ｐ〈０．０５）,同时血清大醇（ＴＣ）、低密度脂收白胆固醇（ＬＤＬ－Ｃ）及血清栽脂蛋白Ｂ（ＡｐｏＢ）均显著高于ＮＣ组（Ｐ〈０．０１）;高脂＋运动（ＨＥ）组ＴＣ、ＬＤＬ－Ｃ及ＡｐｏＢ均明显低于ＨＣ组,而ＬＤＬ－Ｒ     

模拟鸡胚肝脏液晶类脂滴的体外构建

鸡胚发育肝脏组织中,特定时期大量出现的液晶态类脂滴（ｌｉｑｕｉｄｃｒｙｓｔａｌｌｉｐｏｉｄｄｒｏｐｌｅｔ,ＬＣＬＤ）脂组分主要由卵磷脂、胆固醇和油烯基胆固醇酯等组成。本文中,我们以此三组分在体外进行了模拟构建,结果表明构建的类脂滴具有与ＬＣＬＤ相同的光学织构（马尔它十字）,其冰冻蚀刻复型膜的电镜观察显示其结构也为同心圆片层;构建的类脂滴与鸡胚肝ＬＣＬＤ具有相似的相变特征,经冷冻处理也形成结晶,并在室温下保持这种状态,该结晶的冰刻结构也与胚肝ＬＣＬＤ类似     

有氧运动对高胆固醇血症大鼠肝脏低密度脂蛋白受体活性调节的影响

本文研究了实验性高胆固醇血症大鼠肝脏低密度脂蛋白受体（ＬＤＬＲ）活性变化及有氧运动时ＬＤＬＲ活性调节的影响。发现,高脂（ＨＣ）组肝组织匀浆ＬＤＬＲ活性较正常对照（ＮＣ）组降低３７％（Ｐ＜０．０５）,同时血清总胆固醇（ＴＣ）、低密度脂蛋白胆固醇（ＬＤＬＣ）及血清载脂蛋白Ｂ（ＡｐｏＢ）均显著高于ＮＣ组（Ｐ＜０．０１）;高脂＋运动（ＨＥ）组ＴＣ、ＬＤＬＣ及ＡｐｏＢ均明显低于ＨＣ组,而ＬＤＬＲ活性则较ＨＣ组增高２６％（Ｐ＜０．０５）。结果提示：（１）高胆固醇负荷时细胞可通过下行调节影响ＬＤＬＲ活性;（２）运动可能通过增加对细胞内胆固醇利用和降解,反馈作用于下行调节过程影响ＬＤＬＲ的合成,增加对ＬＤＬＣ摄取而显著改善血脂水平。     

青藏高原毛茛科3种特有植物核型和进化研究

对青藏高原高山冰缘地区毛茛科３种特有植物的核型进行了分析。它们的核型公式（Ｋ）、染色体相对长度组成（Ｃ．Ｒ．Ｌ．）和核型不对称系数（Ａｓ．Ｋ％）分别为：青藏金莲花Ｔｒｏｌｉｕｓｐｕｍｉｌｕｓｖａｒ．ｔａｎｇｕｔｉｃｕｓ：Ｋ（２ｎ）＝６ｍ＋８ｓｍ（２ＳＡＴ）＋２ｓｔ,Ｃ．Ｒ．Ｌ．＝４Ｌ＋４Ｍ２＋４Ｍ１＋４Ｓ,Ａｓ．Ｋ％＝６３．５７,核型属２Ｂ型;甘青乌头Ａｃｏｎｉｔｕｍｔａｎｇｕｔｉｃｕｍ为Ｋ（２ｎ）＝６ｍ＋１０ｓｍ,Ｃ．Ｒ．Ｌ．＝４Ｌ＋８Ｍ１＋４Ｓ,Ａｓ．Ｋ％＝６２．５４,２Ｂ型;单花翠雀花Ｄｅｌｐｈｉｎｉｕｍｃａｎｄｅｌａｂｒｕｍｖａｒ．ｍｏｎａｎｔｈｕｍ为Ｋ（２ｎ）＝６ｍ＋８ｓｍ＋２ｓｔ,Ｃ．Ｒ．Ｌ．＝４Ｌ＋４Ｍ２＋４Ｍ１＋６Ｓ,Ａｓ．Ｋ％＝６４．３４,属３Ｂ型。经同相关近缘种核型资料比较,青藏金莲花核型不对称性和进化程度比金莲花Ｔ．ｃｈｉｎｅｎｓｉｓ低;甘青乌头的核型不对称性和进化程度在其近缘类群（乌头组Ｓｅｃｔ．Ａｃｏｎｉｔｕｍ）已报道的种之内最低;单花翠雀花核型不对称性和进化水平比翠雀组（Ｓｅｃｔ．Ｄｅｌｐｈｉｎａｓｔｒｕｍ）已报道的展毛翠雀花Ｄ．ｋａｍａｏｅｎｓｅｖａｒ．ｇｌａｂｒｅｓｃｅｎｓ、     

中国林蛙乳酸脱氢酶多基因系统及基因间连锁关系的研究

（１）用聚丙烯酰胺凝胶电泳对山西产中国林蛙４个地理群的３３３只林蛙进行了分析,结果表明：中国林蛙的ＬＤＨ由ＬＤＨ－Ａ,ＬＤＨ－Ｂ和ＬＤＨ－Ｃ３个基因决定。ＬＤＨ－Ａ是单态座位,ＬＤＨ－Ｂ和ＬＤＨ－Ｃ均为多态座位,每个多态座位均有两个等位基因。ＬＤＨ－Ｂ与ＬＤＨ－Ｃ呈紧密连锁关系。认为ＬＤＨ－Ｃ是ＬＤＨ－Ｂ的重复产物。（２）热稳定性、尿素处理稳定性及组织特异性研究表明：ＬＤＨ对温度和尿素处理稳定性顺序为Ａ４＞Ｂ’４＞Ｂ４＞Ｃ４。Ａ４在骨骼肌和肝脏等组织中活力最大,Ｂ４在心肌和卵巢中活力最强,ＬＤＨ－Ｃ主要在眼球和卵巢中表达。（３）Ｌｄｈ－ｂ和Ｌｄｈ－ｂ＇在不同地理群间呈差异分布,随着纬度的增高,Ｌｄｈ－ｂ在种群中的频率增大。     

HDL受体和肝性脂酶在肝选择性摄取HDL_2－CE中的协同作用

体外重组３Ｈ－ＣＥ－无ＡｐｏＥ－ＨＤＬ２（ｒＨＤＬ２）保持天然ＨＤＬ２生物活性。大鼠肝窦状隙细胞与ｒＨＤＬ２３７℃培养３ｈ（正常组）;细胞内吞ｃｐｍ为９９５±１４７（ｘ±Ｓ．Ｄ．,ｎ＝２）。细胞进一步９７℃培养２ｈ．释放三氯醋酸（ＴＣＡ）沉淀和ＴＣＡ上清液中ｃｐｍ为７８±３２和１２±９。Ｎ－乙酰咪唑修饰组为３３９±６２、１９±１１和９±５。肝素处理组为５４２±７８、３４±１４和９±８。实验结果提示：（１）肝窦状隙细胞通过ＨＤＬ受体内吞ＨＤＬ２摄取ＨＤＬ２－ＣＥ,并通过逆向胞饮将ＨＤＬ３排出体外．（２）肝性脂酶（ＨＬ）直接介导细胞选择性摄取ＨＤＬ２－ＣＥ,导致ＨＤＬ３生成．（３）ＨＬ和ＨＤＬ受体在介导细胞选择性摄取ＨＤＬ２－ＣＥ中具有协同作用。     

渗透胁迫下玉米幼叶延伸生长与生长部位质膜H~＋─ATPase的关系

－０．４ＭＰａ和－０．８ＭＰａＰＥＧ６０００对玉米幼叶延伸生长和生长部位Ｈ＋分泌有明显的抑制作用,但对生长部位ＰＭＨ＋－ＡＴＰａｓｅ则有不同程度的激活作用,正常水分条件下,Ｎａ３ＶＯ４和ＤＣＣＤ强烈抑制ＬＥＲ和Ｈ＋分泌,抑制程度ＤＣＣＤ＞Ｎａ３ＶＯ４,二者使膜透性增加的程度很相近。－０．４ＭＰａ　ＰＥＧ胁迫下,Ｎａ３ＶＯ４对ＬＥＲ和Ｈ＋分泌的抑制作用不明显,而ＤＣＣＤ仍显著抑制ＬＥＲ和Ｈ＋分泌;ＤＣＣＤ促进膜透性增加的程度远大于Ｎａ３ＶＯ４。     

硒拮抗氟对肾脏损害的酶组织化学观察

本实验以酶组织化学方法（ＳＤＨ、ＬＤＨ、ＡＣＰ、ＡＬＰ）探讨硒对氟引起肾脏损害的拮抗作用。大鼠分为六组,Ａ组常规饮水;Ｂ组饮水含亚硒酸钠２ｍｇ／Ｌ;Ｃ组饮水中含氟化钠１５０ｍｇ／Ｌ;Ｄ、Ｅ、Ｆ组饮水中分别含氟化钠１５０ｍｇ／Ｌ,依次含亚硒酸钠０．５ｍｇ／Ｌ、２ｍｇ／Ｌ、４ｍｇ／Ｌ。８周后断头处死,观察肾脏组织中ＳＤＨ、ＬＤＨ、ＡＣＰ、ＡＬＰ的活性。结果表明,与Ａ组相比,Ｃ组近曲小管ＳＤＨ、ＡＬＰ活性减弱,ＬＤＨ、ＡＣＰ活性明显增加;Ｂ组ＳＤＨ、ＡＣＰ活性正常,基底膜清晰;Ｄ、Ｅ、Ｆ组均能提高ＳＤＨ活性,其中Ｅ组较稳定;Ｆ组ＡＣＰ活性较高。结果说明了氟引起肾近曲小管溶酶体的破坏,而硒（２ｍｇ／Ｌ）能稳定溶酶体膜,拮抗氟对肾脏的损害作用     

1999年普通高等学校招生全国统一考试生物(广东)试题答案及评分标准

一、选择题：本题包括４０小题,每１．５分共６０分。　１．Ｃ　　２．Ａ　　３．Ｄ　　４．Ｄ　　５．Ｂ　６．Ｄ　　７．Ｃ　　８．Ｄ　　９．Ａ　　１０．Ｄ１１．Ａ　　１２．Ｂ　　１３．Ｄ　　１４．Ｄ　　１５．Ｂ１６．Ｂ　　１７．Ａ　　１８．Ｃ　　１９．Ａ　　２０．Ａ２１．Ｄ　　２２．Ｃ　　２３．Ｂ　　２４．Ｃ　　２５．Ｄ２６．Ｂ　　２７．Ｃ　　２８．Ｄ　　２９．Ａ　　３０．Ｂ３１．Ｃ　　３２．Ｄ　　３３．Ｄ　　３４．Ｄ　　３５．Ａ３６．Ｃ　　３７．Ａ　　３８．Ｂ　　３９．Ｄ　　４０．Ｂ二、简答题：本大…     

Factors influencing the levels of fatty acid synthase complex activity in fowl

There is a notable discrepancy between the FAS (fatty acid synthase) activity of four types of fowl (egg chicken, meat chicken, egg duck, and meat duck) with distinctively different body fat levels. There is a 14.8 fold difference per unit body weight between the maximum and minimum FAS activities. The three major factors affecting this discrepancy are liver weight per unit body weight, which is 2.3 times greater in meat ducks than in egg chickens, the amount of FAS protein per gram of liver, which is 1.85 times greater in meat ducks than in egg chickens, and the FAS specific activity in meat ducks, which is 3.5 times greater in meat ducks than in egg chickens. Within the same species of egg chickens, the abdomen fat per kg of body weight at 470 days after egg production is 66 times greater than 90 days before egg production and the liver FAS activity is increased 9.6 fold. The 9.6 fold FAS activity increase resulted from an increase in the specific activity, since the liver weight per kilogram of body weight remained constant at approx. 20 grams and the FAS weight per gram of liver also remained constant at approx. 4.5 mg. This shows that the control of the basic FAS activity level which is closely related to the level of body fat does not mainly arise from genetic control. For the same kind of fowl, the control of the basic FAS activity level occurs after gene expression. It is suggested that control may be imposed in the folding phase when new peptides give rise to functional proteins.     

鸡胚肝脏液晶类脂滴冰冻蚀刻结构研究

鸡胚肝脏组织中液晶类脂滴在不同温度及不同降温速度等条件下,呈现出液晶、结晶及各向同性态,并且三相之间可以互相转变.以冰冻蚀刻复型的方法,证实鸡胚发育中肝脏类滴液晶态为迟晶型液晶,并对0℃处理后的类脂满结晶进行了观察.最后对鸡胚肝脏液晶类脂滴与低密度脂蛋白的相似性进行了讨论.     

Waves of genomic hitchhikers shed light on the evolution of gamebirds (Aves: Galliformes)

Background  

The phylogenetic tree of Galliformes (gamebirds, including megapodes, currassows, guinea fowl, New and Old World quails, chicken, pheasants, grouse, and turkeys) has been considerably remodeled over the last decades as new data and analytical methods became available. Analyzing presence/absence patterns of retroposed elements avoids the problems of homoplastic characters inherent in other methodologies. In gamebirds, chicken repeats 1 (CR1) are the most prevalent retroposed elements, but little is known about the activity of their various subtypes over time. Ascertaining the fixation patterns of CR1 elements would help unravel the phylogeny of gamebirds and other poorly resolved avian clades.     

Cytochrome P450 enzyme activity in five herbivorous,non-passerine bird species

We examined hepatic cytochrome P450 activity in wild and hand-reared grey partridges (Perdix perdix), capercaillies (Tetrao urogallus) and ring-necked pheasants (Phasianus colchicus), as well as the enzyme activity in a variety of tissues of hand-reared Japanese quails (Coturnix coturnix japonica) and pigeons (Columba livia). Post-mortem decrease in hepatic enzyme activity in the grey partridge was measured. Hepatic 7-ethoxyresorufin-O-deethylase activity was similar in wild and hand-reared grey partridges and pheasants, but the activity was significantly lower in wild than in hand-reared capercaillies, probably resulting from their phenolic-rich diet. In the tissues of both quails and pigeons 7-ethoxycoumarin-O-deethylase exhibited the highest and 7-pentoxyresorufin-O-deethylase the lowest activity. Hepatic enzyme activity was significantly higher than that in other tissues. In the small intestine some activity could be found, reflecting some intestinal detoxication capacity. Enzyme activity decreased by 34-69% during the 30-min sampling period, which confirmed the importance of equalising sampling time to obtain comparable data. Because the hand-reared birds in this study were fed the same commercial diets, we assumed that the enzyme activity values detected reflect species differences without any induction by dietary secondary compounds.     

Mechanism of Ice Growth in a Batch Crystallizer with an External Cooler for Freeze Concentration

Two mechanisms of ice crystal growth were found in a batch crystallizer with an external cooler, that contained a large amount of ice crystals. With the first mechanism, the ice crystals grew larger by the usual kind of growth, governed by heat or mass transfer resistance, and with the second, the ice crystals agglomerated and the agglomerate fused into a very large ice crystal (1 ~3mm in diameter). The conditions in which the second mechanism prevails were investigated extensively. The second mechanism occurred not because of the high concentration of ice crystals in the crystallizer but because of long residence time. Large ice crystal agglomerates were not produced when extremely small ice crystals were formed in the crystallizer at the start of the experiment.     

泰和鸡肾小球旁器的观察

本文用光镜和透射电镜对泰和鸡(乌骨鸡)的肾小球旁器进行了观察。结果表明,泰和鸡的肾小球旁器由球旁细胞、过渡型致密斑、球外间膜细胞和极周细胞所组成。极周细胞在鸟类还属首次报道,它位于肾小囊脏层与壁层上皮移行处,环绕着肾小体的血管极,其结构与哺乳动物的相似。本文还就泰和鸡肾小球旁器的结构与功能的关系作了讨论。     

Transformation of macrophages into foam cells in vitro induced by cholesteryl oleate liquid crystals

Transformation of macrophages into foam cells after the uptake of cholesteryl oleate anisotropic liquid crystals was studied. A new technique to enhance the uptake of the liquid crystals by macrophages using an inverted petri dish was developed. Uptake of lipid droplets was found to increase in parallel with the amount of liquid crystals in the medium. A lysosomal enzyme was shown (by using lysosomotropic chloroquine) to be involved in the hydrolysis of the liquid crystals. About 47 and 72% of the [3H]cholesterol in liquid crystal-laden cells had disappeared after chase for 24 and 48 h, respectively. Thus the 50% clearance time of the liquid crystals by the macrophages was about 24 h, which was longer than that of denatured lipoprotein. A possible model of transformation of macrophages to foam cells is discussed.     

Tissue-specific distribution of carotenoids and vitamin E in tissues of newly hatched chicks from various avian species

The aim of this study was to evaluate carotenoid and vitamin E distribution in egg and tissues of newly hatched chicks from wild mallard (Anas platyrhynchos), game pheasant (Phasianus colchicus), free-range guinea fowl (Numida meleagris), hen (Gallus domesticus) and domestic duck (Anas platyrhynchos) and intensively housed hens. Carotenoid concentrations in the egg yolk of free-range guinea fowl, pheasant and wild mallard were similar (61.3-79.2 microg/g). Egg yolks from ducks and intensively housed hens were characterised by the lowest carotenoid concentration comprising 11.2-14.8 microg/g. However, carotenoid concentration in eggs from free-range ducks and hens was less than half of that in free-range guinea fowl or pheasant. Depending on carotenoid concentration in the livers of species studied could be placed in the following descending order: free living pheasant>free-range guinea fowl>free-range hen>intensively housed hen>wild mallard>housed duck>free-range duck. The carotenoid concentrations in other tissues of free-range guinea fowl and pheasant were substantially higher than in the other species studied. Egg yolk of housed hens was characterised by the highest alpha- and gamma-tocopherol concentrations. In accordance with the alpha-tocopherol concentration in the egg yolk, the birds can be placed in the following descending order: intensively housed hen>wild mallard>free-living pheasant>free-range duck>free-range hen=free-range guinea fowl>housed duck. The main finding of this work is species- and tissue-specific differences in carotenoid and vitamin E distribution in the various avian species studied.     

Muscle fat composition of pheasants (<Emphasis Type="Italic">Phasianus colchicus)</Emphasis>, wild ducks (<Emphasis Type="Italic">Anas platyrhynchos</Emphasis>) and black coots (<Emphasis Type="Italic">Fulica atra</Emphasis>)

The aim of this investigation was to characterise the fatty acid composition within intramuscular fat (IMF) of two muscles (breast and thigh) from 28 pheasants, ten wild ducks and 27 black coots from Slovakia. A high variability for all single fatty acids (FA) and the total fat concentration in muscles of wild birds was identified. Black coots deposited the highest fat in breast muscle whereas wild ducks and pheasants accumulated more lipids in thigh muscle. In general, the content of polyunsaturated fatty acids (PUFA) of the IMF in wild bird muscles was high, and the saturated FA concentration was lower compared with muscles of domestic farm animals. The ratio between PUFA and saturated fatty acids (PSQ) ranked between 0.6 and 1.2, and the ratio of n-6/n-3 fatty acid was favourably low in black coot and wild pheasants (3.2 and 2.9, respectively). Farmed pheasants had increased IMF and more saturated and n-6 fatty acids deposited in thigh muscle but not in breast muscle.