荷包牡丹碱和印防己毒素诱发的脊兔膈神经呼吸样电活动

实验用家兔共71只。乌拉坦浅麻醉,麻痹肌肉,颈_1或颈_2 横断脊髓,记录膈神经电活动。43例中,25例出现紧张性电活动,无一例自行恢复呼吸样节律放电。24例于脊髓蛛网膜下腔(i.s.s.)内给荷包牡丹碱(BCL,20μg/10μl—40μg/20μl i.s.s.),13例给印防已毒素(PIC,20μg/20μl,i.s.s.或3—5mg/kgbt i.v.),能诱发出长串的呼吸样放电(串长在0.25s以上)或短串的抽搐样放电(串长在0.1s 以下)。长串放电,按其募集与去募集特点,可分为三型: Ⅰ型,排放频率平均为23.5±2.3串/min(BCL),出现率为58.5%(BCL)或67.7%,(PIC);Ⅱ型,排放频率平均为33.8±4.7串/min(BCL),出现率为39.3%(BCL)或32.3%(PIC);Ⅱ型,排放频率平均为21.3±2.8串/min(BCL),出现率为2.2%(BCL)或3.3%(PIC)。放电持续时间平均为60.0±18.9min(BCL)或42.0±0.8min(PIG)。Ⅰ型和Ⅱ型放电均具呼吸样放电的特点,Ⅰ型和Ⅱ型的出现率共占长串放电的97.8%。本工作提示:脊髓內源性 GABA 系统对脊髓“呼吸”具有紧张性抑制作用。     

利用微秒和微纳秒脉冲电场诱导细胞融合

[目的]以小鼠骨髓瘤(SP2/0)细胞作为实验材料,比较了SP2/0细胞在不同微秒(μs)脉冲和微纳秒(μs/ns)复合脉冲电融合的细胞存活率和融合率,并确定了最优的μs/ns复合脉冲电融合参数。[方法]将SP2/0细胞分别用Hoechst 33342和碘化丙啶(PI)进行染色,分别选取3组μs脉冲和3组μs/ns复合脉冲对染色后的SP2/0细胞进行电融合,通过荧光显微镜观察融合后细胞的存活率和融合率。[结果]对比不同μs和μs/ns复合脉冲电融合存活率和融合率结果得知,μs/ns复合脉冲比μs脉冲电融合效果更好,且电融合参数为2. 5 k V/cm、20μs、1次,10 k V/cm、200 ns、8次时存活率和融合效率相对最好,存活率和融合率分别为88. 5%±6. 2%和80. 1%±2. 6%。[结论]通过采用不同μs和μs/ns复合脉冲电融合比较了SP2/0细胞的存活率和融合效率,结果显示μs/ns复合脉冲电融合参数在2. 5 k V/cm、20μs、1次,10 k V/cm、200 ns、8次时,存活率比μs脉冲电融合提高6. 4%,融合率提高23. 3%,为利用μs/ns复合脉冲研究杂交瘤细胞电融合奠定了基础。     

吸烟对氨氯地平降压疗效及NO、ET-1、baPWV的影响

目的:评价吸烟对氨氯地平的降压疗效以及对内皮功能和baPWV的影响.方法:120例轻中度高血压患者,根据吸烟情况分为吸烟组(n=60)和不吸烟组(n=60),所有患者服用氨氯地平(5 mg,Qd)12周.观察两组患者的降压疗效以及治疗前后NO、ET-1、baPWV的变化.结果:治疗12周后,吸烟组与不吸烟组的降压总有效率分别为53％、60％,两组比较无统计学差异;治疗前吸烟组与不吸烟组NO浓度分别为272.96± 48.62 (μmol/L)、318.42± 44.17 (μmol/L),ET-1浓度分别为432.22± 50.78(μg/L)、342.75± 43.81 (μg/L),baPWV分别为1857.9± 214.2 (cm/s)、1630.3± 110.0 (cm/s),上述指标组间比较均有显著统计学差异(P＜0.01);经治疗后上述指标较治疗前不吸烟组有统计学意义(治疗前后NO 318.42± 44.17 (μmol/L) vs 385.37± 58.45 (μmol/L);ET-1342.75± 43.81(μg/L) vs 258.49± 43.19 (μg/L);baPWV 1630.3±110.0(cm/s)vs 1573.9± 140.4 (cm/s)),而吸烟组无统计学差异(治疗前后NO 272.96± 48.62 (μmol/L) vs 289.87±48.63 (μmol/L);ET-1 432.22±50.78(μg/L)vs 423.31±47.43 (μg/L); baPWV1857.9±214.2(cm/s) vs 1804.5± 226.1 (cm/s)).结论:吸烟对氨氯地平降压疗效无明显影响,但吸烟影响氨氯地平改善内皮功能及baPWV的作用.     

自发性高血压大鼠淋巴微循环功能变化及特点研究

目的:探讨自发性高血压大鼠(Spontaneously hypertensive rats,SHR)肠系膜淋巴微循环并对其特点进行分析。方法:以Wistar大鼠为对照组,SHR为实验组,分别取10只雄性8周龄Wistar大鼠和8周龄SHR(SHR8W)大鼠,麻醉、固定并暴露肠系膜后,在微循环活体显微镜下观察肠系膜微静脉及微淋巴管,并利用Vas-Track自动跟踪测量系统对视频进行定量检测,比较分析自发性高血压大鼠肠系膜白细胞流变学、舒缩速度、舒缩幅度、舒缩时长比等参数的变化。结果:SHR肠系膜白细胞滚动速度明显增加,炎症反应集中体现在30-40μm的微静脉上,与同周龄的Wistar大鼠相比,SHR肠系膜微淋巴管自律运动的相对振幅显著性降低(31.70%±11.70%vs 43.30%±12.40%,P0.05),舒张期的幅度、时长、传播速度分别受到显著性抑制(30.00±16.00μm,13.90±5.30μm/s,2.67±1.30 s versus 46.00±14.00μm,16.70±7.70μm/s,3.24±1.60 s,P0.001,P0.05,P0.001),收缩期的幅度、时长分别下降至34.00±17.0μm、1.04±0.48 s,而与对照组相比,SHR收缩期传播速度代偿性增高(34.60±14.05μm/s vs 32.00±11.30μm/s,P0.05)。结论:SHR肠系膜微淋巴管自律运动出现功能障碍;SHR肠系膜不同管径级别微静脉的分布是呈现不同的特点。     

孟鲁斯特钠咀嚼片在健康人体内药动学和生物等效性

目的:研究两种(仿制新药与市售)孟鲁司特钠咀嚼片在人体内生物等效性。方法:采用单中心、随机、开放、双周期自身交叉试验设计,20名健康男性志愿者分2周期分别口服受试制剂和参比制剂各10 mg,HPLC法测定血浆中孟鲁司特钠咀嚼片的浓度,用DAS2.1.1软件计算人体药动学参数并进行生物等效性评价。结果:受试制剂和参比制剂两药的主要药代动力学参数AUC0-t分别为(17.94±6.19)μg h/ml和(17.37±4.73)μg h/ml,AUC0-∞分别为(18.26±6.16)μg h/ml和(17.64±4.66)μg h/ml,Cmax分别为(5.58±1.95)μg/ml和(5.54±1.65)μg/ml,Tmax分别为(2.03±0.97)h和(1.93±0.69)h,t1/2分别为(1.20±0.17)h和(1.19±0.13)h。受试制剂的平均相对生物利用度为(101.5±6.56)%。结论:受试制剂和参比制剂具有生物等效性。     

HPLC-MS/MS法测定人血浆中草乌甲素的浓度及生物等效性研究(英文)

本文建立了一种快速、高灵敏的HPLC-MS/MS法用于检测人血浆中的草乌甲素浓度。血浆样品采用沃特斯HLB小柱进行固相萃取,汉邦C18色谱柱(150 mm×4.6 mm,5μm)进行分离,流动相为甲醇∶水(85∶15,v/v),水相含10 mmol/L的醋酸铵和0.1%的甲酸。采用ESI源和多反应监测(MRM)的方式进行检测,草乌甲素及内标的反应离子对分别为644.4/584.4和237.2/194.2,草乌甲素血药浓度在0.010～1.0 ng/mL范围内线性关系良好,最低定量限为0.010 ng/mL可以满足口服0.4 mg草乌甲素后血药浓度的检测,日内日间及质控样品精密度及准确度均在允许范围内。本检测方法被成功的应用在中国健康志愿者生物等效性研究中,20名志愿者口服0.4 mg草乌甲素试验制剂和参比制剂后主要药代动力学参数分别如下:Cmax(0.325±0.110),(0.323±0.115)ng/mL;AUC0-16(1.627±0.489),(1.732±0.556)ng.h/mL;AUC0-∞(1.730±0.498),(1.831±0.562)ng.h/mL;t1/2(4.26±0.95),(3.80±0.90)h;Tmax(1.34±0.54),(1.83±0.99)h。     

头孢氨苄胶囊制剂人体生物等效性研究

目的:研究新仿制的头孢羟氨苄胶囊制剂与市场在售的同类制剂在健康人体内的生物等效性。方法:采用随机交叉试验设计,20名健康男性志愿者分别口服受试制剂与参比制剂500 mg,HPLC法测定血浆中头孢氨苄的浓度,用DAS 2.0软件计算药动学参数并进行生物等效性评价。结果:受试制剂和参比制剂两药的主要药代动力学参数,Cmax分别为(18.12±3.17)μg/ml和(21.28±3.77)μg/ml,Tmax分别为(1.09±0.37)h和(1.04±0.33)h,t1/2分别为(1.15±0.22)h和(1.14±0.20)h,AUC0-t分别为(35.43±5.39)μg h/ml和(37.27±4.76)μg h/ml,AUC0-∞分别为(36.68±6.06)μg h/ml和(38.62±5.48)μg h/ml,受试制剂的平均相对生物利用度为(96.50±7.2)%。结论:受试制剂和参比制剂具有良好的生物等效性。     

齐墩果酸通过PPARγ调控人脐静脉内皮细胞抗氧化损伤作用

目的探讨齐墩果酸(OA)对ox-LDL诱导的内皮细胞氧化损伤的作用及其机制。方法实验分组:对照组,ox-LDL模型组,ox-LDL+OA(10μmol/L,20μmol/L,40μmol/L)组,ox-LDL+OA(10μmol/L,20μmol/L,40μmol/L)+GW9662,GW9662单独处理组。采用MTT法检测HUVECs细胞活力;酶联免疫吸附试验法检测HUVECs细胞SOD活力、GSH活力以及MDA含量;活性氧检测试剂盒检测HUVECs细胞ROS水平;Western blot检测HUVECs细胞PPARγ蛋白表达水平,所有指标的检测都进行生物学重复。采用方差分析和两样本t检验进行统计学分析。结果 MTT结果显示,ox-LDL组的细胞存活率为(49.17±0.62)%,OA(10μmol/L、20μmol/L、40μmol/L)预处理后存活率分别为(68.51±1.16)%、(82.64±0.73)%、(92.37±0.13)%,可减弱ox-LDL对HUVECs细胞存活率的降低且呈剂量依赖性关系,差异具有统计学意义(t=24.35,26.18,35.17;P=0.034,0.027,0.008)。本研究还发现,OA对ox-LDL诱导的HUVECs细胞SOD、GSH活性的降低和MDA、ROS水平的增加具有抑制作用且呈剂量依赖关系。ox-LDL组的细胞SOD、GSH、ROS和MDA水平分别为(16.12±0.06)μmol/g、(132.16±2.11)μmol/g、(2.63±0.02)k U/g、(158.12±0.39)%,ox-LDL+OA(10μmol/L)组的细胞SOD、GSH、ROS和MDA水平分别为(10.60±0.14)μmol/g、(108.36±2.05)μmol/g、(2.41±0.21)k U/g、(136.18±1.24)%,ox-LDL+OA(20μmol/L)组的细胞SOD、GSH、ROS和MDA水平分别为(13.28±0.09)μmol/g、(129.58±0.09)μmol/g、(2.26±0.15)k U/g、(126.43±1.51)%,ox-LDL+OA(40μmol/L)组的细胞SOD、GSH、ROS和MDA水平分别为(14.86±0.16)μmol/g、(131.47±0.76)μmol/g、(2.14±0.08)k U/g、(112.39±1.07)%(F=26.38,31.27,56.82,41.16;P=0.005,0.004,0.002,0.003)。Western blot结果显示,OA有效促进HUVECs细胞PPARγ蛋白水平提高。与ox-LDL+OA(20μmol/L)组(65.37±0.15)%比较,ox-LDL+OA(20μmol/L)+GW9662组的细胞活力为(52.89±0.16)%,差异有统计学意义(t=16.47,P=0.035)。进一步发现ox-LDL+OA(10μmol/L)组SOD、GSH、MDA、ROS水平为(10.58±0.13)μmol/g、(102.46±0.06)μmol/g、(2.42±0.08)k U/g、(144.38±2.02)%,oxLDL+OA(10μmol/L)+GW9662组的SOD、GSH、MDA、ROS水平分别为(8.42±0.05)μmol/g、(88.38±0.48)μmol/g、(2.83±0.01)k U/g、(154.41±1.04)%,两组比较差异有统计学意义(t=38.47,39.25,43.69,41.27;P=0.008,0.008,0.006,0.006);ox-LDL+OA(20μmol/L)组SOD、GSH、MDA、ROS水平(13.25±0.05)μmol/g、(122.59±0.33)μmol/g、(2.23±0.16)k U/g、(123.94±0.15)%,ox-LDL+OA(20μmol/L)+GW9662组的SOD、GSH、MDA、RO水平分别为(10.59±0.12)μmol/g、(106.42±0.15)μmol/g、(2.61±0.07)k U/g、(138.12±1.15)%,两组比较差异有统计学意义(t=46.08,38.11,49.35,35.59;P=0.005,0.008,0.004,0.009);oxLDL+OA(40μmol/L)组SOD、GSH、MDA、ROS水平分别为(15.88±0.14)μmol/g、(140.26±1.05)μmol/g、(2.02±0.13)k U/g、(187.52±0.68)%,ox-LDL+OA(40μmol/L)+GW9662组的SOD、GSH、MDA、RO水平(13.65±0.03)μmol/g、(124.61±1.27)μmol/g、(2.49±0.04)k U/g、(126.51±0.73)%,两组比较差异有统计学意义(t=48.04,38.62,45.14,50.13;P=0.004,0.008,0.005,0.002),此外,本研究还发现,抑制PPARγ后,OA抑制ox-LDL诱导的HUVECs细胞的氧化损伤仍存在剂量效应。结论 OA可以通过PPARγ抑制x-LDL诱导HUVECs细胞氧化损伤。     

CdS/ZnS量子点对秀丽隐杆线虫的生物安全性研究

随着工农业的发展,各类材料如纳米材料、重金属材料应用,及其他一些生物质类材料的积累,对生物体的生长发育和繁殖等都有着较明显的生理毒理效应。只有对这些材料的生物效应有了清楚的了解才能正确地使用而避免它对人体产生毒副作用。本试验以秀丽隐杆线虫为研究对象,从生长发育到基因水平,考察了CdS/ZnS量子点对的生物安全性。研究发现CdS/ZnS量子点暴露不仅对秀丽隐杆线虫的体长、头部摆动以及身体弯曲等生物行为有不同程度的抑制作用,而且对线虫细胞毒性相关基因、胁迫相关基因以及细胞生长发育相关基因的表达也有一定的影响。当CdS/ZnS量子点的暴露浓度为3.33 nmol/L,线虫体长、头部摆动以及身体弯曲分别从空白组的(0.64±0.072)mm,(55.94±7.17)次/min和(9.95±2.42)次/20 s降到(0.48±0.099)mm,(15.83±6.76)次/min和(7.72±1.12)次/20 s;而GST-1,daf-21,HSP-16.4等基因表达分别增加了15.33, 19.51和35.01倍。本研究为量子点在应用过程中的生物安全性研究提供理论依据。     

中脑腹侧被盖区微量注射溴隐亭对伏隔核DOPAC含量的影响

本工作在戊巴比妥钠麻醉的SD雄性大鼠上进行。结果表明:左侧腹侧被盖区(VTA)微量注射多巴胺(DA)受体激动剂溴隐亭(2.5μg/0.5μl,n=5)后,用微分脉冲伏安法(DPV)测定同侧伏隔核中多巴胺代谢产物——3、4双羟苯乙酸(DOPAC),峰值明显增高,注后50 min达到对照值的128％(P<0.01),注后80 min达到最高峰,为对照值的143％(P<0.01),作用的持续时间约2 h,在注后180 min恢复到对照值的111％(P>0.05)。左侧VTA预先微量注射SCH23390——一种高选择性的D_1受体阻断剂(2nmol/0.5μl,n=4).40min后再微量注射溴隐亭(2.5μg/0.5μl),同侧伏隔核中DOPAC氧化峰不再增高。结果提示:VTA微量注射溴隐亭可致中脑边缘多巴胺神经元活动增加,而这种增加作用可能是通过D_1受体中介的。     

Evidence that the C-terminus of OprM is involved in the assembly of the VceAB-OprM efflux pump

Although the architecture of tripartite multiple drug resistance (MDR) efflux pumps of Gram-negative bacteria has been well characterized, the means by which the components recognize each other and assemble into a functional pump remains obscure. In this study we present evidence that the C-terminal domain of the Pseudomonas aeruginosa OprM and the α-helical hairpin domain of Vibrio cholerae VceA play an important role in the recognition/specificity/recruitment step in the assembly of a functional, VceAB-OprM chimeric efflux pump. To our knowledge, this is the first evidence directly linking the C-terminal domain of an outer membrane efflux protein to its recruitment during the assembly of a tripartite efflux pump.     

心脑血管疾病大额住院消费统计分析

通过对医院2004-2006年心脑血管疾病大额住院消费(消费大于50000元,以下简称大额消费)病例发病率高的前五种疾病的构成情况、药费、材料费消耗情况进行分析,认为加强大额病例中发病率高的病种的重点管理,是降低医疗费用的有效途径。建议制定常见病大额病种预定额付费方案和审查报销制度;采用适宜技术;控制药费,防止过度医疗,有效地遏制医疗费用的过快增长。     

Studies on the energy coupling sites of photophosphorylation IV. The relation of proton fluxes to the electron transport and ATP formation associated with Photosystem II

1. By using dibromothymoquinone as the electron acceptor, it is possible to isolate functionally that segment of the chloroplast electron transport chain which includes only Photosystem II and only one of the two energy conservation sites coupled to the complete chain (Coupling Site II, observed P/e₂ = 0.3–0.4). A light-dependent, reversible proton translocation reaction is associated with the electron transport pathway: H₂O → Photosystem II → dibromothymoquinone. We have studied the characteristics of this proton uptake reaction and its relationship to the electron transport and ATP formation associated with Coupling Site II.

2. The initial phase of H⁺ uptake, analyzed by a flash-yield technique, exhibits linear kinetics (0–3 s) with no sign of transient phenomena such as the very rapid initial uptake (“pH gush”) encountered in the overall Hill reaction with methylviologen. Thus the initial rate of H⁺ uptake obtained by the flash-yield method is in good agreement with the initial rate estimated from a pH change tracing obtained under continuous illumination.

3. Dibromothymoquinone reduction, observed as O₂ evolution by a similar flash-yield technique, is also linear for at least the first 5 s, the rate of O₂ evolution agreeing well with the steady-state rate observed under continuous illumination.

4. Such measurements of the initial rates of O₂ evolution and H⁺ uptake yield an H⁺/e⁻ ratio close to 0.5 for the Photosystem II partial reaction regardless of pH from 6 to 8. (Parallel experiments for the methylviologen Hill reaction yield an H⁺/e⁻ ratio of 1.7 at pH 7.6.)

5. When dibromothymoquinone is being reduced, concurrent phosphorylation (or arsenylation) markedly lowers the extent of H⁺ uptake (by 40–60%). These data, unlike earlier data obtained using the overall Hill reaction, lend themselves to an unequivocal interpretation since phosphorylation does not alter the rate of electron transport in the Photosystem II partial reaction. ADP, P_i and hexokinase, when added individually, have no effect on proton uptake in this system.

6. The involvement of a proton uptake reaction with an H⁺/e⁻ ratio of 0.5 in the Photosystem II partial reaction H₂O → Photosystem II → dibromothymoquinone strongly suggests that at least 50% of the protons produced by the oxidation of water are released to the inside of the thylakoid, thereby leading to an internal acidification. It is pointed out that the observed efficiencies for ATP formation (P/e₂) and proton uptake (H⁺/e⁻) associated with Coupling Site II can be most easily explained by the chemiosmotic hypothesis of energy coupling.     

Partial purification and properties of Galleria mellonella larvae proteolytic inhibitors acting on Metarhizium anisopliae toxic protease

Gel permeation, preparative isoelectric focusing, and affinity chromatography were used to purify three inhibitors of proteolytic activity from perchloric acid extracts of last instar Galleria mellonella larvae. Electrofocusing experiments revealed three isoinhibitors with different isoelectric points: inhibitor I-1 with p1 of pH 5.6, inhibitor I-2, pH 7.7, and inhibitor I-3 (of small inhibitory activity), pH 8.6. By affinity chromatography on trypsin-Sepharose 4B the I-1 was purified 9.7 ×, but 71.1% of inhibitory activity was lost. Molecular mass of the inhibitory complex was 12,600 Da. I-1 and I-2 are relatively stable to heat at several pHs with minor stability at pH 10. I-1 and I-2 inhibit serine proteases about 2.5 times as much as sulfhydryl proteases. In the same ratio protease P-1 and protease P-2 from Metarhizium anisopliae are inhibited.     

THE DEATH OF BIOETHICS (AS WE ONCE KNEW IT)

Fast forward 50 years into the future. A look back at what occurred in the field of bioethics since 2010 reveals that a conference in 2050 commemorated the death of bioethics. In a steady progression over the years, the field became increasingly fragmented and bureaucratized. Disagreement and dissension were rife, and this once flourishing, multidisciplinary field began to splinter in multiple ways. Prominent journals folded, one by one, and were replaced with specialized publications dealing with genethics, reproethics, nanoethics, and necroethics. Mainstream bioethics organizations also collapsed, giving way to new associations along disciplinary and sub‐disciplinary lines. Physicians established their own journals, and specialty groups broke away from more general associations of medical ethics. Lawyers also split into three separate factions, and philosophers rejected all but the most rigorous, analytic articles into their newly established journal. Matters finally came to a head with global warming, the world‐wide spread of malaria and dengue, and the cost of medical treatments out of reach for almost everyone. The result was the need to develop plans for strict rationing of medical care. At the same time, recognition emerged of the importance of the right to health and the need for global justice in health. By 2060, a spark of hope was ignited, opening the door to the resuscitation of bioethics and involvement of the global community.     

Survival and metabolism of the harpacticoid copepod Thompsonula hyaenae (Thompson) fed on different diatoms

Survival times and oxygen consumption rates have been determined for a benthic harpacticoid copepod, Thompsonula hyaenae (Thompson), when fed different algal diets. Nauplii and adults lived slightly longer on a diet of Navicula sp. than did those fed N. pelliculosa or a mixture of both naviculoid species. Mean numbers of harpacticoids hatched were significantly higher in cultures of N. pelliculosa. Metabolic rates of non-gravid females fed for one week on N. sp. were significantly lower than those fed N. pelliculosa or the mixture. There was no significant difference in oxygen uptake between animals fed N. pelliculosa and those fed the mixed culture. The smaller size and lower food energy content of N. pelliculosa are reflected in the higher respiratory rates of animals led this diatom species.Based on a thesis submitted in partial fulfillment of the M.S. degree in Marine Science at the University of South Carolina. Belle W. Baruch Institute for Marine Biology and Coastal Research Contribution No. 114. Research supported by the Oceanography Section, National Science Foundation, NSF Grant DES72-01573 A01.     

Strategy for Stabilizing Enzymes Part Two: Increasing Enzyme Stability by Selective Chemical Modification

The molecular mechanisms of change in the thermal stability of proteins modified with low molecular weight reagents are discussed. The choice of stabilization mechanisms to be used as a general strategy for increasing enzyme stability by chemical modification is addressed. Hydrophilization of nonpolar surface areas is the most simple and reliable approach to artificial stabilization of enzymes for use in applied biochemistry and biotechnology.     

Primeval cells: Possible energy-generating and cell-division mechanisms

Summary It is proposed that the first entity capable of adaptive Darwinian evolution consisted of a liposome vesicle formed of (1) abiotically produced phospholipidlike molecules; (2) a very few informational macromolecules; and (3) some abiogenic, lipid-soluble, organic molecule serving as a symporter for phosphate and protons and as a means of high-energy-bond generation. The genetic material had functions that led to the production of phospholipidlike materials (leading to growth and division of the primitive cells) and of the carrier needed for energy transduction. It is suggested that the most primitive exploitable energy source was the donation of 2H⁺+2e^– at the external face of the primitive cell. The electrons were transferred (by metal impurities) to internal sinks of organic material, thus creating, via a deficit, a protonmotive force that could drive both the active transport of phosphate and high-energy-bond formation.This model implies that proton translocation in a closed-membrane system preceded photochemical or electron transport mechanisms and that chemically transferable metabolic energy was needed at a much earlier stage in the development of life than has usually been assumed. It provides a plausible mechanism whereby cell division of the earliest protocells could have been a spontaneous process powered by the internal development of phospholipids. The stimulus for developing this evolutionary sequence was the realization that cellular life was essential if Darwinian survival of the fittest was to direct evolution toward adaptation to the external environment.     

用离散量的方法识别蛋白质的超二级结构

用离散量的方法,对2208个分辨率在2.5I以上的高精度的蛋白质结构中四类超二级结构进行了识别。从蛋白质一级序列出发,以氨基酸(20种氨基酸加一个空位)和其紧邻关联共同为参数,当序列模式固定长取8个氨基酸残基时,对“822”序列模式3交叉检验的平均预测精度达到78.1%,jack-knife检验的平均预测精度达到76.7%;当序列模式固定长取10个氨基酸残基时,对“1041”序列模式3交叉检验的平均预测精度达到83.1%,jack-knife检验的平均预测精度达到79.8%。