胆汁三烯结合蛋白在大肠杆菌中的表达、复性与纯化

目的：合成胆汁三烯结合蛋白（BBP）基因并在大肠杆菌中表达,获得重组BBP纯化制品。方法：根据天然BBP的基因序列和大肠杆菌偏好密码子设计并合成BBP基因的引物,PCR扩增优化的BBP基因序列,克隆至载体pEasy-T3;测序正确后,将该序列克隆至表达载体pET-32a上,构建表达质粒,转化至大肠杆菌BL21（DE3）pLysS,在IPTG诱导下表达融合蛋白;采用Ni柱纯化融合蛋白。结果：PCR扩增获得了优化后的BBP基因序列,构建了表达载体pET-32a-BBP;SDS-PAGE分析表明表达的融合蛋白相对分子质量为20×10^3,以包涵体形式存在,占全菌蛋白的40%以上;变性、复性后经Ni2＋柱纯化,获得纯度达98%以上的重组蛋白。结论：优化并合成了BBP全基因序列,获得了高纯度重组融合蛋白,为进一步鉴定其生物活性及筛选小分子的研究奠定了基础。     

Contractile behavior of the forelimb digital flexors during steady-state locomotion in horses (Equus caballus): an initial test of muscle architectural hypotheses about in vivo function

The forelimb digital flexors of the horse display remarkable diversity in muscle architecture despite each muscle-tendon unit having a similar mechanical advantage across the fetlock joint. We focus on two distinct muscles of the digital flexor system: short compartment deep digital flexor (DDF(sc)) and the superficial digital flexor (SDF). The objectives were to investigate force-length behavior and work performance of these two muscles in vivo during locomotion, and to determine how muscle architecture contributes to in vivo function in this system. We directly recorded muscle force (via tendon strain gauges) and muscle fascicle length (via sonomicrometry crystals) as horses walked (1.7 m s(-1)), trotted (4.1 m s(-1)) and cantered (7.0 m s(-1)) on a motorized treadmill. Over the range of gaits and speeds, DDF(sc) fascicles shortened while producing relatively low force, generating modest positive net work. In contrast, SDF fascicles initially shortened, then lengthened while producing high force, resulting in substantial negative net work. These findings suggest the long fibered, unipennate DDF(sc) supplements mechanical work during running, whereas the short fibered, multipennate SDF is specialized for economical high force and enhanced elastic energy storage. Apparent in vivo functions match well with the distinct architectural features of each muscle.     

Loading the multilayer dextran sulfate/protamine microsized capsules with peroxidase

Stable polyelectrolyte capsules were produced by the layer-by-layer (LbL) assembling of biodegradable polyelectrolytes, dextran sulfate and protamine, on melamine formaldehyde (MF) microcores followed by the cores decomposition at low pH. The mean diameter of the capsules at pH 3-5 was 8.0 +/- 0.2 microm, which is more than that diameter of the templates (5.12 +/- 0.15 microm). With pH growing up to 7-8, the capsules enlarged, swelling up to the diameter 9-10 microm. The microcapsules were loaded with horseradish peroxidase. Seemingly, peroxidase is embedded in the gellike structure in the microcapsule interior formed by MF residues in the complex with polymers used for LbL coating as proved by Raman confocal spectroscopy. The amount of finally incorporated peroxidase increased from 0.2 x 10(8) to 2.2 x 10(8) peroxidase molecules per capsule with pH growing from 5 to 8. The pH shifts causing changes in capsule swelling and the replacement of solutions without pH shifts lead to the protein loss. The encapsulated peroxidase showed a high activity (57%), which remained stable for 12 months.     

男性腿黑激素和N-乙酰-5-羟色胺血浓度的观察

在三个年龄组的中国男性中,对其血液腿黑激素和 N-乙酰-5-羟色胺进行了定量观察。血样本分别于下午4—5时和夜间0—2时,从青春期前、成年和老年三个年龄组采取。分别采用二氯甲烷和甲醇提取血液中的腿黑激素和 N-乙酰-5-羟色胺,用放射免疫法进行测定。实验结果表明,腿黑激素血水平夜间呈节律性的升高,且其血浓度的降低与年龄相关。血液中 N-乙酰-5-羟色胺的水平可能呈昼高夜低的节律性,其血浓度的高低与年龄无关。     

The Somatic Function of the Germ Nucleus in Pseudourostyla cris tat a: Asexual Reproduction and Stomatogenesis

The micronuclei of the ciliated protozoan Pseudourostyla cristata were eliminated by amputation shortly before binary fusion. The amicronucleate cell lines derived from regenerants were maintained for more than a year. They exhibited a lower viability and reduced vigor in asexual propagation. There was some improvement in the growth of the cell lines 1 mo after operation, but the growth rate remained subnormal even up to 1 yr of culture. The exact cause of the poor growth and survival in the first 3 wk after operation, whether the loss of the micronucleus or operational damage, remains to be determined. It is nevertheless clear that the micronucleus is important for subsequent asexual propagation. The amicronucleate cell lines were permanently crippled in morphogenesis, unlike the situation in Paramecium amicronucleates in which stomatogenesis returned to near-normal during asexual propagation. They always included some cells with a characteristically defective adoral zone of membranelles, reduced number of frontal-ventral-transverse cirri, and reduced body length. They were also reluctant to encyst. It is evident that the micronucleus is important for maintaining normality of the oral apparatus. It is postulated that the permanent stomatogenic crippling of amicronucleates might be related to genomic reduction in the developing macronucleus in sexual reproduction, as exhibited by other hypotrichs. The morphological defects associated with the adoral zone of membranelles may be rationalized as arising from the spreading of a zone of degeneration in the cortex affecting the left edge of the membranelles.     

Anomalous Cases of Conjugation and Spontaneous Autogamy in Stylonychia mytilus: A Note on the Asexuality of Early Conjugants

Four types of anomalous conjugation were documented in Stylonychia mytilus. Type I pairs were formed between mates of different sizes. These pairs exhibited an abnormal site of fusion in at least one of the mates, and the mates might face each other ventrally throughout conjugation instead of the normal side-by-side position. Type I pairs underwent sexual nuclear development and proceeded with the first cortical reorganization as in normal conjugants. Type II involved pairing at the anterior ends of mates with ventral surfaces facing the same direction. These pairs also underwent sexual nuclear development. Hence, aberrant orientation of the mates, and also ectopic sites of cytoplasmic fusion, if extensive, would permit sexual development. Type III pairs were united ventral-to-ventral with their anterior-left sides at the adoral zone of membranelles, and remained as such throughout conjugation. In these pairs, nuclear and cortical events were typical of the asexual development of physiological reorganization. In Type IV pairs, one mate of the pair possessed a fission furrow and developed two sets of ciliature typical of binary fission, while the other mate might undergo physiological reorganization or binary fission. Type III and Type IV pairs thus reveal the asexual state of early conjugants, which can pursue either one of the two modes of asexual cortical reorganization; these cases reinforce the notion of overlap of asexual and sexual cycles during conjugation of hypotrichs. Spontaneous autogamy was documented for the first time for this genus. The autogamonts proceeded with nuclear development and with the first cortical reorganization. Some probably underwent second and third reorganizations, as in conjugants, but accompanied by abnormalities, particularly in the stages beyond fertilization. Post-autogamous clones were nonviable except for one dubious case.     

Hysteresis in the response of stomatal conductance in Pinus sylvestris L needles to light: observations and a hypothesis

Abstract. The response of stomatal conductance in Pinus sylvestris L. to a sequence of progressively changed photon flux densities showed hysteresis when the direction of the sequence was reversed. Hysteresis was most evident when 1 h was allowed for stabilization at a temperature of 10°C and a leaf-air vapour pressure difference of 0.5 kPa. The hysteresis was largely eliminated by a stabilization time of 2.5 h or a temperature of 20°C. Elimination of self shading also largely eliminated the hysteresis and resulted in light saturation of stomatal conductance at about 600 μE m⁻² s⁻¹ whereas with the normal grouping of fasicles light saturation was not achieved at 1750 μE m⁻² s⁻¹ even with bilateral illumination. Hysteresis was also eliminated by reduction in the maximum attainable conductance as a result of large leaf-air vapour pressure differences (> 1.8 kPa) but reducing the ambient CO₂ concentration to the compensation concentration or below had no effect on hysteresis. In addition to the hysteresis, there was a carry-over effect of the previous treatment. When the direction of the sequence of photon flux densities was changed, stomatal conductance continued to change in the direction appropriate to the previous sequence for at least 1 h. The presence of a transportable chemical intermediate is postulated, the amount or activity of which would take some time to change after a change in photon flux density. The presence of such an intermediate could account for both the sluggishness of the stomata and the carry over effect. As a result of the sluggish behaviour and carryover, in the field stomatal conductance will tend to follow the general trend in photon flux density and will be very insensitive to short term fluctuations.     

The Concept of Electroosmotically Driven Flow and Its Application to Biomimetics

1　IntroductionOneaimofthephysicsscienceresearchistodevel opfundamentalandportableconceptswhichhelpunitedifferentresearchfrontiers.Inthisrespect ,Helmholtz’selectricdoublelayer (DEL)theory ,whichwasdevel opedin 1879andrelatedtheelectricandflowparame tersforelectrokinetictransport ,isaseminal,havingprovidedaframeworkforinterpretingawiderangeofelectrokineticphenomena .DespitethesimplicityoftheEDLtheory ,whichwewilldescribeindetail,ithasprovidedachallengeformathematicianstounderstanditsimplic…     

犬蝠夜栖息地及夜栖息巢特征的初步研究

<正>大多数种类的蝙蝠不会整个晚上都进行觅食,通常在觅食期间有一段长短不一的时间停留在临时地休息,此为夜栖息行为(Hatfield,1937;Krutzsch,1954;Barbour and Davis,1969;Kunz,1973,1974;Hirshfeld et al.,1977)。蝙蝠在夜栖息地进食(Vaughan,1976;Funakoshi and Maeda,2003)、休息并消化食物(Brigham,1991;Funakoshi and Maeda,2003),甚至社会交流(Kunz,1982;Kunz and Lumsden,2003)。不同种类的蝙蝠     

海南一新记录科——伯乐树科

报道了海南一新记录科,即伯乐树科。这是该科在中国最南端的分布,而且是分布于热带山地雨林中。文章并对其地理分布和保护建议进行了阐述。