鉴别旋幽夜蛾雌雄蛹的方法

报道1种根据旋幽夜蛾Scotogramma trifolii Rottemberg蛹腹节的外部形态特征迅速、准确区分旋幽夜蛾蛹雌雄的方法。雌蛹第8腹节腹面中央有一纵裂缝,裂缝连接第7、第9腹节,裂缝两侧平坦,无突起,腹部末端分节不明显;雄蛹第8腹节无裂缝,在第9腹节腹面中央有一纵裂缝,裂缝两边各有一半圆状瘤状突起,腹部末端分节较为明显。这对于了解旋幽夜蛾田间性比,观察生物学特征、种群动态及开展预测预报等十分重要。     

一种鉴别菜粉蝶蛹雌雄的方法

报道1种根据外部形态特征迅速、准确区分菜粉蝶PierisrapaeL.蛹雌雄的方法。实体显微镜检表明,雌蛹第8腹节有1生殖孔,第9腹节有1产卵孔,两孔之间连成1条长纵裂缝;而雄蛹只在第9腹节有1个生殖孔,形成的纵裂缝短。     

A theoretical method for distinguishing between soluble and membrane proteins

A method for distinguishing between membrane and soluble proteins in an amino acid sequence was developed, using only two parameters associated with the hydrophobicity: the average hydrophobicity and the power spectral density of period longer than 30 residues. The power spectral density was calculated by a maximum entropy method of Fourier transformation. Membrane proteins could be distinguished from soluble proteins with a distinction rate as high as 97%. This fact strongly suggests that the morphology of proteins, i.e., membrane or soluble forms, is determined thermodynamically through the hydrophobicity of polypeptides.     

A method for quantitation of protein in the presence of Percoll

An electromagnet was modified for measurements of the magnetic circular dichroism of samples held at cryogenic temperatures using a standard laboratory cryostat. The external dimensions of the cryostat are too great to permit its insertion in the air gap between the poles of the magnet without an unacceptable reduction in the strength of the magnetic field at the sample. This problem was overcome by designing new pole caps which become an integral part of the vacuum system of the cryostat. The ends of the new pole caps project into the body of the cryostat so that the gap between them is 1 in. or less, thus achieving a magnetic field exceeding one Tesla at the sample. No permanent alterations of the cryostat are required. The chief advantages of this design are economy and flexibility since a general purpose cryostat is used instead of a special unit designed to fit in the small space between the poles of an unmodified magnet. The cryostat used in this design cools the sample by conduction; thus the problem of optical distortions resulting from bubbling of liquid nitrogen or other cryogen is avoided and the temperature can be varied continuously using standard auxiliary equipment. Extra windows at 90° with respect to the optical beam permit inspection of the sample in situ and could be used for experiments such as fluorescence-detected magnetic circular dichroism which require optical access perpendicular to the direction of the magnetic field.     

I-DIRT, a general method for distinguishing between specific and nonspecific protein interactions

Isolation of protein complexes via affinity-tagged proteins provides a powerful tool for studying biological systems, but the technique is often compromised by co-enrichment of nonspecifically interacting proteins. We describe a new technique (I-DIRT) that distinguishes contaminants from bona fide interactors in immunopurifications, overcoming this most challenging problem in defining protein complexes. I-DIRT will be of broad value for studying protein complexes in biological systems that can be metabolically labeled.     

A simplified method for the purification of riboflavin-binding protein from hen's egg yolk

A simple and efficient procedure for the purification of the riboflavin-binding protein from hen's egg yolk is described. This method involves the removal by exclusion of lipoproteins and subsequent fractionation of soluble yolk proteins held on a DEAE-cellulose column by a salt gradient which is followed by purification by gel filtration on Sephadex G-100. The protein thus isolated is homogeneous by various physicoehemical, immunological, and functional criteria.     

A proteolytic method for distinguishing between lipid-free and lipid-bound apolipoprotein A-I

Recent studies indicate that certain lipid-poor forms of apolipoprotein (apo)A-I may be particularly important in promoting cholesterol release from overburdened cells in the periphery. However, a detailed understanding of the physiological relevance of these species has been hampered by the difficulty in measuring them. As part of a search for a rapid assay for these forms of apoA-I, we have observed that the protease enteropeptidase can specifically cleave human lipid-free apoA-I but not its lipid-bound form. Enteropeptidase cleaved lipid-free apoA-I at a single site at amino acid 188, resulting in an N-terminal fragment of 22 kDa. However, apoA-I was not susceptible to enteropeptidase when present in reconstituted high-density lipoprotein (rHDL) particles as small as 6 nm in diameter or in human HDL(3) particles, even at extremely high enzyme-to-protein ratios and extended reaction times. We capitalized on this observation to develop an assay for the measurement of lipid-poor apoA-I in in vitro systems. Densitometry was used to generate a standard curve from sodium dodecyl sulfate polyacrylamide gels to determine the amounts of the N-terminal proteolytic fragment in unknown samples treated with enteropeptidase. This system could accurately quantify apoA-I that had been displaced from rHDL particles and human HDL(3) with purified apoA-II. On the basis of the results, a system of nomenclature is proposed for "lipid-free," "lipid-poor," and "lipid bound" apoA-I.The reported method distinguishes forms of apoA-I by a conformational parameter without previous separation of the species. This simple and inexpensive method will be useful for understanding the characteristics of plasma HDL that are favorable for the dissociation of apoA-I.     

A method for the quantification of bacterial protein in the presence of Jarosite

A variation on Peterson's modification of the Lowry method for microbial protein determination was developed in which 10% (w/v) oxalic acid was used to remove jarosite. This allowed the quantification of Thiobacillus ferrooxidans entrapped in solid jarosite or in aqueous suspensions containing jarosite. The quantity of protein measured was not affected by the amount of jarosite in the culture, the concentration of oxalic acid, or the time of exposure (up to 72 h) of the sample to oxalic acid. An application of this method was demonstrated in the quantification of biomass immobilized in jarosite on the surface of polystyrene beads in an inverse fluidized bed bioreactor used for the rapid microbial oxidation of ferrous iron.     

小体鲟卵黄蛋白生化特性及合成途径的研究

使用葡聚糖凝胶（Sephadex G-200）从小体鲟鱼卵粗提液中,提纯卵黄脂磷蛋白(Lipovitellin, Lv )和卵黄高磷蛋白(Phosvitin, Pv)。卵黄脂磷蛋白（含糖、磷和脂,等电点7.50）具有雌性特异性, 分子量为144 kD,由97.4 kD和30 kD的大小2个亚基组成。卵黄高磷蛋白（含糖、磷,等电点8.30）其分子量为66 kD,其具有两个亚基,分子量分别为47.6 kD、16.8 kD。制备卵黄脂磷蛋白兔抗血清,采用免疫组化方法对不同年龄小体鲟的肝脏、肠、卵（Ⅱ-Ⅴ期卵巢）及血涂片,进行免疫组织化学定位研究。小体鲟卵巢发育到 Ⅳ期前,卵黄蛋白主要靠卵母细胞自身合成,这个时期内源性合成卵黄蛋白;当卵巢发育到 Ⅳ期,卵母细胞自身不合成卵黄蛋白,主要是通过肝脏合成卵黄蛋白原,通过血液循环运送到卵巢,被卵母细胞吸收后,裂解为卵黄蛋白,这个时期外源性合成卵黄蛋白。     

Comparative study of some haematological and biochemical blood parameters in fishes from the Skagerrak

Marine fishes caught in the Skagerrak, 27 different species representing various groups of fishes (Cyclostomi, Holocephali, Elasmobranchii and Teleostei), were examined for the following haematological and biochemical blood parameters: haematocrit, haemoglobin, mean corpuscle haemoglobin concentration, total plasma protein, blood glucose and blood lactate. Interspecies variations as well as variations within some species were observed. The haemoglobin values for all species showed a positive correlation to the corresponding haematocrit values. Relatively low values for haematocrit and haemoglobin were found in cyclostomes, holocephaleans and elasmobranchii compared to the majority of teleosts. Within the teleost group, the haematocrit and haemoglobin levels were positively correlated with the activity of the fish species. The cyclostome Myxine glutimsa L. had a total plasma protein content in the same range as most teleosts, whereas holocephaleans, elasmobranchii and the deep-water teleost Coryphaenoides rupestris Gunnerus showed comparatively low values. Among teleosts some relationship seemed to exist between the total plasma protein level and the activity of the fish species. In addition, a correlation between plasma protein content and levels of blood lipids were noted. Values for blood glucose and blood lactate were found to be lower in cyclostomes, holocephaleans and elasmobranchii than in most teleosts. Higher blood glucose levels were observed in the more active teleost species.     

A method for detecting distant evolutionary relationships between protein or nucleic acid sequences in the presence of deletions or insertions

Summary A method for detecting homology between two protein or nucleic acid sequences which require insertions or deletions for optimum alignment has been devised for use with a computer. Sequences are assessed for possible relationship by Monte Carlo methods involving comparisons between the alignment of the real sequences and alignments of randomly scrambled sequences of the Same composition as the real sequences, each alignment having the optimum number of gaps. As each gap is successively introduced into a comparison (real or random) a maximum score is determined from the similarity of the aligned residues. From the distribution of the maximum alignment scores of randomly scrambled sequences having the same number of gaps, the percentage of random comparisons having higher scores is determined, and the smallest of these percentage levels for each pair of sequences (real or random) indicates the optimum alignment. The fraction of the comparisons of random sequences having percentage levels at their optimum alignment below that of the real sequence comparison at its optimum estimates the probability that such an alignment might have arisen by chance. Related sequences are detected since their optimum alignment score, by virtue of a contribution from ancestral homology in addition to optimised random considerations, occupies a more extreme position in the appropriate frequency distribution of scores than do the majority of optimum scores of randomly scrambled sequences in their appropriate distributions.Application of this optimum match method of sequence comparison shows that the sensitivity of the maximum match method of Needleman and Wunsch (1970) decreases quite dramatically with sequence comparisons which require only a few gaps for a reasonable alignment, or when sequences differ greatly in length. The maximum match method as applied by Barker and Dayhoff (1972) has the additional disadvantage that deletions which have occurred in the longer of two homologous protein sequences further decrease the sensitivity of detection of relationship. The constrained match method of Sankoff and Cedergren (1973) is seen to be misleading since large increments in the alignment score from added gaps do not necessarily result in a high total alignment score required to demonstrate sequence homology.     

Comparative biochemical analysis of the major yolk protein in the sea urchin egg and coelomic fluid

The major yolk protein (MYP) is localized to the egg and coelomic fluid of the adult sea urchin. While the egg‐localized MYP has been extensively studied, much less is known about the coelomic fluid‐localized protein. Therefore, we have conducted a comparative biochemical analysis of these proteins. Sucrose density gradient ultracentrifugation revealed unique elution profiles for the MYP species present in the egg, 170‐ and 240 kDa, and the coelomic fluid, 180‐ and 250 kDa. Fractionation in polyacrylamide gels revealed that under reducing conditions both species were present in each location. However, in the absence of reducing agent only one species was present in each fraction: 240 kDa in the egg and 250 kDa in the coelomic fluid. In addition, V8 peptide mapping indicated that all four species have very similar primary structures. Circular dichroic spectral analysis and endogenous tryptophan measurements of the purified 170‐ and 180 kDa species revealed distinctive secondary and tertiary structural features with notable differences in their responses to calcium: apparent Kds of 245‐ and 475 μmol/L were measured for the 170‐ and 180 kDa species, respectively. Further analysis revealed that both species have differing calcium requirements for binding to membranes as well as protein‐dependent, membrane‐membrane interaction. We discuss the functional implications arising from the structural differences which exist between the egg and coelomic fluid resident MYPs.