Analysis of morphogenetic mutants of hydra

Summary A mutant ofHydra attenuata is analysed, theaberrant, which is distinct from the wild type in having a smaller head with fewer tentacles and only half the number of head-specific cells. The rate of head and foot regeneration and the doubling time are slower inaberrants than in normal hydra.The lower head-forming potential is paralleled by a reduced concentration of head-specific morphogens: compared to the wild type, in theaberrant the concentration of head activator is reduced to 70% in the head and to 50% in the body, the concentration of head inhibitor is reduced to 50% in the head and to 80% in the body. Theaberrant is more sensitive (3 times) to added head activator and less sensitive (>5 times) to added head inhibitor than the wild type.The slower rate of foot regeneration is paralleled by a lower content of foot-specific morphogens: compared to the wild type, in theaberrant the foot activator is reduced to 40% and the foot inhibitor to 70%.     

Quantitative relationships of specific adsorption of colicins

The decrease in the number of sensitive bacteria in the presence of an excess of colicin is proportionate to their initial concentration; the proportion of surviving cells is not entirely constant, but is to some extent directly correlated to the initial cell concentration. The percentage of surviving cells is in inverse proportion to the colicin titre. The amount of nonadsorbed colicin is directly proportionate to the initial colicin titre. In the presence of an excessive number of sensitive bacteria in the suspension, the free colicin titre is much more lowered than in the suspension of resistant bacteria, the decrease being directly correlated to the number of bacteria in the suspension. Resistant—and even heterologous— bacteria can also adsorb large amounts of colicin nonspecifically, however. The experiments provide evidence in support of the concept of the lethal unit of colicin the course of adsorption of which is apparently different from that of phage.     

Mechanisms of nuclear translocation of insulin

Insulin (Ins) and various other hormones and growth factors have been shown to be rapidly internalized and translocated to the cell nucleus. This review summarizes the mechanisms that are involved in the translocation of Ins to the nucleus, and discusses its possible role in Ins action, based on observations by the authors and others. Ins is internalized to endosomes by both receptor-mediated and fluid-phase endocytosis, the latter occurring only at high Ins concentrations. The authors recently demonstrated the caveolae are the primary cell membrane locations responsible for initiating the signal transduction cascade induced by Ins. Once Ins is internalized, Ins dissociates from the Ins receptor in the endosome, and is translocated to the cytoplasm, where most Ins is degraded by Ins-degrading enzyme (IDE), although how the polypeptides cross the lipid bilayer is unknown. Some Ins escapes the degradation and binds to cytosolic Ins-binding proteins (CIBPs), in addition to IDE. IDE and some CIBPs are known to be binding proteins for other hormones or their receptors, and are involved in gene regulation, suggesting physiological relevance of CIBPs in the signaling of Ins and other hormones. Ins is eventually translocated through the nuclear pore to the nucleus, where Ins tightly associates with nuclear matrix. The role of Ins internalization and translocation to the nucleus is still controversial, although there is substantial evidence to support its role in cellular responses caused by Ins. Many studies indicate that nuclear translocation of various growth factors and hormones plays an important role in cell proliferation or DNA synthesis. It would be reasonable to suggest that tial for the regulation of nuclear events by Ins.     

Designation of Pathotypes of Plant Pathogens

For evaluation and communication of data on populations of plant pathogens a sensible code to name pathotypes can be extremely helpful. Starting from a coding system proposed by Habgood in 1970, a system, called “coded triplets” is developed which has the same advantages but is easier to understand and to use. This is especially useful as, in the meantime, pathotypes did become increasingly complex due to the increased number of genes conferring race specific resistance in the host. An important advantage of the coded triplets is that codes change only at one digit if, for example, a new differentia) is added or if the pathotype changes from avirulence to virulence or vice versa on a single differential. In this way evoluationary patterns and changes in the pathogen population can be visualized easily. The system is used to describe complex data on haplotypes of the barley mildew pathogen, but it is suited equally well for designation of pathotypes of other pathogens. Some basic principles of coded triplets are similar to octal notation, described by Gilmour in 1973, which has, however, not become widely known. Reasons for this are discussed. – There is a fourth system belonging to the same group of mathematical, condensing codes. As there is reason to believe that the evolution of condensing codes is drawing to an end, the systems are compared extensively, and the benefits of a generally accepted designation are outlined.     

Veterinary clinical application of GnRH--questions of efficacy

The efficacy of GnRH treatments are reviewed in relation to prevention of embryo mortality, control of follicle development in synchronization programmes using PG as luteolysin, induction of ovulation in post-partum anoestrus and in bovine cystic ovarian disease. It is suggested that in cattle that GnRH is effective in increasing pregnancy rates when given either at the time of insemination (first or repeat) or between days 11 and 14 after insemination. Evidence is also presented for positive effects on pregnancy rates in sheep, mares and sows. Use of GnRH as an integral part of synchronising regimens where it is given 7 days before PG and then again 48-60 h after PG appears to be effective in increasing the synchrony of ovulation in controlled breeding programmes. The main synchronizing effect seems to reside in the second GnRH injection whereas the importance of the first is in prolonging the luteal phase in those cows treated late in the cycle. The published work on the potential use of GnRH to induce ovulation in anovulatory cattle is reviewed. Neither bolus dose injections, pulsatile, continuous infusion, nor controlled release formulations of GnRH, have yet proved effective in inducing fertile ovulations in a predictable or consistent manner. It is suggested that this is due to the variability of follicular status when treatment is initiated. GnRH is commonly used in the treatment of bovine cystic ovarian disease. However, although stimulating ovulation/luteinisation of a new follicle and luteinisation of the cyst, fertility of treated cattle remains very poor and it is suggested that a better understanding of the disease is needed before more effective treatments can be developed.     

The fate of the blastocele and homology of early stages of vertebrate embryos

A disputable problem is discussed, which cavity in the Amniota embryo corresponds to blastocoele. General morphophysiological characteristics of the embryos at the blastula stage are presented. Basing on comparative survey of the data on origin, functions and fate of the blastocoele in development of vertebrate embryos, the notion is substantiated that the subembryonal cavity corresponds to blastocoele in Amniota. A critical analysis is given to another interpretation, according to which blastocoele in Amniota is a cleft between epi- and hypoblast. Ideas on homology criteria are explained, with a reference to initial stages of the embryonal development. Since prospective importance of blastocoele in low Chordata (convertion into gastrocoele) is different, a conclusion is made about incomplete homology of blastocoele in the animals mentioned. A hypothesis is put forward on pathways of changes of prospective importance of blastocoele in the vertebrate phylogenesis, in connection with their transition to meroblastic development. The problem on changes in assimilation of yolk by the vertebrate embryo at transition from holoblastic to meroblastic development is discussed from comparative point of view, as well as on nature of yolk entoderm in Amniota and Anamnia.     

液体培养基条件下乌毛蕨配子体发育的研究

在液体培养基条件下对中国产乌毛蕨(Blechnum orientaleL.)配子体发育进行了观察。结果表明:乌毛蕨的孢子为两面体型,两侧对称,极面观为椭圆形,赤道面观为半圆形或豆形,周壁具脊状褶皱;孢子萌发为书带蕨型;原叶体发育为三叉蕨型,成熟原叶体为对称的心脏形。经比较分析,蕨类植物孢子繁殖时采用混合土培养较适宜;液体培养基和混合土在研究蕨类植物配子体发育时同样具有可行性。孢子形态和配子体发育的观察结果表明,乌毛蕨是蕨类植物中较进化的种类;乌毛蕨科与鳞毛蕨科亲缘关系较近。     

Backward simulation of ancestors of sampled individuals

If the population is large and the sampling mechanism is random, the coalescent is commonly used to model the haplotypes in the sample. Ordered genotypes can then be formed by random matching of the derived haplotypes. However, this approach is not realistic when (1) there is departure from random mating (e.g., dominant individuals in breeding populations or monogamy in humans), or (2) the population is small and/or the individuals in the sample are ascertained by applying some particular non-random sampling scheme, as is usually the case when considering the statistical modeling and analysis of pedigree data. For such situations, we present here a data generation method where an ancestral graph with non-overlapping generations is first generated backwards in time, using ideas from coalescent theory. Alleles are randomly assigned to the founders, and subsequently the gene flow over the entire genome is simulated forwards in time by dropping alleles down the graph according to recombination model without interference. The parameters controlling the mating behavior of generated individuals in the graph (degree of monogamy) can be tuned in order to match a particular demographic situation, without restriction to simple random mating.The performance of the approach is illustrated with a simulation example. The software (written in C-language) is freely available for research purposes at http://www.rni.helsinki.fi/∼dag/.     

An Analysis of the Response of Young Barley Seedlings to Time of Application of Nitrogen

The reasons for the sensitivity of young barley seedlings totime of application of nitrogen have been examined. It is shownthat the transfer of nitrogenous reserves from endosperm toembryo which begins at about 36 h from planting proceeds ata faster relative rate than that of dry matter as a whole. Inconsequence embryo and endosperm nitrogen contents become temporarilysimilar some 24–36 h earlier than is the case for dryweights. Addition of nitrate on day 2 does not affect ratesof transfer of endosperm reserves but leads to a significantlyhigher nitrogen content in the embryo of treated plants, particularlyin the shoots. This additional nitrogen is present as nitrateup to around day 5 when reduction of accumulated nitrate commencesin the first leaf in significant amounts. For plants up to 14 days old delay in application of nitrateleads to a lowering of total nitrogen level which is proportionalto the delay in treatment. This is so for all parts of the plantexcept the first leaf for which the evidence indicates thatlevels of total and organic nitrogen and of accumulated nitrateare much lower when treatment is made late. It is argued thatnitrate accumulation by the leaf becomes progressively lessas it reaches full expansion, but irrespective of time of nitrateapplication about 95 per cent of the additional nitrogen presentin the leaf is in organic form Significant increases in organic nitrogen are found from day6 for plants supplied with nitrate up to day 4; for plants suppliedon day 6, or day 8nitrateand nitrate reductase activity in leafextracts are found within 6 h of treatment. Peak levels of nitratereductase activity are found for all treatments around days8–10 when the first leaf is fully expanded and when photosyntheticactivity is maximal. However, late supply of nitrate leads toa lower level of enzyme activity. Nitrate reduction in the rootsystem is undetectably low, and it is concluded that a substantialamount of carbon translocated from leaf to roots is in the formof nitrogenous compounds. The effects of time of application are also found when ammoniumnitrogen is substituted for nitrate indicating that the responseis independent of effects on the nitrate reducing system inthe leaf. Some inhibition of growth, particularly of the roots,is found due to ammonium toxicity. Why plants supplied early with nitrate show superior growthand enhanced photosynthetic activity in the first leaves isexplained in terms of treatment alleviating the restrictiveeffects of declining endosperm reserves. This is only possibleif nitrogen is supplied while the first leaf is expanding andable to accumulateand utilise the available nitrogen. Late supplyis associated with failure to use the nitrogen provided leadingto a lower protein level in the leaf; this can be correlatedwith the smaller size of leaf and the lower rates of carbonfixation occurring there.     

Effect of the structure of phospholipid on the kinetics of intravesicle scooting of phospholipase A2

Action of pig pancreatic phospholipase A2 on vesicles of over 50 synthetic 1,2-diacylglycerol-3-phosphate derivatives and analogs is examined in the absence of any additives. In general, shorter acyl chains and small substituents on the phosphate make a better substrate, while phospholipids with large apolar substituents are not hydrolyzed. The interfacial turnover rate constant for scooting kinetics, ki, for the various phospholipids were from less than 0.1 to 1 per min. Intervesicle exchange of the bound enzyme is faster in vesicles of phospholipids with larger polar substituents, and it is promoted in the presence of anions like chloride, sulfate and thiocyanate. These factors lower the residence time of the enzyme on the bilayer and therefore effectively decrease the rate of hydrolysis. The apparent Km for the enzyme in the interface of anionic phospholipids in the presence of salts is in the 40 to 100 microM range which is 3- to 7-times larger than the dissociation constants for the bound enzyme measured by fluorescence enhancement of Trp-3. The quantum yield of the bound enzyme in vesicles of the various lipids is found to be up to 4-fold different. It is suggested that this difference is due to the E* + S to E*S equilibrium, where E*S has higher fluorescence intensity. The role of calcium in generating the enzyme binding site at the anionic interface, the role of anion anchoring site on the enzyme, and the relationship between the catalytic efficiency and the fluorescence quantum yields are discussed.     

Principles of covalent binding of reactive metabolites and examples of activation of bis-electrophiles by conjugation

Mechanisms of toxicity continue to be important in developing rational strategies to deal with chemicals present in the environment. Understanding and predicting toxicity have also become a critical step in the process of drug development. Covalent binding of chemicals to macromolecules is one aspect of toxicity, and the principles and outcomes of the process are considered. Two examples of chemicals for which several aspects of metabolism and reactions are understood are aflatoxin B(1) and polyhalogenated olefins. Ethylene dibromide is a compound that is activated to genotoxic half-mustards by conjugation with glutathione or the DNA repair protein O(6)-alkylguanine DNA alkyltransferase (AGT). The AGT reaction is unusual, in that crosslinking of the protein to DNA increases mutagenicity. One of the involved mechanisms is formation of N(7)-guanyl crosslinks and depurination to produce G-->T transversions; other reactions appear to yield the additional mutagenic events. The phenomenon of thiol conjugation to increase mutagenicity is widespread among bis-electrophiles.     

河南种子植物区系地理研究

河南省地处中原 ,属于我国南北过渡和东西过渡的重要区域 ,植物区系成分复杂多样并于周围地区联系广泛 ,对其植物区系研究对深入认识本省的自然环境特征及其在我国多种自然区划中的位置等有着重要意义。该文在最新资料的基础上 ,运用区系学原理对河南省种子植物区系的种类组成、地理成分 (属、种 2个层次上 )等进行了系统的分析 ,在此基础上概括出河南植物区系的基本特征为 :(1 )植物种类比较丰富 ,多样性较高 ;(2 )起源古老 ;(3 )地理成分复杂 ,温带成分略占优势 ,过渡性突出 ;(4 )中国特有植物比较丰富。     

Mechanisms of loss of latency of lysosomal enzymes. Effects of incubation on the properties of lysosomal membranes.

1. The effects of sucrose and KCl on the loss of latency of lysosomal enzymes caused by incubation at 37 degrees C, pH 7.4, were examined by using Triton-filled lysosomes from rat liver and two fractions from livers of rats not injected with Triton. 2. After incubation, the percentage free activity of lysosomal enzymes was measured before and after cooling to 0 degrees C in order to determine the amount of latency lost at 37 degrees C without cooling and the additional amount lost on cooling the incubated lysosomes to 0 degrees C. 3. The latency that is lost without cooling is first decreased and then increased by increasing the osmotic strength of the incubation medium with KCl, or with sucrose in the presence of KCl. However, if the osmotic strength is increased with sucrose alone, loss of latency is decreased up to 0.25M-sucrose, but is increased only slightly at higher sucrose concentrations. Apparently the lysosome is permeated by hyperosmolar KCl but not by sucrose during incubation. 4. If the osmotic strength of the assay medium is increased with KCl, the loss of latency caused by incubation for 60 min in hyperosmolar KCl is repressed. Thus it appears that a KCl-permeated lysosome can be obtained which is relatively stable until exposure to lower osmolarities. 5. The loss of latency caused by cooling incubated lysosomes to 0 degrees C is largely eliminated if the osmotic strength of the medium in which the lysosomes are cooled is raised sufficiently with either sucrose or KCl. 6. Osmotic-fragility curves were obtained after incubation for 1 and 60 min at iso-osmoticity (0.2M-KCl or 0.25 M-sucrose). Although little loss of latency occurs at iso-osmoticity, lysosomes incubated for 60 min display greatly increased fragility on exposure to hypo-osmolar KCl, hypo-osmolar sucrose or hyperosmolar KCl. 7. It is suggested that permeability to KCl at 37 degrees C and the increase in fragility on exposure to hypo-osmolar conditions are both consequences of injury, probably from enzymic action, sustained by the lysosomal membrane during incubation at 37 degrees C.     

马陆在森林生态系统物质转化中的功能研究

马陆是森林生态系统重要的分解者,在帽儿山林区,马陆摄食量随温度的升高而增加。据初步估算,马陆地对凋落物的分解量约占该地区年平均凋落物量的０．２１％。马陆对同一种、不同腐解程度的叶片摄食不同,对妆分解凋落物的摄食量大于对未分解凋落物的摄食量。在不同温度条件下,马陆的生态效率不同,其同化效率随温度升高而降低,而粪便率则随温度升高而增加。在不同林型下个体数量分布不均匀。通常、阔叶林＞针阔叶混交林＞针叶林。在土壤的垂直分布上,具有明显的表聚现象。马陆的个体数量季节变化明显,以夏末最多,冬末最少。     

The pathway of biosynthesis of abscisic acid in vascular plants: a review of the present state of knowledge of ABA biosynthesis.

The pathway of biosynthesis of abscisic acid (ABA) can be considered to comprise three stages: (i) early reactions in which small phosphorylated intermediates are assembled as precursors of (ii) intermediate reactions which begin with the formation of the uncyclized C40 carotenoid phytoene and end with the cleavage of 9'-cis-neoxanthin (iii) to form xanthoxal, the C15 skeleton of ABA. The final phase comprising C15 intermediates is not yet completely defined, but the evidence suggests that xanthoxal is first oxidized to xanthoxic acid by a molybdenum-containing aldehyde oxidase and this is defective in the aba3 mutant of Arabidopsis and present in a 1-fold acetone precipitate of bean leaf proteins. This oxidation precludes the involvement of AB-aldehyde as an intermediate. The oxidation of the 4'-hydroxyl group to the ketone and the isomerization of the 1',2'-epoxy group to the 1'-hydroxy-2'-ene may be brought about by one enzyme which is defective in the aba2 mutant and is present in the 3-fold acetone fraction of bean leaves. Isopentenyl diphosphate (IPP) is now known to be derived by the pyruvate-triose (Methyl Erythritol Phosphate, MEP) pathway in chloroplasts. (14C)IPP is incorporated into ABA by washed, intact chloroplasts of spinach leaves, but (14C)mevalonate is not, consequently, all three phases of biosynthesis of ABA occur within chloroplasts. The incorporation of labelled mevalonate into ABA by avocado fruit and orange peel is interpreted as uptake of IPP made in the cytoplasm, where it is the normal precursor of sterols, and incorporated into carotenoids after uptake by a carrier in the chloroplast envelope. An alternative bypass pathway becomes more important in aldehyde oxidase mutants, which may explain why so many wilty mutants have been found with this defect. The C-1 alcohol group is oxidized, possibly by a mono-oxygenase, to give the C-1 carboxyl of ABA. The 2-cis double bond of ABA is essential for its biological activity but it is not known how the relevant trans bond in neoxanthin is isomerized.     

The Influence of Temperature on the Effect of Bacteriostatic Concentrations of Phenol Against Escherichia coli

S ummary . During early exponential growth of Escherichia coli in the absence of phenol there is a natural death rate at 20, 30, and 44° but at the optimum temperature around 37° there is little if any significant death. The influence of a rise in temperature from 20 to 44° is to decrease the generation time and at 44° the lower generation time compensates for a reduced generation index. The main effect of sub-bacteriostatic concentrations of phenol is to increase the generation time but at 30, 37 and 44° there is a significant reduction in the generation index at the higher concentrations resulting in a dynamic bacteriostasis. At 20° bacteriostasis is due mainly to a large generation time but there is a little growth and so bacteriostasis is essentially dynamic. There is also evidence to suggest that the effect of a particular concentration of phenol on the generation index is not merely influenced by the temperature but by the generation time under the particular set of conditions. If phenol is added to rapidly growing cultures of E. coli the effect of a rise in temperature is to reduce the concentration required for bacteriostasis but if it is added during the lag phase there is a maximum in the bacteriostatic concentration between 20 and 37°.     

The rate of strand separation in alkali of DNA of irradiated Mammalian cells

When mammalian cells are treated with alkali of pH at about 12, the cells are lysed and the released DNA starts to uncoil. This process of DNA strand separation is accelerated if the cells have been exposed to ionizing radiation, and the effect is clearly detectable in the dose range 10-100 rads. The rate of strand separation is also influenced by temperature and ionic strength of the alkaline solution. The kinetics of DNA strand separation in alkali is studied for three conditions in terms of ionic strength and temperature, chosen in such a way that the effect of irradiation may conveniently be studied in the dose range 10 rads to 20 krads. The accelerating effect of ionizing radiation on DNA strand separation is probably due to DNA strand breakage and the technique described is thus a sensitive method of studying such damage to DNA. A model for the strand-separation process, based on the assumption that strand breakage causes the accelerating effect, is proposed and found to describe the experimental data adequately.     

Prediction of the power of detection of marker-quantitative trait locus linkages using analysis of variance

Analysis of variance can be used to detect the linkage of segregating quantitative trait loci (QTLs) to molecular markers in outbred populations. Using independent full-sib families and assuming linkage equilibrium, equations to predict the power of detection of a QTL are described. These equations are based on an hierarchical analysis of variance assuming either a completely random model or a mixed model, in which the QTL effect is fixed. A simple prediction of power from the mean squares is used that assumes a random model so that in the mixed-model situation this is an approximation. Simulation is used to illustrate the failure of the random model to predict mean squares and, hence, the power. The mixed model is shown to provide accurate prediction of the mean squares and, using the approximation, of power.     

Karyotype Analysis of 5 Species of Polygonatum Mill.

The present paper reports the chromosome numbers and karyotypes of five species in Polygonatum from Anhui of China. The materials used in this work are listed in Table 1, Photomicrographs of somatic metaphase and karyograms of the five species of Polygonatum in Plate 1, 2, 3, the idiograms in Fig. 1-11 and a comparison of the karyotype of them is provided in Table 2. The results are shown as follows: 1. Polygonatum odoratum (Mill.)Druce Two materials were examined. One from Mt. Huangshan, Anhui, has 2n= 16 = 10m (3sc)+ 6sm (Plate 1 :A, B). The idiogram is shown in Fig. 1. The chromosomes range in length from 2.85 to 8.85 μm, with the total length 48.63μm and the ratio of the longest to the shortest 3.11, The karyotype belong to Stebbins’(1971) 2B. The two chromosomes of the first pair have arm ratios 1.01 and 1.29 respectively, and The first pair has one chromosome carrying a satellite attached to the short arm, showing heterozyosity .The chromosome num ber of 2n= 16 in P. odoratum and its karyotype are reported for the first time. The other from Langyashan, Chu - xian, Anhui, is found to have 2n = 18 = 10m (Isc)+2sm+6st(2sc) (Plate 1: C, D). The idiogram is shown in Fig. 2. The chromosomes range in length from 2.43 to 8.29μm, with the total length 46.67µm and the ratio of the longest to the shortest 3.41. The karyotype is also of 2B. In a somatic chromosome complement the 2nd pair have one chromosome carrying a satellite attached to the long arm, showing heterozygosity. 2. Polygonatum filipes Merr. Two materials were examined. One from the Huangshan, Anhui is found to have two cytotypes: 2n= 16 and 2n=22. This paper reports one of them. The karyotype formula is 2n=22=8m+8sm(2sc)+6st(Plate 3: Q, R). The idiogram is shown in Fig. 3. The chromosomes range in length from 2.55- 5.85μm, with the total length 45.01 μm and the ratio of the longest to the shortest 2.29. The karyotype belongs to 3B. The other material from the Fangchang, Anhui, is shown to have four cytitypes: 2n= 14, 2n= 16, 2n=20 (Plate 3: W) and 2n=22. This paper reports two of them. Type I: the karytype formula is 2n=14=10m+4sm (Plate 3: S, T). The idiogram is shown in Fig. 5. The chromosomes range in length from 2.59 to 7.61μm, the total length 37.44μm and the ratio of the longest to the shortest is 2.94. the karyotype belongs to 2B. Type II :The karyotype formula is 2n=16=8m+4sm+4st (Plate 3: U, V). The idiogram is shown in Fig. 4. The chromosomes range in length from 2.65 to 8.21 μm, the total length 46.01 μm and the ratio of the longest to the shortest 3.10. The karyotype belongs to 2B. The chromosome numbers of 2n=20, 2n= 14 and 2n=22, and karyotype of 2n= 14 and 2n=22 in P. filipes are reported for the first time. 3. Polygonatum cytonema Hua Two materials were examined. One from the Langyashan, Chuxian, anhui, is found to have 2n = 18 = 8m (2sc)+ 6sm+ 4st (Plate 2: K, L). The idiogram is shown in Fig. 7. The chromosomes range in length from 3.41 to 9.21 μm, the total length 56.34μm and the ratio of the longest to the shortest is 2.70. The karyotype belongs to 2B. The other material from the Huangshan, Anhui, has two cytotypes: 2n=20 and 2n= 22. Type I: The karyotype formula is 2n= 20= 8m+ 6sm+ 6st (Plate 2: M, N). The idiogram is shown in Fig. 8. The chromosomes range in length from 1.75 to 5.03μm, with the total length 32. 91μm and the ratio of the longest to the shortest 2. 87. The karyotype is also of 2B. Type II: The karyotype formula is 2n=22=6m+ 8sm+4st+ 4t (Plate 2: O, P ). The idiogram is Shown in Fig. 10. The chromosomes range in length from 1.75 to 4.95 μm, with total length 35.05μm and the ratio of the longest to the shortest 2.83. The karyotype brlongs to 3B. 4. Polygonatum desoulayi kom. The material from Xuancheng, Anhui, is found to have karyotype 2n = 22 = 10m (2sc) + 6sm (lsc) + 6st ( Plate 2. I, J). The idiogram is shown in Fig. 6. The chromosomes range in length from 1.86 to 5.61μm, with the total length 41.98μm and the ratio of the longest to the shortest 3.02. The karyotype is also of 3B. The first pair has one chromosome carrying a satellite attached to the long arm, showing heterozygosity. The chromosome number and karyotype of Chinese material are reported for the first time. 5. Polygonatum verticillatum (L.) All. The material from the Langyashan, Chuxian, Anhui is found to have two cytotypes. Type 1: the karyotype formula is 2n = 18 = 2m+ 2sm+ 10st+ 2t+ 2T (Plate 1: G, H). The idiogram is shown in Fig.9. The chromosomes range in length from 1.86 to 4.03μm, with total length 28.28μm and the ratio of the longest to the shortest 2.17. The karyotype classification belongs to 3B. Type II: The karyotype formula is 2n=24=6m+4sm+12st+2T (Plate 1: E, F). The idiogram is shown in Fig. II. The chromosomes range in length from 2.01 to 5.03μm, with total length 41.36μm and the ratio of longest to shortest 2.50. The karyotype is also of 3B. The chromosome numbers and karyotypes of Chinese material are reported for the first time.     

Measurement of the kinetics of inhibition of activated coagulation factor X in human plasma: the effect of plasma and inhibitor concentration

A method has been developed for detailed kinetic studies of the inhibition of factor Xa in human plasma. Radiolabeled enzyme is not required, and the method can be used at initial factor Xa levels of 1 nM. The method is discontinuous and based on the removal of samples into an amidolytic assay done in the presence of 1% Lubrol-PX detergent. This permits the study of inhibition in mixtures containing phospholipid, platelets, or thromboplastin. The method can be used at inhibition rates in excess of 1 min-1, and by suitable analysis can be used to estimate the contribution of inhibition by alpha 2-macroglobulin, which does not itself inhibit amidolytic activity. The method is at present limited to cases where thrombin is not generated in large excess. Factor Xa inhibition has been studied in citrated plasma as a function of total plasma concentration, and--by the use of antithrombin-depleted plasma--as a function of the antithrombin concentration of the plasma. In all situations inhibition is characterized by second-order behavior: (i) total inhibition rate is proportional to plasma concentration up to 95%, giving a maximum rate in the absence of calcium of 1 min-1; (ii) inhibition in depleted plasma reconstituted with antithrombin shows inhibition rate to remain linearly related to antithrombin concentration; and (iii) the estimated rate due to alpha 2-macroglobulin is proportional to plasma concentration. It is thus confirmed that, as in pure systems, inhibition of factor Xa in whole plasma is linearly related to the concentration of each class of inhibitor.