大壁虎的染色体及减数分裂联会复合体的研究

大壁虎(Gekko gecko)的染色体数目为2n=38,核型由2对中着丝粒(Nos.1.4.)、3对亚中着丝粒(Nos.2.3.5)及14对端着丝粒和亚端着丝粒(Nos.6—19)染色体组成。一对核仁组织者(NOR_s),位于第7对端着丝粒染色体的末端。同时,本文还对大壁虎的减数分裂以及联会复合体(S.C)的结构和组型,进行了详细的观察和分析。     

Subfamily of submaxillary gland-specific Mup genes: chromosomal linkage and sequence comparison with liver-specific Mup genes

Mouse major urinary proteins (MUPs) are encoded by a family of ca. 35 genes that are expressed in a tissue-specific manner in several secretory organs; in the liver, in the submaxillary, sublingual, parotid and lachrymal glands, and in the skin sebaceous glands. In this paper we describe the isolation of a Mup gene, Mup-1.5a, which is expressed predominantly in the submaxillary gland of BALB/c mice. We show that Mup-1.5a is a member of a subfamily consisting of two closely related genes, both of which are closely linked to the Mup-1 locus on mouse chromosome 4. Mup-1 is the locus of a class of Mup genes (Group 1) expressed in the liver. The complete nucleotide sequence of Mup-1.5a has been determined, and was compared to a previously sequenced Group 1 Mup gene. The comparison shows that the differentially expressed Mup genes are uniformly divergent in exons, introns and in their flanking sequences. The regions of homology extend at least 5 kb into the 5' flanking region of Mup genes.     

Adaptive on-line optimizing control of bioreactor systems

Several on-line optimizing control strategies were proposed and tested by computer simulation for the efficient operation of bioreactors. The control task was divided into two, one of which was to search for the optimal operating point and passed the set point to the lower layer of which task was to make the process output follow the set point as soon as possible. It was shown to be effective for the upper layer to express the objective function as a polynomial with respect to the measurement variable and to make use of it for finding the optimum point. Noting that the major dynamic characteristics of bioreactor system is the time-varying and nonlinear nature, the adaptive type control system is in evitable. It was shown to be quite effective to use discrete type self-tuning PID controller and the optimal controller compensated for the interaction between the control loops.Application was made to the cell recycle system for the production of lactic acid and baker's yeast cultivation. I was found from the former application that the control quality can be significantly improved by incorporating the decoupling strategy into the lower layer closed-loop system. It was also found from the latter application that the initial startup period can be significantly reduced by making use of the rough mathematical model.     

Higher order structure is present in the yeast nucleus: autoantibody probes demonstrate that the nucleolus lies opposite the spindle pole body

A panel of sera from 892 autoimmune patients was screened by indirect immunofluorescence on mammalian cells. Seventy-three sera were identified that recognize the nucleolus. Three of these sera appear to stain the nucleolus in yeast, suggesting that they recognize highly conserved antigens. These three sera also immunoprecipitate mammalian U3 snRNA-containing particles, which reside in the nucleolus and have been implicated in rRNA processing. Double immunofluorescence experiments with anti-nucleolus and anti-tubulin antibodies revealed a novel form of non-random nuclear organization in yeast. The spindle pole body and the nucleolus — both of which are associated with the nuclear envelope — preferentially localize at opposite ends of the nucleus. Organization of these and other components into specific regions of the nucleus may be important for optimizing their proper function.     

Nonparametric confidence interval estimators for heritability and expected selection response

Statistical methods have not been described for comparing estimates of family-mean heritability (H) or expected selection response (R), nor have consistently valid methods been described for estimating R intervals. Nonparametric methods, e.g., delete-one jackknifing, may be used to estimate variances, intervals, and hypothesis test statistics in estimation problems where parametric methods are unsuitable, nonrobust, or undefinable. Our objective was to evaluate normal-approximation jackknife interval estimators for H and R using Monte Carlo simulation. Simulations were done using normally distributed within-family effects and normally, uniformly, and exponentially distributed between-family effects. Realized coverage probabilities for jackknife interval (2) and parametric interval (5) for H were not significantly different from stated probabilities when between-family effects were normally distributed. Coverages for jackknife intervals (3) and (4) for R were not significantly different from stated coverages when between-family effects were normally distributed. Coverages for interval (3) for R were occasionally significantly less than stated when between-family effects were uniformly or exponentially distributed. Coverages for interval (2) for H were occasionally significantly less than stated when between-family effects were exponentially distributed. Thus, intervals (3) and (4) for R and (2) for H were robust. Means of analysis of variance estimates of R were often significantly less than parametric values when the number of families evaluated was 60 or less. Means of analysis of variance estimates of H were consistently significantly less than parametric values. Means of jackknife estimates of H calculated from log transformed point estimates and R calculated from untransformed or log transformed point estimates were not significantly different from parametric values. Thus, jackknife estimators of H and R were unbiased. Delete-one jackknifing is a robust, versatile, and effective statistical method when applied to estimation problems involving variance functions. Jackknifing is especially valuable in hypothesis test estimation problems where the objective is comparing estimates from different populations.     

Assay of L-3-hydroxyacyl-coenzyme A dehydrogenase with substrates of different chain lengths

A method for assaying L-3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) which permits rate measurements with L-3-hydroxyacyl-CoA substrates of various chain lengths at physiological pH is described. The method is based on a coupled assay system in which 3-ketoacyl-CoA compounds formed by the dehydrogenase are cleaved by 3-ketoacyl-CoA thiolase (EC 2.3.1.16) in the presence of CoASH. The advantages of this assay method are its irreversibility and elimination of product inhibition. The assay procedure was used to determine the kinetic parameters (Km, Vmax) of pig heart L-3-hydroxyacyl-CoA dehydrogenase with several substrates of various chain lengths. The data obtained show the enzyme to be most active with medium-chain substrates whereas Km values for medium-chain and long-chain substrates are almost equal but much lower than those previously reported.     

2-ketoacid dehydrogenase complexes of Escherichia coli: stereospecificities of the three components for (R)-lipoate

Stereospecificities of component enzymes in the pyruvate dehydrogenase complex and 2-ketoglutarate dehydrogenase complex from Escherichia coli for lipoate and dihydrolipoate are determined. Assays of the component enzymes using R,S-, R-, or S-lipoate or the enantiomers of dihydrolipoate show that only the R-enantiomers are substrates for these enzymes. Nonenzymatic reactions involving acetyl group transfer and coupled electron and acetyl group transfer between enantiomeric molecules of lipoate or/and dihydrolipoate proceed at significant rates. Coupled acetyl group and electron transfer from enzyme-bound acetyldihydrolipoyl moieties to free lipoate is also observed. The S-enantiomers are neither substrates nor inhibitors; however, products of S-enantiomers are slowly generated in enzymatic reactions owing to nonenzymatic reactions between enzyme-bound acetyldihydrolipoyl-groups and free S-lipoate or S-dihydrolipoate.     

The effect of crosslinking by bis(3,5-dibromosalicyl) fumarate on the autoxidation of hemoglobin

Bis(3,5-dibromosalicyl) fumarate was used to crosslink hemoglobin both in the oxy and deoxy states. This double headed diaspirin was known to crosslink oxy Hb A selectively between Lys 82 beta 1 and Lys 82 beta 2 (Walder, J. A., et al. (1979) Biochemistry 18, 4265) and deoxy Hb A between Lys 99 alpha 1 and Lys 99 alpha 2 (Chatterjee R. Y., et al. (1986) J. Biol. Chem. 261, 9929). The autoxidation at 37 degrees C of oxy alpha 99 crosslinked hemoglobin was found to be 1.8 times as fast as that of Hb A while that of the oxy beta 82 crosslinked hemoglobin was only 1.2 times as fast. After 5 hours the formation of methemoglobin in the alpha crosslinked Hb A is 21.3% compared to 10.8% in beta crosslinked Hb A and 6.4% in Hb A. These results may effect the proposed use of alpha 99 crosslinked hemoglobin as a blood substitute by demonstrating the need for protection from autoxidation during storage.     

Fetal and adult sheep adrenal cortical cells contain glucocorticoid receptors

Specific receptors for glucocorticoids were identified in the fetal and adult sheep adrenal cortex by a whole-cell binding assay using [3H]triamcinolone acetonide ([3H]TA) as the radiolabelled ligand. [3H]TA binding sites were saturable and of high affinity, with dissociation constant (Kd) of 2-3nM. Scatchard analysis revealed a single class of binding sites with a binding capacity (Bmax) of 207 and 5 fmol/10(6) cells for d100 fetuses and adults, respectively. By single point analyses at saturating [3H]TA concentration, we found that glucocorticoid receptors (GR) were present in the fetal adrenal cortex as early as d60. Highest concentrations were found at d100-110. GR decreased to d125, then increased to term (approx. d145) before declining again in newborn and adult animals. This demonstration of glucocorticoid receptors in ovine fetal adrenal cortical cells provides a mechanistic basis for the concept that glucocorticoids may act, perhaps in a paracrine or autocrine fashion, to influence adrenocorticotropin (ACTH)-induced activation of fetal adrenal function and the events leading to parturition.