Linkage disequilibrium in crosses between Illinois maize strains divergently selected for protein percentage

The objectives of this study were two fold: (1) to determine whether divergent selection for kernel protein concentration, which produced the Illinois high protein (IHP), Illinois low protein (ILP), reverse low protein (RLP), and reverse high protein (RHP) maize (Zea mays L.) strains, had generated coupling-phase linkages among genes controlling protein concentration or other traits and (2) to measure the effectiveness of random mating in reducing linkage disequilibrium in segregating generations from crosses between the strains. To achieve these objectives, design III progenies from the F₂ and F₆ (produced by random mating the F₂) from the crosses of IHP × ILP, IHP × RHP, ILP × RLP, and RHP × RLP were evaluated. Estimates of additive variance for percent protein in the crosses of IHP × ILP and ILP × RLP were significantly less in the F₆ than in the F₂ indicating the presence of coupling-phase linkages in the parents and their breakup by random mating. In addition, a significant reduction in dominance variance for grain yield from the F₂ to the F₆ in IHP × ILP suggested the presence of repulsion-phase linkages. No other evidence of coupling or repulsion-phase linkages was found for any of the traits measured. These results demonstrate the effectiveness of long-term divergent selection in the development of coupling-phase linkages and of random mating to dissipate linkage disequilibrium.Research supported by the Illinois Agricultural Experiment Station     

Studies on the striatal dopamine uptake system of weaver mutant mice and effects of ventral mesencephalic grafts

The dopamine (DA) uptake system was investigated in the mesostriatal system of normal and weaver mutant mice, which lose mesencephalic DA neurons, as well as in weaver mutants with ventral mesencephalic grafts to the striatum. Assays of [³H]DA uptake in striatal synaptosomal fractions in vitro and autoradiography of [³H]mazindol binding in brain sections were carried out in wild-type mice (+/+) and in the two hemispheres of homozygous weaver mutants (wv/wv) that had received unilateral grafts of mesencephalic cell suspensions to the right side. Net [³H]DA uptake, expressed as pmol/mg-protein/2-min, was on the average 50.6 in the striatum of wild-type mice, 7.9 in the non-grafted, and 10.1 in the transplanted striatum of weaver mutants. [³]DA uptake in wild-type mice differed significantly from both the grafted and non-grafted weaver striata (P<0.001). Paired comparisons for [³H]DA uptake between right and left sides of recipient weaver mice showed a significant side effect (P<0.02), the right side being 28–38% higher than the left side [mean of all individual (R-L)/L values]. The results of amphetamine-induced turning behavior tests were compared with the biochemical findings. Mice with grafts to the right side rotated an average of 22 turns to the left and 7 turns to the right during the five one-minute sessions; the mean value L/(L+R) was 64%. A plot of (L-R) rotations against (R-L) [³H]DA uptake gave a correlation coefficient of 0.552 (P<0.05), indicating that animals with a strong rotational bias to the left tended to have higher [³H]DA on the right. Similarly, the animals that were used for [³H]mazindol binding autoradiographic studies displayed on the average 72% rotations to the left side. In the [³H]mazindol binding data, non-grafted weaver mutants showed the severest depletion relative to wild-type in the dorsomedial and dorsolateral caudate-putamen (86% and 87%, respectively). Mice with unilateral grafts to the right side showed an increase in [³H]mazindol binding signal in the transplanted side of 40–64% (depending on dorsoventral topography) over the contralateral, non-grafted side. These findings attest to the functional effects of the grafts at the anatomical, biochemical, and behavioral levels. The parallel measurements of motor performance and DA uptake in the same animals offers an index of behavioral recovery as a function of transmitter-related activity. Furthermore, by conducting measurements of the synaptosomal DA uptake in vitro and of the binding characteristics of mazindol in brain slices by autoradiography, one has the advantage of combining the anatomical resolution of uptake site visualization with a dynamic indicator of function for DA uptake in the nerve terminal.Special issue dedicated to Professor Sidney Ochs     

Effect of morphine and abstinence syndrome on [3H]bromoxidine binding to α2-adrenoreceptors in rat brain

At 4 days after the implantation of two subcutaneous 75 mg morphine pellets in the back skin, rats were morphine-dependent. In the three layers studied in the occipital cortex we found that the values of the ₂-adrenergic agonist [³H]bromoxidine binding increased with respect to animals implanted with placebo pellets. Typical behavioral and physiological symptoms of the abstinence syndrome appeared 30 minutes after administration of naloxone, [³H]bromoxidine binding values being similar to those obtained in animals implanted with placebo pellets. The pattern of response of the [³H]bromoxidine binding was similar in the hippocampus and the superficial gray layer of the superior colliculus of the mesencephalon, but the differences were not statistically significant in these areas. This paper concludes that exist brain regional differences in the ₂-adrenoreceptors response under morphine-treatment and possibly under naloxone-induced morphine abstinence syndrome.     

Bayesian analysis of linkage between genetic markers and quantitative trait loci. I. Prior knowledge

Summary Prior information on gene effects at individual quantitative trait loci (QTL) and on recombination rates between marker loci and QTL is derived. The prior distribution of QTL gene effects is assumed to be exponential with major effects less likely than minor ones. The prior probability of linkage between a marker and another single locus is a function of the number and length of chromosomes, and of the map function relating recombination rate to genetic distance among loci. The prior probability of linkage between a marker locus and a quantitative trait depends additionally on the number of detectable QTL, which may be determined from total additive genetic variance and minimum detectable QTL effect. The use of this prior information should improve linkage tests and estimates of QTL effects.     

对氨基苯甲酸酯同系物形成细胞色素P_（450）代谢中间体络合物的定量结构与活性关系

细胞色素Ｐ４５０（Ｐ４５０,Ｅｃ１．１４．１４．１）是一种十分重要的催化氧化反应的酶。本文测定了１２个对氨基苯甲酸酯同系物与Ｐ４５０相互作用而形成Ｐ４５０代谢中间体络合物的活性,用半经验分子轨道法ＭＮＤＯ－ＰＭ３计算得到了这些同系物的分子轨道指数,并用逐步多元回归分析法导出了活性与分子轨道指数及正辛醇／水分配系数的对数值（ＬｏｇＰ）之间的定量结构与活性关系（ＱＳＡＲ）。结果表明：对氨基苯甲酸脂同系物形成Ｐ４５０代谢中间体络合物的活性与原子净电荷的绝对值之和（∑Ｑ）和ＬｏｇＰ均具有很好的抛物线型相务性,同时,ＬｏｇＰ与∑Ｑ之间也存在相当好的相关性。     

Cellular Quantification of Tyrosine Hydroxylase in the Rat Brain by Immunoautoradiography

Abstract: We developed a rapid and sensitive radioimmunohistochemical method for the quantification of tyrosine hydroxylase (TH) at both the anatomical and cellular level. Coronal tissue sections from fresh-frozen rat brains were incubated in the presence of a TH monoclonal antibody. The reaction was revealed with a ³⁵S-labeled secondary antibody. TH content was quantified in catecholaminergic brain areas by measuring optical density on autoradiographic films or silver grain density on autoradiographic emulsion-coated sections. Regional TH concentrations determined in the locus ceruleus (LC), substantia nigra pars compacta (SNC), and ventral tegmental area (VTA) were significantly increased by 45% after reserpine treatment in the LC but unchanged in the SNC and VTA. Microscopic examination of TH radioimmunolabeling showed a heavy accumulation of silver grains over catecholaminergic cell bodies. In the LC, grain density per cell was heterogeneous and higher in the ventral than in the dorsal part of the structure. After reserpine treatment, TH levels were significantly increased (57%) in the neurons of the LC but not in those of the SNC or VTA. The data support the validity of this radioimmunohistochemical method as a tool for quantifying TH protein at the cellular level and they confirm that TH protein content is differentially regulated in noradrenergic and dopaminergic neurons in response to reserpine.     

Quantitative trait loci influencing protein and starch concentration in the Illinois Long Term Selection maize strains

A study was initiated to determine the number, chromosomal location, and magnitude of effect of QTL (quantitative trait loci or locus depending on context) controlling protein and starch concentration in the maize (Zea mays L.) kernel. Restriction fragment length polymorphism (RFLP) analysis was performed on 100 F₃ families derived from a cross of two strains, Illinois High Protein (IHP), X Illinois Low Protein (ILP), which had been divergently selected for protein concentration for 76 generations as part of the Illinois Long Term Selection Experiment. These families were analyzed for kernel protein and starch in replicated field trials during 1990 and 1991. A series of 90 genomic and cDNA clones distributed throughout the maize genome were chosen for their ability to detect RFLP between IHP and ILP. These clones were hybridized with DNA extracted from the 100 F₃ families, revealing 100 polymorphic loci. Single factor analysis of variance revealed significant QTL associations of many loci with both protein and starch concentration (P < 0.05 level). Twenty-two loci distributed on 10 chromosome arms were significantly associated with protein concentration, 19 loci on 9 chromosome arms were significantly associated with starch concentration. Sixteen of these loci were significant for both protein and starch concentration. Clusters of 3 or more significant loci were detected on chromosome arms 3L, 5S, and 7L for protein concentration, suggesting the presence of QTL with large effects at these locations. A QTL with large additive effects on protein and starch concentration was detected on chromosome arm 3L. RFLP alleles at this QTL were found to be linked with RFLP alleles at the Shrunken-2 (Sh2) locus, a structural gene encoding the major subunit of the starch synthetic enzyme ADP-glucose pyrophosphorylase. A multiple linear regression model consisting of 6 significant RFLP loci on different chromosomes explained over 64 % of the total variation for kernel protein concentration. Similar results were detected for starch concentration. Thus, several chromosomal regions with large effects may be responsible for a significant portion of the changes in kernel protein and starch concentration in the Illinois Long Term Selection Experiment.     

Effects of background adaptation on α-MSH and β-endorphin in secretory granule types of melanotrope cells of Xenopus laevis

Placing the clawed toad Xenopus laevis on a black background stimulates the melanotrope cells in the pars intermedia of the pituitary gland to release proopiomelanocortin (POMC)-derived peptides, including -MSH and N-acetyl-endorphin. In this study three types of secretory granules, electron-dense(130 nm Ø), moderately electron-dense ( 160 nm Ø) and electronlucent ( 180 nm Ø), have been identified in these cells. Apparently, only dark granules are formed by the Golgi apparatus and lucent granules release their contents via exocytosis. Immuno-electron microscopy (immunogold double labelling) of glutaraldehyde-fixed and freeze-substituted material shows that desacetyl--MSH and N-acetyl--endorphin coexist in all three granule types. Quantification of immunostaining revealed that immunoreactivities to these peptides are lowest in the dark granules and highest in the light ones. It is proposed that intragranular processing of POMC to immunoreactive desacetyl--MSH and N-acetyl--endorphin involves an increase in granule size and a decrease in granule electron density. Black background-induced activation of the melanotrope cell is reflected by an increase in immunoreactivity of the secretory granules to each of the antisera. This suggests that cell activation stimulates the formation of peptides by intragranular processing of POMC and/or of intermediate POMC-processing products. In addition, cell activation evoked an increase in the percentage of the granule population that reacts with anti-N-acetyl--endorphin, probably by stimulating intragranular acetylation of -endorphin. Apparently, this acetylation is a regulated event that occurs in the cytoplasm, independently from the acetylation of desacetyl--MSH which takes place near the plasmalemma at the time of granule exocytosis.     

红毛五加多糖对腹腔巨噬细胞作用的定量细胞化学研究

中药红毛五加(Acanthopanax giraldii Harms)属五加科植物,本文通过细胞化学定性、定位、定量研究探讨红毛五加多糖(AGPS)对腹腔巨噬细胞的作用及机理。实验证明AGPS能使巨噬细胞数量明显增多,细胞体积增大,伪足增多,吞噬能力增强,细胞内醣类、酸性磷酸酶、三磷酸腺昔酶、酸性酯酶和琥珀酸脱氢酶活性显著增强。用显微分光光度计对上述单个细胞的化学成分进行定量测定。实验组和对照组结果有显著差异。提示红毛五加的扶正固本作用十分明显,本研究为AGPS的应用和作用机理提供了一定的实验依据。     

Meta-analysis of iron metabolism markers levels of Parkinson’s disease patients determined by fluid and MRI measurements

BackgroundParkinson’ s disease (PD) is a progressive neurodegenerative disease featured neuropathologically by the loss of dopaminergic neurons of the substantia nigra (SN). Iron overload in the SN is mainly relative to the pathology and pathogenesis of PD. Postmortem samples of PD has indicated the increased levels of brain iron. However, there is no consensus on iron content through iron-sensitive magnetic resonance imaging (MRI) techniques and the alteration of iron and iron related metabolism markers levels in blood and cerebrospinal fluids (CSF) are still unclear based on the current studies. In this study, we performed a meta-analysis to explore the iron concentration and iron metabolism markers levels through iron-sensitive MRI quantification and body fluid.MethodsA comprehensive literature search was performed in PubMed, EMBASE and Cochrane Library databases for relevant published studies that analyzed iron load in the SN of PD patients using quantitative susceptibility mapping (QSM) or susceptibility weighting imaging (SWI), and iron metabolism markers, iron, ferritin, transferrin, total iron-binding capacity（TIBC）in CSF sample or serum/plasma sample (from Jan 2010 to Sep 2022 to filter these inaccurate researches attributed to unadvanced equipment, inaccurate analytical methods). Standardized mean differences (SMD) or mean differences (MD) and 95% confidence intervals (CI) with random or fixed effect model was used to estimate the results.ResultsForty-two articles fulfilled the inclusion criteria including 19 for QSM, 6 for SWI, and 17 for serum/plasma/CSF sample including 2874 PD patients and 2821 healthy controls (HCs). Our meta-analysis results founded a notable difference for QSM values increase (19.67, 95% CI=18.69–20.64) and for SWI measurements (−1.99, 95% CI= −3.52 to −0.46) in the SN in PD patients. However, the serum/plasma/CSF iron levels and serum/plasma ferritin, transferrin, total iron-binding capacity (TIBC) did not differ significantly between PD patients and HCs.ConclusionsOur meta-analysis showed the consistent increase in the SN in PD patients using QSM and SWI techniques of iron-sensitive MRI measures while no significant differences were observed in other iron metabolism markers levels.