Modulation of myocardial alpha 1- but not beta-adrenoceptors after 90-day tail-suspension

We have previously demonstrated that prolonged simulated microgravity (tail-suspension) leads to cardiac alterations with increased resting heart rate, myocardial degradation changes and attenuated myocardial contractility. The present study investigated the potential role of adrenoceptor mechanisms underlying them. Changes of myocardial alpha 1-adrenoceptor (alpha 1-AR) and beta 1-adrenoceptor (beta-AR) in 90-day tail-suspended rats was investigated by the method of radioligand binding assay and application of Scatchard's method. The results showed significantly decreased quantity of specific binding of 125I-BE[2-beta-(4-hydroxy-3-[125I]indophenyl)-ethylaminomethyltetralone] to alpha 1-AR present in membrane derived from ventricular myocardium of the suspended animals, despite the affinity of the alpha 1-AR to 125I-Be was unchanged. But neither the quantity nor the affinity of beta-AR binding to 125I-Pindolol was significantly altered. In addition, the spontaneously beating rate of isolated right atria from tail-suspended animals showed little change in sensitivity and reactivity to the stimulations of graded phenylephrine (alpha-agonist, measured in the presence of beta-antagonist propranolol) and isoproterenol (beta-agonist), compared with the control rats. There were also no obvious differences of the effects of the isoproterenol on the contractility of isolated left ventricular papillary muscles between the two groups. Since myocardial alpha 1-AR mediated-effects include production of cardiac hypertrophy and enhancement of myocardial glucose uptake and glycolysis, the down-regulation of the alpha 1-AR may be a contributor to the cardiac cellular accumulation and the myocardial degradation changes as found in our tail-suspended rats. The data from this study also suggest that the myocardial beta-adrenoceptors are not affected by the prolonged tail-suspension.     

RFLP mapping of the sugary enhancer1 gene in maize

RFLP marker data from an F₂₃ population derived from a cross between a sugary1 (su1) and a sugary enhancer1 (su1, sel) inbred were used to construct a genetic linkage map of maize. This map includes 93 segregating marker loci distributed throughout the maize genome, providing a saturated linkage map that is suitable for linkage analysis with quantitative trait loci (QTL). This population, which has been immortalized in the form of sibbed F₂₃ families, was derived from each of the 214 F₂ plants and along with probe data are available to the scientific community. QTL analysis for kernel sucrose (the primary form of sugar) concentration at 20 days after pollination (DAP) uncovered the segregation of seven major QTL influencing sucrose concentration; a locus linked to umc36a described the greatest proportion of the variation (24.7%). Since maltose concentration has previously been reported to be associated with the se1 phenotype, an analysis of probe associations with maltose concentration at 40 DAP was also conducted. The highly significant association of umc36a with maltose and sucrose concentrations provided evidence that this probe is linked to se1. Phenotypic evaluation for the se1 genotype in each F₂₃ family enabled us to map the gene 12.1 cM distal to umc36a. In contrast to previous work where se1 was reported to be located on chromosome four, our data strongly suggest that the sugary enhancer1 locus maps on the the distal portion of the long arm of chromosome 2 in the maize genome.     

Effect of human leukemia inhibitory factor on in vitro development of IVF-derived bovine morulae and blastocysts

This study was conducted to investigate whether human leukemia inhibitory factor (hLIF) improves the subsequent development of IVF-derived bovine morulae and blastocysts. To obtain IVF-derived bovine morulae, ova were matured and fertilized in vitro and cultured in 0.5 ml of synthetic oviduct fluid (SOF) medium supplemented with 10% human serum (HS) for 5 d at 39 degrees C under a gas atmosphere of 5% CO(2), 5% O(2), 90% N(2). Morulae and early blastocysts at Day 5 of culture were cultured in 0.5 ml of SOF medium with or without 5000 U/ml recombinant hLIF for 2 or 3 d (2 groups). To investigate the effect of addition of hLIF on the subsequent development of morulae, SOF medium was supplemented with 8 mg/ml BSA instead of HS. To test whether hLIF affects the subsequent development of IVF-derived bovine blastocysts, only good blastocysts that developed from SOF medium with or without hLIF at Days 7 and 8 of culture were frozen by a conventinal slow freezing method and again cultured in SOF medium with or without the addition of hLIF for 3 d after thawing (4 groups). Survival of frozen-thawed bovine embryos was evaluated for re-expansion and hatching of blastocysts during 3 d of culture. There was no significant difference in the developmental rate of Day 5 embryos to blastocysts between those cultured with (47.8%) and without (47.6%) addition of hLIF. However, the addition of hLIF before freezing significantly increased the hatching rate of IVF-derived bovine morulae (P < 0.05), whereas addition of hLIF after thawing did not increase the subsequent development of blastocysts. These results suggest that hLIF added at the Day 5 morula stage may contribute to bovine embryonic development through the hatching process.     

Lipase-catalyzed synthesis of lysophosphatidic acid in a solvent free system

Summary The direct, lipase-catalyzed esterifications of glycerol-3-phosphate in an organic solvent system and in a solvent free system were carried out. In a solvent free system only, LPA synthesis could be achieved within the acceptable reaction time. Open reaction system was preferable to closed reaction system for LPA synthesis. Yield of LPA isolated by silica gel column chromatography was 32.3%.     

Laminin and Neuropeptide Y Are Increased by Synapsin Transfection in Cultured NG108-15 Neuroblastoma/Glioma Hybrid Cells

Abstract: We have investigated the presence and expression of laminin and neuropeptide Y (NPY) in several NG108-15 cell lines transfected with synapsin Ib, IIa, or IIb. The content of laminin, a basal membrane glycoprotein that promotes adhesion and induces neurite outgrowth and neuronal differentiation, was increased in all transfected cell lines examined. In cells that were chemically differentiated with prostaglandin E₁ plus 3-isobutyl-1-methylxanthine, laminin levels were increased even further. The content of NPY, suggested to be a neurotransmitter/neuromodulator in peripheral sympathetic neurons as well as in central neurons, was also increased in all transfected cell lines examined. Immunohistochemical analysis combined with confocal laser microscopy showed that NPY staining was granular and very often enriched in neuritic varicosities. The distribution and the staining pattern of NPY were consistent with storage of NPY in large dense-cored vesicles. The results indicate that, in differentiated neurons, the synapsins increase the levels of a neuropeptide transmitter stored in large dense-cored vesicles and of an extracellular matrix protein associated with neuronal maturation.     

A human protein selected for interference with Ras function interacts directly with Ras and competes with Raf1.

The overexpression of some human proteins can cause interference with the Ras signal transduction pathway in the yeast Saccharomyces cerevisiae. The functional block is located at the level of the effector itself, since these proteins do not suppress activating mutations further downstream in the same pathway. We now demonstrate, with in vivo and in vitro experiments, that the protein encoded by one human cDNA (clone 99) can interact directly with yeast Ras2p and with human H-Ras protein, and we have named this gene rin1 (Ras interaction/interference). The interaction between Ras and Rin1 is enhanced when Ras is bound to GTP. Rin1 is not able to interact with either an effector mutant or a dominant negative mutant of H-Ras. Thus, Rin1 displays a human H-Ras interaction profile that is the same as that seen for Raf1 and yeast adenylyl cyclase, two known effectors of Ras. Moreover, Raf1 directly competes with Rin1 for binding to H-Ras in vitro. Unlike Raf1, however, the Rin1 protein resides primarily at the plasma membrane, where H-Ras is localized. These data are consistent with Rin1 functioning in mammalian cells as an effector or regulator of H-Ras.     

Deformation and flow of red blood cells in a synthetic lattice: evidence for an active cytoskeleton.

We introduce the use of microfabrication techniques to construct on a silicon wafer a synthetic capillary bed with 2.5- to 4-micron (mu)-wide channels. Establishment of a fluid pressure gradient allowed us to observe simultaneously using optical microscopy hundreds of cells flowing through the bed at physiological speeds. We find a large distribution of mobilities among red cells flowing through the structure; smaller channels provide a greater impedance to flow than larger ones, indicating that kinetic drag variations provide the origin of the distribution. The mobility of a particular cell is not correlated with the cell diameter but appears to be inversely correlated with intracellular calcium concentration of the cell, as determined by fluorescence of the calcium-binding dye fluo-3 AM. Also, we are able to use the parallel processing nature of our arrays to observe isolated events where the rigidity of the red cell seems to change suddenly over several orders of magnitude as it blocks a channel in the array.     

抗白粉病小麦染色体组型的分子标记与生化标记分析

应用与小麦第六同源群有关的分子和生化标记,包括ＤＮＡ探针ｐＳｃ５·３Ｈ３和ｐＳＲ１６７以及同工酶Ｅｓｔ－５和ａ－Ａｍｙ－１,对来自六倍体小黑麦Ｂｅａｇｌｅ与普通小麦科冬５８杂交后代Ｆ１花粉植株的抗白粉病株系Ｍ２４．Ｍ０９及Ｍ１７进行了分析。结果表明,Ｍ２４、Ｍ０９及Ｍ１７不同程度地含有黑麦染色体成分,而且电泳谱带差别较大,据此推断,Ｍ０９为６ＲＬ的易位系。因此,生化和分子标记不仅可以用于确定外源片段的存在,而且可以帮助确定染色体组型和外源片段的位置     

Identification of new mutations in the Cu/Zn superoxide dismutase gene of patients with familial amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder affecting motor neurons. Although most cases of ALS are sporadic, approximately 10% are inherited as an autosomal dominant trait. Mutations in the Cu/Zn superoxide dismutase gene (SOD 1) are responsible for a fraction of familial ALS (FALS). Screening our FALS kindreds by SSCP, we have identified mutations in 15 families, of which 9 have not been previously reported. Two of the new mutations alter amino acids that have never been implicated in FALS. One of them affects a highly conserved amino acid involved in dimer contact, and the other one affects the active-site loop of the enzyme. These two mutations reduce significantly SOD 1 enzyme activity in lymphoblasts. Our results suggest that SOD 1 mutations are responsible for > or = 13% of FALS cases.     

Construction and use of a nontoxigenic strain of Pseudomonas aeruginosa for the production of recombinant exotoxin A.

To express recombinant forms of Pseudomonas aeruginosa exotoxin A in high yield, we have developed a nontoxigenic strain of P. aeruginosa derived from the hypertoxigenic strain PA103. The nontoxigenic strain, designated PA103A, was produced by the excision marker rescue technique to replace the toxA structural gene in PA103 with an insertionally inactivated toxA gene. The PA103A strain (ToxA-) was used subsequently as the host strain for the expression and production of several recombinant versions of exotoxin A, and the results were compared with exotoxin A production in other P. aeruginosa and Escherichia coli strains. Use of the PA103A strain transformed with the high-copy-number pRO1614 plasmid bearing various toxA alleles resulted in final purification yields of exotoxin A averaging 23 mg/liter of culture. By comparison, exotoxin A production in other expression systems and host strains yields approximately 1/4 to 1/10 as much toxin.