Neonatal hepatitis induced by alpha 1-antitrypsin: a transgenic mouse model

Transgenic mouse lineages were established that carry the normal (M) or mutant (Z) alleles of the human alpha 1-antitrypsin (alpha 1-Pi) gene. All of the alpha 1-Pi transgenic mice expressed the human protein in the liver, cartilage, gut, kidneys, lymphoid macrophages, and thymus. The human M-allele protein was secreted normally into the serum. However, the human Z-allele protein accumulated in several cell types, but particularly in hepatocytes, and was found in serum in tenfold lower concentrations than the M-allele protein. Mice in one lineage carrying the mutant Z allele expressed high levels of human alpha 1-Pi RNA and displayed significant runting (50% of normal weight) in the neonatal period. This lineage was found to have alpha 1-Pi-induced liver pathology in the neonatal period, concomitant with the accumulation of human Z protein in diastase-resistant cytoplasmic globules that could be revealed in the Periodic acid-Schiff reaction (PAS). The phenotype of mice in the strain expressing high levels of the Z allele is remarkably similar to human neonatal hepatitis, and this strain may prove to be a useful animal model for studying this disease.     

Serum elastase inhibitor deficiency and alpha 1-antitrypsin deficiency in patients with obstructive emphysema

A decreased inhibition of pancreatic elastase has been detected in the serums of six patients with alpha(1)-antitrypsin deficiency. Five have severe clinical and physiological pulmonary emphysema. This observation extends the defect of inhibition by serum to a second, biologically active proteolytic enzyme in this form of familial emphysema.     

Clonal gene therapy: transplanted mouse fibroblast clones express human alpha 1-antitrypsin gene in vivo

A retroviral vector was used to insert human alpha 1-antitrypsin (alpha 1AT) complementary DNA into the genome of mouse fibroblasts to create a clonal population of mouse fibroblasts secreting human alpha 1AT. After demonstrating that this clone of fibroblasts produced alpha 1AT after more than 100 population doublings in the absence of selection pressure, the clone was transplanted into the peritoneal cavities of nude mice. When the animals were evaluated 4 weeks later, human alpha 1AT was detected in both sera and the epithelial surface of the lungs. The transplanted clone of fibroblasts could be recovered from the peritoneal cavities of those mice and demonstrated to still be producing human alpha 1AT. Thus, even after removal of selective pressure, a single clone of retroviral vector-infected cells that expressed an exogenous gene in vitro, continued to do so in vivo, and when recovered, continued to produce the product of the exogenous gene.     

Regulation of alloreactivity in vivo by a soluble form of the interleukin-1 receptor

In vitro studies have shown that cytokines are involved in the regulation of the immune response, but their role in vivo is less well defined. Specific cytokine antagonists enable the identification of particular cytokines involved in the response and offer a means for modifying it. Systemic administration of a soluble, extracellular portion of the receptor for interleukin-1 (sIL-1R) had profound inhibitory effects on the development of in vivo alloreactivity. Survival of heterotopic heart allografts was prolonged from 12 days in controls to 17 days in mice treated with sIL-1R. Lymph node hyperplasia in response to a localized injection of allogeneic cells was completely blocked by sIL-1R treatment. The inhibition was overcome by simultaneous administration of interleukin-1 (IL-1); thus, sIL-1R acts by neutralizing IL-1. These results implicate IL-1 as a regulator of allograft rejection and demonstrate the in vivo biological efficacy of a soluble cytokine receptor.     

Oxidative addition of ammonia to form a stable monomeric amido hydride complex

The insertion of an iridium complex into an N-H bond in ammonia leads to a stable monomeric amido hydride complex in solution at room temperature. This reaction advances the transition-metal coordination chemistry of ammonia beyond its role for more than a century as an ancillary ligand. The precursor for this insertion reaction is an iridium(I) olefin complex with an aliphatic ligand containing one carbon and two phosphorus donor atoms. Kinetic and isotopic labeling studies indicate that olefin dissociates to give a 14-electron iridium(I) fragment, which then reacts with ammonia. This cleavage of the N-H bond under neutral conditions provides a foundation on which to develop future mild catalytic transformations of ammonia, such as olefin hydroamination and arene oxidative amination.     

小麦-中间偃麦草异附加系Z4的外源染色质的分子标记

以中间偃麦草基因组DNA为探针对小麦中间偃麦草异附加系Z4进行基因组原位杂交分析，表明异附加系Z4附加的一对中间偃麦草染色体与普通小麦的一对染色体发生了相互易位。对中间偃麦草、Z4和普通小麦品种宛7107进行RAPD分析，在100条随机引物中，有两个引物S1053和S1068在Z4中能扩出中间偃麦草的特异带。在利用Z4进行小麦抗锈病育种时，可使用这两个标记进行辅助选择。     

Genetic defect in biosynthesis of the precursor form of the fourth component of complement

Under cell-free conditions, liver polysomes from guinea pigs genetically deficient in the fourth component of complement (C4) did not synthesize pro-C4 (the precursor of C4), but did synthesize nascent C4 polypeptides which remained polysome bound. The defect was specific for pro-C4 synthesis since the amounts of total protein and albumin synthesis and release from C4-deficient polysomes were similar to that in normal guinea pig liver polysomes.     

第一次及第二次抱卵的中华绒螯蟹胚胎和Z1幼体质量的比较

以中华绒螯蟹(Eriocheir sinensis)胚胎的湿重、胚胎直径、含水率、总脂和Z1幼体的体长、累计死亡指数(CMI)、50%死亡时间(PNR50)为评价指标,比较了第一次及第二次抱卵的胚胎和Z1幼体的性能。结果表明,两次抱卵的胚胎直径,湿重、干重具有显著性差异(P<0.05)。两次抱卵的胚胎含水率接近。在发育初期胚胎总脂的含量差异不大(P>0.05),在孵化前第二次抱卵胚胎的总脂含量低于第一次抱卵胚胎(P<0.05)。两次初孵Z1幼体的体长、总脂、CMI、PNR50差异显著(P<0.05)。综合各指标,第二次抱卵孵化所得的Z1幼体的质量不如第一次抱卵。     

第一次及第二次抱卵的中华绒螯蟹胚胎和Z1幼体质量的比较

以中华绒螯蟹(Eriocheir sinensis)胚胎的湿重、胚胎直径、含水率、总脂和Z1幼体的体长、累计死亡指数(CMI)、50%死亡时间(PNR50)为评价指标,比较了第一次及第二次抱卵的胚胎和Z1幼体的性能。结果表明,两次抱卵的胚胎直径,湿重、干重具有显著性差异(P<0.05)。两次抱卵的胚胎含水率接近。在发育初期胚胎总脂的含量差异不大(P>0.05),在孵化前第二次抱卵胚胎的总脂含量低于第一次抱卵胚胎(P<0.05)。两次初孵Z1幼体的体长、总脂、CMI、PNR50差异显著(P<0.05)。综合各指标,第二次抱卵孵化所得的Z1幼体的质量不如第一次抱卵。     

Blocking of HIV-1 infectivity by a soluble, secreted form of the CD4 antigen

The initial event in the infection of human T lymphocytes, macrophages, and other cells by human immunodeficiency virus (HIV-1) is the attachment of the HIV-1 envelope glycoprotein gp120 to its cellular receptor, CD4. As a step toward designing antagonists of this binding event, soluble, secreted forms of CD4 were produced by transfection of mammalian cells with vectors encoding versions of CD4 lacking its transmembrane and cytoplasmic domains. The soluble CD4 so produced binds gp120 with an affinity and specificity comparable to intact CD4 and is capable of neutralizing the infectivity of HIV-1. These studies reveal that the high-affinity CD4-gp120 interaction does not require other cell or viral components and may establish a novel basis for therapeutic intervention in the acquired immune deficiency syndrome (AIDS).     

Androgenesis conditioned by a mutation in maize

A maize embryo having the nuclear constitution of a reduced gametophyte cell is produced in 3 percent of the embryo sacs of inbred strain Wisconsin-23 that carry the mutant indeterminate gametophyte (ig). The nucleus of most monoploid sporophytes so derived is paternal. Such androgenetic monoploids may originate from a sperm nucleus acting in conjunction with the cytoplasm of a maternal cell from which the nucleus has been functionally displaced.     

Acquisition by innervated cardiac myocytes of a pertussis toxin-specific regulatory protein linked to the alpha 1-receptor

During development, the chronotropic response of rat ventricular myocardium to alpha 1-adrenergic stimulation changes from positive to negative. The alpha 1-agonist phenylephrine increases the rate of contraction of neonatal rat myocytes cultured alone but decreases the rate of contraction when the myocytes are cultured with functional sympathetic neurons. The developmental induction of the inhibitory myocardial response to alpha 1-adrenergic stimulation in intact ventricle and in cultured myocytes was shown to coincide with the functional acquisition of a substrate for pertussis toxin. A 41-kilodalton protein from myocytes cultured with sympathetic neurons and from adult rat myocardium showed, respectively, 2.2- and 16-fold increases in pertussis toxin-associated ADP-ribosylation (ADP, adenosine diphosphate) as compared to controls. In nerve-muscle cultures, inhibition of the actions of this protein by pertussis toxin-specific ADP-ribosylation reversed the mature inhibitory alpha 1-adrenergic response to an immature stimulatory pattern. The results suggest that innervation is associated with the appearance of a functional pertussis toxin substrate by which the alpha 1-adrenergic response becomes linked to a decrease in automaticity.     

Sequence and expression of mRNAs encoding the alpha 1 and alpha 2 subunits of a DHP-sensitive calcium channel

Complementary DNAs were isolated and used to deduce the primary structures of the alpha 1 and alpha 2 subunits of the dihydropyridine-sensitive, voltage-dependent calcium channel from rabbit skeletal muscle. The alpha 1 subunit, which contains putative binding sites for calcium antagonists, is a hydrophobic protein with a sequence that is consistent with multiple transmembrane domains and shows structural and sequence homology with other voltage-dependent ion channels. In contrast, the alpha 2 subunit is a hydrophilic protein without homology to other known protein sequences. Nucleic acid hybridization studies suggest that the alpha 1 and alpha 2 subunit mRNAs are expressed differentially in a tissue-specific manner and that there is a family of genes encoding additional calcium channel subtypes.     

Proapoptotic BAX and BAK modulate the unfolded protein response by a direct interaction with IRE1alpha

Accumulation of misfolded protein in the endoplasmic reticulum (ER) triggers an adaptive stress response-termed the unfolded protein response (UPR)-mediated by the ER transmembrane protein kinase and endoribonuclease inositol-requiring enzyme-1alpha (IRE1alpha). We investigated UPR signaling events in mice in the absence of the proapoptotic BCL-2 family members BAX and BAK [double knockout (DKO)]. DKO mice responded abnormally to tunicamycin-induced ER stress in the liver, with extensive tissue damage and decreased expression of the IRE1 substrate X-box-binding protein 1 and its target genes. ER-stressed DKO cells showed deficient IRE1alpha signaling. BAX and BAK formed a protein complex with the cytosolic domain of IRE1alpha that was essential for IRE1alpha activation. Thus, BAX and BAK function at the ER membrane to activate IRE1alpha signaling and to provide a physical link between members of the core apoptotic pathway and the UPR.     

MAPKK-independent activation of p38alpha mediated by TAB1-dependent autophosphorylation of p38alpha

Phosphorylation of mitogen-activated protein kinases (MAPKs) on specific tyrosine and threonine sites by MAP kinase kinases (MAPKKs) is thought to be the sole activation mechanism. Here, we report an unexpected activation mechanism for p38alpha MAPK that does not involve the prototypic kinase cascade. Rather it depends on interaction of p38alpha with TAB1 [transforming growth factor-beta-activated protein kinase 1 (TAK1)-binding protein 1] leading to autophosphorylation and activation of p38alpha. We detected formation of a TRAF6-TAB1-p38alpha complex and showed stimulus-specific TAB1-dependent and TAB1-independent p38alpha activation. These findings suggest that alternative activation pathways contribute to the biological responses of p38alpha to various stimuli.     

Stabilization of labile carbonyl addition intermediates by a synthetic receptor

Products of unfavorable chemical equilibria are not readily observed because their high energy and increased reactivity result in low concentrations. Biological macromolecules use binding forces to access unfavorable equilibria and stabilize reactive intermediates by isolating them from the medium. In a similar vein, we describe here a synthetic receptor that allows direct observation of labile tetrahedral intermediates: hemiaminals formed in the reaction of an aldehyde carbonyl group with amines. The receptor encapsulates alkyl-substituted primary amines, then orients them toward a covalently tethered aldehyde function. The hemiaminal intermediates appear at high concentration, confined from the bulk solution and observable at ambient temperature by conventional nuclear magnetic resonance spectroscopy.     

Correction of a defect in mammalian GPI anchor biosynthesis by a transfected yeast gene

Glycosylphosphatidylinositol (GPI) serves as a membrane anchor for a large number of eukaryotic proteins. A genetic approach was used to investigate the biosynthesis of GPI anchor precursors in mammalian cells. T cell hybridoma mutants that cannot synthesize dolichol-phosphate-mannose (Dol-P-Man) also do not express on their surface GPI-anchored proteins such as Thy-1 and Ly-6A. These mutants cannot form mannose-containing GPI precursors. Transfection with the yeast Dol-P-Man synthase gene rescues the synthesis of both Dol-P-Man and mannose-containing GPI precursors, as well as the surface expression of Thy-1 and Ly-6A, suggesting that Dol-P-Man is the donor of at least one mannose residue in the GPI core.