Translocation of nucleolar phosphoprotein B23 (37kDapI 5.1) induced by selective inhibitors of ribosome synthesis

To elucidate the possible role of nucleolar phosphoprotein B23 in ribosome synthesis, drugs which inhibit the processing of ribosomal RNA were employed. After treatment with actinomycin D, toyocamycin or high doses of α-amanitin, a uniform nucleoplasmic fluorescence was observed. Low doses of α-amanitin and the protein synthesis inhibitor puromycin and cycloheximide had no effect on protein B23 translocation. By ELISA immunoassay, there was a 60% decrease in the amount of protein B23 in the nucleoli of the actinomycin D-treated cells as compared with the control nucleoli. Conversely, the amount of protein B23 in the nucleoplasm (excluding nucleoli) was 3-fold higher in the actinomycin D-treated cells. Preribosomal ribunucleoprotein particles (pre-rRNPs) were extracted from isolated nucleoli of Novikoff hepatoma ascites cells and fractionated on sucrose density gradients. Protein B23 was found co-localized with the pre-rRNPs as determined by ELISA assays which agrees with previous studies. The proteins in these 80 S and 55 S pre-ribosomal ribonucleoprotein particles were fractionated by 10% gel electrophoresis. Immunoblots showed protein B23 was present in both pre-rRNPs.     

Aspergillus terreus and its toxic metabolites as a food contaminant in some Egyptian Bakery products and grains

A. terreus isolates isolated from some bakery products, corn and rice were found to be able to produce territrems. 90% of theA. terreus isolated from bakery products were able to produce territrem A, with a mean of 0.09 ppm, while 80% ofA. terreus isolates produce territrem B with a mean of 0.24 ppm. On the other hand 31.8% of the isolates ofA. terreus from corn were able to produce territrem A with a mean of 0.44 ppm. ConcerningA. terreus isolates from rice, 66.7% were found to produce territrem A, with a mean of 5.28 ppm, and 77.8% of the isolates produced territrem B with a mean of 1.79 ppm.     

Expression of GABA transaminase immunoreactivity in interneurons of the rat neostriatum

Immunoreactivity for γ-aminobutyric acid transaminase (GABA-T), a degradation enzyme for GABA, was localized by immunocytochemistry in the rat neostriatum and the globus pallidus using a monoclonal antibody. Immunoreactivity for GABA-T was found primarily in interneurons and in the neuropilar elements in the neostriatum. Many of GABA-T-immunoreactive neurons were found to display parvalbumin immunoreactivity. This indicates many of the GABA-T-immunoreactive neurons are striatal GABAergic interneurons. Occasionally, GABA-T-immunoreactive glial cells were found. In the globus pallidus, many pallidal neurons also displayed GABA-T immunoreactivity and many of the immunoreactive neurons were seen to express parvalbumin immunoreactivity. Immunoreactivity for GABA-T was also detected in the neuropil of the globus pallidus. The present results indicate the GABAergic interneurons in the neostriatum and a subpopulation of pallidal neurons play an important role in metabolic degradation of GABA in the basal ganglia.     

间接免疫荧光鉴别奶牛胚胎性别的研究

本实验用H—Y抗体的间接免疫荧光方法对奶牛6—7日龄胚胎进行性别鉴别。用数排卵法获得的胚胎,共选37枚在含H—Y抗血清的M2培养液中温育30min,用M2培养液清洗后,在含FITC—荧光标记的羊抗鼠IgG二抗的M2中温育30min,经洗后的胚胎在Nikon倒置荧光显微镜下鉴别有无荧光,结果21枚胚胎有特异免疫荧光,判作雄性胚胎;16枚无特异免疫荧光,判作雌性胚胎,分别占57％和43％。这与自然出生公母犊各约50％和性比率无显著差别(P>0.25),判定为雄性的5枚胚胎移植给3头受体奶牛(每头移植1或2枚)、3枚判定为雌性胚胎移植给2头受体奶牛一头移植一枚,枚、另一头移植2枚)移植后两个月时检查有3头受体怀孕,其中,一头移植有荧光胚胎的受体返植无荧光胚胎的2头受体各产一母犊(体重皆41kg)。     

Purification and properties of a homodimeric protocatechuate 4,5-dioxygenase from Rhizobium leguminosarum

Protocatechuate 4,5-dioxygenase has been purified 100-fold from 4-hydroxybenzoate grown cells of Rhizobium leguminosarum biovar viceae. The purification yielded a homogeneous preparation with specific activity of 321 Units · mg^-1 protein. The molecular weight of the homodimeric native protein was 120,000, with subunit molecular weight of 62,000. The optimum pH for catalytic activity was 9.5 and the K _m for protocatechuate was 20 M. Physical and catalytic properties of the R. leguminosarum protocatechuate 4,5-dioxygenase were different from the published characteristics of isofunctional enzymes from Pseudomonas paucimobilis and Comamonas testosteroni.Abbreviations P45D protocatechuate 4,5-dioxygenase - CAPS 3-[Cyclohexylamino]-1-propanesulfonic acid A preliminary account of this work was presented at the 93rd General Meeting of the American Society for Microbiology, Atlanta, GA, 1993.     

Purification and Properties of Catechol 1,2-Dioxygenase from Rhizobium leguminosarum biovar viceae USDA 2370

The catechol 1,2-dioxygenase of Rhizobium leguminosarum biovar viceae USDA 2370 was purified 296-fold, yielding a homogeneous preparation with a specific activity of 51.1 U mg of protein^-1. The molecular weight of the native protein was 70,000, with two identical subunits of 34,500 and 1 g-atom of iron per mol. The optimum pH for catalytic activity was 9.0 to 9.5.     

Opioid Receptors in Magnesium-Digitonin-Solubilized Rat Brain Membranes Are Tightly Coupled to a Pertussis Toxin-Sensitive Guanine Nucleotide-Binding Protein

Opioid receptors solubilized in Mg2+-digitonin (2%, wt/vol) from Mg2+-pretreated rat brain membranes maintain, in addition to high-affinity opioid agonist binding, the modulation by guanine nucleotides. One of the modes of expression of the latter property is an attenuation of agonist binding by guanine nucleotides in the presence of Na+. To investigate the molecular basis of this modulation and to identify the G protein(s) involved, the soluble receptors were [32P]ADP-ribosylated by means of Bordetella pertussis toxin and subjected to molecular size exclusion chromatography. In addition, soluble extracts were chromatographed on lectin and hydrophobic affinity columns. The binding of 35S- and 3H-labelled analogues of GTP was also monitored in the species separated. The oligomeric G protein-coupled opioid receptors and the guanine nucleotide/pertussis toxin-sensitive species showed similar chromatographic properties in all three systems. This indicates that the biochemically functional G protein-opioid receptor complex formed in Mg2+-pretreated membranes in the absence of an agonist is stable in digitonin solution and to chromatographic separation. Further analysis showed that the guanine nucleotide modulation of opioid receptors is via the pertussis toxin substrates with Mr of 41,000 and 39,000, which are identified as Gi and Go alpha subunits, respectively.     

Probabilistic Assessment of Industrial Synergistic Systems

A probability‐based method is presented for assessing the reliability of synergistic systems and their ability to cope with the uncertainties often associated with two of a company's main types of activities: those carried out by the manufacturing department, and those carried out by the storage department. This method is based on a model focusing on the dynamic simulation of synergistic flows in terms of the mass balance. It differs from previous material flow analysis tools, which do not take into account the temporary failures occurring at the companies involved and the resulting loss of production capacity. The failure events occurring at any of the companies in a synergistic system may result in various levels of synergy failure and a short supply of resources for other companies. We therefore propose to identify the main factors responsible for a lack of synergy. We developed a dynamic stock simulation model for assessing the reliability of synergistic systems as well as that of the individual companies of a system before and after a synergy is set up. We first confirm the validity of this model by comparing the results with those based on the binomial theorem in system reliability analysis, and we then apply the model to the case of an industrial system. We conclude that companies involved in a synergistic system will inevitably be exposed to a higher risk of resource shortage because of the unsteady synergistic and outsourcing flows on which they depend. More efficient stock management methods would prevent the occurrence of the risks often associated with synergistic flows.