Crystallization of the complex of human IFN-γ and the extracellular domain of the IFN-γ receptor

A complex of human interferon-γ (IFN- γ) with the soluble extracellular domain of the IFN- γ receptor α-chain (IFN-γ-R) has been crystallised. Crystals of the complex were grown using PEG 4000 as the precipitating agent in the presence of β-octyl glucoside. The receptor-ligand complex crystallizes in a monoclinic space group and diffracts to about 3.0 Å resolution. Isomorphous crystals have been obtained with complex containing selenomethionine and cysteine mutants of IFN-γ, which may facilitate the ongoing X-ray structure determination. © 1995 Wiley-Liss, Inc.     

Immunohistochemical localization of cytochrome P450 3A in human pulmonary carcinomas and normal bronchial tissue

The cytochrome P450 (CYP) enzymes metabolize drugs and other xenobiotics in liver and also in some extrahepatic tissues. We have studied the expression and localization of CYP3A in primary lung tumours and normal lung tissue from the same patients. Thirtytwo patients undergoing partial or total lung resection for therapy of primary pulmonary carcinoma were included in this study. Immunohistochemical staining for CYP3A was performed with a modification of the ABC technique. Eight of the 32 cases of primary pulmonary carcinoma showed expression of CYP3A. In 12 of the 32 cases of normal tissue, the seromucous glands were positive for CYP3A. The bronchial epithelium was positive for CYP3A in 11 cases. We observed no correlation between CYP3A expression in tumour tissue and that in seromucous glands or bronchial epithelium. We conclude that CYP3A is present in both normal and cancerous lung tissue. Our findings suggest, however, no co-expression of CYP3A in lung cancer.     

Developmental regulation of presence of binding sites for neoglycoproteins and endogenous lectins in various embryonic stages of human lung,liver and heart

Protein-carbohydrate interactions are supposed to play key roles in the mechanisms of cell adhesion, biosignalling and intracellular routing, warranting the analysis of the developmental course of expression of epitopes of this system. Thus, a panel of carrier-immobilized carbohydrate ligands was used as probes, namely lactose,N-acetylgalactosamine,N-acetylglucosamine, mannose, fucose and maltose. Additionally, an antibody to an endogenous -galactoside-binding lectin (anti-galectin-1), the biotinylated lectin and two further human lectins, namely the macrophage migration inhibitory factor-binding sarcolectin and serum amyloid P component (SAP) that displays selectivity for sulphated sugars and mannose-6-phosphate, were included. They enabled us to assess the extent of the presence of respective binding sites in fixed sections from human lungs (pulmonary epithelial cells), livers (hepatocytes) and hearts (myocard cells) of 10–50 weeks gestation. Invariably, specific binding was detected in the three organ types, at least in certain stages. In most of the cases, the intensity of staining exhibited developmental regulation. The apparent patterns reveal similarities between the different cell types, as seen with immobilizedN-acetylglucosamine as well as with labelled galectin-1 and sarcolectin. However, drastic differences among such patterns with nearly opposite developmental courses do also occur, as detected for carrier-attached mannose and maltose residues. These results point to a potential importance for the detected glycohistochemical features in human development and substantiate the possibility of differential regulation of the presence of binding sites for distinct sugars within a certain organ and between the individual cell types of the monitored organs.     

Genetic analysis of the yeastCandida maltosa by means of induced parasexual processes

The usefulness of hybridization by protoplast fusion and mitotic segregation for the genetic analysis of the imperfect fodder yeastCandida maltosa was tested. Mitotically stable fusion hybrids were obtained with frequencies between 10^–6 and 10^–7. Complementation tests were performed by protoplast fusion. Substances that are known to induce frequent mitotic segregation in other yeast species such as benomyl, p-fluorophenylalanine, and acriflavine were ineffective inC. maltosa. UV irradiation induced mitotic segregation in up to 10%. This agent induced mainly mitotic crossing over inC. maltosa. Our data enabled the construction of the linkage group I with the sequenceCEN-ade-26-pro-1.     

Elastases from human and canine granulocytes, II. Interaction with protease inhibitors of animal, plant, and microbial origin.

Inhibitors of animal, plant, and microbial origin were tested against human and canine granulocytic elastases. The trypsin-chymotrypsin inhibitors from dog submandibular glands, from soybeans (Bowman-Birk) and from chickpeas show strong interaction with these proteases (Ki = 10(-8) - 10(-9)M). The trypsin-kallikrein inactivator of bovine organs (Trasylol) is not active against granulocytic elastases or against human granulocytic cathepsin G. Elastatinal, a specific inhibitor of elastases, isolated from actinomycetes (Streptomyces griseoruber), forms stable complexes with elastase from human (Ki = 6.2 X 10(-6)M) and canine granulocytes (Ki = 1.1 X 10(-6)M). A possible therapeutic application of these inhibitors for the inactivation of granulocytic proteases, which are able to degrade connective tissue in different pathological states, is discussed.     

The conversion of [3H] tryptophan to 5-[3H] hydroxytryptamine in mouse brain following depletion of phenylalanine and tyrosine.

Abstract— Phenylalanine ammmonia-lyase (PAL), an enzyme which converts phenylalanine (Phe) and tyrosine (Tyr) to trans-p-cinnamic acid and trans-p-coumaric acid, respectively, was administered to mice and its effect on the conversion of [³H]tryptophan to 5-[³H]HT in the brain was measured. Although PAL significantly depleted plasma Tyr, it has little or no effect on either brain Tyr or catecholamine concentrations. Endogenous brain tryptophan levels were significantly increased 2 h after PAL administration, brain 5-HT was dramatically increased 4 h following PAL and each returned to baseline levels by 8 h. This return to baseline was accompanied by a marked decrease in the fraction of tryptophan converted to 5-HT during a 20 min pulse period preceding death, suggesting the activation of a compensatory decrease in 5-HT synthesis in response to increased 5-HT concentration. These data suggest that PAL administration readily produces reversible alterations in 5-HT synthesis and that this may be a fruitful approach to studying brain 5-HT function.     

Integration specificity of an artificial kanamycin transposon constructed by the in vitro insertion of an internal Tn5 fragment into IS2

Molecular Genetics and Genomics - IS2 has been marked genetically by the in vitro insertion into its HindIII site of a 3.3 Kb HindIII fragment of Tn5 conferring resistance to kanamycin. The...     

The influence of externally supplied sucrose on phloem transport in the maize leaf strip

Sucrose (2,5–1000 mmol l^–1), labeled with [¹⁴C]sucrose, was taken up by the xylem when supplied to one end of a 30-cm-long leaf strip of Zea mays L. cv. Prior. The sugar was loaded into the phloem and transported to the opposite end, which was immersed in diluted Hoagland's nutrient solution. When the Hoagland's solution at the opposite end was replaced by unlabeled sucrose solution of the same molarity as the labeled one, the two solutions met near the middle of the leaf strip, as indicated by radioautographs. In the dark, translocation of ¹⁴C-labeled assimilates was always directed away from the site of sucrose application, its distance depending on sugar concentration and translocation time. When sucrose was applied to both ends of the leaf strip, translocation of ¹⁴C-labeled assimilates was directed toward the lower sugar concentration. In the light, transport of ¹⁴-C-labeled assimilates can be directed (1) toward the morphological base of the leaf strip only (light effect), (2) toward the base and away from the site of sucrose application (light and sucrose effect), or (3) away from the site of sucrose application independent of the (basipetal or acropetal) direction (sucrose effect). The strength of a sink, represented by the darkened half of a leaf strip, can be reduced by applying sucrose (at least 25 mmol l^–1) to the darkened end of the leaf strip. However, equimolar sucrose solutions applied to both ends do not affect the strength of the dark sink. Only above 75 mmol l^–1 sucrose was the sink effect of the darnened part of the leaf strip reduced. Presumably, increasing the sucrose concentration replenishes the leaf tissue more rapidly, and photosynthates from the illuminated part of the leaf strip are imported to a lesser extent by the dark sink.Supported by Deutsche Forschungsgemeinschaft