Diversity of protein inclusion bodies and identification of mosquitocidal protein in Bacillus thuringiensis subsp. israelensis

Bacillus thuringiensis subsp. israelensis produces, during sporulation, protein inclusion bodies of wide ranging sizes, all of which are toxic to mosquitoes. Two proteins are present in the smallest protein bodies (less than 0.2 micron dia.), but the number of proteins increases with increasing size of protein bodies. The largest bodies (greater than 1.5 micron dia.) contain seven proteins. All of the proteins are synthesized at different times during sporulation and are added to developing protein bodies in a stepwise manner. The protein component responsible for mosquitocidal activity is a 65,000-dalton protein, that is present in all of the protein bodies.

Separation of the cytolytic and mosquitocidal proteins of Bacillus thuringiensis subsp. israelensis

The cytolytic and mosquitocidal proteins of Bacillus thuringiensis subsp. israelensis were isolated from parasporal crystals and subsequently separated from each other. The proteins were separated by gel filtration chromatography and their molecular weights were estimated by both gel filtration chromatography and SDS-polyacrylamide gel electrophoresis. The apparent molecular weights of the mosquitocidal protein and the cytolytic protein were estimated to be 65,000 daltons and 28,000 daltons, respectively.

Expression in Escherichia coli of biologically active enzyme by a DNA sequence coding for the human plasminogen activator urokinase

We have isolated clones of Escherichia coli strain K-12 that contain a hybrid pBR322 plasmid having a 4.2-kilobase insert of a DNA transcript of the mRNA of human plasminogen activator, urokinase. The bacterially produced enzyme has properties similar to those of urokinase from human fetal kidney cells. Both enzymes occur in discrete forms ranging from 32,000 to 150,000 daltons in size. They react with antibody to purified urokinase from human kidney cells, bind to a benzamidine-Sepharose column, and induce plasminogen-dependent lysis of a fibrin clot.

Glucose binding and transport proteins extracted from fast-growing chicken fibroblasts

Preconfluent or confluent fibroblasts grown in 5% serum medium yielded, without cell lysis, all the glucose-binding protein and most of the transport-stimulating activity in the cell wash fluid obtained with a 10 mM sodium octanoate-containing solution. For assay, octanoate was removed, and after the binding protein was labeled with [(14)C]glucose, the factors were chromatographed on Sephadex G-200 and the transport-stimulating and factor-bound [(14)C]glucose activities were measured. Three peaks were separated, which more or less overlapped for both functions; upon chromatography on DEAE-cellulose, these peaks yielded overlapping or separate peaks for the two functions, presumably indicating their separability. Serum, when similarly chromatographed, showed only peaks for transport which, with the exception of one major peak with both functions, more or less overlapped with those from the wash fluid. Glucose transport rates, when compared in fibroblasts grown in glucose and in fructose and in Rous sarcoma virus-transformed cells grown in glucose, were in the proportion of 1:3.7:6.3. Addition of extracted transport protein stimulated the transport of both the glucose-grown and fructose-grown normal cells but showed no effect on the transport of transformed cells. Addition of transport protein induced the formation of [(14)C]deoxyglucose 6-phosphate in amounts proportional to the increased transport of [(14)C]deoxyglucose into fibroblasts. On sodium dodecyl sulfate electrophoresis, using the tightly bound [(14)C]glucose for assay, purified binding protein yielded large fractions of 36,000 and 18,000 and small ones of 55,000 and 73,000 daltons; the 18,000-dalton fraction is supposedly the monomeric form of the binding protein.

Isolation of amino acid activating subunit--pantetheine protein complexes: their role in chain elongation in tyrocidine synthesis

Dissociation of the multienzymes of tyrocidine synthesis by prolonged incubation of crude extracts of Bacillus brevis (Dubos strain, ATCC 8185) has yielded, on Sephadex G-100 chromatography, two fractions of amino acid activating subunits, a larger one of 70,000 daltons and a smaller one of 90,000 daltons; the latter was a complex consisting of the 70,000 dalton subunit and the pantetheine-carrying protein of about 20,000 daltons. When it dissociated, the intermediate enzyme, which activates three amino acids, contained two-thirds of the subunits in the 70,000 dalton and one-third in the 90,000 dalton fraction; the heavy enzyme, which activates six amino acids, contained five-sixths of the subunits in the former fraction and one-sixth in the latter. Both fractions showed ATP-PP(i) exchange with all amino acids that are activated by the respective polyenzymes. With proline as an example, the 70,000 dalton subunit exhibited a single low-affinity binding site, which should correspond to the peripheral thiol acceptor site, whereas the 90,000 dalton subunit showed both a low-affinity binding site and an additional high-affinity site for proline; the high-affinity site is attributed to the pantetheine present on the pantetheine-carrying protein, and suggests that amino acids are translocated from the peripheral SH to the pantetheine-carrying moiety during chain elongation. This was confirmed by the observation that the 90,000 dalton complex, when incubated with the light enzyme in the presence of phenylalanine and proline, produced DPhe-Pro dipeptide that cyclized into DPhe-Pro diketopiperazine, but the 70,000 dalton activating subunit, when similarly incubated, did not. After subunit dissociation, however, no further elongation occurred after the transfer from phenylalanine to proline.

Isolation from normal and Rous sarcoma virus-transformed chicken fibroblasts of a factor that binds glucose and stimulates its transport

A glucose binding fraction was obtained by sucrose gradient centrifugation and Sephadex G-200 chromatopgraphy from confluent normal cells and Rous sarcoma virus-transformed fibroblasts. It was more or less loosely bound to the membrane fraction, most strongly in sarcoma cells, and most loosely in slowly growing confluent fibroblasts. In an average of three determinations, the content of binding factor was increased 2.5-fold in transformed cells, and compared reasonably well to a nearly 4-fold increase in glucose uptake. The addition of 5 mug/ml of purified glucose binding factor to the overlaying fluid in the 100-mm plates increased 7-flod the low glucose uptake of starved fibroblasts. The stimulation was an additive increment to the known stimulation by calf serum.

The relation between sporulation and the induction of antibiotic synthesis and of amino acid uptake in Bacillus brevis

The induction and localization of tyrocidine-synthesizing enzymes is shown to be parallel, during growth of Bacillus brevis (ATCC 8185, American Type Culture Collection, Rockville, Md.), with the induction of uptake of constitutive amino acids and of components of pantetheine, a coenzyme of tyrocidine synthesis. Antibiotic synthesis appears at the end of logarithmic growth when the first soluble enzymes may be obtained from homogenates. During this period, binding proteins for metabolite uptake were isolated by intensive sonication which, when studied by chromatography, were identified by the appearance of low molecular weight fractions binding the radioactively marked metabolites; their induction was prevented by addition of rifampicin. The major purpose of this study was a comparison of antibiotic production and sporulation, the progress of which was followed by electron microscopy. The onset of tyrocidine synthesis and metabolite uptake coincided with the appearance of septum formation indicating that sporulation had progressed to stage II. With the progress of spore encapsulation, the tyrocidine production migrated from the soluble fraction into the forespore, terminating with the separation of forespores from the sporangium membrane. The resulting concentration of antibiotic in the forespore may indicate its function in sporulation, the nature of which, however, was not explored.

Protein kinase and its regulatory effect on reverse transcriptase activity of Rous sarcoma virus

We have studied the effect of protein phosphokinase (EC 2.7.1.37; ATP:protein phosphotransferase) and phosphoprotein phosphatase (EC 3.1.3.16; phosphoprotein phosphohydrolase) on reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity of Rous sarcoma virus. Protein kinase from Rous sarcoma virus-transformed chick embryo fibroblasts was purified by DEAE-cellulose chromatography, Sephadex gel filtration, and isoelectric focusing. Purified reverse transcriptase from Rouse sarcoma virus was preincubated with protein kinase and ATP under conditions allowing incorporation of phosphate into substrate protein. After the preincubation, reverse transcriptase activity was assayed in the presence of poly(rA).oligo(dT) as template. A 2- to 5-fold increase of reverse transcriptase activity was found after the preincubation of reverse transcriptase with protein kinase and ATP. Incubation of reverse transcriptase with heat-treated, inactive protein kinase and ATP had no effect on transcriptase activity. When the transcriptase preparation was incubated with protein kinase and [gamma-32P]ATP and subsequently purified by chromatography on phosphocellulose and Sephadex gel filtration, significant amounts of 32P-labeled proteins were found in the fractions exhibiting reverse transcriptase activity, suggesting 32P incorporation into transcriptase or transcriptase-associated proteins. A 20-60% decrease of reverse transcriptase activity was observed after incubation of reverse transcriptase with phosphatase. The results suggest that phosphorylative modification of reverse transcriptase may be critical in the regulation of reverse transcriptase-catalyzed DNA synthesis.

Influence of thyrotropin-releasing hormone on the postmenopausal female

Daily blood samples were obtained from 5 postmenopausal patients for 21 days and analyzed for plasma follicle stimulating hormone (FSH), luteinizing hormone (LH), estrone, estradiol, progesterone, and serum T4. On days 8 through 14, oral thyrotropin-releasing hormone (TRH) was administered, 50 mg, 4 times a day. All patients showed asignificant T4 response. There was, however, no significant change in the plasma FSH, LH, estrone, estradiol, or progesterone. We conclude that oral administration ofTRH has no influence on the elevated circulating concentration of FSH and LH seen in the postmenopausal female.

Isolation of a peptidyl-pantetheine-protein from tyrocidine-synthesizing polyenzymes

The polyenzyme complex responsible for the synthesis of tyrocidine in Bacillus brevis (ATCC 8185) was found to contain 4'-phosphopantetheine, which appeared to be connected with the production of growing peptide chains. Confirmation of this assumption has now been obtained by purifying from bacterial lysates a polyenzyme-dissociation product; this was labeled with [(14)C]pantothenic acid and peptide chains containing tritiated amino acids, and had a molecular weight of 17,000. To obtain these results, organisms were grown udner conditions favorable for incorporation of radioactive pantothenic acid into tyrocidine-synthesizing enzymes. A crude lysate of the [(14)C]pantothenic acid-labeled organisms was preincubated with the tritiated amino acids to form enzyme-bound growing peptide chains. The doubly labeled fragments were purified from the polyenzyme-dissociation products produced by prolonged lysis. In a second set of experiments, the three enzymes responsible for tyrocidine synthesis, including the two polyenzymes containing pantetheine, were purified and incubated with radioactive amino acids and ATP to form polyenzyme-bound peptide chains. Thereupon, a Triton X-100 extract of the 20,000 x g fraction of crude homogenate was added to dissociate the purified polyenzymes. The dissociation products were purified and yielded, on dodecyl sulfate gel electrophoresis, peptidyl-marked products ranging in molecular weight from 90,000 to 17,000, the latter being most abundant. Electrophoresis of analogous preparations after preincubation with higher concentrations of dodecyl sulfate and dithiothreitol at 100 degrees yielded a single product of 17,000 molecular weight, indicating that the larger molecular weight fractions were aggregates thereof.