Synthesis of the dodecapeptide-alpha mating factor of Saccharomyces cerevisiae

The synthesis of His-Trp-Leu-Gln-Leu-Lys-Pro-Gly-Gln-Pro-Met-Tyr, the dodecapeptide alpha-mating factor from Saccharomyces cerevisiae, and its Ala2- and Cha2-(beta-cyclohexylalanine) analogs are reported. Peptides were synthesized in solution using a combination of mixed anhydride and 1-hydroxybenzotriazole accelerated active ester coupling procedures. Dilute methanesulfonic acid (0.1-0.2 M) in methylene chloride-formic acid solution was employed to specifically remove the tert.-butoxycarbonyl group in the presence of the benzyloxycarbonyl group. Free peptides were obtained using catalytic transfer hydrogenation with formic acid as the hydrogen donor followed by mild acidolysis with trifluoroacetic acid. The alpha-factor and the Cha2-analog exhibited almost equal ability to cause "shmooing" of a-mating types of S. cerevisiae whereas the Ala2-analog exhibited no activity in this assay. These results differ with structure-activity studies reported on the tridecapeptide alpha-factor.

Terminal nucleotide sequences of Tn551, a transposon specifying erythromycin resistance in Staphylococcus aureus: homology with Tn3

The erythromycin resistance determinant of Staphylococcus aureus plasmid pI258 resides on a 5.3 kb transposon, Tn551. We have determined DNA sequences surrounding the junctions between the transposon and the flanking DNA in the wild-type plasmid, in an insertion into a second plasmid, and in two transposon-related deletions. The ends of the transposon consist of an inverted repeat of 40 base pairs flanked by a direct repeat of 5, thus placing the transposon in the same class as Tn3, IS2, Tn501, gamma delta, and bacteriophage Mu. Interestingly, we find that the terminal sequences of the 40 base pairs inverted repeat are very similar to the ends of Tn3, a transposon which one would not have expected to show any relation to Tn551. This result suggests common ancestry for Tn3 and Tn551. The inverted repeat sequence of Tn551 also contains (with one additional inserted base) the internal heptanucleotide sequence which has been found to be common to most of the transposable elements that generate 5-base pair direct repeat sequences.

A new system for studying molecular mechanisms of mutation by carcinogens

A new system for studying the molecular mechanisms of mutation by carcinogens is described. The system involves (a) site-specific modification of the essential gene G in phi X174 replicative form DNA by a combination of chemical and enzymatic steps; (b) production of mutant virus carrying a change at a single preselected site by transfection of spheroplasts with the site modified phi X174 DNA; (c) detection and propagation of mutants using a host carrying the plasmid, p phi XG, that rescues all type of gene G mutants by complementation; (d) identification of the mutation in the progeny virus by isolating and sequencing mutant phi X174 DNA in the region that carried the parental, site-specific change. To demonstrate that this system is operational, we have produced a previously unknown phi X174 gene G mutant carrying a C leads to T base change at position 2401 of the viral (plus) strand. This preplanned, nonsense (amber) mutant was obtained by changing G to A at the appropriate position in a chemically synthesized, octadeoxynucleotide, minus strand primer; elongating this enzymatically with Escherichia coli DNA polymerase I (larger fragment) (lacking 5' leads to 3' exonuclease activity) to a 17-mer; and repriming to obtain the site-modified phi X174 replicative form DNA enzymatically with E. coli DNA polymerase I (large fragment) and T4 DNA ligase. After transfection of spheroplasts with the heteroduplex DNA, the lysate was screened for mutant virus with permissive (carrying p phi XG) and nonpermissive (without p phi XG) host cells. About 1% of the progeny virus were mutants. Out of 15 isolates, 11 were suppressible by an amber Su1+ (serine) or an ochre Su8+ (glutamine) suppressor. The other 4 isolates were not suppressed at all. Replicative form DNA produced from one of the suppressible mutants was shown (by sequencing) to contain the expected C leads to T change at the preselected site in the viral strand. Replicative form DNA from one of the nonsuppressible mutants was partially sequenced. No change was found at or around position 2401. The nature of the mutation(s) in these isolates is still unknown. The occurrence of mutations outside the preselected sites represent a potential problem for our projected studies, but additional data is required before the problem can be fully evaluated. In spite of this, it should be possible to study, in vivo, the biological effects of any site-specific modification (including covalent modifications by carcinogens) that can be introduced into gene G of phi X174 DNA via a synthetic, oligonucleotide primer.

Solid-phase synthesis of oxytocin, desaminooxytocin and 4-Thr-oxytocin using active esters in presence of 1-hydroxybenzotriazole

Using appropriate amino acid active esters (3 eq.) in presence of HOBt (1 eq.) and employing DPM protection for the thiol function of cysteine, a rapid synthesis of oxytocin in the solid phase has been accomplished. The DPM group has been removed by sodium-liquid ammonia reduction since boiling TFA is ineffective. Desaminooxytocin and 4-Thr-oxytocin have been synthesized using lesser quantities of amino acid active esters (1.5 eq.) in presence of HOBt (1 eq.), but the durations of coupling are longer. The solid-phase synthesis of desamino-oxytocin using appropriate Boc-amino acids in presence of DCCI in toluene medium has been described. Toluene does not exert any significant accelerating influence on the coupling rate as it does when active esters are employed.

High terminal deoxynucleotidyl transferase activity in pediatric patients with acute lymphocytic and acute myelocytic leukemias

Specificity of TdT5 as a marker for ALL was evaluated by determining its activity in cells from normal control subjects and from 35 pediatric patients with ALL, AML, Hodgkin's disease and disseminated Burkitt's lymphoma. We evaluated the DNA polymerase activity, cell surface phenotypes (E rosettes, EAC rosettes, Smlg and la-like, HTLA and cALL antigens), and hematological and cytochemical characteristics in both the normal and patient groups. DNA polymerase alpha + beta and DNA polymerase gamma activity were indiscriminately high in all immature cells as found in ALL, AML, Burkitt's lymphoma and phytohemagglutinin-stimulated normal lymphocytes, when compared to mature leukocytes found in normal individuals or in patients whose cancer was in remission. High TdT activity was found in 24 of 26 T and non-T/non-B ALL patients in active phase as well as in two of three AML patients one of whom had Auer rods. Thus, TdT, although valuable for monitoring ALL patients, may have limitations in separating AML from ALL.

Antibodies specific to two deoxyribotrinucleotide sequences

Antibodies to the deoxyribotrinucleotides dpApTpA and dpApApT were prepared by injecting the bovine serum albumin conjugates of the respective haptens in rabbits. The specificities of the antibodies were determined by estimating the inhibition of the binding of the tritiated haptens to the immunoglobulins by various nonradioactive mono- and oligonucleotides, using nitrocellulose membrane binding assay. Anti-dpApTpA and anti-dpApApT antisera were found to contain antibodies which were highly specific to the respective hapten sequence.

Antibodies specific to a deoxyribodinucleotide sequence

Antibodies were raised in rabbits against the bovine serum albumin conjugate of dpApT. Analysis by double diffusion in agar gel and quantitative precipitation test showed the presence of antibodies specific to the hapten in the antisera. Quantitative data on the specificity of the antibodies were obtained by studying the inhibition of the binding of 3H-dpApT to the antisera by various nonradioactive mono- and oligonucleotides, using a nitrocellulose membrane binding assay. The antibodies were found to be highly specific for the dinucleotide sequence dpApT. The antibodies were able to bind to synthetic oligonucleotides containing the sequence dpApT and to denatured calf thymus DNA.

A double-blind comparison of 1% hydrocortisone plus 10% urea ('Alphaderm') and 0.1% betamethasone 17-valerate in the treatment of non-infective inflammatory dermatoses

A double-blind controlled trial was carried out over a period of 3 weeks to assess the effectiveness of 1% hydrocortisone, in a specialized carbamide drug delivery system, compared with 0.1% betamethasone 17-valerate cream in the treatment of 21 patients with bilateral, symmetrical, non-infective inflammatory dermatoses. The trial preparations were applied topically twice daily, each to one side only during the trial. Although overall patient preference tended to favour betamethasone 17-valerate, the physician's assessment of clinical improvement, based on severity rating scores, indicated that both preparations were equally effective and there were no significant differences between the calculated mean percentage clinical improvements at the end of each week.

High terminal deoxynucleotidyl transferase activity in acute myelogenous leukemia

Although leukocytes from all 13 acute lymphoblastic leukemia patients examined had high terminal deoxynucleotidyl transferase (terminal transferase) activity (20 to 100 units/mg of cellular DNA, where 1 unit equals 1 nmole of nucleotide polymerized in 1 hr) and those from 21 acute myelocytic leukemia patients had low terminal transferase activity (0.2 to 2 units/mg of cellular DNA), the bone marrow and peripheral blood leukocytes from 2 patients with acute myelocytic leukemia, diagnosed on the basis of clinical features and the morphology, cytochemistry, and cytogenetics of the leukemic cells, had terminal transferase activity (39 to 52 units/mg of cellular DNA) equivalent to that found in leukemic lymphoblasts. These results bring under question the specificity of high terminal transferase activity outside of the thymus as a marker for leukemic lymphoblasts and, secondarily, the derivation of acute lymphoblastic leukemia cells in all cases from thymocytes. Perhaps malignant transformation in a pleuripotent stem cell with derepression of the genome for terminal transferase could account for high terminal transferase activity observed in certain leukemic cells.

Demonstration of antibodies to testicular basement membrane by immunofluorescence in a patient with multiple primary endocrine deficiencies

Circulating antibodies directed against testicular basement membrane and germinal cells are demonstrated in a patient with multiple primary endocrine gland deficiencies involving the thyroid, adrenals, testes, and pernicious anemia. Testicular biopsy revealed focal destruction of seminiferous tubules and interstitial fibrosis. The tubular basement membranes showed sharply positive immunofluorescence when stained with the patient's FITC conjugated gamma globulins.

cis and trans Isomers of Dihalobis(2-acetylaminothiazole)nickel(II)

The cis and trans isomers of Ni(aatz)2,X2 (X = Cl, Br, I and aatz = 2- acetylaminothiazole) have been prepared and characterized with the help of magnetic moment data and infrared and electronic spectra. The number of bands in the far infrared region (650-50 cm-1) suggests a C2h symmetry for the trans and C2v symmetry for the cis isomers. Electronic spectral bands of cis isomers have higher molar extinction coefficients and show less splitting than the trans isomers. The ligand exerts a stronger ligand field in cis than in trans isomers. The spin orbit coupling constant values (λ?) and the Bohr magneton values increase from chloro to iodo in the case of cis complexes and decrease in trans complexes. The X-ray powder pattern data for both the isomers are identical. 2- Acetylaminothiazole acts as a bidentate ligand and the donor sites are carbonyl oxygen and ring sulphur.

Further studies of competition of antigens. I. Variation in immunosuppression induced by alterations of dosage, route of injection, nature of antigen, and immunological status of host

Several characteristics of antigenic competition were studied in mice using various pairs of antigens administered in sequence. Enhanced immunosuppression of the response to the second antigen was obtained by increasing the dose of the initial antigen relative to the dose of the test antigen. Diminished immunosuppression was elicited when the dose of the second antigen was increased to near maximum levels, corresponding to the plateau of immune responsiveness to this antigen when it was administered in equivalent dosage to normal control groups of animals. Induction of a primary immune response to the initial antigen was a more effective immunosuppressant than was induction of a secondary immune response to an equivalent dose of the same antigen. Antigenic competition was manifested when antigen was administered in differing sites in the animal such as in separate footpads. Administration of the antigens in the same site did not invariably result in antigenic competition, since a combination of two intraperitoneal injections of unrelated antigens in sequence was not associated with immunosuppression of response to the test antigen. Immunosuppression by antigenic competition did not alter the affinity of the antibody product to the test antigen.

Hypothalamic-pituitary-adrenal function in patients treated with long-term depot tetracosactrin

Four patients treated with depot tetracosactrin for 10 to 18 months maintained normal hypothalamic-pituitary-adrenal function assessed by the nyctohemeral variation of plasma corticosteroids and by the responses of plasma corticosteroids to insulin-induced hypoglycaemia, lysine-vasopressin, and depot tetracosactrin. The pituitary component of the response was analysed by measuring plasma immunoreactive ACTH levels. Three patients showed a nyctohemeral ACTH rhythm and normal ACTH responses to insulin-induced hypoglycaemia. Consistently undetectable morning plasma ACTH levels were found in the fourth patient, who also showed an unusually delayed rise in both ACTH and corticosteroid levels in response to insulin-induced hypoglycaemia, though the peak values attained were normal.The lack of suppression of hypothalamic-pituitary-adrenal function together with the good clinical response in these four patients suggests that treatment with depot tetracosactrin should be considered when long-term corticosteroid therapy is required.

Autoerythrocyte sensitization syndrome

A further case of autoerythrocyte sensitization syndrome is reported and the relevant literature is briefly reviewed. It is suggested that the simple intradermal test with autologous red blood cells be performed in all cases presenting with unexplained painful bruising to avoid many unnecessary and laborious laboratory investigations.

Long-term use of depot tetracosactrin

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The effect of antigenic competition on various manifestations of humoral antibody formation and cellular immunity

The effect of antigenic competition on various parameters of humoral antibody formation and cellular immunity was studied in mice. Several pairs of antigens were employed in the investigation of the competitive aspects of induction of humoral antibody formation. Induction of a primary immune response to hemocyanin in Swiss white female mice moderately suppressed the induction of both 19S and 7S antibody formation to goose or rat erythrocytes. Suppression of 7S antibody formation was maximal when a time interval of 1-3 days separated the sequence of injections, although suppression was noted for intervals of up to 14 days. The induction of a primary immune response to rat RBC, the second of the two antigens in sequence, also suppressed The induction of both 19S and 7S antibody formation to goose RBC when appropriate intervals of 1-3 days were employed between injections. The induction of a secondary immune response to rat RBC totally suppressed the primary induction of both 19S and 7S antibody formation to goose RBC administered in the appropriate time sequence. Subsequently, it was shown that the secondary immune response to the suppressed antigen (goose RBC) elicited 30 days after induction of a primary immune response (5 days after secondary immunization with rat RBC) was characterized by deficient 19S and 7S antibody production. These levels were suppressed even in comparison with a normal primary immune response to this antigen. The results were interpreted in part on the basis of a deficiency of formation of primed cells associated with immunological memory. Alternatively, evidence was obtained for the development of a split type of immunological tolerance in 6 of 10 animals studied, since a total suppression of 7S antibody production was obtained in association with deficient 19S antibody synthesis (titers < 1/10). The induction of a primary immune response to several antigens in A/J female mice suppressed the processes of cellular immunity as manifested by prolonged survival of skin grafts from C57 BL/6J female donors. These results were interpreted as evidence for the existence and utilization of processing cells by the initial immune stimulus yielding a deficiency of cells available for processing the second antigen administered in sequence.