Balmoralmycin, a new angucyclinone, and two related biosynthetic shunt products containing a novel ring system

A new angucyclinone, named balmoralmycin (1), was isolated as an inhibitor of protein kinase C-alpha (PKC-alpha) from the Streptomyces strain P6417. Chemical screening of extracts of the same strain resulted in the detection of two decaketides with unusual structural features (2 and 3). Both compounds belong to a recently described structural class of secondary metabolites which arises from engineered biosynthesis of a recombinant Streptomyces strain. The isolation of compounds of this class from a wild-type strain has never been reported before.

Chronic respiratory symptoms associated with estimated long-term ambient concentrations of fine particulates less than 2.5 microns in aerodynamic diameter (PM2.5) and other air pollutants

Seventh-Day Adventists (SDAs), nonsmokers who had resided since 1966 in the vicinity of nine airports throughout California (n = 1,868), completed a standardized respiratory symptoms questionnaire in 1977 and again in 1987. For each participant, cumulative ambient concentrations of fine particulates less than 2.5 microns (microns) in aerodynamic diameter (PM2.5) were estimated from airport visibility data. Long-term ambient concentrations of estimated PM2.5 in excess of 20 micrograms per cubic meter (micrograms/m3) were found to be associated with development of definite symptoms of chronic bronchitis between 1977 and 1987. Estimated mean concentrations of PM2.5 were associated with increasing severity of respiratory symptoms related to general airway obstructive disease, chronic bronchitis, and asthma. It was felt that the observed relationships, with the exception of the relationship between increasing severity of chronic bronchitis symptoms and PM2.5, could be due to surrogate relationships with other ambient pollutants.

Limited and defined truncation at the C terminus enhances receptor binding and degranulation activity of the neutrophil-activating peptide 2 (NAP-2). Comparison of native and recombinant NAP-2 variants

We have previously described a C-terminally truncated variant of the chemokine neutrophil-activating peptide 2 (NAP-2) that exhibited higher neutrophil-stimulating capacity than the full-size polypeptide. To investigate the impact of the NAP-2 C terminus on biological activity and receptor binding, we have now purified the novel molecule to homogeneity. Furthermore, we have cloned, expressed in Escherichia coli, and purified full-size recombinant NAP-2 (rNAP-2-(1-70)) and a series of C-terminally deleted variants (rNAP-2-(1-69) to rNAP-2-(1-64)). Biochemical and immunochemical analyses revealed that the natural NAP-2 variant was structurally identical to the rNAP-2-(1-66) isoform. As compared with their respective native and recombinant full-size counterparts, both molecules exhibited approximately 3-4-fold enhanced potency in the induction of neutrophil degranulation as well as 3-fold enhanced binding affinity for specific receptors on these cells. All other variants were considerably less active. The natural occurrence of a NAP-2 variant truncated by exactly four residues at the C terminus suggests that limited and defined proteolysis at this site plays a role in the regulation of the biological function of the chemokine.

IL-8 specifically binds to endothelial but not to smooth muscle cells

The proinflammatory cytokine and potent chemoattractant IL-8 is involved in regulation of infectious or inflammatory processes. Human vascular endothelial cells (EC) and smooth muscle cells (SMC) probably contribute to these responses by recognition and/or production of rIL-8. We demonstrate here in competitive binding studies with radiolabeled rIL-8 that EC and fibroblasts, but not SMC, specifically bind IL-8 with low affinity. The binding was not saturated by ligand concentrations up to 80 nM 125I-rIL-8. Unlabeled neutrophil-activating peptide-2 competed the binding of 125I-rIL-8, although less potently than unlabeled rIL-8, as reported previously for polymorphonuclear neutrophils. In contrast, connective tissue-activating peptide III, platelet factor 4, or lysozyme did not reduce binding of 125I-rIL-8 to EC or fibroblasts. In accordance with these binding studies, EC and fibroblasts, but not SMC, expressed human IL-8 receptor type I mRNA. Neither cell type expressed mRNA for IL-8 receptor type II. Stimulation with IL-1 alpha or LPS did not alter the results obtained in PCR or binding studies. Although SMC did not express specific binding sites for IL-8, Western blot experiments showed that IL-1 alpha-, TNF-, or LPS-stimulated SMC released two major immunoreactive isoforms of IL-8 in a time- and dose-dependent manner. The m.w. were similar to IL-8 isoforms released by EC or mononuclear cells. The differential capacity of EC and SMC to produce IL-8 and express IL-8 binding sites indicates that vascular cell-derived IL-8 may contribute to differential regulation of infectious and inflammatory responses in the vessel wall.

Paeciloquinones A, B, C, D, E and F: new potent inhibitors of protein tyrosine kinases produced by Paecilomyces carneus. I. Taxonomy, fermentation, isolation and biological activity

Paeciloquinones A to F as well as versiconol have been isolated as inhibitors of protein tyrosine kinase from the culture broth of the fungus Paecilomyces carneus P-177. The novel anthraquinones inhibit epidermal growth factor receptor protein tyrosine kinase in the micromolar range. Two compounds, paeciloquinones A and C, are potent and selective inhibitors of the v-abl protein tyrosine kinase with an IC50 of 0.4 microM. Dependent on the fermentation conditions, partially different sets of paeciloquinones may be produced. An HPLC method allows separation of all major active components.

IL-8 specifically binds to endothelial but not to smooth muscle cells

The proinflammatory cytokine and potent chemoattractant IL-8 is involved in regulation of infectious or inflammatory processes. Human vascular endothelial cells (EC) and smooth muscle cells (SMC) probably contribute to these responses by recognition and/or production of rIL-8. We demonstrate here in competitive binding studies with radiolabeled rIL-8 that EC and fibroblasts, but not SMC, specifically bind IL-8 with low affinity. The binding was not saturated by ligand concentrations up to 80 nM 125I-rIL-8. Unlabeled neutrophil-activating peptide-2 competed the binding of 125I-rIL-8, although less potently than unlabeled rIL-8, as reported previously for polymorphonuclear neutrophils. In contrast, connective tissue-activating peptide III, platelet factor 4, or lysozyme did not reduce binding of 125I-rIL-8 to EC or fibroblasts. In accordance with these binding studies, EC and fibroblasts, but not SMC, expressed human IL-8 receptor type I mRNA. Neither cell type expressed mRNA for IL-8 receptor type II. Stimulation with IL-1 alpha or LPS did not alter the results obtained in PCR or binding studies. Although SMC did not express specific binding sites for IL-8, Western blot experiments showed that IL-1 alpha-, TNF-, or LPS-stimulated SMC released two major immunoreactive isoforms of IL-8 in a time- and dose-dependent manner. The m.w. were similar to IL-8 isoforms released by EC or mononuclear cells. The differential capacity of EC and SMC to produce IL-8 and express IL-8 binding sites indicates that vascular cell-derived IL-8 may contribute to differential regulation of infectious and inflammatory responses in the vessel wall.

Connective tissue-activating peptide III desensitizes chemokine receptors on neutrophils. Requirement for proteolytic formation of the neutrophil-activating peptide 2

The connective tissue-activating peptide III (CTAP-III), which is released from activated platelets, represents an inactive precursor of the chemokine neutrophil-activating peptide 2 (NAP-2). Leukocytes and leukocyte-derived proteases have been found to convert CTAP-III into NAP-2 by proteolytic cleavage at the N terminus. We demonstrate here that rapid and efficient formation of NAP-2 is mediated by neutrophil granulocytes (PMN) but not by monocytes or lymphocytes. However, as seen in a degranulation assay, neutrophils processing CTAP-III did not become activated by the generated NAP-2 and even exhibited decreased responsiveness to high doses of NAP-2 or IL-8, but not to FMLP. The desensitizing effect, being maximal already after 5 min of preincubation with CTAP-III, was not mediated through binding of the precursor to specific receptors but correlated with the rapid down-modulation of common NAP-2/IL-8 high affinity binding sites. A similar functional and receptor desensitization was observed in PMN pre-exposed to nonstimulatory doses of NAP-2. Specific inhibition of the CTAP-III-cleaving enzyme by the serine protease inhibitor aprotinin abrogated the CTAP-III, but not the NAP-2-mediated effects. Desensitization of PMN by CTAP-III was due to NAP-2 generated by proteolytic truncation of CTAP-III. Our results suggest that CTAP-III may regulate PMN activation by protecting processing cells from premature activation.

Connective tissue-activating peptide III desensitizes chemokine receptors on neutrophils. Requirement for proteolytic formation of the neutrophil-activating peptide 2

The connective tissue-activating peptide III (CTAP-III), which is released from activated platelets, represents an inactive precursor of the chemokine neutrophil-activating peptide 2 (NAP-2). Leukocytes and leukocyte-derived proteases have been found to convert CTAP-III into NAP-2 by proteolytic cleavage at the N terminus. We demonstrate here that rapid and efficient formation of NAP-2 is mediated by neutrophil granulocytes (PMN) but not by monocytes or lymphocytes. However, as seen in a degranulation assay, neutrophils processing CTAP-III did not become activated by the generated NAP-2 and even exhibited decreased responsiveness to high doses of NAP-2 or IL-8, but not to FMLP. The desensitizing effect, being maximal already after 5 min of preincubation with CTAP-III, was not mediated through binding of the precursor to specific receptors but correlated with the rapid down-modulation of common NAP-2/IL-8 high affinity binding sites. A similar functional and receptor desensitization was observed in PMN pre-exposed to nonstimulatory doses of NAP-2. Specific inhibition of the CTAP-III-cleaving enzyme by the serine protease inhibitor aprotinin abrogated the CTAP-III, but not the NAP-2-mediated effects. Desensitization of PMN by CTAP-III was due to NAP-2 generated by proteolytic truncation of CTAP-III. Our results suggest that CTAP-III may regulate PMN activation by protecting processing cells from premature activation.

Production of cladospirone bisepoxide, a new fungal metabolite

Cladospirone bisepoxide (1), a novel metabolite, was isolated from cultures of a fungus which was characterized as a coelomycete by the formation of pycnidia. By optimization of media and fermentation conditions, a titer of up to 1.5 g/liter on shake level and 1.16 g/liter on bioreactor scale could be achieved. The isolation of the compound was performed by solvent extraction of the culture broth and subsequent crystallization. Cladospirone bisepoxide displays selective antibiotic activity against several bacteria and fungi and inhibits germinations of Lepidium sativum at low concentrations.

Neutrophil-activating peptides NAP-2 and IL-8 bind to the same sites on neutrophils but interact in different ways. Discrepancies in binding affinities, receptor densities, and biologic effects

IL-8 and the neutrophil-activating peptide 2 (NAP-2) are members of the chemokine family of host defense cytokines. Although IL-8 was shown to interact with two different high affinity receptors on polymorphonuclear neutrophil granulocytes (PMN), direct demonstration of specific binding sites for NAP-2 is difficult, because the NAP-2 molecule lacks iodinable side chains. Here we present a modified labeling procedure for the chemokine that does not affect its biologic activity. The 125I-labeled NAP-2 specifically bound to PMN with two different affinities (KD = 0.65 and 22.4 nM). We observed complete cross-competition of unlabeled IL-8 with 125I-labeled-NAP-2 and of unlabeled NAP-2 with 125I-labeled IL-8, indicating the absence of monospecific binding sites for either chemokine. However, in contrast to former work by others, the total number of accessible sites was considerably lower for NAP-2 (13,000/cell) than for IL-8 (59,000/cell). In addition, PMN prepared from heparinized blood expressed significantly more receptors for NAP-2 than cells prepared from citrated blood, whereas receptor numbers for IL-8 were unchanged. Desensitization experiments suggested a regulatory role for the NAP-2 high affinity site. Short-term priming of PMN with a nonstimulatory dose of NAP-2 (or MGSA) but not with IL-8 led to drastic down-regulation of the subsequent degranulation response, challenged by higher dosages of NAP-2, MGSA, or IL-8. Reduced functional responsiveness of cells correlated with the rapid down-regulation and internalization of NAP-2 and IL-8 high affinity binding sites. Thus, our data indicate that chemokines could mediate by individual modes of interaction with common receptor's different biologic functions.

Neutrophil-activating peptides NAP-2 and IL-8 bind to the same sites on neutrophils but interact in different ways. Discrepancies in binding affinities, receptor densities, and biologic effects

IL-8 and the neutrophil-activating peptide 2 (NAP-2) are members of the chemokine family of host defense cytokines. Although IL-8 was shown to interact with two different high affinity receptors on polymorphonuclear neutrophil granulocytes (PMN), direct demonstration of specific binding sites for NAP-2 is difficult, because the NAP-2 molecule lacks iodinable side chains. Here we present a modified labeling procedure for the chemokine that does not affect its biologic activity. The 125I-labeled NAP-2 specifically bound to PMN with two different affinities (KD = 0.65 and 22.4 nM). We observed complete cross-competition of unlabeled IL-8 with 125I-labeled-NAP-2 and of unlabeled NAP-2 with 125I-labeled IL-8, indicating the absence of monospecific binding sites for either chemokine. However, in contrast to former work by others, the total number of accessible sites was considerably lower for NAP-2 (13,000/cell) than for IL-8 (59,000/cell). In addition, PMN prepared from heparinized blood expressed significantly more receptors for NAP-2 than cells prepared from citrated blood, whereas receptor numbers for IL-8 were unchanged. Desensitization experiments suggested a regulatory role for the NAP-2 high affinity site. Short-term priming of PMN with a nonstimulatory dose of NAP-2 (or MGSA) but not with IL-8 led to drastic down-regulation of the subsequent degranulation response, challenged by higher dosages of NAP-2, MGSA, or IL-8. Reduced functional responsiveness of cells correlated with the rapid down-regulation and internalization of NAP-2 and IL-8 high affinity binding sites. Thus, our data indicate that chemokines could mediate by individual modes of interaction with common receptor's different biologic functions.

3-Alkanoyl-5-hydroxymethyl tetronic acid homologues and resistomycin: new inhibitors of HIV-1 protease. I. Fermentation, isolation and biological activity

In the course of a screening program for HIV-1 protease inhibiting activity, six new homologues of 3-alkanoyl-5-hydroxymethyl tetronic acids (1 approximately 6) and the known natural product resistomycin (7) were isolated from cultures of the Actinomycete strain DSM 7357. The substituted tetronic acids belong to a recently described structural class of secondary metabolites. The HIV-1 activity of resistomycin (7) has not been reported before.

Otobothrium penetrans (Cestoda; Trypanorhyncha) in the flesh of belonid fish from Philippine waters

In April 1990, 488 marine fish belonging to 30 species from central Philippine waters were examined for flesh parasitic infections that may affect their consumability. One species of hemirhamphids and 3 species of belonids harboured plerocercoids of Otobothrium penetrans Linton, 1907 (Proceedings of the U.S. National Museum 33, 85-126). This is the first record of this parasite from Pacific fish species. The highest intensity of infection found was 8 in Tylosurus crocodilus. Most of the larvae were located between the dorsal spines of the vertebral column, only 32% were found in the fillets. Based on the present material we give a description of the plerocercoid stage of the species using scanning electron microscopy of the armature and morphometrical measurements. Comparison to results from earlier findings of O. penetrans by Linton (1907; 1924, Proceedings of the U.S. National Museum 64, 1-114) and to O. kurisi by Shields (1985, International Journal for Parasitology 15: 635-643) lead to the conclusion that the latter species is a synonym for O. penetrans.

A novel molecular variant of the neutrophil-activating peptide NAP-2 with enhanced biological activity is truncated at the C-terminus: identification by antibodies with defined epitope specificity

The human neutrophil-activating peptide 2 (NAP-2) belongs to the so-called beta-thromboglobulin/interleukin 8-family of chemotactic and reparative host defense cytokines. NAP-2 represents one of several N-terminally truncated cleavage products that originate from platelet-derived precursor molecules through proteolytic processing. Among these homologous isoforms that are comprised as beta-thromboglobulin antigen (beta-TG Ag), NAP-2 is recognized as the major component, having the highest potential for the activation of polymorphonuclear neutrophils (PMN). We now present evidence that there exists a second molecular form of NAP-2 with even higher biological activity. This novel isoform was detected in concentrates of culture supernatants from peripheral blood mononuclear cells, and could be separated from authentic NAP-2 by several steps of column chromatography. It had an N-terminus identical to that of NAP-2 but was biochemically different as indicated by its slightly lower molecular weight and a higher isoelectric point. To examine our hypothesis that the polypeptide represented a C-terminally truncated variant of NAP-2, we prepared synthetic peptides that were used for the induction and characterization of two rabbit antibody fractions, directed against different and defined epitopes within the C-terminal alpha-helix of the NAP-2 molecule. Comparison of reactivity patterns of these antibodies in Western blots as well as in a NAP-2 biological assay (PMN degranulation assay) confirmed that the variant NAP-2 was truncated at its C-terminus by at least one and by maximally three residues. The specific activity of the truncated polypeptide was estimated to be about four-fold higher than that of authentic NAP-2, as determined in the PMN degranulation assay. Thus, proteolytic modification at the C-terminus appears to play a role in the regulation of NAP-2-biological activity.

Germicidin, an autoregulative germination inhibitor of Streptomyces viridochromogenes NRRL B-1551

During germination spores of Streptomyces viridochromogenes NRRL B-1551 excrete a compound, germicidin, which has an inhibitory effect on the germination of its own arthrospores at a concentration as low as 200 pM (40 pg/ml). At higher concentrations germicidin inhibits porcine Na+/K(+)-activated ATPase and retards the germination of the cress Lepidium sativum. Germicidin is the first known autoregulative inhibitor of spore germination in the genus Streptomyces and was isolated from the supernatant of germinated spores, but also from the supernatant of the submerged culture. Spectroscopic analysis and derivatization reactions revealed germicidin to be 6-(2-butyl)-3-ethyl-4-hydroxy-2-pyrone (C11H16O3). Crude isolates of germicidin from the supernatant of submerged culture, but not from the spores, contained a second, structurally very similar compound (C10H14O3), in which in contrast to germicidin a 2-propyl instead of the 2-butyl chain was bound to C-6 and which did not show any activity in the germination and ATPase assay. The germination assay was evaluated as a new screening model for specifically active compounds.

Long-term ambient concentrations of total suspended particulates, ozone, and sulfur dioxide and respiratory symptoms in a nonsmoking population

Seventh-day Adventist nonsmokers, who, subsequent to 1966, had resided within 8 km (5 miles) of their 1977 residence (N = 3,914), completed the National Heart and Lung Institute (NHLI) respiratory symptoms questionnaire in 1977 and again in 1987. For each participant, cumulative ambient concentrations of total suspended particulates (TSP), ozone, and sulfur dioxide (SO2) in excess of several cutoff levels were estimated by month and by interpolating ambient concentrations from state air-monitoring stations to their residential and workplace zip codes for the month. Statistically significant relationships between ambient concentrations of TSP and ozone, but not SO2, were found with several respiratory disease outcomes. Multivariate analyses adjusted for past and passive smoking and occupational exposures. Results are discussed within the context of standards setting for TSP and ozone.

Autologous versus allogeneic bone marrow transplantation for non-Hodgkin's lymphoma: a case-controlled analysis of the European Bone Marrow Transplant Group Registry data

PURPOSE

A case-controlled study of patients who reported to the European Bone Marrow Transplant Group (EBMTG) was performed to investigate the relative roles and efficacy of allogeneic (alloBMT) and autologous bone marrow transplantation (ABMT) in non-Hodgkin's lymphoma.

PATIENTS AND METHODS

Of 1,060 patients who reported to the lymphoma registry, 938 patients underwent ABMT and 122 patients underwent alloBMT. A case-controlled study was performed by matching 101 alloBMT patients with 101 ABMT patients. The case matching was performed after the selection of the main prognostic factors for progression-free survival by a multivariate analysis.

RESULTS

The progression-free survival was similar in both types of transplants (49% alloBMT v 46% ABMT). The overall relapse and progression rate for the alloBMT patients was 23% compared with 38% in the ABMT patients. This difference was not significant statistically. In the lymphoblastic lymphoma subgroup, alloBMT was associated with a lower relapse rate than ABMT (24% alloBMT v 48% ABMT; P = .035). The progression-free survival, however, was not significantly different because patients with lymphoblastic lymphoma who underwent alloBMT had a higher procedure-related mortality (24% alloBMT v 10% ABMT; P = .06). A significantly lower relapse/progression rate was also observed in patients with chronic graft-versus-host disease (cGVHD) compared with those patients without (0% cGVHD v 35% no cGVHD; P = .02). Fourteen of 18 patients who had cGVHD also had lymphoblastic lymphoma.

CONCLUSION

This study suggests that ABMT and alloBMT for non-Hodgkin's lymphoma are comparable, with the exception of lymphoblastic lymphoma in which a graft-versus-lymphoma effect may account for the lower relapse rate for patients who underwent alloBMT.

Recombinant tumor necrosis factor-alpha potentiates neutrophil degranulation in response to host defense cytokines neutrophil-activating peptide 2 and IL-8 by modulating intracellular cyclic AMP levels

The neutrophil-activating peptide 2 (NAP-2) and IL-8 are closely related in structure and function. In order to further determine their potential biologic roles in inflammation, we studied their interaction with TNF-alpha-primed human polymorphonuclear neutrophil granulocytes at the levels of effector functions and signal transduction. After short term priming (5 min) by TNF-alpha, suspended cytochalasin B-treated PMN responded to NAP-2 or rIL-8 by substantial augmentation of the degranulation response. After priming with 3 ng/ml TNF-alpha marker release from both azurophilic and specific granules was near maximum. NAP-2 and rIL-8 cooperated with TNF-alpha in very similar ways, as indicated by the almost identical increases in release rates that were induced by equipotent doses of either secondary stimulus. At the signal transduction level, pharmacologic elevation of intracellular cAMP led to the inhibition of NAP-2- or rIL-8-induced degranulation in primed and unprimed PMN, indicating a role for this second messenger as a negative feedback signal. Direct measurement of intracellular cAMP revealed that TNF-alpha by itself did not affect its levels. Instead, TNF-alpha reduced both the scale as well as the duration of the cAMP burst generated in response to secondary stimuli NAP-2 or rIL-8. Thus, there is evidence that TNF-alpha priming of neutrophils for enhanced NAP-2- or rIL-8-promoted degranulation involves the antagonistic down-modulation of stimulus-induced rises in cAMP.

Recombinant tumor necrosis factor-alpha potentiates neutrophil degranulation in response to host defense cytokines neutrophil-activating peptide 2 and IL-8 by modulating intracellular cyclic AMP levels

The neutrophil-activating peptide 2 (NAP-2) and IL-8 are closely related in structure and function. In order to further determine their potential biologic roles in inflammation, we studied their interaction with TNF-alpha-primed human polymorphonuclear neutrophil granulocytes at the levels of effector functions and signal transduction. After short term priming (5 min) by TNF-alpha, suspended cytochalasin B-treated PMN responded to NAP-2 or rIL-8 by substantial augmentation of the degranulation response. After priming with 3 ng/ml TNF-alpha marker release from both azurophilic and specific granules was near maximum. NAP-2 and rIL-8 cooperated with TNF-alpha in very similar ways, as indicated by the almost identical increases in release rates that were induced by equipotent doses of either secondary stimulus. At the signal transduction level, pharmacologic elevation of intracellular cAMP led to the inhibition of NAP-2- or rIL-8-induced degranulation in primed and unprimed PMN, indicating a role for this second messenger as a negative feedback signal. Direct measurement of intracellular cAMP revealed that TNF-alpha by itself did not affect its levels. Instead, TNF-alpha reduced both the scale as well as the duration of the cAMP burst generated in response to secondary stimuli NAP-2 or rIL-8. Thus, there is evidence that TNF-alpha priming of neutrophils for enhanced NAP-2- or rIL-8-promoted degranulation involves the antagonistic down-modulation of stimulus-induced rises in cAMP.