Microbial modification of pradimicins at C-11 leading to 11-O-demethyl- and 11-O-L-xylosylpradimicins A and FA-1

In a screen of pradimicin-nonproducing mutants derived from Actinomadura verrucosospora subsp. neohibisca R103-3, we found a strain capable of producing 11-hydroxyl analogs of pradimicins A and FA-1, designated pradimicins H and FH, respectively. Feeding of pradimicins H and FH to growing cultures of an actinomycete strain AA3798 produced 11-O-L-xylosylpradimicins H and FH, respectively. These 11-O-L-xylosylpradimicins had a broad spectrum of antifungal activity and demonstrated in vivo efficacies against Candida albicans in mice.

Assessment of left ventricular diastolic function and potential by quantitative analysis of left ventricular filling curves in patients with atrial fibrillation. A new algorithm for Doppler echocardiographic study

To evaluate left ventricular (LV) diastolic function and potential, LV filling curves for 18 patients with atrial fibrillation (Af) were constructed and their positions and appearance were evaluated quantitatively by analysis of 95% maximal filling volume points and maximal curvature alteration points. The LV filling curves of group A (Af only) lay left superiorly, while those of group B (impaired LV diastolic function) were situated right inferiorly, all bending steeply. The LV filling curves of group C (mitral stenosis) bent slightly. The lowest normal filling volume points and compensation areas were calculated to evaluate LV diastolic function and were demonstrated to be very different in groups A and B. The lowest normal filling volume points of group C were similar to those of group A, but compensation areas were smaller, indicating a lower LV diastolic potential. It is concluded that the 95% maximal filling volume point, maximal curvature alteration point, lowest normal filling volume point and compensation area are effective indices for evaluating not only LV diastolic function but also the diastolic potential.

Synthesis and antifungal activity of pradimicin derivatives. Modifications on the aglycone part

Synthesis and antifungal activity of pradimicin analogs modified on the aglycone part is described. Upon modification studies at various sites of the aglycone part using pradimicin A (PRM A), C-11 position was found to be the sole site to be modified without loosing antifungal activity. Further modification studies at C-11 position were carried out with 11-OH derivative of pradimicin T1 (PRM T1) because of its easy availability. Among the compounds prepared, 11-demethoxy derivative of PRM A (12) and 11-O-ethyl (13) and 11-O-fluoroethyl (14) derivatives of PRM T1 showed promising antifungal activity comparable to that of PRM A.

Antifungal activities of pradimicin derivatives modified at C4'-amino group

In order to explore potent derivatives of pradimicins (PRMs), modification of their C4'-amino group was carried out. 4'-N-Cyano (1,2), 4'-deamino-4'-nitroguanidino (4), 4'-deamino-4'-ureido (7-9) and 4'-deamino-4'-thioureido (10) derivatives were synthesized by trimethylsilylation of PRMs A and C, followed by condensation with appropriate reagents. 4'-Deamino-4'-guanidino (5) and 4'-deamino-4'-amidino (6) derivatives were synthesized by catalytic hydrogenation of 4 and 2, respectively. 4'-N-Nitroso derivative 3 was prepared by treatment of PRM A with nitrous acid. Among these compounds, the 4'-N-cyano derivative of PRM C (2) exhibited in vitro and in vivo antifungal activities comparable to the parent compounds together with good water-solubility.

BU-4794F, a new beta-1,3-glucan synthase inhibitor

New beta-1,3-glucan synthase inhibitor (BU-4794F) was isolated from the culture broth of Gilmaniella sp. FA4459. Structural studies indicated that it was a novel member of the papulacandin group of antibiotics.

Lagunamycin, a novel 5-lipoxygenase inhibitor. I. Taxonomy, fermentation, physico-chemical properties and biological characteristics

Lagunamycin, a novel 5-lipoxygenase inhibitor, was isolated from the culture broth of Streptomyces sp. AA0310. This compound showed potent rat 5-lipoxygenase inhibitory activity (IC50 6.08 microM) without lipid peroxidation.

Verucopeptin, a new antitumor antibiotic active against B16 melanoma. II. Structure determination

The structure of a new antibiotic verucopeptin has been determined by the spectroscopic analyses and chemical degradation studies. It is a 19-membered cyclodepsipeptide which is structurally related to azinothricin and A83586C.

A new neuritogenetic compound BU-4514N produced by Microtetraspora sp

A novel neuritogenetic compound BU-4514N was isolated from the fermentation broth of Microtetraspora sp. T689-92. It showed significant NGF-mimic activity and antibacterial activity against Gram-positive bacteria. Structural studies revealed that BU-4514N was a new chemotype antibiotic related to lydicamycin.

Verucopeptin, a new antitumor antibiotic active against B16 melanoma. I. Taxonomy, production, isolation, physico-chemical properties and biological activity

A new antitumor antibiotic verucopeptin was isolated from the culture broth of Actinomadura verrucosospora Q886-2. It should potent cytotoxicity and specific in vivo activity against B16 melanoma. Maximum T/C value (162%) was obtained by Q1D x 1 treatment schedule.

Morphological changes of Candida albicans induced by BMY-28864, a highly water-soluble pradimicin derivative

The time course of BMY-28864-dependent morphological changes in Candida albicans A9540 was studied by electron microscopy. Scanning electron microscopy revealed that BMY-28864 often induced cell surface deformations such as abnormal swelling and bulging around budding sites and bud scars. The cell membrane damage was visualized by freeze-fracturing technique as deep pit-like invaginations. Transmission electron microscopy with thin-sectioned specimens also demonstrated that BMY-28864 induced cell membrane invaginations together with cell membrane detachment from the cell wall, nuclear membrane fragmentation and mitochondrial aberration. Statistical sequence analysis of the prominent BMY-28864-dependent morphological changes of the yeast cells led to the conclusion that BMY-28864 first attacked the cell membrane and then caused disintegration of other intracytoplasmic organelles, resulting in the lethal effect.

Genesis of the Austin Flint murmur: relation to mitral inflow and aortic regurgitant flow dynamics

OBJECTIVES

This study was designed to elucidate the genesis of the Austin Flint murmur.

BACKGROUND

The Austin Flint murmur is an apical diastolic rumble associated with significant aortic regurgitation. The precise mechanism of the murmur remains unclear.

METHODS

The relation between the Austin Flint murmur and mitral inflow and aortic regurgitant flow dynamics was evaluated nonivasively in 13 patients with moderate to severe aortic regurgitation and 15 control subjects using phonocardiographic and pulsed and color-coded Doppler echocardiographic techniques. The severity of aortic regurgitation was determined by color-coded Doppler echocardiography on the basis of the maximal distance of the regurgitant signal.

RESULTS

The direction of aortic regurgitant flow was unrelated to the presence of the Austin Flint murmur. The severity of aortic regurgitation was greater in patients with than in those without this murmur. The peak mitral inflow velocity during early diastole (E) was significantly increased, and both peak mitral inflow velocity at atrial contraction (A) and the A/E ratio were significantly decreased in patients with the Austin Flint murmur compared with values in those without this murmur or in control subjects. However, the maximal amplitude of the Austin Flint murmur did not coincide temporally with the peak mitral inflow velocity. The murmur continued both after rapid mitral inflow had ended and during diastolic mitral regurgitation.

CONCLUSIONS

The increased velocity of early diastolic mitral inflow in patients with the Austin Flint murmur is due to aortic regurgitation, but rapid mitral inflow is not an essential requirement for production of the murmur. In some cases, the Austin Flint murmur may be generated by aortic regurgitant flow alone.

5-Hydroxyanthranilic acid derivatives as potent 5-lipoxygenase inhibitors

Three new 5-lipoxygenase inhibitors, designated as BU-4601 A, B and C, were found in the fermentation broth of Streptomyces sp. strain No. AA2807. Their structures were identified as isodecyl, isoundecyl and isolauryl esters of 5-hydroxyanthranilic acid, respectively. Based on their structures, five related esters were synthesized and evaluated for biological activity as inhibitors of 5-lipoxygenase. Both naturally-occurring and chemically-synthesized compounds exhibited almost equal levels of 5-lipoxygenase inhibitory activities in vitro.

[One family having 5 members with hypertrophic cardiomyopathy with similar pattern of left ventricular inflow and distribution of hypertrophy]

We examined, in one family, 5 cases of hypertrophic cardiomyopathy (HCM) with a similar pattern of left ventricular inflow (LVIF) and distribution of hypertrophy. Its clinical background and significance were discussed. Because a variety of morphologic expressions of HCM may be observed in the same family, distribution of left ventricular hypertrophy (LVH) varies in even first-degree relatives of the family. In all five cases in this study, however, LVH was localized between the anterior wall and the interventricular septum. On the other hand, typical pattern of LVIF in HCM is "decreased peak velocity and prolonged deceleration time of the early diastolic wave (E), and compensatory augmentation of the atrial contraction wave (A)". All of the five cases in this study had a pattern of three characteristic peaks of LVIF, which showed the mid-diastolic wave between the E and A waves. The above findings suggested that the myocardial characteristics of the five cases in this family were very similar, and could be important clues clarifying the mode of inheritance of HCM.

Pradimicins T1 and T2, new antifungal antibiotics produced by an actinomycete. I. Taxonomy, production, isolation, physico-chemical and biological properties

Pradimicins T1 and T2, new members of the pradimicin family of antibiotics, were produced by an actinomycete strain AA3798. Pradimicin T1 exhibited potent activity against a wide spectrum of fungi in vitro and demonstrated efficacy against systemic Candida albicans and Aspergillus fumigatus infections in mice.

Pradimicins T1 and T2, new antifungal antibiotics produced by an actinomycete. II. Structures and biosynthesis

Pradimicins T1 and T2 are new members of the pradimicin family of antibiotics produced by an actinomycete strain AA3798. Pradimicins T1 and T2 are dihydrobenzo[a]naphthacenequinones substituted with 3 and 2 sugar moieties, respectively. The salient feature in their structures is an L-xylose attached to the phenolic hydroxyl group at C-11. Bioconversion experiments using a blocked mutant B-54 of strain AA3798 not only explored a plausible biosynthetic pathway of pradimicins T1 and T2, but also provided evidence of 5S,6S configuration.

Synthesis and antifungal activity of pradimicin derivatives. Modifications of the sugar part

Modifications at the sugar part of pradimicins were carried out by glycosidations of the aglycones or chemical transformations of natural pradimicins and their antifungal activity was evaluated. Among them, some of the D-xylose-modified derivatives (14, 17, 24) showed activity comparable to that of pradimicin A. The structure-activity relationships obtained through there studies clarified the role of the sugar part in the manifestation of antifungal activity: The 5-O-(6-deoxy-beta-D-sugar) is essential for activity and 2'-epi, 3'-oxo and 4'-deoxy sugar derivatives retain activity against yeasts.

Assessment of obesity of children with spina bifida

Percentage body fat of 35 children with spina bifida and 129 age-matched normal children was measured by underwater weighing and skinfold thickness to assess obesity. Percentage body fat of patients below five years was similar to that of controls; however, 58 per cent of patients above six years had an increased percentage of body fat. The neurological level and ambulatory ability were associated with percentage body fat. A significant correlation between percentage body fat and hydrocephalus suggests that the metabolic and nutritional maladaptation is caused not only by these patients' physical inactivity but also by the condition itself. Appropriate nutritional and mobility programmes should be started early to prevent the development of obesity.

Pradimicin S, a new pradimicin analog. I. Taxonomy, fermentation and biological activities

A directed search for antibiotics active in a syncytium formation inhibition assay using a co-culture of HeLa-T4 cells expressing CD4 antigen and BSC-1 cells expressing gp-120 led to the isolation of pradimicin S, a new member of the pradimicin family. The producing strain (AA0851) was characterized as a new species of Actinomadura for which the name Actinomadura spinosa sp. nov. is proposed. Production of pradimicin S by strain AA0851 was significantly improved by addition of ferrous sulfate (0.1-0.4%) to the production medium. Pradimicin S showed potent activity against human immunodeficiency virus (HIV) LAVBRU strain in a CPE assay, and moderate activity against influenza virus type A. The antibiotic was active against a wide variety of fungi and yeasts in vitro and demonstrated in vivo efficacy against a systemic Candida albicans infection in mice.

A sero-epidemiological study on mother-to-child transmission of HTLV-I in southern Kyushu, Japan

In vertical transmission of HTLV-I the duration of breast-feeding seems to be an important risk factor. In this study, we made prospective and retrospective surveys on the rate of vertical transmission of HTLV-I in infants and their siblings born to HTLV-I seropositive mothers. The results obtained were as follows. (1) In the prospective study, 885 of the 16,283 pregnant women examined were HTLV-I seropositive, and the seropositive rate was 5.4%. The seroconversion rates of short-term (< 7 months) and long-term (> or = 7 months) breast-feeders were 3.8% (1/26 cases) and 25.0% (1/4 cases) respectively, and the rate of bottle-feeders was 5.6% (10/177 cases). Short-term breast-feeding tended to yield a lower seroconversion rate of infants. In addition, the seroconversion rate of short-term breast-feeders was nearly equal to that of bottle-feeders: 3.8% vs. 5.6%. (2) In the retrospective study, the seroconversion rates of short-term and long-term breast-feeders in their siblings were 4.5% (3/67 cases) and 14.0% (19/136 cases) respectively. There was a significant difference between the 2 groups (p < 0.01). Thus, the results of our retrospective and prospective studies suggest that short-term breast-feeding might lessen the risk of breast-milk-borne transmission of HTLV-I from carrier mothers to their children.

Biosynthesis of the pradimicin family of antibiotics. I. Generation and selection of pradimicin-nonproducing mutants

Germinated spores of Actinomadura verrucosospora subsp. neohibisca E-40, a high pradimicins producer, were mutagenized by N-methyl-N'-nitro-N-nitrosoguanidine and/or UV treatment. Thirty-seven mutants which did not produce pradimicin were selected to test for cosynthesis ability, and classified into nine classes. On the basis of their cosynthesis ability and bioconversion results, we concluded that strain JN-213 (class III) was a true converter and that strains JN-219 (class IV), JN-47 (class V) and JNU-46 (class VI) were secretors accumulating biosynthetic intermediates of pradimicin, and that strains JN-59 (class VII), JN-58 (class VIII) and JN-207 (class IX) were producers of shunt metabolites of pradimicin biosynthesis. TLC and HPLC analyses of the fermentation broths of individual strains showed that 8 new compounds were produced along with pradinone I, pradimicinone I, 11-O-demethylpradimicinone II and 7-O-methylpradimicinone II.

Pradimicin S, a new pradimicin analog. II. Isolation and structure elucidation

Pradimicin S was isolated from the culture filtrate of Actinomadura spinosa AA0851. NMR and MS analyses proved that pradimicin S is the 3'-O-(3''-O-sulfo-beta-D-glucopyranosyl) analog of pradimicin A, a new member of the pradimicin family of antibiotics. Stereochemical assignment was made by correlating pradimicin S with pradimicin L.

Synthesis and antifungal activities of alanine-exchanged analogs of pradimicin A

A series of pradimicin analogs were designed and synthesized to investigate the effect of the amino acid side chain on the antifungal activity. The alanine-exchanged analogs (3a approximately 3q) were synthesized from 4'-N-Cbz-pradimic acid by coupling with appropriate amino acids or their equivalents followed by deblocking. All the D-alpha-amino acid derivatives except D-proline analog, 3k retained the antifungal activity.

Biosynthesis of the pradimicin family of antibiotics. II. Fermentation, isolation and structure determination of metabolites associated with the pradimicins biosynthesis

Ten metabolites produced by 4 mutants derived from Actinomadura verrucosospora subsp. neohibisca E-40, a high pradimicins producer, were isolated and their structures were determined. Strain JN-219 produced 3 novel analogs of the pradimicin A aglycone, i.e. 11-O-demethyl-7-methoxypradinone II and 11-O-demethylpradinones I and II together with a known aglycone analog, pradinone I, while the metabolites from strain JN-47 were determined to be 2 new aglycone analogs, 11-O-demethylpradimicinone I and 11-O-demethyl-7-methoxypradimicinone II and a known aglycone analog, 11-O-demethylpradimicinone II (11dM-PMN II). Products of strain JN-207 were identified as 11-O-demethyl-6-deoxypradinone I and 11dM-PMN II. Interestingly, a new pradimicin analog, 7-hydroxypradimicin A was isolated from strain JN-58 together with a new aglycone analog, pradimicinone II and 11dM-PMN II. None of these metabolites showed antifungal activity.

Synthesis and antifungal activities of pradimicin A derivatives modification of the alanine moiety

Chemical modifications of the carboxyl group in the alanine moiety of pradimicin A were performed and in vitro and in vivo antifungal activities of the derivatives were examined in comparison with those of pradimicin A. The amide derivatives showed activities comparable to pradimicin A, indicating that the free carboxyl group can be modified without impairing the antifungal activity.

Pradimicins L and FL: new pradimicin congeners from Actinomadura verrucosospora subsp. neohibisca

Pradimicin L, a new congener of pradimicin A having the D-glucosyl-D-thomosamine moiety at the C-5 position, was isolated from Actinomadura verrucosospora subsp. neohibisca subsp. nov. The structure of pradimicin L was deduced to be N-[[(5S,6S)-5-O-[4,6-dideoxy-4-(methylamino)-3-O-(beta-D-glucopyranosyl) - beta-D-galactopyranosyl]-5,6,8,13-tetrahydro-1,5,6,9,14-pentahydroxy-11- methoxy-3-methyl-8,13-dioxobenzo[a]naphthacene-2-yl]carbonyl ]-D-alanine by MS and NMR spectrometry and degradation studies. Pradimicin FL which has the D-serine moiety instead of D-alanine was produced by directed biosynthesis in D-serine-supplemented medium. Pradimicins L and FL have a broad spectrum of in vitro antifungal activity. Pradimicin L was equiactive to pradimicin A and pradimicin FL was more active than pradimicin L.

Biosynthesis of the pradimicin family of antibiotics. III. Biosynthetic pathway of both pradimicins and benanomicins

The biosynthetic pathway of the pradimicin-benanomicin family of antibiotics was investigated by using sinefungin and blocked mutants derived from Actinomadura verrucosospora subsp. neohibisca E-40 (a high pradimicin producer) or Actinomadura sp. AB1236 (a benanomicin producer). Addition of sinefungin to strain E-40, pradimicin A aglycone-producing mutant or strain AB1236 inhibited the formation of 11-O-demethyl-7-methoxypradinone II (11dM-7M-PN II), resulting in the accumulation of 11-O-demethylpradimicinone II and pradimicinone II. By feeding pradimicin A aglycone and its analogs to mutants blocked early in pradimicin or benanomicin biosynthesis, the following results were obtained: 11-O-demethylpradinone II, 11dM-7M-PN II 11-O-demethylpradinone I, 11-O-demethylpradimicinone I and pradimicinone I were converted to pradimicin A or benanomicin A; the remaining 6 aglycone analogs were not incorporated into the antibiotics. Pradimicin B, dexylosylpradimicin C and dexylosylbenanomicin A were converted to pradimicin A, pradimicin C and benanomicin A, respectively. A biosynthetic pathway for the antibiotics is proposed.

Studies on the mode of antifungal action of pradimicin antibiotics. II. D-mannopyranoside-binding site and calcium-binding site

Based on the structure-activity relationship data of BMY-28864 and related pradimicin derivatives, the calcium salt-forming ability and the D-mannopyranoside-specific visible absorption maximum shift of BMY-28864 were analysed in the ternary complex formation of BMY-28864 with D-mannopyranoside and calcium. The free C-18 carboxyl group of BMY-28864 was proved to be the sole site for binding to calcium, while no hydroxyl groups of the aglycone were involved in calcium salt formation. The stereospecific D-mannopyranoside-recognizing ability of BMY-28864 was completely abolished by removal of the C-5 disaccharide moiety, and, more particularly, of the C-5 thomosamine moiety. Close relationship of these findings with the antifungal action was also supported by the in vitro antifungal assay and the potassium leakage induction test.

Pradimicins FS and FB, new pradimicin analogs: directed production, structures and biological activities

Exogenous addition of D-serine to Actinomadura spinosa AA0851 resulted in directed production of pradimicin FS, a new D-serine analog of pradimicin S, together with pradimicin FB. Pradimicin FS was produced in higher yields by derivation of ferrous sulfate-resistant strains from strain AA0851. Pradimicin FB, a minor product, was identified as deglucosylpradimicin FL. Pradimicin FS was equivalent to pradimicin S in syncytium formation inhibition activity and in vitro and in vivo antifungal activities.

Studies on the mode of antifungal action of pradimicin antibiotics. III. Spectrophotometric sequence analysis of the ternary complex formation of BMY-28864 with D-mannopyranoside and calcium

Sequence of reactions in the process of ternary complex formation of BMY-28864 with D-mannopyranoside and calcium was spectrophotometrically determined under more strict analytical conditions using metal-free preparations of sugars and the pradimicin derivative at a bandpass slit width of 1 nm. In the first phase of ternary complex formation, BMY-28864 stereospecifically recognized and bound to D-mannopyranoside in the absence of calcium, which was revealed by a visible absorption maximum shift of ca. 8 nm. Subsequently, the BMY-28864-D-mannopyranoside conjugate reacted with calcium to yield the ternary complex, which was detected by an additional visible absorption maximum shift of ca. 8 nm. When the three components were mixed at the same time, both phases simultaneously occurred to produce the ternary complex which was accompanied by a visible absorption maximum shift of 16 nm in total. Based on this two-phased reaction sequence, the mechanism of ternary complex formation of BMY-28864 with D-mannopyranoside and calcium was reexamined in details. Terminal D-mannopyranoside was confirmed to be essential as BMY-28864-specific sugar receptor by in vitro analysis and animal cell experiments. While calcium, strontium and cadmium behaved similar in the in vitro ternary complex formation, the yeast and animal cell experiments showed that only calcium played a dual role as a base in the ternary complex formation and as an effector in physiological disturbances leading to cell death.

BMS-181184, a new pradimicin derivative. Screening, taxonomy, directed biosynthesis, isolation and characterization

BMS-181184 is a new semisynthetic pradimicin derivative with a broad-spectrum antifungal activity. In a search for actinomycetes producing BMS-181184, 4 strains of Actinomadura sp. isolated from soil samples were found to produce the antibiotic under conditions of directed biosynthesis. Among them, Actinomadura sp. AB1236 proved most useful in the production of BMS-181184 when fermented in a medium containing D-serine and D-cycloserine. A minor product isolated from the broth of strain AB1236 was identified as the dexylosyl analog of BMS-181184, which was also obtained by acid hydrolysis of BMS-181184.

Studies on the mode of antifungal action of pradimicin antibiotics. I. Lectin-mimic binding of BMY-28864 to yeast mannan in the presence of calcium

BMY-28864 (BMS-181184), a water-soluble pradimicin derivative, specifically bound on the yeast cell surface in the presence of calcium, which was considered to be the initial step that triggered chain reactions leading to the fungicidal action. Close cause-effect relationships of the cell wall binding of BMY-28864 with its antifungal activity and potassium leakage induction were observed by Candida albicans and Saccharomyces cerevisiae in the presence and absence of calcium. Using mannan and methyl alpha-D-mannopyranoside as specific sugars, the mode of binding of BMY-28864 to sugar was examined in vitro in the presence of calcium. Quantitative component analysis revealed that the precipitate of BMY-28864 with methyl alpha-D-mannopyranoside and calcium was a ternary complex possessing a molar component ratio of 2.1:4.3:1.0. These findings altogether proved that BMY-28864, although not protein, recognized specific sugars such as mannose in the same manner as lectin, and that the ternary complex formation of BMY-28864 with specific sugar and calcium was the first step for expression of the selective antifungal action of the pradimicin.

Characterization of a cloned rat serotonin 5-HT1A receptor expressed in the HeLa cell line

We have previously isolated the rat serotonin (5-HT)1A receptor gene (G21Y2) and now report the expression and characterization of this receptor. The BamHI/Xbal fragment of this gene was cloned into Rc/RSV and stably transfected into HeLa cells by the calcium phosphate method. For determination of specific 5-HT1A receptor binding, [3H]8OH-DPAT was used as the radioligand and incubated with HeLa cell membranes. The cells expressed specific and saturable binding of [3H]8OH-DPAT with a Kd value of 0.3 nM and a Bmax value of 2 pmol/mg protein. GTP (50 microM) added to the incubation mixture increased the Kd value to 3 nM indicating that the expressed receptor is coupled to a G protein. The specific binding was inhibited by selective 5-HT1A partial agonists, such as buspirone, ipsapirone, gepirone, tandospirone, zalospirone and SUN8399 with Ki values of 1-30nM, whereas other neurotropic drugs except for spiperone (Ki = 46 nM) and nemonapride (Ki = 2.3 nM) were effective only at concentrations of more than 100 microM. The potencies of these compounds to inhibit [3H]8OH-DPAT from its specific binding sites were similar to their affinities determined in rat hippocampus binding studies. These data suggest that the expressed receptor is a 5-HT1A-type similar to 5-HT1A receptors in the rat hippocampus.

Epocarbazolins A and B, novel 5-lipoxygenase inhibitors. Taxonomy, fermentation, isolation, structures and biological activities

New 5-lipoxygenase inhibitors, designated epocarbazolins A and B, were isolated from the culture broth of Streptomyces anulatus T688-8. These compounds showed potent rat 5-lipoxygenase inhibitory activity with weak antibacterial activity. Structural studies revealed that epocarbazolins are new carbazole antibiotics having a novel substitution pattern and an epoxide in the side chain.

Protective effect of eurystatins A and B, new prolyl endopeptidase inhibitors, on scopolamine-induced amnesia in rats

Eurystatins A and B, which are produced by Streptomyces eurythermus R353-21, potently inhibited Flavobacterium prolyl endopeptidase (PED) with IC50 values of 0.004 and 0.002 micrograms/ml, respectively, while no inhibition was observed against another 5 proteases, even at 100 micrograms/ml. The protective effect of eurystatins A and B against scopolamine (3 mg/kg, i.p.)-induced amnesia in rats was evaluated by the step-through one-trial passive avoidance method. When administered i.p. 30 min prior to the acquisition trial, both eurystatins A, at 2-8 mg/kg, and B, at 4-8 mg/kg, significantly protected rats from the amnesic effect of scopolamine without behavioral side effects.

Epoxomicin, a new antitumor agent of microbial origin

An actinomycete strain No. Q996-17 produced a novel compound, epoxomicin, which exhibited in vivo antitumor activity against B16 melanoma. Structural studies indicated that it is a new member of the epoxy-beta-aminoketone group, and is closely related to eponemycin.

Eurystatins A and B, new prolyl endopeptidase inhibitors. I. Taxonomy, production, isolation and biological activities

Eurystatins A and B, were isolated from the cultured broth of Streptomyces eurythermus R353-21. They showed specific and potent inhibitory activity against prolyl endopeptidase and did not show antimicrobial activity. No lethal toxicity was observed for the two compounds after ip administration in mice at 200 mg/kg.

New antiviral antibiotics, cycloviracins B1 and B2. II. Structure determination

The structures of novel antiviral antibiotics, cycloviracins B1 and B2 have been determined by means of chemical and spectroscopic methods including 2D NMR correlation spectroscopy. The antibiotics are unique macrocyclic diesters consisting of two D-glucoses, three 2-O-methyl-D-glucoses and two (C24 and C26) hydroxy fatty acids.

Synthesis and antifungal activities of pradimicin derivatives, modification at C4'-position

The 4'-N-alkyl(1 approximately 10) and 4'-N-acyl derivatives (11 approximately 21) of pradimicins (PRMs) were synthesized by trimethylsilylation of PRMs A, C and FA-1 followed by condensation with appropriate alkylating and acylating agents. The 4'-hydroxy derivatives (23 and 24) were synthesized from PRM FA-2 in a 3-step sequence. Among these compounds, the 4'-N-carboxyl substituted alkyl (1, 5, 8 and 10), 4'-N-formyl (11) and 4'-axial-hydroxy (23) derivatives retained the antifungal activity of the parent compounds and showed great improvement in water solubility.

Lactimidomycin, a new glutarimide group antibiotic. Production, isolation, structure and biological activity

Streptomyces amphibiosporus R310-104 (ATCC 53964) produced a novel antibiotic lactimidomycin which showed inhibitory activity against fungi and prolonged the survival time of mice transplanted with experimental tumors. Structural studies clarified that lactimidomycin is a new glutarimide antibiotic having a unique unsaturated 12-membered lactone ring.

New antiviral antibiotics, cycloviracins B1 and B2. I. Production, isolation, physico-chemical properties and biological activity

Kibdelosporangium albatum No. R761-7 (ATCC 55061) produced new antiviral antibiotics, cycloviracins B1 and B2. They show weak activity against Gram-positive bacteria and potent antiviral activity against herpes simplex virus type 1. Unique acylsaccharide structures were established for cycloviracins B1 and B2 by degradation and spectroscopic analysis.

Butyrolactols A and B, new antifungal antibiotics. Taxonomy, isolation, physico-chemical properties, structure and biological activity

New antifungal antibiotics, butyrolactols A and B, have been isolated from the culture broth of Streptomyces rochei S785-16. They are novel type of molecules containing a common 2,3-dihydroxybutyrolactone nucleus substituted with a different long hydroxyalkyl side chain. Butyrolactol A showed good antifungal activity against Aspergillus fumigatus and Trichophyton mentagrophytes, and moderately inhibited the growth of yeasts.