Dereplication of Streptomyces soil isolates and detection of specific biosynthetic genes using an automated ribotyping instrument

The discrimination of distinct cultures among morphologically similar Streptomyces soil isolates (dereplication) and the detection of specific biosynthetic pathways in these strains are important steps in the selection of microorganisms to include in a natural products library. We have developed methods for analysis of actinomycetes using the RiboPrinter microbial characterization system, an automated instrument that performs ribotyping on bacterial samples. To evaluate our dereplication method, 26 Streptomyces isolates, obtained from soil samples collected in Maui, Hawaii, were ribotyped and compared with each other, using the RiboPrinter. The strains were also compared by 16S rDNA sequence analysis, MIDI fatty acid analysis, and LC-MS profiling of fermentation extracts. The RiboPrinter was able to identify closely related isolates and to discriminate between morphologically similar isolates with unique genetic, fatty acid and fermentation profiles. For the detection of biosynthetic genes, a 1,006-bp probe containing a portion of an adenylation domain of a non-ribosomal peptide synthetase (NRPS) was employed. Using this alternate probe in place of the standard ribosomal probe, the RiboPrinter was able to detect NRPS genes in several strains of Streptomyces. These results demonstrate that the RiboPrinter has multiple applications in a natural products research program.

Mannopeptimycins, new cyclic glycopeptide antibiotics produced by Streptomyces hygroscopicus LL-AC98: antibacterial and mechanistic activities

Mannopeptimycins alpha, beta, gamma, delta, and epsilon are new cyclic glycopeptide antibiotics produced by Streptomyces hygroscopicus LL-AC98. Mannopeptimycins gamma, delta, and epsilon, which have an isovaleryl substitution at various positions on the terminal mannose of the disaccharide moiety, demonstrated moderate to good antibacterial activities. Mannopeptimycin epsilon was the most active component against methicillin-resistant staphylococci and vancomycin-resistant enterococci (MICs, 2 to 4 micro g/ml for staphylococci and streptococci and 4 to 32 micro g/ml for enterococci), while mannopeptimycins gamma and delta were two- to fourfold less active. Mannopeptimycins alpha and beta, which lack the isovaleryl substitution and the disaccharide moiety, respectively, had poor antibacterial activities. The in vivo efficacies of the mannopeptimycins in Staphylococcus aureus mouse protection studies paralleled their in vitro activities. The median effective doses of mannopeptimycins gamma, delta, and epsilon were 3.8, 2.6, and 0.59 mg/kg of body weight, respectively. The mannopeptimycins were inactive against cell wall-deficient S. aureus and caused spheroplasting of Escherichia coli imp similar to that observed with penicillin G in an osmotically protective medium. Mannopeptimycin delta rapidly inhibited [(3)H]N-acetylglucosamine incorporation into peptidoglycan in Bacillus subtilis and had no effect on DNA, RNA, or protein biosynthesis. On the basis of the observations presented above, an effect on cell wall biosynthesis was suggested as the primary mode of action for mannopeptimycin delta. The mannopeptimycins were inactive against Candida albicans, did not initiate hemolysis of human erythrocytes, and did not promote potassium ion leakage from E. coli imp, suggesting a lack of membrane damage to prokaryotic or eukaryotic cells.

The house that's on fire: meaning-centered psychotherapy pilot group for cancer patients

People with advanced cancer face an existential crisis in addition to their physical suffering. The principles of a new group therapy intervention (MCGP) were introduced in another paper in this issue. This paper is a report of some of the themes and issues that arose during the first pilot group.

Cancer and the experience of meaning: a group psychotherapy program for people with cancer

Cancer illness affects people in many ways, physical, financial, and existential. In this paper, we describe a proposed group intervention for individuals with advanced disease who want help finding a sense of meaning at this critical juncture in their lives. This intervention has a brief, semi-structured format, and is informed by the work of Viktor Frankl, empirical findings in the area of meaning and trauma, and the empirical findings of other group interventions for cancer patients. Individual sessions focus on different aspects of meaning, including responsibility to others, creativity, transcendence, and ascertaining one's values and priorities. Having goals on which to focus and feeling like part of a larger whole are critically important to the ability to find meaning and cope with terminal illness. Such goals may be generated by a number of sources, including connectedness with others, or a sense of the temporal continuity of one's own life despite the disruption posed by severe illness. Didactic discussions and experiential exercises help to facilitate exploration of these various elements in group members' lives. The finite structure of the intervention may also highlight these issues, as people who are faced with similar issues work together in a limited time frame in order to accomplish the goals they set out for themselves.

Job satisfaction among certified and non-certified general practitioners

BACKGROUND

The aim of family medicine is to provide patients with comprehensive care within the biopsychosocial model. High job satisfaction is necessary to attract physicians to this specialty.

OBJECTIVE

To compare job satisfaction levels between primary physicians with training in family medicine and physicians without specialty training.

METHODS

A self-report questionnaire, the "Task Profiles of General Practitioners in Europe," was mailed to a stratified random sample of 664 primary care physicians in Israel. The response rate was 77.6%. Bivariate and logistic regression procedures were used to analyze the data.

RESULTS

Physicians with training in family medicine were less satisfied with the rewards for their work than general practitioners with no formal specialization in family medicine. Satisfaction with the intrinsic aspects of the work was found to be equal. Women and rural physicians were more satisfied than men and urban physicians.

CONCLUSION

Measures should be taken by health maintenance organizations to increase the level of job satisfaction of specialist-certified family physicians to avoid a crisis in the profession.

Saccharomicins, novel heptadecaglycoside antibiotics produced by Saccharothrix espanaensis: antibacterial and mechanistic activities

Saccharomicins A and B, two new heptadecaglycoside antibiotics, were isolated from the fermentation broth of the rare actinomycete Saccharothrix espanaensis. They represent a novel class of bactericidal antibiotics that are active both in vitro and in vivo against bacteria and yeast (MICs: Staphylococcus aureus, <0.12 to 0. 5; vancomycin-resistant enterococci, 0.25 to 16; gram-negative bacteria, 0.25 to >128; and yeast, >128 microg/ml), including multiply resistant strains. Saccharomicins protected mice from lethal challenges by staphylococci (subcutaneous 50% effective dose range of 0.06 to 2.6 mg/kg of body weight, depending on the S. aureus strain). The 50% lethal dose by the subcutaneous route was 16 mg/kg. Mechanistic studies with Escherichia coli imp and Bacillus subtilis suggested complete, nonspecific inhibition of DNA, RNA, and protein biosynthesis within 10 min of drug treatment. Microscopic examination of drug-treated cells also suggested cell lysis. These data are consistent with a strong membrane-disruptive activity. The antibacterial activities of the saccharomicins against gram-positive bacteria were unaffected by the presence of Ca(2+) or Mg(2+), but activity against gram-negative bacteria was substantially reduced.

Antibacterial leads from microbial natural products discovery

The accidental discovery of penicillin and the advent of sulfanilamide marked the beginning of the antibiotic era. Although synthetic compounds have continued to play important roles in the fight against bacterial infections, the contribution of microbial natural products cannot be underestimated. A vast majority of the antibacterial agents in clinical use today are either microbial natural products or one of their analogs. Finding novel chemical entities with new modes of action and optimizing their activities Microbial natural products have been a proven, rich source of novel compounds with diverse biological activities. The astounding success of the 'golden' period of the antibiotic era delivered several capable of meeting the needs of that period, and subsequently, a period of diminished commitment to finding new antibiotics was experienced. An interest in microbial natural products for other therapeutic applications continued however, and has proved rewarding. The recent increase in the emergence of antibiotic-resistant bacteria has forced many to shift their attention towards finding novel antibiotics and not surprisingly, microbial natural products are being seriously pursued as a source. New antibiotics are being isolated and the old libraries of under-exploited antibiotics are being re-examined. Novel bacterial targets are being exposed through genomics and microorganisms are being genetically engineered for novel metabolites.

Biological activity of guanacastepene, a novel diterpenoid antibiotic produced by an unidentified fungus CR115

Fermentation extracts of culture CR115, an unknown plant endophyte originally isolated from Costa Rica, were found to be active against antibiotic-resistant bacteria. The metabolite responsible for activity was identified as a novel diterpenoid antibiotic guanacastepene (mol. wt. 374.47 and mol. formula C22H30O5). Mechanistic studies done in an E. coli imp strain suggested membrane damage as the primary mode of bactericidal action. This compound also lysed human RBCs and caused leakage of intracellular potassium from E. coli imp.

Novel polyketide metabolites from a species of marine fungi

Fermentation of a marine fungal species obtained from a tissue sample of a marine sponge collected in Indonesia in October 1996, yielded the novel hexaketide compounds iso-cladospolide B (1); seco-patulolide C (2); the 12-membered macrolides, pandangolide 1 (3) and pandangolide 2 (4); and the known terrestrial fungal metabolite, cladospolide B (5).

Rotary encoding for intravascular ultrasonic imaging systems

Images produced with an intravascular ultrasound system (IVUS) can be distorted because of uncertainty in the instantaneous angular position of a rotating ultrasonic transducer. A rotary encoder placed in proximity to the transducer is required to detect the problem; however, size constraints make a conventional electromechanical or optomechanical encoder difficult to implement. Measurements that test the feasibility of a software-derived encoder, based of the rate of decorrelation of ultrasonic RF lines with angle, are reported. Provided that the instantaneous angular velocity of the transducer can be measured, adjustments can be made to the pulse rate of the transducer, which would eliminate the image distortion.

Biosynthesis of the pyrroindomycins by Streptomyces rugosporus LL-42D005; characterization of nutrient requirements

Streptomyces rugosporus LL-42D005 was shown to produce the novel pyrroindomycin antibiotics. Production of pyrroindomycin (alpha) and chloro-pyrroindomycin (beta) was characterized in a semi-defined fermentation medium containing glucose, casein, phosphate, vitamins and minerals. Accumulation of pyrroindomycin beta increased with increasing concentrations of glucose, reaching maximum titers at approximately 5g/L glucose. Glucose concentrations greater than 7.5 g/L decreased pyrroindomycin beta yields. Inhibition of pyrroindomycin accumulation at higher glucose concentrations could be reversed by increasing the casein concentration. Ammonium chloride, arginine or glutamine could replace casein as the sole nitrogen source for growth and pyrroindomycin production. Glucose, fructose or mannitol were utilized as the sole carbon source, while sucrose, maltose, glycerol, corn oil and starch were poorly metabolized. Incubation of this isolate in a vitamin-deficient medium resulted in a delay in growth and pyrroindomycin production; this delay was eliminated by the addition of biotin. Addition of L-tryptophan to the medium resulted in the production of pyrroindomycin alpha as the major species.

Hongoquercins, new antibacterial agents from the fungus LL-23G227: fermentation and biological activity

Two new antibiotics, hongoquercins A and B, were isolated from fermentation extracts of the unidentified fungus LL-23G227. In the optimum medium, titers of the A and B components reached approximately 2.1 g/liter and 0.02 g/liter, respectively. The optimum temperature for antibiotic production was approximately 22 degrees C. Growth was delayed at 15 degrees C but appeared to reach higher levels than was observed at 22 degrees C. Addition of dextrose to growth media increased hongoquercin B production. Hongoquercin A exhibited moderate activity against Gram-positive bacteria. Mechanistic studies conducted in an E. coli imp strain suggested membrane damage as the primary mode of bactericidal action. These compounds also lysed human red blood cells, suggesting a similar mode of action on eukaryotic cells.

[Characteristics of adults with emotional distress in Israel-- patterns of mental health services used]

We sought firsthand data on the extent of perceived mental health needs and on patterns of use of mental health services among Israelis aged 22 and over. The data are from a national survey conducted in 1995. A random sample of phone numbers from the telephone company's computerized listings yielded 1,395 completed questionnaires (response rate, 81%). At some point in their lives, 27% had experienced emotional distress or mental health problems with which they had difficulty coping alone; 13.4% reported that they had such an experience during 1995. According to multivariate analysis, those more likely to report mental health problems were women, those with a chronic disease, Russian immigrants, divorced or widowed adults, those with a low level of education, and members of the Clalit sick fund. 38% of those who had ever had emotional or mental health problems had asked for help. The proportion of those seeking help was high among respondents aged 35-55, Hebrew speakers (compared to speakers of Russian or Arabic), and city dwellers, and the rate was low among members of the Clalit sick fund. Of those who did seek help, 39% went to a psychologist or a psychiatrist, 25% to their family doctor, 19% to a family member or friend, 7% to a social worker or social service agency, 6% to other medical personnel, and 4% to a psychiatric hospital. 30% turned for assistance to the private sector and 70% to the public sector. These findings have special significance in view of the impending reform of the mental health services. As mandated by the new National Health Insurance Law, mental health services are to be included in the basket of health services provided by the sick funds. The data can be of use in the management of sick funds and for physicians working in the community, as they prepare for this change. In addition, the data will be of aid to national policy makers in planning services suited to the needs of different population groups and to allocate resources more rationally.

Cell wall active antifungal compounds produced by the marine fungus hypoxylon oceanicum LL-15G256. I. Taxonomy and fermentation

The cell wall targeted antifungal activity of Hypoxylon oceanicum LL-15G256 extracts resulted from the production of novel lipodepsipeptides and previously reported macrocyclic polylactones. In an optimized medium, titers of the lipodepsipeptide and the polylactones reached approximately 200-400 mg/liter and 25-50 mg/liter, respectively. The optimum fermentation temperature for production of 15G256 gamma was 28 degrees C. Seawater appeared to have an inhibitory effect on metabolite accumulation at lower fermentation temperatures.

Marine microorganisms as a source of new natural products

Over the past decade, marine microorganisms have become recognized as an important and untapped resource for novel bioactive compounds. The oceans cover greater than 70% of the earth's surface and, taking this into account by volume, represent better than 95% of the biosphere. Given this fact, the oceans present themselves as an unexplored area of opportunity for the discovery of pharmacologically active compounds. In this review, data have been presented to illustrate the diversity of microorganisms living in the sea and the plethora of chemical compounds that have been discovered from them. However, it is important to pursue basic research on the marine environment in order to permit the continued isolation of unique microorganisms. There is still limited knowledge of the physiological requirements of most marine microorganisms, and a greater understanding of their conditions for growth will offer new insights into the complex world of marine microbiology. Clearly, a greater investment in the development of marine biotechnology will produce novel compounds that may contribute significantly toward drug development over the next decade.

Isolation, characterization and structure of a new allenic polyine antibiotic produced by fungus LL-07F275

Antibiotic 07F275 (1), produced by submerged fermentations of fungal culture LL-07F275, was isolated and characterized despite its inherent instability. Its UV spectrum was identical with that of nemotin, a member of the allenic polyacetylene family, but a molecular weight of 218 daltons indicated a new compound. Structure 1 was determined on the basis of spectroscopic evidence, particularly NMR. Since 1 is a thirteen carbon-containing allenic diyne, it is closely related to mycomycin.

Martinomycin, a new polyether antibiotic produced by Streptomyces salvialis. I. Taxonomy, fermentation and biological activity

Actinomycete culture LL-D37187 has been found to produce the new polyether antibiotic martinomycin. Taxonomic studies, including morphological, physiological, and cell wall chemistry analyses, revealed that culture LL-D37187 is a novel streptomycete species, and the proposed name is Streptomyces salvialis. Martinomycin exhibits activity against the Southern Army Worm (Spodoptera eridania) and Gram-positive bacteria.

Bioxalomycins, new antibiotics produced by the marine Streptomyces sp. LL-31F508: taxonomy and fermentation

An actinomycete strain designated LL-31F508 was isolated from an intertidal sediment sample collected in Key West, Florida. Culture LL-31F508 was assigned to the Streptomyces genus based on the presence of LL-diaminopimelic acid (DAP) in the cell wall and observations of spiny spores using scanning electron microscopy (SEM). Excellent antimicrobial activity against Staphylococcus and Enterococcus spp. were detected in both the supernatant and cell extract samples from fermentations of culture LL-31F508. Production of antibiotic activity peaked at 48-50 hours and closely paralleled cell growth, during which time glucose was more rapidly assimilated than dextrin. A series of new antibiotics called the bioxalomycins was identified as the antibacterial products from fermentations of this culture. Fermentation conditions for production of bioxalomycin alpha differed substantially from those required for production of a related compound, naphthyridinomycin, by the reference culture Streptomyces lusitanus NRRL 8034.

Pyrroindomycins, novel antibiotics produced by Streptomyces rugosporus LL-42D005. II. Biological activities

The pyrroindomycins, a complex of novel antibiotics identified in fermentation broths of "Streptomyces rugosporus" LL-42D005, demonstrated excellent in vitro activity against Gram-positive bacteria. The semisynthetic diacetyl derivative of pyrroindomycin B (pyrroindomycin B-Ac2) was bactericidal for exponential-phase cells, but not for stationary-phase cells. This compound also exhibited marginal protection against a lethal Staphylococcus aureus challenge in mice. The poor in vivo activity of this antibiotic complex may be related to binding to blood components, as suggested by elevated MICs observed in blood-containing media. Incorporation of radiolabeled precursors into DNA, RNA, and protein was inhibited in an exponential-phase culture of Bacillus subtilis within ten minutes of exposure to pyrroindomycin B-Ac2. Microscopic examinations of drug-treated cells revealed lysis within the same ten minute period. These data are consistent with an effect of pyrroindomycin B-Ac2 on the integrity of the bacterial membrane.

Mechanistic studies and biological activity of bioxalomycin alpha 2, a novel antibiotic produced by Streptomyces viridodiastaticus subsp. "litoralis" LL-31F508

The bioxalomycins, a novel complex of broad-spectrum antibiotics, were isolated from fermentations of Streptomyces viridodiastaticus subsp. "litoralis" LL-31F508. Bioxalomycin alpha 2, the major component of this complex, exhibited antibacterial activity. The MICs ranged from < or = 0.002 to 0.008 micrograms/ml for gram-positive organisms and from 0.50 to 4 micrograms/ml for gram-negative organisms. Bioxalomycin alpha 2 was found to be bactericidal and to inhibit bacterial DNA synthesis preferentially. Bioxalomycin alpha 2 protected mice from a lethal challenge with Staphylococcus aureus Smith. The 50% effective dose of bioxalomycin alpha 2 administered orally was 10 times greater than that when the drug was given subcutaneously or intravenously. These data suggest a stability or bioavailability problem when the compound is administered orally.

Mode of action of the cyclic depsipeptide antibiotic LL-AO341 beta 1 and partial characterization of a Staphylococcus aureus mutant resistant to the antibiotic

The antibacterial activity of the cyclic antibiotic LL-AO341 beta 1 was examined. The antibiotic was a narrow spectrum agent, effective principally against Gram-positive organisms. The intrinsic insusceptibility of Escherichia coli was due to exclusion of the drug by the outer membrane. The antibiotic was bactericidal against Staphylococcus aureus, and cell death was associated with lysis of the bacteria. The antibiotic did not specifically inhibit the synthesis of DNA, RNA, protein, lipid or peptidoglycan since these synthetic activities continued for several minutes after exposure to lethal concentrations of the antibiotic and then all abruptly ceased between about 8 and 15 minutes post antibiotic exposure. These results are consistent with the cytoplasmic membrane being the primary target for LL-AO341 beta 1. Mutants of S. aureus 8325-4 selected on 10- or 20-times the MIC of LL-AO341 beta 1 occurred spontaneously with a frequency of about 3 x 10(-6). A mutant expressing a 160-fold increase in the MIC of LL-AO341 beta 1 was obtained by exposing cultures to progressively increasing concentrations of the antibiotic. This mutant displayed no cross-resistance to other agents apart from telomycin (a structural analogue of LL-AO341 beta 1), apparently did not modify or degrade LL-AO341 beta 1 and had only a slightly longer doubling time than the parent strain.

An assay for the detection of bacterial DNA gyrase inhibitors

In summary, we have developed a sensitive detection system for inhibitors of bacterial DNA gyrase. The use of B. subtilis as the host organism confers the advantage that it is sensitive to both gyrase subunit A and B inhibitors, whereas E. coli is relatively insensitive to B subunit inhibitors in vivo. Using this assay, we identified a new DNA gyrase inhibitor with a novel structure.

A study on the mechanism of action of sceptrin, an antimicrobial agent isolated from the South Pacific sponge Agelas mauritiana

The mechanism of action of sceptrin, an antimicrobial agent isolated from the sponge Agelas mauritiana, was investigated. Sceptrin has been reported to exhibit antibacterial and antifungal activities. In our studies, sceptrin demonstrated a bacteriostatic rather than bactericidal effect on exponentially growing Escherichia coli cells at the MIC. Under these conditions, the culture produced chains of cells, and incorporation of radio-labelled precursors into DNA, protein, and cell wall was unaffected, whereas incorporation of 3H-uridine into RNA was slightly inhibited. At concentrations higher than the MIC, sceptrin was bactericidal, inhibited the incorporation of all radiolabelled precursors, and induced the formation of unusual spheroplasts. Peptidoglycan turnover in E. coli appeared to be stimulated by sceptrin as demonstrated by a release of diaminopimelic acid-containing high molecular weight material. Subsequent studies of the release of potassium ions from E. coli and the lysis of red blood cells suggested that sceptrin disrupts the cell membranes of both prokaryotic and eukaryotic cells. It is proposed that spheroplasts formation may reflect a cell wall effect that occurs subsequent to membrane damage.

Phenotypes conferred by the Bacillus subtilis recM13 mutation and the din23 fusion

The din23 fusion encodes a B. subtilis SOS-inducible regulatory region fused to the E. coli lacZ gene (Love et al., 1985). A strain encoding the din23 fusion and a recM13 allele showed low-level constitutive beta-galactosidase expression, was induced for beta-galactosidase production by DNA gyrase inhibitors but not by DNA-damaging agents, and was slightly induced by a variety of agents which do not normally induce the SOS regulon. The din23 fusion itself resulted in high levels of spontaneous prophage induction in wild-type, recM- and recA-hosts, despite the fact that the din23recM13 strain was not induced for beta-galactosidase production by DNA-damaging agents. The results suggest that the recM gene may be involved with the regulation of the RecA protease-mediated SOS response, while the din23 gene may be involved with the regulation of an alternative function which results in the cleavage of prophage repressor.

The effect of methylation inhibitors on citreamicin biosynthesis in Micromonospora citrea

When the citreamicin-producing organism Micromonospora citrea NRRL 189351 was incubated in the presence of the methylation inhibitors sinefungin or aminopterin, biosynthesis of the zeta component was stimulated approximately 20 to 200-fold above the level normally produced. Inhibition of a second methylation reaction, which is superficially very similar to the first, was not detected. Other known methylation inhibitors failed to yield any change in the natural pattern of citreamicins produced. This approach is an excellent route for preparing citreamicin zeta, which can be used as a substrate for semi-synthesis or for further biosynthetic studies.

Simaomicin (LL-D42067), a novel antibiotic from Actinomadura madurae. I. Taxonomy, fermentation and biological activity

A new antibacterial antibiotic, designated simaomicin alpha (LL-D42067 alpha) was isolated from the fermentation broth of an actinomycete strain. Based on cultural, physiological, morphological and chemical characteristics, culture LL-D42067 was identified as a new subspecies of Actinomadura madurae. Simaomicin alpha demonstrated potent activity against Gram-positive bacteria and was active in vivo against a variety of Eimeria species causing coccidiosis in chickens.

In vitro inhibition of bacterial DNA gyrase by cinodine, a glycocinnamoylspermidine antibiotic

Cinodine, a broad-spectrum glycocinnamoylspermidine antibiotic, binds to DNA and irreversibly inhibits bacterial and phase DNA synthesis. Cinodine was found to inhibit the activity of Micrococcus luteus DNA gyrase in vitro, but it did not inhibit the activities of two other DNA-binding enzymes, namely, topoisomerase I and BamHI. Although we cannot yet conclude that DNA gyrase is an intracellular target of the drug, in vitro inhibition of the enzyme by cinodine appears to be specific.

LL-D49194 antibiotics, a novel family of antitumor agents: taxonomy, fermentation and biological properties

A novel family of antitumor antibiotics, designated LL-D49194, was isolated from the fermentation broth of an actinomycete strain identified as Streptomyces vinaceus-drappus. LL-D49194 alpha 1 and beta 2 were active against Gram-positive and inactive against Gram-negative bacteria in vitro. The beta 1 component was not active against either Gram-positive or Gram-negative bacteria. These antibiotics exhibited significant in vivo activities against several murine tumors, albeit with differing potencies.

Optical absorption aspects of laser soldering for high density interconnects

In laser soldering, one has direct control over the incident laser pulse energy and duration but only indirect control over the temperature profile of the parts to be soldered. To understand the conversion of incident laser energy into a substrate temperature profile, two processes need to be understood: first, the optical absorption as a function of temperature and, second, the temperature distribution as a function of absorbed energy. The optical absorption aspect is addressed here. A set of total reflectivity measurements for real surfaces of interest is presented along with analytical calculations of the temperature dependence of the optical absorption for both specular and rough surfaces.

LL-E19020 alpha and beta, animal growth promoting antibiotics: taxonomy, fermentation and biological activity

Antibacterial antibiotics LL-E19020 alpha and beta were isolated from the fermentation broth of an actinomycete strain. Based on cultural and physiological characteristics, culture LL-E19020 was identified as a new subspecies of Streptomyces lydicus. The LL-E19020 alpha and beta antibiotics were found to possess a very narrow antibacterial spectrum against human pathogens. In studies in chickens, LL-E19020 alpha demonstrated excellent growth promoting activity.

LL-E19085 alpha, a novel antibiotic from Micromonospora citrea: taxonomy, fermentation and biological activity

A new antibacterial antibiotic, designated LL-E19085 alpha, was isolated from the fermentation broth of an actinomycete strain. Based on cultural, physiological, morphological and chemical characteristics, culture LL-E19085 was identified as a new subspecies of Micromonospora citrea. Antibiotic LL-E19085 alpha demonstrated potent activity against a spectrum of Gram-positive aerobic and anaerobic bacteria.

Calicheamicins, a novel family of antitumor antibiotics: taxonomy, fermentation and biological properties

A novel family of antitumor antibiotics, the calicheamicins, were isolated from the fermentation broth of Micromonospora echinospora subsp. calichensis. These antibiotics exhibited significant activity against Gram-positive and Gram-negative bacteria in vitro. Calicheamicin gamma 1I demonstrated antitumor activity against P388 leukemia and B16 melanoma in vivo.

New antitumor antibiotic, LL-D05139 beta. Fermentation, isolation, structure determination and biological activities

The LL-D05139 complex, containing LL-D05139 beta and azaserine, was recovered from the fermentation filtrate of Glycomyces harbinensis (NRRL 15337). A chemically defined medium was developed which favored the production of LL-D05139 beta. Antibiotic LL-D05139 beta was isolated from the fermentation filtrate by adsorption on granular carbon and further purified by chromatography on microcrystalline cellulose. Acid hydrolysis of LL-D05139 beta gave one molar equivalent each of alanine and serine. Both amino acids were found to have the L-configuration by GC analysis on a chiral column and alanine was assigned to be the N-terminal amino acid by Edman degradation. This information coupled with IR, UV, 1H NMR, 13C NMR and MS spectral data allowed us to assign the structure of LL-D05139 beta as alanylazaserine. LL-D05139 beta demonstrated greater antibacterial and biochemical induction assay activities than azaserine. The two drugs showed similar antitumor activities.

Light-dependent activity of the antitumor antibiotics ravidomycin and desacetylravidomycin

The antitumor antibiotics ravidomycin and desacetylravidomycin were studied by the biochemical lambda prophage induction assay. In this assay, induction of the enzyme beta-galactosidase is measured as a specific indication of the ability of an agent to directly or indirectly damage DNA. Induction was observed only when these two antibiotics were irradiated with light in the presence of the indicator organism. Drug treated with light followed by incubation with the indicator organism in the dark did not cause induction. Light in both the near UV and visible wave length ranges activated these antibiotics; near UV and visible blue wavelengths were most effective, while 597-nm light was totally ineffective. The amount of induction caused by these drugs varied directly with the dosage of light provided. Bacterial growth inhibition, as well as cytotoxicity for a human colon carcinoma cell line, was also dramatically enhanced by light. These data suggest that ravidomycin and desacetylravidomycin are potent photosensitizing, DNA-damaging agents.

Nitrogen repression of gilvocarcin V production in Streptomyces arenae 2064

Analysis of gilvocarcin V production by Streptomyces arenae in complex and chemically defined media revealed strong nitrogen repression of antibiotic biosynthesis. Nitrogen regulation was first suggested by the observation of a 10-fold increase in gilvocarcin V production when the ammonium ion trapping agent Mg3(PO4)2.8H2O was added to complex medium. In a chemically defined medium, cell mass increased as the initial ammonium sulfate concentrations approached 7.5 mM; however, antibiotic production was strongly repressed at ammonium sulfate concentrations exceeding 1.5 mM. Repression of gilvocarcin V production at 7.5 mM ammonium sulfate was maximally reversed by adding Mg3(PO4)2.8H2O to the medium at 25 mM; specific antibiotic production attained a level 2.5-fold higher than at the nonrepressive ammonium salt concentration of 1.5 mM. Evaluation of the effects of soluble inorganic phosphate concentrations upon gilvocarcin V titers suggested that the relatively insoluble Mg3(PO4)2.8H2O must in fact serve as an ammonium ion-trapping agent, as previously reported in other fermentation systems, not as a supplementary source of phosphate for growth and antibiotic production. These studies also revealed a minor repression of antibiotic synthesis at elevated levels of soluble phosphate. Comparisons of several amino acids as nitrogen sources in a Mg3(PO4)2.8H2O-containing medium indicated that L-aspartic acid and glycine promoted the highest yields of gilvocarcin V. Metabolism of these two amino acids into precursors of the polyketide pathway for gilvocarcin V biosynthesis is postulated.

Mechanism of action of cinodine, a glycocinnamoylspermidine antibiotic

The mechanism of action of cinodine, a glycocinnamoylspermidine antibiotic, was investigated. Upon addition of cinodine to growing cultures of Escherichia coli, a rapid decline in viable cell numbers was observed. Culture turbidity continued to increase for a short period before plateauing. Microscopic examination indicated that the antibiotic-treated cells continued to elongate with subsequent formation of serpentine-like structures. Radioisotopic-labeling studies of E. coli demonstrated that deoxyribonucleic acid (DNA) synthesis was immediately and irreversibly inhibited upon addition of cinodine. Ribonucleic acid synthesis was reduced after a significant delay, whereas protein synthesis remained unaffected. There was a minor degree of inhibition of incorporation of radiolabeled diaminopimelic acid into cell wall material. Cinodine likewise inhibited bacteriophage T7 DNA synthesis in infected E. coli cells. After inhibition of E. coli DNA synthesis by cinodine, intracellular DNA degradation was observed. Equilibrium dialysis studies demonstrated that the drug physically bound to DNA. These data indicate that cinodine functions as a potent irreversible inhibitor of bacterial and phage DNA synthesis.

Mucopolysaccharidosis in a cat with arylsulfatase B deficiency: a model of Maroteaux-Lamy syndrome

A Siamese cat that presented clinical signs similar to those seen in humans with mucopolysaccharidoses was studied. The animal excreted increased amounts of polymeric glycosaminoglycans in the urine, consisting almost entirely of dermatan sulfate. Electron microscopy of circulating polymorphonuclear leukocytes revealed the presence of many membrane-bound lamellar inclusion bodies. Sulfate incorporation studies with cultured skin fibroblasts indicated defective glycosaminoglycan degradation. These cells showed a deficiency in arylsulfatase B activity. The disorder appears similar or identical to the Maroteaux-Lamy syndrome described in humans.

Altered growth of hormone secretory pattern following prolonged sleep deprivation in the rhesus monkey

Plasma concentrations of growth hormone (GH) were determined in samples obtained sequentially at 15-min intervals during the last 4 h in monkeys deprived of sleep for 76 h and the first 8 h of ensuing recovery sleep. Electroencephalographic (EEG), electro-oculographic (EOG), and electromyographic (EMG) activities were recorded. Stages 3-4 sleep occurred rapidly after sleep onset and were of long duration. Plasma GH secretion was markedly elevated during sleep recovery, without apparent relationship to stage of sleep.