Humoral mediator-dependent activation of the Sarcophaga lectin gene

Sarcophaga lectin is a defence protein synthesized by the fat body and secreted into the hemolymph in response to injury of the body of third instar larvae of Sarcophaga peregrina (flesh-fly). In this paper, we demonstrate that the stimulus of body injury is first transmitted to a certain tissue present in the anterior part of the body, and from there a mediator molecule that interacts directly with fat body cells is secreted into the hemolymph. On interaction with this mediator molecule, the fat body begins to synthesize mRNA for Sarcophaga lectin.

Antimycobacterial activities in vitro and in vivo and pharmacokinetics of dihydromycoplanecin A

The in vitro activity of dihydromycoplanecin A (DHMP A), a new cyclic peptide antibiotic, was compared with those of antimycobacterial drugs such as streptomycin, isoniazid (INH), rifampin, and ofloxacin against several clinically isolated species of mycobacteria, including Mycobacterium tuberculosis, M. intracellulare, and M. kansasii. DHMP A demonstrated stronger activities than other drugs against all species of mycobacteria tested at concentrations of less than 0.0125 to 25 microgram/ml. A marked synergism between DHMP A and INH was demonstrated by the checkerboard technique against M. tuberculosis, M. intracellulare, and M. smegmatis, and the synergistic effect was observed by treatment of the culture of M. smegmatis with DHMP A for at least 3 h prior to treatment with INH. It was also shown that both absorption and excretion of INH in mice were faster than those of DHMP A. On the basis of these results, combination therapy with DHMP A and INH was successfully carried out in experimental tuberculosis in mice infected with M. bovis Ravenel. After a single intravenous administration of 10 mg of DHMP A per kg, its half-life in serum in mice was about 0.5 h and in dogs it was 5.5 h. A single oral administration to dogs of 12.5 mg/kg gave a peak of 5.0 micrograms/ml at 3 h. In these experiments, urinary recoveries within 48 h were 21.0% in mice and 25.2% in dogs. The tissue distribution level of DHMP A in mice after oral administration was in the order of liver greater than kidney greater than serum greater than spleen = lung. The 50% lethal doses of DHMP A for mice were more than 6,000 mg/kg orally and 1,840 mg/kg intraperitoneally.

Effects of a new antibiotic, isohematinic acid, on the resistance of mice to experimental infections

Isohematinic acid, an antibiotic newly isolated from the culture broth of Actinoplanes philippinensis SANK 61681, was assessed for its ability to enhance nonspecific resistance to bacterial infections against Escherichia coli and Pseudomonas aeruginosa in mice. This agent, as well as BM 12,531 (Azimexon), was found to prolong the survival of normal mice infected with E. coli and also of compromised mice infected with either E. coli or P. aeruginosa, whose defense system had been deteriorated by treatment with carboquone, an alkylating agent. Like BM 12,531, isohematinic acid administered to normal mice significantly increased the nitroblue tetrazolium reducing potency of polymorphonuclear leucocytes (PMN), indicating that the microbicidal activity of PMN was enhanced by these agents. In addition, in the compromised mice these agents were able to restore the number of peripheral blood leucocytes, which had been reduced to about 30% of the normal level by carboquone. These results suggest that isohematinic acid, like BM 12,531, enhances nonspecific resistance to these bacterial infections by stimulating the microbicidal activity of PMN and inducing leucocytosis.

The calcitonin-like sequence of the beta CGRP gene

We have identified a region within the beta CGRP gene which has the potential to encode a novel calcitonin-like peptide. The gene is located on the short arm of chromosome 11 (11p 12-14.2) and we suggest that it resulted from a local duplication of the alpha gene. We have been unable to detect the corresponding mRNA in a variety of tissues which express alpha-calcitonin. It is not clear whether this sequence can be expressed in man.

Preparation of tyrosine-O-[35S]sulfated cholecystokinin octapeptide from a nonsulfated precursor peptide

A rapid and simple one-pot method for O-sulfation of nonsulfated cholecystokinin octapeptide (CCK-8) was developed using sulfuric acid and dicyclohexylcarbodiimide (DCC) without protection of the amino acid side chains. The extent of sulfation was increased with increasing the amount of reactants, sulfuric acid, and DCC, and reached maximum (40%) with fourfold molar excess of sulfuric acid and 40-fold molar excess of DCC. The excess of nonsulfated peptide inhibited the sulfation. The sulfation product was purified by HPLC or TLC to give a pure sulfated substance which showed exactly the same behavior as that of an authentic O-sulfated CCK-8 on HPLC or TLC. The purified sulfated peptide was active in stimulating amylase secretion from rat pancreatic fragments, and amino acid analysis showed that the tyrosine residue in the peptide existed in O-sulfated form. Sulfation with [35S]sulfuric acid-DCC produced a radioactive substance, from which O-[35S]sulfated CCK-8 could be easily purified by two-dimensional TLC.

Analysis of the DNase I-hypersensitive site of a developmentally regulated 25-kDa protein gene of Sarcophaga peregrina

Change in chromatin structure of a developmentally regulated gene of Sarcophaga peregrina (flesh fly) during development was investigated. This gene (25-kDa protein gene) was specifically activated in the fat body, but not the hemocytes of larvae in the middle of the third instar. The mRNA level in the fat body decreased thereafter, reaching one-fifth of the maximum level in the late third instar to early pupal stage. In the chromatin of fat body nuclei, a DNase I-hypersensitive site was found about 300 base pairs upstream from the transcription initiation site of the 25-kDa protein gene. This DNase I-hypersensitive site appeared before activation of the 25-kDa protein gene, and it was conserved until the late third instar, but disappeared in the early pupal stage. Since activity of the 25-kDa protein gene decreases significantly in the early pupal stage, it is likely that disappearance of this DNase I-hypersensitive site coincides with inactivation of the 25-kDa protein gene.

Aculeximycin, a new antibiotic from Streptosporangium albidum. II. Isolation, physicochemical and biological properties

A new larvicidal antibiotic, aculeximycin, was found in the culture broth of an actinomycete identified as Streptosporangium albidum. Aculeximycin was isolated from the culture filtrate by adsorption on a Diaion HP-20 column and successive elution with acidic aqueous acetone. It was extracted from the concentrated active fraction with 1-butanol and subjected to column chromatography on a Sephadex LH-20 column. Aculeximycin exhibited strong larvicidal activity against mosquito larvae as well as antimicrobial activities against Gram-positive and Gram-negative bacteria, yeasts and molds.

Mycoplanecins, novel antimycobacterial antibiotics from Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. II. Isolation, physico-chemical characterization and biological activities of mycoplanecin A

New antibiotics, mycoplanecins, were found in the culture broth of an actinomycete identified as Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. Mycoplanecin complex was extracted with organic solvents both from the culture filtrate and mycelium and purified by column chromatography on silica gel and Florisil. Mycoplanecin A, a major component, was separated by high performance liquid chromatography on Prep PAK-500/C18 column. The physico-chemical characterization revealed that mycoplanecin A was a new cyclic peptide antibiotic. Mycoplanecins exhibited strong activities primarily against mycobacteria and related microorganisms.

Antifungal activity of transferrin

Inhibitory effects of transferrin on fungal growth were successfully estimated by measuring fungal ATP content. By this method, it was demonstrated that both human and rabbit transferrin possessed the inhibitory effect in the absence of any other factor on yeast-like and filamentous fungi. However, rabbit stimulation factor enhanced the inhibitory effect. The inhibitory effect of transferrin was nonspecific and correlated with unsaturated iron binding capacity (UIBC) of transferrin. Human transferrin was more inhibitory than rabbit transferrin.

The effects of amino acids on the labellar hair chemosensory cells of the fly

The effects of amino acids on the labellar hair chemosensory cells were examined with two kinds of flies (the fleshfly, Boettcherisca peregrina, and the blowfly, Phormia regina). As a result of this examination, the effects of amino acids were divided into four main classes. Amino acids in class 1 did not stimulate any chemoreceptor cell. Amino acids in class 2 inhibited nonspecifically the discharges from three kinds of chemosensory cells. Amino acids in class 3 stimulated the salt receptor cell. Amino acids in class 4 stimulated the sugar receptor cell. A possibility that a fourth neuron in the labellar hair chemosensory cell might be a protein or an amino acid receptor cell was eliminated.

The effects of pH on the labellar sugar receptor of the fleshfly

Reproducible results describing the effects of pH on the response of the labellar sugar receptor of the fleshfly, Boettcherisca peregrina, were obtained. The response to sucrose was independent over a wide range of pH (3.0 to 10.0 for sucrose stimulation), but was inhibited fairly sharply on both sides of this range. Similar results were obtained for monosaccharide stimulation. The receptor was excited on stimulation by water above pH 12.0. The effects of high pH, both inhibitory and excitatory, were affected by the presence of salts. In the presence of 0.5 molar NaCl, for example, the pH-inhibition curve was shifted toward lower pH's by about one pH unit. The effects of low pH, on the other hand, were not affected by salts. Following Dixon's theory, it was concluded that at least five ionizable groups (loosing positive charges above pH 10.5) were located at the receptor site.

Stimulation of the labellar sugar receptor of the fleshfly by mono- and disaccharides

Responses of the labellar sugar receptor of the fleshfly, Boettcherisca peregrina, were studied over a wide range of concentrations of several sugars (sucrose, maltose, glucose, fructose, and mannose) in single solutions and in mixtures. The results suggest (a) that the receptor sites are not completely differentiated for glucose and for fructose combination, (b) that the receptor site is composed of two subunits. Such suggestions are based on the classical model, where the response is proportional to the number of the sites, two subunits of each site being simultaneously occupied with one molecule of disaccharides or two molecules of monosaccharides. It is shown, however, that an allosteric model gives a somewhat better interpretation of the experimental results.

Stimulation of the labellar sugar receptor of the fleshfly by mono- and disaccharides

Responses of the labellar sugar receptor of the fleshfly, Boettcherisca peregrina, were studied over a wide range of concentrations of several sugars (sucrose, maltose, glucose, fructose, and mannose) in single solutions and in mixtures. The results suggest (a) that the receptor sites are not completely differentiated for glucose and for fructose combination, (b) that the receptor site is composed of two subunits. Such suggestions are based on the classical model, where the response is proportional to the number of the sites, two subunits of each site being simultaneously occupied with one molecule of disaccharides or two molecules of monosaccharides. It is shown, however, that an allosteric model gives a somewhat better interpretation of the experimental results.