scholarly journals MECHANISMS INVOLVED IN THE ANTIMYCOBACTERIAL ACTIVITY OF CERTAIN BASIC PEPTIDES

1954 ◽  
Vol 99 (1) ◽  
pp. 79-88 ◽  
Author(s):  
James G. Hirsch
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Sulfur Metabolism ◽  
Antimycobacterial Activity ◽  
Posterior Pituitary ◽  
Animal Tissues ◽  
Sulfate Ions ◽  
Basic Peptide ◽  
Posterior Pituitary Gland ◽  
Basic Peptides

The antimycobacterial activity of thymus peptide under certain conditions in vitro can be partially neutralized by increasing the concentration of sulfate ions in the medium, and to a lesser extent by the addition of certain organic compounds which contain sulfur. It is suggested that thymus peptide suppresses the growth of tubercle bacilli by interfering with the normal sulfur metabolism of these microorganisms. Polylysine peptide and pituitary adrenocorticotropic hormone, other basic peptides derived from animal tissues, also inhibit the multiplication of tubercle bacilli in vitro, and their antimycobacterial activity is also antagonized by sulfate ions. Basic peptide hormones prepared from the posterior pituitary gland do not affect the growth of acid-fast bacteria under the conditions of the test.

scholarly journals CHEMICAL STUDIES ON A BASIC PEPTIDE PREPARATION DERIVED FROM CALF THYMUS

1954 ◽  
Vol 99 (1) ◽  
pp. 65-78 ◽  
Author(s):  
James G. Hirsch ◽  
René J. Dubos
Keyword(s):  
Amino Acids ◽  
Antimycobacterial Activity ◽  
Homogeneous State ◽  
Basic Peptide ◽  
Calf Thymus ◽  
Chemical Studies ◽  
Cellulose Membranes ◽  
Basic Peptides ◽  
Peptide Preparation

A substance possessing antimycobacterial activity under certain conditions in vitro has been prepared from aqueous extracts of calf thymus. Chemical studies have demonstrated that the activity of this substance is due to a basic peptide or a mixture of basic peptides. Although this thymus fraction has been shown to be essentially free of compounds other than peptides, it has not been obtained in a homogeneous state. The thymus peptide preparation is soluble in water and in the lower alcohols. Its solubility is minimal between pH 10 and 11, suggesting that its isoelectric point may be in this vicinity. The microbiological activity of thymus peptide is destroyed by acid or alkaline hydrolysis and also by trypsin digestion, but is unaffected by pepsin digestion. Cellulose membranes are permeable to thymus peptide. The most noteworthy finding concerning the amino acid composition of thymus peptide is the preponderance of the basic amino acids lysine and arginine, which together account for about 40 per cent of the weight of this substance. No cystine, and only trace amounts of other amino acids containing sulfur, are present in the thymus peptide preparation.

Serotonergic Neurons and Neuroendocrine Function

Physiology ◽  
1993 ◽  
Vol 8 (5) ◽  
pp. 202-207
Author(s):  
LD Van de Kar ◽  
MS Brownfield
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Adrenocorticotropic Hormone ◽  
Renin Secretion ◽  
Nerve Terminals ◽  
Posterior Pituitary ◽  
Serotonergic Neurons ◽  
Neuroendocrine Function ◽  
Posterior Pituitary Gland

The release of serotonin (5-HT) from nerve terminals in the hypothalamus increases secretion of adrenocorticotropic hormone and prolactin from the anterior pituitary, vasopressin and oxytocin from the posterior pituitary gland, and renin secretion from the kidneys. Activation of 5-HT1 and/or 5-HT2 receptors stimulates the secretion of these hormones.

IN VITRO STUDIES OF THE RELEASE MECHANISM FOR VASOPRESSIN IN RATS

1966 ◽  
Vol 53 (4) ◽  
pp. 644-654 ◽  
Author(s):  
N. A. Thorn
Keyword(s):  
Release Mechanism ◽  
Posterior Pituitary ◽  
High Concentration ◽  
Vasopressin Release ◽  
Pituitary Glands ◽  
Posterior Pituitary Gland ◽  
Stimulation Period ◽  
Releasing Effect

ABSTRACT A study was made of the release of vasopressin activity from groups of isolated posterior pituitary hemilobes of rats, incubated in media with different ionic compositions and with different drugs added to the medium. Nicotine, amyl nitrite and ATP, which have been reported to cause a large in vivo release of hormone had no significant releasing effect in vitro. Caffeine too did not cause any release of hormone activity. About 5% of the vasopressin activity extractable from the isolated posterior pituitary hemilobes was released during stimulation with a high concentration of potassium in the medium. No more than this percentage could be mobilized during such a stimulation, even after further subdivision of the posterior pituitary glands, prolongation of the stimulation period or after increasing the calcium concentration in the medium five-fold. No release into the medium of vasopressin binding protein could be demonstrated during stimulation of vasopressin release. The results seem to be in agreement with the hypothesis that the release of vasopressin is intimately associated with arrival of impulses to the nerve endings in the posterior pituitary gland and that it takes place from a small pool of readily available hormone, presumably by dissociation of the hormone from the carrier protein.

SUCKLING IN THE GUINEA-PIG: THE EFFECTS OF PASSIVE IMMUNIZATION WITH AN ANTISERUM TO OXYTOCIN

1981 ◽  
Vol 90 (2) ◽  
pp. 237-244 ◽  
Author(s):  
I. C. A. F. ROBINSON ◽  
J. A. PARSONS
Keyword(s):  
Mammary Gland ◽  
Passive Immunization ◽  
High Titre ◽  
Immune Serum ◽  
In Vitro Experiments ◽  
Posterior Pituitary ◽  
Milk Ejection ◽  
Posterior Pituitary Gland

Lactating guinea-pigs were passively immunized with an antiserum to oxytocin of high titre, specificity and avidity. Single i.v. injections of 0·1–0·4 ml antiserum produced high titres which decayed slowly (half-life ≃7 days). Passively administered antiserum was effective in vivo; the clearance of exogenous oxytocin from plasma was greatly slowed in immunized animals. Passive immunization with 0·4 ml antiserum reduced milk transfer to the litter during suckling episodes of 10 min, and overall litter growth rates were significantly decreased. Non-immune serum was without effect. Plasma neurophysin levels showed the same large rises during suckling in immunized animals, indicating that neurohypophysial activation was unimpaired. Despite the presence of high titres of antiserum, some milk transfer still occurred at milk ejection. In-vitro experiments showed that more than 25% of oxytocin remained free 20 s after mixing with plasma taken from passively immunized animals. It is probable that the antiserum in the circulation was unable to bind all the oxytocin released from the posterior pituitary gland before it reached the mammary gland.

scholarly journals THE EFFECT OF SPERMINE ON TUBERCLE BACILLI

1952 ◽  
Vol 95 (2) ◽  
pp. 191-208 ◽  
Author(s):  
James G. Hirsch ◽  
René J. Dubos
Keyword(s):  
Antimycobacterial Activity ◽  
Crystalline Substance ◽  
Bactericidal Action ◽  
Organic Base ◽  
Animal Tissues ◽  
Chemical Purification ◽  
Growth Of A Variety ◽  
The Media ◽  
Free Media

A crystalline substance capable of suppressing the growth of a variety of mycobacteria in vitro has been isolated from extracts of tissue in acidified dilute ethanol. This inhibitory material was found to be equally active against virulent, attenuated, and avirulent variants of human and bovine tubercle bacilli, but had little or no effect on saprophytic mycobacteria and on several non-acid-fast microorganisms under the conditions of the test. Its inhibitory activity on the growth of tubercle bacilli was essentially independent of the size of the inoculum within the limits studied. The crystalline material appeared to exert a bactericidal action on the susceptible organisms. Tubercle bacilli maintained in the presence of the agent for 4 days failed to grow when transferred to inhibitor-free media. The findings were not appreciably altered by minor variations in the composition of the medium or by shift in its reaction. When certain preparations of whole serum were used in the medium in place of albumin, no antimycobacterial activity was observed; however, this activity was restored by adding bovine albumin (fraction V) to the media containing whole serum. By chemical purification and analysis, the inhibitory material was identified as spermine, an organic base widely distributed in animal tissues.

Storage and secretion of neurohypophyseal hormones

1968 ◽  
Vol 46 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Frank S. LaBella
Keyword(s):  
Gradient Centrifugation ◽  
Cholinergic Neurons ◽  
Chemical Extraction ◽  
Nerve Terminals ◽  
Posterior Pituitary ◽  
Highly Active ◽  
Pituitary Glands ◽  
Posterior Pituitary Gland

Investigations in the author's laboratory which bear upon several fundamental aspects of the mammalian neurohypophysis were reviewed and related to well-established or currently accepted concepts, (a) The separation of vasopressin-rich from oxytocin-rich neurosecretory granules (NSG) from posterior pituitary homogenates was achieved. (b) The hormone and amino acid composition of isolated NSG was found to be almost identical to that of the van Dyke protein, prepared by chemical extraction of posterior pituitary glands, indicating that the protein is synonymous with the NSG carrier protein to which vasopressin (VP) and oxytocin (OT) are bound. (c) Pinched-off nerve terminals (neurosecretosomes) were isolated from homogenates by centrifugation and shown to be metabolically and morphologically intact. The hexosemonophosphate shunt was highly active in the nerve terminals, where the peptide hormones are stored and secreted, but not in the cell bodies within hypothalamic nuclei, where they are synthesized. (d) Neurosecretosomes relatively enriched in VP were separated from those rich in OT by density-gradient centrifugation, providing support for the concept that a given neurohypophyseal neuron stores and secretes only one of the hormones. (e) Electron microscopy indicated that microvesicles, about 50 mμ in diameter, and called "synaptic" vesicles by some workers, are derived from membranes of depleted NSG and are not of the type that contain neurotransmitter. (f) Acetylcholine (ACh), choline acetyltransferase, and acetylcholinesterase were identified in the posterior pituitary gland and are present in about the same proportions but 1/5 to 1/10 the activity as in whole brain. ACh was found in the neurosecretosome and microvesicle centrifugation fractions. The three cholinergic components in the posterior pituitary are believed to be constituents, not of neurosecretory nerve endings which contain VP or OT, but of specific cholinergic neurons whose role in neurohypophyseal physiology remains to be elucidated. (g) VP and OT are generally released together from the gland in vivo and from posterior pituitary tissue or NSG in vitro. However, exceptions can occur both in vivo and in vitro in which one of the hormones is apparently released exclusively. Studies on the release of VP and OT in vitro show that the NSG–hormone complex is more labile in the case of OT than of VP, an observation that suggests a molecular basis for numerous in vivo findings in which a preponderance of OT over VP is secreted in response to a wide variety of stimuli.

Relations between Structure and Antituberculotic Activity of 4-Alkoxybenzoic Acids

1993 ◽  
Vol 58 (1) ◽  
pp. 191-196 ◽  
Author(s):  
Karel Waisser ◽  
Jiří Kuneš ◽  
Jiří Klimeš ◽  
Miroslav Polášek ◽  
Želmíra Odlerová
Keyword(s):  
Active Compound ◽  
Antimycobacterial Activity ◽  
Methoxybenzoic Acid

Antimycobacterial activity of a series of alkoxybenzoic acids including 4-methoxybenzoic acid (II), 4-ethoxybenzoic acid (III), 4-propoxybenzoic acid (IV), 4-butoxybenzoic acid (V), 4-pentoxybenzoic acid (VI), 4-allyloxybenzoic acid (IX), 4-isopropoxybenzoic acid (VII), 4-isobutoxybenzoic acid (VIII) and 4-benzyloxybenzoic acid (X) has been determined and found to increase with the lipophilicity of the compounds expressed by the corresponding HPLC capacity factors. Also determined were the pKa values of the compounds mentioned. The most active compound, 4-pentoxybenzoic acid (VI), is comparable with commercial antituberculotics when tested in vitro.

scholarly journals ChCl: Gly (DESs) Promote Environmentally Benign Synthesis of Xanthene Derivatives and Their Antitubercular Activity

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3667
Author(s):  
Mashooq A. Bhat ◽  
Ahmed M. Naglah ◽  
Siddique Akber Ansari ◽  
Hanaa M. Al-Tuwajiria ◽  
Abdullah Al-Dhfyan
Keyword(s):  
Reaction Times ◽  
Antitubercular Activity ◽  
Antimycobacterial Activity ◽  
Environmentally Benign ◽  
Reaction Yield ◽  
Benign Synthesis ◽  
Xanthene Derivatives ◽  
Wide Range ◽  
Major Application

A ChCl: Gly (DESs) promoted environmentally benign method was developed for the first time using the reaction of aryl aldehydes and dimedone to give excellent yields of xanthene analogues. The major application of this present protocol is the use of green solvent, a wide range of substrate, short reaction times, ease of recovery, the recyclability of the catalyst, high reaction yield, and ChCl: Gly as an alternative catalyst and solvent. In addition to this, all the synthesized compounds were evaluated for their in vitro antimycobacterial activity against M. tuberculosis H37Ra (MTB) and M. bovis BCG strains. The compounds 3d, 3e, 3f, and 3j showed significant antitubercular activity against MTB and M. bovis strains with minimum inhibitory concentration (MIC) values of 2.5−15.10 µg/mL and 0.26–14.92 µg/mL, respectively. The compounds 3e, 3f, and 3j were found to be nontoxic against MCF-7, A549, HCT 116, and THP-1 cell lines. All the prepared compounds were confirmed by 1H NMR and 13C NMR analysis.

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