ANTIBACTERIAL ACTION OF A REACTION PRODUCT OF CYSTEINE AND IRON: I. DEVELOPMENT OF THE SUBSTANCE IN MEDIA FOR MYCOBACTERIUM TUBERCULOSIS

1954 ◽  
Vol 1 (3) ◽  
pp. 175-181 ◽  
Author(s):  
Jack Konowalchuk ◽  
N. A. Hinton ◽  
G. B. Reed
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Acid Solution ◽  
Inhibitory Action ◽  
Ferric Iron ◽  
Antibacterial Action ◽  
Ferric Salt ◽  
Low Concentrations ◽  
Acid Reaction

It is shown that the growth of Mycobacterium tuberculosis or a rapidly growing strain of Mycobacterium in Dubos' medium is not influenced by the addition of low concentrations of cysteine or ferric salts, when added separately. But when cysteine and a ferric salt, both in low concentrations, are autoclaved together in the medium, the medium will not support growth of Mycobacterium. This inhibitory action only occurs when the cysteine–iron containing medium is at pH 6.8 or a more acid reaction. It is concluded that cysteine and ferric iron react in acid solution to produce a toxic end product.

scholarly journals Site of inhibitory action of isoniazid in the synthesis of mycolic acids in Mycobacterium tuberculosis

1975 ◽  
Vol 16 (4) ◽  
pp. 308-317
Author(s):  
K. Takayama ◽  
H.K. Schnoes ◽  
E.L. Armstrong ◽  
R.W. Boyle
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Inhibitory Action ◽  
Mycolic Acids

Thermodynamic Simulation of Sulphide Mineral Leaching

2009 ◽  
Vol 71-73 ◽  
pp. 437-440
Author(s):  
Lasse Ahonen ◽  
Pauliina Nurmi ◽  
Olli H. Tuovinen
Keyword(s):  
Acid Solution ◽  
Ferric Iron ◽  
Geochemical Modeling ◽  
Thermodynamic Simulation ◽  
Sulphide Mineral ◽  
Solution Ph ◽  
Dissolved Iron ◽  
Iron Precipitation ◽  
Oxidative Leaching ◽  
Mineral Leaching

Geochemical modeling program PHREEQC was used to simulate generic bioleaching processes. Carbonate minerals (e.g., calcite) dissolve in acid solution, increasing the solution pH and Ca concentration while the concentration of CO2 may be controlled by the equilibrium with the atmospheric CO2. Non-oxidative dissolution of Fe-monosulphides was demonstrated to release H2S and increase the pH. In the absence of ferric iron precipitation (goethite), the oxidation of pyrite decreased the solution pH from 2 to ~1.4, while the oxidation of Fe-monosulphide and chalcopyrite increased the solution pH to ~3.2-3.4. Assuming equilibrium precipitation of goethite, oxidative leaching decreased the solution pH for all three minerals from pH ~2 to ~0.9-1.2. Adjustment of the solution pH to 1.8 or 2.0 with KOH with concurrent equilibrium precipitation of K-jarosite resulted in low dissolved iron concentrations.

Quinoxaline 1,4-di-N-Oxide Derivatives: Are They Unselective or Selective Inhibitors?

2021 ◽  
Vol 21 ◽  
Author(s):  
Gildardo Rivera
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cell Lines ◽  
Mechanism Of Action ◽  
Inhibitory Action ◽  
Triosephosphate Isomerase ◽  
Trypanothione Reductase ◽  
Selective Inhibitors ◽  
Oxide Ring ◽  
Privileged Structure

Background: For decades, the quinoxaline 1,4-di-N-oxide ring has been considered a privileged structure to develop new antibacterial, antitumoural, and antiprotozoal agents, among others, however its mechanism of action is not clear. Objective : The main aim of this mini-review was to analyze the mechanism of action of quinoxaline 1,4-di-N-oxide derivatives reported as antibacterial, antitumoural and antiprotozoal agents. Results : Initially, the mechanism of action of quinoxaline 1,4-di-N-oxide derivatives against bacteria, tumoural cell lines, and parasites has been described as nonspecific, but recently, the results against different organisms have shown that these compounds have an inhibitory action on specific targets such as trypanothione reductase, triosephosphate isomerase, and other essential enzymes. Conclusion: In summary, quinoxaline 1,4-di-N-oxide is a scaffold to develop new anti-Mycobacterium tuberculosis, antitumoural and antiprotozoal agents, however, understanding the mechanism of action of quinoxaline 1,4-di-N-oxide derivatives in each microorganism could contribute to the development of new, and more potent selective drugs.

scholarly journals Mycobacteriocidal Action of Exogenous Nitric Oxide

1999 ◽  
Vol 43 (2) ◽  
pp. 403-405 ◽  
Author(s):  
Richard Long ◽  
Bruce Light ◽  
James A. Talbot
Keyword(s):  
Nitric Oxide ◽  
Mycobacterium Tuberculosis ◽  
Pulmonary Tuberculosis ◽  
Analysis Of Variance ◽  
Time Dependent ◽  
Low Concentrations ◽  
Exogenous Nitric Oxide

ABSTRACT We tested the hypothesis that exposure of extracellularMycobacterium tuberculosis to low concentrations (<100 ppm) of nitric oxide (NO) for short periods (24 h or less) will result in microbial killing. We observed that NO had both dose- and time-dependent cidal effects that were very significant by two-way analysis of variance (F ratios of 13.4 [P< 0.001] and 98.1 [P < 0.0001], respectively). Conceivably, extracellular bacilli in patients with pulmonary tuberculosis might be vulnerable to exogenous NO.

Modulation of Chelidonii herba on GABA Activated Choride Current in Rat PAG Neurons

2001 ◽  
Vol 29 (02) ◽  
pp. 265-279 ◽  
Author(s):  
Yonjung Kim ◽  
Minchul Shin ◽  
Jooho Chung ◽  
Eehwa Kim ◽  
Gyosung Koo ◽  
...  
Keyword(s):  
G Proteins ◽  
Inhibitory Action ◽  
Ion Current ◽  
Aminobutyric Acid ◽  
Patch Clamp Technique ◽  
Gtp Binding ◽  
Inhibitory Modulation ◽  
Low Concentrations ◽  
High Concentrations ◽  
Perforated Patch Clamp

Modulation of Chelidonii herba on γ-aminobutyric acid (GABA) activated chloride current in the acutely dissociated periaqueductal gray (PAG) neuron was studied by nystatin-perforated patch-clamp technique. High concentrations of Chelidonii herba elicited ion current, that was blocked by bicuculline. Low concentrations reduced the GABA activated current in PAG. Two types of inhibitory action of Chelidonii herba on GABA activated current have been implicated in PAG. One is the inhibitory action of Chelidonii herbe on GABA was abolished by naltrexone and the other is that of Chelidonii herba was potentiated by naltrexone. In addition, all of two types of action of Chelidonii herba are linked to pertussis toxin-sensitive GTP-binding proteins. These results suggest that the inhibitory modulation of Chelidonii herba on GABA activated current via G-proteins in PAG neuron is an important analgesic mechanism.

Anthropogenic changes in properties of the water and spatial structure of the vegetation of the lobelia lake Lake Modre in the Bytów Lakeland

2013 ◽  
Vol 42 (3) ◽  
Author(s):  
Marek Kraska ◽  
Piotr Klimaszyk ◽  
Ryszard Piotrowicz
Keyword(s):  
Secchi Depth ◽  
Fish Farming ◽  
Bottom Layer ◽  
Nutrient Elements ◽  
Water Parameters ◽  
Low Concentrations ◽  
Long Term Changes ◽  
Acid Reaction ◽  
Isoetes Lacustris

AbstractLake Modre is a lobelia lake. Numerous typical plant species occur here, including Lobelia dortmanna, Littorella uniflora, Isoetes lacustris, and Sphagnum denticulatum. They develop the following associations: Lobelietum dortmannae (Oswald 1923) Tx. ap. Dierss. 1972, Isoetetum lacustris Szańkowski et Kłosowski 1996 n.n., and a community with Sphagnum denticulatum Brid.In 1991, the water of the lake was characterised by low concentrations of nutrients and calcium, acid reaction (pH<5), and Secchi depth visibility of 12 m. Following fry stocking in the lake in 1993 fish farming took place until approximately 1996. During this period the water quality in the lake changed radically in physiochemical terms. Water transparency decreased. Thermal and oxygen stratification developed, with oxygen deficits in the near-bottom layer. Concentrations of nutrient elements increased.Drastic long-term changes were observed in the spatial and quantitative features of the lake vegetation. These particularly related to the instability of Lobelia dortmanna, and the diminishment of the phytocoenosis of Lobelietum dortmannae. Consequently, the phytocoenosis occurred only in the shallowest part of the phytolittoral. L. uniflora expanded, increasing its occurrence annually. Significant fluctuations in quantities of S. denticulatum occurred, correlated with changes in physiochemical water parameters, but shifted in time.

scholarly journals Virulent but not Avirulent Mycobacterium tuberculosis Can Evade the Growth Inhibitory Action of a T Helper 1–dependent, Nitric Oxide Synthase 2–independent Defense in Mice

2002 ◽  
Vol 196 (7) ◽  
pp. 991-998 ◽  
Author(s):  
Yu-Jin Jung ◽  
Ronald LaCourse ◽  
Lynn Ryan ◽  
Robert J. North
Keyword(s):  
Nitric Oxide ◽  
Mycobacterium Tuberculosis ◽  
Nitric Oxide Synthase ◽  
Inhibitory Action ◽  
Lung Pathology ◽  
T Helper ◽  
Growth Inhibitory ◽  
Ifn Γ ◽  
Control Infection ◽  
Oxide Synthase

Control of infection with virulent Mycobacterium tuberculosis (Mtb) in mice is dependent on the generation of T helper (Th)1-mediated immunity that serves, via secretion of interferon (IFN)-γ and other cytokines, to upregulate the antimycobacterial function of macrophages of which the synthesis of inducible nitric oxide synthase (NOS)2 is an essential event. As a means to understanding the basis of Mtb virulence, the ability of gene-deleted mice incapable of making NOS2 (NOS2−/−), gp91Phox subunit of the respiratory burst NADPH-oxidase complex (Phox−/−), or either enzyme (NOS2/Phox−/−), to control airborne infection with the avirulent R1Rv and H37Ra strains of Mtb was compared with their ability control infection with the virulent H37Rv strain. NOS2−/−, Phox−/−, and NOS2/Phox−/− mice showed no deficiency in ability to control infection with either strain of avirulent Mtb. By contrast, NOS2−/− mice, but not Phox−/− mice, were incapable of controlling H37Rv infection and died early from neutrophil-dominated lung pathology. Control of infection with avirulent, as well as virulent Mtb, depended on the synthesis of IFN-γ, and was associated with a substantial increase in the synthesis in the lungs of mRNA for IFN-γ and NOS2, and with production of NOS2 by macrophages at sites of infection. The results indicate that virulent, but not avirulent, Mtb can overcome the growth inhibitory action of a Th1–dependent, NOS2-independent mechanism of defense.

Epilimnetic Phosphorus Cycling: Influence of Humic Materials and Iron on Coexisting Major Mechanisms

1986 ◽  
Vol 43 (2) ◽  
pp. 302-310 ◽  
Author(s):  
David A. Francko
Keyword(s):  
Alkaline Phosphatase ◽  
Lake Water ◽  
Ferric Iron ◽  
P Uptake ◽  
Humic Material ◽  
Low Concentrations ◽  
Uptake Rates ◽  
Humic Materials ◽  
The Continuum ◽  
Fe Addition

Two major orthophosphate recycling mechanisms, alkaline phosphatase activity and the photodependent release of P from UV-sensitive complex P, cooccurred in epilimnetic samples from four trophically dissimilar lakes in northcentral Oklahoma. Both of these processes were strongly perturbed upon addition of low concentrations of dissolved humic material (DHM) and ferric iron, alone or in concert, to lake water samples. Planktonic orthophosphate uptake rates were also significantly altered by DHM/Fe addition, and, although the majority of P-uptake was accomplished by cells <3.0 μm in diameter, the effects of DHM/Fe were not size-selective. Additions of DHM/Fe to lake water appeared to promote elevated concentrations of orthophosphate and phosphomonoester substrates of alkaline phosphatase in lake water filtrates. Collectively, these data suggest that epilimnetic P cycling may be viewed as a continuum of processes and that the position of a given lake in the continuum is dynamic and influenced by DHM and Fe.

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