Role of iron in the enhancement by Agrobacterium tumefaciens infection in mice.
TL;DR: The results obtained help in understanding the host — parasite relationships, regarding bacterial virulence and infection and the growth-promoting effect of iron, as iron promoted the development and progression of serum-exposed A. tumefaciens in mice.
Abstract: Microorganisms require iron for their growth and usually compete with their host for available iron from the system. Iron supplementation to host causes an increase of available iron both to host and to potential microbial invaders and favours the latter more than the former as the bacteria release siderophores which are responsible for iron transport mechanism. In view of this observation a study was done to deal with the distribution of storage and injected iron given as an overload within a physiological pool, taking mice as the host, with a correlation to its utilization byAgrobacterium tumefaciens and with bacterial growth and multiplication. The results obtained help in understanding the host — parasite relationships, regarding bacterial virulence and infection and the growth-promoting effect of iron, as iron promoted the development and progression of serum-exposedA. tumefaciens in mice.
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TL;DR: In this article , the authors investigated the ability of tannic acid, which is ubiquitously present in woody plants, to specifically inhibit the growth and biofilm formation of A. tumefaciens.
Abstract: Agrobacterium tumefaciens underlies the pathogenesis of crown gall disease and is characterized by tumor-like gall formation on the stems and roots of a wide variety of economically important plant species. The bacterium initiates infection by colonizing and forming biofilms on plant surfaces, and thus, novel compounds are required to prevent its growth and biofilm formation. In this study, we investigated the ability of tannic acid, which is ubiquitously present in woody plants, to specifically inhibit the growth and biofilm formation of A. tumefaciens. Tannic acid showed antibacterial activity and significantly reduced the biofilm formation on polystyrene and on the roots of Raphanus sativus as determined by 3D bright-field and scanning electron microscopy (SEM) images. Furthermore, tannic acid dose-dependently reduced the virulence features of A. tumefaciens, which are swimming motility, exopolysaccharide production, protease production, and cell surface hydrophobicity. Transcriptional analysis of cells (Abs600 nm = 1.0) incubated with tannic acid for 24 h at 30 °C showed tannic acid most significantly downregulated the exoR gene, which is required for adhesion to surfaces. Tannic acid at 100 or 200 µg/mL limited the iron supply to A. tumefaciens and similarly reduced the biofilm formation to that performed by 0.1 mM EDTA. Notably, tannic acid did not significantly affect R. sativus germination even at 400 µg/mL. The findings of this study suggest that tannic acid has the potential to prevent growth and biofilm formation by A. tumefaciens and thus infections resulting from A. tumefaciens colonization.
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1,170 citations
"Role of iron in the enhancement by ..." refers background in this paper
...The free serum iron concentration is far below the essential level required for bacterial growth, due to the serum transferrin which has a very high affinity for iron (Weinberg 1978)....
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...The free serum iron concentration of about 1 mol/L (Bullen et al. 1978) in normal serum is far below tha t required for bacterial growth (Weinberg 1978)....
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...1974; Weinberg 1978)....
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TL;DR: From the point of view of infection, a clear distinction must be made between the quantity of iron present in body fluids and its availability to bacteria, which is far too low for normal bacterial growth.
Abstract: Iron is essential for most living things. The importance of the metal lies in its remarkable capacity to engage in electron transport reactions in biological systems (Neilands, 1974). From the point of view of infection, a clear distinction must be made between the quantity of iron present in body fluids and its availability to bacteria. In the living body, iron is not freely available. The bulk of the metal is locked up in ferritin, hemosiderin, myoglobin, and in the hemoglobin in red cells (Lanzkowsky, 1976). The iron-binding proteins, transferrin and lactoferrin, which possess only a minute fraction of the total body iron, are normally only partly saturated with Fe and have an exceptionally high association constant of about 1036 for the metal. This means that the amount of free iron in equilibrium with these proteins is only about 10−8 M, which is far too low for normal bacterial growth. To obtain Fe from normal tissue, bacteria must therefore possess iron chelating agents with association constants similar to those of transferrin and lactoferrin. In injured or dead tissue the situtation may be very different. For example, the lysis of red cells can provide large amounts of Fe for those bacteria that can assimilate heme compounds.
495 citations
TL;DR: It is remarkable that plants and animals have been able to develop, during evolution, methods for keeping many of their tissues and organs free of microbial invaders.
Abstract: WITHIN the past half century, the doctrine of the biochemical unity of living matter has become well established Metabolic pathways as well as methods of storage, transfer, and use of energy and of genetic information are found to have strong commonality in the cells of microorganisms, plants, and animals As a consequence, similar kinds of organic and inorganic components are used in the building of protoplasm by the three forms of life Moreover, the quantities of inorganic nutrilites needed for cell replication are quite similar For example, to achieve maximal growth, cultures of cells of microorganisms, plants, and animals each require approximately 1μM solution of iron, 1 mM solution of phosphorus, and 1 mM solution of magnesium Immunity In view of these similarities, it is remarkable that plants and animals have been able to develop, during evolution, methods for keeping many of their tissues and organs free of microbial invaders
352 citations
"Role of iron in the enhancement by ..." refers background in this paper
...…virulence is the ability of bacteria to multiply in animals, which is usually determined by their ability to compete with their host for essential nutrients, suggesting tha t bacterial nutrition determines the efficiency of bacterial parasitism (Bullen et al. 1974; Weinberg 1975; Kochan 1977)....
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TL;DR: Communications relative to membership In the Association and to all matters of business of the Association should be Communications relative to articles offered for publication addressed to the Administrative Secretary, AAAS, 1515 Masshould be addressed to Editor, 15 15 Massachusetts Avenue, sachusetts Avenue, N. C.W.
Abstract: ScIENcE: A Weekly Journal, since 1900 the official organ Communications relative to advertising should be addressed of the American Association for the Advancement of Science. to THEO. J. CHRISTENSEN, 1515 Massachusetts Avenue, N.W., Published by the American Association for the Advancement Washington 5, D. C. of Science every Friday at Lancaster, Pennsylvania. Communications relative to membership In the Association and to all matters of business of the Association should be Communications relative to articles offered for publication addressed to the Administrative Secretary, AAAS, 1515 Masshould be addressed to Editor, 1515 Massachusetts Avenue, sachusetts Avenue, N.W., Washington 5 D. C. N.W., Washington 5, D. C. Annual subscription, $7.50 Single copies, 25 cents Entered as second-class matter July 18, 1923 at the Post Office at Lancaster, Pa., under the Act of March 3, 1879. o n A pr il 8, 2 01 7
318 citations
"Role of iron in the enhancement by ..." refers background in this paper
...Iron overload was suggested to abolish the inhibitory effect of serum on bacterial growth (Schade and Caroline 1946)....
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TL;DR: There is no single characteristic which could account for the pathogenicity of the non-toxigenic bacteria; some of them survive in the host by being able to multiply rapidly in its tissue fluids and to resist engulfment by his phagocytic cells; oncephagocytized, these bacteria are readily digested by intracellular enzymes.
Abstract: Various bacteria can invade dead or weakened tissues of an animal but only pathogenic parasites are able to establish themselves in viable host tissues and cause disease. To survive in a host and to invade its healthy tissues, a bacterial parasite has to possess mechanisms to neutralize or resist the natural defenses of the host and to use tissues and fluids of the infected body as sources of energy and materials essential for growth. Some pathogens secrete exotoxins which produce symptoms of disease, and, if not neutralized by antitoxins, may cause death. The active or passive acquisition of antibodies to exotoxins usually eliminates toxemia but not infection. Direct destruction of bacteria by specific antibodies and complement occurs only in a few bacterial species. Many pathogens do not produce exotoxins but nevertheless are able to invade tissues of the host, to multiply, and to spread. There is no single characteristic which could account for the pathogenicity of the non-toxigenic bacteria. Some of them survive in the host by being able to multiply rapidly in its tissue fluids and to resist engulfment by his phagocytic cells; once phagocytized, these bacteria are readily digested by intracellular enzymes. Other nontoxigenic parasites are unable to multiply in tissue fluids of the host but survive and multiply in its phagocytic cells. Because of this ability to persist in the intracellular environment, these nontoxigenic bacteria are called facultative intracellular parasites. The diseases caused by facultative intracellular parasites tend to be chronic and their nature is certainly not as acute as that of diseases caused by other bacteria.
226 citations
"Role of iron in the enhancement by ..." refers background in this paper
...Experiments show tha t iron promotes the development of tuberculosis not only in normal but also in immune mice (Kochan 1973, 1975)....
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