Wyniki wyszukiwania - Biblioteka Nauki

1

Growth and fermentative activities of yeasts Saccharomyces cerevisiae in the presence of killer toxin

100%

Drewicz E. , Kregiel D. , Oberman H.

Biotechnologia

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1999

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nr 2

25-37

EN

Killer yeasts or killer resistant yeasts can be used as starter cultures in fermentative industries to prevent the environments from contamination by wild yeasts. The aim of the work was to investigate the effect of killer yeasts of Saccharomyces cerevisiae T158C, producer of K1 killer toxin, on the wine yeasts Saccharomyces cerevisiae W11, producer of K2 killer toxin, and W6 strain which was sensitive to both toxins. Wine yeasts W6 and killer wine yeats W11 showed different survival rates and fermentative activity in the presence of killer toxin K1 secreted by T158C strain. Obtained results showed that killer yeasts may be usefull when the fermentative conditions (temperature, pH value) will be suitable the activity of killer toxins.

2

Thiol?activated hemolysins as virulence markers of bacteria

100%

Szramka B. , Kurlenda K. J. , Kurlenda J. , Podhajska P. A. J. , Podhajska A. J.

Biotechnologia

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2001

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nr 3

152-168

EN

The article contains information regarding the similarities and differences between proteins of the thiol-activated cytolysins family (TACY). Members of this group of haemolysins are produced by several species of Gram-positive bacteria (Listeria spp., Streptococcus spp., Bacillus spp., Clostridium spp.,) and also by Gram-negative Klebsiella spp.. Their cytolytic activity is sensitive to oxygen and can be restored by adding reducing compounds. TACY bind to cholesterol-containing membranes to form pores. Preincubation of the toxin with small amounts of cholesterol inhibits hemolytic activity as well as cytolysis of eucaryotic cells. Members of the group show 40-70% similarity in amino acid sequence, and contain an almost invariant Trp-rich undecapeptide sequence (ECTGLAWEWWR). The TACY are important virulence factors. Recently increased use has been made of molecular methods (PCR, hybridization) in the detection and identification of the TACY producing bacteria.

3

The influence of yeast killer toxins on the cytotoxicity of shiga-like toxins Part II ? Binding to shiga-like toxin receptors

100%

Salek A. T.

Biotechnologia

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2003

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nr 1

257-266

4

Yeast antimicrobial proteins

88%

Salek A. T.

Biotechnologia

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2001

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nr 4

135-162

EN

Many yeasts secrete proteins which are toxic for pathogenic and non-pathogenic microorganisms. These toxins, mostly glycoproteins, consist of membrane-binding subunits which interact with carbohydrates (e.g. 1,6--D-glucan or -mannan) on the cell wall of sensitive strains. The killing effect is presented by membrane permeation, cell lysis or inhibition of the cell cycle. It is also suggested that these killer glycoproteins, similar in structure to lectins, can mediate self-adhesion of the pathogenic microorganisms, thus stimulating their excretion from the intestines of infected mammals. It is supposed that the above interactions could be important for therapeutic applications, especially for enteric diseases. In order to fully understand the structural basis of the functions of killer glycoproteins, it is essential to characterize their glycosylation state and to determine the structure of all glycans attached to the proteins. In this paper, a strategic approach to the purification of yeast protein from complex biological mixtures is presented. The approach is structured into seven subassignments, each of which is essential for the successful isolation of a pure and biologically active yeast protein. The subassignments are: 1) decision on the use of the purified protein; 2) collecting information about the chemical, physical and biological properties of the protein; 3) establishing assays for the protein and its biological activity; 4) decision on the source of raw material; 5) development of an efficient extraction method; 6) development of a purification method; 7) establishment of optimum conditions for storage of the purified protein.

5

The use of Bacillus thuringiensis in plant protection: prospects and limitations

88%

Malinowski H.

Biotechnologia

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2000

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nr 3

81-92

EN

Taking into account the protection of natural environment, it may be expected that the use of Bacillus thuringiensis toxins to control pest insects will be increased. It results from the discovery of novel toxins with different activity spectra and from the creation of more active toxins with the use of genetic engeeniering techniques. Besides, the introduction of transgenic plants such as cotton, potato, tomato, tobacco and others producing the bacterial toxins against more important species of pest insects will significantly reduce the application of chemical insecticides. The possibility of resistance development in insects poses a great threat to the above strategy. The better recognition of biochemical, physiological and genetical mechanisms of resistance to B. thuringiensis toxins will allow to devise a strategy for delaying jnsects resistance. The general principles of this strategy are similar to those used in the case of chemical insecticides and involve the rational application of B. thuringiensis toxins and their rotation with other insecticides.

6

Functional differentiation of entomopathogenic fungi

88%

Balazy S.

Biotechnologia

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2000

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nr 3

11-32

EN

Entomopathogenic fungi are an interesting object of research due to their great potential for biological control of plant pests and medically important arthropods. As a group, they play an important role in arthropod population density regulation processes together with predators, parasites and other microbial pathogens. A number of species have been selected to be applied in biopesticide technological production. The majority of species known in Poland represent the order of the entomophthorales within Zygomycotina and the hyphomycetous anamorphs of Ascomycotina. Apart from their taxonomical diversity they show strong functional differentiation resulting from enzymatic and toxic activity against their hosts and immunological response of the latter. These phenomena may be considerably modified by environmental conditions. Some aspects of these relationships were discussed and greater attention to their significance for pharmacological and other biotechnologies is suggested.

7

Cyanobacterial toxins in fresh and brackish waters of Pomorskie province (northern Poland)

75%

Mazur H. , Lewandowska J. , Blaszczyka A. , Kot A. , Plinski M.

Oceanological and Hydrobiological Studies

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2003

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nr 1

15-26

EN

Hepatotoxic cyclic peptides and neurotoxic alkaloids are the most common groups of cyanobacterial toxins. They pose a serious threat to human and animal health; each year they are responsible for several cases of animal fatalities (mammals, fish and birds). In Polish water bodies toxic blooms of cyanobacteria are also frequently observed. In this work, a procedure for anatoxin-a analysis has been modified to obtain a sensitive and selective method for routine studies of bloom samples. The presence of cyanobacterial neuro and hepatotoxins in fresh and brackish waters of Pomorskie Province was examined. Hepatotoxins, microcystins or nodularin, were detected in all phytoplankton samples dominated by the cyanobacteria of Microcystis and Anabaena genera or by Nodularia spumigena. HPLC-PDA analysis showed the presence of anatoxin-a only in one sample collected in coastal waters of the Gulf of Gdansk and dominated by Anabaena.

8

Cyanobacteria ? the source of biologically active substances

75%

Glowacka J. , Waleron M. , Szefel-Markowska M. , Lojkowska E. , Waleron K.

Biotechnologia

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2007

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nr 4

95-112

EN

Cyanobacteria (blue ? green algae) are one of the largest group of Gram ? negative, photosynthetic prokaryotes, which are morphologically diverse and highly widespread in salt and sweet water and also in terrestrial habitats. They play a significant role as primary producers in many ecosystems. Some species of Cyanobacteria are capable to grow extensively and formate toxic water blooms which can be dangerous for animal and human health. Certain species of them produce a wide variety of bioactive compounds which can have potential biotechnological cosmetical and pharmaceutical applications. Cyanobacteria have recently been identified as one of the most promising group of organisms from which large number of novel, biochemically active natural compounds can be isolated.