Вплив солей важких металів на фізіолого-біохімічні характеристики бактерій циклу сірки

Уперше показано, що солі важких металів по-різному впливають на швидкість поглинання кисню клітинами фотосинтезувальних сіркобактерій, і встановлено, що їх внесення у середовище знижує вміст пігментів у клітинах досліджуваних фототрофів. Ці умови спричиняють негативні цитоморфологічні зміни у клітинах бактерій циклу сірки.

Уперше встановлено, що бактерії, які беруть участь у кругообігу сірки в природі, здатні поглинати Cu²⁺, Cd²⁺ та Pb²⁺.

Ключові слова: сульфатвідновлювальні бактерії, сірковідновлювальні бактерії, сіркобактерії, фототрофи, пігменти, важкі метали, ряди токсичності.

АННОТАЦИЯ

Кушкевич И.В. Влияние солей тяжелых металлов на физиолого-биохимические характеристики бактерий цикла серы. - Рукопись.

Диссертация на соискание ученой степени кандидата биологических наук по специальности 03.00.07 - микробиология. Институт микробиологии и вирусологии им. Д.К. Заболотного НАН Украины, Киев, 2010.

Диссертация посвящена изучению влияния солей тяжелых металлов на физиолого-биохимические характеристики бактерий, которые обеспечивают круговорот серы в природе.

В результате проведенной работы впервые показано ингибирующее влияние солей тяжелых металлов на рост бактерий цикла серы и использование сульфат-ионов микроорганизмами Desulfovibrio sp. Ya-11. На основе полученных результатов впервые описаны ряды токсического действия тяжелых металлов на сульфатвосстанавливающие бактерии Desulfovibrio sp. Ya-11: Pb>Cd>Cu; серовосстанавливающие Desulfuromonas sp. Ya-2005: Cd>Cu>Pb>Zn; фототрофные серобактерии Thiocapsa sp. Ya-2003: Cu>Cd>Pb>Zn; Lamprocystis sp. Ya-2003 и Chlorobium sp. Ya-2002: Cu>Pb>Cd>Zn и консорцию Pelochromatium roseo-viridae - Cd>Pb>Cu>Zn.

Впервые показано, что соли тяжелых металлов по-разному влияют на скорость поглощения кислорода клетками фотосинтезирующих серобактерий, их внесение в среду уменьшает содержание пигментов в клетках исследуемых фототрофов. Выявлены негативные цитоморфологические изменения в клетках бактерий цикла серы под влиянием тяжелых металлов.

Впервые установлено, что бактерии, принимающие участие в круговороте серы в природе, способны поглощать Cu²⁺, Cd²⁺ и Pb²⁺.

Ключевые слова: сульфатвосстанавливающие бактерии, серовосстанавливающие бактерии, серобактерии, фототрофы, пигменты, тяжелые металлы, ряды токсичности.

Summary

Kushkevych I.V. Influence of heavy metals salts on physiological and biochemical characteristics of sulfur cycle bacteria. - Manuscript.

A dissertation for the Scholarly Degree of candidate of biological sciences in speciality 03.00.07 - microbiology. D.K. Zabolotny Institute of Microbiology and Virology, NAS of Ukraine, Kyiv, 2010.

This dissertation is devoted to the influence of heavy metals salts on the physiological and biochemical characteristics of bacteria that provide the cycling of sulfur in the nature.

The growth of sulfate- and sulfur-reducing bacteria under the influence of heavy metals salts has been investigated. The inhibitory effect of heavy metals salts on growth of the investigated bacteria is shown. The addition of CdCl₂, Pb(NO₃)₂, and CuCl₂ inhibited the sulfate ions utilization by Desulfovibrio sp. Ya-11 bacteria, but 1.5 mM of ZnCl₂ have stimulated this process. The heavy metals toxicity rows have been obtained for sulfate-reducing bacteria Desulfovibrio sp. Ya-11: Pb>Cd>Cu as well as for sulfur reducing bacteria Desulfuromonas sp. Ya-2005: Cd>Cu>Pb>Zn.

The growth depression of photosynthetic purple, green sulfur cycle bacteria and Pelochromatium roseo-viridae consortium has been determined after the addition of 0.5-2.5 mM of heavy metals salts into the medium. The most sensitive to cadmium salt were P. roseo-viridae bacteria. In comparison with the other investigated cultures, the phototrophic purple sulfur bacteria Lamprocystis sp. Ya-2005 were stable. Zinc sulfate stimulated the growth of bacteria Desulfovibrio sp. ya-11. The highest stability to its influence had the consortion P. roseo-viridae, and the lowest - bacteria Desulfuromonas sp. Ya-2005. Lead nitrate had the lowest influence on the growth of Thiocapsa sp. Ya-2003 in comparison with other cultures. This metal had the highest inhibitory effect on P. roseo-viridae. At the same time the investigated culture had the high stability to the influence of copper salt, which had the most negative influence on the growth of Lamprocystis sp. Ya-2003. The most stable to the negative influence of this metal was P. roseo-viridae.

On the basis of the results of this work the rows of heavy metals toxicity for photosynthetic sulfur cycle bacteria have been described for the first time: for Thiocapsa sp. Ya-2003: Cu>Cd>Pb>Zn; for Lamprocystis sp. Ya-2003 and Chlorobium sp. Ya-2002: Cu>Pb>Cd>Zn, and for P. roseo-viridae: Cd>Pb>Cu>Zn.

The velocity of oxygen uptake by photosynthetic sulfur bacteria with different heavy metals salts concentrations have been determined for the first time. The different influence of heavy metals on the velocities of oxygen uptake has been shown. The addition of some heavy metals salts stimulated this process and the addition of other salts inhibited it.

The quantitative and qualitative contents of the pigments of photosynthetic sulfur cycle bacteria cells under heavy metals salts influence has been investigated for the first time. Heavy metals addition reduced the pigments quantity in the cells of the investigated phototrophes. According to our results, we have obtained the row of metal toxity for pigments synthesis: Cu>Cd>Pb>Zn.

The electron microscopic investigations of the Desulfovibrio sp. Ya-11, Thiocapsa sp. Ya-2003, Lamprocystis sp. Ya-2003, Chlorobium sp. Ya-2002 cells and Pelochromatium roseo-viridae consortion under heavy metals influence has been performed. The cytomorphological changes of the cells after metal salts addition have been studied. The changes were such the accumulation of electronically dense particles inside and outside the cells, the changes in the form of cells, the exfoliation of protoplast from cell wall and the disturbance of cell division processes.

It has been shown for the first time the possibility of sulfur cycle bacteria to accumulate Cu²⁺, Cd²⁺ та Pb²⁺ in conditions of their salts addition to the growth medium.

The obtained results can be used for the isolation of stable to heavy metals salts strains of sulfur bacteria that are able to accumulate the ions of these metals at high concentrations. It is recommended to use these results with the aim to create the universal complex biotechnologies of cells that can be used as biodestructers of these xenobiotics. The changes of physiological and biochemical characteristics of sulfur cycle bacteria under the influence of heavy metals salts can be applied during the selection of biological indicators.

Key words: sulfate-reducing bacteria, sulfur-reducing bacteria, sulfur bacteria, phototrophs, pigments, heavy metals, rows of toxicity.

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