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МІНІСТЕРСТВО ОСВІТИ І НАУКИ УКРАЇНИ

Національний авіаційний університет

Інститут екологічної безпеки

Кафедра біотехнології КУРСОВА РОБОТА

(пояснювальна записка)

з дисципліни «Мікробіологія біологічних агентів»

Тема: «Механізми адаптації мікроорганізмів до стресових факторів» Виконала студентка 304 групи

Літвін І.А.

Керівник: Васильченко О.А. Київ 2014

MINISTRY OF EDUCATION AND SCIENCE OF UKRAINEAVIATION UNIVERSITYOF ECOLOGICAL SAFETYOF BIOTECHNOLOGY PAPER

(Explanatory Note)the discipline: “Microbiology of biological agents”: “Mechanisms of microorganism adaptation to stress factors” Student: Litvin IrinaIES 304: Vasylchenko O.A. 2014

CONTENTABSTRACT

INTRODUCTION

. DEFINITIONS

. MECHANISM OF STRESS ADAPTIVE RESPONSE

. STRESS SENSING

. REGULATION OF STRESS-RELATED PROTEIN SYNTHESIS

. GENERAL STRESS RESPONSE

. SPECIFIC STRESS RESPONSES

.1 Heat

.2 Cold

.3 Acid

.4 Osmotic Stress

.5 Oxidative Stress

. MONITORING STRESS RESPONSE

. INDUCTION OF STRESS ADAPTIVE RESPONSE: PRACTICAL CONSIDERATIONS

.1 Heat

.2 Acid

. DETECTING AND QUANTIFYING STRESS RESPONSE

.1 Detection of Stress Response Genes

.2 mRNA Analysis

.3 Detection of Stress Proteins

.4 Biosensors

.5 Measuring Increased Tolerance

. PERSPECTIVES AND AREAS FOR FUTURE WORK

REFERENCES

ABSTRACT

microorganism adaptation stress

Explanatory note to the semester paper “Mechanisms of microorganism adaptation to stress factors” include 26 pages, 9 literary sources. of the study - industrially important microorganisms.- to show different mechanisms of microorganism adaptation to stress factors such as heat, cold, acid, osmotic pressure and so on.methods - analysis, a systematic approach of observation., ADAPTATION, RESISTANCE, SIGMA FACTOR, GENE EXPRESSION, REGULATORY PROTEINS

INTRODUCTION To survive adverse and fluctuating conditions, microorganisms possess mechanisms to recognize diverse environmental changes and mount an appropriate response. Various mechanisms are involved in its activation, depending on the type of stress factor and on the metabolic characteristics of the microorganisms. Microorganisms frequently react simultaneously to a wide variety of stresses and the various stress response systems interact with each other by a complex of global regulatory networks [1]. biological purpose of the stress response is to protect cell components against potentially dangerous environmental factors and to repair damage occurring in stress conditions. The stress response is manifested as a change in the metabolic activity of the cell, resulting from the repression of synthesis of most of the proteins formed in the cell under normal physiological conditions, and induction of the synthesis of a specific group of proteins enabling the cell to function in the new conditions. The biochemical changes are accomplished by physiological changes, such as temporary slowing or stoppage of the division cycle, morphological changes in the cell, or the emergence of resistance to the same stress factor or other types of stress factor [2].can survive under diverse environmental conditions and in order to overcome these adverse and changing conditions, bacteria must sense the changes and mount appropriate responses in gene expression and protein activity. The stress response in bacteria involves a complex network of elements that acts against the external stimulus. Bacteria can react simultaneously to a variety of stresses and the various stress response systems interact (cross-talk) with each other. A complex network of global regulatory systems leads to a coordinated and effective response. These regulatory systems govern the expression of more effectors that maintain stability of the cellular equilibrium under the various conditions [3].bacteria some of the most important stress response systems are:shock response, controlled by the sigma factor sigma 32;stress response, controlled mainly by the sigma factor sigma E and the Cpx two-component system;shock response, which governs expression of RNA chaperones and ribosomal factors;stress response, which depends on the sigma factor sigma S;

(p)ppGpp-dependent stringent response which reduces the cellular protein synthesis capacity and controls further global responses upon nutritional downshift.

Further examples include the secretion of protein domain, TauD , to breakdown taurine into sulphur in times of need and YodA in toxic metal response.

1. DEFINITIONS Stresshas different meanings depending on the context of usage. When used in the field of biology, stress refers to the imposition of detrimental nutritional conditions, toxic chemicals and suboptimal physical conditions (Neidhardt and VanBogelen, 2000). Stress, as used in this term papper, refers to any deleterious factor or condition that adversely affects microbial growth or survival. encountered by microorganisms vary in magnitude and outcome. We use the word “mild” to describe sublethal stress levels that do not result in viability loss, but reduce or arrest growth rate. “Moderate” stress not only arrests microbial growth but also causes some loss in cell viability. “Extreme” or “severe” describes a stress level that is normally lethal to the cells, resulting in death of the majority of the population. Stresses that food microbiota encounter include uncontrollable pre-harvest


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