Bacterial Culture

7 Key excerpts on "Bacterial Culture"

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  eBook - PDF

  Basic Microbiology: A Illustrated Laboratory Manual

  • Khuntia, B K(Authors)
  • 2021(Publication Date)
  • Daya Publishing House

    (Publisher)

  6 Cultivation of Bacteria Bacteria are present universally almost everywhere; in soil, air, water and even inside mouth and intestine of all animals. ‘Cultivation of bacteria’ or ‘bacteria culture’ means growing these minute invisible bacteria in nutritionally rich substances and suitable environmental conditions, which support their rapid growth and multiplication. This results in their manifestation as large population visible to naked eye (as colonies or turbid suspension). Thus, there are two basic requirements for the cultivation of bacteria, such as ( I ) Abundant nutrients and ( II ) Optimum environmental conditions. ( I ) Abundant Nutrients In nature, bacteria take up the complex nutrients available around them after degrading them into simpler forms by the enzymes secreted by them. But in laboratory, rapid growth is augmented by growing them in substances containing nutrients in simpler forms. These substances containing adequate quantity of nutrients in simpler forms for rapid growth and multiplication of bacteria are called ‘culture media’. There are a number of culture media now available containing different ingredients ( See page 59-61 and Appendix I ). Culture media are obtained in the following three ‘physical forms’. 1. Liquid Media or Broth These are clear liquids containing water and nutrients in simpler forms for growth of bacteria, which have been sterilised in autoclave. When bacteria is inoculated into them and incubated in conditions suitable for their growth, they grow profusely into thick suspensions of bacteria cells, due to which the media become turbid. 2. Solid Media This ebook is exclusively for this university only. Cannot be resold/distributed. These are solidified substances, in which liquid broths have been supplemented with a solidifying agent called ‘agar’, at a level more than 1%. Agar is a powder (sometimes called agar agar) extracted from seaweeds and is a complex carbohydrate composed mainly of galactose.

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  Selected Papers in Molecular Biology by Jacques Monod

  • Agnes Ullmann(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  THE GROWTH OF Bacterial CultureS B Y J A C Q U E S M O N O D Pasteur Institute, Paris, France I N T R O D U C T I O N The study of the growth of Bacterial Cultures does not consti-tute a specialized subject or branch of research: it is the basic method of Microbiology. It would be a foolish enterprise, and doomed to failure, to a t t e m p t reviewing briefly a subject which covers actually our whole discipline. Unless, of course, we considered the formal laws of growth for their own sake, an ap-proach which has repeatedly proved sterile. In the present review we shall consider bacterial growth as a method for the study of bacterial physiology and biochemistry. More precisely, we shall concern ourselves with the quantitative aspects of the method, with the interpretation of quantitative data referring to bacterial growth. Furthermore, we shall consider exclusively the positive phases of growth, since the study of bacterial d e a t h , i.e., of the negative phases of growth, involves distinct problems and meth-ods. T h e discussion will be limited to populations considered genetically homogeneous. The problems of mutation and selection in growing cultures have been excellently dealt with in recent review articles by Delbrück (1) and Luria (2). No a t t e m p t is made at reviewing the literature on a subject which, as we have just seen, is not really a subject at all. T h e papers and results quoted have been selected as illustrations of the points discussed. D E F I N I T I O N O F G R O W T H P H A S E S A N D G R O W T H C O N S T A N T S D I V I S I O N R A T E AND G R O W T H R A T E In all that follows, we shall define cell concentration as the number of individual cells per unit volume of a culture and bacterial density as the dry weight of cells per unit volume of a culture. Consider a unit volume of a growing culture containing a t time h a certain number x of cells.

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  An Introduction to Microbiology

  Pharmaceutical Monographs

  • W. B. Hugo, J. B. Stenlake(Authors)
  • 2014(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  CHAPTER 2 BACTERIAL GROWTH AND FACTORS AFFECTING BACTERIAL GROWTH THE CULTIVATION OF BACTERIA The bacterial cell has so far been considered as a single entity; normally, cells are seen collectively as aggregations of many cells on a solid medium which are known as bacterial colonies or in liquid culture conferring turbidity on an originally optically clear medium. The morphology of bacterial colonies is of importance in systematic bacteriology. Bacteria grow in natural habitats such as the soil, water, the ali-mentary tracts of animals and on foodstuffs such as meat and milk, to quote only a few examples. Their presence in the soil is of prac-tical significance. In solutions to be used parenterally, in preserved food, milk and public water supplies, the presence of bacteria is potentially dangerous and the purification of water and preserva-tion of foods and pharmaceutical products is concerned with the elimination or killing of bacteria and other micro-organisms. The chance cultivation of micro-organisms had occurred long before their nature or existence was proved; their growth in carbohydrate-containing media, for example grape juice, to pro-duce alcoholic beverages and their growth on animal carcases producing putrefaction have been known from very early in man's history. For practical study in the laboratory, however, an array of culture media have been evolved, some designed to grow all types of bacteria, others to select from a mixed environment a particular bacterial species. Most culture media used routinely are based on products made from meat extracts, or digests. Partially evaporated aqueous extracts of ox muscle ('Lemco') or dried enzymic or acid digests of muscle tissue, casein or blood fibrin (peptones) form the basis of most culture media. The addi-tion of agar (2 per cent) results in a solid medium, on which isolated colonies can be grown by spreading a culture thinly over the surface of the medium.

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  eBook - ePub

  Bacteriology Methods for the Study of Infectious Diseases

  • Rowena Jenkins, Sarah Maddocks(Authors)
  • 2019(Publication Date)
  • Academic Press

    (Publisher)

  Chapter Two

  Bacterial growth in solid and liquid media

  Abstract

  This chapter will provide readers with basic knowledge needed to culture bacteria successfully in the laboratory. Highlighting the range of growth media available, this chapter should provide readers with confidence to choose appropriate media and culture conditions for experiments they wish to carry out. It will equip readers with an understanding of how to measure bacterial growth by a variety of methods, isolate individual bacterial colonies and use differential and selective media to gain basic information about their Bacterial Culture. There are hints and tips on common issues encountered in each technique described, which should ensure that any Bacterial Culture carried out is problem-free.

  Keywords

  Agar; Broth; Differential media; Growth curve; Selective media; Streak plate; Total viable count

  1. 2.1 Introduction
  2. 2.2 Media, culture conditions and nutritional requirements
     1. 2.2.1 Isolation

  1. 2.3 Differential and selective media
  2. 2.4 Estimating cell number
  3. 2.5 Direct enumeration (viable cells)
  4. 2.6 Notes page

  2.1. Introduction

  The ability to grow and culture different species of bacteria is an essential skill you will need in microbiology. Bacteria are ubiquitous in a vast range of conditions including in soil, water and food, as well as on and inside the human body. As you can imagine, each of these types of bacteria has its own growth requirements and can be cultured successfully only if you provide the correct balance of nutrients in conjunction with appropriate growth conditions, such as optimal temperature and oxygen levels. Once growing, it is essential that you separate the bacteria into individual colonies on agar. This allows you to observe individual characteristics of bacteria and can help identify unknown species within different samples. There is a huge range of media from which to choose when growing bacteria. Many of these contain specific substrates incorporated to aid in identifying bacteria and which reveal the individual characteristics of bacteria. Even if you already know which bacteria you are working with, you still need to be capable of culturing single colonies, because this allows you to confirm that you have not contaminated your work and provides pure single colonies that can then be used to inoculate more complex experiments. This chapter will help you understand the techniques and conditions you need to achieve and maintain pure cultures of bacteria. It also describes the different ways in which you can measure the growth characteristics of your bacteria of interest.

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  Bacterial Physiology

  • C. H. Werkman, P. W. Wilson, C. H. Werkman, P. W. Wilson(Authors)
  • 2013(Publication Date)
  • Academic Press

    (Publisher)

  Many of the properties of growing GROWTH OF BACTERIA 103 cultures are common to all organisms, and as such present generalized functions often reducible to mathematical description. In determining the rate, and to a lesser extent, the initiation and the limits of growth, temperature is also an important variable. Again it should be emphasized that a clear définition and accurate description of the phenomenon associated with the growth of the indi- vidual cell, its morphology and physiology, and the differentiation of these properties from the phenomena associated with the behavior of the culture are essential. II. Quantitative Studies of Bacterial Growth The factors which control bacterial growth are so interrelated as not to lend themselves readily to subdivision and separate consideration. Furthermore, the study of growth in itself has not proved an especially fruitful pursuit; the significance of growth studies of microorganisms has stemmed instead from their value as a tool for the clarification of other aspects of microbiology. The principles governing growth afford a basis for predicting the conditions of environment, nutrition, time, or tempera- ture which will yield cultures, or cells, adequate for a particular study. Monod (1949) has observed that the study of the growth of Bacterial Cultures is not a specialized subject or field of research: it is the basic method of microbiology. With these viewpoints in mind, the discussion of bacterial growth will be subdivided into headings over which a measure of control can be exercised. In so doing, cause and effect relationships are implied, but not insured. Pitfalls are not avoided, but information is gained and a basis for prediction of the response of the organisms is acquired. In this chapter it will be assumed that the factors controlling growth are subject to chemical laws and, however complex, are understandable and interprétable in terms of the chemical processes involved.

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  Microbiology for Water and Wastewater Operators (Revised Reprint)

  • Frank R. Spellman(Author)
  • 1999(Publication Date)
  • CRC Press

    (Publisher)

  For a while, the cells will persist. Some will tolerate the ever-increasing accu-mulation of wastes and will survive on the lysed cellular con-tents of the dead cells. At some point, however, further degrada-tion of conditions will cause even the hardiest organism to die. Microbial Growth 121 The batch processes for growing bacteria are often adequate for various biochemical studies or in plant analyses conducted by water and wastewater specialists. However, since there is usually considerable variation in the ages of the resulting cells and their metabolic activities, the continuous culture technique is used to avoid these variations. Continuous culture allows cells to grow under constant, controlled, defined conditions. Two major types of continuous culture systems are currently in use: chemostats and turbidostats. A chemostat permits control of both the population density and the growth rate of the cul-ture. The turbidostat has a photocell that measures the absorbance (turbidity) of the culture in the growth vessel. CONTINUOUS CULTURE THE EFFECT OF ENVIRONMENTAL FACTORS ON GROWTH The growth of microorganisms is greatly affected by the chemical and physical conditions of their environments. An un-derstanding of environmental influences helps in the control of microbial growth and in the understanding of the ecological dis-tribution of microorganisms. Temperature Temperature is one of the most important environmental fac-tors affecting the growth and survival of microorganisms. In turn, one of the most important factors influencing the effect of temperature upon growth is temperature sensitivity of enzyme- catalyst reactions. As temperature rises, enzyme reactions in the cell proceed at more rapid rates (along with increased meta-bolic activity) and the microorganism grows faster. However, above a certain temperature, growth slows. Eventually, as the temperature continues to increase, enzymes and other proteins are denatured and the microbial membrane is disrupted.

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  Microbial Ecology

  • Allen I. Laskin(Author)
  • 2018(Publication Date)
  • CRC Press

    (Publisher)

  Growth of Bacteria in Mixed Cultures

  Author: J. L. Meers

  Imperial Chemical Industries Ltd.Billingham, TeessideEngland

  Introduction

  Most natural environments (which may be defined as any environment other than a laboratory culture vessel) are constantly subject to invasion by a wide variety of microorganisms. If physicochemical conditions such as temperature, pH, hydration, etc. are within specified limits and the environment contains an available energy source plus the other nutrients required for microbial growth, a microbial community will develop. However, not all species which by chance are transferred to a given environment will become stable members of the community, despite the fact that when grown in axenic (i.e., pure) laboratory culture many more species appear to be capable of growth in a given environment than are in fact found in that environment. Conversely, some species that are found in nature are very difficult to grow as pure laboratory cultures. These apparent contradictions may be reconciled when the importance of the interactions between the component species of mixed microbial populations is appreciated. It is the twofold purpose of this review to discuss the ways in which the growth of one microbial species can affect the growth of another and then to examine specific examples of natural ecosystems with a view to assessing the extent to which recent work has led to an understanding of the complex interrelationships that occur in natural environments.

  With the above terms of reference, the bibliography could become voluminous, therefore only selected references are given, from which various topics may be followed up in greater detail. Although it is evident from the title that the central theme of this review concerns the interactions between bacterial species, some discussion of how the growth of other types of microorganisms affect bacterial growth is included.

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