Biological Sciences
Types of Bacteria
Bacteria can be classified into different types based on their shape, structure, and staining characteristics. Common types include cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped) bacteria. Bacteria can also be categorized based on their need for oxygen, such as aerobic (require oxygen) and anaerobic (do not require oxygen) bacteria. These classifications help in understanding the diversity and characteristics of bacterial organisms.
Written by Perlego with AI-assistance
Related key terms
1 of 5
7 Key excerpts on "Types of Bacteria"
eBook - ePub- Britannica Educational Publishing, Kara Rogers(Authors)
- 2010(Publication Date)
- Britannica Educational Publishing(Publisher)
CHAPTER 3Types of BacteriaM illions of years of evolution have given rise to extraordinary metabolic diversity among prokaryotes, which is reflected in the countless different Types of Bacteria present on Earth. However, precisely how many different Types of Bacteria inhabit Earth is unknown. In fact, finding ways to accurately estimate the number of different bacterial species in various ecosystems, such as oceans and forest soils, is an important area of research. Understanding microbial diversity, which forms part of the larger endeavour of cataloguing all Earth’s life-forms, promises to broaden scientists’ knowledge of the fundamental roles of bacteria in nature and to identify new applications in biotechnology and industry.APPROACHES TO BACTERIAL CLASSIFICATION
Bacteria can be systematically separated into groups on the basis of morphological or shared evolutionary relationships. Today the classification of bacteria is grounded primarily in genetics. However, whereas genetic classification is valuable in understanding evolutionary relationships, morphological and biochemical features continue to play important roles in the functional identification and grouping of bacteria, particularly for the purposes of medicine.CLASSIFICATION BY GENETIC DIVERGENCEGenetic approaches to the classification of bacteria are aimed at identifying a degree of relatedness between organisms to obtain a more fundamental measure of the time elapsed since two organisms diverged from a common ancestor. The specific region of DNA that has proved to be the most informative for evolutionary relatedness is 16S rRNA , the gene that encodes the RNA component of the smaller subunit of the bacterial ribosome (16S refers to the rate of sedimentation, in Svedberg units, of the RNA molecule in a centrifugal field). The 16S rRNA gene is present in all bacteria, and a related form occurs in all cells. The 16S rRNA gene of E. coli is 1,542 nucleotides long, and some of its regions are double-stranded, while other regions are single-stranded. Single-stranded regions often form loops because there is a lack of complementary bases on the opposing strand. Since 16S rRNA
eBook - PDF- H W Doelle(Author)
- 1994(Publication Date)
- WSPC(Publisher)
CHAPTER 1 Microbial Types and Technology 1. Microbial Types One of the great unifying theories of biology is, that the cell is the fundamental unit of a l l living matter. A single cell is an entity, isolated from other cells by a cell wall or membrane and containing within i t a variety of materials and subcellular structures. Depending on their detailed structures, the biological types of catalysts are divided into two large groups: PROKARYOTES : bacteria and viruses. EUKARYOTES : algae, yeast, and fungi. Viruses are not in general regarded as cell types, as they lack many attributes of a cell and acquire the attributes of a living system only when associated with a c e l l . Microbiologists use the bionomal system of nomenclature f i r s t developed for the plant and animal kingdoms to name the microorganisms. The genus name is given to related organisms and different types of organisms within the genus are given species names. Both are always used together. O VIRUS IS - ISO nm ( ) RICKETTSIA 3S0 nm I V ' > EUKARYOTIC ORGANISMS C ^ BACTERIUM 1 * m j0Q00flpiP!>P!RaQ^^ YEAST 5 Jim •^'••>/V•^^•^^•Vv>/>X^•^^;>••;••: FUNlM 10lim L PROKARYOTIC ORGANISMS ANIMAL CELL 5 - 30 * m f PLANT CELL 10 - 100 j i m Figure 1.1: Size of microorganisms 5 6 Microbial Process Development 1.1 Prokaryotes Prokaryotic cells are the simplest l i v i n g cells in terms of structure and are very small (Fig. 1.1). They can be made visible under the normal light microscope by various staining methods. One of the most important staining procedures in microbiology i s the differential GRAM stain. On the basis of their reaction to this GRAM stain, bacteria are divided into two groups, Gram-negative and Gram-positive and indicates fundamental differences in the c e l l wall structure. To study the internal structure of prokaryotes, an electron microscope is essential (Fig. 1.2).
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. However, most bacteria have not been characterised, and only about half of the phyla of bacteria have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology. There are approximately ten times as many bacterial cells in the human flora as there are human cells in the body, with large numbers of bacteria on the skin and as gut flora. The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, and a few are beneficial. However, a few species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people a year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and in agriculture, so antibiotic resistance is becoming common. In industry, bacteria are important in sewage ________________________ WORLD TECHNOLOGIES ________________________ treatment, the production of cheese and yogurt through fermentation, as well as in biotechnology, and the manufacture of antibiotics and other chemicals. Once regarded as plants constituting the Class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved independently from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.
eBook - PDF- F Cunningham(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
CHAPTER 2 Types of Microorganisms Daniel Y. C. Fung Food Science Graduate Program Kansas State University Manhattan, Kansas 66506 I. M I C R O B I A L W O R L D Microorganisms are minute living entities too small to be seen by the naked eye. They are ubiquitous in our environment and under proper growth conditions can affect our daily lives. All living things less than 0.1 mm in diameter fall into the world of microbes. The refinement of the lens by Antony van Leeuwenhock in the 1670s allowed him to dis-cover the existence of these microbes. The microbial world includes viruses, bacteria, yeasts, molds, protozoa, and algae. Microorganisms are beneficial to humans through their roles in the various geochemical cycles such as the phosphorous, carbon, oxygen, nitrogen, and sulfur cycles; without microbes the earth would not be livable for humans. They are also important in various fermented foods such as wine, cheese, beer, vinegar, bread, and soybean products and in the produc-tion of industrially important acids, solvents, antibiotics, steroids, en-zymes, etc. They can even be eaten as foods such as mushroom, yeast, and single-cell protein. However, they can also spoil our food supplies and cause devastating diseases in animals and humans. From the standpoint of the microorganisms, however, they are simply trying to fulfill their biological activities of growth and perpetuation in the form of sexual and asexual reproduction. They need water, carbohy-drate, protein, fat, minerals, vitamins, and the right combination of gases, temperature, pH, and other conditions in order to grow and to multiply. Therefore, there are no good or bad microorganisms in nature; it is according to how they affect us that we consider them harmful or beneficial (Fung, 1983). THE MICROBIOLOGY OF POULTRY MEAT PRODUCTS Copyright © 1987 by Academic Press, Inc. All rights of reproduction in any form reserved.
- Chandra, Ram(Authors)
- 2021(Publication Date)
- Daya Publishing House(Publisher)
Chapter 13 Biodiversity of Microorganism in Different Area and its Ecological Importance Shika Jain 1 , Yogesh Franklin 1 * , Dinesh K. Kumawat 1 and B.M. Meena 2 1 Department of Food Microbiology, College of Dairy and Food Science Technology , 2 Department of Entomology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan Introduction The overwhelming majority of biological diversity is microbial. Microorganisms span all three domains of life and are typically defined as unicellular life forms that can only be observed with a microscope, including bacteria, archaea, viruses, and many unicellular eukaryotes (e.g ., some fungi and protists). Although it might not be immediately obvious, our world is a microbial one. Biodiversity is usually discussed in terms of large organisms, but no organisms are more ubiquitous, abundant, or diverse than microorganisms. Microorganisms were the first cellular life forms and were active more than 3 billion years prior to the appearance of macro-organisms. The metabolic activities that they carried out during this time were critical for creating the conditions for the evolution of multicellular forms. The universal tree of life ( Figure 13.1 ) emphasizes this point; multicellular eukaryote is crown groups compared with the deeply rooted Bacteria and Archaea. Microbes force us to stretch our imagination about the limits of metabolic lifestyles, the geography of life, and the roles that organisms play in our lives. This ebook is exclusively for this university only. Cannot be resold/distributed. Figure 13.1 : The Universal Tree of Life Showing the Position of Archaea and Bacteria Relative to Eucarya. The placement of organisms on this phylogenetic tree is based on the analyses of SSU rRNA sequences of organisms from within each domain.
eBook - PDFMicrobial Biotechnology
Fundamentals of Applied Microbiology
- Alexander N. Glazer, Hiroshi Nikaido(Authors)
- 2007(Publication Date)
- Cambridge University Press(Publisher)
Serovar (or serotype) refers to distinctive antigenic properties, and biovar (or bio- type) is applied to strains with special biochemical or physiological proper- ties. In principle, any group of organisms can be classified according to any set of criteria, as long as the scheme results in reproducible identification of new The Importance of the Identification and Classification of Microorganisms 11 TABLE 1.4 Ranking of taxonomic categories Category Examples Domain Archaea Bacteria Fungi Phylum Crenarchaeota Proteobacteria Ascomycota Class Thermoprotei α-Proteobacteria Saccharomycetes Order Sulfolobales Legionellales Saccharomycetales Family Sulfolobaceae Legionellaceae Saccharomycetaceae Genus Sulfolobus Legionella Saccharomyces Species Sulfolobus acidocaldarius Legionella pneumophila Saccharomyces cerevisiae strains. However, a classification scheme based on totally arbitrary criteria is likely to be of very limited practical use. Thus taxonomists may group together apparently similar, presumably related species into a genus and presumably related genera into a family in the hope that this classification accurately reflects the evolutionary or phylogenetic relationships among various organisms. A hierarchical classification of this type was still being used by the recognized authority in prokaryote taxonomy, Bergey’s Manual of Determinative Bacteriology (ninth edition), in 1994. But how does one build such a taxonomic scheme? To classify a microor- ganism in this manner, one must first obtain a large uniform population of individuals, a pure culture. In the traditional methods of taxonomy, one then examines the organism’s phenotypic characters – that is, the properties that result from the expression of its genotype, which is defined as the complete set of genes that it possesses.
eBook - PDF- Urvashi Swami(Author)
- 2020(Publication Date)
- Delve Publishing(Publisher)
Soil Bacteria 3 CONTENTS 3.1 Introduction ....................................................................................... 50 3.2 Characteristics of Soil Bacteria ........................................................... 51 3.3 The Role of Soil Bacteria In The Soil ................................................... 52 3.4 Types of Soil Bacteria ......................................................................... 54 3.5 Benefits of Soil Bacteria ..................................................................... 65 3.6 Management of Soil Bacteria ............................................................. 67 Chapter Soilborne Pathogens 50 3.1 INTRODUCTION Soil bacteria are single-celled organisms living in the soil. So very tiny, soil bacteria are found in millions. For instance, a teaspoon of soil contains around 1 billion bacteria. Soil bacteria just like soil fungi may be classified into their major functional groups. • The first group involves decomposer soil bacteria. They consume plant residues and their exudates from roots or even plants litters. They also participate in the breakdown of pesticides and other pollutants in the soil. • The second group of soil bacteria involves mutualistic soil bacteria. Their main role is to establish a mutual relationship with plants. They relate mutually with plants in symbiotic or non-symbiotic relationship. A good example is nitrogen-fixing bacteria. • The third group of soil bacteria involves pathogenic soil bacteria. They act as parasites on plants and may cause diseases and other devastating effects on plants if not checked. • The last group consists of lithotrophic bacteria. They mainly obtain their energy from iron nitrates and other compounds instead of carbohydrates from plants. Their main role is breaking down pollutants and nitrogen cycles. It is important to know the soil bacteria from various functional groups are involved in water retention, movement of nutrients and disease suppression.
Index pages curate the most relevant extracts from our library of academic textbooks. They’ve been created using an in-house natural language model (NLM), each adding context and meaning to key research topics.
