Biological Sciences
Microorganisms
Microorganisms are tiny living organisms that can only be seen with a microscope. They include bacteria, viruses, fungi, and protists. Microorganisms play crucial roles in various biological processes, such as nutrient cycling, decomposition, and symbiotic relationships with other organisms. They can also be both beneficial and harmful to human health and the environment.
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10 Key excerpts on "Microorganisms"
- David M. Carlberg(Author)
- 2004(Publication Date)
- CRC Press(Publisher)
1 1 THE SCOPE OF MICROBIOLOGY I. INTRODUCTION Microbiology is the branch of biology that deals with the smallest living things, Microorganisms. These organisms include bacteria, algae, fungi, and protozoa. Viruses, while not living organisms in a strict sense, are also included in the study of Microorganisms, as are subviral infectious particles such as viroids and prions. Microorganisms are universal. They nearly always occur wherever other forms of life are present, but they also thrive in places where environmental conditions are too harsh for other life. Microorganisms are frequently the only living things found at the bottoms of oil wells, for example, or in the hot springs of Yellowstone National Park, ice-covered lakes in Antarctica, and the extremely dry desert soils of Asia and South America. Bacteria that grow in environments at temperatures higher than the boiling point of water have been isolated near volcanic vents deep in the Pacific Ocean. Natural microbial populations can reach unbelievable levels. Common garden soil is particularly rich in Microorganisms. A cubic centimeter (about 1/5 tsp.) may contain as many as 10 9 bacteria, possibly consisting of up to 7000 different species, most of which have not been named. This mass represents 0.3% of the total bulk of the soil. Stated another way, an acre of soil down to a depth of 3 ft contains about 3000 lb of bacteria. Scientists have estimated that bacteria make up about half of all the living biological mass on Earth. The bodies of all animals, including humans, are also rich sources of Microorganisms. As many as a million bacteria may live on each square centimeter of our skin, and saliva may contain 10 9 Microorganisms per milliliter. Nasal washings from normal, healthy adults have been shown 2 Cleanroom Microbiology for the Non-Microbiologist to yield as many as 10 5 Microorganisms per milliliter. Fecal matter contains about 10 11 bacteria per gram, which represents about half its dry weight.
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.
eBook - PDFSpellman's Standard Handbook for Wastewater Operators
Volume I, Fundamental Level, Second Edition
- Frank R. Spellman(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
Virus —The smallest form of Microorganisms; capable of causing disease. 8.4 Microorganisms (IN GENERAL) The Microorganisms we are concerned with are tiny organisms making up a large and diverse group of free-living forms; they exist as single cells, cell bunches, or clusters. Found in abundance almost any-where on Earth, the vast majority of Microorganisms are not harmful. Many Microorganisms, or microbes, occur as single cells (unicellular), others are multicellular, and still others (viruses) do not have a true cellular appearance. A single microbial cell, for the most part, exhibits the characteristic features common to other biological systems, such as metabolism, reproduction, and growth. 8 Microbiology 107 8.4.1 Classification For centuries, scientists classified the forms of life visible to the naked eye as either animal or plant. The Swedish naturalist Carolus Linnaeus organized much of the current knowledge about living things in 1735. The importance of organizing or classifying organisms cannot be overstated, for without a classification scheme it would be difficult to establish crite-ria for identifying organisms and arrange similar organisms into groups. Probably the most important reason for classifying organisms is to make things less confusing (Wistriech and Lechtman, 1980). Linnaeus was quite innovative in his classification of organisms. His binomial system of nomenclature is still with us today. Under the binomial system, all organisms are generally described by a two-word scientific name, the genus and species. Genus and species are groups that are part of a hierarchy of groups of increasing size, based on their taxonomy.
eBook - PDF- Urvashi Swami, Vijay Singh Gondil(Authors)
- 2019(Publication Date)
- Delve Publishing(Publisher)
The chapter then touches upon the history of microbiology in brief. The various types of microbiology are also discussed in this chapter. Microbiology with its innumerable application in diverse fields have also been explained this chapter. The chapter then covers some prospects that this field holds and the challenges it pose for the future. Microbiology plays a significant role in achieving sustainable development goals. Its role in addressing food security and mitigating climate change has been discussed in this section. Finally, the chapter discusses how the fields of microbiology and geology are connected and hence arises the need for the subject geomicrobiology. 1.1 INTRODUCTION Microbiology is a discipline of biology that deals with study of microorgan-isms. Microorganisms and their activities have a significant impact on life on Earth. They are notably involved in almost every process on this planet. Microorganisms are more important for us because they have an impact on all facets of human life. Microorganisms live in humans, on humans and around humans. Microbiology is concerned with the study of organisms that cannot be seen by naked eye due to their extremely small size. They are a diverse group of simple life forms. The field is concerned with the structure, function, and classification of such organisms and look for ways to exploit and control their activities in order to serve humanity. These Microorganisms or microbes are comprised of algae, archaea, bacteria, fungi, protozoa and prions. These microbes have key roles in the following: • Maintenance of nutrient cycle • Process of biodegradation or bio deterioration • Regulation of climate change Introduction to Microbiology 3 • Food spoilage/ decay • Disease and its control • Study of biotechnology A significant role of microbes lies in the process of manufacturing vital medicines which are extremely versatile in their usage.
- 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 - PDF- Stuart Hogg(Author)
- 2013(Publication Date)
- Wiley-Blackwell(Publisher)
I Introduction 1 Microbiology: What, Why and How? Microorganisms (or microbes) inhabit every corner of the globe, and are essential for the maintenance of the world’s ecosystems. They include organ- isms responsible for some of the most deadly human diseases, and others that form the basis of important industrial processes. Yet until a few hundred years ago, nobody knew they existed! This book offers an introduction to the world of Microorganisms, and in this opening chapter, we offer some answers to three questions: What is microbiology? Why is it such an important subject? How have we gained our present knowledge of microbiology? 1.1 What is microbiology? Things aren’t always the way they seem. On the face of it, ‘microbiology’ should be an easy word to define: the science (logos) of small (micro) life (bios), or to put it another way, the study of living things so small that they can’t be seen with the naked eye. Bacteria neatly fit this definition, but what about fungi and algae? These two groups each contain members that are far from microscopic. On the other hand, certain animals, such as nematode worms, can be microscopic, yet are not considered to be the domain of the microbiologist. Viruses represent another special case; they are most cer- tainly microscopic; indeed, most are submicroscopic, but by most accepted definitions they are not living (why? – see Chapter 10 for an explanation). Nevertheless, these too fall within the remit of the microbiologist. Essential Microbiology, Second Edition. Stuart Hogg. C 2013 John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. 4 CH1 MICROBIOLOGY: WHAT, WHY AND HOW? In the central section of this book you can read about the thorny issue of microbial classification and gain some understanding of just what is and what is not regarded as a microorganism. 1.2 Why is microbiology important? To the lay person, microbiology means the study of sinister, invisible ‘bugs’ that cause disease.
eBook - PDFThe Science of Food
An Introduction to Food Science, Nutrition and Microbiology
- P. M. Gaman, K. B. Sherrington(Authors)
- 2013(Publication Date)
- Pergamon(Publisher)
CHAPTER 15 An Introduction to Microbiology Microbiology is the study of Microorganisms (microbes). Microorganisms are very small, usually single-celled, organisms which are not individually visible to the naked eye. They can only be seen with the aid of a microscope. They are widely distributed in the environment and are found in foods. Certain of them, if present in food in large enough numbers, can cause food poisoning. Micro- organisms are the main cause of food 'going off', i.e. food spoilage. However, not all Microorganisms are undesirable. In fact they are essential to all forms of life since they break down complex organic matter and return nutrients to the soil. Microorganisms are used by man in the production of certain foods, e.g. bread and yoghurt. Although some of the effects of Microorganisms have been known and utilised for thousands of years, these microscopic organisms were first seen and studied only 300 years ago. In 1675 a Dutch lens grinder, van Leewenhoek, made a microscope with lenses of sufficiently good quality that he was able to observe Microorganisms in a variety of materials such as teeth scrapings and pond water. The significance of his findings was not appreciated at the time. It was nearly 200 years later that a Frenchman, Louis Pasteur, studied fermentation processes and demonstrated that it was Microorganisms which caused an undesirable sour taste in some wines. He developed a process of heating wine to kill the Microorganisms which caused the souring. This process is still used today to kill undesirable organisms in many food products and is known as pasteurisation. While Pasteur was working in France, Robert Koch, in Germany, demonstrated that anthrax, a fatal disease of sheep and cattle, was caused by a bacterium. From this time onwards great advances were made in the field of microbiology. The organisms responsible for a large number of diseases were identified.
eBook - PDF- Joyce James, Colin Baker, Helen Swain(Authors)
- 2008(Publication Date)
- Wiley-Blackwell(Publisher)
Chapter Seven Microorganisms mixed population of intestinal bacteria (flora) allows us to fight off invading microorgan-isms that enter our bodies by competing for nutrients. Microorganism structure Bacteria The structure of bacterial cells is different from human cells (Fig. 7.1). The most striking differ-ence is the absence of membrane-bound organelles in bacteria and the lack of a defined nucleus. These differences have defined two basic cell types – eukaryotic cells, e.g. animal, plant and fungal cells, which have a membrane-bound nucleus, and the much smaller prokaryo-tic cells, e.g. bacteria which do not. Cell wall Like plant and fungal cells, bacteria have a cell wall but bacterial cell walls contain a unique substance found only in bacteria called muco-peptide. There are two main types of cell wall structure depending on whether an outer lipopolysaccharide (a fat attached to a sugar) Introduction The relevance of Microorganisms to nursing cannot be underestimated. Infections from bac-teria and viruses still cause death despite the discovery of antibiotics and antiviral drugs. Understanding how Microorganisms grow and can be transmitted between humans enables the nurse to establish good practice in his or her working life and explain to patients the impor-tance of hygiene for infection control. Microorganisms Microorganisms include all organisms, which cannot be seen with the naked eye. Bacteria, moulds, yeasts and viruses are included in this group as well as the much larger protozoa, e.g. malaria parasite and giardia. Some common species are listed in Table 7.1. Microorganisms are often thought of as ‘bad’ but some bacteria are essential for our health. For example, in our intestines, commensal bac-teria (bacteria that live in or on our body without causing any effect), keep the atmosphere oxygen free (anaerobic) to allow digestion to be completed and synthesise vitamin K.
eBook - PDF- Rishi Saxena(Author)
- 2023(Publication Date)
- Delve Publishing(Publisher)
Bacterial horizontal gene transfer. Source: Image by Wikimedia Commons It is becoming clear that the microbial world must be taken into account when studying the evolution of all other life forms. A co-evolving community of Microorganisms lives in and on the bodies of all plants and animals, and all macro-organisms evolved in environments filled with billions of interdependent Microorganisms. From the Microorganisms that allow termites to digest wood to those that produce essential vitamins in the human gut, the importance of microbial communities in the health and development of all other organisms raises a rich set of questions for evolutionary biologists. In turn, selective pressures facing plants and animals—their physical environment, diet, and interactions with other species—feed back to affect the evolution of their microbial partners. In considering the impact of antibiotics, which have both saved millions of lives and contributed to the spread of antibiotic resistance mechanisms throughout the microbial world, one begins to appreciate how important it is to understand the interplay between macro-organismal and microbial evolution. On a very practical level, understanding the mechanisms of microbial evolution will further our ability to develop more effective antibiotics and vaccines, predict disease outbreaks and changes in virulence, and harness Microorganisms’ potential for rapid evolutionary change to create new products and processes. The Life of Microorganisms 40 Again and again, discoveries made in microbiology have proven to have universal biological significance, and microbes have served as model systems for many of the most important discoveries in science. In biotechnology, microbial “tools” have found many practical applications, including the cloning of genes from one organism to another using plasmids and phages.
eBook - PDFMicrobiology
Principles and Explorations
- Jacquelyn G. Black, Laura J. Black(Authors)
- 2018(Publication Date)
- Wiley(Publisher)
Determining the Microbial Content of Air Airborne microbes can be detected by collecting those that happen to fall onto an agar plate or in a liquid medium. A special centrifuge-like air-sampling instrument provides a better measure of airborne microbes (Figure 26.10a). (a) (b) FIGURE 26.10 Measuring airborne microbes. (a) An air- sampling device used to measure airborne bacteria and fungi. (Courtesy Graseby Andersen, Inc.) (b) Technicians are protected from the airborne spread of organisms by the use of a laminar flow hood, which suctions air away from the opening and filters it before expelling it. (Will & Deni McIntyre/Science Source) 766 CHAPTER 26 Environmental Microbiology to remove Microorganisms that may have escaped into the air underneath the laminar flow hood. The air is suc- tioned away from the opening, filtered, and then returned to the room. SOIL We might think of the soil we walk on as an inert sub- stance, but nothing could be further from the truth. Soil, in fact, is teeming with microscopic and small macroscopic organisms, and it receives animal wastes and organic matter from dead organisms. Microorganisms act as de- composers to break down this organic matter into simple nutrients that can be used by plants and by the microbes themselves. (Animals, of course, obtain their nutrients from plants or from other animals.) Soil Microorganisms are thus extremely important in recycling substances in ecosystems. Microorganisms in Soil All the major groups of Microorganisms—bacteria, fungi, algae, and protists, as well as viruses—are present in soil, Certain chemical agents, such as triethylene glycol, res- orcinol, and lactic acid dispersed as aerosols, kill many if not all Microorganisms in room air. These agents are highly bactericidal, remain suspended long enough to act at normal room temperature and humidity, are nontoxic to humans, and do not damage or discolor objects in the room.
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