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1.3.4: Modern Microbiology - Biology

1.3.4: Modern Microbiology - Biology


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LEARNING OBJECTIVES

  • Discuss the fundamental aspects of microbiology

Modern microbiolgy began with the discovery of microbes, and the scope and scale of the field continues to expand today. While there is some debate, modern microbiology is accepted by most to begin with observations by the Dutch draper and haberdasher, Antonie van Leeuwenhoek, who lived for most of his life in Delft, Holland. In 1676, van Leeuwenhoek observed bacteria and other microorganisms, using a single-lens microscope of his own design. While van Leeuwenhoek is often cited as the first to observe microbes, Robert Hooke made the first recorded microscopic observation, of the fruiting bodies of molds, in 1665.

It has been suggested that a Jesuit priest called Athanasius Kircher was the first to observe microorganisms. One of his books contains a chapter in Latin, which reads in translation – “Concerning the wonderful structure of things in nature, investigated by Microscope.” Here, he wrote “who would believe that vinegar and milk abound with an innumerable multitude of worms. ” He noted that putrid material is full of innumerable creeping animalcule. These observations antedate Robert Hooke’s Micrographia by nearly 20 years and were published some 29 years before van Leeuwenhoek saw protozoa.

The field of bacteriology (later a subdiscipline of microbiology) was founded in the 19th century by Ferdinand Cohn, a botanist whose studies on algae and photosynthetic bacteria led him to describe several bacteria including Bacillus and Beggiatoa. Cohn was also the first to formulate a scheme for the taxonomic classification of bacteria and discover spores. Louis Pasteur and Robert Koch were contemporaries of Cohn’s and are often considered to be the father of microbiology and medical microbiology, respectively. Pasteur is most famous for his series of experiments designed to disprove the then widely held theory of spontaneous generation, thereby solidifying microbiology’s identity as a biological science. Pasteur also designed methods for food preservation (pasteurization) and vaccines against several diseases such as anthrax, fowl cholera, and rabies.

Koch is best known for his contributions to the germ theory of disease, proving that specific diseases were caused by specific pathogenic microorganisms. He developed a series of criteria that have become known as the Koch’s postulates. Koch was one of the first scientists to focus on the isolation of bacteria in pure culture resulting in his description of several novel bacteria including Mycobacterium tuberculosis, the causative agent of tuberculosis. While Pasteur and Koch are often considered the founders of microbiology, their work did not accurately reflect the true diversity of the microbial world because of their exclusive focus on microorganisms having direct medical relevance.

It was not until the late 19th century and the work of Martinus Beijerinck and Sergei Winogradsky, the founders of general microbiology (an older term encompassing aspects of microbial physiology, diversity, and ecology), that the true breadth of microbiology was revealed. Beijerinck made two major contributions to microbiology: the discovery of viruses and the development of enrichment culture techniques. While his work on the tobacco mosaic virus (TMV) established the basic principles of virology, it was his development of enrichment culturing that had the most immediate impact on microbiology by allowing for the cultivation of a wide range of microbes with wildly different physiologies. Winogradsky was the first to develop the concept of chemoautotrophy and to thereby reveal the essential role microorganisms played in geochemical processes. Specifically, he was responsible for the first isolation and description of both nitrifying and nitrogen-fixing bacteria.

Key Points

  • There is some debate as to who was exactly first, but Antonie van Leeuwenhoek, Athanasius Kircher, and Robert Hooke were the first people to view microbes using some of the first self-built microscopes.
  • Ferdinand Cohn, Louis Pasteur, and Robert Koch were pioneers in bacteriology, the discovery and understanding of the subset of microbes that are bacteria. This had a direct and immediate impact on food storage and disease causality.
  • Martinus Beijerinck and Sergei Winogradsky are credited with the discovery of general microbiology, which laid the ground work for our understanding of microbial physiology, diversity, and ecology.

Key Terms

  • chemoautotrophy: When a simple organism, such as a protozoan, derives its energy from chemical processes rather than photosynthesis.
  • pasteurization: heat-treatment of a perishable food to destroy heat-sensitive vegetative cells followed by immediate cooling to limit growth of the surviving cells and germination of spores
  • rabies: a viral disease that causes acute encephalitis in warm-blooded animals and people, characterised by abnormal behaviour such as excitement, aggressiveness, and dementia, followed by paralysis and death
  • animalcule: An older term for a minute or microscopic animal or protozoan.

Fungi that Infect Humans

Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides the Cryptococcus spp. that infect immunocompromised as well as healthy humans and important pathogens of immunocompromised patients-Candida, Pneumocystis, and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.


Introduction

The adenoviruses are common pathogens of humans and animals. Moreover, several strains have been the subject of intensive research and are used as tools in mammalian molecular biology. More than 100 serologically distinct types of adenovirus have been identified, including 49 types that infect humans. The family Adenoviridae is divided into two Genera, the mammalian adenoviruses (mastadenoviruses) and the avian adenoviruses (aviadenoviruses). The adenoviruses are named after the human adenoids, from which they were first isolated.

Several adenoviruses can cause respiratory and conjunctival diseases. In addition, a few types of human adenoviruses induce undifferentiated sarcomas in newborn hamsters and other rodents and can transform certain rodent and human cell cultures. There is currently no evidence that adenoviruses are oncogenic in humans, but the possibility remains of interest.


Biology news

Synthetic biology offers a way to engineer cells to perform novel functions, such as glowing with fluorescent light when they detect a certain chemical. Usually, this is done by altering cells so they express genes that can .

Loss of biodiversity in streams threatens vital biological process

The fast-moving decline and extinction of many species of detritivores—organisms that break down and remove dead plant and animal matter—may have dire consequences, an international team of scientists suggests in a new .

Same dance, different species: How natural selection drives common behavior of lizards

A surprising study on the behavior of unrelated lizards demonstrates how evolution can lead to different species learning the same skills.

How food production emissions are harming health

While increased agriculture production has reduced hunger, it is also linked to unhealthy diets and increased emissions that are severely affecting human health, says a study.

Microbes in cow stomachs can break down plastic

Plastic is notoriously hard to break down, but researchers in Austria have found that bacteria from a cow's rumen—one of the four compartments of its stomach—can digest certain types of the ubiquitous material, representing .

Spatial patterns of gene transcripts captured across single cells of mouse embryo

A new technique called sci-Space, combined with data from other technologies, could lead to four-dimensional atlases of gene expression across diverse cells during embryonic development of mammals.

Global climate dynamics drove the decline of mastodonts and elephants, new study suggests

Elephants and their forebears were pushed into wipeout by waves of extreme global environmental change, rather than overhunting by early humans, according to new research.

How information beyond the genetic sequence is encoded in plant sperm

Hereditary information is passed from parent to offspring in the genetic code, DNA, and epigenetically through chemically induced modifications around the DNA.

Scientists resurrect 'forgotten' genus of algae living in marine animals

In the late 1800s, scientists were stumped by the "yellow cells" they were observing within the tissues of certain temperate marine animals, including sea anemones, corals and jellyfish. Were these cells part of the animal .

Better predicting how plants and animals will weather climate extremes

A team of scientists has devised a more accurate way to predict the effects of climate change on plants and animals—and whether some will survive at all.

Fire ants found to create 'appendages' on self-made rafts when put in water

A team of researchers at the University of Colorado has found that fire ants can create 'appendages' on the rafts they make out of their own bodies when they find themselves in water. In their paper published in the Journal .

Unlocking the power of the microbiome that evolved alongside plants and animals

Not only animals and humans host a complex community of microorganisms—plants do this as well. Researchers at ETH Zurich have recently published two new studies that shed light on fundamental aspects of these close—and .

New approach can add diversity to crop species without breeding GMOs

Breeding better crops through genetic engineering has been possible for decades, but the use of genetically modified plants has been limited by technical challenges and popular controversies. A new approach potentially solves .

Molecular & Computational biology

Scientists risk overestimating numbers of wild bonobos

There might be fewer bonobos left in the wild than we thought. For the last 40 years, scientists have estimated the abundance of endangered bonobos by counting the numbers of sleeping nests left by the apes in forests of .

Multitalented filaments in living cells

The cells that make up our bodies are constantly exposed to a wide variety of mechanical stresses. For example, the heart and lungs have to withstand lifelong expansion and contraction, our skin has to be as resistant to .

Researchers discover Golgi-derived vesicle regulating endosome fission

The endosome has highly dynamic motility and frequently undergoes fission and fusion events to coordinate endocytic trafficking. Endosome fission has been reported to be associated with cargo sorting. After internalization, .

Imaging spectroscopy can predict water stress in wild blueberry fields, says study

Imaging spectroscopy can help predict water stress in wild blueberry barrens, according to a University of Maine-led study.

G-quadruplex-forming DNA molecules enhance enzymatic activity of myoglobin

A collaboration led by Distinguished Professor Dr. Kazunori Ikebukuro from Tokyo University of Agriculture and Technology (TUAT), Japan, discovered that G-quadruplex (G4)-forming DNA binds myoglobin through a parallel-type .

Molecular & Computational biology

Wild bees need diverse agricultural landscapes

Mass-flowering crops such as oilseed rape or faba bean (also known as broad bean) provide valuable sources of food for bees, which, in turn, contribute to the pollination of both the crops and nearby wild plants when they .

Researchers hone in on the best software for detecting microRNAs in plants

Almost twenty years ago, the process of RNA silencing was discovered in plants, whereby small fragments of RNA inactivate a portion of a gene during protein synthesis. These fragments—called microRNAs (abbreviated as miRNAs)—have .


Graduate Study

The program offers work for the degrees master of science and doctor of philosophy in microbiology and for a minor for students majoring in other programs. The interdepartmental microbiology major is offered through faculty housed in twelve departments, including Agronomy Animal Science Biochemistry, Biophysics and Molecular Biology Civil, Construction and Environmental Engineering Entomology Food Science and Human Nutrition Genetics, Developmental and Cell Biology Geological and Atmospheric Sciences Plant Pathology and Microbiology Veterinary Diagnostic and Production Animal Medicine Veterinary Microbiology and Preventive Medicine and Veterinary Pathology. Faculty coordinate graduate education and research in a wide range of topics fundamental to the discipline of microbiology. Specific information about individual faculty and their research areas is available at www.micrograd.iastate.edu.

Prerequisites to graduate study include a sound undergraduate background in chemistry, mathematics and biology, including microbiology and genetics.

Graduates in the Microbiology Graduate program have a broad-based knowledge in the fundamentals of microbiology as well as advanced knowledge in specific areas as determined by their areas of research focus. Students completing the thesis have the technical, research, critical-thinking, problem-solving, and computer skills to design, implement, and conduct research using a variety of current techniques and equipment. They are also able to communicate research results effectively with scientific peer groups in both oral and written formats.


Scope & Mission

Frontiers in Microbiology is a leading journal in its field, publishing rigorously peer-reviewed research across the entire spectrum of microbiology. Field Chief Editor Martin G. Klotz at Washington State University is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, clinicians and the public worldwide.

As we are taking much better account of the unseen majority of life, unravel the biogeochemical processes that microbes facilitate, thereby making planet Earth habitable for all forms of life as we increasingly identify the rules by which microorganisms interact with co-evolving viruses and macroorganisms in health and disease and as we find more and better strategies to mitigate the detrimental effects of anthropogenic activities on the abundance, diversity, distribution and activity of microbial communities, Frontiers in Microbiology will be the 21st century approach to communicate all this progress to both the specialist and a wider audience of readers in the field.

Frontiers in Microbiology is a member of the Committee on Publication Ethics.


Watch the video: PART 3: Modern Microbiology. History of Microbiology. B Pharmacy. Nursing. Medical. Bhushan (December 2022).