BSc Botany 3rd Year Microbiology & Plant Pathology Notes 2024.All of these developments occurred in Europe. Not until the early 1900s did microbiology become established in America. Many microbiologists who worked in America at this time had studied either under Koch or at the Pasteur Institute in Paris. Once established in America, microbiology flourished, especially with regard to such related disciplines as biochemistry and genetics. In 1923 American bacteriologist David Bergey established that science’s primary reference, updated editions of which continue to be used today. BSc Botany 3rd Year Microbiology & Plant Pathology Notes 2024.
Microbiology
Microbiology is the study of microscopic organisms, such as bacteria, viruses, archaea, fungi and protozoa. This discipline includes fundamental research on the biochemistry, physiology, cell biology, ecology, evolution and clinical aspects of microorganisms, including the host response to these agents.
What are the 5 branches of microbiology?
- Bacteriology: the study of bacteria.
- Immunology: the study of the immune system.
- Mycology: the study of fungi, such as yeasts and molds.
- Nematology: the study of nematodes (roundworms).
- Parasitology: the study of parasites.
- Phycology: the study of algae.
microbiology
Spontaneous generation versus biotic generation of life
The early Greeks believ that living things could originate from nonliving matter (abiogenesis) and that the goddess Gea could create life from stones. Aristotle discard this notion, but he still held that animals could arise spontaneously from dissimilar organisms or from soil. Uncover the potential of technology in the field of microbiological researchHear a scientist discuss the potential for interdisciplinary research in microbiology, biochemistry, and chemistry.University College Cork, Ireland (A Britannica Publishing Partner)See all videos for this article. BSc Botany 3rd Year Microbiology & Plant Pathology Notes .
Microbes and disease
Girolamo Fracastoro, an Italian scholar, advanc the notion as early as the mid-1500s that contagion is an infection that passes from one thing to another. A description of precisely what is pass along elude discovery until the late 1800s, when the work of many scientists, Pasteur foremost among them, determin the role of bacteria in fermentation and disease. Robert Koch, a German physician, defin the procedure (Koch’s postulates) for proving that a specific organism causes a specific disease.
Progress in the 20th century
All of these developments occurr in Europe. Not until the early 1900s did microbiology become establish in America. Many microbiologists who work in America at this time had studi either under Koch or at the Pasteur Institute in Paris. Once establish in America, microbiology flourish, especially with regard to such relat disciplines as biochemistry and genetics. In 1923 American bacteriologist David Bergey establish that science’s primary reference, editions of which continue to use today.
The major groups of microorganisms—namely bacteria, archaea, fungi (yeasts and molds), algae, protozoa, and viruses—are summarize below. Links to the more detail articles on each of the major groups are provid.
The study of microorganisms has also advance the knowledge of all living things. Uncover the potential of technology in the field of microbiological researchHear a scientist discuss the potential for interdisciplinary research in microbiology, biochemistry, and chemistry.University College Cork, Ireland (A Britannica Publishing Partner)See all videos for this article. BSc Botany 3rd Year Microbiology & Plant Pathology Notes . This intensive probing into the functions of microbes has resulte in numerous and often unexpecte dividends. Knowledge of the basic metabolism and nutritional requirements of a pathogen, for example, often leads to a means of controlling disease or infection.
Types of microorganisms
The major groups of microorganisms—namely bacteria, archaea, fungi (yeasts and molds), algae, protozoa, and viruses—are summarize below. Links to the more detail articles on each of the major groups are provid.
Bacteria (eubacteria and archaea)
Microbiology came into being largely through studies of bacteria. Unlike algae, fungi do not contain chlorophyll and thus cannot carry out photosynthesis. Fungi do not ingest food but must absorb dissolved nutrients from the environment. Of the fungi classified as microorganisms, those that are multicellular and produce filamentous, microscopic structures are frequently called molds, whereas yeasts are unicellular fungi.
The organisms that constitute the microbial world are characterize as either prokaryotes or eukaryotes; all bacteria are prokaryotic—that is, single-cell organisms without a membrane-bound nucleus. Their DNA (the genetic material of the cell), instead of being in the nucleus, exists as a long, thread with no specific location within the cell.
BSc Botany 3rd Year Microbiology & Plant Pathology Notes
Until the late 1970s it was generally accept that all bacteria are closely relate in evolutionary development. This concept was challenge in 1977 by Carl R. Bacteria have a variety of shapes, including spheres, rods, and spirals. Individual cells generally range in width from 0.5 to 5 micrometres (μm; millionths of a metre). Although unicellular, bacteria often appear in pairs, chains, tetrads (groups of four), or clusters. Some have flagella, external whiplike structures that propel the organism through liquid media; some have capsule, an external coating of the cell; some produce spores—reproductive bodies that function much as seeds do among plants. One of the major characteristics of bacteria is their reaction to the Gram stain. Depending upon the chemical and structural composition of the cell wall, some bacteria are gram-positive, taking on the stain’s purple colour, whereas others are gram-negative.
Today the are simply as the true bacteria (or the bacteria) and form the Bacteria. The evolutionary relationships between various members of these three groups, however, have become uncertain, as comparisons between the DNA sequences of various microbes have reveale many puzzling similarities. As a result, the precise ancestry of today’s microbes is very difficult to resolve. Even traits thought to characteristic of distinct taxonomic groups have unexpectedly been obser in other microbes. For example, an anaerobic ammonia-oxidizer—the “missing link” in the global nitrogen cycle—was isolate for the first time in 1999. This bacterium (an aberrant member of the order Planctomycetales) found to have internal structures similar to , a cell with archaean traits, and a form of reproduction (budding) similar to that of yeast cells.
BSc Botany 3rd Year Microbiology & Plant Pathology Notes
Bacteria have a variety of shapes, including spheres, rods, and spirals. Individual cells generally range in width from 0.5 to 5 micrometres (μm; millionths of a metre). Although unicellular, bacteria often appear in pairs, chains, tetrads (groups of four), or clusters. Some have flagella, external whiplike structures that propel the organism through liquid media; some have capsule, an external coating of the cell; some produce spores—reproductive bodies that function much as seeds do among plants. One of the major characteristics of bacteria is their reaction to the Gram stain. Depending upon the chemical and structural composition of the cell wall, some bacteria are gram-positive, taking on the stain’s purple colour, whereas others are gram-negative.
Through a microscope the archaea look much like bacteria, but there are important differences in their chemical composition, biochemical activities, and environments. The cell walls of all true bacteria contain the chemical substance peptidoglycan, whereas the cell walls of archaeans lack this substance. Many archaeans are noted for their ability to survive unusually harsh surroundings, such as high levels of salt or acid or high temperatures. These microbes, called extremophiles, live in such places as salt flats, thermal pools, and deep-sea vents. Some are capable of a unique chemical activity—the production of methane gas from carbon dioxide and hydrogen. Methane-producing archaea live only in environments with no oxygen, such as swamp mud or the intestines of ruminants such as cattle and sheep. Collectively, this group of microorganisms exhibits tremendous diversity in the chemical changes that it brings to its environments.
Algae
The cells of eukaryotic microbes are similar to plant and animal cells in that their DNA is enclosed within a nuclear membrane, forming the nucleus. Eukaryotic microorganisms include algae, protozoa, and fungi. Collectively algae, protozoa, and some lower fungi are frequently referred to as protists (kingdom Protista, also called Protoctista); some are unicellular and others are multicellular.
Unlike bacteria, algae are eukaryotes and, like plants, contain the green pigment chlorophyll, carry out photosynthesis, and have rigid cell walls. They normally occur in moist soil and aquatic environments. These eukaryotes may be unicellular and microscopic in size or multicellular and up to 120 metres (nearly 400 feet) in length. Algae as a group also exhibit a variety of shapes. Single-celled species may be spherical, rod-shaped, club-shaped, or spindle-shaped. Some are motile. Algae that are multicellular appear in a variety of forms and degrees of complexity. Some are organized as filaments of cells attached end to end; in some species these filaments intertwine into macroscopic, plantlike bodies. Algae also occur in colonies, some of which are simple aggregations of single cells, while others contain different cell types with special functions.
Fungi
Fungi are eukaryotic organisms that, like algae, have rigid cell walls and may be either unicellular or multicellular. Some may be microscopic in size, while others form much larger structures, such as mushrooms and bracket fungi that grow in soil or on damp logs. Unlike algae, fungi do not contain chlorophyll and thus cannot carry out photosynthesis. Fungi do not ingest food but must absorb dissolved nutrients from the environment. Of the fungi classified as microorganisms, those that are multicellular and produce filamentous, microscopic structures are frequently called molds, whereas yeasts are unicellular fungi.
In molds cells are cylindrical in shape and are attached end to end to form threadlike filaments (hyphae) that may bear spores. Individually, hyphae are microscopic in size. However, when large numbers of hyphae accumulate—for example, on a slice of bread or fruit jelly—they form a fuzzy mass called a mycelium that is visible to the naked eye.