LECTURE 1

Classification of Microbes

1.      presence or absence of cell

2.      disease-causing or not disease-causing

Cellular

Microorganisms that contain a cell, such as bacteria, archaea, fungi, and protists.

Acellular

Lifeless microorganisms like viruses, viroids, and prions that do not have a cell and depend on a host for chemical reactions.

Pathogen

Microorganism causing disease, like Staphylococcus aureus.

Non-Pathogen

Microorganism not causing disease, like Staphylococcus epidermidis.

Indigenous Microbiota

Native microorganisms aiding in digestion and protecting against disease.

Opportunistic Pathogens

Indigenous microorganisms becoming pathogenic under certain conditions.

Photosynthetic Bacteria

Microorganisms like Cyanobacteria producing oxygen and food.

Decomposition

Microorganisms breaking down dead materials into simpler forms.

Bioremediation

Microorganisms helping eliminate harmful events like oil spills.

Elemental Cycle

Microorganisms replenishing elements in cycles like carbon, oxygen, nitrogen, and sulfur.

Planktons

Microorganisms serving as food in marine ecosystems.

Digestion

Microorganisms aiding in breaking down cellulose in termites.

Food and Beverages

cheese and alcohol and products of fermentation

Antibiotics

Substances curing infections and developing immunity.

Genetic Engineering

Using microorganisms in technological advancements like insulin production.

Cell Model

Microorganisms, especially prokaryotes, serving as cell models.

Diseases

pathogenic and non-pathogenic microorganisms.

-        a German botanist and German physiologist who proposed the Cell Theory in 1839

-        studied plants and studied animals, and in the process, they both noticed “tiny dots” in the middle of the cells that they observed under the microscope, which were later called as nuclei, and both concluded that it must be a important part to all life

Cell Theory has three parts:

(1)  all organisms are made of cells,

(2)  cells are the basic units of life, and

(3)  cells come from preexisting cells that have multiplied, as described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells)

Thomas Henry Huxley

-        proposed a Mechanistic Model (cells are little factories with different parts that have different functions; their functions make the parts add up into an organic whole)

-        wrote the cell theory along with Matthias Schleiden and Theodor Schwann

Anton Van Leeuwenhoek

-        not a trained scientist and was only fascinated with placing lens on metal for observation

-        the first one to see microorganisms and called them as “animalcules” since they resembled small animals

Louis Pasteur

-        credited as the co-founder of microbiology and the founder of modern zymology (science of fermentation)

-        disproved abiogenesis through his milk experiment and introduced biogenesis

-        in his milk experiment, wherein there were two containers of milk, one with no lid and the other covered, microorganisms only grew on the milk that was uncovered

-        Pasteurization became accepted as form of preservation and is a process of exposing a certain liquid such as milk to prevent the growth of bacteria

-        he gave birth to the concept of fermentation because according to him, grape with yeast can produce alcohol

Abiogenesis

Spontaneous generation theory.

Biogenesis

Life from life theory.

Joseph Lister

-        a British surgeon who established the study of antisepsis

-        applying Louis Pasteur's germ theory of fermentation on wound putrefaction, he advocated for hospital practices such as sterilization in surgery using carbolic acid (phenol) as an antiseptic

Robert Koch

Scientist contributing to bacteriology and identifying disease postulates.

Julius Petri

-        proposed the petri dish to Koch for culturing of microorganisms

Robert Hesse

agar

John Snow

-        during the cholera outbreak that ravaged England in 1854, he convinced the Soho council to remove the well pump handle due to a personal belief that the germ known as Vibrio cholerae responsible for causing the disease was present in its water

-        cholera cases gradually dropped after the well pump handle was removed but later, it was found out that the well did not directly cause cholera and the decrease in cases were a mere coincidence

Jacques Loeb

-        a German-American physiologist who began experiments on embryonic development (how organisms grow from single-celled embryos)

-        introduced parthenogenesis through sea urchins (birth from self) and it was seen as an early form of bioengineering

-        his notable students included the behavioral psychologists, Burrhus Frederic Skinner and John Broadus Watson, along Gregory Pincus, one of the creators of the birth control pill

Miasma Theory

Theory attributing diseases to foul-smelling airs from decaying matter.