IPS/CA2 Microbiology & Parasitology

Robert Hooke

Observed that plant material was composed of 'little boxes' and introduced the term 'cell'.

Anton Van Leeuwenhoek

Using a simple microscope, was the first to observe microorganisms, saw organisms in water, 'Animalcules', and is known as the Father of Bacteriology.

Francisco Redi

Demonstrated that maggots appear on decaying meat only when flies can lay eggs on the meat.

John Needham

Claimed that microorganisms could arise spontaneously from heated nutrient broth.

Lazzaro Spallanzani

Suggested that Needham's results were due to microorganisms in the air entering his broth.

Rudolf Virchow

'Biogenesis' theory.

Louis Pasteur

Demonstrated that microorganisms are in the air everywhere and offered proof of biogenesis through swan-neck flask.

Ignaz Philipp Semmelweis

Proposed that handwashing could prevent the spread of infection (puerperal fever/childbirth fever).

Joseph Lister

Introduced the use of disinfectant to clean surgical dressings to control infections in humans.

Robert Koch

Established experimental steps for directly linking a specific microbe to a specific disease.

Henle-Koch's Postulates

A set of criteria to establish a causative relationship between a microbe and a disease.

Postulate A

All cases of disease should have the organism.

Postulate B

Organism must be isolated from the person and can be grown into pure culture.

Postulate C

Isolated organisms when inoculated, should cause the same disease in a healthy person.

Postulate D

From this healthy person, the organism must be re-isolated.

Edward Jenner

Developed the vaccine for smallpox (Variola) using cowpox (Vaccinia).

Paul Ehrlich

Developed an arsenic-containing chemical called Salvarsan to treat syphilis.

Alexander Fleming

Discovered Penicillin (Penicillium notatum) and noted that bacteria can be eradicated by some fungi.

Ernst Boris Chain & Howard Florey

Developed Penicillin.

Cell

The fundamental structural unit of life.

Cell Theory

1. All organisms are composed of one or more cells. 2. Cells are the smallest living things. 3. Cells arise only by the division of previously existing cells. 4. All organisms living today are descendants of an ancestral cell.

Prokaryotic Cell

'Pre-nucleus' characterized by DNA not enclosed within a membrane, one circular chromosome, lack of membrane-enclosed organelles, and almost always containing peptidoglycan in cell walls.

Nucleoid

Contains genetic material, lacks nuclear membrane and mitotic apparatus, and can have DNA in circular or linear forms.

Plasmid

Small extra piece of chromosome/genetic material that can provide genetic information such as antibiotic resistance and virulence factors.

Cytoplasm

Gel-like matrix of water, enzymes, nutrients, wastes, and gases; site of oxidative and transport processes.

Cell Envelope

Layers that surround the prokaryotic cell, including the S-layer, cytoplasmic membrane, and cell wall.

Cell Wall

Layers of the cell envelope lying between the cell membrane and the capsule, composed mainly of peptidoglycan.

N-acetylglucosamine (NAG)

A component of the backbone made of alternating N-acetylglucosamine and N-acetylmuramic acid.

N-acetylmuramic acid (NAM)

A component of the backbone made of alternating N-acetylglucosamine and N-acetylmuramic acid.

Gram Positive

Bacteria with 40 sheets and a thicker cell wall.

Gram Negative

Bacteria with 1 to 20 sheets and a thinner cell wall.

Teichoic acid

A component that stabilizes the peptidoglycan layer, making up 50% of the dry cell wall and 10% of the bacterial weight.

Lipoproteins

The most abundant protein of Gram (-) bacteria, stabilizing the outer membrane and anchoring it to the peptidoglycan layer.

Lipopolysaccharide (LPS)

Consists of a polysaccharide core (O-antigen) and a Lipid-A, acting as an endotoxin of Gram (-) bacteria.

Periplasmic Space

The space between the inner and outer membrane, occupying 20-40% of the cell volume.

Capsule

Extracellular polymers forming a well-defined layer surrounding the cell, contributing to bacterial pathogenicity and protection against bacteriophages and phagocytosis.

Glycocalyx

Made up of polysaccharides, contributing to bacterial adherence.

Flagella

Threadlike appendages used for locomotion, contributing to bacterial pathogenicity (H-antigen).

Motile

Organisms that have flagella and can move.

Sessile

Non-motile organisms without flagella and no locomotion.

Atrichous

Bacteria with no flagellum.

Monotrichous

Bacteria with a single polar flagellum.

Amphitrichous

Bacteria with a single or clusters of flagella at both poles.

Lophotrichous

Bacteria with a single tuft or cluster of flagella at one pole.

Bilophotrichous

Bacteria with two tufts or clusters of flagella at both poles.

Peritrichous

Bacteria with flagella randomly distributed around the cell.

Pili/Fimbriae

Rigid appendages shorter and finer than flagella, made of pilins, used for attachment and conjugation.

Endospores

Non-reproductive structures that are highly resistant to desiccation, heat, and chemical agents.

Transformation

A method of DNA transfer where genes are transferred as 'naked' DNA in solution.

Conjugation

A method of DNA transfer involving direct cell-to-cell contact.

Transduction

A method of DNA transfer where DNA is transferred by a bacteriophage.

Transposition

A method of DNA transfer where DNA fragments are cut and pasted within the genome.

Eukaryotic Cell

'True nucleus' cells with several membrane-enclosed organelles.

Cell Wall Composition of Algae

Composed of cellulose.

Cell Wall Composition of Fungi

Composed of chitin, a polymer of N-acetylglucosamine (NAG).

Cell Wall Composition of Yeast

Contains polysaccharides mannan and glucan.

Cell Wall Composition of Protozoa

Does not have a cell wall; instead, it has a flexible outer covering called a pellicle.

Cytoplasmic Streaming

Movement of cytoplasm from one part of the cell to another.

Nucleus

The largest organelle in the cell, containing chromatin (DNA) and serving as the control center for cell metabolism and reproduction.

Endoplasmic Reticulum (ER)

An extensive network of membranes, with Rough ER containing ribosomes and Smooth ER lacking ribosomes.

Smooth ER

Lacks ribosomes.

Ribosomes

Site of protein synthesis.

70S ribosomes

Found in bacteria and archaebacteria (composed of small 30S and large 50S subunits).

80S ribosomes

Found in eukaryotes (composed of small 40S and large 60S subunits).

Golgi Apparatus

Sorts proteins made by the ribosomes.

Lysosomes

Filled with digestive enzymes to remove waste and invading bacteria.

Vacuoles

Space or cavity in the cytoplasm enclosed by a membrane.

Mitochondria

Spherical or rod-shaped, 'powerhouse of the cell'.

Chloroplasts

Captures light energy and converts it into chemical energy.

Chlorophyll

A green pigment inside the chloroplast.

Disease

a pathological condition of body parts or tissues characterized by an identifiable group of signs and symptoms​

Sign

objective, health issue that can be observed​

Symptom

subjective experience of a potential health issue​

Infection

invasion or colonization of the body by pathogenic microorganisms

Syndrome

Combined signs and symptoms

Communicable Disease

a disease that is transmissible from one person to another​

Non-communicable Disease

Disease that is not spread from one host to another

Prevalence

the fraction of the population having the disease at a specified time​

Incidence

the fraction of the population that contracts the disease during a particular period

Sporadic Disease

occurs occasionally within the population of a particular geographic area​

Endemic Disease

always present within a population of a particular geographic area​

Epidemic Disease

usually occurs within a relatively short period and affecting a bigger number of the population​

Pandemic Disease

occurs in many countries simultaneously—sometimes worldwide

Acute Disease

develops rapidly but lasts only a short time​

Chronic Disease

develops more slowly, it is less severe and may be recurrent for long periods​

Latent Disease

remains inactive for a time but then becomes active to produce the symptoms

Local Infection

invading MO are limited to a relatively small area of the body​

Systemic Infection

invading MO are spread throughout the body​

Focal Infection

local infection that later develops into a systemic infection

Incubation Period

time between the arrival of the pathogen and the onset of symptoms​

Prodromal Period

short period characterized by early mild symptoms of disease such as general aches​

Period of Illness

disease is most acute, patient experiences typical symptoms of the disease​

Period of Decline

signs and symptoms of the disease subside, the patient is vulnerable to secondary infection​

Period of Convalescence

period of recovery, patient regains strength

Innate Immunity

Inborn, natural immunity, nonspecific, different barriers in the body

Acquired Immunity

Immunity developed after exposure to an antigen

Antibody-Mediated

Aka Humoral Response

Cell-Mediated

Aka Cellular Response

Intracellular antigens

Antigens located within the cells.

Origin of Cells

Stem cells in the bone marrow of adults and liver of infants.