Chapter 1 WK2

Helicobacter pylori

spiral shaped bacterium, gram-negative, microaerophilic (needs a small amount of O2), lives in the stomach and duodenum of infected people, can survive the acidity of the stomach, human pathogen

diseases caused by Helicobacterpylori

gastric inflammation and ulceration, increased risk of gastric cancer and tissue lymphoma by 80%, is the second leading cause of cancer-related death in the world

symptoms of H. pylori

some people are asymptomatic, ache or burning in abdomen, nausea, vomiting, frequent burping, bloating, weight loss, goes undetected for a while

transmission H. pylori

natural reserve is the human oral cavity, sheep, 2/3 of the world pop., prevalent among older adults, can be passed person to person through saliva, vomit, or fecal matter, or contaminated food or water.

Virulence factors

traits that enable a microbe to colonize, evade the immune system, and cause disease

H. Pylori virulence factors

urease- catalyzes the hydrolysis of urea, yielding NH3 and CO2-increases the pH to neutral to create a protective bubble, attaches to epithelial lining- causing inflammation, inducing DNA breaks in the epithelial cells that eventually cause mutations leading to cancer cells

Robin Warren

associated H. pylori with ulcers, isolated it and grew it in culture

Barry Marshall

drank the culture, 14 days later showed ulcers in the stomach, won the nobel prize in 2005 because it proved chronic disease can be linked to bacteria

treatment for H.pylori

treated with 10-14 day triple therapy of two antibiotics and a proton pump inhibitor to increase stomach acidity, pump alleviates ulcer related symptoms

Robert Koch

proved that bacillus anthracis causes anthrax

Koch’s postulates

prove that a specific microbe causes a specific disease, find, isolate and grown, inject, same sickness, and reisolate

Franny Hesse

introduced Koch to agar, a gel derived from red algae from Asia

Koch’s postulates applied to tuberculosis

grew TB in coagulated blood serum, injected cells into guinea pigs, died from TB, Koch reisolated TB from dead guinea pigs

limitations of Koch’s postulates

some organisms cannot be grown in pure culture (leprae), using humans in completing the postulates is unethical, molecular and genetic evidence may be used instead, not all pathogens cause disease in all hosts

development of techniques for studying microbial pathogens

Koch’s work led to discovery or development of agar, petri dishes, nutrient broth and nutrient agar, methods of isolating microorganisms, aseptic technique

smallpox

pathogenic virus

Lady Mary Wortley Montagu

inoculating patients with pus from a mild smallpox case to protect them against a more severe case

Edward Jenner

continues the work with cowpox

cowpox

Jenner inoculated a healthy 8-year-old with cowpox, gets mildly sicks, inoculate with smallpox, did not get sick

Vaccination

latin vacca for cow

Pasteur and germ theory

had nothing to do with germ theory

Pasteur showed closely related virus…

that is less virulent can cause the dame immune response in a host leads to protection

Pasteur and Rabies Vaccine

dried spinal tissue to weaken the rabies virus

Joseph Meister

9 year old, received 13 total injections of day 14-1 spinal cord fluid, was the first human vaccine developed after infection

John Snow

1st epidemiologist, 500 died of cholera in 10 days, mapped affected areas, centered on broad street wall-sewer pipe was leaking into well, proposed that cholera was spread through a fecal oral route, convinced officials to remove handle

World Health Organization

tracks global disease

center of disease control and prevention

monitors disease worldwide, domestic public health issues

european centre for disease prevention and control (ECDC)

monitors infectious diseases across the European union

PAN American Health Organization (PAHO)

Regional arm of WHO for americas

Stanley Miller

simulate the spark that might have started forming organic molecules from a mixture of inorganic molecules in a watery environment

Endosymbiotic theory

RNA world hypothesis- store genetic material and catalyze reactions, single lipid layer known as micelle may be an early plasma membrane, primitive cells switched from RNA to DNA

Endosymbiont theory

ancestor of eukaryotic cells engulf mitochondria and/or chloroplast, double membrane, contains ribosomes-produce own proteins, circular DNA, grow independent within the cell

alexander fleming

discovery of penicillin, fungus blew into a plate of staphylococcus aureus, colonies near the fungus developed poorly because it breaks down cell walls

Gnorrhea

one of the most drug resistant disease only 2 antibiotics still work

2050

a rise in infectious diseases as microbes are becoming resistant to our drugs

bacteriology

the study of bacteria

mycology

the study of fungi

virology

the study of viruses

parasitology

the study of protozoa and parasitic worms

immunology

other life-pathogen interaction

1 centimeter

1 cm 10-2 meter

1mm

millimeter 10-3

1 micrometer

um 10-6 meter

1 nanometer

nm 10-9 meter

Leeuwenhoek’s microscope

magnified 300x, single microscope

types of microscopy

light, electon, scanned-probe

light microscopy

a microscope that uses visible light to observe specimens

visible light

travels as an electromagnetic wave (oscillating electric)

electric field

interacts with electrons→changes speed→ a slight delay

refractive index

measures of how greatly a substance slows the velocity of light= higher RI the slower the light travels

refractive indices

how much a light bends through multiple medium

what has a higher refractive index

glass compared to air

focal point

focus light rays at a specific place

focal length

shorter the focal length the higher the magnification

compound microscope

2 lens- objective (4x to 10x) ocular (10x) for total magnification

path of light in light microscope

light ray passes through the specimen and into the objective lens

light microscope resolution

the ability to distinguish in fine detail and structure, shorter wavelengths =higher resolution

compound microscope resolution

0,2 um or 500x better than human eye, van Leeuwenhoek’s microscope has a resolution of 1um

low resolution

waves are too large to penetrate the tighter spaces

Refractive index

is the measure of the light-bending ability in the medium, the more bending with the light the fuzzier the image, add oil for less bending

Brightfield

condenser lens focuses a solid cone of light, light is absorbed, produces a dark image on a bright background of dead, stained specimen

Dark-field microscope

bright subject on dark background, condenser lends focuses a hollow cone of light on the sample, scatters light, good for live, unstained specimen

Phase-contrast

used to observe living, unstained cells, best for transparent specimens, hollow cone of light