Wednesday, June 27, 2012

Careers

from masteringmicrobology website: http://www.masteringmicrobiology.com/ 

Careers


Exploring Careers in Microbiology If you're like many microbiology students, you may be taking this course because it's required for nursing, dental hygiene, or another health career program. While taking the course, you may well have discovered that you enjoy problem-solving and working in the lab, and that you are fascinated by science. A person who works in the microbial sciences, a microbiologist, can specialize in general, environmental, food, agricultural, or industrial work, just to name a few areas. Microbiologists study a wide variety of microscopic organisms in order to learn how they reproduce, grow, and interact with their environment. This page will introduce you to some career opportunities in the fast-growing field of microbiology. You may come across some occupations that you did not know existed or professions that you never even considered before today.
In general, careers in microbiology can be grouped into three categories:
Basic research to establish factual information upon which more applied research can be based.
Applied research to discover cures and treatments or develop products.
Health professions which make use of both basic and applied research to help people and animals
Careers in Basic Research
The purpose of basic research is to advance fundamental knowledge and understanding of science and scientific processes. Basic research may often lead to the development of new scientific theories and practical applications.
Mycologists, sometimes called "the first microbiologists," study the relationship of fungi to the environment and can be found in clinical laboratories, breweries, cheese-making facilities, or out in the fields and forests.
Virologists are often prominent in today's news because of their work with viral-related diseases such as Avian Flu and SARS. They work with microorganisms so small that if people were the size of viruses, the world's population would fit on the head of a pencil eraser!
Marine microbiologists study viruses, bacteria, fungi, protozoa, and algae that live in the planet’s oceans. Some scientists may simply study microbial diversity and strive to characterize marine microorganisms. Other research groups are gathering information that may lead to new biotechnological and pharmacological developments such as antibiotics or anti-cancer drugs.
Biotechnologists/industrial microbiologists, including microbial geneticists and molecular biologists, work on the frontlines or research, with a wide range of opportunities in research and development programs, product design and testing, and the development of new diagnostic products or procedures.
Microbial ecologists study how microorganisms exist and interact with each other in their natural environment. Their work is important and insatiable due to the fact that less than 1% of all the microbial species on Earth are known. There are numerous opportunities in microbial ecology covering a wide range of topics, including, but not limited to, bioremediation, evolution, and biodiversity.
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Careers in Applied Research
The objective of applied research is to solve problems in such areas as human health, agriculture, energy, etc. Those working in this field may pursue the development of medically important cures, treatments, and other products. Medical technology has been described as "the frontier of scientific medicine," a world of exacting precision and exciting discoveries. Clinical laboratory testing is key to the detection, diagnosis, and treatment of disease. Requiring knowledge, skill, and speed, the medical technologist is asked to perform a variety of tests on various body fluids and cells looking for parasites, bacteria, and other microorganisms.
Medical technologists can work in clinical or research environments, for public or private health agencies, or for pharmaceutical companies. Within the broad field of medical technology are numerous professions, with varying requirements for education and expertise. Medical technologists can also choose from a number of subspecialties. Cytotechnologists specialize in the study of cells, while the histologic technician concentrates on body tissues. Specialists in blood banking technology are trained in advanced blood techniques, such as sophisticated blood typing, collection, and transfusions. Immunology technicians investigate diseases that affect the immune system and develop treatments and vaccines.
Two other related job descriptions, which are often stepping stones to becoming a medical technologist (but which are satisfying careers themselves), are the clinical laboratory technologist and the clinical laboratory technician.
At the beginning level, the clinical laboratory technician performs routine laboratory procedures, such as collecting blood specimens, sample preparation, and staining slides for microorganisms. Technicians are usually supervised by medical technologists or laboratory managers. The clinical laboratory technologist performs more complex procedures but does not undertake the supervisory and educational responsibilities of medical technologists. With less rigorous education and on-the-job experience requirements, these positions can be found in all laboratories.
Parasites are viruses, bacteria, protistis, worms, insects and any other microorganisms that use other living organisms in order to survive. Parasitologists work in human medicine, public health, veterinary medicine, and research labs studying the complex and sometimes harmful interaction that parasites have with their hosts.
Agricultural scientists are responsible for identifying ways to improve and monitor both the quality and yield of agricultural products. Scientists may strive to make improvements in the production of livestock, the growth of crops for human consumption, the growth and preparation of crops for animal feed, and the quality of the soil and/or pasture used to sustain these products.
Food safety technologists investigate the chemical, physical, and biological nature of food. This knowledge is applied to processing, preserving, packaging, distributing, and storing an adequate, nutritious, wholesome, and economical food supply.
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Careers as Health Professionals
Health professionals make use of both basic and applied research to help people and animals. The knowledge and skills required in this field are diverse and extremely important.
Respiratory therapists and respiratory therapy technicians treat patients with heart-lung problems by administering oxygen, various types of gases or aerosol drugs. They may also do diagnostic testing related to respiratory function.
Nursing is another career that can be pursued on several levels, in hospitals, clinics, or doctors' offices. Responsibilities of the registered nurse (RN) often include diagnostic, patient-training, and supervisory duties, requiring completion of a BSN (Bachelor of Science in Nursing) or ADN (Associate Degree in Nursing) program. Licensed vocational nurses (LVN) and licensed practical nurses (LPN) complete one-year diploma programs and perform less technical nursing functions, such as general care for the sick or injured, under supervision of RNs.
Did you know that in this era of preventive dentistry, the dental hygienist serves an increasingly important function? These individuals add patient assessment and evaluation, as well as instruction in self-care, to dental hygiene treatment procedures.
The profession of physician's assistant (PA) is one of the fastest growing occupations in the medical community. Physician's assistants work under a physician's supervision and are formally trained to perform examinations, give treatments, counsel patients, and interpret laboratory tests.
People today are traveling now more than ever and the world has evolved into a global community of culture, commerce, and, sometimes, disease. Infectious disease scientists (IDS) research the interaction between humans and microbes and strive to characterize, track, and eventually prevent infections. ID scientists also research new treatments and/or cures for various infectious diseases, including HIV/AIDS, hepatitis, West Nile Virus, antibiotic-resistant bacteria, and influenza, just to name a few.
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More Career Options
Microbiologists with special interests will find rewarding careers by specializing in agricultural, industrial, aquatic, or even space microbiology.
For those whose interests lie outside the laboratory, a science education can be put to good use in such professions as medical illustrator, medical photographer, and medical or science writer, who combine their love of science with other specialized skills to assist research scientists, physicians, and medical educators.
If you are business-minded, like to travel, and enjoy interacting with people, a background in microbiology can also lead to a job as a sales representative for medical or pharmaceutical companies.
For more information, you may want to consult the "Health Career Guidebook" published by the U.S. Department of Labor and U.S. Department of Health and Human Services, available at most public libraries.

Emerging diseases websites

from http://www.masteringmicrobiology.com/


Avian influenza – situation in Egypt – update
06/07/2012
The Ministry of Health and Population of Egypt has notified WHO of a new case of human infection with avian influenza A(H5N1) virus.
Avian influenza - situation in China, Hong Kong Special Administrative Region (Hong Kong, SAR) - update
06/05/2012
The Centre for Health Protection of the Department of Health, Hong Kong, China, has reported a human case of avian influenza A(H5N1) virus infection.‪ The case is a 2 year-old male from Guangzhou City, Guangdong province. He developed symptoms on 23 May 2012 in Guangdong province and went to a private clinic in Hong Kong, China, on 26 May 2012. He developed febrile convulsion and was transferred to a hospital on 28 May 2012 and was laboratory confirmed as A(H5N1) on 2 June 2012. His condition remains serious and he remains hospitalized.
Avian influenza – situation in Cambodia – update
05/29/2012
The Ministry of Health (MoH) of the Kingdom of Cambodia has announced a confirmed case of human infection with avian influenza A (H5N1) virus.
Meningococcal disease: situation in the African Meningitis Belt
05/24/2012
From 1 January to 17 April 2012 (epidemiologic week 17), outbreaks of meningococcal disease have been reported in 42 districts in 10 of the 14 countries of the African Meningitis Belt 1. These outbreaks have been detected as part of the enhanced surveillance.
Avian influenza – situation in Indonesia – update
05/02/2012
The Indonesian IHR National Focal Point of the Ministry of Health has notified WHO of a new case of human infection with avian influenza A(H5N1) virus.

6_28 Lecture notes: Virus

Review Bacterial growth curve chart (fig 6.21)



A. bacteria do not reproduce because they are adapting to new environment = lag phase

B. Exponential growth phase - when number of cells are doubling and doubling, etc.

C. MAXIMUM Stationary phase (carrying capacity)

D. Death phase (some cells remain viable): two options

1. Crash: all cells die


 2. Minimum Stationary Stage: A few hardy cells remain
       -(carriers, typhoid Mary: gall bladder colonized: no symptoms but passed to other through infected fecal matter; strep throat and removal of tonsils) 


Viruses and viral Anatomy

human skin cell with herpes virus (required to reproduce inside another cell)

virus infect bacteria and most of the information we know about viruses was done upon bacteria
---
Table 12. 2 families of human viruses

Fig. 13.4

size of viruses are very small
--









 What are Viruses?
  •  Non-reproducing, non metabolizing "particles"
  • Floating free = VIRION (not a virus, because it is not INSIDE a cell) 
  • Obligate intracellular parasites
  • Eukaryotic host cells: 
    • 1. naked - basic (unenveloped)
    • 2, Enveloped = luxury model
Infect Prokaryotic host cells:
        3 - Bacteriophages (phages)
        - Viruses that infect bacteria
Fig. 13. 6

Standard Parts of ALL viruses:
  • Genetic material: 4 options
    • single stranded DNA
    • single stranded RNA
    • Double Stranded DNA
      • double stranded RNA
    • Protein capsid (shell) 
      • composed of capsomere proteins
    • Shell + genome = nucleocapsid
    •  Fig. 13. 1

Complex viruses: Enveloped (fig. 13.7) 
  •  Envelope: phospholipid bilayer (membrane from last host) 
    • vulnerable outside body, but more protected and less likely to be recognized as foreign by immune system
    • glycoprotein spikes = peplomers
    •   ___________or matrix (glue that holds plasid to envelope)
---
  • Other Optional Parts: 
    • unique enzymes;
      • Reverse transcriptase - DNA from RNA template (retroviruses) (ex: HIV) 
      •  Protease - cuts viral protein
      • Integrase- joins viral genes to host genome (ex. Herpes, HIV1)---
----Break ---


If you strip off envelope the virus is NOT a functional naked virus, its always one way or another....

 Structure of AIDS Virus (fig 25. 16)
  • Peplomers
  • matrix
  • capsid
  • genome
  • enzymes


Bacteriophage: Complex  capsid divided into:  Fig. 13.6
* complex capsid:
  • head
  • tail
  • tail fibers on baseplate
  • unique enzyme- lysozyme on baseplate: digest peptidogycan





Viral Replication:
If use Lytic cycle – called VIRULENT virus: immediate

If use Lysogenic cycle – called Temperate virus: may be delayed

Chicken pox vaccine: live attenuated virus might cause shingles? 
******

Lytic life cycle:  Fig. 13.8
Step 1: Attachment / Adhesion
 
Receptor proteins on host cell surface (specificity)
virus binds by ligand proteins:
Phage:tail fibers
Naked:capsomeres
Enveloped:peplomers

*drug target: attachment antagonists
********* group activity*********


* Label diagram:
A. peplomer
B. envelope (made from a cell membrane)
C. capsid
d. Capsomeres
e. genome

* cde = nucleocapsid
* which of the lettered parts would b the ligand for the host cell surface proteins? A = peplomer
* not transmitted to water because enveloped so vulnerable outside body


****** print out sheet for after exam*****


Web Resources

Microbiology on the Web

links from:

http://www.masteringmicrobiology.com/ 

 

Note: The links on this page may unexpectedly expire due to the dynamic nature of the Internet. While we make every effort to catch dead links, we would appreciate your help. If you find that a link on this page has expired, please notify our maintenance team. Thank you!
The American Society for Microbiology
ASM is the world's largest scientific society of individuals interested in the microbiological sciences. The Society's mission is to advance microbiological sciences through the pursuit of scientific knowledge and dissemination of the results of fundamental and applied research.
World Health Organization
Provides fact sheets, including epidemiological data, on an extensive list of diseases.
NIH Division of Microbiology and Infectious Disease
Includes information on the many diverse research areas of the DMID division of the National Institutes of Health, ranging from basic bacteriology through vaccine development.
MicrobeLibrary.Org
Provided by the American Society for Microbiology, this site includes access to over 150 images (such as organisms and stains) submitted by microbiologists. Also includes curriculum resources and the online Microbiology Education Journal.
Genomes to Life
Learn how the U.S. Department of Energy is using microbial genomics to develop new energy and environmental technologies. Includes educational image galleries covering biofuels, systems biology, and basic genomics.
The Microbiology Information Portal
A microbiology information portal containing a vast collection of resources including articles, news, frequently asked questions, and links pertaining to the field of microbiology.
Access Excellence: Graphics Gallery
This graphics gallery from Genentech's Access Excellence site includes illustrations of DNA structure, replication, RNA synthesis and processing, the lac operon, and more.
Nutrition and Growth of Bacteria
You can learn more about the physical and chemical requirements for microbial growth at this site from the University of Wisconsin, Department of Bacteriology.
National Library of Medicine
The NLM, located at the National Institutes of Health in Bethesda, Maryland, is the world's largest medical library. This website provides an extensive collection of information on research, medicine and healthcare.
The Bad Bug Book
Provides basic facts regarding foodborne pathogenic microorganisms and natural toxins.
Microbes in Sickness and in Health
Download a PDF to learn more about how microbes interact with humans, both in sickness and in health.
AIDS Education Global Information System
In 2006 alone, the World Health Organization estimated that 37.2 million adults and 2.3 million children were living with HIV. This website features valuable HIV/AIDS information and news.
Vaccine Information
Information and studies on currently available vaccines, as well as the benefits and potential risks of vaccination.
Food Safety
The continuing project to reduce the impact of foodborne illnesses in the world by the Food Safety Department of WHO.
Scientific American Online
"Today's News" and "Feature Articles" frequently include topics related to microbiology.
Science Daily
Contains links to science research articles, updated daily.
From Dr. Maxwell's Blackboard weblinks: 

  • This site to accompany the 3rd edition of the Bauman text includes so much....a version of the entire book electronically (eBook), animations, tests, images, and other resources.  Take advantage of it if you purchased the text!
  • This website (accessed through code in the front of the book) has great resources, including the animations shown in class.
  • This website has a lot of helpful sections, expecially on Viral life cycle stages (unit 3, which includes viruses, then Roman numeral IV has parts A-K on viruses, then you can click on the F (Animal virus life cycles) or G (Bacteriophage life cycles), and the animations are embedded as links within the text).  For horizontal gene transfer (Topic I, then section G) there are descriptions for all of the recombination types, and great animations as well.  Go to the "Table of Contents" at the top of the page for other sections of interest. ALSO RECOMMENDED are the sections on HIV life cycle, immunology and Level 2 and 3 defense.
    Here is the URL in case the link does not work:
    http://student.ccbcmd.edu/courses/bio141/lecguide/index.html
  • This is actual time-lapse photography showing how the cell uses chemotaxis to follow bacteria around by extending pseudopods in the direction of the bacteria.  Cute!
  • This animation shows WBC finding bacteria, phagocytizing them, and then alerting the body about the invading pathogen by secreting "wake-up" chemicals called cytokines.
  • Wow!  Amazing sliding scale to let you look at how the sizes of human cells, bacterial cells, viruses, molecules, and much more compare to one another.  This is especially helpful as you think about how various of the body's defenses can defend against pathogens.
  • This is a great site, from the CDC, which discusses vaccine safety.  It includes common myths, studies and data on the facts, and links to other sites.  You can click on topics of concern, like "autism" and get the results of their exhaustive search for information.
  • This YouTube video (shown in class) is GREAT! 
  • This page is a great overall Influenza resource.
  • This goes a little more in-depth than we do in class, but it's really interesting!
  • This site would be the most reliable about the outbreak, since they are one of the main facilities that do the identification and tracking of pandemics.
  • This will reflect any new verified outbreaks and/or deaths, as well as talking about swine flu in general in the "background" part.
  • Great for facts on all of the important bioterrorism organisms, including smallpox and anthrax.  Follow the vaccination link to see vaccination pictures and adverse reactions to vaccination pictures.

6_25 Class notes


Group Activity #1
Your company picnic was this past Saturday afternoon and a good time was had by all. Unfortunately, later Sat night several employees were feeling ill, with symptoms of nausea, vomiting, and diarrhea.
You are charged with determining how they got sick.

You consider: Symptoms, timing of symptoms, handling

Stephylococeus Aureus
Samonella  4 hrs – 2 days (vomiting)
Menu: Sweet Tea, grilled chicken, potato salad (mayniose, eggs), watermelon

We believe the pathogen is Samonella because the incubation period is 4 hours to 2 days and the source would be the uncooked or undercook chicken that may have been improperly handled. The symptoms and timing align: less than one day, nausea, vomiting and diarrhea.

Kristen Bazemore
Harsimran Ahluwalia (Simran)

Which food was the cause?
Potato salad (Staphylococcus)
Clues: timing short, no fever seen
Cause: handled AFTER ingredients cooked, moist, no gloves worn (or preparer sneezed)
*food allowed to sit out at warm temperature…. 2 ½ hours starts when eggs cooked
* Grilled chicken: Salmonella, cross contamination (fever and longer incubation period)
* Sweet tea: E. coli, Hepatitis A, preparer not washing hands after using restroom
* Watermelon: E. Coli, Cholera, Salmonella, Hepatitis A, runoff from nearby farm (wash the outside of the melon)
Robert Hooke: British scientist mid 1600, looked at cork, published book “micrographic”
He did not see any bacteria, called them cells and got people interested in microscopy
Anton van Leeuwenhoek (1632-1723) Fig 1.1 (has microscope in hand, very little) not scientist, rich merchant, import/export. Thread count on sheets, fabric, made own magnifying lens. 300 x 2 plates of brass.
Hooke helped publish drawings (Royal Society of London, only scientific publication 1673-1723) of Leeuwenhoek…. Late 1600 until death early 1700s
·         Viewed pond water, feces, tooth scrapings, semen, etc.
·         First person to see and described:
o   Bacteria- all three basic shapes  (example picture and movement of bacteria)
o   Protozoa
o   Sperm and semen (drawing of sperm he saw with immature baby, humocoulos?)
o   Red blood cells
o   Capillaries
o   Didn’t connect to diseases
o   His microscope was better than everyone else’s but others couldn’t see them
·         No further microscopy discoveries after his death (1723) for over 100 years!
o   Why? Secretive, scope technology lagged
o   Never took an apprentice and did not let Czar or Queen to touch it
o   No one thought it was important
o   “Animacules” not significant in disease or food spoilage
·         Meanwhile, Controversy Sparked debate and experimentation
o   Spontaneous generation
o   Theories of disease
Spontaneous generation: living creatures arise from nonliving components:
Example: eels from mud, maggots from rotting foods, fleas from sweaty cloth
Theories of Disease:
                Hypothesis: Curses by witches
·         Inheritance (they thought tubercolus was)
·         Punishment for sins (example AIDS virus)
·         Miasma- gases of fumes rising from diseased or dead individuals
·         Germs (later)
Miasma: plague cart, plague pole, distance of pole? 10 foot “I wouldn’t touch that with a 10 foot pole” refers to the plague pole. Distance that a “miasma” can spread.

Settling the Disputes: Spontaneous generation: Redi, Pasteur
Causes of disease: Jenner, Semmelweiss, Lister, Pasteur, Koch
Redi’s Meat/Maggot experiments:
·         Developed first CONTROLLED experiment (fig 1. 10) (no maggots)
o   “covered jar” experiment (1670s)
·         Opened jar with meat (maggots on meat)
·         Meshed covered jar with meat (maggots on mesh)
·         Was able to replicate. Results refuted spontaneous generation for MACROorganisms
Dr. Edward Jenner           
·         Worried about people getting sick and dying. Several children
·         Small pox 1796: 2 out of 5 would die of small pox
·         Children who survived would be disfigured: leave craters
·         Cowpox gave people lots of immunity for small pox
·         Milk maids get cowpox, kind of like chicken pox, they did not get small pox
·         Interesting and (illegal) variolation in orient induced “mild” smallpox: put the pus from the legions and put in cut of another person. Cut slit and drag it into another.  They might have a STRONG life threating version but have a strong immune system.
·         Used pus from cowpox to create immunity from smallpox: first vaccination (1796)
o   Then he gave his children smallpox to see if they were immune. Vacca is Latin for cow.
·         They share proteins in the outer coat and your body recognized it as the same thing. Only disease that works: cowpox/smallpox it doesn’t work for any other disease
·         Picture of him doing it for his own child
Semmelweiss- asepsis (1847)
·         Hungarian doctor observed: had a bad attitude doctor? Maternity ward?
o   High “childbirth fever” deaths with doctors
o   Doctors- from cadavers to patients without disinfecting hands or instruments
o   Women would have babies in the alleys to get into midwife ward instead of doctors section
o   Introduced use of lime water for disinfection
o   Mortality rates decreased
o   He said materials but did not know about bacteria or viruses
o   When they didn’t adopt it fast enough, he became accusational: they were killing their patients if they didn’t adopt it: died of blood poisoning in mental institution. Not widely accepted because of how he presented it.
Lister – Aseptic Surgery (1850s)
·         Anesthesia increased mortality rates!
·         Expanded methods of Semmelweiss (less confrontational)
·         Introduced asepsis. (sepsis means spread: techniques not to spread bacteria, etc)
o   Heat sterilization of instruments
o   Disinfection of wounds and dressings
o   Disinfection of air during surgery (airborne particles can cause infection)
·         Did not mention germs but lived overlapping Pasteur
·         Father of Aseptic Surgery
·         Picture: circa 1870 surgery using the Lister techniques
·         Modern picture of surgery
Pasteur and Koch: the golden age of microbiology in 40 years will continue tomorrow.

Topic 1: Welcome to Microbiology!
...Where we boldly go into the realm of those smelly, dangerous, helpful, flavor-enhancing creatures called microorganisms.
What is expected of you in this course:
  • I provide:
    • Interesting, relevant material for your future careers
    • Lecture outlines
    • Tools for “getting” difficult material
      • review sheets
      • organizational charts
      • old tests
      • lab images
      • web resources
    • Tests on what was covered in class
    • Quick and fair grading
  • You agree to:
    • Attend each lecture
    • Skim assigned material before class, and re-read after covering topics in class
    • Be respectful of me and your peers by refraining from talking
    • Turn cell phones off or silent!
    • Take advantage of resources provided
    • Come on time for tests

Read “Microbiology Ground Rules” and initial top of page 4 if you accept the expectations of the course
  • Please put the following information on syllabus page 4
    • Your name (what you want me to call you also)
    • Home phone number for semester (area code, too, if different  from 336) and email address (if active)
    • Your major and/or career aspirations
    • All college science courses (include chemistry, physics, and biology; but NOT social sciences or nursing)
    • Anything else you think I need to know about you (medical, travel, kids, learning disabilities, etc.)

Microbiology is about:
(Fig. 4.3)
  • 30%: bacteria
    • How  prokaryotic cells work
    • clinically significant organisms (Staph, Strep, E.coli, anthrax, etc.)
    • antibiotic mechanisms
    • antibiotic resistance
  • 30% : viruses
    • How viruses work
    • Clinically significant viruses
        Influenza, Smallpox, Herpes (1-8), Hepatitis (A-E), AIDS
    • Antiviral drug mechanisms
  • 10%: Miscellaneous microbes
    • Prions
    • Protozoa
    • Fungi
  • 20%: Disease and immunity
    • Disease establishment
    • Epidemiology
    • Immune response
  • 10%: Food Microbiology
    • Food production
    • Food spoilage
    • Reducing risks


The History of Microbiology:
The Humble Beginnings:  Microscopy and Controversy

Microscopy
  • Robert Hooke: 


§  Anton van Leeuwenhoek (Fig. 1.2, 1.3)


Leeuwenhoek looked at:




Leeuwenhoek was first to describe:


Topic 2: The History of Microbiology:
The Humble Beginnings:
Microscopy and Controversy

Microscopy
Robert Hooke: (1665)
  • Contributions to microbiology:
  • "Micrographie"

 
 
Anton van Leeuwenhoek (1673-1723)   Fig. 1.1, 1.2
  • Royal Society of London

 
 
 
 
 
 
Leeuwenhoek looked at:
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Leeuwenhoek was first to describe:
 
 
 
 
 
 
 
 
 
 
 
 
Why did further discoveries languish for nearly 100 years?
 
 
 
 
 
 
Meanwhile, Two Controversies Sparked Debate and Experimentation
  • Spontaneous Generation
  • Theories of Disease

 
 
Spontaneous Generation:
 
 
 
 
 
 
 
 
 

 
 
Theories of Disease:




  • Miasma
     
     
     
     
Settling the Disputes:
Solving the spontaneous generation controversy:
  • Redi
  • Pasteur
Solving the disease controversy:
  • Jenner
  • Semmelweiss
  • Lister
  • Pasteur
  • Koch

 
 
 
Redi’s Meat/Maggot Experiments (1670s)
  • Famous "covered jar" experiment  Fig. 1.10

 
 
 
 
 
 
 
 
 
 
 
  What controversy did this settle?
 

 
  What method was developed?

 


Jenner’s Smallpox Experiments (1796)
2 observations:




“Variolation”
 
 
 
 
 Developed first:
 
 
 
 
Semmelweiss -Asepsis (1847)
 
 
 
 
 
 
 
 
Lister - Aseptic Surgery (1850’s)



6_27 class notes: Bacterial Anatomy cont.

Review from yesterday: diagram of bacterial cell (gram + and Gram -) differences

Optional parts found in some bacteria:

Plasmids are extra bits of information and not required for cell functions. 
Optional parts: Plasmids
 *Small "extra" segments of DNA
* Generic
* Self replicating
* Easily passed
* (flash drive compared to hard drive) 

r Plasmids = Resistance to antibiotics
* 3 Common Mechanisms of antibiotic resistance coded for on r plasmids: 
        - Efflux pump pumps out drug
        - Enzymes break down drug 
        - Enzymes change drug

f plasmids = fertility genes
     - initiate conjugation
     - make sex pili 


t plasmids = production of toxins

Common combined plasmid (picture example)

(one of the reasons diahrea is that it eases transmition of organism to others)

***draw plasmids in diagram***

**hairy stuff**

Sex Pili (Fig. 3.11)
Appearance:
hollow tube that contracts down upon itself pulls them together. only contruct when there was another bacteria that did NOT have the plasmid. s positive, s negative... surface molecule that indicates that they do or don't have it..

        Function: temporary (directions on F plasmid) 
                    - tubular pilin protein, contracts
                    - connect cells: allow DNA transfer
*Do not limit to just one partner: picture of 1 s positive giving plasmid to three s negative cells.

Fimbrae (Fig. 3.10) made of pillin protein


Appearance: short and numerous; proteinaceous

Function: for adhesion to surfaces
example: gonnorhia ... clean cervice (women).. urethra (men)

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004526/


Picture of the Gonorrhea Virus






Flagella (Fig. 3.6)
Appearance: hairlike structures
       - Stiff, curved 
       - rotate
                * counterclockwise = runs (positive simulus: food, good environment) 
                * clockwise = tumbles (negative such as toxin, bad environment)

Function: movement


Fig. 3.9
Run:  Flagellum moves in __counterclockwise_________ direction, bacterium moves ____quickly towards__________

Tumble:  Flagellum moves in ___clockwise_____ direction, bacterium moves _____away__________

Taxis: (chemo, photo, etc.): movement in response to stimulus
* more runs, fewer tumbles if detect positive stimulus ahead
* Fewer runs more tumbles if detect negative stimulus ahead.
 

Flagellar Arrangements: (Fig. 3.7)
Four common arrangments:
  • lophotrichous - tuft..... Lopho "tassle"

  • monotrichous -One flagellan all by itself........ mono = "one" 

  • peritrichous -surrounding......... peri = all over exterior

  • amphitrichous -both ends.........."amphi" = "both"

*** Gloey stuff**

Glycocalyx (Fig. 3.5)
    Mucoid layer:
       - polysaccharide or glycoprotein

    thick yellow, green, cloudy mucus = bacterial infection and not thin clear like your bodies natural response to a virus or allegries...
    • slime layer = loose layer
    • capsules = dens, thick layer
    • biofilms = shared layer, many cells

    Advantages of Glycocalyx/Capsules/Biofilms
    • Confer increased pathogenicity, or help with survival:
    1-neutralize drugs

    2- fool/ delay immune response (capsule first)

    3- adhere to surfaces

    4- avoid phagocytosis (White blood cells eating of cell) 


    Help cell survive:

     5- nutrient source during starvation

     6- storage of toxic wast products


    Endospores (Fig. 3.24) gram positive?

    * dormant, non-reproductive structures
    * formed inside cell in bad conditions        

     Sporulation process: cell creates an endospore

    * layers of petidoglycan + protein = spore coat
    * water removed
    * Dipicolinic acid added- heat stablity


    Spore coat composed of: petidoglycan

    spores contain decreased amounts of:
    spores contain high amounts of:

    Highly resistant to harsh environmental conditions:
    • heat (survive boiling)
    • harsh chemicals (alcohol, etc.) 
    • drying
    • lack of nutrients
    Germination in favorable conditions to normal vegetative cells.

    ·         Germination: spore to cell
    Endospore structure and types:
              * Bacterical spores are used to help identify the species by using three characteristics:
    1. location
    2. size 
    3. shape
    Anthrax picture: Endospore (central and oval), rectangle shaped
    *******oval large central endospore: green, pink.. force dye in spore? learn how to do it in lab*****


     ______________________________________________________________________________________________
     *Review of drug targets discussed earlier  Figure 10.2
    - attack ribosome
    - cell wall synthesis
    - DNA or RNA synthesis
    *ADDITIONAL DRUG TARGET-block enzyme

    __________________________________________________________________________________________________
    Unusual Bacteria:
    ·         Archaea  Fig. 3.26, 3.27
    • ancient
    • not "true" bacteria
      • Cell wall has NO peptidoglycan (protein) 
    • Simpler than bacteria (have hooks and not a lot of other things that bacteria has) 
    • methanogens
    • extremophiles
      • thermophiles (hot temperatures)
      • halophiles  (salty environments)
        • geothermal rift (archaea bacteria located) 

    ·         Mycoplasma Fig. 11.15
    • Some pneumonias (e.g. "walking" pneumonia)
    • no cell wall (can't survive if NOT in host tissue)

    ·         Rickettsia and Chlamydia Fig. 21.1, 21.6
      • Rocky Mountain Spotted Fever (Rickettsia) more come in NC then anywhere else in the world... rapid progressing disease...
      • Chalmydia: eye or venereal disease
      • replicate only inside host cell, burst out to infect new cells

    • Spirochaetes Fig. 3.8
      • Borrelia = lyme disease
      • treponema = syphilis
      • HUGE spiral cells
        • axial filament of internal flagella for motility ( drills through tissue because the WHOLE cell turns not just the flagella to move)


    Bacterial Growth

    Bacteria Reproduce by Cloning...
    • binary fission (Fig. 6.18, 11.2)= splitting in two.
      • genome is copied.
        • bidirectional 
        • topoisomerase fixes supercoils
      • Cell elongates
      • new cell wall and membrane separates the new cells.
    • generation time= time between divisions
     **************
     group activity? 

    * Ten bacterial cells were introduced into a test tube. In an hour, there are 80 cells present. What is the generation time of this particular species of bacteria? 
     10 >>> 20 >>> 40>>>80

    divides 3 times in 60 minutes... 60 min/3 = 20 minutes

    Generation time = every 20 minutes
    Bacterial Growth Curve (Fig. 6.19, 6.21)
    • Lag phase -

    • Exponential growth phase -

    • Maximum stationary phase -

    • Exponential death phase -

    • Minimum stationary phase OR crash