Introduction to Microorganisms (6) PDF

Introduction to Microorganis ms Dr Anna Maceri School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation has been made available to you by and on behalf of Western Sydney Universit...

Introduction to Microorganis ms Dr Anna Maceri School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation has been made available to you by and on behalf of Western Sydney University for your personal use and study only. The material contained in this presentation is subject to copyright protection. You may not make any further copies and share the recorded lectures in whole or in part by any hardcopy, digital and or online technologies.  Objectives At the end of this session, students should be able to: Discuss why the study of microbiology is essential for health professionals and the importance of microorganisms in the environment. Describe how infectious diseases impact on our health Describe the major types of microorganisms and properties of bacterial cells Understand the unique characteristics of viruses and how viruses replicate  What is Microbiology? Study of organisms too small to be seen with the naked eye. Many are single-celled organisms. Major types: – Bacteria (eg E.coli) – Viruses(eg influenza) – Fungi (eg Candida) – Protozoa (eg Plasmodium) – Prions (eg mad cow disease) – Helminths (eg tape worms)  Why are microbes important? Micro-organisms are typically known for causing diseases that make people ill. However most microorganisms are beneficial!! Normal Microbiota on the Human Body. P.142  Why are microorganisms important? Beneficial association with plants, animals and humans. Example: normal flora. Industry: – Production of antibiotics – Production of chemical (eg. food additives) – Scientific research  Why is microbiology important to nurses? Understand infectious disease processes. Understand how the body combats disease. Practise infection control. Understand importance of correct collection of specimens. Understanding of laboratory results. Administration and monitor antibiotics. Major types of microorganisms Acellular Cellular Prokaryotes Eukaryotes Viruses Bacteria Fungi Prions Protozoa Algae Bacteria Procaryotic cell No nucleus - instead has a cluster of nuclear material called nucleoid Ribosomes present No other organelles Cell membrane present Cell wall present Capsule present that serves as protection from bacteria drying out. Flagella assist bacteria with mobility Pili or fimbriae assist with attachment of bacteria to surfaces. Please watch this video which describes bacteria: http://www.youtube.com/watch?v=fzIKJpcfXfo  Bacteria Cell Wall Gram positive Thick peptidoglycan layer Gram negative Thin peptidoglycan layer Additional cell membrane layer  How do Bacteria Reproduce? Binary Fission 1. Genetic material duplicates. 2. Chromosomes move to each end of cell. 3. Membrane and cell wall grow inward along middle to form a division. 4. Two identical cells are produced. Watch the following video for an explanation of binary fission: http://www.youtube.com/watch?v=3cD3U2pgb5w  Coccus (plural: cocci)- Shapes of spherical shape Staphylococci - clusters of round spheres Bacteria Streptococci - chain of round spheres Bacillus (plural: bacilli) - rod shaped Vibrio - curved, rod shaped Spirilla - spiral shaped  Viruses Not visible with light microscope. Not living. Genetic material encased in a capsid. Additional outer coating – envelope. Spikes present on envelope enable attachment to host cell.  How do Viruses Replicate? Attachment- of virus to host cell Penetration- of virus or nuclear material into the host cell Uncoating - removal of the capsid to release the nuclear material into the cytoplasm of the host cell Synthesis - nuclear material is replicated by the host cell Assembly - newly synthesised nuclear material and protein coating are assembled to form new viruses. Release - Viruses are released from host cell by rupturing the cell (resulting in death of host cell) or budding from cell membrane.  Fungi  Nucleus present  Cell organelles present  Cell structures similar to human cells  Fungi have a cell wall - animal cells do not have a cell wall  Different to plants as fungi do not contain chlorophyll (responsible for usually making plants green).  Protozoa  Nucleus present  Cell organelles present  Surrounded by a cell membrane - No cell wall  Some possess flagella, pseudopodia or cilia for movement  Some possess oral groove (ingestion of food particles) and anal pore  Some obtain nutrients by phagocytosis or absorption through cell membrane Prion  Prion is not a cellular micro- organism. Prion is misfolded (mutated) protein.  Mutated form causes prion disease.  Accumulates in brain causes degeneration of the nervous tissue and results in deterioration of muscle and dementia-like symptoms with eventual death within one year.  Caused 'Mad Cow' disease in UK in cattle. Spread to human can cause Creutzfeldt-Jakob disease (CJD).