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Plant and Animal associationsSubstances which make up living material are:
Carbon Hydrogen Oxygen Sulfur Phosphorous Nitrogen
Potassium Iron Sodium Calcium Magnesium
With the primary being
CarbonHydrogenOxygenNitrogen
SulfurPhosphorous
**An organic compound always
contains carbon and hydrogen**
The most significant effects of microorganismson earth is their ability to recycle the primaryelements that make up all living things(especially C / O / N)
These elements occur in different forms
Different forms of carbon and nitrogen areneeded as nutrients by different types oforganisms
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The most important aspects of microbialmetabolism that are involved in the cycleof nutrients are: Primary production Decomposition or Biodegradation Nitrogen Fixation Oxygenic Photosynthesis
Primary Production
Photosynthesis Organisms which take up CO2 in the air and
convert it to organic material (CO2 fixation) This accounts for a large portion of available
organic carbon available for synthesis of cellmaterial
Examples of carbon fixers are planktonic algae andcyanobacteria which are responsible for approximately ! of the primary production on earth.
Planktonic algae are
Unicellular organisms which float in thewater and provide the source of carbon
from which aquatic life is derived
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Cyanobacteria
Aquatic and photosynthetic
Small, unicellular Grow into colonies large enough to see Oldest known fossils
Decomposition or biodegradation
Breakdown of complex organic material to formsof carbon that can be used by other organisms
No naturally occuring organic compound existsthat can not be broken down by microbes
Some synthetic compounds like teflon,styrofoam, plastics, pesticides and insecticidesare broken down slowly or not at all
Through the metabolic processes of respirationand fermentation organic molecules eventuallybreak down to CO2 which cycles back to theatmosphere.
Examples of this use: Waste treatment Compost Sewage treatment
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Nitrogen Fixation
Process used by some bacteria that removes N2from the atmosphere and converts it toammonia for use by plants and animals
Nitrogen fixation also results in soilreplenishment by agricultural processes
Some bacteria have symbiotic associations withplants
Other nitrogen fixers are free living in both soiland aquatic habitats
Oxygenic Photosynthesis
Occurs in plants, algae and cyanobacteria Results in the production of O2 in the
atmosphere 50% of the oxygen on earth is produced
by photosynthetic microorganisms (algaeand cyanobacteria
The cyanobacterium Synechococcus is aprimary component of marine andfreshwater plankton
This unicellular prokaryotic is involved in
primary production, nitrogen fixation andoxygenic photosynthesis, participating inthe cycles of carbon, nitrogen and oxygen
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Heterocyst Specialized nitrogen fixingcells formed by some filamentouscyanobacteria ie. Anabaena
Harmful Effects of Microbes
The primary harmful effects of microbeson our existence and civilization is thatthey are a cause of disease in animals andcrops and they are agents of spoilage anddecomposition of our foods
Microbes cause infectious disease Historically, infectious diseases are the most
significant cause of death in humans Until the beginning of the 20 th century it is
estimated that more than ! of the people
that ever lived died from either small pox(virus) or malaria (protozoa) Bacteria has also been the cause of some of
the most deadly diseases and epidemics inhistory including: tuberculosis, typhus, plague,diptheria, typhoid fever, cholera dysenteryand pneumonia
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Green Algae: Are single celled and colonial, often
possessing 2 flagellates per cell
Possess 2 types of chloroplasts andprovide photosynthesis for many otherspecies in symbiosis
Harmless but can cause water to turn anunpleasant green colour
Green Algae
Pediastrum boryanum colonies
Blue Green Algae
Can be dangerous as some speciesproduce toxins as they reproduce
Are unique in that they can reproduceunder anaerobic conditions Exist in cellular arrangements or colonies
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Blue Green Algae
1 under microscope 2- blue green algae in rafts
Diatoms
Are single celled algae that possess atough silica covering
Exist as unicellular individuals or ascolonies in ribbons and spirals
They exist at the bottoms of ponds andare not motile
Diatoms
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Dinoflagellates Microscopic, unicellular, flagellated often photosynthetic
protists commonly regarded as algae
Characterized by a transverse flagellum that encircles thebody and a longitude flagellum orientated perpendicular tothe transverse flagellum.
This gives a distinctive spiral to their swimming motion Both flagella are inserted at the same point in the cell wall This point is slightly depressed and is called the sulcus In heterotrophic (ones that eat other organisms), this is
where a conical feeding structure (peduncle) is projected toconsume food
Dinoflagellates con t Possess a unique nuclear structure at some stage in their
life cycle a dinokaryotic nucleus (as opposed toeukaryotic or prokaryotic), in which the chromosomesare permanently condensed and attached to the nuclearmembrane
Cell walls of many dinoflagellates is divided into plates ofcellulose (armour) within vesicles known as thecae
These plates form a distinctive topology known astabulation which is the main means for classification
There exists some that are heterotrophic and autotrophicand some that are both
Form a significant part of primary planktonic productionin both oceans and lakes
Dinoflagellates are usually haploid and reproduceprimarily by fission
In unfavorable conditions, such as lack of nutrientsand / or light, some species can alter their life cycledramatically. Two vegetative cells can join togetherand enter a stage that is similar to hibernation, withthe organism taking in fats and oils.
Its shape gets fatter and the shell gets hard.Sometimes spikes are formed
When conditions revert to favorable, thedinoflagellates break out of the cell, quickly reformtheir individual thecae and return to the dinoflagellatesat the beginning of the process
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Dinoflagellates
Fission Asexual reproduction (only one parentis involved)
Does not involve meiosis or fertilization Primary form of reproduction for single celled
organisms such as bacteria and protists All prokaryotes reproduce asexually Asexual reproduction has short term benefits
such as when rapid population growth isimportant or in a stable environment
Sexual reproduction offers the advantage ofgenetic diversity and adaption to change
and continued again
Besides being primary producers (important partof the food chain), dinoflagellates are known forproducing nasty toxins, particularly when theyoccur in large numbers called Red Tides
Besides being bad for a large range of marine life,red tides can also introduce non-fatal or fatalamounts of toxins into animals (shellfish)that maybe eaten by humans who are also effected by thetoxins
Many of these toxins are quite potent and haveneurological effects
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Red Tide
Common name for a phenomenon known as analgal bloom
Event in which estuarine, marine or freshwateralgae accumulate rapidly in the water column
These algae or phytoplankton are microscopic,single celled protists that can form dense visiblepatches near the waters surface
Certain species contain photosynthetic pigmentsthat vary in colour from green, brown to red
Red Tide continued Caused by a species of dinoflagellates present in
significant numbers (thousands or millions of cells permilliliter), to turn the water a hue of red
The term Red Tide , is often used in the USA to describea particular type of algal bloom common to the easterngulf of Mexico. This is caused by a species ofdinoflagellate known as Karenia brevis and these bloomsoccur almost annually in waters along Florida s coast.
Also common on the northern east coast of the US andparticularly in the Gulf of Maine. This type of bloom iscaused by another species of dinoflagellate known as
Alexandrium fundyense . These blooms severely disrupt
fisheries of these waters as the toxins in these organismscause shellfish to become poisonous for humanconsumption
In 1972 a red tide in New England was causedby another species called Alexandriumtamarense
It isn t clear what causes red tides or why theyoccur where they do. It can be entirely natural
or a result of human activities The frequency and severity of algal blooms in
some parts of the world have been linked toincreased nutrient loading from human activities
Coastal water pollution and systemic increase insea water temperature have also beenimplicated as contributing factors
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Quorum Sensing Is the ability of bacteria to communicate and
coordinate behaviour via bioluminescence or asignaling moleculeThe consequences of quorum sensing is thecoordination of certain behaviour between bacteriabased on the local density of bacteria
Can occur between a single species of bacteria ordifferent species
Can regulate a host of different processes,essentially serving as a simple communicationnetwork
Protists:
Diverse group of organisms made up ofeukaryotes that cannot be classified into anyother Kingdoms such as fungi, animals or plants
They do not have much in common beside arelatively simple organization .
Either they are unicellular or multi-cellularwithout highly specialized tissues
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One example being the amoebae:
Euglenid The euglenids are one of the best-known groups of
flagellates, commonly found in freshwater rich in organicmaterial
Many have chloroplasts and produce energy throughphotosynthesis
Distinguished mainly by the presence of a pellicle whichis comprised of protein strips underneath the cellmembrane
Move by flagella Primary mode of nutrition is phagocytosis, mostly
bacteria and smaller flagellates
Euglenia
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IllnessesCiguatera
TrypanosomesCryptosporidium
Ciguatera Foodborne illness poisoning in humans caused
by eating marine species whose flesh iscontaminated with a toxin called ciguatoxin
Present in many microorganisms (particularly themicro-algae Gambierdiscus toxicus), living intropical waters
Accumulates in lower level organisms , resultingin higher concentrations of the toxins at higherlevels of the food chain (biomagnification)
Ciguatoxin is very heat resistant so ciguatoxinladen fish (moray eel, barracuda, parrotfish)cannot be detoxified by cooking
Ciguatera con t Symptoms include gastrointestinal and
neurological effects. Nausea, vomiting, and diarrhea usually
followed by headaches and muscle aches,numbness and hallucinations
Can be sexually transmitted andtransmitted to breastfed infants via breastmilk
Symptoms can last from weeks to yearsand there is no effective treatment orantidote
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Trypanosomes
Group of protozoa distinguished by having only a singleflagellum
Exclusively parasitic and found primarily in insects A few species have life cycles involving a secondary host,
which may be a vertebrate or plant. These include several species that cause major diseases
in humans Most notable being: trypanosomiasis (African Sleeping
Sickness and South American Chagas Disease). Theseare caused by species of Trypanosoma
Trypanosomes
Cryptosporidium
Is a protozoan pathogen of the Phylum Apicomplexa causing a diarrheal illness called cryptosporidiosis.
Other Apicomplexan pathogens include the malariaparasite Plasmodium , and Toxoplasm
Unlike Plasmodium, which transmits via a mosquito,Cryptosporidium does not utilize an insect and completesits lifecycle in a single host, resulting in cyst stages,which are excreted in feces and are capable oftransmission to a new host
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Cryptosporidium con t
Typically an acute short term infection, but can becomesevere in children and those with a compromisedimmune system
Parasite is transmitted by environmentally hardy cystthat once ingested, resides in the small intestines
Has a spore phase (oocyst) that can survive for lengthyperiods outside a host and can resist many commondisinfectants (notably chlorine based)
Water purification methods include coagulation followedby filtration or boiling
New methods include ultraviolet light and ozonation
CryptosporidiumLifecycle
Fungus
Any member of a large group ofeukaryotic organisms that include yeastsand molds as well as mushrooms
Hyphae Main mode of vegetative growth Classified as a kingdom separate fromplants and animals
Helpful decomposition, nutrient cycling,direct source of food, fermentation
Harmful food spoilage, pathogens
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More definitions:
Autotroph organism that producescomplex organic compounds from simple
inorganic molecules using light Heterotroph Take in autotrophs as food.
These include animals, most fungi as wellas most bacteria and protozoa