Glossary
(Oo)cysts	An abbreviation for Cryptosporidium oocysts and Giardia cysts. See also: Cyst, Oocyst.
Amorphous	Lacking definite form; shapeless; no distinguishable internal structures; one classification of (oo)cysts observed with DIC.
Analyst	The analyst should have at least 2 years of college in microbiology or equivalent or closely related field. The analyst also should have a minimum of 6 months of continuous bench experience with Cryptosporidium and IFA microscopy. The analyst should have a minimum of 3 months experience using EPA Method 1622 and/or EPA Method 1623 and should have successfully analyzed a minimum of 50 samples using EPA Method 1622 and/or EPA Method 1623. See also Principal Analyst.
Analyst Verification	A routine process to verify analyst proficiency for consistent enumeration and organism characterization. At least monthly when microscopic examinations are performed, a slide containing 40-200 (oo)cysts is prepared. The total number of FITC positive (oo)cysts determined by each analyst using this slide must be within 10% of each other or performance verification must be repeated. Each analyst also determines DAPI and DIC categories for the same 10 (oo)cysts. Differences in the DAPI and DIC categorizations among analysts must be discussed, resolved, and documented.
Analyte	A protozoan parasite(s), Cryptosporidium and Giardia, tested for by Method 1622/1623.
Antibody	A highly specific protein, when in the presence of a particular antigen, will recognize and bind to that antigen. See also: Antigen, Monoclonal Antibody, and Bead-organism complexes.
Antigen	A protein unique to a cell which is recognized by a specific antibody to form an antigen-antibody complex. See also: Antibody, Bead-organism complexes.
Aspirate	To remove liquids by means of a suction device.
Axoneme	An internal flagellar structure that occurs in some protozoa, such as Giardia, Spironucleous, and Trichomonas.
Bead-organism Complexes	The complex formed when the antibody attached to the IMS bead binds with the antigen of the target organism forming an antigen-antibody bond. Also referred to as a bead pellet.
Column	Running vertically Source: Webster's English Dictionary
Contrast	The difference in visual properties that makes an object distinguishable from other objects and the background, determined by the difference in color and brightness of the object and other objects within the same field of view.
Cryptosporidium	A protozoan parasite potentially found in water and other media. Cryptosporidium is defined in Method 1622/1623 as an organism which exhibits brilliant apple green fluorescence under UV light, appropriate size (4 to 6 µm), and shape (round to oval), and excludes atypical organisms specifically identified as other microbial organisms by FITC and DIC (for example, those possessing spikes, stalks, appendages, pores, one or two large nuclei filling the cell, red fluorescing chloroplasts, crystals, spores, etc.).
Cyst	A phase or a form of an organism produced either in response to environmental conditions or as a normal part of the life cycle of the organism. It is characterized by a thick and environmentally resistant cell wall.
Cytoplasm	All cellular parts, particles, and semifluid substances enclosed by the plasma membrane except the nucleus.
DAPI	A nucleic acid stain (4',6-diamidino-2-phenylindole). As used in Method 1622/1623, it fluoresces blue when nuclei are stained.
DIC	Differential Interference Contrast microscopy; uses polarized light to enhance the observation of the structure of an organism.
Empty	One classification of (oo)cysts based on DIC observations in which no internal morphology or cytoplasm is observed.
Excyst	The process of a (oo)cyst rupturing and releasing the internal structures, specifically the escape of sporozoites from the oocyst.
Field of View	The area visible through the microscope lenses. Field of view decreases as magnification increases.
FITC	A fluorochrome (fluorescein isothiocyanate). In Method 1622/1623, it is used to label the monoclonal antibodies which target the cell wall antigen of both Cryptosporidium and Giardia.
Giardia	A protozoan parasite potentially found in water and other media. Giardia is defined in Method 1623 as an organism which exhibits brilliant apple green fluorescence under UV light, appropriate size (8 to 18 µm long by 5 to 15 µm wide), and shape (oval), and excludes atypical organisms specifically identified as other microbial organisms by FITC and DIC (for example, those possessing spikes, stalks, appendages, pores, one or two large nuclei filling the cell, red fluorescing chloroplasts, crystals, spores, etc.).
Immunomagnetic Separation (IMS)	A purification procedure that uses microscopic, magnetic particles coated with antibodies targeted to react with a specific pathogen in a fluid stream. Pathogens are selectively removed from other debris using a magnetic field.
IMS Control	10-mL of reagent water in a flat-sided tube, spiked with a known number of organisms, processed through IMS and staining, and used to determine recoveries of the IMS process.
Interpupillary Distance	Distance between the two eyepieces of a microscope. Typically it is adjustable to accommodate different users.
Köhler Illumination	The result of the technique used to properly align and adjust the incident light path to optimize the contrast and resolution of DIC microscopy. See Section 10.3.6 of Method 1623.
Long Term 2 Rule	EPA developed the Long Term 2 Enhanced Surface Water Treatment Rule (LT2 rule) to improve drinking water quality and provide additional protection from disease-causing microorganisms and contaminants that can form during drinking water treatment. The LT2 rule was published in the Federal Register on January 5, 2006. Source: Long Term 2 Enhanced Surface Water Treatment Rule
Median bodies	Prominent, paired organelles consisting of microtubules and found in the posterior half of Giardia. In G. intestinalis (from humans), these structures often have a claw-hammer or crescent shape, while in G. muris (from mice), the median bodies are round.
Method 1622/1623	The current EPA method for the determination of the identity and concentration of Cryptosporidium and Giardia in water by concentration, immunomagnetic separation (IMS), and immunofluorescence assay (FA) microscopy. Method 1622 is specific to the analysis of Cryptosporidium, Method 1623 covers the analysis of both Cryptosporidium and Giardia, these methods are designed to meet the survey and monitoring requirements of the U.S. Environmental Protection Agency (EPA). Source: Method 1622 Method 1623
Monoclonal Antibodies	A single type of antibody produced from the clone of a single cell that has been exposed to a specific antigen. See also: Antibody, Antigen.
Mucilage	A carbohydrate based, gelatinous substance surrounding some organisms.
Nucleus	A membrane-bound organelle containing genetic material. A prominent internal structure seen both in Giardia cysts and sometimes observed in Cryptosporidium oocysts. In Cryptosporidium oocysts, there is one nucleus per sporozoite. One to four nuclei can be seen in Giardia cysts.
Numerical Aperture	The measure of the ability of a microscope objective to gather light and resolve fine specimen detail at a fixed object distance.
Ocular Micrometer	A standard measurement tool added to one of the oculars of a binocular microscope. Also referred to as a reticle. Calibrate the ocular micrometer using a stage micrometer following the procedure in Method 1623. See also: Reticle, Stage Micrometer.
Oocyst	The encysted zygote of some sporozoa; e.g., Cryptosporidium. The oocyst is a phase or form of the organism produced as a normal part of the life cycle of the organism. It is characterized by a thick and environmentally resistant outer wall.
Parfocal	A microscope lens set-up and design in which an object will stay in focus or need minor adjustments to remain in focus when the magnification is changed.
Principal Analyst	The principal analyst (as defined for LT2ESWTR Laboratory QA Program) should have a BS/BA in microbiology or closely related field and a minimum of 1 year of continuous bench experience with Cryptosporidium and IFA microscopy. The principal analyst also should have a minimum of 6 months experience using EPA Method 1622 and/or EPA Method 1623 and should have analyzed a minimum of 100 samples using EPA Method 1622 and/or EPA Method 1623. See also Analyst.
Quantitatively Transfer	Transfer of a solution from one tube to another, using a measured amount, followed by two rinses.
Resolution	The ability of the optical components of a microscope to show details clearly, so the viewer sees two objects that are very close together as two objects rather than one.
Reticle	Measuring scale placed in the focal plane of the microscope ocular. Calibrate the reticle using a stage micrometer following the procedure in Method 1623. See also: Ocular Micrometer, Stage Micrometer.
Row	Running horizontally Source: Webster's English Dictionary
Sporozoite	A motile, infective stage of certain protozoans; e.g., Cryptosporidium. There are four sporozoites in each Cryptosporidium oocyst, and they are generally banana- or crescent-shaped.
Stage Micrometer	A calibrated scale for length measurement used in conjunction with a microscope. See also Ocular Micrometer, Reticle.
Total Magnification	Calculate by multiplying the magnification of the objective by the magnification of the ocular.
Vernier Coordinates	Spatial coordinates along an x- and y- axis. Recording of Vernier coordinates is necessary to locate a particular organism or artifact on a slide. See also: Vernier Scale.
Vernier Scale	A device invented by French mathematician Pierre Vernier, which consists of a fixed primary scale, and a smaller movable scale both marked in defined increments. By noting which lines on the Vernier scale lines up with any line on the primary scale, the tenth of a unit on the primary scale can be read with accuracy. See also: Vernier Coordinates.
Viability	The condition of being alive; specifically for Cryptosporidium and Giardia, the ability to excyst.