LSU BIOL 4106 Exam 1

microscopy

use of a microscope to view objects too small to be visible with the
naked eye

magnification

enlargement of the image of an object using a microscope

objective lens, ocular lens

Magnification is determined by multiplying the power of the ________ by the power of the _______.

resolution

degree to which detail in specimen is retained in a magnified image

contrast

difference in visual properties that makes an object distinguishable from other objects and the background

stains

Contrast is achieved using _________.

brightfield

Organisms/specimens are not living
Requires staining of specimens
Light is transmitted through specimen
Specimen appears dark on a light background

darkfield

• Utilizes an occult disk under the condenser lens
• Use for viewing live organisms in liquid samples
• Light is reflected by particles on the slide
• Specimens appear bright against a dark background

phase contrast

• Utilizes special condensers & lenses to align the image being seen
• Used under high magnifications to view details of living organisms

micrometer

scale within microscope eyepiece used to
measure size of a specimen

reticle

other name for micrometer

10x objective

Each unit equals 1.00 µm
No conversion needed

40x objective

Each unit equals 0.25 µm
Conversion: number of units counted multiplied by 0.25

100x objective

Each unit equals 0.10 µm
Conversion: number of units counted multiplied by 0.10

basophil

white blood cell that looks like chocolate chip cookie
Nucleus is often unsegmented/bilobed, cytoplasm contains large blue/purple granules

neutrophil

white blood cell that has horseshoe (immature) to sausagey (mature) shaped nucleus
pale/light pink cytoplasm
small granules in cytoplasm

erythrocyte (red blood cell)

pale pink with clear center

120

RBC's live approximately __ days.

thrombocytes (platelets)

stain dark purple
important factor in clotting

neutrophils

professional phagocyte
function: seek, destroy, die!

neutrophils

• Nonspecific ‐ engulf and digest foreign particles & bacteria
• First on scene
• Non‐dividing
• Granules contain enzymes

lymphocyte

A small ring of blue cytoplasm surrounding a dark blue/purple round/oval nucleus
look like water drops

helper T cells

‐ Help B‐cells
‐ Activate macrophages

natural killer cells (NK)

‐ Non‐specific
‐ Cytotoxic - kill infected cells

b-cells helper T, natural killer

types of lymphocytes (3)

B cells

responsible for antibody production

T cells

responsible for cell-mediated immunity

neutrophils

most common leukocyte

lymphocytes

2nd most common leukocyte

eosinophil

Allergic responses
Anti‐parasitic activity
Cytotoxic

eosinophilia

Increased number of eosinophils in the blood most commonly associated with allergies or parasitic infections

eosinophil

1 - 3 lobed nucleus, large reddish/pinkish granules in cytoplasm

basophil

Secrete histamines to promote inflammatory reaction

monocyte

Horseshoe/kidney shaped nucleus, cytoplasm is bluish and foamy in appearance and may contain vacuoles

monocyte

LARGEST white blood cell
Migrate into tissues to become macrophages

monocyte

Professional phagocyte
Destroy foreign substances & bacteria
Remove dead cells
Process antigenic information for lymphocytes

phylum Sarcodina

amebas - protoplasmic flow with and without discrete pseudopodia

class Lobosea

pseudopodia are lobose - finger shaped with a round tip

order Amoebida

typically -uninucleate, mitochondria, no flagellate stage, sexual

Entamoeba histolytica

causes amebic dysentery and amebiasis

amebas

-Single celled
-Motile; crawl around by rapidly extending and retracting pseudopodia
-Phagocytic
-Most are free-living in soil or water
-Only a few are parasitic and most of these are commensals
-Asexual reproduction

chromatoidal bars (chromatid bodies)

crystalline-like condensation of ribosomes
formed as trophozoite encysts

amebulae

metacystic trophozoites - small but basically morphologically the same as the large trophozoites

endosome/karyosome

like a nucleolus in nucleus (size and location are diagnostic feature in ameba)

chromatin granules

This is DNA; see on inner edge of nuclear membrane (size may help differentiate
between E histolytica and commensals)

food vacuoles

seen as round, light colored spots in trophozoites; are fluid-filled

commensals

non-pathogenic parasitic organisms

family Entamoebidae

parasites in digestive tract of man and other animals
most are commensals but some are serious parasites
species differentiated primarily on basis of nuclear structure

trophozoite, pre-cyst, cyst, metacyclic trophozoite

stages of Entamoebidae (4)

trophozoite

- nucleus, granules, food vacuoles in cytoplasm
-crawling and feeding

pre-cyst

- trophozoite has rounded up and begun to secrete a tough, hyaline cyst wall and begun to form chromatoidal bars

cyst

-nucleus divides to form 4 nuclei - "quadrinucleate"
- the mature infective stage

metacystic trophozoites (amebulae)

after excysting in the small intestine, cytoplasm and nuclei divide to
form 8 small trophozoites

worldwide

E. histolytica is found:

oral via fecal contamination

E. histolytica transmission

quadrinucleated cyst

E. histolytica infective stage

presence of red blood cells in food vacuoles within the trophozoites

E. histolytica diagnostic features

intestinal amebiasis/amebic colitis

Engulfment and lysis of epithelial cells creates ulcers in large intestine lining and results in colicky pain and protracted diarrhea lasting more than a few days

dysentery

bloody mucoid diarrhea
caused by ulcers eroding into the vascular part of intestinal mucosa

amebomas

palpable masses which are composed of ameba trophozoites, necrotic colon tissue and white blood cells
can be seen in chronic intestinal amebiasis

asymptomatic carriers

infected individuals who shed infective stages without showing any clinical signs of disease

extra-intestinal amebiasis

Invasive ameba erode ulcers deep into the intestinal wall through the submucosa and gain access to circulatory system, disseminating throughout the body

liver

most common extra-intestinal amebiasis site

lungs

second most common extra-intestinal amebiasis site

E. histolytica cyst

"cigar-shaped" chromatoidal bars (rounded ends)
-4 nuclei with central endosome/karysome (early cyst may have only 1or 2 nuclei)
-spherical on slides; nuclei stain dark; cyst wall won't stain

Entamoeba coli

the most common non-pathogenic species in the human colon
can co-exist with E. histolytica in colon
does not damage or feed upon host tissue (eats bacteria, protozoa, yeasts)

E. coli cyst

8 nuclei with eccentric endosome/karyosome
Chromatoidal body (bar) if present, is splintered appearance on ends

E. coli trophozoite

eccentric endosome/karyosome in nucleus
peripheral nuclear chromatin unevenly distributed
difficult to differentiate from E. histolytica trophs

E. gingivalis

Trophozoites only - NO cysts
Trophozoites identical to E. histolytica

E. gingivalis

commensal in mouth (currently some controversy about non-pathogenic status)
found in primates, dogs and cats
Transmission: direct - trophozoites via kiss, saliva, shared eating utensils

Iodamoeba buetschlii

infects man, other primates and pigs
most common ameba in pigs (probably
original host species) -low incidence in
humans

Iodamoeba buetschlii

commensal in large intestine (cecal area
primarily)
Feeds on bacteria in gut

I. buetschlii trophozoite

comparatively large nucleus
no chromatin granules at nuclear membrane
large endosome (about ½ diameter of nucleus)
food vacuoles

I. buetschlii cyst

single nucleus (always close to vacuole)
large endosome
large glycogen vacuole (occasionally may be two present)

Endolimax nana

Smallest of the amebas
commensal, lives in large intestine
endosome, large, irregular and variable in shape
nucleus without ring of chromatin at membrane

Naegleria fowlerii

Found worldwide in soil and warm, stagnant fresh water (including unchlorinated swimming pools)
opportunist

primary amebic meningoencephalitis (PAM)

-most cases are fatal within 5-10 days post infection
-Clinical symptoms include headache, fever, stiff neck, confusion, loss of coordination, coma and death.

Acanthomoeba spp

Distribution: worldwide
-found everywhere: soil; water including freshwater, sea water, brackish
water; airborne dust
-free-living - does not need host in life cycle but is an opportunist

cutaneous, inhalation

Acanthamoeba transmission (2)

skin, lungs, eyes

primary Acanthamoeba infection sites (3)

Acanthamoeba

Trophozoites small and may see spiky pseudopodia but probably not
- Cysts have a crystal like shape (not round)

ulcerative keratitis

Organisms and cysts get trapped by contact lens and chow down on your cornea

Granulomatous Amebic Encephalitis

This organism will invade the brain in immunocompromised individuals ONLY not immunocompetent individuals
-slower onset of fatality compared to PAM
-Ulcerative granulomas form in brain around parasites

phylum ciliophora

Possess cilia (compound or simple) in at least one stage of life cycle
Two kinds of nuclei:
- Macronucleus -very large
- Micronucleus
Reproduce by transverse binary fission
All have a direct life cycle

Balantidium coli

very large ciliate (largest protozoan parasite in humans)
only ciliate in humans (infection rate very low, only about 1%)
distribution world-wide; especially in tropical regions
many reservoir hosts -especially pigs

Balantidium coli cyst

no cilia
- dessication of feces - encystment occurs
- Encystment can occur outside the host.
- Trophozoites passed in feces can encyst outside of host
- fecal contamination of food or water
- living trophozoites and cysts are yellow or greenish in color

1) Unicellular, eukaryotic organisms
2) Motile, possessing one or several flagella
3) Many species parasitic in vertebrates, invertebrates and plants
4) Reproduce in the host by longitudinal binary fission
5) One infective stage many, many parasites in host!!

general characteristics of protozoan flagellates (5)

axoneme

microtubular rod that is central part of the flagellum; arises from kinetosome

axostyle

a stout microtubular rod that runs throughout the body. In trichomonads, it extends out from posterior end

kinetosome

origin of flagellum (found at base of flagellum) structure is identical to centrioles of other
eukaryotic cells

kinetoplast

a dark staining disc composed of circles of DNA -found within the mitochondrion

undulating membrane

formed by a flagellum bent back along and loosely attached to cell surface; involved in cell motility

Giardia and Diaentamoeba

flagellates with 2 transcriptionally active nuclei (2)

parabasal body

Golgi apparatus

hemoflagellates

live in the blood of host during one stage

heteroxenous

requires development within two hosts in life cycle

Trypanosoma equiperidum

only monoxenous hemoflagellate

pleomorphic

different morphological forms exhibited during life cycle
form exhibited depends upon host and location within that host

amastigote

round, no external flagellum, intracellular form within host cells

promastigote

kinetoplast is at the anterior end with the flagellum. No undulating membrane