Download 《微生物学》双语教学授课教案（含英文习题） Chapter1 The

《微生物学》双语教学授课教案（含英文习题）
Chapter1 The introduction of microbiology 第 1 章绪论
Microbiology（微生物学）：Microbiology is specialized area of biology
that deals with living things ordinarily too small to be seen with th
e naked eyes.
Microorganisms（微生物，microbe） ：Microorganisms are defined as the
organisms that are so small that ,normally,it cannot be seen without
the use of a mocriscope.
The word is therefore used to describe virus,bacreria,fungi,protozoom
and some algae.
Bacteria(细菌) ：Bacteria are some small,single celle organisms. Bec
ause they have no nucleus, the cells are described as prokaryotes.
Fungi(真菌)：Fungi (mushrooms（蘑菇）, molds（霉菌）, and yeasts) h
ave eukaryotic（真核的） cells (with a true nucleus). Most fungi are
multicellular.Fungi obtain nutrients by absorbing organic materi
al from their environment.
Protozoom(原生动物)：Protozoans are unicellular eucaryotes and are c
lassified according to their means of locomotion. Protozoans obtai
n nourishment by absorption or ingestion through specialized struc
tures.
Algae（藻类）：Alage are unicellular or multicellular eukaryotes t
hat obtain nourishment by photosynthesis.Algae produce oxygen and
carbohydrates that are used by other organisms.
Viruses（病毒）：Viruses are noncellular entities that are parasites o
f cells. Viruses consist of a nucleic acid core (DNA or RNA) surrounde
d by a protein coat. An envelope may surround the coat.
A brief history of microbiology
The science of microbiology did not start until the invention o
f the microscope in the mid 16th century and it was not until the
late 17th century that Antoine van Leeuwenhoek made their first reco
rds of fungi, bacteria and protozoa.
The late 19th century was the time when the first real breakthrou
ghs on the role of microbes in the environment and medicine were ma
de. Louis Pasteur disproved the theory of spontaneous generation
（自然发生）(that living organisms spontaneously arose from inorgan
ic material) and Robert Koch's development of pure culture technique
s allowed him to show unequivocally that a bacterium was responsible
for a particular disease. Since then the science has grown dramatic
ally as microbiology impinges on all aspects of life and the environ
ment.
Louis Pasteur stated that microorganisms are in the air everywhere
and offered proof of biogenesisLouis Pasteurˊdiscoveries led
to the developmemt of aseptic（无菌的）techniques used in labora
tory and medical procedures to prevent contamination by microor
angisms that are in the air.Louis Pasteur found that yeast ferm
ents（发酵） sugar to alchhol and that can oxidize alcohol to ac
etic acid.A heating process called pasteurization（巴斯德消毒）i
s used to kill bacteria in some alcohol beverages and milks.Jos
eph Lister introduced the use of a disinfectant（消毒） to clean
surgical dressings in order to control infections in humans.Ro
bert Koch proved that microorganisms transmit diseases.He used
a sequence of procedures called Koch’s postulates（科赫法则）,Wh
ich are used today to prove that a particular microorganism casues
a particular disease.Koch’s postulates：
Koch's postulates are a number of criteria that have been used in
the past to prove that a bacterium is responsible for a particular
disease.
1. The bacteria should be found in all cases and at all sites of t
he disease.
2. The bacteria should be isolated from the infected person and mai
ntained in pure culture.
3. The pure cultured microbe should cause symptoms of the disease o
n inoculation into a susceptible individual.
4. The bacteria should be reisolated from the intentionally infecte
d host.
The importance of microbiology：
microbes in our body
1. Everyone has microorganisms in and on the body Some microorganism
s live in humans and other animals and are needed to maintain the
animals health. these make up the normal flora（正常菌群）;
2.
Some Microorganisms cause disease.
3. The disease-producing properties of a species of microbe and the
host's resistance are important factors in determining whether a
person will contract a disease.
2.Microbes and Human Welfare
1. Microorganisms degrade dead plants and animals and recycle che
mical elements to be used by living plants and animals.
2. Bacteria are used to decompose organic matter in sewage. Biorem
ediation processes use bacteria to clean up toxic wastes.
3. Bacteria that cause diseases in insects are being used as biolo
gical controls of insect pests. Biological controls are specific f
or the pest and do not harm the environment.
4. Using recombinant DNA, bacteria can produce important human pr
oteins, such as insulin, beta-endorphin,and hepatitis B vaccine.
Microorganisms can be used to help produce foods.They are als
o food sources (single-cell protein) themselves.
3.As a basic biological science：microorganisms are the best model sy
stems for understanding basic life processes.
P
All cells have much in common, what is true for E. coli is also tru
e for elephant, only more so
P
Simple yet representative
P
Easiness and quickness to grow large quantity
Common characterizes of microorganism•Big surface/volume
•High absorption and transformation
•Rapid growth and reproduction
•Easiness to variation
••high adaptation to environment
•Diversity
Review question
1.Match the following people to their contribution toward the advanc
ement of microbiology.
__ Ehrlich
(a) First to observe bacteria
__ Fleming
(b) First to observe cells in
__ Hooke
plant material and name
_ Koch
__ Lister
them
(c) Disproved spontaneous
__ Pasteur
generation
_ Van Leeuwenhoek
(d) Proved that microorganisms can cause dise
ase
(e) Discovered penicillin
(f)
Used the first syntheticchemotheraputic ag
ent First to employ disinfectants in surgical
procedures
2.Match the following microorganisms to their descriptions.
__ Algae
(a) Not composed of cells
__ Bacteria
(b) Cell wall made of chitin
__ Fungi
(c) Cell wall made of
__ Protozoom
_ Viruses
peptidoglycan
(d) Cell wall made of cellulose; photosyntheti
c
(e) Complex cell structure lacking a cell wa
ll
3.Briefly state the role played by microorganisms in each of the fo
llowing.
(a) Biological control of pests
(b) Recycling of elements
(c) Normal flora
(d) Sewage treatment
(e) Human insulin production
4 The microbes were first formally observed in the mid-1600's, but th
e cell theory wasn't enunciated until 1839. Write a brief essay expla
ining why microbiology did not become a formally recognized science u
ntil Pasteur's time.
5. Compare and contrast the works of Louis Pasteur and Robert Koch, i
n terms of both applied and basic science.
6. Microorganisms can be both beneficial and harmful to humans. Altho
ugh we tend to emphasize the harmful microorganisms (infectious disea
se agents), many more are beneficial than harmful.
●In what ways are microorganisms important in the food , agriculture,
and industries?
7. Louis Pasteur´s work on spontaneous generation led to the developm
ent of methods for control of the growth of microorganisms. Robert Ko
ch developed criteria for the study of infectious microorganisms, and
developed the first methods for the growth of pure cultures of micro
organisms. Beijerinck and Winogradsky studied bacteria in soil and wa
ter, and developed the enrichment culture technique. In the twentieth
century, basic and applied microbiology have worked hand in hand to
yield a number of important practical advances and a revolution in mo
lecular biology.
●How did Pasteur´s famous experiment defeat the theory of spontaneous
generation?
●How can Koch´s postulates prove cause and effect in a disease?
●Who was the first person to use solid culture media in microbiology?
●What advantages do solid media offer for the culture of microorganis
ms?
●What is the enrichment culture technique and why was it a useful new
method in microbiology?
Chapter 2 prokayotic microorganism(原核微生物)第二章 原核微生物
prokaryotic cells
The chief distinguishing characteristics of procaryotic cells ar
e:
1.
genetic material (DNA) is not enclosed within a membrane.
2.
They lack other membrane bounded organelles.
Their DNA is not associated with histone proteins (special chro
mosomal proteins
found in eucaryotes).Their cell walls almo
st always contain the complex polysaccharide peptidoglycan
（肽聚糖）.Bacteria(细菌) and archaeobacteria（古细菌）
Bacteria are small, single-celled, microorganisms that belong to
a group called prokaryotes .
Bacteria are ubiquitous. They are a highly successful and diverse g
roup of organisms that can obtain energy and carbon from a wide range
of sources and therefore can colonize every niche on our planet from
deep ocean trenches to volcanic craters. In the 1970s, using DNA seq
uencing information, it was found that the group we know as the bac
teria could be split into two, the eubacteria
and the archaeobac
teria and it appears that these two groups evolved away from eac
h other very early in the history of living things at about the
same time that the first group of eukaryotic cells evolved. Membe
rs of the eubacteria include some of the more familiar bacteria s
uch as Escherichia colt （大肠埃希氏菌） and Staphylococcus aureus
（金黄色葡萄球菌） and are the prokaryotes that are best studied an
d understood. The archaebacteria are a very diverse group of orga
nisms, which differ from the eubacteria（真细菌 0 in a number of f
eatures having, in particular, very different cell walls and membr
anes. This group includes bacteria that are capable of existing i
n extreme environments。
Size, Shape, and Arrangement of Bacterial Cells
1
Most bacteria are from 0.20 to 2.0 /µm in diameter and from 2 t
o 8µm in length.
2
The three basic bacterial shapes are coccus(spheres), bacillus
(rods),and spiral (twisted).
3
In addition to the three basic shapes, there are star-shaped ce
lls (genus Stella) and recently discovered square, flat cells (h
alophilic(嗜盐的) archaeobacteria) and triangular cells (Haloarcu
la)
4
the shape of a bacterium is determined by heredity.However, a n
umber of environmental conditions can alter that shape.Pleomor
phic(多型性的) bacteria can assume several shapes.
Gram Stain：
The eubacteria are frequently divided into two groups on the basis of
their reaction to a stain devised by Christian Cram in 1884. The d
ifferential reaction to the staining procedure is because of the st
ructure of the cell wall in these two groups of bacteria. Gram-posit
ive bacteria have a single membrane called the cytoplasmic (or plasma)
membrane, surrounded by a thick layer of peptidoglycan (20-80 nm). T
he Gram-negative bacteria have only a thin layer of peptidoglycan (1
-3 nm) but on the outside of this there is a further outer membrane
which acts as an additional barrier.
The procedure for the Gram stain is as follows. Fixed cells are st
ained with a dark stain such as crystal violet, followed by iod
ine which complexes with the stain in the cell wall of the bacteri
a. Alcohol is added, which washes the dark stain of crystal violetiodine out of ceils that have thin cell walls but not from those th
at have thick cell walls. Finally, a paler stain such as carbol fusc
hin, called a counter stain, is added which stains the decolorized c
ells pink but is not seen on the dark staining cells that retained
the first stain. The cells that retain the stain (with thick cell wa
lls) are called Gram-positive and appear dark purple under light mi
croscopy. The ones that lose the stain (with thin cell walls and
an outer membrane) are called Gram-negative and stain pink or pale p
urple
The Cell Wall
1.
The cell wall surrounds the plasma membrane and protects the ce
ll from changes in osmotic pressure（渗透压）and provides rigidi
ty and strength.
2.
The bacterial cell wall consists of peptidoglycan（肽聚糖）, a p
olymer consisting of NAG and NAM and short chains of amino aci
ds.
3.
Gram-positive（革兰氏阳性） cell walls consist of many layers of
peptidoglycan and also contain teichoic acids（垣酸）.
4.
Gram-negative（革兰氏阴性）bacteria have a lipidprotein-lipopoly
saccharide-phospholipid outer membrane surrounding a thin pept
idoglycan layer.
5.
The outer membrane protects the cell from phagocytosis and penic
illin（青霉素）, lysozyme（溶菌酶）, and other chemicals.
6. Porins（孔蛋白）are proteins that permit small molecules to pass
through the outer membrane; specific channel proteins allow ot
her molecules to move through the outer membrane.
7. The lipopolysaccharide（脂多糖，LPS） component of the outer me
mbrane consists of sugars that function as antigens and lipid
A, which is an endotoxin（内毒素）.
teichoic acid:
Gram-positive cell walls also contain large amounts of another polym
er, called teichoic acid, made up of glycerol or ribitol joined b
y phosphate groups. D-Ala, glucose or sugars may be attached to the
glycerol or ribitol and the polymers are attached either directly t
o the NAM in the peptidoglycan or to lipids in the membrane (in th
is case they are called lipoteichoic acids). The function of these
molecules is unclear but they may have a role in maintaining the str
ucture of the cell wall and in the control of autolysis.
periplasmic space（周质空间）
The outer membrane of Gram-negative bacteria acts as an additiona
l barrier protecting the peptidoglycan from toxic compounds such
as lysozyme which act on the cell wall. It creates an aqueous s
pace between the two membranes called the periplasmic space whic
h is thought to have a gel-like structure with a loose network o
f peptidoglycan running through it. Estimates as to the width of
the peptidoglycan vary from 1-71 nm but it has proved to be di
fficult to obtain a real definitive value. The periplasmic space
contains a range of proteins associated with:
• transport of nutrients into the cell;
• enzymes that are involved in nutrient acquisition such as pro
teases;
• enzymes that defend the cell against toxic chemicals such as
в-lactamases that destroy penicillin.
outer membrane
The outer membrane of Gram-negative bacteria is made up of pho
spholipids membrane,but it also contains some unique features
1.
Pores formed by proteins called porins such as OmpF and OmpC
that allow the passive diffusion of small molecules into th
e periplasmic space.
2.
An abundant small lipoprotein called Braun's lipoprotein th
at is covalentlybound to the peptidoglycan and is embedded
in the outer membrane by it shydrophobic lipid, therefore ho
lding the peptidoglycan and outer membraneclose together.
3.
LPS molecules are found in the outer leaflet of the outer mem
brane projecting into the surrounding medium.
Atypical（缺陷的） cell walls
1.
Mycoplasma（支原体） is a bacterial genus that naturally lacks c
ell walls.
2. Archaeobacteria have pseudomurein（假肽聚糖）; they lack peptid
oglycan.
3. .L forms are mutant bacteria with defective cell walls.
Archaeobacterial cell walls
One of the distinctive features of archaebacteria is the nature o
f the lipids in the plasma membrane which, unlike the ester-linked l
ipids of eubacteria and eukaryotes are ether-linked to glycerol. T
hey are also long chained and branched. Archaebacterial cell walls
and envelopes show great diversity and complexity in structure. They
do not contain peptidoglycan although some do have a similar compou
nd called pseudomurein which contains N-acetyl-alosaminuronic acid in
place of muramic acid. Another common type of cell wall is the S-la
yer, a two-dimensional, paracrystalline, array of protein or glycop
rotein on the cell surface. Others have thick polysaccharide walls
outside their plasma membrane.
DAMAGE TO THE CELL WALL
peptidoglycan used to be a target for antimicrobial agents that des
troy prokaryotic cells specifically, but do not harm eukaryotic ce
lls; an example of this is the antibiotic penicillin (Topic F7). Lys
ozyme, a natural antibacterial agent found in tears and natural secre
tions, breaks down the linkage between NAM and NAG. Removal of the ce
ll wall under conditions where the osmolarity of the medium is the s
ame as the inside of the cell (isotonic solution) results in the for
mation of round protoplasts(原生质体) (Gram-positives) or spheropla
sts(球形体) (Gram-negatives) which survive as long as the isotonici
ty is maintained. These structures lyse, however, if placed in a dil
ute medium, illustrating the importance of peptidoglycan to the ce
lls' survival.
1.
In the presence of lysozyme, gram-positive cell walls are destr
oyed and the remaining cellular contents are referred to as a
protoplast.
2.
In the presence of lysozyme, gram-negative cell walls are not
completely destroyed and the remaining cellular contents are r
eferred to as a spheroplast.
3.
Protoplasts and spheroplasts are subject to osmotic lysis.
4.
Antibiotics such as penicillin interfere with cell wall synthesi
s.
PLASMA (CYTOPLASMIC) MEMBRANE
1
The plasma membrane encloses the cytoplasm and is a phospho
lipid bilayer with protein (fluid mosaic).
2
most of bacteria lack of steriol（固醇）
3
The plasma membrane is selectively permeable.
4
Plasma membranes carry enzymes for metabolic reactions, su
ch as nutrient breakdown, energy production, and photosynth
esis.
5
Mesosomes—irregular infoldings of the plasma membrane—a
re now considered artifacts
6
.Plasma membranes can be destroyed by alcohols and polymyx
in.
CYTOPLASM
1
Cytoplasm is the fluid component inside the plasma membr
ane.
2
The cytoplasm is mostly water, with inorganic and organic
molecules, DNA, ribosomes, and inclusions.
RIBOSOMES
1
The cytoplasm of a procaryote contains numerous 70S ribosomes;
ribosomes consist of rRNA and protein.
2
Protein synthesis occurs at ribosomes; this can be inhibited b
y certain antibiotics.
INCLUSIONS
1
Inclusions（内含物） are reserve deposits found in procaryotic
and eucaryotic cells.
2
Among the inclusions found in bacteria are metachromatic gran
ules（异染粒） (inorganic phosphate), polysaccharide granules (，
多糖，usually glycogen or starch), lipid inclusions（脂滴）,sulf
ur granules（硫粒）, carboxysomes (，羧酶体，ribulose 1,5-diphosph
ate carboxylase), and gas vacuoles（气泡）.
NUCLEAR AREA
1. The nuclear area contains the DNA of the bacterial chromosome. B
acteria can also contain plasmids, which are extrachromosomal DN
A circles.
capsule or slime layer
1.
capsule（荚膜） or slime（黏液层） layer is a gelatinous polysa
ccharide and/or polypeptide covering.
2.
3.
Capsules may protect pathogens from phagocytosis（吞噬）.
Capsules provide adherence to surfaces, prevent desiccation,
and may provide nutrients.
FLAGELLA
1.
Flagella（鞭毛） are relatively long filamentous appendages cons
isting of a filament, hook, and basal body.
2.
Procaryotic flagella rotate to push the cell.Motile（运动）.
3.
bacteria exhibit taxis（趋性）—positive taxis is movement towar
d an attractant and negative taxis is movementaway from a rep
ellent.
FIMBRIAE AND PILIF
1.
fimbriae（菌毛） and pili（性毛） are short, thin appendages.
2.
Fimbriae help cells adhere to surfaces.
3.
Pili join cells for the transfer of DNA from one cell to anoth
er.
ENDOSPORES（芽孢）
1.
Endospores are resting structures formed by some bacteria for
survival during adverse environmental conditions.
2.
The process of endospore formation is called sporulation; the
return of an endospore to its vegetative state iscalled germinat
ion.
Endospores are a method as survival, not one of reproduction. Certain
bacteria will form a spore within their cell membrane (an endospore)
that allows them to wait out deteriorating environmental conditions.
Certain disease causing bacteria (such as the one that causes the di
sease Anthrax) can be virulent (capable of causing an infection) 1300
years after forming their endospore!）
BACTERIAL DIVISION
1.
The normal reproductive method of bacteria is binary fiss
ion, in which a single cell divides into two identical cell
s.
2.
Some bacteria reproduce by budding., aerial spore formation,
or fragmentation.
binary fission（二分裂）
The method by which bacteria reproduce. The circular DNA molecule is replic
ated; then the cell splits into two identical cells, each containing an exact c
opy of the original cell's DNA.
Actinomyces
Actinomycetes(放线菌) are filamentous, gram-positive bacilli that
form a branching mycelium.
Cyanobacteria（蓝细菌）：
Blue-green bacteria;unicellular or filamentous chains of cells that carry
out photosynthesis.
Rickttsias , chlamydias and mycoplasmas
The rickttsias（立克次氏体） and chlamydias（衣原体） are gram-negative o
bligate intracellular parasites that key metabolic enzymes.
The rickettsias are extremely small, pleomorphic rods or coccobac
illi that cannot synthessiz their own ATP. Most have a complex life-s
tyle that cyces between arthropod vectors and vertebrate hosts.
The rickettsias are ususlly transmitted by tickor tick feces.
The chlamydias are small, gram-negative, pleomorphic, intracellular
parasites that have no catabolic pathways. They exist in two forms: t
he elementary body, which is the form transmitted between human hosts
through direct contact and body secretions, and the reticulate body,
which multiplies intracellularly.
Chlamydia trachomatis（沙眼衣原体） is the agent of several STDs: NG
U (nongonococcal urethritis),pelvic inflammatory disease, and lymphog
ranuloma venereum. It also causes ocular trachoma, a serious eye infe
ction.
Chlamydia pneumoniae(肺炎衣原体) is the agent of respiratory infecti
ons in young adults and asthmatics.
Chlamydia psittaci（鹦鹉热衣原体） is the agent of ornithosis, an infl
uenza-like disease carried by birds that has serious systemic complicat
ions if untreated. Antibiotic therapy is usually successful.
Mycoplasmas（支原体） are tiny pleomorphic bacteria that lack a cell
wall. Although most species are parasitic, mycoplasmas can be culture
d on complex artificial media. They are considered membrane parasites
because they bind tightly to epithelial linings of the respiratory a
nd urogenital tracts.
Mycoplasma pneumoniae(肺炎支原体) is the agent of primary atypical p
neumonia (walking pneumonia).
M. hominis(人型支原体) and M. urealyticum(脲支原体) are agents of se
xually transmitted infections of the reproductive tract and kidneys,
and more recently, of fetal infections.
M. incognitos is a recently identified pathogen that causes systemic
infection by suppressing the immune system.
Chapter 2
Review question
1.Diagram each of the following flagellar arrangements:
(a) Lophotrichous
(b) Monotrichous
(c) Peritrichous
2.Endospore formation is called It is initiated
by __ . Formation of a new cell from an endospore is called
. .
This process is triggered by
3.Draw the bacterial shapes listed in a, b, and c. Show how d, e,
and f are special conditions of a, b, and c, respectively.
(a) Spiral
(d) Spirochete
(b) Bacillus
(e) Streptobacilli
(c) Coccus
(f) Staphylococci
4. List three differences between procaryotic and eucaryotic cells.
5.Match the structures to their functions.
A:Protection from osmotic lysis
Cell wall
B: Attachment
Endospore
C: Protection from phagocytes
Fimbriae
Flagella
D: Resting
6.E:
OfProtein
whatsynthesis
value is each of the following to the
cell?
F: Selectively permeable
caupsle
(a)
Metachromatic
granules
I: Transfer
of genetic material
Plasma membrane
Ribosome
(b) Polysaccharide granules
(c) Lipid inclusions
(d) Sulfur granules
(e) Carboxysomes
(f) Gas vacuoles
7. Why is an endospore called a resting structure? Of what advantage
is an endospore to a bacterial cell?
8. Compare and contrast the following:
Protoplasts and spheroplasts
penicillin and l
yzosome
Flagella and fimbriae
amydias
rickttsiae and chl
9.Answer the following questions using the diagramsbelow, which
represent cross sections of bacterial cell walls.
(a) Which diagram represents a gram-positive bacterium? How ca
n you tell?
(b) Explain how the Gram stain works to distinguish between th
ese two types of cell walls.
(c) Why does penicillin have no effect on most gram negative ce
lls?
(d) How do essential molecules enter cells through each wall?
Teichoic acid
Lipopolysac
charide
Peptidoglycan
Phospholipi
d
Lipoprotein
Cell membrane
Peptidoglyc
an Cell mem
10.Why can procaryotic cells be smaller than eucar
yotic cells and still carry on all the functions fo
r life?
brane
11.Two types of procaryotic cells have been distinguished: eubacteri
al and archaeobacterial. How do these cells differ from each other?
How are they similar?
12.
What is the evolutionary advantage of the monolayer often found
in Archaeal membranes?
13. Bacillus subtilis is a common soil bacterium. What genus does B.
subtilis belong to?
14. Although prokaryotes and eukaryotes are distinguished by nuclear
structure, other important differences exist between these two cell t
ypes. Prokaryotes are smaller in size than eukaryotes, and eukaryotes
contain a membrane-enclosed nucleus and organelles within which many
important functions are carried out. The small size of prokaryotic c
ells affects their physiology, growth rate, and ecology.
●List three morphological types of prokaryotes.
●What is a flagellum, and what does it do?
●What physical property of cells increases as cells become smaller?
15. The cell walls of Bacteria contain a polysaccharide called peptid
oglycan. This material consists of strands of alternating repeats of
N-acetylglucosamine and N-acetylmuramic acid, with the latter cross-l
inked between strands by short peptides. Archaea lack peptidoglycan b
ut contain walls made of other polysaccharides or of protein. The enz
yme lysozyme destroys peptidoglycan, leading to cell lysis.
●List the monomeric components of peptidoglycan.
●Why is peptidoglycan such a strong macromolecule?
●How does psuedopeptidoglycan resemble peptidoglycan? How do the two
molecules differ?
●How is a protoplast generated?
16.In addition to peptidoglycan, Gram-negative Bacteria contain an o
uter membrane consisting of lipopolysacchaaride, a protein, and lipo
protein. Proteins called porins allow for permeability across the ou
ter membrane, and a space called the periplasm is present, which con
tains various proteins involved in important cellular functions.
●What components constitute the LPS layer of Gram-negative Bacteria?
●What is the function of porins, and where are they located in a Gram
-negative cell wall?
●Why does alcohol readily decolorize Gram-negative bacteria?
17. The endospore is a highly resistant differentiated bacterial cell
produced by certain types of Gram-positive Bacteria. Spore formation
leads to a nearly dehydrated spore core that contains essential macr
omolecules and a variety of substances, such as calcium dipicolinate
and small acid-soluble proteins, absent from vegetative cells. Spores
can remain dormant indefinitely but germinate quickly when the appro
priate trigger is applied.
●What is dipicolinic acid, and where is it found?
●What are SASPs, and what are their functions?
●What happens when an endospore germinates?
chapter 3 eukaryotic microorganisms
第 3 章 真核微生物
Eukaryote cell
A type of cell found in many organisms including single-celled protoz
oom and multicellular fungi, plants, and animals; characterized by a
membrane-bounded nucleus and other membraneous organelles
eukaryotic cells construct
Appendages (cilia, flagella), glycocalyx, cell wall, cytoplasmic (or
cell) membrane, ribosomes, organelles(nucleus, nucleolus, endoplasm
ic reticulum, Golgi apparatus, mitochondria, chloroplasts, cytoskeleto
n, microfilaments.
Main characterstic of eukarytic cells
1. The nucleus, which contains DNA in the form of chromosomes, is t
he most characteristic eukaryotic organelle.
2. The nuclear membrane is connected to a system of parallel membran
es in the cytoplasm, called the endoplasmic reticulum.
3. The endoplasmic reticulum provides a surface for chemical reacti
ons, serves as a transporting network, and stores synthesized
molecules.
4. 805 ribosomes are found in the cytoplasm or attached to the endo
plasmic reticulum.
5. The Golgi complex consists of cisternae. It functions in secreti
on, carbohydrate synthesis, and glycoprotein for mation.
6. Mitochondria are the primary sites of ATP production.They conta
in small 70S ribosomes and DNA, and they multiply by fission.
7. Chloroplasts contain chlorophyll and enzymes for photosynthesis.
Like mitochondria, they contain 70S ribosomes and DNA and mult
iply by fission.
8. Lysosomes are formed from Golgi complexes. They store powerfu
l digestive enzymes.
9. A pair of cylindrical structures called centrioles that are invo
lved in cell division are near the nucleus.
10.Both flagella and cilia contain a "nine pairs + two pairs"arrang
ement of microtubules.
Major Groups of eukaryotic microorganisms
eucaryotic microorganisms include the Fungi ,algae and protozoom..
Fungi
Fungi is composed of non-photosynthetic species Fungi include yeasts
(unicellular budding cells) and molds (filamentous cells called hypha
e,菌丝) and some macroscopic fungi(mushrooms).
Major Groups of fungi: The four important divisions among the terrestr
ial fungi, given with sexual spore type, are Zygomycota（接合菌纲）
(zygospores，接合孢子), Ascomycota（子囊菌纲） (ascospores，子囊孢子),
Basidiomycota（担子菌纲） (basidiospores，担孢子), and Deuteromycot
a（半知菌纲） (no sexual spores).
Yeast
1.
Yeasts are single cells that form buds（芽体） and sometimes short
chains called pseudohyphae（假菌丝）.
2.
Yeasts are 5~20μm in length and 1~5μm in diamater.
3.
The majority are harmless saprobes living off organic substrates
such as glucose. A few are parasites, living on the tissues of oth
er organisms, but none are obligate.
4. Yeast cell walls consist of glucan and mannan.
5.
plasma membranes contain carbohydrate sattached to the protei
ns and sterols not found in prokaryotic cells.
most of yeast cell have large vacuolars(液泡).budding is the main rep
roduction style of yeast.In sexual reproduction, spores are formed
through fusion of male and female strains and the formation of a
sexual called ascospore.Molds
hyphae are characteristic of the filamentous fungi called molds. some
fungi (mushrooms) produce multicellular structures such as fleshy fr
uiting bodies.
Importance of molds
Essential decomposers of plant and animal detritis in the environmen
t with return of valuable nutrients to the ecosystem. Economically ben
eficial as sources of antibiotics; used in making foods and in genetic
studies. Harmful plant pathogens; decompose fruits and vegetables; se
veral fungi cause infections, or mycoses; some produce substances that
are toxic if eaten.
Hyphae of molds
Hyphae can also be classified according to their particular functio
n. Vegetative hyphae(营养菌丝) (mycelia) are responsible for the visi
ble mass of growth that appears on the surface of a substrate and pen
etrates it to digest and absorb nutrients. During the development of
a fungal colony, the vegetative hyphae give rise to structures calle
d reproductive, or aerial hyphae（繁殖菌丝）., which orient verticall
y from the vegetative mycelium. These hyphae are responsible for the
production of fungal reproductive bodies called spores.
Cell wall of molds
The main material of fungal cell walls is chitin.
Reproduction of molds
Primarily through spores formed on special reproductive hyphae .Their p
rimary means of reproduction involves asexual and sexual spores.
Asexual Spore
1. Sporangiospores（孢囊孢子） are formed by successive cleavages within
a saclike head called a sporangium,which is attached to a stalk, the
sporangiophore. These spores are initially enclosed but are released w
hen the sporangium ruptures.
2. Conidia（分生孢子）(conidiospores) are free spores not enclosed by a
spore-bearing sac. They develop either by the pinching off of the tip
of a special fertile hypha or by the segmentation of a preexisting v
egetative hypha. Conidia are the most common asexual spores
3. arthmspore (节孢子) A rectangular spore formed when a septate hypha
fragments at the cross walls.
4. chlamydospore（厚垣孢子） (klams-ih'-doh-spor) A spherical conidium
formed by the thickening of a hyphal cell. It is released when the su
rrounding hypha fractures, and it serves as a survival or resting cel
l.
sexual spores
The majority of fungi produce sexual spores at some point. The natu
re of this process varies from the simple fusion of fertile hyphae of
two different strains to a complex union of differentiated male and fe
male structures and the development of special fruiting structures. Fo
ur different types of sexual spores have been identified, but we will
consider the three most common: zygospores（接合孢子）, ascospores（子
囊孢子）,oospore）卵孢子）， and basidiospores（担孢子）.
Zygospores* are sturdy diploid spores formed when hyphae of two opp
osite strains (called the plus and minus strains) fuse and create a dip
loid zygote that swells and becomes covered by strong, spiny walls. Whe
n its wall is disrupted, and moisture and nutrient conditions are suita
ble, the zygospore germinates and forms a sporangium. Meiosis of diplo
id cells of the sporangium results in haploid nuclei that develop into
sporangiospores. Both the sporangia and the sporangiospores that aris
e from sexual processes arc outwardly identical to the asexual type, bu
t because the spores arose dom the union of Iwo separate fungal parent
s, they are not genetically identical.
In general, haploid spores called ascospores are created inside a spe
cial fungal sac. or ascus.Although details can vary among types of fung
i, the ascus and ascospores are formed when two different strains or s
exes join together to produce offspring. In many species, the male sexu
al organ fuses with the female sexual organ. The end result is a number o
f terminal cells, each containing a diploid nucleus. Through differentia
tion, each of these cells enlarges to form an ascus, and its diploid nu
cleus undergoes meiosis (often followed by mitosis) to form four to eig
ht haploid nuclei that will mature into ascospores. A rise ascus breaks
open and releases the ascospores. Some species form an elaborate fruit
ing body to hold the asci.
Basidiospores: are haploid sexual spores formed on the outside of a
club-shaped cell called a basidium)
Chapter 4 VIRUSES
第四章 病毒
A virus is a submicroscopic infectious particle composed of a protein coat
and a nucleic acid core. Viruses, like cells, carry genetic information encoded
in their nucleic acid, and can undergo mutations and reproduce; however, they
cannot carry out metabolism, and thus are not considered alive. Viruses are cla
ssified by the type of nucleic acid they contain, and the shape of their protei
n capsule.
General Characteristics of Viruses
1. Depending on one's viewpoint, viruses may be regarded as
tionally
complex
excep
aggregations of nonliving chemicals or as ex
ceptionally simple living microbes.
2. Viruses contain a single type of nucleic acid (DNA or RNA) and
a protein coat, sometimes enclosed by an envelope composed of l
ipids, proteins, and carbohydrates.
3. Viruses are obligatory intracellular parasites. They multiply b
y using the host cell's synthesizing machinery tocause the synt
hesis of specialized elements that can transfer the viral nuc
leic acid to other cells.
4. A virion is a complete, fully developed viral particle compos
ed of nucleic acid surrounded by a coat.
HOST RANGE
1. Host range refers to the spectrum of host cells in which a virus
can multiply.
2. Depending on its host range, a virus is generally classified a
s an animal virus, bacterial virus (bacteriophage), or plant vi
rus. A virus can infect only certain species within each clas
s.
3. Host range is determined by the specific attachment site on the
host cell's surface and the availability of host cellular factor
s.
SIZE
1. Viral size is determined by filtration through membrane filters,
ultracentrifugation, and electron microscopy.
2. Viruses range from 20 to 300nm in diameter.
Viral Structure
NUCLEIC ACID
1. The proportion of nucleic acid in relation to protein in viru
ses ranges from about 1% to about 50%.
2. Viruses contain either DNA or RNA, never both, and the nuclei
c acid may be single- or double-stranded, linear or circular, o
r divided into several separate molecules.
CAPSID AND ENVELOPE
1. The protein coat surrounding the nucleic acid of a virus is ca
lled the capsid（衣壳）.
2. The capsid is composed of subunits, the capsomeres（衣壳粒）,
which can be a single type of protein or several types.
3. The capsid of some viruses is enclosed by an envelope consisti
ng of lipids, proteins, and carbohydrates.
4. Some envelopes are covered with carbohydrate-protein complexes
called spikes（刺突）.
5. Viruses without envelopes are called naked viruses.
GENERAL MORPHOLOGY
1. Helical （螺旋对称）viruses (for example, tobacco mosaic virus)
resemble long rods, and their capsids are hollow cylinders surrou
nding the nucleic acid.
2. Polyhedral（多面体） viruses (for example, adenovirus，腺病毒)
are many sided. Usually the capsid is an icosahedron（二十面体）.
Enveloped viruses are covered by an envelope and are roughly sph
erical but highly pleomorphic（多型性的）. There are also envelo
ped helical viruses (for example, influenza virus) and enveloped
polyhedral viruses (for example, herpes simplex virus).
3. Complex viruses have complex structures. For example, many bacter
iophages have a polyhedral capsid with a helical tail attached.
Taxonomy of Viruses
1. Classification of viruses is based on type of nucleic acid, morpho
logical class, size of capsid, and number of capsomeres.
2. Other classification schemes take into account the virus's susc
eptibility to microbial control agents, immunological properties,
site of multiplication, and method of transmission.
Isolation, Cultivation, and Identification of Viruses
1.
2.
Viruses must be grown in living cells.
The easiest viruses to grow are bacteriophages.
GROWTH OF BACTERIOPHAGES IN THE LABORATORY
The plaque method：
1.
Mixes bacteriophages with host bacteria and nutrient agar.
2.
After several viral multiplication cycles, the bacteria in the a
rea surrounding the original virus are destroyed; the area of l
ysis is called a plaque.
3.
Each plaque can originate with a single viral particle or with mo
re than one; the concentration of viruses is given as plaque-formi
ng units.
GROWTH OF ANIMAL VIRUSES IN THE LABORATORY
1. Cultivation of some animal viruses requires whole animals.
2. Some animal viruses can be cultivated in embryonated eggs.
3. Cell cultures are cells growing in culture media in the laborato
ry.
4. Viral growth can cause cytopathic effects in the cell culture.
VIRAL IDENTIFICATION
1. Serological tests are used most often to identify viruses. Viruses
may be identified by restriction enzyme fragments and nucleic acid
base sequencing.
2. Viral Multiplication
1. Viruses do not contain enzymes for energy production or protein
synthesis.
2. For a virus to multiply, it must invade a host cell and direct
the host's metabolic machinery to produce viral enzymes and co
mponents.
MULTIPLICATION OF BACTERIOPHAGES
T-Even Bacteriophages
1. The T-even bacteriophages that infect E coli have been studied e
xtensively.
2. In attachment, sites on the phage's tail fibers attach to comp
lementary receptor sites on the bacterial cell.
3. In penetration, phage lysozyme opens a portion of the bacteria
l cell wall, the tail sheath contracts to force the tail core th
rough the cell wall, and phage DNA enters the bacterial cell. T
he capsid remains outside.
4. In biosynthesis, transcription of phage DNA produces mRNA codin
g for proteins necessary for phage multiplication. Phage DNA is re
plicated, and capsid proteins are produced. During the eclipse
period, separate phage DNA and protein can be found.
5. During maturation, phage DNA and capsids are assembled into com
plete viruses.
6. During release, phage lysozyme breaks down the bacterial cell wa
ll, and the multiplied phages are released.
7. The time from phage adsorption to release is called burst time (2
0 to 40 minutes). Burst size, the number of newly synthesized phag
es produced from a single infected cell, ranges from 50 to 200.
Lysogeny
1. During a lytic cycle, a phage causes the lysis and death of a ho
st cell.
2. Some viruses can either cause lysis or have their DNA incorpora
ted as a prophage into the DNA of the host cell. The latter si
tuation is called lysogeny.
3. Prophage genes are regulated by a represser coded for by the p
rophage. The prophage is replicated each time the cell divides.
4. Exposure to certain mutagens can lead to excision of the prophage
and initiation of the lytic cycle.
5. Because of lysogeny, lysogenic cells become immune to reinfection
with the same phage, and the host cell can exhibit new propert
ies.
6. A lysogenic phage can transfer bacterial genes from one cell to a
nother through transduction. Any genes can be transferred in ge
neralized transduction,
and specific genes can be transferred
in specialized transduction.
MULTIPLICATION OF ANIMAL VIRUSES
Animal viruses attach to the plasma membrane of the host cell.
1. Penetration of enveloped viruses occurs by endocytosis.
2. Animal viruses are uncoated by viral or host cell enzymes. Th
e DNA of most DNA viruses is released into the nucleus of the ho
st cell. Transcription of viral DNA and translation produce vir
al DNA and, later, capsid protein. Capsid protein is synthesize
d in the cytoplasm of the host cell.
3. Retroviruses carry reverse transcriptase (RNA-dependent DNA po
lymerase), which transcribes DNA from RNA.
4. After maturation, viruses are released. One method of release
(and envelope formation) is budding. Naked viruses are release
d through ruptures in the host cell membrane.
Effects of Animal Viral Infection on Host Cells
1. Cytopathic effects (CPE) are abnormalities that lead to damage
or death of a host cell.
2. Cytopathic effects include inclusion bodies, polykaryocytes, an
d altered function.
Interferon
Interferon is produced by virus-infected cells and protects neigh
boring cells from viral infection.
Viruses and Diseases
Viruses cause a variety of diseases among all groups of living organisms. V
iral diseases include the flu, common cold, herpes, measles, chicken pox, small
pox, and encephalitis. Antibiotics are not effective against viruses. Vaccinat
ion offers protection for uninfected individuals.
Emergent Viruses
Viruses are usually quite specific as to their hosts and even to the types
of cells they infect in a multicellular host. Recently some viruses appear to h
ave shifted their host: HIV, hantavirus, and ebola appear to be either viruses
shifting to a new (human) host or else viruses whose existence and effects are
just now being realized by scientists and the general public.
Viruses and Cancer
1. An excess of tissue due to unusually rapid cell multiplication
is called a tumor. Tumors are malignant (cancerous) or benign (n
oncancerous). Metastasis refers to the spread of cancer to othe
r parts of the body.
2. Tumors are usually named by attachment of the suffix oma to th
e name of the tissue from which the tumor arises.
3. The earliest relationship between cancer and viruses was demonst
rated in the early 1900s, when chicken leukemia and chicken sarco
ma were transferred to healthy animals by cell-free filtrates.
TRANSFORMATION OF NORMAL CELLS INTO TUMOR CELLS
1. Eucaryotic cells have proto-oncogenes that code for proteins nec
essary for the cells' normal growth. When activated to oncogenes,
these genes transform normal cells into cancerous cells.
2. Viruses capable of producing tumors are called oncogenic virus
es.
3. Several DNA viruses and retroviruses are oncogenic.
4. The genetic material of oncogenic viruses becomes integrated int
o the host cell's DNA.Transformed cells lose contact inhibition,
contain virusspecific antigens (TSTA and T antigen), exhibit chr
omosomal abnormalities, and can produce tumors when injected in
to susceptible animals.
ACTIVATION OF ONCOGENES
A single mutation can result in the production of a protein require
d for transformation.
1. Transduction of oncogenes could result in oncogene products
being made in abnormal amounts or at the wrong time.
2. Translocation of oncogenes could remove normal controls.
3. Gene amplification causes unusually large amounts of oncogene
products.
DNA-CONTAINING ONCOGENIC VIRUSES
1. Oncogenic viruses are found among adenoviruses, hepesviruses,
poxviruses, and papovaviruses.
2. The EB virus, a herpesvirus, causes infectious mononu cleosis a
nd has been implicated in Burkitt's lymphoma
and nasopharyngeal carcinoma. One type of herpes simplex virus
(HHV 2), associated with over 90% of genital
herpes infections, might be implicated in cervical cancer.
RNA-CONTAINING ONCOGENIC VIRUSES
1. Among the RNA viruses, only retroviruses seem to be oncogenic.
2. HTLV 1 and HTLV 2 have been associated with human leukemia and
lymphoma.
3. The virus's ability to produce tumors is related to the prod
uction of reverse transcriptase. The DNA synthe sized from the
viral RNA becomes incorporated as a provirus into the host c
ell's DNA.
Plant Viruses
Plant viruses must enter plant hosts through wounds or with invasi
ve parasites, such as insects.
Viroids and Prions
Viroids are common plant pathogens which are a serious economic prob
lem.
The RNA genomes of viroids are 246-375 nucleotides in length and share many sim
ilarities:

They are all single stranded covalent circles

There is extensive intramolecular base pairing

A DNA-directed RNA polymerase makes both plus and minus strands

Replication does not depend on the presence of a helper virus

No proteins are encoded
Virusoids and Satellites
Virusoids or satellite RNAs are also several hundred nucleotides long
circular and single stranded. They depend on a helper virus for repl
ication.
Chapter 4 virus
review questions
1. Viruses were first detected because they are filterable. What d
o we mean by the term filterable, and how could this property hav
e helped their detection before invention of the electron microsc
ope?
2. Why do we classify viruses as obligatory intracellular parasite
s?
3. List the four properties that define a virus. What is a virio
n?
4. Describe the three morphological classes of viruses, then diagram
and give an example of each.
5. Describe how bacteriophages are detected and enumerated by the
plaque method.
6. Describe the multiplication of a T-even bacteriophage. Be sure to
include the essential features of attachment, penetration, biosyn
thesis, maturation, and release.
7. Recall from Chapter 1 that Koch's postulates are used todetermine
the etiology of a disease. Why is it difficult to determine the et
iology of a viral infection such as influenza?
8. Assume that this strand of RNA is the nucleic acid for an RNA-con
taining animal virus: UAGUCAAGGU.
(a) Describe the steps of RNA replication for a virus that contain
s a + strand of RNA.
(b) Describe the steps of RNA replication for a virus that contain
s a - strand of RNA.
(c) Describe the steps of RNA replication for a virus that contain
s double-stranded RNA.
(d) Describe the steps of RNA replication for a virus that contain
s reverse transcriptase.
9.
In some viruses, capsomeres function as enzymes as well as s
tructural supports. Of what advantage is this to the virus.
10. Prophages and proviruses have been described as being similar t
o bacterial plasmids. What similar properties do they exhibit? Ho
w are they different?
Chapter5 nurtution of microbes
第 5 章 微生物的营养
CHEMICAL REQUIREMENTS
1. Microorganisms require a carbon source; chemoheterotrophs use a
n organic molecule, and autotrophs typcally use carbon dioxide.
2. Nitrogen is needed for protein and nucleic acid synthesis. Nitro
gen can be obtained from decomposition of proteins or from NH4+ or
NO3-; a few bacteria are able to fix N2.
3. Water is also necessary to the growth of all microorganisms.
4. Other chemicals required for microbial growth include iroganic s
alt(sulfur, phosphorus, and some trace elements), and, for some micr
oorganisms, organic growth factors.
MOVEMENT OF MATERIALS ACROSS MEMBRANES
1. 1Movement across the membrane may be by passive processes, in w
hich materials move from higher to lower concentration and no
energy is expended by the cell.
2. In simple diffusion, molecules and ions move until equilibrium i
s reached.
3. In facilitated diffusion, substances are transported by perme
ases across membranes from high to low concentration.
4. Osmosis is the movement of water from high to low concentration
across a selectively semipermeable membrane until equilibrium is
reached.
5. In active transport, materials move from low to high concent
rations by permeases, and the cell must expend energy.
6. In group translocation, energy is expended to modify chemical
s and transport them across the membrane.
Culture Media
1. A culture medium is any material prepared for the growth of
bacteria in a laboratory.
2. Microbes that grow and multiply in or on a culture medium are
known as a culture.
3. Agar is a common solidifying agent for a culture medium.
CHEMICALLY DEFINED MEDIA
A chemically defined medium is one in which the exact chemical com
position is known.
COMPLEX MEDIA
1. A complex medium is one in which the exact chemical compositio
n is not known.
ANAEROBIC GROWTH MEDIA AND METHODS
1. Reducing media chemically remove molecular oxygen
2. Petri plates can be incubated in an anaerobic jar or anaero
bic glove box.
SPECIAL CULTURE TECHNIQUES
1. Some parasitic and fastidious bacteria must be cultured in livi
ng animals or in cell cultures.
1. CO2 incubators or candle jars are used to grow bacteria requiring
an increased CO2 concentration.
SELECTIVE AND DIFFERENTIAL MEDIA
1. By inhibiting unwanted organisms with salts, dyes, orother
chemicals, selective media allow growth of only the desired
microbe.
2.
Differential media are used to distinguish between differen
t organisms.
ENRICHMENT CULTURE
An enrichment culture is used to encourage the growth of a partic
ular microorganism in a mixed culture.
Trace Elements
Microbes require very small amounts of other mineral elements, suc
h as iron, copper, molybdenum, and zinc; these are referred to as
trace elements. Most are essential for activity of certain enzymes,
usually as co-factors. Although these components are sometimes ad
ded to a laboratory medium, they are usually assumed to be natural
ly present in tap water and other components of media. Even most d
istilled waters contain adequate amounts, but tap water is sometim
es specified to ensure that these trace minerals will be present i
n culture media.
●What advantages do solid media offer for the culture of microorgani
sms?
●What is the enrichment culture technique and why was it a useful new
method in microbiology?
GLOSSARY
（常用微生物学专业名词词汇表）
active immunity（主动免疫）: Immunity acquired through direct stimulat
ion of the immune system by antigen.
active transport（主动运输）:Transport of molecules against a concent
ration gradient (from regions of low concentration to regions of high
concentration) with the aid of proteins in the cell membrane and ene
rgy from ATP.
Alcohol fermentation（乙醇发酵）：is the formation of alcohol from sugar. Yeast,
when under anaerobic conditions, convert glucose to pyruvic acid via the glyco
lysis pathways, then go one step farther, converting pyruvic acid into ethanol,
a C-2 compound.
aerobe（好氧微生物）: A microorganism that lives and grows in the pres
ence of free gaseous oxygen (O2).
aflatoxin（黄曲霉毒素）: From Aspergillus flavus t, a mycotoxin that
typically poisons moldy animal feed and can cause liver cancer in hum
ans and other animals.
AIDS（爱滋病）: Acquired Immune deficiency syndrome. The complex of si
gns and symptoms characteristic of the late phase of human immunodefi
ciency virus (HIV) infection.
Ames test（艾姆氏实验）: A method for detecting mutagenic and potenti
ally carcinogenic agents based upon the genetic alteration of nutriti
onally defective bacteria
anabolism（合成代谢）: The energy consuming process of incorporating
nutrients into protoplasm through biosynthesis.
anaerobe（厌氧微生物）: A microorganism that grows best, or exclusive
ly, in the absence of oxygen.
antibiotic（抗生素）:A chemical substance from one microorganism that
can inhibit or kill another microbe even in minute amounts.
antibody（抗体）: A large protein molecule evoked in response to an a
ntigen that interacts specifically with that antigen.
antigen（抗原）: Any cell, particle, or chemical that induces a speci
fic immune response by B cells or T cells and can stimulate resistanc
e to an infection or a toxin.
antigenic determinant（抗原决定基）:The precise molecular group of an
antigen that defines its specificity and triggers the immune respons
e.
antimetabolite（抗代谢物）:A substance such as a drug that competes w
ith, substitutes for, or interferes with a normal metabolite.
antiseptic（防腐剂）：A growth-inhibiting agent used on tissues to pr
event infection.
antiserum（抗血清）：Antibody-rich serum derived from the blood of a
nimals (deliberately immunized against infectious or toxic antigen)
or from people who have recovered from specific nfections.
antitoxin（抗毒素）：Globulin fraction of serum that neutralizesa spe
cific toxin. Also refers to the specific antitoxin antibody itself.
arthrospore（节孢子）：A fungal spore formed by the septation fragment
ation of hyphae.
ascospore（子囊）：A spore formed within a saclike cell (ascus) of Asc
omycota following nuclear fusion and meiosis.
asepsis（无菌）：A condition free of viable pathogenic microorganisms.
autoantibody（自身抗体）：An "anti-self antibody having an ffinity f
or tissue antigens of the subject in which it is formed.
autoantigen（自身抗原）： Molecules that are inherently part of self
but are perceived by the immune system as foreign
autoimmune disease（自身免疫疾病）：The pathologic condition arising
from the production of antibodies against autoantigens. Example: rheu
matoid arthritis. Also called autoimmunity
bacteriophage（噬菌体）：A virus that specifically infects bacteria.
bacteriostatic（抑菌）：Any process or agent that inhibits bacterial
growth.
binary fission（二分裂）：The formation of two new cells of approxima
tely equal size as the result of parent cell division.
B lymphocyte (B cell)： A white blood cell that gives rise to plasma
cells and antibodies.
broad spectrum（广谱）： A word to denote drugs that affect many diff
erent types of bacteria, both gram-positive and gram-negative.
Capsid（衣壳）：The protein covering of a virus's nucleic acid core.
Capsids exhibit symmetry due to the regular arrangement of subunits c
alled capsomers.
capsomer（衣壳粒）： A subunit of the virus capsid shaped as a triang
le or disc.
capsule（荚膜）： In bacteria, the loose, gel-like covering or slime
made chiefly of simple polysaccharides. This layer is protective and
can be associated with virulence.
Catabolism（分解代谢）：The chemical breakdown of complex compounds in
to simpler units to be used in cell metabolism.
cell-mediated immune（细胞介导免疫）： The type of immune responses b
rought about by T cells, such as cytotoxic, suppressor, and helper ef
fects.
chemoautotroph（化能自养菌）：An organism that relies upon inorganic c
hemicals for its energy and carbon dioxide for its carbon. Also calle
d a chemolithotraph
chemotaxis（趋化性）： The tendency of organisms to move in response t
o a chemical gradient (toward an attractant or to avoid adverse stimu
li).
Chemotherapy（化学治疗剂）：The use of chemical substances or drugs to
treat or prevent disease.
Chitin（几丁质）：A polysaccharide similar to cellulose in chemical st
ructure. This polymer makes up the homy substance of the exoskeletons
of arthropods and certain fungi
complement（补体）：In immunology, serum protein components hat act i
n a definite sequence when set in motion either by an antigen-antibod
y complex or by factors of the alternative (properdin) pathway.
Conldia（分生孢子）：Asexual fungal spores shed as free units from th
e tips of fertile hyphae. Conjugation（接合）：In bacteria, the conta
ct between donor and recipient cells associated with the transfer of
genetic material such as plasmids. Can involvespecial (sex) pili. Als
o a form of sexual recombination in ciliated protozoans.
Colony(菌落)： A macroscopic cluster of cells appearing on a solid me
dium, each arising from the multiplication of a single cell.
Contaminant（污染物）：An impurity; any undesirable material or organ
ism.
Culture（培养物）：The visible accumulation of microorganisms in or o
n a nutrient medium. Also, the propagation of microorganisms with var
ious media. curd
differential medium（鉴别培养基）： A single substrate that discrimina
tes between groups of microorganisms on the basis of differences in t
heir appearance due to different chemical reactions.
differential stain（鉴别染色）： A technique that utilizes two dyes t
o distinguish between different microbial groups or cell parts by col
or reaction.
Disinfection（消毒）：The destruction of pathogenic nonsporulating m
icrobes or their toxins, usually on inanimate surfaces.
ELISA（酶联免疫）： Abbreviation for enzyme-linked immunosorbent assa
y, a very sensitive serological test used to detect antibodies in dis
eases such as AIDS。
endospore（芽孢）： A small, dormant, resistant derivative of a bacte
rial cell that germinates under favorable growth conditions into a ve
getative cell. The bacterial genera Bacillus and Clostridiim are typ
ical sporeformers.
endotoxin（内毒素）： A bacterial intracellular toxin that is not ord
inarily released (as is exotoxin). Endotoxin is composed of a phospho
lipid-polysaccharide complex that is an integral part of gram-negativ
e bacterial cell walls. Endotoxins can cause severe shock and fever.
enriched medium（加富培养基）： A nutrient medium supplemented with b
lood, serum, or some growth factor to promote the multiplication of f
astidiousmicroorganisms.
enveloped virus（包膜病毒）：A virus whose nucleocapsid is enclosed b
y a membrane derived in part from the host cell. It usually contains
exposed glycoprotein spikes specific for the virus. essential nutrien
t（必须营养）：Any ingredient such as a certain amino acid, fatty aci
d, vitamin, or mineral that cannot be formed by an organism and must
be supplied in the diet. A growth factor. eucaryotic cell（真核细胞）：
A cell that differs from a procaryotic cell chiefly by having a nu
clear membrane (a well-defined nucleus), membrane-bound subcellular
organdies, and mitotic cell division.
Exotoxin（外毒素）：A toxin (usually protein) that is secreted and ac
ts upon a specific cellular target. Examples: botulin, tetanospasmin,
diphtheria toxin, and erythrogenic toxin.
Facultative（兼性的）：Pertaining to the capacity of microbes to adapt
or adjust to variations; not obligate. Example: The presence of oxyg
en is not obligatory for a facultative anaerobe to grow.
Fermentation（发酵）：The extraction of energy through anaerobic degr
adation of substrates into simpler, reduced metabolites. In large indu
strial processes, fermentation can mean any use of microbial metabolis
m to manufacture organic chemicals or other products.
Flagellum（鞭毛） -- Hair-like structure attached to a cell, used for
locomotion in many protists and prokaryotes. The prokaryotic flagellu
m differs from the eukaryotic flagellum in that the prokaryotic flage
llum is a solid unit composed primarily of the protein flagellin, whi
le the eukaryotic flagellum is composed of several protein strands bo
und by a membrane, and does not contain flagellin. The eukaryotic fla
gellum is sometimes referred to as an undulipodium.
Genotype（表型）：The genotype is ultimately responsible for an organis
m's phototype, or expressed characteristics.
Glycolysis（糖酵解）：The energy-yielding breakdown (fermentation) of
glucose to pyruvic or lactic acid. It is often called anaerobic glycol
ysis because no molecular oxygen is consumed in the degradation.
Gram stain（革兰氏染色）：A differential stain for bacteria useful in i
dentification and taxonomy. Gram-positive organisms appear purple from
crystal violet-mordant retention; whereas gram-negative organisms appear
red after loss of crystal violet and absorbance of the safranin counter
stain.
Granulocyte（粒细胞）：A mature leukocyte that contains noticeabte gran
ules in a Wright stain. Examples: neutrophils, eoainophils, and basophil
s.
growth factor（生长因子）： An organic compound such as a vitamin or am
ino acid that must be provided in the diet to facilitate growth. An esse
ntial nutrient.
Halophlle（嗜盐菌）： A microbe whose growth is either stimulated by sa
lt or requires a high concentration of salt for growth.
H antigen（H-抗原）： The flagellar antigen of motile bacteria. H comes
from the German word hauch that denotesthe appearance of speading growt
h on solid.
helper T cell（辅助 T-细胞）：A class of thymus-atimulated lymphocyte
s that facilitate various immune activities such as assisting B cells a
nd macrophages. Also called a T helper cell.
Heterotroph（异养菌）： An organism that relies upon organic compounds
for its carbon and energy needs.
Immunity（免疫）：An acquired resistance to an infectious agent due to
prior contact with that agent.
immunogen（免疫原）： Any substance that induces a state of sensitivit
y or resistance after processing by the immune system of the body.
immune system（免疫系统）：One of the eleven major body organ systems
in vertebrates; defends the internal environment against invading mic
roorganisms and viruses and provides defense against the growth of ca
ncer cells.
immunoglobulin（免疫球蛋白）： The chemical class of proteins to which
antibodies belong.
Inclusion（内含物）： A relatively inert body in the cytoplasm such as
storage granules, glycogen, fat, or some other aggregated metabolic
product.
Infection（感染）： The entry, establishment, and multiplication of p
athogenic organisms within a host.
infectious disease（感染性疾病）： The state of damage or toxicity in
the body caused by an infectious agent.
Inflammation（发炎）： A natural, nonspecific response to tissue inju
ry that protects the host from further damage. It stimulates immune r
eactivity and blocks the spread of an infectious agent.
Inoculation（接种）： The implantation of microorganisms into or upon
culture media.
Interferon（干扰素）： Naturally occurring polypeptides produced by f
ibroblasts and lymphocytes that can block viral replication and regul
ate a variety of immune reactions.
Isolation（分离）： The separation of microbial cells by serial diluti
on or mechanical dispersion on solid media to achieve a clone or pure
culture.
Latency（潜伏）： The state of being inactive. Example: a latent viru
s or latent infection.
L form（L-型菌）： L-phase variants; wall-less forms of some bacteria
that are induced by drugs or chemicals.
Lipopolysaccharide（脂多糖，LPS）： A molecular complex of lipid and
carbohydrate found in the bacterial cell wall. The lipopolysaccharide
(LPS) of gram-negative bacteria is an endotoxin with generalized pat
hologic effects such as fever
Lysis（溶解）： The physical rupture or deterioration of a cell.
Lysogeny（溶原性）： The indefinite persistence of bacteriophage DNA i
n a host without bringing about the production of virions. A lysogeni
c cell can revert to a lytic cycle, the process that ends in lysis.
lysosome （溶酶体）：A cytoplasmic organelle containing lysozyme and
other hydrolytic enzymes. lysozyme（溶菌酶）： An enzyme that attacks
the bonds on bacterial peptidoglycan. It is a natural defense found i
n tears and saliva.
macrophage A while blood cell derived from a monocyte that leaves th
e circulation and enters tissues. These cells are important in nonspe
cific
mixed culture（混合培养）： A container growing two or more different,
known species of microbes.
monoclonal antibody（单克隆抗体）： An antibody produced by a clone o
f lymphocytes that respond to a particular antigenic determinant and
generate identical antibodies only to that determinant.
Monocyte（单核细胞）： A large mononuclear leukocyte normally found i
n the lymph nodes, spleen, bone marrow, and loose connective tissue.
This type of cell makes up 3% to 7% of circulating leukocytes.
Mutagen（诱变剂）：Any agent that induces genetic mutation. Examples:
certain chemical substances, ultraviolet，light, radioactivity.
Mutation（突变）： A permanent inheritable alteration in the DNA sequ
ence or content of a cell. Mycelium（菌丝体）： The filamentous mass
that makes up a mold. Composed of hyphae.
narrow spectrum（窄谱）： Denotes drugs that are selective and limite
d in their effects. For example, they inhibit either gram-negative or
gram-positive bacteria, but not both.
negative stain（负染色）：A staining technique that renders the back
ground opaque or colored and leaves the object unstained so that it i
s outlined as a colorless area
nitrogen fixation（固氮）：A process occurring in certain bacteria in
which atmospheric Na gas is converted to a form (NH^ usable by plant
s.
Nucleocapsid（核衣壳）： In viruses, the close physical combination o
f the nucleic acid with its protective covering.
Nucleoid（拟核）：The basophilic nuclear region or nuclear body that
contains the bacterial chromosome.
Nutrient（营养物质）：Any chemical substance that must be provided to
a cell for normal metabolism and growth. Macronutrients are required
in large amounts, and micronutrients in small amounts.
Obligate（专性的）： Without alternative; restricted to a particular
characteristic. Example: An obligate parasite survives and grows only
in a host; an obligate aerobe must have oxygen to grow; an obligate
anaerobe is destroyed by oxygen.
Parasite（寄生）： An organism that lives on or within another organi
sm (the host), from which it obtains nutrients and enjoys protection.
The parasite produces some degree of harm in the host indirectly by
donation of preformed immune substances (antibodies) produced in the
body of another Individual.
Pasteurization（巴斯德消毒）： Heat treatment of perishable fluids su
ch as milk, fruit juices, or wine to destroy heat-sensitive vegetative
cells, followed by rapid chilling to inhibit growth of survivors and
germination of spores. It prevents infection and spoilage.
Pathogen（病原体）：Any agent, usually a virus, bacterium, fungus, pro
tozoan, or helminth, that causes disease.
Saprophytes(腐生型) Organisms that obtain their nutrients from decaying plants
and animals. Saprophytes are important in recycling organic material.
Pathogenidty（致病性）：The capacity of microbes to cause disease.
Pathology（病原学）：The structural and physiological effects of dise
ase on the body.
passive transport（被动扩散）Diffusion across a plasma membrane in wh
ich the cell expends no energy.
Penicillins（青霉素）：A large group of naturally occurring and synthe
tic antibiotics produced by penicillium mold and active against the ce
ll wall of bacteria.
Peptidoglycan(肽聚糖)： A network of polysaccharide chains cross-link
ed by short peptides that forms the rigid part of bacterial cell walls.
Gram-negative bacteria have a smaller amount of this rigid structure
than do gram-positive bacteria.
Plasmids（质粒）Self-replicating, circular DNA molecules found in bac
terial cells; often used as vectors in recombinant DNA technology. Sm
all circles of double-stranded DNA found in some bacteria. Plasmids c
an carry from four to 20 genes. Plasmids are a commonly used vector i
n recombinant DNA studies.
periplasmic space（周质空间）：The region between the cell wall and c
ell membrane of the cell envelopes of gram-negative bacteria.
Phage（噬菌体）：A bacteriophage; a virus that specifically parasitize
s bacteria.
Phenotype（表型）： The observable characteristics of an organism pro
duced by the interaction between its genetic potential (genotype) and
the environment.
Photoautotroph（光能自养菌）： An organism that utilizes light fails e
nergy and carbon dioxide chiefly for its' carbon needs.
Pilus（性丝） Projection from surface of a bacterial cell (F+) that c
an donate genetic material to another (F-).
prokaryote cell（原核细胞）： A small, simple cell lacking a true nu
cleus, a nuclear envelope, and membrane-enclosed organelles
prophage（前噬菌体）：A lysogenized bacteriophage; a phage that is la
tently incorporated into the host chromosome instead of undergoing,
viral replication and lysis. prophylactic Any device, method, or sub
stance used to prevent disease.
Protoplast（原生质体）：A bacterial cell whose cell wall is completel
y kicking and that is vulnerable to osmotic lysis.
Pseudohypha（假菌丝）：A chain of easily separated, spherical to saus
age-shaped yeast cells partitioned by constrictions rather than by se
pta.
Psychrophile（嗜冷菌）：A microorganism that thrives at low temperatu
re (0°-20°C), with a temperature optimum of 0°-15°C.
respiratory chain（呼吸链）：In cellular respiration, a series of e
lectron-carrying molecules that transfers energy-rich electrons and p
rotons to molecular oxygen. In transit, energy is extracted and conse
rved in the form of ATP.
reverse transcriptase（逆转录酶）：The enzyme possessed by retrovirus
es that carries out the reversion of RNA to DNA—a form of reverse tran
scription.
SCP（单细胞蛋白）：Abbreviation for single-cell protein, a euphemisti
c expression for microbial protein intended for human and animal consu
mption..
selective media（选择培养基）： Nutrient media designed to favor the gr
owth of certain microbes and to inhibit.
Serotyping（血清型）：The subdivision of a species or subspecies into
an immunologic type, based upon antigenic characteristics.
sexual reproduction（有性繁殖）A system of reproduction in which two
haploid sex cells fuse to produce a diploid zygote.
Spheroplast（球形体）： A gram-negative cell whose peptidoglycan, when
digested by lysozyme,
remains intact but is osmotically vulnerable
spike（刺突）：A receptor on the surface of certain enveloped viruses
that facilitates specific attachment to the host cell.
Spirillum（螺菌）：A type of bacterial cell with a rigid spiral shape
and external flagella.
Spirochete（螺旋体）：A coiled, spiral-shaped bacterium that has endo
flagella and flexes as it moves.
Sporangium（孢囊）：A fungal cell in which asexual spores are formed
by multiple cell cleavage. Sterilization（灭菌）：Any process that com
pletely removes or destroys all viable microorganisms, including viru
ses, from an object or habitat. Material so treated is sterile.
Strain（菌株）：In microbiology, a set of descendants cloned from a c
ommon ancestor that retain the original characteristics. Any deviatio
n from the original is a different strain.
subcellular vaccine（亚单位疫苗）： A vaccine against isolated microbi
al antigens rather than against the entire organism.
superoxide ion（超氧离子）： A toxic radical form oxygen metabolism
suppressor T cell（抑制 T 细胞）：A class of T cells that inhibits the a
ctions of B cells and other T cells.
temperate phage（温和噬菌体）：A bacteriophage that enters into a less
virulent state by becoming incorporated into the host genome as a pro
phage instead of in the vegetative or lytic form that eventually dest
roys the cell.
thermal death point（致死温度）：The lowest temperature that achieves s
terilization in a given quantity of broth culture upon a 10-minute ex
posure. Examples:55°C for Escherichia coil. 60°C for
Mycobaaerium tuberculosis, and 120°C for spores.
thermal death time( 热致死时间)：The least time required to kill all cel
ls of a culture at a specified temperature.
Therrnophlle（嗜热菌）：A microorganism that thrives at a temperature of
50°C or higher.
T lymphocyte (T cell)：A white blood cell that is processed in the th
ymus gland and is involved in cell-mediated immunity.
Toxoid（类毒素）：A toxin that has been rendered nontoxic but is still
capable of eliciting the formation of protective antitoxin antibodie
s; used in vaccines.
Transduction（转导）：The transfer of genetic material from one bacte
rium to another by means of a bacteriophage vector.
Transformation（转化）：In microbial genetics, the transfer of genet
ic material contained in "naked" DNA fragments from a donor cell to a
competent recipient cell.
Transposon（转座）：A DNA segment with an insertion sequence at each
end, enabling it to migrate to another plasmid, to the bacterial chro
mosome, or to a bacteriophage.
Vaccine（免疫法）：Originally used in reference to inoculation with t
he cowpox or vaccinia virus to protect against smallpox. In general,
the term now pertains to injection of whole microbes (killed or atten
uated), toxoids, or parts of microbes as a prevention or cure for dis
ease.
Virold（类病毒）：An infectious agent that, unlike a virion, lacks a
capsid and consists of a closed circular RNA molecule. Although known
viroids are all plant pathogens, it is conceivable that animal versi
ons exist.
Zygospore（接合孢子）：A thick-walled sexual spore produced by the zy
gomycete fungi. It develops from the union of two hyphae, each bearin
g nuclei of opposite mating types.