Post Lab Pure Culture Isolation Flashcards
(129 cards)
is the process of preserving the integrity and functionality of cells, tissues, and organs held
outside the native environment for extended storage times
biopreservation
The primary aim of culture preservation is to
maintain
the organism alive, uncontaminated, and without variation
or mutation, that is, to preserve the culture in a condition
that is as close as possible to the original isolate
in fact, some strains of the same species give ____results
with the same procedure
variable
It should be emphasized that the
success of any preservation method depends on the use of
the appropriate medium and cultivation procedure and on
the age of the culture at the time of preservation. This is
particularly true when working with bacteria that contain
___ or ____ ___or that exhibit growth
phases such as morphogenesis or spore formation
plasmids
recombinant DNA
It should be emphasized that the
success of any preservation method depends on the use of
the appropriate medium and cultivation procedure and on
the age of the culture at the time of preservation. This is
particularly true when working with bacteria that contain
plasmids or recombinant DNA or that exhibit growth
phases such as ____or ________
morphogenesis
spore formation
is an important and often neglected aspect of stock culture maintenance. Too often, isolates are
not given strain designations or, if they are, the designations
are not documented in strain data files
record keeping
) refers to a specific strain with distinct phenotypic characteristics which should be recorded
strain designation
The traditional method of preserving bacterial cultures is by
periodic serial transfer to fresh medium
The major disadvantages of the ____ technique are the risks of
contamination, transposition of strain numbers or designations (mislabeling), selection of variants or mutants, and
possible loss of culture, as well as the required storage space.
serial transfer technique
Three conditions must be determined when using this
method for the preservation of cultures:
serial culture technique
uitable maintenance medium
ideal storage temperature
frequency
between transfers
is not recommended as a longterm preservation method.
subculturing
are preferred for subculturing because they
lower the metabolic rate of the organism and thus prolong the period between transfers.
minimal media
When a complex
medium is used, more ____transfers may be necessary as
a result of accelerated growth or metabolite accumulation
frequent
A variety of bacteria, including members of the Archaea
(11, 19, 21, 29), have been preserved by subculturing in
biphasic (liquid-solid) medium
is the preferred method
for subculture is storage in a ___
refrigerator
; however, if refrigeration presents a problem,
the simplest method is storage at r
room temperature in a test tube rack or specially constructed box containing shelves with holes
Cultures stored in this
fashion require constant care since they tend to dry quickly
and, unless the laboratory has a controlled environment,
are subject to ___fluctuations.
temperature
To minimize dehydration, use screw caps with rubber liners, wrap the tube caps in ____
parafilm
Do not
select single colonies in transferring cultures, since the chances
of selecting a mutant are greater when this technique is
used.
what preservation method
serial transfer
Many bacterial species can be successfully preserved for
months (or years) simply by immersing in a ___
sterile medicinal grade oil
type of oil with a specific gravity of
0.865 to 0.890 is also satisfactory (16).
paraffin oil
Sterilize 5 ml of oil per Pyrex test tube (18 by 150 mm),
sealed with a metal or other heat-resistant closure by what sterilization technique
dry heat
Contamination of cultures when this method is used is often due
to improperly sterilized mineral oil. Each lot of sterilized oil
must be tested for sterility by streaking on an appropriate
medium such as
nutrient agar
trypticase soy agar (TSA)
After growth reaches late
___ phase or ____occurs, add the sterile mineral oil aseptically to a depth of at least 2 cm (a slant must
be entirely covered) to prevent dehydration and to reduce
metabolic activity and growth of the culture (16, 33).
logarithmic
sporulation
