Word - sserc

muskrateurekaΒιοτεχνολογία

12 Φεβ 2013 (πριν από 4 χρόνια και 8 μήνες)

142 εμφανίσεις

Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide





5
-
14 Microbiology






Technical Guide




Trial Materials




Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



IMPROVING SCIENCE EDUCATION 5

14 PROJECT

PRACTICAL ACTIVITIES
-

MICROBIOLOGY


Technical Information

Since working with micro
-
organisms is covered by the COSHH regulations, it is
necessar
y to have suitable and sufficient control measures in place which have been
developed as a result of assessing the risks involved. An appropriate code of practice
on Safety in Microbiology can be adopted to meet the requirements. These practicals
have bee
n developed to satisfy the Code of Practice for Microbiology Safety and
Techniques originated by Strathclyde Regional Council and published in an extensively
revised edition by SSERC, 2002.


LOOKING AT MICRO
-
ORGANISMS


Practical: Life in the Littlest Loch

-

Looking at Algae and Protozoa


Materials


Per group


Beaker with a little water


Petri dish containing 2 glass microscope slides

(and, possibly, coverslips
-

optional see Pupil Guide)

2 x 1cm
3

pipettes


Clear film can lid


Clear sellotape and scissor
s



Hand lens and microscope

Discard jar containing 1% Virkon




To share


Mixed protozoa

Mixed algae

Paper towels

Lens tissue


Notes


The use of coverslips requires care. They can be awkward for pupils to handle and are
hazardous if broken when slivers o
f fine glass may get under fingernails. The use of
coverslips can be avoided, at least for the first part of the practical, by using two thin
slides instead of a slide and coverslip (e.g. Scientific Lab Supplies reference MIC3004,
which are 0.6


0.8 mm t
hick as against the standard 1 mm thickness). The need for
thin slides arises because of the decreasing depth of focus with increasing
magnification of the objective used. Clear film can lids can be obtained from chemist
shops which process films. On requ
est, they are usually happy to collect them for you.

Mixed algal cultures and protozoan cultures are available from
Sciento

as well as from
Blades Biological

(see Address List), We’ve found the cultures from the former to be
consistently of high quality.







cont./over


Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



Sciento’s kits of dormant protist cysts (catalogue ref. PK5) are a particularly convenient
way of obtaining a mix of protozoans. Living specimens can be seen within three days
or so of rehydration but we recommend that the cultures be ob
tained or rehydrated in
good time to allow between five to ten days before they are needed for observation
(see SSERC Bulletin 209).


If the alternative, investigative approach is adopted the pupils are likely to suggest the
use all or any of:




Clear pla
stic rulers to measure the apparent diameters of the field(s) of view



Graph paper with mm squares



The above photocopied onto acetate (ohp transparencies)



A microscope with a digital or video camera (the Motic model has software with
a measurement facility)


Although the risks from these organisms are minimal, as standard Good Laboratory
Practice benches should be wiped over with hot water and detergent (or a surfactant
disinfectant solution) after this practical.


Practical: Looking at Fungi


Per group


Bea
ker with a little clean, fresh water


Petri dish containing glass slides and coverslips

2 x sterile loops




Microscope

Pipette

Bottle of 1% bleach

Discard jar containing 1% Virkon




To share


Streak plate of
Saccharomyces cerevisiae

(yeast)

Paper towel
s

Sterile loops (those suggested for use are the pre
-
sterilised disposable plastic types)



To prepare streak plates of Saccharomyces cerevisiae


Streak plates of yeast should be prepared according to the Microbiology Techniques
Cards. Instructions for the

sterilisation of pipettes and filter discs are described in a
separate sheet. The yeast is grown on sterile YGA (Yeast glucose Agar).


Preparation of Yeast Glucose Agar


Materials (for 1 litre of medium)


20g glucose

20g bactopeptone

10g yeast extract

0.1
M sulphuric acid

distilled water

20g agar



Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



Instructions

1.

Wear a lab coat.

2.

Weigh glucose, bactopeptone and yeast extract into a beaker.

3.

Add distilled water to 1 litre mark.

4.

Stir thoroughly and adjust to pH 6.

5.

Add agar

6.

Autoclave at 121

C for 15 minutes.

7.

Pour

plates as described in Microbiology Techniques Manual or CD
-
ROM. If the
plates are going to be used immediately, 15cm
3

agar per plate will be adequate. If
plates are to be stored before use pour them somewhat thicker


say 20cm
3
per
plate.

Although the
risks from this organisms are minimal, as standard Good Laboratory
Practice benches should be wiped over with hot water and detergent (or a surfactant
disinfectant solution) after this practical.


Demonstrations


looking at fungi


If the suggestion (Teach
er’s Guide) to set up a video microscopy demonstration is
followed then the yeast culture can be simply set up using a 2% w:v glucose solution in
which to grow the yeast cells. For longer term liquid culture then use a small volume of
yeast glucose broth (
say, 0.2g of glucose and 0.1g of yeast extract in 10 cm
3

of distilled
or deionised water.


Practical: Looking at bacteria


Per group

Prepared slides of stained bacteria




Microscope

Discard jar containing 1% Virkon


Slides of bacteria can either be bough
t or prepared and stained.


Preparing smears


Growing the bacteria and making stained smears are tasks for a technician or teacher
trained to support microbiological work at Level 3.

Bacillus subtilis
,
Micrococcus luteus

or
E coli

should be grown on nut
rient agar and
stained with a simple stain such as methylene blue. Instructions for growing bacteria,
and preparing stained slides are provided in
The Microbiology Techniques Cards

and
CD
-
Rom.

Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide





MICROORGANISMS AND FOOD HYGIENE


Practical: Where are mic
ro
-
organisms found?


Per group


2 sterile nutrient agar plates


clean cotton buds


clean fresh tap water

Bottle of disinfectant containing 1% bleach

Discard jar containing 1% Virkon


Prepare nutrient agar plates as described in Microbiology Techniques Card
s or CD
-
Rom. Plates must be held closed by sellotaping with small pieces of sellotape linking lid
to base, diametrically opposed on the plate. There should not be so much tape as to
obscure the results. Plates must not be reopened after inoculation.

On c
ompletion of
the practical, all plates should be autoclaved then placed in a black bin bag and
disposed of with normal rubbish.


Practical: Investigating the effect of cleaning on the number of microorganisms
present


Per group


Marker pen

2 sterile nutrie
nt agar plates


To share


Cotton buds

Clean, fresh water

Absorbent paper towels

Antibacterial soap

1% bleach

Dettol


working concentration (0.25% v:v)

Detergent


working concentration

Sellotape and scissors

Self
-
seal bags


Prepare nutrient agar plates as

described in Microbiology Techniques Cards or CD
-
Rom.


Plates must be held closed by sellotaping with small pieces of sellotape linking lid to
base, diametrically opposed on the plate. There should not be so much tape as to
obscure the results. Plates m
ust not be reopened.


On completion of the practical, all plates should be autoclaved placed in an opaque
bag, such as a black bin bag, then disposed of with normal rubbish.

Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



Practical: Investigating the effect of temperature on the growth and survival of
yeast cells.


Per group


Marker pen




Discard jar containing 1% Virkon

3 sterile YGA plates



Bottle of disinfectant containing 1% bleach

3 inoculation loops

Streak plate of
Saccharomyces cerevisiae



To share


Sellotape

Paper towels


For the recipe fo
r YGA plates see the previous section on ‘Looking at Fungi’

Plates streaked by the pupils should be sealed by sellotaping with small pieces of
sellotape linking lid to base, diametrically opposed on the plate. There should not be
so much tape that it obs
cure the results. On completion of the practical, all plates
should be autoclaved placed in an opaque bag, such as a black bin bag, then disposed
of with normal rubbish.


CAUSES, PREVENTION AND TREATMENT OF OTHER MICROBIAL DISEASES


Practical: Investigatin
g the effect of antifungals on the growth of yeast


Per group


Marker pen


2 streak plates of a yeast

2 x 2cm
3

sterile water




Petri dish containing 6 filter discs

2 sterile YGA plates




2 sterile pipettes and bulbs

2 pairs fine forceps




discard jar co
ntaining 1% Virkon

2 glass spreaders




covered container of ethanol (IMS)

Bunsen burner


To share


antifungal treatments


Plates streaked by the pupils should be held closed by sellotaping with small pieces of
sellotape linking lid to base, diametrically
opposed on the plate. There should not be
so much tape that it obscure the results. On completion of the practical, all plates
should be autoclaved, placed in a black plastic bin bag then disposed of with normal
rubbish
.

Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



MICROORGANISMS


BENEFICIAL AND H
ARMFUL EFFECTS WHEN THEY
GROW


Practical: Making a Compost Column


See SAPS website:


www.saps.org.uk


Practical: Investigating the growth of moulds on different types of bread


Materials


Per group


Marker pen

6 self
-
seal polythene bags

Acetate grid


To share


Organic white bread

Organic brown bread

White bread with preservative

Scissors

Labels


Sell
-
by dates

on the bread should be the same if possible.


Acetate grids can be produced by photocopying squared or graph p
aper on to acetate
sheets, then cut into bread slice sized pieces.


Bags containing the mouldy bread should not be reopened.


At the end of the practical work, the slices of mouldy bread should be autoclaved, still
in their sealed bags, then placed in an

outer black bin bag and disposed of with normal
rubbish.


Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide



Practical: Finding the best conditions to make dough rise


Per group of 2


100cm
3

measuring cylinder

250 cm
3

beaker

spatula

10 cm
3

or 20 cm
3

syringe

Stirring rod

Stopclock


To Share


Flour

Beaker

with freshly prepared yeast suspension

Beaker with warm water

Sugar

teaspoons


Tins of traditional dried yeast used (


not the fast acting type)


Yeast solution


prepare just before practical is carried out
-

each group of six students
requires 80 cm
3
.


Add 10g dried yeast to every 100 cm
3

warm water and stir for 5 minutes till
resuspended.


Economy supermarket white flour is used


Students working in pairs within groups of six.


Alternative arrangement


Where a large number of pupil pairs might be carr
ying out this activity, it can be a bit of
a
guddle

dishing out the aliquots of 10% w:v yeast solution. If time for preparation
allows, then instead weigh out 4g lots of yeast and put each of these into a bijoux
bottle. Each group of six pupils will need t
wo of these bottles with a pre
-
weighed yeast
sample. Pupils then add one of these 4g lots of yeast to 40 cm
3

of warm water in a
beaker and then proceed as per the rest of the instructions.

Improving Science Education, 5
-

14


October 2003

SAPS Biotechnology Scotland Project

Biotechnology


Trial Materials

Microbiology


Technical Guide




VISUAL AIDS AND OTHER THIRD PARTY RESOURCES


1.


Websites for images

see in particular:


The Microbial World
-

http://helios.bto.ed.ac.uk/bto/microbes/

Fun facts about fungi
-

http://www.herb.lsa.umich.e
du/kidpage/factindx.htm

Micscape (run by Microscopy UK
-

www.microscopy
-
uk.net/mag/indexmag.html


From Micscape you can also access the Virtual Pond and The Pond Life Identification
Kit, The Sm
allest Page on the Web, and link to Wim van Egmond’s delightful sites
such as the Micropolitan Museum of Microscopic Art Forms managed by the Institute
for the Promotion of the Less than One Millimeter.


See the NationalCentre for Biotechnology Education

(NCBE) website for details of
growing Oyster Mushrooms



www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/oyster.html


2.

The Field Studies Council has keys for the ident
ification of freshwater organisms
see
-

www.field
-
studies
-
council.org/


3.

SSERC and SAPS now have a stock of the Society of General Microbiology (SGM)
“World of Microbes” booklet and sets of posters. We ca
n provide them free of
charge on receipt of a self addressed C4 (approx. 32 x23 cm) envelope with a 70p
stamp. See also the SGM educational website at
www.microbiologyonline.org.uk


4.

The Code of Practice f
or Safety in Microbiology can be downloaded from the
SSERC website (Members’ section. User Name and Password required).


5.

The Code is also part of the SSERC CD ROM on Microbiological Techniques see
the SSERC website for details. (
www.ssserc.org.uk
)


6.

A SSERC 5
-
14 Microbiology CD ROM is planned which may have cached versions
of several of the above resources.


ADDRESSES


Blades Biological, Cowden, Edenbridge, Kent, TN8

7DX. T:

01342

850242, F:

01342

850924,

E:

info@blades
-
bio.co.uk

W:
www.blades
-
bio.co.uk


Scientific Laboratory Supplies Ltd., Orchard House, The Square, Hessle,

East Yorkshire, HU13 AE T: 01482 649665 F: 01482 6496
67

E:
accounts@scientic
-
labs.com


Sciento, 61 Bury Old Road, Whitefield, Manchester, M25 5TB T : 0161 773 6338


Science and Plants for Schools (SAPS), Homerton College, Cambridge, CB2 2PH T:01223
507168 W:

www.saps.plantsci.cam.ac.uk


SAPS Biotechnology Scotland Project, 2nd Floor, St Mary’s Land, 23 Holyrood Road, Edinburgh
EH8 8AE, T:

0131

558 8212 F:0131 558 8191 E:
S
APS@sserc.org.uk


(
AND AT:
Quest Biotech Laboratory, Dollar Academy, Dollar, FK14

7DU. T:

01259

743753).


ISE 5
-
14 c/o SSERC, 2
nd

Floor, St Mary’s Land, 23 Holyrood Road, Edinburgh EH8 8AE T:
0131 558 8180 F: 0131 558 8191 E:
sts@sserc.org.uk

Also at Learning and Teaching Scotland
: E:
ISETeam@LTScotland.org.uk