OSMOSIS 14, AUTUMN 1998

Contents

Director's Letter
Workshop Calendar
Postbag
Internet questionnaire
Biotechnology news
Ideas for investigations with mosses
A propagator for small plants and seedlings

Letter from the Director

Dear Colleague,

We are always pleased when other people include SAPS materials in their inset courses. To encourage more of this we organised a 4 day meeting at the University of Warwick in June in which a total of 38 people were trained to run a variety of SAPS workshops. If you would like one of our workshops in your locality please get in touch with us at Cambridge. It is likely that we have a well trained person nearby who, with support from SAPS, can meet your needs.

I am delighted to report that, with support from Unilever, the Scottish Office and the University of Edinburgh, we shall be re-establishing SAPS Scotland at a new base in the University. Rodger McAndrew of Queensferry High School who completed an eighteen-month secondment to SAPS in June 1997, has been seconded for a further two years from September 1998. He will join forces with Marjorie Smith whose highly successful Scottish Biotechnology Project came to an end this summer. I am confident that, between them, they will develop a range of exciting resources in plant science and biotechnology and share them with teachers through high quality staff development courses. The project has valuable additional support from the Scottish Consultative Council on the Curriculum (SCCC), the Scottish Schools Equipment Research Centre (SSERC), the Higher Still Development team and local industry in Scotland.

Here in Cambridge, Mary MacDonald is now working part-time for SAPS and part-time for Nickersons BIOCEM Ltd on the Cambridge Science Park. Her work with SAPS involves care and development of the SAPS web site and the development of some exciting Enzyme Linked Immunosorbent Assay (ELISA) techniques for schools (see page 3).

Lastly Roger Delpech, Head of Biology at Haberdashers' School, will be carrying out some molecular biology development work for SAPS and more news of this will appear in future editions of Osmosis and on our web site.

Richard Price
Programme Director

Return to Top of Page

Q. I am getting very heavy growth of algae on the top of the growing medium in my 4-pots and my plants are looking unhealthy.

A. We received this enquiry from Maria Bowen at Plantasia in Swansea. At our suggestion she checked the temperature and noticed that it was at 26-27òC. We recommended that she reduce the temperature to about 22òC. When she did this the algal problem disappeared and her plants became much more healthy.

Q. My budget for science is never large enough. Are there cheaper alternatives to the growing equipment which is listed in the catalogues?

A. Fast plants and many other plants will grow very well in black film cans (see back page of Osmosis No. 11, Autumn 1996). Just make a hole in the bottom of the film can for the wick. Secondly, many hardware stores sell wooden kebab skewers which can be used as plant stakes (£1.45 for 100 from John Lewis stores - much cheaper than those from the catalogues). Many supermarkets sell strong absorbent cloths which work well as capillary matting. However, you may need to rinse this thoroughly to remove any biocides with which the clothes may have been impregnated. NB: please note J-cloth type material is not suitable for wicks because it can disintegrate after a few days.

Linda Macdonald of New Zealand writes:

Several years ago I had the opportunity to travel in the UK and USA as part of a study trip, and first encountered SAPS and Osmosis at the Lancaster ASE Conference. I was immediately struck with the practical nature of material in Osmosis, especially the student sheets dealing with growing plants in film canisters, and the excellent directions for building light-banks.

Our school was fortunate enough to win an award in Junior science which enabled us to build a light-bank trolley (it cost approximately $700 NZ) that we have used with both junior and senior students. The ideas I found in Osmosis have been integrated in our new junior unit 'Seed to Leaf', which has been a great success with our students. Fortuitously our film-canister radish growing project coincided with the volcanic eruptions of Mt. Ruapehu and we explored many permutations of the effect of ash on plant growth - radishes do not grow well in pure ash!

Many thanks to the Science and Plants for Schools team - you have helped revitalize our junior science.

Food for plants?

Q. "I can buy 'Plant food' in the shops, but my pupils were marked wrong in the SATs when they said that plants obtain their food from the soil. Why was that wrong?"

A. "Food is used by organisms for two main purposes: as a source of building materials to enable growth (or renew worn-out parts) and for energy. Plants make their own food, using energy from sunlight to combine the elements in water and carbon dioxide. Animals, however, can not make their own food; they cannot trap sunlight. Instead, they rely on plants for food, either directly or indirectly.

Plants first make carbohydrates in the process called photosynthesis (photo = light; synthesis = putting together). The carbohydrates are then converted into other foods such as fats and proteins. Small quantities of minerals are often required to make these new substances. Plants obtain these minerals from the soil but this may be deficient in what the plants need. Hence the so-called 'plant food' such as 'Baby Bio' or 'Miracle-Gro' that is watered onto the soil. Because of the confusion it can cause, it is obviously better not to refer to these solutions of minerals as 'plant food' in your teaching."

Reprinted, with permission, from Primary Science and Technology, No 9, Autumn 1997, published by CLEAPSS School Science Service.

Return to Top of Page

Plant DNA kit

Important information.

There is some confusion about two matters relating to the use of the Plant DNA protocols: firstly, the recipe for the TBE (electrophoresis) buffer and secondly, the concentration of agarose for the gels.

TBE (Tris/Borate/EDTA buffer). This is used for making up agarose gels and as the electrophoresis buffer. If you are getting erosion of the crocodile clips and/or electrodes it is likely that you are not using the correct recipe for the TBE buffer. This should be made up as follows:

10x TBE concentrate - Makes 1 litre. May be stored indefinitely at room temperature.

Ingredients:

Please note that some versions of the recipe for this buffer which was published by SAPS omit to include Sodium hydroxide, giving an incorrect pH and leading to corrosion. Secondly, the correct recipe uses Tris base and not Tris-HCl.

Those who do not wish to make up their own TBE buffer can buy the concentrated buffer ready-made up from NCBE. All you need to do then is to dilute it for use (mixing the agarose for gels and electrophoresis buffer).

For best results use 0.8% agarose for the gels and not 1% agarose as stated in the original SAPS protocols.

Return to Top of Page

INTERNET QUESTIONNAIRE

Thank you to the 215 schools who returned our Internet questionnaire, and our apologies to those who tried to e-mail us. Our correct e-mail address is:

Three quarters of the schools which replied have Internet access, and of those without, half are likely to get it in the next 12 months. The level of access varies between schools, from networked classrooms to a single machine, located in the staffroom or library. About one quarter of the respondents had Internet access at home, and this figure was similar, whether or not they had access at school. Many teachers are interested in receiving training, with sufficient interest to run one or more courses at Warwick and Cambridge and also at Edinburgh and London. Other popular locations would be Glasgow, South West England and Leeds/Manchester.

We intend to identify suitable centres for such courses and local people who would be interested in running the training sessions. Six teachers offered to help, either running courses or with possible locations. Keep an eye on the workshop calendar for more news of these.

IMMUNOASSAY TECHNIQUES - ELISA

If you are currently teaching ELISA in the school curriculum and would like to trial our new practical ELISA kit, and provide us with feedback, please contact Mary MacDonald at the SAPS Cambridge office, giving a contact name, address, school details and phone number, or email to: hom-saps@lists.cam.ac.uk

BIOTECHNOLOGY NEWS

Return to Top of Page

Thin ended wedge yields finer results

Designing equipment for educational use sometimes requires an element of compromise. This is true of the original NCBE lambda DNA electrophoresis kit, which used a four-toothed comb to create wells in the agarose gel. These teeth produce wells with a fairly large capacity that are easy to load, especially for inexperienced students. Norman Brown and his colleagues at the RNIB New College in Worcester even adapted the equipment for use by blind and partially-sighted students. Unfortunately such big wells, while simple to fill, are not ideal for all samples because they tend to produce wide and relatively indistinct bands on the gel.

Now John Schollar of the NCBE has designed a unique new comb that combines easy-of-loading with the ability to produce sharp, distinct bands. It gives wells with wide openings which taper towards the end, so that the DNA sample is concentrated at the bottom of the well. "Sharper, darker bands are easier to distinguish" John said, adding that "...the new comb also doubles as a lid over the gel tank, reducing evaporation during long runs". While more expensive (£10 for 5) than the four-tooth variety, the new comb should be more economical to use, since it produces six wells on the gel.

The six-tooth comb is now included in the Plant DNA Investigation kit supplied by the NCBE and both the students' and the technical guides in the kit have been revised to incorporate this improvement.

Both six-tooth combs and class sets of the new students' booklets are available from the National Centre for Biotechnology Education,Science and Technology Centre, Earley Gate, The University of Reading, Whiteknights, READING, RG6 6BZ tel: 0118 987 3743.

NEW Low cost microcentrifuge

Scientific discoveries, especially in the latter part of this century, have relied upon the simultaneous development of specialist equipment. Most of the modern apparatus used by scientists is beyond the budget of schools, and so whole areas of investigation are closed to them.

In molecular biology and biotechnology, a microcentrifuge is one such item of equipment. Now, Prof. John Cave of the Technology Enhancement Programme (TEP) at Middlesex University, with help from SAPS and the NCBE, has developed a low-cost microcentrifuge for schools. This will open up a new range of exciting practical work, particularly with DNA.

The centrifuge is simple, robust and has been thoroughly tested to ensure that it is safe. It can be powered by batteries or an inexpensive 12V mains adaptor (available separately from high street stores). With batteries, it has a single speed of 6,670 rpm (2,236 g), but with a suitable mains adaptor a range of speeds up to 13,000 rpm (8,494 g) is possible.

There is more information in Osmosis 15 and use this link to find out more about the centrifuge on NCBE's site.

Return to Top of Page

Ideas for investigations with mosses

All plants need water, but some plants can survive without water for long periods. For example, a small cushion of the common wall moss, Grimmia pulvinata, was stored in a desiccator for 52 weeks at 20C. When water was re-added the moss immediately resumed normal growth (1).

Mosses like G. pulvinata commonly grow in very dry places, e.g. on roofs and walls, where there is no soil. Where do they get water from and how do they absorb it? Most land plants have roots which perform several functions. The roots hold the plant in place and they also absorb water and mineral nutrients.