Volume 1 Number 1
Feature articles
Marine bioluminiscence
Edith A. Widder Harbor Branch Oceanographic Institution, Fort Pierce, USA. Why do so many animals in the open ocean emit light? Bioluminescence is visible light made by living creatures. Such creatures are rare on land but extremely common in the oceans.
Read the article
movies
Yeasts
John Grainger The University of Reading, UK.
The fermentation processes of yeasts have maintained their importance from the arts and crafts of ancient times to the commercial processes of the modern food and beverage industry. In addition, as the importance of yeasts to both fundamental and applied research became increasingly appreciated in the second half of the 20th century...Read the article
TeleHeart
Michael Axelsson, Jordi Altimiras and Koullis Pitsillides Zoologiska Institutionen, Göteborgs universitet, SE.
The way we teach physiology has been and is still undergoing major changes. There is an obvious need to provide a more integrated education that gives students the capacity to confront and solve problems...Read the article
Practical protocols
- Bacterial illumination Dean Madden , NCBE, The University of Reading, UK. Britt-Marie Lidesten Erik Dahlberggymnasiet, Jönköping, SE. PDF
- DNA from 'caviar' Elisabeth Strömberg, Department of Zoology, University of Gothenburg, SE. PDF
- Modelling the helix, John Schollar, NCBE, The University of Reading, UK. PDF
- Sourdough bread, Dean Madden , NCBE, The University of Reading, UK. PDF
- The microbial fuel cell, Dean Madden och John Schollar, NCBE, The University of Reading, UK. PDF
Reviews
Genome - the autobiograpfy of a species in 23 chaptersMatt Ridley (2000) Egmond Richter AB, Malmö.
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The Sequence GenomeKevin Davies (2002) Orion, London (Updated edition)
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GATTACAAndrew Niccol, Director (1997) Columbia Tristar Home video.
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The Schollar Test
Alternative micropipettes
John Schollar tests equipment for school biology... sometimes to destruction. In this issue, John tests inexpensive alternatives to conventional micropipettes.
The products under test are:
- Poulten and Graf 'Mini pipet'
- LTI 'Graduate' pipette
- NCBE 'Microsyringe'
- Tricontinent 'Minipet'
- Eppendorf 'pen' dispenser
- Drummond 'Wiretrol II'
- Syringe with calibrated tip (DIY)
- Alpha 1 mL 'Pastette'
Most secondary schools would find the price of micropipettes for whole class use prohibitive. Typically a variable-volume device will cost GBP 125, and a fixed volume micropipette at least GBP 50.
Devices capable of measuring microlitre volumes are though, an essential requirement if one is to carry out practical molecular biology. Consequently, much ingenuity has been directed over the last 15 years into finding inexpensive alternatives for school use. Early efforts included devices such a conventional syringe with a wire placed down the needle (1). This was in effect a home-made version of the displacement capillary pipettes that preceeded the micropipette. Others used existing materials in a new way by, for example, fitting a calibrated micropipette tip onto a syringe (2), or by using disposable inoculation loops that held known volumes of liquid (3).
Approaches such as these are still useful and depending upon the circumstances, can be highly efective. Increasingly, however, commercial manufacturers have started to produce inexpensive pipetting devices. Some are intended as single- or limited-use items for diagnostic kits and have found their way into schools; others have been developed specifically for the education market.
There is a tendancy to regard these devices as second-best; the school teachers' poor alternative to 'real' equipment. This is a narrow perspective however (unless one is merely in the business of training people how to use apparatus). In the school laboratory, accuracy may be less important than durability and ease-of-use. Many a science centre has seen costly micropipettes reduced to broken plastic after a few months, or realised that the disappointing results with expensive reagents are caused by pipettes that are too difficult and unfamiliar for most visitors to handle. The motivation that students gain by handling 'the real thing' can quickly evaporate when the results don't match up.
Selecting a microlitre measuring device for school use is therefore not a straightforward task. Accuracy, durability, ease-of-use and the cost of consumable items (such as tips) must all be considered carefully.
This survey of 8 devices covers a broad range from the home-made to the repurposed and the purpose-built.
References
1. Schollar, J. (1990) Pump up the volume NCBE Newsletter (10) 14.
2. Miller, M.B. (1993) DNA technology in schools. A straightforward approach. BIO/technology Education 4 (1) 15-22.
3. See, for example, bacterial transformation kits, such as Bio-Rad's 'Explorer' series that use disposable inoculation loops for dispensing plasmid DNA.
Image lab
The Twiglet genome
John says:
"I first started collecting Twiglets like this over four years ago. About one packet in every 20 has a pair of fused Twiglets that look just like a metaphase chromosome. You have to eat a lot of Twiglets to collect the entire genome.
The most difficult part was finding the range of sizes. But I can assure you that there has been no foul play here - these Twiglets are exactly as I found them - I wasn't tempted to nibble the ends off them, you know. The best thing of course was beating The Wellcome Trust to the genome, not to mention Celera Genomics. And my Genome Project cost a fraction of the vast sums they spent on theirs." John Schollar, NCBE
Editor's note: Twiglets are small savoury biscuits, usually flavoured with yeast extract, that can be bought in the UK.