Griffiths, A. J.F.

Sivak, B.

Fungal Genetics Reports

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A. J.F. Griffiths

B. Sivak

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UV transmission through various clear films in mutation experiments

Kansas State University

Fungal Genetics Reports Volume 20 Article 33 UV transmission through various clear films in mutation experiments A. J.F. Griffiths University of British Columbia B. Sivak University of British Columbia Follow this and additional works at: https://newprairiepress.org/fgr This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. Recommended Citation Griffiths, A. J., and B. Sivak (1973) "UV transmission through various clear films in mutation experiments," Fungal Genetics Reports: Vol. 20, Article 33. https://doi.org/10.4148/1941-4765.1841 This Technical Note is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Fungal Genetics Reports by an authorized administrator of New Prairie Press. For more information, please contact cads@k-state.edu. UV transmission through various clear films in mutation experiments Abstract Clear films for UV mutation experiments This technical note is available in Fungal Genetics Reports: https://newprairiepress.org/fgr/vol20/iss1/33 merits of one sample. Grecrter reproducibility could probably  be achieved by the use of a microbalance. Serious deviations fromlogarithmic growth rates  occurred if the mycelia  clumped rclther  than remaining dispersed. Dry weights in the former case  were asr&h  a ZO-40%  lower than  in the latter. The clumping pottern  of growth was avoided by the removal of mycelial  fragments fromthe conidial inoculum  and by coating the inner surface of the culture flak  with dimethyl-di-chlorosilone.This work was supported by NIH grant GM 15751.- - - Loboratories  of Molecular Biology and Genetics, University of Wisconsin, Madison, Wisconsin 53706.Creighton,M.  0. and J. R. Trevithick. To overcome the necessity of constant passage  in either liquid or solid medium of theMethod for freezing slime.shin FGSC”326  (fz;  sg; a-1,  arg-I, cr-I, au), a  slime variant of N. crrzso,  freezingwas studied as a hoTdiG  method.- - - -Eight-day cultures, grown  on  Vogel’:  agar medium (I .5%  agar)  with arginine (50 mg/lM) m medium ) was washed  down with aIstream of Vogel’s orginine  SSP  medium (Vogel’s arginine medium plus 2% sucrose, 10% sorbore,  Penicillin G Sodium lOOU/ml  ofmedium, dihydrostreptomycin  rulphate  lC@g/ml  of medium) with a sterile Pasteur pipette. The milky liquid was transferred to  0sterile  tube and  centrifuged I5 minutes at 2500 rpm.The supernatont  was discorded and the residue resuspended in the freezing fluid (Vogel’s arginine SSP plus dimethyl  sulfoxide,4:)  ), until a four-fold dilution of this suspension gave on absorbance reading  of I  .O  at 280 nm on D Beckman spectrophotometer.2 ml of the concentrated suspension was placed In sterile vials, sealed and quick-frozen, using liquid nitrogen. The viols werestored a+ -7O’C  until used. To date they have been held up to three months, but longer periods of holding time ore being tested.Thwring was done in warm water  and the contents of the vial were emptied into D liter of Vogel’s medium plus arginine and anti-biotics (Penicillin and Streptomycin in the concentrations noted above). No retardation of growth has been noted when the fro-zen and thawed cultures hove been compared to others maintained  by continual passage.- - - Deportment of Biochemistry, Health Sciences, University of Western Ontario, London, Ontario, Canada.Griffiths,A.  J. F. and 8. Sivak. UVtronsmissionthrough voriws clear films in mutation experiments.To reduce the risk of contominotion  in long, or student-operated UVexposures, it is desirable to use some form of cover on  the irradiatedromple.  Traditionally quartz has been used for this purpose. Thisreport indicates that some cheaper materials are iust  0s good. Thematerials tested were: plastic Petri plates (from a/s Nokre  plost,DK 4690,  Naslev,  Denmark ); “Saran  Wrap” (from Dow Chemicals,Ltd.,122  Arrow  Road, Weston,  Ontario); “Look  Roasting Film”(from Look Film Associates, Scarborough, Ontorio  ); and “8aggier”(from Colgate-Palmolive Co.,  Ltd., New York, N. Y. ).Strip of the clear  materials from various sources were fitfed  into.*the sample cwette  of o Unicorn SP-BOO UV spectrophotometer, so)~ ; that the beam passed at right angles through one thickness. The$ behavior of the various films is shown in the Figure, in which thej base  line follows the 100%  trrmsmittonce  line. Most of the commonly-- used UV tubes (e.g., Hanovia  BBA-45, Osram HNS 12) emit ot 254millimicrons. It-&n  be seen that of those materials tested, Baggierprovide the only material which will transmit most radiation of thiswavelength’.- - - Botany Department, University of British Columbia, Vancouver8, B.C., Canada.Newcombe,K.  D. and A. J. F. Griffiths.  Adiustable This technique basically follows that  of Perkins (Neurcspora  Newrl.platforms for collecting shot asci. 9: 11  ) with the following modifications: (I)  Crosses ore  made on  filterpaper stripr  in tubes containing liquid Westergoord  medium. The med-ium contains 0.2% sucrose,  compared to the usual  2%. This drasticallyreduces conidiotian,  while maintoiling high fertility, and therefore makes the use of fluffy unnecessary. Crosses ore initiated bythe simultaneous  introduction of each parent as D drop or two of conidial suspension. (This technique was introduced to  A. J. F. G.by F. J. de Serres).  (2) Low conidiation  and the use of filter paper permit the removal from the cross tube of all  the perithecio.The paper can be cut up and placed on slides which ore held inverted on  odjurtoble  platforms over the ogor collection slcbs.  Twomodels of platform hove been used. (See figures on following page ).MDdel I has  been used extensively for the routine collection of hundreds of asci. It consists of hvo tubing clomps (a), mountedon-c  stand 6) with rapid-hardening epoxy glue. The inverted slide bearing the perithecia is placed ocrws  the top, andthe slide bearing the agar collection block is placed across the two adjustable arms and racked up into close proximity to the de-hiscing  perithecia. Two such  devices may be mounted back-to-back on  each stand.Model II is a more recent design and permits adjustment in hvo dimensions by the use of sliding plastic shelves (c). The shelves

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UV transmission through various clear films in mutation experiments

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