INVESTIGADORES
FERREYRA Gustavo Adolfo
artículos
Título:
Effect of solar radiation and the subsequent dark periods on two newly isolated and characterized Antarctic marine bacteria
Autor/es:
HERNÁNDEZ, E.. G.A. FERREYRA, W.P. MAC CORMACK
Revista:
Polar Research
Referencias:
Año: 2004 vol. 23 p. 67 - 77
Resumen:
'lwo strainso fpsychrotoleranAt ntarcticm arineb acteriaw erci solatedand
characlerizcuds ingb iochemicaal ndm oleculartc chniquesS. equencinogt
163 rRNA gene showed that UVvi strafu belongs to Ihe genrs Arthrobacter
whereas UVps strain is relatedtothe Flexibacter q)bPhag.! Bactercides
(FCB)g roup.R esponseofthest rainst o solarr adiationw ass tudiedd uring
the summcr of 1999 in Potter Cove, near Jubany station (South Shetland
Island,A ntarctica).T he effect of photosyntheticallayv ailabler adiation
(PAR,400 - 700 nn). ultraviolelA (UV-A, 320 400 nm) and ultravioletB
radiation (UV-8, 280-320 nm) on ccll viability was studied using mixed
culluresinq uartzb ottlesc overcdw ilh interferentiafli ltersa ndexposedto
solarr adiation.I n all experimentsf,o ur treatmentsw ereu sed:d ark (with
light screenedo ut),P AR (with UV tadiations creenedo ut),P AR+UV-A
(UV B screenedo ut) and PAR+UV A+UV-B. Undert he assayedc ordirions.
PAR+UV-A and PAR+UV-A+UV-B radiation showed similar
negative effects on the viabilily of the studied strains. However at the
end ofthe exposureti me, mortality valuesi n PAR+UV-A+UV-B trea!
ments were higher than those observed under PAR+UV-A lrcatments.
ln both PAR+UV-A and PAR+UV-A+UV-B treatmentsw c observed
high levels of hydrogcn peroxide compared with the da* control. The
A hrcbacter UVvr sl|rain showed significant recovery in dark condilions
after exposureto the PAR+ UV-A but not after the PAR+UV A +UV B
treatmentT. his straiflo rovedt o be more resistant o UV radiationt han
the FCB group-rclatcdU Vps strain.T he resultss howedt hal UV radiation
has a deleteriouse ffecto n theseA ntarcticm arineb acteriaa nd also
revealcdt hat the analysedc omponentos f the Antarcticb acterioplankton
may havcd ifferentr esponsews hent hey are erposedt o the samei rradiance
conditions.