Studies On Differential Proteomics Of Nostoc Flagelliforme Subjected To UU-B Radition

Nostoc flagelliforme, a kind of terrestrial cyanobacterium, is fairly adaptable to UV-B radiation. In this research, N. flagelliforme were exposed to enhanced UV-B radiation. Its ultrastructure was observed with Transmission electron microscope. The physiological indictors including protective enzyme activity and photosynthetic pigments were measured by the application of plant physiology theories and methods. The different proteins were identified and its possible biological functions were explained by differential proteomics methods and techniques. The exploration provided basis for researching mechanism of N. flagelliforme resistance to UV-B radiation.1With the enhancement of UV-B radiation, the glial sheathe silhouette became irregular. The structure particles and glycogen granules disappeared gradually. The arrangement and distribution of thylakoid membrane tended to be irregular.2With the enhancement of UV-B radiation, The content of the following indicators decreased, such as soluble protein, phycobilin, Chlorophyll a and Carotenoids. MDA content increased at the beginning and then decreased. The content of Superoxide anion radicals tended to increase. The content of Proline and soluble sugar increased and then tended to decrease. The activity of CAT increased.The activity of SOD increased at the beginning and then decreased. The content of MAAs increased at the beginning and then decreased.3The proteins of N. flagelliforme, exposed under the UV-B radiation in different degree, were separated by IEF-SDS-PAGE with the IPG Gradient within the range of pH4～7. The2-DE graphs were analyzed by Image Master2D software. The results showed that1055protein spots were detected when N. flagelliforme were exposed to fluorescent for144h,1086protein spots were detected when it was exposed to UV-B radiation for24h,1009proteins spots were detected when it was exposed to UV-B radiation for72h,970protein spots were detected when it was exposed to UV-B radiation for144h. Through the analyzing, there were75protein spots whose change of expressed abundance was more than2-fold. Among these protein spots,24were up-regulated,33were down-regulated and9were undulatory-regulated.4. By MALDI-TOF-TOF/MS analysis and protein database searching,66differential protein spots were identified. They were, carbohydrate-selective porin OprB (Spot.12)、NmrA family protein (Spot.34)、COG2335:Secreted and surface protein containing asciclin-like repeats (Spot.55)、30S ribosomal protein S2(Spot.58)、nucleotide-binding protein (Spot.69)、zinc-containing alcohol dehydrogenase superfamily protein (Spot.2)、thioredoxin (Spot.4)、oxidoreductase (Spot.11)、Peroxiredoxin (Spot.25、67、cysteine desulfurase activator complex subunit SufB (Spot.27)、fructose-1,6-bisphosphate aldolase (Spot.8、9、NAD(P)H dehydrogenase (quinone)(Spot.17)、ATPase (Spot.22、33)、 Phosphoribulokinase(Spot.23)、C-phycocyanin beta subunit(Spot.26)、Fructose/tagatose bisphosphate aldolase (Spot.30)、Ribulose1,5-bisphosphate carboxylase, large subunit (Spot.36)、alpha-glucan phosphorylase (Spot.42)、ribose5-phosphate isomerase (Spot.47)、threonine synthase (Spot.20)、 glutamine synthetase (Spot.32)、heat shock protein GrpE (Spot.56). There are also4unknown differential proteins which mainly involved in structural protein synthesis, anti-oxidative metabolism, nitrogen metabolism, glucose metabolism and other physiological functions. The results had built the base for further research on molecular mechanism in UV-B-resistant of N. flagelliforme.