title: Effects of levofloxacin hydrochloride on photosystem II activity and heterogeneity of Synechocystis sp.
abstract: Effects of LH on photosynthesis of Synechocystis sp. were investigated by a variety of in vivo chlorophyll fluorescence. O2 evolution and the photosystem II (PSII) activity were clearly inhibited by LH. Exposure to LH increased the proportion of PSIIbeta and this weakened the connectivity between PSII units and hindered excitation energy-transfer between PSII units. LH decreased the density of the active photosynthetic reaction centers, inhibited electron transport, and increased the dissipated energy flux per reaction center. The inhibitory effect of LH on Q(A)(-) reoxidation process could be divided into several stages. LH first inhibited the electron transfer from Q(A)(-) to Q(B) by weakening the connectivity between Q(A)(-) and Q(B), and PQ binding began taking part in Q(A)(-) reoxidation. At the second stage, the connectivity between Q(A)(-) and PQ pool was broken and inhibition on PQ binding occurred. At this stage, some Q(A)(-) began to be oxidized by S2(Q(A)Q(B))(-). Finally, when the connectivity between Q(A)(-) and Q(B) and PQ was completely broken, all Q(A)(-) was oxidized through charge recombination.
authors: Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China.
authors: Xiangliang
authors: X
authors: Pan
authors: Daoyong
authors: D
authors: Zhang
authors: Xi
authors: X
authors: Chen
authors: Guijin
authors: G
authors: Mu
authors: Lanhai
authors: L
authors: Li
authors: Anming
authors: A
authors: Bao
mesh_terms: D000900:Anti-Bacterial Agents / Q000633:toxicity*; D002734:Chlorophyll / Q000378:metabolism; D064704:Levofloxacin; D015242:Ofloxacin / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D046939:Synechocystis / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D064704:Levofloxacin; D015242:Ofloxacin