Haruhiko Jimbo

The repair of photosystem II (PSII) is particularly sensitive to oxidative stress and the inhibition of repair is associated with oxidative damage to the translational elongation system in the cyanobacterium <i>Synechocystis</i> sp. PCC 6803. However, the molecular mechanisms underlying this inhibition are unknown. We previously demonstrated in vitro that EF-Tu, a translation factor that delivers aminoacyl-tRNA to the ribosome, is inactivated by reactive oxygen species via oxidation of the Cys r

In photosynthetic organisms, the repair of photosystem II (PSII) is enhanced after acclimation to strong light, with the resultant mitigation of photoinhibition of PSII. We previously reported that oxidation of translation elongation factor EF-Tu, which delivers aminoacyl-tRNA to the ribosome, depresses the repair of PSII in the cyanobacterium <i>Synechocystis</i> sp. PCC 6803. In the present study, we investigated the role of EF-Tu in the repair of PSII after acclimation of <i>Synechocystis</i>

Free fatty acids (FFA) generated in cyanobacterial cells can be utilized for the biodiesel that is required for our sustainable future. The combination of FFA and strong light induces severe photoinhibition of photosystem II (PSII), which suppresses the production of FFA in cyanobacterial cells. In the present study, we examined the effects of exogenously added FFA on the photoinhibition of PSII in <i>Synechocystis</i> sp. PCC 6803. The addition of lauric acid (12:0) to cells accelerated the pho

Photosystem II (PSII) contains many lipid molecules that are essential for the function and maintenance of PSII. Under strong light conditions, PSII complexes are dynamically modified during the repair process; however, the molecular mechanism of the dynamic changes in the PSII structure is still unclear. In the present study, we investigated the role of a lipase in the repair of PSII in Synechocystis sp. PCC 6803. We identified a protein encoded by the sll1969 gene, previously named lipase A (l

Membrane lipid remodeling in plants and microalgae has a crucial role in their survival under nutrient-deficient conditions. Aquatic microalgae have low access to CO₂ , an essential carbon source for photosynthetic assimilates; however, 70-90 mol% of their membrane lipids are sugar-derived lipids (glycolipids) such as monogalactosyldiacylglycerol (MGDG). In this study, we discovered a new system of membrane lipid remodeling responding to CO₂ in Synechocystis sp. PCC 6803, a

Free fatty acids (FFAs) are generated by the reaction of lipases with membrane lipids. Generated polyunsaturated fatty acids (PUFAs) containing more than two double bonds have toxic effects in photosynthetic organisms. In the present study, we examined the effect of exogenous FFAs in the growth medium on the activity of photosystem II (PSII) under strong light in the cyanobacterium <i>Synechocystis</i> sp. PCC 6803 (<i>Synechocystis</i>). PUFAs but not monounsaturated fatty acids accelerated the

Cyanobacteria inhabit areas with a broad range of light, temperature and nutrient conditions. The robustness of cyanobacterial cells, which can survive under different conditions, may depend on the resilience of photosynthetic activity. Cyanothece sp. PCC 8801 (Cyanothece), a freshwater cyanobacterium isolated from a Taiwanese rice field, had a higher repair activity of photodamaged photosystem II (PSII) under intense light than Synechocystis sp. PCC 6803 (Synechocystis), another freshwater cyan

Photosynthetic electron transport is carried out by the electron carrier, plastoquinone (PQ). Recently, another form of PQ, acylplastoquinol (APQ), was discovered in Synechocystis sp. PCC 6803 (Synechocystis), but its physiological function in photosynthesis is unclear. In the present study, we identified a lipase encoded in sll0482 gene in Synechocystis that deacylates APQ and releases a free fatty acid and a reduced PQ (plastoquinol, PQH₂), which we named acylplastoquinol lipase (AP

A sufficient source of organic nitrogen can be a game-changer in plant ecology and for agriculture.Currently, almost 50% of the global population is dependent on the addition of nitrogen fertilizer (Stewart et al. 2005).However, the environmental pollution caused by its production and consumption prevents its sustainable use in the future.Bacterial N 2 -fixation that is catalyzed by nitrogenase (encoded by the nif gene cluster), has been hailed as the alternate 'next-generation' in N fertilizers

Photosynthetic organisms alter the lipid composition of the thylakoid membrane in response to environmental conditions. Phosphatidic acid (PA) is the branch point in the biosynthetic pathways of glycolipids and a phospholipid, phosphatidylglycerol (PG). PA and its dephosphorylated form, diacylglycerol (DG), are mutually convertible by PA phosphatase (PAP) and DG kinase (DGK). Thus, the activities of PAP and DGK appear to regulate the balance between glycolipids and PG in thylakoid lipid biosynth

Objective: Recently, chemoradiotherapy has had a tendency to be given priority compared with surgery in the treatment of external auditory canal and middle ear cancer. The objective of this paper is to confirm the effectiveness of the surgery as a salvage therapy after chemoradiotherapy.