Chlorophylls d and f and Their Role in Primary Photosynthetic Processes of Cyanobacteria.

The finding of unique Chl d- and Chl f-containing cyanobacteria in the last decade was a discovery in the area of biology of oxygenic photosynthetic organisms. Chl b, Chl c, and Chl f are considered to be accessory pigments found in antennae systems of photosynthetic organisms. They absorb energy and transfer it to the photosynthetic reaction center (RC), but do not participate in electron transport by the photosynthetic electron transport chain. However, Chl d as well as Chl a can operate not only in the light-harvesting complex, but also in the photosynthetic RC. The long-wavelength (Qy) Chl d and Chl f absorption band is shifted to longer wavelength (to 750 nm) compared to Chl a, which suggests the possibility for oxygenic photosynthesis in this spectral range. Such expansion of the photosynthetically active light range is important for the survival of cyanobacteria when the intensity of light not exceeding 700 nm is attenuated due to absorption by Chl a and other pigments. At the same time, energy storage efficiency in photosystem 2 for cyanobacteria containing Chl d and Chl f is not lower than that of cyanobacteria containing Chl a. Despite great interest in these unique chlorophylls, many questions related to functioning of such pigments in primary photosynthetic processes are still not elucidated. This review describes the latest advances in the field of Chl d and Chl f research and their role in primary photosynthetic processes of cyanobacteria.

Photobiological hydrogen production and artificial photosynthesis for clean energy: from bio to nanotechnologies.

Global energy demand is increasing rapidly and due to intensive consumption of different forms of fuels, there are increasing concerns over the reduction in readily available conventional energy resources. Because of the deleterious atmospheric effects of fossil fuels and the uncertainties of future energy supplies, there is a surge of interest to find environmentally friendly alternative energy sources. Hydrogen (H2) has attracted worldwide attention as a secondary energy carrier, since it is the lightest carbon-neutral fuel rich in energy per unit mass and easy to store. Several methods and technologies have been developed for H2 production, but none of them are able to replace the traditional combustion fuel used in automobiles so far. Extensively modified and renovated methods and technologies are required to introduce H2 as an alternative efficient, clean, and cost-effective future fuel. Among several emerging renewable energy technologies, photobiological H2 production by oxygenic photosynthetic microbes such as green algae and cyanobacteria or by artificial photosynthesis has attracted significant interest. In this short review, we summarize the recent progress and challenges in H2-based energy production by means of biological and artificial photosynthesis routes.

Nano-sized manganese-calcium cluster in photosystem II.

Cyanobacteria, algae, and plants are the manufacturers that release O2 via water oxidation during photosynthesis. Since fossil resources are running out, researchers are now actively trying to use the natural catalytic center of water oxidation found in the photosystem II (PS II) reaction center of oxygenic photosynthetic organisms to synthesize a biomimetic supercatalyst for water oxidation. Success in this area of research will transcend the current bottleneck for the development of energy-conversion schemes based on sunlight. In this review, we go over the structure and function of the water-oxidizing complex (WOC) found in Nature by focusing on the recent advances made by the international research community dedicated to achieve the goal of artificial water splitting based on the WOC of PS II.

Nearest neighbor analysis of D1 and D2 subunits in the photosystem II reaction center using a bifunctional cross-linker, hexamethylene diisocyanate.

A cross-linked product between the D1 and D2 subunits was generated by treating isolated spinach PS II reaction center with a bifunctional cross-linker, 1,6-hexamethylene diisocyanate. To obtain information on the contact site(s) between D1 and D2 proteins, the cross-linked product was cleaved by CNBr, the resultant fragments were separated using a reverse-phase HPLC, and then the partial sequence of the cross-linked polypeptide fragments were determined. By comparing the results with the deduced amino acid sequence of the D1 and D2 proteins from spinach, it is concluded that the C-terminal domains of the D1 subunit (D308-A334) and that of the D2 subunit (Y297-L353) are in close proximity.

Orientation and nearest neighbor analysis of psbI gene product in the photosystem II reaction center complex using bifunctional cross-linkers.

Two distinct cross-linked products containing psbI gene product were generated in the photosystem II reaction center complex from spinach by treatment with bifunctional reagents directed to amino groups. The first product, which was generated by a 3,3'-dithiobis(succinimidyl propionate) treatment, is deduced to be formed between the epsilon-amino group of Lys3 of the psbI gene product, and a side-chain amino group present on the stromal extension of the D2 protein. The CNBr cleavage analysis of the cross-linked product predicted that the amino group of the D2 protein engaged in the cross-linking is either one of the three lysine residues on the N-terminal fragment (from N-terminus to Met19) or the Lys268 on the 6th fragment (from Val248 to Met275). The second product, which was also generated on the stromal side by a 1,6-hexamethylene diisocyanate treatment preferentially in alkaline conditions, is predicted to be formed between the epsilon-amino group of Lys3 of the psbI gene product and the N-terminal alpha-amino group of the alpha-subunit of cytochrome b559.

15-cis-beta-carotene found in the reaction center of spinach photosystem II.

Solvent extraction at approximately 4 degrees C in complete darkness, and subsequent analysis by high-pressure liquid chromatography (at approximately 4 degrees C) using an apparatus equipped with a two-dimensional diode-array detector, spectroscopically identified 15-cis-beta-carotene in the reaction center (RC) of spinach photosystem II (PS II). The result revises a previous conclusion that beta-carotene bound to the PS II RC takes the all-trans configuration [Fujiwara, H., Hayashi, H., Tasumi, M., Kanaji, M., Koyama, Y. and Satoh, K. (1987) Chem. Lett. 2005-2008], and generalizes the concept established for purple photosynthetic bacteria that 15-cis-carotenoid is naturally selected by the photosynthetic reaction centers.

Significance of urinary fibrin/fibrinogen degradation products (FDP) D-dimer measured by a highly sensitive ELISA method with a new monoclonal antibody (D-D E72) in various renal diseases.

To diagnose the abnormalities of coagulation-fibrinolysis in various renal diseases, we developed a new monoclonal antibody (D-D E72) against fibrin/fibrinogen degradation products D-dimer (FDP D-dimer) and established a highly sensitive enzyme-linked immunosorbent assay (ELISA) for its measurement. FDP D-dimer was assessed in 102 patients with various renal diseases, and the following results were obtained: 1. The mean level of urinary FPD D-dimer in 32 normal controls was 0.69 +/- 0.60 ng/ml (mean +/- SD). 2. The level of urinary FDP D-dimer was significantly higher in primary nephrotic syndrome group (NS), chronic renal failure group (CRF) and in the group of diabetic nephropathy (DM) than in the control group. However, no difference was observed in the level of urinary FDP D-dimer between non-nephrotic chronic glomerulonephritis group (CGN) and control group. 3. No significant correlation was revealed between D-dimer and urinary protein in CGN and NS groups. These results suggest that in addition to plasma filtration the urinary FDP D-dimer in NS, CRF and DM may be also related to abnormalities of secondary fibrinolysis in intra-glomerular fibrin deposits.

Evaluation of several saccharides as osmotic agent for peritoneal dialysate.

OBJECTIVE: The carbonyl group of glucose reacts non-enzymatically with the amino group of protein to form advanced glycosylation end-products (AGEs). AGEs are found in the peritoneum of continuous ambulatory peritoneal dialysis patients, and this AGE formation is suspected to be one of the causes of impaired peritoneal function. In order to control AGE formation in the peritoneum, AGE formation and ultrafiltration in rats were examined with peritoneal dialysates using as osmotic agents saccharides that lack a carbonyl group, the saccharic acid lactobionate [molecular weight (MW) 358.30], the sugar alcohol maltitol (MW 344.32), and the nonreducing sugar nistose (MW 666.58). DESIGN: Bovine serum albumin (BSA) (25 mg/mL) was incubated with 18, 36, and 72 mg/mL maltitol, lactobionate, nistose, and glucose at 37 degrees C. After 3 or 6 weeks, amounts of furosine and N-(carboxymethyl) lysine were measured. A 20-mL intraperitoneal injection of a lactate-based dialysate (osmotic pressure 388 mOsm/kg) containing 4.34% maltitol, 4.52% lactobionate, or 8.4% nistose was given to Sprague-Dawley rats and, after 2, 4, or 6 hours, the quantity of effluent and levels of urea nitrogen and creatinine in the effluent and in serum were measured. RESULTS: No increases in furosine or N-(carboxymethyl) lysine were seen with maltitol, lactobionate, or nistose after 3 and 6 weeks of incubation with BSA; AGE formation was not observed. In the study in rats, the quantity of abdominal fluid after a 6-hour dwell was nistose > lactobionate > maltitol > glucose. No differences in dialysate-to-plasma ratios for urea nitrogen or creatinine were seen in any group. CONCLUSIONS: AGE formation in peritoneal tissue might be controlled by using saccharides with a modified carbonyl group as osmotic agents for peritoneal dialysates. Nistose is considered to yield the most efficient dialysis.

[Studies on molecular markers for hemostasis and thrombosis in various renal diseases].

In order to clarify the abnormalities of blood coagulation and fibrinolysis in patients with various renal diseases, some molecular markers for hemostasis and thrombosis were examined in comparison with those of the patients with disseminated intravascular coagulation. The results were as follows: 1) PIC was significantly higher in the patients with CGN, NS, SLE, HD and DIC than normal subjects. 2) TAT was significantly higher in the patients with CGN, NS, HD and DIC. 3) SFMC was significantly higher only in the patients of DIC. 4) FDP and FDP-E were significantly higher in the patients with HD and DIC. 5) D-dimer was significantly higher in the patients with CGN, CRF, HD and DIC. These results suggested that the abnormalities of blood coagulation and fibrinolysis in patients with various renal diseases are relatively mild, and situated between the normal subjects and patients with DIC.

A case report of allergic granulomatosis and angiitis (Churg-Strauss syndrome) with a review of the literature.

We report the case of a 67-year-old man with allergic granulomatosis and angiitis (AGA; Churg-Strauss syndrome) who developed nephrotic syndrome during his clinical course and demonstrated membranous nephropathy on renal necropsy by electron microscopy. Following the development of symptoms of bronchial asthma accompanied by eosinophilia and mononeuritis multiplex, transbronchial lung biopsy confirmed a diagnosis of AGA. The patient died of pneumonia and disseminated intravascular coagulopathy, but necropsy revealed severe tubulo-interstitial damage with neutrophilic infiltration and, in half of the glomeruli, mesangial proliferation with subepithelial dense deposits. This paper thus describes a rare case of AGA complicated by a secondary type of stage I membranous nephropathy.

[Significance of urinary fibrin/fibrinogen degradation products (FDP) measured by highly sensitive ELISA method in various renal diseases].

In order to clarify the abnormalities of intra-glomerular coagulation and fibrinolysis in patients with various renal diseases, urinary fibrin/fibrinogen degradation products (FDP) have been examined by several methods. We established a highly sensitive new method of enzyme-linked immunosorbent assay for urinary FDP. The results were as follow: 1) The mean +/- SD of urinary FDP in normal subjects was 10.30 +/- 9.08ng/ml. 2) The urinary FDP levels in chronic glomerulonephritis, nephrotic syndrome and chronic renal failure patients were significantly higher than normal subjects, and the levels in SLE, Alport's syndrome patients were higher than normal subjects. 3) The urinary FDP levels were a little bit higher in the patients with proliferative glomerulonephritis than in chronic glomerulonephritis patients with minor lesion or membranous nephropathy. 4) There was significant correlation between urinary FDP and urinary protein in chronic glomerulonephritis, while there was no correlation in nephrotic syndrome. 5) There was no correlation between urinary FDP and intra-glomerular fibrin deposits examined by immunofluorescent study in chronic glomerulonephritis, while in nephrotic syndrome, there were high levels of urinary FDP in the positive fibrin deposits cases. These results suggested that the most of the part of excretion of the urinary FDP in chronic glomerulonephritis is associated with the filtration of blood FDP to urine through the glomerular basement membrane, while in the nephrotic syndrome cases the origin of urinary FDP is related to the filtration and/or the intra-glomerular coagulation abnormalities.