Novel nuclear-encoded subunits of the chloroplast NAD(P)H dehydrogenase complex

The NAD(P)H dehydrogenase (NDH) complex functions in photosystem I cyclic electron transfer in higher plant chloroplasts and is crucial for plant responses to environmental stress. Chloroplast NDH complex is a close relative to cyanobacterial NDH-1L complex, and all fifteen subunits so far identified in NDH-1L have homologs in the chloroplast NDH complex. Here we report on the identification of two nuclear-encoded proteins NDH48 and NDH45 in higher plant chloroplasts and show their intimate association with the NDH complex. These two membrane proteins are shown to interact with each other and with the NDH complex enriched in stroma thylakoids. Moreover, the deficiency of either the NDH45 protein or the NDH48 protein in respective mutant plants leads to severe defects in both the accumulation and the function of the NDH complex. The NDH48 and NDH45 proteins are not components of the hydrophilic connecting domain of the NDH complex but are strongly attached to the hydrophobic membrane domain. We conclude that NDH48 and NDH45 are novel nuclear-encoded subunits of the chloroplast NDH complex and crucial both for the stable structure and function of the NDH complex.     

Actin depolymerizing factor stabilizes an existing state of F-actin and can change the tilt of F-actin subunits

Proteins in the actin depolymerizing factor (ADF)/cofilin family are essential for rapid F-actin turnover, and most depolymerize actin in a pH-dependent manner. Complexes of human and plant ADF with F-actin at different pH were examined using electron microscopy and a novel method of image analysis for helical filaments. Although ADF changes the mean twist of actin, we show that it does this by stabilizing a preexisting F-actin angular conformation. In addition, ADF induces a large ( approximately 12 degrees ) tilt of actin subunits at high pH where filaments are readily disrupted. A second ADF molecule binds to a site on the opposite side of F-actin from that of the previously described ADF binding site, and this second site is only largely occupied at high pH. All of these states display a high degree of cooperativity that appears to be an integral part of F-actin.     

Axial eye length after retinal detachment surgery

Changes in the eye axial diameter were studied to assess the eye globe impact of conventional operation for retinal detachment. The study included 69 eyes in 69 patients operated on for rhegmatogenous retinal detachment. There were 46.4% of men and 53.6% of women, mean age 52.7 (+/- 15.21) years. Results of preoperative and postoperative ultrasonographic measurement of axial diameter are presented. The mean preoperative and postoperative eye axial diameter was 23.69 (+/- 1.84) mm and 24.43 (+/- 1.91) mm, respectively. Postoperative results showed the axial eye length to increase by a mean of 0.74 (+/- 0.44) mm, yielding a statistically significant difference from the preoperative measurement (p < 0.001). The mean myopia induced by this eyeball elongation was 1.77 D. The encircling band with and without segmental buckling used in surgical repair of retinal detachment creates circular and segmental indentation of the eyeball, thus increasing its axial length. The myopia induced by elongation of the eyeball results in considerable myopia, which requires appropriate correction in the early postoperative period to achieve favorable vision rehabilitation.     

Clinical importance of the lens opacities classification system III (LOCS III) in phacoemulsification

The aim of this study was to compare the correlation of features of cataracts graded by the Lens Opacities Classification System, version III (LOCS III) with recorded operative characteristics during the phacoemulsification. The retrospective study included 245 cases operated on by a single surgeon from October 2003 to March 2004. The cataract was graded at the biomicroscope using the 4 grading scales of the lens opacities classification system, version III (LOCS III); nuclear opalescence (NO), nuclear color (CO), cortical cataract (C) and posterior subcapsular cataract (P). We recorded 2 intraoperative characteristics: machine measured phacoemulsification time, and average machine power. The machine recorded phacoemulsification time and average power correlated positively with the estimated nuclear color (NC) scale and nuclear opaclescence (NO) scale. Grading within categories of cortical cataract (C) and posterior subcapsular cataract (P) did not correlate with any of the operative variables. Exponentially, greater phacoemulsification energy was required as NC and NO increased. LOCS III grading system enables the surgeon to anticipate potential pitfalls and to adapt the operative technique to the individual patient.     

Full-thickeness anterior blepharotomy and transpalpebral fat decompression in Graves' orbitopathy

A chief morbidity of Graves eye disease is eyelid retraction and exophthalmus. Transpalpebral orbital fat removal accomplished with full thickness anterior blepharotomy was performed in 4 patients (5 orbits). Preoperative and postoperative ocular exposure symptoms, visual acuity, upper eyelid retraction and proptosis were evaluated. In all 5 operated orbits preoperative symptoms resolved; good results were achieved from the functional and cosmetic point of view. Full-thickness anterior blepharotomy combined with fat decompression is a safe and effective surgery for patients with upper eyelid retraction and exophthalmus due to enlarged orbital fat compartment.     

Refining the structure of the Halobacterium salinarum flagellar filament using the iterative helical real space reconstruction method: insights into polymorphism

The eubacterial flagellar filament is an external, self-assembling, helical polymer approximately 220 A in diameter constructed from a highly conserved monomer, flagellin, which polymerizes externally at the distal end. The archaeal filament is only approximately 100 A in diameter, assembles at the proximal end and is constructed from different, glycosylated flagellins. Although the phenomenology of swimming is similar to that of eubacteria, the symmetry of the archebacterial filament is entirely different. Here, we extend our previous study on the flagellar coiled filament structure of strain R1M1 of Halobacterium salinarum. We use strain M175 of H.salinarum, which forms poly-flagellar bundles at high yield which, under conditions of relatively low ionic-strength (0.8 M versus 5 M) and low pH ( approximately 2.5 versus approximately 6.8), form straight filaments. We demonstrated previously that a single-particle approach to helical reconstruction has many advantages over conventional Fourier-Bessel methods when dealing with variable helical symmetry and heterogeneity. We show here that when this method is applied to the ordered helical structure of the archebacterial uncoiled flagellar filament, significant extensions in resolution can be obtained readily when compared to applying traditional helical techniques. The filament population can be separated into classes of different morphologies, which may represent polymorphic states. Using cryo-negatively stained images, a resolution of approximately 10-15 A has been achieved. Single alpha-helices can be fit into the reconstruction, supporting the proposed similarity of the structure to that of type IV bacterial pili.