The ndh genes encoding for the subunits of NAD(P)H dehydrogenase complex represent the largest family of plastid genes without a clearly defined function. Tobacco (Nicotiana tabacum) plastid transformants were produced in which the ndhB gene was inactivated by replacing it with a mutant version possessing translational stops in the coding region. Western-blot analysis indicated that no functional NAD(P)H dehydrogenase complex can be assembled in the plastid transformants. Chlorophyll fluorescence measurements showed that dark reduction of the plastoquinone pool by stromal reductants was impaired in ndhB-inactivated plants. Both the phenotype and photosynthetic performance of the plastid transformants was completely normal under favorable conditions. However, an enhanced growth retardation of ndhB-inactivated plants was revealed under humidity stress conditions causing a moderate decline in photosynthesis via stomatal closure. This distinctive phenotype was mimicked under normal humidity by spraying plants with abscisic acid. Measurements of CO 2 fixation demonstrated an enhanced decline in photosynthesis in the mutant plants under humidity stress, which could be restored to wild-type levels by elevating the external CO 2 concentration. These results suggest that the plastid NAD(P)H:plastoquinone oxidoreductase in tobacco performs a significant physiological role by facilitating photosynthesis at moderate CO 2 limitation.

) were used to study the role of the NADH-dehydrogenase complex (NDH) during photosynthesis and particularly the involvement of this complex in cyclic electron flow around photosystem I (PSI). Photosynthetic activity was determined on leaf discs by measuring CO 2 exchange and chlorophyll fluorescence quenchings during a dark-to-light transition. In the absence of treatment, both non-photochemical and photochemical fluorescence quenchings were similar in ndhB Ϫ and wild type (WT). When leaf discs were treated with 5 m antimycin A, an inhibitor of cyclic electron flow around PSI, both quenchings were strongly affected. At steady state, maximum photosynthetic electron transport activity was inhibited by 20% in WT and by 50% in ndhB Ϫ . Under non-photorespiratory conditions (2% O 2 , 2,500 L L Ϫ1 CO 2 ), antimycin A had no effect on photosynthetic activity of WT, whereas a 30% inhibition was observed both on quantum yield of photosynthesis assayed by chlorophyll fluorescence and on CO 2 assimilation in ndhB Ϫ . The effect of antimycin A on ndhB Ϫ could not be mimicked by myxothiazol, an inhibitor of the mitochondrial cytochrome bc 1 complex, therefore showing that it is not related to an inhibition of the mitochondrial electron transport chain but rather to an inhibition of cyclic electron flow around PSI. We conclude to the existence of two different pathways of cyclic electron flow operating around PSI in higher plant chloroplasts. One of these pathways, sensitive to antimycin A, probably involves ferredoxin plastoquinone reductase, whereas the other involves the NDH complex. The absence of visible phenotype in ndhB Ϫ plants under normal conditions is explained by the complement of these two pathways in the supply of extra-ATP for photosynthesis.During oxygenic photosynthesis of C 3 plants, both photosystem II (PSII) and photosystem I (PSI) cooperate to achieve NADP ϩ reduction using water as an electron donor and generate a trans-membrane proton gradient driving ATP synthesis. Although NADP ϩ reduction is recognized to be dependent on the activity of both photosystems through electron transport reactions of the "Z" scheme (Hill and Bendall, 1960;Redding et al., 1999), it has early been reported from studies on isolated thylakoids that ATP could be produced by the sole PSI through cyclic electron transfer reactions (Arnon, 1959). The cyclic electron flow around PSI has been extensively studied in thylakoids and/or chloroplasts of C 3 plants (for review, see Fork and Herbert, 1993; Bendall and Manasse, 1995). This mechanism has been suggested to provide ATP for a variety of cellular processes, including stress adaptation (Havaux et al., 1991) and CO 2 fixation (Furbank and Horton, 1987; Herbert et al., 1990). During photosynthetic CO 2 fixation, both NADPH and ATP are used to regenerate ribulose-1,5-bisphosphate and allow functioning of the photosynthetic carbon reduction cycle (Calvin cycle). In the absence of Q cycle, when one NADPH is produced by linear electron transport reactions, four H ϩ are released in ...

A T7 promoter-controlled transgene, AbL, encoding a camel single-domain antibody fragment that binds to the model antigen chicken egg-white lysozyme was introduced into the plastid genome of tobacco. AbL expression was activated in the transplastomic line by introducing a nuclear transgene, ST7, encoding a light-regulated plastid-targeted T7RNAP by cross-pollination. The resulting AbL x ST7 progeny seedlings developed a pale-green phenotype and ceased growth soon after germination. High levels of AbL transcripts accumulated in AbL x ST7 seedlings and expression of functional AbL antibody was detected by ELISA. Transplastomic AbL plants were also crossed with nuclear-transformed tobacco plants containing a salicylic acid-inducible transgene encoding a plastid-targeted T7RNAP (PR-T7 transgene). The resulting AbL x PR-T7 progeny were wild-type in appearance but were slow growing and prone to wilting even when provided with adequate water. Although AbL transcription was inducible by treating AbL x PR-T7 leaves with salicylic acid, high levels of T7RNAP-dependent AbL transcripts also accumulated in the absence of induction. However, AbL antibody did not accumulate at levels detectable by immunoblotting or ELISA in AbL x PR-T7 plants despite the fact that total leaf RNA containing AbL transcripts was capable of directing AbL antibody synthesis in an E. coli-derived in vitro translation system.

SummaryNicotiana plumbaginifolia protoplasts were directly transformed by PEG treatment with a cloned 16s rRNA gene isolated from a double antibiotic-resistant Nicotiana tabacum plastid mutant. Putative plastid transformants were selected in cell culture by their spectinomycin resistance and identified by their unselected streptomycin resistance. Alternatively, cell lines were selected in the presence of both antibiotics. The cell line (and its regenerated plants) selected solely for spectinomycin resistance demonstrated an extensive segregation of streptomycin resistance in subsequent tests, while the double-selected line showed stable resistance for both antibiotics. The resistance markers were inherited maternally. In the putative plastid transformants the origin of the resistance mutations was identified by the absence of an Aatll site, missing in the donor N. tabacum plastid gene (spectinomycin resistance site) but present in that of wild-type N. plumbaginifolia, and a sequence analysis of the particular nucleotide changes in both resistance sites. Restriction enzyme analysis of total plastid DNA (ptDNA), and the recloning and full sequencing of the fragment introduced, investigated in one of the plastid transformants, showed no DNA rearrangements accompanied with the integration process. Sequence analysis indicated a targeted, homologous integration of the DNA fragment introduced but an unexpectedly complete homology of the parental ptDNA sequences in this region prevented the

The salutary effects of resveratrol on cecal ligation and puncture-induced myocardial dysfunction are associated with increased peroxisome proliferator-activated receptor-γ coactivator 1a abundance and function. Preservation of myocardial energy production capacity, prevention of secondary injury, mitigation of inflammation, and reversal of sepsis-induced myocardial remodeling are likely to underlie its beneficial effects. This however, does not result in improved survival.

a b s t r a c tObjectives: The objectives of this study were to: (1) explore the proportion of HTx centers that have a multidisciplinary team and (2) assess the relationship between multidisciplinarity and the level of chronic illness management (CIM). Background: The International Society for Heart and Lung Transplantation (ISHLT) recommends a multidisciplinary approach in heart transplant (HTx) follow-up care but little is known regarding the proportion of HTx centers that meet this recommendation and the impact on patient care. HTx centers

Shortage of breeding sites is an important limiting factor of bird populations. Artificial breeding platforms, nest-boxes or man-made twig nests often present solutions with remarkable results, however long-term sustainability of these populations remains to be resolved. Furthermore, the question whether the inference of results of studies conducted on birds breeding in artificial breeding sites can be generalized to other populations, still remains open. Here we present the history, and the results of a 20 year old (1995-2015) nest-box programme initiated to increase potential breeding possibilities of Red-footed Falcons in an area, where nest-site shortage was a severe limiting factor. We show how various other species (Jackdaws, Kestrels and Long-eared Owls) have utilized these resources, and present descriptive statistics on their reproductive performance. Analysing the data of a total of 1432 breeding attempts, we show that Red-footed Falcons have similar clutch sizes, and nesting success (i.e. ratio of nests with at least on fledgling), however fledging success (ratio of the number of eggs/fledged nestlings) was different in artificial nest-boxes. When we excluded closed box types from artificial nests, this difference was not apparent. In case of Kestrels (n=1626 breeding attempts) clutch size was significantly higher in artificial nests, while we found no difference in fledging or nesting success. When only comparing open boxes to natural nests, the difference in clutch size was no longer significant. We also analysed the effect of nest box design on reproductive parameters of the two species using regression trees. Inter annual effects were the most important in shaping clutch size and fledging rate of both falcon species, however we also found nest-box design effects, but only in Red-footed Falcons. In years when mean clutch size was high, these birds had lower clutch size in an older, darker nest-box type compared to an alternative design, and to open boxes. However, fledging rate in the same years was lower for both open boxes and older nest-boxes. We conclude that artificial colonies are an important and successful tool in Red-footed Falcon conservation, and that the breeding parameters measured in artificial colonies depend on nest-box design. We present correlative evidence that closed boxes have a significant positive species specific effect on reproduction, probably due to their protection against weather. We also show that birds may have a preference for a certain nest-box design, and that the breeding success in the less favoured box type may be similar to that in open nests. We recommend that future studies incorporate nest-type and nest-box design effects in all comparisons made on reproductive performance in case of Red-footed Falcons and Kestrels.

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