ENEA Casaccia Research Centre

BACKGROUND: The sperm chromatin structure assay (SCSA) has been suggested as a predictor of fertility in vivo as well as in vitro. The available data however, have been based on limited numbers of treatments. We aimed to define the clinical role of SCSA in assisted reproduction. METHODS: A total of 998 cycles [387 intrauterine insemination (IUI), 388 IVF and 223 ICSI] from 637 couples were included. SCSA results were expressed as DNA fragmentation index (DFI) and high DNA stainable (HDS) cell fractions. Outcome parameters were biochemical pregnancy (BP), clinical pregnancy (CP) and delivery (D). RESULTS: For IUI, the odds ratios (ORs) for BP, CP and D were significantly lower for couples with DFI >30% as compared with those with DFI < or =30%. No statistical difference between the outcomes of ICSI versus IVF in the group with DFI < or =30% was seen. In the DFI >30% group, the results of ICSI were significantly better than those of IVF. CONCLUSIONS: DFI can be used as an independent predictor of fertility in couples undergoing IUI. As a result, we propose that all infertile men should be tested with SCSA as a supplement to the standard semen analysis. When DFI exceeds 30%, ICSI should be the method of choice.

Flow cytometry is a convenient and rapid method that has been used extensively for estimation of nuclear genome size in plants. In contrast to general expectations, results obtained in different laboratories showed some striking discrepancies. The aim of this joint experiment was to test the reliability and reproducibility of methods. Care was taken to avoid a bias due to the quantity of DNA in the nucleus, the procedure for nuclei isolation or the type of instrument. Nuclear DNA content was estimated in nine plant species representing a typical range of genome size (2C=approx. 0.3–30 pg DNA). Each of the four laboratories involved in this study used a different buffer and/or procedure for nuclei isolation. Two laboratories used arc lamp-based instruments while the other two used laser-based instruments. The results obtained after nuclei staining with propidium iodide (a DNA intercalator) agreed well with those obtained using Feulgen densitometry. On the other hand, results obtained after staining with DAPI (binding preferentially to AT-rich regions) did not agree with those obtained using Feulgen densitometry. Small, but statistically significant, differences were found between data obtained with individual instruments. Differences between the same type of instruments were negligible, while larger differences were observed between lamp- and laser-based instruments. Ratios of fluorescence intensity obtained by laser instruments were higher than those obtained by lamp-based cytometers or by Feulgen densitometry. The results obtained in this study demonstrate that flow cytometry with DNA intercalators is a reliable method for estimation of nuclear genome size in plants. However, the study confirmed an urgent need for an agreement on standards. Given the small but systematic differences between different types of flow cytometers, analysis of very small differences in genome size should be made in the same laboratory and using the same instrument.

BACKGROUND: Potato is a major staple food, and modification of its provitamin content is a possible means for alleviating nutritional deficiencies. beta-carotene is the main dietary precursor of vitamin A. Potato tubers contain low levels of carotenoids, composed mainly of the xanthophylls lutein, antheraxanthin, violaxanthin, and of xanthophyll esters. None of these carotenoids have provitamin A activity. RESULTS: We silenced the first dedicated step in the beta-epsilon- branch of carotenoid biosynthesis, lycopene epsilon cyclase (LCY-e), by introducing, via Agrobacterium-mediated transformation, an antisense fragment of this gene under the control of the patatin promoter. Real Time measurements confirmed the tuber-specific silencing of Lcy-e. Antisense tubers showed significant increases in beta-beta-carotenoid levels, with beta-carotene showing the maximum increase (up to 14-fold). Total carotenoids increased up to 2.5-fold. These changes were not accompanied by a decrease in lutein, suggesting that LCY-e is not rate-limiting for lutein accumulation. Tuber-specific changes in expression of several genes in the pathway were observed. CONCLUSION: The data suggest that epsilon-cyclization of lycopene is a key regulatory step in potato tuber carotenogenesis. Upon tuber-specific silencing of the corresponding gene, beta-beta-carotenoid and total carotenoid levels are increased, and expression of several other genes in the pathway is modified.

The central dogma of radiation biology, that biological effects of ionizing radiation are a direct consequence of DNA damage occurring in irradiated cells, has been challenged by observations that genetic/epigenetic changes occur in unexposed "bystander cells" neighboring directly-hit cells, due to cell-to-cell communication or soluble factors released by irradiated cells. To date, the vast majority of these effects are described in cell-culture systems, while in vivo validation and assessment of biological consequences within an organism remain uncertain. Here, we describe the neonatal mouse cerebellum as an accurate in vivo model to detect, quantify, and mechanistically dissect radiation-bystander responses. DNA double-strand breaks and apoptotic cell death were induced in bystander cerebellum in vivo. Accompanying these genetic events, we report bystander-related tumor induction in cerebellum of radiosensitive Patched-1 (Ptch1) heterozygous mice after x-ray exposure of the remainder of the body. We further show that genetic damage is a critical component of in vivo oncogenic bystander responses, and provide evidence supporting the role of gap-junctional intercellular communication (GJIC) in transmission of bystander signals in the central nervous system (CNS). These results represent the first proof-of-principle that bystander effects are factual in vivo events with carcinogenic potential, and implicate the need for re-evaluation of approaches currently used to estimate radiation-associated health risks.

Standard sperm parameters have a limited power for prediction of the chance of natural conception. Recent studies have indicated that the sperm chromatin structure assay (SCSA) DNA fragmentation index (DFI), a measure for the fraction of sperms with DNA damage, is associated with fertility in vivo. The aim of this study was to evaluate the value of this parameter for prediction of infertility. One hundred and twenty-seven men from infertile couples with no known female factor and 137 men with proven fertility were included. Semen analysis was performed as recommended by the WHO. DFI was assessed using SCSA. Logistic binary regression was used to compute the odds ratios (OR) for infertility. As compared with men with a DFI <10%, men with a DFI between 10% and 20% had an increased risk for infertility (OR 2.5, 95% CI: 1.0-6.1). This was also true for men with a DFI >20% (OR 8.4; 95% CI: 3.0-23). In men with normal standard semen parameters (sperm concentration, motility and morphology) the OR for infertility was increased with DFI >20% (OR 5.1, 95% CI: 1.2-23), whereas if one of the standard semen parameters was abnormal, the OR for infertility was increased already at DFI above 10% (OR 16, 95% CI: 4.2-60). We conclude that SCSA DFI adds to the value of semen analysis in prediction of the chance of natural conception.

BACKGROUND: Carotenoids are plant metabolites which are not only essential in photosynthesis but also important quality factors in determining the pigmentation and aroma of flowers and fruits. To investigate the regulation of carotenoid metabolism, as related to norisoprenoids and other volatile compounds in peach (Prunus persica L. Batsch.), and the role of carotenoid dioxygenases in determining differences in flesh color phenotype and volatile composition, the expression patterns of relevant carotenoid genes and metabolites were studied during fruit development along with volatile compound content. Two contrasted cultivars, the yellow-fleshed 'Redhaven' (RH) and its white-fleshed mutant 'Redhaven Bianca' (RHB) were examined. RESULTS: The two genotypes displayed marked differences in the accumulation of carotenoid pigments in mesocarp tissues. Lower carotenoid levels and higher levels of norisoprenoid volatiles were observed in RHB, which might be explained by differential activity of carotenoid cleavage dioxygenase (CCD) enzymes. In fact, the ccd4 transcript levels were dramatically higher at late ripening stages in RHB with respect to RH. The two genotypes also showed differences in the expression patterns of several carotenoid and isoprenoid transcripts, compatible with a feed-back regulation of these transcripts. Abamine SG - an inhibitor of CCD enzymes - decreased the levels of both isoprenoid and non-isoprenoid volatiles in RHB fruits, indicating a complex regulation of volatile production. CONCLUSIONS: Differential expression of ccd4 is likely to be the major determinant in the accumulation of carotenoids and carotenoid-derived volatiles in peach fruit flesh. More in general, dioxygenases appear to be key factors controlling volatile composition in peach fruit, since abamine SG-treated 'Redhaven Bianca' fruits had strongly reduced levels of norisoprenoids and other volatile classes. Comparative functional studies of peach carotenoid cleavage enzymes are required to fully elucidate their role in peach fruit pigmentation and aroma.

BACKGROUND: Water stress during grain filling has a marked effect on grain yield, leading to a reduced endosperm cell number and thus sink capacity to accumulate dry matter. The bread wheat cultivar Chinese Spring (CS), a Chinese Spring terminal deletion line (CS_5AL-10) and the durum wheat cultivar Creso were subjected to transcriptional profiling after exposure to mild and severe drought stress at the grain filling stage to find evidences of differential stress responses associated to different wheat genome regions. RESULTS: The transcriptome analysis of Creso, CS and its deletion line revealed 8,552 non redundant probe sets with different expression levels, mainly due to the comparisons between the two species. The drought treatments modified the expression of 3,056 probe sets. Besides a set of genes showing a similar drought response in Creso and CS, cluster analysis revealed several drought response features that can be associated to the different genomic structure of Creso, CS and CS_5AL-10. Some drought-related genes were expressed at lower level (or not expressed) in Creso (which lacks the D genome) or in the CS_5AL-10 deletion line compared to CS. The chromosome location of a set of these genes was confirmed by PCR-based mapping on the D genome (or the 5AL-10 region). Many clusters were characterized by different level of expression in Creso, CS and CS_AL-10, suggesting that the different genome organization of the three genotypes may affect plant adaptation to stress. Clusters with similar expression trend were grouped and functional classified to mine the biological mean of their activation or repression. Genes involved in ABA, proline, glycine-betaine and sorbitol pathways were found up-regulated by drought stress. Furthermore, the enhanced expression of a set of transposons and retrotransposons was detected in CS_5AL-10. CONCLUSION: Bread and durum wheat genotypes were characterized by a different physiological reaction to water stress and by a substantially different molecular response. The genome organization accounted for differences in the expression level of hundreds of genes located on the D genome or controlled by regulators located on the D genome. When a genomic stress (deletion of a chromosomal region) was combined with low water availability, a molecular response based on the activation of transposons and retrotransposons was observed.

Abstract Recent snow accumulation rate is a key quantity for ice-core and mass-balance studies. Several accumulation measurement methods (stake farm, fin core, snow-radar profiling, surface morphology, remote sensing) were used, compared and integrated at eight sites along a transect from Terra Nova Bay to Dome C, East Antarctica, to provide information about the spatial and temporal variability of snow accumulation. Thirty-nine cores were dated by identifying tritium/b marker levels (1965_66) and non-sea-salt (nss) SO 4 2_ spikes of the Tambora (Indonesia) volcanic event (1816) in order to provide information on temporal variability. Cores were linked by snow radar and global positioning system surveys to provide detailed information on spatial variability in snow accumulation. Stake-farm and ice-core accumulation rates are observed to differ significantly, but isochrones (snow radar) correlate well with ice-core derived accumulation. The accumulation/ablation pattern from stake measurements suggests that the annual local noise (metre scale) in snow accumulation can approach 2 years of ablation and more than four times the average annual accumulation, with no accumulation or ablation for a 5 year period in up to 40% of cases. The spatial variability of snow accumulation at the kilometre scale is one order of magnitude higher than temporal variability at the multi-decadal/secular scale. Stake measurements and firn cores at Dome C confirm an approximate 30% increase in accumulation over the last two centuries, with respect to the average over the last 5000 years

BACKGROUND: Beta-carotene is the main dietary precursor of vitamin A. Potato tubers contain low levels of carotenoids, composed mainly of the xanthophylls lutein (in the beta-epsilon branch) and violaxanthin (in the beta-beta branch). None of these carotenoids have provitamin A activity. We have previously shown that tuber-specific silencing of the first step in the epsilon-beta branch, LCY-e, redirects metabolic flux towards beta-beta carotenoids, increases total carotenoids up to 2.5-fold and beta-carotene up to 14-fold. RESULTS: In this work, we silenced the non-heme beta-carotene hydroxylases CHY1 and CHY2 in the tuber. Real Time RT-PCR measurements confirmed the tuber-specific silencing of both genes . CHY silenced tubers showed more dramatic changes in carotenoid content than LCY-e silenced tubers, with beta-carotene increasing up to 38-fold and total carotenoids up to 4.5-fold. These changes were accompanied by a decrease in the immediate product of beta-carotene hydroxylation, zeaxanthin, but not of the downstream xanthophylls, viola- and neoxanthin. Changes in endogenous gene expression were extensive and partially overlapping with those of LCY-e silenced tubers: CrtISO, LCY-b and ZEP were induced in both cases, indicating that they may respond to the balance between individual carotenoid species. CONCLUSION: Together with epsilon-cyclization of lycopene, beta-carotene hydroxylation is another regulatory step in potato tuber carotenogenesis. The data are consistent with a prevalent role of CHY2, which is highly expressed in tubers, in the control of this step. Combination of different engineering strategies holds good promise for the manipulation of tuber carotenoid content.

BACKGROUND: Perfluorinated compounds (PFCs) have been suspected to adversely affect human reproductive health. The aim of this study was to investigate the associations between PFC exposure and male semen quality. METHODS: PFCs were measured in serum from 588 partners of pregnant women from Greenland, Poland and Ukraine who provided a semen sample, using liquid chromatography tandem mass spectrometry. Perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) could be detected in >97% of the samples. The associations between levels of these compounds and semen volume, sperm concentration, total sperm count, motility and morphology were assessed. RESULTS: Across countries, sperm concentration, total sperm count and semen volume were not consistently associated with PFOS, PFOA, PFHxS or PFNA levels. The proportion of morphologically normal cells was 35% lower [95% confidence interval (CI): 4-66%) for the third tertile of PFOS exposure as compared with the first. A similar reduction was found in relation to increasing PFHxS levels. At the third PFOA exposure tertile, the percentage of motile spermatozoa was 19% (95% CI: 1 to 39%) higher than in the first. CONCLUSIONS: The most robust finding in the present study was the negative associations between PFOS exposure and sperm morphology suggesting adverse effects of PFOS on semen quality, possibly due to interference with the endocrine activity or sperm membrane function. It cannot be excluded that this association and the positive association between PFOA and semen motility, which was not consistent across countries, might represent a chance finding due to the multiple statistical tests being performed.

In green plants, the xanthophyll carotenoid zeaxanthin is synthesized transiently under conditions of excess light energy and participates in photoprotection. In the Arabidopsis lut2 npq2 double mutant, all xanthophylls were replaced constitutively by zeaxanthin, the only xanthophyll whose synthesis was not impaired. The relative proportions of the different chlorophyll antenna proteins were strongly affected with respect to the wild-type strain. The major antenna, LHCII, did not form trimers, and its abundance was strongly reduced as was CP26, albeit to a lesser extent. In contrast, CP29, CP24, LHCI proteins, and the PSI and PSII core complexes did not undergo major changes. PSII-LHCII supercomplexes were not detectable while the PSI-LHCI supercomplex remained unaffected. The effect of zeaxanthin accumulation on the stability of the different Lhc proteins was uneven: the LHCII proteins from lut2 npq2 had a lower melting temperature as compared with the wild-type complex while LHCI showed increased resistance to heat denaturation. Consistent with the loss of LHCII, light-state 1 to state 2 transitions were suppressed, the photochemical efficiency in limiting light was reduced and photosynthesis was saturated at higher light intensities in lut2 npq2 leaves, resulting in a photosynthetic phenotype resembling that of high light-acclimated leaves. Zeaxanthin functioned in vivo as a light-harvesting accessory pigment in lut2 npq2 chlorophyll antennae. As a whole, the in vivo data are consistent with the results obtained by using recombinant Lhc proteins reconstituted in vitro with purified zeaxanthin. While PSII photoinhibition was similar in wild type and lut2 npq2 exposed to high light at low temperature, the double mutant was much more resistant to photooxidative stress and lipid peroxidation than the wild type. The latter observation is consistent with an antioxidant and lipid protective role of zeaxanthin in vivo. In green plants, the xanthophyll carotenoid zeaxanthin is synthesized transiently under conditions of excess light energy and participates in photoprotection. In the Arabidopsis lut2 npq2 double mutant, all xanthophylls were replaced constitutively by zeaxanthin, the only xanthophyll whose synthesis was not impaired. The relative proportions of the different chlorophyll antenna proteins were strongly affected with respect to the wild-type strain. The major antenna, LHCII, did not form trimers, and its abundance was strongly reduced as was CP26, albeit to a lesser extent. In contrast, CP29, CP24, LHCI proteins, and the PSI and PSII core complexes did not undergo major changes. PSII-LHCII supercomplexes were not detectable while the PSI-LHCI supercomplex remained unaffected. The effect of zeaxanthin accumulation on the stability of the different Lhc proteins was uneven: the LHCII proteins from lut2 npq2 had a lower melting temperature as compared with the wild-type complex while LHCI showed increased resistance to heat denaturation. Consistent with the loss of LHCII, light-state 1 to state 2 transitions were suppressed, the photochemical efficiency in limiting light was reduced and photosynthesis was saturated at higher light intensities in lut2 npq2 leaves, resulting in a photosynthetic phenotype resembling that of high light-acclimated leaves. Zeaxanthin functioned in vivo as a light-harvesting accessory pigment in lut2 npq2 chlorophyll antennae. As a whole, the in vivo data are consistent with the results obtained by using recombinant Lhc proteins reconstituted in vitro with purified zeaxanthin. While PSII photoinhibition was similar in wild type and lut2 npq2 exposed to high light at low temperature, the double mutant was much more resistant to photooxidative stress and lipid peroxidation than the wild type. The latter observation is consistent with an antioxidant and lipid protective role of zeaxanthin in vivo. When vascular plants or green algae are suddenly exposed to high light, the diepoxide xanthophyll violaxanthin is rapidly converted via the intermediate antheraxanthin to the epoxide-free zeaxanthin under the action of the enzyme violaxanthin deepoxidase (1Yamamoto H.J. Pure Appl. Chem. 1979; 51: 639-648Google Scholar, 2Eskling M. Arvidsson P.-O. Akerlund H.E. Physiol. Plant. 1997; 100: 806-816Google Scholar). The latter enzyme is located in the lumen of the thylakoids and binds to the thylakoid membrane in response to lumen acidification in the light (3Hager A. Holocher K. Planta. 1994; 192: 581-589Google Scholar). Upon return to light limiting conditions, zeaxanthin is epoxidized back to violaxanthin by a zeaxanthin epoxidase enzyme localized on the stromal side of the thylakoid membranes. These stoichiometric and cyclic conversions of violaxanthin, antheraxanthin, and zeaxanthin are called the violaxanthin cycle and have profound effects on light harvesting and light energy utilization in Photosystem (PS) 1The abbreviations used are: PS, photosystem; LHC (I and II), light-harvesting complex (of PSI and PSII); Lhca and Lhcb, protein component of LHCI and LHCII, respectively; CP24, CP26 and CP29, minor LHCII (Lhcb6, Lhcb5, and Lhcb4, respectively); NPQ, nonphotochemical quenching; WT, wild type; TL, thermoluminescence; Φ, quantum yield of O2 evolution; E, Emerson enhancement; DM, dodecyl-d-maltoside. II. It is well established that zeaxanthin synthesis and lumen acidification in high light act synergistically to convert PSII from a state of maximum efficiency of light harvesting to a state of high energy dissipation in the form of heat (4Horton P. Ruban A.V. Walters R.G. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1996; 47: 655-684Google Scholar, 5Demming-Adams B. Adams III, W.W. Nature. 2000; 403: 371-374Google Scholar, 6Müller P. Li X.-P. Niyogi K.K. Plant Physiol. 2001; 125: Scholar). The latter is as a nonphotochemical of chlorophyll is the of the photosynthetic the PSII from its resistance to as in Arabidopsis K.K. Plant Scholar, M. Niyogi K.K. A. Scholar, M. K. Planta. 2001; Scholar). that zeaxanthin the resistance to thylakoid membrane lipid peroxidation by a from NPQ, to M. Niyogi K.K. A. Scholar, M. Niyogi K.K. Plant Physiol. 2000; Scholar, P. M. Niyogi K.K. Plant Physiol. Scholar, Niyogi K.K. Plant Scholar). The xanthophyll cycle and the protective under conditions of light M. K. Planta. 2001; Scholar, Scholar). Zeaxanthin is from green plants under conditions, and transiently only under excess light the of zeaxanthin in the chlorophyll in a of of Arabidopsis an the effects of carotenoid on the and of the photosynthetic M. 1996; Scholar, Plant Physiol. 1997; 639-648Google Scholar, Scholar). In the Arabidopsis zeaxanthin epoxidase is not accumulation of zeaxanthin at the of the antheraxanthin, violaxanthin, and Plant Scholar, A. Scholar). in the mutant, zeaxanthin of the xanthophyll M. 1996; Scholar). xanthophyll had effects on the photosynthetic of the leaves, a stability of the LHCII complexes chlorophyll antenna of and a LHCII and the minor LHCII were M. 1996; Scholar, Plant Physiol. 1997; 639-648Google Scholar, P. P. from to Scholar). the are in the is synthesized from a of the have a of a phenotype and conditions Niyogi K.K. Plant a of is not a is synthesized in that the mutant is not to K.K. Plant Scholar). are reduced to as as xanthophyll are is more than the was with the lut2 mutant, in and the resulting double mutant, not xanthophyll carotenoid zeaxanthin, was its photosynthetic and high light of all xanthophylls by zeaxanthin affected the PSII antenna resulting in a photosynthetic phenotype in that of high light-acclimated leaves, and the of the to photooxidative In to the of proteins the PSII antenna the stability of the Lhca proteins of PSI to by zeaxanthin. Plant and wild type the double mutant lut2 and the mutant of Arabidopsis were under conditions of light of temperature and relative The and were obtained from the Arabidopsis and a of lut2 was from the were exposed to high light of at as M. B. Plant Physiol. Scholar). in were and by as in M. B. Plant Physiol. Scholar). were to that a of the was used in the and was replaced by in the The protein of thylakoid was with a protein using as a The and of thylakoid were with an and a were from thylakoids in a as Scholar). of the were in and of and was the by and Biol. Chem. Scholar). The of the The of the from by a from to were with and a of of with of was The was and was were at under a of of the thylakoid complexes was by Biol. Chem. 2001; Scholar). to of chlorophyll were with and in 1 of by 1 The were at to and by in a and at at The green of the were with a and were to with a as Scholar). The of the proteins was from the of the with The was with of recombinant membrane proteins by in were membranes. were with the CP26 or and were with intensities were using the were by as K. P. Planta. 1996; Scholar). 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Plant Physiol. Plant Mol. Biol. 1994; light of was obtained by light an and light of was obtained with an The of the green and light was that the of light by the by the of the was similar in The quantum yield of O2 was by the the of the and the of the Rev. Plant Physiol. Plant Mol. Biol. 1994; Scholar). The Emerson of O2 was in state 1 or in state 2 by a light to the light with a 2 was by the with the light and state 1 was obtained with were with a quantum by 1 was with a M. Plant Scholar). The was at a of from to The of the at was used as an of lipid peroxidation Rev. Plant Physiol. Plant Mol. Biol. 1994; Scholar, M. Plant Scholar). by was at with a O2 were with light by a light was using was in the with a of the Arabidopsis lut2 npq2 double mutant are in the xanthophylls violaxanthin, antheraxanthin, and The xanthophylls are replaced by zeaxanthin, resulting in a and a not different from the wild-type and lut2 npq2 were than wild-type leaves, and was to a of the chlorophyll and carotenoid pigment was by a in the chlorophyll a to to as the lut2 mutant Scholar, Niyogi K.K. A. Scholar). of the chlorophyll is as resulting from a in the PSII light-harvesting binds of the chlorophyll an in the that was to of the chlorophyll a to chlorophyll chlorophyll proteins in the light-harvesting recombinant LHCII complexes reconstituted with zeaxanthin as the only carotenoid have to have an increased chlorophyll as compared with LHCII Biol. Chem. pigment of Arabidopsis and lut2 npq2 are of is the xanthophyll cycle were from plants exposed to a of and were rapidly in pigment not or not or in a PSII and PSI the chlorophyll of wild-type and lut2 npq2 at K. As compared with wild lut2 npq2 a in the PSII and while the PSI was in PSII was in thylakoid The light energy PSI and PSII was in vivo using the 2 the to O2 Rev. Plant Physiol. Plant Mol. Biol. 1994; by an Arabidopsis with a light at a low of The was lower in the double mutant relative to wild a of photosynthetic O2 of its the light is by PSII and O2 are by the to When a light, by is to the light, is and O2 by the photochemical quantum of effect by the Emerson is the of the O2 in the of the light to the O2 in its Rev. Plant Physiol. Plant Mol. 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Biol. 2001; Scholar, M. Biol. Chem. Scholar). to in the temperature of the minor and was in lut2 npq2 as compared with wild a stability of Lhc of minor major from and lut2 npq2 thylakoids are of of in a of lut2 were exposed to high light stress at low temperature a that to photosynthetic in wild type and lut2 npq2 a in the PSII photochemical efficiency as by the chlorophyll PSII photoinhibition was similar in wild type and lut2 The of high light and low temperature is the of stress and photoinhibition of wild type and lut2 npq2 Arabidopsis exposed to at was by with a of In lipid peroxidation was in by a M. Plant Scholar). wild-type were to much more to photooxidative than lut2 npq2 leaves. The of the at is to the of lipid in the thylakoid M. Plant Scholar, strongly increased in wild-type in high light remained low in lut2 npq2 in high stress was on of the mutant in chlorophyll and in LHCII Plant Mol. Biol. Scholar, A. Scholar). a of the PSII antenna did not The was the lipid increased rapidly in relative to wild type. The in lut2 npq2 the carotenoid of the PSII antenna complexes is are in proportions on the antenna 2000; Scholar). Arabidopsis with xanthophyll have that the xanthophyll of is M. 1996; Scholar, Plant Physiol. 1997; 639-648Google Scholar, B. M. Plant 1996; Scholar). in vitro of recombinant Lhc proteins with purified have that is to LHCII complexes with xanthophyll zeaxanthin Biol. Chem. Scholar, M. 2001; Scholar). The that in vivo in a xanthophyll mutant all minor and major were in lut2 all were in lut2 npq2 leaves. the relative proportions of the different LHC were strongly that the different not have the to the in xanthophyll The abundance of the major LHCII was resulting a in the PSII antenna in the mutant, and effect was to a loss of and was much affected by the xanthophyll zeaxanthin had effect on the minor LHCII the and the that the of LHCII was strongly by the of zeaxanthin. LHCII and PSII supercomplexes LHCII and the minor was in the double of LHCII was in xanthophyll of Arabidopsis as the M. 1996; Scholar, Plant Physiol. 1997; 639-648Google or the lut2 mutant that the to form is the xanthophyll is In an Arabidopsis the proteins that form LHCII and the of LHCII was by CP26, was trimers, with A.V. M. P. Nature. Scholar). was not the in lut2 the abundance was not affected by the double CP26 was It is LHCII, CP26 was to form similar was in the npq2 mutant of the of the 2 npq2 Arabidopsis mutant Niyogi K.K. A. Plant Physiol. 2001; LHCII and CP26 CP24, CP29, and PSI antenna proteins did The of LHCII was not in CP26 is located at the of the supercomplex Scholar, Ruban A.V. P. and is that loss of LHCII in lut2 npq2 loss of In contrast, and are located in the and the LHCII Scholar, Ruban A.V. P. and to the loss in stability in the double mutant as a the and of the PSII antenna of the lut2 npq2 The of PSII supercomplexes and the of supercomplexes in the thylakoid membrane the quantum efficiency of the of the LHCII and CP26 abundance as well as the loss of LHCII supercomplexes in lut2 npq2 the quantum efficiency of PSII as well as the of the of zeaxanthin in the chlorophyll PSII in a state of energy dissipation of the type zeaxanthin in III, W.W. A. B. Plant Physiol. Scholar). of Zeaxanthin in not LHCII trimers, are the of B. 2000; Scholar). It is that is by the of in form to the thylakoid the is located M. B. Plant Physiol. Scholar). is in to a stability of LHCII in lut2 npq2 resulting a low LHCII The of 2 and in lut2 npq2 relative to wild type that the of LHCII was more affected by the double than the LHCII not to to in the lut2 mutant, is by a loss of LHCII the stability of is not and In contrast, in the mutant, violaxanthin and are replaced by zeaxanthin and the of LHCII in is reduced M. 1996; Scholar, Plant Physiol. 1997; 639-648Google Scholar, Scholar). a different was in the mutant the major effect was in CP26, with the LHCII affected P. P. from to Scholar). and not LHCII was affected in different zeaxanthin to an in the and that the of LHCII M. A. Ruban A.V. A. P. Scholar). The in the of the with the LHCII A. 1996; have to to a of the violaxanthin the of zeaxanthin in the 1997; 51: Scholar). It is to the synthesis of zeaxanthin, not only as a that rapidly light harvesting (4Horton P. Ruban A.V. Walters R.G. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1996; 47: 655-684Google as a that of the PSII antenna to high light conditions by LHCII LHCII stability and LHCII In the xanthophyll cycle as a is by the the photosynthetic of lut2 npq2 and high light-acclimated wild-type leaves. of vascular plants to high light conditions is by a in the major LHCII and an in the photosynthetic R.G. P. Planta. 1994; Scholar). were in lut2 npq2 and in high light was to a in and CP26 while the and were to Walters R.G. P. Planta. 2001; Scholar). of the PSII antenna proteins was in lut2 npq2 wild type. of the photosynthetic of lut2 npq2 of high light Arabidopsis plants, the that zeaxanthin is in the of the PSII antenna to the light is by with with the mutant at low and light intensities have that the and are more in mutant as compared with wild type not in with In of in complexes reconstituted in vitro are similar to wild type LHCII with respect to energy and Mol. Biol. 2001; Scholar). In major of the as antenna was in compared with wild-type LHCII Scholar). is in vivo by on and by of The high photochemical of lut2 npq2 in green light and the the and showed that zeaxanthin functioned as a light-harvesting accessory pigment that was to energy to the that zeaxanthin was to antenna proteins and that zeaxanthin was as in the membrane lipid the lut2 npq2 LHCII were to than wild-type LHCII and is consistent with in vitro of the stability of reconstituted with zeaxanthin Mol. Biol. 2001; Scholar). In to the antenna of PSI was not affected by the lut2 npq2 double that the stability of the was not by zeaxanthin. have the stability of recombinant LHCI proteins and in vitro with zeaxanthin or violaxanthin, and have compared the with of LHCI complexes in Scholar, Biol. Chem. Scholar). As in zeaxanthin increased the of and was not violaxanthin was in vitro and in vivo that the PSI antenna is to the of all xanthophylls by zeaxanthin and that and Lhca proteins of violaxanthin zeaxanthin, is consistent with the that LHCI violaxanthin with zeaxanthin in vivo and in vitro with high efficiency Biol. Chem. stability of recombinant LHCI proteins with different carotenoid of Biol. Chem. in a lut2 npq2 to vitro have that LHCII reconstituted with zeaxanthin is as to as wild-type LHCII Mol. Biol. 2001; Scholar). The of PSII was in vivo in When exposed to excess light energy by the of high light and low temperature, the of PSII as by the was similar in wild-type and mutant was with a of by photooxidative of thylakoid as with a of lipid peroxidation lipid peroxidation much more rapidly in wild type than in lut2 a strongly increased of the double mutant to The of the double mutant by its photosynthetic in high light at low temperature was similar in wild-type and lut2 npq2 and energy dissipation via the is in lut2 npq2 as is in the lut2 mutant Scholar, Niyogi K.K. A. Scholar). is that the high of the mutant to the of the PSII antenna In with green algae Appl. Scholar, A. Planta. antenna not vascular plants from A. Plant Physiol. Scholar, 1994; Scholar). a chlorophyll mutant was not more to high light stress than wild-type M. Plant Physiol. 1997; Scholar). As in to was not in the chlorophyll Arabidopsis mutant that is in LHCII the high of lut2 npq2 is to the of high of zeaxanthin in the of Arabidopsis have its role in the used by plants to excess light energy (4Horton P. Ruban A.V. Walters R.G. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1996; 47: 655-684Google Scholar, 6Müller P. Li X.-P. Niyogi K.K. Plant Physiol. 2001; 125: zeaxanthin of membrane lipid peroxidation M. Niyogi K.K. A. Scholar, M. K. Planta. 2001; Scholar). was by P. M. Niyogi K.K. Plant Physiol. showed that zeaxanthin the of an Arabidopsis mutant to photooxidative plants the enzyme high of zeaxanthin and an increased to photooxidative stress P. Nature. Scholar, Plant Mol. Biol. Scholar). that a mutant is to photooxidative stress is consistent with the antioxidant and lipid of zeaxanthin. It is not zeaxanthin synthesized the of the xanthophyll cycle O2 and lipid peroxidation as in the lipid or to are data that are with a zeaxanthin and thylakoid membrane M. K. Planta. 2001; Scholar, Niyogi K.K. Plant Scholar, M. B. Plant Physiol. Scholar). zeaxanthin is located in the light-harvesting of lut2 npq2 and is to and a of zeaxanthin to as in the lipid the pigment in the of lut2 npq2 was in zeaxanthin, with a of The latter is much higher than the the zeaxanthin were from LHC denaturation. have and the major LHCII or in lut2 npq2 or wild to the that zeaxanthin to the Biol. Chem. Scholar). the of zeaxanthin from of zeaxanthin CP26, CP29, CP24, and LHCII in relative yield a of and a zeaxanthin of while to of zeaxanthin in of lut2 npq2 as in vivo. wild type a lower of the of in the and the of in the in lut2 npq2 are of In wild the of is much These of in the of zeaxanthin from a with low the carotenoid in the in the membrane lipid and to the protein in with the in the lipid a that of zeaxanthin photooxidative stress in green algae Niyogi K.K. Plant Scholar). The zeaxanthin in lut2 npq2 thylakoid by different by as a lipid peroxidation A. K. K. or by with P. Scholar). have to the antioxidant of zeaxanthin under conditions the of the xanthophyll in the protein the lipid or The of violaxanthin to zeaxanthin is in the of the thylakoid M. Niyogi K.K. A. that the of high of zeaxanthin in the lut2 npq2 mutant increased the thylakoid to photooxidative the photosynthetic of Arabidopsis was not affected by the of all xanthophylls by zeaxanthin, that the of the is a reduced to low light lut2 npq2 had a antenna that was to state had a reduced photochemical efficiency in low light and an photosynthetic in high These photosynthetic are to a and of the major

BACKGROUND: Inconsistent results have been found in previous human studies on male reproductive toxicity of persistent organochlorine pollutants. The majority of studies have been conducted among selected populations of infertility clients or among occupational cohorts including a limited number of participants. METHODS: We conducted a cross-sectional study of semen quality and serum concentration of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE) among 763 men. We included men from all regions in Greenland (n = 194), fishermen from Sweden (n = 185), inhabitants of the city of Kharkiv, Ukraine (n = 195), and inhabitants of the city of Warsaw, Poland (n = 189). Blood samples were analyzed for CB-153 and p,p'-DDE using gas chromatography-mass spectrometry and adjusted for serum lipids. RESULTS: Sperm concentration was not impaired with increasing serum CB-153 or p,p'-DDE levels in any of the separate groups or overall. Similarly, the proportion of morphologically normal sperm was not associated with either CB-153 or p,p'-DDE blood concentration. However, sperm motility was inversely related to CB-153 concentration in Greenland and the Swedish fishermen population. Across all 4 regions, the sperm motility decreased on average by 3.6% (95% confidence interval = 1.7% to 5.6%) per one-unit increase in the log of blood CB-153 (ng/g lipid). The concentration of p,p'-DDE was negatively associated with sperm motility in the Greenlandic population and in the compiled dataset. CONCLUSION: Adult exposure to persistent organochlorine pollutants within the ranges observed in the present study is not likely to cause reduction in sperm concentration or morphology. However, higher exposure may be associated with impaired sperm motility.

This paper presents a thermodynamic analysis and techno-economic assessment of a novel hybrid solar-biomass power-generation system configuration composed of an externally fired gas-turbine (EFGT) fuelled by biomass (wood chips) and a bottoming organic Rankine cycle (ORC) plant. The main novelty is related to the heat recovery from the exhaust gases of the EFGT via thermal energy storage (TES), and integration of heat from a parabolic-trough collectors (PTCs) field with molten salts as a heat-transfer fluid (HTF). The presence of a TES between the topping and bottoming cycles facilitates the flexible operation of the system, allows the system to compensate for solar energy input fluctuations, and increases capacity factor and dispatchability. A TES with two molten salt tanks (one cold at 200 °C and one hot at 370 °C) is chosen. The selected bottoming ORC is a superheated recuperative cycle suitable for heat conversion in the operating temperature range of the TES. The whole system is modelled by means of a Python-based software code, and three locations in the Mediterranean area are assumed in order to perform energy-yield analyses: Marseille in France, Priolo Gargallo in Italy and Rabat in Morocco. In each case, the thermal storage that minimizes the levelized cost of energy (LCE) is selected on the basis of the estimated solar radiation and CSP size. The results of the thermodynamic simulations, capital and operational costs assessments and subsidies (feed-in tariffs for biomass and solar electricity available in the Italian framework), allow estimating the global energy conversion efficiency and the investment profitability in the three locations. Sensitivity analyses of the biomass costs, size of PTCs, feed-in tariff and share of cogenerated heat delivered to the load are also performed. The results show that the high investment costs of the CSP section in the proposed size range and hybridization configuration allow investment profitability only in the presence of a dedicated subsidy framework such as the one available in the Italian energy market. In particular, the LCE of the proposed system is around 140 Eur/MWh (with the option to discharge the cogenerated heat) and the IRR is around 15%, based on the Italian electricity subsidy tariffs. The recovery of otherwise discharged heat to match thermal energy demand can significantly increase the investment profitability and compensate the high investment costs of the proposed technology.

The enzyme norcoclaurine synthase (NCS) catalyzes the stereospecific Pictet-Spengler cyclization between dopamine and 4-hydroxyphenylacetaldehyde, the key step in the benzylisoquinoline alkaloid biosynthetic pathway. The crystallographic structure of norcoclaurine synthase from Thalictrum flavum in its complex with dopamine substrate and the nonreactive substrate analogue 4-hydroxybenzaldehyde has been solved at 2.1A resolution. NCS shares no common features with the functionally correlated "Pictet-Spenglerases" that catalyze the first step of the indole alkaloids pathways and conforms to the overall fold of the Bet v1-like protein. The active site of NCS is located within a 20-A-long catalytic tunnel and is shaped by the side chains of a tyrosine, a lysine, an aspartic, and a glutamic acid. The geometry of the amino acid side chains with respect to the substrates reveals the structural determinants that govern the mechanism of the stereoselective Pictet-Spengler cyclization, thus establishing an excellent foundation for the understanding of the finer details of the catalytic process. Site-directed mutations of the relevant residues confirm the assignment based on crystallographic findings.

The valence band offset (VBO) at the interface CdS/Cu2ZnSnS 4 was investigated by x-ray photoelectron spectroscopy (XPS). The VBO was measured by two different procedures: an indirect method involving the measurements of the core levels together with the XPS bulk valence band (VB) spectra and a direct method involving the analysis of XPS VB spectra at the interface. The indirect method resulted in a VBO value of (-1.20 ± 0.14) eV while the direct method returned a similar value of (-1.24 ± 0.06) eV but affected by a lower uncertainty. The conduction band offset (CBO) was calculated from the measured VBO values. These two measured values of the VBO allowed us to calculate the CBO, giving (-0.30 ± 0.14) eV and (-0.34 ± 0.06) eV, respectively. These values show that the CBO has a cliff-like behaviour which could be one of the reasons for the Voc limitation in the CdS/CZTS solar cells. © 2013 IOP Publishing Ltd.

We investigated the potential performance of air pollution removal by the green infrastructures and urban forests in the city of Florence, central Italy, with a focus on the two most detrimental pollutants for human health: particulate (PM10) and ozone (O3). The spatial distribution of green infrastructures was mapped using remote sensing data. A spatial modeling approach using vegetation indices, Leaf Area Index, and local pollution concentration data was applied to estimate PM10 and O3 removal. The results are discussed to highlight the role and potential of green infrastructures and urban forests in improving air quality in Southern European cities.

The Gram-negative bacteria Pseudomonas aeruginosa and Burkholderia cenocepacia are opportunistic human pathogens that are responsible for severe nosocomial infections in immunocompromised patients and those suffering from cystic fibrosis (CF). These two bacteria have been shown to form biofilms in the airways of CF patients that make such infections more difficult to treat. Only recently have scientists begun to appreciate the complicated interplay between microorganisms during polymicrobial infection of the CF airway and the implications they may have for disease prognosis and response to therapy.To gain insight into the possible role that interaction between strains of P. aeruginosa and B. cenocepacia may play during infection, we characterised co-inoculations of in vivo and in vitro infection models. Co-inoculations were examined in an in vitro biofilm model and in a murine model of chronic infection. Assessment of biofilm formation showed that B. cenocepacia positively influenced P. aeruginosa biofilm development by increasing biomass. Interestingly, co-infection experiments in the mouse model revealed that P. aeruginosa did not change its ability to establish chronic infection in the presence of B. cenocepacia but co-infection did appear to increase host inflammatory response.Taken together, these results indicate that the co-infection of P. aeruginosa and B. cenocepacia leads to increased biofilm formation and increased host inflammatory response in the mouse model of chronic infection. These observations suggest that alteration of bacterial behavior due to interspecies interactions may be important for disease progression and persistent infection.

Tomato fruit ripening is controlled by the hormone ethylene and by a group of transcription factors, acting upstream of ethylene. During ripening, the linear carotene lycopene accumulates at the expense of cyclic carotenoids. Fruit-specific overexpression of LYCOPENE β-CYCLASE (LCYb) resulted in increased β-carotene (provitamin A) content. Unexpectedly, LCYb-overexpressing fruits also exhibited a diverse array of ripening phenotypes, including delayed softening and extended shelf life. These phenotypes were accompanied, at the biochemical level, by an increase in abscisic acid (ABA) content, decreased ethylene production, increased density of cell wall material containing linear pectins with a low degree of methylation, and a thicker cuticle with a higher content of cutin monomers and triterpenoids. The levels of several primary metabolites and phenylpropanoid compounds were also altered in the transgenic fruits, which could be attributed to delayed fruit ripening and/or to ABA. Network correlation analysis and pharmacological experiments with the ABA biosynthesis inhibitor, abamine, indicated that altered ABA levels were a direct effect of the increased β-carotene content and were in turn responsible for the extended shelf life phenotype. Thus, manipulation of β-carotene levels results in an improvement not only of the nutritional value of tomato fruits, but also of their shelf life.

Spermidine (Spd) treatment inhibited root cell elongation, promoted deposition of phenolics in cell walls of rhizodermis, xylem elements, and vascular parenchyma, and resulted in a higher number of cells resting in G(1) and G(2) phases in the maize (Zea mays) primary root apex. Furthermore, Spd treatment induced nuclear condensation and DNA fragmentation as well as precocious differentiation and cell death in both early metaxylem and late metaxylem precursors. Treatment with either N-prenylagmatine, a selective inhibitor of polyamine oxidase (PAO) enzyme activity, or N,N(1)-dimethylthiourea, a hydrogen peroxide (H(2)O(2)) scavenger, reverted Spd-induced autofluorescence intensification, DNA fragmentation, inhibition of root cell elongation, as well as reduction of percentage of nuclei in S phase. Transmission electron microscopy showed that N-prenylagmatine inhibited the differentiation of the secondary wall of early and late metaxylem elements, and xylem parenchymal cells. Moreover, although root growth and xylem differentiation in antisense PAO tobacco (Nicotiana tabacum) plants were unaltered, overexpression of maize PAO (S-ZmPAO) as well as down-regulation of the gene encoding S-adenosyl-l-methionine decarboxylase via RNAi in tobacco plants promoted vascular cell differentiation and induced programmed cell death in root cap cells. Furthermore, following Spd treatment in maize and ZmPAO overexpression in tobacco, the in vivo H(2)O(2) production was enhanced in xylem tissues. Overall, our results suggest that, after Spd supply or PAO overexpression, H(2)O(2) derived from polyamine catabolism behaves as a signal for secondary wall deposition and for induction of developmental programmed cell death.

By isolating the process of dislocation emission from a crack tip under an applied tensile stress, we extract from a molecular dynamics simulation the atomic-level displacement and stress fields on the activated slip plane before and after the nucleation event. The stress-displacement relations so obtained provide a direct link with recent continuum descriptions of brittle versus ductile behavior in crack propagation. Crack-tip shielding by the emitted dislocations is demonstrated, as is the role of surface steps in dislocation nucleation and crack-tip blunting.