WorldWideScience

Sample records for mutant lacking chlorophyll

  1. Chlorophyll mutants in Phaseolus vulgaris (L.) Savi

    Svetleva, D.; Petkova, S.

    1991-01-01

    Three-year investigations were conducted on chlorophyll mutants of three type: viridissima, claroviridis, flavoviridis, viridocostata and xanthomarginata produced post gamma irradiation ( 60 Co, 8 krad, 280 rad/min). Cell division rate in spectrum and in quantity of induced aberrations was found to have no significant differences with the control. Chlorophyll mutations compared to the control are less developed and their productive characters are less manifested. Cell division rate and the quantity of induced aberrations have no relation to the elements of productivity in the mutants investigated. 3 tabs., 12 refs

  2. Investigations on gamma ray induced chlorophyll variegated mutants

    Datta, S.K.; Dwivedi, A.K.; Banerji, B.K.

    1995-01-01

    Considering economic importance of chlorophyll variegation in floriculture trade an attempt was made for cytological, anatomical and biochemical analysis of four Bougainvillea and Lantana depressa chlorophyll variegated mutants for better and clear understanding of origin of chlorophyll variegation. No cytological evidence could be detected for their origin. Anatomical and biochemical examinations revealed that chlorophyll variegation in these mutants were due to changes in biosynthesis pathways and time of chlorophyll synthesis in palisade and spongy mesophyll cells. (author). 7 refs., 3 figs., 3 tabs

  3. Genetic analysis of sunflower chlorophyll mutants

    Mashkina, E.V.; Guskov, E.P.

    2001-01-01

    The method of getting the chlorophyll mutations in sunflower was developed by Y.D. Beletskii in 1969 with the use of N-nitroso-N-methylurea (NMH). Certain concentrations of NMH are known to induce plastid mutations in growing seeds, and their yield depends on the duration of the exposure. The given work presented studies on the influence of rifampicin (R) and 2,4-dinitrophenol (DNP) on the genetic activity NMH, as an inductor of plastid and nuclear mutations

  4. Mahalanobis distance screening of Arabidopsis mutants with chlorophyll fluorescence

    Codrea, C. C.; Hakala-Yatkin, M.; Karlund-Marttila, A.; Nedbal, Ladislav; Aittokallio, T.; Nevalainen, O. S.; Tyystjärvi, E.

    2010-01-01

    Roč. 105, č. 3 (2010), s. 273-283 ISSN 0166-8595 Institutional research plan: CEZ:AV0Z60870520 Keywords : arabidopsis thaliana * chlorophyll fluorescence * fluorescence imaging * mutant detection * outlier detection Subject RIV: EH - Ecology, Behaviour Impact factor: 2.410, year: 2010 http://www.springerlink.com/content/x3586512462pn006/

  5. Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

    E.Yu. Garnik

    2015-12-01

    Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

  6. Leaf and canopy photosynthesis of a chlorophyll deficient soybean mutant.

    Sakowska, Karolina; Alberti, Giorgio; Genesio, Lorenzo; Peressotti, Alessandro; Delle Vedove, Gemini; Gianelle, Damiano; Colombo, Roberto; Rodeghiero, Mirco; Panigada, Cinzia; Juszczak, Radosław; Celesti, Marco; Rossini, Micol; Haworth, Matthew; Campbell, Benjamin W; Mevy, Jean-Philippe; Vescovo, Loris; Cendrero-Mateo, M Pilar; Rascher, Uwe; Miglietta, Franco

    2018-03-02

    The photosynthetic, optical, and morphological characteristics of a chlorophyll-deficient (Chl-deficient) "yellow" soybean mutant (MinnGold) were examined in comparison with 2 green varieties (MN0095 and Eiko). Despite the large difference in Chl content, similar leaf photosynthesis rates were maintained in the Chl-deficient mutant by offsetting the reduced absorption of red photons by a small increase in photochemical efficiency and lower non-photochemical quenching. When grown in the field, at full canopy cover, the mutants reflected a significantly larger proportion of incoming shortwave radiation, but the total canopy light absorption was only slightly reduced, most likely due to a deeper penetration of light into the canopy space. As a consequence, canopy-scale gross primary production and ecosystem respiration were comparable between the Chl-deficient mutant and the green variety. However, total biomass production was lower in the mutant, which indicates that processes other than steady state photosynthesis caused a reduction in biomass accumulation over time. Analysis of non-photochemical quenching relaxation and gas exchange in Chl-deficient and green leaves after transitions from high to low light conditions suggested that dynamic photosynthesis might be responsible for the reduced biomass production in the Chl-deficient mutant under field conditions. © 2018 John Wiley & Sons Ltd.

  7. Correlation of electronic carotenoid-chlorophyll interactions and fluorescence quenching with the aggregation of native LHC II and chlorophyll deficient mutants

    Liao, Pen-Nan; Bode, Stefan; Wilk, Laura; Hafi, Nour; Walla, Peter J.

    2010-01-01

    The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid-chlorophyll interactions, φ Coupling Car S 1 -Chl , as measured by comparing chlorophyll fluorescence observed after two- and one-photon excitation, has been investigated using native LHC II samples as well as mutants lacking Chl 2 and Chl 13. For native LHC II the same linear correlation between φ Coupling Car S 1 -Chl and the fluorescence quenching was observed as previously reported for the pH and Zea-dependent quenching of LHC II . In order to elucidate which carotenoid-chlorophyll pair might dominate this correlation we also investigated the mutants lacking Chl 2 and Chl 13. However, also with these mutants the same linear correlation as for native LHC II was observed. This provides indication that these two chlorophylls play only a minor role for the observed effects. Nevertheless, we also conclude that this does not exclude that their neighboured carotenoids, lutein 1 and neoxanthin, might interact electronically with other chlorophylls close by.

  8. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 1. Chlorophyll Mutations in Allelic tw Mutants and Their Revertants

    Vaitkuniene, V.

    1995-01-01

    Genotypical environment is an essential factor determining the mutability of mutants of the same type. Decreased chlorophyll mutant frequency was a common characteristic of all tested tw type (tw, tw 1 , tw 2 ) mutants induced in barley c. 'Auksiniai II'. The mutability of all the tested revertants was close to that of the initial c. 'Auksiniai II'. (author). 9 refs., 2 tabs

  9. Genetic Analysis and Molecular Mapping of a Novel Chlorophyll-Deficit Mutant Gene in Rice

    Xiao-qun HUANG

    2008-03-01

    Full Text Available A rice etiolation mutant 824ys featured with chlorophyll deficiency was identified from a normal green rice variety 824B. It showed whole green-yellow plant from the seedling stage, reduced number of tillers and longer growth duration. The contents of chlorophyll, chlorophyll a, chlorophyll b and net photosynthetic rate in leaves of the mutant obviously decreased, as well as the number of spikelets per panicle, seed setting rate and 1000-grain weight compared with its wild-type parent. Genetic analyses on F1 and F2 generations of 824ys crossed with three normal green varieties showed that the chlorophyll-deficit mutant character was controlled by a pair of recessive nuclear gene. Genetic mapping of the mutant gene was conducted by using microsatellite markers and F2 mapping population of 495R/824ys, and the mutant gene of 824ys was mapped on the short arm of rice chromosome 3. The genetic distances from the target gene to the markers RM218, RM282 and RM6959 were 25.6 cM, 5.2 cM and 21.8 cM, respectively. It was considered to be a new chlorophyll-deficit mutant gene and tentatively named as chl11(t.

  10. Gamma ray induced chlorophyll and morphological mutants in grasspea

    Das, P.K.; Kundagrami, S.

    2000-01-01

    Higher dose of gamma ray treatment such as 30 kR promoted larger chlorophyll as well as morphological mutation frequency and spectrum. In both M 1 and M 2 generation marginata significantly out numbered other types of chlorophyll mutations. On the other hand, along morphological mutations stunted growth types were recovered more frequently. Both the genotypes Nirmal and P-24 differed greatly for their mutagenic specificity. In both M 1 and M 2 generation Nirmal recorded higher chlorophyll and morphological mutation frequency and spectrum indicating differential genotype response to different dosages of gamma ray treatment. (author)

  11. Identical substitutions in magnesium chelatase paralogs result in chlorophyll deficient soybean mutants

    The soybean (Glycine max (L.) Merr.) chlorophyll deficient line MinnGold is a spontaneous mutant characterized by yellow foliage. Map-based cloning and transgenic complementation revealed that the mutant phenotype is caused by a non-synonymous nucleotide substitution in the third exon of a Mg-chelat...

  12. Use of induced chlorophyll deficient mutants to identify 'heterotic blocks' in pearl millet chromosomes

    Burton, G.W.

    1989-01-01

    Full text: Chlorophyll deficient mutant stocks induced in 'Tift 23' of pearl millet (Pennisetum americanum L. Leeke) were crossed with 'Tift 23' and 5 other normal inbreds to study the effect of these deleterious recessive genes on yield. The difference between near-isogenic S 1 (F 2 ) populations homozygous or heterozygous for the chlorophyll deficiency was not significant. However among 69 S 1 progenies from crosses with other inbreds the heterozygotes were higher yielding than the homozygotes in 53 cases, 15 of which were significant. A mutant like 'M5' identified a high yield 'heterotic block' in 'Inbred 104' and a very low yield 'heterotic block' in 'Inbred 186'. (author)

  13. Characterization of a Thermo-Inducible Chlorophyll-Deficient Mutant in Barley

    Rong Wang

    2017-11-01

    Full Text Available Leaf color is an important trait for not only controlling crop yield but also monitoring plant status under temperature stress. In this study, a thermo-inducible chlorophyll-deficient mutant, named V-V-Y, was identified from a gamma-radiated population of the barley variety Vlamingh. The leaves of the mutant were green under normal growing temperature but turned yellowish under high temperature in the glasshouse experiment. The ratio of chlorophyll a and chlorophyll b in the mutant declined much faster in the first 7–9 days under heat treatment. The leaves of V-V-Y turned yellowish but took longer to senesce under heat stress in the field experiment. Genetic analysis indicated that a single nuclear gene controlled the mutant trait. The mutant gene (vvy was mapped to the long arm of chromosome 4H between SNP markers 1_0269 and 1_1531 with a genetic distance of 2.2 cM and a physical interval of 9.85 Mb. A QTL for grain yield was mapped to the same interval and explained 10.4% of the yield variation with a LOD score of 4. This QTL is coincident with the vvy gene interval that is responsible for the thermo-inducible chlorophyll-deficient trait. Fine mapping, based on the barley reference genome sequence, further narrowed the vvy gene to a physical interval of 0.428 Mb with 11 annotated genes. This is the first report of fine mapping a thermo-inducible chlorophyll-deficient gene in barley.

  14. Severity of mutant phenotype in a series of chlorophyll-deficient wheat mutants depends on light intensity and the severity of the block in chlorophyll synthesis.

    Falbel, T G; Meehl, J B; Staehelin, L A

    1996-10-01

    Analyses of a series of allelic chlorina mutants of wheat (Triticum aestivum L.), which have partial blocks in chlorophyll (Chl) synthesis and, therefore, a limited Chl supply, reinforce the principle that Chl is required for the stable accumulation of Chl-binding proteins and that only reaction centers accumulate when the supply of Chl is severely limited. Depending on the rate of Chl accumulation (determined by the severity of the mutation) and on the rate of turnover of Chl and its precursors (determined by the environment in which the plant is grown), the mutants each reach an equilibrium of Chl synthesis and degradation. Together these mutants generate a spectrum of phenotypes. Under the harshest conditions (high illumination), plants with moderate blocks in Chl synthesis have membranes with very little Chl and Chl-proteins and membrane stacks resembling the thylakoids of the lethal xantha mutants of barely grown at low to medium light intensities (which have more severe blocks). In contrast, when grown under low-light conditions the same plants with moderate blocks have thylakoids resembling those of the wild type. The wide range of phenotypes of Chl b-deficient mutants has historically produced more confusion than enlightenment, but incomparable growth conditions can now explain the discrepancies reported in the literature.

  15. Motor hypertonia and lack of locomotor coordination in mutant mice lacking DSCAM.

    Lemieux, Maxime; Laflamme, Olivier D; Thiry, Louise; Boulanger-Piette, Antoine; Frenette, Jérôme; Bretzner, Frédéric

    2016-03-01

    Down syndrome cell adherence molecule (DSCAM) contributes to the normal establishment and maintenance of neural circuits. Whereas there is abundant literature regarding the role of DSCAM in the neural patterning of the mammalian retina, less is known about motor circuits. Recently, DSCAM mutation has been shown to impair bilateral motor coordination during respiration, thus causing death at birth. DSCAM mutants that survive through adulthood display a lack of locomotor endurance and coordination in the rotarod test, thus suggesting that the DSCAM mutation impairs motor control. We investigated the motor and locomotor functions of DSCAM(2J) mutant mice through a combination of anatomical, kinematic, force, and electromyographic recordings. With respect to wild-type mice, DSCAM(2J) mice displayed a longer swing phase with a limb hyperflexion at the expense of a shorter stance phase during locomotion. Furthermore, electromyographic activity in the flexor and extensor muscles was increased and coactivated over 20% of the step cycle over a wide range of walking speeds. In contrast to wild-type mice, which used lateral walk and trot at walking speed, DSCAM(2J) mice used preferentially less coordinated gaits, such as out-of-phase walk and pace. The neuromuscular junction and the contractile properties of muscles, as well as their muscle spindles, were normal, and no signs of motor rigidity or spasticity were observed during passive limb movements. Our study demonstrates that the DSCAM mutation induces dystonic hypertonia and a disruption of locomotor gaits. Copyright © 2016 the American Physiological Society.

  16. Identification of the 7-Hydroxymethyl Chlorophyll a Reductase of the Chlorophyll Cycle in Arabidopsis[W

    Meguro, Miki; Ito, Hisashi; Takabayashi, Atsushi; Tanaka, Ryouichi; Tanaka, Ayumi

    2011-01-01

    The interconversion of chlorophyll a and chlorophyll b, referred to as the chlorophyll cycle, plays a crucial role in the processes of greening, acclimation to light intensity, and senescence. The chlorophyll cycle consists of three reactions: the conversions of chlorophyll a to chlorophyll b by chlorophyllide a oxygenase, chlorophyll b to 7-hydroxymethyl chlorophyll a by chlorophyll b reductase, and 7-hydroxymethyl chlorophyll a to chlorophyll a by 7-hydroxymethyl chlorophyll a reductase. We identified 7-hydroxymethyl chlorophyll a reductase, which is the last remaining unidentified enzyme of the chlorophyll cycle, from Arabidopsis thaliana by genetic and biochemical methods. Recombinant 7-hydroxymethyl chlorophyll a reductase converted 7-hydroxymethyl chlorophyll a to chlorophyll a using ferredoxin. Both sequence and biochemical analyses showed that 7-hydroxymethyl chlorophyll a reductase contains flavin adenine dinucleotide and an iron-sulfur center. In addition, a phylogenetic analysis elucidated the evolution of 7-hydroxymethyl chlorophyll a reductase from divinyl chlorophyllide vinyl reductase. A mutant lacking 7-hydroxymethyl chlorophyll a reductase was found to accumulate 7-hydroxymethyl chlorophyll a and pheophorbide a. Furthermore, this accumulation of pheophorbide a in the mutant was rescued by the inactivation of the chlorophyll b reductase gene. The downregulation of pheophorbide a oxygenase activity is discussed in relation to 7-hydroxymethyl chlorophyll a accumulation. PMID:21934147

  17. Lack of seasonality in phytoplankton standing stock (chlorophyll a) and production in the western Bay of Bengal

    Madhu, N.V.; Jyothibabu, R.; Maheswaran, P.A.; Gerson, V.J.; Gopalakrishnan, T.C.; Nair, K.K.C.

    The investigations in the western Bay of Bengal (BoB) during summer, winter and spring intermonsoon periods evidenced lack of pronounced seasonal variation in phytoplankton standing stock (chlorophyll a) and primary production. The supply...

  18. A temperature-sensitive winter wheat chlorophyll mutant derived from space mutagenesis

    Zhao Hongbin; Guo Huijun; Zhao Linshu; Gu Jiayu; Zhao Shirong; Li Junhui; Liu Luxiang

    2010-01-01

    A temperature-sensitive winter wheat (Triticum aestivum L.) chlorophyll mutant Mt18, induced by spaceflight mutagenesis, was studied on agronomic traits, ultrastructure of chloroplast and photosynthesis characteristics. The leaf color of the mutant Mt18 showed changes from green to albino and back to green during the whole growth period. Plant height, productive tillers, spike length, grains and grain weight per plant, and 1000-grain weight of the mutant were lower than those of the wild type. The ultrastructural observation showed that no significant difference was found between the mutant and the wild type during prior albino stage, however, at the albino stage the number of granum-thylakoids and grana lamellae became fewer or completely disappeared, but the strom-thylakoid was obviously visible. After turning green,the structure of most chloroplasts recovered to normal, but number of chloroplast was still lower than that of the wild type. When exposed to photosynthetic active radiation (PAR) of 110 μmol·m -2 ·s -1 , the non-photochemical quenching (NPQ) of mutant was significantly lower than that of the wild type, and the non-regulated energy dissipation (Y NO ) was significantly higher than that of the wild type, while the change of the maximum photosystem II quantum yield (F v /F m ), potential activity of photosystem II (F v /F o ), photochemical quenching (q P ), effective quantum yield (Y PSI I) and regulated non-photochemical energy dissipation (Y NPQ ) were different at various stages. In addition, the differences of the electron transport rate (ETR), photochemical quenching (q P ), and effective quantum yield (Y PSI I) between mutant and wild type varied under different PAR conditions. It was concluded that with the change of chloroplast ultrastructure, the leaf color and photosynthesis of the wheat mutant Mt18 change correspondingly. The chloroplast ultrastructure was obviously different from that of wild type, and the photosynthetic efficiency

  19. Enhanced photoprotection by protein-bound vs free xanthophyll pools: a comparative analysis of chlorophyll b and xanthophyll biosynthesis mutants.

    Dall'Osto, Luca; Cazzaniga, Stefano; Havaux, Michel; Bassi, Roberto

    2010-05-01

    When light absorbed by plants exceeds the capacity of photosynthesis, the xanthophyll violaxanthin is reversibly de-epoxidized to zeaxanthin in the so-called xanthophyll cycle. Zeaxanthin plays a key role in the protection of photosynthetic organisms against excess light, by promoting rapidly reversible (qE) and long-term (qI) quenching of excited chlorophylls, and preventing lipid oxidation. The photoprotective role of zeaxanthin, either free or bound to light-harvesting complexes (Lhcs), has been investigated by using mutants lacking Chl b (ch1) and/or specific xanthophyll species (npq, lut2). The ch1 mutation causes (1) the absence of Lhcb proteins; (2) strong reduction of the feedback de-excitation (qE); and (3) accumulation of xanthophylls as free pigments into thylakoids. Ch1 mutants showed extreme sensitivity to photo-oxidative stress in high light, due to higher singlet oxygen (¹O₂) release. The double mutant ch1npq1 was more sensitive to photo-oxidation than ch1, showing that zeaxanthin does protect lipids even when free in the membrane. Nevertheless, lack of zeaxanthin had a much stronger impact on the level of lipid peroxidation in Lhcs-containing plants (WT vs npq1) with respect to Lhc-less plants (ch1 vs ch1npq1), implying that its protective effect is enhanced by interaction with antenna proteins. It is proposed that the antioxidant capacity of zeaxanthin is empowered in the presence of PSII-LHCs-Zea complexes, while its effect on enhancement of qE only provides a minor contribution. Comparison of the sensitivity of WT vs npq1 plants to exogenous ¹O₂ suggests that besides the scavenging of ¹O₂, at least one additional mechanism is involved in chloroplast photoprotection.

  20. Identification and genetic assay of a high-chlorophyll-content mutant in Rice

    Liu Baofu; Chen Xifeng; Jin Yang; Gu Zhimin; Ma Bojun; Zhu Xudong

    2011-01-01

    A deep rice mutant ZM1120 was screened from the γ-rays irradiation mutation library of Zhonghua 11. Compared to the wild-type control, this mutant were darker (greener) in shoots and leaves, and after sowing 60 and 90 d, the content of chlorophyll were increased by 16.0% and 7.2%, respectively, and the content of carotenoid also increased by 23.1% and 24.2%, respectively. After sowing 90 d the net photosynthetic rate and transpiration rate were increased by 16.3% and 11.4%, respectively. The agronomical traits of this mutant significantly changed, and the traits of plant height, flag-leaf length, flag-leaf width, tiller number per plant, panicle length and setting rate decreased, but the grain length and 1000-grain weight increased by 7.9% and 2.6%. Genetic analysis revealed that the mutation phenotype was controlled by a single recessive nuclear gene, and further cloning and function assay will be useful for understanding the mechanism of photosynthesis and for rice breeding in future. (authors)

  1. A preliminary study on induction and identification of chlorophyll mutants of indica type temperature sensitive genie male-sterile rice

    Xia Yingwu; Liu Guifu; Shu Qingyao; Jiang Ronghua; Xie Jiahua

    1995-01-01

    Chlorophyll mutants of different type were obtained from indica type temperature sensitive genie male-sterile rice (cv. 2177s) by using 60 Co γ-rays irradiation. The total chlorophyll mutation frequency reached to 0.26% in M 2 generation. However only about 4.50% of these mutants could survived. Among them, 33 heritable chlorophyll mutant lines were easily distinguished, and were screened and studied. The mutants either showed chlorosis or yellowing or expressed only at seedling period or persisted all growth cycle. The expression of mutant character was stable under different environment. It is suggested that they are useful as the marker traits in two-line hybrid rice. Moreover, the agronomic traits of most of these lines changed in different levels compared with the parent line 2177S. Every mutation line seemed to be controlled by one recessive gene as the F 1 plants of reciprocal crosses between mutant and 2177S showed normal leaf color. And the ratio of green plants/mutant plants was 3:1 in the segregated F 2 population

  2. Photosynthesis, chlorophyll fluorescence, light-harvesting system and photoinhibition resistance of a zeaxanthin-accumulating mutant of Arabidopsis thaliana.

    Tardy, F; Havaux, M

    1996-06-01

    The abscisic-acid-deficient aba-1 mutant of Arabidopsis thaliana is unable to epoxidize zeaxanthin. As a consequence, it contains large amounts of this carotenoid and lacks epoxy-xanthophylls. HPLC analysis of pigment contents in leaves, isolated thylakoids and preparations of the major light-harvesting complex of photosystem II (PSII) (LHC-II) indicated that zeaxanthin replaced neoxanthin, violaxanthin and antheraxanthin in the light-harvesting system of PSII in aba-1. Non-denaturing electrophoretic fractionation of solubilized thylakoids showed that the xanthophyll imbalance in aba-1 was associated with a pronounced decrease in trimeric LHC-II in favour of monomeric complexes, with a substantial increase in free pigments (mainly zeaxanthin and chlorophyll b), suggesting a decreased stability of LHC-II. The reduced thermostability of PSII in aba-1 was also deduced from in vivo chlorophyll fluorescence measurements. Wild-type and aba-1 leaves could not be distinguished on the basis of their photosynthetic performance: no significant difference was observed between the two types of leaves for light-limited and light-saturated photosynthetic oxygen evolution, PSII photochemistry and PSII to PSI electron flow. When dark-adapted leaves (grown in white light of 80 mumol m-2s-1) were suddenly exposed to red light of 150 mumol m-2s-1, there was a strong nonphotochemical quenching of chlorophyll fluorescence, the amplitude of which was virtually identical (at steady state) in aba-1 and wild-type leaves, despite the fact that the xanthophyll cycle pigment pool was completely in the form of zeaxanthin in aba-1 and almost exclusively in the form of violaxanthin in the wild type. A high concentration of zeaxanthin in aba-1 thylakoids did not, in itself, provide any particular protection against the photoinhibition of PSII. Taken together, the presented results indicate the following: (1) zeaxanthin can replace epoxy-xanthophylls in LHC-II without significantly affecting the

  3. Effect of postirradiation storage of seeds on the structural chromosomal mutations in chlorophyll mutants of sunflower (Helianthus annuus L)

    Sizova, L.I.

    1976-01-01

    The paper comprises the results of the investigation of the storage effect in irradiated seeds on the frequency and the spectrum of structural mutations of chromosomes in normal green plants and in spontaneous chlorophyll mutants of sunflower. The seeds of chlorophyll mutants lutescens and xantha and those of green plants stored for 3 years have been 60 Co gamma-irradiated with doses of 0.5; 1.0; 2.0; 3.0; 5.0 and 10 kr. After the irradiation the seeds have been stored for a year under conventional laboratory conditions. As a result of the post-irradiation storage of seeds for a year the decrease in the proportion of aberrant cells by 3 to 6% at the expense of cells with paired fragments has been observed in green plants. In chlorophyll mutants the storage of seeds after the irradiation results in the 9 to 37% increase of the proportion of aberrant cells at the expense of cells with single and paired bridges and with paired fragments. This gives evidence in favour of the assumption that in spontaneous chlorophyll mutants the processes of the post-irradiation recovery either fail altogether, or proceed at a very low level

  4. Genetic cytological and biochemical study of a tomato chlorophyll mutant of the xanthic type, obtained by irradiation of the seeds

    Lefort, M.; Duranton, J.; Galmiche, J.M.; Roux, E.

    1958-01-01

    Irradiation of Lycopersicum aesculantum seeds with increasing doses of X-rays and thermal neutrons leads to the appearance of chlorophyll mutations in the descendants of the irradiated seeds. A genetic study of one of these mutants of the xanthic type showed that it was a recessive mutant with typical mono-genetic separation, while the cytological study demonstrated that the differentiation of the plast stopped at the stage of elementary lamella. Finally it is shown that in the light, the mutation brings about a very large deviation of the carbon metabolism towards the synthesis of amino acids and proteins, at the expense of that of glucosides. (author) [fr

  5. The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants.

    Tyutereva, Elena V; Evkaikina, Anastasiia I; Ivanova, Alexandra N; Voitsekhovskaja, Olga V

    2017-09-01

    The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.

  6. Characterization of a bacteriophage T4 mutant lacking DNA-dependent ATPase

    Behme, M.T.; Ebisuzaki, K.

    1975-01-01

    A DNA-dependent ATPase has previously been purified from bacteriophage T4-infected Escherichia coli. A mutant phage strain lacking this enzyme has been isolated and characterized. Although the mutant strain produced no detectable DNA-dependent ATPase, growth properties were not affected. Burst sizes were similar for the mutant phage and T4D in polAl, recB, recC, uvrA, uvrB, uvrC, and various DNA-negative E. coli. UV sensitivity and genetic recombination were normal in a variety of E. coli hosts. Mapping data indicate that the genetic locus controlling the mutant occurs near gene 56. The nonessential nature of this gene is discussed

  7. Mutant Mice Lacking the p53 C-Terminal Domain Model Telomere Syndromes

    Simeonova, I.; Jaber, S.; Draskovic, I.; Bardot, B.; Fang, M.; Bouarich-Bourimi, R.; Lejour, V.; Charbonnier, L.; Soudais, C.; Bourdon, J.C.; Huerre, M.; Londono-Vallejo, A.; Toledo, F.

    2013-01-01

    Mutations in p53, although frequent in human cancers, have not been implicated in telomere-related syndromes. Here, we show that homozygous mutant mice expressing p53(Delta31), a p53 lacking the C-terminal domain, exhibit increased p53 activity and suffer from aplastic anemia and pulmonary fibrosis,

  8. Inhibition of cell division in hupA hupB mutant bacteria lacking HU protein.

    Dri, A M; Rouviere-Yaniv, J; Moreau, P L

    1991-01-01

    Escherichia coli hupA hypB double mutants that lack HU protein have severe cellular defects in cell division, DNA folding, and DNA partitioning. Here we show that the sfiA11 mutation, which alters the SfiA cell division inhibitor, reduces filamentation and production of anucleate cells in AB1157 hupA hupB strains. However, lexA3(Ind-) and sfiB(ftsZ)114 mutations, which normally counteract the effect of the SfiA inhibitor, could not restore a normal morphology to hupA hupB mutant bacteria. The...

  9. Photosynthesis, light use efficiency, and yield of reduced-chlorophyll soybean mutants in field conditions

    Reducing chlorophyll (chl) content may improve the conversion efficiency of absorbed radiation into biomass (ec) and therefore yield in dense monoculture crops by improving light penetration and distribution within the canopy. Modeling suggests that reducing chl content may also reduce leaf temperat...

  10. Inhibition of cell division in hupA hupB mutant bacteria lacking HU protein.

    Dri, A M; Rouviere-Yaniv, J; Moreau, P L

    1991-01-01

    Escherichia coli hupA hypB double mutants that lack HU protein have severe cellular defects in cell division, DNA folding, and DNA partitioning. Here we show that the sfiA11 mutation, which alters the SfiA cell division inhibitor, reduces filamentation and production of anucleate cells in AB1157 hupA hupB strains. However, lexA3(Ind-) and sfiB(ftsZ)114 mutations, which normally counteract the effect of the SfiA inhibitor, could not restore a normal morphology to hupA hupB mutant bacteria. The LexA repressor, which controls the expression of the sfiA gene, was present in hupA hupB mutant bacteria in concentrations half of those of the parent bacteria, but this decrease was independent of the specific cleavage of the LexA repressor by activated RecA protein. One possibility to account for the filamentous morphology of hupA hupB mutant bacteria is that the lack of HU protein alters the expression of specific genes, such as lexA and fts cell division genes. Images PMID:2019558

  11. Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities

    Thompson, J.; Chassy, B.M.; Egan, W.

    1985-04-01

    A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose- phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of (/sup 14/C)lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution /sup 31/P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM.

  12. Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities

    Thompson, J.; Chassy, B.M.; Egan, W.

    1985-01-01

    A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose- phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of [ 14 C]lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution 31 P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM

  13. Characterization of a chlorophyll b-less mutant of Lemna gibba G3

    Slovin, J.P.

    1987-01-01

    Nitrosomethylurea mutagenesis of whole plants of duckweed, Lemna gibba G3, produced many plants with various types of obvious pigment abnormalities. One such plant is yellow-green and has a chlorophyll a/b ratio of 8. Spectra from plants grown in white light show a prominent absorption peak at 472 nm, that is not present in spectra from wild type plants. This peak is present, however, when wild type plants are grown under red light conditions. B-less plants accumulate some chlorophyll b under some light conditions and depending on the age of the plants. SDS-PAGE of proteins in thylakoid membranes and in a soluble fraction show that the only obvious band missing corresponds to the LHCP. Preliminary data from 35 S methionine in vivo labeling indicate that there is some LHCP being synthesized in these plant, however the identity of the labeled bands is only now being established using antibodies, and the amount of labeled material does not appear to be the same as in the wild type. The author is currently doing the genetics on this variant and are interested in determining whether the b-less phenotype results from a mutation involving synthesis of the LHCP

  14. In response to partial plant shading, the lack of phytochrome A does not directly induce leaf senescence but alters the fine-tuning of chlorophyll biosynthesis

    Brouwer, Bastiaan; Gardeström, Per; Keech, Olivier

    2014-01-01

    Phytochrome is thought to control the induction of leaf senescence directly, however, the signalling and molecular mechanisms remain unclear. In the present study, an ecophysiological approach was used to establish a functional connection between phytochrome signalling and the physiological processes underlying the induction of leaf senescence in response to shade. With shade it is important to distinguish between complete and partial shading, during which either the whole or only a part of the plant is shaded, respectively. It is first shown here that, while PHYB is required to maintain chlorophyll content in a completely shaded plant, only PHYA is involved in maintaining the leaf chlorophyll content in response to partial plant shading. Second, it is shown that leaf yellowing associated with strong partial shading in phyA-mutant plants actually correlates to a decreased biosynthesis of chlorophyll rather than to an increase of its degradation. Third, it is shown that the physiological impact of this decreased biosynthesis of chlorophyll in strongly shaded phyA-mutant leaves is accompanied by a decreased capacity to adjust the Light Compensation Point. However, the increased leaf yellowing in phyA-mutant plants is not accompanied by an increase of senescence-specific molecular markers, which argues against a direct role of PHYA in inducing leaf senescence in response to partial shade. In conclusion, it is proposed that PHYA, but not PHYB, is essential for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. In turn, this mechanism allows the shaded leaf to adjust its photosynthetic machinery to very low irradiances, thus maintaining a positive carbon balance and repressing the induction of leaf senescence, which can occur under prolonged periods of shade. PMID:24604733

  15. Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

    Roncaglia Enrica

    2011-04-01

    Full Text Available Abstract Background Reactive oxygen species (ROS are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2 accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are

  16. Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

    2011-01-01

    Background Reactive oxygen species (ROS) are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2) accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are discussed. PMID:21481232

  17. Evidence for dynamic network regulation of Drosophila photoreceptor function from mutants lacking the neurotransmitter histamine

    An eDau

    2016-03-01

    Full Text Available Synaptic feedback from interneurons to photoreceptors can help to optimize visual information flow by balancing its allocation on retinal pathways under changing light conditions. But little is known about how this critical network operation is regulated dynamically. Here, we investigate this question by comparing signaling properties and performance of wild-type Drosophila R1-R6 photoreceptors to those of the hdcJK910 mutant, which lacks the neurotransmitter histamine and therefore cannot transmit information to interneurons. Recordings show that hdcJK910 photoreceptors sample similar amounts of information from naturalistic stimulation to wild-type photoreceptors, but this information is packaged in smaller responses, especially under bright illumination. Analyses reveal how these altered dynamics primarily resulted from network overload that affected hdcJK910 photoreceptors in two ways. First, the missing inhibitory histamine input to interneurons almost certainly depolarized them irrevocably, which in turn increased their excitatory feedback to hdcJK910 R1-R6s. This tonic excitation depolarized the photoreceptors to artificially high potentials, reducing their operational range. Second, rescuing histamine input to interneurons in hdcJK910 mutant also restored their normal phasic feedback modulation to R1-R6s, causing photoreceptor output to accentuate dynamic intensity differences at bright illumination, similar to the wild-type. These results provide mechanistic explanations of how synaptic feedback connections optimize information packaging in photoreceptor output and novel insight into the operation and design of dynamic network regulation of sensory neurons.

  18. The diageotropica mutant of tomato lacks high specific activity auxin sites

    Hicks, G.R.; Lomax, T.L.; Rayle, D.L.

    1989-01-01

    Tomato (Lycopersicum esculentum, Mill) plants homozygous for the single gene diageotropica (dgt) mutation have reduced shoot growth, abnormal vascular tissue, altered leaf morphology, and lack of lateral root branching. These and other morphological and physiological abnormalities suggest that dgt plants are unable to respond to the plant growth hormone auxin (indole-3-acetic acid, IAA). The photoaffinity auxin analogue 3 H-5N 3 -IAA specifically labels a polypeptide doublet of 40 ad 42 kD in membrane preparations from stems of the parental variety VFN8, but not from stems of dgt. In elongation tests, excised dgt roots respond in the same manner to IAA an VFN8 roots. These data suggest that the two polypeptides are part of a physiologically important auxin receptor system which is altered in a tissue-specific manner in the mutant

  19. Mutant Mice Lacking the p53 C-Terminal Domain Model Telomere Syndromes

    Iva Simeonova

    2013-06-01

    Full Text Available Mutations in p53, although frequent in human cancers, have not been implicated in telomere-related syndromes. Here, we show that homozygous mutant mice expressing p53Δ31, a p53 lacking the C-terminal domain, exhibit increased p53 activity and suffer from aplastic anemia and pulmonary fibrosis, hallmarks of syndromes caused by short telomeres. Indeed, p53Δ31/Δ31 mice had short telomeres and other phenotypic traits associated with the telomere disease dyskeratosis congenita and its severe variant the Hoyeraal-Hreidarsson syndrome. Heterozygous p53+/Δ31 mice were only mildly affected, but decreased levels of Mdm4, a negative regulator of p53, led to a dramatic aggravation of their symptoms. Importantly, several genes involved in telomere metabolism were downregulated in p53Δ31/Δ31 cells, including Dyskerin, Rtel1, and Tinf2, which are mutated in dyskeratosis congenita, and Terf1, which is implicated in aplastic anemia. Together, these data reveal that a truncating mutation can activate p53 and that p53 plays a major role in the regulation of telomere metabolism.

  20. Cadmium toxicity to Microcystis aeruginosa PCC 7806 and its microcystin-lacking mutant.

    Bin Huang

    Full Text Available The adverse effects of microcystin (MC produced by cyanobacteria have drawn considerable attention from the public. Yet it remains unclear whether MC confers any benefits to the cyanobacteria themselves. One suggested function of MC is complexation, which may influence the bioaccumulation and toxicity of trace metals. To test this hypothesis, we examined Cd toxicity to wild-type Microcystis aeruginosa PCC 7806 (WT and its MC-lacking mutant (MT under nutrient-enriched (+NP, phosphorus-limited (-P, and nitrogen-limited (-N conditions. The accumulation of Cd and the biochemical parameters associated with its detoxification [total phosphorus (TP, inorganic polyphosphate (Poly-P, and glutathione (GSH in the cells as well as intra- and extra-cellular carbohydrates] were quantified. Although the -P cyanobacteria accumulated less Cd than their +NP and -N counterparts, the different nutrient-conditioned cyanobacteria were similarly inhibited by similar free ion concentration of Cd in the medium ([Cd2+]F. Such good toxicity predictability of [Cd2+]F was ascribed to the synchronous decrease in the intracellular concentrations of Cd and TP. Nevertheless, Cd toxicity was still determined by the intracellular Cd to phosphorus ratio (Cd/P, in accordance with what has been reported in the literature. On the other hand, the concentrations of TP, Poly-P, and carbohydrates went up, but GSH concentration dropped down with the enhancement of [Cd2+]F, indicating their association with Cd detoxification. Although the inactivation of MC peptide synthetase gene had some nutrient and Cd concentration dependent effects on the parameters above, both cyanobacterial strains showed the same Cd accumulation ability and displayed similar Cd sensitivity. These results suggest that MC cannot affect metal toxicity either by regulating metal accumulation or by altering the detoxification ability of the cyanobacteria. Other possible functions of MC need to be further investigated.

  1. Lack of chemically induced mutation in repair-deficient mutants of yeast

    Prakash, L.

    1974-01-01

    Two genes, rad6 and rad9, that confer radiation sensitivity in the yeast Saccharomyces cerevisiae also greatly reduce the frequency of chemically-induced reversions of a tester mutant cyc1-131, which is a chain initiation mutant in the structural gene determining iso-1-cytochrome c. Mutations induced by ethyl methanesulfonate (EMS), diethyl sulfate (DES), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), nitroquinoline oxide (NQO), nitrosoguanidine (NTG), nitrogen mustard (HN2), β-propiolactone, and tritiated uridine, as well as mutations induced by ultraviolet light (UV) and ionizing radiation were greatly diminished in strains homozygous for either the rad6 or rad9 gene. Nitrous acid and nitrosoimidazolidone (NIL), on the other hand, were highly mutagenic in these repair-deficient mutants, and at low doses, these mutagens acted with about the same efficiency as in the normal RAD strain. At high doses of either nitrous acid or NIL, however, reversion frequencies were significantly reduced in the two rad mutants compared to normal strains. Although both rad mutants are immutable to about the same extent, the rad9 strains tend to be less sensitive to the lethal effect of chemical mutagens than rad6 strains. It is concluded that yeast requires a functional repair system for mutation induction by chemical agents. (auth)

  2. Lack of chemically induced mutation in repair-deficient mutants of yeast.

    Prakash, L

    1974-12-01

    Two genes, rad6 and rad9, that confer radiation sensitivity in the yeast Saccharomyces cerevisiae also greatly reduce the frequency of chemically-induced reversions of a tester mutant cyc1-131, which is a chain initiation mutant in the structural gene determining iso-1-cytochrome c. Mutations induced by ethyl methanesulfonate (EMS), diethyl sulfate (DES), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), nitroquinoline oxide (NQO), nitrosoguanidine (NTG), nitrogen mustard (HN2), beta-propiolactone, and tritiated uridine, as well as mutations induced by ultraviolet light (UV) and ionizing radiation were greatly diminished in strains homozygous for either the rad6 or rad9 gene. Nitrous acid and nitrosoimidazolidone (NIL), on the other hand, were highly mutagenic in these repair-deficient mutants, and at low doses, these mutagens acted with about the same efficiency as in the normal RAD strain. At high doses of either nitrous acid or NIL, however, reversion frequencies were significantly reduced in the two rad mutants compared to normal strains. Although both rad mutants are immutable to about the same extent, the rad9 strains tend to be less sensitive to the lethal effect of chemical mutagens than rad6 strains. It is concluded that yeast requires a functional repair system for mutation induction by chemical agents.

  3. Arabidopsis mutants lacking asparaginases develop normally but exhibit enhanced root inhibition by exogenous asparagine.

    Ivanov, Ana; Kameka, Alexander; Pajak, Agnieszka; Bruneau, Luanne; Beyaert, Ronald; Hernández-Sebastià, Cinta; Marsolais, Frédéric

    2012-06-01

    Asparaginase catalyzes the degradation of L-asparagine to L-aspartic acid and ammonia, and is implicated in the catabolism of transported asparagine in sink tissues of higher plants. The Arabidopsis genome includes two genes, ASPGA1 and ASPGB1, belonging to distinct asparaginase subfamilies. Conditions of severe nitrogen limitation resulted in a slight decrease in seed size in wild-type Arabidopsis. However, this response was not observed in a homozygous T-DNA insertion mutant where ASPG genes had been inactivated. Under nitrogen-sufficient conditions, the ASPG mutant had elevated levels of free asparagine in mature seed. This phenotype was observed exclusively under conditions of low illumination, when a low ratio of carbon to nitrogen was translocated to the seed. Mutants deficient in one or both asparaginases were more sensitive than wild-type to inhibition of primary root elongation and root hair emergence by L-asparagine as a single nitrogen source. This enhanced inhibition was associated with increased accumulation of asparagine in the root of the double aspga1-1/-b1-1 mutant. This indicates that inhibition of root growth is likely elicited by asparagine itself or an asparagine-derived metabolite, other than the products of asparaginase, aspartic acid or ammonia. During germination, a fusion between the ASPGA1 promoter and beta-glucuronidase was expressed in endosperm cells starting at the micropylar end. Expression was initially high throughout the root and hypocotyl, but became restricted to the root tip after three days, which may indicate a transition to nitrogen-heterotrophic growth.

  4. Arabidopsis mutants lacking phenolic sunscreens exhibit enhanced ultraviolet-B injury and oxidative damage

    Landry, L.G.; Last, R.L.; Chapple, C.C.S.

    1995-01-01

    We have assessed ultraviolet-B (UV-B)-induced injury in wild-type Arabidopsis thaliana and two mutants with altered aromatic secondary product biosynthesis. Arabidopsis mutants defective in the ability to synthesize UV-B-absorbing compounds (flavonoids in transparent testa 5 [tt5] and sinapate esters in ferulic acid hydroxylase 1 [fah 1]) are more sensitive to UV-B than is the wild-type Landsberg erecta. Despite its ability to accumulate UV-absorptive flavonoid compounds, the ferulic acid hydroxylase mutant fah1 exhibits more physiological injury (growth inhibition and foliar lesions) than either wild type or tt5. The extreme UV-B sensitivity of fah1 demonstrates the importance of hydroxycinnamate esters as UV-B protectants. Consistent with the whole-plant response, the highest levels of lipid and protein oxidation products were seen in fah1. Ascorbate peroxidase enzyme activity was also increased in the leaves of UV-B-treated plants in a dose- and genotype-dependent manner. These results demonstrate that, in A. thaliana, hydryoxycinnamates are more effective UV-B protectants than flavonoids. The data also indicate that A. thaliana responds to UV-B as an oxidative stress, and sunscreen compounds reduce the oxidative damage caused by UV-B. 36 refs., 6 figs

  5. Rett Syndrome Mutant Neural Cells Lacks MeCP2 Immunoreactive Bands.

    Carlos Bueno

    Full Text Available Dysfunctions of MeCP2 protein lead to various neurological disorders such as Rett syndrome and Autism. The exact functions of MeCP2 protein is still far from clear. At a molecular level, there exist contradictory data. MeCP2 protein is considered a single immunoreactive band around 75 kDa by western-blot analysis but several reports have revealed the existence of multiple MeCP2 immunoreactive bands above and below the level where MeCP2 is expected. MeCP2 immunoreactive bands have been interpreted in different ways. Some researchers suggest that multiple MeCP2 immunoreactive bands are unidentified proteins that cross-react with the MeCP2 antibody or degradation product of MeCP2, while others suggest that MeCP2 post-transcriptional processing generates multiple molecular forms linked to cell signaling, but so far they have not been properly analyzed in relation to Rett syndrome experimental models. The purpose of this study is to advance understanding of multiple MeCP2 immunoreactive bands in control neural cells and p.T158M MeCP2e1 mutant cells. We have generated stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Application of N- and C- terminal MeCP2 antibodies, and also, RFP antibody minimized concerns about nonspecific cross-reactivity, since they react with the same antigen at different epitopes. We report the existence of multiple MeCP2 immunoreactive bands in control cells, stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Also, MeCP2 immunoreactive bands differences were found between wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Slower migration phosphorylated band around 70kDa disappeared in p.T158M MeCP2e1-RFP mutant expressing cells. These data suggest that threonine 158 could represent an important phosphorylation site potentially involved in protein function. Our results clearly indicate that MeCP2 antibodies have no cross-reactivity with similar epitopes on others proteins, supporting the

  6. Physiological and fermentation properties of Bacillus coagulans and a mutant lacking fermentative lactate dehydrogenase activity.

    Su, Yue; Rhee, Mun Su; Ingram, Lonnie O; Shanmugam, K T

    2011-03-01

    Bacillus coagulans, a sporogenic lactic acid bacterium, grows optimally at 50-55 °C and produces lactic acid as the primary fermentation product from both hexoses and pentoses. The amount of fungal cellulases required for simultaneous saccharification and fermentation (SSF) at 55 °C was previously reported to be three to four times lower than for SSF at the optimum growth temperature for Saccharomyces cerevisiae of 35 °C. An ethanologenic B. coagulans is expected to lower the cellulase loading and production cost of cellulosic ethanol due to SSF at 55 °C. As a first step towards developing B. coagulans as an ethanologenic microbial biocatalyst, activity of the primary fermentation enzyme L-lactate dehydrogenase was removed by mutation (strain Suy27). Strain Suy27 produced ethanol as the main fermentation product from glucose during growth at pH 7.0 (0.33 g ethanol per g glucose fermented). Pyruvate dehydrogenase (PDH) and alcohol dehydrogenase (ADH) acting in series contributed to about 55% of the ethanol produced by this mutant while pyruvate formate lyase and ADH were responsible for the remainder. Due to the absence of PDH activity in B. coagulans during fermentative growth at pH 5.0, the l-ldh mutant failed to grow anaerobically at pH 5.0. Strain Suy27-13, a derivative of the l-ldh mutant strain Suy27, that produced PDH activity during anaerobic growth at pH 5.0 grew at this pH and also produced ethanol as the fermentation product (0.39 g per g glucose). These results show that construction of an ethanologenic B. coagulans requires optimal expression of PDH activity in addition to the removal of the LDH activity to support growth and ethanol production.

  7. Genetic cytological and biochemical study of a tomato chlorophyll mutant of the xanthic type, obtained by irradiation of the seeds; Etude genetique, cytologique et biochimique d'un mutant chlorophyllien de tomate du type xantha, obtenu par irradiation de graines

    Lefort, M; Duranton, J; Galmiche, J M; Roux, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Irradiation of Lycopersicum aesculantum seeds with increasing doses of X-rays and thermal neutrons leads to the appearance of chlorophyll mutations in the descendants of the irradiated seeds. A genetic study of one of these mutants of the xanthic type showed that it was a recessive mutant with typical mono-genetic separation, while the cytological study demonstrated that the differentiation of the plast stopped at the stage of elementary lamella. Finally it is shown that in the light, the mutation brings about a very large deviation of the carbon metabolism towards the synthesis of amino acids and proteins, at the expense of that of glucosides. (author) [French] L'irradiation de graines de Lycopersicum Aesculantum avec des doses croissantes de rayons X et de neutrons thermiques entraine l'apparition de mutations chlorophylliennes dans la descendance des graines irradiees. L'etude genetique d'un de ces mutants du type xantha a montre qu'il s'agissait d'un mutant recessif a disjonction monogenique typique, tandis que l'etude cytologique a revele que la differentiation du plaste s'arretait au stade de lamelles elementaires. Il est apparu enfin qu'a la lumiere la mutation entrainait une deviation tres importante du metabolisme du carbone vers la synthese des acides amines et des proteines, au detriment de celle des glucides. (auteur)

  8. Characterisation of the Aspergillus nidulans frA1 mutant: hexose phosphorylation and apparent lack of involvement of hexokinase in glucose repression.

    Ruijter, G.J.G.; Panneman, H.; Broeck, van den H.C.; Bennett, J.M.; Visser, J.

    1996-01-01

    Hexose phosphorylation was studied in Aspergillus nidulans wild-type and in a fructose non-utilising mutant (frA). The data indicate the presence of at least one hexokinase and one glucokinase in wild-type A. nidulans, while the frA1 mutant lacks hexokinase activity. The A. nidulans gene encoding

  9. Possible role of the 38 kDa protein, lacking in the gastrula-arrested Xenopus mutant, in gastrulation.

    Tanaka, Tetsuya S; Ikenishi, Kohji

    2002-02-01

    An acidic, 38 kDa protein that is present in Xenopus wild-type embryos has been previously shown to be lacking in gastrula-arrested mutant embryos. To gain understanding of the role of this protein, its spatio-temporal distribution and involvement in gastrulation was investigated using the monoclonal antibody (9D10) against it. The protein was prominent in the cortical cytoplasm of cells facing the outside in the animal hemisphere of embryos until the gastrula stage, and in ciliated epithelial cells of embryos at stages later than the late neurula. When the 9D10 antibody was injected into fertilized wild-type eggs, they cleaved normally, but most of them had arrested development, always at the early stage of gastrulation, as in the mutant embryos. In contrast, the majority of the control antibody-injected eggs gastrulated normally and developed further. Cytoskeletal F-actin, which was mainly observed in the area beneath the plasma membrane facing the outside of the epithelial layer of not only the dorsal involuting marginal zone but also the dorsal, vegetal cell mass of the control antibody-injected embryos at the early gastrula stage, was scarcely recognized in the corresponding area of the 9D10 antibody-injected embryos. It is likely that the paucity of the F-actin caused by the 9D10 antibody inhibition of the 38 kDa protein might lead to a failure of cell movement in gastrulation, resulting in developmental arrest.

  10. Management of chimera and in vitro mutagenesis for development of new flower color/shape and chlorophyll variegated mutants in chrysanthemum

    Datta, S.K. [CSIR, Madhyamgram Experimental Farm, Bose Institute, Kolkata (India)], E-mail: subodhskdatta@rediffmail.com; Chakrabarty, D [Floriculture Laboratory, National Botanical Research Institute, Lucknow (India)

    2008-07-01

    Induced mutagenesis has played a major role in the development of many new flower color/shape mutant varieties in ornamentals. The main bottleneck with vegetatively propagated plants is that the mutation appears as a chimera whether developed through bud sport or through induced mutation. The size of the mutant sector varies from a narrow streak on a petal to the entire flower and from a portion of a branch to the entire branch. When a portion of a branch or entire branch is mutated, the mutant tissue can be isolated; on the other hand, a small sector of a mutated branch or flower cannot be isolated using the available conventional propagation techniques. A novel technique has been standardized in our laboratory for the management of chimeric tissues through direct shoot regeneration from chrysanthemum florets. 'Kasturba Gandhi', a large white flowered chrysanthemum, developed few chimeric yellow florets due to spontaneous mutation. Using in vitro protocol new yellow florets were established in pure form. In vitro mutagenesis experiments were conducted treating ray florets of chrysanthemum cultivars using gamma rays. Induced chimeric yellow, white, light yellow, light mauve and dark mauve floret color sectors and chlorophyll variegation in leaves of cv. 'Maghi' (with mauve floret and green leaves) have been established in pure form. Gamma ray induced sectorial yellow florets of cv. 'Lilith' (white floret) and yellow ray florets in both the cvs. 'Purnima' (with white florets) and 'Colchi Bahar' (with red florets) have been isolated in pure form through in vitro management. Induced sectorial flower color/shape mutations in cvs. 'Puja', 'Lalima', 'Flirt', 'Maghi' and 'Sunil' have been isolated in pure form through in vitro culture. Gamma radiation procedure and tissue culture techniques have been optimized to regenerate plants from stem internodes, stem node, shoot tip and ray florets. Present technique has opened a new way for isolating new flower color

  11. Expression and characterization of recombinant human factor V and a mutant lacking a major portion of the connecting region

    Kane, W.H.; Devore-Carter, D.; Ortel, T.L.

    1990-01-01

    Human coagulation factor V is a protein cofactor that is an essential component of the prothrombinase complex. A full-length factor V cDNA has been subcloned into the mammalian expression vector pDX and used to transfect COS cells. Approximately 95 ± 4% of the recombinant human factor V (rHFV) synthesized in COS cells is secreted into the culture medium. Factor V activity determined by fibrometer assay increased approximately 5-fold from 0.027 ± 0.012 to 0.124 ± 0.044 unit/mL following activation by the factor V activating enzyme from Russell's viper venom (RVV-V). A chromogenic assay specific for factor Va indicated that recombinant factor V had 3.8 ± 1.3% of the activity of the activated protein. The estimated specific activity of the recombinant factor Va was approximately 1,800 ± 500 units/mg, which is similar to the specific activity of purified plasma factor Va of 1,700-2,000 units/mg. Immunoprecipitation of [ 35 S]methionine-labeled rHFV revealed a single high molecular mass component. Treatment of rHFV with thrombin or RVV-V resulted in the formation of proteolytic products that were similar to those seen with plasma factor V. The authors have also expressed a mutant, rHFV-des-B 811-1441 , that lacks a large portion of the highly glycosylated connecting region that is present in factor V. This mutant constitutively expressed 38 ± 7% of the activity of the RVV-V-activated protein. These results suggest that one of the functions of the large connecting region in factor V is to inhibit constitutive procoagulant activity

  12. The Arabidopsis thiamin-deficient mutant pale green1 lacks thiamin monophosphate phosphatase of the vitamin B1 biosynthesis pathway.

    Hsieh, Wei-Yu; Liao, Jo-Chien; Wang, Hsin-Tzu; Hung, Tzu-Huan; Tseng, Ching-Chih; Chung, Tsui-Yun; Hsieh, Ming-Hsiun

    2017-07-01

    Thiamin diphosphate (TPP, vitamin B 1 ) is an essential coenzyme present in all organisms. Animals obtain TPP from their diets, but plants synthesize TPPde novo. We isolated and characterized an Arabidopsis pale green1 (pale1) mutant that contained higher concentrations of thiamin monophosphate (TMP) and less thiamin and TPP than the wild type. Supplementation with thiamin, but not the thiazole and pyrimidine precursors, rescued the mutant phenotype, indicating that the pale1 mutant is a thiamin-deficient mutant. Map-based cloning and whole-genome sequencing revealed that the pale1 mutant has a mutation in At5g32470 encoding a TMP phosphatase of the TPP biosynthesis pathway. We further confirmed that the mutation of At5g32470 is responsible for the mutant phenotypes by complementing the pale1 mutant with constructs overexpressing full-length At5g32470. Most plant TPP biosynthetic enzymes are located in the chloroplasts and cytosol, but At5g32470-GFP localized to the mitochondrion of the root, hypocotyl, mesophyll and guard cells of the 35S:At5g32470-GFP complemented plants. The subcellular localization of a functional TMP phosphatase suggests that the complete vitamin B1 biosynthesis pathway may involve the chloroplasts, mitochondria and cytosol in plants. Analysis of PALE1 promoter-uidA activity revealed that PALE1 is mainly expressed in vascular tissues of Arabidopsis seedlings. Quantitative RT-PCR analysis of TPP biosynthesis genes and genes encoding the TPP-dependent enzymes pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase revealed that the transcript levels of these genes were upregulated in the pale1 mutant. These results suggest that endogenous levels of TPP may affect the expression of genes involved in TPP biosynthesis and TPP-dependent enzymes. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  13. A Sordaria macrospora mutant lacking the leu1 gene shows a developmental arrest during fruiting body formation.

    Kück, Ulrich

    2005-10-01

    Developmental mutants with defects in fruiting body formation are excellent resources for the identification of genetic components that control cellular differentiation processes in filamentous fungi. The mutant pro4 of the ascomycete Sordaria macrospora is characterized by a developmental arrest during the sexual life cycle. This mutant generates only pre-fruiting bodies (protoperithecia), and is unable to form ascospores. Besides being sterile, pro4 is auxotrophic for leucine. Ascospore analysis revealed that the two phenotypes are genetically linked. After isolation of the wild-type leu1 gene from S. macrospora, complementation experiments demonstrated that the gene was able to restore both prototrophy and fertility in pro4. To investigate the control of leu1 expression, other genes involved in leucine biosynthesis specifically and in the general control of amino acid biosynthesis ("cross-pathway control") have been analysed using Northern hybridization and quantitative RT-PCR. These analyses demonstrated that genes of leucine biosynthesis are transcribed at higher levels under conditions of amino acid starvation. In addition, the expression data for the cpc1 and cpc2 genes indicate that cross-pathway control is superimposed on leucine-specific regulation of fruiting body development in the leu1 mutant. This was further substantiated by growth experiments in which the wild-type strain was found to show a sterile phenotype when grown on a medium containing the amino acid analogue 5-methyl-tryptophan. Taken together, these data show that pro4 represents a novel mutant type in S. macrospora, in which amino acid starvation acts as a signal that interrupts the development of the fruiting body.

  14. Transcriptomic and proteomic approach to identify differentially expressed genes and proteins in Arabidopsis thaliana mutants lacking chloroplastic 1 and cytosolic FBPases reveals several levels of metabolic regulation.

    Soto-Suárez, Mauricio; Serrato, Antonio J; Rojas-González, José A; Bautista, Rocío; Sahrawy, Mariam

    2016-12-01

    During the photosynthesis, two isoforms of the fructose-1,6-bisphosphatase (FBPase), the chloroplastidial (cFBP1) and the cytosolic (cyFBP), catalyse the first irreversible step during the conversion of triose phosphates (TP) to starch or sucrose, respectively. Deficiency in cyFBP and cFBP1 isoforms provokes an imbalance of the starch/sucrose ratio, causing a dramatic effect on plant development when the plastidial enzyme is lacking. We study the correlation between the transcriptome and proteome profile in rosettes and roots when cFBP1 or cyFBP genes are disrupted in Arabidopsis thaliana knock-out mutants. By using a 70-mer oligonucleotide microarray representing the genome of Arabidopsis we were able to identify 1067 and 1243 genes whose expressions are altered in the rosettes and roots of the cfbp1 mutant respectively; whilst in rosettes and roots of cyfbp mutant 1068 and 1079 genes are being up- or down-regulated respectively. Quantitative real-time PCR validated 100% of a set of 14 selected genes differentially expressed according to our microarray analysis. Two-dimensional (2-D) gel electrophoresis-based proteomic analysis revealed quantitative differences in 36 and 26 proteins regulated in rosettes and roots of cfbp1, respectively, whereas the 18 and 48 others were regulated in rosettes and roots of cyfbp mutant, respectively. The genes differentially expressed and the proteins more or less abundant revealed changes in protein metabolism, RNA regulation, cell signalling and organization, carbon metabolism, redox regulation, and transport together with biotic and abiotic stress. Notably, a significant set (25%) of the proteins identified were also found to be regulated at a transcriptional level. This transcriptomic and proteomic analysis is the first comprehensive and comparative study of the gene/protein re-adjustment that occurs in photosynthetic and non-photosynthetic organs of Arabidopsis mutants lacking FBPase isoforms.

  15. Photosystem II repair and plant immunity: Lessons learned from Arabidopsis mutant lacking the THYLAKOID LUMEN PROTEIN 18.3

    Sari eJärvi

    2016-03-01

    Full Text Available Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425. Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.

  16. The Arabidopsis nox mutant lacking carotene hydroxylase activity reveals a critical role for xanthophylls in photosystem I biogenesis.

    Dall'Osto, Luca; Piques, Maria; Ronzani, Michela; Molesini, Barbara; Alboresi, Alessandro; Cazzaniga, Stefano; Bassi, Roberto

    2013-02-01

    Carotenes, and their oxygenated derivatives xanthophylls, are essential components of the photosynthetic apparatus. They contribute to the assembly of photosynthetic complexes and participate in light absorption and chloroplast photoprotection. Here, we studied the role of xanthophylls, as distinct from that of carotenes, by characterizing a no xanthophylls (nox) mutant of Arabidopsis thaliana, which was obtained by combining mutations targeting the four carotenoid hydroxylase genes. nox plants retained α- and β-carotenes but were devoid in xanthophylls. The phenotype included depletion of light-harvesting complex (LHC) subunits and impairment of nonphotochemical quenching, two effects consistent with the location of xanthophylls in photosystem II antenna, but also a decreased efficiency of photosynthetic electron transfer, photosensitivity, and lethality in soil. Biochemical analysis revealed that the nox mutant was specifically depleted in photosystem I function due to a severe deficiency in PsaA/B subunits. While the stationary level of psaA/B transcripts showed no major differences between genotypes, the stability of newly synthesized PsaA/B proteins was decreased and translation of psaA/B mRNA was impaired in nox with respect to wild-type plants. We conclude that xanthophylls, besides their role in photoprotection and LHC assembly, are also needed for photosystem I core translation and stability, thus making these compounds indispensable for autotrophic growth.

  17. Lifespan decrease in a Caenorhabditis elegans mutant lacking TRX-1, a thioredoxin expressed in ASJ sensory neurons.

    Miranda-Vizuete, Antonio; Fierro González, Juan Carlos; Gahmon, Gabriele; Burghoorn, Jan; Navas, Plácido; Swoboda, Peter

    2006-01-23

    Thioredoxins are a class of small proteins that play a key role in regulating many cellular redox processes. We report here the characterization of the first member of the thioredoxin family in metazoans that is mainly associated with neurons. The Caenorhabditis elegans gene B0228.5 encodes a thioredoxin (TRX-1) that is expressed in ASJ ciliated sensory neurons, and to some extent also in the posterior-most intestinal cells. TRX-1 is active at reducing protein disulfides in the presence of a heterologous thioredoxin reductase. A mutant worm strain carrying a null allele of the trx-1 gene displays a reproducible decrease in both mean and maximum lifespan when compared to wild-type. The identification and characterization of TRX-1 paves the way to use C. elegans as an in vivo model to study the role of thioredoxins in lifespan and nervous system physiology and pathology.

  18. An attenuated Shigella mutant lacking the RNA-binding protein Hfq provides cross-protection against Shigella strains of broad serotype.

    Mitobe, Jiro; Sinha, Ritam; Mitra, Soma; Nag, Dhrubajyoti; Saito, Noriko; Shimuta, Ken; Koizumi, Nobuo; Koley, Hemanta

    2017-07-01

    Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin.

  19. Gamma-ray induction of a mutant soybean [Glycine max (L.) Merrill] line lacking all seed lipoxygenases

    Hajika, Makita; Suda, Ikuo; Sakai, Shinji; Takahashi, Masakazu

    1997-01-01

    Induction of a soybean line lacking all isozymes of seed lipoxygenase was attempted using γ-radiation and of 1,813 seeds in M 3 generation, only one was identified as a seed lacking all the isozymes by SDS-PAGE. This line did not present any physiological abnormality over 10 generations or more (M 4 -M 14 ) and no significant influence of the enzyme on the agricultural traits was observed during the performance test in fields. In the resistance test against insect pests, significant differences were not found among the varieties and the lines tested. These results suggest that deletion of all lipoxygenase isozymes would not affect the soybean production in practice. The lipoxygenase activity was not detected in the leaves as well as the seeds of this line, suggesting that this enzyme are not indispensable for the soybean growth. The validity of this line in food processing fields was examined through determining the levels of hexanal production and DETBA. This line was found able to improve the taste of soybean cookies and use in combination with other materials as flour, egg, etc. because the line has no lipoxygenase activity. (M.N.)

  20. Alterations in gene expression in mutant amyloid precursor protein transgenic mice lacking Niemann-Pick type C1 protein.

    Mahua Maulik

    Full Text Available Niemann-Pick type C (NPC disease, a rare autosomal recessive disorder caused mostly by mutation in NPC1 gene, is pathologically characterized by the accumulation of free cholesterol in brain and other tissues. This is accompanied by gliosis and loss of neurons in selected brain regions, including the cerebellum. Recent studies have shown that NPC disease exhibits intriguing parallels with Alzheimer's disease, including the presence of neurofibrillary tangles and increased levels of amyloid precursor protein (APP-derived β-amyloid (Aβ peptides in vulnerable brain neurons. To evaluate the role of Aβ in NPC disease, we determined the gene expression profile in selected brain regions of our recently developed bigenic ANPC mice, generated by crossing APP transgenic (Tg mice with heterozygous Npc1-deficient mice. The ANPC mice exhibited exacerbated neuronal and glial pathology compared to other genotypes [i.e., APP-Tg, double heterozygous (Dhet, Npc1-null and wild-type mice]. Analysis of expression profiles of 86 selected genes using real-time RT-PCR arrays showed a wide-spectrum of alterations in the four genotypes compared to wild-type controls. The changes observed in APP-Tg and Dhet mice are limited to only few genes involved mostly in the regulation of cholesterol metabolism, whereas Npc1-null and ANPC mice showed alterations in the expression profiles of a number of genes regulating cholesterol homeostasis, APP metabolism, vesicular trafficking and cell death mechanism in both hippocampus and cerebellum compared to wild-type mice. Intriguingly, ANPC and Npc1-null mice, with some exceptions, exhibited similar changes, although more genes were differentially expressed in the affected cerebellum than the relatively spared hippocampus. The altered gene profiles were found to match with the corresponding protein levels. These results suggest that lack of Npc1 protein can alter the expression profile of selected transcripts as well as proteins, and

  1. An attenuated Shigella mutant lacking the RNA-binding protein Hfq provides cross-protection against Shigella strains of broad serotype.

    Jiro Mitobe

    2017-07-01

    Full Text Available Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin.

  2. Phytoplankton chlorophyll

    van de Poll, W.H.; Kulk, G.; Timmermans, K.R.; Brussaard, C.P.D.; van der Woerd, H.J.; Kehoe, M.J.; Mojica, K.D.A.; Visser, R.J.W.; Rozema, P.D.; Buma, A.G.J.

    2013-01-01

    Relationships between sea surface temperature (SST, > 10 m) and vertical density stratification, nutrient concentrations, and phytoplankton biomass, composition, and chlorophyll a (Chl a) specific absorption were assessed in spring and summer from latitudes 29 to 63 degrees N in the northeast

  3. The use of heterozygote soybean chlorophyll-deficient mutant gene Y11 as a test-system for environmental monitoring after the Chernobyl accident

    Rashidov, N.; Grodzinski, D.

    1994-01-01

    A heterozygote soybean line contains a gene of chlorophyll-deficiency, y 11 gene. The gene Y 11 is only partially dominant over y 11 ; thus heterozygote Y 11 y 11 plant has leaves of light green colour. Mitotic crossing-over and somatic mosaicism on Y 11 y 11 leaves of heterozygote plants are observed by scheme Y 11 Y 11 - Y 11 y 11 - y 11 y 11 as double and/or single spots. Investigation has been carried out to evaluate the low level radioactivity effects on heterozygote soybean as test-system. Solution of 3 H 2 O and 90 SrCl 2 has been used as a beta-source. The seeds were soaked in 3 H 2 O (0.2 MBq/ml) for 96 h or in 90 SrCl 2 water solution (10 MBq/ml) during 3 days. The effects of beta-irradiation were compared with the data from experiments with acute gamma-irradiation. The dose used ranged from 1 to 30 Gy (dose rate 0.14 Gy/c). Some experimental plots were also selected in Kiev, Zaporozhe regions and in the 10-km zone around Chernobyl. In the field experiments the lowest frequency of somatic mutation was registered in Kiev and Zaporozhe region where the environmental conditions were comparatively clear. But for the low accumulated doses in the 10-km zone around Chernobyl and in the laboratory experiments with beta-irradiation (for 3 H and 90 Sr), the genetic effects were high enough. It is necessary to take into account that for acute gamma-irradiation a nearly linear relationship between the dose and frequency of the somatic mutation was estimated. This fact allows to determine RBE for environmental pollution with various radioactive isotopes. It is proposed to use the heterozygote soybean as a sensitive test-system for studying the genetic effects in radioactive contaminated areas of Chernobyl region. (author)

  4. Effect of NaN3 on oxygen-dependent lethality of UV-A in Escherichia coli mutants lacking active oxygen-defence and DNA-repair systems

    Yamada, Kazumasa; Ono, Tetsuyoshi; Nishioka, Hajime

    1996-01-01

    Escherichia coli mutants which lack defence systems against such active oxygen forms as OxyR (ΔoxyR), superoxide dismutase (SOD) (sodA and sodB) and catalase (katE and katG) are sensitive to UV-A lethality under aerobic conditions, whereas OxyR- and SOD-mutants have resistance under anaerobic conditions and in the presence of sodium azide (NaN 3 ) during irradiation. UV-A induces lipid peroxidation in the ΔoxyR mutant, which is suppressed by NaN 3 . These results suggest that UV-A generates 1 O 2 or the hydroxyl radical to produce lipid peroxides intracellularly in the ΔoxyR mutant and that O 2 - stress may be generated in the sodAB mutant after 8 hr of exposure to UV-A. The sensitivities of such DNA repair-deficient mutants as recA ind- and uvrA to UV-A also were examined and compared. These mutants are sensitive to UV-A lethality under aerobic conditions but show only slight resistance under anaerobic conditions or in the presence of NaN 3 during irradiation. We conclude that NaN 3 protects these mutant cells from oxygen-dependent UV-A lethality. (author)

  5. Lack of negative charge in the E46Q mutant of photoactive yellow protein prevents partial unfolding of the blue shifted intermediate

    Derix, N.M.; Wechselberger, R.W.|info:eu-repo/dai/nl/304829005; van der Horst, M.A.; Hellingwerf, K.J.; Boelens, R.|info:eu-repo/dai/nl/070151407; Kaptein, R.|info:eu-repo/dai/nl/074334603; van Nuland, N.A.J.

    2003-01-01

    The long-lived light-induced intermediate (pB) of the E46Q mutant (glutamic acid is replaced by glutamine at position 46) of photoactive yellow protein (PYP) has been investigated by NMR spectroscopy. The ground state of this mutant is very similar to that of wild-type PYP (WT), whereas the pB

  6. Induction of chlorophyll chimeras and chlorophyll mutations in mungbean (Vigna radiata) cv. T44

    Singh, V.P.; Yadav, R.D.S.

    1993-01-01

    Uniform and healthy seeds of mungbean (Vigna radiata) cv. T44 were exposed to varying doses of gamma rays, ethyl methane sulphonate (EMS) and combination treatment of gamma rays with EMS. The data were recorded for seed germination, plant survival, frequency and spectrum of chlorophyll chimeras in M 1 and chlorophyll mutations in M 2 generation. Among all, the combination treatments were found most effective for inducing chlorophyll chimeras and chlorophyll mutations than the gamma rays or EMS alone. Of the mutants under reference, the albino, xantha and chlorina showed monogenic recessive while viridis exhibited digenic recessive inheritance. (author). 8 refs., 2 tabs

  7. Indicators: Chlorophyll a

    Chlorophyll allows plants (including algae) to photosynthesize, i.e., use sunlight to convert simple molecules into organic compounds. Chlorophyll a is the predominant type of chlorophyll found in green plants and algae.

  8. Variations of L- and D-amino acid levels in the brain of wild-type and mutant mice lacking D-amino acid oxidase activity.

    Du, Siqi; Wang, Yadi; Weatherly, Choyce A; Holden, Kylie; Armstrong, Daniel W

    2018-05-01

    D-amino acids are now recognized to be widely present in organisms and play essential roles in biological processes. Some D-amino acids are metabolized by D-amino acid oxidase (DAO), while D-Asp and D-Glu are metabolized by D-aspartate oxidase (DDO). In this study, levels of 22 amino acids and the enantiomeric compositions of the 19 chiral proteogenic entities have been determined in the whole brain of wild-type ddY mice (ddY/DAO +/+ ), mutant mice lacking DAO activity (ddY/DAO -/- ), and the heterozygous mice (ddY/DAO +/- ) using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). No significant differences were observed for L-amino acid levels among the three strains except for L-Trp which was markedly elevated in the DAO +/- and DAO -/- mice. The question arises as to whether this is an unknown effect of DAO inactivity. The three highest levels of L-amino acids were L-Glu, L-Asp, and L-Gln in all the three strains. The lowest L-amino acid level was L-Cys in ddY/DAO +/- and ddY/DAO -/- mice, while L-Trp showed the lowest level in ddY/DAO +/+ mice. The highest concentration of D-amino acid was found to be D-Ser, which also had the highest % D value (~ 25%). D-Glu had the lowest % D value (~ 0.01%) in all the three strains. Significant differences of D-Leu, D-Ala, D-Ser, D-Arg, and D-Ile were observed in ddY/DAO +/- and ddY/DAO -/- mice compared to ddY/DAO +/+ mice. This work provides the most complete baseline analysis of L- and D-amino acids in the brains of ddY/DAO +/+ , ddY/DAO +/- , and ddY/DAO -/- mice yet reported. It also provides the most effective and efficient analytical approach for measuring these analytes in biological samples. This study provides fundamental information on the role of DAO in the brain and may be relevant for future development involving novel drugs for DAO regulation.

  9. Generation and characterization of pigment mutants of ...

    Compared to the wild CC-124, these mutants are characterized by a decrease in chlorophyll a & b content and an increase in carotenoids. The lowest decrease in chlorophyll a was 3 to 4 folds, while the highest increase in carotenoids was 2 to 4 folds. The result of bio-test, using the resulting pigment mutant of C. reinhardtii ...

  10. Production of the bioactive compounds violacein and indolmycin is conditional in a maeA mutant of Pseudoalteromonas luteoviolacea S4054 lacking the malic enzyme

    Mariane S. Thøgersen

    2016-09-01

    Full Text Available It has previously been reported that some strains of the marine bacterium Pseudoalteromonas luteoviolacea produce the purple bioactive pigment violacein as well as the antibiotic compound indolmycin, hitherto only found in Streptomyces. The purpose of the present study was to determine the relative role of each of these two compounds as antibacterial compounds in P. luteoviolacea S4054. Using Tn10 transposon mutagenesis, a mutant strain that was significantly reduced in violacein production in mannose-containing substrates was created. Full genome analyses revealed that the vio-biosynthetic gene cluster was not interrupted by the transposon; instead the insertion was located to the maeA gene encoding the malic enzyme. Supernatant of the mutant strain inhibited Vibrio anguillarum and Staphylococcus aureus in well diffusion assays and in MIC assays at the same level or even more pronounced as the wild type strain. The mutant strain killed V. anguillarum in co-culture experiments as efficiently as the wild type. Using UHPLC-UV/Vis analyses, we quantified violacein and indolmycin, and the mutant strain only produced 7-10% the amount of violacein compared to the wildtype strain. In contrast, the amount of indolmycin produced by the mutant strain was about 300% that of the wildtype. Since inhibition of V. anguillarum and S. aureus by the mutant strain was similar to that of the wild type, it is concluded that violacein is not the major antibacterial compound in P. luteoviolacea. We furthermore propose that production of violacein and indolmycin may be metabolically linked and that yet unidentified antibacterial compound(s may be play a role in the antibacterial activity of P. luteoviolacea.

  11. The spontaneous chlorophyll mutation frequency in barley

    Jørgensen, Jørgen Helms; Jensen, Hans Peter

    1986-01-01

    A total of 1866 barley plants were progeny tested in the greenhouse. Twenty-five plants segregated for newly arisen, spontaneous chlorophyll mutant genes. Among the total of 470,129 seedlings screened there were 79 mutants (1.7 .+-. 0.6 .times. 10-4). The data are added to data from three similar...... materials and the resulting estimate of the chlorophyll mutant frequency is 1.6 .times. 10-4 in about 1.43 million seedlings. The estimate of the chlorophyll mutation rate per generation is close to 67.3 .times. 10-4 per diploid genome or in the order of 6 .times. 10-7 per locus and haploid genome....

  12. Restoration of growth by manganese in a mutant strain of Escherichia coli lacking most known iron and manganese uptake systems

    Taudte, Nadine; German, Nadezhda; Zhu, Yong-Guan

    2016-01-01

    The interplay of manganese and iron homeostasis and oxidative stress in Escherichia coli can give important insights into survival of bacteria in the phagosome and under differing iron or manganese bioavailabilities. Here, we characterized a mutant strain devoid of all know iron/manganese-uptake ......The interplay of manganese and iron homeostasis and oxidative stress in Escherichia coli can give important insights into survival of bacteria in the phagosome and under differing iron or manganese bioavailabilities. Here, we characterized a mutant strain devoid of all know iron...

  13. Serine:glyoxylate aminotransferase mutant of barley

    Blackwell, R.; Murray, A.; Joy, K.; Lea, P.

    1987-01-01

    A photorespiratory mutant of barley (LaPr 85/84), deficient in both of the major peaks of serine:glyoxylate aminotransferase activity detected in the wild type, also lacks serine:pyruvate and asparagine:glyoxylate aminotransferase activities. Genetic analysis of the mutation demonstrated that these three activities are all carried on the same enzyme. The mutant, when placed in air, accumulated a large pool of serine, showed the expected rate (50%) of ammonia release during photorespiration but produced CO 2 at twice the wild type rate when it was fed [ 14 C] glyoxylate. Compared with the wild type, LaPr 85/84 exhibited abnormal transient changes in chlorophyll a fluorescence when the CO 2 concentration of the air was altered, indicating that the rates of the fluorescence quenching mechanisms were affected in vivo by the lack of this enzyme

  14. The inability of Bacillus licheniformis perR mutant to grow is mainly due to the lack of PerR-mediated fur repression.

    Kim, Jung-Hoon; Yang, Yoon-Mo; Ji, Chang-Jun; Ryu, Su-Hyun; Won, Young-Bin; Ju, Shin-Yeong; Kwon, Yumi; Lee, Yeh-Eun; Youn, Hwan; Lee, Jin-Won

    2017-06-01

    PerR, a member of Fur family protein, is a metal-dependent H 2 O 2 sensing transcription factor that regulates genes involved in peroxide stress response. Industrially important bacterium Bacillus licheniformis contains three PerR-like proteins (PerR BL , PerR2, and PerR3) compared to its close relative Bacillus subtilis. Interestingly, unlike other bacteria including B. subtilis, no authentic perR BL null mutant could be established for B. licheniformis. Thus, we constructed a conditional perR BL mutant using a xylose-inducible promoter, and investigated the genes under the control of PerR BL . PerR BL regulon genes include katA, mrgA, ahpC, pfeT, hemA, fur, and perR as observed for PerR BS . However, there is some variation in the expression levels of fur and hemA genes between B. subtilis and B. licheniformis in the derepressed state. Furthermore, katA, mrgA, and ahpC are strongly induced, whereas the others are only weakly or not induced by H 2 O 2 treatment. In contrast to the B. subtilis perR null mutant which frequently gives rise to large colony phenotype mainly due to the loss of katA, the suppressors of B. licheniformis perR mutant, which can form colonies on LB agar, were all catalase-positive. Instead, many of the suppressors showed increased levels of siderophore production, suggesting that the suppressor mutation is linked to the fur gene. Consistent with this, perR fur double mutant could grow on LB agar without Fe supplementation, whereas perR katA double mutant could only grow on LB agar with Fe supplementation. Taken together, our data suggest that in B. licheniformis, despite the similarity in PerR BL and PerR BS regulon genes, perR is an essential gene required for growth and that the inability of perR null mutant to grow is mainly due to elevated expression of Fur.

  15. The transcriptional response of Lactobacillus sanfranciscensis DSM 20451T and its tcyB mutant lacking a functional cystine transporter to diamide stress.

    Stetina, Mandy; Behr, Jürgen; Vogel, Rudi F

    2014-07-01

    As a result of its strong adaptation to wheat and rye sourdoughs, Lactobacillus sanfranciscensis has the smallest genome within the genus Lactobacillus. The concomitant absence of some important antioxidative enzymes and the inability to synthesize glutathione suggest a role of cystine transport in maintenance of an intracellular thiol balance. Diamide [synonym 1,1'-azobis(N,N-dimethylformamide)] disturbs intracellular and membrane thiol levels in oxidizing protein thiols depending on its initial concentration. In this study, RNA sequencing was used to reveal the transcriptional response of L. sanfranciscensis DSM 20451(T) (wild type [WT]) and its ΔtcyB mutant with a nonfunctional cystine transporter after thiol stress caused by diamide. Along with the different expression of genes involved in amino acid starvation, pyrimidine synthesis, and energy production, our results show that thiol stress in the wild type can be compensated through activation of diverse chaperones and proteases whereas the ΔtcyB mutant shifts its metabolism in the direction of survival. Only a small set of genes are significantly differentially expressed between the wild type and the mutant. In the WT, mainly genes which are associated with a heat shock response are upregulated whereas glutamine import and synthesis genes are downregulated. In the ΔtcyB mutant, the whole opp operon was more highly expressed, as well as a protein which probably includes enzymes for methionine transport. The two proteins encoded by spxA and nrdH, which are involved in direct or indirect oxidative stress responses, are also upregulated in the mutant. This work emphasizes that even in the absence of definitive antioxidative enzymes, bacteria with a small genome and a high frequency of gene inactivation and elimination use small molecules such as the cysteine/cystine couple to overcome potential cell damage resulting from oxidative stress. Copyright © 2014, American Society for Microbiology. All Rights

  16. The Arabidopsis nox Mutant Lacking Carotene Hydroxylase Activity Reveals a Critical Role for Xanthophylls in Photosystem I Biogenesis[C][W

    Dall’Osto, Luca; Piques, Maria; Ronzani, Michela; Molesini, Barbara; Alboresi, Alessandro; Cazzaniga, Stefano; Bassi, Roberto

    2013-01-01

    Carotenes, and their oxygenated derivatives xanthophylls, are essential components of the photosynthetic apparatus. They contribute to the assembly of photosynthetic complexes and participate in light absorption and chloroplast photoprotection. Here, we studied the role of xanthophylls, as distinct from that of carotenes, by characterizing a no xanthophylls (nox) mutant of Arabidopsis thaliana, which was obtained by combining mutations targeting the four carotenoid hydroxylase genes. nox plants retained α- and β-carotenes but were devoid in xanthophylls. The phenotype included depletion of light-harvesting complex (LHC) subunits and impairment of nonphotochemical quenching, two effects consistent with the location of xanthophylls in photosystem II antenna, but also a decreased efficiency of photosynthetic electron transfer, photosensitivity, and lethality in soil. Biochemical analysis revealed that the nox mutant was specifically depleted in photosystem I function due to a severe deficiency in PsaA/B subunits. While the stationary level of psaA/B transcripts showed no major differences between genotypes, the stability of newly synthesized PsaA/B proteins was decreased and translation of psaA/B mRNA was impaired in nox with respect to wild-type plants. We conclude that xanthophylls, besides their role in photoprotection and LHC assembly, are also needed for photosystem I core translation and stability, thus making these compounds indispensable for autotrophic growth. PMID:23396829

  17. Chlorophyll: The wonder pigment

    Bhat, S.R.

    Chlorophyll, the green plant pigment, a 'real life force' of living beings, besides synthesizing food, is a great source of vitamins, minerals and other phytochemicals. Adding chlorophyll rich food to our diet fortifies our body against health...

  18. Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis[OPEN

    2016-01-01

    Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence. Unlike pheophytinase, CLD1 is predominantly expressed in green organs and can dephytylate chlorophyll in vitro. The specific activity is significantly higher for the mutant protein encoded by cld1-1 than the wild-type enzyme, consistent with the semidominant nature of the cld1-1 mutation. Supraoptimal CLD1 activities in cld1-1 mutants and transgenic seedlings led to the proportional accumulation of chlorophyllides derived from chlorophyll dephytylation after heat shock, which resulted in light-dependent cotyledon bleaching. Reducing CLD1 expression diminished thermotolerance and the photochemical efficiency of photosystem II under prolonged moderate heat stress. Taken together, our results suggest that CLD1 is the long-sought enzyme for removing the phytol chain from chlorophyll during its turnover at steady state within the chloroplast. PMID:27920339

  19. Identification of a Chlorophyll Dephytylase Involved in Chlorophyll Turnover in Arabidopsis.

    Lin, Yao-Pin; Wu, Meng-Chen; Charng, Yee-Yung

    2016-12-01

    Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence. Unlike pheophytinase, CLD1 is predominantly expressed in green organs and can dephytylate chlorophyll in vitro. The specific activity is significantly higher for the mutant protein encoded by cld1-1 than the wild-type enzyme, consistent with the semidominant nature of the cld1-1 mutation. Supraoptimal CLD1 activities in cld1-1 mutants and transgenic seedlings led to the proportional accumulation of chlorophyllides derived from chlorophyll dephytylation after heat shock, which resulted in light-dependent cotyledon bleaching. Reducing CLD1 expression diminished thermotolerance and the photochemical efficiency of photosystem II under prolonged moderate heat stress. Taken together, our results suggest that CLD1 is the long-sought enzyme for removing the phytol chain from chlorophyll during its turnover at steady state within the chloroplast. © 2016 American Society of Plant Biologists. All rights reserved.

  20. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 2. Comparison of Various Mutants

    Balchiuniene, L.

    1995-01-01

    Spontaneous and gamma-induced mutability was compared in two groups of genetically unstable barley ear structure mutants - tweaky spike (tw) and branched ear (be). Instability in different loci causes different levels of spontaneous and gamma-induced mutability. A high spontaneous level of chlorophyll mutations is peculiar to be-ust mutants. It is suggested that the high level of induced chlorophyll mutations in allelic tw mutants is a result of better surviving of chlorophyll mutation carriers in the genotypical-physiological environment created by mutant tw alleles. (author). 6 refs., 2 tabs

  1. Mice lacking Ras-GRF1 show contextual fear conditioning but not spatial memory impairments: convergent evidence from two independently generated mouse mutant lines

    Raffaele ed'Isa

    2011-12-01

    Full Text Available Ras-GRF1 is a neuronal specific guanine exchange factor that, once activated by both ionotropic and metabotropic neurotransmitter receptors, can stimulate Ras proteins, leading to long-term phosphorylation of downstream signaling. The two available reports on the behavior of two independently generated Ras-GRF1 deficient mouse lines provide contrasting evidence on the role of Ras-GRF1 in spatial memory and contextual fear conditioning. These discrepancies may be due to the distinct alterations introduced in the mouse genome by gene targeting in the two lines that could differentially affect expression of nearby genes located in the imprinted region containing the Ras-grf1 locus. In order to determine the real contribution of Ras-GRF1 to spatial memory we compared in Morris Water Maze learning the Brambilla’s mice with a third mouse line (GENA53 in which a nonsense mutation was introduced in the Ras-GRF1 coding region without additional changes in the genome and we found that memory in this task is normal. Also, we measured both contextual and cued fear conditioning, which were previously reported to be affected in the Brambilla’s mice, and we confirmed that contextual learning but not cued conditioning is impaired in both mouse lines. In addition, we also tested both lines for the first time in conditioned place aversion in the Intellicage, an ecological and remotely controlled behavioral test, and we observed normal learning. Finally, based on previous reports of other mutant lines suggesting that Ras-GRF1 may control body weight, we also measured this non-cognitive phenotype and we confirmed that both Ras-GRF1 deficient mutants are smaller than their control littermates. In conclusion, we demonstrate that Ras-GRF1 has no unique role in spatial memory while its function in contextual fear conditioning is likely to be due not only to its involvement in amygdalar functions but possibly to some distinct hippocampal connections specific to

  2. Septal membrane localization by C-terminal amphipathic α-helices of MinD in Bacillus subtilis mutant cells lacking MinJ or DivIVA.

    Ishikawa, Kazuki; Matsuoka, Satoshi; Hara, Hiroshi; Matsumoto, Kouji

    2017-10-18

    The Min system, which inhibits assembly of the cytokinetic protein FtsZ, is largely responsible for positioning the division site in rod-shaped bacteria. It has been reported that MinJ, which bridges DivIVA and MinD, is targeted to the cell poles by an interaction with DivIVA, and that MinJ in turn recruits MinCD to the cell poles. MinC, however, is located primarily at active division sites at mid-cell when expressed from its native promoter. Surprisingly, we found that Bacillus subtilis MinD is located at nascent septal membranes and at an asymmetric site on lateral membranes between nascent septal membranes in filamentous cells lacking MinJ or DivIVA. Bacillus subtilis MinD has two amphipathic α-helices rich in basic amino acid residues at its C-terminus; one of these, named MTS1 here, is the counterpart of the membrane targeting sequence (MTS) in Escherichia coli MinD while the other, named MTS-like sequence (MTSL), is the nearest helix to MTS1. These amphipathic helices were located independently at nascent septal membranes in cells lacking MinJ or DivIVA, whereas elimination of the helices from the wild type protein reduced its localization considerably. MinD variants with altered MTS1 and MTSL, in which basic amino acid residues were replaced with proline or acidic residues, were not located at nascent septal membranes, indicating that the binding to the nascent septal membranes requires basic residues and a helical structure. The septal localization of MTSL, but not of MTS1, was dependent on host cell MinD. These results suggest that MinD is targeted to nascent septal membranes via its C-terminal amphipathic α-helices in B. subtilis cells lacking MinJ or DivIVA. Moreover, the diffuse distribution of MinD lacking both MTSs suggests that only a small fraction of MinD depends on MinJ for its localization to nascent septal membranes.

  3. The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana

    Espineda, Cromwell E.; Linford, Alicia S.; Devine, Domenica; Brusslan, Judy A.

    1999-01-01

    Chlorophyll b is synthesized from chlorophyll a and is found in the light-harvesting complexes of prochlorophytes, green algae, and both nonvascular and vascular plants. We have used conserved motifs from the chlorophyll a oxygenase (CAO) gene from Chlamydomonas reinhardtii to isolate a homologue from Arabidopsis thaliana. This gene, AtCAO, is mutated in both leaky and null chlorina1 alleles, and DNA sequence changes cosegregate with the mutant phenotype. AtCAO mRNA levels are higher in three different mutants that have reduced levels of chlorophyll b, suggesting that plants that do not have sufficient chlorophyll b up-regulate AtCAO gene expression. Additionally, AtCAO mRNA levels decrease in plants that are grown under dim-light conditions. We have also found that the six major Lhcb proteins do not accumulate in the null ch1-3 allele. PMID:10468639

  4. Generation of mutant Uukuniemi viruses lacking the nonstructural protein NSs by reverse genetics indicates that NSs is a weak interferon antagonist.

    Rezelj, Veronica V; Överby, Anna K; Elliott, Richard M

    2015-05-01

    Uukuniemi virus (UUKV) is a tick-borne member of the Phlebovirus genus (family Bunyaviridae) and has been widely used as a safe laboratory model to study aspects of bunyavirus replication. Recently, a number of new tick-borne phleboviruses have been discovered, some of which, like severe fever with thrombocytopenia syndrome virus and Heartland virus, are highly pathogenic in humans. UUKV could now serve as a useful comparator to understand the molecular basis for the different pathogenicities of these related viruses. We established a reverse-genetics system to recover UUKV entirely from cDNA clones. We generated two recombinant viruses, one in which the nonstructural protein NSs open reading frame was deleted from the S segment and one in which the NSs gene was replaced with green fluorescent protein (GFP), allowing convenient visualization of viral infection. We show that the UUKV NSs protein acts as a weak interferon antagonist in human cells but that it is unable to completely counteract the interferon response, which could serve as an explanation for its inability to cause disease in humans. Uukuniemi virus (UUKV) is a tick-borne phlebovirus that is apathogenic for humans and has been used as a convenient model to investigate aspects of phlebovirus replication. Recently, new tick-borne phleboviruses have emerged, such as severe fever with thrombocytopenia syndrome virus in China and Heartland virus in the United States, that are highly pathogenic, and UUKV will now serve as a comparator to aid in the understanding of the molecular basis for the virulence of these new viruses. To help such investigations, we have developed a reverse-genetics system for UUKV that permits manipulation of the viral genome. We generated viruses lacking the nonstructural protein NSs and show that UUKV NSs is a weak interferon antagonist. In addition, we created a virus that expresses GFP and thus allows convenient monitoring of virus replication. These new tools represent a

  5. Hydroxymethylated Dioxobilins in Senescent Arabidopsis thaliana Leaves: Sign of a Puzzling Biosynthetic Intermezzo of Chlorophyll Breakdown.

    Süssenbacher, Iris; Kreutz, Christoph R; Christ, Bastien; Hörtensteiner, Stefan; Kräutler, Bernhard

    2015-08-10

    1-Formyl-19-oxobilin-type tetrapyrroles are characteristic, abundant products of chlorophyll breakdown in senescent leaves. However, in some leaves, 1,19-dioxobilin-type chlorophyll catabolites (DCCs) lacking the formyl group accumulate instead. A P450 enzyme was identified in in vitro studies that removed the formyl group of a primary fluorescent chlorophyll catabolite (pFCC) and generated fluorescent DCCs. These DCCs are precursors of isomeric nonfluorescent DCCs (NDCCs). Here, we report a structural investigation of the NDCCs in senescent leaves of wild-type Arabidopsis thaliana. Four new NDCCs were characterized, two of which carried a stereoselectively added hydroxymethyl group. Such formal DCC hydroxymethylations were previously found in DCCs in leaves of a mutant of A. thaliana. They are now indicated to be a feature of chlorophyll breakdown in A. thaliana, associated with the specific in vivo deformylation of pFCC en route to NDCCs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Radiation studies in Cajanus cajan: meiotic behaviour in some M/sub 2/ mutants

    Sinha, S.S.N.; Akhaury, S.B. (Ranchi Univ. (India). Dept. of Botany)

    1982-01-01

    A qualitative study of the mutants produced in M/sub 2/ generation has been made. The mutants were classified as: (1) chlorophyll mutant, (2) morphological mutant, (3) pollen mutant, (4) semi-sterile and (5) sterile mutant. Cytological investigations of pollen mutants, sterile and semi-sterile mutants have revealed that these mutants generally arise at higher dose levels (20 Kr and 25 Kr).

  7. Melatonin alleviates low PS I-limited carbon assimilation under elevated CO2 and enhances the cold tolerance of offspring in chlorophyll b-deficient mutant wheat

    Li, Xiangnan; Brestic, Marian; Tan, Dun-xian

    2018-01-01

    the activities of ATPase and sucrose synthesis and maintaining a relatively higher level of total chlorophyll concentration in leaves. In addition, melatonin priming in maternal plants at grain filling promoted the seed germination in offspring by accelerating the starch degradation and improved the cold...... tolerance of seedlings through activating the antioxidant enzymes and enhancing the photosynthetic electron transport efficiency. These findings suggest the important roles of melatonin in plant response to future climate change, indicating that the melatonin priming at grain filling in maternal plants...

  8. Chlorophyll b degradation by chlorophyll b reductase under high-light conditions.

    Sato, Rei; Ito, Hisashi; Tanaka, Ayumi

    2015-12-01

    The light-harvesting chlorophyll a/b binding protein complex of photosystem II (LHCII) is the main antenna complex of photosystem II (PSII). Plants change their LHCII content depending on the light environment. Under high-light conditions, the content of LHCII should decrease because over-excitation damages the photosystem. Chlorophyll b is indispensable for accumulating LHCII, and chlorophyll b degradation induces LHCII degradation. Chlorophyll b degradation is initiated by chlorophyll b reductase (CBR). In land plants, NON-YELLOW COLORING 1 (NYC1) and NYC1-Like (NOL) are isozymes of CBR. We analyzed these mutants to determine their functions under high-light conditions. During high-light treatment, the chlorophyll a/b ratio was stable in the wild-type (WT) and nol plants, and the LHCII content decreased in WT plants. The chlorophyll a/b ratio decreased in the nyc1 and nyc1/nol plants, and a substantial degree of LHCII was retained in nyc1/nol plants after the high-light treatment. These results demonstrate that NYC1 degrades the chlorophyll b on LHCII under high-light conditions, thus decreasing the LHCII content. After the high-light treatment, the maximum quantum efficiency of the PSII photochemistry was lower in nyc1 and nyc1/nol plants than in WT and nol plants. A larger light-harvesting system would damage PSII in nyc1 and nyc1/nol plants. The fluorescence spectroscopy of the leaves indicated that photosystem I was also damaged by the excess LHCII in nyc1/nol plants. These observations suggest that chlorophyll b degradation by NYC1 is the initial reaction for the optimization of the light-harvesting capacity under high-light conditions.

  9. Preliminary Study of the Characteristics of Several Glossy Cabbage (Brassica oleracea var. capitata L. Mutants

    Tang Jun

    2015-09-01

    Full Text Available To determine the characteristics and potential practical applications of glossy cabbage (Brassica oleracea var. capitata L. mutants, five different glossy mutants were studied. The amount of epicuticular wax covering the mutant leaves was only approximately 30% that of the wild-type (WT leaves. The wax crystals of WT plants were columnar and linear, while they were granular and rod-shaped in the mutants. Additionally, in WT cabbage, the primary wax components were alkanes, alcohols, fatty acids, ketones, and aldehydes. There was a significant decrease in the abundance of alkanes and ketones in the wax of the mutants. The glossy-green trait of the mutants may be the result of an inhibited alkane-forming pathway. Higher rates of chlorophyll leaching and water loss demonstrate that the mutant leaves were more permeable and sensitive to drought stress than the WT leaves. Growth curve results indicated that the growth rate of mutant-1 and mutant-3 was slower than that of the corresponding WT cabbage, resulting in shorter plants. However, the growth rate of mutant-2 was not influenced by the lack of coating wax. An investigation of the agronomic traits and heterosis of the glossy cabbage mutants indicated that all five mutants had glossy-green leaves, which was a favorable characteristic. The F1 plants derived from crosses involving mutant-2 exhibited obvious heterosis, suggesting the observed glossy-green trait is controlled by a dominant gene. Therefore, mutant-2 may be useful as a source of genetic material for future cabbage breeding experiments.

  10. Chlorophyll_Master

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included chlorophyll for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  11. OSU Chlorophyll Bloom Product

    National Oceanic and Atmospheric Administration, Department of Commerce — This product was developed for the Oregon coast based on the observed change between running 8-day composite chlorophyll-a (CHL) data obtained by the MODerate...

  12. Biological changes in Barley mutants resistant to powdery mildew disease

    Amer, I. M.; Fahim, M. M.; Moustafa, N. A.

    2012-12-01

    physiological studies showed that all kinds of chlorophyll (a), (b) and (a + b) content in infected plant were decreased while, the carotenes pigment were increased. Infection generally reduced total sugars content of all resistant mutants. Infected resistant mutant showed more phenols content and peroxidase, polyphenoloxidase activities than healthy ones of the mutants. (Author)

  13. Chlorophyll formation and phytochrome

    Raven, C.W.

    1973-01-01

    The rôle of phytochrome in the regeneration of protochlorophyll (Pchl) in darkness following short exposures to light, as well as in the accumulation of chlorophyll- a (Chl- a ) in continuous light in previously dark-grown seedlings of pea, bean,

  14. Pulse amplitude modulated chlorophyll fluorometer

    Greenbaum, Elias; Wu, Jie

    2015-12-29

    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  15. Liquid scintillation counting of chlorophyll

    Fric, F.; Horickova, B.; Haspel-Horvatovic, E.

    1975-01-01

    A precise and reproducible method of liquid scintillation counting was worked out for measuring the radioactivity of 14 C-labelled chlorophyll a and chlorophyll b solutions without previous bleaching. The spurious count rate caused by luminescence of the scintillant-chlorophyll system is eliminated by using a suitable scintillant and by measuring the radioactivity at 4 to 8 0 C after an appropriate time of dark adaptation. Bleaching of the chlorophyll solutions is necessary only for measuring of very low radioactivity. (author)

  16. Chlorophyll loss associated with heat-induced senescence in bentgrass.

    Jespersen, David; Zhang, Jing; Huang, Bingru

    2016-08-01

    Heat stress-induced leaf senescence is characterized by the loss of chlorophyll from leaf tissues. The objectives of this study were to examine genetic variations in the level of heat-induced leaf senescence in hybrids of colonial (Agrostis capillaris)×creeping bentgrass (Agrostis stolonifera) contrasting in heat tolerance, and determine whether loss of leaf chlorophyll during heat-induced leaf senescence was due to suppressed chlorophyll synthesis and/or accelerated chlorophyll degradation in the cool-season perennial grass species. Plants of two hybrid backcross genotypes ('ColxCB169' and 'ColxCB190') were exposed to heat stress (38/33°C, day/night) for 28 d in growth chambers. The analysis of turf quality, membrane stability, photochemical efficiency, and chlorophyll content demonstrated significant variations in the level of leaf senescence induced by heat stress between the two genotypes, with ColXCB169 exhibiting a lesser degree of decline in chlorophyll content, photochemical efficiency and membrane stability than ColXCB190. The assays of enzymatic activity or gene expression of several major chlorophyll-synthesizing (porphobilinogen deaminase, Mg-chelatase, protochlorophyllide-reductase) and chlorophyll-degrading enzymes (chlorophyllase, pheophytinase, and chlorophyll-degrading peroxidase) indicated heat-induced decline in leaf chlorophyll content was mainly due to accelerated chlorophyll degradation, as manifested by increased gene expression levels of chlorophyllase and pheophytinase, and the activity of pheophytinase (PPH), while chlorophyll-synthesizing genes and enzymatic activities were not differentially altered by heat stress in the two genotypes. The analysis of heat-induced leaf senescence of pph mutants of Arabidopsis further confirmed that PPH could be one enzymes that plays key roles in regulating heat-accelerated chlorophyll degradation. Further research on enzymes responsible in part for the loss of chlorophyll during heat

  17. The application of shortened upper leaf mutant in barley breeding

    Jin Hua

    2004-01-01

    The shortened upper leaf mutant was induced from Fuji Nigo by γ-ray irradiation. Fuji Nigo, the mutant, cross-cut F 1 , F 2 and back-cross F 1 , F 2 were used to analyze mutant heredity by comparative study. The yield, chlorophyll content, light intensity, dry matter of mutant were investigated. The results showed that (1) the mutant character was controlled by a couple of nuclear genes which were partial dominance; (2) the transmittance of the mutant colony was better than that of Fuji Nigo and bottom dry matter was much more than that of Fuji Nigo; (3) under the condition of high fertilizer and high plant population , the yield of mutant was higher than that of Fuji Nigo; (4) the content of chlorophyll a in the mutant was higher than that in Fuji Nigo

  18. Membrane composition and physiological activity of plastids from an oenothera plastome mutator-induced chloroplast mutant.

    Johnson, E M; Sears, B B

    1990-01-01

    Plastids were isolated from a plastome mutator-induced mutant (pm7) of Oenothera hookeri and were analyzed for various physiological and biochemical attributes. No photosynthetic electron transport activity was detected in the mutant plastids. This is consistent with previous ultrastructural analysis showing the absence of thylakoid membranes in the pm7 plastids and with the observation of aberrant processing and accumulation of chloroplast proteins in the mutant. In comparison to wild type, the mutant tissue lacks chlorophyll, and has significant differences in levels of four fatty acids. The analyses did not reveal any differences in carotenoid levels nor in the synthesis of several chloroplast lipids. The consequences of the altered composition of the chloroplast membrane are discussed in terms of their relation to the aberrant protein processing of the pm7 plastids. The pigment, fatty acid, and lipid measurements were also performed on two distinct nuclear genotypes (A/A and A/C) which differ in their compatibility with the plastid genome (type I) contained in these lines. In these cases, only chlorophyll concentrations differed significantly.

  19. Mutagentic effects of aerospace on Poa pratensis L.. Pt.2: Photosynthesis characters and chlorophyll contents

    Han Lei; Sun Zhenyuan; Ju Guansheng; Qian Yongqiang; Li Yinfeng; Peng Zhenhua

    2005-01-01

    The dry seeds of Poa pratensis L. 'Nassau' were carried by 'Shenzhou No.3' and three mutants were screened based on presentational characters from the treated plants and asexual reproduced them as PM 1 , PM 2 and PM 3 . The effects of the space environment on the photosynthesis characters and the contents of chlorophyll of the plants were investigated. Compared to CK, the contents of the chlorophyll a and b were reduced both in PM 1 and PM 3 , and the photosynthetic ability also decreased. The content of the chlorophyll in PM 2 increased greatly, but the ratio of the chlorophyll a/b was reduced, and the apparent quantum efficiency and the photosynthetic ability also decreased. The approximately CO 2 saturation point of the three mutants were higher than CK, but the CO 2 compensation points showed no difference between the mutants and CK. The carboxylation efficiency was PM 2 3 1 . (authors)

  20. Chlorobium tepidum mutant lacking bacteriochlorophyll c made by inactivation of the bchK gene, encoding bacteriochlorophyll c synthase

    Frigaard, Niels-Ulrik; Voigt, Ginny D; Bryant, Donald A

    2002-01-01

    of the BChl c antenna, the mutant grew about seven times slower than the wild type at light intensities that were limiting to the wild type (... found in the wild type, the bchK mutant should prove valuable for future analyses of the photosynthetic reaction center and of the roles of BChl a in photosynthesis in green bacteria. An evolutionary implication of our findings is that the photosynthetic ancestor of green sulfur bacteria could have...... evolved without chlorosomes and BChl c and instead used only BChl a-containing proteins as the major light-harvesting antennae....

  1. Chlorophyll b Reductase Plays an Essential Role in Maturation and Storability of Arabidopsis Seeds1[W

    Nakajima, Saori; Ito, Hisashi; Tanaka, Ryouichi; Tanaka, Ayumi

    2012-01-01

    Although seeds are a sink organ, chlorophyll synthesis and degradation occurs during embryogenesis and in a manner similar to that observed in photosynthetic leaves. Some mutants retain chlorophyll after seed maturation, and they are disturbed in seed storability. To elucidate the effects of chlorophyll retention on the seed storability of Arabidopsis (Arabidopsis thaliana), we examined the non-yellow coloring1 (nyc1)/nyc1-like (nol) mutants that do not degrade chlorophyll properly. Approximately 10 times more chlorophyll was retained in the dry seeds of the nyc1/nol mutant than in the wild-type seeds. The germination rates rapidly decreased during storage, with most of the mutant seeds failing to germinate after storage for 23 months, whereas 75% of the wild-type seeds germinated after 42 months. These results indicate that chlorophyll retention in the seeds affects seed longevity. Electron microscopic studies indicated that many small oil bodies appeared in the embryonic cotyledons of the nyc1/nol mutant; this finding indicates that the retention of chlorophyll affects the development of organelles in embryonic cells. A sequence analysis of the NYC1 promoter identified a potential abscisic acid (ABA)-responsive element. An electrophoretic mobility shift assay confirmed the binding of an ABA-responsive transcriptional factor to the NYC1 promoter DNA fragment, thus suggesting that NYC1 expression is regulated by ABA. Furthermore, NYC1 expression was repressed in the ABA-insensitive mutants during embryogenesis. These data indicate that chlorophyll degradation is induced by ABA during seed maturation to produce storable seeds. PMID:22751379

  2. Brucella abortus mutants lacking ATP-binding cassette transporter proteins are highly attenuated in virulence and confer protective immunity against virulent B. abortus challenge in BALB/c mice.

    Truong, Quang Lam; Cho, Youngjae; Park, Soyeon; Park, Bo-Kyoung; Hahn, Tae-Wook

    2016-06-01

    Brucella abortus RB51 is an attenuated vaccine strain that has been most frequently used for bovine brucellosis. Although it is known to provide good protection in cattle, it still has some drawbacks including resistance to rifampicin, residual virulence and pathogenicity in humans. Thus, there has been a continuous interest on new safe and effective bovine vaccine candidates. In the present study, we have constructed unmarked mutants by deleting singly cydD and cydC genes, which encode ATP-binding cassette transporter proteins, from the chromosome of the virulent Brucella abortus isolate from Korean cow (referred to as IVK15). Both IVK15ΔcydD and ΔcydC mutants showed increased sensitivity to metal ions, hydrogen peroxide and acidic pH, which are mimic to intracellular environment during host infection. Additionally, the mutants exhibited a significant growth defect in RAW264.7 cells and greatly attenuated in mice. Vaccination of mice with either IVK15ΔcydC or IVK15ΔcydD mutant could elicit an anti-Brucella specific immunoglobulin G (IgG) and IgG subclass responses as well as enhance the secretion of interferon-gamma, and provided better protection against challenge with B. abortus strain 2308 than with the commercial B. abortus strain RB51 vaccine. Collectively, these results suggest that both IVK15ΔcydC and IVK15ΔcydD mutants could be an attenuated vaccine candidate against B. abortus. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Production of the Bioactive Compounds Violacein and Indolmycin Is Conditional in a maeA Mutant of Pseudoalteromonas luteoviolacea S4054 Lacking the Malic Enzyme

    Schmidt Thøgersen, Mariane; Delpin, Marina; Melchiorsen, Jette

    2016-01-01

    cluster was not interrupted by the transposon; instead the insertion was located to the maeA gene encoding the malic enzyme. Supernatant of the mutant strain inhibited Vibrio anguillarum and Staphylococcus aureus in well diffusion assays and in MIC assays at the same level as the wild type strain...... of violacein and indolmycin may be metabolically linked and that yet unidentified antibacterial compound(s) may be play a role in the antibacterial activity of P. luteoviolacea....

  4. Influence of single and combination treatments of physical and chemical mutagen on chlorophyll mutations in Finger Millet

    Kumar, Binod; Mahto, Jaylal; Haider, Z.A.

    1993-01-01

    Gamma rays, ethyl methane sulfonate (EMS) and their combined treatments influenced differently in producing chlorophyll mutations. A good number of chlorophyll mutants with varied frequencies were recorded in M 2 generation. The frequency of chlorophyll mutants was higher at lower doses of gamma rays, EMS and their combination treatments. The most frequently observed mutant was Albino type. The other chlorophyll mutants isolated were Xantha, Viridis, Striata and Tigrina. The frequency of tigrina and striata was lowest in variety A-404 and Hr-374, respectively. The efficiency and effectiveness was high at the lower doses of mutagens in both the varieties. EMS (0.2%) was more effective than the corresponding lower dose of gamma rays for both the varieties. (author). 10 refs., 4 tabs

  5. Photosynthetic characterization of a rolled leaf mutant of rice ( Oryza ...

    A new rolling leaf rice mutant was identified which showed an apparently straighter longitudinal shape normal transverse rolling characters at all developing stages. The chlorophyll contents per fresh weight of this mutant leaves were lower than those of wild-type. The electron transfer rate (ETR) and photochemical ...

  6. Chlorophyll d: the puzzle resolved

    Larkum, Anthony W D; Kühl, Michael

    2005-01-01

    Chlorophyll a (Chl a) has always been regarded as the sole chlorophyll with a role in photochemical conversion in oxygen-evolving phototrophs, whereas chlorophyll d (Chl d), discovered in small quantities in red algae in 1943, was often regarded as an artefact of isolation. Now, as a result...... of discoveries over the past year, it has become clear that Chl d is the major chlorophyll of a free-living and widely distributed cyanobacterium that lives in light environments depleted in visible light and enhanced in infrared radiation. Moreover, Chl d not only has a light-harvesting role but might also...... replace Chl a in the special pair of chlorophylls in both reactions centers of photosynthesis. Udgivelsesdato: 2005-Aug...

  7. Evaluation of Chlorophyll Content and Chlorophyll Fluorescence Parameters and Relationships between Chlorophyll a, b and Chlorophyll Content Index under Water Stress in Olea europaea cv. Dezful

    E. Khaleghi; K. Arzani; N. Moallemi; M. Barzegar

    2012-01-01

    This study was conducted to determine effect of water stress on chlorophyll content and chlorophyll fluorescence parameter in young `Dezful- olive trees. Three irrigation regimes (40% ETcrop, 65% ETcrop and 100% ETcrop) were used. After irrigation treatments were applied, some of biochemical parameters including chlorophyll a, b, total chlorophyll, chlorophyll fluorescence and also chlorophyll content index (C.C.I) were measured. Results of Analysis of variance showed that irrigation treatmen...

  8. Membrane Composition and Physiological Activity of Plastids from an Oenothera Plastome Mutator-Induced Chloroplast Mutant 1

    Johnson, Ellen M.; Sears, Barbara B.

    1990-01-01

    Plastids were isolated from a plastome mutator-induced mutant (pm7) of Oenothera hookeri and were analyzed for various physiological and biochemical attributes. No photosynthetic electron transport activity was detected in the mutant plastids. This is consistent with previous ultrastructural analysis showing the absence of thylakoid membranes in the pm7 plastids and with the observation of aberrant processing and accumulation of chloroplast proteins in the mutant. In comparison to wild type, the mutant tissue lacks chlorophyll, and has significant differences in levels of four fatty acids. The analyses did not reveal any differences in carotenoid levels nor in the synthesis of several chloroplast lipids. The consequences of the altered composition of the chloroplast membrane are discussed in terms of their relation to the aberrant protein processing of the pm7 plastids. The pigment, fatty acid, and lipid measurements were also performed on two distinct nuclear genotypes (A/A and A/C) which differ in their compatibility with the plastid genome (type I) contained in these lines. In these cases, only chlorophyll concentrations differed significantly. PMID:16667256

  9. Plant cells without detectable plastids are generated in the crumpled leaf mutant of Arabidopsis thaliana.

    Chen, Yuling; Asano, Tomoya; Fujiwara, Makoto T; Yoshida, Shigeo; Machida, Yasunori; Yoshioka, Yasushi

    2009-05-01

    Plastids are maintained in cells by proliferating prior to cell division and being partitioned to each daughter cell during cell division. It is unclear, however, whether cells without plastids are generated when plastid division is suppressed. The crumpled leaf (crl) mutant of Arabidopsis thaliana is a plastid division mutant that displays severe abnormalities in plastid division and plant development. We show that the crl mutant contains cells lacking detectable plastids; this situation probably results from an unequal partitioning of plastids to each daughter cell. Our results suggest that crl has a partial defect in plastid expansion, which is suggested to be important in the partitioning of plastids to daughter cells when plastid division is suppressed. The absence of cells without detectable plastids in the accumulation and replication of chloroplasts 6 (arc6) mutant, another plastid division mutant of A. thaliana having no significant defects in plant morphology, suggests that the generation of cells without detectable plastids is one of the causes of the developmental abnormalities seen in crl plants. We also demonstrate that plastids with trace or undetectable amounts of chlorophyll are generated from enlarged plastids by a non-binary fission mode of plastid replication in both crl and arc6.

  10. A structural investigation of the central chlorophyll a binding sites in the minor photosystem II antenna protein, Lhcb4

    Pascal, Andy; Caffarri, Stefano; Croce, Roberta; Sandonà, Dorianna; Bassi, Roberto; Robert, Bruno

    2002-01-01

    Mutant proteins from light-harvesting complexes of higher plants may be obtained by expressing modified apoproteins in Escherichia coli, and reconstituting them in the presence of chlorophyll and carotenoid cofactors. This method has allowed, in particular, the engineering of mutant LHCs in which

  11. Remobilization of Phytol from Chlorophyll Degradation Is Essential for Tocopherol Synthesis and Growth of Arabidopsis

    vom Dorp, Katharina; Hölzl, Georg; Plohmann, Christian; Eisenhut, Marion; Abraham, Marion

    2015-01-01

    Phytol from chlorophyll degradation can be phosphorylated to phytyl-phosphate and phytyl-diphosphate, the substrate for tocopherol (vitamin E) synthesis. A candidate for the phytyl-phosphate kinase from Arabidopsis thaliana (At1g78620) was identified via a phylogeny-based approach. This gene was designated VITAMIN E DEFICIENT6 (VTE6) because the leaves of the Arabidopsis vte6 mutants are tocopherol deficient. The vte6 mutant plants are incapable of photoautotrophic growth. Phytol and phytyl-phosphate accumulate, and the phytyl-diphosphate content is strongly decreased in vte6 leaves. Phytol feeding and enzyme assays with Arabidopsis and recombinant Escherichia coli cells demonstrated that VTE6 has phytyl-P kinase activity. Overexpression of VTE6 resulted in increased phytyl-diphosphate and tocopherol contents in seeds, indicating that VTE6 encodes phytyl-phosphate kinase. The severe growth retardation of vte6 mutants was partially rescued by introducing the phytol kinase mutation vte5. Double mutant plants (vte5 vte6) are tocopherol deficient and contain more chlorophyll, but reduced amounts of phytol and phytyl-phosphate compared with vte6 mutants, suggesting that phytol or phytyl-phosphate are detrimental to plant growth. Therefore, VTE6 represents the missing phytyl-phosphate kinase, linking phytol release from chlorophyll with tocopherol synthesis. Moreover, tocopherol synthesis in leaves depends on phytol derived from chlorophyll, not on de novo synthesis of phytyl-diphosphate from geranylgeranyl-diphosphate. PMID:26452599

  12. Photosynthetic bark: use of chlorophyll absorption continuum index to estimate Boswellia papyrifera bark chlorophyll content

    Girma, A.; Skidmore, A.K.; Bie, de C.A.J.M.; Bongers, F.; Schlerf, M.

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

  13. Photosynthetic bark : use of chlorophyll absorption continuum index to estimate Boswellia papyrifera bark chlorophyll content

    Girma Gebrekidan, A.; Skidmore, A.K.; de Bie, C.A.J.M.; Bongers, Frans; Schlerf, Martin; Schlerf, M.

    2013-01-01

    Quantification of chlorophyll content provides useful insight into the physiological performance of plants. Several leaf chlorophyll estimation techniques, using hyperspectral instruments, are available. However, to our knowledge, a non-destructive bark chlorophyll estimation technique is not

  14. Lack of TNF-alpha receptor type 2 protects motor neurons in a cellular model of amyotrophic lateral sclerosis and in mutant SOD1 mice but does not affect disease progression.

    Tortarolo, Massimo; Vallarola, Antonio; Lidonnici, Dario; Battaglia, Elisa; Gensano, Francesco; Spaltro, Gabriella; Fiordaliso, Fabio; Corbelli, Alessandro; Garetto, Stefano; Martini, Elisa; Pasetto, Laura; Kallikourdis, Marinos; Bonetto, Valentina; Bendotti, Caterina

    2015-10-01

    Changes in the homeostasis of tumor necrosis factor α (TNFα) have been demonstrated in patients and experimental models of amyotrophic lateral sclerosis (ALS). However, the contribution of TNFα to the development of ALS is still debated. TNFα is expressed by glia and neurons and acts through the membrane receptors TNFR1 and TNFR2, which may have opposite effects in neurodegeneration. We investigated the role of TNFα and its receptors in the selective motor neuron death in ALS in vitro and in vivo. TNFR2 expressed by astrocytes and neurons, but not TNFR1, was implicated in motor neuron loss in primary SOD1-G93A co-cultures. Deleting TNFR2 from SOD1-G93A mice, there was partial but significant protection of spinal motor neurons, sciatic nerves, and tibialis muscles. However, no improvement of motor impairment or survival was observed. Since the sciatic nerves of SOD1-G93A/TNFR2-/- mice showed high phospho-TAR DNA-binding protein 43 (TDP-43) accumulation and low levels of acetyl-tubulin, two indices of axonal dysfunction, the lack of symptom improvement in these mice might be due to impaired function of rescued motor neurons. These results indicate the interaction between TNFR2 and membrane-bound TNFα as an innovative pathway involved in motor neuron death. Nevertheless, its inhibition is not sufficient to stop disease progression in ALS mice, underlining the complexity of this pathology. We show evidence of the involvement of neuronal and astroglial TNFR2 in the motor neuron degeneration in ALS. Both concur to cause motor neuron death in primary astrocyte/spinal neuron co-cultures. TNFR2 deletion partially protects motor neurons and sciatic nerves in SOD1-G93A mice but does not improve their symptoms and survival. However, TNFR2 could be a new target for multi-intervention therapies. © 2015 International Society for Neurochemistry.

  15. The magnesium chelation step in chlorophyll biosynthesis

    Weinstein, J.D.

    1991-01-01

    The biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins and lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX. Insertion of iron leads to heme, while insertion of magnesium leads to chlorophyll. The Mg-chelatase from intact cucumber chloroplasts has been characterized with regard to substrate specificity, regulation, ATP requirement, and a requirement for intact chloroplasts. Mg-chelatase was isolated from maize, barley and peas and characterized in order to circumvent the intact chloroplast requirement of cucumber Mg-chelatase. Pea Mg-chelatase activity is higher than cucumber Mg-chelatase activity, and lacks the requirement for intact chloroplasts. Studies on isolated pea Mg-chelatase have shown more cofactors are required for the reaction than are seen with ferrochelatase, indicating a greater opportunity for regulatory control of this pathway. Two of the cofactors are proteins, and there appears to be a requirement for a protease-sensitive component which is outside the outer envelope. We are developing a continuous spectrophotometric assay for Mg-chelatase activity, and an assay for free heme which has shown heme efflux from intact chloroplasts. 18 refs. (MHB)

  16. Complexes and aggregates of chlorophylls

    Kooyman, R.P.H.

    1980-01-01

    Chlorophyll (Chl) molecules can form complexes in two important ways: by ligation at the magnesium atom and/or by hydrogen bonding at the keto- carbonyl group. Under certain conditions these processes may give rise to dimer formation. This thesis describes some properties of complexes and dimers of

  17. Isolation and characterization of two chlorophyll-deficient genes in soybean

    We have identified a viable-yellow and a lethal-yellow mutant in soybean. The three phenotypes green, lethal- and viable-yellow were easily distinguished based on their light reflectance indices, chlorophyll abundance and photochemical conversion efficiency. Photochemical conversion efficiency was r...

  18. Mutations for chlorophyll deficiency in barley: comparative effects of physical and chemical mutagens

    Constantin, M.J.

    1975-01-01

    The report concerns a comparison of effects from gamma rays, fission neutrons, and ethylmethane sulfonate based on chlorophyll-deficient mutant seedlings. Data from the literature and from the author's research are reviewed, and results are related to the practical application of mutation induction in barley breeding. (BSC) [de

  19. Characterization of chlorophyll binding to LIL3.

    Mork-Jansson, Astrid Elisabeth; Eichacker, Lutz Andreas

    2018-01-01

    The light harvesting like protein 3 (LIL 3) from higher plants, has been linked to functions in chlorophyll and tocopherol biosynthesis, photo-protection and chlorophyll transfer. However, the binding of chlorophyll to LIL3 is unclear. We present a reconstitution protocol for chlorophyll binding to LIL3 in DDM micelles. It is shown in the absence of lipids and carotenoids that reconstitution of chlorophyll binding to in vitro expressed LIL3 requires pre-incubation of reaction partners at room temperature. We show chlorophyll a but not chlorophyll b binding to LIL3 at a molar ratio of 1:1. Neither dynamic light scattering nor native PAGE, enabled a discrimination between binding of chlorophyll a and/or b to LIL3.

  20. Simple extraction methods that prevent the artifactual conversion of chlorophyll to chlorophyllide during pigment isolation from leaf samples.

    Hu, Xueyun; Tanaka, Ayumi; Tanaka, Ryouichi

    2013-06-19

    When conducting plant research, the measurement of photosynthetic pigments can provide basic information on the physiological status of a plant. High-pressure liquid chromatography (HPLC) is becoming widely used for this purpose because it provides an accurate determination of a variety of photosynthetic pigments simultaneously. This technique has a drawback compared with conventional spectroscopic techniques, however, in that it is more prone to structural modification of pigments during extraction, thus potentially generating erroneous results. During pigment extraction procedures with acetone or alcohol, the phytol side chain of chlorophyll is sometimes removed, forming chlorophyllide, which affects chlorophyll measurement using HPLC. We evaluated the artifactual chlorophyllide production during chlorophyll extraction by comparing different extraction methods with wild-type and mutant Arabidopsis leaves that lack the major isoform of chlorophyllase. Several extraction methods were compared to provide alternatives to researchers who utilize HPLC for the analysis of chlorophyll levels. As a result, the following three methods are recommended. In the first method, leaves are briefly boiled prior to extraction. In the second method, grinding and homogenization of leaves are performed at sub-zero temperatures. In the third method, N, N'-dimethylformamide (DMF) is used for the extraction of pigments. When compared, the first two methods eliminated almost all chlorophyllide-forming activity in Arabidopsis thaliana, Glebionis coronaria, Pisum sativum L. and Prunus sargentii Rehd. However, DMF effectively suppressed the activity of chlorophyllase only in Arabidopsis leaves. Chlorophyllide production in leaf extracts is predominantly an artifact. All three methods evaluated in this study reduce the artifactual production of chlorophyllide and are thus suitable for pigment extraction for HPLC analysis. The boiling method would be a practical choice when leaves are not too

  1. Isolation of chlorophyll a from spinach leaves

    E.D. Dikio

    2008-08-01

    Full Text Available An efficient method for separating chlorophyll a from spinach leaves by column chromatography and solvent extraction techniques has been developed. The purity and identity of the chlorophyll a have been confirmed by UV-Vis, IR and mass spectrometry. Yields from 100 g of freeze-dried spinach were 23 – 24 mg of chlorophyll a.

  2. Relationship between chlorophyll density and SPAD chlorophyll meter reading for Jerusalem artichoke (Helianthus tuberosus L.)

    Chlorophyll is an indicator of crop health and productivity. Measuring chlorophyll is usually done directly and requires significant time and resources. Indirect measurement of chlorophyll density using a handheld portable chlorophyll meter can reduce time. However, this information is very limit...

  3. Control of quantum interference of an excitonic wave in a chlorophyll chain with a chlorophyll ring

    Hong, Suc-Kyoung; Nam, Seog-Woo; Yeon, Kyu-Hwang

    2010-01-01

    The quantum interference of an excitonic wave and its coherent control in a nanochain with a nanoring are studied. The nanochain is comprised of six chlorophylls, where four chlorophylls compose the nanoring and two chlorophylls are attached at two opposite sites on the nanoring. The exciton dynamics and the correlation of the excitation between chlorophylls are analyzed for a given configurational arrangement and dipolar orientation of the chlorophylls. The results of this study show that the excitation at specified chlorophylls is suppressed or enhanced by destructive or constructive interference of the excitonic wave in the chlorophyll nanochain.

  4. Rubisco mutants of Chlamydomonas reinhardtii enhance photosynthetic hydrogen production.

    Pinto, T S; Malcata, F X; Arrabaça, J D; Silva, J M; Spreitzer, R J; Esquível, M G

    2013-06-01

    Molecular hydrogen (H2) is an ideal fuel characterized by high enthalpy change and lack of greenhouse effects. This biofuel can be released by microalgae via reduction of protons to molecular hydrogen catalyzed by hydrogenases. The main competitor for the reducing power required by the hydrogenases is the Calvin cycle, and rubisco plays a key role therein. Engineered Chlamydomonas with reduced rubisco levels, activity and stability was used as the basis of this research effort aimed at increasing hydrogen production. Biochemical monitoring in such metabolically engineered mutant cells proceeded in Tris/acetate/phosphate culture medium with S-depletion or repletion, both under hypoxia. Photosynthetic activity, maximum photochemical efficiency, chlorophyll and protein levels were all measured. In addition, expression of rubisco, hydrogenase, D1 and Lhcb were investigated, and H2 was quantified. At the beginning of the experiments, rubisco increased followed by intense degradation. Lhcb proteins exhibited monomeric isoforms during the first 24 to 48 h, and D1 displayed sensitivity under S-depletion. Rubisco mutants exhibited a significant decrease in O2 evolution compared with the control. Although the S-depleted medium was much more suitable than its complete counterpart for H2 production, hydrogen release was observed also in sealed S-repleted cultures of rubisco mutated cells under low-moderate light conditions. In particular, the rubisco mutant Y67A accounted for 10-15-fold higher hydrogen production than the wild type under the same conditions and also displayed divergent metabolic parameters. These results indicate that rubisco is a promising target for improving hydrogen production rates in engineered microalgae.

  5. Radiation induced mutants in cape-gooseberry (Physalis peruviana L.)

    Gupta, S.K.; Roy, S.K.

    1986-01-01

    Dry seeds of Physalis peruviana (n=24) were irradiated with different doses of gamma-rays. The M 1 plants were grown to maturity and their seeds collected and sown separately for M 2 generation. Mutants were isolated from M 2 seedlings and plants. Mutant characters obtained were virido-albino chlorophyllous, high yielding, small leaf and fruit, semi-sterile and curly leaf type etc. The high yielding and small leaf and fruit mutants bred true in M 3 and M 4 generation reproducing the characters of the M 2 generation. (author)

  6. Chlorophyll Degradation: The Tocopherol Biosynthesis-Related Phytol Hydrolase in Arabidopsis Seeds Is Still Missing1[C][W][OPEN

    Zhang, Wei; Liu, Tianqi; Ren, Guodong; Hörtensteiner, Stefan; Zhou, Yongming; Cahoon, Edgar B.; Zhang, Chunyu

    2014-01-01

    Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type over-expressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis. PMID:25059706

  7. Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis.

    Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E; Chen, Ming; Zhou, Yongming; Yu, Bin; Cahoon, Edgar B

    2015-08-01

    Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. © 2015 American Society of

  8. Near infrared fluorescent chlorophyll nanoscale liposomes for sentinel lymph node mapping

    Fan, Lina; Wu, Qiang; Chu, Maoquan

    2012-01-01

    Background Sentinel lymph node (SLN) mapping using in vivo near infrared fluorescence imaging has attracted great attention during the past few years. Here we report on the early use of poorly water-soluble chlorophyll with near infrared fluorescence extracted from the leaf of Chimonanthus salicifolius, for mouse axillary SLN mapping. Methods and results To improve the water solubility and SLN targeting of the chlorophyll, we encapsulated the chlorophyll in nanoscale liposomes. The liposome-coated chlorophyll nanocomposites obtained were spherical in shape and had an average diameter of 21.7 ± 6.0 nm. The nanocomposites dispersed well in water, and in aqueous suspension they exhibited brighter near infrared fluorescence than chlorophyll alone. After incubation of the nanocomposites with normal liver cells (QSG-7701) and macrophage cells (Ana-1) for no more than 48 hours, there was no obvious reduction in cell viability. When the nanocomposites were injected intradermally into the paw of a mouse, the axillary SLN was found to be strongly fluorescent and was easily visualized in real time without a requirement for surgery. The intensity of the near infrared fluorescence emitted by the SLN was obviously brighter than that emitted by the SLN of another mouse that had been intradermally injected with chlorophyll alone. Conclusion Our data show that the liposome-coated chlorophyll nanocomposites could have great potential for clinical SLN mapping due to their lack of toxicity, bright near infrared fluorescence, and small diameter. PMID:22787402

  9. Distribution of nutrients, chlorophyll and phytoplankton primary ...

    Distribution of nutrients, chlorophyll and phytoplankton primary production in ... Two cruises were undertaken in the vicinity of the Cape Frio upwelling cell ... and concentrations of nitrate, phosphate, silicate, oxygen and chlorophyll a. ... Estimates of the annual primary production for each of the water bodies were calculated.

  10. Comparative Analysis of Light-Harvesting Antennae and State Transition in chlorina and cpSRP Mutants1[OPEN

    Wang, Peng

    2016-01-01

    State transitions in photosynthesis provide for the dynamic allocation of a mobile fraction of light-harvesting complex II (LHCII) to photosystem II (PSII) in state I and to photosystem I (PSI) in state II. In the state I-to-state II transition, LHCII is phosphorylated by STN7 and associates with PSI to favor absorption cross-section of PSI. Here, we used Arabidopsis (Arabidopsis thaliana) mutants with defects in chlorophyll (Chl) b biosynthesis or in the chloroplast signal recognition particle (cpSRP) machinery to study the flexible formation of PS-LHC supercomplexes. Intriguingly, we found that impaired Chl b biosynthesis in chlorina1-2 (ch1-2) led to preferentially stabilized LHCI rather than LHCII, while the contents of both LHCI and LHCII were equally depressed in the cpSRP43-deficient mutant (chaos). In view of recent findings on the modified state transitions in LHCI-deficient mutants (Benson et al., 2015), the ch1-2 and chaos mutants were used to assess the influence of varying LHCI/LHCII antenna size on state transitions. Under state II conditions, LHCII-PSI supercomplexes were not formed in both ch1-2 and chaos plants. LHCII phosphorylation was drastically reduced in ch1-2, and the inactivation of STN7 correlates with the lack of state transitions. In contrast, phosphorylated LHCII in chaos was observed to be exclusively associated with PSII complexes, indicating a lack of mobile LHCII in chaos. Thus, the comparative analysis of ch1-2 and chaos mutants provides new evidence for the flexible organization of LHCs and enhances our understanding of the reversible allocation of LHCII to the two photosystems. PMID:27663408

  11. Comparative Analysis of Light-Harvesting Antennae and State Transition in chlorina and cpSRP Mutants.

    Wang, Peng; Grimm, Bernhard

    2016-11-01

    State transitions in photosynthesis provide for the dynamic allocation of a mobile fraction of light-harvesting complex II (LHCII) to photosystem II (PSII) in state I and to photosystem I (PSI) in state II. In the state I-to-state II transition, LHCII is phosphorylated by STN7 and associates with PSI to favor absorption cross-section of PSI. Here, we used Arabidopsis (Arabidopsis thaliana) mutants with defects in chlorophyll (Chl) b biosynthesis or in the chloroplast signal recognition particle (cpSRP) machinery to study the flexible formation of PS-LHC supercomplexes. Intriguingly, we found that impaired Chl b biosynthesis in chlorina1-2 (ch1-2) led to preferentially stabilized LHCI rather than LHCII, while the contents of both LHCI and LHCII were equally depressed in the cpSRP43-deficient mutant (chaos). In view of recent findings on the modified state transitions in LHCI-deficient mutants (Benson et al., 2015), the ch1-2 and chaos mutants were used to assess the influence of varying LHCI/LHCII antenna size on state transitions. Under state II conditions, LHCII-PSI supercomplexes were not formed in both ch1-2 and chaos plants. LHCII phosphorylation was drastically reduced in ch1-2, and the inactivation of STN7 correlates with the lack of state transitions. In contrast, phosphorylated LHCII in chaos was observed to be exclusively associated with PSII complexes, indicating a lack of mobile LHCII in chaos Thus, the comparative analysis of ch1-2 and chaos mutants provides new evidence for the flexible organization of LHCs and enhances our understanding of the reversible allocation of LHCII to the two photosystems. © 2016 American Society of Plant Biologists. All Rights Reserved.

  12. Quantifying mangrove chlorophyll from high spatial resolution imagery

    Heenkenda, M.K.; Joyce, K.E.; Maier, S.W.; Bruin, de S.

    2015-01-01

    Lower than expected chlorophyll concentration of a plant can directly limit photosynthetic activity, and resultant primary production. Low chlorophyll concentration may also indicate plant physiological stress. Compared to other terrestrial vegetation, mangrove chlorophyll variations are poorly

  13. PNRI mutant variety: sansevieria 'Sword of Ibe'

    Aurigue, Fernando B.

    2011-01-01

    Sansevieria 'Sword of Ibe,' registered by the Philippine Nuclear Research Institute as NSIC 2008 Or-66, is a chlorophyll mutant of Sansevieria trifasciata 'Moonshine' developed by treating its suckers or shoots arising from a rhizome with acute gamma radiation from a Cobalt-60 source. The new mutant is identical in growth habit and vigor to Sansevieria 'Moonshine,' also known as Moonglow. Results of this mutation breeding experiment showed that leaf color and flowering were altered by gamma irradiation without changing the other characteristics of the plant. Propagation is true-to-type by separation of sucker and top cutting. The plant is recommended for use as landscaping material and as pot plant for indoor and outdoor use. The leaves may be harvested as cut foliage for Japanese flower arrangements. (author)

  14. Radiation induced chlorophyll mutations in rice

    Bari, G.; Mustafa, G.; Soomro, A.M.; Baloch, A.W.

    1985-01-01

    Air dried grains of four local varieties of rice were treated with gamma-rays and fast neutrons for determining their mutagenic effectiveness through the occurence of chlorophyll mutations. Fast neutrons were more effective in inducing chlorophyll mutations and the rice variety Basmati 370 produced maximum number of mutations followed by varieties Sonahri Sugdasi, Jajai 77 and Sada Gulab. The highest frequency of chlorophyll mutations was that of albina types followed by striata types. The xantha, viridis and tigrina types of mutations were less frequent. (authors)

  15. Seasonal Composite Chlorophyll Concentrations - Gulf of Maine

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are seasonal composites, and were calculated...

  16. EmpiricalValues_Chlorophyll_GrandComposite

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are a composite of several years (1997-2005)...

  17. Monthly Composite Chlorophyll Concentrations - Gulf of Maine

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are monthly composites, and were calculated...

  18. Selection of mutants of capsicum annuum induced by gamma ray

    Lee, Y. I.; Lee, Y. B. [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of); Lee, E. K. [Chungnam National Univ., Taejeon (Korea, Republic of)

    1998-06-01

    For induction and selection of mutations of Capsicum annuum L., dry seeds of pure lines No.1 and No.2 were irradiated with gamma ray of 150Gy, 200Gy and 250Gy. Various mutants were selected such as showing early maturity, short plant height, long fruit and chlorophyll mutations. Mutation frequency of No.1 line was 3.4% in the dose of 150Gy, while the frequency of No.2 line was 2.7% in the dose of 250Gy. For selection of resistant mutant to amino acid analog, the optimum concentration of 5-methyltryptophan (5-MT) and S-(2-aminoethyl)-L-cysteine were 25 ppm and 30 ppm, respectively. Four resistant mutant lines to 5-MT were selected among 400 mutant lines.

  19. Organization of chlorophyll biosynthesis and insertion of chlorophyll into the chlorophyll-binding proteins in chloroplasts.

    Wang, Peng; Grimm, Bernhard

    2015-12-01

    Oxygenic photosynthesis requires chlorophyll (Chl) for the absorption of light energy, and charge separation in the reaction center of photosystem I and II, to feed electrons into the photosynthetic electron transfer chain. Chl is bound to different Chl-binding proteins assembled in the core complexes of the two photosystems and their peripheral light-harvesting antenna complexes. The structure of the photosynthetic protein complexes has been elucidated, but mechanisms of their biogenesis are in most instances unknown. These processes involve not only the assembly of interacting proteins, but also the functional integration of pigments and other cofactors. As a precondition for the association of Chl with the Chl-binding proteins in both photosystems, the synthesis of the apoproteins is synchronized with Chl biosynthesis. This review aims to summarize the present knowledge on the posttranslational organization of Chl biosynthesis and current attempts to envision the proceedings of the successive synthesis and integration of Chl into Chl-binding proteins in the thylakoid membrane. Potential auxiliary factors, contributing to the control and organization of Chl biosynthesis and the association of Chl with the Chl-binding proteins during their integration into photosynthetic complexes, are discussed in this review.

  20. Mediterranean Ocean Colour Chlorophyll Trends.

    Colella, Simone; Falcini, Federico; Rinaldi, Eleonora; Sammartino, Michela; Santoleri, Rosalia

    2016-01-01

    In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity). Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication). Monitoring chlorophyll (Chl) concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the "good environmental status" (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020) and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean) algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I) and coastal (i.e., Case II) waters. We apply the Mann-Kendall test and the Sens's method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However, the trends

  1. Mediterranean Ocean Colour Chlorophyll Trends.

    Simone Colella

    Full Text Available In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity. Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication. Monitoring chlorophyll (Chl concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the "good environmental status" (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020 and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I and coastal (i.e., Case II waters. We apply the Mann-Kendall test and the Sens's method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However

  2. Synergistic interaction of gamma rays and some metallic salts in the induction of chlorophyll mutations in rice

    Reddy, T.P.; Vaidyanath, K.

    1978-01-01

    In this study the mutagenic activity of 9 metallic salts was tested in comparison and conjunction with gamma rays on rice seed. In M 2 , barium and cadmium produced chlorophyll mutation and mutant frequencies on a par with those of 20 kR gamma rays. Similarly, copper and mercury induced moderately high mutation and mutant frequencies. Salts of strontium, iron and lead showed rather weak mutagenic effects. On the other hand, two metals - manganese anc calcium - failed to provoke chlorophyll mutations in rice seed. Sequential treatments of gamma rays + 5 metals, namely Sr, Cd, Hg, Pb and Cu, produced synergistic yields of chlorophyll mutants in the M 2 generation. Two genetically active metals, Ba and Fe, showed less than additive effects when post-treated after gamma irradiation. Manganese, which failed to induce chlorophyll mutations in independent treatment, potentiated the mutagenic activity of gamma radiation in sequential treatment. On the other hand, sequential treatment with calcium seemed to confer a substantial protection against gamma-ray-induced genetic lesions. The probable mechanisms of synergistic interaction, mutagenic potentiation and protection, observed in sequential treatments, are discussed. (Auth.)

  3. Reduced alcohol consumption in mice lacking preprodynorphin.

    Blednov, Yuri A; Walker, Danielle; Martinez, Marni; Harris, R Adron

    2006-10-01

    Many studies suggest a role for endogenous opioid peptides and their receptors in regulation of ethanol intake. It is commonly accepted that the kappa-opioid receptors and their endogenous ligands, dynorphins, produce a dysphoric state and therefore may be responsible for avoidance of alcohol. We used mutant mice lacking preprodynorphin in a variety of behavioral tests of alcohol actions. Null mutant female, but not male, mice showed significantly lower preference for alcohol and consumed lower amounts of alcohol in a two-bottle choice test as compared with wild-type littermates. In the same test, knockout mice of both sexes showed a strong reduction of preference for saccharin compared to control mice. In contrast, under conditions of limited (4 h) access (light phase of the light/dark cycle), null mutant mice did not show any differences in consumption of saccharin, but they showed significantly reduced intake of sucrose. To determine the possible cause for reduction of ethanol preference and intake, we studied other ethanol-related behaviors in mice lacking the preprodynorphin gene. There were no differences between null mutant and wild-type mice in ethanol-induced loss of righting reflex, acute ethanol withdrawal, ethanol-induced conditioned place preference, or conditioned taste aversion to ethanol. These results indicate that deletion of preprodynorphin leads to substantial reduction of alcohol intake in female mice, and suggest that this is caused by decreased orosensory reward of alcohol (sweet taste and/or palatability).

  4. Mutagenic effects of gamma rays and EMS on frequency and spectrum of chlorophyll mutations in urdbean (Vigna mungo (L.) Hepper)

    Usharani, K.S.; Ananda Kumar, C.R.

    2015-01-01

    Chlorophyll mutations act as a significant index in the judgment of induced genetic variations in mutagen treated populations. Different types of chlorophyll mutation have been observed in various crop plants. In the current study, the effect of different concentrations (40 kR, 50 kR and 60 kR) of gamma rays, Ethyl Methane Sulphonate (50 mM, 60 mM and 70 mM) in single and combination dose/concentration on the frequency and spectrum of chlorophyll mutation and the effect of VBN 4 urdbean variety to such irradiation dose was observed. Results showed induction of broad spectrum of chlorophyll mutations which included albina, xantha, chlorina and viridis. Among these chlorina type was predominant in all the mutagenic treatments. The albina type of chlorophyll mutants occurred very rarely and was found only at 60 mM of EMS treatment and at 40 kR + 50 mM, 60 kR + 70 mM of combination treatments. Based on the chlorophyll mutation frequency, gamma rays were most effective followed by EMS and combination of treatments. (author)

  5. The chlorophyll-deficient golden leaf mutation in cucumber is due to a single nucleotide substitution in CsChlI for magnesium chelatase I subunit.

    Gao, Meiling; Hu, Liangliang; Li, Yuhong; Weng, Yiqun

    2016-10-01

    The cucumber chlorophyll-deficient golden leaf mutation is due to a single nucleotide substitution in the CsChlI gene for magnesium chelatase I subunit which plays important roles in the chlorophyll biosynthesis pathway. The Mg-chelatase catalyzes the insertion of Mg(2+) into the protoporphyrin IX in the chlorophyll biosynthesis pathway, which is a protein complex encompassing three subunits CHLI, CHLD, and CHLH. Chlorophyll-deficient mutations in genes encoding the three subunits have played important roles in understanding the structure, function and regulation of this important enzyme. In an EMS mutagenesis population, we identified a chlorophyll-deficient mutant C528 with golden leaf color throughout its development which was viable and able to set fruits and seeds. Segregation analysis in multiple populations indicated that this leaf color mutation was recessively inherited and the green color showed complete dominance over golden color. Map-based cloning identified CsChlI as the candidate gene for this mutation which encoded the CHLI subunit of cucumber Mg-chelatase. The 1757-bp CsChlI gene had three exons and a single nucleotide change (G to A) in its third exon resulted in an amino acid substitution (G269R) and the golden leaf color in C528. This mutation occurred in the highly conserved nucleotide-binding domain of the CHLI protein in which chlorophyll-deficient mutations have been frequently identified. The mutant phenotype, CsChlI expression pattern and the mutated residue in the CHLI protein suggested the mutant allele in C528 is unique among mutations identified so far in different species. This golden leaf mutant not only has its potential in cucumber breeding, but also provides a useful tool in understanding the CHLI function and its regulation in the chlorophyll biosynthesis pathway as well as chloroplast development.

  6. Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis1[OPEN

    Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E.; Chen, Ming; Zhou, Yongming; Yu, Bin

    2015-01-01

    Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. PMID:26048882

  7. Recent Trends in Global Ocean Chlorophyll

    Gregg, Watson; Casey, Nancy

    2004-01-01

    Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 5% since 1998. The North Pacific ocean basin has increased nearly 19%. To understand the causes of these trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The mode1 utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. Ths enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll.

  8. Evaluation on selected dwarf and semidwarf mutants of upland rice

    Riyanti Sumanggono, A.M.

    1984-01-01

    Seratus malam local upland rice variety was irradiated with gamma-rays at doses of O.1, 0.2, 0.3, 0.4 and 0.5 kGy. Observation of radiation effect was carried out on root and shoot length of M 1 seedlings; plant height, panicle length and number of tiller and seed sterility in M 1 plants. Selection for dwarf and semi-dwarf characteristics were done in M 2 plants, and selected again in M 3 . Observation on radiation effect indicated that 'Seratus Malam' seems to be more resistant than the lowland rice varieties. Increasing doses of radiation caused increasing frequency of chlorophyll mutations as well as chlorophyll mutants. Whereas, selection of dwarf or semi-dwarf in M 2 plants seems that mutant and mutation frequencies decreased as the dose increased. Dose of 0.2 kGy was suitable for selection of dwarf or semi-dwarf plants. Plant height could be influenced by environmental condition. Many of the selected M 2 plants were not really dwarf or semi-dwarf mutants. M 3 evaluation of the selected M 2 plants was really beneficial in the mutant selection. (author)

  9. Promising rice mutants

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1988-01-01

    Two induced mutants namely, Mut NS 1 (tall) and Mut NS 5 (semi-dwarf) derived from rice variety Nizersail were evaluated for various agronomic characters at four locations in Bangladesh. Both the mutants matured about three weeks earlier and yielded significantly higher than the parent variety Nizersail. (author). 3 tabs., 9 refs

  10. Frequency and spectrum of chlorophyll-deficient mutations in rice after treatment with radiation and alkylating agents

    Bhan, A.K.; Kaul, M.L.H.

    1976-01-01

    Three varieties of rice were treated with gamma rays and two alkylating agents EMS and DES, separately and in combinations, with a view to finding out the frequency and spectrum of chlorophyll mutations in relation to the genotype and the nature of the mutagen. Chlorophyll mutation frequency was enhanced with increasing dose but dropped at very high doses (doses that induced over 90% seeding lethality in M 1 ). The fall was attributed to either the increased mutated sector and diplontic selection after exposure to very high doses or relatively high resistance of some of the seeds. Among chlorophyll mutants in M 2 induced by radiations as well as alkylating agents, the albina type formed the majority class. EMS induced a significantly higher proportion of albinas than did gamma rays

  11. Data for iTRAQ-based quantitative proteomics analysis of Brassica napus leaves in response to chlorophyll deficiency

    Pu Chu

    2015-03-01

    Full Text Available The essential pigment chlorophyll (Chl plays important roles in light harvesting and energy transfer during photosynthesis. Here we present the data from a comparative proteomic analysis of chlorophyll-deficient Brassica napus mutant cde1 and its corresponding wild-type using the iTRAQ approach (Pu Chu et al., 2014 [1]. The distribution of length and number of peptides, mass and sequence coverage of proteins identified was calculated, and the repeatability of the replicates was analyzed. A total of 443 differentially expressed proteins were identified in B. napus leaves, including 228 down-accumulated proteins mainly involved in photosynthesis, porphyrin and chlorophyll metabolism, biosynthesis of secondary metabolites, carbon fixation and 215 up-accumulated proteins that enriched in the spliceosome, mRNA surveillance and RNA degradation.

  12. Water-deficit tolerant classification in mutant lines of indica rice

    Suriyan Cha-um

    2012-04-01

    Full Text Available Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control as water deficit sensitive, using Ward's method.

  13. Mutant heterosis in rice

    1987-01-01

    In the variety TKM6 a high yielding semidwarf mutant has been induced. This TKM6 mutant was used in test crosses with a number of other varieties and mutants to examine the extent of heterosis of dwarfs in rice and to select superior crosses. An excerpt of the published data is given. It appears from the backcross of the mutant with its original variety, that an increase in number of productive tillers occurs in the hybrid, leading to a striking grain yield increase, while the semi-dwarf culm length (the main mutant character) reverts to the normal phenotype. In the cross with IR8 on the other hand, there is only a minimal increase in tiller number but a substantial increase in TGW leading to more than 30% yield increase over the better parent

  14. Selection of gamma-ray induced salt tolerant rice mutants by in vitro mutagenesis

    Kim, Dong Sub; Chun, Jae Beom; Lee, Kyung Jun; Kim, Jin Baek; Kim, Sang Hoon; Yun, Song Jong; Kang, Si Yong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-06-15

    The present study had been performed to select the salt tolerant rice mutant lines through an in vivo and in vitro mutagenesis with a gamma-ray. The physiological responses such as MDA and chlorophyll of the selected salt mutant lines were investigated under salt stress. For the selection of the salt tolerant rice mutants by in vitro mutagenesis with gamma-ray, we conducted a second selection procedure with 1,500 mutant lines induced from the original cv. Dongan (wild-type, WT): Ist, selection under a nutrient solution with 171 mM NaCI: 2nd, selection under in vitro conditions. Based on a growth comparison of the entries, out of mutant lines, the putative 2 salt tolerant rice mutant lines, ST-495 and ST-532, were selected. The 2 ST-lines had a lower malonaldehyde (MDA) contents than wild-type (WT) during salt stress. The survival rate of the WT, ST-495 and ST-532 were 36.6%, 70% and 50% in 171 mM NaCI, respectively. The chlorophyll and carotenoid contents were decreased more in a WT plant than the two selected mutant lines. These rice mutant lines will be released for cultivation at the reclaimed land and used as a control plot for genetic research about salt tolerance.

  15. Selection of gamma-ray induced salt tolerant rice mutants by in vitro mutagenesis

    Kim, Dong Sub; Chun, Jae Beom; Lee, Kyung Jun; Kim, Jin Baek; Kim, Sang Hoon; Yun, Song Jong; Kang, Si Yong

    2010-01-01

    The present study had been performed to select the salt tolerant rice mutant lines through an in vivo and in vitro mutagenesis with a gamma-ray. The physiological responses such as MDA and chlorophyll of the selected salt mutant lines were investigated under salt stress. For the selection of the salt tolerant rice mutants by in vitro mutagenesis with gamma-ray, we conducted a second selection procedure with 1,500 mutant lines induced from the original cv. Dongan (wild-type, WT): Ist, selection under a nutrient solution with 171 mM NaCI: 2nd, selection under in vitro conditions. Based on a growth comparison of the entries, out of mutant lines, the putative 2 salt tolerant rice mutant lines, ST-495 and ST-532, were selected. The 2 ST-lines had a lower malonaldehyde (MDA) contents than wild-type (WT) during salt stress. The survival rate of the WT, ST-495 and ST-532 were 36.6%, 70% and 50% in 171 mM NaCI, respectively. The chlorophyll and carotenoid contents were decreased more in a WT plant than the two selected mutant lines. These rice mutant lines will be released for cultivation at the reclaimed land and used as a control plot for genetic research about salt tolerance

  16. Photosynthetic Characteristics of Flag Leaves in Rice White Stripe Mutant 6001 During Senescence Process

    Xiao-hui ZHEN

    2014-11-01

    Full Text Available Physiological, biochemical and electron microscopy analyses were used to investigate the photosynthetic performance of flag leaves in rice white stripe mutant 6001 during the senescence process. Results showed that the chlorophyll content at the heading and milk-ripe stages in rice mutant 6001 were about 34.78% and 3.00% less than those in wild type 6028, respectively. However, the chlorophyll content at the fully-ripe stage in rice mutant 6001 was higher than that in wild type 6028. At the heading stage, the net photosynthetic rate (Pn in rice mutant 6001 was lower than that in wild type 6028. Rice mutant 6001 also exhibited a significantly slower decrease rate of Pn than wild type 6028 during the senescence progress, especially at the later stage. Furthermore, Ca2+-ATPase, Mg2+-ATPase and photophosphorylation activities exhibited the similar trends as the Pn. During the senescence process, the 68 kDa polypeptide concentrations in the thylakoid membrane proteins exhibited a significant change, which was one of the critical factors that contributed to the observed change in photosynthesis. We also observed that the chloroplasts of rice mutant 6001 exhibited higher integrity than those of wild type 6028, and the chloroplast membrane of rice mutant 6001 disintegrated more slow during the senescence process. In general, rice mutant 6001 had a relatively slower senescence rate than wild type 6028, and exhibited anti-senescence properties.

  17. Identification of Genes Associated with Chlorophyll Accumulation in Flower Petals

    Ohmiya, Akemi; Hirashima, Masumi; Yagi, Masafumi; Tanase, Koji; Yamamizo, Chihiro

    2014-01-01

    Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation. PMID:25470367

  18. Afterglow of chlorophyll in vivo and photosynthesis

    Goedheer, J.C.

    1962-01-01

    Two pigment systems are involved in the afterglow of chlorophyll a-containing cells. Absorption in only one of these systems (promoting or “p” system) is effective in producing luminescence. If light is absorbed simultaneously by the other (quenching or “q” system), a decrease in luminescence

  19. SHORT COMMUNICATION ISOLATION OF CHLOROPHYLL A ...

    a

    chromatography (CCC) technique has been applied to the separation of chlorophyll a from ... auxiliary gas flow rate, 0.06 L min-1; ion spray voltage, 3.5 kV; capillary .... This work presents a successful application of column chromatography ...

  20. Overview of remote sensing of chlorophyll flourescene in ocean waters

    Overview of remote sensing of chlorophyll flourescene in ocean waters. ... Besides empirical algorithms with the blue-green ratio, the algorithms based on ... between fluorescence and chlorophyll concentration and the red shift phenomena.

  1. Comprehensive chlorophyll composition in the main edible seaweeds.

    Chen, Kewei; Ríos, José Julián; Pérez-Gálvez, Antonio; Roca, María

    2017-08-01

    Natural chlorophylls present in seaweeds have been studied regarding their biological activities and health benefit effects. However, detailed studies regarding characterization of the complete chlorophyll profile either qualitatively and quantitatively are scarce. This work deals with the comprehensive spectrometric study of the chlorophyll derivatives present in the five main coloured edible seaweeds. The novel complete MS 2 characterization of five chlorophyll derivatives: chlorophyll c 2 , chlorophyll c 1 , purpurin-18 a, pheophytin d and phytyl-purpurin-18 a has allowed to obtain fragmentation patterns associated with their different structural features. New chlorophyll derivatives have been identified and quantified by first time in red, green and brown seaweeds, including some oxidative structures. Quantitative data of the chlorophyll content comes to achieve significant information for food composition databases in bioactive compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Involvement of Arabidopsis glutaredoxin S14 in the maintenance of chlorophyll content.

    Rey, Pascal; Becuwe, Noëlle; Tourrette, Sébastien; Rouhier, Nicolas

    2017-10-01

    Plant class-II glutaredoxins (GRXs) are oxidoreductases carrying a CGFS active site signature and are able to bind iron-sulfur clusters in vitro. In order to explore the physiological functions of the 2 plastidial class-II isoforms, GRXS14 and GRXS16, we generated knockdown and overexpression Arabidopsis thaliana lines and characterized their phenotypes using physiological and biochemical approaches. Plants deficient in one GRX did not display any growth defect, whereas the growth of plants lacking both was slowed. Plants overexpressing GRXS14 exhibited reduced chlorophyll content in control, high-light, and high-salt conditions. However, when exposed to prolonged darkness, plants lacking GRXS14 showed accelerated chlorophyll loss compared to wild-type and overexpression lines. We observed that the GRXS14 abundance and the proportion of reduced form were modified in wild type upon darkness and high salt. The dark treatment also resulted in decreased abundance of proteins involved in the maturation of iron-sulfur proteins. We propose that the phenotype of GRXS14-modified lines results from its participation in the control of chlorophyll content in relation with light and osmotic conditions, possibly through a dual action in regulating the redox status of biosynthetic enzymes and contributing to the biogenesis of iron-sulfur clusters, which are essential cofactors in chlorophyll metabolism. © 2017 John Wiley & Sons Ltd.

  3. Cytochrome P450 CYP89A9 Is Involved in the Formation of Major Chlorophyll Catabolites during Leaf Senescence in Arabidopsis[W][OA

    Christ, Bastien; Süssenbacher, Iris; Moser, Simone; Bichsel, Nicole; Egert, Aurelie; Müller, Thomas; Hörtensteiner, Stefan

    2013-01-01

    Nonfluorescent chlorophyll catabolites (NCCs) were described as products of chlorophyll breakdown in Arabidopsis thaliana. NCCs are formyloxobilin-type catabolites derived from chlorophyll by oxygenolytic opening of the chlorin macrocycle. These linear tetrapyrroles are generated from their fluorescent chlorophyll catabolite (FCC) precursors by a nonenzymatic isomerization inside the vacuole of senescing cells. Here, we identified a group of distinct dioxobilin-type chlorophyll catabolites (DCCs) as the major breakdown products in wild-type Arabidopsis, representing more than 90% of the chlorophyll of green leaves. The molecular constitution of the most abundant nonfluorescent DCC (NDCC), At-NDCC-1, was determined. We further identified cytochrome P450 monooxygenase CYP89A9 as being responsible for NDCC accumulation in wild-type Arabidopsis; cyp89a9 mutants that are deficient in CYP89A9 function were devoid of NDCCs but accumulated proportionally higher amounts of NCCs. CYP89A9 localized outside the chloroplasts, implying that FCCs occurring in the cytosol might be its natural substrate. Using recombinant CYP89A9, we confirm FCC specificity and show that fluorescent DCCs are the products of the CYP89A9 reaction. Fluorescent DCCs, formed by this enzyme, isomerize to the respective NDCCs in weakly acidic medium, as found in vacuoles. We conclude that CYP89A9 is involved in the formation of dioxobilin-type catabolites of chlorophyll in Arabidopsis. PMID:23723324

  4. A review of ocean chlorophyll algorithms and primary production models

    Li, Jingwen; Zhou, Song; Lv, Nan

    2015-12-01

    This paper mainly introduces the five ocean chlorophyll concentration inversion algorithm and 3 main models for computing ocean primary production based on ocean chlorophyll concentration. Through the comparison of five ocean chlorophyll inversion algorithm, sums up the advantages and disadvantages of these algorithm,and briefly analyzes the trend of ocean primary production model.

  5. Physiological validation of photochemical reflectance index (PRI) as a photosynthetic parameter using Arabidopsis thaliana mutants.

    Kohzuma, Kaori; Hikosaka, Kouki

    2018-03-25

    Non-photochemical quenching (NPQ) is the most important photoprotective system in higher plants. NPQ can be divided into several steps according to the timescale of relaxation of chlorophyll fluorescence after reaching a steady state (i.e., the fast phase, qE; middle phase, qZ or qT; and slow phase, qI). The dissipation of excess energy as heat during the xanthophyll cycle, a large component of NPQ, is detectable during the fast to middle phase (sec to min). Although thermal dissipation is primarily investigated using indirect methods such as chlorophyll a fluorescence measurements, such analyses require dark adaptation or the application of a saturating pulse during measurement, making it difficult to continuously monitor this process. Here, we designed an unconventional technique for real-time monitoring of changes in thylakoid lumen pH (as reflected by changes in xanthophyll pigment content) based on the photochemical reflectance index (PRI), which we estimated by measuring light-driven leaf reflectance at 531 nm. We analyzed two Arabidopsis thaliana mutants, npq1 (unable to convert violaxanthin to zeaxanthin due to inhibited violaxanthin de-epoxidase [VDE] activity) and npq4 (lacking PsbS protein), to uncover the regulator of the PRI. The PRI was variable in wild-type and npq4 plants, but not in npq1, indicating that the PRI is related to xanthophyll cycle-dependent thermal energy quenching (qZ) rather than the linear electron transport rate or NPQ. In situ lumen pH substitution using a pH-controlled buffer solution caused a shift in PRI. These results suggest that the PRI reflects only xanthophyll cycle conversion and is therefore a useful parameter for monitoring thylakoid lumen pH (reflecting VDE activity) in vivo. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Energy brands lack vitality

    Godri, S.; Wilders, E.

    2004-01-01

    The three Dutch energy companies (Nuon, Essent and Eneco Energie) have relatively little brand strength. The brands are not perceived to be sufficiently different from one another and are not valued by consumers. With liberalisation imminent, this is hardly a strong starting point. How can you win over consumers if it is not clear what is on offer? In the business market, decision-makers are better placed to distinguish between brands. However, the brands lack vitality in this sector of the market too. The only consolation is that the situation is by no means exclusive to the Netherlands [nl

  7. Direct effect of acid rain on leaf chlorophyll content of terrestrial plants in China.

    Du, Enzai; Dong, Dan; Zeng, Xuetong; Sun, Zhengzhong; Jiang, Xiaofei; de Vries, Wim

    2017-12-15

    Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial plants is lacking. Leaf chlorophyll content is an important indicator of direct foliage damage and strongly related to plant productivity. We synthesized data from published literature on experiments of simulated acid rain, by directly exposing plants to acid solutions with varying pH levels, to assess the direct effect of acid rain on leaf chlorophyll content across 67 terrestrial plants in China. Our results indicate that acid rain substantially reduces leaf chlorophyll content by 6.71% per pH unit across the recorded plant species. The direct reduction of leaf chlorophyll content due to acid rain exposure showed no significant difference across calcicole, ubiquist or calcifuge species, implying that soil acidity preference does not influence the sensitivity to leaf injury by acid rain. On average, the direct effects of acid rain on leaf chlorophyll on trees, shrubs and herbs were comparable. The effects, however varied across functional groups and economic use types. Specifically, leaf chlorophyll content of deciduous species was more sensitive to acid rain in comparison to evergreen species. Moreover, vegetables and fruit trees were more sensitive to acid rain than other economically used plants. Our findings imply a potential production reduction and economic loss due to the direct foliage damage by acid rain. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Phytochrome B Mediates the Regulation of Chlorophyll Biosynthesis through Transcriptional Regulation of ChlH and GUN4 in Rice Seedlings

    Kagawa, Takatoshi; Tanaka, Ayumi; Ueno, Osamu; Shimada, Hiroaki; Takano, Makoto

    2015-01-01

    Accurate regulation of chlorophyll synthesis is crucial for chloroplast formation during the greening process in angiosperms. In this study, we examined the role of phytochrome B (phyB) in the regulation of chlorophyll synthesis in rice seedlings (Oryza sativa L.) through the characterization of a pale-green phenotype observed in the phyB mutant grown under continuous red light (Rc) irradiation. Our results show that the Rc-induced chlorophyll accumulation can be divided into two components—a phyB-dependent and a phyB-independent component, and that the pale-green phenotype is caused by the absence of the phyB-dependent component. To elucidate the role of the missing component we established an Rc-induced greening experiment, the results of which revealed that several genes encoding proteins on the chlorophyll branch were repressed in the phyB mutant. Notable among them were ChlH and GUN4 genes, which encode subunit H and an activating factor of magnesium chelatase (Mg-chelatase), respectively, that were largely repressed in the mutant. Moreover, the kinetic profiles of chlorophyll precursors suggested that Mg-chelatase activity simultaneously decreased with the reduction in the transcript levels of ChlH and GUN4. These results suggest that phyB mediates the regulation of chlorophyll synthesis through transcriptional regulation of these two genes, whose products exert their action at the branching point of the chlorophyll biosynthesis pathway. Reduction of 5-aminolevulinic acid (5-ALA) synthesis could be detected in the mutant, but the kinetic profiles of chlorophyll precursors indicated that it was an event posterior to the reduction of the Mg-chelatase activity. It means that the repression of 5-ALA synthesis should not be a triggering event for the appearance of the pale-green phenotype. Instead, the repression of 5-ALA synthesis might be important for the subsequent stabilization of the pale-green phenotype for preventing excessive accumulation of hazardous

  9. One-electron oxidation of photosynthetic pigments in micelles. Bacteriochlorophyll a, chlorophyll a, chlorophyll b, and pheophytin a

    Chauvet, J.P.

    1981-01-01

    Chlorophyll a, chlorophyll b, and bacteriochlorophyll a in aqueous micellar solutions of Trition X 100 (2%) are readily oxidized by pulse-radiolytically generated N 3 ., Br 2 - ., and (SCN) 2 - . radicals at nearly diffusion-controlled rates. The kinetic study suggests that pigment molecules occupy multiple sites in the micelle. Pheophytin a is only oxidized by N 3 . and Br 2 - . radicals. The absolute spectra and the molar extinction coefficients of chlorophyll a, bacteriochlorophyll a, chlorophyll b, and pheophytin a cations have been determined. The chlorophyll a cation has been observed in the presence of pigment aggregates

  10. Chlorophyllase in Piper betle L. has a role in chlorophyll homeostasis and senescence dependent chlorophyll breakdown.

    Gupta, Supriya; Gupta, Sanjay Mohan; Sane, Aniruddha P; Kumar, Nikhil

    2012-06-01

    Total chlorophyll content and chlorophyllase (chlorophyll-chlorophyllido hydrolase EC 3.1.1.14) activity in fresh leaves of Piper betle L. landrace KS was, respectively, twofold higher and eight fold lower than KV, showing negative correlation between chlorophyll and chlorophyllase activity. Specific chlorophyllase activity was nearly eightfold more in KV than KS. ORF of 918 nt was found in cloned putative chlorophyllase cDNAs from KV and KS. The gene was present as single copy in both the landraces. The encoded polypeptide of 306 amino acids differed only at two positions between the KV and KS; 203 (cysteine to tyrosine) and 301 (glutamine to glycine). Difference in chlorophyllase gene expression between KV and KS was evident in fresh and excised leaves. Up regulation of chlorophyllase gene by ABA and down regulation by BAP was observed in both the landraces; however, there was quantitative difference between KV and KS. Data suggests that chlorophyllase in P. betle is involved in chlorophyll homeostasis and chlorophyll loss during post harvest senescence.

  11. Effect of xanthophyll composition on the chlorophyll excited state lifetime in plant leaves and isolated LHCII

    Johnson, Matthew P.; Zia, Ahmad; Horton, Peter; Ruban, Alexander V.

    2010-01-01

    Xanthophyll excited states have been implicated by transient absorption and two-photon excitation studies in playing a key role in the regulation of photosynthetic light harvesting via photoprotective energy dissipation. For any proposed quenching mechanism to be effective it must reduce the chlorophyll excited state lifetime from 2 ns to ∼0.5-0.4 ns. In the presented study the effect of xanthophyll composition on the chlorophyll excited state lifetime in Arabidopsis leaves in the light harvesting (F m ) and photoprotective (NPQ) states was determined. The data was compared to the chlorophyll excited state lifetime of native isolated LHCII and CP26 in detergent micelles with varying xanthophyll composition. It was found that although the differences in xanthophyll composition between LHC complexes from various Arabidopsis mutants were sufficient to explain the varying F m lifetime (and varying PSII efficiency), they were not of a sufficient scale to fully explain the observed differences in the NPQ lifetimes. Only when the LHC complexes were exposed to a low detergent/low pH media, a condition known to mimic the conformational state of LHCII associated with NPQ in vivo, were variations in excited state lifetime large enough to explain the differences observed in leaves. Furthermore, the data reveal that the replacement of lutein by either zeaxanthin or violaxanthin in the internal xanthophyll binding sites of LHCII and CP26 reduces the efficiency of energy dissipation in the photoprotective state in leaves and isolated complexes.

  12. Revisiting the chlorophyll biosynthesis pathway using genome scale metabolic model of Oryza sativa japonica

    Chatterjee, Ankita; Kundu, Sudip

    2015-01-01

    Chlorophyll is one of the most important pigments present in green plants and rice is one of the major food crops consumed worldwide. We curated the existing genome scale metabolic model (GSM) of rice leaf by incorporating new compartment, reactions and transporters. We used this modified GSM to elucidate how the chlorophyll is synthesized in a leaf through a series of bio-chemical reactions spanned over different organelles using inorganic macronutrients and light energy. We predicted the essential reactions and the associated genes of chlorophyll synthesis and validated against the existing experimental evidences. Further, ammonia is known to be the preferred source of nitrogen in rice paddy fields. The ammonia entering into the plant is assimilated in the root and leaf. The focus of the present work is centered on rice leaf metabolism. We studied the relative importance of ammonia transporters through the chloroplast and the cytosol and their interlink with other intracellular transporters. Ammonia assimilation in the leaves takes place by the enzyme glutamine synthetase (GS) which is present in the cytosol (GS1) and chloroplast (GS2). Our results provided possible explanation why GS2 mutants show normal growth under minimum photorespiration and appear chlorotic when exposed to air. PMID:26443104

  13. Genetic analyses of nonfluorescent root mutants induced by mutagenesis in soybean

    Sawada, S.; Palmer, R.G.

    1987-01-01

    Nonfluorescent root mutants in soybean [Glycine max (L.) Merr.] are useful as markers in genetic studies and in tissue culture research. Our objective was to obtain mutagen-induced nonfluorescent root mutants and to conduct genetic studies with them. Thirteen nonfluorescent mutants were detected among 154016 seedlings derived from soybean lines treated with six mutagens. One of these mutants, derived from Williams treated with 20 kR gamma rays, did not correspond to any of the known (standard) nonfluorescent spontaneous mutants. This is the first mutagen-induced nonfluorescent root mutant in soybean. It was assigned Genetic Type Collection no. T285 and the gene symbol fr5 fr5. The fr5 allele was not located on trisomics A, B, or C and was not linked to five chlorophyll-deficient mutants (y9, y11, y12, y13, and y20-k2) or flower color mutant w1. The remaining nonfluorescent root mutants were at the same loci as known spontaneous mutants; i.e., four had the fr1 allele, five had the fr2 allele, and three had the fr4 allele

  14. Data and Dynamics Driven Approaches for Modelling and Forecasting the Red Sea Chlorophyll

    Dreano, Denis

    2017-05-31

    Phytoplankton is at the basis of the marine food chain and therefore play a fundamental role in the ocean ecosystem. However, the large-scale phytoplankton dynamics of the Red Sea are not well understood yet, mainly due to the lack of historical in situ measurements. As a result, our knowledge in this area relies mostly on remotely-sensed observations and large-scale numerical marine ecosystem models. Models are very useful to identify the mechanisms driving the variations in chlorophyll concentration and have practical applications for fisheries operation and harmful algae blooms monitoring. Modelling approaches can be divided between physics- driven (dynamical) approaches, and data-driven (statistical) approaches. Dynamical models are based on a set of differential equations representing the transfer of energy and matter between different subsets of the biota, whereas statistical models identify relationships between variables based on statistical relations within the available data. The goal of this thesis is to develop, implement and test novel dynamical and statistical modelling approaches for studying and forecasting the variability of chlorophyll concentration in the Red Sea. These new models are evaluated in term of their ability to efficiently forecast and explain the regional chlorophyll variability. We also propose innovative synergistic strategies to combine data- and physics-driven approaches to further enhance chlorophyll forecasting capabilities and efficiency.

  15. Productive mutants of niger

    Misra, R.C.

    2001-01-01

    Seeds of six niger (Guizotia abyssinica Cass.) varieties ('GA-10', 'ONS-8', 'IGP-72', 'N-71', 'NB-9' and 'UN-4') were treated with 0.5, 0.75 and 1% ethyl methanesulphonate. After four generations of selection, 29 mutant lines were developed and those were evaluated from 1990-92 during Kharif (July to October) and Rabi (December to March) seasons. Average plant characteristics and yield data of four high yielding mutants along with 'IGP-76' (National Check), GA-10 (Zonal Check) and 'Semiliguda Local' (Local Check) are presented

  16. Biosynthetic pathways to delta-aminolevulinic acid induced by blue light in the pigment mutant C-2A' of Scenedesmus obliquus

    Klein, O.; Senger, H.

    1978-01-01

    The X-ray induced mutant C-2A' of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, delta-aminolevulinic acid (ALA) is synthesized and chlorophyll is formed. These processes are blue light dependent and ceased immediately when the cells were transferred back into darkness. Addition of levulinic acid (LA) inhibited the light-dependent formation of chlorophyll and caused accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled 14 C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominated over the glutamate pathway, but both led to chlorophyll formation. (author)

  17. Tolerance of some Potato Mutants Induced with Gamma Irradiation to Drought in Vitro

    Al-Safadi, B.; Al-Ayyoubi, Z.

    2007-01-01

    An in vitro selection program was conducted in order to improve potato (Solanum tuberosum,L.) tolerance to drought. Potato mutant plants were obtained through a previously conducted mutation breeding program on three potato cultivars (Draga, Spunta, and Diamant) aimed to improve potato tolerance to salinity and resistance to late blight disease. In order to apply selection pressure, growth media (MS based) were prepared with the addition of 1%, 2%, 3% concentrations of Poly Ethylene Glycol (PEG). As a result, three mutants were selected that were tolerant to water stress (i.e. drought tolerant), two of them were derived from the cultivar Draga and one came from Spunta. Physiological growth parameters (plant length, leaf number, branch number, roots number, leaf area, stomata number, and chlorophyll concentration content) were determined on the growing plantlets. The selected mutants were distinguished based on some characteristics which being associated with in their tolerance to drought. Such as an increases in leaf number, root number, and a decrease in stomata number. However a reduction in chlorophyll content was observed as compared with the control. This is considered a negative parameter which may result in a decrease in number and size of tubers. Thus it is important to continue selection for higher chlorophyll content. Also, these mutant lines will need further selection in the field for plants with larger tubers before they can be considered as certified lines.

  18. Phenotyping of Arabidopsis Drought Stress Response Using Kinetic Chlorophyll Fluorescence and Multicolor Fluorescence Imaging

    Jieni Yao

    2018-05-01

    Full Text Available Plant responses to drought stress are complex due to various mechanisms of drought avoidance and tolerance to maintain growth. Traditional plant phenotyping methods are labor-intensive, time-consuming, and subjective. Plant phenotyping by integrating kinetic chlorophyll fluorescence with multicolor fluorescence imaging can acquire plant morphological, physiological, and pathological traits related to photosynthesis as well as its secondary metabolites, which will provide a new means to promote the progress of breeding for drought tolerant accessions and gain economic benefit for global agriculture production. Combination of kinetic chlorophyll fluorescence and multicolor fluorescence imaging proved to be efficient for the early detection of drought stress responses in the Arabidopsis ecotype Col-0 and one of its most affected mutants called reduced hyperosmolality-induced [Ca2+]i increase 1. Kinetic chlorophyll fluorescence curves were useful for understanding the drought tolerance mechanism of Arabidopsis. Conventional fluorescence parameters provided qualitative information related to drought stress responses in different genotypes, and the corresponding images showed spatial heterogeneities of drought stress responses within the leaf and the canopy levels. Fluorescence parameters selected by sequential forward selection presented high correlations with physiological traits but not morphological traits. The optimal fluorescence traits combined with the support vector machine resulted in good classification accuracies of 93.3 and 99.1% for classifying the control plants from the drought-stressed ones with 3 and 7 days treatments, respectively. The results demonstrated that the combination of kinetic chlorophyll fluorescence and multicolor fluorescence imaging with the machine learning technique was capable of providing comprehensive information of drought stress effects on the photosynthesis and the secondary metabolisms. It is a promising

  19. Search for C4 developmental mutants in Panicum maximum Jacq

    Fladung, M.

    2001-01-01

    small leaves and reached a total plant height of maximal 0.6 meter. In leaf sections, it was characterized by an almost lack of the small veins surrounded by four bundle sheath cells. The leaf lamina of the variant abs showed several alterations, including doublets of veins, veins without bundle sheath, additional bundle sheath cells outside the veins or large bundle sheath cells participating in two bundle sheaths. Also the distribution of phloem and xylem cells within the bundles were quite altered in the variant compared to the wildtype. The leaves were greener, with a higher than normal chlorophyll content and with longitudinal veins not perfectly straight but following a wavy path on the leaf lamina. Compared with wild type plants the phenotype of the mbl mutant was less erect and had pending leaves because of the absence of the main midrib. In wild type leaves the midrib was represented by an enlargement of the mesophyll parenchyma which included parenchymatous and sclerenchymatous cells. This structure was absent in mutant leaves, only small irregular files of parenchymatous cells were present at the base of the leaf lamina. The florets of this mutant had no carpel but one or two additional stamen. The variant var1 had a variegated phenotype with stripes of yellow-green and white tissues alternating the leaf laminae. In yellow-green sectors the chloroplasts were absent only in bundle sheath cells, which supports the hypothesis of different ways of development of bundle sheath and mesophyll cell chloroplasts. The adjacent mesophyll cells were less pigmented than similar ones present in non-variant sectors. In white sectors, the chloroplasts were absent both in bundle sheath and mesophyll cells. The variant was partially fertile. Seed germination was 30 to 40%, and despite the unknown portion of apomictic seeds, 65 produced white, 20 green and 34 variegated seedlings out of a sample of 119 germinated seeds. Analysis of segregation of these green and variegated

  20. Salt stress change chlorophyll fluorescence in mango

    Cicero Cartaxo de Lucena

    2012-12-01

    Full Text Available This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs/(Fm'], D = (1- Fv'/Fm' and ETR = (ΦPSII×PPF×0,84×0,5 were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.

  1. An extended PROSPECT: Advance in the leaf optical properties model separating total chlorophylls into chlorophyll a and b.

    Zhang, Yao; Huang, Jingfeng; Wang, Fumin; Blackburn, George Alan; Zhang, Hankui K; Wang, Xiuzhen; Wei, Chuanwen; Zhang, Kangyu; Wei, Chen

    2017-07-25

    The PROSPECT leaf optical model has, to date, well-separated the effects of total chlorophyll and carotenoids on leaf reflectance and transmittance in the 400-800 nm. Considering variations in chlorophyll a:b ratio with leaf age and physiological stress, a further separation of total plant-based chlorophylls into chlorophyll a and chlorophyll b is necessary for advanced monitoring of plant growth. In this study, we present an extended version of PROSPECT model (hereafter referred to as PROSPECT-MP) that can combine the effects of chlorophyll a, chlorophyll b and carotenoids on leaf directional hemispherical reflectance and transmittance (DHR and DHT) in the 400-800 nm. The LOPEX93 dataset was used to evaluate the capabilities of PROSPECT-MP for spectra modelling and pigment retrieval. The results show that PROSPECT-MP can both simultaneously retrieve leaf chlorophyll a and b, and also performs better than PROSPECT-5 in retrieving carotenoids concentrations. As for the simulation of DHR and DHT, the performances of PROSPECT-MP are similar to that of PROSPECT-5. This study demonstrates the potential of PROSPECT-MP for improving capabilities of remote sensing of leaf photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) and for providing a framework for future refinements in the modelling of leaf optical properties.

  2. The Use of a Chlorophyll Meter (SPAD-502) for Field Determinations of Red Mangrove (Rhizophora Mangle L.) Leaf Chlorophyll Amount

    Connelly, Xana M.

    1997-01-01

    The red mangrove Rhizophora mangle L., is a halophytic woody spermatophyte common to the land-sea interface of tropical and subtropical intertidal zones. It has been reported that 60 to 75% of the coastline of the earth's tropical regions are lined with mangroves. Mangroves help prevent shoreline erosion, provide breeding, nesting and feeding areas for many marine animals and birds. Mangroves are important contributors of primary production in the coastal environment, and this is largely proportional to the standing crop of leaf chlorophylls. Higher intensities of ultraviolet radiation, resulting from stratospheric ozone depletion, can lead to a reduction of chlorophyll in terrestrial plants. Since the most common method for determining chlorophyll concentration is by extraction and this is labor intensive and time consuming, few studies on photosynthetic pigments of mangroves have been reported. Chlorophyll meter readings have been related to leaf chlorophyll content in apples and maples. It has also been correlated to nitrogen status in corn and cotton. Peterson et al., (1993) used a chlorophyll meter to detect nitrogen deficiency in crops and in determining the need for additional nitrogen fertilizer. Efforts to correlate chlorophyll meter measurements to chlorophyll content of mangroves have not been reported. This paper describes the use of a hand-held chlorophyll meter (Minolta SPAD-502) to determine the amount of red mangrove foliar chlorophyll present in the field.

  3. The Magnesium Chelation Step in Chlorophyll Biosynthesis

    Gregory L. Dilworth, Ph.D Chemical Sciences, Geosciences and Biosciences Division Office of Basis Energy Sciences, greg.dilworth@science.doe.gov

    2001-01-17

    The progress described in this report encompasses work supported by DOE grant DE-FG09-89ER13989 for the period 2/15/92 to the present 6/14/94. The goals of the project were to continue investigating the enzymology of Mg-chelatase and to investigate the co-regulation of heme and chlorophyll formation in intact plastids. During this period the laboratory had additional support (two years) from USDA to investigate heme metabolism in chloroplasts. This report is arranged so that the progress is described by reference to manuscripts which are published, under review or in preparation.

  4. Lil3 dimerization and chlorophyll binding in Arabidopsis thaliana.

    Mork-Jansson, Astrid Elisabeth; Gargano, Daniela; Kmiec, Karol; Furnes, Clemens; Shevela, Dmitriy; Eichacker, Lutz Andreas

    2015-10-07

    The two-helix light harvesting like (Lil) protein Lil3 belongs to the family of chlorophyll binding light harvesting proteins of photosynthetic membranes. A function in tetrapyrrol synthesis and stabilization of geranylgeraniol reductase has been shown. Lil proteins contain the chlorophyll a/b-binding motif; however, binding of chlorophyll has not been demonstrated. We find that Lil3.2 from Arabidopsis thaliana forms heterodimers with Lil3.1 and binds chlorophyll. Lil3.2 heterodimerization (25±7.8 nM) is favored relative to homodimerization (431±59 nM). Interaction of Lil3.2 with chlorophyll a (231±49 nM) suggests that heterodimerization precedes binding of chlorophyll in Arabidopsis thaliana. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  5. Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

    Kromkamp, J.C.; Morris, E.P.; Forster, R.M.; Honeywill, C.; Hagerthey, S.; Paterson, D.M.

    2006-01-01

    Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two

  6. Chlorophyll-a specific volume scattering function of phytoplankton.

    Tan, Hiroyuki; Oishi, Tomohiko; Tanaka, Akihiko; Doerffer, Roland; Tan, Yasuhiro

    2017-06-12

    Chlorophyll-a specific light volume scattering functions (VSFs) by cultured phytoplankton in visible spectrum range is presented. Chlorophyll-a specific VSFs were determined based on the linear least squares method using a measured VSFs with different chlorophyll-a concentrations. We found obvious variability of it in terms of spectral and angular shapes of VSF between cultures. It was also presented that chlorophyll-a specific scattering significantly affected on spectral variation of the remote sensing reflectance, depending on spectral shape of b. This result is useful for developing an advance algorithm of ocean color remote sensing and for deep understanding of light in the sea.

  7. Stereoelectronic properties of aggregated chlorophyll systems

    Christoffersen, R. E.; Maggiora, G. M.

    1979-09-01

    During the first nine months of the current contract, significant progress has occurred in several areas. All SCF CI studies of the singlet and triplet states of the neutral molecules Et-Chl a, Et-Pheo a, Et-BChl a, and Et-BPheo a, and the doublet states of the ..pi..-cation radicals Et-Chl a/sup +/. and Et-BChl a/sup +/. have now been completed. In addition, SCF CI calculations on BPheo a/sup -/. indicate that ..pi..-anion radicals can also be studied using the present approach. Similar work on a number of other ..pi..-cation and ..pi..-anion radicals is currently underway. Preliminary SCF CI studies have also been completed for benzoquinone and dihydroquinone, and studies on benzoquinone/sup -/. should be completed by the end of this year. The development and characterization of an empirical potential function is nearly complete, and data from selected systems is summarized. Implementation of a more efficient, quadratically convergent energy minimization procedure is also being carried out. This procedure should make it possible to study the geometry and properties of dimeric chlorophyll systems as well as various ligand-chlorophyll systems. Developmental work is continuing on the direct calculation of optical rotatory strengths.

  8. Biosynthesis of Chlorophyll a in a Purple Bacterial Phototroph and Assembly into a Plant Chlorophyll-Protein Complex.

    Hitchcock, Andrew; Jackson, Philip J; Chidgey, Jack W; Dickman, Mark J; Hunter, C Neil; Canniffe, Daniel P

    2016-09-16

    Improvements to photosynthetic efficiency could be achieved by manipulating pigment biosynthetic pathways of photosynthetic organisms in order to increase the spectral coverage for light absorption. The development of organisms that can produce both bacteriochlorophylls and chlorophylls is one way to achieve this aim, and accordingly we have engineered the bacteriochlorophyll-utilizing anoxygenic phototroph Rhodobacter sphaeroides to make chlorophyll a. Bacteriochlorophyll and chlorophyll share a common biosynthetic pathway up to the precursor chlorophyllide. Deletion of genes responsible for the bacteriochlorophyll-specific modifications of chlorophyllide and replacement of the native bacteriochlorophyll synthase with a cyanobacterial chlorophyll synthase resulted in the production of chlorophyll a. This pigment could be assembled in vivo into the plant water-soluble chlorophyll protein, heterologously produced in Rhodobacter sphaeroides, which represents a proof-of-principle for the engineering of novel antenna complexes that enhance the spectral range of photosynthesis.

  9. Connexin mutants and cataracts

    Eric C Beyer

    2013-04-01

    Full Text Available The lens is a multicellular, but avascular tissue that must stay transparent to allow normal transmission of light and focusing of it on the retina. Damage to lens cells and/or proteins can cause cataracts, opacities that disrupt these processes. The normal survival of the lens is facilitated by an extensive network of gap junctions formed predominantly of connexin46 and connexin50. Mutations of the genes that encode these connexins (GJA3 and GJA8 have been identified and linked to inheritance of cataracts in human families and mouse lines. In vitro expression studies of several of these mutants have shown that they exhibit abnormalities that may lead to disease. Many of the mutants reduce or modify intercellular communication due to channel alterations (including loss of function or altered gating or due to impaired cellular trafficking which reduces the number of gap junction channels within the plasma membrane. However, the abnormalities detected in studies of other mutants suggest that they cause cataracts through other mechanisms including gain of hemichannel function (leading to cell injury and death and formation of cytoplasmic accumulations (that may act as light scattering particles. These observations and the anticipated results of ongoing studies should elucidate the mechanisms of cataract development due to mutations of lens connexins and abnormalities of other lens proteins. They may also contribute to our understanding of the mechanisms of disease due to connexin mutations in other tissues.

  10. Revisiting chlorophyll extraction methods in biological soil crusts - methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

    Caesar, Jennifer; Tamm, Alexandra; Ruckteschler, Nina; Lena Leifke, Anna; Weber, Bettina

    2018-03-01

    Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO) as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

  11. Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

    J. Caesar

    2018-03-01

    Full Text Available Chlorophyll concentrations of biological soil crust (biocrust samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual. Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

  12. A new three-band algorithm for estimating chlorophyll concentrations in turbid inland lakes

    Duan Hongtao; Ma Ronghua; Zhao Chenlu; Zhou Lin; Shang Linlin; Zhang Yuanzhi; Loiselle, Steven Arthur; Xu Jingping

    2010-01-01

    A new three-band model was developed to estimate chlorophyll-a concentrations in turbid inland waters. This model makes a number of important improvements with respect to the three-band model commonly used, including lower restrictions on wavelength optimization and the use of coefficients which represent specific inherent optical properties. Results showed that the new model provides a significantly higher determination coefficient and lower root mean squared error (RMSE) with respect to the original model for upwelling data from Taihu Lake, China. The new model was tested using simulated data for the MERIS and GOCI satellite systems, showing high correlations with the former and poorer correlations with the latter, principally due to the lack of a 709 nm centered waveband. The new model provides numerous advantages, making it a suitable alternative for chlorophyll-a estimations in turbid and eutrophic waters.

  13. The different phenotypes of phot- photosynthetic deficient mutants in Euglena gracilis: the frequency of production by ultraviolet irradiation

    Nicolas, Paul; Heizmann, Philippe; Nigon, Victor

    1982-01-01

    In Euglena gracilis, pigment-less mutants appear spontaneously with a frequency of about 2-5x10 -3 . Ultraviolet-irradiation increases the proportion of chlorophyll-less colonies to an upper limit where green colonies represent 4x10 -4 of the surviving ones. This limit might indicate the occurrence of processes involving repair of the chloroplastic DNA. Most of the photosynthetic-deficient (phot - ) mutants induced by ultraviolet irradiation are characterized by the presence of a reduced number of chloroplast DNA molecules showing deletions (phi - class). Most of the phi - mutants present the phenotype phi - chlo - car - , where neither chlorophyll nor carotenoids are obvious: the phi - chlo - car + mutants, devoid of chlorophyll but containing carotenoids, are obtained among the phi - strains with a frequency lower than 10 -3 . The phot - mutants which belong to the cp - class are characterized by the maintenance of a great number of chloroplastic DNA molecules, where large deletions are absent: their occurrence after ultraviolet irradiation is low [fr

  14. An optimal thermal condition for maximal chlorophyll extraction

    Fu Jia-Jia

    2017-01-01

    Full Text Available This work describes an environmentally friendly process for chlorophyll extraction from bamboo leaves. Shaking water bath and ultrasound cleaner are adopted in this technology, and the influence of temperature of the water bath and ultrasonic cleaner is evaluated. Results indicated that there is an optimal condition for maximal yield of chlorophyll.

  15. Regional ocean-colour chlorophyll algorithms for the Red Sea

    Brewin, Robert J.W.; Raitsos, Dionysios E.; Dall'Olmo, Giorgio; Zarokanellos, Nikolaos; Jackson, Thomas; Racault, Marie-Fanny; Boss, Emmanuel S.; Sathyendranath, Shubha; Jones, Burton; Hoteit, Ibrahim

    2015-01-01

    an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll

  16. Chlorophyll in tomato seeds: marker for seed performance?

    Suhartanto, M.R.

    2002-01-01

    Using Xe-PAM, laser induced fluorometry and high performance liquid chromatography we found that chlorophyll was present in young tomato (cv. Moneymaker) seeds and was degraded during maturation. Fluorescence microscopy and imaging showed that the majority of chlorophyll is located in the

  17. A model for chlorophyll fluorescence and photosynthesis at leaf scale

    Tol, van der C.; Verhoef, W.; Rosema, A.

    2009-01-01

    This paper presents a leaf biochemical model for steady-state chlorophyll fluorescence and photosynthesis of C3 and C4 vegetation. The model is a tool to study the relationship between passively measured steady-state chlorophyll fluorescence and actual photosynthesis, and its evolution during the

  18. Chlorophyll meter reading and total nitrogen content applied as ...

    Ana Mascarello

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content ... devices to measure chlorophyll index (SPAD) and N content in the leaf. The nitrogen levels were found ... absorption of other nutrients and the production of carbohydrates. The methods ...

  19. Dinitrogen fixation in a unicellular chlorophyll d-containing cyanobacterium

    Pfreundt, U.; Stal, L.J.; Voss, B.; Hess, W.R.

    2012-01-01

    Marine cyanobacteria of the genus Acaryochloris are the only known organisms that use chlorophyll d as a photosynthetic pigment. However, based on chemical sediment analyses, chlorophyll d has been recognized to be widespread in oceanic and lacustrine environments. Therefore it is highly relevant to

  20. The stem and leaf super green mutant induced by 60Co γ-rays irradiation

    Wei Yubo; Liang Naiting; Buhaliqiem; Zhang Yinbao

    2003-01-01

    Super green gene mutant was developed from population of M 2 generation after the dry seeds of rice Huazhiwu from Japan with good quality and resistance to cold had been irradiated with 50 Gy 60 Co γ-ray. The leaf, sheath, panicle axis and petiole of mutant was characterized by deeply green, and did not turn yellow after maturing date. The chlorophyll content in straw is 2.2 times higher than that in common straw. The results of raising livestock showed that horse, donkey and sheep had evident selectivity to the green straw

  1. Influence of ambient sulphur dioxide on chlorophyll

    Shahare, C.B.; Varshney, C.K.

    1995-01-01

    For the evaluation of the injury due to SO 2 from Indraprashtha (IP) Thermal Power Plant, eight species of trees were selected. Experiment was divided in two sections. Section one include transplanted tree saplings of Bauhinia variegata, Delonix regia, Flcus benghalensis, Putranjiwa roxburghii, Morus indica, Polyalthia longifolia, Leucaena leucocephala and Tabernaemontana coronaria. Here one set of plants was transplanted to polluted site of IP and other set was maintained at non polluted site of Jawaharlal Nehru University (Ecological Nursery). Second section of the study have naturally growing trees of the same species in the vicinity of the transplanted plants. Findings of the present study show that tree species were not safe at polluted site. Maximum chlorophyll reduction occurred in Bauhinia variegata, that is 32.05% (transplanted saplings). In naturally growing trees up to 35.70% reduction was seen in B. variegata. (author). 11 refs., 2 tabs

  2. Phytohormone and Light Regulation of Chlorophyll Degradation

    Xiaoyu Zhu

    2017-11-01

    Full Text Available Degreening, due to the net loss of chlorophyll (Chl, is the most prominent symptom during the processes of leaf senescence, fruit ripening, and seed maturation. Over the last decade or so, extensive identifications of Chl catabolic genes (CCGs have led to the revelation of the biochemical pathway of Chl degradation. As such, exploration of the regulatory mechanism of the degreening process is greatly facilitated. During the past few years, substantial progress has been made in elucidating the regulation of Chl degradation, particularly via the mediation of major phytohormones' signaling. Intriguingly, ethylene and abscisic acid's signaling have been demonstrated to interweave with light signaling in mediating the regulation of Chl degradation. In this review, we briefly summarize this progress, with an effort on providing a framework for further investigation of multifaceted and hierarchical regulations of Chl degradation.

  3. The magnesium chelation step in chlorophyll biosynthesis

    Weinstein, J.

    1990-11-01

    In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

  4. Calibrations between chlorophyll meter values and chlorophyll contents vary as the result of differences in leaf structure

    In order to relate leaf chlorophyll meter values with total leaf chlorophyll contents (µg cm-2), calibration equations are established with measured data on leaves. Many studies have documented differences in calibration equations using different species and using different growing conditions for th...

  5. Staying green postharvest: how three mutations in the Arabidopsis chlorophyll b reductase gene NYC1 delay degreening by distinct mechanisms.

    Jibran, Rubina; Sullivan, Kerry L; Crowhurst, Ross; Erridge, Zoe A; Chagné, David; McLachlan, Andrew R G; Brummell, David A; Dijkwel, Paul P; Hunter, Donald A

    2015-11-01

    Stresses such as energy deprivation, wounding and water-supply disruption often contribute to rapid deterioration of harvested tissues. To uncover the genetic regulation behind such stresses, a simple assessment system was used to detect senescence mutants in conjunction with two rapid mapping techniques to identify the causal mutations. To demonstrate the power of this approach, immature inflorescences of Arabidopsis plants that contained ethyl methanesulfonate-induced lesions were detached and screened for altered timing of dark-induced senescence. Numerous mutant lines displaying accelerated or delayed timing of senescence relative to wild type were discovered. The underlying mutations in three of these were identified using High Resolution Melting analysis to map to a chromosomal arm followed by a whole-genome sequencing-based mapping method, termed 'Needle in the K-Stack', to identify the causal lesions. All three mutations were single base pair changes and occurred in the same gene, NON-YELLOW COLORING1 (NYC1), a chlorophyll b reductase of the short-chain dehydrogenase/reductase (SDR) superfamily. This was consistent with the mutants preferentially retaining chlorophyll b, although substantial amounts of chlorophyll b were still lost. The single base pair mutations disrupted NYC1 function by three distinct mechanisms, one by producing a termination codon, the second by interfering with correct intron splicing and the third by replacing a highly conserved proline with a non-equivalent serine residue. This non-synonymous amino acid change, which occurred in the NADPH binding domain of NYC1, is the first example of such a mutation in an SDR protein inhibiting a physiological response in plants. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. Photorepair mutants of Arabidopsis

    Jiang, C.Z.; Yee, J.; Mitchell, D.L.; Britt, A.B.

    1997-01-01

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  7. Construindo Marcas Mutantes

    Elizete De Azevedo Kreutz

    2012-09-01

    Full Text Available O presente artigo é o resultado de estudos realizados desde 2000 e busca instrumentalizar os proñssionals para a construção de Marcas Mutantes, que é   uma tendência contemporânea nas estratégias comunicacionais e de branding. Embora esta estratégia ainda não esteja consolidada, observamos que a mesma tem obtido um crescimento constante e tem sido adotadas pelas mais diferentes categorias de marcas e não apenas por aquelas direcionadas aos jovens, ao esporte, ao entretenimento, como era no principia. Com base na Hermenêutica de Profundidade de Thompson (1995, alicerçada nas pesquisas bibliográficas, de intemet, entrevistas e análise semiótica, desenhamos um método de construção de Marcas Mutantes dividido em sete fases. Como resultado, esperamos que este estudo possa auxiliar na compreensão dos processos envolvidos, ao mesmo tempo que provoque a discussão sobreo mesmo e, por consequência, o seu aprimoramento.

  8. Stress-tolerant mutants induced by heavy-ion beams

    Abe, Tomoko; Yoshida, Shigeo [Institute of Physical and Chemical Research, Wako, Saitama (Japan); Bae, Chang-Hyu [Sunchon National University, Sunchon (Korea); Ozaki, Takuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Wang, Jing Ming [Akita Prefectural Univ. (Japan)

    2000-07-01

    Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M{sub 1} seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M{sub 3} progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to {sup 14}N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M{sub 1} progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M{sub 1} seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

  9. Stress-tolerant mutants induced by heavy-ion beams

    Abe, Tomoko; Yoshida, Shigeo; Bae, Chang-Hyu; Ozaki, Takuo

    2000-01-01

    Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M 1 seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M 3 progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to 14 N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M 1 progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M 1 seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

  10. Mutant E. coli strain with increased succinic acid production

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    2001-09-25

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which has been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  11. Mutant E. coli strain with increased succinic acid production

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1998-01-01

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which as been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  12. Optical Method for Estimating the Chlorophyll Contents in Plant Leaves.

    Pérez-Patricio, Madaín; Camas-Anzueto, Jorge Luis; Sanchez-Alegría, Avisaí; Aguilar-González, Abiel; Gutiérrez-Miceli, Federico; Escobar-Gómez, Elías; Voisin, Yvon; Rios-Rojas, Carlos; Grajales-Coutiño, Ruben

    2018-02-22

    This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance), a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD) meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica , Canavalia ensiforme , and Lycopersicon esculentum . Experimental results showed that-in terms of accuracy and processing speed-the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica , where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap.

  13. Effects of biocides on chlorophyll contents of detached basil leaves

    Titima Arunrangsi

    2013-06-01

    Full Text Available Herbicides and insecticides have been widely and intensively used in agricultural areas worldwide to enhance crop yield. However, many biocides cause serious environmental problems. In addition, the biocides may also have some effects on the treated agricultural crops. To study effects of biocides on chlorophyll content in detached basil leaves, 2,4-D dimethylamine salt (2,4 D-Amine, paraquat, carbosulfan, and azadirachtin, were chosen as representatives of biocide. After applying the chemicals to detached basil leaves overnight in darkness, chlorophyll contents were determined. Only treatment with 2,4 D-Amine resulted in reduction of chlorophyll contents significantly compared to treatment with deionized (DI water. In the case of paraquat and carbosulfan, chlorophyll contents were not significantly changed, while slightly higher chlorophyll contents, compared to DI water, after the treatment with azadirachtin, were observed. The results indicated that 2,4 D-Amine shows an ability to accelerate chlorophyll degradation, but azadirachtin helps to retard chlorophyll degradation, when each biocide is used at the concentration recommended by the manufacturer.

  14. Optical Method for Estimating the Chlorophyll Contents in Plant Leaves

    Madaín Pérez-Patricio

    2018-02-01

    Full Text Available This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance, a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica, Canavalia ensiforme, and Lycopersicon esculentum. Experimental results showed that—in terms of accuracy and processing speed—the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica, where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap.

  15. Phenotypic characterization and inheritance of two foliar mutants in pea (Pisum Sativum L.): 'Reduced leaf size' and 'Orange leaf'

    Naidenova, N.; Vassilevska-Ivanova, R.; Tcekova, Z.

    2003-01-01

    Two foliar pea (Pisum sativum L.) mutants characterized by reduced leaf size (2/978) and orange leaf (2/1409 M) were established. Both mutants were described morphologically and their productivity potential , pollen viability and inheritance of the mutant traits were evaluated. The mutant 2/978 was identified after irradiation of dry seeds from cv Borek with 15 Gy fast neutrons and was related to the leaf mutation 'rogue'. Reciprocal crosses between mutant 2/978 and cv Borel were executed, and F 1 and F 2 generations were analyzed. The altered leaf trait was presented in all F 1 plants suggesting a dominant character. F 2 segregation data indicated that the trait was controlled by a single dominant gene. The mutant 2/1409M originated from the mutant 2/978 after irradiation with 50 Gy γ-rays. The main mutant's phenotypic characteristic was the orange-yellow coloration of leaves and plants. After of series of crosses it was established that induced chlorophyll mutation is monogenic, recessive and both mutant traits are independently inherited. Two mutants could be used as appropriate plant material for genetic and biological investigations

  16. Regional ocean-colour chlorophyll algorithms for the Red Sea

    Brewin, Robert J.W.

    2015-05-18

    The Red Sea is a semi-enclosed tropical marine ecosystem that stretches from the Gulf of Suez and Gulf of Aqaba in the north, to the Gulf of Aden in the south. Despite its ecological and economic importance, its biological environment is relatively unexplored. Satellite ocean-colour estimates of chlorophyll concentration (an index of phytoplankton biomass) offer an observational platform to monitor the health of the Red Sea. However, little is known about the optical properties of the region. In this paper, we investigate the optical properties of the Red Sea in the context of satellite ocean-colour estimates of chlorophyll concentration. Making use of a new merged ocean-colour product, from the European Space Agency (ESA) Climate Change Initiative, and in situ data in the region, we test the performance of a series of ocean-colour chlorophyll algorithms. We find that standard algorithms systematically overestimate chlorophyll when compared with the in situ data. To investigate this bias we develop an ocean-colour model for the Red Sea, parameterised to data collected during the Tara Oceans expedition, that estimates remote-sensing reflectance as a function of chlorophyll concentration. We used the Red Sea model to tune the standard chlorophyll algorithms and the overestimation in chlorophyll originally observed was corrected. Results suggest that the overestimation was likely due to an excess of CDOM absorption per unit chlorophyll in the Red Sea when compared with average global conditions. However, we recognise that additional information is required to test the influence of other potential sources of the overestimation, such as aeolian dust, and we discuss uncertainties in the datasets used. We present a series of regional chlorophyll algorithms for the Red Sea, designed for a suite of ocean-colour sensors, that may be used for further testing.

  17. AFM images of complexes between amylose and Aspergillus niger glucoamylase mutants, native and mutant starch binding domains: a model for the action of glucoamylase

    Morris, V. M.; Gunning, A. P.; Faults, C. B.

    2005-01-01

    Atomic force microscopy has been used to investigate the complexes formed between high molecular weight amylose chains and Aspergillus niger glucoamylase mutants (E400Q and W52F), wild-type A. niger starch binding domains (SBDS), and mutant SBDs (W563K and W590K) lacking either of the two starch...

  18. Isozyme differences in barley mutants

    AI-Jibouri, A A.M.; Dham, K M [Department of Botany, Nuclear Research Centre, Baghdad (Iraq)

    1990-01-01

    Full text: Thirty mutants (M{sub 11}) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  19. Isozyme differences in barley mutants

    AI-Jibouri, A.A.M.; Dham, K.M.

    1990-01-01

    Full text: Thirty mutants (M 11 ) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  20. Chlorophyll derivatives for pest and disease control: Are they safe?

    Azizullah, Azizullah; Murad, Waheed

    2015-01-01

    Chlorophyll derivatives are getting widespread acceptance among the researchers as natural photosensitizers for photodynamic control of pests and disease vectors; however, rare attention has been given to evaluation of their toxicity to non-target organisms in the environment. This perspective article highlights that chlorophyll derivatives may not be as safe as believed and can possibly pose risk to non-target organisms in the environment. We invite the attention of environmental biologists, particularly ecotoxicologists, to contribute their role in making the application of chlorophyll derivatives more environmentally friendly and publicly acceptable

  1. Chlorophyll derivatives for pest and disease control: Are they safe?

    Azizullah, Azizullah, E-mail: azizswabi@gmail.com; Murad, Waheed

    2015-01-15

    Chlorophyll derivatives are getting widespread acceptance among the researchers as natural photosensitizers for photodynamic control of pests and disease vectors; however, rare attention has been given to evaluation of their toxicity to non-target organisms in the environment. This perspective article highlights that chlorophyll derivatives may not be as safe as believed and can possibly pose risk to non-target organisms in the environment. We invite the attention of environmental biologists, particularly ecotoxicologists, to contribute their role in making the application of chlorophyll derivatives more environmentally friendly and publicly acceptable.

  2. Cytokinin delays dark-induced senescence in rice by maintaining the chlorophyll cycle and photosynthetic complexes.

    Talla, Sai Krishna; Panigrahy, Madhusmita; Kappara, Saivishnupriya; Nirosha, P; Neelamraju, Sarla; Ramanan, Rajeshwari

    2016-03-01

    The phytohormone cytokinin (CK) is known to delay senescence in plants. We studied the effect of a CK analog, 6-benzyl adenine (BA), on rice leaves to understand the possible mechanism by which CK delays senescence in a drought- and heat-tolerant rice cultivar Nagina22 (N22) using dark-induced senescence (DIS) as a surrogate for natural senescence of leaves. Leaves of N22-H-dgl162, a stay-green mutant of N22, and BA-treated N22 showed retention of chlorophyll (Chl) pigments, maintenance of the Chl a/b ratio, and delay in reduction of both photochemical efficiency and rate of oxygen evolution during DIS. HPLC analysis showed accumulation of 7-hydroxymethyl chlorophyll (HmChl) during DIS, and the kinetics of its accumulation correlated with progression of senescence. Transcriptome analysis revealed that several plastid-localized genes, specifically those associated with photosystem II (PSII), showed higher transcript levels in BA-treated N22 and the stay-green mutant leaves compared with naturally senescing N22 leaves. Real-time PCR analyses showed that genes coding for enzymes associated with Chl a/b interconversion and proteins associated with light-harvesting complexes maintained higher transcript levels up to 72h of DIS following BA treatment. The pigment-protein complexes analyzed by green gel remained intact in both N22-H-dgl162 and BA-treated N22 leaves even after 96h of DIS. Thus, CK delays senescence by accumulation of HmChl and up-regulating genes in the Chl cycle, thereby maintaining the Chl a/b ratio. Also, CK treatment retains higher transcript levels of PSII-related genes, resulting in the stability of photosynthetic pigment complexes and functional stay-greenness in rice. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. Photogeneration of charges in microcrystalline chlorophyll a

    Kassi, Hassan; Barazzouk, Said; Brullemans, Marc; Leblanc, Roger M.; Hotchandani, Surat

    2010-01-01

    The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, r c , from S/I. From the temperature dependence of photogeneration, the initial separation, r 0 , of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r 0 compared to r c leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

  4. Photogeneration of charges in microcrystalline chlorophyll a

    Kassi, Hassan [Scientech R and D, Inc., 2200 Rue Didbec S., Bureau 203, Trois-Rivieres, Trois-Rivieres, QC, G8Z 4H1 (Canada); Barazzouk, Said, E-mail: barazzos@uqtr.c [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Brullemans, Marc [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada); Leblanc, Roger M. [Department of Chemistry, University of Miami, P.O. Box 249118, Coral Gables, FL 33124-0431 (United States); Hotchandani, Surat [Groupe de Recherche en Biologie Vegetale, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, QC, G9A 5H7 (Canada)

    2010-07-01

    The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, r{sub c}, from S/I. From the temperature dependence of photogeneration, the initial separation, r{sub 0}, of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r{sub 0} compared to r{sub c} leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

  5. BOREAS TE-9 NSA Leaf Chlorophyll Density

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Sy, Mikailou

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. These data were collected to help provide an explanation of potential seasonal and spatial changes of leaf pigment properties in boreal forest species at the NSA. At different dates (FFC-Winter, FFC-Thaw, IFC-1, IFC-2, and IMC-3), foliage samples were collected from the upper third of the canopy for five NSA sites (YJP, OJP, OBS, UBS, and OA) near Thompson, Manitoba. Subsamples of 100 needles for black spruce, 20 needles for jack pine, and single leaf for trembling aspen were cut into pieces and immersed in a 20-mL DMF aliquot in a Nalgene test tube. The extracted foliage materials were then oven-dried at 68 C for 48 hours and weighed. Extracted leaf dry weight was converted to a total leaf area basis to express the chlorophyll content in mg/sq cm of total leaf area. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  6. Rice gene SDL/RNRS1, encoding the small subunit of ribonucleotide reductase, is required for chlorophyll synthesis and plant growth development.

    Qin, Ran; Zeng, Dongdong; Liang, Rong; Yang, Chengcong; Akhter, Delara; Alamin, Md; Jin, Xiaoli; Shi, Chunhai

    2017-09-05

    A new mutant named sdl (stripe and drooping leaf) was characterized from indica cultivar Zhenong 34 by ethylmethane sulfonate (EMS) mutagenesis. The mutant sdl exhibited development defects including stripe and drooping leaf, dwarfism and deformed floral organs. The gene SDL was found allelic to RNRS1 by map-based cloning, which was homologous to Arabidopsis TSO2 encoding the small subunit of ribonucleotide reductase. The gDNA sequencing results of sdl in mutant showed that there was a repetitive sequence insertion of 138-bp at the 475 th bp in the exon. The redundant sequence was conserved in SDL homologous proteins, which contained the active site (tyrosine), as well as two amino acids glutamate and histidine involved in the binding of iron. There were fewer chloroplasts and grana lamellas in sdl leaf compared with those of wild-type. Additionally, the stripe leaves of sdl seedlings were highly sensitive to temperature, since the chlorophyll content was increased with the temperature rising. The drooping leaf of sdl might be resulted from the disappearance of vascular bundles and mesophyll cells in both leaf midrib and lateral veins. Fittingly to the phenotypes of mutant sdl, the expression levels of genes associated with photosynthesis and chlorophyll synthesis were found to be down- or up-regulated at different temperatures in mutant sdl. Also, the transcriptional levels of genes related to plant height and floral organ formation showed obvious differences between wild-type and sdl. The "SDL/RNRS1" was, hence, required for the chlorophyll biosynthesis and also played pleiotropic roles in the regulation of plant development. Copyright © 2017. Published by Elsevier B.V.

  7. Assessment of water pollution by airborne measurement of chlorophyll

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1972-01-01

    Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided.

  8. A database of chlorophyll a in Australian waters

    Davies, Claire H.; Ajani, Penelope; Armbrecht, Linda; Atkins, Natalia; Baird, Mark E.; Beard, Jason; Bonham, Pru; Burford, Michele; Clementson, Lesley; Coad, Peter; Crawford, Christine; Dela-Cruz, Jocelyn; Doblin, Martina A.; Edgar, Steven; Eriksen, Ruth; Everett, Jason D.; Furnas, Miles; Harrison, Daniel P.; Hassler, Christel; Henschke, Natasha; Hoenner, Xavier; Ingleton, Tim; Jameson, Ian; Keesing, John; Leterme, Sophie C.; James McLaughlin, M.; Miller, Margaret; Moffatt, David; Moss, Andrew; Nayar, Sasi; Patten, Nicole L.; Patten, Renee; Pausina, Sarah A.; Proctor, Roger; Raes, Eric; Robb, Malcolm; Rothlisberg, Peter; Saeck, Emily A.; Scanes, Peter; Suthers, Iain M.; Swadling, Kerrie M.; Talbot, Samantha; Thompson, Peter; Thomson, Paul G.; Uribe-Palomino, Julian; van Ruth, Paul; Waite, Anya M.; Wright, Simon; Richardson, Anthony J.

    2018-02-01

    Chlorophyll a is the most commonly used indicator of phytoplankton biomass in the marine environment. It is relatively simple and cost effective to measure when compared to phytoplankton abundance and is thus routinely included in many surveys. Here we collate 173, 333 records of chlorophyll a collected since 1965 from Australian waters gathered from researchers on regular coastal monitoring surveys and ocean voyages into a single repository. This dataset includes the chlorophyll a values as measured from samples analysed using spectrophotometry, fluorometry and high performance liquid chromatography (HPLC). The Australian Chlorophyll a database is freely available through the Australian Ocean Data Network portal (https://portal.aodn.org.au/). These data can be used in isolation as an index of phytoplankton biomass or in combination with other data to provide insight into water quality, ecosystem state, and relationships with other trophic levels such as zooplankton or fish.

  9. Investigation into robust spectral indices for leaf chlorophyll estimation

    Main, R

    2011-11-01

    Full Text Available remote sensing data, new users are faced with a plethora of options when choosing an optical index to relate to their chosen or canopy parameter. The literature base regarding optical indices (particularly chlorophyll indices) is wide ranging...

  10. Relationship between chlorophyll-a and column primary production

    Dalal, S.G.; Bhargava, R.M.S.

    Relationship between surface chlorophyll a and column primary production has been established to help in estimating the latter more quickly and accurately. The equation derived is Primary Production, y = 0.54 Ln Chl a - 0.6. The relationship...

  11. Effects of copper stress on antioxidative enzymes, chlorophyll and ...

    Effects of copper stress on antioxidative enzymes, chlorophyll and protein content in Atriplex ... Journal Home > Vol 10, No 50 (2011) > ... The aim of this work was to investigate some enzymatic systems response of this plant to copper stress.

  12. Chlorophyll modulation of mixed layer thermodynamics in a mixed ...

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    in a mixed-layer isopycnal General Circulation Model – An ... three dimensional ocean circulation theory combined with solar radiation transfer process. 1. .... temperature decrease compared with simulation without chlorophyll (bottom panel).

  13. Endolithic chlorophyll d-containing phototrophs

    Behrendt, Lars; Larkum, Anthony W D; Norman, Anders

    2011-01-01

    hyperspectral and variable chlorophyll fluorescence imaging, scanning electron microscopy, photopigment analysis and DNA sequencing to show that Acaryochloris-like cyanobacteria thrive underneath crustose coralline algae in a widespread endolithic habitat on coral reefs. This finding suggests an important role...

  14. Tolerance of some potato mutants induced with gamma irradiation to drought in vitro

    Al-Safadi, B.; Ayyoubi, Z.

    2006-04-01

    An in vitro selection program was conducted in order to improve potato (Solanum tuberosum) tolerance to drought. Potato mutant plants were obtained through a previously conducted mutation breeding program on three potato cultivars (Draga, Spunta, and Diamant) aimed at improving potato tolerance to salinity and resistance to late blight disease. In order to apply selection pressure, growth media (MS based) were prepared with the addition of 1%, 2%, 3% concentrations of Poly Ethylene Glycol (PEG). As a result, three mutants were selected that were tolerant to water stress (i.e. drought tolerant) two of which came from the cultivar Draga and one from Spunta. Physiological growth parameters (plant length, leaf number, branch number, roots number, leaf area, stomata number, and chlorophyll concentration content) were taken on the growing plantlets. The selected mutants were distinguished with some characteristics which can help in their tolerance to drought. Some of these characteristics were an increase in leaf number, root number, and a decrease in stomata number. However a reduction in chlorophyll content was observed as compared with the control. These mutant lines will need further selection in the field for plants with larger tubers before they can be considered as certified lines. (author)

  15. Evaluation of tall rice mutant

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1989-01-01

    One tall mutant (Mut NS1) of rice variety Nizersail was put to multilocation on-farm trial. It showed improvement over the parent in respect of by earlier maturity and higher grain yield at all locations and thus it appears as an improved mutant of Nizersail. (author). 6 refs

  16. A Role for TIC55 as a Hydroxylase of Phyllobilins, the Products of Chlorophyll Breakdown during Plant Senescence[OPEN

    Christ, Bastien; Das, Aditi; Hörtensteiner, Stefan

    2016-01-01

    Chlorophyll degradation is the most obvious hallmark of leaf senescence. Phyllobilins, linear tetrapyrroles that are derived from opening of the chlorin macrocycle by the Rieske-type oxygenase PHEOPHORBIDE a OXYGENASE (PAO), are the end products of chlorophyll degradation. Phyllobilins carry defined modifications at several peripheral positions within the tetrapyrrole backbone. While most of these modifications are species-specific, hydroxylation at the C32 position is commonly found in all species analyzed to date. We demonstrate that this hydroxylation occurs in senescent chloroplasts of Arabidopsis thaliana. Using bell pepper (Capsicum annuum) chromoplasts, we establish that phyllobilin hydroxylation is catalyzed by a membrane-bound, molecular oxygen-dependent, and ferredoxin-dependent activity. As these features resemble the requirements of PAO, we considered membrane-bound Rieske-type oxygenases as potential candidates. Analysis of mutants of the two Arabidopsis Rieske-type oxygenases (besides PAO) uncovered that phyllobilin hydroxylation depends on TRANSLOCON AT THE INNER CHLOROPLAST ENVELOPE55 (TIC55). Our work demonstrates a catalytic activity for TIC55, which in the past has been considered as a redox sensor of protein import into plastids. Given the wide evolutionary distribution of both PAO and TIC55, we consider that chlorophyll degradation likely coevolved with land plants. PMID:27655840

  17. Tomato seeds maturity detection system based on chlorophyll fluorescence

    Li, Cuiling; Wang, Xiu; Meng, Zhijun

    2016-10-01

    Chlorophyll fluorescence intensity can be used as seed maturity and quality evaluation indicator. Chlorophyll fluorescence intensity of seed coats is tested to judge the level of chlorophyll content in seeds, and further to judge the maturity and quality of seeds. This research developed a detection system of tomato seeds maturity based on chlorophyll fluorescence spectrum technology, the system included an excitation light source unit, a fluorescent signal acquisition unit and a data processing unit. The excitation light source unit consisted of two high power LEDs, two radiators and two constant current power supplies, and it was designed to excite chlorophyll fluorescence of tomato seeds. The fluorescent signal acquisition unit was made up of a fluorescence spectrometer, an optical fiber, an optical fiber scaffolds and a narrowband filter. The data processing unit mainly included a computer. Tomato fruits of green ripe stage, discoloration stage, firm ripe stage and full ripe stage were harvested, and their seeds were collected directly. In this research, the developed tomato seeds maturity testing system was used to collect fluorescence spectrums of tomato seeds of different maturities. Principal component analysis (PCA) method was utilized to reduce the dimension of spectral data and extract principal components, and PCA was combined with linear discriminant analysis (LDA) to establish discriminant model of tomato seeds maturity, the discriminant accuracy was greater than 90%. Research results show that using chlorophyll fluorescence spectrum technology is feasible for seeds maturity detection, and the developed tomato seeds maturity testing system has high detection accuracy.

  18. Estimating chlorophyll content from Eucalyptus dunnii leaves by reflectance values

    João Alexandre Lopes Dranski

    2016-06-01

    Full Text Available This study aimed to estimate photosynthetic pigments contents from leaves of Eucalyptus dunni Maiden based on values of reflectance spectra of red, green and blue colors obtained with a digital color analyzer. We collected fifty leaves from the lower third of the crown of twenty trees including young as well as mature leaves. From each leaf an area of 14 cm2 of the leaf blade was cut in which we measured reflectance values on the red, green and blue spectra with a portable digital colorimeter, obtained relative index of chlorophyll with a SPAD – 502 and determined the content of the chlorophyll a, b, and a + b by classic method of solvent extraction. We submitted the data to multiple linear regression and nonlinear analysis at 5% of error probability. It was evaluated the occurrence of multicollinearity. The negative exponential model resulted in good fit when data from red spectrum was used for chlorophyll a, green spectrum for chlorophyll b and a + b, making possible correlation coefficients between the estimated values and the extracted above 0.85. Except for the chlorophyll a content, the accuracy in estimates of photosynthetic pigments were higher than estimated by the chlorophyll meter, even with linearity between methods. Therefore, it is possible to estimate photosynthetic pigments on E. dunni leaves through values of red and green wavelengths from a digital color analyser.

  19. Towards a merged satellite and in situ fluorescence ocean chlorophyll product

    H. Lavigne

    2012-06-01

    Full Text Available Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represent the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles constitute the greatest data set available, because fluorometers have operated routinely on oceanographic cruises since the 1970s. Nevertheless, fluorescence is only a proxy of the total chlorophyll a concentration and a data calibration is required. Calibration issues are, however, sources of uncertainty, and they have prevented a systematic and wide range exploitation of the fluorescence data set. In particular, very few attempts to standardize the fluorescence databases have been made. Consequently, merged estimations with other data sources (e.g. satellite are lacking.

    We propose a merging method to fill this gap. It consists firstly in adjusting the fluorescence profile to impose a zero chlorophyll a concentration at depth. Secondly, each point of the fluorescence profile is then multiplied by a correction coefficient, which forces the chlorophyll a integrated content measured on the fluorescence profile to be consistent with the concomitant ocean colour observation. The method is close to the approach proposed by Boss et al. (2008 to correct fluorescence data of a profiling float, although important differences do exist. To develop and test our approach, in situ data from three open ocean stations (BATS, HOT and DYFAMED were used. Comparison of the so-called "satellite-corrected" fluorescence profiles with concomitant bottle-derived estimations of chlorophyll a concentration was performed to evaluate the final error (estimated at 31%. Comparison with the Boss et al. (2008 method, using a subset of the DYFAMED data set, demonstrated that the methods have similar

  20. Water-Soluble Chlorophyll Protein (WSCP) Stably Binds Two or Four Chlorophylls.

    Palm, Daniel M; Agostini, Alessandro; Tenzer, Stefan; Gloeckle, Barbara M; Werwie, Mara; Carbonera, Donatella; Paulsen, Harald

    2017-03-28

    Water-soluble chlorophyll proteins (WSCPs) of class IIa from Brassicaceae form tetrameric complexes containing one chlorophyll (Chl) per apoprotein but no carotenoids. The complexes are remarkably stable toward dissociation and protein denaturation even at 100 °C and extreme pH values, and the Chls are partially protected against photooxidation. There are several hypotheses that explain the biological role of WSCPs, one of them proposing that they function as a scavenger of Chls set free upon plant senescence or pathogen attack. The biochemical properties of WSCP described in this paper are consistent with the protein acting as an efficient and flexible Chl scavenger. At limiting Chl concentrations, the recombinant WSCP apoprotein binds substoichiometric amounts of Chl (two Chls per tetramer) to form complexes that are as stable toward thermal dissociation, denaturation, and photodamage as the fully pigmented ones. If more Chl is added, these two-Chl complexes can bind another two Chls to reach the fully pigmented state. The protection of WSCP Chls against photodamage has been attributed to the apoprotein serving as a diffusion barrier for oxygen, preventing its access to triplet excited Chls and, thus, the formation of singlet oxygen. By contrast, the sequential binding of Chls by WSCP suggests a partially open or at least flexible structure, raising the question of how WSCP photoprotects its Chls without the help of carotenoids.

  1. Evaluation of nitrogen status and total chlorophyll in longkong (Aglaia dookkoo Griff. leaves under water stress using a chlorophyll meter

    Sdoodee, S.

    2005-07-01

    Full Text Available A chlorophyll meter (SPAD-502 was used to assess nitrogen status and total chlorophyll in longkong leaves, leaves from twelve of 10-year-old trees grown in the experimental plot at Prince of Songkla University, Songkhla province. The relationship between SPAD-502 meter reading and nitrogen status and total chlorophyll content analyzed in the laboratory was evaluated during 8 months (May-December 2003. It was found that the trend of the relationships in each month was similar. There was no significant differenceamong regression linears of all months. The data of 8 months showed that SPAD-reading and nitrogen content, and SPAD-reading and total chlorophyll content were related in a positive manner. They were Y = 0.19X+10.10, r = 0.76** (n = 240, and Y = 0.43X-7.89, r = 0.79** (n = 400, respectively. The SPAD-502 was then used to assess total nitrogen and total chlorophyll content during imposed water stress. Fifteen 4-yearold plants were grown in pots (each pot containing 50 kg soil volume. The experiment was arranged in acompletely randomized design with 3 treatments: (1 daily watering (2 once watering on day 7 (3 no watering with 5 replications during 14 days of the experimental period. Measurements showed a continuous decrease of SPAD-reading in the treatment of no watering. On day 14, a significant difference of SPAD- reading values between the treatment of daily watering and no watering was found. Then, the values of nitrogen content and total chlorophyll were assessed by using the linear regression equations. From the result, it is suggested that the measurement by chlorophyll meter is a rapid technique for the evaluation of total chlorophyll and nitrogen status in longkong leaves during water stress.

  2. Lack of Neuronal IFN-β-IFNAR Causes Lewy Body- and Parkinson's Disease-like Dementia

    Ejlerskov, Patrick; Hultberg, Jeanette Göransdotter; Wang, JunYang

    2015-01-01

    -causing mutant proteins. Mice lacking Ifnb function exhibited motor and cognitive learning impairments with accompanying α-synuclein-containing Lewy bodies in the brain, as well as a reduction in dopaminergic neurons and defective dopamine signaling in the nigrostriatal region. Lack of IFN-β signaling caused...

  3. HPLC Analysis of Chlorophyll a, Chlorophyll b, and Beta-Carotene in Collard Greens: A Project for a Problem-Oriented Laboratory Course.

    Silveira, Augustine, Jr.; And Others

    1984-01-01

    High performance liquid chromatography (HPLC) is used to separate and quantitate beta-carotene, chlorophyll a, and chlorophyll b originating from collard greens. Experimental procedures used and typical results obtained are discussed. (JN)

  4. Chlorophyll Can Be Reduced in Crop Canopies with Little Penalty to Photosynthesis1[OPEN

    Drewry, Darren T.; VanLoocke, Andy; Cho, Young B.

    2018-01-01

    The hypothesis that reducing chlorophyll content (Chl) can increase canopy photosynthesis in soybeans was tested using an advanced model of canopy photosynthesis. The relationship among leaf Chl, leaf optical properties, and photosynthetic biochemical capacity was measured in 67 soybean (Glycine max) accessions showing large variation in leaf Chl. These relationships were integrated into a biophysical model of canopy-scale photosynthesis to simulate the intercanopy light environment and carbon assimilation capacity of canopies with wild type, a Chl-deficient mutant (Y11y11), and 67 other mutants spanning the extremes of Chl to quantify the impact of variation in leaf-level Chl on canopy-scale photosynthetic assimilation and identify possible opportunities for improving canopy photosynthesis through Chl reduction. These simulations demonstrate that canopy photosynthesis should not increase with Chl reduction due to increases in leaf reflectance and nonoptimal distribution of canopy nitrogen. However, similar rates of canopy photosynthesis can be maintained with a 9% savings in leaf nitrogen resulting from decreased Chl. Additionally, analysis of these simulations indicate that the inability of Chl reductions to increase photosynthesis arises primarily from the connection between Chl and leaf reflectance and secondarily from the mismatch between the vertical distribution of leaf nitrogen and the light absorption profile. These simulations suggest that future work should explore the possibility of using reduced Chl to improve canopy performance by adapting the distribution of the “saved” nitrogen within the canopy to take greater advantage of the more deeply penetrating light. PMID:29061904

  5. The Swedish mutant barley collection

    1989-01-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  6. The Swedish mutant barley collection

    NONE

    1989-07-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  7. Lack of Phosphatidylglycerol Inhibits Chlorophyll Biosynthesis at Multiple Sites and Limits Chlorophyllide Reutilization in Synechocystis sp Strain PCC 6803

    Kopečná, Jana; Pilný, Jan; Krynická, Vendula; Tomčala, Aleš; Kis, M.; Gombos, Z.; Komenda, Josef; Sobotka, Roman

    2015-01-01

    Roč. 169, č. 2 (2015), s. 1307-1317 ISSN 0032-0889 R&D Projects: GA MŠk LO1416; GA MŠk EE2.3.30.0059; GA ČR GBP501/12/G055 Institutional support: RVO:61388971 ; RVO:60077344 Keywords : II REACTION-CENTER * PHOTOSYSTEM-II * SP PCC-6803 Subject RIV: CE - Biochemistry Impact factor: 6.280, year: 2015

  8. A NAP-AAO3 Regulatory Module Promotes Chlorophyll Degradation via ABA Biosynthesis in Arabidopsis Leaves[W][OPEN

    Yang, Jiading; Worley, Eric

    2014-01-01

    Chlorophyll degradation is an important part of leaf senescence, but the underlying regulatory mechanisms are largely unknown. Excised leaves of an Arabidopsis thaliana NAC-LIKE, ACTIVATED BY AP3/PI (NAP) transcription factor mutant (nap) exhibited lower transcript levels of known chlorophyll degradation genes, STAY-GREEN1 (SGR1), NON-YELLOW COLORING1 (NYC1), PHEOPHYTINASE (PPH), and PHEIDE a OXYGENASE (PaO), and higher chlorophyll retention than the wild type during dark-induced senescence. Transcriptome coexpression analysis revealed that abscisic acid (ABA) metabolism/signaling genes were disproportionately represented among those positively correlated with NAP expression. ABA levels were abnormally low in nap leaves during extended darkness. The ABA biosynthetic genes 9-CIS-EPOXYCAROTENOID DIOXYGENASE2, ABA DEFICIENT3, and ABSCISIC ALDEHYDE OXIDASE3 (AAO3) exhibited abnormally low transcript levels in dark-treated nap leaves. NAP transactivated the promoter of AAO3 in mesophyll cell protoplasts, and electrophoretic mobility shift assays showed that NAP can bind directly to a segment (−196 to −162 relative to the ATG start codon) of the AAO3 promoter. Exogenous application of ABA increased the transcript levels of SGR1, NYC1, PPH, and PaO and suppressed the stay-green phenotype of nap leaves during extended darkness. Overexpression of AAO3 in nap leaves also suppressed the stay-green phenotype under extended darkness. Collectively, the results show that NAP promotes chlorophyll degradation by enhancing transcription of AAO3, which leads to increased levels of the senescence-inducing hormone ABA. PMID:25516602

  9. Characterization of Saccharomyces cerevisiae suppressor mutants devoid of the membrane lipid phosphatidylcholine

    Bao, X.

    2018-01-01

    Phosphatidylcholine (PC) is the most abundant membrane lipid in most eukaryotes and considered essential. The yeast double deletion mutant cho2opi3 lacks the methyltransferases converting phosphatidylethanolamine (PE) to PC. As a consequence, the cho2opi3 mutant is a choline auxotroph that relies on

  10. CHLOROPHYLL a FLUORESCENCE ANALYSIS IN FORESTS

    M. Pollastrini

    2016-03-01

    Full Text Available A European-wide assessment of chlorophyll a fluorescence (ChlF, prompt fluorescence on dark-adapted samples parameters in forest ecosystems was carried out in the years 2012-2013, within the 7FP FunDivEUROPE project. A total of 1596 trees growing in 209 stands distributed in six countries, from Mediterranean to boreal sites, were sampled. This paper shows the applicability of the ChlF in forest ecology surveys, the protocols adopted for leaf sampling and ChlF measurements, the variability of the ChlF parameters within and between trees, their dependence to environmental factors and the relationships with other functional leaf traits. The most relevant findings were as follows: (i The least variable ChlF parameter within and between the trees was the maximum quantum yield of primary photochemistry (FV/FM, whereas the performance indices (PIABS and PITOT showed the highest variability; (ii for a given tree, the ChlF parameters measured at two heights of the crown (top and bottom leaves were correlated and, in coniferous species, the ChlF parameters were correlated between different needle age classes (from the current year and previous year; (iii the ChlF parameters showed a geographical pattern, and the photochemical performance of the forest trees was higher in central Europe than in the edge sites (northernmost and southernmost; and (iv ChlF parameters showed different sensitivity to specific environmental factors: FV/FM increased with the increase of the leaf area index of stands and soil fertility; ΔVIP was reduced under high temperature and drought. The photochemical responses of forest tree species, analyzed with ChlF parameters, were influenced by the ecology of the trees (i.e. their functional groups, continental distribution, successional status, etc., tree species’ richness and composition of the stands. Our results support the applicability and usefulness of the ChlF in forest monitoring investigations on a large spatial scale and

  11. Characterization of yeast mutants lacking alkaline ceramidases YPC1 and YDC1

    Voynova, Natalia S; Mallela, Shamroop K; Vazquez, Hector M

    2014-01-01

    Humans and yeast possess alkaline ceramidases located in the early secretory pathway. Single deletions of the highly homologous yeast alkaline ceramidases YPC1 and YDC1 have very little genetic interactions or phenotypes. Here, we performed chemical-genetic screens to find deletions...... reduces chronological life span. A novel finding is that, when working backwards as a ceramide synthase in vivo, Ypc1p prefers C24 and C26 fatty acids as substrates, whereas it prefers C16:0, when solubilized in detergent and working in vitro. Therefore, its physiological activity may not only concern...... the minor ceramides containing C14 and C16. Intriguingly, so far the sole discernable benefit of conserving YPC1 for yeast resides with its ability to convey relative resistance toward H2 O2 ....

  12. Functional characterization of Bombyx mori nucleopolyhedrovirus mutant lacking late expression factor 9.

    Zhang, Y; Shi, Y; Yu, H; Li, J; Quan, Y; Shu, T; Nie, Z; Zhang, Y; Yu, W

    Baculoviridae is a family of invertebrate viruses with large double-stranded DNA genomes. Proteins encoded by some late expression factor (lef ) genes are involved in the regulation of viral gene expression. Lef-9 is one of four transcription-specific Lefs, which are components of the virus-encoded RNA polymerase, and can initiate and transcribe late and very late genes. As a multifunctional protein encoded by the Bombyx mori nucleopolyhedrovirus (BmNPV), Lef-9 may be involved in the regulation of viral propagation. However, the underlying mechanism remains unclear. To determine the role of lef-9 in baculovirus infection, lef-9-knockout virus (lef-9-KO-Bacmid virus) was constructed using the Red recombination system, and the Bac-to-Bac system was used to prepare lef-9-repaired virus (lef-9-Re-Bacmid virus). The lef-9-KO virus did not produce infectious viruses or show infection activity, while the lef-9-repaired virus recovered both. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis of the transcription levels in wild-type-Bacmid, lef-9-KO-Bacmid, and lef-9-Re-Bacmid viruses showed that the lef-9-KO bacmid had little effect on viral genome replication. However, the transcription levels of the early and late viral genes, lef-3, ie-1, vp39, and p10, were significantly lower in BmN cells transfected with lef-9-KO-Bacmids than in the controls. Electron microscopy showed no visible enveloped virions in cells transfected with lef-9-KO-Bacmids, while many mature virions in cells transfected with lef-9-Re-Bacmid and wt-Bacmid were present. Thus, lef-9 was not essential for viral genome replication, but significantly affected viral gene transcription and expression in all periods of cell life cycle.

  13. Chlorophyll a is a favorable substrate for Chlamydomonas Mg-dechelatase encoded by STAY-GREEN.

    Matsuda, Kaori; Shimoda, Yousuke; Tanaka, Ayumi; Ito, Hisashi

    2016-12-01

    Mg removal from chlorophyll by Mg-dechelatase is the first step of chlorophyll degradation. Recent studies showed that in Arabidopsis, Stay Green (SGR) encodes Mg-dechelatase. Though the Escherichia coli expression system is advantageous for investigating the properties of Mg-dechelatase, Arabidopsis Mg-dechelatase is not successfully expressed in E. coli. Chlamydomonas reinhardtii SGR (CrSGR) has a long, hydrophilic tail, suggesting that active CrSGR can be expressed in E. coli. After the incubation of chlorophyll a with CrSGR expressed in E. coli, pheophytin a accumulated, indicating that active CrSGR was expressed in E. coli. Substrate specificity of CrSGR against chlorophyll b and an intermediate molecule of the chlorophyll b degradation pathway was examined. CrSGR exhibited no activity against chlorophyll b and low activity against 7-hydroxymethyl chlorophyll a, consistent with the fact that chlorophyll b is degraded only after conversion to chlorophyll a. CrSGR exhibited low activity against divinyl chlorophyll a and chlorophyll a', and no activity against chlorophyllide a, protochlorophyll a, chlorophyll c 2 , and Zn-chlorophyll a. These observations indicate that chlorophyll a is the most favorable substrate for CrSGR. When CrSGR was expressed in Arabidopsis cells, the chlorophyll content decreased, further confirming that SGR has Mg-dechelating activity in chloroplasts. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. APPLICATION OF MODULATED CHLOROPHYLL FLUORESCENCE AND MODULATED CHLOROPHYLL FLUORESCENCE IMAGING IN STUDYING ENVIRONMENTAL STRESSES EFFECT

    L. Guidi

    2016-03-01

    Full Text Available Chlorophyll (Chl a fluorescence is a widely used tool to monitor the photosynthetic process in plants subjected to environmental stresses.this review reports the theoretical bases of Chl fluorescence, and the significance of the most important Chl fluorescence parameters. it also reportshow these parameters can be utilised to estimate changes in photosystem ii (PSII photochemistry, linear electron flux and energy dissipationmechanisms. the relation between actual PSII photochemistry and CO2 assimilation is discussed, as is the role of photochemical andnon-photochemical quenching in inducing changes in PSII activity. the application of Chl fluorescence imaging to study heterogeneity on leaflamina is also considered. this review summarises only some of the results obtained by this methodology to study the effects of differentenvironmental stresses, namely water and nutrients availability, pollutants, temperature and salinity.

  15. Chlorophyll biosynthesis and assembly into chlorophyll-protein complexes in isolated developing chloroplasts

    Bhaya, D.; Castelfranco, P.A.

    1985-01-01

    Isolated developing plastids from greening cucumber cotyledons or from photoperiodically grown pea seedlings incorporated 14 C-labeled 5-aminolevulinic acid (ALA) into chlorophyll (Chl). Incorporation was light dependent, enhanced by S-adenosylmethionine, and linear for 1 hr. The in vitro rate of Chl synthesis from ALA was comparable to the in vivo rate of Chl accumulation. Levulinic acid and dioxoheptanoic acid strongly inhibited Chl synthesis but not plastid protein synthesis. Neither chloramphenicol nor spectinomycin affected Chl synthesis, although protein synthesis was strongly inhibited. Components of thylakoid membranes from plastids incubated with [ 14 C]ALA were resolved by electrophoresis and then subjected to autoradiography. This work showed that (i) newly synthesized Chl was assembled into Chl-protein complexes and (ii) the inhibition of protein synthesis during the incubation did not alter the labeling pattern. Thus, there was no observable short-term coregulation between Chl synthesis (from ALA) and the synthesis of membrane proteins in isolated plastids

  16. Isolation and partial characterization of mutants with elevated lipid content in Chlorella sorokiniana and Scenedesmus obliquus.

    Vigeolas, Hélène; Duby, Francéline; Kaymak, Esra; Niessen, Guillaume; Motte, Patrick; Franck, Fabrice; Remacle, Claire

    2012-11-30

    This paper describes the isolation and partial biomass characterization of high triacylglycerol (TAG) mutants of Chlorella sorokiniana and Scenedesmus obliquus, two algal species considered as potential source of biodiesel. Following UV mutagenesis, 2000 Chlorella and 2800 Scenedesmus colonies were screened with a method based on Nile Red fluorescence. Several mutants with high Nile Red fluorescence were selected by this high-throughput method in both species. Growth and biomass parameters of the strongest mutants were analyzed in detail. All of the four Chlorella mutants showed no significant changes in growth rate, cell weight, cell size, protein and chlorophyll contents on a per cell basis. Whereas all contained elevated total lipid and TAG content per unit of dry weight, two of them were also affected for starch metabolism, suggesting a change in biomass/storage carbohydrate composition. Two Scenedesmus mutants showed a 1.5 and 2-fold increased cell weight and larger cells compared to the wild type, which led to a general increase of biomass including total lipid and TAG content on a per cell basis. Such mutants could subsequently be used as commercial oleaginous algae and serve as an alternative to conventional petrol. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. GUN4-Porphyrin Complexes Bind the ChlH/GUN5 Subunit of Mg-Chelatase and Promote Chlorophyll Biosynthesis in Arabidopsis[W

    Adhikari, Neil D.; Froehlich, John E.; Strand, Deserah D.; Buck, Stephanie M.; Kramer, David M.; Larkin, Robert M.

    2011-01-01

    The GENOMES UNCOUPLED4 (GUN4) protein stimulates chlorophyll biosynthesis by activating Mg-chelatase, the enzyme that commits protoporphyrin IX to chlorophyll biosynthesis. This stimulation depends on GUN4 binding the ChlH subunit of Mg-chelatase and the porphyrin substrate and product of Mg-chelatase. After binding porphyrins, GUN4 associates more stably with chloroplast membranes and was proposed to promote interactions between ChlH and chloroplast membranes—the site of Mg-chelatase activity. GUN4 was also proposed to attenuate the production of reactive oxygen species (ROS) by binding and shielding light-exposed porphyrins from collisions with O2. To test these proposals, we first engineered Arabidopsis thaliana plants that express only porphyrin binding–deficient forms of GUN4. Using these transgenic plants and particular mutants, we found that the porphyrin binding activity of GUN4 and Mg-chelatase contribute to the accumulation of chlorophyll, GUN4, and Mg-chelatase subunits. Also, we found that the porphyrin binding activity of GUN4 and Mg-chelatase affect the associations of GUN4 and ChlH with chloroplast membranes and have various effects on the expression of ROS-inducible genes. Based on our findings, we conclude that ChlH and GUN4 use distinct mechanisms to associate with chloroplast membranes and that mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light by a mechanism that is potentially complex. PMID:21467578

  18. An overview of remote sensing of chlorophyll fluorescence

    Xing, Xiao-Gang; Zhao, Dong-Zhi; Liu, Yu-Guang; Yang, Jian-Hong; Xiu, Peng; Wang, Lin

    2007-03-01

    Besides empirical algorithms with the blue-green ratio, the algorithms based on fluorescence are also important and valid methods for retrieving chlorophyll-a concentration in the ocean waters, especially for Case II waters and the sea with algal blooming. This study reviews the history of initial cognitions, investigations and detailed approaches towards chlorophyll fluorescence, and then introduces the biological mechanism of fluorescence remote sensing and main spectral characteristics such as the positive correlation between fluorescence and chlorophyll concentration, the red shift phenomena. Meanwhile, there exist many influence factors that increase complexity of fluorescence remote sensing, such as fluorescence quantum yield, physiological status of various algae, substances with related optical property in the ocean, atmospheric absorption etc. Based on these cognitions, scientists have found two ways to calculate the amount of fluorescence detected by ocean color sensors: fluorescence line height and reflectance ratio. These two ways are currently the foundation for retrieval of chlorophyl l - a concentration in the ocean. As the in-situ measurements and synchronous satellite data are continuously being accumulated, the fluorescence remote sensing of chlorophyll-a concentration in Case II waters should be recognized more thoroughly and new algorithms could be expected.

  19. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    Jesus R. Millan-Almaraz

    2012-08-01

    Full Text Available Chlorophyll fluorescence can be defined as the red and far-red light emitted by photosynthetic tissue when it is excited by a light source. This is an important phenomenon which permits investigators to obtain important information about the state of health of a photosynthetic sample. This article reviews the current state of the art knowledge regarding the design of new chlorophyll fluorescence sensing systems, providing appropriate information about processes, instrumentation and electronic devices. These types of systems and applications can be created to determine both comfort conditions and current problems within a given subject. The procedure to measure chlorophyll fluorescence is commonly split into two main parts; the first involves chlorophyll excitation, for which there are passive or active methods. The second part of the procedure is to closely measure the chlorophyll fluorescence response with specialized instrumentation systems. Such systems utilize several methods, each with different characteristics regarding to cost, resolution, ease of processing or portability. These methods for the most part include cameras, photodiodes and satellite images.

  20. Instrumentation in Developing Chlorophyll Fluorescence Biosensing: A Review

    Fernandez-Jaramillo, Arturo A.; Duarte-Galvan, Carlos; Contreras-Medina, Luis M.; Torres-Pacheco, Irineo; de J. Romero-Troncoso, Rene; Guevara-Gonzalez, Ramon G.; Millan-Almaraz, Jesus R.

    2012-01-01

    Chlorophyll fluorescence can be defined as the red and far-red light emitted by photosynthetic tissue when it is excited by a light source. This is an important phenomenon which permits investigators to obtain important information about the state of health of a photosynthetic sample. This article reviews the current state of the art knowledge regarding the design of new chlorophyll fluorescence sensing systems, providing appropriate information about processes, instrumentation and electronic devices. These types of systems and applications can be created to determine both comfort conditions and current problems within a given subject. The procedure to measure chlorophyll fluorescence is commonly split into two main parts; the first involves chlorophyll excitation, for which there are passive or active methods. The second part of the procedure is to closely measure the chlorophyll fluorescence response with specialized instrumentation systems. Such systems utilize several methods, each with different characteristics regarding to cost, resolution, ease of processing or portability. These methods for the most part include cameras, photodiodes and satellite images. PMID:23112686

  1. Chlorophyll as a biomarker for early disease diagnosis

    Manzoor Atta, Babar; Saleem, M.; Ali, Hina; Arshad, Hafiz Muhammad Imran; Ahmed, M.

    2018-06-01

    The current study was designed to identify the stage for the diagnosis of disease before visible symptoms appeared. Fluorescence spectroscopy has been employed to identify disease signatures for its early diagnosis in rice plant leaves. Bacterial leaf blight (BLB) diseased and healthy leaf samples were collected from the rice fields in September, 2017 which were then used to record spectra using an excitation wavelength at 410 nm. The spectral range of emission was set from 420 to 800 nm which covers the blue–green and the chlorophyll bands. It was found that diseased leaves have a narrower ‘chlorophyll a’ band than healthy ones, and furthermore, that the emission band at 730 nm was either declined or depleted in the sample with high infection symptoms. In contrast, the blue–green region was observed to increase due to the emergence of disease. As the band intensity of chlorophyll decreases during infection, this decrease in chlorophyll content and increase in the blue–green spectral region could provide a new approach for predicting BLB at an early stage. The important finding was that the chlorophyll degradation and rise in the blue–green region take place in leaves with BLB or during BLB infection. Principal component analysis has been applied to spectral data which successfully separated diseased samples from healthy ones even with very small spectral variations.

  2. Mutants of alfalfa mosaic virus

    Roosien, J.

    1983-01-01

    In this thesis the isolation and characterization of a number of mutants of alfalfa mosaic virus, a plant virus with a coat protein dependent genome, is described. Thermo-sensitive (ts) mutants were selected since, at least theoretically, ts mutations can be present in all virus coded functions. It was found that a high percentage of spontaneous mutants, isolated because of their aberrant symptoms, were ts. The majority of these isolates could grow at the non-permissive temperature in the presence of a single wild type (wt) component. To increase the mutation rate virus preparations were treated with several mutagens. After nitrous acid treatment or irradiation with ultraviolet light, an increase in the level of mutations was observed. UV irradiation was preferred since it did not require large amounts of purified viral components. During the preliminary characterization of potential ts mutants the author also obtained one structural and several symptom mutants which were analysed further (chapter 7, 8 and 9). The properties of the ts mutants are described in chapter 3-7. (Auth.)

  3. Root hair mutants of barley

    Engvild, K.C.; Rasmussen, K.

    2005-01-01

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  4. Growth and sporulation of a pyrimidine spore color mutant of Sordaria fimicola.

    el-Ani, A S

    1967-04-07

    A nonautonomous spore color mutant of Sordaria fimicola is a pyrimidine auxotroph that produces hyaline nonviable ascospores. Uracil, uridine, and cytidine are more effective growth factors than cytosine and thymine and, in high concentrations, render the mutant self-fertile by inducing the ascospores to resume development and maturation. Crosses with the unlinked arginine non-autonomus spore color mutant st-59 yielded the double mutant st-59 pyr that requires both arginine and a pyrimidine for growth, which indicates a lack of suppression of the pyrimidine requirement by the arginine locus.

  5. Detecting crop population growth using chlorophyll fluorescence imaging.

    Wang, Heng; Qian, Xiangjie; Zhang, Lan; Xu, Sailong; Li, Haifeng; Xia, Xiaojian; Dai, Liankui; Xu, Liang; Yu, Jingquan; Liu, Xu

    2017-12-10

    For both field and greenhouse crops, it is challenging to evaluate their growth information on a large area over a long time. In this work, we developed a chlorophyll fluorescence imaging-based system for crop population growth information detection. Modular design was used to make the system provide high-intensity uniform illumination. This system can perform modulated chlorophyll fluorescence induction kinetics measurement and chlorophyll fluorescence parameter imaging over a large area of up to 45  cm×34  cm. The system can provide different lighting intensity by modulating the duty cycle of its control signal. Results of continuous monitoring of cucumbers in nitrogen deficiency show the system can reduce the judge error of crop physiological status and improve monitoring efficiency. Meanwhile, the system is promising in high throughput application scenarios.

  6. Optimal leaf positions for chlorophyll meter measurement in rice

    Zhaofeng eYuan

    2016-05-01

    Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

  7. Investigating the Control of Chlorophyll Degradation by Genomic Correlation Mining.

    Ghandchi, Frederick P; Caetano-Anolles, Gustavo; Clough, Steven J; Ort, Donald R

    2016-01-01

    Chlorophyll degradation is an intricate process that is critical in a variety of plant tissues at different times during the plant life cycle. Many of the photoactive chlorophyll degradation intermediates are exceptionally cytotoxic necessitating that the pathway be carefully coordinated and regulated. The primary regulatory step in the chlorophyll degradation pathway involves the enzyme pheophorbide a oxygenase (PAO), which oxidizes the chlorophyll intermediate pheophorbide a, that is eventually converted to non-fluorescent chlorophyll catabolites. There is evidence that PAO is differentially regulated across different environmental and developmental conditions with both transcriptional and post-transcriptional components, but the involved regulatory elements are uncertain or unknown. We hypothesized that transcription factors modulate PAO expression across different environmental conditions, such as cold and drought, as well as during developmental transitions to leaf senescence and maturation of green seeds. To test these hypotheses, several sets of Arabidopsis genomic and bioinformatic experiments were investigated and re-analyzed using computational approaches. PAO expression was compared across varied environmental conditions in the three separate datasets using regression modeling and correlation mining to identify gene elements co-expressed with PAO. Their functions were investigated as candidate upstream transcription factors or other regulatory elements that may regulate PAO expression. PAO transcript expression was found to be significantly up-regulated in warm conditions, during leaf senescence, and in drought conditions, and in all three conditions significantly positively correlated with expression of transcription factor Arabidopsis thaliana activating factor 1 (ATAF1), suggesting that ATAF1 is triggered in the plant response to these processes or abiotic stresses and in result up-regulates PAO expression. The proposed regulatory network includes the

  8. Mutants induced in winter rye (Secale cereale L.): Short straw-mutant No. 2714 and late-senescence mutant

    Muszynski, S; Darlewska, M [Department of Plant Breeding and Seed Science, Warsaw Agricultural University, Warsaw (Poland)

    1990-01-01

    Full text: Mutants were induced by treating dormant seeds with ionizing radiation (fast neutrons) or chemicals (N-nitroso-N-ethyl urea or sodium azide). Among several mutants obtained, of special value is the short-straw mutant No. 2714 and a late senescent mutant. (author)

  9. Molecular Basis Underlying Leaf Variegation of a Moth Orchid Mutant (Phalaenopsis aphrodite subsp. formosana

    Chi-Chu Tsai

    2017-07-01

    Full Text Available Leaf variegation is often the focus of plant breeding. Here, we studied a variegated mutant of Phalaenopsis aphrodite subsp. formosana, which is usually used as a parent of horticultural breeding, to understand its anatomic and genetic regulatory mechanisms in variegation. Chloroplasts with well-organized thylakoids and starch grains were found only in the mesophyll cells of green sectors but not of yellow sectors, confirming that the variegation belongs to the chlorophyll type. The two-dimensional electrophoresis and LC/MS/MS also reveal differential expressions of PsbP and PsbO between the green and yellow leaf sectors. Full-length cDNA sequencing revealed that mutant transcripts were caused by intron retention. When conditioning on the total RNA expression, we found that the functional transcript of PsbO and mutant transcript of PsbP are higher expressed in the yellow sector than in the green sector, suggesting that the post-transcriptional regulation of PsbO and PsbP differentiates the performance between green and yellow sectors. Because PsbP plays an important role in the stability of thylakoid folding, we suggest that the negative regulation of PsbP may inhibit thylakoid development in the yellow sectors. This causes chlorophyll deficiency in the yellow sectors and results in leaf variegation. We also provide evidence of the link of virus CymMV and the formation of variegation according to the differential expression of CymMV between green and yellow sectors.

  10. Continuous excitation chlorophyll fluorescence parameters: a review for practitioners.

    Banks, Jonathan M

    2017-08-01

    This review introduces, defines and critically reviews a number of chlorophyll fluorescence parameters with specific reference to those derived from continuous excitation chlorophyll fluorescence. A number of common issues and criticisms are addressed. The parameters fluorescence origin (F0) and the performance indices (PI) are discussed as examples. This review attempts to unify definitions for the wide range of parameters available for measuring plant vitality, facilitating their calculation and use. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Overview of Global Monitoring of Terrestrial Chlorophyll Fluorescence from Space

    Guanter, Luis; Zhang, Yongguang; Kohler, Philipp; Walther, Sophia; Frankenberg, Christian; Joiner, Joanna

    2016-01-01

    Despite the critical importance of photosynthesis for the Earth system, understanding how it is influenced by factors such as climate variability, disturbance history, and water or nutrient availability remains a challenge because of the complex interactions and the lack of GPP measurements at various temporal and spatial scales. Space observations of the sun-induced chlorophyll fluorescence (SIF) electromagnetic signal emitted by plants in the 650-850nm spectral range hold the promise of providing a new view of vegetation photosynthesis on a global basis. Global retrievals of SIF from space have recently been achieved from a number of spaceborne spectrometers originally intended for atmospheric research. Despite not having been designed for land applications, such instruments have turned out to provide the necessary spectral and radiometric sensitivity for SIF retrieval from space. The first global measurements of SIF were achieved in 2011 from spectra acquired by the Japanese GOSAT mission launched in 2009. The retrieval takes advantage of the high spectral resolution provided by GOSATs Fourier Transform Spectrometer (FTS) which allows the evaluation of the in-filling of solar Fraunhofer lines by SIF. Unfortunately, GOSAT only provides a sparse spatial sampling with individual soundings separated by several hundred kilometers. Complementary, the Global Ozone Monitoring Experiment-2 (GOME-2) instruments onboard MetOp-A and MetOp-B enable SIF retrievals since 2007 with a continuous and global spatial coverage. GOME-2 measures in the red and near-infrared (NIR) spectral regions with a spectral resolution of 0.5 nm and a pixel size of up to 40x40 km2. Most recently, another global and spatially continuous data set of SIF retrievals at 740 nm spanning the 2003-2012 time frame has been produced from ENVISATSCIAMACHY. This observational scenario has been completed by the first fluorescence data from the NASA-JPL OCO-2 mission (launched in July 2014) and the upcoming

  12. Chlorophyll degradation in the gut of generalist and specialist Lepidopteran caterpillars.

    Badgaa, Amarsanaa; Jia, Aiqun; Ploss, Kerstin; Boland, Wilhelm

    2014-12-01

    Plant feeding herbivores excrete most of the ingested chlorophyll (Chl) as partly degraded derivatives lacking the phytol side chain and the central magnesium ion. An ecological role of digested and degraded Chls in the interactions between insects, their food plant and other insects has been described recently. To gain more information on common degradation patterns in plant-feeding insects, the orals secretions and frass of five Lepidopteran caterpillars covering generalists and specialists, namely Spodoptera littoralis, Spodoptera eridania, Heliothis virescens, Helicoverpa armigera, Manduca sexta, and, for comparison, of the leaf beetle larva Chrysomela lapponica were analyzed for chlorophyll catabolites. The major degradation products were determined as pheohorbide a/b and pyropheophorbide a/b by using LC-MS, LC-NMR, UV, and fluorescence spectrometry. The compounds were not present in fresh leaves of the food plants (Phaseolus lunatus, Nicotiana tabacum). The catabolite spectrum in generalists and specialists was qualitatively similar and could be attributed to the action of gut proteins and the strongly alkaline milieu in the digestive tract. Due to the anaerobic environment of the larval gut, the tetrapyrrole core of the Chl catabolites was not cleaved. Substantial amounts of Chl a/b metabolites were strongly complexed by a protein in the mid-gut.

  13. The magnesium chelation step in chlorophyll biosynthesis. Progress report 1993

    Weinstein, J.D.

    1993-12-31

    Progress is reported on the identification and fractionation of Magnesium chealatase, an enzyme involved in addition of Mg to chlorophyll during the later`s biosynthesis. Progress is documented as a series of synopsis of published and unpublished papers by the author.

  14. Influence of vermicompost humic acid on chlorophyll content and ...

    Influence of vermicompost humic acid on chlorophyll content and acclimatization in banana clone, Enano Guantanamero. Marcia Beatriz Moya Fernández, Esteban Sánchez Chávez, Daniel Cabezas Montero, Andrés Calderín García, Dany Marrero López, Eduardo F. Héctor Ardisana, Sandra Pérez Álvarez ...

  15. Improved ocean chlorophyll estimate from remote sensed data: The ...

    Gregg and Conkright (2001) who pioneered the use of the blending technique in an attempt to calibrate ocean chlorophyll, expressed the need for further work to be done in order to obtain improved results. One problem faced when using this technique with spatially sparse data, is distortion of the resulting blended field ...

  16. Identification and classification of vertical chlorophyll patterns in the ...

    A type of artificial neural network called a self-organizing map (SOM) was then used on these four parameters to identify characteristic profiles. The analysis identified a continuum of chlorophyll patterns, from those with large surface peaks (>10 mg m-3) to those with smaller near-surface peaks (<2 mg m-3). The frequency of ...

  17. Chlorophyll as a measure of plant health: Agroecological aspects

    Danijela Pavlović

    2014-03-01

    Full Text Available As photosynthesis is the basic process during which light energy is absorbed and converted into organic matter, the importance of the plant pigment chlorophyll (a and b forms as an intermediary in transformation of the absorbed solar energy and its activity in the process of photosynthesis and synthesis of organic substances in plants are crucial. Therefore, this paper provides an overview of methods for monitoring the optical activity of chlorophyll molecules and methods (non-destructive and destructive for quantification of chlorophyll in plants. These methods are used to estimate the effects of different stress factors (abiotic, biotic and xenobiotic on the efficiency of photosynthesis and bioproductivity, aiming to assess the impact that these limiting factors have on the yield of various cultivars. Also, those methods for analysis of chlorophyll optical activity and/or content are appropriate for assessing the reaction of weed species to different agricultural practices (mineral nutrition, treatment by herbicides, etc. and studies of different aspects of weed ecophysiology and their influence on crop harvest.

  18. Enzyme-assisted extraction of stabilized chlorophyll from spinach.

    Özkan, Gülay; Ersus Bilek, Seda

    2015-06-01

    Zinc complex formation with chlorophyll derivatives in spinach pulp was studied by adding 300ppm Zn(2+) for production of stable food colorant, followed by the heating at 110°C for 15min. Zinc complex formation increased at pH values of 7.0 or greater. Pectinex Ultra SP-L was selected for enzyme-assisted release of zinc-chlorophyll derivatives from spinach pulp. Effect of enzyme concentration (1-9%), treatment temperature (30-60°C), and time (30-210min) on total chlorophyll content (TCC) were optimized using response surface methodology. A quadratic regression model (R(2)=0.9486) was obtained from the experimental design. Optimum treatment conditions were 8% enzyme concentration, 45°C, and 30min, which yielded a 50.747mgTCC/100g spinach pulp. Enzymatic treatment was followed by solvent extraction with ethanol at a solvent-to-sample ratio of 2.5:1 at 60°C for 45min for the highest TCC recovery. Pretreatment with enzyme and extraction in ethanol resulted in 39% increase in Zn-chlorophyll derivative yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Validation of OCM-2 sensor performance in retrieving chlorophyll ...

    Ocean colour; chlorophyll a; total suspended matter; validation; Bay of Bengal; OCM-2. J. Earth Syst. Sci. 122 ... two basins, the Arabian Sea and Bay of Bengal. (BoB). Arabian ... The capability of visible bands of multi-spectral satellite data has ...

  20. Application of a chlorophyll index derived from satellite data to ...

    Application of a chlorophyll index derived from satellite data to investigate the variability of phytoplankton in the Benguela ecosystem. H Demarcq, R Barlow, L Hutchings. Abstract. No Abstract. African Journal of Marine Science Vol.29(2) 2007: pp. 271-282. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD ...

  1. Effect of temperature on accumulation of chlorophylls and leaf ...

    White young shoots from albino tea cultivars have high level of amino acids and are rare and valuable materials for processing green tea. The effects of temperature on leaf colour, accumulation of chlorophylls and leaf ultrastructures of an albino tea cultivar 'Xiaxueya' were investigated. The study showed that the shoot ...

  2. Chlorophyll, nitrogen and antioxidant activities in Cumaru ( Dipteryx ...

    ... by traditional populations and industries using timber and non-timber forest products. This study aimed to analyze the levels of chlorophyll A, B, total ammonia levels, nitrate, proline, electrolyte leakage and activity of oxidative enzymes in evaluation to tolerance of cumaru plants subjected to drought for 21 days of stress.

  3. Using chlorophyll fluorescence to determine stress in Eucalyptus ...

    Using chlorophyll fluorescence to determine stress in Eucalyptus grandis seedlings: scientific paper. ... Southern Forests: a Journal of Forest Science ... factors affect the functioning of the photosynthetic system, the status of the photosynthetic apparatus is a good indicator of the plant in terms of stress and stress adaptation.

  4. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing

    Haiyan Cen

    2017-08-01

    Full Text Available Huanglongbing (HLB is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves. Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.

  5. Effect of organic and inorganic fertilizer on yield and chlorophyll ...

    The effects of amending soil with organic (poultry manure) and inorganic fertilizer on yield and chlorophyll content of maize (Zea mays L.) and sorghum (Sorghum bicolour (L.) Moench) was carried out at the Teaching and Research (T&R) Farm of the Obafemi Awolowo University, (O.A.U.) Ile - Ife, Nigeria. The experiment ...

  6. Chlorophyll meter reading and total nitrogen content applied as ...

    The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content in the leaf in different parts of the crambe plant, depending on the doses of nitrogen applied to the canopy. Randomized block design in a split plot experimental design was used. The plots ...

  7. Mutation of Gly195 of the ChlH subunit of Mg-chelatase reduces chlorophyll and further disrupts PS II assembly in a Ycf48-deficient strain of Synechocystis sp. PCC 6803

    Tim Crawford

    2016-07-01

    Full Text Available Biogenesis of the photosystems in oxygenic phototrophs requires co-translational insertion of chlorophyll a. The first committed step of chlorophyll a biosynthesis is the insertion of a Mg2+ ion into the tetrapyrrole intermediate protoporphyrin IX, catalyzed by Mg-chelatase. We have identified a Synechocystis sp. PCC 6803 strain with a spontaneous mutation in chlH that results in a Gly195 to Glu substitution in a conserved region of the catalytic subunit of Mg-chelatase. Mutant strains containing the ChlH Gly195 to Glu mutation were generated using a two-step protocol that introduced the chlH gene into a putative neutral site in the chromosome prior to deletion of the native gene. The Gly195 to Glu mutation resulted in strains with decreased chlorophyll a. Deletion of the PS II assembly factor Ycf48 in a strain carrying the ChlH Gly195 to Glu mutation did not grow photoautotrophically. In addition, the ChlH-G195E:ΔYcf48 strain showed impaired PS II activity and decreased assembly of PS II centers in comparison to a ΔYcf48 strain. We suggest decreased chlorophyll in the ChlH-G195E mutant provides a background to screen for the role of assembly factors that are not essential under optimal growth conditions.

  8. Evaluation of water quality by chlorophyll and dissolved oxygen

    Latif, Z.; Tasneem, M.A.; Javed, T.; Butt, S.; Fazil, M.; Ali, M.; Sajjad, M.I.

    2002-01-01

    This paper focuses on the impact of Chlorophyll and dissolved Oxygen on water quality. Kalar Kahar and Rawal lakes were selected for this research. A Spectrophotometer was used for determination of Chlorophyll a, Chlorophyll b, Chlorophyll c and Pheophytin pigment. Dissolved Oxygen was measured in situ, using dissolved oxygen meter. The gamma O/sup 18/ of dissolved Oxygen, like concentration, is affected primarily by three processes: air water gas exchange, respiration and photosynthesis; gamma O/sup 18/ is analyzed on isotopic ratio mass spectrometer, after extraction of dissolved Oxygen from water samples, followed by purification and conversion into CO/sub 2/. Rawal lake receives most of the water from precipitation during monsoon period and supplemented by light rains in December and January. This water is used throughout the year for drinking purposes in Rawalpindi city. The water samples were collected from 5, 7.5, and 10 meters of depth for seasonal studies of physiochemical and isotopic parameters of water and dissolved Oxygen. Optimum experimental conditions for delta O/sup 18/ analysis of dissolved Oxygen from aqueous samples were determined. Stratification of dissolved Oxygen was observed in Rawal Lake before rainy season in summer. The water quality deteriorates with depth, because the respiration exceeds the photosynthesis and gas exchange. The concentration and delta O/sup 18/ of dissolved Oxygen show no variation with depth in 1998 winter sampling. Kalar Kahar lake gets water from springs, which are recharged by local rains on the nearby mountains. It is a big lake, with shallow and uniform depth of nearly 1.5 meters. A lot of vegetation can be seen on the periphery of the lake. Algae have grown on the floor of the lake Water samples were collected from the corner with large amount of vegetation and from the center of the lake for dissolved Oxygen and Chlorophyll measurements. Chlorophyll result shows that Kalar Kahar Lake falls in Eutrophic category

  9. Global NOAA CoastWatch Chlorophyll Frontal Product from MODIS/Aqua (NCEI Accession 0110333)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS/Aqua chlorophyll frontal products: the NOAA Okeanos operational production system produces near real-time chlorophyll frontal products (magnitude and...

  10. Ocean Chlorophyll as a Precursor of ENSO: An Earth System Modeling Study

    Park, Jong-Yeon; Dunne, John P.; Stock, Charles A.

    2018-02-01

    Ocean chlorophyll concentration, a proxy for phytoplankton, is strongly influenced by internal ocean dynamics such as those associated with El Niño-Southern Oscillation (ENSO). Observations show that ocean chlorophyll responses to ENSO generally lead sea surface temperature (SST) responses in the equatorial Pacific. A long-term global Earth system model simulation incorporating marine biogeochemical processes also exhibits a preceding chlorophyll response. In contrast to simulated SST anomalies, which significantly lag the wind-driven subsurface heat response to ENSO, chlorophyll anomalies respond rapidly. Iron was found to be the key factor connecting the simulated surface chlorophyll anomalies to the subsurface ocean response. Westerly wind bursts decrease central Pacific chlorophyll by reducing iron supply through wind-driven thermocline deepening but increase western Pacific chlorophyll by enhancing the influx of coastal iron from the maritime continent. Our results mechanistically support the potential for chlorophyll-based indices to inform seasonal ENSO forecasts beyond previously identified SST-based indices.

  11. The effect of acid rain stress on chlorophyll, peroxidase of the conservation of rare earth elements

    Chongling, Y.; Yetang, H.; Xianke, Y.; Shunzhen, F.; Shanql, W.

    1998-01-01

    Full text: Based on pot experiment, the effect of acid rain stress on chlorophyll, peroxidase of wheat, the relationship of them and the conservation of rare earth elements has been studied. The result showed: stress of acid rain resulted in decrease of chlorophyll content and a/b values, chlorophyll a/b value and chlorophyll content is positive correlation with pH value of acid rain: peroxidase activity was gradually rise with pH value decrease, which indirectly increased decomposition intensity of chlorophyll. Decreased content and a/b value of chlorophyll further speeded blade decay affected the transport and transformation of light energy and metabolism of carbohydrates. After being treated by rare earth elements content and pH value of chlorophyll and peroxidase activity could be relatively stable. Therefore, under lower acidity condition, rare earth elements can influence the effect of acid rain on chlorophyll and peroxidase activity of wheat

  12. Mutation induction and evaluation of high yield rice mutants

    Abdul Rahim Harun; Sobri Husein; Rusli Ibrahim

    2006-01-01

    The successful use of plant breeding for improving crops requires the existence of genetic variation of useful traits. Unfortunately, the desired variation is often lacking. However, radiation has been used to induce mutations and thereby generate genetic variation from which desired mutants may be selected. Mutation induction has become a proven way of creating variation within a crop variety. It offers the possibility of inducing desired attributes that either cannot be expressed in nature or have been lost during evolution. Rice is security food crop in Malaysia. Efforts were undertaken to enhance rice yield from 4.0 tones per hectare in 1995 to 5.5 tones per hectare in 2010. Proper management and good varieties are two factors that require for enhancing yield of rice. In this research, purified seeds of MR211 and MR219 were gamma irradiated at 100 to 400 Gray and sown for planting as M1 generation at MARDI experimental plot. The M2 population was sown in bulk with population size around 15,000 to 20,000 plants. Individual plant selection was carried out at maturity and each selected plant became a mutant line of M3 generation. Agronomic trial of M3 mutants lines were conducted in Mardi, Tanjung Karang, Selangor. About 115 of selected mutant lines were evaluated. Each row of those mutant lines were planted in two rows at planting distance of 25cm within and between rows. These mutant lines were visually observed and data were recorded in each of every mutant line. (Author)

  13. Defective glycinergic synaptic transmission in zebrafish motility mutants

    Hiromi Hirata

    2010-01-01

    Full Text Available Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission. Zebrafish bandoneon (beo mutants have a defect in glrbb, one of the duplicated glycine receptor (GlyR β subunit genes. These mutants exhibit a loss of glycinergic synaptic transmission due to a lack of synaptic aggregation of GlyRs. Due to the consequent loss of reciprocal inhibition of motor circuits between the two sides of the spinal cord, motor neurons activate simultaneously on both sides resulting in bilateral contraction of axial muscles of beo mutants, eliciting the so-called ‘accordion’ phenotype. Similar defects in GlyR subunit genes have been observed in several mammals and are the basis for human hyperekplexia/startle disease. By contrast, zebrafish shocked (sho mutants have a defect in slc6a9, encoding GlyT1, a glycine transporter that is expressed by astroglial cells surrounding the glycinergic synapse in the hindbrain and spinal cord. GlyT1 mediates rapid uptake of glycine from the synaptic cleft, terminating synaptic transmission. In zebrafish sho mutants, there appears to be elevated extracellular glycine resulting in persistent inhibition of postsynaptic neurons and subsequent reduced motility, causing the ‘twitch once’ phenotype. We review current knowledge regarding zebrafish ‘accordion’ and ‘twitch once’ mutants, including beo and sho, and report the identification of a new α2 subunit that revises the phylogeny of zebrafish GlyRs.

  14. Defective Glycinergic Synaptic Transmission in Zebrafish Motility Mutants

    Hirata, Hiromi; Carta, Eloisa; Yamanaka, Iori; Harvey, Robert J.; Kuwada, John Y.

    2009-01-01

    Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission. Zebrafish bandoneon (beo) mutants have a defect in glrbb, one of the duplicated glycine receptor (GlyR) β subunit genes. These mutants exhibit a loss of glycinergic synaptic transmission due to a lack of synaptic aggregation of GlyRs. Due to the consequent loss of reciprocal inhibition of motor circuits between the two sides of the spinal cord, motor neurons activate simultaneously on both sides resulting in bilateral contraction of axial muscles of beo mutants, eliciting the so-called ‘accordion’ phenotype. Similar defects in GlyR subunit genes have been observed in several mammals and are the basis for human hyperekplexia/startle disease. By contrast, zebrafish shocked (sho) mutants have a defect in slc6a9, encoding GlyT1, a glycine transporter that is expressed by astroglial cells surrounding the glycinergic synapse in the hindbrain and spinal cord. GlyT1 mediates rapid uptake of glycine from the synaptic cleft, terminating synaptic transmission. In zebrafish sho mutants, there appears to be elevated extracellular glycine resulting in persistent inhibition of postsynaptic neurons and subsequent reduced motility, causing the ‘twitch-once’ phenotype. We review current knowledge regarding zebrafish ‘accordion’ and ‘twitch-once’ mutants, including beo and sho, and report the identification of a new α2 subunit that revises the phylogeny of zebrafish GlyRs. PMID:20161699

  15. Lead pollution: effects on chlorophyll. [Phalaris canariensis, Lemna minor, graminaceae

    Fiussello, N

    1973-01-01

    The emissions of motors are responsible for the high concentrations of lead in soil and plants near roads. In man, when the concentration of lead in blood exceeds the value of 30 ..mu..g/100 ml, is shown a decrease of haemaglobin and an increase of ALA urinary content. Since the early stages of chlorophyll biosynthetic pathway are similar if not identical with those leading to haem as far as protoporphyrin IX, it is interesting to ascertain if lead can specifically interfere in chlorophyll biosynthesis. In sand cultures with 200 p.p.m. of lead (the conc. in roadside soils), after 2 weeks, wheat shows a diminution of 16,5% in fresh weight 7,5% in dry weight and 6,5% in chlorophyll; Phalaris canariensis shows a diminution of 68% f.w., 41% d.w. and 39% chl. in comparison with the controls. A water-plant, Lemna minor, is more sensitive: the chlorophyll content, referred to dry weight, shows after a week a diminution of 32% and 55% with 10/sup -4/M and 10/sup -3/M lead nitrate. Lead in 200 p.p.m. conc. is surely poisonous against the tested plants but a specific action on chlorophyll synthesis could be accepted, at present, only for Lemna minor. It is possible that in wheat and in Phalaris a part of lead is bound in root-system, the more damaged, while in Lemna it can reach more easily the chloroplasts. At present a detectable increase of ALA, in plants treated with lead, has not been proved both in Graminaceae and in Lemna minor.

  16. Portable chlorophyll meter (PCM-502) values are related to total chlorophyll concentration and photosynthetic capacity in papaya (Carica papaya L.)

    This study was carried out to verify the practical use of the portable chlorophyll meter-PCM502 (PCM) in two papaya cultivars with contrasting green coloring of the leaf blade (‘Golden’: yellowish-green; ‘Solo’: dark green). The relationship was studied between the photosynthetic process and leaf n...

  17. Purkinje Cell Compartmentation in the Cerebellum of the Lysosomal Acid Phosphatase 2 Mutant Mouse (Nax - Naked-Ataxia Mutant Mouse)

    Bailey, Karen; Rahimi Balaei, Maryam; Mannan, Ashraf; Del Bigio, Marc R.; Marzban, Hassan

    2014-01-01

    The Acp2 gene encodes the beta subunit of lysosomal acid phosphatase, which is an isoenzyme that hydrolyzes orthophosphoric monoesters. In mice, a spontaneous mutation in Acp2 results in severe cerebellar defects. These include a reduced size, abnormal lobulation, and an apparent anterior cerebellar disorder with an absent or hypoplastic vermis. Based on differential gene expression in the cerebellum, the mouse cerebellar cortex can normally be compartmentalized anteroposteriorly into four transverse zones and mediolaterally into parasagittal stripes. In this study, immunohistochemistry was performed using various Purkinje cell compartmentation markers to examine their expression patterns in the Acp2 mutant. Despite the abnormal lobulation and anterior cerebellar defects, zebrin II and PLCβ4 showed similar expression patterns in the nax mutant and wild type cerebellum. However, fewer stripes were found in the anterior zone of the nax mutant, which could be due to a lack of Purkinje cells or altered expression of the stripe markers. HSP25 expression was uniform in the central zone of the nax mutant cerebellum at around postnatal day (P) 18–19, suggesting that HSP25 immunonegative Purkinje cells are absent or delayed in stripe pattern expression compared to the wild type. HSP25 expression became heterogeneous around P22–23, with twice the number of parasagittal stripes in the nax mutant compared to the wild type. Aside from reduced size and cortical disorganization, both the posterior zone and nodular zone in the nax mutant appeared less abnormal than the rest of the cerebellum. From these results, it is evident that the anterior zone of the nax mutant cerebellum is the most severely affected, and this extends beyond the primary fissure into the rostral central zone/vermis. This suggests that ACP2 has critical roles in the development of the anterior cerebellum and it may regulate anterior and central zone compartmentation. PMID:24722417

  18. Lack of centrioles and primary cilia in STIL(-/-) mouse embryos.

    David, Ahuvit; Liu, Fengying; Tibelius, Alexandra; Vulprecht, Julia; Wald, Diana; Rothermel, Ulrike; Ohana, Reut; Seitel, Alexander; Metzger, Jasmin; Ashery-Padan, Ruth; Meinzer, Hans-Peter; Gröne, Hermann-Josef; Izraeli, Shai; Krämer, Alwin

    2014-01-01

    Although most animal cells contain centrosomes, consisting of a pair of centrioles, their precise contribution to cell division and embryonic development is unclear. Genetic ablation of STIL, an essential component of the centriole replication machinery in mammalian cells, causes embryonic lethality in mice around mid gestation associated with defective Hedgehog signaling. Here, we describe, by focused ion beam scanning electron microscopy, that STIL(-/-) mouse embryos do not contain centrioles or primary cilia, suggesting that these organelles are not essential for mammalian development until mid gestation. We further show that the lack of primary cilia explains the absence of Hedgehog signaling in STIL(-/-) cells. Exogenous re-expression of STIL or STIL microcephaly mutants compatible with human survival, induced non-templated, de novo generation of centrioles in STIL(-/-) cells. Thus, while the abscence of centrioles is compatible with mammalian gastrulation, lack of centrioles and primary cilia impairs Hedgehog signaling and further embryonic development.

  19. Effect of automobile pollution on chlorophyll content of roadside urban trees

    M. Iqbal

    2015-09-01

    Full Text Available The effect of automobile pollution was determined on chlorophyll content of four different tree species viz. Azadirachta indica L., Conocarpus erectus L., Guiacum officinale L.and Eucalyptus sp. growing along the roads of the city.  Significant changes in the level of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” were found in the leaves of four tree species (A. indica, C. erectus, G.officinale and Eucalyptus sp. collected from polluted sites (Airport, Malir Halt, Quaidabad as compared to control site (Karachi University Campus. Lowest concentration of chlorophyll “a”, chlorophyll “b” and chlorophyll “a+b” was recorded in the leaf samples of all tree species collected from Quaidabad site when compared with the leaf samples collected from control site. The highest levels of chlorophyll pigment were recorded in all tree species leave samples collected from Karachi University Campus.  Similarly, better levels of chlorophyll “a”, chlorophyll “b” and total chlorophyll “a+b” was observed in all tree species growing at Airport site as compared to plants growing at Malir Halt and Quaidabad sites.  This study clearly indicated that the vehicular activities induced air pollution problem and affected on the level of chlorophyll pigments in trees which were exposed to road side pollution.

  20. Integrating Biology into the General Chemistry Laboratory: Fluorometric Analysis of Chlorophyll "a"

    Wesolowski, Meredith C.

    2014-01-01

    A laboratory experiment that introduces fluorometry of chlorophyll "a" at the general chemistry level is described. The use of thin-layer chromatography to isolate chlorophyll "a" from spirulina and leaf matter enables quantification of small amounts of chlorophyll "a" via fluorometry. Student results were reasonably…

  1. Qtl mapping of wheat doubled haploids for chlorophyll content and chlorophyll fluorescence kinetics under drought stress imposed at anthesis stage

    Ilyas, M.; Ilyas, N.; Arshad, M.; Kazi, A.G.

    2014-01-01

    Drought stress is one of the major environmental constraints to crop plants including wheat worldwide. Synthetic hexaploid can act as a vehicle for improving crop tolerance against biotic and abiotic stresses. Doubled haploid population consisting of one hundred and forty individuals derived from cross of Opata and SH223 was used in the present study to identify genomic regions associated with various quantitative attributes of physiological nature. Doubled haploid mapping population was phenotyped for chlorophyll content and chlorophyll fluorescence kinetics under control and drought stress imposed at anthesis stage. Genotyping of population was accomplished by utilizing two hundred and sixty one polymorphic Gaterslaben wheat microsatellites and Beltsville agriculture research center simple sequence repeats. Linkage map of doubled haploid population comprising of 19 linkage groups and covering map length of two thousands six hundred and twenty six (2626) cM was constructed using map maker software. Major and minor QTLs associated with quantitative traits were identified using QGene software. Major QTL for chlorophyll content (QTc.wwc-1B-S11) of doubled haploid mapping population under anthesis drought stress was mapped on chromosome 1B and explained 10.09 percent of phenotypic variation at LOD score of 5.5. Seven major and minor QTLs for PCFK of doubled haploids were identified on chromosome 1B, 7A and 7D under control and drought stress at anthesis stage. The identified QTLs are of prime importance for high resolution mapping in synthetic hexaploid wheat. Genomic synteny of doubled haploids was observed with rice chromosome 2, 4, 7 and maize chromosome 7 owing to occurrence of orthologous QTLs for chlorophyll content and chlorophyll fluorescence respectively. (author)

  2. Two-photon excited fluorescence from higher electronic states of chlorophylls in photosynthetic antenna complexes a new approach to detect strong excitonic chlorophyll a/b coupling

    Leupold, D; Ehlert, J; Irrgang, K D; Renger, G; Lokstein, H

    2002-01-01

    Stepwise two-photon excitation of chlorophyll a and b in the higher plant main light-harvesting complex (LHC II) and the minor complex CP29 (as well as in organic solution) with 100-fs pulses in the Q/sub y/ region results in a weak blue fluorescence. The dependence of the spectral shape of the blue fluorescence on excitation wavelength offers a new approach to elucidate the long-standing problem of the origin of spectral "chlorophyll forms" in pigment-protein complexes, in particular the characterization of chlorophyll a/b-heterodimers. As a first result we present evidence for the existence of strong chlorophyll a/b-interactions (excitonically coupled transitions at 650 and 680 nm) in LHC II at ambient temperature. In comparison with LHC II, the experiments with CP29 provide further evidence that the lowest energy chlorophyll a transition (at ~680 nm) is not excitonically coupled to chlorophyll b. (22 refs).

  3. Dead or Alive? Using Membrane Failure and Chlorophyll a Fluorescence to Predict Plant Mortality from Drought.

    Guadagno, Carmela R; Ewers, Brent E; Speckman, Heather N; Aston, Timothy Llewellyn; Huhn, Bridger J; DeVore, Stanley B; Ladwig, Joshua T; Strawn, Rachel N; Weinig, Cynthia

    2017-09-01

    Climate models predict widespread increases in both drought intensity and duration in the next decades. Although water deficiency is a significant determinant of plant survival, limited understanding of plant responses to extreme drought impedes forecasts of both forest and crop productivity under increasing aridity. Drought induces a suite of physiological responses; however, we lack an accurate mechanistic description of plant response to lethal drought that would improve predictive understanding of mortality under altered climate conditions. Here, proxies for leaf cellular damage, chlorophyll a fluorescence, and electrolyte leakage were directly associated with failure to recover from drought upon rewatering in Brassica rapa (genotype R500) and thus define the exact timing of drought-induced death. We validated our results using a second genotype (imb211) that differs substantially in life history traits. Our study demonstrates that whereas changes in carbon dynamics and water transport are critical indicators of drought stress, they can be unrelated to visible metrics of mortality, i.e. lack of meristematic activity and regrowth. In contrast, membrane failure at the cellular scale is the most proximate cause of death. This hypothesis was corroborated in two gymnosperms ( Picea engelmannii and Pinus contorta ) that experienced lethal water stress in the field and in laboratory conditions. We suggest that measurement of chlorophyll a fluorescence can be used to operationally define plant death arising from drought, and improved plant characterization can enhance surface model predictions of drought mortality and its consequences to ecosystem services at a global scale. © 2017 American Society of Plant Biologists. All Rights Reserved.

  4. The influence of gamma rays irradiation on chlorophyll mutation and genetic variability of agronomic characters in soybean plant

    Ratma, Rivaie; Sumargono, A.M. Riyanti

    1998-01-01

    Seeds of soybean mutant line No. 13/PsJ with 12% moisture content were irradiated by 0,10;0,20;0.30 and 0.40 kGy of gamma rays treatment. Number of irradiated seed for each treatment was 1500 seeds. Irradiated of seeds were planted in the 4m X 5m plot size with 0,20m x 0,40m spacing and two seed each hole and were planted as M-1 plants in the wet season of 1996/1997 at PAIR field experiment in Pasar Jumat, Jakarta. The experiment was designed Randomized Block Design with three replication Plans of M-1 generation were harvested individuality and were planted as known M2 plants in the next generation in dry season of 1997 at PAIR field experiment. Seven days planting the chlorophyll mutation of plants were recorded by Frydenberg method and the genetic variability of plant height, number of fertile pods and nodes were calculated by Singh and Chaudhary formula. Results of the experiment showed that chlorophyll mutation and genetic variability of plant height and number of fertile pods could be improved be 0.10 and 0,20 kGy of gamma rays treatment. (authors)

  5. Mutant power: using mutant allele collections for yeast functional genomics.

    Norman, Kaitlyn L; Kumar, Anuj

    2016-03-01

    The budding yeast has long served as a model eukaryote for the functional genomic analysis of highly conserved signaling pathways, cellular processes and mechanisms underlying human disease. The collection of reagents available for genomics in yeast is extensive, encompassing a growing diversity of mutant collections beyond gene deletion sets in the standard wild-type S288C genetic background. We review here three main types of mutant allele collections: transposon mutagen collections, essential gene collections and overexpression libraries. Each collection provides unique and identifiable alleles that can be utilized in genome-wide, high-throughput studies. These genomic reagents are particularly informative in identifying synthetic phenotypes and functions associated with essential genes, including those modeled most effectively in complex genetic backgrounds. Several examples of genomic studies in filamentous/pseudohyphal backgrounds are provided here to illustrate this point. Additionally, the limitations of each approach are examined. Collectively, these mutant allele collections in Saccharomyces cerevisiae and the related pathogenic yeast Candida albicans promise insights toward an advanced understanding of eukaryotic molecular and cellular biology. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. Are tyrosine residues involved in the photoconversion of the water-soluble chlorophyll-binding protein of Chenopodium album?

    Takahashi, S; Seki, Y; Uchida, A; Nakayama, K; Satoh, H

    2015-05-01

    Non-photosynthetic and hydrophilic chlorophyll (Chl) proteins, called water-soluble Chl-binding proteins (WSCPs), are distributed in various species of Chenopodiaceae, Amaranthaceae, Polygonaceae and Brassicaceae. Based on their photoconvertibility, WSCPs are categorised into two classes: Class I (photoconvertible) and Class II (non-photoconvertible). Chenopodium album WSCP (CaWSCP; Class I) is able to convert the chlorin skeleton of Chl a into a bacteriochlorin-like skeleton under light in the presence of molecular oxygen. Potassium iodide (KI) is a strong inhibitor of the photoconversion. Because KI attacks tyrosine residues in proteins, tyrosine residues in CaWSCP are considered to be important amino acid residues for the photoconversion. Recently, we identified the gene encoding CaWSCP and found that the mature region of CaWSCP contained four tyrosine residues: Tyr13, Tyr14, Tyr87 and Tyr134. To gain insight into the effect of the tyrosine residues on the photoconversion, we constructed 15 mutant proteins (Y13A, Y14A, Y87A, Y134A, Y13-14A, Y13-87A, Y13-134A, Y14-87A, Y14-134A, Y87-134A, Y13-14-87A, Y13-14-134A, Y13-87-134A, Y14-87-134A and Y13-14-87-134A) using site-directed mutagenesis. Amazingly, all the mutant proteins retained not only chlorophyll-binding activity, but also photoconvertibility. Furthermore, we found that KI strongly inhibited the photoconversion of Y13-14-87-134A. These findings indicated that the four tyrosine residues are not essential for the photoconversion. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  7. Repair-defective mutants of Alteromonas espejiana, the host for bacteriophage PM2

    Zerler, B.R.; Wallace, S.S.

    1984-01-01

    The in vivo repair processes of Alteromonas espejiana, the host for bacteriophage PM2, were characterized, and UV- and methyl methanesulfonate (MMS)-sensitive mutants were isolated. Wild-type A. espejiana cells were capable of photoreactivation, excision, recombination, and inducible repair. There was no detecttable pyrimidine dimer-DNA N-glycosylase activity, and pyrimidine dimer removal appeared to occur by a pathway analogous to the Escherichia coli Uvr pathway. The UV- and MMS-sensitive mutants of A. espejiana included three groups, each containing at least one mutation involved with excision, recombination, or inducible repair. One group that was UV sensitive but not sensitive to MMS or X rays showed a decreased ability to excise pyrimidine dimers. Mutants in this group were also sensitive to psoralen plus near-UV light and were phenotypically analogous to the E. coli uvr mutants. A second group was UV and MMS sensitive but not sensitive to X rays and appeared to contain mutations in a gene(s) involved in recombination repair. These recombination-deficient mutants differed from the E. coli rec mutants, which are MMS and X-ray sensitive. The third group of A. espejiana mutants was sensitive to UV, MMS, and X rays. These mutants were recombination deficient, lacked inducible repair, and were phenotypically similar to E. coli recA mutants

  8. Cylindrical aggregates of chlorophylls studied by small-angle neutron scatter

    Worcester, D.L. [Univ. of Missouri, Columbus, MO (United States); Katz, J.J. [Argonne National Laboratory, IL (United States)

    1994-12-31

    Neutron small-angle scattering has demonstrated tubular chlorophyll aggregates formed by self-assembly of a variety of chlorophyll types in nonpolar solvents. The size and other properties of the tubular aggregates can be accounted for by stereochemical properties of the chlorophyll molecules. Features of some of the structures are remarkably similar to light harvesting chlorophyll complexes in vivo, particularly for photosynthetic bacteria. These nanotube chlorophyll structures may have applications as light harvesting biomaterials where efficient energy transfer occurs from an excited state which is highly delocalized.

  9. Synthesis of chlorophyll-c derivatives by modifying natural chlorophyll-a.

    Xu, Meiyun; Kinoshita, Yusuke; Matsubara, Shogo; Tamiaki, Hitoshi

    2016-03-01

    Chlorophyll-a (Chl-a) was extracted from cyanobacterial cells and modified to methyl pyropheophorbide-a. The 3-vinyl-chlorin was transformed to zinc complex of the corresponding 3-acetyl-porphyrin. The zinc porphyrin was oxidized to give cis-7,8- and 17,18-dihydroxy-chlorins as well cis-7,8-cis-17,18-tetrahydroxybacteriochlorin. After zinc-demetallation, the isolated cis-7,8- and 17,18-diols were reduced at the 3-acetyl group and triply dehydrated under acidic conditions to afford two regioisomeric 3-vinyl-porphyrins, methyl divinyl-pyroprotopheophorbide-a possessing the 8-vinyl group and 17-propionate residue (one of the divinyl-protoChl-a derivatives) and methyl pyropheophorbide-c 1 possessing the 8-ethyl group and 17-acrylate residue (one of the Chl-c 1 derivatives), respectively. The resulting 7,8,17,18-tetrol was reduced and then acidically treated, giving five-fold dehydrated free base porphyrin, methyl pyropheophorbide-c 2 possessing the 3,8-divinyl groups and 17-acrylate residue (one of the Chl-c 2 derivatives). The visible absorption and fluorescence emission spectra of the three semi-synthetic 3-vinyl-porphyrins in dichloromethane were compared with those of the corresponding 8-ethyl-porphyrin bearing the 17-propionate residue, methyl pyroprotopheophorbide-a (one of the protoChl-a derivatives). The Soret and Qy absorption maxima were shifted to longer wavelengths with an increase of π-conjugation in a molecule: protoChl-a (8-CH2CH3/17-CH2CH2COOCH3) < divinyl-protoChl-a (8-CH=CH2/17-CH2CH2COOCH3) < Chl-c 1 (8-CH2CH3/17-CH=CHCOOCH3) < Chl-c 2 derivatives (8-CH=CH2/17-CH=CHCOOCH3). The 17(1),17(2)-dehydrogenation broadened the absorption bands. The emission maxima were bathochromically shifted in the same order. The reaction mechanism of the present dehydration indicates that the biosynthetic pathway of Chls-c would include the hydroxylation of the 17-propionate reside at the 17(1)-position and successive dehydration to the 17-acrylate residue.

  10. Multifractal analysis of oceanic chlorophyll maps remotely sensed from space

    L. de Montera

    2011-03-01

    Full Text Available Phytoplankton patchiness has been investigated with multifractal analysis techniques. We analyzed oceanic chlorophyll maps, measured by the SeaWiFS orbiting sensor, which are considered to be good proxies for phytoplankton. The study area is the Senegalo-Mauritanian upwelling region, because it has a low cloud cover and high chlorophyll concentrations. Multifractal properties are observed, from the sub-mesoscale up to the mesoscale, and are found to be consistent with the Corssin-Obukhov scale law of passive scalars. This result indicates that, in this specific region and within this scale range, turbulent mixing would be the dominant effect leading to the observed variability of phytoplankton fields. Finally, it is shown that multifractal patchiness can be responsible for significant biases in the nonlinear source and sink terms involved in biogeochemical numerical models.

  11. Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes

    Filstrup, Christopher T.; Wagner, Tyler; Soranno, Patricia A.; Stanley, Emily H.; Stow, Craig A.; Webster, Katherine E.; Downing, John A.

    2014-01-01

    The relationship between chlorophyll a (Chl a) and total phosphorus (TP) is a fundamental relationship in lakes that reflects multiple aspects of ecosystem function and is also used in the regulation and management of inland waters. The exact form of this relationship has substantial implications on its meaning and its use. We assembled a spatially extensive data set to examine whether nonlinear models are a better fit for Chl a—TP relationships than traditional log-linear models, whether there were regional differences in the form of the relationships, and, if so, which regional factors were related to these differences. We analyzed a data set from 2105 temperate lakes across 35 ecoregions by fitting and comparing two different nonlinear models and one log-linear model. The two nonlinear models fit the data better than the log-linear model. In addition, the parameters for the best-fitting model varied among regions: the maximum and lower Chl aasymptotes were positively and negatively related to percent regional pasture land use, respectively, and the rate at which chlorophyll increased with TP was negatively related to percent regional wetland cover. Lakes in regions with more pasture fields had higher maximum chlorophyll concentrations at high TP concentrations but lower minimum chlorophyll concentrations at low TP concentrations. Lakes in regions with less wetland cover showed a steeper Chl a—TP relationship than wetland-rich regions. Interpretation of Chl a—TP relationships depends on regional differences, and theory and management based on a monolithic relationship may be inaccurate.

  12. [Vegetation index estimation by chlorophyll content of grassland based on spectral analysis].

    Xiao, Han; Chen, Xiu-Wan; Yang, Zhen-Yu; Li, Huai-Yu; Zhu, Han

    2014-11-01

    Comparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes the measured reflectance spectral curve and its first derivative curve in the grasslands of Songpan, Sichuan and Gongger, Inner Mongolia, conducts correlation analysis between these two spectral curves and chlorophyll content, and finds out the regulation between REP (red edge position) and grassland chlorophyll content, that is, the higher the chlorophyll content is, the higher the REIP (red-edge inflection point) value would be. Then, this paper constructs GCI (grassland chlorophyll index) and selects the most suitable band for retrieval. Finally, this paper calculates the GCI by the use of satellite hyperspectral image, conducts the verification and accuracy analysis of the calculation results compared with chlorophyll content data collected from field of twice experiments. The result shows that for grassland chlorophyll content, GCI has stronger sensitivity than other indices of chlorophyll, and has higher estimation accuracy. GCI is the first proposed to estimate the grassland chlorophyll content, and has wide application potential for the remote sensing retrieval of grassland chlorophyll content. In addition, the grassland chlorophyll content estimation method based on remote sensing retrieval in this paper provides new research ideas for other vegetation biochemical parameters' estimation, vegetation growth status' evaluation and grassland ecological environment change's monitoring.

  13. Estimate of Leaf Chlorophyll and Nitrogen Content in Asian Pear (Pyrus serotina Rehd. by CCM-200

    Mostafa GHASEMI

    2011-03-01

    Full Text Available In many cases evaluation of chlorophyll and nitrogen content in plants need to destructive methods, more time and organic solvents. Application of chlorophyll meters save time and resources. The aim of this study was estimating of chlorophyll and nitrogen content in Asian pear leaves using non-destructive method and rapid quantification of chlorophyll by chlorophyll content meter (CCM-200. This study was conducted on 8 years old Asian pear trees during June 2008 in Tehran, Iran. To develop our regression model, the chlorophyll meter data were correlated with extracted chlorophyll and nitrogen content data obtained from DMSO and Kejeldal methods, respectively. The results showed that, there was positive and linear correlation between CCM-200 data and chlorophyll a (R�=0.7183, chlorophyll b (R�=0.8523, total chlorophyll (R�=0.90, and total nitrogen content (R�=0.76 in Asian pear leaves. Thus, it can be concluded that, CCM-200 can be used in order to predict both chlorophyll and nitrogen content in Asian pear leaves.

  14. Mutant genes in pea breeding

    Swiecicki, W.K.

    1990-01-01

    Full text: Mutations of genes Dpo (dehiscing pods) and A (anthocyanin synthesis) played a role in pea domestication. A number of other genes were important in cultivar development for 3 types of usage (dry seeds, green vegetable types, fodder), e.g. fn, fna, le, p, v, fas and af. New genes (induced and spontaneous), are important for present ideotypes and are registered by the Pisum Genetics Association (PGA). Comparison of a pea variety ideotype with the variation available in gene banks shows that breeders need 'new' features. In mutation induction experiments, genotype, mutagen and method of treatment (e.g. combined or fractionated doses) are varied for broadening the mutation spectrum and selecting more genes of agronomic value. New genes are genetically analysed. In Poland, some mutant varieties with the gene afila were registered, controlling lodging by a shorter stem and a higher number of internodes. Really non-lodging pea varieties could strongly increase seed yield. But the probability of detecting a major gene for lodging resistance is low. Therefore, mutant genes with smaller influence on plant architecture are sought, to combine their effect by crossing. Promising seem to be the genes rogue, reductus and arthritic as well as a number of mutant genes not yet genetically identified. The gene det for terminal inflorescence - similarly to Vicia faba - changes plant development. Utilisation of assimilates and ripening should be better. Improvement of harvest index should give higher seed yield. A number of genes controlling disease resistance are well known (eg. Fw, Fnw, En, mo and sbm). Important in mass screening of resistance are closely linked gene markers. Pea gene banks collect respective lines, but mutants induced in highly productive cultivars would be better. Inducing gene markers sometimes seems to be easier than transfer by crossing. Mutation induction in pea breeding is probably more important because a high number of monogenic features are

  15. Notes on the instability of extracted chlorophyll and a reported effect of ozone on lichen algae

    Brown, D H

    1980-01-01

    Recently Rosentreter and Ahmadjian reported on the effects of ozone on the chlorophyll content of Cladonia arbuscula and isolated Trebouxia cells. However, the chlorophyll data they presented, even for the control, unozone-treated material, appears to be unusual. They reported values of the chlorophyll a/b ratio of 0.308-0.463 from Cladonia arbuscula and 0.345-0.476 for Trebouxia which are substantially lower than other published values. Because chlorophyll b is normally present in green plants as a minor accessory photosynthetic pigment, the suggestion that it was the major chlorophyll component requires some explanation. The purpose of this study is to show that chlorophyll is unstable when extracted into methanol and to suggest that the extraction and storage conditions used by Rosentreter and Ahmadjian may have allowed pigment degradation to occur which thereby accounted for the low chlorophyll a/b ratios they obtained.

  16. Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

    Karina Gonçalves da Silva

    2017-10-01

    Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

  17. Antigenicity of Leishmania-Activated C-Kinase Antigen (LACK in Human Peripheral Blood Mononuclear Cells, and Protective Effect of Prime-Boost Vaccination With pCI-neo-LACK Plus Attenuated LACK-Expressing Vaccinia Viruses in Hamsters

    Laura Fernández

    2018-04-01

    Full Text Available Leishmania-activated C-kinase antigen (LACK is a highly conserved protein among Leishmania species and is considered a viable vaccine candidate for human leishmaniasis. In animal models, prime-boost vaccination with LACK-expressing plasmids plus attenuated vaccinia viruses (modified vaccinia Ankara [MVA] and mutant M65 expressing LACK, has been shown to protect against cutaneous leishmaniasis (CL. Further, LACK demonstrated to induce the production of protective cytokines in patients with active CL or cured visceral leishmaniasis, as well as in asymptomatic individuals from endemic areas. However, whether LACK is capable to trigger cytokine release by peripheral blood mononuclear cells from patients cured of CL due to Leishmania infantum (L. infantum or induce protection in L. infantum-infected hamsters [visceral leishmaniasis (VL model], has not yet been analyzed. The present work examines the ex vivo immunogenicity of LACK in cured VL and CL patients, and asymptomatic subjects from an L. infantum area. It also evaluates the vaccine potential of LACK against L. infantum infection in hamsters, in a protocol of priming with plasmid pCI-neo-LACK (DNA-LACK followed by a booster with the poxvirus vectors MVA-LACK or M65-LACK. LACK-stimulated PBMC from both asymptomatic and cured subjects responded by producing IFN-γ, TNF-α, and granzyme B (Th1-type response. Further, 78% of PBMC samples that responded to soluble Leishmania antigen showed IFN-γ secretion following stimulation with LACK. In hamsters, the protocol of DNA-LACK prime/MVA-LACK or M65-LACK virus boost vaccination significantly reduced the amount of Leishmania DNA in the liver and bone marrow, with no differences recorded between the use of MVA or M65 virus vector options. In summary, the Th1-type and cytotoxic responses elicited by LACK in PBMC from human subjects infected with L. infantum, and the parasite protective effect of prime/boost vaccination in hamsters with DNA-LACK/MVA-LACK

  18. An extra early mutant of pigeonpea

    Ravikesavan, R.; Kalaimagal, T.; Rathnaswamy, R.

    2001-01-01

    The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M 2 to M 4 generation. In the M 4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

  19. Problem-Solving Test: Tryptophan Operon Mutants

    Szeberenyi, Jozsef

    2010-01-01

    This paper presents a problem-solving test that deals with the regulation of the "trp" operon of "Escherichia coli." Two mutants of this operon are described: in mutant A, the operator region of the operon carries a point mutation so that it is unable to carry out its function; mutant B expresses a "trp" repressor protein unable to bind…

  20. A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

    Meier, Stuart; Tzfadia, Oren; Vallabhaneni, Ratnakar; Gehring, Christoph A; Wurtzel, Eleanore T

    2011-01-01

    Background: The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana.Results: A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR) but was inhibited by abscisic acid (ABA). Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs) and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced and uncoupled from that of

  1. A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

    Meier, Stuart

    2011-05-19

    Background: The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana.Results: A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR) but was inhibited by abscisic acid (ABA). Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs) and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced and uncoupled from that of

  2. A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

    Vallabhaneni Ratnakar

    2011-05-01

    Full Text Available Abstract Background The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana. Results A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR but was inhibited by abscisic acid (ABA. Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced

  3. Mutation techniques in sesame (Sesamum indicum L.) for intensive management: confirmed mutants

    Cagirgan, M.I.

    2001-01-01

    Seeds of four sesame cultivars, Muganli-57, Oezberk-82, Camdibi and Goelmarmara were irradiated in the range of 150-750 Gy doses of gamma rays in three different experiments. Irradiated seeds with their controls were sown in 1994, 1995 and 1997 to grow M 1 . Three different harvesting procedures were applied to the M 1 populations, i.e., plant harvesting, branch harvesting and bulk harvesting. M 2 generations, therefore, were both grown as progeny rows and bulk populations. Potential mutants fitting the breeding objectives were selected after careful screening during the growing period; there were mutations for closed capsule, determinate growth habit, wilting tolerance, chlorophyll deficiency, hairy capsule and multicarpelate, sterility as well as in quantitative traits such as flowering time, capsule size, plant height. In M 3 , the selected mutants with their normal looking sibs from the same progeny were grown again to confirm mutant traits in progeny rows of 2 meters length and 40 cm apart. After emergence, the plants within a row were thinned to 5 cm apart. Normal agronomic practices were applied to the nurseries. It was finally concluded that recovering unique induced mutants, such as closed capsules, is not a matter of ''luck'' but the result of growing large M 2 populations, preferably in plant progeny rows, and careful screening. (author)

  4. STAY-GREEN and Chlorophyll Catabolic Enzymes Interact at Light-Harvesting Complex II for Chlorophyll Detoxification during Leaf Senescence in Arabidopsis[C][W

    Sakuraba, Yasuhito; Schelbert, Silvia; Park, So-Yon; Han, Su-Hyun; Lee, Byoung-Doo; Andrès, Céline Besagni; Kessler, Felix; Hörtensteiner, Stefan; Paek, Nam-Chon

    2012-01-01

    During leaf senescence, plants degrade chlorophyll to colorless linear tetrapyrroles that are stored in the vacuole of senescing cells. The early steps of chlorophyll breakdown occur in plastids. To date, five chlorophyll catabolic enzymes (CCEs), NONYELLOW COLORING1 (NYC1), NYC1-LIKE, pheophytinase, pheophorbide a oxygenase (PAO), and red chlorophyll catabolite reductase, have been identified; these enzymes catalyze the stepwise degradation of chlorophyll to a fluorescent intermediate, pFCC, which is then exported from the plastid. In addition, STAY-GREEN (SGR), Mendel’s green cotyledon gene encoding a chloroplast protein, is required for the initiation of chlorophyll breakdown in plastids. Senescence-induced SGR binds to light-harvesting complex II (LHCII), but its exact role remains elusive. Here, we show that all five CCEs also specifically interact with LHCII. In addition, SGR and CCEs interact directly or indirectly with each other at LHCII, and SGR is essential for recruiting CCEs in senescing chloroplasts. PAO, which had been attributed to the inner envelope, is found to localize in the thylakoid membrane. These data indicate a predominant role for the SGR-CCE-LHCII protein interaction in the breakdown of LHCII-located chlorophyll, likely to allow metabolic channeling of phototoxic chlorophyll breakdown intermediates upstream of nontoxic pFCC. PMID:22366162

  5. Abnormal grooming activity in Dab1(scm) (scrambler) mutant mice.

    Strazielle, C; Lefevre, A; Jacquelin, C; Lalonde, R

    2012-07-15

    Dab1(scm) mutant mice, characterized by cell ectopias and degeneration in cerebellum, hippocampus, and neocortex, were compared to non-ataxic controls for different facets of grooming caused by brief water immersions, as well as some non-grooming behaviors. Dab1(scm) mutants were strongly affected in their quantitative functional parameters, exhibiting higher starting latencies before grooming relative to non-ataxic littermates of the A/A strain, fewer grooming bouts, and grooming components of shorter duration, with an unequal regional distribution targeting almost totally the rostral part (head washing and forelimb licking) of the animal. Only bouts of a single grooming element were preserved. The cephalocaudal order of grooming elements appeared less disorganized, mutant and control mice initiating the grooming with head washing and forelimb licking prior to licking posterior parts. However, mutants differed from controls in that all their bouts were incomplete but uninterrupted, although intergroup difference for percentage of the incorrect transitions was not significant. In contrast to grooming, Dab1(scm) mice ambulated for a longer time. During walking episodes, they exhibited more body scratching than controls, possibly to compensate for the lack of licking different body parts. In conjunction with studies with other ataxic mice, these results indicate that the cerebellar cortex affects grooming activity and is consequently involved in executing various components, but not in its sequential organization, which requires other brain regions such as cerebral cortices or basal ganglia. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Dwarf mutant of rice variety Seratus Malam

    Mugiono, P. S.; Soemanggono, A.M.R.

    1989-01-01

    Full text: Seeds of 'Seratus Malam', a local tall upland variety with long panicles and high yield potential were irradiated with 10-50 krad gamma rays in 1983. From 50,000 M 2 plants, 130 semidwarf mutants and 1 dwarf mutant were selected. The dwarf mutant M-362 was obtained from the 10 krad treatment. The mutant shows about 50% reduction in plant height, but also in number of productive tillers. Thus the yield per plant is also significantly less. However, the mutant gene is not allelic to DGWG and therefore may be useful in cross breeding. (author)

  7. [Estimation of forest canopy chlorophyll content based on PROSPECT and SAIL models].

    Yang, Xi-guang; Fan, Wen-yi; Yu, Ying

    2010-11-01

    The forest canopy chlorophyll content directly reflects the health and stress of forest. The accurate estimation of the forest canopy chlorophyll content is a significant foundation for researching forest ecosystem cycle models. In the present paper, the inversion of the forest canopy chlorophyll content was based on PROSPECT and SAIL models from the physical mechanism angle. First, leaf spectrum and canopy spectrum were simulated by PROSPECT and SAIL models respectively. And leaf chlorophyll content look-up-table was established for leaf chlorophyll content retrieval. Then leaf chlorophyll content was converted into canopy chlorophyll content by Leaf Area Index (LAD). Finally, canopy chlorophyll content was estimated from Hyperion image. The results indicated that the main effect bands of chlorophyll content were 400-900 nm, the simulation of leaf and canopy spectrum by PROSPECT and SAIL models fit better with the measured spectrum with 7.06% and 16.49% relative error respectively, the RMSE of LAI inversion was 0. 542 6 and the forest canopy chlorophyll content was estimated better by PROSPECT and SAIL models with precision = 77.02%.

  8. Cytotoxicity and Phototoxicity of Chlorophyll a/Hydroxypropyl-γ-cyclodextrin Complex on Leishmania Major Promastigotes

    Azam Jafari Parizi

    2011-06-01

    Full Text Available Introduction: Cutaneous leishmaniasis (CL is a widespread disease that is epidemic in Iran, too. Photodynamic therapy (PDT is an attractive modality to treat cancer and hyper proliferative diseases based on the use of a photosensitizer in the presence of oxygen and proper wavelength of light. In consideration of lesion location, lack of systemic involvement and inefficiency of current treatments, nowadays this modality is purposed for treating Leishmaniasis. In this paper, efficacy of PDT using a natural dye (chlorophyll a on Leishmania major promastigotes is reported. Material and Methods: The experiments was done on Leishmania major parasites (MRHO/IR/75/ER in the presence of Chlorophyll a /Hydroxypropyl-γ-cyclodextrin(chl a/CD complex as a photosensitizer. At first, dye uptake by promastigotes was evaluated via fluorimetric assessments after different incubation periods. Then dye cytotoxicity was evaluated at different concentration after 24 h incubation. Finally PDT experiments were designed with two doses of light and 10 µM of photosensitizer. Considering all possible controls, the percentage of the parasite survival at 24 hours post treatment was assessed by MTS method. All experiments were repeated at least three times. Results: On the basis of the dye uptake data, 24h was considered for incubating of photosensitizer with promastigotes. IC50 of chl a/CD complex was about 42.6 µM. After parasites irradiation by light at 248 j/cm2, more than 50% of cell death was recorded that is significant in comparing with similar groups without dye, without light, and lower dose of light. In these conditions, ED50 of PDT on promastigotes is determined nearly 246 J/cm2. Discussion and Conclusion: Considering low cytotoxicity in darkness and adequate phototoxicity of chl a/CD complex in comparison with other photosensitizers such as AlPhtalocyanine chloride, it can be introduced as a promising candidate for futher use in PDT experiments on amastigotes

  9. Prospects for Chlorophyll Fluorescence Remote Sensing from the Orbiting Carbon Observatory-2

    Frankenberg, Christian; Odell, Chris; Berry, Joseph; Guanter, Luis; Joiner, Joanna; Kohler, Philipp; Pollock, Randy; Taylor, Thomas E.

    2014-01-01

    The Orbiting Carbon Observatory-2 (OCO-2), scheduled to launch in July 2014, is a NASA mission designed to measure atmospheric CO2. Its main purpose is to allow inversions of net flux estimates of CO2 on regional to continental scales using the total column CO2 retrieved using high-resolution spectra in the 0.76, 1.6, and 2.0 nm ranges. Recently, it was shown that solar-induced chlorophyll fluorescence (SIF), a proxy for gross primary production (GPP, carbon uptake through photosynthesis), can be accurately retrieved from space using high spectral resolution radiances in the 750 nm range from the Japanese GOSAT and European GOME-2 instruments. Here, we use real OCO-2 thermal vacuum test data as well as a full repeat cycle (16 days) of simulated OCO-2 spectra under realistic conditions to evaluate the potential of OCO-2 for retrievals of chlorophyll fluorescence and also its dependence on clouds and aerosols. We find that the single-measurement precision is 0.3-0.5 Wm(exp -2)sr(exp -1) nm(exp -1) (15-25% of typical peak values), better than current measurements from space but still difficult to interpret on a single-sounding basis. The most significant advancement will come from smaller ground-pixel sizes and increased measurement frequency, with a 100-fold increase compared to GOSAT (and about 8 times higher than GOME-2). This will largely decrease the need for coarse spatial and temporal averaging in data analysis and pave the way to accurate local studies.We also find that the lack of full global mapping from the OCO-2 only incurs small representativeness errors on regional averages. Eventually, the combination of net ecosystem exchange (NEE) derived from CO2 source/sink inversions and SIF as proxy for GPP from the same satellite will provide a more process-based understanding of the global carbon cycle.

  10. Genetic background of Prop1(df) mutants provides remarkable protection against hypothyroidism-induced hearing impairment.

    Fang, Qing; Giordimaina, Alicia M; Dolan, David F; Camper, Sally A; Mustapha, Mirna

    2012-04-01

    Hypothyroidism is a cause of genetic and environmentally induced deafness. The sensitivity of cochlear development and function to thyroid hormone (TH) mandates understanding TH action in this sensory organ. Prop1(df) and Pou1f1(dw) mutant mice carry mutations in different pituitary transcription factors, each resulting in pituitary thyrotropin deficiency. Despite the same lack of detectable serum TH, these mutants have very different hearing abilities: Prop1(df) mutants are mildly affected, while Pou1f1(dw) mutants are completely deaf. Genetic studies show that this difference is attributable to the genetic backgrounds. Using embryo transfer, we discovered that factors intrinsic to the fetus are the major contributor to this difference, not maternal effects. We analyzed Prop1(df) mutants to identify processes in cochlear development that are disrupted in other hypothyroid animal models but protected in Prop1(df) mutants by the genetic background. The development of outer hair cell (OHC) function is delayed, but Prestin and KCNQ4 immunostaining appear normal in mature Prop1(df) mutants. The endocochlear potential and KCNJ10 immunostaining in the stria vascularis are indistinguishable from wild type, and no differences in neurofilament or synaptophysin staining are evident in Prop1(df) mutants. The synaptic vesicle protein otoferlin normally shifts expression from OHC to IHC as temporary afferent fibers beneath the OHC regress postnatally. Prop1(df) mutants exhibit persistent, abnormal expression of otoferlin in apical OHC, suggesting delayed maturation of synaptic function. Thus, the genetic background of Prop1(df) mutants is remarkably protective for most functions affected in other hypothyroid mice. The Prop1(df) mutant is an attractive model for identifying the genes that protect against deafness.

  11. Isolation and characterization of mutant strains of Escherichia coli altered in H2 metabolism

    Lee, J.H.; Patel, P.; Sankar, P.; Shanmugam, K.T.

    1985-01-01

    A positive selection procedure is described for the isolation of hydrogenase-defective mutant strains of Escherichia coli. Mutant strains isolated by this procedure can be divided into two major classes. Class II mutants produced hydrogenase activity (determined by using a tritium-exchange assay) and formate hydrogenlyase activity but lacked the ability to reduce benzyl viologen or fumarate with H 2 as the electron donor. Class I mutants failed to produce active hydrogenase and hydrogenase-dependent activities. All the mutant strains produced detectable levels of formate dehydrogenase-1 and -2 and fumarate reductase. The mutation in class I mutants mapped near 65 min of the E. coli chromosome, whereas the mutation in class II mutants mapped between srl and cys operons (58 and 59 min, respectively) in the genome. The class II Hyd mutants can be further subdivided into two groups (hydA and hydB) based on the cotransduction characteristics with cys and srl. These results indicate that there are two hyd operons and one hup operon in the E. coli chromosome. The two hyd operons are needed for the production of active hydrogenase, and all three are essential for hydrogen-dependent growth of the cell

  12. PNRI mutant variety: Cordyline 'Afable'

    Aurigue, Fernando B.

    2012-01-01

    Cordyline 'Afable', registered by the Philippine Nuclear Research Institute as NSIC 2009 Or-83, is an induced mutant developed from Cordyline 'Kiwi' by treating stem cuttings with acute gamma radiation from a Cobalt-60 source. The new mutant is identical to Cordyline 'Kiwi' in growth habit but differs in foliage color, and exhibits field resistance to Phytophthora sp., a fungus that causes leaf blight and rot in Ti plants. Results of this mutation breeding experiment showed that leaf color was altered by gamma irradiation and resistance to fungal diseases was improved. It also demonstrated how mutations that occur in nature may be generated artificially. Propagation of cordyline 'Afable' is true-to-type by vegetative propagation methods, such as separation of suckers and offshoots, shoot tip cutting, and top cutting. Aside from landscaping material, terrarium or dish-garden plant, it is ideal as containerized plant for indoor and outdoor use. The leaves or shoots may be harvested as cut foliage for flower arrangements. (author)

  13. Oceanic turbidity and chlorophyll as inferred from ERTS-1 observations

    Curran, R. J.

    1973-01-01

    Spectral signatures of phytoplankton and other obscuring effects are considered in order to determine how to best use satellite data. The results of this study were then used to analyze the spectral data obtained from the ERTS-1 multispectral scanner (MSS). The analyzed satellite data were finally compared with surface ship measurements of chlorophyll concentration. It was found that the effects of water turbidity on the multispectral imagery can be discriminated by rationing the two shortest wavelength channels so that the effect of phytoplankton is enhanced.

  14. Influence of water-based ferrofluid upon chlorophylls in cereals

    Racuciu, Mihaela [Lucian Blaga University, Faculty of Science, 10 Blvd. Victoriei, Sibiu, 550012 (Romania)]. E-mail: mracuciu@yahoo.com; Creanga, Dorina-Emilia [Al. I. Cuza University, Faculty of Physics, 11A Blvd.Copou, Iasi, 700506 (Romania)

    2007-04-15

    The present experimental investigation was focused on the study of the simultaneous influence of the water-based ferrofluid and static magnetic field exposure on young cereal plants. Water-based ferrofluid, stabilized with citric acid was added daily in various concentrations, ranging between 10 and 250 {mu}L/L, in the culture medium of maize (Zea mays) plants in their early ontogenetic stages. The used static magnetic field was about 50 mT. In order to investigate the biochemical changes of chlorophylls and total carotenoids, spectrophotometric measurements were carried out, that revealed stimulatory effects of ferrofluid and magnetic exposure upon the studied plant species.

  15. Influence of water-based ferrofluid upon chlorophylls in cereals

    Racuciu, Mihaela; Creanga, Dorina-Emilia

    2007-01-01

    The present experimental investigation was focused on the study of the simultaneous influence of the water-based ferrofluid and static magnetic field exposure on young cereal plants. Water-based ferrofluid, stabilized with citric acid was added daily in various concentrations, ranging between 10 and 250 μL/L, in the culture medium of maize (Zea mays) plants in their early ontogenetic stages. The used static magnetic field was about 50 mT. In order to investigate the biochemical changes of chlorophylls and total carotenoids, spectrophotometric measurements were carried out, that revealed stimulatory effects of ferrofluid and magnetic exposure upon the studied plant species

  16. Simple heterogeneity parametrization for sea surface temperature and chlorophyll

    Skákala, Jozef; Smyth, Timothy J.

    2016-06-01

    Using satellite maps this paper offers a complex analysis of chlorophyll & SST heterogeneity in the shelf seas around the southwest of the UK. The heterogeneity scaling follows a simple power law and is consequently parametrized by two parameters. It is shown that in most cases these two parameters vary only relatively little with time. The paper offers a detailed comparison of field heterogeneity between different regions. How much heterogeneity is in each region preserved in the annual median data is also determined. The paper explicitly demonstrates how one can use these results to calculate representative measurement area for in situ networks.

  17. Role of chlorophylls, amino acids and sugars in tea

    Dev Choudhury, M.N.

    1980-01-01

    Plucked tea shoots from clones of different varieties of tea were withered, rolled, fermented and fired by CTC and orthodox methods of manufacture. Quantitative changes in the levels of chlorophylls, amino acids and water soluble sugars during different stages of processing of tea and also changes in the contents of their degradation products were studied by feeding 14 C-labelled phenylalanine, glucose, sodium carbonate and sodium propionate to the excised shoots and subsequently analysing the products. Results are discussed and suggestions have been made about adjusting the conditions of manufacture so that the teas with desired chemical constituents are produced. (M.G.B.)

  18. Gamma ray induced mutants in Coleus

    Vasudevan, K.; Jos, J.S.

    1988-01-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M 1 V 1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m 2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

  19. Gamma ray induced mutants in Coleus

    Vasudevan, K; Jos, J S [Central Tuber Crops Research Institute, Trivandrum, Kerala (India)

    1988-07-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M{sub 1}V{sub 1} generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m{sup 2} area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing.

  20. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock

    Tao Li

    2016-09-01

    Full Text Available Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

  1. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-01-01

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel. PMID:27618070

  2. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock.

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-09-07

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

  3. Sharing mutants and experimental information prepublication using FgMutantDb (https://scabusa.org/FgMutantDb).

    Baldwin, Thomas T; Basenko, Evelina; Harb, Omar; Brown, Neil A; Urban, Martin; Hammond-Kosack, Kim E; Bregitzer, Phil P

    2018-06-01

    There is no comprehensive storage for generated mutants of Fusarium graminearum or data associated with these mutants. Instead, researchers relied on several independent and non-integrated databases. FgMutantDb was designed as a simple spreadsheet that is accessible globally on the web that will function as a centralized source of information on F. graminearum mutants. FgMutantDb aids in the maintenance and sharing of mutants within a research community. It will serve also as a platform for disseminating prepublication results as well as negative results that often go unreported. Additionally, the highly curated information on mutants in FgMutantDb will be shared with other databases (FungiDB, Ensembl, PhytoPath, and PHI-base) through updating reports. Here we describe the creation and potential usefulness of FgMutantDb to the F. graminearum research community, and provide a tutorial on its use. This type of database could be easily emulated for other fungal species. Published by Elsevier Inc.

  4. Time-resolved interaction investigations of carbocyanine dyes and chlorophyll a in solution

    Feller, K.H.; Fassler, D.

    1983-01-01

    Using a Nd:YAG laser/streak camera system of 30 ps time resolution the quenching of the fluorescence of the carbocyanine dye ICC by chlorophyll a in methanolic solution was investigated. The fluorescence lifetime of ICC decreased within the chlorophyll concentration range 0 - 9x10 - 5 mol/l from 170 ps to 135 ps. The observed very effective fluorescence quenching process suggests that the formation of heteroaggregates from ICC and chlorophyll is responsible for the rapid energy transfer. (author)

  5. Chlorophyll metabolism in pollinated vs. parthenocarpic fig fruits throughout development and ripening.

    Rosianskey, Yogev; Dahan, Yardena; Yadav, Sharawan; Freiman, Zohar E; Milo-Cochavi, Shira; Kerem, Zohar; Eyal, Yoram; Flaishman, Moshe A

    2016-08-01

    Expression of 13 genes encoding chlorophyll biosynthesis and degradation was evaluated. Chlorophyll degradation was differentially regulated in pollinated and parthenocarpic fig fruits, leading to earlier chlorophyll degradation in parthenocarpic fruits. Varieties of the common fig typically yield a commercial summer crop that requires no pollination, although it can be pollinated. Fig fruit pollination results in larger fruit size, greener skin and darker interior inflorescence color, and slows the ripening process compared to non-pollinated fruits. We evaluated the effect of pollination on chlorophyll content and levels of transcripts encoding enzymes of the chlorophyll metabolism in fruits of the common fig 'Brown Turkey'. We cloned and evaluated the expression of 13 different genes. All 13 genes showed high expression in the fruit skin, inflorescences and leaves, but extremely low expression in roots. Pollination delayed chlorophyll breakdown in the ripening fruit skin and inflorescences. This was correlated with the expression of genes encoding enzymes in the chlorophyll biosynthesis and degradation pathways. Expression of pheophorbide a oxygenase (PAO) was strongly negatively correlated with chlorophyll levels during ripening in pollinated fruits; along with its high expression levels in yellow leaves, this supports a pivotal role for PAO in chlorophyll degradation in figs. Normalizing expression levels of all chlorophyll metabolism genes in the pollinated and parthenocarpic fruit skin and inflorescences showed three synthesis (FcGluTR1, FcGluTR2 and FcCLS1) and three degradation (FcCLH1, FcCLH2 and FcRCCR1) genes with different temporal expression in the pollinated vs. parthenocarpic fruit skin and inflorescences. FcCAO also showed different expressions in the parthenocarpic fruit skin. Thus, chlorophyll degradation is differentially regulated in the pollinated and parthenocarpic fruit skin and inflorescences, leading to earlier and more sustained

  6. N-glycan maturation mutants in Lotus japonicus for basic and applied glycoprotein research

    Pedersen, Carina T.; Loke, Ian; Lorentzen, Andrea

    2017-01-01

    Studies of protein N-glycosylation are important for answering fundamental questions on the diverse functions of glycoproteins in plant growth and development. Here we generated and characterised a comprehensive collection of Lotus japonicusLORE1 insertion mutants, each lacking the activity of one...... in the target glyco-genes. For example, both mass spectrometry and immunoblotting experiments suggest that proteins derived from the α1,3-fucosyltransferase (Lj3fuct) mutant completely lacked α1,3-core fucosylation. Mass spectrometry also suggested that the Lotus japonicus convicilin 2 was one of the main...

  7. Rapid assessment of water pollution by airborne measurement of chlorophyll content.

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1971-01-01

    Present techniques of airborne chlorophyll measurement are discussed as an approach to water pollution assessment. The differential radiometer, the chlorophyll correlation radiometer, and an infrared radiometer for water temperature measurements are described as the key components of the equipment. Also covered are flight missions carried out to evaluate the capability of the chlorophyll correlation radiometer in measuring the chlorophyll content in water bodies with widely different levels of nutrients, such as fresh-water lakes of high and low eutrophic levels, marine waters of high and low productivity, and an estuary with a high sediment content. The feasibility and usefulness of these techniques are indicated.

  8. Effect of gamma radiation on chlorophylls contents, net photosynthesis and respiration of chlorella pyrenoidosa

    Fernandez Gonzalez, J.; Martin Moreno, C.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first 'b' chlorophyll affected to a greater extent than 'a' chlorophyll. Net photosynthesis and respiration decline throughout the time of the observations after irradiation, this depressing effect being much more remarkable for the first one. Net photosynthesis inhibition levels of about 30% have got only five hours post irradiation at a dose of 5000 Gy. (author)

  9. Chlorophyll bleaching by UV-irradiation in vitro and in situ: Absorption and fluorescence studies

    Zvezdanovic, Jelena; Cvetic, Tijana; Veljovic-Jovanovic, Sonja; Markovic, Dejan

    2009-01-01

    Chlorophyll bleaching by UV-irradiation has been studied by absorbance and fluorescence spectroscopy in extracts containing mixtures of photosynthetic pigments, in acetone and n-hexane solutions, and in aqueous thylakoid suspensions. Chlorophyll undergoes destruction (bleaching) accompanied by fluorescent transient formation obeying first-order kinetics. The bleaching is governed by UV-photon energy input, as well as by different chlorophyll molecular organizations in solvents of different polarities (in vitro), and in thylakoids (in situ). UV-C-induced bleaching of chlorophylls in thylakoids is probably caused by different mechanisms compared to UV-A- and UV-B-induced bleaching

  10. The effects of heavy metal ions on the chlorophyll content and cell membrane permeability of charophytes

    Fu Hualong; Chen Hao; Dong Bin; Qing Renwei

    2001-01-01

    The authors studied the effects of several heavy metal ions in different concentrations (Cd 2+ , Hg 2+ , Pb 2+ , Cr 6+ ) on the chlorophyll content and cell membrane permeability of Chara vulgaris L. It was discovered that the effects of heavy metal ions on the chlorophyll content and cell membrane permeability of Chara vulgaris L. changed with their different concentration. The trend was that the chlorophyll content and cell membrane permeability were decreased with the increase of the heavy metal ions. The degree of chlorophyll content affected was Cr 6+ , Cd 2+ , Hg 2+ , Pb 2+ , and that of cell membrane permeability affected was Cd 2+ , Cr 6+ , Hg 2+ , Pb 2+

  11. Instability of chlorophyll in yellow lupin seedlings grown in soil contaminated with ciprofloxacin and tetracycline.

    Rydzyński, Dariusz; Piotrowicz-Cieślak, Agnieszka I; Grajek, Hanna; Michalczyk, Dariusz J

    2017-10-01

    With increasing soil concentrations of ciprofloxacin and tetracycline a decrease of leaf chlorophyll content was observed. Tetracycline was more detrimental than ciprofloxacin. The chlorophyll content in plants growing for ten days on a tetracycline containing soil decreased by 68%. The decrease of chlorophyll concentration was even sharper in new leaves that formed after application of the antibiotic (up to 81% drop). The comparison of absorption spectra of commercial, reagent grade chlorophyll, alone and incubated with antibiotics, has shown that ciprofloxacin and tetracycline can react directly with chlorophyll and decrease its concentration by 47.7% and 48.5%, respectively. The changes in fluorescence spectra confirmed the formation of chlorophyll degradation product. The chlorophyll decay was a second order reaction and depended on antibiotic concentration and duration of exposure. Reaction rate constants differed with antibiotics and their soil concentrations. With increasing contents of antibiotics in soil the constant of chlorophyll degradation rate in lupin plants increased from k = 870 M -1 day -1 for 3 mg ciprofloxacin to k = 2490 M -1 day -1 for 90 mg ciprofloxacin, and in the case of tetracycline the reaction rate constant increased from k = 1330 M -1 day -1 to k = 2910 M -1 day -1 . The sensitivity of chlorophyll to ciprofloxacin and tetracycline was confirmed by determining EC and TU indices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Efficiency of portable chlorophyll meters in assessing the nutritional status of wheat plants

    Alessana F. Schlichting

    2015-12-01

    Full Text Available ABSTRACT The objective of this study was to verify the efficiency of two portable chlorophyll meters (Minolta SPAD® 502 and Falker ClorofiLOG® 1030 in assessing the nutritional status of wheat plants, correlating the indices from the devices and the direct determination of chlorophyll content with the concentration of nitrogen (N in the plant. The experiment was conducted in a greenhouse, in pots with 5 dm3 of Oxisol, in a completely randomized design, with six N doses (0, 80, 160, 240, 320 and 400 mg dm-3 and five replicates. At 47 days after emergence, the readings of SPAD and Falker indices and the quantification of chlorophyll content and N concentration in wheat plants were performed, as well as analysis of variance and correlation test, both at 0.05 probability level. The chlorophyll meters Minolta SPAD® 502 and Falker ClorofiLOG® 1030 do not differ with respect to the indirect determination of chlorophyll in wheat plants. The Falker chlorophyll index was statistically equal to the chlorophyll content. Indirect chlorophyll indices and chlorophyll content showed a high correlation with the N concentration in the plant.

  13. Mutants of GABA transaminase (POP2 suppress the severe phenotype of succinic semialdehyde dehydrogenase (ssadh mutants in Arabidopsis.

    Frank Ludewig

    Full Text Available BACKGROUND: The gamma-aminubutyrate (GABA shunt bypasses two steps of the tricarboxylic acid cycle, and is present in both prokaryotes and eukaryotes. In plants, the pathway is composed of the calcium/calmodulin-regulated cytosolic enzyme glutamate decarboxylase (GAD, the mitochondrial enzymes GABA transaminase (GABA-T; POP2 and succinic semialdehyde dehydrogenase (SSADH. We have previously shown that compromising the function of the GABA-shunt, by disrupting the SSADH gene of Arabidopsis, causes enhanced accumulation of reactive oxygen intermediates (ROIs and cell death in response to light and heat stress. However, to date, genetic investigations of the relationships between enzymes of the GABA shunt have not been reported. PRINCIPAL FINDINGS: To elucidate the role of succinic semialdehyde (SSA, gamma-hydroxybutyrate (GHB and GABA in the accumulation of ROIs, we combined two genetic approaches to suppress the severe phenotype of ssadh mutants. Analysis of double pop2 ssadh mutants revealed that pop2 is epistatic to ssadh. Moreover, we isolated EMS-generated mutants suppressing the phenotype of ssadh revealing two new pop2 alleles. By measuring thermoluminescence at high temperature, the peroxide contents of ssadh and pop2 mutants were evaluated, showing that only ssadh plants accumulate peroxides. In addition, pop2 ssadh seedlings are more sensitive to exogenous SSA or GHB relative to wild type, because GHB and/or SSA accumulate in these plants. SIGNIFICANCE: We conclude that the lack of supply of succinate and NADH to the TCA cycle is not responsible for the oxidative stress and growth retardations of ssadh mutants. Rather, we suggest that the accumulation of SSA, GHB, or both, produced downstream of the GABA-T transamination step, is toxic to the plants, resulting in high ROI levels and impaired development.

  14. Distribution of phytoplankton groups within the deep chlorophyll maximum

    Latasa, Mikel

    2016-11-01

    The fine vertical distribution of phytoplankton groups within the deep chlorophyll maximum (DCM) was studied in the NE Atlantic during summer stratification. A simple but unconventional sampling strategy allowed examining the vertical structure with ca. 2 m resolution. The distribution of Prochlorococcus, Synechococcus, chlorophytes, pelagophytes, small prymnesiophytes, coccolithophores, diatoms, and dinoflagellates was investigated with a combination of pigment-markers, flow cytometry and optical and FISH microscopy. All groups presented minimum abundances at the surface and a maximum in the DCM layer. The cell distribution was not vertically symmetrical around the DCM peak and cells tended to accumulate in the upper part of the DCM layer. The more symmetrical distribution of chlorophyll than cells around the DCM peak was due to the increase of pigment per cell with depth. We found a vertical alignment of phytoplankton groups within the DCM layer indicating preferences for different ecological niches in a layer with strong gradients of light and nutrients. Prochlorococcus occupied the shallowest and diatoms the deepest layers. Dinoflagellates, Synechococcus and small prymnesiophytes preferred shallow DCM layers, and coccolithophores, chlorophytes and pelagophytes showed a preference for deep layers. Cell size within groups changed with depth in a pattern related to their mean size: the cell volume of the smallest group increased the most with depth while the cell volume of the largest group decreased the most. The vertical alignment of phytoplankton groups confirms that the DCM is not a homogeneous entity and indicates groups’ preferences for different ecological niches within this layer.

  15. Studies on reduced height mutants in rice

    Narahari, P.; Bhagwat, S.G.

    1984-01-01

    Two cross-bred derivatives of the mutant TR5xTR17 and TR21 continued to show promise and were advanced to wider scale testing. TR5 was found to carry a semi-dwarfing gene different from that in IR8. New semi-dwarf mutants were screened from M 2 through M 4 from two separate radiation experiments. The gibberellin response of seedlings of mutant and tester strains was evaluated and crosses of tester stocks and mutant semi-dwarfs were made for genetic analyses. (author)

  16. Effect of Elevated Atmospheric CO2 and Temperature on Leaf Optical Properties and Chlorophyll Content in Acer saccharum (Marsh.)

    Carter, Gregory A.; Bahadur, Raj; Norby, Richard J.

    1999-01-01

    Elevated atmospheric CO2 pressure and numerous causes of plant stress often result in decreased leaf chlorophyll contents and thus would be expected to alter leaf optical properties. Hypotheses that elevated carbon dioxide pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum Marsh.) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers at Oak Ridge, Tennessee under the following treatments: 1) Ambient CO2 pressure and air temperature (control); 2) CO2 pressure approximately 30 Pa above ambient; 3) Air temperatures 3 C above ambient; 4) Elevated CO2 and air temperature. Spectral reflectance, transmittance, and absorptance in the visible spectrum (400-720 nm) did not change significantly (rho = 0.05) in response to any treatment compared with control values. Although reflectance, transmittance, and absorptance at 700 nm correlated strongly with leaf chlorophyll content, chlorophyll content was not altered significantly by the treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance in leaves that developed under elevated air temperature alone. This response could not be explained by the data, but might have resulted from effects of air temperature on leaf internal structure. Results indicated no significant potential for detecting leaf optical responses to elevated CO2 or temperature by the remote sensing of reflected radiation in the 400-850 nm spectrum.

  17. Genetic fingerprinting of mutant rose cultivars

    Kumar, S; Prasad, K V; Singh, K P; Singh, A.P. [Division of Floriculture and Landscaping, Indian Agricultural Research Institute, Pusa, New Delhi (India)], E-mail: kvprasad66@gmail.com

    2008-07-01

    Six rose mutants evolved at the Indian Agricultural Research Institute, New Delhi from four parent cultivars were characterized based on RAPD markers. Contrary to the earlier findings our effort has conclusively proven that the RAPD markers are indeed robust tools to discern the mutants from their parents. Among 40 primers screened, 7 primers produced inconsistent banding pattern. The number of polymorphic bands varied between 4 (OPA 14) and 10 (OPA1) with an average of 6.5 bands per primer. The percentage polymorphism ranged from 62.5 (OPM 9) to 100 percent (OPA 1). Most of the primers produced monomorphic bands between parent and mutant rose cultivars. When primer OPA 2 was used a specific band of 2.5 kb was noticed in mutant cv. Pusa Urmil and cv. Pusa Abhishek but was absent in parent cv. Jantar Mantar. A polymorphic band of 750 bp was noticed in the parent Kiss of Fire and helped in differentiating the parent from its mutant when amplified with OPK 3. Primer OPS 16 produced discriminatory band of 800 bp in mutant cv. Pink Sport of Montezuma while it was absent in its parent cv. Montezuma. Another specific band of 650 bp was present in parent cv. Montezuma and absent in its mutant cv. Pink Sport of Montezuma signifying the uniqueness of the mutant. Primer OPM 5 brought out distinct polymorphism among the parent Jantar Mantar and its three mutants with absence of a specific band of 1.5 kb in the parent. The four parents and 6 mutants were divided into four distinct groups in the Dendogram constructed by UPGMA method. The most genetically similar cultivar among the 10 cultivars analyzed are Montezuma and its pink sport of Montezuma whereas Abhisarika a mutant of cv. Kiss of Fire was distinctly different and formed a separate cluster. (author)

  18. ENU mutagenesis reveals a novel phenotype of reduced limb strength in mice lacking fibrillin 2.

    Gaynor Miller

    2010-02-01

    Full Text Available Fibrillins 1 (FBN1 and 2 (FBN2 are components of microfibrils, microfilaments that are present in many connective tissues, either alone or in association with elastin. Marfan's syndrome and congenital contractural arachnodactyly (CCA result from dominant mutations in the genes FBN1 and FBN2 respectively. Patients with both conditions often present with specific muscle atrophy or weakness, yet this has not been reported in the mouse models. In the case of Fbn1, this is due to perinatal lethality of the homozygous null mice making measurements of strength difficult. In the case of Fbn2, four different mutant alleles have been described in the mouse and in all cases syndactyly was reported as the defining phenotypic feature of homozygotes.As part of a large-scale N-ethyl-N-nitrosourea (ENU mutagenesis screen, we identified a mouse mutant, Mariusz, which exhibited muscle weakness along with hindlimb syndactyly. We identified an amber nonsense mutation in Fbn2 in this mouse mutant. Examination of a previously characterised Fbn2-null mutant, Fbn2(fp, identified a similar muscle weakness phenotype. The two Fbn2 mutant alleles complement each other confirming that the weakness is the result of a lack of Fbn2 activity. Skeletal muscle from mutants proved to be abnormal with higher than average numbers of fibres with centrally placed nuclei, an indicator that there are some regenerating muscle fibres. Physiological tests indicated that the mutant muscle produces significantly less maximal force, possibly as a result of the muscles being relatively smaller in Mariusz mice.These findings indicate that Fbn2 is involved in integrity of structures required for strength in limb movement. As human patients with mutations in the fibrillin genes FBN1 and FBN2 often present with muscle weakness and atrophy as a symptom, Fbn2-null mice will be a useful model for examining this aspect of the disease process further.

  19. Temperature-sensitive host range mutants of herpes simplex virus type 2

    Koment, R.W.; Rapp, F.

    1975-01-01

    Herpesviruses are capable of several types of infection of a host cell. To investigate the early events which ultimately determine the nature of the virus-host cell interaction, a system was established utilizing temperature-sensitive mutants of herpes simplex virus type 2. Four mutants have been isolated which fail to induce cytopathic effects and do not replicate at 39 C in hamster embryo fibroblast cells. At least one mutant is virus DNA negative. Since intracellular complementation is detectable between pairs of mutants, a virus function is known to be temperature sensitive. However, all four mutants induce cytopathic effects and replicate to parental virus levels in rabbit kidney cells at 39 C. This suggests that a host cell function, lacking or nonfunctional in HEF cells but present in rabbit kidney cells at 39 C, is required for the replication of these mutants in hamster embryo fibroblast cells at 39 C. Therefore, we conclude that these mutants are both temperature sensitive and exhibit host range properties

  20. Trehalose, glycogen and ethanol metabolism in the gcr1 mutant of Saccharomyces cerevisiae

    Seker, Tamay; Hamamci, H.

    2003-01-01

    Since Gcr1p is pivotal in controlling the transcription of glycolytic enzymes and trehalose metabolism seems to be one of the control points of glycolysis, we examined trehalose and glycogen synthesis in response to 2 % glucose pulse during batch growth in gcr1 (glucose regulation-1) mutant lacking...... fully functional glycolytic pathway and in the wild-type strain. An increase in both trehalose and glycogen stores was observed 1 and 2 h after the pulse followed by a steady decrease in both the wild-type and the gcr1 mutant. The accumulation was faster while the following degradation was slower in gcr......1 cells compared to wild-type ones. Although there was no distinct glucose consumption in the mutant cells it seemed that the glucose repression mechanism is similar in gcr1 mutant and in wild-type strain at least with respect to trehalose and glycogen metabolism....

  1. Accumulation of infectious mutants in stocks during the propagation of fiber-modified recombinant adenoviruses

    Ugai, Hideyo; Inabe, Kumiko; Yamasaki, Takahito; Murata, Takehide; Obata, Yuichi; Hamada, Hirofumi; Yokoyama, Kazunari K.

    2005-01-01

    In infected cells, replication errors during viral proliferation generate mutations in adenoviruses (Ads), and the mutant Ads proliferate and evolve in the intracellular environment. Genetically fiber-modified recombinant Ads (rAd variants) were generated, by modification of the fiber gene, for therapeutic applications in host cells that lack or express reduced levels of the Coxsackievirus and adenovirus receptor. To assess the genetic modifications of rAd variants that might induce the instability of Ad virions, we examined the frequencies of mutants that accumulated in propagated stocks. Seven of 41 lines of Ad variants generated mutants in the stocks and all mutants were infectious. Moreover, all the mutations occurred in the modified region that had been added at the 3' end of the fiber gene. Our results show that some genetic modifications at the carboxyl terminus of Ad fiber protein lead to the instability of Ad virions

  2. Radiation-sensitive mutant of hypertoxinogenic strain 569B of Vibro cholerae

    Das, G.; Das, J.

    1983-01-01

    A radiation-sensitive mutant of the hypertoxinogenic strain 569B of Vibrio cholerae was isolated and characterized. The mutant, designated V. cholerae 569Bsub(s), lacks both excision- and medium-dependent dark-repair mechanisms of UV-induced DNA damage while retaining the wild-type photoreactivating capability. Analysis of the UV-irradiated cell DNA by velocity sedimentation in alkaline sucrose gradient suggests that UV-induced pyrimidine dimers may not be incised in these cells. In contrast to the wild-type cells, the mutant cell DNA was degraded after treatment with nalidixic acid. The mutant cells failed to produce any detectable amount of cholera toxin as measured by ileal-loop assay. (orig.)

  3. Resonance Raman spectroscopy of xanthophylls in pigment mutant thylakoid membranes of pea.

    Andreeva, Atanaska; Stoitchkova, Katerina; Busheva, Mira; Apostolova, Emilia; Várkonyi, Zsuzsanna; Garab, Gyözö

    Low-temperature resonance Raman spectroscopy was used to study the changes in the molecular structure and configuration of the major xanthophylls in thylakoid membranes isolated from mutants of pea with modified pigment content and altered structural organization of their pigment-protein complexes. The Raman spectra contained four known groups of bands, nu(1)-nu(4), which could be assigned to originate mainly from the long wavelength absorbing lutein and neoxanthin upon 514.5 nm and at 488 nm excitations, respectively. The overall configuration of these bound xanthophyll molecules in the mutants appeared to be similar to the wild type, and the configuration in the wild type was almost identical with that in the isolated main chlorophyll a/b light harvesting protein complex of photosystem II (LHCII). Significant differences were found mainly in the region of nu(4) (around 960 cm(-1)), which suggest that the macroorganization of PS II-LHCII supercomplexes and/or of the LHCII-only domains are modified in the mutants compared to the wild type. Copyright 2004 Wiley Periodicals, Inc. Biopolymers, 2004

  4. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    Campbell, P.K. Entcheva; Middleton, E.M.; Corp, L.A.; Kim, M.S.

    2008-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance data, which provide estimates of vigor based primarily on chlorophyll content. Chlorophyll fluorescence (ChlF) measurements offer a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, technology based on ChlF may allow more accurate carbon sequestration estimates and earlier stress detection than is possible when using reflectance data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contributions from both the reflected and fluoresced radiation. The aim of this study is to determine the relative contributions of reflectance and ChlF fractions to Ra in the red to near-infrared region (650-800 nm) of the spectrum. The practical objectives of the study are to: 1) evaluate the relationship between ChlF and reflectance at the foliar level for corn, soybean and maple; and 2) for corn, determine if the relationship established for healthy vegetation changes under nitrogen (N) deficiency. To obtain generally applicable results, experimental measurements were conducted on unrelated crop and tree species (corn, soybean and maple) under controlled conditions and a gradient of inorganic N fertilization levels. Optical reflectance spectra and actively induced ChlF emissions were collected on the same foliar samples, in conjunction with measurements of photosynthetic function, pigment levels, and carbon (C) and N content. The spectral trends were examined for similarities. On average, 10-20% of Ra at 685 nm was actually due to ChlF. The spectral trends in steady state and maximum fluorescence varied significantly, with steady state fluorescence (especially red, 685 nm) showing higher ability for species and treatment separation. The relative contribution of ChlF to Ra varied significantly among species, with maple

  5. Microenvironmental Ecology of the Chlorophyll b-containing Symbiotic Cyanobacterium Prochloron in the Didemnid Ascidian Lissoclinum patella

    Michael eKühl

    2012-11-01

    Full Text Available The discovery of the cyanobacterium Prochloron was the first finding of a bacterial oxyphototroph with chlorophyll (Chl b, in addition to Chl a. It was first described as Prochloron didemni but a number of clades have since been described. Prochloron is a conspicuously large (7-25 µm unicellular cyanobacterium living in a symbiotic relationship, primarily with (sub- tropical didemnid ascidians; it has resisted numerous cultivation attempts and appears truly obligatory symbiotic. Recently, a Prochloron draft genome was published, revealing no lack of metabolic genes that could explain the apparent inability to reproduce and sustain photosynthesis in a free-living stage. Possibly, the unsuccessful cultivation is partly due to a lack of knowledge about the microenvironmental conditions and ecophysiology of Prochloron in its natural habitat. We used microsensors, variable chlorophyll fluorescence imaging and imaging of O2 and pH to obtain a detailed insight to the microenvironmental ecology and photobiology of Prochloron in hospite in the didemnid ascidian Lissoclinum patella. The microenvironment within ascidians is characterized by steep gradients of light and chemical parameters that change rapidly with varying irradiances. The interior zone of the ascidians harboring Prochloron thus became anoxic and acidic within a few min of darkness, while the same zone exhibited O2 super-saturation and strongly alkaline pH after a few min of illumination. Photosynthesis showed lack of photoinhibition even at high irradiances equivalent to full sunlight, and photosynthesis recovered rapidly after periods of anoxia. We discuss these new insights on the ecological niche of Prochloron and possible interactions with its host and other microbes in light of its recently published genome and a recent study of the overall microbial diversity and metagenome of L. patella.

  6. Reduced starch granule number per chloroplast in the dpe2/phs1 mutant is dependent on initiation of starch degradation.

    Malinova, Irina; Fettke, Joerg

    2017-01-01

    An Arabidopsis double knock-out mutant lacking cytosolic disproportionating enzyme 2 (DPE2) and the plastidial phosphorylase (PHS1) revealed a dwarf-growth phenotype, reduced starch content, an uneven distribution of starch within the plant rosette, and a reduced number of starch granules per chloroplast under standard growth conditions. In contrast, the wild type contained 5-7 starch granules per chloroplast. Mature and old leaves of the double mutant were essentially starch free and showed plastidial disintegration. Several analyses revealed that the number of starch granules per chloroplast was affected by the dark phase. So far, it was unclear if it was the dark phase per se or starch degradation in the dark that was connected to the observed decrease in the number of starch granules per chloroplast. Therefore, in the background of the double mutant dpe2/phs1, a triple mutant was generated lacking the initial starch degrading enzyme glucan, water dikinase (GWD). The triple mutant showed improved plant growth, a starch-excess phenotype, and a homogeneous starch distribution. Furthermore, the number of starch granules per chloroplast was increased and was similar to wild type. However, starch granule morphology was only slightly affected by the lack of GWD as in the triple mutant and, like in dpe2/phs1, more spherical starch granules were observed. The characterized triple mutant was discussed in the context of the generation of starch granules and the formation of starch granule morphology.

  7. Presence of a chlorophyll d-like pigment in Chlorella extracts

    Michel-Wolwertz, M.R.; Sironval, C.; Goedheer, J.C.

    1965-01-01

    Three chlorophyll a isomers (a₁, a₂ and a₃) were separated by the chromatography of Chlorella extracts on paper 1. One of these, chlorophyll (a₃) showed additional absorption bands at 688 and 455 mμ in diethyl ether. Chromatographic analysis could not decide whether these bands were due to a₃ or

  8. LAI and chlorophyll estimation for a heterogeneous grassland using hyperspectral measurements

    Darvishzadeh, R.; Skidmore, A.K.; Schlerf, M.; Atzberger, C.; Corsi, F.; Cho, M.A.

    2008-01-01

    The study shows that leaf area index (LAI), leaf chlorophyll content (LCC) and canopy chlorophyll content (CCC) can be mapped in a heterogeneous Mediterranean grassland from canopy spectral reflectance measurements. Canopy spectral measurements were made in the field using a GER 3700

  9. Influence of sulphur dioxide on chlorophyll content and catalase activity in some chosen lichen species

    Kuziel, S

    1974-01-01

    The influence of SO/sub 2/ on changes in catalase activity and in chlorophyll content were investigated under laboratory conditions in several lichen species and in maize. In all the plants examined the chlorophyll content and catalase activity decreased after treatment with SO/sub 2/ as compared with that in the control plants.

  10. Low light intensity and nitrogen starvation modulate the chlorophyll content of Scenedesmus dimorphus.

    Ferreira, V S; Pinto, R F; Sant'Anna, C

    2016-03-01

    Chlorophyll is a photosynthetic pigment found in plants and algal organisms and is a bioproduct with human health benefits and a great potential for use in the food industry. The chlorophyll content in microalgae strains varies in response to environmental factors. In this work, we assessed the effect of nitrogen depletion and low light intensity on the chlorophyll content of the Scenedesmus dimorphus microalga. The growth of S. dimorphus under low light intensity led to a reduction in cell growth and volume as well as increased cellular chlorophyll content. Nitrogen starvation led to a reduction in cell growth and the chlorophyll content, changes in the yield and productivity of chlorophylls a and b. Transmission electron microscopy was used to investigate the ultrastructural changes in the S. dimorphus exposed to nitrogen and light deficiency. In contrast to nitrogen depletion, low light availability was an effective mean for increasing the total chlorophyll content of green microalga S. dimorphus. The findings acquired in this work are of great biotechnological importance to extend knowledge of choosing the right culture condition to stimulate the effectiveness of microalgae strains for chlorophyll production purposes. © 2015 The Society for Applied Microbiology.

  11. Genetic and Hormonal Regulation of Chlorophyll Degradation during Maturation of Seeds with Green Embryos.

    Smolikova, Galina; Dolgikh, Elena; Vikhnina, Maria; Frolov, Andrej; Medvedev, Sergei

    2017-09-16

    The embryos of some angiosperms (usually referred to as chloroembryos) contain chlorophylls during the whole period of embryogenesis. Developing embryos have photochemically active chloroplasts and are able to produce assimilates, further converted in reserve biopolymers, whereas at the late steps of embryogenesis, seeds undergo dehydration, degradation of chlorophylls, transformation of chloroplast in storage plastids, and enter the dormancy period. However, in some seeds, the process of chlorophyll degradation remains incomplete. These residual chlorophylls compromise the quality of seed material in terms of viability, nutritional value, and shelf life, and represent a serious challenge for breeders and farmers. The mechanisms of chlorophyll degradation during seed maturation are still not completely understood, and only during the recent decades the main pathways and corresponding enzymes could be characterized. Among the identified players, the enzymes of pheophorbide a oxygenase pathway and the proteins encoded by STAY GREEN ( SGR ) genes are the principle ones. On the biochemical level, abscisic acid (ABA) is the main regulator of seed chlorophyll degradation, mediating activity of corresponding catabolic enzymes on the transcriptional level. In general, a deep insight in the mechanisms of chlorophyll degradation is required to develop the approaches for production of chlorophyll-free high quality seeds.

  12. Study of 660 nm laser-induced photoluminescence of chlorophyll-a and its applications

    Song, Y; Zhang, D X; Zhang, H J

    2007-01-01

    Based on the phenomenon of chlorophyll a photoluminescence, this paper introduces a new method to measure the chlorophyll a content, using 660nm laser diode as a new kind of light source to stimulate fluorescence as well as combining a fiber and spectrum technique. We analyze the characteristics of laser-induced fluorescence spectrum of chlorophyll a and then put forward the new method using two parameters, the relative fluorescence intensity and fluorescence intensity ratio F685/F735, to measure the chlorophyll a content in the water and green leaves respectively. The experimental results indicate that it is completely feasible to give a visual judgment for chlorophyll a content, according to the fluorescence emission spectrum of chlorophyll a. Subsequently, it is verified by three kinds of typical applications. All of these provide a new kind of light source to develop the chlorophyll a fluorometry and further give a technical foundation of on-spot monitoring the chlorophyll a content in the ocean or in green leaves

  13. Nondestructive and intuitive determination of circadian chlorophyll rhythms in soybean leaves using multispectral imaging

    Pan, Wen-Juan; Wang, Xia; Deng, Yong-Ren; Li, Jia-Hang; Chen, Wei; Chiang, John Y.; Yang, Jian-Bo; Zheng, Lei

    2015-01-01

    The circadian clock, synchronized by daily cyclic environmental cues, regulates diverse aspects of plant growth and development and increases plant fitness. Even though much is known regarding the molecular mechanism of circadian clock, it remains challenging to quantify the temporal variation of major photosynthesis products as well as their metabolic output in higher plants in a real-time, nondestructive and intuitive manner. In order to reveal the spatial-temporal scenarios of photosynthesis and yield formation regulated by circadian clock, multispectral imaging technique has been employed for nondestructive determination of circadian chlorophyll rhythms in soybean leaves. By utilizing partial least square regression analysis, the determination coefficients R2, 0.9483 for chlorophyll a and 0.8906 for chlorophyll b, were reached, respectively. The predicted chlorophyll contents extracted from multispectral data showed an approximately 24-h rhythm which could be entrained by external light conditions, consistent with the chlorophyll contents measured by chemical analyses. Visualization of chlorophyll map in each pixel offers an effective way to analyse spatial-temporal distribution of chlorophyll. Our results revealed the potentiality of multispectral imaging as a feasible nondestructive universal assay for examining clock function and robustness, as well as monitoring chlorophyll a and b and other biochemical components in plants. PMID:26059057

  14. Using hyperspectral remote sensing data for retrieving canopy chlorophyll and nitrogen content

    Clevers, J.G.P.W.; Kooistra, L.

    2012-01-01

    Plant stress is often expressed as a reduction in amount of biomass or leaf area index (LAI). In addition, stress may affect the plant pigment system, influencing the photosynthetic capacity of plants. Chlorophyll content is the main driver for this primary production. The chlorophyll content is

  15. TOXICITY OF INDUSTRIAL EFFLUENT ON TOTAL CHLOROPHYLL CONTENT OF CERTAIN AQUATIC MACROPHYTES

    Singh Priti; Vishen Ashish; Wadhwani R; Pandey Y.N

    2012-01-01

    To assess the toxicity of industrial effluents on certain macrophytes, the total chlorophyll content of free floating, submerged and emergent macrophytes were estimated in concentrations of industrial effluents at varying exposure duration. The result revealed reduction in total chlorophyll content of exposed macrophytes at higher concentrations of industrial effluents on prolonged duration.

  16. Substratum as a driver of variation in periphyton chlorophyll and productivity in lakes

    Vadeboncoeur, Y.; Kalff, J.; Christoffersen, Kirsten Seestern

    2006-01-01

    content of periphyton on hard substrata (rocks and wood) was positively related to water-column total P (TP), whereas chlorophyll content of algae on sediment (epipelon) and TP were not significantly related. Chlorophyll content was up to 100× higher on sediments than on hard substrata. Within regions...... of the littoral zones in nutrient and energy cycles in lakes....

  17. Thermocline Regulated Seasonal Evolution of Surface Chlorophyll in the Gulf of Aden

    Yao, Fengchao; Hoteit, Ibrahim

    2015-01-01

    , the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) ocean color data reveal that the Gulf of Aden also exhibits a prominent summer chlorophyll bloom and sustains elevated chlorophyll concentrations throughout the fall, and is a biophysical province

  18. Genetic and Hormonal Regulation of Chlorophyll Degradation during Maturation of Seeds with Green Embryos

    Galina Smolikova

    2017-09-01

    Full Text Available The embryos of some angiosperms (usually referred to as chloroembryos contain chlorophylls during the whole period of embryogenesis. Developing embryos have photochemically active chloroplasts and are able to produce assimilates, further converted in reserve biopolymers, whereas at the late steps of embryogenesis, seeds undergo dehydration, degradation of chlorophylls, transformation of chloroplast in storage plastids, and enter the dormancy period. However, in some seeds, the process of chlorophyll degradation remains incomplete. These residual chlorophylls compromise the quality of seed material in terms of viability, nutritional value, and shelf life, and represent a serious challenge for breeders and farmers. The mechanisms of chlorophyll degradation during seed maturation are still not completely understood, and only during the recent decades the main pathways and corresponding enzymes could be characterized. Among the identified players, the enzymes of pheophorbide a oxygenase pathway and the proteins encoded by STAY GREEN (SGR genes are the principle ones. On the biochemical level, abscisic acid (ABA is the main regulator of seed chlorophyll degradation, mediating activity of corresponding catabolic enzymes on the transcriptional level. In general, a deep insight in the mechanisms of chlorophyll degradation is required to develop the approaches for production of chlorophyll-free high quality seeds.

  19. The effect of shade on chlorophyll and anthocyanin content of upland red rice

    Muhidin; Syam'un, E.; Kaimuddin; Musa, Y.; Sadimantara, G. R.; Usman; Leomo, S.; Rakian, T. C.

    2018-02-01

    Upland red rice (Oryza sativa) is a staple food and contains anthocyanin, which can act as antioxidants, plays an important role both for the plant itself and for human health. Levels of antioxidants in rice can be affected by the availability of light. The results showed that the difference of shade, cultivar, and interaction both significantly affect the content of chlorophyll a, chlorophyll b and total chlorophyll. The results also showed that shade could increase chlorophyll in all cultivars tested. The highest levels of chlorophyll a were present in the moderate shade level (n2), then decreased at the shelter level (n3) and increased again at high levels (n4). While on chlorophyll content b, it appears that shade increased chlorophyll b in all cultivars tested and this increase was linear to the increase of shade. The shade treatment may increase the anthocyanin content and the increase depending on the type of cultivar. Increased levels of anthocyanin highest due to shade occurred on Jangkobembe cultivar. The original level of anthocyanin on Jangkobembe cultivar averaged 0.096 mg g-1 increased to 2.487 mg g-1 or increased 26 fold. It is concluded that the shade had a significant effect on the chlorophyll and anthocyanin content.

  20. A mutant of a mutant of a mutant of a ...: Irradiation of progressive radiation-induced mutants in a mutation-breeding programme with Chrysanthenum morifolium RAM

    Broertjes, C.; Koene, P.; Veen, J.W.H. van.

    1980-01-01

    Radiation-induced sports in Chrysanthemum morifolium RAM. have been reported for several years. It has become an everyday practice to produce flower-colour mutants from outstanding cross-breeding products, even before they are distributed for the commercial production of cut flowers. One of the most successful and recent examples is that of cv. Horim, of which hundreds of mutants were produced by successive use of radiation-induced mutants in the mutation-breeding programme. Over about 4 years a variety of flower-colour mutants was obtained, not only largely including the outstanding characteristics of the original cultivar but sometimes even with an appreciable improvement in quality and yield. It is expected that the latter types, the Miros group, will soon completely supersede the spontaneous or raditation-induced Horim sports and mutants and take over the leading position of the Horim group in the production of all-year-round (AYR) cut-flowers. (orig.)

  1. Chlorophyll meter for estimating nitrogen status of irrigated wheat

    Schepers, J.S.

    2000-01-01

    Chlorophyll-meter readings, generated from the leaves of irrigated wheat at particular growth stages, were normalized to the data obtained with locally recommended rates of fertilizer N, in Chile China, India and Mexico. Normalizing permitted comparisons of crop-N status across growth stages, locations, cultivars, and years. Relative yields and meter readings at growth-stage Z-50 are presented; they revealed similar trends for India, China, and Chile, however, for Mexico, the combination of soil, wheat cultivar, and climate resulted in much less response to N fertilization in the meter data. The implications are discussed. The SPAD meter proved to be a good tool to monitor and evaluate the N status of irrigated wheat. (author)

  2. Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

    Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

    2016-03-01

    Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

  3. Canopy Level Chlorophyll Fluorescence and the PRI in a Cornfield

    Middleton, Elizabeth M.; Cheng, Yen-Ben; Corp, Lawrence A.; Campbell, Petya K. E.; Huemmrich, K. Fred; Zhang, Qingyuan; Kustas, William P.

    2012-01-01

    Two bio-indicators, the Photochemical Reflectance Index (PRI) and solar-induced red and far-red Chlorophyll Fluorescence (SIF), were derived from directional hyperspectral observations and studied in a cornfield on two contrasting days in the growing season. Both red and far-red SIF exhibited higher values on the day when the canopy in the early senescent stage, but only the far-red SIF showed sensitivity to viewing geometry. Consequently, the red/far-red SIF ratio varied greatly among azimuth positions while the largest values were obtained for the "hotspot" at both growth stages. This ratio was lower (approx.0.88 +/- 0.4) in early July than in August when the ratio approached equivalence (near approx.1). In concert, the PRI exhibited stronger responses to both zenith and azimuth angles and different values on the two growth stages. The potential of using these indices to monitor photosynthetic activities needs further investigation

  4. Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

    Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

    2017-11-01

    Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

  5. Chlorophyll a fluorescence to phenotype wheat genotypes for heat tolerance

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    In prospects of global climate change, heat stress is a rising constraint for the productivity of wheat (Triticum aestivum L.). It is a heat-susceptible crop beyond 17-23oC temperature throughout its phenological stages, flowering phase being the most sensitive stage. Chlorophyll a fluorescence...... parameter, maximum quantum yield efficiency of PSII (Fv/Fm) is used as a physiological marker for early stress detection in PSII in plants. We established a reproducible protocol to measure response of wheat genotypes to high temperature based on Fv/Fm. The heat treatment of 40°C in 300 µmol m-2s-1 PAR...... enabled the identification of contrasting wheat genotypes that can be used to study the genetic and physiological nature of heat stress tolerance to dissect quantitative traits into simpler and more heritable traits....

  6. Los mutantes de la escuela

    Diego Armando Jaramillo-Ocampo

    2013-01-01

    Full Text Available El presente artículo muestra los resultados parciales del estudio “Juegos en el recreo escolar: un escenario para la formación ciudadana”, cuya pretensión fue comprender los imaginarios sociales de juego en el recreo escolar y su relación con la convivencia social desde la proximidad del enfoque de complementariedad y el diseño de investigación emergente, planteado por Murcia y Jaramillo (2008. Se presentan los desarrollos logrados en dos categorías centrales del estudio: el patio y el cuerpo; dos categorías que mutan constantemente como entidades vivas en la escuela, hacia la configuración de sujetos que reconocen en el otro y lo otro su posibilidad. La escuela viva, donde es posible “ser en relación con”… se reduce a un espacio temporal y físico, limitado por la campana, “el recreo”. El texto muestra, desde la voz de los actores, esa vida que se da y se quita en la escuela y que se posiciona como una más de las imposiciones normalizadas para controlar. Reconoce, finalmente, una propuesta desde la posibilidad que estos dos mutantes propician para una escuela libre y dinámica.

  7. Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

    Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

    2017-06-01

    Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

  8. The power of pigments, calibrating chemoclines with chlorophylls and carotenoids.

    Junium, C. K.; Uveges, B. T.

    2017-12-01

    Phototrophic organisms produce a diversity of pigments that serve a broad range of specific biochemical functions. Pigments are either directly associated with the photosynthetic apparatus, the most notable being chlorophyll a, or are accessory pigments such as the carotenoid lutein. Their functions can also be categorized into roles that are related to light harvesting (e.g. fucoxanthin) or for photoprotection (e.g. scytonemin). The abundances of these two classes of pigments from environmental samples can provide specific information about photointensity and how it relates to environmental changes. For example, a deepening of the chemo/nutricline can result in the increased production of light gathering relative to photoprotective pigments. Here we apply a relatively simple approach that utilizes the abundance of photosynthetic relative to photoprotective pigments to help constrain changes in the water column position of the chemocline. To test the efficacy of this approach we have utilized the sedimentary record of the anoxic Lake Kivu in the East African Rift. Recent Lake Kivu sediments are punctuated by a series of sapropels that may be associated with overturn of the lake, and release of carbon dioxide and sulfide during potential limnic eruptions. Carbon and nitrogen isotopes decrease significantly at the onset of sapropel deposition and suggest that 13C-depleted dissolved inorganic carbon was upwelled into surface waters and was accompanied by high concentrations of ammonium, that allowed for 15N-depletion during incomplete nitrogen utilization. The pigment record, specifically the ratio of the photoprotective carotenoids lutein and zeaxanthin to chlorophyll a increases significantly at the onset of sapropel deposition. This suggests that the chemocline shallowed, displacing phototrophic communities toward the surface of the lake where light intensities required production of photoprotective pigments. This approach can easily be applied to a wide variety of

  9. Research on the ultrafast fluorescence property of thylakoid membranes of the wild-type and mutant rice

    Ren, Zhao-Yu; Xu, Xiao-Ming; Wang, Shui-Cai; Xin, Yue-Yong; He, Jun-Fang; Hou, Xun

    2003-10-01

    A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wild-type rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wild-type. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

  10. Researches Regarding the Influence of Cold Storage on the Chlorophyll Content in Lettuce

    Iuliana Cretescu

    2014-05-01

    Full Text Available The aim of the present investigations was to determine the effect of the cold storage period on the content of chlorophylls in the leaves of lettuce and arugula (rucola. The research material consisted in two types of lettuce (Lactuca sativa L. var. capitata; Lactuca sativa L. var. crispa and arugula (Eruca sativa purchased from supermarkets in Timisoara. The quantitative determination of chlorophyll pigments in leaves (SPAD was made by chlorophyll meter (SPAD 502 Konica-Minolta. During the few days cold storage at a temperature of 4ºC, the content of chlorophyll in the leaf significantly decreased, compared with that in the control group. After 3 days of cold storage arugula and lettuce (Lactuca sativa var. capitata values of chlorophyll content differ statistically very significantly (p<0.001 from the values found in the control group which for lettuce (Lactuca sativa L. var. crispa differs statistically significant (p < 0.05.

  11. The effect of storage temperature of cucumber fruit on chlorophyll fluorescence

    Ryszard Kosson

    2013-12-01

    Full Text Available The effect of three storage temperature levels: 12,5°C, 20°C, and 1,5°C on basic indexes of chlorophyll fluorescence of cucumber fruits was studied. The greenhouse grown cucumber fruits cv. Wiktor F1 were stored in perforated polyethylene bags or without packages. The minimum chlorophyll fluorescence (Fo, maximum chlorophyll fluorescence (Fm, variable chlorophyll fluorescence (Fv and relative variable fluorescence (Fv/Fm of the cucumber peel were measured. Relative variable fluorescence was decTeasing when cucumbers were stored at temperature lower or higher than optimum level. The chlorophyll fluorescence measurements can be helpful for determination of appropriate temperature parameters of cucumber storage.

  12. Thermocline Regulated Seasonal Evolution of Surface Chlorophyll in the Gulf of Aden

    Hoteit, Ibrahim

    2015-04-01

    The Gulf of Aden, although subject to seasonally reversing monsoonal winds, has been previously reported as an oligotrophic basin during summer, with elevated chlorophyll concentrations only occurring during winter due to convective mixing. However, the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) ocean color data reveal that the Gulf of Aden also exhibits a prominent summer chlorophyll bloom and sustains elevated chlorophyll concentrations throughout the fall, and is a biophysical province distinct from the adjacent Arabian Sea. Climatological hydrographic data suggest that the thermocline, hence the nutricline, in the entire gulf is markedly shoaled by the southwest monsoon during summer and fall. Under this condition, cyclonic eddies in the gulf can effectively pump deep nutrients to the surface layer and lead to the chlorophyll bloom in late summer, and, after the transition to the northeast monsoon in fall, coastal upwelling driven by the northeasterly winds produces a pronounced increase in surface chlorophyll concentrations along the Somali coast.

  13. Stomata character and chlorophyll content of tomato in response to Zn application under drought condition

    Sakya, A. T.; Sulistyaningsih, E.; Indradewa, D.; Purwanto, B. H.

    2018-03-01

    This experiment was performed in order to evaluate the effects of Zn application under drought condition on tomato, especially its chlorophyll content and stomata character. This experiment was arranged in factorial using randomized complete block design with three replications. The treatment consisted of the Zn application method, namely: soil and foliar, the Zn dosage, namely: 0, 40 and 60 mg ZnSO4 kg-1 soil and two cultivars of tomato, namely: ‘Tyrana’ F1 and ‘Permata’ F1. The stress condition was induced by watering every 12 days of 3 weeks after transplanting until harvesting. The results showed that the soil with a Zn application under drought conditions increased the aperture stomata, chlorophyll b and chlorophyll a/b ratio. The response of stomata character, chlorophyll a and total chlorophyll in both cultivars was similar.

  14. Hyperspectral imaging detection of decayed honey peaches based on their chlorophyll content.

    Sun, Ye; Wang, Yihang; Xiao, Hui; Gu, Xinzhe; Pan, Leiqing; Tu, Kang

    2017-11-15

    Honey peach is a very common but highly perishable market fruit. When pathogens infect fruit, chlorophyll as one of the important components related to fruit quality, decreased significantly. Here, the feasibility of hyperspectral imaging to determine the chlorophyll content thus distinguishing diseased peaches was investigated. Three optimal wavelengths (617nm, 675nm, and 818nm) were selected according to chlorophyll content via successive projections algorithm. Partial least square regression models were established to determine chlorophyll content. Three band ratios were obtained using these optimal wavelengths, which improved spatial details, but also integrates the information of chemical composition from spectral characteristics. The band ratio values were suitable to classify the diseased peaches with 98.75% accuracy and clearly show the spatial distribution of diseased parts. This study provides a new perspective for the selection of optimal wavelengths of hyperspectral imaging via chlorophyll content, thus enabling the detection of fungal diseases in peaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Chlorophyll Extraction from Microalgae: A Review on the Process Engineering Aspects

    Aris Hosikian

    2010-01-01

    Full Text Available Chlorophyll is an essential compound in many everyday products. It is used not only as an additive in pharmaceutical and cosmetic products but also as a natural food colouring agent. Additionally, it has antioxidant and antimutagenic properties. This review discusses the process engineering of chlorophyll extraction from microalgae. Different chlorophyll extraction methods and chlorophyll purification techniques are evaluated. Our preliminary analysis suggests supercritical fluid extraction to be superior to organic solvent extraction. When compared to spectroscopic technique, high performance liquid chromatography was shown to be more accurate and sensitive for chlorophyll analysis. Finally, through CO2 capture and wastewater treatment, microalgae cultivation process was shown to have strong potential for mitigation of environmental impacts.

  16. Preparation of a chlorophyll derivative and investigation of its photodynamic activities against cholangiocarcinoma.

    Wu, Zhong-Ming; Wang, Li; Zhu, Wei; Gao, Ying-Hua; Wu, Hai-Ming; Wang, Mi; Hu, Tai-Shan; Yan, Yi-Jia; Chen, Zhi-Long

    2017-08-01

    Photodynamic therapy (PDT) is emerging as a promising method for the treatment of various cancer diseases. However, the clinical application of PDT is limited due to the lack of effective photosensitizers. In this study, a novel chlorophyll derivative, N,N-bis(2-carboxyethyl)pyropheophorbide a (BPPA), had been synthesized and characterized. BPPA had a characteristic long wavelength absorption peak at 669nm and a singlet oxygen quantum yield of 0.54. To investigate the photodynamic ability of BPPA against cholangiocarcinoma (CCA), cellular uptake, subcellular location and bio-distribution, in vitro and in vivo PDT efficacy of BPPA were studied. The results showed that BPPA could rapidly accumulate in QBC-939 cells and localize in the cytoplasm. BPPA- PDT was effective in reducing the cell viability in a drug dose- and light dose-dependent manner in vitro. In CCA xenograft nude mouse model, the concentration of BPPA in the plasma lowered rapidly, and the fluorescence signal peaked at 0.5h and 2h after injection in the skin and tumor, respectively. Significant quantities could be observed in the tumor. BPPA followed by irradiation could significantly inhibit growth of tumors, and histological examination revealed necrotic damage in PDT-treated tumors. These results suggested that BPPA could be a promising drug candidate for photodynamic therapy in cholangiocarcinoma. Published by Elsevier Masson SAS.

  17. Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system

    Ellouzi, Hasna; Hamed, Karim Ben; Cela, Jana; Müller, Maren; Abdelly, Chedly; Munné-Bosch, Sergi

    2013-01-01

    Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na+, (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na+/K+ homeostasis and hormonal balance. PMID:23299430

  18. Induction of Mutants in Durum Wheat

    AL-Ubaidi, M.; Ibrahim, I.; AL-Hadithi, A.

    2002-01-01

    This investigation presents a breeding program for induction and development of a new genotype of durum wheat, resistant to lodging with high yield, by irradiation durum wheat hybrids (F2) with gamma rays 100 Gy, during 1990-1997 cultivation seasons. This program involves: induction of variability, selection evaluation of the mutants at three locations: Twaitha (Baghdad) Latifya ( Babylon) and Swari (Kutt). All mutants showed resistance to lodging and there was a significant reduction in plant height. Mutant SIXIZ-22 surpassed other mutants and its origin in lodging resistance and plant height (83.5,82.8 and 89.4 cm) in the three locations at generation M5 and M6, respectively. Also, there were significant differences between mutant and their origin in the number of spikes/M 2 and grain yild during the two successive generation. On the other hand, mutant IZxCO-105 surpassed other mutants in the number of spikes/M 2 (231.8,242.3 and 292) and grain yield (4336,3376 and 5232 kg/ha) in all testing location, respectively . (authors) 14 refs., 4 tabs

  19. ABF2, ABF3, and ABF4 Promote ABA-Mediated Chlorophyll Degradation and Leaf Senescence by Transcriptional Activation of Chlorophyll Catabolic Genes and Senescence-Associated Genes in Arabidopsis.

    Gao, Shan; Gao, Jiong; Zhu, Xiaoyu; Song, Yi; Li, Zhongpeng; Ren, Guodong; Zhou, Xin; Kuai, Benke

    2016-09-06

    Chlorophyll (Chl) degradation is an integral process of leaf senescence, and NYE1/SGR1 has been demonstrated as a key regulator of Chl catabolism in diverse plant species. In this study, using yeast one-hybrid screening, we identified three abscisic acid (ABA)-responsive element (ABRE)-binding transcription factors, ABF2 (AREB1), ABF3, and ABF4 (AREB2), as the putative binding proteins of the NYE1 promoter. Through the transactivation analysis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we demonstrated that ABF2, ABF3, and ABF4 directly bound to and activated the NYE1 promoter in vitro and in vivo. ABA is a positive regulator of leaf senescence, and exogenously applied ABA can accelerate Chl degradation. The triple mutant of the ABFs, abf2abf3abf4, as well as two ABA-insensitive mutants, abi1-1 and snrk2.2/2.3/2.6, exhibited stay-green phenotypes after ABA treatment, along with decreased induction of NYE1 and NYE2 expression. In contrast, overexpression of ABF4 accelerated Chl degradation upon ABA treatment. Interestingly, ABF2/3/4 could also activate the expression of two Chl catabolic enzyme genes, PAO and NYC1, by directly binding to their promoters. In addition, abf2abf3abf4 exhibited a functional stay-green phenotype, and senescence-associated genes (SAGs), such as SAG29 (SWEET15), might be directly regulated by the ABFs. Taken together, our results suggest that ABF2, ABF3, and ABF4 likely act as key regulators in mediating ABA-triggered Chl degradation and leaf senescence in general in Arabidopsis. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

  20. An Arabidopsis thaliana knock-out mutant of the chloroplast triose phosphate/phosphate translocator is severely compromised only when starch synthesis, but not starch mobilisation is abolished

    Schneider, Anja; Häusler, Rainer E; Kolukisaoglu, Uner

    2002-01-01

    The Arabidopsis thaliana tpt-1 mutant which is defective in the chloroplast triose phosphate/phosphate translocator (TPT) was isolated by reverse genetics. It contains a T-DNA insertion 24 bp upstream of the start ATG of the TPT gene. The mutant lacks TPT transcripts and triose phosphate (TP)-spe...

  1. Spectrum of induced floral mutants in Petunia

    Padmaja, V.; Sudhakar, P.

    1987-01-01

    A total of six floral mutants of garden Petunia isolated from the populations raised from the seed treatment with γ-rays, 2, 4-D and sodium azide are described. Five of the mutants viz. stellata, Campyloflora, Rubriflora mixed, Grandiflora and Albiflora mixed originated as segregants in M 2 generation while the chimeral floral phenotype was expressed in M 1 generation itself. Breeding behaviour of these horticulturally interesting altered floral phenotypes were studied in subsequent generations and appropriate conclusions were drawn regarding mode of inheritance of the mutant traits. 15 refs., 4 figures, 1 table. (author)

  2. Chemical transformations of chlorophyll and its application in the design of a new generation of environmentally safe dyes

    Berezin, Boris D; Rumyantseva, Svetlana V; Moryganov, Andrey P; Berezin, Mikhail B [Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo (Russian Federation)

    2004-02-28

    Chemical transformations of chlorophyll and physicochemical properties of its derivatives are considered. These compounds can be used in the design of a new generation of chlorophyll- and porphyrin-based dyes environmentally more safe than currently used arene dyes and possessing renewable sources of raw materials. The first results on the use of chlorophyll derivatives for dyeing wool, acetate fibres and cotton are reported.

  3. Chemical transformations of chlorophyll and its application in the design of a new generation of environmentally safe dyes

    Berezin, Boris D; Rumyantseva, Svetlana V; Moryganov, Andrey P; Berezin, Mikhail B

    2004-01-01

    Chemical transformations of chlorophyll and physicochemical properties of its derivatives are considered. These compounds can be used in the design of a new generation of chlorophyll- and porphyrin-based dyes environmentally more safe than currently used arene dyes and possessing renewable sources of raw materials. The first results on the use of chlorophyll derivatives for dyeing wool, acetate fibres and cotton are reported.

  4. Atmospheric CO2 Observations Reveal Strong Correlation Between Regional Net Biospheric Carbon Uptake and Solar-Induced Chlorophyll Fluorescence

    Shiga, Yoichi P.; Tadić, Jovan M.; Qiu, Xuemei; Yadav, Vineet; Andrews, Arlyn E.; Berry, Joseph A.; Michalak, Anna M.

    2018-01-01

    Recent studies have shown the promise of remotely sensed solar-induced chlorophyll fluorescence (SIF) in informing terrestrial carbon exchange, but analyses have been limited to either plot level ( 1 km2) or hemispheric/global ( 108 km2) scales due to the lack of a direct measure of carbon exchange at intermediate scales. Here we use a network of atmospheric CO2 observations over North America to explore the value of SIF for informing net ecosystem exchange (NEE) at regional scales. We find that SIF explains space-time NEE patterns at regional ( 100 km2) scales better than a variety of other vegetation and climate indicators. We further show that incorporating SIF into an atmospheric inversion leads to a spatial redistribution of NEE estimates over North America, with more uptake attributed to agricultural regions and less to needleleaf forests. Our results highlight the synergy of ground-based and spaceborne carbon cycle observations.

  5. Chlorophyll mutation in field Pea (Pisum Sativum L.) that causes white stem in plants

    Naidenova, N.; Vassilevska-Ivanova, R.

    2006-01-01

    A white stem pea mutant recovered after exposing seeds of P. sativum cv Auralia to gamma-irradiation. The mutant has shown to have single-gene recessive inheritance, characterized morphologically and for seed productivity. New mutant 1/240 had similar phenotype to previously named mutants white stem and alts (albina-terminalis) but no allelism tests were performed between the new and the previously reported mutants. The mutation in line 1/240 may be useful as a genetic marker. (authors)

  6. Completing the Feedback Loop: The Impact of Chlorophyll Data Assimilation on the Ocean State

    Borovikov, Anna; Keppenne, Christian; Kovach, Robin

    2015-01-01

    In anticipation of the integration of a full biochemical model into the next generation GMAO coupled system, an intermediate solution has been implemented to estimate the penetration depth (1Kd_PAR) of ocean radiation based on the chlorophyll concentration. The chlorophyll is modeled as a tracer with sources-sinks coming from the assimilation of MODIS chlorophyll data. Two experiments were conducted with the coupled ocean-atmosphere model. In the first, climatological values of Kpar were used. In the second, retrieved daily chlorophyll concentrations were assimilated and Kd_PAR was derived according to Morel et al (2007). No other data was assimilated to isolate the effects of the time-evolving chlorophyll field. The daily MODIS Kd_PAR product was used to validate the skill of the penetration depth estimation and the MERRA-OCEAN re-analysis was used as a benchmark to study the sensitivity of the upper ocean heat content and vertical temperature distribution to the chlorophyll input. In the experiment with daily chlorophyll data assimilation, the penetration depth was estimated more accurately, especially in the tropics. As a result, the temperature bias of the model was reduced. A notably robust albeit small (2-5 percent) improvement was found across the equatorial Pacific ocean, which is a critical region for seasonal to inter-annual prediction.

  7. Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops.

    Gitelson, Anatoly A; Peng, Yi; Viña, Andrés; Arkebauer, Timothy; Schepers, James S

    2016-08-20

    One of the main factors affecting vegetation productivity is absorbed light, which is largely governed by chlorophyll. In this paper, we introduce the concept of chlorophyll efficiency, representing the amount of gross primary production per unit of canopy chlorophyll content (Chl) and incident PAR. We analyzed chlorophyll efficiency in two contrasting crops (soybean and maize). Given that they have different photosynthetic pathways (C3 vs. C4), leaf structures (dicot vs. monocot) and canopy architectures (a heliotrophic leaf angle distribution vs. a spherical leaf angle distribution), they cover a large spectrum of biophysical conditions. Our results show that chlorophyll efficiency in primary productivity is highly variable and responds to various physiological and phenological conditions, and water availability. Since Chl is accessible through non-destructive, remotely sensed techniques, the use of chlorophyll efficiency for modeling and monitoring plant optimization patterns is practical at different scales (e.g., leaf, canopy) and under widely-varying environmental conditions. Through this analysis, we directly related a functional characteristic, gross primary production with a structural characteristic, canopy chlorophyll content. Understanding the efficiency of the structural characteristic is of great interest as it allows explaining functional components of the plant system. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Differential effects of glyphosate and aminomethylphosphonic acid (AMPA) on photosynthesis and chlorophyll metabolism in willow plants.

    Gomes, Marcelo Pedrosa; Le Manac'h, Sarah Gingras; Maccario, Sophie; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

    2016-06-01

    We used a willow species (Salix miyabeana cultivar SX64) to examine the differential secondary-effects of glyphosate and aminomethylphosphonic acid (AMPA), the principal glyphosate by-product, on chlorophyll metabolism and photosynthesis. Willow plants were treated with different concentrations of glyphosate (equivalent to 0, 1.4, 2.1 and 2.8kgha(-1)) and AMPA (equivalent to 0, 0.28, 1.4 and 2.8kgha(-1)) and evaluations of pigment contents, chlorophyll fluorescence, and oxidative stress markers (hydrogen peroxide content and antioxidant enzyme activities) in leaves were performed after 12h of exposure. We observed that AMPA and glyphosate trigger different mechanisms leading to decreases in chlorophyll content and photosynthesis rates in willow plants. Both chemicals induced ROS accumulation in willow leaves although only glyphosate-induced oxidative damage through lipid peroxidation. By disturbing chlorophyll biosynthesis, AMPA induced decreases in chlorophyll contents, with consequent effects on photosynthesis. With glyphosate, ROS increases were higher than the ROS-sensitive threshold, provoking chlorophyll degradation (as seen by pheophytin accumulation) and invariable decreases in photosynthesis. Peroxide accumulation in both AMPA and glyphosate-treated plants was due to the inhibition of antioxidant enzyme activities. The different effects of glyphosate on chlorophyll contents and photosynthesis as described in the literature may be due to various glyphosate:AMPA ratios in those plants. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Synechocystis sp. PCC 6803 CruA (sll0147) encodes lycopene cyclase and requires bound chlorophyll a for activity.

    Xiong, Wei; Shen, Gaozhong; Bryant, Donald A

    2017-03-01

    The genome of the model cyanobacterium, Synechococcus sp. PCC 7002, encodes two paralogs of CruA-type lycopene cyclases, SynPCC7002_A2153 and SynPCC7002_A0043, which are denoted cruA and cruP, respectively. Unlike the wild-type strain, a cruA deletion mutant is light-sensitive, grows slowly, and accumulates lycopene, γ-carotene, and 1-OH-lycopene; however, this strain still produces β-carotene and other carotenoids derived from it. Expression of cruA from Synechocystis sp. PCC 6803 (cruA 6803 ) in Escherichia coli strains that synthesize either lycopene or γ-carotene did not lead to the synthesis of either γ-carotene or β-carotene, respectively. However, expression of this orthologous cruA 6803 gene (sll0147) in the Synechococcus sp. PCC 7002 cruA deletion mutant produced strains with phenotypic properties identical to the wild type. CruA 6803 was purified from Synechococcus sp. PCC 7002 by affinity chromatography, and the purified protein was pale yellow-green due to the presence of bound chlorophyll (Chl) a and β-carotene. Native polyacrylamide gel electrophoresis of the partly purified protein in the presence of lithium dodecylsulfate at 4 °C confirmed that the protein was yellow-green in color. When purified CruA 6803 was assayed in vitro with either lycopene or γ-carotene as substrate, β-carotene was synthesized. These data establish that CruA 6803 is a lycopene cyclase and that it requires a bound Chl a molecule for activity. Possible binding sites for Chl a and the potential regulatory role of the Chl a in coordination of Chl and carotenoid biosynthesis are discussed.

  10. Semi-dwarf mutants for rice improvement

    Othman, Ramli; Osman, Mohammad; Ibrahim, Rusli

    1990-01-01

    Full text: MARDI and the National University of Malaysia embarked on a programme to induce resistance against blast in rice in 1978. MARDI also obtained semi dwarf mutants of cvs 'Mahsuri', 'Muda', 'Pongsu seribu' and 'Jarum Mas', which are under evaluation. The popular local rice variety 'Manik' was subjected to gamma irradiation (15-40 krad) and 101 promising semidwarf mutants have been obtained following selection in M 2 -M 6 . 29 of them show grain yields of 6.0-7.3 t/ha, compared with 5.7t for 'Manik'. Other valuable mutants were found showing long grain, less shattering, earlier maturity, and glutinous endosperm. One mutant, resistant to brown plant hopper yields 6.3t/ha. (author)

  11. X-rays sensitive mammalian cell mutant

    Utsumi, Hiroshi

    1982-01-01

    A phenomenon that in x-ray-sensitive mammalian-cell mutants, cellular death due to x-ray radiation was not increased by caffeine, but on the contrary, the dead cells were resuscitated by it was discussed. The survival rate of mutant cells increased by caffein in a low concentration. This suggested that caffeine may have induced some mechanism to produce x-ray resistant mutant cells. Postirradiation treatment with caffeine increased considerably the survival rate of the mutant cells, and this suggested the existence of latent caffeine-sensitive potentially lethal damage repair system. This system, after a few hours, is thought to be substituted by caffeine-resistant repair system which is induced by caffeine, and this may be further substituted by x-ray-resistant repair system. The repair system was also induced by adenine. (Ueda, J.)

  12. Generation and characterization of pigment mutants of ...

    acer

    2014-01-08

    Jan 8, 2014 ... aquatic ecosystems were studied. In the present ... logy and photosynthesis research (Stolbov, 1995;. Pedersen ... Microalgal strain and cultivation conditions ..... evaluated for their ecotoxicological effects using 124y-1 mutant.

  13. Characterization of a Synechocystis double mutant lacking the photosystem II assembly factors YCF48 and Sll0933

    Rengstl, B.; Knoppová, Jana; Komenda, Josef; Nickelsen, J.

    2013-01-01

    Roč. 237, č. 2 (2013), s. 471-480 ISSN 0032-0935 R&D Projects: GA ČR GBP501/12/G055; GA MŠk(CZ) ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : Complex assembly * Cyanobacteria * Photosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 3.376, year: 2013

  14. Characterization of a double deletion mutant of Fusarium verticillioides lacking two putative trehalose-6-phosphate phosphatase genes

    Fusarium verticillioides is a fungal pathogen that commonly infects the stalk, ear, and kernels of corn and can produce fumonisins, a family of mycotoxins linked to disease in livestock and humans. Our goal is to characterize the role of the disaccharide trehalose in growth and stress response in F....

  15. Lack of Correlation Between β-Lactamase Production and Susceptibility to Cefamandole or Cefoxitin Among Spontaneous Mutants of Enterobacteriaceae

    Ott, John L.; Turner, J. R.; Mahoney, David F.

    1979-01-01

    A large number of cultures of gram-negative bacteria were examined for their susceptibility to various concentrations of cefamandole, cefoxitin, carbenicillin, and nalidixic acid. Heterogeneity of susceptibility was demonstrated in individual cultures to all of these antibiotics. Resistant clones isolated from cefamandole or cefoxitin plates were examined for β-lactamase production. Approximately 13% of 262 resistant clones acquired the ability to produce a β-lactamase. Examination of the substrate profile of the β-lactamases from some of these clones revealed no change in the specific activity of these enzymes for cefamandole, cephaloridine, or compound 87/312 as compared with their parental enzymes. This study clearly shows that some resistant clones do not produce β-lactamases, whereas some susceptible strains produced significant amounts of these enzymes. We conclude from these findings that little correlation exists between β-lactamase production and decreased susceptibility to cefamandole or cefoxitin. The results suggest the possibility that characteristics other than β-lactamase production may be responsible for resistance in Enterobacteriaceae. PMID:311615

  16. Construction and characterization of a double deletion mutant of Fusarium verticillioides lacking two putative trehalose-6-phosphate phosphatase genes

    Fusarium verticillioides is a fungal pathogen that commonly infects the stalk, ear, and kernels of corn and can produce fumonisins, a family of mycotoxins linked to disease in livestock and humans. Our goal is to characterize the role of the disaccharide trehalose in growth and stress response in F....

  17. Ophthalmic acid accumulation in an Escherichia coli mutant lacking the conserved pyridoxal 5'-phosphate-binding protein YggS.

    Ito, Tomokazu; Yamauchi, Ayako; Hemmi, Hisashi; Yoshimura, Tohru

    2016-12-01

    Escherichia coli YggS is a highly conserved pyridoxal 5'-phosphate (PLP)-binding protein whose biochemical function is currently unknown. A previous study with a yggS-deficient E. coli strain (ΔyggS) demonstrated that YggS controls l-Ile- and l-Val-metabolism by modulating 2-ketobutyrate (2-KB), l-2-aminobutyrate (l-2-AB), and/or coenzyme A (CoA) availability in a PLP-dependent fashion. In this study, we found that ΔyggS accumulates an unknown metabolite as judged by amino acid analyses. LC/MS and MS/MS analyses of the compound with propyl chloroformate derivatization, and co-chromatography analysis identified this compound as γ-l-glutamyl-l-2-aminobutyryl-glycine (ophthalmic acid), a glutathione (GSH) analogue in which the l-Cys moiety is replaced by l-2-AB. We also determine the metabolic consequence of the yggS mutation. Absence of YggS initially increases l-2-AB availability, and then causes ophthalmic acid accumulation and CoA limitation in the cell. The expression of a γ-glutamylcysteine synthetase and a glutathione synthetase in a ΔyggS background causes high-level accumulation of ophthalmic acid in the cells (∼1.2 nmol/mg cells) in a minimal synthetic medium. This opens the possibility of a first fermentative production of ophthalmic acid. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Action potential generation in the small intestine of W mutant mice that lack interstitial cells of Cajal

    Malysz, J; Thuneberg, L; Mikkelsen, Hanne Birte

    1996-01-01

    significantly changed. Neither FLC nor MLC were part of a network nor did they form specialized junctions with neighboring cells as ICC do. Hence no cell type had replaced ICC at their normal morphological position associated with Auerbach's plexus. ICC were present in W/Wv mice at the deep muscular plexus...

  19. Phenotypic and epistatic grouping of hypo- and hyper-rec mus mutants in Aspergillus.

    Kafer, E; Chae, S K

    1994-03-01

    The mutants musK to musS of Aspergillus nidulans are sensitive to methyl-methanesulfonate (MMS) and several of them are meiotic-defective and alter mitotic recombination frequencies. All were found to be cross-sensitive to 4-nitro-quinoline-N-oxide (4-NQO) but unexpectedly none of them was hypersensitive to gamma-rays and few to UV light. Double mus; uvs mutants were constructed to test for interactions with uvs mutations of the four epistatic groups of Aspergillus, "UvsF", "UvsC", "UvsI", and "UvsB". All meiotic-defective mus mutations caused some lethal interactions, usually with uvsF. None of them showed epistasis with UvsF or UvsB group mutants and one, musO, may represent a new group. Three mus mutations that affect recombination were assigned to the UvsC group, namely musN and K, and also musL which is recombination-defective and closely resembles uvsC. While uvsC mutants are mutators and lack UV-mutagenesis, most mus mutants had no effects on mutation. Only musR, which appeared epistatic with uvsI, showed reduced UV-reversion frequencies similar to uvsI. The recombination-proficient mus mutants appeared to be epistatic with more than one group, but in several cases sensitivities were slight and overlaps insufficient to obtain corroborating results with MMS and 4-NQO.

  20. Functional Loss of Bmsei Causes Thermosensitive Epilepsy in Contractile Mutant Silkworm, Bombyx mori

    Nie, Hongyi; Cheng, Tingcai; Huang, Xiaofeng; Zhou, Mengting; Zhang, Yinxia; Dai, Fangyin; Mita, Kazuei; Xia, Qingyou; Liu, Chun

    2015-07-01

    The thermoprotective mechanisms of insects remain largely unknown. We reported the Bombyx mori contractile (cot) behavioral mutant with thermo-sensitive seizures phenotype. At elevated temperatures, the cot mutant exhibit seizures associated with strong contractions, rolling, vomiting, and a temporary lack of movement. We narrowed a region containing cot to ~268 kb by positional cloning and identified the mutant gene as Bmsei which encoded a potassium channel protein. Bmsei was present in both the cell membrane and cytoplasm in wild-type ganglia but faint in cot. Furthermore, Bmsei was markedly decreased upon high temperature treatment in cot mutant. With the RNAi method and injecting potassium channel blockers, the wild type silkworm was induced the cot phenotype. These results demonstrated that Bmsei was responsible for the cot mutant phenotype and played an important role in thermoprotection in silkworm. Meanwhile, comparative proteomic approach was used to investigate the proteomic differences. The results showed that the protein of Hsp-1 and Tn1 were significantly decreased and increased on protein level in cot mutant after thermo-stimulus, respectively. Our data provide insights into the mechanism of thermoprotection in insect. As cot phenotype closely resembles human epilepsy, cot might be a potential model for the mechanism of epilepsy in future.

  1. Impact of petrochemicals on the photosynthesis of Halophila ovalis using chlorophyll fluorescence

    Ralph, P.J.; Burchett, M.D.

    1998-01-01

    Laboratory-cultured Halophila ovalis showed tolerance to petrochemical exposure up to 1% (w/v) solution of Bass Strait crude oil, an oil dispersant (Corexit 9527) and a mixture of crude oil and dispersant. Quantum yield, as measured by chlorophyll fluorescence, was the most sensitive measure of the photosynthetic processes affected by petrochemical. The results indicated clearly that chlorophyll fluorescence was effective at monitoring the onset and development of stress and recovery of H. ovalis when exposed to crude oil, dispersant and a mixture of the two compounds. Photosynthetic pigment content generally confirmed the chlorophyll fluorescence response; however, several anomalies occurred. (author)

  2. Magnetic field dependence of the current flowing in the spin-coated chlorophyll thin films

    Aji, J. R. P.; Kusumandari; Purnama, B.

    2018-03-01

    The magnetic dependence of the current flowing in the spin coated chlorophyll films on a patterned Cu PCB substrate has been presented. Chlorophyll was isolated from Spirulina sp and deposited by spin coated methods. The reducing of current by the change of magnetic field (magneto conductance effect) was performed by inducing the magnetic field parallel to the inplane of film at room temp. The magnetoconductance ratio decreases as the increase of voltage. It was indicated that the origin of carrier charge in chlorophyll films should be different with the carrier charge injection (electron).

  3. Influence of frequent magnetic field on chlorophyll content in leaves of sugar beet plants

    Rochalska, M.

    2005-01-01

    Chlorophyll content in plant leaves is correlated with the yield and nitrogen content in plants. Non-destructive investigations of chlorophyll content in leaves of 3 varieties of sugar beet grown from seeds revealed that a low frequent magnetic field, acting independently or in combination with other methods of seed improvement, increased chlorophyll content in leaves of the investigated plants. The treatment with the magnetic field increased nitrogen content in the examined plants. The effect was not connected with environmental conditions during vegetation seasons. (author)

  4. Analysis of chlorophyll mutations induced by γ-rays in barley (hordeum vulgare)

    Wang Cailian; Shen Mei; Xu Gang; Zhao Kongnan; Chen Qiufang

    1991-06-01

    Thirty varieties of dormant barley seeds were irradiated with 137 Cs γ-rays. Dose-effect relations of chlorophyll mutation frequency in M 2 seedling and differences resulting from cultured types or radiosensitive types were investigated. Experimental results show that the relations between chlorophyll mutation frequency and doses can be fitted by a linear regression equation Y = A + BX. According to analysis of covariance, there is no considerable difference in various cultured types, but the difference of five different radiosensitive types is remarkable. The sensitive and intermediate types need much lower doses than other types to induce maximum chlorophyll mutation

  5. Molecular analysis of waxy mutants in rice

    Yatou, O.; Amano, E.

    1990-01-01

    Full text: The 'waxy' gene is a structural gene coding a glycosyl transferase which synthesises amylose in the endosperm tissue. 'Non-waxy' rice cultivars have an active gene and their amylose content is 18-25% depending upon gene performance and modifier genes. In 'waxy' rice, no amylose is found because the enzyme is absent. In mutants induced by gamma rays, neutrons, EI or EMS, amylose content ranged from 0 to 20%, i.e. there are intermediate phenotypes as well. Some of them had the same amount of the enzyme as a 'non-waxy' cultivar, even fully 'waxy' mutants showed a certain amount of the enzyme. This suggests that in mutants there may be no structural change in the enzyme gene but the enzyme produced might be less active. By molecular analysis of the mutants' genes it was found that only two mutants induced by thermal neutrons show structural alterations, the changes in other mutants are either too small to be detected by Southern analysis or are outside the structural gene in question. (author)

  6. Commercialization Of Orchid Mutants For Floriculture Industry

    Sakinah Ariffin; Zaiton Ahmad

    2014-01-01

    Orchids are the main contributors to cut flower industry in Malaysia with an existing good market and a huge business potential. Orchid industry has been established in Malaysia since 1960s but only started to develop and expand since 1980s. Continuous development of new orchid varieties is essential to meet customers' demands. Orchid mutagenesis research using gamma irradiation at Malaysian Nuclear Agency has successfully generated a number of new orchid varieties with commercial potentials. Therefore, Nuclear Malaysia has collaborated with an industrial partner, Hexagon Green Sdn Bhd (HGSB), to carry out commercialization research on these mutants under a Technofund project entitled 'Pre-Commercialization of Mutant Orchids for Cut Flowers Industry' from July 2011 to July 2014. Through this collaboration, Dendrobium orchid mutant plants developed by Nuclear Malaysia were transferred to HGSB's commercial orchid nursery at Bukit Changgang Agrotechnology Park, Banting, Selangor, for mass-propagation. The activities include evaluations on plant growth performance, flower quality, post harvest and market potential of these mutants. Mutants with good field performance have been identified and filed for Plant Variety Protection (PVP) with Department of Agriculture Malaysia. This paper describes outputs from this collaboration and activities undertaken in commercializing these mutants. (author)

  7. Electron transfer reactions involving porphyrins and chlorophyll a

    Neta, P.; Scherz, A.; Levanon, H.

    1979-01-01

    Electron transfer reactions involving porphyrins (P) and quinones (Q) have been studied by pulse radiolysis. The porphyrins used were tetraphenylporphyrin (H 2 TPP), its tetracarboxy derivative (H 2 TCPP), the sodium and zinc compounds (Na 2 TPP and ZnTPP), and chlorophyll a (Chl a). These compounds were found to be rapidly reduced by electron transfer from (CH 3 ) 2 CO - . Reduction by (CH 3 ) 2 COH was rapid in aqueous solutions but relatively slow in i-PrOH solutions. Transient spectra of the anion radicals were determined and, in the case of H 2 TCPP - ., a pK = 9.7 was derived for its protonation. Electron-transfer reactions from the anion radical of H 2 TCPP to benzoquinone, duroquinone, 9,10-anthraquinone 2-sulfonate, and methylviologen occur in aqueous solutions with rate constants approx. 10 7 -10 9 M -1 s -1 which depend on the pH and the quinone reduction potential. Reactions of Na 2 TPP - ., ZnTPP - ., and Chl a - . with anthraquinone in basic i-PrOH solutions occur with rate constants approx. 10 9 M -1 s -1 . The spectral changes associated with these electron-transfer reactions as observed over a period of approx. 1 ms indicated, in some cases, the formation of an intermediate complex [P...Q - .]. 8 figures, 2 tables

  8. Genetic control of some morphological mutants in sunflower [Helianthus annuus L.

    Nabipour, A.; Sarrafi, A.; Yazdi-Samadi, B.

    2004-01-01

    Inheritance study of induced mutants is an important tool in genetic and breeding programs. Sunflower is one of the most important oil crops for which mutant collection is meager. Seeds of sunflower line AS-613 were irradiated with gamma rays and mutant phenotypes were traced until M4 generation. In M5 generation, the following traits were studied: dwarfing, branching, leaf shape, albinism, rosette, lack of apex and alternative leaves. In most cases, the mutated characters were controlled by a single recessive gene, while in two cases they were controlled by two recessive genes. In M5 progenies, segregation for two albino, one alternative leaves, one dwarfism, 5 branching, one rosette, 2 lacks of apex and 5 leaf shape mutants was recorded. Amongst five cases of branching, one was controlled by two recessive genes, where at least one homozygote recessive locus was necessary for branching. In one case, the lack of apex was controlled by two recessive genes and even only one dominant allele could provoke the normal plant [it

  9. From one body mutant to one cell mutant. A progress of radiation breeding in crops

    Nagatomi, Shigeki

    1996-01-01

    An effective method was established to obtain non-chimeral mutants with wide spectrum of flower colors, regenerated from floral organs on which mutated sectors were come out on chronic irradiated plants. By this way, six mutant varieties of flower colors have been selected from one pink flower of chrysanthemum, and cultivated for cut-flower production. By the same method, 3 mutant varieties with small and spray type flowers were selected in Eustoma. Mutant varieties such as a rust disease resistant in sugarcane, 6 dwarfs in Cytisus and pure-white mushroom in velvet shank have been selected successively for short period. (J.P.N.)

  10. E2-EPF UCP regulates stability and functions of missense mutant pVHL via ubiquitin mediated proteolysis.

    Park, Kyeong-Su; Kim, Ju Hee; Shin, Hee Won; Chung, Kyung-Sook; Im, Dong-Soo; Lim, Jung Hwa; Jung, Cho-Rok

    2015-10-26

    Missense mutation of VHL gene is frequently detected in type 2 VHL diseases and linked to a wide range of pVHL functions and stability. Certain mutant pVHLs retain ability to regulate HIFs but lose their function by instability. In this case, regulating of degradation of mutant pVHLs, can be postulated as therapeutic method. The stability and cellular function of missense mutant pVHLs were determine in HEK293T transient expressing cell and 786-O stable cell line. Ubiquitination assay of mutant VHL proteins was performed in vitro system. Anticancer effect of adenovirus mediated shUCP expressing was evaluated using ex vivo mouse xenograft assay. Three VHL missense mutants (V155A, L158Q, and Q164R) are directly ubiquitinated by E2-EPF UCP (UCP) in vitro. Mutant pVHLs are more unstable than wild type in cell. Missense mutant pVHLs interact with UCP directly in both in vitro and cellular systems. Lacking all of lysine residues of pVHL result in resistance to ubiquitination thereby increase its stability. Missense mutant pVHLs maintained the function of E3 ligase to ubiquitinate HIF-1α in vitro. In cells expressing mutant pVHLs, Glut-1 and VEGF were relatively upregulated compared to their levels in cells expressing wild-type. Depletion of UCP restored missense mutant pVHLs levels and inhibited cell growth. Adenovirus-mediated shUCP RNA delivery inhibited tumor growth in ex vivo mouse xenograft model. These data suggest that targeting of UCP can be one of therapeutic method in type 2 VHL disease caused by unstable but functional missense mutant pVHL.

  11. A Phenomenological Study on Lack of Motivation

    Educational Research and Reviews, 2013

    2013-01-01

    The aim of this research is to point out the underlying reasons about the lack of motivation at academic activities concerning Attribution Theory. Attribution Theory trys to understand how the people answer "why" question and how they do casual explanations. This research is a qualitative based research. It used the phenomenological…

  12. Phosphoribosyl diphosphate synthetase-independent NAD de novo synthesis in Escherichia coli: a new phenotype of phosphate regulon mutants

    Hove-Jensen, Bjarne

    1996-01-01

    Phosphoribosyl diphosphate-lacking (Δprs) mutant strains of Escherichia coli require NAD, guanosine, uridine, histidine, and tryptophan for growth. NAD is required by phosphoribosyl diphosphate-lacking mutants because of lack of one of the substrates for the quinolinate phosphoribosyltransferase...... reaction, an enzyme of the NAD de novo pathway. Several NAD-independent mutants of a host from which prs had been deleted were isolated; all of them were shown to have lesions in the pstSCAB-phoU operon, in which mutations lead to derepression of the Pho regulon. In addition NAD-independent growth...... was dependent on a functional quinolinate phosphoribosyltransferase. The prs suppressor mutations led to the synthesis of a new phosphoryl compound that may act as a precursor for a new NAD biosynthetic pathway. This compound may be synthesized by the product of an unknown phosphate starvation-inducible gene...

  13. An evaluation of the problems of chlorophyll retrieval from ocean colour, for case 2 waters

    Sathyendranath, S.; Prieur, L.; Morel, A.

    A reflectance model is presented that takes into account the spectral signatures of phytoplankton, dissolved organic matter and non-chlorophyllous particles. The model is validated by comparison with observed reflectance spectra. It is then used...

  14. Chlorophyll-a, Aqua MODIS, NPP, 0.0125 degrees, Indonesia

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  15. Chlorophyll-a, Aqua MODIS, OSU DB, 0.0125 degrees, West US

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua satellite. Measurements are gathered by the Moderate Resolution Imaging...

  16. Chlorophyll-a, Aqua MODIS, NPP, 0.025 degrees, Pacific Ocean, EXPERIMENTAL

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  17. Chlorophyll-a, Aqua MODIS, NPP, 0.0125 degrees, Gulf of Mexico, EXPERIMENTAL

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  18. Chlorophyll-a, Aqua MODIS, NPP, 0.05 degrees, Global, Science Quality

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  19. Chlorophyll-a, Aqua MODIS, NPP, 0.0125 degrees, East US, EXPERIMENTAL

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  20. Chlorophyll-a, Aqua MODIS, NPP, 0.0125 degrees, West US, EXPERIMENTAL

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Aqua Spacecraft. Measurements are gathered by the Moderate Resolution Imaging...

  1. TRACKING CHANGES IN CHLOROPHYLL AND CAROTENOIDS IN THE PRODUCTION PROCESS OF FROZEN SPINACH PURÉE

    Andrea Mendelová

    2014-02-01

    Full Text Available Spinach is in the professional and general public considered highly nutritious vegetable with many beneficial effects on human health. It is a rich source of antioxidant active substances, especially chlorophyll, carotenoids, flavonoids and minerals especially zinc and copper. This work studies the changes of chlorophyll and carotenoids that occur after mass production technology of freezing at -37 °C. Before freezing was used blanching operation. In this work we used a variety Boeing, Boa, Beaver, Hudson and Chica. The highest content of all monitored parameters are found in fresh leaves of sampled Hudson. We found that within the processing decreases chlorophyll in 16.6%, 13.8% of chlorophyll b and carotenoids of 6.15%. This decrease was in all cases statistically significant.

  2. Seasonal variability of sea surface chlorophyll-a of waters around ...

    days during 1978--1986 are processed to produce sea surface chlorophyll maps ... shallow water areas, in particular waters in Palk Bay and Gulf of Mannar, should be carried out in order .... The circulation penetrates deeper, affecting the.

  3. Chlorophyll 'a' particulate organic carbon and suspended load from the mangrove areas of Cochin backwaters

    Sheeba, P.; Devi, K.S.; Balasubramanian, T.; Sankaranarayanan, V.N.

    Chlorophyll 'a' Particulate Organic Carbon and suspended load were estimated for one year from two distinct mangrove areas of Cochin backwaters, viz. Puthuvypeen and Nettoor. Environmental parameters like tau degrees C, S ppt and pH were also...

  4. HAAR TRANSFORM BASED ESTIMATION OF CHLOROPHYLL AND STRUCTURE OF THE LEAF

    Abhinav Arora; R. Menaka; Shivangi Gupta; Archit Mishra

    2013-01-01

    In this paper, the health of a plant is estimated using various non-destructive Image Processing Techniques. Chlorophyll content was detected based on colour Image Processing. The Haar transform is applied to get size of leaf and the parameters.

  5. Comparison of chlorophyll in the Red Sea derived from MODIS-Aqua and in vivo fluorescence

    Brewin, Robert J W; Raitsos, Dionysios E.; Pradhan, Yaswant; Hoteit, Ibrahim

    2013-01-01

    The Red Sea is a unique marine environment but relatively unexplored. The only available long-term biological dataset at large spatial and temporal scales is remotely-sensed chlorophyll observations (an index of phytoplankton biomass) derived using

  6. Effect of gamma radiation on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa

    Martin Moreno, C.; Fernandez Gonzalez, J.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first b chlorophyll affected to a greater extent than a chlorophyll. Net photosynthesis and respiration decline throughout the time of the observation after irradiation, this depressing effect being much more remarkable for the first one. Met photosynthesis inhibition levels of about 30% are got only five hours post irradiation at a dose of 5000 Gy. Radio estimation by low doses, although obtained in some cases for tho 10 Gy dose, has not been statistically confirmed. (Author) 23 refs

  7. Chlorophyll Detection and Mapping of Shallow Water Impoundments Using Image Spectrometry

    Artigas, F.; Pechmann, I.; Marti, A.; Yao, N.; Pechmann, I.

    2008-01-01

    There exists a common perception that chlorophyll a concentrations in tidal coastal waters are unsuitable to be captured by remote sensing techniques because of high water turbidity. In this study, we use band index measurements to separate active chlorophyll pigments from other constituents in the water. Published single- and multiband spectral indices are used to establish a relationship between algal chlorophyll concentration and reflectance data. We find an index which is suitable to map chlorophyll gradients in the impoundments, ditches, and associated waterways of the Hackensack Meadow lands (NJ, USA). The resulting images clearly depict the spatial distribution of plant pigments and their relationship with the biological conditions of the waters in the estuary. Since these biological conditions are often determined by land usage, the methods in this paper provide a simple tool to address water quality management issues in fragmented urban estuaries.

  8. Are the Satellite-Observed Narrow, Streaky Chlorophyll Filaments Locally Intensified by the Submesoscale Processes?

    2015-11-05

    HIS I’OR’A CANCELS AND SUPERSEOFS Al l PRFV•OUS VERSIONS ARE THE SATELLITE-OBSERVED NARROW, STREAKY CHLOROPHYLL FILAMENTS LOCALLY INTENSIFIED BY...AUGUST 2003 cold, dense jeto C 17 16 15 14 13 122.4W 122W 122.4W 122W warm, anticyclonic eddy CHLOROPHYLL 122.4W 122W 122.4W 122W 122.4W 122W filament...122.4W 122W mg/m 3 10 4 2 1 0.4 0.2 Figure 1. MODIS-Aqua SST and Chlorophyll a images for August 2003. Black lines on MODIS SST and Chlorophyll a

  9. Chlorophyll catalyse the photo-transformation of carcinogenic benzo[a]pyrene in water

    Luo, Lijuan; Lai, Xueying; Chen, Baowei; Lin, Li; Fang, Ling; Tam, Nora F. Y.; Luan, Tiangang

    2015-01-01

    Algal blooms cause great damage to water quality and aquaculture. However, this study showed that dead algal cells and chlorophyll could accelerate the photo-transformation of benzo[a]pyrene (BaP), a ubiquitous and persistent pollutant with potently mutagenic and carcinogenic toxicities, under visible light irradiation. Chlorophyll was found to be the major active substance in dead algal cells, and generated a high level of singlet oxygen to catalyse the photo-transformation of BaP. According to various BaP metabolites formed, the degradation mechanism was proposed as that chlorophyll in dead algal cells photo-oxidized BaP to quinones via photocatalytic generation of singlet oxygen. The results provided a good insight into the role of chlorophyll in the photo-transformation of organic contaminants and could be a possible remediation strategy of organic pollutants in natural environment. PMID:26239357

  10. An FTIR study on the chlorophyll and apoprotein aggregation states in LHCII due to solvent effects

    Smit, Jacoba E

    2012-07-01

    Full Text Available Photosynthesis provides us with the most abundant and efficient light-harvesting systems found in nature. The photosynthetic process is very much dependent on the aggregation state of the chlorophylls and secondary conformational structure...

  11. Relationships between Concentrations of Phytoplankton Chlorophyll a and Total Nitrogen in Ten U.S. Estuaries

    This presentation focuses on the summertime response of phytoplankton chlorophyll to nitrogen concentrations in the upper water columns of ten U.S. estuaries. Using publicly available data from monitoring programs, regression relationships have been developed between summer surfa...

  12. VIIRSN Level-3 Standard Mapped Image, Chlorophyll a, Daily, 4km

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from the NPP -Suonomi Spacecraft. Measurements are gathered by the VIIRS instrument carried aboard the...

  13. Five Year Mean Surface Chlorophyll Estimates in the Northern Gulf of Mexico for 2005 through 2009

    National Oceanic and Atmospheric Administration, Department of Commerce — These images were created by combining the mean surface chlorophyll estimates to produce seasonal representations for winter, spring, summer and fall. Winter...

  14. Subsurface chlorophyll maxima in the north-western Bay of Bengal

    Sarma, V.V.; Aswanikumar, V.

    of thermocline suggests that the formation of the subsurface maximum is influencEd. by the presence of seasonal thermocline. Further the subsurface chlorophyll maximum is noticed within the depth ranges of ammonium maximum and nitracline, suggesting...

  15. Chlorophyll-a, Terra MODIS, OSU DB, 0.0125 degrees, West US, EXPERIMENTAL

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration data from NASA's Terra satellite. Measurements are gathered by the Moderate Resolution Imaging...

  16. Thermocline Regulated Seasonal Evolution of Surface Chlorophyll in the Gulf of Aden

    Hoteit, Ibrahim; Yao, Fengchao

    2015-01-01

    The Gulf of Aden, although subject to seasonally reversing monsoonal winds, has been previously reported as an oligotrophic basin during summer, with elevated chlorophyll concentrations only occurring during winter due to convective mixing. However

  17. Extraction of chlorophyll from pandan leaves using ethanol and mass transfer study

    Putra Meilana Dharma

    2017-01-01

    Full Text Available Green pigments are used in many industrial branches including food, drinks, soap and cosmetics. Chlorophyll can substitute synthetic dyes which may affect health. Chlorophyll can be extracted from pandan leaves; the pandan crop grows in many tropical areas. The effects of temperature, 30–70°C and agitation speed, 100–400 rpm on chlorophyll extraction from pandan leaves, using ethanol and the evaluation of mass transfer coefficient, using dimensionless analysis were investigated. The optimal conditions of extraction was obtained at 60°C and 300 rpm; the chlorophyll concentration was 107.1 mg L-1. The volumetric mass transfer coefficient increased with the temperature and agitation speed. Determination of volumetric mass transfer coefficient and dimensionless correlations are useful for further process development or industrial applications.

  18. Officially released mutant varieties in China

    Liu, L.; Van Zanten, L.; Shu, Q.Y.; Maluszynski, M.

    2004-01-01

    The use of mutation techniques for crop improvement in China has a long and well-established tradition of more than 50 years. As the result of intensive research in many institutes dealing with application of nuclear technologies more than 620 cultivars of 44 crop species have been released. Numerous mutant varieties have been grown on a large scale bringing significant economic impact, sustaining crop production and greatly contributing to increase of food production also in stress prone areas of the country. However, there is still missing information not only on the number of mutant varieties released in particular crop species but also on mutagens applied, selection approaches and on the use of mutants in cross breeding. Numerous Chinese scientists collected and systematized this information. Results of their work were often published in local scientific journals in the Chinese language and as such were unavailable to breeders from other countries. Having this in mind, we requested Dr. Liu Luxiang, the Director of the Department of Plant Mutation Breeding and Genetics, Institute for Application of Atomic Energy, Chinese Academy of Agricultural Sciences in Beijing to help us in finding as much information as possible on mutant varieties officially released in China. The data has been collected in close collaboration with his colleagues from various institutions all over the country and then evaluated, edited and prepared for publication by our team responsible for the FAO/IAEA Database of Officially Released Mutant Varieties. We would like to thank all Chinese colleagues who contributed to this list of Chinese mutant varieties. We hope that this publication will stimulate plant breeders in China to collect more information on released mutant varieties and especially on the use of mutated genes in cross breeding. (author)

  19. Development of high yielding mutants in lentil

    Rajput, M.A.; Sarwar, G.; Siddiqui, K.A.

    2001-01-01

    Full text: Lentil (Lens culinaris Medik.) locally known as Masoor, is the second most important rabi pulse crop, after chickpea, in Pakistan. It is cultivated on an area of over 63,400 ha, which constitutes about 4.83% of the total area under pulses. The annual production of the crop is 28,200 tones with an average yield of 445 kg/ha. Yield at the national level is very low, about one-half of the world's yield, which is mainly due to non-availability of high yield potential genotypes. Keeping in view the importance of mutants in developing a large number of new varieties, an induced mutations programme was initiated at AEARC, Tandojam during 1987-88, to develop high yielding varieties in lentil. For this, seeds of two lentil varieties, 'Masoor-85' and 'ICARDA-8' had been irradiated with gamma-rays ranging from 100-600 Gy in NIAB, Faisalabad during 1990. Selections were made in M2 on the basis of earliness, plant height, branches/plant and 100 grain weight. After confirming these mutants in M3 they were promoted in station yield trials and studied continuously for three consecutive years (1993- 1995). Overall results revealed that these mutants have consistent improvement of earliness in flowering and maturity. Plant height also increased in all mutant lines except AEL 23/40/91 where reduction in this attribute was observed as compared to parent variety. Mutant lines AEL 49/20/91 and AEL 13/30/91 showed improvement in 100 grain weight. The improvement of some agronomic characters enhanced the yield of mutant lines in comparison to parent varieties (Masoor-85 and ICARDA-8). The diversity in yield over the respective parents was computed from 6.94 to 60.12%. From these encouraging results it is hoped that mutant lines like AEL 12/30/91 and AEL 49/20/91 may serve as potential lentil genotypes in future. (author)

  20. Vegetation chlorophyll estimates in the Amazon from multi-angle MODIS observations and canopy reflectance model

    Hilker, Thomas; Galvão, Lênio Soares; Aragão, Luiz E. O. C.; de Moura, Yhasmin M.; do Amaral, Cibele H.; Lyapustin, Alexei I.; Wu, Jin; Albert, Loren P.; Ferreira, Marciel José; Anderson, Liana O.; dos Santos, Victor A. H. F.; Prohaska, Neill; Tribuzy, Edgard; Barbosa Ceron, João Vitor; Saleska, Scott R.; Wang, Yujie; de Carvalho Gonçalves, José Francisco; de Oliveira Junior, Raimundo Cosme; Cardoso Rodrigues, João Victor Figueiredo; Garcia, Maquelle Neves

    2017-06-01

    As a preparatory study for future hyperspectral missions that can measure canopy chemistry, we introduce a novel approach to investigate whether multi-angle Moderate Resolution Imaging Spectroradiometer (MODIS) data can be used to generate a preliminary database with long-term estimates of chlorophyll. MODIS monthly chlorophyll estimates between 2000 and 2015, derived from a fully coupled canopy reflectance model (ProSAIL), were inspected for consistency with eddy covariance fluxes, tower-based hyperspectral images and chlorophyll measurements. MODIS chlorophyll estimates from the inverse model showed strong seasonal variations across two flux-tower sites in central and eastern Amazon. Marked increases in chlorophyll concentrations were observed during the early dry season. Remotely sensed chlorophyll concentrations were correlated to field measurements (r2 = 0.73 and r2 = 0.98) but the data deviated from the 1:1 line with root mean square errors (RMSE) ranging from 0.355 μg cm-2 (Tapajós tower) to 0.470 μg cm-2 (Manaus tower). The chlorophyll estimates were consistent with flux tower measurements of photosynthetically active radiation (PAR) and net ecosystem productivity (NEP). We also applied ProSAIL to mono-angle hyperspectral observations from a camera installed on a tower to scale modeled chlorophyll pigments to MODIS observations (r2 = 0.73). Chlorophyll pigment concentrations (ChlA+B) were correlated to changes in the amount of young and mature leaf area per month (0.59 ≤ r2 ≤ 0.64). Increases in MODIS observed ChlA+B were preceded by increased PAR during the dry season (0.61 ≤ r2 ≤ 0.62) and followed by changes in net carbon uptake. We conclude that, at these two sites, changes in LAI, coupled with changes in leaf chlorophyll, are comparable with seasonality of plant productivity. Our results allowed the preliminary development of a 15-year time series of chlorophyll estimates over the Amazon to support canopy chemistry studies using future

  1. DAYTIME VARIATIONS OF CHLOROPHYLL A FLUORESCENCE IN PAU D'ALHO SEEDLINGS

    Bacarin, Marcos Antonio; Martinazzo, Emanuela Garbin; Cassol, Daniela; Falqueto, Antelmo Ralph; Silva, Diolina Moura

    2016-01-01

    ABSTRACT Analysis of transient and modulated fluorescence of chlorophyll a were made at one-hour intervals during an eight-hour period starting at 07:30h aiming to study mechanisms of photoprotection against high radiation and temperature in Gallesia integrifolia plants. Seeds were germinated inside plastic pots containing soil as substrate. At 120 days after emergence, chlorophyll fluorescence measurements were performed using Handy-PEA and FMS2 fluorometers. During the course of a day, an i...

  2. Impact of measurement uncertainties on determination of chlorophyll-specific absorption coefficient for marine phytoplankton

    McKee, D.; Röttgers, R.; Neukermans, G.; Calzado, V.S.; Trees, C.; Ampolo-Rella, M.; Neil, C.; Cunningham, A.

    2014-01-01

    Understanding variability in the chlorophyll-specific absorption of marine phytoplankton, aph*Chl (λ), is essential for primary production modelling, calculation of underwater light field characteristics, and development of algorithms for remote sensing of chlorophyll concentrations. Previous field and laboratory studies have demonstrated significant apparent variability in aph*Chl (λ) for natural samples and algal cultures. However, the potential impact of measurement uncertain...

  3. Characterization of [8-ethyl]-chlorophyll c3 from Emiliania huxleyi.

    Álvarez, Susana; Zapata, Manuel; Garrido, José L; Vaz, Belén

    2012-06-04

    We report herein the isolation and complete characterization of a member of the chlorophyll c family, designated as [8-ethyl]-chlorophyll c(3) ([8-ethyl]-chl c(3)). Structural elucidation of this pigment rested on the analysis of mono- and bidimensional NMR, UV-VIS spectroscopy and ESI-MS data, and the configuration at the 13(2) position on chiral HPLC analysis.

  4. PIXE analysis of trace elements in relation to chlorophyll concentration in Plantago ovata Forsk

    Saha, Priyanka; Sen Raychaudhuri, Sarmistha; Chakraborty, Anindita; Sudarshan, Mathummal

    2010-01-01

    Plantago ovata Forsk - an economically important medicinal plant - was analyzed for trace elements and chlorophyll in a study of the effects of gamma radiation on physiological responses of the seedlings. Proton-induced X-ray emission (PIXE) technique was used to quantify trace elements in unirradiated and gamma-irradiated plants at the seedling stage. The experiments revealed radiation-induced changes in the trace element and chlorophyll concentrations.

  5. Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide

    Wernand, Marcel R.; van der Woerd, Hendrik J.; Gieskes, Winfried W. C.

    2013-01-01

    Marine primary productivity is an important agent in the global cycling of carbon dioxide, a major ‘greenhouse gas’, and variations in the concentration of the ocean's phytoplankton biomass can therefore explain trends in the global carbon budget. Since the launch of satellite-mounted sensors globe-wide monitoring of chlorophyll, a phytoplankton biomass proxy, became feasible. Just as satellites, the Forel-Ule (FU) scale record (a hardly explored database of ocean colour) has covered all seas and oceans – but already since 1889. We provide evidence that changes of ocean surface chlorophyll can be reconstructed with confidence from this record. The EcoLight radiative transfer numerical model indicates that the FU index is closely related to chlorophyll concentrations in open ocean regions. The most complete FU record is that of the North Atlantic in terms of coverage over space and in time; this dataset has been used to test the validity of colour changes that can be translated to chlorophyll. The FU and FU-derived chlorophyll data were analysed for monotonously increasing or decreasing trends with the non-parametric Mann-Kendall test, a method to establish the presence of a consistent trend. Our analysis has not revealed a globe-wide trend of increase or decrease in chlorophyll concentration during the past century; ocean regions have apparently responded differentially to changes in meteorological, hydrological and biological conditions at the surface, including potential long-term trends related to global warming. Since 1889, chlorophyll concentrations have decreased in the Indian Ocean and in the Pacific; increased in the Atlantic Ocean, the Mediterranean, the Chinese Sea, and in the seas west and north-west of Japan. This suggests that explanations of chlorophyll changes over long periods should focus on hydrographical and biological characteristics typical of single ocean regions, not on those of ‘the’ ocean. PMID:23776435

  6. Non-invasive method for in vivo detection of chlorophyll precursors

    Kristiansen, Kim Anker; Khrouchtchova, Anastassia; Stenbæk, Anne

    2009-01-01

    Traditionally chlorophyll (Chl) and Chl precursors have been studied in vitro or in leaf tissue at low temperature. These methods are destructive and make it impossible to work with the same individual plant later on. In this paper we present a method for in vivo detection of Chl and its precursors...... is compared to current methods. Furthermore, we report on optimization of the spectral scanning method with the aim to minimize the excitation light-evoked photo-conversion of the chlorophyll precursors....

  7. Thylakoid redox signals are integrated into organellar-gene-expression-dependent retrograde signalling in the prors1-1 mutant

    Luca eTadini

    2012-12-01

    Full Text Available Perturbations in organellar gene expression (OGE and the thylakoid redox state (TRS activate retrograde signalling pathways that adaptively modify nuclear gene expression (NGE, according to developmental and metabolic needs. The prors1-1 mutation in Arabidopsis down-regulates the expression of the nuclear gene Prolyl-tRNA Synthetase1 (PRORS1 which acts in both plastids and mitochondria, thereby impairing protein synthesis in both organelles and triggering OGE-dependent retrograde signalling. Because the mutation also affects thylakoid electron transport, TRS-dependent signals may likewise have an impact on the changes in NGE observed in this genotype. In this study, we have investigated whether signals related to TRS are actually integrated into the OGE-dependent retrograde signalling pathway. To this end, the chaos mutation (for chlorophyll a/b binding protein harvesting-organelle specific, which shows a partial loss of PSII antennae proteins and thus a reduction in PSII light absorption capability, was introduced into the prors1-1 mutant background. The resulting double mutant displayed a prors1-1-like reduction in plastid translation rate and a chaos-like decrease in PSII antenna size, whereas the hyper-reduction of the thylakoid electron transport chain, caused by the prors1-1 mutation, was alleviated, as determined by monitoring chlorophyll (Chl fluorescence and thylakoid phosphorylation. Interestingly, a substantial fraction of the nucleus-encoded photosynthesis genes down-regulated in the prors1-1 mutant are expressed at nearly wild-type rates in prors1-1 chaos leaves, and this recovery is reflected in the steady-state levels of their protein products in the chloroplast. We therefore conclude that signals related to photosynthetic electron transport and TRS, and indirectly to carbohydrate metabolism and energy balance, are indeed fed into the OGE-dependent retrograde pathway to modulate NGE and adjust the abundance of chloroplast proteins.

  8. Contribution of Co2+ in increasing chlorophyll a concentration of Nannochloropsis salina in controlled Conwy medium

    Hala, Y.; Taba, P.; Suryati, E.; Kasih, P.; Firman, N. F.

    2018-03-01

    A research in determining the contribution of Co2+ on the increase of chlorophyll a concentration of Nannochloropsis salina has been caried out. The cultivation of N. salina was conducted in the Conwy medium with a salinity of 5%o and 25%o and various Co2+ concentration (2, 4, and 8 ppm). In this research, Co2+ was exposed early in the cultivation of N. salina. The growth of N. salina was observed daily by counting the number of populations using a haemocytometer while the chlorophyll a concentration was determined by a Uv-Vis spectrophotometer. The results showed that the growth of N. salina in the control was higher than that in the medium containing Co2+. The optimum growth time was achieved on 15th days (5%) and 8th days (25%). In the cultivation medium with a salinity of 5%, Co2+ with a concentration of 2 ppm increased the chlorophyll a level while Co2+ with concentrations of 4 and 8 ppm decreased it. In the medium of cultivation with a salinity of 25%, the increase in chlorophyll a level was observed at Co2+ concentrations of 2 and 4 ppm whereas the decrease in chlorophyl a level was given at a concentration of 8 ppm. It can be concluded that at low concentrations, Co2+ increased the concentration of chlorophyll a in N. salina.

  9. Spatial-temporal variability of leaf chlorophyll and its relationship with cocoa yield

    Caique C. Medauar

    Full Text Available ABSTRACT The objective of this study was to evaluate the spatial-temporal variability of leaf chlorophyll index and its relationship with cocoa yield. The experiment was carried out in an experimental area of cocoa production located in Ilhéus, Bahia State, Brazil. Leaf chlorophyll content was measured in September, October, January, February, March and April in the 2014/2015 season, at each sampling point of a regular grid by using a portable chlorophyll meter. Under the same conditions, yield was evaluated and the data were submitted to descriptive statistics and a linear correlation study. Geostatistical analysis was used to determine and quantify the spatial and temporal variability of leaf chlorophyll index and yield. Leaf chlorophyll index varied over the period evaluated, but the months of February, March and April showed no spatial dependence in the study area, indicating absence of temporal stability. Cocoa monthly yield, except in January, presented high spatial variability. Under the conditions of this study, it was not possible to establish a relationship between leaf chlorophyll index and cocoa yield.

  10. Estimating chlorophyll content of spartina alterniflora at leaf level using hyper-spectral data

    Wang, Jiapeng; Shi, Runhe; Liu, Pudong; Zhang, Chao; Chen, Maosi

    2017-09-01

    Spartina alterniflora, one of most successful invasive species in the world, was firstly introduced to China in 1979 to accelerate sedimentation and land formation via so-called "ecological engineering", and it is now widely distributed in coastal saltmarshes in China. A key question is how to retrieve chlorophyll content to reflect growth status, which has important implication of potential invasiveness. In this work, an estimation model of chlorophyll content of S. alterniflora was developed based on hyper-spectral data in the Dongtan Wetland, Yangtze Estuary, China. The spectral reflectance of S. alterniflora leaves and their corresponding chlorophyll contents were measured, and then the correlation analysis and regression (i.e., linear, logarithmic, quadratic, power and exponential regression) method were established. The spectral reflectance was transformed and the feature parameters (i.e., "san bian", "lv feng" and "hong gu") were extracted to retrieve the chlorophyll content of S. alterniflora . The results showed that these parameters had a large correlation coefficient with chlorophyll content. On the basis of the correlation coefficient, mathematical models were established, and the models of power and exponential based on SDb had the least RMSE and larger R2 , which had a good performance regarding the inversion of chlorophyll content of S. alterniflora.

  11. Dustfall Effect on Hyperspectral Inversion of Chlorophyll Content - a Laboratory Experiment

    Chen, Yuteng; Ma, Baodong; Li, Xuexin; Zhang, Song; Wu, Lixin

    2018-04-01

    Dust pollution is serious in many areas of China. It is of great significance to estimate chlorophyll content of vegetation accurately by hyperspectral remote sensing for assessing the vegetation growth status and monitoring the ecological environment in dusty areas. By using selected vegetation indices including Medium Resolution Imaging Spectrometer Terrestrial Chlorophyll Index (MTCI) Double Difference Index (DD) and Red Edge Position Index (REP), chlorophyll inversion models were built to study the accuracy of hyperspectral inversion of chlorophyll content based on a laboratory experiment. The results show that: (1) REP exponential model has the most stable accuracy for inversion of chlorophyll content in dusty environment. When dustfall amount is less than 80 g/m2, the inversion accuracy based on REP is stable with the variation of dustfall amount. When dustfall amount is greater than 80 g/m2, the inversion accuracy is slightly fluctuation. (2) Inversion accuracy of DD is worst among three models. (3) MTCI logarithm model has high inversion accuracy when dustfall amount is less than 80 g/m2; When dustfall amount is greater than 80 g/m2, inversion accuracy decreases regularly and inversion accuracy of modified MTCI (mMTCI) increases significantly. The results provide experimental basis and theoretical reference for hyperspectral remote sensing inversion of chlorophyll content.

  12. Effect of PEG-6000 Imposed Water Deficit on Chlorophyll Metabolism in Maize Leaves

    Rekha Gadre

    2013-08-01

    Full Text Available Drought stress is one of the major abiotic constraint limiting plant growth and productivity world wide. The current study was undertaken with the aim to investigate the effect of water deficit imposed by PEG-6000, on chlorophyll metabolism in maize leaves to work out the mechanistic details. Leaf segments prepared from primary leaves of etiolated maize seedlings were treated with varying concentrations of polyethylene glycol-6000 (PEG-6000; w/v- 5%, 10%, 20%, 30% in continuous light of intensity 40 Wm-2 at 26±2 °C for 24 h in light chamber. The results demonstrate a concentration dependent decline in chlorophyll content with increasing concentration of polyethylene glycol-6000 (PEG-6000. Reduction in chlorophyll ‘a’ level was to a greater extent than the chlorophyll ‘b’. The RNA content decreased in a concentration dependent manner with PEG, however, proline content increased significantly. Relative water content decreased significantly with the supply of 30% PEG only. A substantial decrease in chlorophyll synthesis due to significant reduction in ALA content and ALAD activity, with no change in chlorophyllase activity with the supply of PEG suggests that water deficit affects chlorophyll formation rather than its degradation.

  13. Chlorophyll and carbohydrates in Arachis pintoi plants under influence of water regimes and nitrogen fertilization

    Rita Manuele Porto Sales

    2013-06-01

    Full Text Available In this experiment the chlorophyll and carbohydrate contents of Arachis pintoi were evaluated to verify if the presence of nitrogen in the soil could contribute to the effectiveness of the establishment of this legume. The design was completely randomized, in a 4 × 4 factorial arrangement, with four N rates (0, 40, 80 and 120 kg ha-1 and four irrigation levels (25, 50, 75 and 100% of field capacity, with four replications. The biochemical evaluations of chlorophylls a and b and total chlorophyll and total soluble sugars, sucrose and starch were performed. The highest contents of chlorophyll a and b and total chlorophyll in leaves were found at the dose of 120 kg ha-1. The water regime of 25% of field capacity was responsible for the lowest content of reducing sugars and total soluble sugars in leaves, stolons and roots. In the roots, the sucrose contents were higher in these conditions, which can be associated with a slight tolerance of the plant to water stress. The water deficiency was responsible for the decrease of reducing sugars and total N in the whole plant and positively influenced the levels of chlorophyll and sugars in the stolon, promoting growth, especially of shoots, at the beginning of establishment.

  14. Spatiotemporal Variation in Mangrove Chlorophyll Concentration Using Landsat 8

    Julio Pastor-Guzman

    2015-11-01

    Full Text Available There is a need to develop indicators of mangrove condition using remotely sensed data. However, remote estimation of leaf and canopy biochemical properties and vegetation condition remains challenging. In this paper, we (i tested the performance of selected hyperspectral and broad band indices to predict chlorophyll concentration (CC on mangrove leaves and (ii showed the potential of Landsat 8 for estimation of mangrove CC at the landscape level. Relative leaf CC and leaf spectral response were measured at 12 Elementary Sampling Units (ESU distributed along the northwest coast of the Yucatan Peninsula, Mexico. Linear regression models and coefficients of determination were computed to measure the association between CC and spectral response. At leaf level, the narrow band indices with the largest correlation with CC were Vogelmann indices and the MTCI (R2 > 0.5. Indices with spectral bands around the red edge (705–753 nm were more sensitive to mangrove leaf CC. At the ESU level Landsat 8 NDVI green, which uses the green band in its formulation explained most of the variation in CC (R2 > 0.8. Accuracy assessment between estimated CC and observed CC using the leave-one-out cross-validation (LOOCV method yielded a root mean squared error (RMSE = 15 mg·cm−2, and R2 = 0.703. CC maps showing the spatiotemporal variation of CC at landscape scale were created using the linear model. Our results indicate that Landsat 8 NDVI green can be employed to estimate CC in large mangrove areas where ground networks cannot be applied, and mapping techniques based on satellite data, are necessary. Furthermore, using upcoming technologies that will include two bands around the red edge such as Sentinel 2 will improve mangrove monitoring at higher spatial and temporal resolutions.

  15. Chlorophyll f distribution and dynamics in cyanobacterial beachrock biofilms.

    Trampe, Erik; Kühl, Michael

    2016-12-01

    Chlorophyll (Chl) f, the most far-red (720-740 nm) absorbing Chl species, was discovered in cyanobacterial isolates from stromatolites and subsequently in other habitats as well. However, the spatial distribution and temporal dynamics of Chl f in a natural habitat have so far not been documented. Here, we report the presence of Chl f in cyanobacterial beachrock biofilms. Hyperspectral imaging on cross-sections of beachrock from Heron Island (Great Barrier Reef, Australia), showed a strong and widely distributed signature of Chl f absorption in an endolithic layer below the dense cyanobacterial surface biofilm that could be localized to aggregates of Chroococcidiopsis-like unicellular cyanobacteria packed within a thick common sheath. High-pressure liquid chromatography-based pigment analyses showed in situ ratios of Chl f to Chl a of 5% in brown-pigmented zones of the beachrock, with lower ratios of ~0.5% in the black- and pink-pigmented biofilm zones. Enrichment experiments with black beachrock biofilm showed stimulated synthesis of Chl f and Chl d when grown under near-infrared radiation (NIR; 740 nm), with a Chl f to Chl a ratio increasing 4-fold to 2%, whereas the Chl d to Chl a ratio went from 0% to 0.8%. Enrichments grown under white light (400-700 nm) produced no detectable amounts of either Chl d or Chl f. Beachrock cyanobacteria thus exhibited characteristics of far-red light photoacclimation, enabling Chl f -containing cyanobacteria to thrive in optical niches deprived of visible light when sufficient NIR is prevalent. © 2016 Phycological Society of America.

  16. Mapping genes governing flower architecture and pollen development in a double mutant population of carrot

    Holger eBudahn

    2014-10-01

    Full Text Available A linkage map of carrot (Daucus carota L. was developed in order to study reproductive traits. The F2 mapping population derived from an initial cross between a yellow leaf (yel chlorophyll mutant and a compressed lamina (cola mutant with unique flower defects of the sporophytic parts of male and female organs. The genetic map has a total length of 781 cM and included 285 loci. The length of the nine linkage groups ranged between 65 cM and 145 cM. All linkage groups have been anchored to the reference map. The objective of this study was the generation of a well-saturated linkage map of D. carota. Mapping of the cola-locus associated with flower development and fertility was successfully demonstrated. Two MADS-box genes (DcMADS3, DcMADS5 with prominent roles in flowering and reproduction as well as three additional genes (DcAOX2a, DcAOX2b, DcCHS2 with further importance for male reproduction were assigned to different loci that did not co-segregate with the cola-locus.

  17. The research progress on plant mutant germplasm resources in China

    He Cexi; Ji Linzhen; Zhao Shirong

    1991-07-01

    Mutants induced by nuclear radiation or other mutagens are new artificial germplasm resources. Some mutants have been applied in plant breeding and great achievements have been reached. The status and progress on the collection, identification and utilization of mutants in China are introduced. A proposal for developing mutant germplasm resources with good agronomic characters is suggested

  18. Conceptualising the lack of health insurance coverage.

    Davis, J B

    2000-01-01

    This paper examines the lack of health insurance coverage in the US as a public policy issue. It first compares the problem of health insurance coverage to the problem of unemployment to show that in terms of the numbers of individuals affected lack of health insurance is a problem comparable in importance to the problem of unemployment. Secondly, the paper discusses the methodology involved in measuring health insurance coverage, and argues that the current method of estimation of the uninsured underestimates the extent that individuals go without health insurance. Third, the paper briefly introduces Amartya Sen's functioning and capabilities framework to suggest a way of representing the extent to which individuals are uninsured. Fourth, the paper sketches a means of operationalizing the Sen representation of the uninsured in terms of the disability-adjusted life year (DALY) measure.

  19. Laura: Soybean variety lacking Kunitz trypsin inhibitor

    Srebrić Mirjana

    2010-01-01

    Full Text Available Grain of conventional soybean varieties requires heat processing to break down trypsin inhibitor's activity before using as food or animal feed. At the same time, protein denaturation and other qualitative changes occur in soybean grain, especially if the temperature of heating is not controlled. Two types of trypsin inhibitor were found in soybean grain the Kunitz trypsin inhibitor and the Bowman-Birk inhibitor. Mature grain of soybean Laura is lacking Kunitz trypsin inhibitor. Grain yield of variety Laura is equal to high yielding varieties from the maturity group I, where it belongs. Lacking of Kunitz-trypsin inhibitor makes soybean grain suitable for direct feeding in adult non ruminant animals without previous thermal processing. Grain of variety Laura can be processed for a shorter period of time than conventional soybeans. This way we save energy, and preserve valuable nutritional composition of soybean grain, which is of interest in industrial processing.

  20. Seasonality in sub-surface chlorophyll maxima in the Arabian Sea: Detection by IRS-P4/OCM and implication of it to primary productivity

    Matondkar, S.G.P.; Parab, S.G.; Dwivedi, R.M.

    various seasons. During November at St. 1 surface chlorophyll a was 1.503 mgm-3and subsurface chlorophyll maxima was 12.692 mgm-3. Similarly, at St. 13 surface chlorophyll a was 0.584 mgm-3and surface chlorophyll maxima was 8.517 mgm-3. During upwelling...

  1. A thermo-sensitive purple leaf rice mutant--PLM12 and its genetical study

    Wu Guanting; Wang Xianyu; Jin Wei

    2001-01-01

    PLM12 was a thermo-sensitive purple leaf mutant selected from Indica rice variety Luqingzao 1 treated with pingyangmycin in combination with γ-rays, and for display of its mutant character, a relatively high temperature was required. Compared with its original parent, many major agronomic traits of PLM12 changed to varied extents. Based on spikelet cutting experiment, it was believed that significant decreases in number of filled grains per panicle, fertility, and 1000-grain weight in PLM12 resulted mainly from a great decline in photosynthetic capacity and serious lack of photosynthate in purple leaves. It was indicated by genetic analysis that expression of the mutant phenotype in PLM12 was conditioned by a single recessive major nuclear gene and modified by several minor genes

  2. Mighty Dwarfs: Arabidopsis autoimmune mutants and their usages in genetic dissection of plant immunity

    Rowan Wersch

    2016-11-01

    Full Text Available Plants lack the adaptive immune system possessed by mammals. Instead they rely on innate immunity to defend against pathogen attacks. Genomes of higher plants encode a large number of plant immune receptors belonging to different protein families, which are involved in the detection of pathogens and activation of downstream defense pathways. Plant immunity is tightly controlled to avoid activation of defense responses in the absence of pathogens, as failure to do so can lead to autoimmunity that compromises plant growth and development. Many autoimmune mutants have been reported, most of which are associated with dwarfism and often spontaneous cell death. In this review, we summarize previously reported Arabidopsis autoimmune mutants, categorizing them based on their functional groups. We also discuss how their obvious morphological phenotypes make them ideal tools for epistatic analysis and suppressor screens, and summarize genetic screens that have been carried out in various autoimmune mutant backgrounds.

  3. Male-like sexual behavior of female mouse lacking fucose mutarotase

    Lim Dae-sik

    2010-07-01

    Full Text Available Abstract Background Mutarotases are recently characterized family of enzymes that are involved in the anomeric conversions of monosaccharides. The mammalian fucose mutarotase (FucM was reported in cultured cells to facilitate fucose utilization and incorporation into protein by glycosylation. However, the role of this enzyme in animal has not been elucidated. Results We generated a mutant mouse specifically lacking the fucose mutarotase (FucM gene. The FucM knockout mice displayed an abnormal sexual receptivity with a drastic reduction in lordosis score, although the animals were fertile due to a rare and forced intromission by a typical male. We examined the anteroventral periventricular nucleus (AVPv of the preoptic region in brain and found that the mutant females showed a reduction in tyrosine hydoxylase positive neurons compared to that of a normal female. Furthermore, the mutant females exhibited a masculine behavior, such as mounting to a normal female partner as well as showing a preference to female urine. We found a reduction of fucosylated serum alpha-fetoprotein (AFP in a mutant embryo relative to that of a wild-type embryo. Conclusions The observation that FucM-/- female mouse exhibits a phenotypic similarity to a wild-type male in terms of its sexual behavior appears to be due to the neurodevelopmental changes in preoptic area of mutant brain resembling a wild-type male. Since the previous studies indicate that AFP plays a role in titrating estradiol that are required to consolidate sexual preference of female mice, we speculate that the reduced level of AFP in FucM-/- mouse, presumably resulting from the reduced fucosylation, is responsible for the male-like sexual behavior observed in the FucM knock-out mouse.

  4. Customer Acceptance Survey On Chrysanthemum Mutant Developed By Nuclear Malaysia

    Shakinah Salleh; Zaiton Ahmad; Affrida Hassan; Shuhaimi Shamsudin; Nurul Hidayah Mahmud; Salim Othman; Mohamed Najli Mohamed Yasin

    2014-01-01

    Chrysanthemum morifolium is an important temperate cut flower for Malaysian floriculture industry and the lack of new local-owned varieties has led to this mutation breeding research. The project was started in 2008 under bilateral cooperation between Nuclear Malaysia and JAEA (Japan Atomic Energy Agency). Through this project, 8 new varieties of chrysanthemum were successfully developed, in which 4 varieties were from red cultivar and another 4 from pink cultivar. A preliminary survey on public perception and acceptance of these mutants was conducted on 7 January 2014 at Agrotechnology and Biosciences Division, Malaysian Nuclear Agency. The main objective of this survey was to gather information from the public on overall appearance of these new varieties and their potential for commercialization. Approximately 60 participants were involved in this survey, which include staff of Nuclear Malaysia, university students, plant growers/collectors and hobbyists. (author)

  5. Bacterio-opsin mutants of Halobacterium halobium

    Betlach, Mary; Pfeifer, Felicitas; Friedman, James; Boyer, Herbert W.

    1983-01-01

    The bacterio-opsin (bop) gene of Halobacterium halobium R1 has been cloned with about 40 kilobases of flanking genomic sequence. The 40-kilobase segment is derived from the (G+C)-rich fraction of the chromosome and is not homologous to the major (pHH1) or minor endogenous covalently closed circular DNA species of H. halobium. A 5.1-kilobase Pst I fragment containing the bop gene was subcloned in pBR322 and a partial restriction map was determined. Defined restriction fragments of this clone were used as probes to analyze the defects associated with the bop gene in 12 bacterio-opsin mutants. Eleven out of 12 of the mutants examined had inserts ranging from 350 to 3,000 base pairs either in the bop gene or up to 1,400 base pairs upstream. The positions of the inserts were localized to four regions in the 5.1-kilobase genomic fragment: within the gene (one mutant), in a region that overlaps the 5′ end of the gene (seven mutants), and in two different upstream regions (three mutants). Two revertants of the mutant with the most distal insert had an additional insert in the same region. The polar effects of these inserts are discussed in terms of inactivation of a regulatory gene or disruption of part of a coordinately expressed operon. Given the defined nature of the bop mRNA—i.e., it has a 5′ leader sequence of three ribonucleotides—these observations indicate that the bop mRNA might be processed from a large mRNA transcript. Images PMID:16593291

  6. Recent developments and future directions in the monitoring of terrestrial sun-induced chlorophyll fluorescence from space

    Guanter, L.

    2017-12-01

    Sun-induced chlorophyll fluorescence (SIF) is an electromagnetic signal emitted by the chlorophyll-a of assimilating plants in the 650-850 nm spectral range. The SIF emission has a mechanistic link to photosynthesis and responds instantaneously to perturbations in environmental conditions such as light and water stress, which makes it a powerful proxy for plants' photosynthetic activity. Global measurements of SIF from space have been available since late 2011 from four different atmospheric satellite missions (chronologically, GOSAT, SCIAMACHY, GOME-2 and OCO-2). The potential of the derived SIF data sets to represent the photosynthetic activity of different ecosystems, including large crop belts worldwide, the Amazon rainforest and boreal evergreen forests has been demonstrated in the relatively short life-time of global SIF data. Despite the demonstrated potential of SIF data as a proxy for global terrestrial gross primary production, current observations are partly hampered by a coarse spatial resolution or the lack of spatial coverage. For this reason, great expectations are put on the upcoming TROPOMI instrument onboard the Copernicus' Sentinel 5-Precursor mission to be launched by mid-end of 2017. TROPOMI will provide daily global coverage with a spatial resolution between 3 and 7 km and continuous spectral coverage of the visible and near-infrared part of the spectrum. The recent selection of FLEX as the ESA Earth Explorer 8 to be launched around 2022 and several upcoming geostationary missions (TEMPO, Sentinel-4 and GeoCARB, covering Europe and the Americas) with potential for SIF retrievals complete an exciting near-future scenario for the monitoring of SIF from space. In this contribution, we will provide an overview of recent developments in the global monitoring of SIF and will introduce the near-future observational scenario with especial emphasis on TROPOMI and the geostationary missions to be launched in the coming years.

  7. Accidents in radiotherapy: Lack of quality assurance?

    Novotny, J.

    1997-01-01

    About 150 radiological accidents, involving more than 3000 patients with adverse effects, 15 patient's fatalities and about 5000 staff and public exposures have been collected and analysed. Out of 67 analysed accidents in external beam therapy 22% has been caused by wrong calculation of the exposure time or monitor units, 13% by inadequate review of patient's chart, 12% by mistakes in the anatomical area to be treated. The remaining 35% can be attributed to 17 different causes. The most common mistakes in brachytherapy were wrong activities of sources used for treatment (20%), inadequate procedures for placement of sources applicators (14%), mistakes in calculating the treatment time (12%), etc. The direct and contributing causes of radiological accidents have been deduced from each event, when it was possible and categorized into 9 categories: mistakes in procedures (30%), professional mistakes (17%), communication mistakes (15%), lack of training (8.5%), interpretation mistakes (7%), lack of supervision (6%), mistakes in judgement (6%), hardware failures (5%), software and other mistakes (5.5%). Three types of direct and contributing causes responsible for almost 62% of all accidents are directly connected to the quality assurance of treatment. The lessons learnt from the accidents are related to frequencies of direct and contributing factors and show that most of the accident are caused by lack, non-application of quality assurance (QA) procedures or by underestimating of QA procedures. The international system for collection of accidents and dissemination of lessons learnt from the different accidents, proposed by IAEA, can contribute to better practice in many radiotherapy departments. Most of the accidents could have been avoided, had a comprehensive QA programme been established and properly applied in all radiotherapy departments, whatever the size. (author)

  8. Characterization and protective property of Brucella abortus cydC and looP mutants.

    Truong, Quang Lam; Cho, Youngjae; Barate, Abhijit Kashinath; Kim, Suk; Hahn, Tae-Wook

    2014-11-01

    Brucella abortus readily multiplies in professional or nonprofessional phagocytes in vitro and is highly virulent in mice. Isogenic mutants of B. abortus biovar 1 strain IVKB9007 lacking the ATP/GDP-binding protein motif A (P-loop) (named looP; designated here the IVKB9007 looP::Tn5 mutant) and the ATP-binding/permease protein (cydC; designated here the IVKB9007 cydC::Tn5 mutant) were identified and characterized by transposon mutagenesis using the mini-Tn5Km2 transposon. Both mutants were found to be virtually incapable of intracellular replication in both murine macrophages (RAW264.7) and the HeLa cell line, and their virulence was significantly impaired in BALB/c mice. Respective complementation of the IVKB9007 looP::Tn5 and IVKB9007 cydC::Tn5 mutants restored their ability to survive in vitro and in vivo to a level comparable with that of the wild type. These findings indicate that the cydC and looP genes play important roles in the virulence of B. abortus. In addition, intraperitoneal immunization of mice with a dose of the live IVKB9007 looP::Tn5 and IVKB9007 cydC::Tn5 mutants provided a high degree of protection against challenge with pathogenic B. abortus strain 544. Both mutants should be evaluated further as a live attenuated vaccine against bovine brucellosis for their ability to stimulate a protective immune response. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Mutants with Enhanced Nitrogenase Activity in Hydroponic Azospirillum brasilense-Wheat Associations

    Pereg Gerk, Lily; Gilchrist, Kate; Kennedy, Ivan R.

    2000-01-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induced mutants were established. The results of this study show that the ability of Sp7 and Sp245 mutant strains to remain in a vegetative form improved their ability to express nitrogenase activity in association with wheat in a hydroponic system. Restoring the cyst formation and colonization pattern to the spontaneous mutant Sp7-S reduced nitrogenase activity rates in association with plants to that of the wild-type Sp7. Although Tn5-induced flcA mutants showed higher potentials for nitrogenase expression than Sp7, their potentials were lower than that of Sp7-S, indicating that other factors in this strain contribute to its exceptional nitrogenase activity rates on plants. The lack of lateral flagella is not one of these factors, as Sp7-PM23, a spontaneous mutant impaired in swarming and lateral-flagellum production but not in flocculation, showed wild-type nitrogenase activity and expression. The results also suggest factors of importance in evolving an effective symbiosis between Azospirillum and wheat, such as increasing the availability of microaerobic niches along the root, increased supply of carbon sources by the plant, and the retention of the bacterial cells in vegetative form for faster metabolism. PMID:10788397

  10. Why does Colombia lack agricultural commodity futures?

    Pablo Moreno-Alemay

    2015-11-01

    Full Text Available This article explores the reasons why futures contracts are not traded as an alternative to price hedging for agricultural goods in Colombia. Based on surveys, interviews and statistical analysis, this study identified that conceptual gaps in contract negotiation, lack of consensus in the agricultural sector regarding the use of financial mechanisms and the sector’s infrequent contact with Colombia’s financial institutions, are the main reasons why a futures contracts market has not emerged.

  11. Leishmania infantum HSP70-II null mutant as candidate vaccine against leishmaniasis: a preliminary evaluation

    Fresno Manuel

    2011-07-01

    Full Text Available Abstract Background Visceral leishmaniasis is the most severe form of leishmaniasis and no effective vaccine exists. The use of live attenuated vaccines is emerging as a promising vaccination strategy. Results In this study, we tested the ability of a Leishmania infantum deletion mutant, lacking both HSP70-II alleles (ΔHSP70-II, to provide protection against Leishmania infection in the L. major-BALB/c infection model. Administration of the mutant line by either intraperitoneal, intravenous or subcutaneous route invariably leads to the production of high levels of NO and the development in mice of type 1 immune responses, as determined by analysis of anti-Leishmania IgG subclasses. In addition, we have shown that ΔHSP70-II would be a safe live vaccine as immunodeficient SCID mice, and hamsters (Mesocricetus auratus, infected with mutant parasites did not develop any sign of pathology. Conclusions The results suggest that the ΔHSP70-II mutant is a promising and safe vaccine, but further studies in more appropriate animal models (hamsters and dogs are needed to appraise whether this attenuate mutant would be useful as vaccine against visceral leishmaniasis.

  12. The Drosophila Neurally Altered Carbohydrate Mutant Has a Defective Golgi GDP-fucose Transporter*

    Geisler, Christoph; Kotu, Varshika; Sharrow, Mary; Rendić, Dubravko; Pöltl, Gerald; Tiemeyer, Michael; Wilson, Iain B. H.; Jarvis, Donald L.

    2012-01-01

    Studying genetic disorders in model organisms can provide insights into heritable human diseases. The Drosophila neurally altered carbohydrate (nac) mutant is deficient for neural expression of the HRP epitope, which consists of N-glycans with core α1,3-linked fucose residues. Here, we show that a conserved serine residue in the Golgi GDP-fucose transporter (GFR) is substituted by leucine in nac1 flies, which abolishes GDP-fucose transport in vivo and in vitro. This loss of function is due to a biochemical defect, not to destabilization or mistargeting of the mutant GFR protein. Mass spectrometry and HPLC analysis showed that nac1 mutants lack not only core α1,3-linked, but also core α1,6-linked fucose residues on their N-glycans. Thus, the nac1 Gfr mutation produces a previously unrecognized general defect in N-glycan core fucosylation. Transgenic expression of a wild-type Gfr gene restored the HRP epitope in neural tissues, directly demonstrating that the Gfr mutation is solely responsible for the neural HRP epitope deficiency in the nac1 mutant. These results validate the Drosophila nac1 mutant as a model for the human congenital disorder of glycosylation, CDG-IIc (also known as LAD-II), which is also the result of a GFR deficiency. PMID:22745127

  13. Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Ambystoma mexicanum.

    Woodcock, M Ryan; Vaughn-Wolfe, Jennifer; Elias, Alexandra; Kump, D Kevin; Kendall, Katharina Denise; Timoshevskaya, Nataliya; Timoshevskiy, Vladimir; Perry, Dustin W; Smith, Jeramiah J; Spiewak, Jessica E; Parichy, David M; Voss, S Randal

    2017-01-31

    The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning-candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyr a ) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyr a has a 142 bp deletion and similar engineered alleles recapitulated the albino phenotype. Finally, we show that historical introgression of tyr a significantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl.

  14. Thermosensitive mutant of Bacillus subtilis deficient in uracil and cell division

    Nagai, K; Some, H; Tamura, G

    1976-01-01

    Thermonsensitive division mutants were derived from Bacillus subtilis Marburg 168 thy trp/sub 2/ by means of membrane filtration after nitrosoguanidine mutagenesis. Among them, ts42 requiring uracil for normal growth at 48/sup 0/C was investigated. In the absence of uracil, the mutant cells grew normally at 37/sup 0/C and stopped dividing after temperature shift to 48/sup 0/C resulting in filaments of two to four times length of normal rods. The total cell number after the temperature shift increased two to three fold in 90 min and remained constant thereafter. The viable count after the temperature shift to 48/sup 0/C, increased 1.5 to 2 fold in initial 60 min and then decreased exponentially. A rapid restoration of colony forming ability was shown when the mutant cells were shifted back to the permissive temperature after 120 to 180 min of incubation at 48/sup 0/C or when uracil was introduced to the culture at 48/sup 0/C. This recovery of viability was partly observed even in the presence of chloramphenicol. The synthesis of RNA of this mutant was shown to decline 20 min after the temperature shift to 48/sup 0/C whereas the syntheses of DNA and protein proceeded for more than 80 min at that temperature. No newly isolated uracil requiring mutants formed filaments in the medium lacking uracil or showed growth pattern like ts42.

  15. Measuring solar induced chlorophyll fluorescence (SIF) in the Amazon rainforest

    Kornfeld, A.; Stutz, J.; Berry, J. A.

    2016-12-01

    Measurement of solar induced chlorophyll fluorescence (SIF) has, in our hands, been fraught with missteps and puzzling problems. Here we describe lessons we have learned and the resulting novel system recently installed in the Amazon rainforest near Manaus, Brazil. The system is designed to measure light from 740 - 780 nm, enabling us to compare SIF computed from Fraunhofer lines in an optically transparent band of the atmosphere (745 - 759 nm) with SIF computed using the telluric O2A band (760 - 770 nm). Fraunhofer line analysis requires high optical resolution (better than 0.2 nm) to detect the relatively narrow lines, but we discovered that fiber-optic diffraction-grating spectrometers are sensitive to very small inhomogeneities in the lighting. Errors resulting from this autocorrelated but random noise were similar in magnitude to the SIF signal itself. Optical diffusers reduce this problem, leading to our final design: a sealed cylinder, dubbed Rotaprism, in which a rotatable prism selects whether light from upward- or downward-looking windows enters an axially-placed optical fiber. Cosine-correcting opal glass covering the windows not only solves the noise issue but also makes the measurements correspond to photon flux. Rotaprism also maximizes the amount of light reaching the spectrometer - maximizing the signal:noise ratio - by avoiding the need for lossy optical switches and fiber splitters. Rotaprism is driven by a pneumatic actuator that is controlled by electronic valves attached to a pressurized N2 source. The gas exhausts into the temperature-controlled spectrometer enclosure to help purge the optics. Finally, custom software provides fault-tolerant control and data acquisition, ensuring that measurements continue with little or no intervention at the remote field site despite unreliable power. Analysis of initial data demonstrates the advantage of Fraunhofer line SIF analysis: due to the atmosphere transparency in this band, the results are more

  16. Chlorophyll fluorescence response to water and nitrogen deficit

    Cendrero Mateo, Maria del Pilar

    The increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO2) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO2 exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF? ; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a

  17. Chlorophyll-a retrieval in the Philippine waters

    Perez, G. J. P.; Leonardo, E. M.; Felix, M. J.

    2017-12-01

    Satellite-based monitoring of chlorophyll-a (Chl-a) concentration has been widely used for estimating plankton biomass, detecting harmful algal blooms, predicting pelagic fish abundance, and water quality assessment. Chl-a concentrations at 1 km spatial resolution can be retrieved from MODIS onboard Aqua and Terra satellites. However, with this resolution, MODIS has scarce Chl-a retrieval in coastal and inland waters, which are relevant for archipelagic countries such as the Philippines. These gaps on Chl-a retrieval can be filled by sensors with higher spatial resolution, such as the OLI of Landsat 8. In this study, assessment of Chl-a concentration derived from MODIS/Aqua and OLI/Landsat 8 imageries across the open, coastal and inland waters of the Philippines was done. Validation activities were conducted at eight different sites around the Philippines for the period October 2016 to April 2017. Water samples filtered on the field were processed in the laboratory for Chl-a extraction. In situ remote sensing reflectance was derived from radiometric measurements and ancillary information, such as bathymetry and turbidity, were also measured. Correlation between in situ and satellite-derived Chl-a concentration using the blue-green ratio yielded relatively high R2 values of 0.51 to 0.90. This is despite an observed overestimation for both MODIS and OLI-derived values, especially in turbid and coastal waters. The overestimation of Chl-a may be attributed to inaccuracies in i) remote sensing reflectance (Rrs) retrieval and/or ii) empirical model used in calculating Chl-a concentration. However, a good 1:1 correspondence between the satellite and in situ maximum Rrs band ratio was established. This implies that the overestimation is largely due to the inaccuracies from the default coefficients used in the empirical model. New coefficients were then derived from the correlation analysis of both in situ-measured Chl-a concentration and maximum Rrs band ratio. This

  18. Photosynthesis and chlorophyll fluorescence reaction to different shade stresses of weak light sensitive maize

    Wang, J.; Li, F.; Shi, Z.; Huang, H.; Jia, S.

    2017-01-01

    A split-plot experimental study was conducted to evaluate the effect of different shade stresses on photosynthesis and chlorophyll fluorescence of maize leaves.The experiment was designed on the south farm of Special Corn Institute, Shenyang Agricultural University, China.Data was collected from the day maize tasseled (Jul. 21) to the beginning of grouting (Aug.12 ) under 18%, 28%, 38%, 60%, and 75% shade stress to determine indexes such as photosynthesis and chlorophyll fluorescence after 15 days of shade treatment. Pairs of near-isogenic lines (NILs) of Shennong 98A (a barren stalk inbred line) and Shennong 98B (an un-barren stalk inbred line) were used as experimental materials to further reveal photosynthetic mechanisms of weak light sensitive maize when exposed to weak light conditions. Thus, a foundation was established for high density-resistant (shade resistant) corn breeding,while identifying weak light sensitive varieties. After shading treatment, chlorophyll a and total chlorophyll content of both varieties increased, chlorophyll b content first increased, followed by a decrease, while the net photosynthetic rate and stomatal conductance showed a gradually decreasing trend. The changing trends of photochemical quenching coefficient(qp) and effective quantum yield of PSII photochemistry (FPSII)were similar, FPSII and qP increased significantly as shading stress increased from 18% to 38%;however, FPSII and qP declined significantly under 60% and 75% shading stresses. The changing trend of NPQ was opposite to FPSII and qP. A comparison of both inbred lines showed that photosynthesis and chlorophyll fluorescence characteristics of Shennong 98B were superior to Shennong 98A. This study revealed the relationships between weak light sensitive lines and shade intensities by comparing differences in photosynthesis and chlorophyll fluorescence parameters. (author)

  19. Long-term dynamics of chlorophyll concentration in the ocean surface layer (by space data)

    Shevyrnogov, A.; Vysotskaya, G.

    To preserve the biosphere and to use it efficiently, it is necessary to gain a deep insight into the dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. These investigations are, however, very labor-consuming, because of the difficulties related to the accessibility of the water surface and its large size. In this work long-term changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years from 1979 to 1986 and the SeaWiFS data from 1997 to 2004. It has been shown that the average chlorophyll concentration calculated in all investigated areas varies moderately. However, when analyzing spatially local trends, the areas have been detected that have significant rise and fall of chlorophyll concentrations. Some interesting features of the long-term dynamics of chlorophyll concentration have been found. The opposite directions of long-term trends (essential increase or decrease) cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings, etc.). The measured chlorophyll concentration results from the balance between production and destruction processes. Which process dominates is determined by various hydrophysical, hydrobiological, and climatic processes, leading to sharp rises or falls of the concentration. It is important to estimate the scale of the areas in which this or that process dominates. Therefore, the study addresses not only the dynamics of the mean value but also the dynamics of the areas in which the dominance of certain factors has led to a sharp fall or rise in chlorophyll concentration. Thus, the obtained results can be used to estimate long-term changes in the ocean biota.

  20. Microdroplet fusion mass spectrometry: accelerated kinetics of acid-induced chlorophyll demetallation.

    Lee, Jae Kyoo; Nam, Hong Gil; Zare, Richard N

    2017-01-01

    Kinetics of acid-induced chlorophyll demetallation was recorded in microdroplets by fusing a stream of microdroplets containing 40 µM chlorophyll a or b dissolved in methanol with a stream of aqueous microdroplets containing 35 mM hydrochloric acid (pH = 1·46). The kinetics of the demetallation of chlorophyll in the fused microdroplets (14 ± 6 µm diameter; 84 ± 18 m s-1 velocity) was recorded by controlling the traveling distance of the fused microdroplets between the fusion region and the inlet of a mass spectrometer. The rate of acid-induced chlorophyll demetallation was about 960 ± 120 times faster in the charged microdroplets compared with that reported in bulk solution. If no voltage was applied to the sprayed microdroplets, then the acceleration factor was about 580 ± 90, suggesting that the applied voltage is not a major factor determining the acceleration. Chlorophyll a was more rapidly demetallated than chlorophyll b by a factor of ~26 in bulk solution and ~5 in charged microdroplets. The demetallation kinetics was second order in the H+ concentration, but the acceleration factor of microdroplets compared with bulk solution appeared to be unchanged in going from pH = 1·3 to 7·0. The water:methanol ratio of the fused microdroplets was varied from 7:3 to 3:7 causing an increase in the reaction rate of chlorophyll a demetallation by 20%. This observation demonstrates that the solvent composition, which has different evaporation rates, does not significantly affect the acceleration. We believe that a major portion of the acceleration can be attributed to confinement effects involving surface reactions rather than either to evaporation of solvents or to the introduction of charges to the microdroplets.