共查询到20条相似文献,搜索用时 15 毫秒
1.
Carole Colin Catherine Leblanc Gurvan Michel Elsa Wagner Emmanuelle Leize-Wagner Alain Van Dorsselaer Philippe Potin 《Journal of biological inorganic chemistry》2005,10(2):156-166
The brown alga Laminaria digitata features a distinct vanadium-dependent iodoperoxidase (vIPO) activity, which has been purified to electrophoretic homogeneity. Steady-state analyses at pH 6.2 are reported for vIPO (K m I– =2.5 mM; k cat I– =462 s–1) and for the previously characterised vanadium-dependent bromoperoxidase in L. digitata (K m I– =18.1 mM; k cat I– =38 s–1). Although the vIPO enzyme specifically oxidises iodide, competition experiments with halides indicate that bromide is a competitive inhibitor with respect to the fixation of iodide. A full-length complementary ANA (cDNA) was cloned and shown to be actively transcribed in L. digitata and to encode the vIPO enzyme. Mass spectrometry analyses of tryptic digests of vIPO indicated the presence of at least two very similar proteins, in agreement with Southern analyses showing that vIPOs are encoded by a multigenic family in L. digitata. Phylogenetic analyses indicated that vIPO shares a close common ancestor with brown algal vanadium-dependent bromoperoxidases. Based on a three-dimensional structure model of the vIPO active site and on comparisons with those of other vanadium-dependent haloperoxidases, we propose a hypothesis to explain the evolution of strict specificity for iodide in L. digitata
vIPO.The nucleotide sequence reported in this paper has been submitted to the EBI Data Bank with accession no. AJ619804. 相似文献
2.
Microchemical imaging of iodine distribution in the brown alga Laminaria digitata suggests a new mechanism for its accumulation 总被引:2,自引:0,他引:2
Elodie Françoise Verhaeghe Aurélien Fraysse Jean-Luc Guerquin-Kern Ting-Di Wu Guillaume Devès Charles Mioskowski Catherine Leblanc Richard Ortega Yves Ambroise Philippe Potin 《Journal of biological inorganic chemistry》2008,13(2):257-269
Brown algal kelp species are the most efficient iodine accumulators among all living systems, with an average content of 1.0%
of dry weight in Laminaria digitata. The iodine distributions in stipe and blade sections from L. digitata were investigated at tissue and subcellular levels. The quantitative tissue mapping of iodine and other trace elements (Cl,
K, Ca, Fe, Zn, As and Br) was provided by the proton microprobe with spatial resolutions down to 2 μm. Chemical imaging at
a subcellular resolution (below 100 nm) was performed using the secondary ion mass spectrometry microprobe. Sets of samples
were prepared by both chemical fixation and cryofixation procedures. The latter prevented the diffusion and the leaching of
labile inorganic iodine species, which were estimated at around 95% of the total content by neutron activation analysis. The
distribution of iodine clearly shows a huge, decreasing gradient from the meristoderm to the medulla. The contents of iodine
reach very high levels in the more external cell layers, up to 191 ± 5 mg g−1 of dry weight in stipe sections. The peripheral tissue is consequently the main storage compartment of iodine. At the subcellular
level, iodine is mainly stored in the apoplasm and not in an intracellular compartment as previously proposed. This unexpected
distribution may provide an abundant and accessible source of labile iodine species which can be easily remobilized for potential
chemical defense and antioxidative activities. According to these imaging data, we proposed new hypotheses for the mechanism
of iodine storage in L. digitata tissues.
In memory of Dr. Charles Mioskowski, “Miko,” who died on 2 June 2007. 相似文献
3.
The regeneration of meristematic tissues from sporophytes of Laminaria digitata was studied by protoplast and tissue culture. Sequential treatment of explants in sterile seawater with 1% Betadine for 5 min,
1% commercial bleach for 1–2 min and 2% antibiotic treatment supplemented with 1 μM GeO2 overnight enabled viable explants as high as 55%. Different morphogenetic responses were observed from tissue culture on
media supplemented with plant growth regulators alone or in combination, mainly filamentous calluses up to 50% according to
the media. Dark green compact calluses were observed on two combinations: 4 μM Pi + 2 μM N-(2-chloro-4-pyridyl)-N’-phenylurea
(CPPU) and 0.04 μM Pi + 0.44 μM 6-benzylaminopurine. Thalloid-like structures comparable to adventitious buds were regenerated
on medium supplemented with 4 μM Pi + 0.45 μM zeatin but at low frequency suggesting a strong genotypic effect. Friable calluses
were developed from protoplasts in enriched medium with polyamines and containing 0.40 μM CPPU + 0.45 μM 2,4-dichlorophenoxyacetic
acid. In order to produce protoplasts, a one-step enzymatic protocol was developed and yields reached 22 × 106 protoplasts per gram of fresh weight. 相似文献
4.
5.
Blade discs of vegetative thalli of Laminaria digitata (Huds.) Lamour. from Helgoland (North Sea) cut at 5–15 cm distance from the blade/stipe transition, formed sorus in the laboratory
after 7–12weeks, 5 months earlier than whole fronds in the field. Sorus formation occurred in a broad range of daylength regimes
or temperatures, at 8–16 h light pe rday and 6–12 °C. No sorus was developed during three months by meristematic blade discs cut from the lowermost 3 cm portion of the blade,
nor from whole thalli cultured in parallel to isolated blade discs. These findings point to the possible existence of sporulation
inhibitors produced by the laminarian meristem.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Growth of young sporophytes of the brown algae Laminaria digitata, L. saccharina and L. solidungula from Spitsbergen were measured in the laboratory after being exposed for 21 days to either photosynthetically active radiation
(PAR=P) or to full light spectrum (PAR + UV-A + UV-B=PAB) using of cutoff glass filters. The plants were grown at 8±2°C and
16 h light : 8 h dark cycles with 6 h additional ultraviolet radiation (UVR) exposure in the middle of the light period. Growth
was measured every 10 min using growth chambers with online video measuring technique. Tissue morphology and absorption spectra
were measured in untreated young sporophytes while chlorophyll (Chl) a content and DNA damage were measured in treated thalli at the end of the experiment. In all species, growth rates were significantly
higher in sporophytes exposed to P alone compared to sporophytes exposed to PAB. Tissue DNA damage is dependent on thallus
thickness and absorption spectra characteristics of pigments and UV-absorbing compounds. In sporophytes exposed to UVR, energy
demands for repair of DNA damage and synthesis of UV-absorbing compounds for protection effectively diverts photosynthate
at the expense of growth. Photosynthetic pigment was not significantly different between treatments suggesting a capacity
for acclimation to moderate UVR fluence. The general growth pattern in sporophytes exposed to P alone showed an increasing
growth rate from the onset of light (0500–0900 hours) to a peak at the middle of the light phase (0900–1500 hours), a decline
towards the end of the light phase (1500–2100 hours) and a minimum “low” growth in the dark (2100–0500 hours) relative to
growth during the entire light phase. Under PAB, different growth patterns were observed such as growth compensation at night
in L. digitata, delayed growth recovery in L. saccharina and minimal but continuous growth in L. solidungula. Growth as an integrative parameter of all physiological processes showed that the effect of UVR is correlated to the depth
distribution of these species. 相似文献
7.
Preparation of protoplasts from Laminaria japonica using native and recombinant abalone alginate lyases 总被引:1,自引:0,他引:1
Laminaria japonica protoplasts were released with high yields using the abalone alginate lyase HdAly in combination with a cellulase and chelating
agents. Addition of EDTA at concentrations higher than 10 mM to Laminaria thalli which had been preincubated with HdAly and Cellulase Onozuka, dramatically improved the yield of protoplasts. EDTA
was far more effective than EGTA, indicating that chelating divalent metal ions such as Mg2+ and Sr2+ in addition to Ca2+ is a key factor for high-yield production of Laminaria protoplasts. Protoplasts had a mean diameter of 27 μm, suggesting that most protoplasts were derived from cortical cells
rather than epidermal layer cells. Recombinant HdAly (rHdAly) was produced from a cDNA clone in the Sf9 insect cell expression
system. rHdAly had substantially the same enzymatic properties and protoplast-producing ability as did native HdAly. The optimal
conditions for high yield production of protoplasts from Laminaria using native and recombinant HdAlys were investigated. 相似文献
8.
9.
Characterisation of complementary DNAs from the expressed sequence tag analysis of life cycle stages of Laminaria digitata (Phaeophyceae) 总被引:1,自引:0,他引:1
Laminariales (Phaeophyceae, Heterokonta) are characterised by a heteromorphic digenetic life cycle with a filamentous, microscopic gametophyte and a highly evolved, macroscopic sporophyte. With the ultimate goal of comparing gene expression in each life cycle stage, complementary DNA libraries were constructed from sporophytes and gametophytes of Laminaria digitata. A set of ca. 500 expressed sequence tags (EST) was generated from each life history phase, by single-run partial sequencing of randomly picked cDNA clones. Comparison of the EST deduced amino acid sequences with database protein sequences assigned a putative identity for 39% of the 412 gametophyte clones and 48% of the 493 sporophyte clones sequenced thus far. These data represent more than 152 different proteins now probably identified in L. digitata. Several of those newly identified proteins are of interest to our understanding of the molecular physiology of kelps, for example their carbon-concentrating mechanisms, cell wall biosynthesis and halogen metabolism. EST analysis also confirmed that genes with long 3-UTRs are widespread in Laminariales and the study of 5-UTRs allowed the identification of a Kozak consensus sequence, c(A/C)A(A/C)CAUGGc(G/T). Several potential developmentally regulated differences in gene expression are discussed. 相似文献
10.
11.
12.
The polyphenols present in brown seaweed tissue may seriously affect aerobic microbial degradation, particularly the alginate
present. Laminaria hyperborea stipes, harvested at 59 °N off the Norwegian coast in autumn, were degraded at different levels
of polyphenols in aerated batch reactors at 35 °C and pH 7. This was achieved by manipulating the relative amounts of peripheral
tissue, by removing or adding the mechanically peeled outer phenolic layer, using standardized inocula already adapted to
L. hyperborea degradation. The degradation of organic matter was clearly depressed by increasing the amount of peripheral
tissue. Alginate lyase activity was also negatively correlated to the amount of peripheral tissue loaded, presumably due to
the release of reactive polyphenols. The total digestion rates of alginate were reduced by more than a factor of two at enhanced
amounts of peripheral tissue. The guluronic content of extracted Na-alginate increased during the degradation, despite the
presence of significant amounts of guluronate specific alginate lyase activity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
A high-yield technique is described for the elaboration of single cell detritus (SCD) from Laminaria saccharina, based on the sequential action of C1H, enzymes (endoglucanases and cellulases) and 2 bacteria showing a high degree of cellobiotic, proteolytic, and alginolytic activity (CECT 5255 and CECT 5256). Over 85% of dried particles of L. saccharina were transformed into a suspension of free cell and bacterial and detrital particles after 24 hours of bacterial activity with this technique. These particles were less than 20 m in diameter, constituting a suitable diet for bivalve mollusks. After 72 hours 99% of the total particulate volume consisted of particles less than 20 m in diameter. Tests of hatchery diets for the seed of clam Ruditapes decussatus revealed increases of 54% and 68% for live weight and length, respectively, when SCD from L. saccharina was used as the sole dietary component compared with a live phytoplankton diet. However, SCD from L. saccharina is not a suitable food for the larvae of R. decussatus. 相似文献
14.
Jing-Yu Li Yukio Agatsuma Takeshi Nagai Yoichi Sato Kazuya Taniguchi 《Journal of applied phycology》2009,21(2):215-224
The kelps Laminaria longissima and L. diabolica, belonging to the groups of L. angustata and L. japonica, respectively, differ greatly in their morphological characteristics although their geographical distributions overlap widely
along the eastern coast of Hokkaido. To clarify the interaction between the morphological and physiological characteristics
of the two species, and their link with environmental variables, hatchery-raised young sporophytes of L. longissima and L. diabolica collected from Hokkaido were cultivated simultaneously under similar conditions in Matsushima Bay, Miyagi, from January to
July 2004. Seasonal morphological characteristics, gross photosynthetic rate, nutrient uptake rates, and resource contents
were examined. The blade lengths of L. longissima and L. diabolica reached a maximum of 329.9 cm and 256.7 cm, respectively, in April to May, and decreased to 284.4 cm and 68.6 cm, respectively,
in July. The total elongation length of L. longissima (412.5 cm) was similar to that of L. diabolica (373.8 cm). However, the total erosion length of L. longissima (145.9 cm) was approximately half that of L. diabolica (302.9 cm). The gross photosynthetic rate and uptake rates of NH4-N, NO3-N, and PO4-P of the two species were similar. However, the carbon, nitrogen, and phosphorus contents were transferred and stored in
the whole blade tissues in the case of L. longissima, but in the meristem of L. diabolica from May to June. These results suggest that morphological differences are a response to different resource storage patterns.
The storage patterns of L. longissima and L. diabolica are likely to be genetically fixed characteristics, which have evolved in adaptation to the specific habitat environments
of the groups of L. angustata and L. japonica. The low water temperature and rich nutrients provided by the Oyashio Current are conducive to storage of resources in the
whole blade tissues and a large surface area retained for photosynthesis and nutrient uptake in the L. angustata group. Conversely, high temperature and poor nutrients, or large fluctuations in these parameters, provided by the Tsushima
Warm Current are more conducive to intensive storage of resources in the meristem for maturation and further growth in the
L. japonica group. L. diabolica retains the storage pattern of the L. japonica group but grows in regions affected by the Oyashio Current, allowing it to become the widest distributed Laminaria species. 相似文献
15.
Localization of antigens homologous to excretory-secretory proteins in developing embryos ofSetaria digitata has been carried out by indirect fluorescent antibody test, [14C] labelling studies and Western blotting. Indirect fluorescent antibody test showed binding of excretory-secretory antibodies
at perivitelline space. The fluorescent antibody binding was almost absent at small morulae stage and increasing in intensity
in the successive developmental stages with maximum at coiled microfilaria stage. Hatched microfilaria did not show the presence
of antigens by immunofluorescence. Immuno-complex of excretory-secretory antiserum against “amniotic fluid” collected from
developing embryos ofSetaria digitata labelled with [14C] amino acids showed highest radioactivity at coiled and tadpole stages and differed significantly from small morulae, big
morulae and hatched microfilaria. Immunoblot analysis of amniotic fluid showed two proteins, 16.5 and 11 kDa, to be highly
antigenic. The antigenic protein (11 kDa) content as seen by immuno blotting increased during embryogenesis and decreased
at the stage of hatching. 相似文献
16.
活性氧在海带抗褐藻酸降解菌感染中的作用 总被引:3,自引:0,他引:3
海带是我国大型经济海藻养殖的主要对象 ,养殖历史长 ,用途广泛。海带人工育苗是发展我国海带养殖事业的一个重要环节。海带病烂 (烂柄病 ) ,尤其在育苗期 ,将造成很大的经济损失。研究指出 ,海带的病烂与褐藻酸降解菌的大量繁殖有关[1- 3 ] 。褐藻酸降解菌是海带藻体上主要附生细菌 ,正常情况下并不引起病烂 ,但若养殖环境恶化 ,如过于密植、损伤、温度过高等 ,使海带的抵抗力下降 ,细菌易于侵入并大量繁殖而导致病害。本文以褐藻酸降解菌为病原细菌 ,研究海带活性氧的产生及其在抵抗褐藻酸降解菌感染过程中所起的作用 ,以期为揭示海带活性… 相似文献
17.
Setaria digitata, a filarial parasite of cattle possesses certain unique characteristics like cyanide insensitivity, and lack of cytochromes.
In the present study, we have shown that the parasite has an incomplete tricarboxylic acid cycle with the absence of activities
of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase and succinyl-CoA synthase. However the parasite showed the existence
of glyoxylate cycle and phosphoenolpyruvate-succinate pathway. The widely used antifilarial drug diethylcarbamazine caused
general inhibition of all enzymes of phosphoenolpyruvate-succinate pathway and glyoxylate cycle except that of fumarase and
isocitrate lyase. The results may pave the way for new targets for chemotherapy in the control of filarial parasites. 相似文献
18.
The effects of exogenous abscisic acid (ABA;10–7–10–5 M), a knownplantgrowth regulator, on reproduction and growth were investigated by culturingdiscs from sporophytes of Laminaria japonica Areschoug.ABAplays a role in triggering sorus formation, and it was found that sorusformation of discs was fastest in 10–5 M ABA. Theapplication of 10–5 M ABA to culturing discs alsosuppressed the expansion of surface area. ABA contents in sorus and vegetativeparts of the sporophyte were determined by bioassay. The mean ABA content insorus parts obtained from sporophytes was 0.222 ± 0.053g equivalent-ABA g wet weight–1, which wasabout five times higher than the content found in vegetative parts (0.048± 0.009 g equivalent-ABA g wetweight–1). Taken together these results suggest that sorusdevelopment requires an elevated level of ABA and is associated with decreasingvegetative growth and that the ABA level of the sporophyte may play a crucialrole in reproduction. 相似文献
19.
20.
32P was applied to a Laminaria digitata thallus and the pattern of 32P phosphorylated compounds was studied, as a function of time, in the different tissues involved in translocation, i.e. source, pathway and sinks. The results showed that, 3 hours after absorption by the uptake region (lamina), the bulk of the radioactivity was incorporated into organic compounds (70 to 80% of total 32P taken up), hexose monophosphates being the heaviest labelled. Further change in that region was marked by an accumulation of 32P in the inorganic pool (65 to 70% after 13 days). Conversely, the 32P pattern in the medulla of the stipe, which initially showed a similar pattern to the uptake region, did not vary during translocation. The pattern of 32P distribution into sinks (growing stipe peripheral tissue or hapteron) leads to accumulation of the radioactive element in inorganic and acid-insoluble fractions. These results are discussed in terms of comparative distribution of 32P in the different parts of the thallus and suggest that phosphate moves as Pi in that alga.Abbreviations TCA
trichloroacetic acid
- Po
organic phosphate
- Po sol
acid-soluble organic phosphate fraction
- Po insol
acidinsoluble organic phosphate fraction
- Pi
morganic phosphate fraction
- P lip
lipidic phosphate
- Np
protein nitrogen
- ATP
adenosine triphosphate
- ADP
adenosine diphosphate
- PEP
phosphoenolpyruvic acid
- PGA
phosphoglyceric acid
- G-1-P
glucose-1-phosphate
- G-6-P
glucose-6-phosphate
- UDPG
uridine diphosphoglucose 相似文献