共查询到20条相似文献,搜索用时 31 毫秒
1.
A role for the peripheral (B800-850) light-harvesting complex in vesicularization of the Rhodobacter sphaeroides intracytoplasmic membrane (ICM), suggested from studies in mutant strains lacking one or more of the pigment-protein complexes,
was examined further in the wild-type strain NCIB 8253 grown at high (∼1000 W m–2), moderate (∼300 W m–2), and low (∼100 W m–2) light intensities. The resulting ICM vesicles (chromatophores) had B800-850 levels related inversely to irradiance and banded
in rate-zone sedimentation at ∼1.10, 1.09, and 1.07 g ml–1, respectively. Equilibrium centrifugation on iso-osmotic gradients indicated that this distinct sedimentation behavior resulted
solely from differences in hydrodynamic radii. These size differences were confirmed by gel-exclusion chromatography and in
electron micrographs of thin-sectioned cells. A pulse-chase study of ICM growth following a tenfold reduction in light intensity
showed a relatively slow equilibration of membrane proteins during adaptation, and that new protein was incorporated largely
into additional ICM formed at the lowered illumination level, giving rise to chromatophores of reduced size and elevated B800-850
content. These results provide further evidence for a model in which the B800-850 complex both drives development of vesicular
ICM in Rba. sphaeroides and determines the size of resulting vesicles.
Received: 12 October 1995 / Accepted: 21 December 1995 相似文献
2.
Bin Zhao Yi Liang He Jue Huang Shauna Taylor Joseph Hughes 《Journal of industrial microbiology & biotechnology》2010,37(6):609-616
Providencia rettgeri strain YL was found to be efficient in heterotrophic nitrogen removal under aerobic conditions. Maximum removal of NH4
+–N occurred under the conditions of pH 7 and supplemented with glucose as the carbon source. Inorganic ions such as Mg2+, Mn2+, and Zn2+ largely influenced the growth and nitrogen removal efficiency. A quantitative detection of nitrogen gas by gas chromatography
was conducted to evaluate the nitrogen removal by strain YL. From the nitrogen balance during heterotrophic growth with 180 mg/l
of NH4
+–N, 44.5% of NH4
+–N was in the form of N2 and 49.7% was found in biomass, with only a trace amount of either nitrite or nitrate. The utilization of nitrite and nitrate
during the ammonium removal process demonstrated that the nitrogen removal pathway by strain YL was heterotrophic nitrification-aerobic
denitrification. A further enzyme assay of nitrate reductase and nitrite reductase activity under the aerobic condition confirmed
this nitrogen removal pathway. 相似文献
3.
A new bacterial strain isolated from soil consumed nitric oxide (NO) under oxic conditions by oxidation to nitrate. Phenotypic
and phylogenetic characterization of the new strain PS88 showed that it represents a previously unknown species of the genus
Pseudomonas, closely related to Pseudomonas fluorescens and Pseudomonas putida. The heterotrophic, obligately aerobic strain PS88 was not able to denitrify or nitrify; however, strain PS88 oxidized NO
to nitrate. NO was not reduced to nitrous oxide (N2O). Nitrogen dioxide (NO2) and nitrite (NO2
–) as possible intermediates of NO oxidation to nitrate (NO3
–) could not be detected. NO oxidation was inhibited under anoxic conditions and by high osmolarity, but not by nitrite. NO
oxidation activity was inhibited by addition of formaldehyde, HgCl2, and antimycin, and by autoclaving or disintegrating the cells, indicating that the process was enzyme-mediated. However,
the mechanism remains unclear. A stepwise oxidation at a metalloenzyme and a radical mechanism are discussed. NO oxidation
in strain PS88 seems to be a detoxification or a co-oxidation mechanism, rather than an energy-yielding process.
Received: 15 November 1995 / Accepted: 24 February 1996 相似文献
4.
An agarolytic bacterium, designated as strain M5cT, was isolated from sea sand in Jeju Island, Korea. This isolate was Gram-negative, positive for catalase and oxidase, rod
and motile by means of monotrichous flagella. Strain M5cT has translucent or dark ivory colonies, forms a dent on an agar plate under colonies, and grows in the presence of 1–12%
(w/v) NaCl and at 10–37°C. This isolate hydrolyzes agar, alginic acid, carboxymethyl (CM)-cellulose and starch. Phylogenetic
analysis based on 16S rRNA gene sequences showed that strain M5cT can be considered as a species within the genus Gilvimarinus, being most closely related to Gilvimarinus chinensis QM42T, with a 16S rRNA gene sequence similarity of 95.6%. The major cellular fatty acids were C16:1ω7c and/or iso-C15:0 2OH (33.5%),
C16:0 (26.5%) and C18:1ω7c (14.1%). The DNA G+C content was 53.8 mol%. Based on these polyphasic data, strain M5cT should be classified as a novel species, for which the name Gilvimarinus agarilyticus sp. nov. is proposed. The type strain for the novel species is M5cT (= KCTC 23325T = NCAIM B 02425T). 相似文献
5.
Nadia Khelifi Emna Ben Romdhane Abdeljabbar Hedi Anne Postec Marie-Laure Fardeau Moktar Hamdi Jean-Luc Tholozan Bernard Ollivier Agnès Hirschler-Réa 《Extremophiles : life under extreme conditions》2010,14(3):297-304
A novel thermophilic anaerobic and microaerophilic bacterium (optimal growth in the presence of 5–10% O2), strain Nad S1T was isolated from the terrestrial hot spring of Hammam Sidi Jdidi, Nabeul, Tunisia. Cells were motile rods having a Gram-positive
cell wall structure. Strain Nad S1T grew optimally at 55°C (range 37–70°C). Optimum pH for growth was 6.5–7.0. It was halotolerant growing with NaCl up to 7%
(optimum concentration 1.5–3.0%). It grew chemoorganotrophically on various carbohydrates, organic-acids and amino-acids as
energy sources, or chemolithotrophically on H2 using nitrate, as terminal electron acceptor. Beside oxygen (under microaerobic conditions) and nitrate, nitrite was also
used. Nitrate was completely reduced to N2. No fermentation occurred. The genomic DNA G + C content was 41.8 mol%. Based on 16S rRNA gene sequence analysis, strain
Nad S1T belongs to the Bacillaceae family within the class ‘Bacilli’. Because of its phylogenetic and phenotypic characteristics, we propose this isolate to be assigned as a novel genus and
a novel species within the domain Bacteria, Microaerobacter geothermalis gen. nov., sp. nov. The type strain is Nad S1T (=DSM 22679T =JCM 16213T). 相似文献
6.
Flores A Nisola GM Cho E Gwon EM Kim H Lee C Park S Chung WJ 《Bioprocess and biosystems engineering》2007,30(3):197-205
The performance of enriched sludge augmented with the B21 strain of Alcaligenes defragrans was compared with that of enriched sludge, as well as with pure Alcaligenes defragrans B21, in the context of a sulfur-oxidizing denitrification (SOD) process. In synthetic wastewater treatment containing 100–1,000 mg
NO3−-N/L, the single strain-seeded system exhibited superior performance, featuring higher efficiency and a shorter startup period,
provided nitrate loading rate was less than 0.2 kg NO3−-N/m3 per day. At nitrate loading rate of more than 0.5 kg NO3−-N/m3 per day, the bioaugmented sludge system showed higher resistance to shock loading than two other systems. However, no advantage
of the bioaugmented system over the enriched sludge system without B21 strain was observed in overall efficiency of denitrification.
Both the bioaugmented sludge and enriched sludge systems obtained stable denitrification performance of more than 80% at nitrate
loading rate of up to 2 kg NO3−-N/m3 per day. 相似文献
7.
Effi Eisenmann Joachim Beuerle Klaus Sulger Peter M. H. Kroneck Wolfram Schumacher 《Archives of microbiology》1995,164(3):180-185
Sulfurospirillum deleyianum grew in batch culture under anoxic conditions with sulfide (up to 5 mM) as electron donor, nitrate as electron acceptor,
and acetate as carbon source. Nitrate was reduced to ammonia via nitrite, a quantitatively liberated intermediate. Four moles
of sulfide were oxidized to elemental sulfur per mole nitrate converted to ammonia. The molar growth yield per mole sulfide
consumed, Ym, was 1.5 ± 0.2 g mol–1 for the reduction of nitrate to ammonia. By this type of metabolism, S. deleyianum connected the biogeochemical cycles of sulfur and nitrogen. The sulfur reductase activity in S. deleyianum was inducible, as the activity depended on the presence of sulfide or elemental sulfur during cultivation with nitrate or
fumarate as electron acceptor. Hydrogenase activity was always high, indicating that the enzyme is constitutively expressed.
The ammonia-forming nitrite reductase was an inducible enzyme, expressed when cells were cultivated with nitrate, nitrite,
or elemental sulfur, but repressed after cultivation with fumarate.
Received: 13 March 1995 / Accepted: 29 May 1995 相似文献
8.
A. A. Filimonenkov R. A. Zvyagilskaya T. V. Tikhonova V. O. Popov 《Biochemistry. Biokhimii?a》2010,75(6):744-751
A novel nitrate reductase (NR) was isolated from cell extract of the haloalkaliphilic bacterium Thioalkalivibrio nitratireducens strain ALEN 2 and characterized. This enzyme is a classical nitrate reductase containing molybdopterin cofactor in the active
site and at least one iron-sulfur cluster per subunit. Mass spectrometric analysis showed high homology of NR with the catalytic
subunit NarG of the membrane nitrate reductase from the moderately halophilic bacterium Halomonas halodenitrificans. In solution, NR exists as a monomer with a molecular weight of 130–140 kDa and as a homotetramer of about 600 kDa. The specific
nitrate reductase activity of NR is 12 μmol/min per mg protein, the maximal values being observed within the neutral range
of pH. Like other membrane nitrate reductases, NR reduces chlorate and is inhibited by azide and cyanide. It exhibits a higher
thermal stability than most mesophilic enzymes. 相似文献
9.
F. Neese R. Kappl J. Hüttermann W. G. Zumft P. M. H. Kroneck 《Journal of biological inorganic chemistry》1998,3(1):53-67
CW ENDOR (X-band) spectra for the purple mixed-valence [Cu(1.5+)...Cu(1.5+)], S = 1/2, CuA site in nitrous oxide reductase were obtained after insertion of 65Cu or both 65Cu and 15N-histidine. The 14N/15N isotopic substitution allowed for an unambiguous deconvolution of proton and nitrogen hyperfine couplings in the spectra.
A single nitrogen coupling with a value of 12.9 ± 0.4 MHz for 14N was detected. Its anisotropy was characteristic for imidazole bound to copper. A spin density of 3–5% was estimated for
the nitrogen donors to CuA, indicating that the ground state is 2B3u. Proton hyperfine structure was detected from four Cβ protons of coordinating cysteine residues. Their isotropic and anisotropic parts were deconvoluted by spectral simulation.
From the anisotropic couplings a spin density of 16–24% was estimated for each of the cysteine thiolate donors of CuA. The [NHisCu(RS)2CuNHis]+ core structure of CuA in nitrous oxide reductase from Pseudomonas stutzeri is predicted to be similar to the crystallographically determined CuA* structure (Wilmanns M, Lappalainen P, Kelly M, Sauer-Eriksson E, Saraste M (1995) Proc Natl Acad Sci USA 92 : 11955–11959),
but distinct from the CuA structure of Paracoccus denitrificans cytochrome c oxidase (Iwata S, Ostermeier C, Ludwig B, Michel H (1995) Nature 376 : 660–669). The angular dependence of the isotropic couplings
as a function of the electronic ground state was calculated by the INDO/S method. The Mulliken atomic-spin populations calculated
by a gradient-corrected density functional method and the semiempirical INDO/S method were compared with experimentally derived
spin populations, and good agreement between theory and experiment was found for both calculations. The ground state of CuA is best represented by the resonance structures of the form [CuIS–S–CuII↔ CuIS•S–CuI↔ CuIS–S•CuI↔ CuIIS–S–CuI]. It is proposed that the Cu 4s,p as well as sulfur 3d orbitals play a role in the stabilization of this novel type of cluster.
Received: 17 September 1997 / Accepted: 28 October 1997 相似文献
10.
A. I. Saralov B. B. Kuznetsov E. M. Reutskikh R. V. Baslerov A. N. Panteleeva N. E. Suzina 《Microbiology》2012,81(5):582-588
A halophilic nonpigmented rod-shaped (0.8–1.0 × 2.0–2.5 μm), gram-negative bacterium with a single polar flagellum (strain RS91) was isolated from acidic brines of flotation enrichment of potassium minerals (Silvinit Co., Solikamsk, Russia). The strain grew in the media with 2 to 25% NaCl (optimum at 10–12%), 20–45°C (optimum at 37°C), and pH 5.5–8.5 (optimum 6.5–7.5). It was an aerobe or facultative anaerobe incapable of fermentation. The strain was characterized by the absence of growth on glucose, fructose, and citrate, extensive aerobic growth on n-hexadecane and in the mineral medium with H2 + O2 + CO2 in the gas phase, anaerobic nitrate reduction with acetate or hydrogen (under H2 + CO2 + N2), and variable fatty acid composition. The DNA G+C content was 68.2 mol %. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that while strain RS91 was most closely related to Arhodomonas aquaeolei HA-1T (98.3%) and Nitrococcus mobilis (98.1%), it was only remotely related to the halophilic phototroph Halorhodospira halophila (90.6%). Based on the combination of its phenotypic and genotypic characteristics, the organism was classified as a new species of the genus Arhodomonas, family Ectothiorhodospiraceae with the proposed name Arhodomonas recens sp. nov. The type strain is RS91T (= IEGM 796T = VKPM B-11280T). 相似文献
11.
Chlorate and nitrate reduction in the phototrophic bacteriaRhodobacter capsulatus andRhodobacter sphaeroides 总被引:1,自引:0,他引:1
Chlorate or trimethylamine-N-oxide (TMAO) added to phototrophic cultures ofRhodobacter sphaeroides DSM 158 increased both the growth rate and the growth yield although this stimulation was not observed in the presence of tungstate. This strain, exhibited basal activities of nitrate, chlorate, and TMAO reductases independently of the presence of these substrates in the culture medium, and nitrate reductase (NR) activity was competitively inhibited by chlorate. Phototrophic growth ofRhodobacter capsulatus B10, a strain devoid of NR activity, was inhibited only by 100 mM chlorate. However, growth of the nitrate-assimilatingR. capsulatus strains E1F1 and AD2 was sensitive to 10mm chlorate, and their NR activities were not inhibited by chlorate. Both NR and chlorate reductase (CR) activities of strain E1F1 were induced in the presence of nitrate or chlorate respectively, whereas strain AD2 showed basal levels of these activities in the absence of the substrates. A basal TMAO reductase (TR) activity was also observed when these strains ofR. capsulatus were cultured in the absence of this electron acceptor. These results suggest that chlorate and TMAO can be used as ancillary oxidants byRhodobacter strains and that a single enzyme could be responsible for nitrate and chlorate reduction inR. sphaeroides DSM 158, whereas these reactions are catalyzed by two different enzymes inR. capsulatus E1F1 and AD2. 相似文献
12.
Earthworm secondary production and N flux in agroecosystems: a comparison of two approaches 总被引:1,自引:0,他引:1
Production was estimated for Aporrectodea spp. and Lumbricus spp. populations in corn agroecosystems with a 5-year history of manure or inorganic fertilizer applications during 1994–1995
and 1995–1996. Earthworm biomass and production were greater in manure than inorganic fertilizer plots, although biomass and
production declined by about 50% between 1994–1995 and 1995–1996 due to unfavorable climatic conditions. Production was highest
during the spring and autumn when soil temperatures were between 4 and 22°C. Production was higher in Lumbricus spp. than Aporrectodea spp. populations due to greater Lumbricus spp. biomass. Aporrectodea spp. production was 3.47–16.14 g ash-free dry weight (AFDW) m–2 year–1, while Lumbricus spp. production was 6.09–18.11 g AFDW m–2 year–1, depending on the fertilizer treatment and the method used to estimate production. However, production estimates from the
instantaneous growth rate method were within 27% of the values calculated using the size-frequency method. Nitrogen flux through
earthworms was used to estimate efficiency quotients. Net production efficiency (P/A) ranged from 0.64 to 0.76, assimilation efficiency (A/C) ranged from 0.1 to 0.3, and gross production efficiency (P/C) ranged from 0.06 to 0.22. Annual N flux through earthworm populations was higher in manure than inorganic fertilizer plots,
and ranged from 2.95 to 5.47 g N m–2 year–1 in 1994–1995 and 1.76 to 2.92 g N m–2 year–1 in 1995–1996. The N flux through earthworms represented an amount equivalent to 16–30% of crop N uptake during 1994–1995
and 11–18% of crop N uptake during 1995–1996. We concluded that the effects of earthworms on N cycling in corn agroecosystems
were substantial, and that N flux through earthworms was influenced significantly by fertilizer amendments.
Received: 20 September 1999 / Accepted: 24 March 2000 相似文献
13.
Nonibala Khumanthem Mayashree B. Syiem Arvind K. Singh Amar Nath Rai 《Indian journal of microbiology》2007,47(4):345-352
A Mastigocladus species was isolated from the hot spring of Jakrem (Meghalaya) India. Uptake and utilization of nitrate, nitrite, ammonium
and amino acids (glutamine, asparagine, arginine, alanine) were studied in this cyanobacterium grown at different temperatures
(25°C, 45°C). There was 2–3 fold increase in the heterocyst formation and nitrogenase activity in N-free medium at higher
temperature (45°C). Growth and uptake and assimilation of various nitrogen sources were also 2–3 fold higher at 45°C indicating
that it is a thermophile. The extent of induction and repression of nitrate uptake by NO3
− and NH4
+, respectively, differed from that of nitrite. It appeared that Mastigocladus had two independent nitrate/nitrite transport systems. Nitrate reductase and nitrite reductase activitiy was not NO3
−-inducible and ammonium or amino acids caused only partial repression. Presence of various amino acids in the media partially
repressed glutamine synthetase activity. Ammonium (methylammonium) and amino acid uptake showed a biphasic pattern, was energy-dependent
and the induction of uptake required de novo protein synthesis. Ammonium transport was substrate (NH4
+)-repressible, while the amino acid uptake was substrate inducible. When grown at 25°C, the cyanobacterium formed maximum
akinetes that remained viable upto 5 years under dry conditions. 相似文献
14.
Anna L. Ballard Alastair G. McEwan David J. Richardson J. Baz Jackson Stuart J. Ferguson 《Archives of microbiology》1990,154(3):301-303
Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO
trimethylamine-N-oxide 相似文献
15.
Cristina Correia Stéphane Besson Carlos D. Brondino Pablo J. González Guy Fauque Jorge Lampreia Isabel Moura José J. G. Moura 《Journal of biological inorganic chemistry》2008,13(8):1321-1333
Membrane-bound nitrate reductase from Marinobacter hydrocarbonoclasticus 617 can be solubilized in either of two ways that will ultimately determine the presence or absence of the small (Ι) subunit.
The enzyme complex (NarGHI) is composed of three subunits with molecular masses of 130, 65, and 20 kDa. This enzyme contains
approximately 14 Fe, 0.8 Mo, and 1.3 molybdopterin guanine dinucleotides per enzyme molecule. Curiously, one heme b and 0.4 heme c per enzyme molecule have been detected. These hemes were potentiometrically characterized by optical spectroscopy at pH 7.6
and two noninteracting species were identified with respective midpoint potentials at E
m = +197 mV (heme c) and −4.5 mV (heme b). Variable-temperature (4–120 K) X-band electron paramagnetic resonance (EPR) studies performed on both as-isolated and dithionite-reduced
nitrate reductase showed, respectively, an EPR signal characteristic of a [3Fe–4S]+ cluster and overlapping signals associated with at least three types of [4Fe–4S]+ centers. EPR of the as-isolated enzyme shows two distinct pH-dependent Mo(V) signals with hyperfine coupling to a solvent-exchangeable
proton. These signals, called “low-pH” and “high-pH,” changed to a pH-independent Mo(V) signal upon nitrate or nitrite addition.
Nitrate addition to dithionite-reduced samples at pH 6 and 7.6 yields some of the EPR signals described above and a new rhombic
signal that has no hyperfine structure. The relationship between the distinct EPR-active Mo(V) species and their plausible
structures is discussed on the basis of the structural information available to date for closely related membrane-bound nitrate
reductases.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Matthias Hofmann 《Journal of biological inorganic chemistry》2009,14(7):1023-1035
[Mo(SSCH3)(S2C2(CH3)2)2]
x
complexes with charges x between −3 and +3 were investigated by density functional theory computations as minimal nitrate reductase active-site models.
The strongly reduced species (x = −2, −3) exist preferentially as pentacoordinate sulfo complexes separated from a thiolate anion. The oxidized extremes
(x > 0) clearly prefer hexacoordinate complexes with an η2-MeSS ligand. Among the neutral and especially for the singly negatively charged species structures with η2-MeSS and η1-MeSS ligands are energetically close to the sulfo methyl sulfide complex without SS bonding. For x = −1 the three isomers lie in a 1.5 kcal mol−1 energy range. Putative mechanistic pathways for nitrate reduction from the literature were investigated computationally:
(1) reduction at a pentacoordinate sulfo complex, (2) reduction at the ligand, and (3) reduction at the molybdenum center
with an R–S–S ligand. All three pathways could be traced at least for some overall charges but no definite conclusion can
be drawn about the mechanism. Complexes with larger dithiolato ligands were also computed in order to model the tricyclic
metallopterin framework more accurately: the first heterocyclus (5,6-dihydro-2H-pyran) stabilizes the nitrate complex and the molybdenum oxo product complex by approximately 10 kcal mol−1 and also reduces the activation barrier (by approximately 5 kcal mol−1). The effect of the second (1,2,3,4-tetrahydropyrazin) and third heterocyclus (2-amino-3H-pyrimidin-4-one) on the relative energies is relatively small. For bigger models derived from an experimental protein structure,
nitrate reduction at a persulfo molybdenum(IV) complex fragment (mechanism 3) is clearly favored over the oxidation of a molybdenum-bound
sulfur atom (mechanism 2). Mechanism 1 could not be investigated for the big models but seems the least favorable on the basis
of the results from smaller models. 相似文献
17.
An ionizing- and UV-radiation-resistant bacterial strain, designated ZLM-202T, was isolated from an arid soil sample collected from Xinjiang Province, north-west China. The soil sample was irradiated
before serial dilution plating was performed using twofold-diluted marine agar. Phylogenetic analysis based on 16S rRNA gene
sequences indicated that strain ZLM-202T was a member of the genus Deinococcus, exhibiting sequence similarities of 86.3–92.2% to the type strains of recognized Deinococcus species. Strain-ZLM-202T was strictly aerobic and showed optimum growth at 30–37°C and pH 7.0. The major respiratory menaquinone was MK-8. The major
fatty acids were 16:1 ω7c, 16: 0, 15: 1 ω6c, 15: 0 iso and 16: 1 ω5c. L-ornithine was detected in its peptidoglycan. The polar lipid profile consisted mainly of various unknown phosphoglycolipids,
aminophospholipids, glycolipids and phospholipids. The DNA G + C content was 65.5 mol. %. The strain was shown to be extremely
resistant to gamma radiation (>10 kGy) and UV light (>600 J m−2). On the basis of the phylogenetic, chemotaxonomic and phenotypic data, strain ZLM-202T represents a novel species of the genus Deinococcus, for which the name Deinococcus soli sp. nov. is proposed. The type strain is ZLM-202T (=CCTCC AB 208223T=KCTC 13419T). 相似文献
18.
Gang-Guk Choi Byung-Hyuk Kim Chi-Yong Ahn Hee-Mock Oh 《Journal of applied phycology》2011,23(6):1031-1037
The influence of nitrogen (N) deficiency on the cell growth and intracellular lipid production of the alga Botryococcus braunii UTEX 572 was investigated. Biomass concentration and lipid content of B. braunii cultivated in modified Chu-13 medium containing 0.04, 0.37, and 3.66 mM nitrate were 0.23–0.38 g L−1 and 36–63% of dry cell weight, respectively. The specific growth rate of B. braunii reached a constant of 0.185 day−1 during cultivation with an initial nitrate feed of 3.66 mM. The maximum lipid content of B. braunii was 63% with 0.04 mM nitrate. However, the maximum lipid productivity of 0.019 g L−1 day−1 was achieved with 0.37 mM nitrate. The level of oleic acid, an important component of biodiesel, was higher at 86% of the
total fatty acids under N-limited conditions (0.04 mM nitrate) compared to 69% under N-sufficient conditions (3.66 mM nitrate).
Furthermore, expression of the stearoyl-ACP desaturase gene (sad) encoding a stearoyl-ACP desaturase involved in the synthesis of oleic acid was 2.6-fold higher under N-limited conditions
than under N-sufficient conditions. 相似文献
19.
An aerobic, non-motile, catalase-positive, Gram-stain positive actinomycete designated YIM 63233T was isolated from the surface-sterilized leaves of Artemisia annua L. and characterized using a polyphasic taxonomic approach. Optimal growth occurred at 20–28°C, pH 6.0–7.0 and in the presence
of 0–3% (w/v) NaCl. 16S rRNA gene sequence-based phylogenetic analysis showed that strain YIM 63233T clustered with species of the genus Pseudonocardia, displaying ≥1.2% sequence divergence with recognized species of this genus (from 98.8 to 94.0%). Relatively low levels of
DNA–DNA relatedness were found between strain YIM 63233T and Pseudonocardia petroleophila IMSNU 22072T, which supported the classification of strain YIM 63233T within a novel species of the genus Pseudonocardia. The G + C content of genomic DNA was 72.0 mol%. Strain YIM 63233T possessed chemotaxonomic markers that were consistent with classification in the genus Pseudonocardia, i.e. the predominant fatty acids were iso-C16:0 (32.27%), C16:0 10-methyl (8.73%) and C17:1ω8c (8.30%), whilst the predominant
menaquinone was MK-8(H4). The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. The major cell wall sugars were glucose, arabinose, galactose, mannose and rhamnose. The results of
physiological and biochemical tests and DNA–DNA hybridization allowed the phenotypic and genotypic differentiation of strain
YIM 63233T from its closest phylogenetic neighbours. Therefore, the new isolate YIM 63233T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia serianimatus sp. nov. is proposed. The type strain is YIM 63233T (=DSM 45302T = CCTCC AA 208079T). 相似文献
20.
N. I. Mikshis O. M. Kudryavtseva D. V. Shulepov A. Yu. Goncharova M. F. Bolotnikova L. V. Novikova Yu. A. Popov V. V. Kutyrev 《Applied Biochemistry and Microbiology》2011,47(7):667-673
An asporogenic recombinant strain Bacillus anthracis 55ΔTPA-1(Spo−) producing anthrax protective antigen (PA) was obtained. The strain contains structural gene pag as a part of a hybrid replicon pUB110PA-1 and lacks determinants encoding the synthesis of main factors of anthrax pathogenicity.
The level of PA production by asporogenic genetically engineered strain is approximately 80 μg/ml that is 4–5 times more than
the values determined for vaccine strains B. anthracis STI-1 and B. anthracis 55. The strain preserves asporogenicity and ability to replicate the hybrid plasmid after in vitro passages. Biologically
active PA was isolated from the constructed strain B. anthracis 55ΔTPA-1(Spo−). Double immunization of rabbits with 50 μg of the purified recombinant product provides their 100% protection from infection
with 50 LD50 of a highly virulent anthrax strain. 相似文献