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1.
Clare Annabel Bowen-O’Connor John Hubstenberger Cynthia Killough Dawn Marie VanLeeuwen Rolston St. Hilaire 《In vitro cellular & developmental biology. Plant》2007,43(1):40-50
Bigtooth maple (Acer grandidentatum) is a promising ornamental tree that is not widely used in managed landscapes. Tissue culture has not been used successfully
to propagate this taxon. We cultured single- and double-node explants from greenhouse-grown, 2-y old seedlings of bigtooth
maples, which are indigenous to New Mexico, Texas, and Utah, on Murashige–Skoog (MS), Linsmaier–Skoog (LS), Driver–Kuniyuki
Walnut (DKW), and Woody Plant (WPM) tissue culture media. Media affected shoot proliferation (P = 0.0242) but the zone of explant origin (P = 0.7594) did not. After four 30-d subcultures, explants on DKW media and WPM media produced 3.6 and 3.5 shoots per explant,
respectively. Sprouting rates were highest on DKW, making DKW the best overall media for shoot proliferation. Double-node
microshoots were rooted in vitro on DKW containing indole acetic acid (IAA). Microshoots represented six genotypes from three locations within Texas and New
Mexico. Rooting percentage increased up to 15% as IAA concentration increased (P = 0.0040). There was 100% survival of rooted microshoots in vented Phytatrays containing one perlite: one peat moss (v/v). We conclude that DKW can be used to proliferate microshoots, and IAA induces rooting in microshoots of bigtooth maple. 相似文献
2.
Genome sequence analysis of Xanthomonas
oryzae pv. oryzae has revealed a cluster of 12 ORFs that are closely related to the gum gene cluster of Xanthomonas campestris pv. campestris. The gum gene cluster of X. oryzae encodes proteins involved in xanthan production; however, there is little experimental evidence supporting this. In this
study, biochemical analyses of xanthan produced by a defined set of X. oryzae
gum mutant strains allowed us to preliminarily assign functions to most of the gum gene products: biosynthesis of the pentasaccharide repeating unit for GumD, GumM, GumH, GumK, and GumI, xanthan polymerization
and transport for GumB, GumC, GumE, and GumJ, and modification of the pentasaccharide repeating unit for GumF, GumG, and GumL.
In addition, we found that the exopolysaccharides are essential but not specific for the virulence of X. oryzae.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Sang-Yoon Kim and Jeong-Gu Kim contributed equally to this work. 相似文献
3.
Valsartan orodispersible tablets have been developed at 40-mg dose, with the intention of facilitating administration to patients
experiencing problems with swallowing and hopefully, improving its poor oral bioavailability. Work started with selecting
drug compatible excipients depending on differential scanning calorimetric analysis. A 33 full factorial design was adopted for the optimization of the tablets prepared by freeze-drying technique. The effects of
the filler type, the binder type, and the binder concentration were studied. The different tablet formulas were characterized
for their physical properties, weight variation, disintegration time, surface properties, wetting properties, and in vitro dissolution. Amongst the prepared 27 tablet formulas, formula number 6 (consisting of 4:6 valsartan:mannitol and 2% pectin)
was selected to be tested in vivo. Oral bioavailability of two 40 mg valsartan orodispersible tablets was compared to the conventional commercial tablets after
administration of a single dose to four healthy volunteers. Valsartan was monitored in plasma by high-performance liquid chromatography.
The apparent rate of absorption of valsartan from the prepared tablets (C
max = 2.879 μg/ml, t
max = 1.08 h) was significantly higher than that of the conventional tablets (C
max = 1.471 μg/ml, t
max = 2.17 h), P ≤ 0.05. The relative bioavailability calculated as the ratio of mean total area under the plasma concentration–time curve
for the orodispersible tablets relative to the conventional ones was 135%. The results of the in vivo study revealed that valsartan orodispersible tablets would be advantageous with regards to improved patient compliance, rapid
onset of action, and increase in bioavailability. 相似文献
4.
Wang LW Xu BG Wang JY Su ZZ Lin FC Zhang CL Kubicek CP 《Applied microbiology and biotechnology》2012,93(3):1231-1239
Through bioassay-guided fractionation, the EtOAc extract of a culture broth of the endophytic fungus Phoma species ZJWCF006 in Arisaema erubescens afforded a new α-tetralone derivative, (3S)-3,6,7-trihydroxy-α-tetralone (1), together with cercosporamide (2), β-sitosterol (3), and trichodermin (4). The structures of compounds were established on the basis of spectroscopic analyses. Compounds 1, 2, and 3 were obtained from Phoma species for the first time. Additionally, the compounds were subjected to bioactivity assays, including antimicrobial activity,
against four plant pathogenic fungi (Fusarium oxysporium, Rhizoctonia solani, Colletotrichum gloeosporioides, and Magnaporthe oryzae) and two plant pathogenic bacteria (Xanthomonas campestris and Xanthomonas oryzae), as well as in vitro antitumor activities against HT-29, SMMC-772, MCF-7, HL-60, MGC80-3, and P388 cell lines. Compound
1 showed growth inhibition against F. oxysporium and R. solani with EC50 values of 413.22 and 48.5 μg/mL, respectively. Additionally, compound 1 showed no cytotoxicity, whereas compound 2 exhibited cytotoxic activity against the six tumor cell lines tested, with IC50 values of 9.3 ± 2.8, 27.87 ± 1.78, 48.79 ± 2.56, 37.57 ± 1.65, 27.83 ± 0.48, and 30.37 ± 0.28 μM, respectively. We conclude
that endophytic Phoma are promising sources of natural bioactive and novel metabolites. 相似文献
5.
Four oligosaccharides (penta-, hexa-, hepta- and octa-saccharide) derived from Paris polyphylla var. yunnanensis have been synthesized efficiently using a convergent glycosylation strategy. The tobacco (Nicotiana tabacum L.) growth bioactivities of the synthesized oligosaccharides were examined, using tissue-cultured seedlings grown on solid
MS medium. After 2 or 3 weeks, all four oligosaccharides had stimulated tobacco seedling growth at 1.0 ppm and the pentasaccharide
showed the most significant stimulus effects. Further experiments showed that the effects of pentasaccharide on tobacco growth
had an obvious concentration-dependent relationship in the range of 0.1–1.0 ppm. This stimulus effect showed some decrease
when the pentasaccharide concentration was higher than 1.0 ppm. At 1.0 ppm, pentasaccharide had the most significant effects,
which caused a 520% fresh weight increase of tobacco. The bioactivity of these synthesized oligosaccharides suggested that
they may be good prospects for the application in the control of plant growth and development. 相似文献
6.
Hai-Nan Su Bin-Bin Xie Xiu-Lan Chen Jin-Xia Wang Xi-Ying Zhang Bai-Cheng Zhou Yu-Zhong Zhang 《Journal of applied phycology》2010,22(1):65-70
Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple
and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding
hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed
by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude
phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0).
In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A
650/A
280 of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g−1 wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from
5.6 to 4.0. The absorbance ratio A
650/A
280 of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g−1 wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE. 相似文献
7.
Symptoms of fairy rings caused by Lepista sordida have been reported on Zoysiagrass (Zoysia spp.) turf maintained at fairway height (2 cm), but not on bentgrass (Agrostis spp.) maintained at putting green height (0.5 cm). The mycelia of this fungus inhabit primarily the upper 0–2 cm layer of
the soil extending into the thatch. To compare conditions for the mycelial growth in Z. matrella turf to those in A. palustris turf, we examined the effects of nutrients, temperature, water potential, and pH in the field as well as in the laboratory.
Greater growth of the mycelia was observed in medium that included hot water extracts from soil of the 0–1 cm zone in Z. matrella turf compared to that from A. palustris. The upper soil layer in Z. matrella turf contained more organic matter from clippings than that in A. palustris. The temperature and water potential of the 0–2 cm soil zone in Z. matrella turf were also more favorable for the mycelial growth. The soil pH values of this zone in Z. matrella turf were less favorable compared to A. palustris but within the range for accelerating mycelial growth.
Part of this study was presented orally at the 46th meeting of the Mycological Society of Japan in 2002 相似文献
8.
To screen stimulators from Chinese medicinal insects for mycelial growth and polysaccharides production of Ganoderma lucidum, G. lucidum was inoculated into the media with and without supplementation of medicinal insect extracts. The ethyl acetate extract of
Eupolyphaga sinensis at 55 mg l−1 lead to significant increase in both biomass and intracellular polysaccharides (IPS) concentration from 8.53 ± 0.41 to 14.16 ± 0.43
and 1.28 ± 0.09 to 2.13 ± 0.11 g l−1, respectively. In addition, the ethyl acetate extract of Catharsius molossus at 55 mg l−1 significantly enhanced extracellular polysaccharides (EPS) production; the EPS yield increased from 350.9 ± 14.1 to 475.1 ± 15.3 mg
l−1. There were no new components in the two types of polysaccharides obtained by the addition of the insect extracts. 相似文献
9.
Lima FL de Carvalho MA Apolônio AC Bemquerer MP Santoro MM Oliveira JS Alviano CS Farias Lde M 《Journal of industrial microbiology & biotechnology》2008,35(2):103-110
Aggregatibacter (Actinobacillus) actinomycetemcomitans P7–20 strain isolated from a periodontally diseased patient has produced a bacteriocin (named as actinomycetemcomitin) that is
active against Peptostreptococcus anaerobius ATCC 27337. Actinomycetemcomitin was produced during exponential and stationary growth phases, and its amount decreased until
it disappeared during the decline growth phase. It was purified by ammonium sulphate precipitation (30–60% saturation), and
further by FPLC (mono-Q ionic exchange and Phenyl Superose hydrophobic interaction) and HPLC (C-18 reversed-phase). This bacteriocin
loses its activity after incubation at a pH below 7.0 or above 8.0, following heating for 30 min at 45°C, and after treatment
with proteolytic enzymes such as trypsin, α-chymotrypsin, and papain. Actinomycetemcomitin has a molecular mass of 20.3 KDa
and it represents a new bacteriocin from A. actinomycetemcomitans. 相似文献
10.
Maofu Li Kaikai Zhu Songling Bai Zhi Liu Tianzhong Li 《Molecular breeding : new strategies in plant improvement》2011,28(2):171-180
Apple (Malus domestica Borkh.) possesses gametophytic self-incompatibility (GSI) which is controlled by S-RNase in the pistil as well as a pollen S-determinant that has not been well characterized. The identification of S-locus F-box brother (SFBB) genes, which are good candidates for the pollen S-determinant in apple and pear, indicated the presence of multiple S-allelic polymorphic F-box genes at the S-locus. In apple, two SFBB gene groups have been described, while there are at least three groups in pear. In this report, we identified five MdSLFB (S-RNase-linked F-box) genes from four different S-genotypes of apple. These genes showed pollen- and S-allele-specific expression with a high polymorphism among S-alleles. The phylogenetic tree suggested that some of them belong to SFBBα or β groups as described previously, while others
appear to be different from SFBBs. In particular, the presence of MdSLFB3 and MdSLFB9 suggested that there are more S-allelic polymorphic F-box gene groups in the S-locus besides α and β. Based on the sequence polymorphism of MdSLFBs, we developed an S-genotyping system for apple cultivars. In addition, we isolated twelve MdSLFB-like genes, which showed pollen-specific expression without S-allelic polymorphism. 相似文献
11.
A pentasaccharide repeating unit of the O-antigen of Hafnia alvei has been synthesized in a concise manner. High yielding glycosylation steps and minimum number of protecting group manipulation
steps are the key features of this synthesis. A two-step, one-pot phase transfer oxidation protocol has been applied for the
preparation of d-galacturonic acid.
C.D.R.I. communication no. 7245. 相似文献
12.
Eric Mortreau Sonia Siljak-Yakovlev Malika Cerbah Spencer C. Brown Hélène Bertrand Claudie Lambert 《Tree Genetics & Genomes》2010,6(1):137-148
The subsection Asperae of genus Hydrangea L. (Hydrangeaceae) has been investigated for three reasons: several ambiguous classifications concerning Hydrangea aspera have been published, unexpected differences in genome size among seven accessions have been reported Cerbah et al. (Theor
Appl Genet 103:45–51, 2001), and two atypical chromosome numbers (2n = 30 for Hydrangea involucrata and 2n = 34 for H. aspera) have been found when all other species of the genus present 2n = 36. Therefore, these two species and four subspecies of Hydrangea in all 29 accessions were analyzed for their genome size, chromosome number, and karyotype features. This investigation includes
flow cytometric measurements of nuclear DNA content and bases composition (GC%), fluorochrome banding for detection of GC-
and AT-rich DNA regions, and fluorescent in situ hybridisation (FISH) for chromosome mapping of 5 S and 18 S-5.8 S-26 S rDNA
genes. In the H. aspera complex, the genome size ranged from 2.98 (subsp. sargentiana) to 4.67 pg/2C (subsp. aspera), an exceptional intraspecific variation of 1.57-fold. The mean base composition was 40.5% GC. Our report establishes the
first karyotype for the species H. involucrata, and for the subspecies of H. aspera which indeed present different formulae, offering an element of discrimination. FISH and fluorochrome banding revealed the
important differentiation between these two species (H. involucrata and H. aspera) and among four subspecies of the H. aspera complex. Our results are in agreement with the Chinese classification that places the groups Kawakami and Villosa as two
different species: Hydrangea villosa Rehder and Hydrangea kawakami Hayata. This knowledge can contribute to effective germplasm management and horticultural use. 相似文献
13.
Hartung de Capriles C Mata-Essayag S Pérez C Colella MT Roselló A Olaizola C Abate SM 《Mycopathologia》2005,160(3):227-234
Over the past decades there has been a significant increase in fungal infections caused by Candida species, and continues to be common in immunocompromised individuals infected with the human immunodeficiency virus (HIV).
Although Candida albicans remains the fungal species most frequently isolated as an opportunistic oral pathogen, other non-albicans are often identified in this cohort of patients, including C. dubliniensis. This yeast is closely related to and shares many phenotypic characteristics with C. albicans. Colonies of these two species appear morphologically identical when not grown on special media. The shared phenotypic characteristics
of C. dubliniensis and C. albicans suggest that many C. dubliniensis isolates may have been misidentified as C. albicans in the past. The present studies aim is to recover and identify C. dubliniensis, and presumptive clinical C. albicans, from the oral cavities of HIV-seropositive individuals, comparing conventional media to obtain a simple, low-cost and reliable
identification system for C. dubliniensis. A total of 16 isolates (3,98%) had been obtained from 402 HIV infected individuals with recurrent oropharyngitis and were
identified as C. dubliniensis. Out of these C. dubliniensis isolates 19% were resistant, with MICs above 64 μg/ml to fluconazole. This constitutes, to the authors knowledge the first
recovery of this organism in Venezuela. 相似文献
14.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
15.
Christian Pietri Paulo Célio Alves José Melo-Ferreira 《European Journal of Wildlife Research》2011,57(2):313-321
The Italian hare, Lepus corsicanus, was first described in Corsica more than 100 years ago, but the knowledge on the status of the species in this island remains
scarce. Moreover, frequent introductions of thousands of individuals from other hare species, namely Lepus europaeus and Lepus granatensis, into Corsica are known to have occurred and an updated assessment of the prevalence of L. corsicanus in Corsica is therefore of utmost importance. Here, to estimate the relative prevalence of the hare species present in Corsica,
we conducted a molecular analysis on 67 samples collected by hunters between 2002 and 2007 in 36 Corsican communes. Sequencing
of portions of the nuclear gene transferrin and of the control region of the mitochondrial DNA allowed classifying most of
the collected samples as belonging to L. corsicanus (70.1%). Of the sampled Corsican communes, 86.1% contained this species, while only in 11.1%, L. europaeus was present. Three of the analyzed specimens showed an inconsistent molecular assignment between markers suggesting a hybrid
origin: L. corsicanus × L. europaeus, L. corsicanus × L. granatensis, and L. europaeus × L. granatensis. The first two cases of hybridization had never been described in nature, even in studies focusing on hares from Italy where
L. corsicanus and L. europaeus are often sympatric. These results stress the real risk of corrosion of the native gene pool of L. corsicanus via hybridization with introduced species. We highlight the need of urgently rethinking the management plan of hare populations
in Corsica. 相似文献
16.
The genes encoding an enantioselective nitrile hydratase (NHase) from Rhodococcus erythropolis AJ270 have been cloned and an active NHase has been produced in Escherichia coli. Maximal activity was found when the genes encoding the α- and β-subunits were transcribed as one unit and the gene encoding
the P44k activator protein as a separate ORF on a single replicon. Addition of n-butyric acid and FeSO4 could improve NHase activity. Coexpression of the GroEL-GroES chaperone proteins increased activity in the absence of P44k
protein but had no effect in the presence of P44k. The recombinant enzyme was highly enantioselective in the synthesis of
S-(+)-3-benzoyloxy- 4-cyanobutyramide from the prochiral substrate 3-benzoyloxyglutaronitrile. 相似文献
17.
In this study, we report the cloning, recombinant expression, and biochemical characterization of a heat-stable CMP-N-acylneuraminic acid (NeuAc) synthetase from Clostridium thermocellum ATCC 27405. A high throughput electrospray ionization mass spectrometry (ESI-MS)-based assay demonstrates that the enzyme
has an absolute requirement for a divalent cation for activity and reaches maximum activity in the presence of 10 mM Mn2+. The enzyme is active at pH 8–13 in Tris–HCl buffer and at 37–60 °C, and maximum activity is observed at pH 9.5 and 50 °C
in the presence of 0.2 mM dithiothreitol. In addition to NeuAc, the enzyme also accepts the analog N-glycolylneuraminic acid (NeuGc) as a substrate. The apparent Michaelis constants for cytidine triphosphate and NeuAc or NeuGc
are 240 ± 20, 130 ± 10, and 160 ± 10 μM, respectively, with corresponding turnover numbers of 3.33, 2.25, and 1.66 s−1, respectively. An initial velocity study of the enzymatic reaction indicates an ordered bi–bi catalytic mechanism. In addition
to demonstration of a thermostable and substrate-tolerant enzyme, confirmation of the biochemical function of a gene for CMP-NeuAc
synthetase in C. thermocellum also opens the question of the biological function of CMP-NeuAc in such nonpathogenic microorganisms. 相似文献
18.
A rapid and efficient plant regeneration protocol for a wide range of alfalfa genotypes was developed via direct organogenesis. Through a successive excision of the newly developed apical and axillary shoots, a lot of adventitious
buds were directly induced from the cotyledonary nodes when hypocotyl of explants were vertically inserted into modified Murashige
and Skoog (MS) medium supplemented with 0.025 mg dm−3 thidiazuron (TDZ) and 3 mg dm−3 AgNO3. When the lower part of shoots excised from explants were immersed into the liquid medium with 1.0 mg dm−3 α-naphthaleneacetic acid (NAA) for 2 min, and then transferred to hormone free half-strength MS medium, over 83.3 % of the
shoots developed roots, and all plantlets could acclimatize and establish in soil. The protocol has been successfully applied
to eight genotypes, with regeneration frequencies ranging from 63.8 to 82.5 %. 相似文献
19.
Ely Zayova Ira Stancheva Maria Geneva Maria Petrova Rumiana Vasilevska-Ivanova 《Central European Journal of Biology》2012,7(4):698-707
An effective in vitro protocol for rapid clonal propagation of Echinacea purpurea (L.) Moench through tissue culture was described. The in vitro propagation procedure consisted of four stages: 1) an initial stage - obtaining seedlings on Murashige and Skoog (MS) basal
medium with 0.1 mg L−1 6-benzylaminopurine, 0.1 mg L−1 α-naphthalene acetic acid and 0.2 mg L−1 gibberellic acid; 2) a propagation stage — shoot formation on MS medium supplemented with 1 mg L−1 6-benzylaminopurine alone resulted in 9.8 shoots per explant and in combination with 0.1 mg L−1 α-naphthalene acetic acid resulted in 16.2 shoots per explant; 3) rooting stage — shoot rooting on half strength MS medium
with 0.1 mg L−1 indole-3-butyric acid resulted in 90% rooted microplants; 4) ex vitro acclimatization of plants. The mix of peat and perlite was the most suitable planting substrate for hardening and ensured
high survival frequency of propagated plants. Significant higher levels were observed regarding water-soluble and lipid-soluble
antioxidant capacities (expressed as equivalents of ascorbate and α-tocopherol) and total pnenols content in extracts of Echinaceae flowers derived from in vitro propagated plants and adapted to field conditions in comparison with traditionally cultivated plants. 相似文献
20.
Senka S. Vidović Ibrahim O. Mujić Zoran P. Zeković Žika D. Lepojević Vesna T. Tumbas Aida I. Mujić 《Food biophysics》2010,5(1):49-58
Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study
was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant
compounds, scavenging capacity on DPPH˙, OH˙, and O2˙− radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content
of total phenols (41.82 ± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/diode array detector analysis, the main antioxidant compound, variegatic acid,
has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical–scavenging
evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016 ± 0.0003 mg/ml. The extracts
were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spin-trapping
and spin-probing techniques, activity against relevant reactive species, ˙OH and O2˙− radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for ˙OH radical
reduction, and both exhibited significant capacity for scavenging O2˙− radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant
resource. 相似文献