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941.
942.
The production of recombinant proteins in plants is an active area of research and many different high-value proteins have
now been produced in plants. Tobacco leaves have many advantages for recombinant protein production particularly since they
allow field production without seeds, flowers or pollen and therefore provide for contained production. Despite these biosafety
advantages recombinant protein accumulation in leaves still needs to be improved. Elastin-like polypeptides are repeats of
the amino acids “VPGXG” that undergo a temperature dependant phase transition and have utility in the purification of recombinant
proteins but can also enhance the accumulation of recombinant proteins they are fused to. We have used a 11.3 kDa elastin-like
polypeptide as a fusion partner for three different target proteins, human interleukin-10, murine interleukin-4 and the native
major ampullate spidroin protein 2 gene from the spider Nephila clavipes. In both transient analyses and stable transformants the concentrations of the fusion proteins were at least an order of
magnitude higher for all of the fusion proteins when compared to the target protein alone. Therefore, fusions with a small
ELP tag can be used to significantly enhance the accumulation of a range of different recombinant proteins in plant leaves.
An erratum to this article can be found at 相似文献
943.
Deciduous forests may respond differently from coniferous forests to the anthropogenic deposition of nitrogen (N). Since fungi,
especially ectomycorrhizal (EM) fungi, are known to be negatively affected by N deposition, the effects of N deposition on
the soil microbial community, total fungal biomass and mycelial growth of EM fungi were studied in oak-dominated deciduous
forests along a nitrogen deposition gradient in southern Sweden. In-growth mesh bags were used to estimate the production
of mycelia by EM fungi in 19 oak stands in the N deposition gradient, and the results were compared with nitrate leaching
data obtained previously. Soil samples from 154 oak forest sites were analysed regarding the content of phospholipid fatty
acids (PLFAs). Thirty PLFAs associated with microbes were analysed and the PLFA 18:2ω6,9 was used as an indicator to estimate
the total fungal biomass. Higher N deposition (20 kg N ha−1 y−1 compared with 10 kg N ha−1 y−1) tended to reduce EM mycelial growth. The total soil fungal biomass was not affected by N deposition or soil pH, while the
PLFA 16:1ω5, a biomarker for arbuscular mycorrhizal (AM) fungi, was negatively affected by N deposition, but also positively
correlated to soil pH. Other PLFAs positively affected by soil pH were, e.g., i14:0, a15:0, 16:1ω9, a17:0 and 18:1ω7, while
some were negatively affected by pH, such as i15:0, 16:1ω7t, 10Me17:0 and cy19:0. In addition, N deposition had an effect
on the PLFAs 16:1ω7c and 16:1ω9 (negatively) and cy19:0 (positively). The production of EM mycelia is probably more sensitive
to N deposition than total fungal biomass according to the fungal biomarker PLFA 18:2ω6,9. Low amounts of EM mycelia covaried
with increased nitrate leaching, suggesting that EM mycelia possibly play an important role in forest soil N retention at
increased N input. 相似文献
944.
Characteristic features and biotechnological applications of cross-linked enzyme aggregates (CLEAs) 总被引:1,自引:0,他引:1
Sheldon RA 《Applied microbiology and biotechnology》2011,92(3):467-477
Cross-linked enzyme aggregates (CLEAs) have many economic and environmental benefits in the context of industrial biocatalysis.
They are easily prepared from crude enzyme extracts, and the costs of (often expensive) carriers are circumvented. They generally
exhibit improved storage and operational stability towards denaturation by heat, organic solvents, and autoproteolysis and
are stable towards leaching in aqueous media. Furthermore, they have high catalyst productivities (kilograms product per kilogram
biocatalyst) and are easy to recover and recycle. Yet another advantage derives from the possibility to co-immobilize two
or more enzymes to provide CLEAs that are capable of catalyzing multiple biotransformations, independently or in sequence
as catalytic cascade processes. 相似文献
945.
Factors influencing the spatial distribution of forest plant species in hedgerows of North-western Germany 总被引:2,自引:0,他引:2
In North-western Germany woodland fragmentation has caused a decline in many forest plant species. Hedgerows partly offer
a similar environment as forests and have been identified as potential habitats for forest plants in various studies from
North America and Western Europe. The objective of this study was to examine whether this applies also to Central Europe and
which variables affect the spatial distribution and abundance of forest plant species in hedgerows on a local scale. Three
hedgerow networks north of the city of Bremen, Germany, were selected as study areas and divided into totally 515 hedgerow
segments. In each segment we recorded all vascular plants and a large number of explanatory variables relating to structure,
spatial configuration, environment and management. Averaged across species there was a predominant effect of environmental
factors on the occurrence of forest species in the hedgerows, followed by spatial configuration and management. Hedgerow structure
was found to be less important. In general, forest species were favored by low nutrient and light availability as well as
high connectivity with other hedgerows or forest; they avoided hedgerows with a west-easterly orientation and an adjacent
land use in the form of fields or grasslands. Forest species found and not found in hedgerows did not differ in their environmental
preferences or life history traits. The number of threatened forest species in the hedgerows, however, was lower than expected
with respect to their overall proportion to the total number of forest species in the region. 相似文献
946.
João Marcelo Alvarenga Braga 《Kew Bulletin》2008,63(2):309-314
Summary
Calathea dryadica and Calathea reginae are described, circumscribed and illustrated. These new species are probably endemic to the Atlantic Forest of Rio de Janeiro
State in Southeast Brazil and are considered critically endangered because of the restricted geographic area of occurrence,
sometimes enclosed by densely urbanised areas. 相似文献
947.
Hongjian Wan Zhenguo Zhao Ahmed Abbas Malik Chuntao Qian Jinfeng Chen 《BMC plant biology》2010,10(1):186
Background
Due to the variation and mutation of the races of Pseudoperonospora cubensis, downy mildew has in recent years become the most devastating leaf disease of cucumber worldwide. Novel resistance to downy mildew has been identified in the wild Cucumis species, C. hystrix Chakr. After the successful hybridization between C. hystrix and cultivated cucumber (C. sativus L.), an introgression line (IL5211S) was identified as highly resistant to downy mildew. Nucleotide-binding site and leucine-rich repeat (NBS-LRR) genes are the largest class of disease resistance genes cloned from plant with highly conserved domains, which can be used to facilitate the isolation of candidate genes associated with downy mildew resistance in IL5211S. 相似文献948.
To obtain better performing laccases for textile dyes decolorization, random mutagenesis of Lac591, a metagenome-derived alkaline
laccase, was carried out. After three rounds of error-prone PCR and high-throughput screening by assaying enzymatic activity
toward the phenolic substrate 2,6-dimethoxyphenol (2,6-DMP), a mutant (Lac3T93) with remarkably improved enzymatic activity
was obtained. Sequence analysis revealed that four amino acid substitutions (N40S, V55A, F62L, and E316V) were accumulated
in the Lac3T93. Compared to the wild-type enzyme, the specific activity of Lac3T93 toward 2,6-DMP was increased to 4.8-fold
(61.22 U/mg), and its optimal temperature and pH were changed to 60°C and 8.0 from 55°C and 7.5 of the wild-type enzyme, respectively.
Furthermore, the degradation ability of Lac3T93 for textile dyes was investigated, and the new variant represented improved
decolorization percentage for four industrial dyes with complex phenyl structure (Basic Blue 3, Methylene Blue, Bromophenol
Blue, and Crystal Violet) and higher decolorization efficiency for Indigo Carmine than that of the parent enzyme. Furthermore,
the decolorization percentage of Lac3T93 for five dyes in the absence of hydroxybenzotrizole (HBT) is clearly higher than
those of the wild-type enzyme with 1 mM HBT, and HBT can further improve its decolorization ability. 相似文献
949.
Laura Bedin Denardi Jéssica Tairine Keller Vanessa Oliveira Débora Alves Nunes Mario Janio Morais Santurio Sydney Hartz Alves 《Mycopathologia》2017,182(9-10):819-828
In this study, we evaluated the in vitro activity of echinocandins, azoles, and amphotericin B alone and in combination against echinocandin/azole-sensitive and echinocandin/azole-resistant Candida glabrata isolates. Susceptibility tests were performed using the broth microdilution method in accordance with the Clinical and Laboratory Standards Institute document M27-A3. The checkerboard method was used to evaluate the fractional inhibitory concentration index of the interactions. Cross-resistance was observed among echinocandins; 15% of the isolates resistant to caspofungin were also resistant to anidulafungin and micafungin. Synergistic activity was observed in 70% of resistant C. glabrata when anidulafungin was combined with voriconazole or posaconazole. Higher (85%) synergism was found in the combination of caspofungin and voriconazole. The combinations of caspofungin with fluconazole, posaconazole and amphotericin B, micafungin with fluconazole, posaconazole and voriconazole, and anidulafungin with amphotericin B showed indifferent activities for the majority of the isolates. Anidulafungin combined with fluconazole showed the same percentage of synergism and indifference (45%). Antagonism was detected in 50% of isolates when micafungin was combined with amphotericin B. Combinations of echinocandins and antifungal azoles have great potential for in vivo assays which are required to evaluate the efficacy of these combinations against multidrug-resistant C. glabrata strains. 相似文献
950.
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