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951.
High production of laccase by a new basidiomycete, <Emphasis Type="Italic">Trametes</Emphasis> sp 总被引:1,自引:0,他引:1
A new basidiomycete, Trametes sp. 420, produced laccase at 6,810 U l−1 (268 mg, 25.4 U mg−1 protein for guaiacol) in glucose medium and 7,870 U l−1 (310 mg) in cellobiose medium with induction by 0.5 mM Cu2+ and 6 mM o-toluidine. Laccase isozyme E (LacE) was the sole laccase in the fermentation products. It was stable at pH 5–9 and below
70°C over 30 min. The K
m values of LacE for four substrates (guaiacol ABTS, 2,6-dimethoxyphenol and syringaldazine) varied from 5 to 245 μM. The activity
of LacE was strongly inhibited by NaN3 but not by EDTA or dimethylsulfoxide. LacE at 0.5 U l−1 could decolorize industrial dyes. The open reading frame of the lacE gene was 2,130 bp and was interrupted by 10 introns. It displayed a high homology to laccases from other fungi.
Pingui Tong and Yuzhi Hong contributed equally to the study 相似文献
952.
Various approaches have been developed to define conservation units for plant and animal species. In this study we combined
nuclear microsatellites (from a previous published study) and chloroplast microsatellites (assessed in the present study),
leaf and seed morphology traits and abiotic variables (climate and soil) to define evolutionary significant units (ESU) of
Santalum austrocaledonicum, a tree species growing in New Caledonia. Results for chloroplast microsatellites showed that the total population heterozygosity
was␣high, (H
cp = 0.84) but varied between islands. Differentiation was strong in the total population (F
stcp = 0.66) but also within the main island Grande Terre (F
stcp = 0.73) and within Iles Loyauté (F
stcp = 0.52), highlighting a limited gene flow between populations. These results confirmed those obtained with nuclear microsatellites.
The cluster analysis on molecular markers discriminated two main groups constituted by the populations of Grande Terre and
the populations of Iles Loyauté. A principal component analysis of leaf and seed morphology traits singled out the populations
of Iles Loyauté and the western populations of Grande Terre. Quantitative genetic analyses showed that the variation between
populations was under genetic control (broad sense heritability close to 80%). A high correlation between rainfall and morphological
traits suggested an impact of climate on this variation. The integration of these results allows to define two ESUs, one corresponding
to Grande Terre and Ile des Pins and the other the Iles Loyauté archipelago. This study stresses the need to restore some
populations of Grande Terre that are currently threatened by their small size. 相似文献
953.
Yin Li Zhiqiang Liu Fengjie Cui Yingying Xu Hui Zhao 《World journal of microbiology & biotechnology》2007,23(6):837-843
A new strain of Penicillium sp. ZH-30 that produces xylanase was isolated from soil. According to the morphology and comparison of internal transcribed
spacer (ITS) rDNA gene sequence, the strain Penicillium sp. ZH-30 was identified as a strain of Penicillium oxalicum. When xylan or wheat bran was used as substrate at 30°C for 3 days under submerged cultivation, xylanase production was 5.3
and 13.3 U ml−1, respectively. The temperature and pH for optimum activity were 50°C and 5.0–6.0, respectively. 相似文献
954.
Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake,Alaska 总被引:3,自引:0,他引:3
Long-term fertilization of acidic tussock tundra has led to changes in plant species composition, increases in aboveground
production and biomass and substantial losses of soil organic carbon (SOC). Root litter is an important input to SOC pools,
although little is known about fine root demography in tussock tundra. In this study, we examined the response of fine root
production and live standing fine root biomass to short- and long-term fertilization, as changes in fine root demography may
contribute to observed declines in SOC. Live standing fine root biomass increased with long-term fertilization, while fine
root production declined, reflecting replacement of the annual fine root system of Eriophorum vaginatum, with the long-lived fine roots of Betula nana. Fine root production increased in fertilized plots during an unusually warm growing season, but remained unchanged in control
plots, consistent with observations that B. nana shows a positive response to climate warming. Calculations based on a few simple assumptions suggest changes in fine root
demography with long-term fertilization and species replacement could account for between 20 and 39% of the observed declines
in SOC stocks. 相似文献
955.
Chemotherapy and zoledronate sensitize solid tumour cells to Vγ9Vδ2 T cell cytotoxicity 总被引:1,自引:0,他引:1
Combinations of cellular immune-based therapies with chemotherapy and other antitumour agents may be of significant clinical
benefit in the treatment of many forms of cancer. Gamma delta (γδ) T cells are of particular interest for use in such combined
therapies due to their potent antitumour cytotoxicity and relative ease of generation in vitro. Here, we demonstrate high
levels of cytotoxicity against solid tumour-derived cell lines with combination treatment utilizing Vγ9Vδ2 T cells, chemotherapeutic
agents and the bisphosphonate, zoledronate. Pre-treatment with low concentrations of chemotherapeutic agents or zoledronate
sensitized tumour cells to rapid killing by Vγ9Vδ2 T cells with levels of cytotoxicity approaching 90%. In addition, zoledronate
enhanced the chemotherapy-induced sensitization of tumour cells to Vγ9Vδ2 T cell cytotoxicity resulting in almost 100% lysis
of tumour targets in some cases. Vγ9Vδ2 T cell cytotoxicity was mediated by perforin following TCR-dependent and isoprenoid-mediated
recognition of tumour cells. Production of IFN-γ by Vγ9Vδ2 T cells was also induced after exposure to sensitized targets.
We conclude that administration of Vγ9Vδ2 T cells at suitable intervals after chemotherapy and zoledronate may substantially
increase antitumour activities in a range of malignancies.
Financial
support and conflicts of interest: This study was supported by grants from Medinet (Japan), and Suncorp Metway and Gallipoli Research Foundation (Australia).
No financial or commercial interests arise from this study. Informed consent: This study was approved by Human Research Ethics Committees of the University of Queensland and Greenslopes Private Hospital
and informed consent was obtained from all subjects. 相似文献
956.
957.
This work was to characterize the generation of nitric oxide (NO) in Taxus yunnanensis cells induced by a fungal-derived cerebroside and the signal role of NO in the elicitation of plant defense responses and
taxol production. (2S,2′R,3R,3′E,4E,8E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine at 10 μg/ml induced a rapid and dose-dependent NO production
in the Taxus cell culture, reaching a maximum within 5 h of the treatment. The NO donor sodium nitroprusside (SNP) potentiated cerebroside-induced
H2O2 production and cell death. Inhibition of nitric oxide synthase activity by phenylene-1,3-bis(ethane-2-isothiourea) dihydrobromide
or scavenging NO by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide partially blocked the cerebroside-induced
H2O2 production and cell death. Moreover, NO enhanced cerebroside-induced activation of phenylalanine ammonium-lyase and accumulation
of taxol in cell cultures. These results are suggestive of a role for NO as a new signal component for activating the cerebroside-induced
defense responses and secondary metabolism activities of plant cells.
Taxol is a trademark of Bristol-Myers Squibb, Madison, NJ. 相似文献
958.
Pantolestinae is a eutherian subfamily of mammals whose members are known from the middle early Paleocene through at least
the beginning of the Oligocene of North America. They are also known from Europe, and possibly Africa. A lack of information
on pantolestine skulls has prevented the use of cranial anatomy in evaluation of this group’s enigmatic higher-level phylogenetic
relationships. Conversely, postcranial skeletons are well known and locomotor interpretations based on them are robust. The
most complete known skull of a pantolestine, Pantolestes longicaudus (YPM 13525), is described here and compared to potential close fossil relatives and extant mammals. Semicircular canal morphology
is used to test locomotor hypotheses.
YPM 13525 lacks an ossified bulla. It has a mediolaterally broad basioccipital, a large entoglenoid process, and a deeply
incised glaserian fissure of the squamosal, caudal and rostral tympanic processes on the petrosal, a foramen for an internal
carotid artery (ICA) that entered the tympanic cavity from a posteromedial position, bony tubes enclosing the main stem and
transpromontorial branch of the ICA, a large anterior carotid foramen formed within the basisphenoid, evidence of a stapedial
artery ramus superior, a groove on the dorsal aspect of the basisphenoid leading to the piriform fenestra possibly for drainage
of the cavernous sinus to an extracranial inferior petrosal sinus, a dorsum sellae with well-developed posterior clinoid processes,
a foramen rotundum within the alisphenoid, and a sphenorbital fissure between the alisphenoid and orbitosphenoid. Overall,
the morphology is not strikingly similar to any potential close relative and the phylogenetic position of Pantolestinae cannot
be estimated without cladistic analysis of a character matrix that includes this new morphology and broadly samples extant
and extinct eutherian taxa. Semicircular canal morphology differs from that of two likely terrestrial Paleocene mammals, Aphronorus (another pantolestid) and Eoryctes (a palaeoryctid), suggesting a different, possibly semi-aquatic, lifestyle for Pantolestes. 相似文献
959.
960.
Plants have large families of proteins sharing a conserved eight-cysteine-motif (8CM) domain. The biological functions of
these proteins are largely unknown. EARLI1 is a cold responsive Arabidopsis gene that encodes a hybrid proline-rich protein (HyPRP) with a three-domain architecture:
a putative signal peptide at the N-terminus, a proline-rich domain (PRD) in the middle, and an 8CM domain at the C-terminus.
We report here that yeast cells expressing different EARLI1 genes had significantly higher rates of freezing survival than empty-vector transformed controls. Arabidopsis plants with
knocked down EARLI1 genes had an increased tendency for freezing-induced cellular damage. EARLI1-GFP fluorescence in transgenic plants and immunoblot
analyses using protoplasts suggested cell wall localization for EARLI1 proteins. Immunoblot analyses showed that EARLI1 proteins
form higher order complexes in plants, and that the PRD is a soluble and the 8CM an insoluble protein domain. We propose that
EARLI1 proteins have a bimodular architecture in which the PRD may interact with the cell wall and the 8CM domain with the
plasma membrane to protect the cells during freezing stress. 相似文献