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41.
【背景】杨树溃疡病是一种主要由葡萄座腔菌引起的杨树枝干病害,危害严重。前期从杨树中分离到一株内生拮抗细菌N6-34,研究表明该菌株拮抗效果好,对多种植物病原菌均有较强的拮抗作用。【目的】对拮抗细菌N6-34产生的抗菌活性物质进行分离纯化,并鉴定了活性物质组分的结构。【方法】通过硫酸铵盐析、甲醇抽提、分子筛、高效液相色谱等方法分离纯化N6-34菌株的抗菌活性物质,并对其进行结构鉴定。【结果】N6-34菌株发酵液经多步分离纯化,共获得14个组分,其中有13个组分具有抗菌活性,经一级质谱分析,获得了13种抗菌活性组分的分子量;经二级质谱分析,将13种抗菌活性物质鉴定为Fengycin A或Fengycin B的同系物或同分异构体。【结论】从N6-34菌株发酵液中分离获得了13种抗菌成分,为杨树溃疡病的生物防治提供了理论依据。 相似文献
42.
Surface Engineering of TiO2 ETL for Highly Efficient and Hysteresis‐Less Planar Perovskite Solar Cell (21.4%) with Enhanced Open‐Circuit Voltage and Stability
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Interfacial studies and band alignment engineering on the electron transport layer (ETL) play a key role for fabrication of high‐performance perovskite solar cells (PSCs). Here, an amorphous layer of SnO2 (a‐SnO2) between the TiO2 ETL and the perovskite absorber is inserted and the charge transport properties of the device are studied. The double‐layer structure of TiO2 compact layer (c‐TiO2) and a‐SnO2 ETL leads to modification of interface energetics, resulting in improved charge collection and decreased carrier recombination in PSCs. The optimized device based on a‐SnO2/c‐TiO2 ETL shows a maximum power conversion efficiency (PCE) of 21.4% as compared to 19.33% for c‐TiO2 based device. Moreover, the modified device demonstrates a maximum open‐circuit voltage (Voc) of 1.223 V with 387 mV loss in potential, which is among the highest reported value for PSCs with negligible hysteresis. The stability results show that the device on c‐TiO2/a‐SnO2 retains about 91% of its initial PCE value after 500 h light illumination, which is higher than pure c‐TiO2 (67%) based devices. Interestingly, using a‐SnO2/c‐TiO2 ETL the PCE loss was only 10% of initial value under continuous UV light illumination after 30 h, which is higher than that of c‐TiO2 based device (28% PCE loss). 相似文献
43.
Molecular evolution of cytochrome c oxidase: rate variation among subunit VIa isoforms 总被引:3,自引:1,他引:2
Schmidt TR; Jaradat SA; Goodman M; Lomax MI; Grossman LI 《Molecular biology and evolution》1997,14(6):595-601
Cytochrome c oxidase (COX) consists of 13 subunits, 3 encoded in the
mitochondrial genome and 10 in the nucleus. Little is known of the role of
the nuclear-encoded subunits, some of which exhibit tissue-specific
isoforms. Subunit VIa is unique in having tissue-specific isoforms in all
mammalian species examined. We examined relative evolutionary rates for the
COX6A heart (H) and liver (L) isoform genes along the length of the
molecule, specifically in relation to the tissue-specific function(s) of
the two isoforms. Nonsynonymous (amino acid replacement) substitutions in
the COX6AH gene occurred more frequently than in the ubiquitously expressed
COX6AL gene. Maximum-parsimony analysis and sequence divergences from
reconstructed ancestral sequences revealed that after the ancestral COX6A
gene duplicated to yield the genes for the H and L isoforms, the sequences
encoding the mitochondrial matrix region of the COX VIa protein experienced
an elevated rate of nonsynonymous substitutions relative to synonymous
substitutions. This is expected for relaxed selective constraints after
gene duplication followed by purifying selection to preserve the
replacements with tissue-specific functions.
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A novel spray bioreactor for the proliferation of plant callus; Hyoscyamus niger and Arnebia pulchra
Goojgi Sara Tahmasebi Tavakoli Mahsa Haghbeen Kamahldin Mousavi Amir Piri Khosro 《Biotechnology letters》2022,44(2):333-340
Biotechnology Letters - Unlike plant cell suspension culture, the proliferation of callus in bioreactors has received inadequate attention. The magnificent potential of plant callus becomes more... 相似文献
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Zoe Inman Helen Martin SA Paul Chubb 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2009,30(3):141-151
Background
The lack of guidelines on reporting standards for protein electrophoresis may have led to significant differences in reports from different laboratories.Objective
To determine the extent of variation in reporting of protein electrophoresis results in Australia and New Zealand.Method
Questionnaires were distributed to laboratories throughout Australia and New Zealand asking about protein electrophoresis practices and reporting.Results
Extensive variation was found in the following reporting practices: (a) units for urine Bence Jones protein (BJP); (b) reporting absence of a paraprotein rather than a normal pattern; (c) numerical reporting of all protein fractions or only the paraprotein; (d) warning of possible inaccuracy in the serum immunoglobulin result of the paraprotein type; (e) co-migration of a paraprotein with a normal serum protein; (f) use of a confirmatory test when a known paraprotein is no longer detectable.Conclusions
A working party should be established to make recommendations on the reporting of protein electrophoresis. Implementation of such recommendations should reduce both report variation between laboratories and the risk of misinterpretation of reports. 相似文献50.
THAÍSA SALA MICHELAN SIDINEI MAGELA THOMAZ ROGER PAULO MORMUL PRISCILLA CARVALHO 《Freshwater Biology》2010,55(6):1315-1326
1. The issue of freshwater species being threatened by invasion has become central in conservation biology because inland waters exhibit the highest species richness per unit area, but apparently have the highest extinctions rates on the planet. 2. In this article, we evaluated the effects of an exotic, invasive aquatic grass (Urochloa subquadripara– tropical signalgrass) on the diversity and assemblage composition of native macrophytes in four Neotropical water bodies (two reservoirs and two lakes). Species cover was assessed in quadrats, and plant biomass was measured in further quadrats, located in sites where tropical signalgrass dominated (D quadrats) and sites where it was not dominant or entirely absent (ND quadrats). The effects of tropical signalgrass on macrophyte species richness, Shannon diversity and number of macrophyte life forms (a surrogate of functional richness) were assessed through regressions, and composition was assessed with a DCA. The effects of tropical signalgrass biomass on the likelihood of occurrence of specific macrophyte life forms were assessed through logistic regression. 3. Tropical signalgrass had a negative effect on macrophyte richness and Shannon and functional diversity, and also influenced assemblage composition. Emergent, rooted with floating stems and rooted submersed species were negatively affected by tropical signalgrass, while the occurrence of free‐floating species was positively affected. 4. Our results suggest that competition with emergent species and reduction of underwater radiation, which reduces the number of submersed species, counteract facilitation of free‐floating species, contributing to a decrease in plant diversity. In addition, homogenisation of plant assemblages shows that tropical signalgrass reduces the beta diversity in the macrophyte community. 5. Although our results were obtained at fine spatial scales, they are cause for concern because macrophytes are an important part of freshwater diversity. 相似文献