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31.
Drawing on evidence from a study of Black Police Associations in English and Welsh constabularies, this article addresses perceived changes in the articulation of racialized relations within the police during the years following Lord Macpherson's Report about the police investigation of Stephen Lawrence's murder. Association officials argued that overt racism has been replaced by covert racism, evidence of which is, by definition, difficult to establish. Black Police Association officials’ and senior officers’ views of this change are discussed. Sources of evidence of covert racism are described and analysed, often related to Macpherson's definition of ‘institutional racism’. The wider implications of the article for the study of race and ethnicity are then discussed, with particular reference to Brubaker's recent work on ethnicity as cognition, which underpins the analysis of all the data gathered.  相似文献   
32.
Each year 25–75% of banana and plantain yields are lost because of rhizome damages caused by banana weevil (Cosmopolites sordidus) in growing regions of sub‐Saharan Africa. However, the specific plant defence response of the rhizome tissue in relation to the C. sordidus attack is unknown. Consequently, in this study, we evaluated whether plant defence substances in the rhizome are correlated with the degree of larval damage and whether applications of methyl jasmonate (MJ) elicit a greater induction of the plant defence potential against C. sordidus. Moreover, we attempted to reveal cellular modifications in response to the root feeding herbivore through histochemical staining. The banana cultivars “Km5” and “Mbwazirume” with tolerance and susceptibility to C. sordidus, respectively, were used in a pot experiment to evaluate percent rhizome damage, leaf chlorophyll content, total phenolic content (TPC), antioxidant capacity and cell morphology in response to C. sordidus attack and/or MJ applications compared to untreated control plants. We found that C. sordidus‐induced rhizome damage was 30% in the susceptible cultivar but less than 5% in the tolerant cultivar. The percent rhizome damage was not related to leaf chlorophyll content but showed a significant negative linear relationship to both TPC and antioxidant capacity. Larvae feeding induced a considerably greater increase of polyphenolic defence compounds in Km5 than in Mbwazirume; however, this response was opposite in the MJ treatment, suggesting that the phytohormone induced the susceptible plant to invest more into the synthesis of defence chemicals that in turn lead to reduced C. sordidus damage. Tissue staining demonstrated a greater deposition of lignin and suberin in C. sordidus challenged rhizome, presumably to seal off healthy tissue with a physical barrier from continued pest attack. It is concluded that MJ induces polyphenolics in susceptible Mbwazirume banana that reduced C. sordidus damage.  相似文献   
33.
The in vivo biodegradation of the diazo dye Reactive Black 5 (RB5) by Phanerochaete chrysosporium immobilised on cubes of nylon sponge and on sunflower-seed shells (SS) in laboratory-scale bioreactors was investigated. The SS cultivation led to the best results with a decolouration percentage of 90.3% in 72 h for an initial RB5 concentration of 100 mg/L. It was found that the addition of 0.4 mM veratryl alcohol (VA) into the medium considerably increased the decolouration rate in SS cultivation. However, the addition of VA had no effect in the nylon cultivation. Thin layer chromatography (TLC) revealed that RB5 was transformed into one metabolite after 24 h. UV-vis spectroscopy and Fourier Transform Infrared (FT-IR) also confirmed the biodegradation of RB5. Toxicity of RB5 solutions before and after fungal treatment was assayed using Sinorhizobium meliloti as a sensitive soil microorganism. P. chrysosporium transformed the toxic dye RB5 into a non-toxic product.  相似文献   
34.
Banana weevil females laid on an average 2.7 eggs/week in rhizome material and 0.7 eggs/week in pseudostem material in the laboratory. At extremely high weevil population densities the egg-laying activity declined. Under controlled field conditions 0.7 eggs/week were laid in banana suckers and 1.3 eggs/week in stumps of harvested suckers. 25% of the weevil stages found in suckers in the field were eggs of which 78% were laid in the rhizome and 22% in the pseudostem base. The majority of eggs was deposited in the crown area of the rhizome followed by the remaining surface area of the rhizome, the walls of abandoned larval tunnels in rhizome and pseudostem and the leaf sheaths. 58% of the eggs found were considered accessible to egg predators.  相似文献   
35.
Aspergillus niger and Aspergillus carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspergilli produce important mycotoxins, ochratoxins A, and the fumonisins. To facilitate the study of the black aspergilli–maize interactions with maize during the early stages of infections, we developed a method that used the enhanced yellow fluorescent protein (eYFP) and the monomeric red fluorescent protein (mRFP1) to transform A. niger and A. carbonarius, respectively. The results were constitutive expressions of the fluorescent genes that were stable in the cytoplasms of hyphae and conidia under natural environmental conditions. The hyphal in planta distribution in 21-day-old seedlings of maize were similar wild type and transformants of A. niger and A. carbonarius. The in planta studies indicated that both wild type and transformants internally colonized leaf, stem and root tissues of maize seedlings, without any visible disease symptoms. Yellow and red fluorescent strains were capable of invading epidermal cells of maize roots intercellularly within the first 3 days after inoculation, but intracellular hyphal growth was more evident after 7 days of inoculation. We also tested the capacity of fluorescent transformants to produce ochratoxin A and the results with A. carbonarius showed that this transgenic strain produced similar concentrations of this secondary metabolite. This is the first report on the in planta expression of fluorescent proteins that should be useful to study the internal plant colonization patterns of two ochratoxigenic species in the Aspergillus section Nigri.  相似文献   
36.
Black cumin (Nigella sativa) seed protein (BCSP) was individually hydrolyzed with pepsin, trypsin, and α-chymotrypsin. After ultrafiltration, the α-chymotrypsin hydrolysate (< 3 kDa) exhibited the highest ACE inhibitory (ACEI) activity with an IC50 value of 34.4 ± 1.5 μg/mL. This hydrolysate was orthogonally fractionalized using reversed-phase high-performance liquid chromatography (RP-HPLC) and strong cation exchange (SCX) chromatography, and the most active RP-HPLC and SCX fractions (F7 and H4, respectively) were individually screened out by ACEI assay. These two fractions were analyzed with liquid chromatography-tandem mass spectrometry (LC–MS/MS) followed by automated de novo peptide sequencing, and totally 43 ACEI candidate peptides were identified. Three overlapping peptides (VTPVGVPKW, VVTPVGVPKW, and LVLTL) were simultaneously contained in both fractions, and VTPVGVPKW (VW-9) was speculated as to the most potent ACEI peptide based on the in silico analysis. Synthetic VW-9 was used to confirm the identity, and a remarkable IC50 value of VW-9 (1.8 ± 0.09 μM) was determined. Preincubation and inhibition mechanism studies indicated that VW-9 was a true inhibitor as well as a non-competitive inhibitor on ACE, which was further illustrated with the molecular docking simulation. Our study revealed that the application of VW-9 to antihypertensive products is promising.  相似文献   
37.
Beauveria bassiana is considered a virulent pathogen against the banana weevil Cosmopolites sordidus. However, current field application techniques for effective control against this pest remain a limitation and an alternative method for effective field application needs to be investigated. Three screenhouse experiments were conducted to determine the ability of B. bassiana to form an endophytic relationship with tissue culture banana (Musa spp.) plants and to evaluate the plants for possible harmful effects resulting from this relationship. Three Ugandan strains of B. bassiana (G41, S204 and WA) were applied by dipping the roots and rhizome in a conidial suspension, by injecting a conidial suspension into the plant rhizome and by growing the plants in sterile soil mixed with B. bassiana-colonized rice substrate. Four weeks after inoculation, plant growth parameters were determined and plant tissue colonization assessed through re-isolation of B. bassiana. All B. bassiana strains were able to colonize banana plant roots, rhizomes and pseudostem bases. Dipping plants in a conidial suspension achieved the highest colonization with no negative effect on plant growth or survival. Beauveria bassiana strain G41 was the best colonizer (up to 68%, 79% and 41% in roots, rhizome and pseudostem base, respectively) when plants were dipped. This study demonstrated that, depending on strain and inoculation method, B. bassiana can form an endophytic relationship with tissue culture banana plants, causing no harmful effects and might provide an alternative method for biological control of C. sordidus.  相似文献   
38.
沈阳城市绿地系统的景观生态评价   总被引:3,自引:0,他引:3  
运用景观生态学原理和方法,选取多样性指数、均匀度指数、破碎度指数、分离度指数、分维度指数、连通性指数等8个景观格局指数对沈阳市城市绿地系统的景观格局进行分析。结果表明:沈阳城市绿地景观总体表现为绿地率较低,绿地斑块分布不均衡,景观结构不合理,破碎度较高,分维数较低,景观类型较齐全,均匀度较低,景观分离度较小。针对存在的问题,提出了沈阳城市绿地景观生态规划建议。  相似文献   
39.
北京地区黑鹳越冬期的取食行为   总被引:6,自引:0,他引:6  
2004年12月至2005年3月在北京十渡地区的二渡和涞水县野三坡两地采用目标取样法对越冬期黑鹳(Ciconia nigra)的取食行为进行了观察。每星期观察一次,累计观察246 h。黑鹳觅食处水深5~40 cm左右,以鱼类和螺类为食,其中鱼类占90%以上;平均每小时进食20次左右,黑鹳在两个研究地点取食的食物没有差别(P=0.439>0.05)。黑鹳取食长度小于4 cm的鱼类最多,占取食总次数的65.0%。成体和亚成体对不同大小鱼类的取食比例无差异(小于4 cm的鱼类,P=0.513>0.05;5~8 cm,P=0.979>0.05;≥9 cm,P=0.657>0.05)。在成体与亚成体对不同体型鱼类的搜寻时间中,成体搜寻较小食物的时间短于亚成体(P=0.008<0.05)。对食物的处理时间随着鱼类大小递增而延长,亚成体在处理较小食物上花费的时间相对较长(小于4 cm的鱼P=0.002<0.05;5~8cm的鱼P=0.001<0.05),表明亚成体的取食经验不足。保护越冬期黑鹳的最佳对策是减少对其取食活动和取食地的人为干扰。  相似文献   
40.
A slightly creamy, melanogenic, gram-negative, aerobic bacterium was isolated from seawater sample collected in the Karadag Natural Reserve of the Eastern Crimea, the Black Sea. The novel organism was chemoorganotrophic, had no obligate requirement in NaCl, tolerated to 12% NaCl, grew between 10 and 45 degrees C, was slightly alkaliphilic, and was not able to degrade starch, gelatin, agar, and Tween 80. 16S rRNA gene sequence-based analyses of the new organism revealed that Oceanimonas doudoroffii ATCC 27123T, Oceanimonas baumanii ATCC 700832T, and Oceanisphaera litoralis DSM 15406T were the closest relatives (similarity around 97%-96%). The G + C content of the DNA of the strain 31-13T was 55.5mol%. Phosphatidylethanolamine (49.0%), phosphatidylglycerol (41.8%), and diphosphatidylglycerol (9.2%) were the predominant phospholipids. The major fatty acids were 16:0 (24.1%), 16:1omega7 (40.3%), and 18:1omega7 (29.2%). On the basis of the significant differences demonstrated in the phenotypic and chemotaxonomic characteristics, it is suggested that the bacterium be classified as a novel species; the name Oceanimonas smirnovii sp. nov. is proposed. The type strain is 31-13T (UCM B-11076T = LMG 22147T = ATCC BAA-899T).  相似文献   
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