"城中村"土地经营的探讨——以湖北省武汉市为例

“城中村”具有丰富的存量土地资源,内涵挖潜“城中村”土地．能有效地缓解城市化进程中出现的用地矛盾,实现其土地资产价值．同时,政策保障、科学规划与市场引导也是其改造的关键动力武汉市采取政策指导、引入社会力量、均衡利益分配等措施．经营“城中村”土地资源．取得了良好的效果。     

景观设计的人文要素概念初探

在了解人文概念的基础上,文章确立了景观设计的人文要素概念,以及景观设计概念与文明进程,并对其在景观设计中的地位和意义进行了阐明,进而理顺景观设计的人文要素与其他要素的关系是十分必要的。     

生物絮凝剂产生菌节杆菌LF-Tou 2葡萄糖基转移酶的性质与化学修饰

节杆菌LF-Tou2葡萄糖基转移酶是控制絮凝剂聚糖合成的酶。通过对细胞超声破碎使酶释放,经Sephadex G200凝胶色谱和DEAE-Sepharose Fast Flow离子交换色谱对酶进行了纯化。对酶学特性进行了分析,并用5种化学修饰剂对酶分子中5种不同氨基酸残基与催化活性之间的关系进行了研究。结果表明:该酶的分子质量为14315Da;样品中w(α-螺旋)=31.7%,w(β-转角)=34.1%,w(无规卷曲)=34.2%。Km为2.752μmol,Vmax为58.056μmol/min;Mn2 是酶活性强有力的激活剂,Fe2 次之。酪氨酸和二硫键是酶分子的结构基团,色氨酸、巯基和组氨酸是酶活力的必需基团,在必需基团中色氨酸最关键。     

Phytochemical composition and antimicrobial activities of the essential oils from Satureja subspicata Vis. growing in Croatia

The present study describes the phytochemical profile and antimicrobial activity of Satureja subspicata Vis. essential oils, collected in Dalmatia (Croatia). Three samples of essential oils were obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC–MS. From the 24 compounds representing 97.47% of the oils, carvacrol (16.76%), α-pinene (13.58), p-cymene (10.76%), γ-terpinene (9.54%) and thymol methyl ether (8.83%) appear as the main components. The oils also contained smaller percentages of myrcene, linalool, β-caryophyllene, limonene, geranyl acetate, 1-Octen-3-ol, nerol, thymol and borneol. Furthermore, antimicrobial activity of the oil was evaluated using agar diffusion and broth microdilution methods. The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria and 9 fungal strains. Gram-positive bacteria are more sensitive to the investigated oil, with a range of 0.09 to 6.25 μl/ml than Gram-negative bacteria in the range which is significantly higher from 1.56 to 25.00 μl/ml. Results presented here may suggest that the essential oil of S. subspicata possesses antimicrobial properties, and is therefore a potential source of antimicrobial ingredients for the food and pharmaceutical industry.     

Characterisation of Staphylococcus aureus strains from milk and goat cheese and evaluation of their inhibition by gallic acid,nisin and velame of the Brazilian caatinga

Twenty isolates from milk and goat cheese were confirmed as Staphylococcus aureus. These isolates were characterised for phenotypic properties related to cell adhesion and for the presence of enterotoxin production, intercellular adhesion and β‐lactam resistance genes. Staphylococcus aureus L47 showed cell adhesion ability and positivity for the sec, sed, icaD, mecA and blaZ genes. Three antimicrobial compounds were tested singly or in pairs for growth control of strain L47: gallic acid (GA), nisin and essential oil (EO) of Croton heliotropiifolius (velame). At 24 h, EO and EO + nisin showed higher inhibitory activity against S. aureus L47 in goat milk.     

Anticonvulsant activity of furanocoumarins and the essential oil obtained from the fruits of Heracleum crenatifolium

The anticonvulsant activity of furanocoumarins, coumarin mixture and the essential oil obtained from the fruits of Heracleum crenatifolium was examined against maximal electroshock (MES)-induced seizures in mice. Bergapten showed significant anticonvulsant activity. The furanocoumarins isolated from the fruits of the plant were identified using thin-layer chromatography, melting points and spectroscopic methods (IR, MS, ¹H NMR) as isobergapten (1), pimpinellin (2), bergapten (3), isopimpinellin (4), sphondin (5) and byak-angelicol (6). The essential oil content of the fruits were found as 5.5%. Twenty-two compounds representing 99.3% of the essential oil obtained from the fruits of H. crenatifolium were determined and the major components were identified as octanol and octyl acetate (3.1% and 88.4% respectively) by GC and GC–MS.     

The anticarcinogenic potential of essential oil and aqueous infusion from caper (Capparis spinosa L.)

The present study assessed the influence of essential oil and aqueous infusion from wild-grown caper (Capparis spinosa L.) on cell growth, NF-κB activation, apoptosis and cell cycle in the human colon carcinoma cell line, HT-29. Methyl isothiocyanate (92.06%), a degradation product of glucosinolate glucocapparin, was detected as major component of essential oil from caper leaves and flower buds. Aqueous infusion of caper showed an interesting and variegate compositional pattern containing several phenolic compounds, among which a flavonol glycoside, rutin (quercetin 3-O-rutinoside, 50.7%) and 5-caffeoyl-quinic acid (chlorogenic acid, 17.5%) were detected as dominant. Caper essential oil and aqueous infusion showed time- and dose-dependent high inhibitory effect on HT-29 cell proliferation. In addition, they induced the inhibition on nuclear factor κB (NF-κB) activity in a dose-dependent manner, while they did not show any effect on apoptosis in HT-29 cells. Flow cytometric analysis indicated that treatment with caper essential oil and aqueous infusion resulted in G₂/M cell cycle arrest in a dose-dependent manner. Presented results suggest that caper contains volatile and non-volatile compounds which potentially can play an important role in colon cancer prevention.     

Plant products as fumigants for stored-product insect control

Research studies on plant essential oils and their constituents as fumigants, i.e., compounds acting on target insects in the vapour or gaseous phase, against stored-product insects have been reviewed. Fumigant toxicity tests conducted with essential oils of plants (mainly belonging to Apiaceae, Lamiaceae, Lauraceae and Myrtaceae) and their components (cyanohydrins, monoterpenoids, sulphur compounds, thiocyanates and others) have largely focused on beetle pests such as Tribolium castaneum, Rhyzopertha dominica, Sitophilus oryzae and Sitophilus zeamais but little or no attention has been paid towards moths such as Corcyra cephalonica and Sitotroga cerealella. Adults were generally susceptible, whereas, eggs were either tolerant or highly susceptible depending on insect species and the type of essential oil or component. The essential oils proved effective in mixture with CO₂ or ethyl formate. Mode of action studies on monoterpenoids indicate inhibition of acetylcholinesterase enzyme activity as the major site of action. Although, in laboratory tests with adult insects, some of the plant compounds have shown insect toxicity comparable to methyl bromide or chloropicrin, their physical properties such as high molecular weight as well as high boiling point and very low vapour pressure are barriers for application in large-scale fumigations. Plant products, therefore, have the potential for small-scale treatments, space fumigations and as adjuvants for conventional fumigants. The constraints including lack of data for single or multiple components of essential oils on sorption, tainting and residues in food commodities, and registration protocols have been highlighted. The use of egg and pupal stages or preferably mixed-age cultures of target insects in screening tests with any new plant essential oil/compound has also been stressed.     

Variations in essential oil and fatty acid composition during Myrtus communis var. italica fruit maturation

The essential oil and fatty acid composition of Myrtus communis var. italica fruit during its ripening was determined. The effect of the harvesting time on some physical properties of Myrtus fruits, fruit weight and moisture content, were significant. The increase of fruit weight (from 2.54 to 8.79 g% fruits) during ripeness was correlated positively with that of moisture content (from 28% to 72%). Fruit essential oil yields varied from 0.003% to 0.01% and showed a remarkable increase at 60 days after flowering to reach a maximum of 0.11%. Forty-seven volatile compounds were identified in fruit essential oils; 1,8-cineole (7.31–40.99%), geranyl acetate (1.83–20.54%), linalool (0.74–18.92%) and α-pinene (1.24–12.64%) were the main monoterpene compounds. Total fatty acid contents varied from 0.81% to 3.10% during fruit maturation and the predominant fatty acids were linoleic (12.21–71.34%), palmitic (13.58–37.07%) and oleic (6.49–21.89%) acids. The linoleic acid proportions correlated inversely with palmitic and oleic acids during all the stages of ripening.     

In Vitro Determination of the Antifungal Activity of Artemisia campestris Essential Oil from Algeria

The chemical composition of the essential oil isolated from the aerial parts of Artemisia campestris from Algeria and its antifungal activity against 10 filamentous fungal strains were investigated. The A. campestris essential oil was obtained in a yield of 0.71% (v/w). The major constituents of the oil were α-pinene (18.65%), β-pinene (16.78%), β-myrcene (17.34%), and germacrene D (10.34%). Our study showed that A. campestris essential oil was a potent antifungal agent against some pathogenic fungal species. Fusarium graminearum was the most sensitive strain to A. campestris essential oil with minimal inhibitory concentration and minimal fungicidal concentration values of 1.25 µL/mL (v/v). The essential oil also exhibited a strong fungicidal activity against the tested fungi, except for Penicillium citrinum, P. viridicatum, and Aspergillus niger (MFC >20 µL/mL). Our findings suggested the application of A. campestris essential oil as a biofungicide in order to reduce the dependence on synthetic fungicides and ensure food safety and quality.